GL Concrete Segmental Lining System 2011 02

Austrian Society for Concrete- and Construction Technology

Concrete Segmental Lining Systems G

UIDE

LINE

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Österreichischen Vereinigung für Beton- und Bautechnik (ÖVBB)

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Austrian Society for Concrete- and Construction Technology

Edition: February 2011

Publisher: Austrian Society for Concrete- and Construction Technology A-1040 Wien, Karlsgasse 5 Tel.: +43/1/504 15 95 Fax: +43/1/504 15 95-99 E-Mail:[email protected] http://www.concrete-austria.com

Guideline

Concrete Segmental Lining Systems

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Allrightsreserved,especiallytherightsofreproductionanddistributionas well as translation.

No part of this publication may be reproduced(byphotocopying,micro-filmingoranyothermeans)

or stored, processed or copied by any electronic system without permissionin writing from the publisher.

If the document is purchased in electronic form, its storage on data carriers is permitted asprovidedforinthelicenceagreement.

Although utmost care has been taken in drafting this publication, we are not able to guarantee the accuracy, completeness and correctness of the information contained therein.

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Preface

In February 2006, the Working Group on Concrete in Tunnel Construction of the Austrian Association for Concrete and Construction Technology (Österreichische Vereinigung für Beton- und Bautechnik, ÖVBB) set up a Working Party on Concrete Segmental Lining Systems. This working party was mandated to draft an ÖVBB Guideline for Concrete Segments.

On the one hand, the new Guideline was to build on the findings of the ÖVBB State-of-the-Art Report on Segments, incorporating the most recent developments and practical experience. On the other hand, it was intended as a normative document providing recommendations for construction work.

To this end, a technical body comprising engineering consultants and staff members of engineering offices, representatives of universities as well as testing and research institutions, contractors and public clients was set up and tasked with elaborating the Guideline.

Besides the state of the art of relevant international guidelines and standards, the working party took into account current findings and experience from Austrian projects successfully executed with segmental lining systems over the last five years, such as the Wienerwald Tunnel, the Perschling chain of tunnels, the upgrading of the Lower Inn Valley railway line, the Wiental collector, the Vienna Underground and a number of power plant tunnels and galleries. Moreover, international experience gained by Austrian tunnelling engineers in their work abroad was also incorporated.

The present Guideline is intended as a practice-oriented set of rules and recommendations following the tradition of the Austrian Association for Concrete and Construction Technology. The members of the working party not only put in many hours of unpaid work, but also generously shared their personal know-how and expertise with their colleagues in the interest of achieving a high common engineering standard. Their efforts deserve our sincere thanks.

The frequent and often controversial technical discussions in the course of the drafting process have shown that “segmental lining” is a complex subject that defies an easy one-fits-all solution. Therefore, the Guideline had to be limited in both content and scope. This is all the more justified as segment technology is advancing rapidly and it would be inappropriate to hinder this development by adopting too rigid an approach. The very fact that the Guideline will continue to evolve is an indication of its quality rather than a deficiency.

This Guideline, which is the product of the commitment and dedication of Austrian engineering colleagues working in this field, is intended as a supporting instrument for the design and implementation of segmental lining projects.

Johann Lemmerer Alois Vigl

Vienna, February 2009 Schruns, February 2009

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Contributors

Dipl.-Ing. Dietmar BACH IGT Geotechnik und Tunnelbau ZT GmbH, Salzburg

Dipl.-Ing. Paul BONAPACE ILF Beratende Ingenieure ZT GmbH, Innsbruck

Dipl.-Ing. Dr. Stefan L. BURTSCHER Technische Versuchs- und Forschungsanstalt GmbH, Vienna University of Technology

Dipl-.Ing. Dr. Arnold FINK ÖBB Infrastruktur Bau AG, Innsbruck

Dipl.-Geol. Thomas GANGKOFNER ÖBB Infrastruktur Bau AG, Innsbruck

Dipl.-Ing. Dr. Kurt HECHENBLAICKNER ILF Beratende Ingenieure ZT GmbH, Innsbruck

Dipl.-Ing. Gerhard HOBIGER Wiener Linien GmbH & Co KG, Vienna

Dipl.-Ing. Dr. Johannes HORVATH Alpine Bau, Salzburg

O.Univ.-Prof. Dipl.-Ing. Dr. Hans Georg JODL Vienna University of Technology

Dipl.-Ing. Hans KÖHLER Porr Tunnelbau GmbH, Vienna

Dipl.-Ing. Dr.sc. Davorin KOLIC Neuron Consult ZT, Pasching

O.Univ.-Prof. Dipl.-Ing. Dr. Johann KOLLEGGER Vienna University of Technology

Dipl.-Ing. Andreas LANGE Strabag AG, Spittal/Drau

Dipl.-Ing. Dr. Harald LAUFFER Porr Tunnelbau GmbH, Vienna

Ing. Wolfgang LEHNER Strabag AG, Vienna

Dipl.-HTL-Ing. Johann LEMMERER ÖBB Infrastruktur Bau AG, Vienna

Dipl.-Ing. Dr. Wolfgang LINDLBAUER Ingenieurbüro Dr. Wolfgang Lindlbauer, Vienna

O.Univ.-Prof. Dipl.-Ing. Dr. Walter LUKAS University of Innsbruck

Dipl.-Ing. Alfred F. MAYERHOFER PCD ZT-GmbH, Vienna

Dipl.-Ing. Vladislav MIHAYLOV iC Consulenten ZT GmbH, Vienna

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Dipl.-Ing. Roland MURR Pöyry Infra GmbH, Strass i.Z.

Dipl.-Ing.(FH) Georg OCKERMÜLLER Gerocret-Ockermüller Betonwaren GmbH, Langenlebarnd

Dipl.-Ing. Dr. Walter PICHLER Material Consult, Hart

Dipl.-Ing. Patrick POSCH Katzenberger Beton- und Fertigteilwerk Nfg GmbH & Co KG, Innsbruck

Dipl.-Ing. Dr. Bernhard RABENREITHER MABA Fertigteilindustrie GmbH, Sollenau

Dipl.-Ing. Christian RAUCH Arge Bautech, Vienna

Dipl.-Ing. Robert SCHMIED Wietersdorfer & Peggauer Zementwerke, Peggau

Dipl.-Ing. Dr. Alfred SCHULTER D2 Consult International GmbH, Linz

Dipl.-Ing Walter SKALA Fritsch, Chiari & Partner ZT GmbH, Vienna

Dipl.-Ing. Michael STEINER ASFINAG Baumanagement GmbH, Vienna

Dipl.-Ing. Dr. Markus TESTOR ÖBB Infrastruktur Bau AG, Innsbruck

Dipl.-Ing. Gerhard URSCHITZ Strabag AG, Vienna

Dipl.-Ing. Dr. Alois VIGL viglconsult ZT, Schruns

Dipl.-Ing. Dr. Herbert WALTER IGT Geotechnik und Tunnelbau ZT GmbH, Salzburg

Dipl.-Ing. Hanns WAGNER ÖBB-Infrastruktur Bau AG, Vienna

Dipl.-Ing. Oliver K. WAGNER ÖBB Infrastruktur Bau AG, Graz

Dipl.-Ing. Gerfried WANNEMACHER Porr Tunnelbau GmbH, Vienna

Dipl.-Ing. Wolfgang WEBER Jäger Bau GmbH, Schruns

Dipl.-Ing. Friedrich WIESHOLZER Federal Ministry of Transport, Innovation and Technology, Vienna

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Guideline Concrete Segmental Lining Systems Edition February 2011

CONTENT 0 PRELIMINARY REMARKS .................................................................................................................... 11 SCOPE ................................................................................................................................................ 22 DEFINITIONS ...................................................................................................................................... 2

2.1 Terminology ..................................................................................................................................... 22.2 Abbreviations .................................................................................................................................. 5

3 SEGMENTAL SYSTEMS ....................................................................................................................... 63.1 Building materials ............................................................................................................................ 63.2 Segmental lining systems ................................................................................................................ 6

3.2.1 Segmental systems with fixed diameter ........................................................................................ 63.2.2 Segmental systems with variable diameter ................................................................................... 63.2.3 Lining systems with invert segment ............................................................................................... 63.2.4 Single-shell segmental lining systems ............................................................................................ 63.2.5 Double-shell segmental lining systems .......................................................................................... 7

3.3 Segment geometry .......................................................................................................................... 73.3.1 Rectangular system ........................................................................................................................ 73.3.2 3.3.2 Trapezoidal system ................................................................................................................ 73.3.3 Rhomboidal system ........................................................................................................................ 73.3.4 Hexagonal system .......................................................................................................................... 8

3.4 Ring geometry ................................................................................................................................. 83.4.1 Parallel ring system ........................................................................................................................ 83.4.2 Parallel ring system with corrective rings ...................................................................................... 83.4.3 Right/left system ............................................................................................................................ 83.4.4 Universal ring system ..................................................................................................................... 8

3.5 Waterproofing function of the segmental lining ............................................................................. 93.5.1 Impermeable segment shell ........................................................................................................... 93.5.2 Functionally sealed segment shell .................................................................................................. 93.5.3 Drained segment shell .................................................................................................................... 93.5.4 Unsealed segment shell .................................................................................................................. 9

3.6 Mixed systems ................................................................................................................................. 93.7 System requirements depending on the construction method ...................................................... 9

3.7.1 General remarks ............................................................................................................................. 93.7.2 Segmental systems for shieldless (open) TBM drives (TBM-O) ...................................................... 93.7.3 Segmental systems for single-shield TBM drives (TBM-S) .............................................................. 93.7.4 Segmental systems for double-shield TBM drives (TBM-DS) ........................................................ 103.7.5 Segmental systems for shield machines with active face support (SM) ....................................... 10

3.8 Waterproofing requirements to be met by the segmental lining ................................................. 104 ACTIONS .......................................................................................................................................... 12

4.1 General remarks ............................................................................................................................ 124.2 Permanent actions ........................................................................................................................ 13

4.2.1 Deadweight .................................................................................................................................. 134.2.2 Rock load ...................................................................................................................................... 134.2.3 Water pressure ............................................................................................................................. 134.2.4 Swelling and expansion pressure ................................................................................................. 134.2.5 Recovery forces due to gaskets, bolt forces ................................................................................. 134.2.6 Buildings ....................................................................................................................................... 144.2.7 Future buildings / embankments / earth removal / neighbouring cavities .................................. 14

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4.3 Variable actions (on finished structure) ........................................................................................ 144.3.1 Traffic loads in the tunnel ............................................................................................................ 144.3.2 Traffic loads above ground ........................................................................................................... 144.3.3 Pressure and suction load ............................................................................................................ 144.3.4 Temperature influences ............................................................................................................... 144.3.5 Internal water pressure ................................................................................................................ 14

4.4 Variable actions and combinations of actions during construction .............................................. 154.4.1 Loading of segments from production to installation .................................................................. 154.4.2 Installation and thrust forces ....................................................................................................... 154.4.3 Support pressure and annulus grouting pressure ........................................................................ 154.4.4 Rock load on the tunnel roof with partially bedded segment ring ............................................... 154.4.5 Uplift of the tunnel tube in grouting mortar ................................................................................ 154.4.6 Loading of the invert area by back-up equipment of the TBM and logistic systems .................... 154.4.7 Injection pressure due to post-injection and rock rehabilitation .................................................. 154.4.8 Buoyant forces due to concrete placement for the inner shell ..................................................... 15

4.5 Exceptional actions ........................................................................................................................ 154.5.1 Impact loads ................................................................................................................................. 154.5.2 Fire loads ...................................................................................................................................... 164.5.3 Earthquake ................................................................................................................................... 164.5.4 Flooding of the tunnel tube .......................................................................................................... 164.5.5 Explosion ...................................................................................................................................... 164.5.6 Other disaster scenarios ............................................................................................................... 16

5 CALCULATION AND DESIGN OF SEGMENTS ...................................................................................... 175.1 General remarks ............................................................................................................................ 175.2 Calculation methods and models .................................................................................................. 17

5.2.1 General remarks ........................................................................................................................... 175.2.2 Selection of the calculation method ............................................................................................. 175.2.3 Calculation methods for rock masses with bedding planes and discontinuities .......................... 175.2.4 Calculation of the tunnel shell ...................................................................................................... 175.2.5 Stiffness of the segment ring ........................................................................................................ 185.2.6 Structural consideration of radial joints ....................................................................................... 195.2.7 Tolerances and imperfections ...................................................................................................... 21

5.3 Combination of actions, design situations and partial safety factors ........................................... 215.4 Verification of load-bearing capacity ............................................................................................ 21

5.4.1 General remarks ........................................................................................................................... 215.4.2 Design of radial and circumferential joints .................................................................................. 225.4.3 Coupling forces ............................................................................................................................. 225.4.4 Indications for fire design ............................................................................................................. 22

5.5 Verification of serviceability .......................................................................................................... 225.5.1 General remarks ........................................................................................................................... 225.5.2 Limitation of crack width .............................................................................................................. 235.5.3 Limitation of deformations .......................................................................................................... 23

5.6 Structural design of segments ....................................................................................................... 236 CONCRETE ....................................................................................................................................... 24

6.1 General remarks ............................................................................................................................ 246.2 Requirements ................................................................................................................................ 24

6.2.1 Strength classification .................................................................................................................. 246.2.2 Exposure classification ................................................................................................................. 246.2.3 Early strength ............................................................................................................................... 256.2.4 Maximum grain size ..................................................................................................................... 256.2.5 Consistency ................................................................................................................................... 256.2.6 Surface characteristics ................................................................................................................. 25

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6.3 Constituent materials of concrete ................................................................................................. 266.3.1 Cement ......................................................................................................................................... 266.3.2 Mineral aggregates ...................................................................................................................... 266.3.3 Water ........................................................................................................................................... 266.3.4 Additives ....................................................................................................................................... 276.3.5 Admixtures ................................................................................................................................... 276.3.6 Fibres ............................................................................................................................................ 27

6.4 Testing ........................................................................................................................................... 276.4.1 Pre-construction testing ............................................................................................................... 276.4.2 Conformity testing ........................................................................................................................ 296.4.3 Identity testing ............................................................................................................................. 30

7 JOINT DESIGN .................................................................................................................................. 317.1 Types of joints and their structural design .................................................................................... 31

7.1.1 Radial joints .................................................................................................................................. 317.1.2 Circumferential joints ................................................................................................................... 317.1.3 Shapes of joints ............................................................................................................................ 327.1.4 Keystone joint ............................................................................................................................... 33

7.2 Joint sealing systems ..................................................................................................................... 347.2.1 Systems with unsealed joints ....................................................................................................... 347.2.2 Systems with mortar-filled joints (combined with injection) ........................................................ 347.2.3 Systems with waterproof lining .................................................................................................... 34

7.3 Centring aids and connectors ........................................................................................................ 367.3.1 Purpose of connectors and centring aids ..................................................................................... 367.3.2 Movable centring aids .................................................................................................................. 367.3.3 Dowels .......................................................................................................................................... 377.3.4 Bolts ............................................................................................................................................. 37

7.4 Joint inserts .................................................................................................................................... 387.5 Joint adjustment plates ................................................................................................................. 38

8 PRODUCTION .................................................................................................................................. 398.1 Production technology .................................................................................................................. 39

8.1.1 Mixing plant ................................................................................................................................. 398.1.2 Formwork ..................................................................................................................................... 398.1.3 Reinforcement .............................................................................................................................. 398.1.4 Concreting and curing process ..................................................................................................... 408.1.5 Production tolerances .................................................................................................................. 418.1.6 Joints / Gaskets ............................................................................................................................ 41

8.2 Handling and storage in the production plant .............................................................................. 418.3 Testing and production controls ................................................................................................... 42

8.3.1 Testing of building materials ........................................................................................................ 428.3.2 Testing of structural components ................................................................................................ 428.3.3 Concrete properties ...................................................................................................................... 428.3.4 Geometry ...................................................................................................................................... 428.3.5 Acceptance of segments produced .............................................................................................. 42

8.4 Repair during production (in plant) ............................................................................................... 43

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9 INSTALLATION ................................................................................................................................. 439.1 General remarks ............................................................................................................................ 43

9.1.1 Storage ......................................................................................................................................... 439.1.2 Transport ...................................................................................................................................... 43

9.2 Building of the segment ring – Mechanical engineering requirements ........................................ 449.2.1 General remarks ........................................................................................................................... 449.2.2 Thrust jacks .................................................................................................................................. 449.2.3 Segment gantry and erector ........................................................................................................ 449.2.4 Tailskin seal .................................................................................................................................. 45

9.3 Loads due to tunnel advance ........................................................................................................ 459.4 Segment control and inspection .................................................................................................... 45

9.4.1 At the construction site above ground ......................................................................................... 459.4.2 In the tunnel prior to installation underground ........................................................................... 469.4.3 Inspections after installation ........................................................................................................ 46

9.5 Repair of segments ........................................................................................................................ 469.5.1 Definition of the most frequent types of defects .......................................................................... 469.5.2 Types of defects ............................................................................................................................ 519.5.3 Repair of defects .......................................................................................................................... 529.5.4 Repair matrix ................................................................................................................................ 52

10 BACKFILLING OF THE ANNULUS ....................................................................................................... 5610.1 General remarks ............................................................................................................................ 5610.2 Support conditions, bedding principles and requirements ........................................................... 56

10.2.1 Support conditions ....................................................................................................................... 5610.2.2 Bedding principles ........................................................................................................................ 5610.2.3 Bedding requirements .................................................................................................................. 5710.2.4 Monitoring and control of filling level and bedding ..................................................................... 59

10.3 Annulus grouting mortar ............................................................................................................... 6010.3.1 Properties ..................................................................................................................................... 6010.3.2 Mortar constituents ..................................................................................................................... 6010.3.3 Checking and testing – Mortar ..................................................................................................... 61

10.4 Pea gravel ...................................................................................................................................... 6210.4.1 Requirements ............................................................................................................................... 6210.4.2 10.4.2 Inspection and testing ....................................................................................................... 63

10.5 Sealing of joints ............................................................................................................................. 6410.5.1 General remarks ........................................................................................................................... 6410.5.2 Requirements to be met by joint mortar ...................................................................................... 64

10.6 Post-grouting of annulus backfill ................................................................................................... 6410.6.1 Requirements ............................................................................................................................... 6410.6.2 Constituent materials ................................................................................................................... 6510.6.3 Inspection and testing .................................................................................................................. 65

10.7 Grout injections for rock improvement ......................................................................................... 6611 GEOMETRICAL TOLERANCES OF THE SEGMENT ................................................................................ 67

11.1 Segment geometry ........................................................................................................................ 6711.2 Setting of tolerances ...................................................................................................................... 69

11.2.1 Formwork tolerances ................................................................................................................... 6911.2.2 Segment deformation tolerances ................................................................................................. 6911.2.3 Tolerances for segment details .................................................................................................... 71

11.3 Measuring programme .................................................................................................................. 7111.3.1 Manual measurements ................................................................................................................ 7111.3.2 3D measurements ........................................................................................................................ 7111.3.3 Test ring ....................................................................................................................................... 7211.3.4 Test frequencies ........................................................................................................................... 72

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12 IMPERFECTIONS AND SYSTEM TOLERANCES .................................................................................... 7312.1 Design phase .................................................................................................................................. 73

12.1.1 Influences on the structural analysis ............................................................................................ 7312.1.2 Imperfections and eccentricities in the radial joint ...................................................................... 7312.1.3 Imperfections and eccentricities in the circumferential joint ....................................................... 7312.1.4 Interaction between connector – sealing strip – segment geometry ........................................... 7312.1.5 Influences of deformations and tolerances .................................................................................. 7312.1.6 Influences due to storage and installation ................................................................................... 74

12.2 Construction phase ........................................................................................................................ 7512.2.1 Segment production ..................................................................................................................... 7512.2.2 Transport and storage .................................................................................................................. 7512.2.3 Installation – ovalisiation ............................................................................................................. 7512.2.4 Installation – misalignment .......................................................................................................... 7612.2.5 Installation – open joint ............................................................................................................... 77

12.3 Tolerances based on system requirements ................................................................................... 7712.3.1 Geometric system consistency ..................................................................................................... 7712.3.2 Structural system consistency ...................................................................................................... 7712.3.3 Functional system consistency ..................................................................................................... 78

13 STANDARDS, GUIDELINES, BIBLIOGFAPHY ....................................................................................... 7913.1 Standards referred to in the text ................................................................................................... 7913.2 Guidelines and regulations ............................................................................................................ 8013.3 Additional standards to be taken into consideration .................................................................... 8113.4 Bibliography ................................................................................................................................... 82

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Austrian Society for Concrete and Construction Technology Page 1

0 PRELIMINARY REMARKS

In order to eliminate barriers to trade within the European Economic Area, the following principles have to be observed:

Products from Member States of the European Union as well as goods originating from EFTA countries belonging to the European Economic Area (EEA), which are not in conformity with this Guideline but have passed the tests and inspections performed and recognised in the Member States concerned, are regarded as equivalent, including such tests and inspections, provided the level of protection required in Austria in terms of safety, health and serviceability is reached and maintained on a permanent basis.

The testing institutions concerned must provide adequate and satisfactory guarantees of their technical qualification, their competence and their independence (e.g. according to ÖVE/ÖNORM EN ISO/IEC 17025). The body inviting tenders may demand the submission of German-language documents relating to tests and inspections performed as well as standards, technical guidelines and regulations governing products and/or goods of EU or EEA origin.

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Page 2 Austrian Society for Concrete and Construction Technology

1 SCOPE

This Guideline applies to the production of the lining or parts of the lining of underground structures from pre-cast concrete parts (segments).

In a single-shell lining system, the segmental lining assumes the function of initial ground support for the excavation and, at the same time, serves as its inner lining.

In a double-shell lining system, the excavation is usually supported by a segmental lining system with an additional cast-in-place inner lining. If initial ground support is already in place, a segmental lining can also be installed as an inner lining.

Combinations of single-shell and double-shell linings, i.e. a single-shell lining for the invert combined with a double-shell lining for the tunnel arch, are possible.

By analogy, this Guideline also applies to jacked pipes.

2 DEFINITIONS

2.1 Terminology

Support Support of the excavation. In a single-shell lining the support assumes the function of the inner lining.

Tunnel lining Structure consisting of the ground support and the inner lining.

Thrust ring The thrust ring serves to transmit the thrust forces to the segment ring.

Single-shell lining A single lining system meets all load-bearing and structural requirements (single-shell or single-pass method). No inner lining is applied (see also ÖVBB Guidelines “Sprayed Concrete”).

Single thrust jacks Individual thrust jacks or pairs of thrust jacks serving to transmit the thrust forces to the segment ring and/or facilitating installation.

Extrados Outer surface of the segment or the segment ring on the mountain side.

Pre-cast part Structural element manufactured under controlled conditions at a place other than the place of installation.

Joint End face of the segment and area of contact between segments.

Guide rails Assembly devices ensuring positive centring of the segments in the prepared radial joints.

Stroke Length of advance section, usually corresponding to the width of the segment.

Injection Filling of natural voids, fissures and cavities in the rock mass under pressure, without essentially changing the structure of the rock mass. Unlike in grouting, the pressure is kept constant over a pre-defined period of time.

Inner lining Two-dimensional inner structural element meeting structural and/or functional requirements, not serving for direct tunnel support and installed outside the driving area.

Inner tailskin seal Seal between the tailskin and the segment ring.

Outer tailskin seal Barrier between the tailskin and the rock mass.

Intrados Inner surface of the segment or the segment ring on the tunnel side.

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Conicity of the segment ring

Difference of developed surface between the maximum and minimum segment width in a ring, especially in tapered or conical rings.

Continuous (mechanised) driving

Tunnel driving by means of a tunnelling machine (tunnel boring machine, shield machine, etc.), with the individual operations of excavation, mucking and support installation being performed simultaneously. As a rule, the tunnel is excavated by a circular cutter head equipped with cutting tools.

Radial joint Joint in approximately axial direction between the individual elements (segments) of a segment ring.

Logistics The term “logistics” refers to the planning, installation and operation of a tunnelling site. It covers all operations relating to the transport, storage and handling of material, energy and products within and between construction sites, including the transport of manpower at a tunnelling site.

