A US$2.4 million refurbishment of Putney Bridge, which crosses the River Thames in London, UK, has been completed two weeks ahead of schedule. FM Conway was contracted by the London Borough of Wandsworth to carry out extensive work on the five-span, Grade-II listed structure which is one of south west London’s busiest crossings and was built in 1886.
Working directly with the council’s own engineers, FM Conway delivered a 13-week programme that included stripping the 210m-long bridge down to its deck, carrying out repairs to its concrete core, and laying down three coats of waterproofing to protect it from future water damage. The entire carriageway was rebuilt, the footpaths relaid with high-quality paving and the road resurfaced. The contractor also refurbished 16 ornate Victorian lanterns, which were repainted and fitted with modern, brighter LED lights.
Water had permeated the structure over the years and gathered in the 5m-square concrete cells in the superstructure. This water was damaging the structural integrity of the bridge and had to be drained by drilling into the cells from below. Inverted drilling techniques were used to access the cells - a specialist camera was used to identify the location of the water, and then additional holes were drilled to drain them. Because the Thames is tidal at Putney, parts of the bridge could only be accessed by scaffold towers brought onto the foreshore during low tide.
For the centre of the bridge, a scaffold tower had to be mounted onto a safety boat which served as the platform for drilling activities. In addition, a special cherry picker was used to provide access to the external superstructure of the bridge so that water stains could be steam-cleaned and vegetation removed.
Matt Smith, head of building and structures at FM Conway, said: “We focused on providing a quality finished product and improving on our challenging programme. The project presented a number of interesting situations including the prestigious Ride London event which was routed over the structure during the works. The project was completed two weeks ahead of programme, under budget and is a scheme the team got immense professional satisfaction from.”
