摘要
双层高架桥框架式桥墩受力复杂,震害严重,在实际桥梁工程中的应用越来越多。为研究震损双层高架桥框架式桥墩经碳纤维布(CFRP)及外包钢复合加固后的地震易损性,以原型、直接加固、中损加固、重损加固4榀双层框架式桥墩为研究对象,采用双参数地震损伤模型计算损伤指数以折减材料性能来模拟地震损伤,利用OpenSees开放平台建立精细化的非线性有限元模型。基于桥墩的低周往复荷载分析,对比模拟与试验的滞回曲线和骨架曲线,验证模型的可行性。在此基础上,以规范反应谱为目标从美国太平洋地震研究中心(PEER)数据库选择20条实际地震动记录作为输入,对桥墩模型进行增量动力分析。以峰值加速度作为地震动强度参数,以位移延性比作为工程需求参数,通过定义4种损伤极限状态进行地震易损性分析,以峰值加速度中位值和增强系数定量评估桥墩复合加固的效果。研究结果表明:震损加固后的桥墩比加固前更不容易受到地震的损坏,对于轻微、中等、严重、倒塌4种损伤状态,中损加固后桥墩的增强系数分别为90.5%,106.3%,119.6%,127.2%;重损加固后桥墩的增强系数分别为85.1%,100.4%,113.2%,120.6%。因此,在重度地震损伤范围内,CFRP和外包钢复合加固震损双层高架桥框架式桥墩是有效的。
Double-deck viaducts’ frame piers, which are increasingly used in bridge engineering, have complex forces and serious earthquake damage. In order to study the seismic fragility of seismic-damaged double-deck viaducts’ frame piers strengthened with CFRP and enveloped steel, the four-layer prototype, direct reinforcement, medium damage reinforcement, and heavy damage reinforcement double-deck frame piers were the research objects. The two-parameter seismic damage model was used to calculate the damage index to reduce material properties to simulate seismic damage. A precise nonlinear finite element model was built on the OpenSees platform. Based on the low cyclic loading analysis of the bridge piers, the comparison of the hysteresis curve and the skeleton curve of the simulation and test verifies the feasibility of the model. On this basis, with the standard’s design response spectrum as the target, 20 actual ground motion records were selected from the ground motion database of Pacific Earthquake Engineering Research(PEER) as input to perform incremental dynamic analysis on the bridge piers model. The peak acceleration was used as the ground motion intensity measure, and the displacement ductility ratio was used as the engineering demand parameter. The seismic fragility analysis was carried out by defining four damage limit states, and the effect of composite reinforcement was quantitatively evaluated with the median value of PGA and reinforcement factors. The results are drawn as follows. The reinforced piers after seismic damage are less susceptible to seismic damage than before reinforcement. For the four damage states of minor, moderate, severe, and collapse, the reinforcement factors of the reinforced piers after moderate damage are 90.5%, 106.3%, 119.6%, and 127.2%, respectively. The reinforcement factors of the piers after heavy damage reinforcement are 85.1%, 100.4%, 113.2%, and 120.6%,respectively. Therefore, in the range of severe seismic damage, seismic-damaged double-deck frame piers strengthened with CFRP and enveloped steel are effective.
作者
许成祥
吴永昂
罗恒
胡序辉
XU Chengxiang;WU Yongang;LUO Heng;HU Xuhui(School of Urban Construction,Wuhan University of Science and Technology,Wuhan 430065,China)
出处
《铁道科学与工程学报》
EI
CAS
CSCD
北大核心
2022年第3期733-742,共10页
Journal of Railway Science and Engineering
基金
国家自然科学基金资助项目(51478048)。
关键词
桥梁工程
双层框架式桥墩
震损加固
碳纤维布
外包钢
地震易损性
bridge engineering
double-deck frame piers
seismic damage reinforcement
CFRP
encased steel
seismic vulnerability
