基于微波干涉雷达的斜拉桥索力测量方法

Cable force measurement of cable-stayed bridge based on microwave interferometric radar

为提高大跨径斜拉桥索力测量的工作效率,提出了一种基于微波干涉雷达的斜拉桥索力测量方法,并将其测量结果与DaspBCF手持式索力测量仪和JMM-268接触式索力动测仪的索力测量结果进行了对比检验。该方法采用IBIS-S微波干涉雷达系统提取桥梁斜拉索动态位移信息,通过快速傅里叶变换对斜拉索位移信号进行频谱分析,获取斜拉索振动基频后基于振动频率法计算斜拉索索力。实桥试验结果表明:微波干涉雷达测量索力可同时测量多根索的动态信息,测量效率高;自下而上发射雷达波束的方法可有效规避噪声影响;该方法得到的索力与传统加速度计测得的索力相对误差在2.2%以内,测量结果可靠,并具有高效率、易操作的特点,具有很好的应用价值。

In order to improve the efficiency of cable force measurement in the long-span cable-stayed bridge, a cable force measurement method based on the microwave interferometric radar is proposed and the measurement results are compared with those of JMM-268 and DaspBCF. Firstly, the displacements of cables of the bridge were measured by the IBIS-S radar system. Then, based on the collected displacement information, fast Fourier transform(FFT) algorithm was adopted to obtain the frequency spectrum as well as the fundamental frequency of the target cables. Finally, the forces of multiple cables were identified by the oscillating frequency technique. The test results show that: the dynamic information of multiple cables can be measured by the microwave interferometric radar simultaneously with high efficiency;test method that transmits the radar wave from bottom to top can greatly avoid the influence of noise;relative errors between the cable forces calculated by data measured with radar and conventional accelerometers are less than 2.2%, which proves that the test results are reliable. The cable force measurement method in this paper is of high efficiency and easy to operate, which is worth promotion.