There has been a bridge at Walton on Thames since 1750, providing an important link across the River Thames between Shepperton and Walton on Thames.
This new £32.4 million bridge is the sixth bridge is under construction, with previous bridges, dating back to 1750, having been dismantled and rebuilt as traffic evolved and increased over time. It will replace two existing temporary bridges, and a new viaduct will be built alongside the existing viaduct, with the existing viaduct remaining in use for pedestrians, cyclists and horse riders.
After extensive preparatory work in 2011, the main construction works began in early January 2012 and building is expected to finish by the summer of 2013.
Surrey County Council appointed engineers Atkins and main contractor Costain Limited, who then asked Freyssinet to supply the bridge bearings. In total, 12 no. pot bearings were supplied through Freyssinet Products Company (FPC) in France. The bridge bearings comprised a mixture of fixed, free sliding and guided sliding types.
All of the bridge bearings supplied are CE marked, demonstrating conformity with the essential requirements of applicable EC directives. Freyssinet conducts a policy of permanently improving its products and research and development of new processes or materials. The rigorous product quality control practices Freyssinet has developed have enabled the Group to obtain CE marking to distribute its bridge bearings.
The main decks of the bridge are now being prepared for installation and once this is complete the temporary protection in the river will be removed at the end January of 2013. Overall the project remains on target for completion during summer 2013.
FREYSSINET SUPPLY BESPOKE BEARINGS FOR LEADENHALL BUILDING
The Leadenhall Building is a 47 storey, 225 metre (737 ft) tall skyscraper, designed by Richard Rogers, which is currently under construction in London. With its distinctive wedge-shaped profile, it is informally referred to as the Cheese Grater and is set to become one of the tallest buildings in the City of London. The development is expected to cost approximately £286 million in total.
In 2007-8, the existing building on the site was demolished in preparation for redevelopment. However due to the economic climate, construction was delayed and it was not until October 2010 that the project was revived. Oxford Properties is now co-developing the property in partnership with British Land, and in July 2011 they announced Laing O’Rourke as the Main Contractor for the works.
The new tower will feature a tapered glass façade on one side which will reveal the steel bracings, along with a ladder frame that is aimed to accentuate the vertical appearance of the tower. The base will feature a 30 metre high atrium which will be open to the public, and extend the adjacent plaza.
The structural steelwork sub-contract was awarded by Laing O’Rourke to Watson Steel Ltd. Freyssinet were selected in early 2012 to supply 162No. Tetron Disc Bearings (Pot type) which will support the floor beams on the outer columns. Freyssinet’s in-house design team worked in close liaison with Watson Steel to produce bespoke bearing designs to suit the very limited dimensional requirements with high horizontal forces. Fixing arrangements have also been tailored to comply with the restricted requirements.
Production of the bearings at Freyssinet’s factory in Telford is phased to meet the installation programme and construction is scheduled for completion in 2014.
LEADING SPECIALIST IN BRIDGE BEARING REPLACEMENT
Where the condition of your existing bearings are concerned, no one is more capable, or experienced to advise you than Freyssinet, the UK’s leading bridge bearing manufacturer and specialist in bridge bearing replacement. Freyssinet’s highly trained and experienced engineers, are available to come and complete site inspections throughout the whole of the United Kingdom and Ireland.
The services offered include identification of the bridge bearings, condition assessments, and advising on the practicalities of refurbishment, and/or bearing replacement. As part of the service, a comprehensive report is available, which would be photographically illustrated, and available in an electronic format as necessary. This allows the client to integrate our report into their own tender documentation and reports as required.
Freyssinet are the leading bearing manufacturer and experts in the fields of bridge bearing replacement, you can be assured that your new bridge bearings and bridge bearing replacement works will be of the highest quality. Freyssinet offer the full range of bearing manufacture and bearing replacements, both elastomeric and mechanical, from their UK factory. The designs are to BS 5400, and the quality control of bearing manufacture and bearing replacement exceeds the requirements of BS EN ISO 9001.
The team of leading designers at Freyssinet are able include suitable modifications into original designs of bearing manufacture, so that later bearing replacement operations can be made easier.
