www.mageba.ch

Expansion Joints

High driving comfort and low noise emission.A simple system, without any moving parts.Due to its shock-absorbing characteristics, the impacton the bridge from traffic is reduced considerably.Anchoring tried and tested for many years as a sealedconnection.Easy and quick replacement of finger plates (within amatter of hours) thanks to modular design and simpleanchoring from above.Can accommodate movements of up to 800mm.Jointed arrangement also allows rotational (φy, φz) andvertical movements (ez),Resistant against environmental impacts such as ozone,oils, fuels, de-icing salt and temperature.

Features

Principle

The low-noise sliding finger joint that is easily installed and readily exchangeable

TENSA®FLEX type RC

The TENSA®FLEX sliding finger expansion joint is a flexiblemetal-elastomeric bonded system which consists of twoasymmetric parts. The cantilever fingers of the upper partare installed with a downward pre-tension and thereforeapply a permanent pressure to the opposing slidingsurface of the lower part. This allows horizontalmovements of the bridge to be facilitated. The flexiblearrangement of the system also reduces the effect ofloading (especially heavy traffic) on the bridge structure.

Mentue Bridge, Switzerland

TENSA®FLEX sliding finger joint

Type Movement Smin A B C D b1 b2mm mm mm Mm mm mm mm mm

RC 100 100 100 670 332 290 67 340 380RC 200 200 100 870 532 290 72 340 580RC 300 300 100 790 430 290 101 340 480RC 400 400 100 890 530 290 101 340 580RC 500 500 100 990 630 290 101 340 680RC 600 600 50 1’090 750 320 123 370 800RC 700 700 50 1’190 850 320 123 370 900RC 800 800 50 1’290 950 320 123 370 1’000

Product range with associated dimensions and permitted movements

2 Dimensions and construction detail

Bridge Abutment

DesignThe TENSA®FLEX sliding finger consists of two steel parts, each of which hasfingers that are vulcanised in elastomeric material. The cantilevered upperpart of the joint (male) is pre-tensioned and thus always remains in contactwith its counterpart (female). These plates are both secure and elastic, thanksto the flexibly-arranged anchors. For movements of up to 200mm, the systemcan be installed in such a way that the gap is always covered, keeping thedrainage channel free of debris. The expansion joint system is anchored ontoa specially prepared concrete subsurface, and is therefore easily replaceable.

1 Upper part (male)2 Lower part (female)3 Cantilever fingers are elastically

fixed to the subsurface. Smalllevel differences can thereforebe accommodated.

4 Elastomeric foil is laid across theentire surface. This prevents anywater from entering the structure.

5 Adhesive sealant (hot bitumen) toprotect bridge

6 Special end-surface treatment facilitates bond of bitumen sealant to the joint

7 Bitumen sealant8 Wearing course

8 6

25 3 4

71

Plan view Cross section (type RC 300 – RC 800)

Cross section (type RC 100 – RC 200)

Installation on bridges with longitudinal fall

Optimal watertightnessThe joint is sealed with a 5mm EPDM drainage channel. It is bolted andbonded to a fastening angle. Then a 1.4mm sealing foil is applied to the wholejoint area and secured with a special adhesive.

Additionally, both parts of the expansion joint apply pressure to the edges ofthe drainage channel, ensuring that the EPDM material stays in position andguaranteeing the watertightness of the joint. In order to enable routinemaintenance works, the structure can also be equipped with a cover plate withcleaning flap.

The cantilevered elements (male) of the upper part of the TENSA®FLEXsliding finger joint are vulcanised with a slight downwards inclination. In thisway a pre-tension is created when the upper part is mounted on the lower(female) part of the joint.

Pretensioned system

Product ideaThe TENSA®FLEX sliding finger joint was developed to reduce the impact oftraffic loading on the main bridge structure and to be easily installed andreplaced as necessary. It was also developed to minimise the noise generatedby traffic travelling over the joint. Its flexible and pre-tensioned arrangementalso accommodates vertical movements (eg. settlement) of the bridge whileensuring that the fingers will never protrude into the carriageway.

This development, incorporating the flexibility of the elastomeric material incombination with the durability and simplicity of a steel finger joint, and themodular design (which facilitates easy replacement of parts), has resulted inthe TENSA®FLEX sliding finger joint .

Unlike standard finger joint structures, the TENSA®FLEX sliding finger joint,thanks to its elastomeric characteristics, is a pre-tensioned and jointedarrangement.

