South Gloucestershire Council faced major challenges when extensive maintenance and improvements were required to the Bromley Heath Viaduct, a dual carriageway road bridge and related footpath and cycleway on the Avon Ring Road. The cycleway needed widening, but the bridge had already reached the limit of its load capacity, and this demanded use of lightweight materials. With the choice of Fiberline bridge decks of fibreglass composite, the resulting solution combined low weight with high strength and long life.

Lightweight solution

The cycleway on the heavily-trafficked bridge was no longer wide enough or safe enough to handle the 500 cyclists using it every day. At just two metres wide, and with no form of segregation from the road, the dual footpath and cycleway was no longer fit for purpose. However, widening was not easy, with challenges quickly posed by design and load capacity.

Relatively early in the design process it was found that, by using Fiberline bridge decks, the width of the path could be increased up to 3.5m without overloading the existing construction. The solution was therefore to use fibreglass bridge decks, which are known for their low weight and high strength, carried on lightweight precast concrete ribs. That way, the bridge required no further support. The bridge decks were finished with a coarse non-slip surface ideal for pedestrian and cycle paths

Innovation and good collaboration
The use of prefabricated bridge deck sections had the advantage of enabling quick and easy installation on the existing structure, thereby minimising the renovation time. The new footpath and cycleway is innovative – a hybrid bridge design - which means that different quality materials was combined. The bridges also has reduced environmental impact compared with purely concrete structures.

Fiberline has throughout the project worked closely with the entrepreneur APB Group Ltd. Innovation and Development Manager Martin Halpin tells about the project and collaboration:

“APB Group Limited are proud to be involved in innovation projects like Bromley Heath Viaduct. The team are always looking at alternative solutions to engineering challenges using Advanced Materials such as FRP where appropriate. On this project some of the major benefits of using FRP, lightweight and low maintenance, added significant value to the overall project. Collaborating with Fiberline and the other partners including main contractor Farrans and South Gloucestershire Councils Structures team ensured that the project was delivered successfully to the client’s satisfaction. Fiberline have the best and most readily available products for bridges and we look forward to the next collaboration with Fiberline to deliver cutting edge solutions to infrastructure projects”.

It is the first time that APB Group worked with bridge deck from Fiberline, but definitely not the last:

“I will promote FRP to other projects if it is the right solution. It is not about covering the world in FRP but we as an industry have to break down peoples barrier and show that it is a great and durable material” finishes Martin Halpin.