18 December 2012
The Hebron oil field is located offshore Newfoundland and Labrador in the Jeanne d’Arc Basin 350 kilometres southeast of St. John’s. The field was first discovered in 1980, and is estimated to contain 660-1055 million barrels of recoverable crude oil. The Hebron field will be developed using a stand-alone concrete gravity based structure (GBS). The GBS will consist of a reinforced and post-tensioned concrete structure designed to withstand sea ice, icebergs and meteorological and oceanographic conditions. It will be designed to store approximately 1.2 million barrels of crude oil. The GBS will be 120m tall, 130m diameter and stand in 93m of water. It will support an integrated topsides deck that includes living quarters and facilities to perform drilling and production.
The GBS was towed out to the Deep Water Site (1km away from the Dry Dock Site) on 22nd July 2014. This was a key accomplishment of an important project milestone.The GBS was towed out of the dry dock and anchored at the Deep Water Site thanks to 9 mooring brackets, each of them being fixed to the GBS structure by means of 8 units of 19C15 tendons installed by Freyssinet. The GBS will remain at this mooring station until completion of the concrete works and readiness of the top side platform for connection in 2016.
The busiest construction phase of the project has now started, the concrete structure will be slip-formed over 44m in height in 37 days, i.e. an average production speed of 1.2 m of slipformed walls every 24 hours, during which the 1,400 staff and labour involved on the floating GBS will install the 15,000 tons of rebars and 50,000 m³ of concrete. During this phase, the Freyssinet team will be supervising the installation of the 85,000 m of corrugated ducts (95mm & 105mm).
The Freyssinet crew will then undertake the installation of 600 tons of horizontal post tensioning out of the 2,000 tons remaining until completion of the project in 2016. Over 400 vertical “U” shaped tendons will be threaded and stressed in the autumn 2015.
In addition, in June 2014, the project has reached 10,000,000 working men hours with no Lost Time Injury. This is a massive accomplishment for such a project employing over 3,500 staff and labour.
FREYSSINET SUPPLY CE MARKED BEARINGS FOR THE NEW WALTON BRIDGE
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 REMAINS AT THE FOREFRONT IN DESIGN AND CONSTRUCTION OF POST-TENSIONED FLOOR SLABS
Post-tensioning technology
Freyssinet is an acknowledged leader in specialized civil engineering and introduced post-tensioned concrete building floor slabs to the UK in the early 1980’s. Since that time we have championed this technology and contributed to its acceptance as a standard technology and consequent exponential increase in utilisation in the last decade. We offer a full service from conception through detailed design and site installation utilising our in-house design team and experienced site managers and operatives.
The environmental credentials of post-tensioned construction are one of the major selling points when the client’s team are trying to determine the construction material. Typically, post-tensioned slabs save about 25% of the slab depth and hence 25% of the concrete volume, when compared to the Reinforced Concrete (RC) equivalent. The steel content (reinforcement and post-tensioned combined) is often reduced by 65%.
Other advantages of post-tensioned construction include:
• Increasing spans and load carrying capacity;
• Reducing slab thickness;
• Eliminating beam downstands;
• Reducing self weight, quantities of materials and loads on foundations;
• Considerably reducing and simplifying passive reinforcement;
• Reducing the number of expansion joints and columns;
• Better punching shear characteristics;
• Outstanding behaviour in seismic zones;
• Increased cracking resistance;
• Increased waterproofing due to concrete compression;
• Reduced excavation in basements;
• Deflection control;
• Removal of the formwork within 3 days;
• Environmental benefits, less concrete, less steel, fewer lorry journeys.
2012 Freyssinet projects
• Wade Deacon
Wade Deacon School is a 4 storey extension of an existing school in Widnes, Cheshire constructed by Heyrod Ltd. The Ground flood is ground bearing and was cast in reinforced concrete, and Freyssinet were appointed to construct the 3 suspended levels above in post-tensioned concrete floors.
The post-tensioned levels were built in a 16 week schedule starting in early January 2012 till the end of April 2012. The concrete frame consists of a 230mm deep PT slab with a 4B13 system of bonded tendons. Each floor consisted of 6 separate pours with an average area of 550m2 and a total post-tensioned area of 9,750m2.