Blowhole A surface irregularity resulting from the entrapment of air at the surface of formed concrete (“open pore”).

Niche Lateral widening of the tunnel cross section (without connection to other structures), usually in the wall area; the design of the cross section depends on the function of the niche. Niches are provided for parking and turning, emergency call, fire alarm, rescue and fire extinguishing facilities, or for the installation of equipment and fittings, etc.

Ovalisation Deformation of an installed segment ring due to system-specific tolerances, ground pressure, grout pressure, segment deadweight or uplift.

Pea gravel Single-size gravel, usually filled into the annulus through holes in the segments behind the tailskin.

Test ring Complete segment ring, usually assembled in horizontal position, for test purposes.

Test segment Segment produced for test purposes to assess the production conditions and check the concrete formula determined through pre-construction testing (mixer, consistency before placement, formwork, etc.).

Crosscut Connecting structure between two tunnel tubes or between the tunnel tube and the shaft structure with special passages in the connecting area (standard wall connection) of the main tube. The cross section of the crosscut depends on its purpose. Crosscuts serve as vehicular and pedestrian passageways, escape routes, general access routes to underground station structures, etc.

Circumferential joint Joint between two adjacent segment rings approximately perpendicular to the tunnel axis.

Annular gap Space between the surrounding rock mass and the outer surface of the segments.

Round grain Round mineral aggregate comprising more than 50% of naturally rounded particles. The percentage of round grain is determined in percent by weight in a sample of at least 200 grains.

Shield driving Tunnelling by driving a shield body into the rock mass, applying different excavation methods and, if necessary, face-supporting measures.

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System-specific maximum internal water pressure

The system-specific maximum internal water pressure is the internal water pressure determined by the system (e.g. maximum impounding level) that cannot be exceeded.

Partial stroke Length of advance section as a fraction of segment width.

Segment Pre-cast part made of reinforced and non-reinforced concrete, steel or cast iron, used as lining for tunnels, galleries and shafts.

Segment gasket Sealing system consisting of sealing strips placed in one or more layers around the individual segment, ensuring permanent sealing of the tunnel tube against the ingress of water from the surrounding rock mass.

Segmental system Lining system for tunnels, galleries and shafts consisting of individual lining elements assembled into segment rings; in combination with the backfilling of the annulus, it provides the necessary support for the cavity.

Connectors Devices for temporary or permanent connection of two segments or segment rings in the radial and circumferential joints (e.g. bolts, dowels), working in tension and in shear.

Grouting Filling of artificially created cavities in the rock mass with grout under pressure.

Double-shell lining Tunnel lining consisting of two or more shell elements (double-shell or double-pass construction method) meeting different static and structural requirements (no bonding), installed in independent operations and by different methods (e.g. outer shell made of sprayed concrete or segments, inner shell made of in-situ concrete) (see also ÖVBB Guideline on “Sprayed Concrete”).

Cyclic (conventional) tunnelling

Tunnelling method in which the individual operations of excavation, mucking and support installation are performed consecutively and by means of different equipment. As a rule, the tunnel is excavated by drill and blast, excavator or roadheader.

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2.2 Abbreviations

AG Owner

AHWZ Prepared hydraulically active additives

AN Contractor

ATV Waste Water Technology Association (Abwassertechnische Vereinigung e.V.)

CEN European Committee for Standardisation

DIN German Institute for Standardisation

DVWK German Association for Water Management (Deutscher Verband für Wasserwirtschaft und Kulturbau e.V.)

DWA German Association for Water, Waste Water and Waste (Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V., successor to ATV and DVWK

EPDM Ethylene-propylene-diene monomer

GW Ground water

ISO International Standardisation Organisation

NATM New Austrian Tunnelling Method

NÖT Neue Österreichische Tunnelbaumethode

ÖBA Local construction supervision (by the owner)

QM Quality management

QSS Quality assurance system

SM Shield machine

TBM Tunnel boring machine

TBM-DS Double-shield tunnel boring machine

TBM-O Open tunnel boring machine

TBM-S Single-shield tunnel boring machine

TSI-SRT Technical Specification for Interoperability – Safety in Railway Tunnels

WDI Waterproof inner lining

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3 SEGMENTAL SYSTEMS

3.1 Building materials

The segmental systems currently in use in Austria are made of reinforced concrete. In other countries, segments are also made of non-reinforced concrete, fibre-reinforced concrete or combinations thereof.

3.2 Segmental lining systems

3.2.1 Segmental systems with fixed diameter

The tunnel shell is assembled entirely from segments. The radial joints are closed, which results in a fixed outer diameter. The annular space between the segment tube and the surrounding ground or rock mass is backfilled with appropriate annular filling material to ensure proper bedding of the segment ring.

3.2.2 Segmental systems with variable diameter

The tunnel shell is assembled entirely from segments. The radial joint are of variable width, which results in a variable outer diameter.

In the case of expanded segmental systems, the segments are pressed against the surrounding ground and/or rock mass by means of expansion elements (keystone).

In the case of compressible segmental systems, the radial joint, which is initially open, narrows or closes under the impact of the ground or rock mass load, which results in a reduction of the outer diameter. The annular space between the segment tube and the surrounding ground or rock mass is filled with appropriate material.

3.2.3 Lining systems with invert segment

A specially shaped invert segment is integrated into the tunnel shell, which provides immediate stabilisation of the tunnel floor, serves as a transport route and a water ditch. As a rule, the invert segment remains in place as part of the final lining.

When designing the segmental system with an invert segment, attention must be paid to the existence of a stationary special element in the tunnel floor.

Lining systems with conventional support (steel support, sprayed concrete, in-situ concrete) and an integrated invert segment only have a single pre-cast element incorporated in the tunnel floor, which usually fulfils the function of a transport route with a drainage trench and is integrated into the final lining as part of the load-bearing tunnel shell.

3.2.4 Single-shell segmental lining systems

On a medium-term basis and/or for the design lifetime of the structure, single-shell segmental lining systems assume all functions regarding the:

• stability of the excavation • load-bearing capacity of the tunnel structure • serviceability of the tunnel structure (tightness, durability) • quality requirements to be met by the tunnel structure (e.g. evenness, smoothness, ...)

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3.2.5 Double-shell segmental lining systems

In double-shell lining systems consisting of an outer segment shell and a load-bearing inner shell, the segmental support is combined with a cast-in-place concrete inner shell with full load-bearing function. As a rule, the segmental support serves to:

• support the excavation • ensure the stability of the tunnel structure (at least on a temporary basis) In double-shell lining systems with a segment shell on the outside and a functional shell on the inside the segmental support is combined with a cast-in-place concrete inner shell or a lining performing a specific function (e.g. fire protection, waterproofing, impact protection,…). As a rule, the outer segment shell serves to:

• support the excavation • ensure the stability of the tunnel structure • ensure the serviceability of the tunnel structure (tightness, durability) In double-shell lining systems with an invert segment the latter is usually combined with a cast-in-place or sprayed concrete inner shell. As a rule, the integrated invert segment assumes the following functions:

• immediate consolidation of the tunnel floor • supporting the excavation • stability of the tunnel structure • serviceability of the tunnel structure (tightness, durability)

3.3 Segment geometry

3.3.1 Rectangular system

Rectangular systems are assembled in rings of rectangular or slightly tapered segments (unilateral or bilateral conicity) with a wedge-shaped keystone or a rectangular invert keystone (Swiss stacking system). In general, the segments are assembled from bottom to top, alternating between left and right. • Main application: unsealed and sealed segmental linings; Swiss stacking system • Advantages: simple radial joint geometry (no helix), possibly with staggered radial joints • Disadvantages: assembly slightly more time-consuming than with rhomboidal system

3.3.2 3.3.2 Trapezoidal system

Trapezoidal systems are assembled from trapezoidal segments, with the first row as an open-tooth row and the second row inserted in the gaps to form a complete ring. • Main application: unsealed and sealed segmental linings • Advantages: non-continuous, staggered radial joints; every other segment acting as a keystone • Disadvantages: two “sharp”, exposed edges on each segment; alternating ring build (second row

inserted into gaps in first row)

3.3.3 Rhomboidal system

Rhomboidal systems are assembled from rhomboidal elements ring by ring, usually from bottom to top; assembly of the ring starts with a trapezoidal element and is completed with another such element as a keystone.

• Main application: unsealed and sealed segmental linings • Advantages: non-continuous, staggered radial joints, continuous ring build from bottom to top • Disadvantages: two “sharp” exposed edges of each segment

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3.3.4 Hexagonal system

Hexagonal systems are assembled continuously from hexagonal elements, alternating bottom/top and left/right, forming a tube. Each element serves as a keystone.

• Main application: unsealed single-shell segmental linings • Advantages: analogous geometry of all elements; each element acts as a keystone; no “sharp”

exposed edges; “coupled” stability of the tube through staggered circumferential joint; invert segment can be incorporated

• Disadvantages: space for 1.5-fold ring width needed within TBM tailskin; coupling demands high-quality assembly (“propagation of flaws”)

3.4 Ring geometry

3.4.1 Parallel ring system

In parallel ring systems the tube is assembled from parallel rings. For directional corrections and curves, packers are placed in the circumferential joints (shifting).

• Main application: unsealed single-shell and double-shell segmental linings • Advantages: simple construction; invert segment can be incorporated • Disadvantages: limited suitability for curves

3.4.2 Parallel ring system with corrective rings

Parallel ring systems with corrective rings are assembled from parallel rings forming a tube. Directional corrections and curves can be negotiated through the installation of corrective rings (up, down, left, right).

• Main application: unsealed single-shell and double-shell segmental linings • Advantages: simple construction; invert segment can be incorporated • Disadvantages: impermeability can only be achieved under certain conditions; different sets of

formwork required

3.4.3 Right/left system

Right/left systems are assembled from rings with one circumferential joint orthogonal to the tunnel axis and the other one inclined to the tunnel axis. The sequence of right-tapered and left-tapered rings produces a straight tunnel tube. A right/right ring sequence results in a curve to the right with a minimum system radius. A sequence of left/left rings produces a curve to the left with a minimum system radius. Upward and downward directional corrections are achieved through packers in the circumferential joints (“shifting”) or through rotation of the tapered segment ring by up to 90°.

• Main application: unsealed and sealed single-shell and double-shell segmental linings • Advantages: simple construction • Disadvantages: different sets of formwork required

3.4.4 Universal ring system

Universal ring systems are assembled from rings with circumferential joints inclined to the tunnel axis on one or both sides. Within the defined range of radii, spatial curves and changes in direction can be combined through controlled rotation in the circumferential joint.

Orientation at the circumferential joints is guided by direction marks; as a rule, it is calculated in advance by a ring-building software in combination with the TBM steering system.

• Main application: sealed single-shell linings • Advantages: can negotiate curves and can be made impermeable • Disadvantages: incorporation of invert segment is not possible; keystone must also be installed

in invert area

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3.5 Waterproofing function of the segmental lining

3.5.1 Impermeable segment shell

Pressurised segment shells are assembled from segments fit for this purpose combined with a joint sealing system to form an impermeable segmental lining.

Essential system components:

• Segments fit for this purpose, manufactured to tight tolerances to ensure their suitability for the intended use

• Joint gaskets with the required characteristics • Ring assembly to the required degree of accuracy • Anchored connectors providing the required prestressing effect

3.5.2 Functionally sealed segment shell

Functionally sealed segment shells are assembled from segments fit for the intended use. The type of sealing depends on whether backfilling and/or post-grouting of the annulus is required.

In general, functionally sealed systems do not qualify as impermeable.

3.5.3 Drained segment shell

Functionally sealed segment shells may require drainage for groundwater pressure relief. If the permeability of the functionally sealed system is not sufficient for this purpose, drainage holes can be drilled into the finished tunnel tube to drain the immediate surroundings of the tunnel.

3.5.4 Unsealed segment shell

Unsealed segment shells are assembled from segments fit for this purpose. In this case, closure of the joints only serves to prevent leakage of the material used to backfill the annular space (pea gravel). Impermeability to water or grout is not provided for.

3.6 Mixed systems

If waterproofing requirements vary along the length of the tunnel, one of the following options can be chosen, depending on the characteristics of the individual sections:

• Uniform segmental system with or without waterproofing • Different segmental systems for the individual sections with mostly uniform formwork

(formwork modifications) • Different treatment of the surrounding rock mass and installation of a uniform segmental system • Mixed systems

3.7 System requirements depending on the construction method

3.7.1 General remarks

Relevant system-specific relationships between the construction method used and the predominant segmental systems are outlined in the following.

3.7.2 Segmental systems for shieldless (open) TBM drives (TBM-O)

As a rule, no other than invert segments are installed in shieldless TBM drives (TBM-O).

3.7.3 Segmental systems for single-shield TBM drives (TBM-S)

In general, segmental systems with fixed or variable diameter are used in single-shield TBM drives (TBM-S). In a tunnel driven by means of a single-shield TBM (TBM-S), the thrust and steering forces are transmitted to the segment ring, which therefore has to be designed accordingly.

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3.7.4 Segmental systems for double-shield TBM drives (TBM-DS)

In general, segmental systems with fixed diameter are used in double-shield TBM drives (TBM-DS). However, the use of variable-diameter segmental systems is also possible.

If a double-shield TBM (TBM-DS) with grippers is used, the thrust and steering forces are activated through the gripper bracing without being transmitted to the segment ring, except in special cases. The segment rings can therefore be designed for different driving modes (with potential cost savings). Moreover, tunnel sections with invert segments only, possibly with additional local support elements (anchors, steel support, sprayed concrete), can be combined with other sections with full segmental lining.

3.7.5 Segmental systems for shield machines with active face support (SM)

In general, impermeable segment shells are installed in tunnels driven by shield machines with active face support. Use of a shield machine with active working face support requires the transmission of thrust and steering forces to the segment ring, which therefore have to be designed to absorb such forces.

3.8 Waterproofing requirements to be met by the segmental lining

Depending on the purpose and use of the structure, the requirements to be met by the support system, consisting of the sum total of all individual segments and the joints, have to be specified according to Table 3/1.

The design service life has to be determined for the entire structure. Depending on the requirements to be met, the durability of the individual components of the support system is to be verified. As a matter of principle, every effort should be made in the design and execution of the structure to use low-maintenance components that are easy to repair.

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Austrian S

ociety for Concrete and C

onstruction Technology P

age 11

Guideline C

oncrete Segm

ental Lining System

s E

dition February 2011

Require-ment Class

Short design-ation

Description of concrete surface

Assessment of moist spots Permissible defects

Permissible crack width

after installation

Requirement to be met by the

joint, max. water ingress

Examples of applications

AT1 Largely dry

Individual moist spots are visible (max. dull dark staining)

Upon touching with dry hand (flat), no traces of water remain on the hand.

1‰ of component surface allowed to be moist. Shades of moisture drying after max. 20 cm.

0.2 mm Impermeable

Single-shell lining meeting high waterproofing requirements. Portal areas according to Guideline on Inner Shell Concrete

AT2 Slightly moist

Individual shiny spots of moisture on the surface, visible and noticeable upon touching

Quantity of leaking water cannot be measured. Upon touching with dry hand, traces of water remain on the hand.

1% of component surface allowed to be moist. Individual, short shades of water, drying on the concrete surface.

0.25 mm

Moist, no running water in entire circum-ferential joint or individual radial joints

Single-shell lining with normal waterproofing requirements. Road and railway tunnels (excluding portal area)

AT3 Moist

Water drops draining from the surface, formation of long streaks of water

Draining water can be collected in vessels and its quantity measured

Max. quantity of water per defect must not exceed 0.2 l/h

0.3 mm Water dripping from individual spots

Single-shell lining without waterproofing function or double-shell lining

AT4 Wet Water running from individual spots

Draining water can be collected in vessels and its quantity measured

Max. quantity of water must not impair functionality of the structure.

0.3 mm Water running in some places

Single-shell lining without waterproofing function or double-shell lining as drained system

Tab. 3/1 Definition and description of the requirement classes to be met by the support system

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4 ACTIONS

4.1 General remarks

The actions and environment influences on segments and segmental linings can be classified as follows:

• Permanent actions: − Deadweight − Rock load − Water pressure − Swelling and expansion pressure − Recovery forces from seals, bolt forces − Existing buildings on the surface − Future buildings on the surface / embankments/ earth removal / neighbouring cavities

• Variable actions (finished structure): − Traffic loads in the tunnel − Traffic loads above ground − Pressure and suction forces − Temperature influences − Internal water pressure

• Variable actions during construction: − Loading due to de-moulding, handling, storage and interim transport − Installation and thrust forces − Support pressure and pressure from annulus grouting − Rock load on crown area with segment ring partially bedded − Uplift of tunnel tube in grout − Loading of invert area through back-up equipment and logistic systems − Injection pressure due to post-grouting and rock mass rehabilitation − Uplift from concrete placement for inner lining − Actions due to intersections with crosscuts and the like

• Exceptional actions: − Impact loads − Fire loads − Earthquake loads − Flooding of the tunnel tube − Explosion − Other disaster scenarios

• Construction work When determining the actions on the segmental lining, the relevant standards must also be taken into consideration. In the case of a multi-layered support system, it is important to bear in mind that different parts of the support can assume different functions. For calculation and design purposes, the most unfavourable combinations of actions are to be assumed.

If jacking pipes are used, the ATV provisions (General Technical Contract Terms and Conditions) apply additionally, as system-related constraints and thrust forces (above all in curves) must be taken into consideration.

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Richtlinie Tübbingsystem

e aus Beton

Ausgabe A

ugust 2009

4.2 Permanent actions

4.2.1 Deadweight

For deadweight calculation, a distinction must be made between deadweight loads during construction and in the finished structure. Imposed loads, e.g. backfilling of invert, spring-mass systems, intermediate ceilings, overhead line, have to be taken into consideration.

4.2.2 Rock load

The interaction between the rock mass and the support, which determines the states of stress and deformation of the rock mass and the support during tunnelling, e.g. swelling, expansion and creep of the rock mass, influence of dolines, karst formations and fault zones, should be modelled as true to reality as possible.

• Design case in soft ground: The idealised ground strata of the individual design cross sections are to be calculated on the basis of their deadweight and lateral tensioning, considering their geological history (coefficient of earth pressure at rest). Above ground water level and/or in areas where the ground water level has been lowered, the deadweight is to be calculated on the basis of wet bulk density. Below ground water level, in an area of hydrostatic water pressure distribution, the bulk density is to be calculated under buoyancy and, if possible, under flow pressure.

• Design case in hard rock: Anisotropic conditions in the surrounding rock mass, e.g. tunnel advance with strike, are to be taken into consideration in the calculation of loads. In general, the possibility of an unstable block forming along the strata and discontinuities above the tunnel crown (loosening zone) has to be borne in mind. In the case of a shallow overburden, shear failure at low stress levels is a possibility to be considered.

4.2.3 Water pressure

The calculation is to be performed on the basis of both minimum and maximum water pressure (i.e. most favourable and least favourable effect).

The design water levels (separate for ultimate limit state and serviceability limit state) are to be determined on the basis of appropriate stage hydrographs, considering the flood water levels of receiving water bodies, if any. The hydro-geological situation as well as ancillary geo-technical construction measures influencing the effect of ground water on the outer tunnel lining are to be taken into consideration.

The most unfavourable assumption is to be calculated separately for each design cross section. Project-specific features are to be taken into consideration.

As a matter of principle, the full hydrostatic water pressure is to be used as a basis for calculation. In the case of waterproofing measures as well as in drained tunnels, the unfavourable effect of a residual water pressure of at least 15 kN/m² in subsoil layers that cannot be completely drained is to be allowed for. In completely drainable subsoil layers, the possibility of the water level rising at least 1.50 m above the drainage target must be taken into consideration.

4.2.4 Swelling and expansion pressure

Depending on site conditions (mineralogical conditions, presence of water, etc.) swelling and expansion pressure has to be taken into consideration.

4.2.5 Recovery forces due to gaskets, bolt forces

In calculating the longitudinal strain on segments, the time-dependent recovery forces of the gaskets and the bolt forces have to be taken into consideration.

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4.2.6 Buildings

If buildings are present on the surface, the actual permanent loads as well as their standard-compliant live loads (allowing for standard-compliant reductions) have to be considered.

4.2.7 Future buildings / embankments / earth removal / neighbouring cavities

Future buildings / embankments / earth removal / neighbouring cavities within the range of influence above or to the sides of the tunnel structure are to taken into consideration after consultation with the Owner and/or determined on a project-specific basis. As a rule, future buildings should be at a distance of at least one tunnel diameter from the outer side of the segment.

For example, the following can be specified for future residential buildings, following the model of RVS 09.01.42 (Guidelines and Regulations for Road Construction):

• number of stories according to construction class • plus basement • each storey: 10 kN/m² floor load and 20 kN/m wall load (live loads included in these values)

4.3 Variable actions (on finished structure)

4.3.1 Traffic loads in the tunnel

The traffic loads on the tunnel invert have to be calculated according to the relevant standards.

4.3.2 Traffic loads above ground

Traffic loads have to be calculated according to the relevant standards. In case of an overburden of 3.50 m or more, the following simplified load assumptions, in analogy to RVS 09.01.42, are permissible, as consideration of a dynamic coefficient is no longer required:

• Road traffic and railways: substitute loads of 10 kN/m² on all possible traffic areas • Tramway: substitute loads of 5 kN/m² on all possible traffic areas

4.3.3 Pressure and suction load

Pressure and suction loading can be neglected in the design of the segmental lining system for road tunnels. In railway tunnels the aerodynamic loads calculated for the project in question have to be applied to all free surfaces, with due consideration of standard-compliant safety margins. In double-shell systems, pressure and suction loading of the segment system can be neglected.

4.3.4 Temperature influences

Design values for temperature differences and/or temperature gradients have to be determined on a project-specific basis for areas subject to major temperature differences due to climatic conditions, depth (geothermal gradient), use (water) or ventilation. In other areas, there is no need to consider temperature gradients and temperature differences.

4.3.5 Internal water pressure

The effect of internal water pressure and possible hydrodynamic loads are to be taken into consideration. The effective external water pressure (ground water pressure), the possible action of the surrounding rock mass and any pre-stress of the pre-cast lining relative to the surrounding rock must also be included in the calculation.

If the joints in unsealed segmental systems open under internal pressure, the relief effect due to pressure balance after the opening of the joints may be taken into consideration.

If the sealing function in sealed systems must be maintained also under internal pressure, the effectiveness of the sealing system is to be verified under internal pressure.

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4.4 Variable actions and combinations of actions during construction

4.4.1 Loading of segments from production to installation

The loads acting on the segments during de-moulding, handling, storage and transport to the site of installation have to be verified, taking account of the young age of the concrete.

4.4.2 Installation and thrust forces

The stresses and strains acting on the segment have to be verified.

Depending on the type of shield machine and the geological and hydro-geological conditions, the thrust forces acting on the segments may vary. When calculating the introduction of forces into the segments, the possibility of eccentric action of these forces, e.g. in curves, must be taken into consideration.

4.4.3 Support pressure and annulus grouting pressure

Depending on the construction method, the annular gap is grouted with mortar or slurry. The grouting pressure is to be determined as a function of the support pressure. The load from annular gap grouting on the rock is strongest at the time of grouting.

4.4.4 Rock load on the tunnel roof with partially bedded segment ring

If tunnelling machines without active face support are used, the annular gap can be filled with pea gravel or combinations of pea gravel and mortar and/or pea gravel and slurry in the crown and side wall areas. It should be borne in mind that the segment ring is not yet fully bedded when ejected from the shield and is likely to be loaded in partially bedded condition (e.g. blocks), see It. 4.2.2.

4.4.5 Uplift of the tunnel tube in grouting mortar

As a rule, this factor of influence is not to be taken into consideration; see Chapter 10 (Backfilling of the Annulus).

4.4.6 Loading of the invert area by back-up equipment of the TBM and logistic systems

In the invert area, construction-related loads, such as TBM back-up equipment, and transport loads are to be taken into account. Moreover, loading states from the installation of equipment in the tunnel, e.g. positioning of mass-spring systems, compaction of road structures, transport of machinery and equipment, have to be analysed.

4.4.7 Injection pressure due to post-injection and rock rehabilitation

Injection pressure due to post-injection has to be taken into consideration. Injections may impose isolated, uniform or asymmetrical actions. The maximum injection pressure must be determined according to the design specifications.

