Design and Construction of Metro Stations and Underground Structures

5/20/2018 Design and Construction of Metro Stations and Underground Structures

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November 2008Engineers Ireland

Geotechnical Society of Ireland

Engineers IrelandEngineers Ireland -- Geotechnical Society ofGeotechnical Society of

IrelandIreland

Design and Construction of MetroStations and Underground Structures to

Eurocode 7 - with Case Histories

David Beadman

Byrne Looby Partners


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ContentsContents

The Eurocodes and Eurocode 7

Jubilee Line, London North Greenwich Station

Jubilee Line, London Canary Wharf Station

Copenhagen Metro Eurocode 2

Copenhagen Metro Observational Method


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British StandardsBritish Standards


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TheThe EurocodesEurocodes and Eurocode 7and Eurocode 7


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Eurocode SuiteEurocode Suite

EN 1990 Eurocode: Basis of structural design

EN 1991 Eurocode 1: Actions on structures

EN 1992 Eurocode 2: Design of concrete structures

EN 1993 Eurocode 3: Design of steel structures

EN 1994 Eurocode 4: Design of composite steel and concrete structures

EN 1995 Eurocode 5: Design of timber structures

EN 1996 Eurocode 6: Design of masonry structures

EN 1997 Eurocode 7: Geotechnical design

EN 1998 Eurocode 8: Design of structures for earthquake resistance

EN 1999 Eurocode 9: Design of aluminium structures


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Structure of theStructure of the EurocodesEurocodes

EN 1990

EN 1991

EN 1992 EN 1993 EN 1994

EN 1995 EN 1996 EN 1999

EN 1998EN 1997

Actions onstructures

Design and detailing

Geotechnical

and Seismicdesign

Basis of

structural design


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a

b

cd

ef

aa NationalNational titletitle pagepage

bb NationalNational forewordforeword

cc ENEN titletitle pagepage

dd ENEN texttext

ee ENEN AnnexAnnex(es)(es)

ff NationalNational annexannex

National version of a EurocodeNational version of a Eurocode


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National Annex?National Annex?

The member states refinement of the CEN released

Eurocode to reflect its own national practices Values of Nationally Determined Parameters (NDPs)

The decisions where main text allows alternatives

The choice to adopt informative annexes Non-contradictory complementary information (NCCI)


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CIRIA C580CIRIA C580

Embedded retaining

walls guidance foreconomic design.

London 2003


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Eurocode 7Eurocode 7

Approved by

CEN on 23

April 2004.


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Release of Eurocode to BSI by CEN

Develop National Annex Modify Existing Standards

BSI Publish Eurocode with National Annex

2

Yea

rs

Coexistence of Eurocode with British

Standard

Withdrawal of British Standard

3

Years

ImplementationImplementation


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Operation and ApplicationOperation and Application

Principles

General statements and definitions for which there is

no alternative.

Requirements for analytical models for which noalternative is permitted

Principle clauses are identified with the letterP

The verb shall is used (meaning must)


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Operation and ApplicationOperation and Application

Application rules

Generally recognised rules which satisfy the

Principles, but alternative rules may be used.

Verbs should, may, can etc used


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ContentsContents

Section 1: General

Section 2: Basis of geotechnical design

Section 3: Geotechnical data

Section 4: Supervision of construction, monitoring and

maintenanceSection 5: Fill, dewatering, ground improvement and

reinforcement


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ContentsContents

Section 6: Spread foundations

Section 7: Pile foundations

Section 8: Anchorages

Section 9: Retaining structures

Section 10: Hydraulic failure

Section 11: Overall stability

Section 12: Embankments


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ContentsContents

Annex A: Recommended partial factors

Annex B-J: Supplementary information

EN1997-2 Performance and evaluation of field and

laboratory measurements


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November 2008 Engineers IrelandGeotechnical Society of Ireland

EurospeakEurospeak

Actions (c.f. Loads)

Permanent & Variable (c.f. Dead and Live)

Geotechnical action 1.5.2.1

Action transmitted to the structure by the ground, fill,standing water or ground-water


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EurospeakEurospeak 1.5.2.71.5.2.7

Resistance

capacity . to withstand actions without mechanical

failure e.g. resistance of the ground, bending resistance,

buckling resistance, tensile resistance

Norm

Standard EN Euro-Norm i.e. European Standard

Characteristic

The value of a parameter to be used in design; usually

the value of an action only likely to occur with a

probability of 0.02 per annum or a material property

likely to be achieved with a probability of 0.95.


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Calculations 2.4Calculations 2.4

Characteristic Values 2.4.5.2 (2)P

The characteristic value of a geotechnical parameter

shall be selected as a cautious estimate of the value

affecting the occurrence of the limit state.


