Optimization Analysis of Position and the Shape of the Pre-setting Hole on Cast-in-situ Box Girder Roof

摘要

By analyzing concrete crack on the roof caused by the pre-setting hole during the construction process of the pre-stressed concrete cast-in-situ box girder bridge, this paper, which uses segment integral analysis method by ANSYS finite element program, primarily takes into account different hole position and shapes. The result shows that different position and the shape of the pre-setting hole can be seemed as decisive factors in influencing stress near the hole. It can be concluded as: the pre-setting hole should set as far as possible from pre-stressed passageway and the pre-stressed rebar first, then the shapes of hole should use circular or take corner cut polygon. Ultimately, under the premise of normal used construction, it is considerable to strive as much as possible in narrowing down the dimension of the pre-setting hole.