4.4.8 Buoyant forces due to concrete placement for the inner shell

Loads from the bracing forces of the formwork car during placement of the inner arch in the crown area are to be considered, if applicable.

4.5 Exceptional actions

4.5.1 Impact loads

According to TSI-SRT, the impact of a derailed train is not sufficient to impair the load-bearing capacity of the tunnel structure. Therefore, actions from impact loading do not have to be considered.

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4.5.2 Fire loads

The type and intensity of a potential fire load should be assessed on a project-specific basis. Fire loads are covered by the ÖVBB Guideline on “Increased Fire Protection with Concrete for Underground Traffic Structures” and by RVS 09.01.45.

4.5.3 Earthquake

As a rule, the influence of earthquake loads does not have to be considered in Austria.

4.5.4 Flooding of the tunnel tube

If flooding of the tunnel tube is possible, this action is to be considered.

4.5.5 Explosion

Depending on the types of hazardous goods allowed to be transported in the tunnel, Austrian Standard ÖNORM EN 1991-1-7 applies or project-specific requirements have to be specified.

4.5.6 Other disaster scenarios

Other disaster scenarios, if any, have to be considered on a project-specific basis.

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5 CALCULATION AND DESIGN OF SEGMENTS

5.1 General remarks

The design of the segmental lining in transverse and longitudinal direction has to comply with Austrian Standard ÖNORM EN 1992-1-1. The requirements in terms of both load-bearing capacity and serviceability have to be met. Special areas, such as intersections with crosscuts or niches, are to be analysed separately.

5.2 Calculation methods and models


The structural analysis is performed on the basis of representative design cross sections and/or stress and displacement fields.

5.2.2 Selection of the calculation method

As a rule, the Finite Element Method (FEM) or the Finite Difference Method (FDM) (two-dimensional or three-dimensional) is to be applied for the calculation of actions on the tunnel lining in loose rock and in solid rock classified as partly homogeneous. If rock mass behaviour is significantly determined by the properties of bedding planes and discontinuities, which usually applies to rock mass behaviour types BT1 “Stable” and BT2 “Stable with the potential of discontinuity-controlled block fall” according to the ÖGG Guideline for the Geo-mechanical Design of Underground Structures Excavated by Cyclic Driving”, the above calculation methods are not adequate. For these rock mass behaviour types, see Section 5.2.3. For high overburdens in solid rock, the convergence confinement method may also be used for the calculation of actions.

The stress resultants of the tunnel lining can also be determined by the model of an elastically bedded beam. Three-dimensional systems are only recommended for areas of intersection between crosscuts and the main tunnel. For a continuous linear structure without sudden changes in cross section or concentrated load flows, a two-dimensional approach is sufficient.

5.2.3 Calculation methods for rock masses with bedding planes and discontinuities

If the characteristics of the rock mass are significantly influenced by the properties of bedding planes and discontinuities, in particular for rock mass behaviour types BT1 “Stable” and BT2 “Stable with the potential of discontinuity-controlled block fall” according to the ÖGG Guideline for the Geo-mechanical Design of Underground Structures Excavated by Cyclic Driving”, the potential of gravity-induced falling and sliding of blocks from the excavated cross section is to be investigated by means of appropriate programmes (e.g. Block Stability Programme) or by geometric models replicating the geometry and the essential properties of joints and bedding planes at least in qualitative terms. The rock between discontinuities can be regarded as rigid. The actions are determined on the basis of the volume of the relevant blocks.

5.2.4 Calculation of the tunnel shell

5.2.4.1 Calculation by means of FEM or FDM

In calculation methods based on a two-dimensional approach (e.g. two-dimensional FEM), stress relief ahead of the tunnel face can be assumed [1].

The fields to be analysed have to be chosen in such a way that the influence of the cavity has subsided at the edges of the field. (Recommendations of Working Group 1.6 “Numerical Design Methods in Geo-engineering” Section 2 [2]). Support of the edges is linear (see Fig. 5-1).

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To determine the stress resultants in the tunnel shell, the shell can be simulated together with the numerical model of the surrounding rock mass and/or ground by means of shell or beam elements and elastic constitutive laws.

The advantage of a three-dimensional model is due to the fact that it eliminates the need for an advance estimate of the longitudinal load-bearing effect and the stress relief of the rock mass ahead of the working face.

5.2.4.2 Determination of stress resultants by the bedded beam model

If a bedded beam is used, the actions determined by means of FDM, FEM or the convergence confinement method can be applied to the bedded beam.

In the bedded beam model, the distribution of the spring elements over the circumference is determined by the properties of the ground to be cut through. Subject to the elimination of compressive forces, radial bedding can be calculated either as constant along the circumference or variable over the lateral surface depending on the ground. The bedding modulus can be approximated as kr = Es/R, with Es

As a matter of principle, tensile springs or tensile stresses are to be excluded for the bedding. Tangential bedding of the tunnel lining may be assumed in order to stabilise the computation [3].

being the stiffness modulus and R the outer radius of the segmental lining.

5.2.5 Stiffness of the segment ring

The influence of articulation in the radial joints (see Joints, It. 5.2.6) must be realistically incorporated into the calculation, as it diminishes the stiffness of the segment ring. Keystones of a size < 20 % of the circumference of a standard segment need not be considered in detail in the structural system and the design model.

For pre-design purposes or for the calculation of actions on the tunnel shell by means of FEM or FDM, the reduction in stiffness of a segment ring consisting of several segments can be considered via a reduced moment of inertia [4]:

2

.4

∗+=

mIII NSabg

Iabg.

Ireduced moment of inertia of the segment

S

I moment of inertia of the force transmission area

N

m number of segments must be > 4 (keystones of a size < 20 % of circumference not to be counted)

moment of inertia of the standard cross section

Fig. 5-1 Calculation model

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5.2.6 Structural consideration of radial joints

In the detailed determination of stress resultants, the reduced stiffness of the radial joints is taken into account via non-linear torsion springs and/or an active hinge.

For additional references to different types of joints, see Chapter 7.

5.2.6.1 Flat joints

The non-linear behaviour of radial segment joints is to be considered in the calculations for straight joints via non-linear torsions springs according to Prof. Leonhardt/Reichmann “Concrete Hinges” [5]. The findings described in these papers were confirmed by large-scale tests in the 4th

The torsional stiffness depends, inter alia, on the normal force acting on the ring, the joint width, the eccentricity of the normal force and the resulting joint gaping.

tube of the Elbe Tunnel [6].

The torsional stiffness of an over-compressed joint, assuming a contact area width b and a contact area length of 1 m, is calculated as follows:

]/.[12

2

radmkNbEC cmD

⋅=

with the contact area width b in m (see Fig. 5/2) and the modulus of elasticity Ecm according to Austrian Standard ÖNORM EN 1992-1-1 in kN/m2

][2 radbE

Ncm ⋅⋅

≤α

. For the over-compressed joint the angle α in rad is calculated with the following equation [7]:

If there is a gap in the joint, the stress curve and the deformation are as shown in the following diagram (see Fig 5/2):

Fig. 5-2 Stress curve with gaping joint

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The stiffness of the torsion spring is calculated for a length of contact area of 1 m, assuming a gaping joint:

]/.[18 0

3

3

radmkNE

bNCD ⋅⋅=

α

N normal force [kN/m]

α torsion angle [rad]

E0

An approximation of this modulus of elasticity can be calculated according to DAfStb (German Reinforced Concrete Committee), Issue 175 [5] with

modulus of elasticity of concrete as tangent modulus with σ = ε = 0.

10180000000

wE β⋅= in kN/m².

wβ here corresponding to the mean cube strength (20 cm edge length). The conversion of cube strength determined on a 15 cm cube, according to Austrian Standard ÖNORM EN 1992-1-1, is possible with cmcmw f 15,95,0 ⋅=β . In case of strong torsion, the moment does not increase linearly. This usually leads to overstraining of the joint. For the calculation of such a hinge-type system, the M-α relation according to [7] can be considered through a bilinear approximation for torsional stiffness according to Fig. 5/3. The torsional stiffness in the first part up to

5,30 =⋅⋅

NEbα

is equal to the initial stiffness of the over-compressed cross section; beyond that part, it is to be considered with 1% of the initial stiffness.

5.2.6.2 Curved joints (rolling contact joints)

In the case of continuous radial joints parallel to the ring axis, curved joints are to be considered as active hinges. In the case of staggered radial joints and radial joints not parallel to the ring axis, the stiffness of curved joints is to be taken into account.

Fig. 5-3 Moment-torsion-angle diagram, dimensionless

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5.2.7 Tolerances and imperfections

The relevant combination of joint offset and angular torsion at the segment ring as well as the tolerances according to Chapter 11 and the imperfections according to Chapter 12 are to be allowed for in the design.

5.3 Combination of actions, design situations and partial safety factors

As a rule, partial safety factors have to applied for permanent and temporary and/or exceptional design situations according to Austrian Standard ÖNORM EN 1992-1-1.

Special rules apply to the following combinations of actions and/or construction states:

• For the combination of actions “Rock load on the tunnel roof with partially bedded segment ring”, see It. 4.4.4., a partial safety factor of γF

• If the actual and/or required thrust of the TBM is known precisely, the partial safety factor of the action applied to determine its design value can be reduced from that given in Austrian Standard ÖNORM EN 1992-1-1. In this case, the design value of the action can be determined with a partial safety factor of γ

= 1.0 is to be applied. (Partial safety factors for resistance remain unchanged.)

F

• For the combination of actions “System-limited maximum internal water pressure”, see Definitions, a partial safety factor of γF = 1.0 is to be applied. (Partial safety factors for resistance remain unchanged.)

= 1.2 and the maximum installed thrust. (Partial safety factors for resistance remain unchanged.)

5.4 Verification of load-bearing capacity


The load-bearing capacity has to be verified according to Austrian Standard ÖNORM EN 1992-1-1 for slab structures.

If the percentage of dynamic actions is low (< 30% of permanent actions), the use of welded reinforcement mesh is permitted.

The design rules for fibre-reinforced concrete and fibre-reinforced concrete with conventional reinforcement are laid down in the ÖVBB Guideline on “Fibre-Reinforced Concrete”.

To prevent brittle fracture, the minimum reinforcement according to Austrian Standard ÖNORM EN 1992-1-1 is to be provided for to cover all load cases during production and installation. Reduction of the minimum reinforcement to 0.1%, in analogy with RVS 09.01.42, is permitted in the longitudinal direction of the tunnel.

In agreement with the Owner, the minimum reinforcement may be reduced from that given in Austrian Standard ÖNORM EN 1992-1-1 to the structurally required amount, if quality and safety management during production, transport and installation can ensure that no load cases other than those verified will occur. Condition II (cracked concrete) is to be used as a basis for this calculation. As regards the final state (structure in use), the provisions of Austrian Standard ÖNORM EN 1992-1-1 apply, with due consideration given to the permanent normal forces in the segment. Segments without the minimum reinforcement according to EU 1992-1-1 are regarded as non-reinforced or lightly reinforced structural components.

Tensile splitting forces in the segments, caused by thrust jacks and normal forces, have to be verified according to Austrian Standard ÖNORM EN 1992-1-1. The use of welded ladder stirrups is permitted.

Compression of contact areas in the radial and circumferential joints it to be verified. In the case of curved joints, the size of the contact area can be determined by means of Hertz’s compression or according to Janßen [7] or through testing. Stress induced by limited contact areas has to be verified according to Austrian Standard ÖNORM EN 1992-1-1.

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5.4.2 Design of radial and circumferential joints

In the design of radial joints, special attention is to be paid to the following: • Type and amount of effective internal forces to be transmitted (M, N, Q) • Amount and mode of action of the forces of the joint gasket to be transmitted • Amount and mode of action of forces from kinematic constraints to be transmitted • Efficiency and geometric allocation of forces to be transmitted through limited contact areas • Effects, if any, of segment production tolerances • Kinematics and imperfections or installation tolerances (ovality and joint misalignment) of the

segment ring In the design of circumferential joints, special attention is to be paid to the following: • Distribution, location and type of load introduction of thrust and steering forces as well as

efficiency and geometric allocation of forces to be transmitted through limited contact areas • Amount and mode of action of sealing system forces to be transmitted • Effects, if any, of segment production tolerances • Amount and mode of action of possible load introductions via centring aids and/or connecting

devices related to the kinematics and imperfections or installation tolerances (ovality and joint offset) of the segment ring

For details on the individual types of joints, see Chapter 7.

5.4.3 Coupling forces

There is a strong international trend to dispense with structurally effective coupling elements (tongue-and-groove, cam-and-socket couplings) or to minimise their dimensions (cam-and-socket coupling see Chapter 7). As a rule, computational verification is not required for couplings with a usual slip of > 5 mm [8], provided that grouting of the annular gap is complete and performed under constant pressure. Additional reserves to prevent mutual displacement of the segment rings in the radial joint are provided by the shear strength of the backfill material in the annulus and the activation of friction forces in the circumferential joint. For the combination of actions “Rock load in the tunnel roof area with partially bedded segment ring” and certain exceptional actions (e.g. flooding), the need for structurally effective coupling is to be verified.

5.4.4 Indications for fire design

For fire design, the provisions of RVS 09.01.45 (Road) or the ÖVBB Guideline on “Increased Fire Protection with Concrete for Underground Traffic Structures” are to be observed.

In a double-shell system with a fire protection lining, the interaction between the inner and outer lining in case of fire is to be taken into consideration for fire design. Special attention is to be paid to the following: • possible temperature transition between inner and outer lining • expansion of the fire protection lining and resulting load on the outer lining • slip due to possible presence of non-wovens between inner and outer lining • support of the fire protection lining

5.5 Verification of serviceability


Serviceability is to be verified in accordance with Austrian Standard ÖNORM EN 1992-1-1. Verification of serviceability of fibre-reinforced concrete and fibre-reinforced concrete with conventional reinforcement is dealt with in the ÖVBB Guideline on “Fibre-Reinforced Concrete”.

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5.5.2 Limitation of crack width

The limitation of crack widths is to be verified for the segmental system under load. Crack widths are to be determined for the tightness classes according to Table 3/1 (waterproofing requirements) or on a project-specific basis.

5.5.3 Limitation of deformations

The tolerability of ring deformation and its impact on gasket frames and bolt connections in the area of radial and circumferential joints is to be analysed, if waterproofing of the tunnel lining is required.

As regards the limits of deformation for the entire ovalisation of the cross section, see Chapter 12 on Imperfections.

5.6 Structural design of segments

The rules of Austrian Standard ÖNORM EN 1992-1-1 apply. For joint design, see Chapter 7.

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6 CONCRETE

6.1 General remarks

Subject to compliance with the required concrete properties, optimisation of the concrete used results in a higher segment production capacity and ensures the necessary quality of the pre-cast concrete parts. However, given the need for heat treatment of the concrete (see Item 8.1.4) as a prerequisite for high-quality segment production, output can only be increased within certain limits. As a matter of principle, segments are made from concrete according to Austrian Standard ÖNORM B 4710-1.

6.2 Requirements

The requirements to be met by the concrete are defined in terms of strength classes, exposure classes and – depending on the production method – strength development during the first hours. Besides the requirements to be met by concrete as a building material, the segment surface also has to meet certain quality criteria (see Item 6.2.6).

6.2.1 Strength classification

The strength class of the concrete is defined in terms of minimum compressive strength according to Austrian Standard ÖNORM B 4710-1, which is to be verified at a specified point in time. Depending on the method of segment production, high early strength is usually required. As a rule, this means that the minimum compressive strength is significantly exceeded. This can be allowed for either by specifying a high strength class (e.g. C40/50) or by limiting the maximum permissible compressive strength at the specified point in time. According to Austrian Standard ÖNORM B 4710-1, it can be taken for granted that the concrete, if appropriately worked and post-treated, meets the required properties, as verified through conformity testing, also in the structural component. However, conformity testing usually only covers the building material, i.e. the concrete produced, but not the structural component. It is important to bear in mind that storage conditions in the case of heat treatment are different from storage according to Austrian Standard ÖNORM B 3303. Strength testing therefore has to be performed on samples subject to the type of (heat) storage required for the production method chosen. Steel is to be used as formwork material for the test specimens. If strength testing is to be performed on the finished segment, the results are to be evaluated according to Austrian Standard ÖNORM B 4710-1. Testing on the basis of Austrian Standard ÖNORM EN 13791 is only permitted if agreed upon through a special provision in the contract.

6.2.2 Exposure classification

If segments are produced without heat treatment and the maximum temperature of the structural component demonstrably does not exceed 55°C, verification of exposure classes according to Austrian Standard ÖNORM B 4710-1 NAD 10 is permitted. If this is not the case, testing for exposure classes XC3, XC4, XF and XM must be performed on hardened concrete according to Austrian Standard ÖNORM B 3303. It is important to bear in mind that storage conditions in the case of heat treatment are different from storage according to Austrian Standard ÖNORM B 3303. Testing for exposure classes therefore has to be performed on samples subject to the type of (heat) storage required for the production method chosen. Steel is to be used as formwork material for the test specimens. The frequency of testing within the framework of conformity testing and identity testing is to be specified by the design engineer. In the absence of a specified test frequency, the test frequencies indicated in It. 6.4 apply. For exposure class XA2, a water penetration depth of < 25 mm in hardened concrete has to be demonstrated, in addition to the fresh concrete parameters. To ensure corrosion protection of the reinforcement, concrete for reinforced segments, regardless of the designated concrete class, must always meet at least exposure class XC2.

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6.2.3 Early strength

Depending on the production method, a very high level of strength may be required in young concrete (usually 6 – 8 hours) to absorb actions such as deadweight and transport loads. The design engineer has to specify the required uniaxial tensile strength at the time of de-moulding (usually between 0.8 and 1.2 N/mm²). As a rule, this is verified indirectly through compressive strength testing. Within the framework of pre-construction testing, a correlation between tensile strength and compressive strength at the time of de-moulding is to be established.

6.2.4 Maximum grain size

The design engineer has to specify the maximum grain size of the concrete, considering the dimensions of the structural component, the amount of reinforcement, the cover to reinforcement and the workability of the concrete.

6.2.5 Consistency

Workability of the concrete is essential in segment production. Given the fact that workability is related to the production method chosen, the required consistency cannot be specified by the design engineer. As a rule, the designation of the concrete grade therefore does not contain a reference to the consistency class. (Deviating from Austrian Standard ÖNORM B 4710-1, F45 does not apply in the absence of a specified consistency class). The required consistency is to be established within the framework of pre-construction testing and during production of the test segments.

If the segment production method chosen demands a stiff concrete consistency, consistency class C2 is sufficient for the pre-construction test. Within the framework of mix optimisation during production of the test segments, adjustment of consistency to the next higher or lower consistency class is permitted. If consistency differs from the class used in pre-construction testing by more than one consistency class, pre-construction testing has to be repeated. The scope of the repeated pre-construction test is to be determined by the competent external inspection body.

6.2.6 Surface characteristics

6.2.6.1 General remarks

Depending on the segmental system, it may be appropriate to differentiate between the concrete surfaces on the mountain side, the cavity side and in the joint areas. The porosity and structure of the segment surface can be defined according to the ÖVBB Guideline on “Fair-Faced Concrete – Formed Concrete Surfaces” or on the basis of special, clearly defined criteria. The required surface characteristics on the mountain side of the segment are determined, inter alia, by the following factors: • Durability in the presence of chemical attack • Effect on mechanical lifting devices • Dimensional accuracy requirements and tolerances (Chapter 11) • Type of tailskin seal The required surface characteristics on the tunnel side of the segment are determined, inter alia, by the following factors: • Durability in the presence of chemical or de-icing salt attack • Risk of cavitation in water tunnels • Waterproofing requirements • Requirements to be met by the segment surface as a base for paint coats and/or other coatings • Effect on mechanical lifting devices • Dimensional accuracy requirements and tolerances (Chapter 11)

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The required surface characteristics of the joint areas of the segment are determined, inter alia, by the following factors: • Durability in the presence of chemical or de-icing salt attack • Risk of cavitation in water tunnels • Waterproofing requirements • Dimensional accuracy requirements and tolerances (Chapter 11) If very stiff concrete is used, the formwork may not be filled properly and nest formation may occur, especially in corners. To avoid nest formation in corners, it is advisable to use appropriately sized vibrators or to adjust the concrete consistency. Poorly maintained formwork or formwork seals may also result in a loss of cement slurry and nest formation.

6.2.6.2 Blowhole formation

The risk of air being entrapped near the concrete surface is particularly acute if forms for segment production are used in horizontal position, as blowholes at the formwork skin tend to form in formwork parts that are only slightly inclined.

The maximum number of blowholes per unit of surface area is to be limited, as segments are lifted by means of a vacuum device and proper sealing at the tailskin must be ensured. The maximum depth of blowholes must not exceed 10 mm.

As regards surfaces to which waterproofing is to be applied, Items 7.2, 8.1.6 and 9.5.8.2 as well as Chapter 11 apply.

As regards the cover to reinforcement, Items 8.1.3 and 9.5.1.6 apply.

6.2.6.3 Evenness

In the formwork filling area inadmissible deviations from the required measure of evenness may occur, if stiff concrete is poorly struck off manually or if soft concrete is dented on the surface during the downstream production process (for re-working, see also Item 8.1.4).

The allowable tolerances according to Chapter 11 must be taken into consideration.

6.2.6.4 Texture

If required, the texture is to be specified according to the qualify criteria of the ÖVBB Guideline on “Fair-Faced Concrete – Formed Concrete Surfaces”, Table 5/5/2. The tolerances according to Chapter 11 must be met.

6.3 Constituent materials of concrete

6.3.1 Cement

Cement has to meet all the requirements of Austrian Standard ÖNORM EN 197-1 and the requirements of Austrian Standard ÖNORM B 3327-1 for class WT42, except for the temperature class.

6.3.2 Mineral aggregates

Mineral aggregates have to meet the requirements of Austrian Standards ÖNORM EN 12620 and ÖNORM B 3131. Aggregate grading class SK1 and frost class F1 must be complied with. An assessment of the alkali aggregate reaction according to Austrian Standard ÖNORM B 3100 is only required for aggregates with an AAR potential that are used in combination with cement with a total alkali content of > 0.6%.

6.3.3 Water

Austrian Standard ÖNORM B 4710-1 applies to mixing water. As regards the assessment of mixing water, the limits specified in Austrian Standard ÖNORM EN 1008 apply.

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6.3.4 Additives

The only additives to be used are silica dust according to Austrian Standards ÖNORM EN 13263-1 and ÖNORM EN 13263-2 or prepared hydraulically active additives (AHWZ) according to Austrian Standard ÖNORM B 3309. Application of the k-value concept according to Austrian Standard ÖNORM B 4710-1 is permitted for these additives.

6.3.5 Admixtures

All admixtures have to meet the requirements of Austrian Standard ÖNORM EN 934-2. If several admixtures are used together, their compatibility according to Austrian Standard ÖNORM B 4710-1 has to be verified.

6.3.6 Fibres

Fibres must comply with the ÖVBB Guideline on “Fibre-Reinforced Concrete” and/or the ÖVBB Guideline on “Increased Fire Protection with Concrete for Underground Traffic Structures”, Item 6.1.

6.4 Testing

Pre-construction, conformity and identity tests are to be performed according to Austrian Standards ÖNORM B 4710-1 and ÖNORM EN 13369. If fibres are used, the ÖVBB Guideline on “Fibre-Reinforced Concrete” applies. For fire-resistant concrete, the ÖVBB Guideline on “Increased Fire Protection with Concrete for Underground Traffic Structures” is to be taken into account. Deviating from and/or in addition to the above standards and/or ÖVBB Guidelines, the provisions specified in the following apply.

6.4.1 Pre-construction testing

Pre-construction testing serves to verify that all requirements are met with the constituent materials and additives (e.g. fibres) used, with due consideration given to any intended heat treatment programme. If plastic fibres are used to increase fire resistance, a heat treatment programme is provided for or the temperature of the structural component exceeds 55°C, verification of exposure classes has to be performed in hardened concrete (see It. 6.2.2).

