高阶振型对高墩桥梁抗震性能的影响及其识别  

Effect of higher modal shapes on aseismic performance of a bridge with high piers and its identification

作　　者：卢皓[1] 管仲国[1] 李建中[1] 

机构地区：[1]同济大学桥梁工程系,上海200092

出　　处：《振动与冲击》2012年第17期81-85,98,共6页Journal of Vibration and Shock

基　　金：国家科技支撑计划(2009BAG15B01);国家自然科学基金项目(51008222);西部交通建设科技项目(200731882233)

摘　　要：针对高60 m、90 m的典型高墩桥梁,运用增量动力分析方法(IDA)和基于基阶振型的非线性静力推导方法(MPA)计算高墩屈服位移、极限位移、位移延性以及临界状态的墩身曲率分布,通过两种方法计算结果的对比分析,评价不同地震波激励下,高阶振型对桥墩延性能力的影响。描述不同地震作用下曲率沿墩高的分布,指出高墩桥梁在强震作用下,除墩底塑性铰外,还会在墩身中上部形成第二个塑性铰区域,并绘制能力谱和需求谱识别高墩在不同临界状态下各高阶振型进入塑性的程度,证实墩身出现塑性铰主要是由于第二阶振形的贡献。For bridges with 60m,90m pier height, yield displacements, ultimate one, displacement ductility and curvature distribution of the critical state were determined with the incremental dynamic analysis （IDA） and pushover method considering the fundamental mode （MPA）. After analyzing the results from IDA and MPA, the effect of higher modal shapes on pier ductility was evaluated under different earthquakes. Curvature distribution along piers under different earthquakes were described to reveal that under the action of strong earthquake plastic hinges are developed at the middle and the upper parts of pier except the base of pier. Capacity diagrams and demand diagrams were developed to identify the plastic level of higher mode respectively in different critical states, they were used to verify that the occurrence of plastic hinge at middle and upper parts of pier is attributed to the contribution of the second modal shape.

关 键 词：高墩 位移延性能力 高阶振型 IDA PUSHOVER方法 塑性铰 

分 类 号：P315.9[天文地球—地震学]