11 April 2011
11 April 2011
The HP FUTURE-Bridge project was set up to develop a new high-performance and cost-effective construction concept for bridges based on the application of carbon fibre-reinforced polymers (FRP) to effectively compete against conventional bridges made from concrete and steel.
Co-funded by the European Commission under the 6th Framework Programme of Research, this project ran from October 2006 to September 2009. Partners included Acciona, one of Spain's largest construction companies, and Huntsman.
Carbon composites are now increasingly being considered for use in bridge structures around the world. Acciona worked with Huntsman to construct a composite pedestrian bridge in Madrid, over the Manzaneres River. Because it was to be erected over a river, the bridge needed to be made from one monolithic single piece. The challenge therefore lay in designing a load bearing, jointless, single structure that was also light enough to meet the transportation, logistics and installation requirements defined for the project.
As the installation site was in the city centre, space limitations and the need to limit disruption meant the constructors were allowed a maximum of four hours to mount the bridge onsite. It was imperative that the bridge was designed to be as lightweight as possible. To achieve a weight which would assist Acciona with meeting the installation timescales while realising high levels of endurance and performance in constructing the single, jointless 44m long bridge beam, the engineers used a range of Araldite products.
The beam was produced using an injection infusion process and a wet lay-up process was used to fill and reinforce the prefabricated ribs of the bridge, bonded to the beam with an epoxy adhesive system
""We needed a thick laminates manufacturing system offering good fluidity and permeability and a bonding solution with extremely reliable adhesion,"" said Anurag Bansal, Head-Manufacturing, Infrastructures Area, Acciona R&D Centre, commenting on the choice of resin system.
From the initial fibre placement through to the demoulding and finishing processes it took a total 30 days to manufacture the bridge. The bridge was installed in less than 2 hours using a 75 tonne crane. By comparison, steel and concrete bridges typically take a minimum of 6 hours to install, using a 300 tonne crane. The significant weight saving created by the single composite beam allows smaller cranes to be used, providing an easier, faster and more economic installation process.
""By offering huge potential to produce more efficient and cost-effective structures, carbon composites could truly revolutionise the construction of long span bridges. They will also dramatically increase durability, reducing through-life costs and disruption due to reduced maintenance requirements. As early pioneers, we're proud to be at the forefront of this new era in bridge design, allowing innovative and more efficient structural forms to be conceived and constructed,"" added Stefano Primi, Head-Infrastructures Area, Acciona, R&D Centre.
Acciona is currently constructing a 200m long single beam bridge in Cuenca (Spain). The company also has plans to further explore the usage of composites in construction across Europe, with a longer term view to undertake similar projects on a global scale.
In partnership with Huntsman, Acciona won the Civil Engineering category of the JEC Innovation Awards 2011, receiving the award in recognition of the innovative use of composites in construction.
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