Prior to the beginning of mass production, test segments are to be produced from the concrete mix established through pre-construction testing, using the plant and equipment as well as the moulds intended for actual production. In this stage of the procedure the required consistency of the concrete is determined. The test segments are used to verify if the structural component, the built-in parts and the concrete surface are within the required tolerances. All documents according to Table 6/1 are to be summarised in a pre-construction test report on segment production. If a heat treatment programme is provided for, the required pre-storage time is to be indicated.

The parameters required for quality control of the concrete are to be entered as target values in Form 1 of Austrian Standard ÖNORM B 4710-1.

In the event of any changes in the concrete composition, the constituent materials or the production process, or any other changes that may significantly modify the product properties, the pre-construction test is to be repeated. The need for repeat testing is to be established by the external inspection body.

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Subject of testing Standard, Guideline Indication obligatory

If required

Concrete mixing plant with micro-processor control ÖN B 4710-1 X -

Suitability of constituent materials of concrete It. 6.3 X - Reinforcement, built-in parts, fastenings - X - Fresh concrete Consistency ÖN B 3303 Sect. 6.1 X - Air content ÖN B 3303 Sect. 6.3 - X Total water content ÖN B 3303 Sect. 6.4 X - W/B value ÖN B 3303 Sect. 6.6 X - Bulk density ÖN B 3303 Sect. 7.1 X - Fibre content and fibre distribution (PP fibres) ÖVBB Guideline Annex

4 - (1) X

Fibre content and fibre distribution (steel fibres) ÖVBB Guideline It. 10.3 - (2) X

Hardened concrete Compressive strength at7d, 28d and at specified point in time

*)

ÖN B 3303 Sect. 7.2 X -

Flexural tensile strength at specified point in time ÖN B 3303 Sect. 7.3 X -

Verification of exposure class depending on requirements (see It. 6.2.2) ÖN B 3303 Sect. 7 - X

Verification L300 ÖN B 3303 Sect. 7.6 (for XF1 or XF3) - X Verification L300 ÖN B 3303 Sect. 7.6 AF (for XF2 or XF4) - X Modulus of elasticity ÖN B 3303 Sect. 7.7 - X Temperature increase in concrete without heat treatment (if no heat treatment is performed) ÖN B 3303 Sect. 7.17 - X

Temperature increase in concrete with heat treatment - X -

Fibre-reinforced concrete class ÖVBB Guideline - (2) X Segment Compressive strength after 28d and/or at specified point in time ÖN B 3303 Sect. 7.2 **) X -

Surface characteristics It. 6.2.6 X - Stripping and lift-off strength It. 6.2.3 X - Production tolerances of segment by segment type Chapter 11 X -

Tolerances of assembly parts by segment type Chapter 11 - X Acceptance of reinforcement - X - Concrete cover on segment in 40 cm grid, by segment type - X -

Graphic representation of temperature development over min. 72 hours at 3 different measuring points in core area, surface and air temperature to evaluate limit parameters according to It. 8.1.4, temperature indication: minimum, mean, maximum

It. 8.1.4 X -

*) The test specimens are to be made from fresh concrete and have to be post-treated and stored for 24 hours under factory conditions corresponding, as much as possible, to on-site conditions for the product.

**) Evaluation of the relationship between the strength of the structural component determined indirectly by means of the rebound tester and the compressive strength of the test cube through indication of conversion factors.

(1) ÖVBB Guideline “Increased Fire Protection with Concrete for Underground Traffic Structures” (2) ÖVBB Guideline “Fibre-Reinforced Concrete” Note: Example of specified point in time: lift-off time

Table 6/1 Scope of pre-construction testing (footnotes also apply to Tables 6/2 and 6/3)

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6.4.2 Conformity testing

Continuous monitoring of production control (regular production control) is performed by an accredited inspection body (third-party inspection) according to Austrian Standard ÖNORM EN 13369.

The requirements for the assessment of conformity through continuous factory production control (own control) are laid down in Table 6/2. The results of factory production control must be documented and have to be reviewed and certified by the external inspection body. All quality-relevant documents must be made available to the user of the segments.

Parameter Standard Test Test frequency Constituent materials of concrete ÖN B 4710-1 It. 9.9, Tab. 22 It. 9.9, Tab. 22 Fresh concrete Delivery note ÖN B 4710-1 It. 7.3 every delivery Fresh concrete temperature 1 x daily

Consistency ÖN B 3303 Sect. 6.1 every 50th

Air content

segment, but min. 1 x daily

ÖN B 3303 Sect. 6.3 min. 1 x daily (if required) Bulk density ÖN B 3303 Sect. 7.1 min. 1 x daily Total water content ÖN B 3303 Sect. 6.4 1 x weekly

Fibre content and fibre distribution (plastic fibres)

ÖVBB Guideline Annex 4 (1)

up to 1000 segments 1 x every 250 segments, then min. 1 x every 500 segments

Fibre content and fibre distribution (steel fibres)

ÖVBB Guideline It. 10.3 (2)

up to 1000 segments 1 x every 250 segments, then min. 1 x every 500 segments

Hardened concrete

Compressive strength (7d, 28d and/or at specified point in time)

*)

ÖN B 3303 Sect. 7.2 up to 1000 segments 1 x every 100 segments, then 1 x every 200 segments

Verification of exposure class by application (see It. 6.2.2) ÖN B 3303 Sect. 7

for every 500 segments min. 1 x Verification L300 ÖN B 3303 (for XF3) Sect. 7.6

Verification L300 ÖN B 3303 and AF (for XF4) Sect. 7.6 Segment Concrete compressive strength (indirect method – rebound tester) ÖN B 3303 Sect. 8 for every 100 segments

min. 1 x Temperature development over 72 hours at 3 different measuring points in core area, surface temperature, air temperature

It. 8.1.4

by segment geometry: one in 20 segments up to 100 segments, then one in 200 segments

Acceptance of reinforcement It. 8.1.3 every segment Concrete cover at min. 10 points evenly distributed over the segment, by segment type

one in 10 segments up to 100 segments, then one in 500 segments

Evaluation for surface characteristics and blowholes It. 6.2.6 every segment

(1) ÖVBB Guideline “Increased Fire Protection with Concrete for Underground Traffic Structures” (2) ÖVBB Guideline “Fibre-Reinforced Concrete”

Table 6/2 Scope of conformity testing (footnotes in Table 6/1 apply)

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6.4.3 Identity testing

The identity test is to be performed by an accredited inspection body on behalf of the client; the entire documentation of the concrete producer relating to pre-construction and conformity testing must be made available to the inspection body and the Owner/design engineer. If the segment producer is not identical with the concrete producer, the segment producer is obliged to perform identity tests in addition to the identity tests performed by the Owner/design engineer.

Parameter Standard Test Test frequency General tests Conformity test performed by producer according to It. 6.4.2 for plausibility

Retroactively covering the period since last identity test

Reinforcement mesh in open formwork 1 x in 500 segments

Fresh concrete Fresh concrete temperature

1 x in 500 segments Consistency ÖN B 3303 Sect. 6.1 Air content ÖN B 3303 Sect. 6.3 Bulk density ÖN B 3303 Sect. 7.1 Total water content ÖN B 3303 Sect. 6.4 Fibre content and fibre distribution (PP fibres)

ÖVBB Guideline Annex 4 (1) 1 x in 1000 segments

Fibre content and fibre distribution (steel fibres)

ÖVBB Guideline It. 10.3 (2) 1 x in 1000 segments

Hardened concrete Compressive strength (7 d, 28 d, and/or at specified point in time)

*)

ÖN B 3303 Sect. 7.2 1 x in 500 segments

Verification of exposure class in hardened concrete, by requirements It. 6.2.2 1 x in 1000 segments

Segment Indirect concrete compressive strength (rebound tester) ÖN B 3303 Sect.8 1 x in 50 segments

Concrete cover at min. 10 relevant points for each segment type 1 x in 1000 segments

Evaluation for surface characteristics and blowholes It. 6.2.6 1 x in 1000 segments

* The test specimens are to be made from fresh concrete and have to be post-treated and stored for 24 hours under

factory conditions corresponding, as much as possible, to on-site conditions for the product.

Table 6/3 Scope of identity testing (footnotes of Table 6/1 apply)

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7 JOINT DESIGN

7.1 Types of joints and their structural design

7.1.1 Radial joints

Function of and stress on radial joints:

Radial joints essentially serve to close the load-bearing segment ring and, if required, hold a segment gasket. They transmit the internal forces (M, N, Q) of the structural system of the segment ring and/or the segment shell resulting from external and internal loads as well as the prestress forces required to obtain the sealing effect.

Structural design of radial joints:

As regards the structural design of radial joints, special attention must be paid to the following:

• Concentration of load-transferring contact in areas that can be covered by structural reinforcement.

• Stress relief for areas (corners and edges) that cannot be covered by structural reinforcement through appropriate geometric shapes (setbacks).

• Avoidance of notches and notch effects in the load-transferring joint area. • If possible, centric arrangement of load-transferring joint areas. • Sufficient gaps between the gasket and the flanks of the groove to ensure safe introduction of

prestress forces. • Consideration of production and installation tolerances, depending on specific requirements.

7.1.2 Circumferential joints

Function of and stress on circumferential joints:

The circumferential joints essentially serve to transfer longitudinal thrust forces, coupling forces and steering forces and, if required, to hold a segment gasket. Moreover, the circumferential joint also serves to translate alignment corrections and/or curves of the TBM, which may result in unequal load introduction and – in the case of alignment corrections made by means of packers – stress induced through limited contact areas.

Structural design of circumferential joints:

In the structural design of circumferential joints, special attention must be paid to the following:


• Consideration of compatibility between centring aids and/or connectors and joint kinematics. • Sufficient gaps between the gasket and the flanks of the groove to ensure safe introduction of

the prestress forces in order to obtain a tight joint. • Compliance with production and installation tolerances, depending on specific requirements,

with special consideration given to alignment corrections. • Circumferential joint geometry considering joint inserts and joint inlays and their

compressibility.

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7.1.3 Shapes of joints

7.1.3.1 Completely flat joints

Design features of completely flat joints:

• Flat joint (usually a circumferential joint), possibly with gasket groove and/or bevelled edges. • Stress relief for areas (corners and edges) that cannot be covered by structural reinforcement

through appropriate geometric shapes (setbacks). • Designing completely flat joints: • Generally non-loaded or temporarily loaded joints. • Design for eccentric load introduction with asymmetric load distribution (effect of moments) in

a load-transferring radial joint. • Design for introduction of press forces through limited contact areas, as well as stress induced

through limited contact areas due to packers in a circumferential joint. • If appropriate, design for introduction of forces from segment gasket.

7.1.3.2 Partially flat joints

Design features of partially flat joints:

• Structural arrangement of a plane, centrally positioned load transfer area that can be covered by reinforcement.


• If combined with one or several gasket grooves, centric positioning of load transfer area is advisable.

• Designing partially flat joints: • Special consideration is to be given to a possible additional moment from joint kinematics due

to planeness. 7.1.3.3 Curved joints

Design features of curved joints:

• Structural arrangement of a load transfer area with radius R, arched in the direction of the joint, which supports central load transfer through the mutual joint geometry and can be covered by structural reinforcement (primarily radial joint).

• Concave/convex joints: Rkonkav/Rkonvex

• High-load joint concave/convex: R ≈ 1.2 × segment thickness

konvex

• High-load joint convex/convex: R ≈ 1.0 × segment thickness

konvex

• Self-centring curved joint concave/convex: R ≈ 5–10 × segment thickness

konvex


≈ 0.5 × segment thickness

• If combined with one or several gasket grooves (high-load joint convex/convex), central positioning of the load transfer area is advisable.

Designing curved joints (see also It. 5.4.1):

• Verification of stress induced through limited contact areas • Consideration of imperfections (ovalisation, joint misalignment) • Consideration of superposition of internal forces of the ring and forces from the segment gasket

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7.1.3.4 Coupling joints

Mechanical coupling can be achieved through a tongue-groove system (Fig. 7/1) in circumferential and radial joints and/or a cam-socket system (Fig. 7/2) in circumferential joints.

Cam-and-socket and/or tongue-and-groove connections are to be designed with the plane of weakness in the cam and/or tongue; thus, the tightness of the segmental lining remains intact in case of damage. The clearance between the cam and socket and/or the tongue and groove should be greater than or equal to the installation tolerance. To avoid notch stresses, cavettos should be rounded rather than sharp-edged. To protect the flanks of coupling elements from damage during installation, a layer of plastic material, e.g. Kaubit strips, is to be inserted. The reinforcement is to be designed so as to protect the cam and/or groove flanks.

The coupling systems can be designed to cover catastrophic scenarios. For curved joints the design indications of It. 7.1.3.3 apply.

7.1.4 Keystone joint

Structural design – wedge-shaped keystone • The above references to radial joints apply. • Taper 8–11° for trapezoidal and rhomboidal shapes • Taper 17–21° for hexagonal shapes • Stress relief for load-bearing areas (corners and edges) that cannot be covered by structural

reinforcement through appropriate geometric shapes (setbacks). • Free choice of joint shapes • Sliding back of the wedge-shaped keystone during installation of the ring can be prevented

through appropriate choice and arrangement of connectors. • Positive locking is important to prevent “slip-through”. • Structural design – keystone with parallel radial joint: • The above references to radial joints apply. • Free choice of joint shapes, completely flat joints should be avoided.

Fig. 7-1 Tongue and groove joint system Fig. 7-2 Cam and socket joint system

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• Positive locking is important to avoid “slip-through”. Designing keystone joints: • The usual design indications apply to keystone joints.

7.2 Joint sealing systems

7.2.1 Systems with unsealed joints

Waterproofing of the segment ring is not provided for (AT4

Depending on project-specific requirements, the joints have to be designed to ensure permanent discharge of ground water entering the tunnel structure.

according to Tab. 3/1). Joint sealing is only required to reliably prevent a loss of segment bedding.

7.2.2 Systems with mortar-filled joints (combined with injection)

Basically, conditions are the same as for unsealed joints. However, by filling the joint with mortar it is possible to create the prerequisites for contact grouting of the annulus and, if necessary, injection of the surrounding rock (Fig. 7-3 and Fig. 7-4).

The shape of the joint must such as to allow the filling material to penetrate to a depth that ensures sufficient bonding of the mortar or to create conditions of positive locking. The groove of the mortar-filled joint must not interfere with the structurally relevant load transfer width of the radial joint. Low-shrinkage mortar and a suitable degree of stiffness are essential.

7.2.3 Systems with waterproof lining

The tightness of the structure is guaranteed by the individual components of the support system, consisting of the segments and the segment gasket. The individual elements of the support system have to be adapted to each other. Gaskets positioned around the individual segment like a frame ensure the tightness of the joint. If high waterproofing requirements have to be met, a double gasket frame can be used, with webs between the individual frames arranged in such a way as to prevent water from flowing along the joint between the sealing frames. As a rule, T-bar joints in the segment lining are to be avoided for AT1 and AT2. Elastomer gaskets are placed along the joint flanks of the segment and held in the groove by means of adhesive or concreted. Elastically compressible gaskets are used most frequently, whereas swellseal strips are rarely applied. It is also possible to combine both systems, with the swellseal strip integrated into the elastomer gasket.

7.2.3.1 Gasket groove

The all-round groove holds the gasket in place during installation and enables it to resist the prevailing water pressure in the finished structure. It has to be adjusted to the shape of the gasket. It must be positioned far enough from the outer edge of the segment to prevent spalling of the concrete at the groove flanks under the recovery forces of the compressed gasket. Computational verification is required to show that spalling will not occur, especially at the corners of the frame.

Fig. 7-3 Example of mortar-filled curved joint Fig. 7-4 Example of mortar-filled flat joint

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The base and the flanks of the grooves must be even and free of visible blowholes. For waterproofing requirements classes AT1 to AT2 it may be necessary to seal the base and the flanks of the groove (e.g. by means of epoxide resin).

7.2.3.2 Swellseal strips

Swellseal strips can be used in the presence of low water pressure, but must never dry out completely. The suitability of swellseal strips, depending on the chemical properties of the ground water, must be demonstrated through testing. Early swelling of the seal is to be prevented. The use of swellseal strips is only permitted for requirements class AT3.

7.2.3.3 Elastomer gaskets

For structures with high waterproofing requirements (requirements classes AT1 and AT2) closed-cell elastomer gaskets are used most frequently. The gasket strips are glued into the groove at a defined pre-stress of ca. 1% to 3%. The gasket is to be chosen according to the required durability (relaxation), the specified safety margin, the permissible installation tolerances and the prevailing water pressure. Tightness of the gasket is to be demonstrated through testing. The ratio of gasket width at the groove base to gasket height should be at least 2:1 in order to prevent tilting of the gasket during installation. The recovery force of the gasket depends on its height and width and on the shape of the cross section (number of cells). The recovery force and the top width of the gasket essentially determine the tightness of the joint, depending on the maximum prevailing water pressure.

To ensure compression of the gaskets towards the ends of the tunnel section, permanent longitudinal pre-stressing by means of bolts or similar devices is to be provided for over a verifiable length, at least over the length of one tunnel cross section. This also applies to other areas in which the possibility of segment rings being displaced longitudinally cannot be excluded, e.g. on either side of crosscut openings, before and after shafts, widened station areas, etc.

The gasket is to be manufactured as a closed frame to the required degree of dimensional accuracy in the gasket manufacturing plant, with due consideration given to the segment geometry, especially angles at corners. The increased tightness requirements to be met by T joints in the corners of the frame must be taken into consideration.

Prior to installation of the gasket frame, any repair measures to be performed on the groove base and groove flanks must be completed and the materials used must be completely cured. The groove area must be dry, free of dust and grease, and the adhesive used must be compatible with the gasket material. The conditions of installation specified by the manufacturer, such as temperature, humidity, etc., must be complied with.

To avoid damage to the gasket through shearing at the groove base during installation of the segment, especially the keystone, covering or coating the gasket with a lubricant is recommended.

Anchored gaskets can be used to meet high waterproofing requirements. The gasket, which is equipped with special anchoring devices on the underside, is directly embedded in concrete in the process of segment production. Thus, the seepage path of any water is prolonged and the gasket is held safely in place during installation.

The requirements to be met by the gasket are to be determined on the basis of the design water pressure, considering the safety factor specified according to [9] Item 4. The test is performed according to [9] Item 5. If a double sealing frame is used, all requirements must be met by a single frame.

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7.2.3.4 Pre-sealing

To protect the segment gasket, installation of an all-around pre-seal, sheltering the joint from contact with mortar from the annular gap or soil entering on the mountain side, is recommended. Moreover, the pre-seal prevents the entry of tailskin sealing grease into joints as well as the spread of sealing grease and annular gap mortar along the radial joint underneath the tailskin seal. The pre-seal has no function in the finished structure. Adhesive bonding of the pre-seal must be strong enough to prevent it from being dislodged through normal manipulation of the segment (Fig. 7/5).

7.3 Centring aids and connectors

7.3.1 Purpose of connectors and centring aids

The segments are temporarily or permanently connected in the radial and circumferential joints by means of connecting devices, e.g. bolts or high-strength dowels, in order to ensure a certain degree of stability during installation, to prevent displacement of the segments, and to keep the gaskets compressed during construction and, if necessary, in the finished structure. Centring aids serve to facilitate precise segment installation.

7.3.2 Movable centring aids


Guide rods and dowels can be used as movable centring aids.

Centring aids fulfil the functions of guidance, centring during segment installation and, possibly, positive locking. Guide rods are able to absorb shear forces in the radial joint, whereas dowels absorb shear and tensile forces, if any, in the circumferential joint. Absorption of shear and tensile forces is to be demonstrated through testing.

7.3.2.2 Construction and design

A guide rod in the radial joint serves to improve the precision of segment installation. Both joint surfaces have a semi-circular recess. The guide rod with a diameter of ca. 25-50 mm is fastened on one side by means of an adhesive. Usually, guide rods are used in combination with dowels in the circumferential joint; however, they can also be used in combination with other connecting devices (e.g. bolts) (Fig. 7/6 and Fig. 7/7).

Fig. 7-5 Joint design with pre-seal, gasket frame and joint insert

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The material and the dimensions of the guide rod should be such as to prevent the build-up of constraining forces in the closed joint. The edges of the recess should be “bevelled” on both sides of the rail in order to facilitate fastening of the rail in the recess. The allowable installation tolerance depends on the necessary compression of the gasket and has to be verified separately.

7.3.3 Dowels

7.3.3.1 Positioning of dowels

Dowels in circumferential joints not only serve as centring aids, but also absorb tensile and shear forces. Due to compression by the TBM jacks, no further bolt connection is required. It is important to note that dowels keep segment installation tolerances low; however, subsequent ring offset to compensate for imperfections is not possible. Dowels are suited for all segment geometries, but can only be used in circumferential joints.

7.3.3.2 Dowel design

Dowel connections must be designed to absorb the acting tensile and shear forces. The dowel-segment interaction as well as the dowel-segment-seal-strip interaction must be taken into account. The forces to be absorbed by the dowel have to be verified through testing or computation.

When inserting the dowel, care must be taken not to entrap any air or water behind the dowel, which might result in loosening of the dowel.

7.3.4 Bolts

The use of bolts for segment connection primarily serves to hold the segment in place provisionally during assembly and to ensure compression of the gaskets. Bolts absorb tensile and shear forces during installation, but can also absorb forces in the finished structure. Bolts are used in both circumferential joints and radial joints. They have to be placed immediately upon installation of the individual segment after application of the thrust jacks and, as a rule, are removed after approximately 2 tunnel diameters. In waterproof systems with double gasket frames, the holes from temporary bolt connections and/or the entire bolt system in case of permanent bolt connections have to be sealed, considering the design water pressure.

As a rule, the bolts are applied in inclined position from inside out (see Fig. 7/8), with the load being introduced from the bolt head via the bolt pocket into the segment. The bolt ends in the socket of the neighbouring segment. Washers have to be used with all bolts. In radial joints the bolts should be arranged in opposite directions in order to avoid unilateral radial forces.

Circumferential joints can also be permanently connected by means of tensile elements across the entire segment (through-tensioning), which are introduced from the free face of a newly installed segment and connected with the previous ring by means of a sleeve, a coupling or a socket (Fig. 7-9).

Fig. 7-6 Plastic guide rod in the longitudinal joint Fig. 7-7 Guide groove with guide rod in the longitudinal joint

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7.3.4.1 Requirements to be met by the connectors

The number and size of connectors depend on the construction method, the segment size and the recovery force of the gasket. The gasket should be completely compressed by the TBM presses before the bolts are tightened so that the necessary pressure can be applied and/or maintained.

Connecting devices remaining in the structure must be corrosion-proof to meet the requirements of the project (e.g. resistance to exhaust gases or chloride).

The need to seal the bolt pockets (e.g. with cement mortar or prefabricated parts) depends on the project-specific requirements.

The bolt holes must be enlarged at least by the allowable installation tolerance.

7.3.4.2 Bolt dimensioning

The torque to be applied by the impact wrenches used to tighten the connectors is to be indicated.

The bolts are to be dimensioned as a function of the design forces. The relevant forces in the radial joint and the circumferential joint are to be applied to the connectors and the segments. The bolt-segment interaction as well as the bolt-segment-gasket interaction must be taken into consideration in the dimensioning of the segment. In waterproof systems the pre-stress force generated by the connectors must be designed at least for the recovery force of the gasket frames upon complete compression of the segment joints at ambient temperature.

For plastic sockets embedded in concrete, tests must be performed to demonstrate that the pre-stress of the bolts, as a function of their intended lifetime, is not lost through creep and that the threads of the bolt do not come loose as a result of vibrations from construction work.

7.4 Joint inserts

To avoid direct contact of the concrete surfaces in the circumferential joint and to smooth out any slight manufacturing unevenness on the load transfer areas, joint inserts can be placed on the circumferential joint on the side of the segment facing away from the working face. If joint inserts are used, they must be fastened reliably on the joint surfaces. The thickness of the insert prior to installation and after absorption of all loads is to be taken into consideration for segment design. The inserts have to meet high requirements, as they must be sufficiently resilient without deforming in an uncontrolled manner. In particular, they must not act as a sliding surface, as this would cause inadmissible offset in the circumferential joints.

7.5 Joint adjustment plates

To adjust for curves, joint adjustment plates are inserted in the circumferential joints of segment ring systems with parallel joints. The thickness of these adjustment plates, made from wood material or plastic, depends on the curve radii.