This means that the cantilevering fingers of the joint, which are kept inconstant contact with the lower part of the joint by the pre-tension, will notprotrude above the carriageway surface. Furthermore, vertical structuremovements (eg. abutment settling or torsion) can be accommodated.

Thus the mageba TENSA®FLEX sliding finger joint does not constitute ahazard, even to snow-clearing vehicles.

Jointed design

Minimal noise generationAs there are no impacting or mechanically moving parts, the system is veryquiet under traffic. Comparative measurements carried out during the bridgerenovation of the Seez viaduct on the A3 motorway at Walenstadt (St Gallen,Switzerland) showed that the noise level was reduced by up to 18dBA throughthe installation of TENSA®FLEX sliding finger joint. Note: A noise levelreduction of 10dBA is perceived by the human ear as being half as noticeable.

Technical Design 3

Gap – half openGap – fully open horizontally installed bearing

Upper finger element (male)

Lower (support) part(at central position)

Lower (support) part(at fully open position)

Detail: Watertight sealing

Height differences Δ due to settlemnt of abutments etc can be accommodated

250mm

Bridge sealing Sealing foil

Δ

Finger joint with cover plate at sidewalk

Sliding finger joint in service

Anchoring systemsThere are two possibilities for anchoring the TENSA®FLEX sliding finger jointto a structure:

1. Plugged anchoring in concreteThe joint can be anchored directly to a concrete subsurface. The subsurfacemust be finished with a tolerance of ±1mm in order to allow installation offinger elements without further preparation of the subsurface. The slope of thesub-surface must match the joint’s predefined inclination. This method ofinstallation does not require a steel substructure, which may be susceptible tocorrosion. Furthermore, the development of rock pockets and trapped air inthe concrete is avoided, as the concrete is poured before the joint ispositioned. Holes for chemical anchors are drilled in the concrete, and thefinger plates are installed after the setting of the adhesive and positioning ofthe sealing foil. Chrome steel anchors can also be supplied.

2. Anchoring on a steel substructureIn order to reduce the time required for the initial installation of a Finger Joint,it can be delivered together with a steel substructure, and installed directly onthe bridge. The structure is then aligned, welded to reinforcement, and set inconcrete. If the steel substructure is initially installed without the Finger Joint,the Joint can later be bolted to the substructure in a matter of a few hours(approx. 3-4 hours for a 15m joint). It is also possible to produce these steelsubstructures from stainless steel.

4 Materials, Tests and Anchoring options

Materials and corrosion protectionMaterials:

- Basic structure is steel S235 JR / S355 J2G3 with 3.1 B certificates, completely covered with elastomer with a shore hardness of 70-75°.

- Anchoring by means of compound anchors or onto a steel sub-structure. Stainless steel can also be used.

Corrosion protection of cantilevering finger (of type RC 300 and above):- Sandblasting SA 3, zinc paint coating 100µm plus 2 surface coatings of

PU, thickness of each layer 100µm

Tests and Permits - Three complete system test specimens of the TENSA®FLEX sliding finger

joint of type RC 200 P and RC 500 R have passed copious tests. Theyremained damage free – even when exposed to loads of up to 128kN – eachwith 2 x 106 load repetitions and a 3.5Hz test frequency.

- Additionally, the system test specimens carried static loads of up to 300kNwithout damage.

- The TENSA®FLEX Sliding Finger joint is certified according to the Austrianstandard RVS 15.04.51 after passing all tests without defects. During thecertification process, the joint was subjected to roll-over tests with heavytraffic at various speeds. It is therefore suitable for installation on Austrianmotorways and other roads where top quality elements are required.

The TENSA®FLEX sliding finger joint has been widely used for many years.Its quality and durability are ensured by:

- qualified personnel with long-term experience- Process-orientated quality management system (ISO 9001 / EN 29001)- professional installation on the bridge

Lasting quality

Anchoring onto a substructure

Steel Substructure

Opposing upper and lower parts of joint

Sliding finger joint during testing

Modular installation

The TENSA®FLEX sliding finger joint can be easily and cost-effectivelyinstalled as follows on a new structure with asphalt wearing course andconcrete substructure::

1. Reinforcement and formworkThe reinforcement grid should be organised to allow the boring of anchorholes as necessary. The fastening angle for the drainage channel is installedin the formwork at the required height by the contractor.

