索夹对自锚悬索桥成桥状态影响分析

基于有限单元法(FEMC)比较分析了索夹对自锚悬索桥成桥状态的影响.索夹能够提高中跨主缆的成桥线形,在维持索长不变的情况下,各吊杆的成桥索力会有所增大,若使各吊杆均达到设计成桥索力值,则需增大各吊杆的无应力长度值.基于计入索夹影响的FEMC模型分别讨论了索夹长度、截面面积和惯性矩等参数对结构成桥状态的影响,并且建立了根据索夹长度比和面积比计算得到的主缆中跨跨中控制点成桥高程提升量和吊杆索力平均增量值的简化计算公式.经工程实例验证,提出的索夹模型计算结果与结构实际变形接近.

Impact Analysis of Cable Clamp on Completed State of Self anchored Suspension Bridge

The impacts of cable clamps on the completed state of a self anchored suspension bridge were analyzed based on the finite element method (FEMC). The cable clamp could raise the shape of main cable in a middle span. If the unstressed length of each boom was kept unchanged, the pulling force of each boom would increase. In the same way, if each boom was made to reach the designed force on the completed stage of a bridge, the unstressed length of each boom should be increased. Based on FEMC, the impacts of parameters, e.g. length, cross sectional area and moment of inertia on the completed state of a bridge, were studied respectively. Furthermore, the simplified formulas were established, which could calculate the elevation increment of mid position of main cable in the middle span and the average increment of each boom force by the length ratio and area ratio of cable clamp. It is verified that results from FEMC are in good agreement with the measured data.