某高架曲线桥的模态实测和抗震验算

Field modal tests and seismic check of a curved overpass bridge

哈尔滨新康立交桥是高墩、独柱的小半径曲线连续梁桥。该桥位于市中心繁华地带,有特殊的重要性,需要进行详尽的抗震验算。由于地震力的大小和分布取决于结构的动力特性,而曲线桥形状不规则,受力复杂,难以用经验方法估计,因此,本文利用有限的传感器,合理布置测点,现场测试得到了结构双向水平和竖向振动的频率和振型,用以确认和校正数值模型。然后,本文应用静力法对该桥进行了初步验算,然后用反应谱法进行了多振型和多角度地震输入的线性分析,最后用时程法对该桥的抗震性能进行了进一步的验算和总结。

Xinkang Bridge is a small-radius curved overpass bridge with high piers and single columns. It is located at the busy section of the downtown area in Harbin and is of special significance to the city transportation, and thus requires a thorough seismic performance evaluation. Because the magnitude and distribution of seismic force de- pends on dynamic characteristics of the structure, while curved bridges have irregular shapes and are under compli- cated force states, it is hard to evaluate the modes empirically. So in this paper, with limited sensors and reasona- ble site selection, two orthogonal translational modes and one vertical mode were obtained by field measurements to confirm and calibrate the numerical model. Then, the seismic performance of the bridge was first examined by stat- ic method, and by response spectrum analyses with multi-mode and multi-direction earthquake inputs, and then by time history analyses.