预应力混凝土箱梁腹板主应力分析

Principal Stress Analysis for Web of PC Bridge with Box Section

预应力混凝土箱型截面桥梁结构是我国桥梁工程中最常用桥型结构形式之一。已建成的此类桥梁中有不少出现了腹板开裂现象,裂缝成因与主拉应力计算影响的因素有关。结合公路桥梁结构设计系统GQJS按照JTG D62-2004新桥规的改版工作,讨论变高度梁弯矩轴力修正、钢筋换算截面修正以及竖向预应力等因素对箱梁腹板主应力计算的影响,并结合实例进行分析,对比新、旧规范在斜截面抗裂性能验算方面的不同要求。

PC Bridge with box section is one of the most popular structure types in the bridge construction in China. Some cracks had appeared on the webs of these box girder bridges. It is relative with the calculation of principal tension stress. Combining with the work of bridge structure design system （Chinese name abbr. GQJS） modified according to the new Chinese Bridge Code （JTG D62-2004）, the influences of calculating factors of principal stress of web of box girder bridges are discussed, such as internal forces modification of variable height girders, conversion section of reinforcement bars and vertical prestressing force. And a practical case is analyzed to compare different requirements for crack resistance under the new Codes and old Codes.