M4 Boston Manor Viaduct Repairs


M4, London


National Highways

When ongoing investigations regarding the Boston Manor Viaduct revealed that there were severe cracks in the steel structure resulting from fatigue, BSS were asked to carry out repairs.


Due to the age of the viaduct, stress and fabrication flaws, we included a mixture of grinding and the manufacture of special steel plates to be bolted above and below cracks to stabilize the structure.


Technical and logistical challenges from the highly complex process for the plates were numerous; in addition to the bolt plates, filler plates were required on both sides, between the structure and the new bolt plates. These had to be milled to match the unique profile and undulations of the existing structure. We repeated this for over 30 separate locations. The existing structure had to be drilled to highly exacting tolerances. Each plate had multiple tension control bolts, which needed systematic tightening which could only be done during overnight closures to eliminate traffic loads. The need for exceptional communication and collaboration between all parties was essential to this project.  


These repairs were urgent; the viaduct was part of the Olympic Route Network, carrying coaches to and from Heathrow Airport and the Olympic Park. Closure of the M4 threatened to remove one of the key arteries for Olympic Traffic.  


BSS worked hard to meet the short deadline, and the emergency repairs were completed in time for the Olympics.  


We were shortlisted as a finalist for the Integration and Collaborative Working category in the 2013 Construction Excellence Awards for this project:  


“In addition to the pure resilience demonstrated by the entire team, key to the success was the tremendous respect the project team had for each other and their support for the goal of the project. The stabilisation of Boston Manor Viaduct shows what can be achieved when teams work together coherently, safeguarding the structure and minimising the risk of costly and disruptive closures occurring in the future.” -- Osborne Project Report. 


“A unique repair solution involving the manufacturing of bespoke specialist steel plates and their installation over the crack.” -- National Highways press release July 13th 2012. 


“I want to pass on my personal thanks to all those who worked so hard to repair the M4 bridge and get it open again in time for the Olympics. You showed real determination to get the job done in time, working through the night to do so. I was delighted to get the news very early this morning.” -- Permanent Secretary on behalf of the Prime Minister.