Transverse Alignment Matching Techniques for Cantilever-Assembled Wide Steel Box Girders of Wuhan Qingshan Changjiang River Highway Bridge
The main bridge of Qingshan Changjiang River Highway Bridge in Wuhan is a two-pylon cable-stayed bridge of a full-floating system.The bridge has a main span of 938 m,with stay cables fanned out in double cable planes.The superstructure consists of integral steel box girders that measure 4.5 m in depth and 48 m in full width.The steel box girder segments were cantilever-assembled using the 500 t-capacity cable cranes.Due to that the already-erected girder segments at the locations of the cable cranes and the girder segments waiting for erections were under different loading and constraint conditions,the transverse cross-sectional deformations of these girder segments revealed different trends,which imposed great challenges for alignment matching.To address these issues,cranes were deployed on both the upstream and downstream sides of the superstructure to reduce the loads of the cranes while facilitating the cantilever assembly of steel box girders in the main span.The upstream and downstream cranes were spaced at a distance of 27.7 m,as a result,the influence of the cranes on the transverse girder alignment matching was minimized.A kind of jacking devices,which comprised of pressure brackets and supporting bases,were installed at the edge webs of the girder segments at the locations of the cranes and girder segments waiting for erection to apply a pre-compressive force of 1 500 kN,assisted with several strongbacks,to complete the vertical deformation matching at the gaps via one-off loading.After construction,the transverse alignment matching accuracy of the steel box girders met the requirements.
万方数据
维普
