基于加速度多重基线校正的移动车辆下桥梁动位移间接测量方法

针对桥梁荷载试验中传统的动位移直接测量方法设备仪器安装复杂、操作难度大代价高、甚至在特殊条件下难以实现等问题，以现有相关研究成果为基础，提出一种基于实测加速度动静分离和多重基线校正策略的桥梁动位移间接测量方法。通过对加速度数据进行基线校正消除其整体偏移误差，利用快速傅里叶变换滤波消除高频噪声干扰，动静分离得到准静态和自由振动响应并分别积分后叠加。考虑动静响应特征差异提出一种新型多重基线校正方法，实现了趋势项误差的有效消除。基于所建立的位移估计方法框架和流程，通过20~40km/h多种车速下实桥现场动载试验获得的加速度和直接法动位移测试数据，对本文方法进行了试验验证。动位移估计值与直接测试值时程曲线吻合程度良好，峰值相对误差1.68%~5.29%，表明所提出的动位移估计算法具有较高的精度和工程适用性。

Displacement Indirect Measurement Method of Bridge under Moving Vehicle Based on Multiple Baseline Correction of Measured Acceleration Response

The traditional direct measurement method of dynamic displacement in bridge load test has the problems of complicated equipment installation, difficult operation and high cost. Based on the existing research results, an indirect measurement method of dynamic displacement of bridges was proposed using the dynamic-static separation of measured acceleration and multiple baseline correction strategies. After the baseline of measured acceleration data was corrected to eliminate overall deviation, the filter with FFT was used to remove high frequency noise. The dynamic-static separation was applied to achieve quasi-static and free vibration response before integration and final superposition. A new multiple baseline correction method was proposed considering the difference of dynamic and static response characteristics to achieve the effective elimination of trend term errors. The framework and process of the proposed method was established and then verified based on a real bridge in-situ dynamic load test. The dynamic displacements of bridge under vehicle with 20-40km/h speeds were estimated based on the proposed method by measured accelerations. The curves of estimated and directly measured displacements were compared. The results show good agreement and the relative peak errors are in the range of 1.68%~5.29%. It is concluded that the proposed method has a satisfied accuracy and can be applied in engineering practice.