汽车撞击桥墩瞬态撞击力的等效静力计算

摘要

随着公路、铁路、城市立交桥的大量建设，跨线桥数量剧增，桥墩被汽车撞击的可能性大大增加。建立卡车撞击桥墩精细有限元分析模型，采用LS-DYNA碰撞分析软件计算分析了Ford卡车以不同速度撞击桥墩的撞击力特性。采用全局平均法、局部平均法、等效位移法、简化脉冲荷载法4种计算汽车撞击力等效静力方法，计算了撞击过程的等效静力值，并与美国《AASHTO》规范、中国《铁路桥涵设计基本规范》和《公路桥涵设计通用规范》中给出的汽车等效静力限值进行了比较，指出了各种计算方法的适应范围和精确度，可供工程设计参考。%Due to quick development of elevated overpass bridges of highways,railways and urban overpass nowadays,the probability of vehicle colliding with piers increases sharply.An analysis model for a truck-pier system was set up using the finite element software ANSYS LS_DYNA to analyze the impact force characteristics of the truck at different speeds.Here,four calculation methods for equivalent static force of truck-pier collision force were presented including the global average method,the local average method,the equivalent displacement method,and the simplified pulse load method.Using these methods,the equivalent static forces were calculated,and the results were compared with the allowances given in AASHTO-LRFD,Chinese Railway Code and Chinese Highway Code.Based on comparisons,the adaptive scope and the accuracy of the four methods were pointed out,a reference was provided for engineering design.