Using plastics and glass in the construction industry could be the answer to building bridges in half the time, engineers have claimed.
The use of composite materials, such as glass or carbon fibre reinforced polymers, could dramatically reduce costs and traffic disruption.
It would also not affect the structural reliability of the completed bridges.
Composites are stiff, strong, light, corrosion-resistant materials and have been successfully used in the aerospace and automotive industries for decades.
Now researchers at Bristol University are looking at the use of advanced composite decks for traffic bridges.
Bridges using advanced composites for the deck and/or the main beams have been built in the USA, UK and Spain.
However, despite its obvious advantages, this bridge technology is not yet normal practice within modern bridge engineering.
A key issue is that very little research has been carried out examining the weathering of the composite materials and how they react to the loads bridges have to carry, especially where fatigue performance is concerned.
“Due to their low weights, high stiffness and high strength, advanced composites are leading to a new generation of lighter and more fuel-efficient aircraft such as Airbus’ A350, and also Boeing’s 787 Dreamliner which is heading towards 20% better fuel efficiency than traditional aircraft,” said Dr Wendel Sebastian, who is leading the research.
“We would like to achieve an equivalent transformation in civil engineering, with advanced composites underpinning step changes in the economics, sustainability and structural performance of road bridges.”
The Bristol team has constructed and are testing a prototype of a large-scale bridge with composite decking at the university’s structures laboratory.
The model, which is 8m long and 3.7m wide, comprises ASSET composite decking spanning across pre-tensioned concrete (PTC) main beams.
The PTC beams match the corrosion resistance of the decking and also improve stiffness.
One innovation is that only adhesive connections have been used between deck units and to connect the deck to the main beams, which simplifies and speeds up construction.
The prototype will be subjected to over 100M cycles of full-scale, code-specified fatigue wheel loading.
The large plan area of deck will investigate the effects on deck performance of different anti-skid surfaces.
Finally, the model will be loaded to failure. The results from the testing and from advanced computer models of the test specimen will underpin design guidelines for short and long-term actions of this innovative bridge form.
The project is supported by the Highways Agency, the Institution of Civil Engineers, Network Rail, Mouchel, Tarmac and Weber.