连续刚构桥施工过程中腹板斜裂缝成因分析及试验研究

摘要

In order to explore the reason that cracks are discovered along the bellows direction on the girder construction process of pre-stressed concrete continuous rigid frame bridge, the stress of the web are tested before and after the pre-stressed tensioning, and the space finite element model is established by using ANSYS software for analyzing the reinforcement ratio of the web, the change of longitudinal pre-stressing of the roof, the change of vertical bending longitudinal pre-stressing of the web, the change of the vertical pre-stressing and the thickness of the web.The results show that reinforcement ratio of the web and longitudinal pre-stressing of the roof are not the sensitive factors for the inclined cracks in webs of the process of construction.The vertical bending longitudinal pre-stressing of the web, vertical pre-stress and thickness of the web are found to be the sensitive factors for generating the cracks.In order to avoid the occurrence of diagonal cracks in the web of box girder, the ideal sequence about pre-stressed tensioning is: first, tensioning the longitudinal pre-stressing of the top plate, and then tensioning the vertical pre-stressing of the web, tensioning vertical bending longitudinal pre-stressing of the web at the end.%为了查找预应力混凝土连续刚构桥施工过程中箱梁腹板沿波纹管方向产生斜裂缝的原因,对预应力张拉前后进行了腹板应力测试,并利用ANSYS软件建立空间有限元模型,对腹板配筋率、顶板纵向预应力变化、腹板竖弯纵向预应力变化、腹板竖向预应力变化和腹板厚度变化等影响腹板裂缝出现的因素进行了分析.结果表明,腹板配筋率和顶板纵向预应力不是箱梁施工过程中腹板斜裂缝的敏感因素,腹板竖弯纵向预应力、腹板竖向预应力和腹板厚度对腹板斜裂缝的产生比较敏感.避免箱梁腹板斜裂缝发生的理想预应力张拉顺序是:先张拉顶板纵向预应力,然后张拉腹板竖向预应力,最后张拉腹板竖弯纵向预应力.