Are we still over-engineering bridges? That is the question being addressed by a National Highways research project.
An integral bridge on the new Wisley Interchange, where the M25 meets the A3, will be monitored by strain guagesA new integral bridge on the M25 Wisley Interchange (junction 10) improvement scheme is going to be covered in sensors to measure the actual strain and stress profiles within the bridge and surrounding soil.
The array of sensors and gauges will reveal whether the bridge could have been built with fewer materials.
According to National Highways, the research could transform future bridge construction, significantly reducing costs.
The research is specific to integral bridges, which do not have expansion joints between spans or abutments and are often used for small to medium size bridges.
Data from the Wisley Interchange bridge will be gathered every hour and analysed over a three-year period by National Highways and consulting engineer AtkinsRéalis, in tandem with researchers from Cambridge University.
National Highways has contracted AtkinsRéalis to lead the Wisley bridge trial, in collaboration with Connect Plus Services, Balfour Beatty and Laing O’Rourke.
The trial will test if current design guidance and material specifications for integral bridges could be modified, while maintaining standards, and therefore reduce embodied carbon emissions and whole life costs.
National Highways head of research Phillip Proctor said: “We are consistently looking for, and investing in, new and innovative ways to improve the way we design, build, operate and maintain our roads and our commitment to net zero is at the very heart of that search.
“This trial is important because integral bridges could offer greater durability and lower maintenance costs and provide a more sustainable alternative to the conventional design of bridge structures.”
National Highways (and predecessor bodies) has form at coming up with seemingly clever but ultimately dangerous ways to save money that later turn out to be have been ill-conceived – like widening motorways on the cheap by getting rid of hard shoulders and cutting back on safety refuges.
However, Phillip Proctor insists they won’t screw up on this one. “Safety is always our number one priority,” he said, “and we need this research to make sure any changes would still comply with the strictest safety standards.”
AtkinsRéalis director of innovation Matt Peck said: “This is the first data trial of its kind in the UK and demonstrates the value of cross-industry collaboration to support innovation and accelerate research in a real-world scenario…. it will not only provide a rich data set that can be used to support further research into how integral bridges perform over time, it will also result in significant material and cost efficiencies over the lifespan of the bridge, positively contributing towards net zero targets.”