Rehabilitation of Old Flatts Bridge, UK

The Old Flatts Bridge in Rotherham, UK, carries the A630 Sheffield Parkway over a busy freight railway. The A630 is a key link between Rotherham, Sheffield and the M1. It is also a major arterial route into Sheffield and nearby industrial and business parks. A principal inspection of the bridge identified that the span between the abutment faces had shortened by 216 mm compared with the as-built drawings. The bearings were badly corroded and were translated well beyond their design limit, both laterally and longitudinally. The bearings were thus non-functional. The nominal movement gaps at both free and fixed ends were closed, thus ‘locking’ the structure in position. This paper describes the damage observed and the construction mechanisms that led to the failure. The paper also identifies the cause of the problem and discusses the innovative approach taken in rehabilitating the bridge. From the outset, the principal aim of the rehabilitation design was to reduce future maintenance of the structure, as the bridge is very close to a very busy motorway junction. The paper also discusses the mode of retrofitting involved in modifying the bridge’s sub- and superstructure to transform the bridge deck behaviour.