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Soil ParametersSoil Parameters


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Ultimate Limit States 2.4.7Ultimate Limit States 2.4.7

Internal failure or excessive deformation of the structure

or structural elements, including e.g. footings, piles orbasement walls, in which the strength of structural

materials is significant in providing resistance (STR);


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Ultimate Limit States 2.4.7 (STR)Ultimate Limit States 2.4.7 (STR)


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Ultimate Limit States 2.4.7Ultimate Limit States 2.4.7

Failure or excessive deformation of the ground, in which the

strength of soil or rock is significant in providingresistance (GEO);

NOTE Limit state GEO is often critical to the sizing of

structural elements involved in foundations or retaining

structures and sometimes to the strength of structural

elements.


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Ultimate Limit States 2.4.7 (GEO)Ultimate Limit States 2.4.7 (GEO)


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Design Approach 1 2.4.7.3.4.2Design Approach 1 2.4.7.3.4.2

Check for a limit state of rupture or excessive deformation: Combination 1: A1 + M1 + R1

Combination 2: A2 + M2 + R1

(Except for the design of axially loaded piles and anchors.)


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Eurocode 7 Table A.3Eurocode 7 Table A.3


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Ground surfaces 9.3.2.2 (2)Ground surfaces 9.3.2.2 (2)

Ultimate limit state level of resisting ground lowered

by a, where a is, for normal levels of control:

10% of wall height for a cantilever or 10% of depth

below the lowest support, limited to a maximum of

0.5m

i.e. Overdig allowance


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Embedded retaining wallEmbedded retaining wall

Soil strength M(table A.4)

Combination 2 to determine toe depth (Geo) i.e. BS 8002 design

Surcharge x F equiv.

=1.3/1.0 (table A.3)

Include over-dig

Resulting section forces

(BM & SF) x F =1.0

(table A.3) Designvalues.

Soil stiffness 2(CIRIA C580)


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Soil strength M =1.0

(table A.4)

Combination 1 to determine section forces (Str) i.e.BS 8110 design

Surcharge x F equiv.=1.5/1.35 (table A.3)

Include over-dig

Resulting section forces

(BM & SF) x F =1.35

(table A.3) Designvalues.

Soil stiffness unfactored


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Soil strength unfactored

Serviceability loadcase to determine deflections

Surcharge unfactored

No over-dig

Soil stiffness unfactored


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Execution Standards 7.1(3)pExecution Standards 7.1(3)p

BS EN 1536:1999, Execution of

special geotechnical works -bored piles

BS EN 12063:2000, for sheet

pile walls,

BS EN 12699:2000, for

displacement piles.

BS EN 14199 for micro-piles.


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The Jubilee Line Extension, LondonThe Jubilee Line Extension, London

North Greenwich stationNorth Greenwich station


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North Greenwich StationNorth Greenwich Station

Large internal space

No internal slabs Temporary propping of

retaining walls difficult


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Box designed independently of any temporary works

London clay

Thames Gravel

Alluvium

Made Ground

30m

22m


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Difficult to build station around temporary props

London clay

Thames Gravel

Alluvium

Made Ground

N th G i h t tiN th G i h t ti


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Construction sequenceConstruction sequence

Install hard soft secant piles

London clay

Thames Gravel

Alluvium

Made Ground


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Excavate outside box to 3m depth

Excavate inside to 7.5m depth

Install ground anchors

London clay

Thames Gravel

Alluvium

Made Ground


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Excavate to 15.5m depth

Install prop

London clay

Thames Gravel

Alluvium

Made Ground


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Complete excavation

London clay

Thames Gravel

Alluvium

Made Ground


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Open excavation with

ground anchors

Construction of box

avoided building around

props


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Analysed with WALLAP (beam-on-springs program)

Prop load 1500kN/m (unfactored) i.e 9000kN/prop @ 6m Measured typically 6000kN, one prop 15000kN (2500kN/m)

Note mismatch of stiffnesses - ground anchors and props

London clay

Thames Gravel

Alluvium

Made Ground


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Analysis now with factored

soils, overdig, softening,minimum fluid pressure

(i.e. in accordance with

Eurocode 7 and CIRIA

C580)

Wall is not stable


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The Jubilee Line Extension, LondonThe Jubilee Line Extension, London

Canary Wharf stationCanary Wharf station


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Canary Wharf stationCanary Wharf station

Diaphragm walls

installed from the

base of an old dock

i


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Diaphragm wallsDiaphragm walls

Dug under

bentonite using a

Grab orHydrofraise

Insertreinforcement

cage and concrete

using tremie pipe

Di h llDi h ll


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Diaphragm wallsDiaphragm walls

Typical joint detail.

Straight panels, tee

panels or corner panels.

Grab length 2.8m

typical.

Di h W llDi h W ll


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Diaphragm WallsDiaphragm Walls

Reinforcement details: Allow for the tremie pipe;

Allow for the unreinforced

area close to the CWS stopend;

For installation, the cage must

be lifted.