• Hoe Street
Hoe Street is a partial residential and partial commercial structure consisting of blocks A and B and is located in Walthamstow, North London. Block A contains both residential and hotel floor space, the latter owned by Novotel while Block B is purely residential. All suspended slabs were constructed by Freyssinet in post-tensioned concrete in a 40 week work program for Principal Contractor Vinci Construction. Work started in December 2011 and is planned to finish by the end of December 2012.
Block A is a 13 level block of which the first 8 levels are split between residential and commercial floor space while levels 9-13 are purely commercial. The total area of this block is 3,400m2 of residential floor space with 4B13 bonded tendons and 3,600m2 of hotel floor space with 4B15 bonded tendons. Slab thicknesses vary between 225mm and 375mm at transfer levels.
Block B is an 8 level block with a slab thickness of 225mm and also includes a 300mm podium slab on Level 1 and has a total area of 4,000m2. The system used is a 4B13 bonded strand system throughout the block.
• Great Marlborough Street
Great Marlborough Street is a 34 storey student accommodation block situated near the centre of Manchester. The frame contractor was Heyrod and the job was completed in a 48 week program from February 2011 through to January 2012. Due to the small spans in the layout, the frame was constructed mostly by 200mm deep post-tensioned slabs, and partially by 250mm deep as well as 3 transfer slabs with a thickness of 450mm by use of a 4B13 system and the total area of slab is 13,600m2.
• Cambridge Mosaic
Cambridge Mosaic is also known as The Marquee and consists of 7 levels of post-tensioned slabs and another 4 levels of RC slab and is currently the tallest building in Cambridge. The frame contractor is Getjar Ltd and the frame is being constructed on a 21 week program, due to finish in the next few weeks.
Except for the basement which is reinforced concrete, the remaining levels from Ground Floor to Level 6 are post-tensioned by use of both 4B13 and 4B15 systems and a total slab area of 15,000m2. The basement serves as a parking space and storage while the Ground floor is the commercial level consisting of restaurants and retail shops while the remaining levels are luxury apartments.
FREYSSINET AND GALGLASS – A SUCCESSFUL PARTNERSHIP CONTINUES
Galglass are design and build specialists for concrete and steel storage tanks. As the market leading specialist contractor in the design and construction of cylindrical post-tensioned (PT) in-situ reinforced concrete sludge digester tanks in the UK, Galglass first appointed Freyssinet by as their post tensioning partner on the design and construction of 3No. 18m dia. x 15m high tanks at Ringsend sewage treatment works in Dublin in 2000/01. Freyssinet were initially selected by Galglass as their partner because of their unrivalled reputation, expertise and experience in the post tensioning sector, with the relationship also bringing commercial and quality advantages.
Since then, the partnership has grown from strength-to-strength. With the latest round of water industry investment programmes coinciding with increased emphasis on renewable energy, which can be generated using methane gas (a natural by-product of the sludge digestion process), Galglass has seen the demand for digester tanks increase dramatically since 2009.
To date Freyssinet have supplied and installed post tensioning systems at four Galglass project sites in the UK and Ireland:
• Ringsend WwTW Tank 4, Dublin, 2009
• Afan Sludge Digester Tank, Port Talbot, 2010
• Five Fords WwTW, Wrexham, 2011
• Howdon Digester Tanks, Newcastle, 2011
Historically, tanks of this type were designed and constructed traditionally with very thick and heavily reinforced concrete wall sections. Even then, tanks designed and constructed in this way would frequently suffer wall cracking and leakage, leading to a reduced operational life and client dissatisfaction; in addition, construction of such tanks was costly and slow, and the carbon footprint of structures of this type was very large. The key benefit of the innovative Galglass Post Tensioning approach to digester design is that it ensures that the tank walls are maintained in permanent horizontal compression under all load cases and for the whole design life (typically 40 – 60 years) of the structure, thereby guaranteeing leak-free construction. The use of post tensioning also allows much more economical wall thicknesses and reinforcement quantities, so that costs and build times are significantly reduced and the associated carbon footprint is dramatically lowered.
Freyssinet’s in-house design team consists of suitably qualified experienced engineers and technical personnel with many years of experience in post-tensioned tank design and construction.