The replacement of bridge bearings and other operations, such as bridge expansion joint replacement, require extremely specialised jacking and propping solutions to facilitate the work. Freyssinet can offer a wide range of appropriate techniques, no matter how demanding or challenging the situation is. Freyssinet are able to supply vertical jacks to prop up structures, and also horizontal jacks, to facilitate movement of structures.
1000 tonne capacity, hydraulic jacks are available from Freyssinet with locking collars and swivel heads. To complement these, Freyssinet can use their manufacturing expertise to add to the jack heads, elastomer and PTFE sliding surfaces. These surfaces give the jack heads the ability to accommodate a limited amount of horizontal, and vertical, structural movement.
For both permanent and temporary situations, Freyssinet also supply flat jacks up to a 1000 tonne capacity, which are able to be used in gaps of 50mm or even less. For temporary solutions, where removal of the jack will be required, the inflation would be with hydraulic oil. If the bearing is to be used in a permanent situation, such as structural lifting or bearing pre-loading, a cementitious grout may be used. Alternatively, at a later date, the grout can be transfused under load if the situation requires.
Control over the entire jacking operation, can be monitored either manually or electronically, offering extremely high levels of control. The jacks can be grouped together into complex circuits, where they can be operated either in groups, or individually as required.
If the client has specified a more conventional propping system for a temporary situation, Freyssinet’s in-house designers are well placed to accommodate this, offering big advantages in terms of cost, speed and access. Propping also eliminates the need for excavation and temporary foundations.
Whether you require experts for bearing testing, or a bearing manufacturer for a bridge bearing replacement project, Freyssinet’s are the ones you should turn to.
STRUCTURAL STRENGTHENING EXPERTS
When you have a concrete structure that needs modification to prolong its lifespan, or a change of use needs to be accommodated, then strengthening is a possibility that should to be considered.
Freyssinet are in a position to offer clients a wide range of options when it comes to strengthening. Some of the potential applications for the various strengthening techniques include: increasing the floor slab load that is allowed, strengthening of the bridge deck, adding strengthening to new openings, and strengthening columns.
External post tensioning is appropriate when dealing with bridge decks in particular. Along with everything else Freyssinet have to offer is, a complete design and install post tensioning service for any of your existing structures.
No matter how big the project may be Freyssinet can meet even the most demanding post tensioning applications. If the bridge structure is a large span box girder, Freyssinet can fit additional post tensioning inside the structure itself. External post tensioning can also be used to upgrade circular storage tanks, or to make them watertight. Tendons fitted to the outside of smaller span structures, are also something offered by Freyssinet.
In existing areas that have a high stress concentration or that may be subjected to bursting forces, pre-stress may need to be introduced. Freyssinet can meet these needs with their own Freyssibar pre-stressing system. This is a comprehensive range of fully threaded, high strength bars that are complimented by extension, coupling and anchoring systems. If you have an over-stressed area of an existing structure, this solution can be an effective remedial action. Freyssibars can also be an excellent option, if you are looking to increase the load carrying capacity of your existing structure with high tensile bars.
If under strength floor slabs or beams are the problem, you may want to consider plate bonding. This is a process where Freyssinet can take appropriately sized steel plates, then bolt them or bond them, with an epoxy adhesive to a structure’s tension zone. By applying this process to the specific area, the load carrying capacity can be increased as required, up to a certain degree.
Another alternative solution offered by Freyssinet is the use of a carbon fibre product called TFC. This reinforced polymer carbon fibre product is manufactured in house by Freyssinet, and can be an outstanding option in the right circumstances. TFC can be particularly useful if the area you need to reinforce has a complex profile, or if clearance height is an issue, such as in a multi-storey car park for example. Other advantages of TFC are that it adds no extra weight to the structure, it is suitable for use in a wide range of temperatures, and it is resistant to UV, fire and shocks.
The correct type of strengthening application is dictated by the structure, its use, its design, and the amount of desired load carrying increase to be achieved. All of these factors require careful consideration, which is why Freyssinet offer a complete design and build service for its clients. Their in-house teams can assist in deciding which is the most appropriate technical and economical solution for your strengthening requirements.