Fig. 7-8 Example of segment connection Fig. 7-9 Continuous straight bolt connection in by means of inclined bolt circumferential joint (through-tensioning)

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8 PRODUCTION

8.1 Production technology

8.1.1 Mixing plant

The mixing plant must meet the requirements of a mixing plant with micro-processor control according to Austrian Standard ÖNORM B 4710-1, It. 9.6.2.3. Moreover, the mixing plant must have an automatic system to measure and document the temperature of the fresh concrete. The plant is to be designed to meet the peak daily demand. Unless otherwise indicated in the following, segments are to be produced according to Austrian Standard ÖNORM EN 13369.

8.1.2 Formwork

Formwork design is based on the required load cycles (durability) and the allowable tolerances for the segment. As a rule, stationary or mobile formwork (carousel) is used for segment production. Formwork usually consists of the following components: • Mould base • Side wall • Front wall • Mould top, counter formwork (possibility of working on the back on the segment) • Base elements for fastening of assembly parts • Gaskets • Vibration equipment As a rule, formwork must be adjustable. A test schedule is to be drawn up for maintenance and checks of dimensional stability. The test schedule is to be adapted to the requirements of production tolerances. See also Chapter 11 on “Geometric Tolerances”. Formwork has to meet specified criteria in terms of durability, resistance and dimensional accuracy. The dimensional accuracy of the formwork must be significantly higher than that of the part to be produced. To verify compliance with this requirement, credentials have to be provided by the formwork manufacturer.

8.1.3 Reinforcement

The dimensional stability of the reinforcement is essential for the durability of the segments. Besides the usual method of reinforcement tying, welded cages are also used for segment reinforcement. The transmission of forces has to be demonstrated through testing. It is important to make sure that all the welders employed are sufficiently qualified. Welded reinforcement must meet the requirements of It. 5.4.1.

To guarantee the cover to reinforcement provided for in the design, the number of spacers has to be optimised as a function of cage design. For segment surfaces likely to have an increased number of production-related blowholes (e.g. extrados of segments cast in horizontal formwork) the nominal cover to reinforcement, deviating from Austrian Standard ÖNORM EN 1992-1-1, is increased by the permissible blowhole depth. Thus, the nominal concrete cover equals the sum total of the minimum concrete cover (according to Austrian Standard ÖNORM EN 1992-1-1), the allowance for tolerances (according to Austrian Standard ÖNORM EN 1992-1-1) and the permissible blowhole depth (according to It. 6.2.6.2). In areas of load introduction (front faces, edges of exterior surfaces) and around bolt pockets, the nominal cover to reinforcement is to be determined without considering potential blowholes. The minimum cover to reinforcement must be observed in any case.

Increased structural fire protection requirements (ÖVBB Guideline on “Increased Fire Protection through Concrete in Underground Traffic Structures”) have to be considered separately. If this results in an increased concrete cover, there is no need to consider blowhole depth.

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The minimum cover to reinforcement, the permissible blowhole depth and the allowance for tolerances are to be specified (Fig. 8/1). If welded cages are used, the requirements of Austrian Standard ÖNORM EN 1992-1-1 are to be complied with. If tied cages or reinforcement optimised for the specific load case (reduced to the structurally necessary amount according to It. 5.4.1) are used, the number of spacers is to be increased because of the instability of the cage. The arrangement of spacers is to be specified by the manufacturer of the pre-cast parts.

8.1.4 Concreting and curing process

The concreting process depends on the method of production (stationary formwork/carousel). Either concrete is transported to the formwork (stationary formwork) or the formwork is transported to the concrete (carousel). As regards the cleaning of formwork, a schedule with specified cleaning and maintenance frequencies as well as regular checks of dimensional stability is to be drawn up. The allowable formwork tolerances are to be indicated. Reworking of the concrete surface is to be planned as a function of the required segment evenness, porosity and dimensional stability. It is important to bear in mind that in formwork parts positioned at a very flat angle there is always a risk of air being entrapped along the (upper) outer radius. This can be remedied by opening the mould top after pouring of the concrete and subsequently reworking the surface. If the consistency of the concrete is very stiff, there is a risk of the specified dimensions being exceeded around the filling area of the formwork after the concrete surface has been struck off. If stripping times (4 – 7 hours) are reduced through heat treatment, the rise in temperature due to the build-up of heat of hydration is to be taken into account. As a rule, heat treatment is to be discontinued at a core temperature of 40 – 50°C, as any further temperature increase might result in the concrete temperature rising above 50 – 55°C due to the heat of hydration of cement. The development of temperature is to be documented at three different measuring points, distributed over the cross section of the segment, to verify the maximum temperature difference against ambient temperature (usually for up to 72 hours).

Fig. 8-1 Cover to reinforcement according to Austrian Standard ÖNORM EN 1992-1-1

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The following values must not be exceeded: • max. temperature difference core – surface 25 K • max. temperature difference surface – ambient temperature 25 K

upon delivery to open-air storage site (If this value is exceeded, testing is required to demonstrate resistance against cracking in state I)

• max. permissible rate of cooling at the surface 10 K/h If the segment is subject to a heat treatment programme, the following additional parameters must be established: • max. concrete temperature in the core 55 °C • max. rate of heat build-up 20 K/h • max. permissible fresh concrete temperature 30 °C If heat treatment is applied, pre-storage of the segments for at least one hour is necessary. If the segment has to meet very demanding requirements in terms of durability and exposure to water, additional measures have to be taken, e.g. prolongation of pre-storage to 3 hours, use of C3

A detailed description of the curing process – both with and without heat treatment – is to be attached to the pre-construction test report. The maximum permissible fresh concrete temperature, the duration of pre-storage, the maximum rate of heat build-up and the maximum surface cooling rate are to be indicated.

A-free cement, or verification that secondary ettringite formation is excluded. For post-treatment of the concrete after formwork removal, use of a post-treatment agent is recommended, applied immediately after stripping and meeting the requirements regarding the barrier coefficient and the increased base temperature (RVS 11.06.42). Compatibility of the post-treatment agent with subsequent coatings, if any, should be ensured.

8.1.5 Production tolerances

The allowable segment production tolerances depend on the type of support (single-shell or double-shell lining) and the requirements class according to Chapter 3, Table 3/1 Definition and Description of Requirements Classes for Support Systems (see also Chapter 11).

8.1.6 Joints / Gaskets

The design of the joints and/or the gaskets is based on the allowable tolerances and the type of support (single-shell or double-shell lining) as well as the segment type. In this context, special attention should be paid to the groove and its preparation (see It. 7.2.3.1 and It. 9.5.1.8).

8.2 Handling and storage in the production plant

As a rule, prefabricated elements are manipulated by means of a gripper or a vacuum lifter with or without swivel mechanism. Shocks during handling and transport must be avoided. The compressive strength of the concrete required to absorb loads due to transport (bending moment of the young prefabricated element) is to be indicated by the design engineer and must be verified through testing by the manufacturer.

To ensure their traceability, the segments must be marked as follows: • Segment type (concrete grade/type of reinforcement) • Production date • Formwork number • Batch number on day of production

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On the basis of this continuous marking system, it must be possible to unmistakeably trace the formwork and reinforcement checks performed, the concreting and stripping times, and the corresponding dimensional checks. A project-specific system of quality assurance must be in place.

If an underlying, continuous batch numbering system ensures complete traceability of the segments produced, indication of the batch number on the day of production is not obligatory. The specific requirements of storage and assembly logistics must be observed.

Specific requirements for segment storage (e.g. bearing points, stacking height) are to be indicated by the design engineer and verified by the manufacturer. Markings on the individual segments facilitate the verification of appropriate storage.

The level of compressive strength of the concrete to be achieved prior to installation is to be indicated by the design engineer; compliance with the required strength class is to be verified.

Furthermore, the requirements specified under It. 9.1.1 apply.

8.3 Testing and production controls

8.3.1 Testing of building materials

The production controls to be performed on the concrete are listed in Chapter 6.

8.3.2 Testing of structural components

Testing of structural components in the course of production serves to verify the specified properties of the pre-cast parts, acceptance of the reinforcement and the concrete cover, dimensional stability (geometry), acceptance of other assembly parts, such as the gasket frame, the pre-seal and the joint inserts, as well as the identification of possible defects.

8.3.3 Concrete properties

The verification of the structural component properties as a function of the material properties is dealt with in Chapter 6.

8.3.4 Geometry

The stripped segments must be measured according to a specified schedule. As a rule, deviations in excess of the allowable tolerances result in elimination of the segment; the formwork used for production of the non-compliant segments is inspected and, if necessary, readjusted. The necessary test instruments, e.g. templates, dial gauges, calliper squares, precision measuring tapes, precision rulers or 3D measuring devices, must be available for use (see Chapter 11). Adequate space and logistic prerequisites are to be provided for the control measurements.

The test frequencies for different systems (with and without waterproofing) are indicated in It. 11.3.4. The measuring procedures and the measuring frequencies for segments and formwork as well as the tests to be performed on the closed segment ring are listed non-exhaustively.

8.3.5 Acceptance of segments produced

After production and prior to further use, the segments are subjected to an evaluation process and either accepted or eliminated.

The quality control documents must be available; a visual inspection for spalling, imperfections, condition of gaskets and cracks is to be performed. Acceptance of the segments is to be documented.

Interim evaluations of any kind are to help the manufacturer save unnecessary transport, handling and storage costs.

A further inspection prior to installation (It. 9.4.1) is to be provided for.

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8.4 Repair during production (in plant)

Repairs in the course of production (in plant) are to be performed in line with the provisions applicable to repairs during transport/installation (It. 9.5).

9 INSTALLATION

9.1 General remarks

To avoid damage to the segments during transport from the production plant to the site of installation, a quality management system (QMS) should be provided for. Basically, the provisions of Austrian Standard ÖNORM EN 13369 apply. As a minimum requirement, the QMS should cover the aspects referred to in Items 9.1.1 and 9.1.2 as well as 9.4 and 9.5.

9.1.1 Storage

The segments are to be stored in such a way as to protect them from detrimental climatic influences. Loads as well as deformations during storage are to be considered.

Segments can be stored either by segment ring or by segment type. • In the case of storage by ring, the segments forming one ring are stacked on top of each other.

Grouping for transport to the tunnel site is not necessary. The rings are to be stacked in the order of their installation.

• In the case of storage by type, segments of the same type and approximately the same age are stored together. Damaged segments can easily be removed without restacking. If segments are transported by type, transport capacities can be utilised more efficiently.

For storage of segments at the construction site or an interim storage site, the following additional aspects need to be considered: • The logistics of arrival at and departure from the site must be well organised; sufficient space

must be available for loading and unloading. • The requirements to be met by the segment storage site have to be accurately defined. In

particular, the total storage area required, the facilities needed at the storage site and the load-bearing capacity and evenness requirements of the area must be defined.

• If segments are to be stored horizontally, the dimension of and distance between the wooden stacking supports (as statically required for stacked segments) need to be indicated.

• The number of segments that can be stacked on top of each other (statically determined!) must be indicated for both horizontal and vertical storage.

• A suitable lifting device (e.g. distance between forks, distance between loops) is to be chosen for segment transport.

If need arises, finishing work on the segments can also be performed at the storage site.

9.1.2 Transport

The requirements for segment transport (e.g. stackability of segments for transport, maximum transport weight and other traffic restrictions, strength of concrete at the time of transport) are to be considered.

As regards the transport of segments from the production plant to the storage site and/or from the storage site to the site of installation, special attention must be paid to the availability of additional interim storage or handling sites (e.g. reloading of segments from wheel-bound to track-bound vehicles in the portal area). These interim storage sites also have to meet specific requirements.

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9.2 Building of the segment ring – Mechanical engineering requirements


The mechanical engineering requirements depend on the geological conditions of the site, the ingress of water to be expected, the segmental system used and the need for support of the excavated cavity and the tunnel face. All equipment used must be designed to prevent damage to segment surfaces and edges and to ensure installation of the segments in the correct position. The introduction of thrust forces must be such as to prevent damage to or displacement of the segments beyond the specified tolerances.

9.2.2 Thrust jacks

The number and arrangement of thrust jacks and the segment design must be adjusted to each other. The capacity of the thrust jacks is to be determined as a function of the entire thrust required. The eccentricity of force application is to be taken into consideration. The design and control of the individual thrust jacks or groups of thrust jacks must be such as to permit individual hydraulic jacking during the installation of the segment ring. For certain types of segmental systems (e.g. “Swiss stacking system” to It. 3.3.1), the use of a thrust ring is necessary. In this case, special installation measures must be provided for (see Chapter 10).

The jacking pads must be designed for smooth and unconstrained force introduction into the segments.

9.2.3 Segment gantry and erector

The segment gantry and the erector are to be designed for the expected maximum segment weight, with due consideration given to dynamic loads (Chapter 4).

The design of the segment gantry must be such as to permit unconstrained segment take-up and unimpeded transport from the point of unloading to the segment feeder.

Except for the keystone, the erector has to ensure constraint-free take-up and form-fitting installation of the segments. The erector must be able to perform the following motions independently of each other: • shifting in the longitudinal tunnel direction • rotation around the shield axis by 360° • radial extension and retraction • tilting of the erector head along and across the tunnel axis • tilting of the erector head across the tunnel • swivelling of the erector head A precision control system must be available for all the above motions. For segment systems with guide dowels and guide rods, the degrees of freedom at the erector should be freely variable in order to avoid assembly-related constraints.

The control panel of the segment gantry and the erector must be arranged in such a way as to permit a direct view of the segment during transport and installation. Segments are picked up by means of suction plates or pick-up pins.

In the case of sealed segments, the working range of the erector must be wide enough to allow repair work to be carried out on the tailskin seal (larger working range in the direction of the tailskin seal).

Adjusted to the segmental system used, the erector must be designed to allow complete pre-stressing of the gaskets in the segment joints during assembly.

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9.2.4 Tailskin seal

9.2.4.1 Inner tailskin seal

The tailskin seal, which seals the annular gap between the inside of the tailskin and the segment ring, prevents leaking of pea gravel, mortar or grout from the annular gap. It is to be designed in such a way as to ensure tight closure of the gap even if the segment ring is in an eccentric position. Depending on specific requirements, a system with multiple seal rings may be required. Replacing and repairing the seal from the inside must be possible.

A tailskin seal is to be provided for and maintained in good condition, if the segments must be fully bedded immediately behind the shield tunnelling machine to guarantee the stability of the segment ring.

9.2.4.2 Outer tailskin seal

The outer tailskin seal serves to seal the annular gap between the outside of the tailskin and the rock mass against the entry of pea gravel and/or mortar or grout into the shield area. In particular, seals of this type are required in side wall areas, if the wall segment needs to be fully bedded immediately behind the shield.

9.3 Loads due to tunnel advance

Depending on the type of shield machine used, the thrust is introduced either directly into the segments or via gripper pads into the rock mass.

As the machine advances, the segments are subject to substantial loads. The introduction of forces should be such as to ensure a centric, uniform and wide distribution of thrust forces in order to avoid spalling as a result of overloading.

In the presence of squeezing rock or other constraining forces, it may be necessary to increase the thrust force substantially over a short period of time in order to free the machine. This is likely to result in damage to exposed segments. The level of thrust to be applied and the repair measures to be taken are to be agreed upon with the Owner.

9.4 Segment control and inspection

Prior to installation, the segments are subjected to a general evaluation based on the contact provisions and examined in detail on the basis of the criteria of release for transport; on that basis, they are either accepted or rejected. Interim evaluations of any kind are to help the segment manufacturer avoid unnecessary expenses for transport, handling and storage, but their results are without prejudice to the final inspection outcome. For segments not subject to conformity testing (according to It. 6.4.2, Table 6/2) or identity testing (according to It. 6.4.3, Table 6/3), special provisions are to be included in the contract by the tendering authority. In the interest of cost-efficiency, it is recommended that individual non-compliant segments be subjected to a technical evaluation with regard to their fitness for use and, provided they are fit for use, their installation be permitted subject to a special provision (quality discount).

9.4.1 At the construction site above ground

Final acceptance takes place on the basis of the interim inspection performed and the manufacturer’s own production control, including final visual inspection at the last storage site before transport into the tunnel. To prevent delays during installation in the tunnel, defects of segments and gaskets should be identified in time through joint inspection by the Owner and the Contractor prior to transport into the tunnel. Every segment must be identified and visually inspected for inadmissible defects.

If defective segments are identified, the procedure according to It. 9.5.4 applies.

Moreover, the age of the segments, as an indication of the level of compressive strength to be expected, is to be checked.

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9.4.2 In the tunnel prior to installation underground

Together, the Owner and the Contractor have to identify any defects due to transport from the storage site to the place of installation. If the defects cannot be repaired, the segments concerned are to be eliminated.

9.4.3 Inspections after installation

Segment defects (e.g. due to installation, thrust forces, forces from back-up equipment, rock pressure, etc.) are to be identified by the Owner and the Ccontractor; a detailed documentation of the defects identified is to be kept by the Contractor.

Similarly, compliance with the permissible values specified in the contract for segment misalignment, joint width, water ingress through leaking joints and segment leakages is to be established jointly by the Owner and the Contractor and documented by the Contractor.

Ovalisation of the tunnel is to be verified through deformation measurements performed by the Contractor.

9.5 Repair of segments

Frequent types of defects are described in the following. Defects are classified by location, as the possibility of repairing a defect essentially depends on where it is located. Given the fact that the elimination of defective segments has a major impact on manufacturing costs, the criteria for elimination must be clearly described.

Very small defects (below the limits of the matrix in Table 9/1 and/or 9/2) with no impact on the durability and serviceability of the segment are not defined as defects for the purposes of this Guideline.

9.5.1 Definition of the most frequent types of defects


Defects requiring the repair of segments not complying with the specified parameters are described in the following.

9.5.1.2 Nest formation

Nests are defects in the segment caused by partly insufficient compaction of the concrete or leakage of cement paste from leaking moulds (Fig. 9-1, Fig. 9-2).

Fig. 9-1 Example 1: “nest formation” defect Fig. 9-2 Example 2: “nest formation” defect

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9.5.1.3 Missing concrete parts

Missing concrete parts are defects due to insufficient filling of the mould with concrete (Fig 9/3).

9.5.1.4 Inadmissible blowholes

Inadmissible blowholes are defects on the concrete surface caused by air entrapped in the formwork (usually at the counter-formwork) and exceeding the specified depth and permissible frequency (Fig. 9-4).

9.5.1.5 Tear-off and spalling

Tear-off and spalling defects in hardened concrete are caused by de-moulding at insufficient concrete strength, inappropriate transport or installation (Fig. 9-5, Fig. 9-6, Fig. 9-7).

Fig. 9-3 Example of defect: Fig. 9-4 Example of defect: “inadmissible “missing concrete part” blowhole” with concrete cover below the required minimum

Fig. 9-5 Example: spalling, torn edge Fig. 9-6 Example: spalling, torn edge

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9.5.1.6 Inadequate cover to reinforcement

For structural reasons, the concrete cover to reinforcement must not be less than the required minimum (Austrian Standard ÖNORM EN 1992-1-1). If the concrete cover is sufficient to ensure bonding with the reinforcement, but insufficient in view of the prevailing environmental conditions (Austrian Standard ÖNORM EN 1992-1-1), the measures specified in It. 9.5.4 apply.

9.5.1.7 Inadmissible cracks

As a rule, cracks in installed segments (Fig. 9-9, Fig. 9-10), waterproof or permeable, are inadmissible, if their width exceeds the limits specified in Table 3/1. Specifications for segments before and after installation are to be indicated by the design engineer (see Tables 9/1 and 9/2).

Fig. 9-7 Example: spalling of installed segment Fig. 9-8 Separation crack

Fig. 9-9 Separation crack Fig. 9-10 Permissible crack

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9.5.1.8 Gasket and gasket groove

9.5.1.8.1 Crack

Cracks in the groove base must not be wider than 0.15 mm and/or extend over more than 30% of the groove base.

Cracks over the entire groove width of the sealing frame are inadmissible (Fig. 9-11)

9.5.1.8.2 Blowholes

Prior to the assessment of blowholes, the base and flanks of the groove must be cleaned by means of a steel brush. The repair of blowholes extending over more than 30% of the groove base is not permitted. The total area of blowholes must not exceed 3P (0.9% relative to the groove base area on each segment face). The repair of blowholes extending over a length of more than 15 mm in the groove flank is subject to agreement by the Owner. If the Owner’s agreement is not obtained, the segments concerned must be eliminated (Fig. 9-12 and Fig. 9-13).

Fig. 9-11 Inadmissible crack Fig. 9-12 Repair of blowholes after consultation with Owner

Fig. 9-13 Blowhole width > 1/3 Fig. 9-14 Inadmissible nest formation of groove base area in gasket area

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9.5.1.8.3 Nests

Nests are not acceptable (Fig. 9-14).

9.5.1.8.4 Tear-off and spalling

Tear-off and spalling is not permissible (Fig. 9-15, Fig. 9-16, Fig. 9-17).,

Fig. 9-15 Inadmissible spalling Fig. 9-16 Inadmissible spalling during production during transport

Fig. 9-17 Inadmissible spalling Fig. 9-18 Loose gasket frame during installation

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9.5.1.8.5 Gasket frame

Damage to the gasket frame and defective bonding are not acceptable (Fig. 9-19).

9.5.1.9 Other defects

Other defects are defects resulting from necessary operations, such as core drilling, dowelling, etc. As a rule, such defects are to be closed (Fig. 9-20).

9.5.2 Types of defects

The repair measure to be taken depends on where the defect has occurred. Defects may either be due to the production process or result from damage to segments during transport or during and after installation.

Due to time constraints, damage to segments caused during transport from the portal to the place of installation or during installation can only be repaired to a limited extent.

9.5.2.1 Types of defects occurring during production:

• Nest formation • Missing concrete parts • Inadmissible blowholes • Tear-off and spalling • Concrete cover below required minimum • Cracks • Gaskets

− cracks − blowholes − nest formation − tear-off and spalling − gasket frame

• Cracks • Other defects

9.5.2.2 Types of defects due to handling and transport

• Cracks • Spalling • Gasket damage

Fig. 9-19 Damaged gasket frame Fig. 9-20 Spalling at dowel hole

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9.5.2.3 Types of defects due to damage during and after installation

• Spalling • Cracks • Gasket damage • Other defects

9.5.3 Repair of defects

The need for repair of concrete defects depends on the requirements to be met by the segment as specified in the design documents. The type of repair measure to be taken depends on the origin of the defect and its location on the segment. Not all segment defects can or must be repaired. The criteria for eliminating defective segments are to be specified in the design documents.

A repair plan, complete with working instructions, is to be drawn up. As a minimum, it has to cover the following items:

• Types of defects • Criteria for repair • Repair measures • Products used for repairs • Documentation (segment number, type of defect, etc.) Demanding requirements have to be met in terms of staff qualifications and the products used. Staff qualifications have to be documented through training certificates and/or credentials from prior experience.

The repair of segments must be performed in accordance with the ÖVBB Guideline on the “Maintenance and Repair of Concrete and Reinforced Concrete Structures”. Moreover, for segments meeting the requirements of increased fire protection, the ÖVBB Data Sheet on “Protective Coatings for Increased Fire Protection for Underground Traffic Structures” applies.

Products used for segment repair must comply with these Guidelines. Deviating from the provisions of the ÖVBB Guideline on the “Maintenance and Repair of Concrete and Reinforced Concrete Structures”, the quality of repair is verified through testing of trial segments (e.g. test segment according to It. 6.4.1) and random sampling. The scope of testing is to be indicated by the design engineer.

9.5.3.1 Repair during production

If the repair is performed immediately after de-moulding, it must be demonstrated through testing that the products used are suitable under these conditions (e.g. high segment temperature).

9.5.3.2 Repair at the site of installation

As a rule, segment repair at the site of installation is only provided for if segments have been damaged during transport from the portal to the site of installation. Owing to time constraints, the possibilities of repair are limited. Segments which cannot be repaired prior to or after installation must not be installed.

9.5.3.3 Repair after installation

As a rule, segment repair after installation is only provided for if segments have been damaged during transport from the portal to the installation site or during or after installation. The repair of defects after installation is only possible on the inside (air-side) of the segment.

