PC连续刚构桥梁底合理曲线线形研究

Research on Reasonable Curve Shape of Girder Bottom of PC Continuous Rigid Frame Bridges

针对PC连续刚构桥梁底长束的张拉导致合龙段箱梁底板和腹板开裂问题,以黑崖沟2号桥为背景工程,探讨了采用不同次数梁底曲线对箱梁局部应力状态的影响。在此基础上,揭示了箱梁易于开裂的危险部位,分析了导致开裂的主要原因,提出PC连续刚构桥梁底曲线次数不低于1.6次的建议。同时,结合实际工程,通过对三种防裂设计方案的理论研究与实桥测试结果的比对发现,采用跨中设置实体隔板的设计方案,可有效地解决合龙段箱梁底板下缘和腹板内侧的开裂问题。

When tensioning the bottom prestressing tendons of PC continuous rigid frame to cause the bottom and web of closure segment to crack. Taking Heiyagou 2 Bridge project background, the influence of box girder local stress caused by different power of beam bottom in this paper beam bottom . By analyzing the likely crack parts and revealing the reasons, it is suggested bridge, it is likely as the engineering curves are studied that the power of curve of PC continuous rigid frame bridge should not be less than 1.6. Comparison between the re- suhs from theoretical analysis and from actual test on the bridge shows that solid diaphragm design can effectively solve the cracking problem at bottom slab and webs inside edges.