BRIDGE REHABILITATION TECHNIQUES – BEARING INSPECTION, TESTING SERVICE AND BEARING REPLACEMENT
The infrastructure of modern bridges is composed of reinforced or pre-stressed concrete and steel structures. Over time, the constituent materials are affected by fatigue and general wear and tear from vehicular traffic. Wear and tear may also be aggravated by increased wheel loads and exposure to external factors such as extreme climatic conditions. Expansion/contraction and load transfer components like bridge expansion joints and bridge bearings will eventually need rehabilitation or replacement.
Expert bearing testing service
As the UK’s leading bridge bearing designer and manufacturer, Freyssinet is perfectly positioned to offer an expert bearing inspection and testing service to assess the condition of existing bearings and advise on rehabilitation. Highly qualified and experienced engineers provide on-site bearing inspections throughout the UK and Ireland and their expert bearing testing service includes the following components:
• Inspection and comment on bearing condition
• Bearing identification (including competitor’s products)
• Bearing design information and drawings from archives (where they exist)
• Advice on the practical aspects of refurbishment
• Selection of equivalent replacement bearings where necessary
• Development/budget-pricing for replacement and refurbishment proposals
• A complete photo-illustrated report
• Documents available in electronic formats for inclusion in client’s own reports/tenders
Foremost UK bearing manufacturer
As the foremost UK bearing manufacturer, Freyssinet offers a comprehensive selection of mechanical and elastomeric replacement bearings – all designed and manufactured in their UK factory to BS 5400 and exceeding the requirements of BS EN ISO 9001. Furthermore, their highly-skilled bearing design team also produce custom bearing designs to make future replacement operations easier.
Freyssinet’s testing facility offers two main test presses, namely 2000 tonne and 300 tonne. Both presses are regularly calibrated to National standards by the National Physical Laboratory.
Two calibrated horizontal strand test beds are also available, namely 1300 tonne and 500 tonne. Together with other testing equipment, the following tests can be undertaken:
• Mechanical and elastomeric bridge bearings up to 2000 tonne
• Multi strand anchorages up to 1300 tonne (BS 4447)
• Anchorage efficiency testing to BS 4447
• Force transfer testing to BS 1881
• Concrete cube crushing (100 tonne)
• Jack calibrations including stressing jacks and pot rams
One-stop bearing replacement package
A bearing replacement operation requires careful consideration of the bearing pressures, effective load transfer mechanisms, balanced gradual lifting, super-structure stability and the speed of replacement. This can require the participation of a number of different engineering specialists.
However, Freyssinet offers a complete, cost-effective one-stop package for bearing replacement – as a principal contractor or as a subcontractor. Their high quality service encompasses:
• Proven expertise in bearing design and as a bridge bearing manufacturer
• Supply and operation of jacking systems
• Expertise in specialty construction chemicals e.g. grouts and epoxies
• Hydro-demolition by an in-house team
• Innovative alternatives to conventional propping for significant time and cost benefits
Freyssinet are ISO 9001 accredited, with a long track record of quality management. When bearing replacement is undertaken, Freyssinet guarantee that the dismantling, repair, re-painting, bearing installation and re-assembly are all carried out to the same rigorously high standards insisted upon in all aspects of their business. The Highways Agency and many Local Authorities are amongst regular clients – who all trust in the proven expertise of Freyssinet for a cost-effective, durable bearing manufacture, testing and installation.
NEW REPAIR & STRENGTHENING BROCHURE
With their Repairs Division continuing to expand and adapt within the current market Freyssinet Limited have taken the opportunity to update their Repair and Strengthening Brochure and promote the wide range of products and services that they are able to offer to their clients.
FREYSSINET LTD CONTINUES TO EXCEL AT BRIDGE BEARING REPLACEMENT CONTRACTS
Freyssinet’s origins are as a specialist in bridge construction and the manufacture of bridge bearings. Their knowledge and expertise in this area remain unparalleled. An extensive track record of bridge work illustrates their capabilities to complete projects both large and small, and always to the highest standard.
During 2011 Freyssinet has sustained their success in this area, completing a number of bridge bearing replacement contracts throughout the UK.
Freyssinet Ltd were appointed by Jackson Civil Engineering to design, manufacture and install two new mechanical bridge bearings on the A14 Orwell Bridge in Ipswich, as part of the Highways Agency Area 6 Framework. Jacking and monitoring of the deck was also included within Freyssinet’s scope of works.