9.5.4 Repair matrix


The following definitions and explanations apply to the matrix below:

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• “Defects” are classified by the design engineer by “type of defect” (e.g. crack), “location” and “extent” (e.g. x = 0.3 mm for segment without waterproofing – measure 2).

• For a definition of “type of defect”, see It. 9.5.2 • Defects are classified by “location”, as the effect of defects may vary with their location on the

segment. • The “extent” of the defect (x, y, z) is to be specified by the design engineer on a project-specific

basis. “x, y, z” refer to a measure of width (e.g. crack width) or length, an area or a verbal description to be specified as a limit for the corresponding “measure by place of origin” (Fig. 9-21).

• As a rule, the specifications in the following tables for “measures by place of origin” apply (Table 9/1 and Table 9/2).

Fig. 9-21 Classification of defect types by area in sealed segments

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“Measures by place of origin” are defined as follows:

1 no repair required

2 repair measures required

3 no repair permitted (segment to be eliminated)

9.5.4.2 Unsealed segmental system

Defects Measure by origin of defect Note

Type of defect Area Extent Production Transport Installed Nests Load transfer

area x 2 - - y 3 - -

Other areas x 2 - - y 3 - -

Missing concrete parts

Load transfer area

x 2 - - y 3 - -


Blowholes Load transfer area

x 1 - - y 2 - - z 3 - -


Tear-off and spalling

Load transfer area

x 2 2 2 y 3 3 2

Other areas x 1 1 1 y 2 2 2

Concete cover Load transfer area

x 2 - - cm² permissible repair surface y 3 - -

Other areas x 2 - - Cracks Load transfer

area and other areas

x 1 1 1 y 2 2 2 z 3 3 2

Other defects (e.g. core drilling)

Load transfer area 2 - 2

Other areas 2 2 2 Core drilling during production

Table 9/1 Treatment of defects in unsealed segmental systems

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9.5.4.3 Sealed segmental system

Defects Measure by origin of defect Note

Type of defect Area Extent Production Transport Installed

Nests Load transfer area

x 2 - - y 3 - -

Gasket area - 3 - - Other areas - 2 - -

Missing concrete parts

Load transfer area

x 2 - - y 3 - -


Blowholes Load transfer area

x 1 - - y 2 - -

Gasket area x 1 - - y 2 - - z 3 - -


Tear-off and spalling

Load transfer area

x 2 2 2 y 3 3 2

Gasket area - 3 3 2

Other areas x 1 1 1 y 2 2 2

Concrete cover

Load transfer area

x 2 - - cm² permissible repair surface y 3 - -


Cracks Load transfer area and other areas

x 1 1 1 y 2 2 2 z 3 3 2

Gasket area x 2 2 2 y 3 3 2

Other defects (e.g. core drilling)

Load transfer area 2 - 2

Gasket area 3 - 2

Other areas 2 2 2 Core drilling during production

Gasket

Damaged frame 2 2 2

Frame to be replaced if damaged during transport and production

Bonding 2 2 2

Table 9/2 Treatment of defects in sealed segmental systems

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10 BACKFILLING OF THE ANNULUS

10.1 General remarks

The stability of the segment system is achieved through the interaction of the ring of pre-cast concrete parts with the annulus backfill. Backfilling of the annular gap serves to embed the segment ring in the surrounding rock mass. Timely backfilling of the annular gap between the outside face of the segment ring and the excavated cavity is of utmost importance in a tunnel construction with segmental lining. For impermeable segmental systems, tunnelling without grouting of the annulus through appropriate measures is inconceivable.

10.2 Support conditions, bedding principles and requirements

10.2.1 Support conditions

Different rock mass types, such as solid rock and loose ground in combination with rock and/or ground water, demand different types of tunnel boring machines (TBM) as well as appropriate segmental systems and annulus backfilling methods.

The principle of ensuring immediate and sufficient bedding of the segment ring applies to all types of machines and segmental systems.

Sufficient bedding of the segment ring immediately behind the tailskin must be ensured.

• In shield machines (SM), the backfilling material is usually fed via grouting tubes in the tailskin area under permanent volume and pressure control.

• In tunnel boring machines (TBM-S and/or TBM-DS) the backfilling material for the invert area (mortar) is applied via grouting tubes or holes. In all other areas, backfilling material (pea gravel and/or mortar) can be fed via backfilling holes in the segments. The rate of backfilling of the annulus depends on the rate of advance.

In drained tunnel structures the backfilling material should not interfere with the functioning of the permanent drainage system. When selecting the type of backfilling material, special care should be taken to keep sinter formation at a minimum.

Erosion of the backfill must be prevented.

If segment joints have a role to play in the drainage system, they must not lose their permanent drainage function.

In the presence of large quantities of water and/or potential sinter formation, the drainage capacity of the joints on the inside face of the segments may have to be increased. If the backfill material in the annular gap is subsequently grouted, the possibility of water drainage from the finished structure after closure of the joints must be maintained (possibly through relief borings).

10.2.2 Bedding principles

10.2.2.1 TBM-O and TBM-DS without segmental support

In these cases, the tunnel is built with a conventional support system, i.e. shotcrete, reinforced steel mesh, rock bolts, arches, etc., possibly with an invert segment for the tunnel floor. The gap underneath the segment must be fully backfilled with mortar.

10.2.2.2 TBM-S and TBM-DS with segmental support

In the process of backfilling the annular gap, conditions may occur under which the segment ring is only partially bedded immediately behind the tailskin. Special attention must be given to such conditions in the process of planning, structural analysis and execution.

If pea gravel is used, bedding may be insufficient behind the tailskin, as gravel keeps flowing into the gap while the machine advances. This is due to the fact that a flowing medium does not ensure adequate bedding. The stability of the backfill material can be improved by using a mix of pea

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gravel and mortar (see It. 10.2.3.3). Therefore, pre-stressing of the partially bedded areas in the longitudinal direction of the tunnel by means of the thrust jacks and/or other means of longitudinal pre-stressing is necessary. Prior to pre-stress relief, complete bedding according to It. 10.2.3.2 must be ensured.

In the absence of an outer tailskin seal, care must be taken in narrow curves to prevent the entry of pea gravel into the shield, which would cause problems for shield driving and shield steering.

Backfilling of the crown area with pea gravel is only possible at a distance of approx. 2/3 D.

If mortar is used to backfill the annular gap in hard rock, vibrations caused by the advancing machine may result in even relatively stiff mortar mixes penetrating into the shield area. In the event of a longer machine standstill, there is a risk of mortar stiffening and blocking the shield.

10.2.2.3 Shield machine SM (hydro shield, earth-pressure shield, etc.)

When shield machines are used, especially in loose ground and under ground water pressure, the annulus is backfilled continuously as the machine advances. The annulus is filled all around via grouting tubes in the tailskin under controlled pressure (with the volume being documented), so that the segment rings can always be bedded and positively locked.

The grouting mortar is to be prepared and distributed in such a way as to ensure sufficient bedding of the tunnel tube, i.e. to prevent any uplift of the tube. Displacement (subsidence) of the segment rings must be prevented.

The theoretical calculation of the required grout quantity also has to consider the possibility of grout penetrating into rock fissures and cavities from rock falls.

10.2.3 Bedding requirements

10.2.3.1 General requirements

The requirements regarding bedding of the segment ring are to be specified. The bedding stiffness is to match the surrounding rock mass.

The mortar must be sufficiently flowable and must not stiffen prematurely in the grouting tubes.

Through discharge of filtration water into the surrounding rock mass, the support action of the grain skeleton of the mortar should be activated.

The required compressive strength of the mortar backfill is to be specified.

The early strength properties are to be adjusted to the requirements of construction operations.

10.2.3.2 TBM-O

The quality of bedding to be achieved through backfilling of the space between the invert segment and the rock mass is largely determined by the demands of construction operations, early loading of the invert segment through back-up equipment and track-bound transport.

10.2.3.3 TBM-S and TBM-DS

The requirements to be met by backfilling of the annulus in permeable systems can be defined as follows:

• Invert area Up to an opening angle of max. 100° the annular gap is to be grouted with mortar. In the case of large TBM diameters (≥ 9 m), grouting is performed via grouting tubes in the tailskin as the machine advances. With smaller TBM diameters (< 9 m), grout can also be introduced through grout holes in the invert. If pea ravel is backfilled into the annular gap in the side wall area, it cannot be prevented from penetrating to the shield and/or into the annulus of the invert not yet grouted. Reducing the opening angle for mortar backfilling is permitted, if complete filling of

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this area with pea gravel can be guaranteed. If a smaller TBM is used, the holes for backfilling have to be positioned in such a way as to allow backfilling of the annulus to begin as soon as the TBM starts to advance.

• Backfilling of side wall and crown areas with pea gravel A sufficient number of backfilling holes, especially in the wall-to-crown transition area, must be provided for. In parallel with the advance of the shield, backfilling of the side wall areas with pea gravel must be started. 2/3 D behind the tailskin, at the latest, the backfill must come up to the tunnel crown. Project-specific exceptions, i.e. less demanding requirements in stable rock (e.g. later backfilling) or more demanding requirements in weak rock (e.g. tunnel advance and backfilling in partial strokes), are to be decided by the design engineer, depending on rock mass conditions and/or the purpose of the structure. If complete filling of the crown area is not possible after 2/3 D (e.g. rotating ring system or clogged filling holes), an additional step may be required to complete backfilling with pea gravel or grouting with mortar. If the TBM is equipped with a thrust ring, the following applies: As soon as the segment ring has been ejected from the tailskin, the side wall area is to be filled with pea gravel up to a height to be specified by the design engineer (e.g. 50 cm below the radial joint between the side wall and crown segments); filling must be guaranteed upon withdrawal of the thrust ring.

• Side wall and crown area with additional mortar backfill If complete backfilling of the annulus with pea gravel cannot be guaranteed due to subsidence of the rock mass and/or blockage of the annulus, the annular gap has to be grouted with mortar. Another possibility consists in filling the annulus with a gavel/mortar mix, with mortar being fed into the pea gavel flow by compressed air via a y-branch pipe (Fig. 10-1). If the annulus backfill needs to be post-grouted (see It. 10.6), backfilling with mortar may not always be required.

• Side wall and crown area fully grouted with mortar See It. 10.3.2.4. The penetration of mortar into the shield is to be prevented by means of an outer tailskin seal.

• Loosened rock mass in the crown area If a tendency of the rock mass to subside is observed at the shield or foamed cavities have been documented, core drillings are to be made in the crown to verify the presence of loose rock and/or cavities above the crown, in which case the rock mass is to be pressure grouted.

Fig. 10-1 Backfilling with gavel/mortar mix Fig. 10-2 Backfilling with round-grain through y-branch pipe pea gravel

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In addition, the following requirements have to be met for impermeable systems:

In particular, complete bedding of the segment ring is essential to ensure permanent pre-stressing of the gaskets of the radial joints. If necessary, permanent pre-stressing of the gasket is to be ensured through the use of connectors.

10.2.3.4 SM shield machine with face support (earth pressure shield, hydro shield)

The backfill material must be continuously injected into the annulus through ducts in the tailskin area as the machine advances. The equipment used for grouting of the annulus must ensure an even distribution of the grout (grouting mortar) over the entire circumference of the segment ring. Given the risk of excessive strain on the segment ring, special care must be taken to ensure a continuous grouting procedure without major variations in grouting pressure.

As a rule, the pressure to be applied for annulus grouting is more or less the same as the support pressure in the excavation chamber.

10.2.4 Monitoring and control of filling level and bedding

The dimensional stability of the segment ring during backfilling must be guaranteed. Crack formation in the crown segment may be an indication of insufficient bedding and/or rock loads imposed on the crown segment.

If bedding of the side wall segment in pea gravel and/or mortar after its ejection from the tailskin cannot be guaranteed, alternative means of support, e.g. adjusting screws, mortar bags with instant cement, etc., can be used to remedy the situation.

10.2.4.1 Checking the filling level

The filling level in the annulus has to be checked continuously while material is being backfilled into the gap. As a rule, the filling level is checked by comparing actual material consumption with the annular gap volume.

Due to vibrations of the advancing machine, post-compaction of the backfill material may occur. Therefore, the filling level has to be checked continuously also in the back-up area; if necessary, additional pea gravel and/or mortar have to be filled into the gap. In impermeable systems with mortar grouting, monitoring and control systems must be in place to provide for grouting pressure and volume control.

10.2.4.2 Checking the quality of bedding

Chord measurements (e.g. by hand-held laser device, theodolite or scanner) have proved to be useful indicators of the quality of bedding and/or the need for additional mortar grouting or backfilling with pea gravel in crown and/or side wall areas; they also facilitate monitoring of crack formation and misalignment.

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10.3 Annulus grouting mortar

10.3.1 Properties

As a rule, annulus grouting mortar has to have the following properties: • Volumetric stability in hardened condition • Positive locking between the support and the rock mass • No harmful effect on ground water • Good workability • Good pumpability • High settling stability • Stiffness adjusted to rock mass • Compressive strength > 0.12 N/mm² after 24 hours • Erosion resistance in the presence of flowing ground water The minimum compressive strength after 28 days is to be specified. The strength development of the backfill is to be adjusted to the bedding conditions behind the shield.

The test procedures are indicated in It. 10.3.3.

For special cases, e.g. compressible mortar [10], special requirements are to be defined.

10.3.2 Mortar constituents

10.3.2.1 Standard requirements

• Cement The cement used has to meet the requirements of EN 197-1; sulphate-resistant cement has to comply with Austrian Standard ÖNORM B 3327-2.

• Additives Products admissible for use as additives must meet the requirements of Austrian Standard ÖNORM B 3309 (AHWZ), Austrian Standard ÖNORM EN 450 (fly ash), Austrian Standard ÖNORM EN 13263 (silica dust) and Austrian Standard ÖNORM EN 12620 (rock meal).

• Mineral aggregate The mineral aggregate must be in accordance with Austrian Standard B 3131 and/or meet the requirements of Austrian Standard ÖNORM B 4710-1 for the required exposure class. As a rule, the maximum grain size is 4 mm. CaCO3

• Make-up water content < 10 %, if necessary (problem of sintering)

Make-up water has to meet the requirements of Austrian Standard ÖNORM EN 1008. • Admixtures

Plasticisers and, if necessary, air-entraining agents, accelerators, retardants and stabilisers are used as admixtures. All admixtures must meet the requirements of Austrian Standard ÖNORM EN 934-2.

• Bentonite Bentonite must meet the requirements of German Standard DIN 4127.

10.3.2.2 Mortar containing accelerator (two-component process)

If immediate strength development of the mortar is required, the process can be speeded up through the addition of an accelerator. A mature technology for mixing and dosing of the accelerator was not yet available when this Guideline was drafted.

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10.3.2.3 Sulphate-resistant mortar

Mortar exposed to chemical attack must meet the requirements of Austrian Standard ÖNORM B 4710-1. In the case of sulphate attack, sulphate-resistant cement according to Austrian Standard ÖNORM B 3327-2 is to be used. Lime-containing additives (limestone meal) must not be used (thaumasite formation).

10.3.2.4 Problems of sintering in the annulus

In drained tunnel structures special care must be taken in the selection of aggregates and binders to prevent sintering. The optimum binder is CEM III/B cement, or – in the case of sulphate attack - C3Afree cement without limestone, but with prepared hydraulically active additives according to Austrian Standard ÖNORM B 3309. The CaCO3

10.3.3 Checking and testing – Mortar

content of the binder must not exceed 5 %.

Pre-construction test

The composition of the mortar is to be established through pre-construction testing. The following information is to be included in the pre-construction test report: • Client • Testing institute • Date of testing • Constituent materials used • Verification of suitability of constituent materials • Composition for 1 m³ of mortar • Fresh mortar properties:

− Setting according to ASTM C 403 − W/B value − Bulk density according to Austrian Standard ÖNORM EN 12350-6 − Slump and slump flow according to Austrian Standard ÖNORM EN 12350-5 for the

specified workability time − Void content according to Austrian Standard ÖNORM EN 12350-7 (if necessary) − Settling behaviour (1000 ml cylinder, after 2 hours) according to Austrian Standard ÖNORM

B 4452 − Filtration water according to Austrian Standard ÖNORM B 4452

• Mortar properties: − Compressive strength after 24 hours, 7 and 28 days according to Austrian Standard ÖNORM

B 4452 − Exposure classes (to be specified by the design engineer) − Pinhole test according to Austrian Standard ÖNORM B 4452

Conformity tests

Conformity testing of the properties of mortar has to include the following: • Constituent materials:

− Continuous monitoring of supply chain • Fresh mortar:

− Void content, slump (and/or slump flow), bulk density daily − Bleeding and water content every 100 m

• Mortar − Every 250 m, from 1000 m every 500 m, compressive strength testing after 24 hours (if

required), 7 and 28 days. − Exposure classes every 1000 m (if required)

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Identity tests

An identity test is to be performed every 2000 m, covering the following: • Checking the grading lines of the mineral aggregate • Fresh mortar

− Void content (if required) − Slump and/or slump flow − Bleeding − Bulk density − Water content

• Mortar − Compressive strength after 24 hours (if required) and 28 days − Exposure classes (if required)

10.4 Pea gravel

10.4.1 Requirements

Pea gravel is single-size gravel. Preferably, pea gravel consists of washed round grain with grain diameters ranging between a minimum of 4 mm and a maximum of 16 mm (Fig. 10/2). The grain fraction, which depends on the conditions of application and a possible need for post-grouting, is to be determined by the design engineer, with due consideration given to the percentages of oversized and undersized grains. The 8/11 fraction has particularly favourable properties (see also It. 14.1). Grain with more than 50% of its surface naturally rounded is called round grain. The percentage of round grain is to be determined in a sample of at least 200 grains in weight by volume. The minimum requirements to be met by pea gravel are specified as follows (see also Austrian Standard ÖNORM EN 12620): • Percentage oversized grain < 10 % to next larger screen • Percentage undersized grain < 10 % to next smaller screen • SI• Frost class F2

15

• f• LA

1,5

• 95 % rounded grain 30

If post-grouting of the backfill material in the annulus is to be performed, pea gravel has to meet the following requirements:

• AS0,8

• Constituents that change the setting behaviour of concrete must not be used.

(limitation of sulphate content in mineral aggregates according to Austrian Standard ÖNORM EN 12620)

If sintering is to be expected, gravel with a low calcification potential containing < 10 % CaCO3

In special cases, angular pea gravel can be used. However, it should be borne in mind that its workability properties are less favourable. The requirements to be met are the same as for round-grained pea gravel, except for the percentage of round grain. Special crushers can be used to improve the grain shape of pea gravel.

by weight is to be used in drained tunnel structures for reasons of maintenance.

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Furthermore, the following requirements apply:

• Grain size: The grain size must be such that, depending on the angular grain available, unobstructed filling of the annulus (no clogging) is possible.

• Degree of compaction: The composition of the angular grain mix must be such as to obtain the lowest possible compactibility in order to prevent damage to the segmental system (shifting, load rearrangement, etc.) through subsequent compaction, e.g. due to vibrations caused by tunnel driving.

If angular grain is to be blown into the annular gap under compressed air, the following additional measures may have to be taken:

• The addition of water improves the distribution of the filling material. This is only permissible if the water added does not have a negative impact on the surrounding rock mass.

• The increased wear and tear of the conveying equipment as well as the blowlines and hoses is to be borne in mind.

10.4.2 10.4.2 Inspection and testing

Pre-construction test

Testing and classification (except for the percentages of oversized and undersized grains) has to be performed according to Austrian Standard ÖNORM EN 12620. Bulk density testing is to be performed according to Austrian Standard ÖNORM EN 1097-3.

The following information is to be included in the pre-construction test report: • Client • Testing institute • Date of testing • Manufacturer and plant • Parameters:

− Grading line − Fines content − Grain shape − Bulk density − Percentage of round grain − Resistance against crushing − Frost class − CaCO3

− Acid-soluble sulphate – if required

− Content of retarding admixtures Conformity tests

Conformity tests to verify the properties of pea gavel have to be performed every 500 m, covering the following: • Monitoring of the supply chain • Grading line • Fines content • Grain shape • Bulk density • Frost class

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• Percentage of round grain • Content of retarding admixtures • CaCO3

Identity tests – if required

An identity test is to be performed every 2000 m, covering the following: • Parameters:

− Grading line − Fines content − Grain shape − Bulk density − Percentage of round grain − Resistance against crushing − Frost class − CaCO3

− Acid-soluble sulphate – if required

− Content of retarding admixtures

10.5 Sealing of joints


Depending on the requirements to be met by the surface of the tunnel lining (e.g. water tunnel, single-shell tunnel, etc.), joint sealing may be necessary.

Prior to post-grouting of the annulus backfill material with low-viscosity grout, the segment joints have to be sealed (possibly from the back-up area). The joints must be cleaned before being sealed. Defects in the joint area must be repaired.

By applying joint mortar either manually or by means of a nozzle or spray jet, the joint must be filled completely with mortar. The surface must be smooth and flush with the adjacent segments.

If water is present in and around the joints, a suitable type of mortar must be used which adheres to the joint despite being wet. In the presence of large quantities of water, the joint is to be sealed by draining the water though hoses and subsequently grouting the openings.

10.5.2 Requirements to be met by joint mortar

Joint mortar must have the right consistency and suppleness to adhere to the joint and not to come loose when applied overhead. The joint mortar must have a stability corresponding to the exposure class of the segment concrete and be shrink-compensated. The required compressive strength is to be specified and must be verified, unless otherwise indicated, in 4 x 4 x 16 cm prisms in analogy to EN 196-1.

10.6 Post-grouting of annulus backfill

10.6.1 Requirements

Under certain geological and geo-technical conditions, as well as in cases of holes being cut into the finished segment ring for niches, crosscuts, emergency exits, etc., post-grouting of the pea gravel backfilled into the annulus is necessary. In variable stable rock formations (e.g. flysch), in which complete bedding cannot be guaranteed in the long run, or in areas of overloaded, subsiding rock and/or rock falls from jointed rock mass in which complete bedding through pea gravel and/or mortar alone cannot be guaranteed, post-grouting is required. Moreover, grouted cut-off structures may be required for hydro-geological reasons, e.g. to reduce the flow of rock/ground water.

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In any case, post-grouting work should be performed behind the back-up system, with equipment separate from the TBM advance. All the equipment required for post-grouting should be contained in a separate unit. Additional borings may have to be provided for. In permeable systems, the segment joints have to be sealed in advance. Post-grouting is performed through the holes already used for backfilling with pea gravel at a minimum pressure of 0.5 bar at the crown packer. For post-grouting, the following criteria are to be specified:

• Properties of the grout, such as strength, settling behaviour and stability • Grouting procedure

Determination of grouting sequence (which grout holes are to be grouted and in which order) and grouting pressure to be reached (e.g. 0.5 bar grouting pressure in the crown, measured at the grout hole) and/or the maximum pressure to avoid damage to the segmental system

• Checks to be performed: Documentation of grout penetration (grout exiting from neighbouring packers) and core drillings

• Documentation: Recording of grout quantities, grouting pressure and grout propagation relative to the grout hole

10.6.2 Constituent materials

• Cement Cement has to meet the requirements of Austrian Standard ÖNORM EN 197-1 and/or Austrian Standard ÖNORM B 3327-1; for sulphate-resistant cement Austrian Standard ÖNORM B 3327-2 applies.

• Additives All products used as additives must meet the requirements of Austrian Standard ÖNORM B 3309 (AHWZ).

• Rock meal (filler) The filler must meet the requirements of Austrian Standard ÖNORM EN 12620. In the case of sulphate attack or a risk of sinter formation in drainage lines, the CaCO3

• Make-up water

content must be < 10 %.

Make-up water must meet the requirements of Austrian Standard ÖNORM EN 1008. • Admixtures

Grouting aids and, if necessary, stabilisers are to be used as admixtures. Admixtures must meet the requirements of Austrian Standard ÖNORM EN 934-2.

• Bentonite Bentonite must meet the requirements of German Standard DIN 4127.

If sintering is to be expected in drained tunnel structures, grout with a CaCO3 content of < 10 %, relative to the solid matter, is to be used. The use of cement consisting mainly of limestone is not permitted. The optimum binder to be used is CEM III/B cement or cement with an appropriate AHWZ value according to Austrian Standard ÖNORM B 3309. The percentage of CaCO3

In case of sulphate attack, C

in the binder must not exceed 5%.

