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
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.
To download the new brochure please click below
Freyssinet makes the Shortlist for 2012 Specialists Awards
Freyssinet are pleased to announce that they have been short listed in the ‘Concrete’ category of the 2012 Specialists Awards.
The Awards look to commend the work of specialist contractors in the construction industry, recognising the valuable role that they play in projects large and small.
Freyssinet was asked to reflect on the company’s performance between November 2010 and 2011, providing examples of notable successfully completed contracts, demonstrating client satisfaction, and describing how the company has grown and developed within this time.
Freyssinet was keen to highlight the unrivalled diverse offering and range of technical skills that they provide to their clients, along with their commitment to further developing the company through the acquisition of an in-house hydrodemolition team and the launch of their site-based apprenticeship scheme. In particular Freyssinet have experienced growth within their repair activities, demonstrating innovation and versatility.
Making the shortlist is a huge achievement and Freyssinet look forward to attending the Awards ceremony in London on March 20th 2012.
Bulgari Hotel wins Concrete Society Award
The 43rd annual presentation of The Concrete Society’s Awards for Excellence in Concrete took place on 10th November 2011 in London.
The Sustainability Award went to the Bulgari Hotel and Residences (formerly the Knightsbridge Palace Hotel) in London, where Freyssinet Limited undertook the design, supply and installation of a post-tensioned floor slab system.
Appointed by Byrne Bros in early 2010, the installation works were carried out by Freyssinet between August and December 2010.
The building consists of high-quality residences overlooking Hyde Park, a luxury hotel, restaurant, ballroom and a swimming pool.
The use of post-tensioned floor slabs in the structure contributed to meeting the client’s aspirations for a ‘green’ building, utilising approximately 25% less concrete and 65% less steel reinforcement compared to a traditionally reinforced structure.
Freyssinet Join Alliance to Revolutionise Offshore Wind
VINCI Construction UK Ltd., and sister VINCI company – Freyssinet International & Cie, have created a joint venture to revolutionise the delivery of offshore wind farms. Developed with support from the Carbon Trust by GBF®, a consortium of Gifford, BMT Nigel Gee, and a specialist arm of Freyssinet – the alliance’s low cost, low risk and low impact approach includes a radical solution for deploying foundations without the need for costly specialist vessels or heavy lifting at sea. The team’s approach also includes a manufacturing process for assembling entire wind-turbine structures onshore before deploying them at sea.
The team’s product comprises a Gravity Based Foundation to be slip formed on land. The tower and turbine will be installed in the construction yard in a continuation of the base production line – economies of scale and a slick methodology will ensure the complete assemblies are produced economically. The completed units will be deployed and installed on the seabed with the assistance of a Transportation & Installation Barge (TIB). The TIB is a low cost, low maintenance dumb barge, built specifically for this process.
Based on UK Government commitments, a six-fold increase in output from wind will be required by 2020. The VINCI Construction UK – Freyssinet JV will construct and deploy the GBF® concept which is set to change the economics of offshore wind farms suitable for gravity bases The JV believes that its methods will enable deployment of turbines in rougher seas and deeper waters than conventional alternatives. A further key advantage is that a completely different supply chain is called upon compared to the better known monopile or jacket solutions.
VINCI Construction UK and Freyssinet International will jointly develop the innovative solution. Close partnerships and collaboration will be critical to the success of the project, and the JV will be working with developers, turbine manufacturers and others, including other companies from the wider VINCI Group to ensure the right arrangements and skills are in place.
There are also considerable environmental benefits to the proposed offshore scheme. The foundations themselves can be made from recycled materials, and the environmental impact throughout the lifecycle of the structures will be minimal. The foundations are designed such as that they can be completely removed at the end of their useful life and hence will have minimal long term impact on the environment once they’ve been decommissioned. While providing local employment opportunities, the projects will also, of course, help the UK to meet its renewable energy targets and deliver sustainable energy in the years ahead.