基于频率法的自锚式悬索桥吊索力测试与分析

Tension measurement and analysis of hangers for self-anchored suspension bridge based on frequency method

为准确获取自锚式悬索桥体系转换中的吊索力,采用频率法对南京夹江桥进行吊索力测试.通过部分具有代表性的吊索的压力环测试读数验证了所采用的吊索参数和吊索力计算公式的精度与实用性,提出了吊索自振频率的确定方法,重点分析讨论了空间吊索面内、面外振动,吊索计算长度的选取等因素对索力测试精度的影响.测试结果表明,面内振动受桥面施工影响较大,根据拉索面外振动可以更好地确定拉索基频,从而准确测出拉索内力;同时,应充分考虑减震器和刚性锚头等因素对吊索计算长度的影响,其选取不当会造成测试结果的极大误差.

To calculate the hanger tension of a self-anchored suspension bridge under system transformation,a frequency method is used to measure the hanger tension of the Jiajiang Bridge in Nanjing.Through comparison analysis with the representative readings of pressure rings,the precision and practicality of the adopted parameters and calculation formula are validated in this paper.A determination method of the natural frequency of the hangers is put forward.Such factors as the selection of calculation length and in-plane and out-plane vibration,which have great influence on the test precision for the frequency method,are analyzed.The results demonstrate that the natural frequency can be acquired by the out-plane vibration signal,meanwhile,the effects of the damper and the rigid anchor head on the calculation length of suspenders should be fully concerned to avoid great errors of the results.