Jon Shave of Parsons Brinckerhoff says the UK should be more confident in the use of fibre reinforced polymer structures to fully realise the benefits.
The use of fibre reinforced polymer (FRP) materials comprising fibres in a polymer resin matrix has many potential benefits for civil engineering applications. In particular, the materials do not corrode, they don’t need to be painted, and they are lightweight but very strong. It is convenient to prefabricate entire lightweight structures that may be rapidly installed without large cranes. These properties can result in structures with minimal maintenance requirements and benefits in sustainability, safety, and cost over their design life.
There have been some very successful examples of bridges constructed entirely from FRP, using a variety of moulding and pultrusion technologies. Many of these followed the 2003 Parsons Brinckerhoff report for Network Rail on the use of FRP in the rail environment, which highlighted footbridge construction as a promising application for the materials. But although the 10 or so bridge applications such as the PB-designed St Austell Footbridge and the Leri River Footbridge have been a success, widespread adoption of FRP bridges has not yet permeated the mainstream.
One reason could be connected to the design codes for FRP structures. At the moment there isn’t a Eurocode for these structures as there is for other materials. Design work is generally performed by specialists who already understand the unusual properties of the materials and how to assure safety, serviceability, durability, and robustness. But work is afoot to improve this situation. There is a European working group which is developing a technical report that could be the basis of a future Eurocode for FRP.
In the UK, the Network Group for Composites in Construction (NGCC) has also set up a group to develop design guidance for FRP bridges which is nearing publication. It has been drafted by representatives from design specialists, clients, materials suppliers, and fabricators.
Another development is the Duracomp research project carried out by a consortium of organisations led by Warwick University and funded by Engineering and Physical Sciences Research Council (EPSRC). This project seeks to investigate and quantify the durability benefits of FRP materials thus reducing uncertainty and improving economy.
We have the knowledge, skills, and experience in the UK for FRP structures to flourish. Organisations such as the NGCC are working to bring the industry together and promote composites in construction. FRP structure costs have reduced and are already competitive with conventional structures in many cases. But by considering larger volumes, the costs can reduce further. If we can follow the example of countries like the Netherlands and be more confident in the use of FRP structures then our clients and society could be benefitting in terms of sustainability, safety, and cost.
Jon Shave is UK head of specialist civil engineering consultancy services at Parsons Brinckerhoff, as well as a steering group member, NGCC and industrial partner of the Duramcomp project.