钢框架-预应力索支撑结构断索动效应

Dynamic effects on pre-stressed cable-stayed steel frame caused by sudden cable failure

为研究多层钢框架-预应力索支撑结构体系中预应力拉索在偶然荷载作用下突然断裂引起剩余结构振动响应的特征,采用瞬时加载法,借助大变形动力有限元软件ANSYS/LS-DYNA对底层一侧索支撑突然失效的一榀六层平面钢框架-预应力索支撑结构进行了动力响应的仿真分析。结果表明:剩余结构顶点侧移及与断索相邻关键构件端内力的动力系数均不大于2.0;顶点侧移、内力的最大值均发生在索完全破坏后;索的预拉力增大对断索后剩余结构的安全不利,但索直径变化对断索后的剩余结构影响不大;索的预拉力、直径变化对动力系数影响都很小。

The dynamic effects on a six-story pre-stressed cable-braced plane steel frame caused by sudden failure of a pre-stressed cable were investigated by using general finite element software ANSYS/LS-DY- NA. The instantaneously applied load method was adopted to simulate sudden cable rupture in the ground story, which can induce the dynamic response of the remaining frame structure. The results show that the dynamic coefficients of structural top lateral displacement of the remaining structure and internal forces on the end sections of the key members near the failed cable are all less than 2.0. The maximum values of structural top lateral displacement and internal forces are reached after the cable is broken completely. The larger the pre-tension in the cable, the larger the response of the remaining structure. However, the cable diameter has little influence on the response of the remaining structure. The dynamic coefficients of struc- tural top lateral displacement and internal forces are barely affected by the variations of either pre-tension or cable diameter.