3Afree

If necessary, grouting aids are to be added to the grout. cement is to be used in the binder.

10.6.3 Inspection and testing

Grout is to be tested daily and/or once a month according to Table 10/1 within the framework of pre-construction testing and conformity testing:

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Parameter Test method Limit Frequency Grout settling in 2 hours

DIN V 4126-100

3 % pre-construction test,

then daily Marsh time to be determined in pre-construction test Density

Uniaxial compressive strength (1 d, 7 d and 28 d) ÖNORM B 4452 to be specified by

design engineer pre-construction test,

then once a month

Erosion resistance (at compressive strength < 5 N/mm² after 28 days)

Annex A, ÖNORM B 4452 in a period of

28 days max. 5 % increase of flow rate

pre-construction test only

Chemical resistance (in special cases only)

same as in erosion test, but with test

liquid

If bentonite is used as a grout constituent, bentonite slurry produced especially for this purpose is to be tested for the following parameters both in the pre-construction test and every time a new lot is delivered (Table 10/2):

Test method Tolerances

Filtration water discharge at 7 bar in 7.5 min

DIN V 4126-100

± 20 %

Marsh time ± 2 s

Density ± 20 g/l

Liquid-flow limit (ball harp) ± 1 ball

Water absorption capacity DIN 18132 ± 20 %

10.7 Grout injections for rock improvement

If fault zones and/or yield zones are encountered during tunnel driving, subsequent consolidation of the surrounding rock mass may be necessary for certain tunnel structures (e.g. pressure tunnels) in order to ensure positive locking of the tunnel with the rock mass. Under certain conditions, the rock mass may have to be injected to diminish the discharge of water into the tunnel and to create an impermeable or less permeable structure. As far as possible, existing holes in the segments (e.g. for backfilling) should be used for injection bores.

It is important to bear in mind that the injection pressure results in loads (point loads or asymmetrical loads) being imposed on the segment rings. These loads must be taken into consideration in segment design, or otherwise maximum pressure values have to be specified.

Testing of injection equipment and injection slurry is to be performed according to It. 10.6.3 and/or agreed upon with injection specialists.

Table 10/1 Pre-construction testing of grout

Table 10/2 Pre-construction testing of bentonite

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11 GEOMETRICAL TOLERANCES OF THE SEGMENT

Tolerances are the allowable deviations of the actual dimensions of a structural component from its design dimensions. The definition of tolerances is necessary in order to achieve the highest possible level of accuracy, circularity (all curvatures in the cross section and the alignment of the tunnel) and quality of the finished tunnel. The tolerances described below are to be examined and specified on a project-specific basis by the design engineer, considering the computational and empirical analysis of the segment ring.

The individual tolerances are independent of each other, some of them are specified as a function of segment size.

The tolerances specified should not be unjustifiably “tight” in order not to drive costs up through exaggerated demands in terms of accuracy.

11.1 Segment geometry

Essentially, the segment geometry is described in terms of the reference dimensions indicated below.

Given the accuracy of formwork geometry, all reference dimensions relevant to segment tolerances are to be measured on the inside of the segment.

Typical reference dimensions are listed in Table 11/1.

Fig. 11-1 Reference dimensions relevant to segment tolerances

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Code Designation Description Influences/Effect

Ao Centre distances,

openings, assembly parts

Position and dimensions of openings and assembly parts Handling and installation

As Facing length Inner chord between the radial joints

Radius, curvature, interconnection

B Segment width Segment width(s) between the circumferential joints

Ring width, circumferential joint

Dg Gasket groove geometry

Depth (Dg-T) and width (Dg-B) of gasket grooves Sealing function

Dl Diagonal length Diagonal inner chord between segment corners, difference

Ring circumference, ring diameter, ring width, cross section, angular deviations

Fe Evenness of joints

Evenness of radial and circumferential joints (delta between highest and lowest point along any control line)

Quality of load transfer area (limited contact area)

and function of gaskets

Fk Joint conicity

Angular dimension of radial and circumferential joints deviating from orthogonal

angle

Quality of joints, segment geometry and function of

gaskets

Fv Joint interconnection Angular dimension of radial

joint relative to axis of segment ring


gaskets

Pp Plane parallelity Parallelity of radial and

circumferential joints relative to theoretical joint surface


gaskets

Ri Radius inside Inner radius Ring circumference, ring diameter and cross section

Td Segment thickness Radial distance between

outside and inside surface of the segment

Load-bearing capacity, cover to reinforcement, surface characteristics

Ul Circumferential length Developed outside surface

parallel to circumferential joint (extrados)

Ring circumference, ring diameter and cross section

Wa-F Angular deviation of joint conicity

Angle of joint conicity in axial direction



Wa-V Angular deviation, interconnection angle

Angle of joint interconnection in radial direction



Table 11/1 Definitions of typical reference dimensions for segment geometry

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11.2 Setting of tolerances

Tolerances are set to allow for the conditions of segment production and for factors of influence after production (during storage and transport, before installation in the tunnel).

A distinction is made between formwork tolerances and segment deformation tolerances.

The tolerances and parameters described below are to be examined and specified on a project-specific basis by the design engineer, considering the computational and empirical analysis of the segment ring.

11.2.1 Formwork tolerances

The precision of the moulds used has an influence on the precision of the segments produced. Formwork tolerances are therefore set and checked on a project-specific basis.

11.2.1.1 Tolerances of steel formwork

To guarantee the required tolerances, the moulds used for segment production are to be inspected and re-adjusted on a regular basis.

The range of tolerance for the reference dimensions indicated in Fig. 11/1 for high-precision steel moulds is between ± 0.1 and ± 0.3 mm at an ambient temperature of +18 C ± 2K and depends on the size of the individual segments.

11.2.1.2 Tolerances of concrete formwork

Concrete formwork is rarely used and primarily serves for the production of segments having to meet less demanding requirements in terms of serviceability.

The tolerances for concrete formwork are less stringent than those for steel formwork; for the reference dimensions shown in Fig. 11/1, they range between ± 0.3 and ± 1.0 mm at an ambient temperature of +18 C ± 2K and depend on the size of the individual segments.

11.2.2 Segment deformation tolerances

Segment deformation is influenced by temperature, shrinkage, creep, deadweight, storage, transport, installation and the production process itself. Therefore, the tolerances for segments must be more generous than those for formwork.

The extent of segment deformation depends on the segment geometry.

11.2.2.1 Influences of temperature, shrinkage and creep

Temperature differences and shrinkage have a significant impact on the geometrical parameters of the segments, whereas the influence of creep is negligible from the point of view of tolerances.

• Influence of temperature “dT”: Changes in segment length due to temperature fluctuations during production, storage, transport and installation are unavoidable. Depending on the application of the segment, a temperature range from -30°C to +45°C may have to be considered when fixing temperature-dependent tolerances. Thus, assuming a production temperature of +18°C, an effective temperature difference of dT = +27° and dT = -48° has to be taken into account for a possible expansion and/or shortening of the finished segment.

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• Shrinkage “dSw”: Shrinkage is calculated on the basis of Austrian Standard ÖNORM EN 1992-1-1. Essentially, the shrinkage value depends on the thickness of the segment, relative humidity and the age of the concrete (according to Fig. 8 and 9 of Austrian Standard ÖNORM EN 1992-1-1, concrete at the age of one year has reached approx. 60% to 70% of its final shrinkage value). A relative humidity of 70% is proposed for the determination of the shrinkage value.

11.2.2.2 Influences of deadweight during storage, transport and installation

Segment deformations due to the influence of deadweight “dEg” during storage, transport and installation have to be taken into consideration in the interpretation of control measurements.

Storage conditions and the age of concrete (modulus of elasticity) have a significant influence on deformation. Project-specific storage conditions have to be considered when setting the respective tolerances.

The deformations identified in the segments are elastic, which means that no significant changes in segment geometry resulting in installation problems are to be expected.

11.2.2.3 Production tolerances “dH”

Production tolerances are set to allow for the influence of temperature on formwork, deformation of moulds during segment production and mould wear and tear. The reference values indicated in Table 11/1 thus change in the course of production. Production tolerances must be set at least as high as the maximum formwork tolerances (see It. 11.2.1).

11.2.2.4 Determination of segment tolerances

The theoretical overall tolerance is the sum total of the individual tolerances mentioned above (see [equation 1]).

dL = dT + dSw + dH (+ dEg) [equation 1]

The overall tolerance to be observed must always be larger than the calculated theoretical overall tolerance (see [equation 2]):

GT > dL [equation 2]

in which:

dL sum total of deformations/distortions of a reference value (according to Table 11/1) dT deformation due to temperature dSw deformation due to shrinkage dH deformation due to production process dEg deformation due to deadweight (if summation is appropriate for total deformation) GT overall tolerance to be observed (for each reference dimension)

The overall tolerances are to be set for each individual project according to the above equation 2.

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11.2.3 Tolerances for segment details

11.2.3.1 Influences of connecting devices and joint design details

The positioning and size of connecting devices must be chosen with a view to the overall tolerances as well as the installation tolerances of the segments.

Holes for bolt connections must be larger than the bolt diameter by at least the allowable installation tolerance.

The diameter tolerance of dowel holes for dowel pins has to be set to suit the dowel to be used. The dowel positioning tolerance in the segment must compensate for the segment installation tolerance to permit the dowel to be inserted.

The groove for guide rails in the radial joint as well as coupling systems (groove-and- tongue and cam-and-socket systems) have to be produced to a tolerance of + 2 mm in dimension and position.

The positioning and installation tolerances of the segment must be allowed for in the design of connecting systems.

11.2.3.2 Influences of gaskets

The design of the segment gasket has to allow for the installation tolerance and the positioning tolerance of the groove base for the preformed gasket. The usual tolerances for the depth and width of the groove base are ± 0.5 to ± 1.0 mm. These values have to be chosen with reference to the segment sealing system used.

11.3 Measuring programme

The measuring programme provides for • measurements on the segment or • measurements on the segmental system (test ring) The following measuring methods can be applied: • manual measuring (use of measuring tapes, templates, etc.) • 3D measuring The measuring programme, including the measuring methods to be applied and the frequency of measurements, is to be specified by the design engineer. The detailed measuring sequence is to be proposed by the Contractor and agreed upon with the Owner (local construction supervision).

11.3.1 Manual measurements

Reference dimensions are usually checked by means of templates. As a rule, the templates are made of steel and have to be readjusted repeatedly in the course of quality control.

Additionally, calliper squares and precision measuring tapes are used.

11.3.2 3D measurements

3D measurements record a point cluster of the segment produced and calculate a theoretical “mean” segment on that basis, which is then compared with the ideal segment. The deviations have to be indicated.

This accurate measuring method (depending on the number of points) also has to be applied to segment moulds for the purposes of acceptance and regular quality control.

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11.3.3 Test ring

The test ring is used to measure the reference dimensions, on the one hand, and the system tolerances according to Chapter 12, on the other hand. Depending on the requirements of the system, the test ring may be either a single ring or a double ring. The bottom test ring is to be measured completely. If the results are not within the given tolerances, appropriate measures have to be taken to meet the quality requirements and, above all, to achieve the required level of serviceability.

The test ring is to be produced before the go-ahead is given for segment production. Further tests according to It. 11.3.4 are to be performed during production.

Sealed systems must be demonstrated to meet the tolerances in the closed ring, without the elastomer gasket in place, in order to avoid recovery forces.

Reference dimensions to be verified on the assembled test ring: • outer diameter (at least in 2 axes) • inner diameter (at least in 2 axes) • circumferential length of the segment system (to be measured in three planes) • joint opening • joint misalignment

11.3.4 Test frequencies

The individual segments have to be measured in the factory hall when the segments are ready for delivery to the outdoor storage area. The test frequency depends on the test object and the segmental system (Table 11/2). The measuring programme (dimensions), the means of testing (equipment, precision, calibration) and the scope of testing (test interval) have to be determined on a project-specific basis. Moveable formwork parts and/or formwork exposed to higher wear and tear are to be measured more often than stationary formwork parts (gasket groove, erector grip points, bolt pockets, etc.).

Test object Unsealed systems Sealed systems

System-relevant formwork parts

every mould before production is started,

after 100th segment, then after every 500th

every mould before production is started,

after 10 segment

th

Test ring

segment, then after every100th segment

before production is started, subsequent intervals according to

requirements

before production is started, subsequent intervals according to

requirements

Segments

every mould 1st - 10th segment every

segment, 11th - 500th segment every 50th

segment, subsequently every 250th

every mould

segment

1st - 10th segment every segment, from 11th segment every 50th

segment

If essential inadmissible deviations are detected, testing is to be restarted at the initial frequency according to Table 11/2.

Table 11/2 Examples of test frequencies for conformity testing

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12 IMPERFECTIONS AND SYSTEM TOLERANCES

Imperfections will always occur when the individual segments are assembled to form a segment ring and/or a segmental system. These imperfections are to be accommodated by the design and construction tolerances of the system.

It is important to note that system tolerances should not be unnecessarily “tight”, as exaggerated requirements in terms of accuracy would result in significant cost increases.

12.1 Design phase

12.1.1 Influences on the structural analysis The structural analysis of the segment ring for the prevailing rock and groundwater pressure yields the compressive forces acting on the segment ring and the design torsion angles as the most important parameters for the dimensioning of the radial joints.

Assuming the usual ground stiffness values, the design torsion angles (Fig. 12/2) mostly remain below 0.5% and therefore do not need to be considered in the calculation up to this limit.

12.1.2 Imperfections and eccentricities in the radial joint

The radial joint is exposed to loading due to inaccuracies of the segment as well as ring installation inaccuracies (e.g. misalignment and deviations from plane parallelity of the contact areas of adjacent segments).

12.1.3 Imperfections and eccentricities in the circumferential joint

The circumferential joint is also affected by inaccuracies of the segment as well as ring installation inaccuracies (e.g. ovalisation, misalignment and deviations from plane parallelity of the contact areas of adjacent segments, eccentric loading of the segments by the machine in the tailskin).

12.1.4 Interaction between connector – sealing strip – segment geometry

Contact between adjacent segments activates the recovery forces of the sealing strip, which tend to open the joint. These recovery forces have to be allowed for in the design and are to be absorbed by the connectors (generally on a temporary basis).

In segmental systems with gaskets, imperfections, misalignment and joint opening are only permissible to an extent that does not impair the sealing function.

In segmental systems without gaskets, greater imperfections are allowed.

Inaccuracies in segment geometry have to be allowed for in the verification of contact areas between adjacent segments.

12.1.5 Influences of deformations and tolerances

The undesirable torsion angles of the contact areas, e.g. due to production, assembly and annulus grouting (Fig. 12/1 and Fig. 12/2), are of great importance. The torsion angles “∆ϕ1” and/or “∆ϕ2” can be limited to values of significantly less than 0.3% though continuous and precise checking of the dimensions of the steel moulds and the finished segments.

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If individual installed segments deviate for the circular shape of the ring by “f”, this leads to a change of the torsion angles “∆ϕ1” and/or “∆ϕ2” and results in so-called ovalisation. Through careful assembly by means of the erector, these torsion angles can be kept below 0.5%.

Deviations in segment width by “∆b” result in an uneven distribution of longitudinal compressive stresses on account of high thrust forces and/or a gap in the radial joint. The effect of these inaccuracies depends on the segmental system, since: • sealed systems tolerate hardly any gap in the circumferential joint, whereas • unsealed systems allow a larger gap in the circumferential joint and are not significantly

affected by deviations in segment width. The difference of the dimensional deviations of the diametrical diagonals results in torsion and additional angular deviations. The influence of these deviations on the overall tolerance has to be evaluated in combination with all other tolerances.

Torsion angles due to the ovalisation of the segment tube are problematic. Problems may occur if grouting of the annulus results in an uneven pressure distribution around the circumference of the tube and the necessary bedding effect is not produced in time. Such phenomena not only increase the strain on the radial joints, but may also significantly affect the tightness of both radial and circumferential joints.

12.1.6 Influences due to storage and installation

During storage and installation, the segments and the entire ring are subject to different loads, with inaccuracies and eccentricities playing an essential role in the loading of individual segments. Such load cases must be allowed for in the design, and the segments have to be dimensioned accordingly.

The segment reinforcement is significantly influenced by the following:

• Positioning of supports for segment storage and the eccentricities thus caused. • Any eccentric pressure exerted by the thrust jacks on individual segments during tunnel driving. • Steering of the shield machine exerts pressure on different parts of the ring. These additional

loads must be taken into consideration in the analysis.

Fig. 12-1 Production tolerances of segments, Fig. 12-2 Effect of production tolerances of arch length, width and plane parallelity segments and their assembly in the joint [11] inaccuracies, torsion angle of the radial joint [11]

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12.2 Construction phase

Geometrically true segment production is the prerequisite for constraint-free installation of the segments. Allowable deviations are to be agreed on a project-specific basis.

12.2.1 Segment production

The production of segments within the allowable tolerances is guaranteed through the quality control system. After inspection, the segments are moved to the storage area.

12.2.2 Transport and storage

The segments are to be stored at the storage site or on temporary interim storage areas, as provided for in the planning documents.

12.2.3 Installation – ovalisiation

The ovalisation of tunnel linings assembled from pre-fabricated elements is a frequent phenomenon, which is mostly due to the following causes: • assembly (deadweight of the segments) and loading by the back-up system (construction-related

causes), • annulus grouting and uplift of the tunnel tube (causes related to the bedding of the segment ring) Ovalisation is considered to be unavoidable. The measure of ovalisation as an allowable deviation from the diameter is to be specified.

Project-specific tolerances are to be defined for the segment ring, relating to the allowable deviations from the torsion angle as well as deviations from arch length and ring width (Fig. 12/3). In sealed single-shell segmental linings, construction-related ovalisation normally is less pronounced on account of the bedding technology applied (grouting of annular gap), whereas unsealed systems (with backfill material blown into the annulus by means of compressed air) show a greater tendency towards ovalisation.

Fig. 12-3 Example of ovalisation of the tunnel cross section due to widening of torsion angles

[11]

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12.2.3.1 Construction-related causes

As a rule, ovalisation occurs during segment assembly (deadweight of segments). The causes are either construction-related (e.g. joint design) or due to yielding of joint connectors (e.g. bolt or pin connections).

In order to avoid construction-related ovalisation, a method of controlled ring assembly has to be applied. When determining the permissible tolerances for joint design and the corresponding connectors, the tolerances permissible for segment production must be taken as a basis for reference.

Self-guiding connectors and systems (e.g. guide rails and dowels) have been found to facilitate controlled assembly.

12.2.3.2 Bedding-related causes

Ovalisation of the segment ring may also occur if the ring is unevenly bedded in the backfill material in the annulus. Yielding and/or articulated segmental systems are particularly sensitive to uneven bedding, as their radial joints are subject to uncontrolled torsion and their circumferential joints tend towards misalignment.

Besides the negative impact of ovalisation on quality in general and on the rate of advance, the tightness of both radial and circumferential joints may be affected.

The type of connection between the individual rings, designed either as a toothed coupling system or a smooth joint, has a major impact on the tendency of the rings towards ovalisation. After a certain initial deformation (slip), the ovalisation of the tunnel cross section activates coupling of adjacent rings and increases the bending stiffness of the segment ring (Fig. 12/4). The magnitude of the coupling forces is directly related to the total deformation of the tunnel tube. The larger the total deformation, the greater the differences at the misaligned radial joints (Fig. 12/5).

12.2.4 Installation – misalignment

The maximum permissible joint misalignment depends on the system and its respective boundary conditions (e.g. allowable tolerance for joint design, connecting devices, geometry of sealing strips, etc.).

The usual order of magnitude in sealed single-shell systems is ± 0.5 cm (tolerance for tunnel diameters ranging from 3.0–8.0 m). The extent of misalignment is to be adjusted to the permissible misalignment of the sealing strip.

Fig. 12-4 Ovalisation of adjacent rings Fig. 12-5 Convergences of a segment ring (superelevated) [11] (superelevated) [11]

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In unsealed systems, many of which are double-shell systems with an inner lining made from in-situ concrete, the usual misalignment range is 10 – 50 mm (tolerance for tunnel diameters of 3.0 – 8.0 m).

12.2.5 Installation – open joint

Inaccurate installation may result in gaping of the circumferential joint. These inaccuracies, which are greater in (unsealed) systems without bolt connections than in (sealed) systems with bolt connections, may cause problems for the installation of subsequent segments and segment rings, as the inaccuracies tend to accumulate.

Usually, these imperfections in installation can be offset by joint inserts used to fill the gap. In extreme cases, corrective rings have to be installed in order to ensure continued correct installation of subsequent segments and segment rings.

12.3 Tolerances based on system requirements

Based on the requirements to be met by the segmental system, tolerances are set to ensure the inherent consistency of the system in geometric as well as structural and functional terms.

12.3.1 Geometric system consistency

Geometric system consistency is a prerequisite for the buildability of the system and its conflict-free execution. This includes, in particular, compliance with the geometric requirements regarding the main system dimensions and the coupling, connecting and fastening elements.

In general, geometric system consistency provides the frame of reference for the maximum tolerances. These tolerances, which apply in any case, will be reduced if special structural and/or functional requirements are to be met by the segmental system and call for tighter tolerances.

The relevant reference parameters are: circumferential length, inner radius, segment width, segment thickness, diagonal length, axial distances (openings, assembly parts), dimensions of fixed connecting systems (cam/socket, tongue/groove).

12.3.2 Structural system consistency

Structural system consistency ensures that the system can be built within the framework of its design concept.

12.3.2.1 Structural system consistency and segment tolerances

For segment tolerances, the requirements of structural system consistency mean that: • load-induced closure of the load-transferring joint must not result in harmful stress peaks

(compression of edges in case of angle deviation, stresses induced by limited contact areas due to unevenness),

• the differentiation between load-transferring contact areas and structurally stress-relieved areas (exposed surfaces, edges and ducts) must be maintained also if the permissible tolerances are fully utilised.

The essential reference parameters are: evenness of joints, angular deviation of joint conicity, angular deviation of joint interconnection.

12.3.2.2 Structural system consistency and ring assembly tolerances

For ring assembly tolerances, the requirements of structural system consistency mean that: • the distortion of joints (edge compression and eccentricity) allowed for in the structural design

must not be exceeded within the framework of the ring assembly tolerances, • the joint misalignment (eccentricity, limited contact areas) allowed for in the structural design

must not be exceeded within the framework of the ring assembly tolerances.

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The essential reference parameters are: ovality/joint distortion, joint misalignment, ring inclination (saw tooth).

12.3.3 Functional system consistency

To ensure achievement of the functional objectives of segmental systems, particular attention has to be paid to the following requirements:

12.3.3.1 Functional requirements to be met by systems with a gasket frame

In systems sealed by means of a gasket frame, compliance with segment and ring assembly tolerances is essential to ensure that the gaskets can fulfil their function in the joints. Of the total tolerance (compression, misalignment) allowed for in the gasket design, one quarter to one third is taken up by the segment, while the remainder is at the disposal of the finished segment ring.

The essential reference parameters are: all geometric main dimensions, all angular deviations, joint misalignment and ovality.

The tolerances essentially depend on the type and properties of the gasket frame (section, material, frame construction) and have to be determined on an individual basis.

12.3.3.2 Functional requirements to be met by unsealed systems or systems with mortar-filled joints

In unsealed systems or systems with mortar-filled joint, compliance with maximum allowable joint openings and joint misalignments is particularly important with a view to the possibility of subsequent joint sealing (mortar-filled joints).

The essential reference parameters are: joint misalignment, angular deviations of the joints, joint opening.

12.3.3.3 Functional requirements in terms of surface evenness (inner wall of segmental lining)

The segmental system has to meet certain requirements with a view to subsequent operations (e.g. evenness of base for waterproofing or surface friction).

For water transfer tunnels, flow resistance is an essential parameter (hydraulic roughness). Therefore, a higher tolerance is allowable in the radial joints (e.g. 30 mm) than in the circumferential joints. Mortar-sealing of joints has an influence on the allowable misalignment.

The essential reference parameters are: misalignment of radial joints, misalignment of circumferential joints.

12.3.3.4 Functional requirements to be met by the ring geometry

Compliance with ring assembly tolerances is essential also with a view to the required clearance profile, subsequent installation of an inner lining, etc.

