P.C.连续刚构桥施工过程的仿真分析

SIMULATION FOR CONSTRUCTION PROCESS OF P.C. CONTINUOUS RIGID FRAME BRIDGE

现代P.C.(预应力混凝土)连续刚构桥受力复杂,成桥应力同施工过程相关。根据其结构及受力特点,提出用实体退化单元建立P.C.连续刚构桥施工过程分析的三维模型;将预应力筋作为结构的一部分,用等效节点荷载模拟预应力的张拉效应;用三参数粘弹性模型模拟混凝土徐变效应;提出了阶段模型应力的处理方法。以一实际刚构桥为对象对该方法进行了应用研究。结果表明:P.C.连续刚构桥在恒载状态下,成桥应力和挠度与施工过程密切相关,常用的一次成桥方式获得的成桥应力和挠度与实际有较大偏差。

For a modern P.C.（prestressed concrete） continuous rigid frame bridge,its stress state is complicated,and affected by construction process.To simulate its structural behavior during construction process,degenerate solid elements were used and a three-dimensional model was set up.Taking prestressed reinforcement as a part of structure,the equivalent nodal load was obtained to calculate the effect of tensioning bars.A three-parameter viscoelasticity model was adopted to simulate the concrete creep.A processing method for internal stress of stage model was developed.A P.C.continuous rigid frame bridge was employed for the case study.The results show that the stresses and deflections of P.C.continuous rigid frame bridge under dead loads are closely related to construction process,and that the stresses and deflections obtained with commonly-used method which ignores the effect of construction process have large deviation.