在役混凝土箱梁桥顶板加劲横梁开裂分析

Cracking Analysis of Stiffening Crossgirder at Deck of Existing PC Box Girder Bridge

以某在役混凝土悬臂箱梁桥顶板加劲横梁横向开裂为背景,通过建立3D实体有限元模型和分析多种荷载工况对加劲横梁应力变化的影响,讨论了引起加劲横梁横向开裂的主要原因。结果表明,横向有效预应力不足是引起开裂的主要原因,体外预应力束张拉和车辆荷载作用加速了加劲横梁底部横向拉应力的增长,横向有效预应力下降和超载车辆作用将进一步增加顶板加劲横梁开裂的风险。

To discuss cracking reasons of stiffening crossgirder at deck, an existing PC box girder bridge was taken as the research background. A 3D solid model was built, and influences which caused by various load cases on stress distribution of stiffening crossgirder were analyzed. The results show that the main reason of crossgirder's cracking is deficient effective transverse prestress, external prestressing and vehicle loads lead to increase of transverse tension stress at the bottom of crossgirder, and overloaded vehicles and losses of effective transverse prestress would increase the cracking risk of stiffening crossgirder.