中文摘要：

对已知标定车辆过桥产生的桥梁动应变响应进行反演计算得到相应测点的应变影响线,实现桥梁影响线动态测试。分析不同支撑边界条件下桥梁影响线的描述机理,在此基础上对动态测试的初始影响线结果进行多项式分段拟合以去除桥梁振动干扰影响,提取具有准静态特性的影响线,从数值模拟和现场试验进行验证研究。研究结果表明：所提出的拟合方法对不同类型边界条件桥梁都可从动力响应中准确提取应变影响线;各种行车工况下影响线提取结果基本一致,证实多项式分段拟合方法在去除桥梁振动干扰的同时还能较好地保证提取结果的正确性。

英文摘要：

The strain influence line of measure points on bridge structure was obtained by inversing the dynamic response of calibrated vehicle crossing the bridge structure. Based on the theory mechanism analysis of the bridge strain influence line of different boundary conditions, the idea of using a polynomial segment function to fit the initial result was explored to remove the interference caused by bridge vibration and extract the quasi-static influence line. The results of the numerical simulation and the field test indicate that the proposed piecewise polynomial fitting method can extract the bridge strain influence line under different boundary conditions. Furthermore, all extracted influence lines by fitting method are basically the same as each other despite the change of initial results with driving condition, which verifies that the piecewise polynomial fitting method has good capability of removing the influence resulting from bridge vibration and ensures the accuracy of the results.