Nature Proves No Inhibitor To Concrete Bridge Repair

摘要

Bats, periods of prolonged persistent rainfall and fluctuating river levels were just some of the obstacles faced during the refurbishment of Clifton Bridge in York - a process that used traditional and innovative repair techniques.rnClifton Bridge is a six-span structure, each span comprising 22 prestressed, precast, Dow Mac beams spanning 16.5m and supported on in-situ reinforced concrete piers, abutments and wingwalls. The bridge was opened in 1964 and carries the two-lane principal road (Water End) over the River Ouse, a navigable waterway, and provides a clearance of 7.3m above mean summer level of the river.rnFollowing an inspection of the bridge, the city engineers, supported by a specialist concrete testing survey (including subsurface half-cell testing and rate of corrosion calculations), decided that the optimum time to commission refurbishment works to the bridge had been reached. The works would address the problems of chloride contamination, spalling concrete and the tired anti-carbonation coating, with the aim of prolonging the effective life of the structure. Following a competitive tendering process Topbond was appointed to undertake the works, which were carried out by its northern division, based in North Lincolnshire.