Overseen by Contracts Manager, Gavin Thomas, the bridge bearing replacement works were carried out during a 52hour closure of the North Deck, carrying the Eastbound A14, over the weekend of 11th-14th February 2011.
Prior to the possession, 3no jacking systems coupled with a computerised monitoring system were installed and commissioned to enable a controlled lift of the deck. The main lifting jacks were positioned on the pier top acting to the underside of the deck with a maximum uplift capacity of 3500Tonnes.
Due to the reduced capacity of the bridge box at the jacking point, a further 2 sets of jacks were installed within the bridge box to effectively brace the box and resist the forces induced via the main lifting jacks. The sets of internal jacks used were Vertical Strut Jacks with a maximum capacity of 2240Te and Diagonal Strut Jacks with a maximum capacity of 1400Te.
Once the deck had been jacked to the required height, the existing bridge bearings were removed and replaced with new. Each bearing weighed approximately 3Tonnes and had a vertical capacity of 1600Tonnes at SLS.
In March Freyssinet Ltd commenced work in Peterborough, completing bridge bearing replacement and concrete repairs for Osborne Ltd on the A1260 dual carriageway. The road, also known as the “Nene Parkway”, serves as major trunk road from the southern end to the northern end of Peterborough, circumventing the city centre. The purpose of the works was to both prolong the life of the bridge structures and enable them to continue to cope with increasing levels of traffic. The works were considered essential by Peterborough City Council; if the bridges had deteriorated further the stability and integrity of the structures would have been compromised.
A total of 7 bridge structures were included in this contract which involved the complete replacement of 12no pier crossheads on each of 4 bridges at two interchanges on the A1260 trunk road at Peterborough, and also associated concrete repair works. Concrete repairs were also carried out on 3 other nearby structures concurrent to the main works.
Each bridge was a 4 span simply supported structure, with the deck being constructed from 28 inverted ‘T‘ beams, supported at each end on 28 elastomeric pads. The elastomeric pads were due for routine replacement and Peterborough City Council decided to re-design the pier crosshead and change the support at each span end from 28no elastomeric pads to 12no elastomeric pads and 1no mechanical shear key.
This re-design would enable any future jacking of the deck to be carried out from the pier top removing the need for extensive steel temporary works.
Bespoke steel trestles were erected on either side of the pier to be strengthened. The trestles incorporated 8no 250Tonne pot jacks with mechanical bearings on top of them to enable the deck to move and rotate during the works.
The top 1.5m of the pier was removed using hydro-demolition and re-cast to the new design.
New elastomeric pads were installed on the newly formed plinths. Once the new concrete pier head had achieved the required strength, the deck was de-jacked onto its new supports and the temporary works were relocated to the next pier so that the process could be repeated.
Freyssinet Ltd was appointed by Birse Civils Ltd in April to carry out the scheduled replacement of roller bearings to 3no overbridges on the M27 motorway near Southampton.
Bespoke temporary works were designed and installed by Freyssinet Ltd. The bridge deck was then jacked to release the load from the existing bearings, the existing roller bearings were then replaced with new mechanical bearings, which were again designed and manufactured by Freyssinet Ltd’s own in-house team.
The main criteria for these works was to minimise the time period for traffic management on the M27, therefore in order to expedite the replacement process, the existing upper and lower casting plates were reused removing the curing process of new concrete & grout from the installation process. A new Highways Agency approved protective coating system was installed on these plates.
As the existing upper and lower cast in plates were found not be horizontal or parallel to each other, compound taper plates were manufactured to create horizontal and parallel bearing surfaces; these plates were installed to very tight tolerances to enable the accurate installation of the new mechanical bearings.
In June Freyssinet were selected by Southampton City Council to carry out bridge bearing replacement and concrete repairs on Itchen Bridge as part of a routine maintenance contract.
Freyssinet Ltd acted as Main Contractor and the scope of works consisted of jacking and bearing replacement, protective coating, concrete repairs and all associated works, including temporary works and traffic management.
Bespoke temporary works were designed and manufactured by Freyssinet Ltd incorporating high capacity hydraulic jacks. These were installed to support the deck during the works at the suspended span half joints and piers.
