Reopening of the Footbridge in Bratislava Exposed to Fire

Abstract Bridge failures due to fire are very rare, and they are mostly caused by traffic accidents involving a tanker truck under or on the bridge. The article deals with a fire of the high voltage electric line attached to the main girders of the approach footbridge to the Harbour Bridge over the Danube that damaged some parts of the structure. Detailed diagnostic survey confirmed that fire adversely affected the mechanical properties of the concrete in the girder’s webs and in the top reinforced concrete slab of the last span. Because their effect on the structural behaviour of the girders was very difficult to assess, the re-opening of the footbridge was conditioned by the favourable results of the load test. Due to restricted access to the cars on the footbridge, the structure was loaded with a set of water tanks that were filled with water pumped from the Danube River. Comparison of the deformations obtained on a damaged girder and a reference girder confirmed by fire caused defects when vertical displacement was 17.5% greater than in the reference girder; however, only 89 % compared with the theoretical value.