Hilti solutions for post-installed rebar connections

Simply connected.

Hilti. Outperform. Outlast.

Hilti HIT is used to post-install about 35,000 km of rebar around the world every year.

Hilti solutions for post-installed rebar connections

Simply qualified.By Konrad Bergmeister

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The corresponding building codes are applied to the design of reinforced concrete structures. These codes, however, don’t cover the use of post-installed reinforcement, therefore approvals and regulations have a significant role to play in filling this gap.

These approvals prequalify injectable adhesive mortar systems for use in post-installing rebar connections. These are designed in accordance with existing building codes. A good example of this is the European Technical Approval (ETA) for rebar, which allows the design of post-installed rebar connections in concrete, using approved products in accordance with Eurocode 2 (EC 2).

Approvals are necessaryDesign Engineers can now adhere to the familiar rules laid down in these obligatory building codes when designing post-installed rebar connections. This is greatly facilitated by the use of products with the relevant approval, for example in Europe, it is ETA approval.These approvals are necessary to confirm the suitability of an injectable adhesive mortar system, covering its compliance with existing building codes and its ability to meet the design requirements for the structure concerned.The correct tools and accessories, as well as technical expertise are essential where concrete connections are to be made using post-installed rebar.

Dr. Konrad Bergmeister is Head of the Department of Structural Engineering at the University of Life Science and Natural Resources in Vienna, Austria. He has over 20 years experience in the field of structural engineering and design and has led many major infrastructure projects. The main topics of his research work are fastening systems, structural analysis, monitoring and maintenance.

By Prof. Dr. Ing.

This includes rebar detection devices, dependable drilling machines, suitably matched cleaning and injection accessories, comprehensive instructions and documentation of the processes and, last but by no means least, proper training of the applicable personnel. This is necessary to ensure high reliability of the fastening solution over the entire life of the structure. Design Engineers should rely on manufacturers or suppliers that provide complete system solutions. These systems are suitable injectable adhesive mortars for the post-installation of rebar connections in conformance with regulations – systems that have been approved for this application.

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be installed entirely independently of the concrete formwork and allow greater flexibility in the construction schedule and planning.

Simply more flexibleGreat flexibility is indispensable in today’s construction industry. Due to tight schedules, the planning process often overlaps with the actual execution of the work. Despite this, thanks to the ease with which post-installed rebars can be

The Hilti HIT system is the ideal solution for all kinds of post-installed rebar connections in conversion work, retro-fitting or the construction of new structures.

The Hilti HIT system is a simple, highly efficient and flexible solution for installing rebar connections that are as secure and reliable as cast-in reinforcement. However, in contrast to cast-in reinforcement, these connections can

Simply like cast-in.

The diagram clearly illustrates the effectiveness of Hilti HIT fast-cure and slow-cure injectable mortars compared to other systems.

With the Hilti systems, loads are taken up evenly by the concrete, without stress peaks and thus transferred optimally to the existing reinforcement. The load transfer values achieved by Hilti HIT are therefore comparable to those obtained with cast-in reinforcement.

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Depth of embedment (mm)

Cast-in rebar

Hilti HIT slow cure mortar

Hilti HIT fast cure mortar

Rigid epoxy resin mortar

integrated in the structure using the Hilti HIT system, deadlines can still be met.The Hilti HIT system lets you place rebar connections precisely where planned.

Complex and costly remedial work, structural alterations due to incorrectly positioned reinforcement or as a result of changes made to plans, all become a thing of the past.

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Simply more experience.By Jakob Kunz

When Hilti introduced the injection technique to the construction industry in the early 1980’s1), this innovation made the installation of rebars in deep holes much easier than with the methods usually applied at that time. As use of the technique and its associated technologies spread around the world, safe design methods were required. Research work carried out at the Swiss Federal Institute of Technology in Zurich2) resulted in publication of the first application-specific design brochure in 19943). Further research, especially at the University of Stuttgart4), led to the issue of general construction authority approvals for this technique, beginning in the year 20005). These approvals allow post-installed reinforcement to be designed like cast-in bars, in accordance with Eurocode 26). However, in practice, some cases occur where standard solutions with straight bars are not feasible, e.g. in thin walls or with frame node connections.

Hilti has therefore continued this research work. In co-operation with the Technical University of Munich7) and the American University of Beirut8), strut-and-tie models for special cases have been developed and tested successfully.

1) German Patent DE3247 227 “Verankerungsmittel” Application Date 21.12.1982

2) Marti, P.: Anchoring of Concrete Reinforcement using HIT-HY 150. Report no. 93.327-1, ETH Zürich, 1993.

3) Fastening Technology Manual B2.2. Hilti Corporation, Liechtenstein, 1994.