A total of 22no mechanical bearings were replaced; 12no mechanical bearings at the free end of the suspended spans, 2no at the East Abutment and 8no at prioritised piers. All of the bridge bearings were designed and manufactured by Freyssinet Ltd’s own in-house team.
The existing bearings were removed using high pressure water jetting and the new mechanical bearings were then cast into the structure prior to de-jacking the deck onto its new supports.
Whilst these critical path works were ongoing, other ‘off-line’ works such as re-wiring the internal boxes and the installation of new expansion joints were undertaken. A total of 6no expansion joints were replaced on the bridge deck during one weekend closure of the deck.
Maintenance was also carried out on all other bearings within the structure, including the application of new protective coating system.
Re-profiling works were completed on the East and West revetments to the abutments, installation of high security access doors were installed through the abutment cheek walls into the abutment chambers and the internal box lighting systems were completely rewired. Concrete repair works were also carried out as necessary by Freyssinet Ltd’s specialist operatives.
Each of these contacts was completed on programme and within budget, to the satisfaction of the contractors and the clients.
Repairs and strengthening work, and bridge bearing replacement contracts in particular continue to represent a significant proportion of Freyssinet Ltd’s turnover, demonstrating their capabilities to continuously execute this type of work to a high standard.
FREYSSINET MAKERS WORK ON PRESTIGIOUS FORTH ROAD BRIDGE
In early 2010 Freyssinet Makers, the Northern structural repair division of Freyssinet Ltd, was appointed by Balfour Beatty Civil Engineering to carry out bridge bearing replacement and associated works on one of the world’s most significant long span suspension bridges.
The Forth Road Bridge is located in Scotland, connecting Fife and the north east of Scotland with capital city Edinburgh and the south. When the bridge was opened in 1964, it was the fourth longest in the world, and the longest outside the United States, with a main span of 1006 meters between the two towers. In total, the structure is over 2.5 km long.
Since the structure was designed in the 1950s, the traffic loading on the bridge bearings has increased significantly. This can be attributed to a higher volume of traffic on UK roads, and also to an increase in the weight and number of heavy goods vehicles.
Maintenance to the Forth Road Bridge is ongoing and a large capital programme to strengthen the bridge is also continuing. In 2009 the Forth Estuary Transport Authority (FETA) embarked on a competitive tender process for the Viaduct Bridge Bearing Replacement project, estimated to total £15 million.
The contract is the biggest single contract awarded since the bridge opened. It involved the replacement of all the mechanical bridge bearings on the Forth Road Bridge’s north and south approach viaducts, which sit at either end of the bridge on each shore, connecting the A90 and M90 with the main body of the suspension bridge. The steel bearings support the bridge deck and enable it to move as required by changes in temperature. The contract also required an extensive overview of the concrete pier condition in conjunction with concrete repair works and the installation of a discreet anode CP system.
Balfour Beatty Civil Engineering was selected as the Main Contractor for the project, carrying out the works under the supervision of consulting engineers Atkins. Freyssinet Ltd was chosen to supply and install the bridge bearings, and complete associated concrete repair and cathodic protection works on the structure. The Company was able to demonstrate a successful track record with this type of work, including previous involvement with a similar project in Scotland on the Tay Bridge.
Consulting Engineers Atkins were responsible for designing the complex sequence of temporary works, permanent box girder and pier head strengthening to allow the structure to be supported on temporary jacks. In addition they supplied the detail design for the cathodic protection system.
Balfour Beatty coordinated the whole project construction sequence including supplying extensive scaffold access platforms, extension of the reinforced concrete pier head and strengthening of the steel box girder at each temporary jacking support point.
40No. permanent mechanical bearings were specially designed to BS 5400, and manufactured in Freyssinet Ltd’s factory in Telford in quality controlled conditions that exceed the requirements of BS EN ISO 9001. There were two types of bearing to be installed – fixed rocker and sliding guiding, each weighing a massive 2500kg. These replaced the existing mechanical rocker and pin roller bearings which were badly worn and corroded.
