系杆拱桥吊杆更换数值模拟与方案优化

Numerical Simulation and Working Procedure Optimization of Suspender Replacement of Tied Arch Bridge

以某下承式钢管混凝土系杆拱桥为工程背景,首先创建了全桥的有限元三维模型,计算了实际待更换吊杆损伤对结构性能的影响。其次,确定了吊杆更换方案和吊杆张拉步长,基于临时吊杆法,详细模拟了吊杆更换的整个过程,分析了在此过程中系杆和拱肋位置吊点的位移变化及吊杆索力变化。最后,将等步长与不等步长两类更换旧吊杆的施工方式进行了对比研究。研究结果表明:吊杆失效对失效位置处桥梁的节点位移,内力和弯矩值都有较为显著影响。设计合理的吊杆更换方案和选择适当的张拉步长能使更换过程高效稳定地进行。采用等步长与不等步长更换都能使吊杆更换平稳地进行,不等步长方案相对更为安全。

Taken a concrete-filled steel-tabular tied-arch bridge as the research object,the finite element three-dimensional model of bridge are established firstly and the influence of the actual failure of suspenders which are need replaced on the bridge performance are analyzed. Then,the procedure and stretch step size of suspender replacement are determined. The process of suspender replacement according to the temporary suspender method is simulated numerically in detail and the displacement change of the tied bar and the arch rib,as well as the cable force change of the suspender during the suspender replacement process are analyzed. Finally,two kinds of suspender replacement method respectively with equal step size and variable step size are compared. The research results show that the failure of suspenders has significant effects on the nodal displacement, internal force and bending moment of the bridge. Reasonable procedure and stretch step size of suspender replacement can ensure the efficiency and steady of suspender replacement construction. Suspender replacement can proceeded steadily with equal step size and variable step size methods,and the variable step size method is more safe.