4) Spieth, H.A.: Tragverhalten und Bemessung von eingemörtelten Bewehrungsstäben. Dissertation, Universität Stuttgart, 2002

5) DIBt: Post-installed reinforcing bar connections made with Hilti HIT-HY 150 injection adhesive; General construction supervisory authority approval Z 21.8-1648, 22.11.2000.

6) ETA Technical Report TR 023 : Assessment of post-installed rebar connections, Edition November 2006

7) Kupfer H. et al: Nachträglich verankerte gerade Bewehrungsstäbe bei Rahmenknoten. Bauingenieur, Springer Verlag 2003

8) Hamad, B.S. et al.: Evaluation of Bond Strength of Bonded-In or Post-Installed Reinforcement. ACI Structural Journal Vol 103, No. 2. Farmington Hills, 2006.

Dr. Jakob Kunz is the Scientific Consultant for the Hilti Anchor Business Unit. He gained his doctorate at the ETH (Swiss Federal Institute of Technology) in Zurich and Lausanne and has been with Hilti as a Research Engineer, Project Manager and Chief Scientific Officer since 1989. Dr. Jakob Kunz specialises in the fields of fastening technology and reinforced concrete design. He is a member of fib, IABSE and SIA 179.

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In standard applications, such as for walls, slabs, beams, foundations, supporting columns and other concrete connections, post-installed rebar connections made using the Hilti HIT system can be considered equal to those incorporating cast-in reinforcing bars. To you, as a Design Engineer, this means that you have no additional planning or design work. Your design will comply with the building codes.

Even under special conditions, where a setting depth in accordance with approval regulations cannot be reached (e.g. due to the thickness of concrete), the high bond strength achieved with Hilti HIT injection mortar allows bars to be set at reduced depth. The necessary design work can be carried out easily with the aid of Hilti PROFIS Rebar.

Design at your fingertipsHilti PROFIS Rebar is a new PC application that makes the calculation

Simply designed.With Hilti PROFIS Rebar

of rebar overlap lengths and embedment depths easier than ever before – it quite simply puts the design of post-installed rebar connections at your fingertips. Hilti PROFIS Rebar designs concrete connections in accordance with Eurocode 2 (EC 2) using products prequalified by European Technical Approval (ETA). Furthermore, the higher bond strength offered by Hilti HIT injection mortars and the Hilti design method even allow designers to go beyond the requirements of the code.

Advantages of Hilti PROFIS Rebar

• Comprehensiverangeoftemplatesfor the design of concrete-to-concrete connections

• Alldesign-relevantdatacanbeenteredand altered directly on the 3D graphics model

• Allrelevanttechnicaldataandinstallation instructions can be printed out in the form of detailed, clearly structured reports

The current version of Hilti PROFIS Rebar can be downloaded from www.hilti.co.uk/rebar

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Simply more support.Hilti services for specifiers

Technical adviceHilti’s qualified engineers and technicians provide consulting, support and advice free-of-charge. They will be pleased to offer advice and answer any questions on the subject of post-installed rebar connections, wherever it suits you best – on the phone, at your office or on-site.

Anchor Fastening Technology Manual This technical manual provides a wealth of information on rebar connection design and many practical examples of post-installed rebar connections, as well as all the technical data for the Hilti HIT system for your easy reference.

User training*By providing special training, Hilti ensures that rebar installation personnel know how to use the HIT system, in accordance with the proper procedures so that post-installed rebar connections can be made correctly.

Pull-out tests*With a view to ensuring achievement of the required design load values, Hilti offers the possibility of carrying out on-site rebar pull-out tests.

Rebar analysisThe Hilti PS 200 Ferroscan system provides information about existing reinforcement by determining its position, diameter and depth of coverage without need for destructive procedures, such as removal of concrete.

The system’s PC application simplifies the job of analysing the data obtained and can be downloaded from: www.hilti.co.uk/ferroscan

Specification text examples*Examples of specification texts that are suitable for use in contract tenders can be downloaded free-of-charge from: www.hilti.co.uk/rebar

The Ferroscan PC application shows the position of transverse and longitudinal reinforcement clearly.

* Contact Technical Advisory Service on: (GB) 0161 886 1144 (IRL) 1850 287 387.

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Simply the best solution. Concrete + concrete = Hilti HIT system

Madrid Highway, Spain

The roadway slab of the M-30 highway in Madrid consists of reinforced concrete sections spanning a width of 13.80 m, with a thickness of 60 cm and a length of 2 m.

These are fastened by way of post-installed rebar connections at each side of the tunnel made by injecting Hilti HIT-RE 500 adhesive mortar into holes drilled in the concrete sections of the tunnel wall (bars of 30 - 32 mm diameter set at a depth of 400 mm).