The essential reference parameters are: ovality, joint misalignment.

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13 STANDARDS, GUIDELINES, BIBLIOGFAPHY

13.1 Standards referred to in the text

ÖNORM B 3100 Beurteilung der Alkali-Kieselsäure-Reaktivität im Beton; Ausgabe 08/08.

ÖNORM B 3131 Gesteinskörungen für Beton – Regeln zur Umsetzung der ÖNORM EN 12620; Ausgabe 10/06.

ÖNORM B 3303 Betonprüfung; Ausgabe 09/02. (Anmerkung: Ab Erscheinen der ONR 23303 gelten die entsprechenden Abschnitte der ONR).

ÖNORM B 3309 Aufbereitete hydraulisch wirksame Zusatzstoffe für die Betonherstellung (AHWZ); Ausgabe 02/04.

ÖNORM B 3327-1 Zemente gemäß ÖNORM EN 197-1 für besondere Verwendungen – Teil 1: Zusätzliche Anforderungen; Ausgabe 07/05.

ÖNORM B 3327-2 Zemente gemäß ÖNORM EN 197-1 für besondere Verwendungen – Teil 2: Erhöht sulfatbeständige Zemente; Ausgabe 09/01.

ÖNORM B 4452 Erd- und Grundbau – Dichtwände im Untergrund; Ausgabe 12/98.

ÖNORM B 4710-1 Beton – Teil 1: Festlegung, Herstellung, Verwendung und Konformitäts-nachweis (Regeln zur Umsetzung der ÖNORM EN 206-1 für Normal und Schwerbeton); Ausgabe 10/07.

ÖNORM EN 196-1 Prüfverfahren für Beton – Teil 1: Bestimmung der Festigkeit; Ausgabe 04/05.

ÖNORM EN 197-1 Zement – Teil 1: Zusammensetzung, Anforderungen und Konformitäts-kriterien von Normalzement; Ausgabe 10/08.

ÖNORM EN 450-1 Flugasche für Beton – Teil 1: Definition, Anforderungen und Konformitätskriterien; Ausgabe 08/05.

ÖNORM EN 450-2 Flugasche für Beton – Teil 2: Konformitätsbewertung; Ausgabe 08/05.

ÖNORM EN 934-2 Zusatzmittel für Beton, Mörtel und Einpressmörtel – Teil 2: Betonzusatz-mittel – Definitionen, Anforderungen, Konformität, Kennzeichnung und Beschriftung (konsolidierte Fassung); Ausgabe 03/06, Normentwurf 01/09.

ÖNORM EN 1008 Zugabewasser für Beton – Festlegungen für die Probenahme, Prüfung und Beurteilung der Eignung von Wasser, einschließlich der bei der Betonherstellung anfallendem Wasser, als Zugabewasser für Beton; Ausgabe 10/02.

ÖNORM EN 1097-3 Prüfverfahren für mechanische und physikalische Eigenschaften von Gesteinskörnungen – Teil 3: Bestimmung von Schüttdichte und Hohlraumgehalt; Ausgabe 08/09.

ÖNORM EN 1991-1-7 Eurocode 1 – Einwirkungen auf Tragwerke – Teil 1–7: Allgemeine Einwirkungen – Außergewöhnliche Einwirkungen; Ausgabe 04/07.

ÖNORM EN 1992-1-1 Eurocode 2 – Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken – Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau; Ausgabe 11/05.

ÖNORM EN 12350-5 Prüfung von Frischbeton – Teil 5: Ausbreitmaß; Ausgabe 04/00.

ÖNORM EN 12350-6 Prüfung von Frischbeton – Teil 6: Frischbetonrohdichte; Ausgabe 04/00.

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ÖNORM EN 12350-7 Prüfung von Frischbeton – Teil 7: Luftgehalte – Druckverfahren; Ausgabe 10/00.

ÖNORM EN 12620 Gesteinskörnungen für Beton; Ausgabe 09/08.

ÖNORM EN 13263-1 Silikatstaub für Beton – Teil 1: Definitionen, Anforderungen und Kon-formitätskriterien; Ausgabe 11/05; Änderung A1; Normentwurf 09/08.

ÖNORM EN 13263-2 Silikatstaub für Beton – Teil 2: Konformitätsbewertung; Ausgabe 11/05; Änderung A1; Normentwurf 10/08.

ÖNORM EN 13369 Allgemeine Regeln für Betonfertigteile; Ausgabe 05/08.

ÖNORM EN 13791 Bewertung der Druckfestigkeit von Beton in Bauwerken oder in Bau-werksteilen; Ausgabe 08/07.

ÖVE/ÖNORM EN ISO/IEC 17025 Allgemeine Anforderungen an die Kompetenz von Prüf- und Kalibrierungslaboratorien; Ausgabe 01/07 (konsolidierte Fassung).

DIN 4127 Erd- und Grundbau; Schlitzwandtone für stützende Flüssigkeiten; Anfor- derungen, Prüfverfahren, Lieferung, Güteüberwachung; Ausgabe 08/86.

DIN 18132 Baugrund, Versuche und Versuchsgeräte – Bestimmung des Wasserauf-nahmevermögens; Ausgabe 12/95.

DIN V 4126-100 Schlitzwände – Teil 100: Berechnung nach dem Konzept mit Teil-sicherheitsbeiwerten; Ausgabe 04/96.

13.2 Guidelines and regulations

ÖVBB-Richtlinie Sichtbeton – Geschalte Betonflächen; Gründruck 06/09.

ÖVBB-Richtlinie Innenschalenbeton; Ausgabe 10/03.

ÖVBB-Richtlinie Spritzbeton; Ausgabe 07/04.

ÖVBB-Richtlinie Erhöhter Brandschutz mit Beton für unterirdische Verkehrsbauwerke inkl. Sachstandsbericht „Brandeinwirkungen – Straße, Eisenbahn und U-Bahn; Ausgabe 07/05.

ÖVBB-Merkblatt Schutzschichten für den erhöhte Brandschutz für unterirdische Verkehrsbauwerke; Ausgabe 11/06.

ÖVBB-Richtlinie Erhaltung und Instandsetzung von Bauten aus Beton und Stahlbeton; Ausgabe 07/07.

ÖVBB-Richtlinie Faserbeton; Ausgabe 07/08.

RVS 09.01.42 Tunnel – Tunnelbau; Konstruktive Ausführung: Geschlossene Bauweise im Lockergestein unter Bebauung; Ausgabe 05/04, letzte Änderung 08/04.

RVS 09.01.43 Innenschalenbeton; Ausgabe 05/04; letzte Änderung 03/06.

RVS 09.01.45 Tunnel – Tunnelbau; Konstruktive Ausführung: Baulicher Brandschutz in Straßenverkehrsbauten; Ausgabe 09/06.

RVS 11.06.42 Qualitätssicherung Bau – Prüfungen: Beton, Nachbehandlungsmittel für Beton; Ausgabe 12/85.

ÖGG – Richtlinie Richtlinie für die geomechanische Planung von Untertagebauten mit zyklischen Vortrieb, 2. überarbeitete Auflage 2008.

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HL-Richtlinie Richtlinie für das Entwerfen von Bahnanlagen – Hochleistungsstrecken; Anlage 4: Baulicher Brandschutz in unterirdischen Verkehrsbauten von Eisenbahn-Hochleistungsstrecken; Ausgabe 10/04.

ASTM C 403 Standard-Test-Methode für die Einstellung der Beton-Mischungen durch Eindringwiderstand; Ausgabe 2008.

ATV-A161 Statische Berechnung von Vortriebsrohren, Herausgeber: Abwasser- technische Vereinigung e.V. /ATV); Ausgabe 01/90; Verlag: DWA, ISBN: 978-3-933693-32-7.

DAUB-Richtlinie Empfehlungen für statische Berechnungen von Schild-Vortriebs-Maschinen, Deutscher Ausschuss für unterirdisches Bauen – Arbeitskreis Schildstatik, Tunnel; Ausgabe 07/05.

TSI-SRT Richtlinie 96/48/EG über die Interoperabilität des transeuropäischen Hochgeschwindigkeitsbahnsystems, Teilbereich „Sicherheit in Eisen-bahntunneln“; Ausgabe 12/07.

13.3 Additional standards to be taken into consideration

ÖNORM B 1991-1-2 Eurocode 1 – Einwirkungen auf Tragwerke – Teil 1-2: Allgemeine Einwirkungen – Brandeinwirkungen auf Tragwerke – Nationale Festlegungen zu ÖNORM EN 1991-1-2; Ausgabe 12/03.

ÖNORM B 1991-1-7 Eurocode 1 – Einwirkungen auf Tragwerke – Teil 1–7: Allgemeine Einwirkungen – Außergewöhnliche Einwirkungen – Nationale Fest- legungen zu ÖNORM EN 1991-1-2; Ausgabe 04/07.

ÖNORM B 1992-1-1 Eurocode 2 – Bemessung und Konstruktion von Stahlbeton- und Spann-betontragwerken – Teil 1-1: Allgemeine Bemessungsregeln und Regeln für den Hochbau – Nationale Festlegungen zu ÖNORM EN 1992-1-1, nationale Erläuterungen und nationale Ergänzungen; Ausgabe 02/07.

ÖNORM B 1992-1-2 Eurocode 2: Bemessung und Konstruktion von Stahlbeton- und Spann-betontragwerken – Teil 1-2: Allgemeine Regeln – Tragwerksbemessung für den Brandfall – Nationale Festlegungen zur ÖNORM EN 1992-1-2 und nationale Erläuterungen; Ausgabe 04/07.

ÖNORM B 1992-2 Eurocode 2: Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken – Teil 2: Betonbrücken – Bemessungs- und Konstruktionsregeln – Nationale Festlegungen zu ÖNORM EN 192-2, nationale Erläuterungen und nationale Ergänzungen; Ausgabe 08/02.

ÖNORM B 2203-1 Untertagebauarbeiten – Werkvertragsnorm – Teil 1: Zyklischer Vortrieb; Ausgabe 12/01.

ÖNORM B 2203-2 Untertagebauarbeiten – Werkvertragsnorm – Teil 2: Kontinuierlicher Vortrieb; Ausgabe 01/05.

ÖNORM EN 1991-1-2 Eurocode 1 – Einwirkungen auf Tragwerke – Teil 1-2: Allgemeine Ein-wirkungen – Brandeinwirkungen auf Tragwerke; Ausgabe 05/03.

ÖNORM EN 1992-1-2 Eurocode 2: Bemessung und Konstruktion von Stahlbeton- und Spann-betontragwerken – Teil 1-2: Allgemeine Regeln – Tragwerksbemessung für den Brandfall; Ausgabe 02/07.

ÖNORM EN 1992-2 Eurocode 2: Bemessung und Konstruktion von Stahlbeton- und Spann-betontragwerken – Teil 2: Betonbrücken – Bemessungs- und Konstruk-tionsregeln; Ausgabe 09/07.

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ÖNORM EN 13501-1 Klassifizierung von Bauprodukten und Bauarten zu ihrem Brandverhalten – Teil 1: Klassifizierung mit den Ergebnissen aus den Prüfungen zum Brandverhalten von Bauprodukten; Ausgabe 05/07; Änderung A1: Normentwurf 12/07.

ÖNORM EN 13501-2 Klassifizierung von Bauprodukten und Bauarten zu ihrem Brandverhalten – Teil 2: Klassifizierung mit den Ergebnissen aus den Feuerwiderstandsprüfungen, mit Ausnahme von Lüftungsanlagen; Ausgabe 01/08; Änderung A1: Normentwurf 12/07.

13.4 Bibliography

[1] Schweiger, H.F.; Some remarks on 2-D-models for numerical simulation of Schuller, H.; Pöttler, R.: underground constructions with complex cross sections,

Computer Methods and Advances in Geomechanics, Yuan (ed.) 1997 Balkema Rotterdam.

[2] Meißner, H.: Empfehlungen des Arbeitskreises "Numerik in der Geotechnik" der Deutschen Gesellschaft für Erd- und Grundbau e.V., Geotechnik 14 (1991), S. 1-10

[3] Maidl, B.: Handbuch des Tunnel- und Stollenbaus, Band II, S.107ff.

[4] Muir Wood A. M.: The circular tunnel in elastic ground. Geotechnique 25. No. 1, (1975), S. 115–127.

[5] Leonhardt, F., Reimann, H.: Betongelenke. Versuchsbericht, Vorschläge zur Bemessung und konstruktiven Ausbildung; Deutscher Ausschuss für Stahlbeton (DAfStb), Heft 175, Beuth Verlag, Berlin 1965 (siehe auch in Der Bauingenieur 41 Heft 2 (1966)).

[6] Hestermann, U.: Eignungsprüfungen 4. Röhre Elbtunnel – Großversuche: Umsetzung der Ergebnisse in Planung und Konstruktion; Band 38, S. 108-112, Unterirdisches Bauen 2000: Heraus- forderungen und Entwicklungspotentiale, Tagungsband STUVA-Jahrestagung 1999 in Frankfurt/M. ISBN 3-87094-640-7.

[7] Janßen P.: Tragverhalten von Tunnelausbauten mit Gelenktübbings; Dissertation (Bericht-Nr.83-41/Prof. Duddeck) Technische Universität Braunschweig 1983.

[8] Winselmann, D.; Städing, A.; Aktuelle Berechnungsmethoden für Tunnelauskleidungen Holzhäuser, J.: Babendererde, S.; mit Tübbingen und deren verfahrens-

technische Voraussetzungen, Deutsche Gesellschaft für Geotechnik e.V. (DGGT), Baugrundtagung Hannover 2000.

[9] STUVA: Empfehlung für die Prüfung und den Einsatz von Dichtungsprofilen in Tübbingauskleidungen, Autorenteam STUVAtec; 2007 Studiengesellschaft für unterirdische Verkehrsanlagen e.V.

[10] Schneider, E.; Spiegl, M.: Convergency compatible support systems, Tunnels & Tunnelling International, June 2008.

[11] ÖVBB-Sachstandsbericht: Sachstandsbericht Tübbinge, Ausgabe 12/2005.

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Hefte der Schriftenreihe und Richtlinien sind bei der Geschäftsstelle der Österreichischen Vereinigung für Beton- und Bautechnik gegen Kostenersatz erhältlich.

VERÖFFENTLICHUNGEN DER ÖSTERREICHISCHEN VEREINIGUNG FÜR BETON- UND BAUTECHNIK

Richtlinien Guideline “Concrete Segmental Lining Systems” (Edition 2011) Richtlinie “Befahrbare Verkehrsflächen in Garagen und Parkdecks” (Ausgabe 2010) Merkblatt „Braune Wannen“ (Ausgabe 2010) Richtlinie “Erhaltung und Instandsetzung von Bauten aus Beton und Stahlbeton” (Ausgabe 2010) Richtlinie "Tunnelentwässerung“ (Ausgabe 2010) Richtlinie “Spritzbeton” (Ausgabe 2009) Merkblatt “Weiche Betone” (Ausgabe 2009) Richtlinie „Sichtbeton – Geschalte Betonflächen“ inkl. Gütezeichen „Fachbetrieb für Sichtbeton“ (Ausgabe 2009) Richtlinie “Schildvortrieb” (Ausgabe 2009) Richtlinie „Tübbingsysteme aus Beton“ (Ausgabe 2009) Richtlinie “Bewertung und Behebung von Fehlstellen bei Tunnelinnenschalen“ (Ausgabe 2009) Merkblatt “Beton für Kläranlagen” (Ausgabe 2009) Richtlinie "Wasserundurchlässige Betonbauwerke – Weiße Wannen" (Ausgabe 2009) Merkblatt “Herstellung von faserbewehrten monolithischen Betonplatten” (Ausgabe 2008) Richtlinie “Faserbeton” (Ausgabe 2008) Richtlinie “Injektionstechnik – Teil 1” (Ausgabe 2008) Richtlinie “Erhaltung und Instandsetzung von Bauten aus Beton und Stahlbeton” (Ausgabe 2007) Richtlinie “Konstruktive Stahleinbauteile in Beton und Stahlbeton” (Ausgabe 2006) Merkblatt “Schutzschichten für den erhöhten Brandschutz für unterirdische Verkehrsbauwerke” (Ausgabe 2006) Merkblatt “Kreisverkehre mit Betonfahrbahndecken” (Ausgabe 2006) Guideline “Inner Shell Concrete” (Edition 2006) Guideline “Sprayed Concrete” (Edition 2006) Richtlinie “Stahl-Beton-Verbundbrücke” - inkl. Musterstatik (Ausgabe 2006) Sachstandsbericht “Tübbinge” (Ausgabe 2005) Richtlinie “Erhöhter Brandschutz mit Beton für unterirdische Verkehrsbauwerke” inkl. Sachstandsbericht "Brandeinwirkungen - Straße, Eisenbahn, U-Bahn" (Ausgabe 2005) Merkblatt “Unterwasserbetonsohlen (UWBS)” (Ausgabe 2005) Richtlinie “Fugenausbildungen im Tunnel und Konstruktionsprinzipien am Übergang offene/geschlossene Bauweise” (Ausgabe 2005) Richtlinie “Bohrpfähle” (Ausgabe 2005) Merkblatt “Anstriche für Tunnelinnenschalen” (Ausgabe 2004) Richtlinie “Kathodischer Korrosionsschutz von Stahlbetonbauteilen” (Ausgabe 2003) Richtlinie “Innenschalenbeton” (Ausgabe 2003) Richtlinie "Nachträgliche Verstärkung von Betonbauwerken mit geklebter Bewehrung" (Ausgabe 2002)

Merkblatt "Selbstverdichtender Beton“ (SCC) (Ausgabe 2002) Richtlinie "Schmalwände" (Ausgabe 2002) Richtlinie "Dichte Schlitzwände" (Ausgabe 2002) Richtlinie "Bewehrungszeichnungen" (Ausgabe 2001) Richtlinie "LPV-Beton"(Ausgabe 1999) Merkblatt "Hochleistungsbeton" (Ausgabe 1999) Sachstandsbericht "Hochfester Beton" (Ausgabe 1993) Richtlinie "Frost-Tausalz-beständiger Beton" (Ausgabe 1989) Richtlinie für die Herstellung von Betonfahrbahndecken (Ausgabe 1986) Richtlinie für Herstellung und Verarbeitung von Fließbeton (Ausgabe 1977) Richtlinien für Leichtbeton, Teil 1-4 (Ausgabe 1974 - 1978) (Teile 1 und 4a sind durch ÖNORM B 4200-11 ersetzt) Schriftenreihe Heft 69/2010 Betontag 2010 Heft 68/2009 5th Central European Congress on Concrete Engineering “Innovative Concrete Technology in Practice” (inkl. CD) Heft 67/2008 Betontag 2008 Heft 66/2007 Österreichische Betonstraßentagung 2007 Heft 65/2007 Fortbildungsveranstaltung 2007 Sektion Spannbeton Heft 64/2006 Betontag 2006 Heft 63/2005 Fortbildungsveranstaltung 2005 Sektion Spannbeton Heft 62/2005 Internationale Fachtagung 2005 “Betondecken aus volkswirtschaftlicher Sicht” Heft 61/2005 1st Central European Congress on Concrete Engineering “Fibre Reinforced Concrete in Practice” (inkl. CD) Heft 60/2005 Einführung in die neue Richtlinie Bohrpfähle Heft 59/2005 Österreichische Betonstraßentagung 2005 Heft 58/2005 Vorgespannte Flachdecken mit Vorspannung ohne Verbund – freie Spanngliedlage Heft 57/2004 Einführung in die neue Richtlinie Kathodischer Korrosionsschutz Heft 56/2004 Österreichischer Betontag 2004 Heft 55/2003 Festvortrag Prof. Wladislaw Bartoszewski - Kulturelle Identität Mitteleuropas Heft 54/2003 32. FB Erdwärmenutzung aus erdberührten Betonteilen und in tiefliegenden Bauwerken Heft 53/2003 31. FB Innovative Betonkonstruktionen für den modernen Verkehrswegebau

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Hefte der Schriftenreihe und Richtlinien sind bei der Geschäftsstelle der Österreichischen Vereinigung für Beton- und Bautechnik gegen Kostenersatz erhältlich.

Heft 52/2003 30. FB Einführung in die neue Richtlinie Nachträgliche Verstärkung von Betonbauwerken mit geklebter Bewehrung Heft 51/2003 Betonstraßen Heft 50/2002 Festkolloquium anlässlich der Emeritierung von O.Univ.Prof. Manfred Wicke Heft 49/2002 29. FB Einführung in die neue Richtlinie Faserbeton Heft 48/2002 Österreichischer Betontag 2002 Heft 47/2001 28. FB Innovation im Betonbau Heft 46/2001 27. FB Einführung in die RL Bewehrungszeichnungen Heft 45/2000 26. FB Externe Vorspannung Heft 44/2000 25. FB Erfahrungen mit der RVS 8S.06.32 Deckenarbeiten - Betondecken, Deckenherstellung Heft 43/2000 Österreichischer Betontag 2000 Heft 42/1999 24. FB Einführung in die neue Richtlinie Dichte Schlitzwände Heft 41/1999 23. FB Qualitätsmanagement - Qualität miteinander? Baustellenorientiertes Qualitätswesen bei den Baustellen Heft 40/1999 22. FB Neue Normen und Technologien für Beton- und Spannbetonbauten Heft 39/1999 21. FB Einführung in die Richtlinie Qualitätssicherung für Instandsetzungsfachbetriebe und –produkte Heft 38/1999 20. FB Einführung in die Richtlinie BETON - Herstellung, Transport, Einbau, Gütenachweis Heft 37/1999 19. FB Einführung in die Richtlinie Wasserundurchlässige Betonbauwerke - Weiße Wannen Heft 36/1998 18. FB Einführung in die ÖNORM B 4452 Heft 35/1998 17. FB Einführung in die neue Richtlinie Spritzbeton Heft 34/1998 16. FB Verbundlose Vorspannung im Hochbau Heft 33/1998 Österreichischer Betontag 1998 Heft 32/1998 FIP 1998-Amsterdam Vorgespannter Beton in Österreich Heft 31/1997 15. FB Aktuelle Fragen des Spannbetons Heft 30/1997 14. FB Neue Betonzusatzmittel - Neuer Beton? Heft 29/1998 13. FB Gründungstechnik Heft 28/1997 12. FB Eisenbahnbrücken aus Spannbeton

Heft 27/1997 Österreichischer Betontag 1996 Heft 26/1996 Innbrücke Kufstein Heft 25/1996 11. Fortbildungsveranstaltung Heft 24/1996 Donaubrücke Tulln Heft 23/1995 10. Fortbildungsveranstaltung Heft 22/1994 Österreichischer Betontag 1994 Heft 21/1994 Eisenbahnumfahrung Innsbruck – Inntalbrücke Heft 20/1994 FIP 1994 – Washington Heft 19/1994 Spannbeton – Bewehrungstechnik Heft 18/1993 Die auf dem EUROCODE 2 basierenden neuen ÖNORMEN der Reihe B 4700 Heft 17/1992 Österreichischer Betontag 1992 Heft 16/1992 Umweltschutz – Brückenbau Heft 15/1992 Vorspannung ohne Verbund Heft 14/1990 Österreichischer Betontag 1990 Heft 13/1990 FIP 1990 – Hamburg Heft 12/1989 Vorspannung beim Bau der Neuen Bahn Heft 11/1988 Vorstellung der Richtlinie “Spitzbeton” Teil 1 – Anwendung Heft 10/1988 Verstärken von Betontragwerken durch Vorspannung Heft 9/1988 Vorträge am Österreichischen Betontag Heft 8/1987 Aktuelle Fragen des Spannbetons Heft 7/1987 Verbundlose Vorspannung Heft 6/1986 Vortrage am Österreichischen Betontag Heft 5/1986 Flexibilität im Massivbau, Verstärken und Verbreitern von Betontragwerken Heft 4/1986 Fédération Internationale de la Précontrainte; 10. Kongress 1986, New Delhi Heft 3/1985 Vorspannung im Hochbau, Entwicklung in der Ankertechnik Heft 2/1984 Eisenbahnbrücken aus Spannbeton, Projektsteuerung im Bauwesen Heft 1/1984 Aktuelle Fragen des Spritzbetons

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Documents

GL Concrete Segmental Lining System 2011 02