Concrete beams key to A418 road bridge completion

The A418 road bridge near Aylesbury has reopened after a week-long closure, marking the completion of its realignment over the HS2 route, with 21 U-shaped precast concrete beams used to form the three spans of the new bridge.

The new 103m-long structure is a critical part of the HS2 development, which is transforming transport links between London and the West Midlands. It sits over a cutting that will carry high-speed rail services, and along with the nearby A41 bridge, is one of two major concrete bridges recently opened in the area.

Ben Sebastian-Green, senior project manager at HS2, said: “The A41 and A418 are two of the most important roads into Aylesbury, so it’s great to have both bridges open to the public. The role of concrete in this project has been essential, from the precast beams to the in-situ casting of the bridge deck and wingwalls. I’d like to thank everyone involved in the supply chain for their hard work, and the local community for their patience during the recent closures.”

The construction of the A418 bridge involved the installation of 21 precast concrete beams, each one carefully placed to form the three spans of the bridge. The deck and wingwalls were cast in-situ, using a mix designed to meet the project's specific requirements. Concrete was also key in the realignment of the road, with more than 10km of utilities, including power cables, telecoms cables, and water mains, installed alongside the road.

The bridge's realignment spans 1.1km and includes additional infrastructure improvements, such as new drainage systems and wider footpaths and cycleways, all constructed with concrete. These upgrades aim to improve safety and accessibility for the community.

Ignacio Chicharro, project director at EKFB – the joint venture behind the bridge construction – explained: “The realignment of the A418 and the new overbridge wouldn’t have been possible without the careful planning and execution of the concrete works. From the precast beams to the cast-in-place concrete elements, the project required close coordination. We’re pleased to reopen the road and appreciate the patience of the local residents during the closures.”

Although much of the work was completed without affecting traffic, several temporary road closures were required for utility diversions and to safely connect the new bridge with the existing road. Pedestrian access was maintained throughout, and a replacement bus service was provided for residents during the closures.

The A418 bridge is just one part of HS2’s ongoing development, which will feature more than 500 bridges, viaducts, and other structures, many of which rely heavily on concrete for their construction. The HS2 project aims to improve transport efficiency between London and the West Midlands while providing long-term environmental benefits, including reducing congestion on the West Coast Main Line and enabling greater use of rail for freight.