These connections were designed in accordance with the ETAG European Technical Approval Guidelines using Hilti PROFIS.

Fire resistance tested in accordance with

HIT injectable mortar Hilti HIT-RE 500Hilti HIT-HY 150 MAX

Permissible rebar diameter range 8 – 25 mm dia. 8 – 40 mm dia.

-10°C – 40°C (-5°C*) 5°C – 40°C

180 min – 2 min (240 min) 120 min – 12 min

12 h – 30 min 72 h – 4 h

ETA-08/0202 ETA-08/0105

Z-21.8-1790

Suitable for water-filled holes and underwater application

European Technical Approval (ETA)

Suitable for use on dry and water- saturated concrete

Maximum permissible depth of embedment

Temperature of base material

Working time

Curing time

2 m 3.2 m

Yes Yes

3884/8246 (IBMB Braunschweig)

3357/0550-5 (IBMB Braunschweig)

WF 166402 (Warringtonfire)

WF 166402 (Warringtonfire)

No Yes

DIBt approval

* Reduced load values at base material temperatures of 5°C to -5°C are listed in the Hilti Anchor Fastening Technology Manual (FTM).

Choose the quickest and at the same time, most cost-efficient Hilti HIT solution – for post-installed connections that hold just like cast-in rebar.

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ø25

ø40

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Hilti HIT-RE 500Long working time, slow curingDepth of embedment up to 320 cm

Reducedload values

Hilti HIT-HY 150 MAXShort working time, rapid curingDepth of embedment up to 200 cm

YesNo

YesYes

Drilling method: - hammer drilling - diamond drilling

ETA-08/0202ETA-08/0105

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Simply approved. The Hilti HIT system for professional installations

Hilti HIT-RE 500 and HIT-HY 150 MAX injectable mortars have been awarded ETA approval for use in post-installed rebar connections. The stringent approval requirements qualify the mortars for use in applications where connections are designed in accordance with Eurocode 2 (EC 2).

No matter which of the two Hilti HIT injectable mortars a Design Engineer selects according to its suitability for the application, the reliability of its bonding characteristics or its compliance with building codes is never in doubt because the system has been prequalified through approval. Current design methods in accordance with the applicable building codes, in this case EC 2 - can be applied.

Simply reliable.In order to ensure secure rebar connections, compliant with approval requirements, the right preparations, carried out as specified, are essential.

This is why the use of suitable system accessories forms a decisive part of the approval requirements. A secure bond over the entire depth of the hole can be achieved only when the holes have been cleaned out correctly and the mortar injected without trapping air. Hilti supplies all the necessary tools and accessories for easy installation of rebar connections in compliance with approval requirements.

• Manual,cordlesselectricandpneumatic dispensers suitable for large or small-scale use and at various hole depths

• HiltiHITcartridgesintheappropriatesizes

• HiltiHITProfiRebarsetscontainingeverything necessary for a professional job: air nozzles, blow-out pumps, wire brushes, injection plugs and other accessories needed for cleaning the holes and injecting the mortar – all packed conveniently in a practical toolbox.

Use of these accessories is demonstrated during HIT training for installation personnel.

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Everything you need for fast, easy and reliable post-installed rebar.

Detection

Ferroscan PS 200 for the detection of reinforcing bars in concrete. Reduces the risk of hitting rebars when drilling. Provides accurate localisation, depth and diameter of rebar.

Design

Hilti PROFIS Rebar puts post-installed rebar connection design and the calculation of overlap and anchorage lengths at your fingertips.

Cutting

Hilti angle grinders featuring Smart Power and Hilti AC-D cutting discs for cutting rebars to length. Alternatively, use Hilti cordless reciprocating saws for total mobility.

Setting

Make a quick, easy, professional job of post-installed rebar connections – with Hilti HIT injectable mortars and efficient Hilti dispensers.

Cleaning

Hilti HIT Profi Rebar sets keep all the required cleaning accessories conveniently at hand.

Drilling

Drill faster and safer with Hilti combihammers and extra-rugged hammer drill bits, or with Hilti diamond core drilling systems.

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Hilti solutions for post-installed rebar connections

More than 100,000 satisfied customers benefit every year from our 25 years of experience.

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Hilti (Gt. Britain) Limited | 1 Trafford Wharf Road | Trafford Park | Manchester | M17 1BYFreephone: 0800 886 100 | Freefax: 0800 886 200 | www.hilti.co.uk

Hilti (Fastening Systems) Limited l Unit C4 l North City Business Park l Finglas l Dublin 11CallSave: 1-850-287-387 l Freefax: 1-800-654-600 l www.hilti.ie

Hilti. Outperform. Outlast.

3461644 March 2010