RESTORATION OF AN OVERBRIDGE ON IRAQ EXPRESSWAY

The partially completed superstructure of a 4 span concrete overbridge was struck by a dump truck on Iraq Expressway No 1 which runs between Kuwait and Jordan and Syria. The point of impact was near the top of the exterior girder just at the intersection of the girder's web with the flange at about 7 m from pier 3. The total damage consisted of the displacement of bearings from their position, non-elastic horizontal displacements and shear deformation of bearings. After checks on the foundations and compressive stress in the girders the decision was taken to repair the grout pad, to replace all the bearings to restore the bridge to its original position and to repair the broken concrete in order to restore the ultimate moment capacity of the beam. A detailed account is given of the repair work which included the raising of the superstructure by 10 mm using four Eberspacher ZE609 flat jacks which could lift 80 t under 400 bars. Bearings were replaced and jacking applied to restore the superstructure to its original position. Calculations carried out in connection with the use of the jacks are presented. (TRRL) (Author/TRRL)