They are responsible for:
1. Deciding on the suitable post-tensioning system to suit to the range of stress resultants provided by Galglass analysis
2. Estimation of post tensioning losses for the selected post tensioning system
3. Calculation of required number of tendons
4. Providing effective tendon layouts that can easily be adopted on site
5. Providing technical assistance during the design development and construction
All in all, the partnership with Freyssinet presents Galglass with a “win/win” situation in promoting its market-leading PT digester product – Galglass Engineering Director Lindsay Powell says:
“The credibility that the Freyssinet name and reputation brings to our highly successful PT digester system is clearly recognised by ourselves and our clients. The quality and high performance levels of the finished product speak for themselves, and it is reassuring to know that we can rely on the skills, experience and technical/site services support offered by Freyssinet for projects of this type. The highly successful track record of the partnership and the corresponding high levels of customer satisfaction are a credit to both Galglass and Freyssinet, and with a number of high-profile digester projects currently ongoing and more in the pipeline, it is a partnership which we feel will continue grow and develop in the future to the continued benefit of both parties”.
Freyssinet and Galglass are currently in negotiations for further works at Blackburn Meadows WwTW, Sheffield, Woodhouse Mill WwTW, Sheffield and Bellozanne WwTW, Jersey.
FREYSSINET CONTINUES TO EXCEL IN THE DESIGN AND INSTALLATION OF POST-TENSIONED FLOOR SLABS
Freyssinet is an acknowledged leader in specialized civil engineering and introduced post-tensioned concrete building floor slabs to the UK in the early 1980’s. Since that time we have championed this technology and contributed to its acceptance as a standard technology and consequent exponential increase in utilisation in the last decade.
We offer a full service from conception through detailed design and site installation utilising our in-house design team and experienced site managers and operatives.
Post-tensioning provides a great many advantages, including:
• Increasing spans and load carrying capacity;
• Reducing slab thickness;
• Eliminating beam downstands;
• Reducing self weight, quantities of materials and loads on foundations;
• Considerably reducing and simplifying passive reinforcement;
• Reducing the number of expansion joints and columns;
• Better punching shear characteristics;
• Outstanding behaviour in seismic zones;
• Increased cracking resistance;
• Increased waterproofing due to concrete compression;
• Reduced excavation in basements;
• Deflection control;
• Removal of the formwork within 3 days;
• Environmental benefits, less concrete, less steel, fewer lorry journeys.
The environmental credentials of post-tensioned construction are one of the major selling points when the client’s team are trying to determine the construction material. Typically, post-tensioned slabs save about 25% of the slab depth and hence 25% of the concrete volume, when compared to the Reinforced Concrete (RC) equivalent. The steel content (reinforcement and post-tensioned combined) is often reduced by 65%.
Vinci Construction recently appointed Freyssinet to design post-tensioned floor slabs for UPP at Byron House student accommodation in Nottingham. Freyssinet were involved with Vinci’s bid from tender stage, which contributed to them winning the contract. Frame contractor David Ashley Construction then contracted Freyssinet to complete installation works.
Freyssinet also assisted Vinci, and frame contractor Getjar, with their bid to construct the mixed use Mosaic development in Cambridge. Freyssinet’s early involvement and assistance with value engineering helped to give Vinci an edge. Construction of the superstructure will commence in July 2012.
A further post-tensioned floor slab contract recently awarded to Freyssinet is the Eldon Theatre at Portsmouth University. Again, Freyssinet’s input at tender stage assisted the Main Contractor Morgan Sindall in securing the project. Morgan Sindall then recommended Freyssinet to frame contractor Stephenson Construction and superstructure construction is due to start in mid June 2012.
Freyssinet are close to completing post-tensioned floor slab works on site at St Peters School in Stoke on Trent for frame contractor Metropolitan Developer.
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.
FREYSSINET PROMOTES POST-TENSIONED CONCRETE TECHNOLOGY IN THE CONSTRUCTION OF SCHOOLS AND COLLEGES
Freyssinet introduced post-tensioned concrete building floor slabs to the UK in the early 1980’s. Since that time they have championed post-tensioning technology and contributed to its acceptance as a standard system of construction.
Offering a full service package, their in-house design team can support clients from conception through detailed design and site installation utilising experienced site managers and operatives. Freyssinet sets high and specified performance criteria positioned above the usual industry standards.
