Footbridge innovations make installation easy and ensure long life
A new footbridge providing access to an Environment Agency groundwater pumping station near Newbury in Berkshire has won the praise of local residents because of the minimal disturbance during installation. The facts that it has little visual impact and will require hardly any maintenance during its projected 25-year life are also appreciated.
The installation of the bridge in the hamlet of Bagnor was undertaken by ECS Engineering Services, which regularly works with the Environment Agency, and was mindful of protecting the quintessentially English ambience of the nearby countryside.
“This was a fantastic contract for ECS, but there was a lot to consider about the site and its surrounding area,” says Contract Manager Dave Searle. “We made sure we met with the locals and discussed options with them. The idea was to make them feel part of the project and to demonstrate that what we were doing would protect their landscape and lifestyle for years to come.”
The previous bridge had reached the end of its working life, so was in need of replacement. It spanned a small watercourse and was generally considered unobtrusive in the landscape by the locals and visitors.
“It’s the sort of feature that people can walk past every day and barely notice,” comments David. “But it is a vital part of the local fabric and the villagers were naturally concerned when they heard it was to be replaced.”
ECS Engineering Services has a well-earned reputation for delivering high quality, reliable and cost-effective engineering solutions. It specialises in bespoke design and construction of water, energy and environmental processing and management projects and, while it is perhaps best-known for major projects, each year it brings the same levels of expertise, commitment and sensitivity to many smaller jobs.
“We are recognised as leaders in the use of FRP (Fibre Reinforced Polymer) solutions for bridges, but instantly realised that would not be appropriate for Bagnor,” says Dave. “The aesthetics would have not been in keeping with the local area and installation would require the use of some fairly heavy machinery that could damage the surrounding ground, trees and ecology. Instead we settled on a solution that would appear to be a like-for-like replacement, but which would in fact be an improvement on the existing bridge design.”
An initial survey showed that the ground was extremely boggy but that the watercourse was not prone to excessive flooding. The existing timber bridge and its concrete footings were showing their age but were well designed for the duties expected of them. It was therefore decided to rebuild the footings to the same design and keep the same feel for the bridge itself.
However, ECS realised that there was an opportunity to deploy some technical innovations and improve the overall solution. Instead of timber, the bridge was constructed using KLP, a high-performance engineering material made from recycled plastic. Manufactured by Lankhorst Mouldings, KLP is a thick-walled injection moulding that can be either hollow or reinforced with a steel core.
There are many advantages to bridges made from KLP as they are maintenance free, sustainable, durable and easy to clean. KLP has an expected technical lifetime of at least 50 years and painting is no longer an issue, according to Lankhorst. Compared to wood, KLP plastic is extremely safe: the material does not splinter and has up to twice the anti-slip properties of wood, especially in wet weather or damp environments.
Dave recalls: “Installation of the bridge took only a couple of days and was largely a manual process. We did not need any lifting equipment or other heavy plant; all the component parts were light enough to be carried into position. It was all fairly quick and caused so little disruption that most of the villagers did not even know we were there.”
The bridge leads only to the pumping station and is not a public right of way, so usage levels are low, although there is the occasional need to bring grass mowers and other light machinery across it. However, the design brief also called for ECS to replace the fabricated steel security gate on the bridge, which was done at the same time as the bridge installation.
“This may have been a small job, but it was a very satisfying one. The local residents are very happy, while our use of innovative materials means they are less likely to be disturbed by maintenance crews in the future and, of course, the Environment Agency will appreciate its long life,” concludes Dave.