远场地震下多跨简支梁桥搭接长度需求分析  

Demand Analysis of Support Length of Multi-span Simply Supported Beam Bridge under Far-field Earthquake

作　　者：岳伟勤 贾宏宇[1] 吴芮 游四方 陈辉煌 郑史雄[1] YUE Weiqin;JIA Hongyu;WU Rui;YOU Sifang;CHEN Huihuang;ZHENG Shixiong(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China;No.3 Engineering Co.,Ltd.,China Railway 23rd Bureau Group,Chengdu 611137,China)

机构地区：[1]西南交通大学土木工程学院,成都610031 [2]中铁二十三局集团第三工程有限公司,成都611137

出　　处：《铁道标准设计》2023年第1期144-151,共8页Railway Standard Design

基　　金：国家自然科学基金面上项目(52178169)。

摘　　要：为研究远场地震作用下简支梁桥的搭接长度需求,基于ANSYS软件建立多跨简支梁桥的三维有限元模型,分析远场地震动特征对简支梁桥搭接长度和结构弹塑性的影响;利用国内外抗震设计规范,分析简支梁桥在不同墩高、跨径下的搭接长度。分析研究表明:各国抗震规范搭接长度计算公式中,中国和日本规范搭接长度计算公式比较保守,美国东西部的抗震设防标准不同,规范计算的搭接长度差异较大,AAHSTO规范约为Caltrans规范的3倍;远场地震下的搭接长度设置满足抗震设计规范要求,当PGA为0.1g、0.15g、0.2g和0.25g时,2号桥墩墩底的弯矩和剪力最大,其塑性铰最大转角分别为0.007 39,0.007 93,0.023 2 rad和0.021 2 rad,均小于极限转角;在远场地震动不同峰值加速度作用下,墩梁相对位移最大值分别为16.6,18.7,26.2 cm和28.5 cm,占规范计算值的19%、21%、30%和32%;现有抗震规范中的搭接长度计算公式过于保守,应当结合地震动特征进行合理修正。In order to study the support length requirements of simply supported beam bridge under far-field earthquake, a three-dimensional finite element model of multi-span simply supported beam bridge is established based on ANSYS software, and the effects of far-field vibration on the support length and structural elastoplasticity of simply supported beam bridge are analyzed. Based on the seismic design codes at home and abroad, the support length of simply supported beam bridge with different pier height and span is analyzed. The analysis and research results show that among the calculation formulas of support length in seismic codes of various countries, the calculation formulas of support length in Chinese and Japanese codes are relatively conservative. The seismic fortification standards in the east and west of the United States are different, and the support length calculated in codes is quite different. AAHSTO code is about three times that of Caltrans code. The support length setting under far-field earthquake meets the requirements of seismic design code. When PGA is 0.1g, 0.15g, 0.2g and 0.25g, the bending moment and shear force at the bottom of pier 2 are the largest, and the maximum rotation angles of plastic hinges are 0.007 39 rad, 0.007 93 rad, 0.023 2 rad and 0.021 2 rad respectively, which are all less than the limit rotation angles. Under the action of different peak accelerations of far-field earthquake, the maximum relative displacements of pier and beam are 16.6, 18.7, 26.2 cm and 28.5 cm respectively, accounting for 19%, 21%, 30% and 32% of the calculated values in the code. The calculation formula of support length in the existing seismic code is too conservative and should be reasonably modified in combination with the characteristics of ground motion.

关 键 词：简支梁桥 远场地震 地震作用 塑性铰 搭接长度 弹塑性分析 动力响应分析 

分 类 号：TU311.3[建筑科学—结构工程] U442.55[建筑科学—桥梁与隧道工程]