Last year Freyssinet successfully completed a number of post-tensioned slab contracts for the construction of schools and colleges throughout the UK. These included:
• The Learning Centre, Ebbw Vale Campus, Wales
• Bourneville College, Birmingham
• The Big Build, Rutland
• Orminston Academy, Birmingham
• Sir Robert Woodard Academy, Lancing
Freyssinet have recently been awarded further post-tensioned floor slab contracts for Wade Deacon High School in Widnes and the Learning Resource Centre at Stafford College. Freyssinet first got involved with the Wade Deacon project over a year before it was finally let, working with VINCI Construction to give cost advice on a concrete alternative to the then conforming steel framed structure with precast concrete flooring units. The post-tensioned alternative saved significantly on the build cost and the flat soffits assisted the architectural planning and services layout.
The structure consists of a spine block running the full length of the 106m long historic façade. Springing from the spine are three teaching wings, each comprising an atrium bounded by classrooms on either side. The three storey structure has 9,750m2 of suspended PT slabs, all being 230mm deep, each floor will be concreted in six pours.
The post-tensioning system selected by Freyssinet’s in-house design team is the 4B13 bonded system. At level 1, two 1000x350mm deep PT beams have been used to span up to 13.7m to allow a pair of columns to be omitted thus creating a feature access way. And on the roof level the same sized PT beams cantilever 3.3m thus avoiding having to run columns down through teaching space below.
Post-tensioned concrete is an ideal choice for academic building construction. It reduces the depth of the structural members meaning the floor to floor height is reduced. Post-tensioned concrete also has excellent deflection control due to the inbuilt parabolic profiles of the tendons, which directly counter deflection effects.
There is plenty of experience within Freyssinet of building post-tensioned concrete academic buildings. The majority of these have been designed and detailed by our in-house team of qualified and experienced engineers and technicians.
Post-tensioning provides a great many advantages, including:
• Increasing spans and load carrying capacity;
• Reducing slab thickness;
• Eliminating beam downstands;
• Reducing self weight, quantities of materials and loads on foundations;
• Considerably reducing and simplifying passive reinforcement;
• Reducing the number of expansion joints and columns;
• Better punching shear characteristics;
• Outstanding behaviour in seismic zones;
• Increased cracking resistance;
• Increased waterproofing due to concrete compression;
• Reduced excavation in basements;
• Deflection control;
• Removal of the formwork within 3 days;
• Environmental benefits, less concrete, less steel, fewer lorry journeys.
The environmental credentials of post-tensioned construction are one of the major selling points when the client’s team are trying to determine the construction material. Typically, post-tensioned slabs save about 25% of the slab depth and hence 25% of the concrete volume, when compared to the Reinforced Concrete (RC) equivalent. The steel content (reinforcement and post-tensioned combined) is often reduced by 65%.
In addition to academic buildings, post-tensioning also suits a wide variety of projects, such as:
• Offices
• Retail developments
• Underground car parks and multi-storey car parks
• Hospitals
• Business centres
• Industrial buildings
• Sports buildings
• Residential towers
FREYSSINET IS AWARDED FURTHER CONTRACTS UNDER HA FRAMEWORK
Freyssinet Limited has recently been awarded three further contracts within the Highways Agency Area 9 &10, Construction Management Framework.
The works, which commenced on site in March 2012, include:
• A40 Bridstow Bridge – Concrete bridge repair, cathodic protection, bearing refurbishment and joints
• M50 Queenhill Viaduct Phase 3 – Concrete repair, cathodic protection and drainage works
• M50 Pendock Sledge and Queens Arms – Concrete repair, cathodic protection and joints
The CMF is a collaborative approach to maintaining £75billion worth of assets for HA in these areas over the next 4 years. It consists of a number of different contractors from different specialist areas who work together to deliver network improvement and maintenance schemes on the all purpose trunk road and motorways in Highways Agency Area 9 and 10, which covers much of the West Midlands and North West.
Freyssinet Ltd, and their sister company Corrosion Control Services Ltd (CCSL), both form part of the CMF, having been selected for their skills and experience in concrete structure repairs and concrete corrosion prevention techniques.