C Wh f t tiC Wh f t ti l t t bilitl t t bilit


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Canary Wharf stationCanary Wharf station slot stabilityslot stability


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The Copenhagen MetroThe Copenhagen Metro

Eurocode 2Eurocode 2

C h M tC h M t E d 2E d 2


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Copenhagen MetroCopenhagen Metro -- Eurocode 2Eurocode 2

Rules for Buildings

Piles require some

special attention for

buildability

Copenhagen MetroCopenhagen Metro -- Eurocode 2Eurocode 2


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November 2008

Engineers Ireland


Copenhagen MetroCopenhagen Metro Eurocode 2Eurocode 2

Analysis

programsunavailable

Spreadsheets

written and

checked

C i f S 400 S ifi i


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Comparison of BS5400 and the Metro SpecificationComparison of BS5400 and the Metro Specification

0.2mm0.25mmMaximum crack width

90mm75mmMinimum cover for structures cast against

the ground

50mm35mmMinimum cover for durability for

retaining wall members, as concrete castin non-aggressive ground

fck

=30N/mm2fcu

=35N/mm2Concrete grade

100 years120 yearsDesign life

Metro

Specification

BS5400Requirements

T d iT d t ti


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Stage 1 Install

retaining wall

Stage 2 Excavate

and construct roof

Stage3 Excavate and

construct waling beam

Stage 4 Excavate to

formation level

Top down construction sequenceTop down construction sequence

Station crossStation cross--sectionsection


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Station crossStation cross--sectionsection

Structure hung from roof

Large fixed-end moments

CrackCrack--width for concrete sectionswidth for concrete sections


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CrackCrack--width for concrete sectionswidth for concrete sections

Calculate crack width at cover required for durability

Eurocode 2Eurocode 2 -- Crack width calculationCrack width calculation


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Eurocode 2Eurocode 2 - Crack width calculationCrack width calculation

Eurocode 2Eurocode 2 -- Lapping of barsLapping of bars


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Eurocode 2Eurocode 2 Lapping of barsLapping of bars

Principle not permitted to lap bars greater than 32mm

diameter. (Not satisfied)

E d 2E d 2 E i l t di t f b b dlE i l t di t f b b dl


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Bundles of equivalent diameter greater than 55mm notpermitted (Application Rule)

Eurocode 2Eurocode 2 -- Equivalent diameter of bar bundlesEquivalent diameter of bar bundles

Bundles to be considered as notional bars for purposesof crack-width calculation (Application Rule)

E d 2E d 2 E i l t di t f b b dlE i l t di t f b b dl


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Equivalent perimeter of bundle = 40 x (2 + ) = 206mm

Number of bars in bundle:

(Assume 40mm diameter bars)

Two:

Equivalent diameter of a

single bar =

56mm

Perimeter of equivalent bar = 56.6 x = 178mm


E d 2E d 2 E i l di f b b dlE i l t di t f b b dl


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Equivalent perimeter of bundle = 40 x (3 + ) = 246mm

Number of bars in bundle:(Assume 40mm diameter bars)

Three:

Equivalent diameter of a

single bar =

69.3mm

Perimeter of equivalent bar = 69.3 x = 218mm


Circular sectionsCircular sections shear capacityshear capacity


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p yp y

Feltham I, The StructuralEngineer, June 2004


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The Copenhagen MetroThe Copenhagen MetroThe observational method atThe observational method at

Norreport stationNorreport station


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The Copenhagen MetroThe Copenhagen MetroThe observational method atThe observational method at

Norreport stationNorreport station

Description of the project.

Construction sequence

and the observational

method.

Application

Results

The Copenhagen MetroThe Copenhagen Metro


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Route of the Metro

Above ground

works, on

embankment orviaduct.

ChallengesChallenges


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100 year design life -0.2mm crackwidth limit.

Design to Eurocodes.

First significant deepbasement construction in

Copenhagen.

Environmental

standards.

Programme constraints.

Architectural

requirements.

Architectural challengesArchitectural challenges


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Natural light available atplatform level.

No internal columns at platform

level.

Minimal internal propping.

Danish minimalist design details.

Retaining wall detailsRetaining wall details


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Ground Conditions:

Made ground

Glacial till

Limestone

TBMTBM ProgrammeProgramme


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Islands Brygge

Ved Stadsgraven

Islands Brygge

Ved Stadsgraven



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Ved Stadsgraven

Islands Brygge

Havnegade

Ved Stadsgraven

Christianshavn StationChristianshavn Station


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Bottom up

construction

sequence with

temporary

props



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Havnegade

Islands Brygge

Ved Stadsgraven

Medieval BridgeMedieval Bridge


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Norreport StationNorreport Station -- BridgeBridge

FoundationsFoundations


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Medieval BridgeMedieval Bridge


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Application of the observationalApplication of the observational

techniquetechnique

Observation method managementObservation method management


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Settlement control

engineer

Comet

Retaining wall

designer

Bachy Soletanche

Permanent works

designer

Maunsell

Clients

representative

Cowi

Temporary works

designer

Carillion

Design managerComet

Site managerComet


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Excavation down to Waling BeamExcavation down to Waling Beam


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November 2008

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Excavation down to Base SlabExcavation down to Base Slab


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EurocodesEurocodes


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Documents

Design and Construction of Metro Stations and Underground Structures