连续梁桥横向抗震挡块简化分析方法研究

摘要

Under earthquakes,the reasonable design of aseismic retainers has a good effect on the upper structure of a bridge.The guidelines for aseismic design of highway bridges only ask to install retainers in construction measures,but do not indicate its aspecific design method.In order to simplify the design process of retainers and improve the calculation efficiency,here the simplified method of continuous girder bridge's calculation model was studied and the dynamic features of the simplified model were compared with those of the FE model to verify the former's rationality.The vibration modal shapes participating in the simplified analysis were studied.The results showed that for regular bridges,only considering transverse translational modal shapes can meet engineering precision requirements;Compared with the calculation methods in codes of United States and Japan,the simplified method falls somewhere between them,so the simplified method's reliability is verified;due to considering the influence of structural dynamic characteristics,the seismic forces of retainers decrease with increase in pier height,so the calculation results of the simplified method are more reasonable.%地震作用下,经过合理设计的挡块对桥梁上部结构具有很好的限位作用.《公路桥梁抗震设计细则》仅在构造措施中要求设置挡块,但未明确其具体设计方法.为简化挡块设计过程,提高计算效率,对连续梁桥计算模型的简化方法进行研究,并通过简化模型的动力特性与有限元模型对比,验证了其简化的合理性;对简化分析中需考虑的参与振型进行了研究,结果表明,规则桥梁仅需考虑横向平动振型就可基本满足工程精度要求;相较于美国规范和日本规范的计算方法,简化方法基本介于两者之间说明了计算结果的可靠性,且由于考虑了结构自身动力特性的影响,计算的挡块地震力随着墩高的增大而减小,计算结果更为合理.