Freyssinet also designed and supplied 35No. temporary support bearings and over 100No. hydraulic jacks to meet the requirements of the temporary support and restraint works. In addition Freyssibar was supplied and stressed to assemble and fix the longitudinal restraint frames onto the structure.
Freyssinet are responsible for all the hydraulic jacking and monitoring of the bridge deck to allow removal of the existing bridge bearings. The monitoring operation comprised of a complex system of 17No. electronic sensors fixed to each pier location (19 in total). Each sensor was wired to a data-logger which captured all sensor data every 2 minutes; vertical / horizontal displacement, air temperature, pier verticality and pressures in the hydraulic support system. The system monitored the movement of the structure 5 days before the jacking operation, during the bridge bearing replacement, and for 20 days after the new bridge bearings were installed.
The bridge bearing replacement work by Freyssinet considered also the careful coordination of hydrodemolition works, steel cutting and drilling, and heavy lifting and positioning techniques to all allow the careful and safe positioning of each bearing into an extremely restricted access gap.
In addition to the bearing installation works, Freyssinet installed an extensive cathodic protection system in to areas as identified and designed by Atkins. The whole system utilised three anode systems; titanium mesh, titanium ribbon and discreet mixed metal oxide anodes.
Over 14,000m of titanium ribbon anode strip was installed into the concrete faces of the pier head cross beams and legs to form part of the CP system. Freyssinet came up with an innovative technique that utilised a chase cut into the concrete using a remote operated wall saw. This cut up to 60m per day without exposing operatives to excessive hand arm vibration or concrete dust.
Corrosion Control Services (CCSL), a sister company of Freyssinet, were involved in the procurement of specialist materials and supplied the necessary specialist site supervision / technical commissioning as required by the contract.
The Forth Road Bridge is a category ‘A’ listed structure and consent had to be granted for the works to be carried out. Selection of all repair materials and methods of placement were carefully considered in technical trials prior to the start of the works in order to meet the requirements of the consent.
The project has now been running for 12 months and is currently on schedule to be complete by the end of 2012.
Freyssinet Ltd are currently involved with the tendering process for future works on the Forth Road Bridge, and hope to continue their successful collaboration with the FETA and the other contractors working on this landmark structure.
THE FORTH ROAD BRIDGE
The Forth Road Bridge is one of the world’s most significant long span suspension bridges. With a main span of 1006 metres between the two towers, it was the fourth longest in the world and the longest outside the United States when it opened in 1964. In total, the structure is over 2.5 km long. A staggering 39,000 tonnes of steel and 125,000 cubic metres of concrete was used in its construction.
Freyssinet were appointed the sub contractors in Spring 2010 by Balfour Beatty to develop a hydraulic jacking and monitoring system to lift the bridge deck at each support structure on the northern and southern approach spans. Each support structure on the approaches (15 piers, 2 towers and 2 abutments) required to be lifted by 2mm whilst maintaining live traffic over the structure and the existing articulation of the deck. A complex system of vertical and horizontal jacks was installed in conjunction with a series of temporary bridge bearings, designed and supplied by Freyssinet, to support the structure temporarily whilst the existing bridge bearings were replaced. Each support pier required 8 temporary vertical support bearings and jack stacks weighing approx 600kg each, and 4–8 horizontal jacks to control any existing locked in forces. These support points were continually monitored to record loading information during and after the jacking operation.
A computerised monitoring system was established by Freyssinet in advance, during and post jacking operation, to record, deflections, pressures and temperatures at each support structure. When the structure was lifted, the 47 year old bridge bearings were removed using hydro demolition techniques and a system of temporary support works. The old bearings were replaced with new Freyssinet bridge bearings; fixed rocker and sliding rocker types. Freyssinet designed the new bridge bearings to very constrictive tolerances with each replacement bearing weighing approximately 2.4 tonnes.
In addition to the bearing works, Freyssinet are contracted to install an impressed current cathodic protection (CP) system, and minor concrete repairs, to areas of the supporting structures. The overall CP system utilises: discreet anodes, titanium mesh ribbon anodes and titanium mesh anode overlay. There is over 14,000 lin m of mesh ribbon to be installed between the 19 support structures alone.
Works are due to complete in Summer 2012.
Why not learn more about Freyssinet’s bridge bearing replacement services for both repair and new structure projects?