连续梁桥模态分析与试验

Modal analysis and experiment test of continuous beam bridge

为了研究弹性基础上连续梁的振动特性,提出了连续梁桥墩的振型函数表达式。对室内连续梁桥模型进行静力试验和模态试验,并与有限元模型对比分析,研究了连续梁桥在纵桥向和横桥向的自振特性。结果表明:考虑上下部结构共同作用时,连续梁桥的低阶振动形式主要表现为桥墩的弯曲振动,试验测得的频率和由理论振型函数计算的结果误差不超过6%;说明该桥墩振型函数可以较好地应用于连续梁桥的动力计算中;这种方法可以为此类桥梁的动力和抗震分析提供参考。

The mode shape function of the feature of the continuous beam bridge sited pier was offered to study the dynamic deformation on the elastic foundation. The static experiment and modal test for a continuous beam model were carried out indoor, the results were compared with those of finite element method （FEM）, and some conclusions about the dynamic feature of continuous beam in the longitude and transverse direction were obtained accordingly. It is pointed that the whole structure＇s low vibration performs as the pier＇s flexural bending if the superstructure and substructure vibrate together. The dynamic parameters from the test have an error of 6% compared with the theoretical ones derived from modal analysis, which testifies the presented mode shape. The results indicate that： this mode shape can be well applied in analyzing the beam＇s dynamic feature; and the modal analysis method can give a good reference to the seismic analysis for the same type of bridge. 2 tabs, 11 figs, 10 refs.