桥梁抗震分析中的激励输入模式研究

Study on Input Patterns of Excitation in Bridge Aseismatic Analysis

本文研究桥梁抗震分析中激励的输入模式。针对加速度、位移两种输入模式的特点、实现方法以及适用性进行对比分析。分析结果表明,若积分方法和步长相同,在有限元分析模型中加速度输入模式较位移输入模式容易获得更好的精度;而在模态分析模型中则得到相反的结论。为减小误差,模态模型中位移输入模式的模态力宜由等效分布荷载形式计算。实测地震加速度时程需要修正才能得到一致化的位移时程,在总结各类时域修正方法的基础上,本文提出一种频率内校正方法。

Earthquake excitation input patterns are studied.The acceleration and displacement input patterns are compared in respect of their characteristics,implementation methods and applicabilities.The results show that,with the same integral method and time step length,the acceleration input pattern is superior to the displacement input pattern in the FE model while it is opposite in modal analysis.In order to reduce errors,it is advised that the modal force of the displacement input pattern should be calculated by the equivalent distributed load pattern in modal analysis.The measured earthquake acceleration history should be corrected to obtain the consistent displacement history.On the basis of several kinds of time domain correction methods,the frequency domain correction method is proposed.