2. Concreting and levellingThe concrete has to be placed to an accuracy of +/- 1mm.

3. Drilling using templateThe drilling jig is positioned and fixed with anchors.

4. Installation of drainage channelThe shim is removed from the fastening angle; then the EPDM-drain isaligned and secured across the joint. Finally, the sealing sheeting is laid andbonded across the drainage channel.

5. Installation of finger elementsFirst, the female lower part of the joint is installed and anchored, and theanchor holes filled with anti-corrosion sealant. Then the male upper part isinstalled in the same way.

6. Placing of mastic sealantAfter removal of the formwork, the gaps between the finger joint and asphaltare filled with hot bitumen sealant.

Installation

Installation using Mini-Fly-OverThe mageba TENSA®FLEX sliding finger joint can be installed with littledifficulty on roads with high traffic density, using “Mini-Flyover“ to bridge theconstruction area during peak hours. The work on the joint can then be carriedout in stages during off-peak hours. In this way, working hours can beadjusted to traffic requirements, and impacts on traffic can be practicallyeliminated.

Installation 5

Concrete reinforcement and shuttering

Levelling

Installation of drainage channel

Placing of finger elements

Placing of asphalt adjacent to jointUse of the “Mini-Fly Over” system during installation

6 Maintenance, Replacement and Ordering

Replacement: Quick and EasyThe Finger Joint elements are connected to the structure from above usingdrilled anchors. Therefore there is no monolithic connection with the concreteof the structure, as is the case with traditional systems. The joint parts aredesigned as wearing parts (with a finite life) and the concrete anchorage as ahigh-durability part. This means that the time and effort required for drillingduring the initial installation does not arise during replacement of elements.Replacement of this type of joint can be completed within a matter of hours.Single sections of joint, for example those subjected to heaviest traffic loading,can be replaced in the same way without difficulty. The neighbouring elementscan remain in service, thus the entire joint must not be replaced at once.

MaintenanceIn order to ensure optimal performance, the waterproof drainage channel(usually of 5mm thick EPDM) under the joint should be cleaned on a regularbasis (at least once a year). To do this, an edge section of the joint is removedand the joint flushed out. Under no circumstances should the joint be cleanedfrom above using a sharp object, as this could result in damage to thechannel.

mageba EPDM drains have proven their value after a decade of constant use.Thanks to their relatively heavy weight, they also significantly reducedownward emission of noise.

Important: Snow ploughs without protective strips can damage the elastomericsurface of TENSA®FLEX sliding finger joints.

Quotations and OrdersOur quotationTo provide you with a quotation we will need the following documents and details :

- Detailed drawings of the area where the joint is to be installed (bridge cross-section)

- Movement range incl. movement direction

Your orderIn addition to the information already supplied, the following documents are also necessary when placing an order :

- Layout drawing of the structure, services drawings, etc- Pre-setting values- Other specifics

mageba product range

Shock Absorbers- Hydraulic Shock

Absorbers- Spring Dampers

Expansion Joints- Single Gap Joints- Modular Expansion

Joints- Sliding Finger Joints- Cantilever Finger Joints- Mat Joints- Railway Joints- Architectural Joints

Bridge Bearings- Pot Bearings- Elastomeric Bearings- Earthquake Bearings- Spherical Bearings- Incremental Launch Bearings- Special Bearings- Rocker Bearings

Services- Inspections- Testing- Installations- Refurbishments- Cleaning- Remote monitoring

More information on mageba and our products can be found on www.mageba.ch.

Inspection of a sliding finger joint

Preparation for cleaning of joint

bridges linking people – worldwide®

mageba saSolistrasse 688180 BülachSwitzerlandTel.: +41-44-872 40 50Fax: +41-44-872 40 59info@mageba.ch

Version 2008.07

mageba Bridge Products Pvt. Ltd.Shanghai, ChinaTel.: +86-21-5740 7635Fax: +86-21-5740 7636info@mageba.cn

mageba Bridge Products (Pvt.) Ltd.Kolkata, IndiaTel.: +91-33-22900250 to -253Fax: +91-33-22900254info@mageba.in

mageba gmbhUslar, GermanyTel.: +49-5571-9256-0Fax: +49-5571-9256-56uslar@mageba.ch

mageba gmbh Fussach, AustriaTel.: +43-5578-75593Fax: +43-5578-73348oesterreich@mageba.ch

mageba saCugy VD, SwitzerlandTel.: +41-21-731-0710Fax: +41-21-731-0711suisse@mageba.ch

mageba gmbh Esslingen a.N., GermanyTel.: +49-711-758844-0Fax: +49-711-758844-56stuttgart@mageba.ch