To date Freyssinet Ltd and CCSL have completed six other contracts under the CMF agreement:
• AC5/AC7 Gravelly Hill – Concrete repair, bridge bearing replacement works and cathodic protection
• Oldbury Viaduct – Cathodic protection
• M6 Rayhall Viaduct – Concrete repair and cathodic protection
• M50 Kempley Road Bridge – Concrete bridge repair
• M5 Northway Decks – Concrete repair and deck strengthening
• Bromford Viaduct – Concrete repair and cathodic protection
The CMF contract is different to the traditional sub contract relationship. It is based on partnering, encouraging open working relationships and providing opportunity to develop and share innovative practices.
FREYSSINET LIMITED WORK WITH VINCI CONSTRUCTION UK TO WIN CONTRACT
Streatham Hub is a multi-million pound regeneration project by Lambeth Council in partnership with Tesco. The Hub site covers the old ice rink and leisure centre between Streatham High Road and Streatham Station.
The development includes the construction of a replacement sports centre and ice rink, the Tesco store, a bus interchange close to the station, a public square and new homes. The Hub is expected to create around 600 new jobs for Streatham when it opens in 2013.
The project involves an undercroft car park, two storeys of retail store and a transfer structure above that which supports the residential blocks. To one side is the bus interchange, energy centre and service yard all above more undercroft parking. To the other side is a link block and the leisure centre, including the new ice rink and swimming pools.
The total post-tensioned slab area on the project is expected to be 21,250m2.
During the tender stage Freyssinet supported VINCI with value engineering options which assisted in winning VINCI the contract. The majority of these options are now being taken forward into construction as follows:
• The Tescos Store was a 600mm deep cobiax (voided) slab spanning 16×7.5m car park grid. This has been replaced by 2400x550mm deep PT beams and 250mm PT slabs, thus saving 50mm of dig across the 75x75m store footprint.
• The Bus Hub and Service Yard support HA loading and comprised 1600x900mm deep RC beams with 450mm RC slabs. The adopted PT solution has 425mm fl at slabs with 3m2x550mm OA depth drop heads at columns.
• The Link Block contains a 400mm deep PT transfer slab with 1200sq x 550 OA deep column caps at level 1. This carries 5 levels of metsec residential block above. Previously, in RC, this slab was a 600mm deep solid slab.
• The ground level of the Link Block has been post-tensioned too (previously 600mm deep RC cobiax, now 350mm PT flat slab). By post-tensioning isolated beams, previous head room clashes with vehicle ramps below have been solved.
• The Ice Rink slab was designed as PT by Halcrow Yolles from the outset because of the extremely fine deflection control required. It typically consists of 1000x1400mm deep beams and 300mm deep slabs.
Freyssinet Limited was appointed as the specialist PT contractor for this contract in August 2011 and design works have commenced. Construction work will commence in April 2012 and the PT slabs are due to be completed by January 2013.
Streatham Hub, along with Hoe Street and Wade Deacon School are examples of contracts where Freyssinet is supporting VINCI Construction bid teams at tender stage. This synergy between companies is giving them an edge through proposals to use post-tensioning and innovative engineering.
FREYSSINET LTD’S COLLABORATION WITH THE HIGHWAYS AGENCY CONTINUES
Freyssinet Ltd, and their sister company Corrosion Control Services Limited (CCSL), form part of the Highways Agency Area 9 &10, Construction Management Framework.
The CMF is a collaborative approach to maintaining £75billion worth of assets for HA in these areas over the next 4 years. It consists of a number of different contractors from different specialist areas who work together to deliver network improvement and maintenance schemes on the all purpose trunk road and motorways in Highways Agency Area 9 and 10, which covers much of the West Midlands and North West.
Following a comprehensive application process, Freyssinet were selected as the specialist contractor for Concrete repairs and Cathodic Protection (in a joint venture with CCSL).
The Companies were assessed on their experience and track record of work, as well as in terms of health and safety, quality and environmental policies and procedures.
The CMF began in January 2010, and the contract will run for 4 years with a possible 2 year extension.
To date Freyssinet Ltd and CCSL have completed 4 contracts under the CMF agreement:
• AC5/AC7 Gravelly Hill – concrete repair, bridge bearing replacement works and cathodic protection
• R153 Oldbury – cathodic protection
• M50 Kempley Road Bridge – concrete bridge repair
• M5 Northway Decks – concrete repair
Works are due to commence on site at R159 in August 2011.
The CMF contract is different to the traditional sub contract relationship. It is based on partnering, encouraging open working relationships and providing opportunity to develop and share innovative practices.