Berw Road Bridge

The Berw Road Bridge, also known as the White Bridge, is a historic Grade II listed* structure located in Pontypridd, Wales. Built in 1907 in association with L G Mouchel & Partners, pioneers of reinforced concrete construction, it was celebrated for having the longest reinforced concrete arch in Britain at the time, spanning 35 meters across the River Taff. Despite its engineering significance, the bridge faced considerable structural challenges in recent years, compounded by extreme weather events that necessitated urgent intervention to ensure its preservation.

In 1968, the bridge underwent significant modifications, including the replacement of the bridge deck and the application of gunite (a sprayed concrete coating) to reinforce the remaining elements. Further repairs to the arch ribs were carried out in 2002. The bridge serves an unclassified road with a 7.5-tonne weight restriction, and Rhondda Cynon Taf County Borough Council (RCTCBC) expressed interest in increasing the load-bearing capacity to 40 tonnes. To assess this, CRL Surveys was commissioned to conduct a structural evaluation and determine the condition of the gunite layer.

The 2020 survey revealed that 60-70% of the gunite had delaminated, significantly compromising the bridge’s structural integrity. WSP’s Structural Assessment Report from April 2020 confirmed that the bridge could only safely support its original 7.5-tonne weight limit. The potential for increasing the load capacity to 40 tonnes was ruled out without significant structural repairs.

Before work could progress, the region was struck by Storm Ciara and Storm Dennis in early 2020, causing severe flooding that extensively damaged the south pier foundation. This prompted the bridge's closure for safety reasons, and a scour survey confirmed the urgent need for repairs. These repairs were completed later that year, allowing the bridge to reopen under the existing 7.5-tonne weight limit.

After a 10-month delay caused by the storm damage, CRL was once again engaged by RCTCBC to develop a comprehensive plan to restore and preserve the Berw Road Bridge. Initially, there was discussion about demolishing the structure, but its historical importance as one of Wales' first reinforced concrete bridges made this an impractical solution. Instead, the council aimed to extend the bridge's lifespan by 50-60 years while preserving its heritage features.

CRL conducted trials to determine the most effective methods for removing the deteriorating gunite, as hydrodemolition was ruled out due to the low strength of the concrete. During the trials, spalling was identified beneath the gunite in several areas, which would need to be addressed in the final repair costs. To ensure the restoration adhered to Cadw’s (the Welsh Government's historic environment service) requirements, various float finishes, including steel and wood, were applied to trial patches, providing options for approval.

The lead engineer worked closely with CRL and the council to define the scope of works, prepare a Bill of Quantities, obtain Listed Building Consent from Cadw, and secure a Flood Risk Activity Permit (FRAP) due to the bridge’s location over the River Taff.

This early engagement and collaborative approach paid off, and in May 2022, CRL’s Bristol office was awarded the contract to undertake the restoration. The project included careful concrete repairs, gunite replacement, and the installation of galvanic anodes to prevent future corrosion. A new gunite layer was applied to match the bridge's original appearance, and the reinforcement mesh was reinstated as required by Cadw.

By July 2024, the restoration of Berw Road Bridge was successfully completed, and the structure was reopened to the public. The project not only extended the life of this historically significant bridge but also preserved its heritage, ensuring it continues to serve the community for many more years.

CRL is proud to have been a key player in restoring such a vital piece of Welsh engineering history. The use of sustainable repair techniques will help ensure the bridge's longevity and contribute to the overall safety and preservation of the UK's infrastructure.