CFRP及EWSS复合加固震损双层高架桥框架式桥墩恢复力模型研究  

STUDY ON THE RESTORING FORCE MODEL OF SEISMIC-DAMAGED DOUBLE-DECK VIADUCT FRAME PIERS STRENGTHENED WITH CFRP AND EWSS

作　　者：许成祥[1,2] 吴永昂 胡序辉 肖良丽[1,2] XU Cheng-xiang;WU Yong-ang;HU Xu-hui;XIAO Liang-li(School of Urban Construction,Wuhan University of Science and Technology,Wuhan,Hubei 430065,China;Institute of High Performance Engineering Structure,Wuhan University of Science and Technology,Wuhan,Hubei 430065,China;Civil Engineering Co.Ltd.,China Construction Fifth Engineering Bureau,Changsha,Hu’nan 410004,China)

机构地区：[1]武汉科技大学城市建设学院,湖北武汉430065 [2]武汉科技大学高性能工程结构研究院,湖北武汉430065 [3]中建五局土木工程有限公司,湖南长沙410004

出　　处：《工程力学》2024年第5期55-67,共13页Engineering Mechanics

基　　金：国家自然科学基金项目(51478048)。

摘　　要：为研究碳纤维布(Carbon Fiber Reinforced Polymer,CFRP)及外包型钢(Externally Wrapped Steel Section,EWSS)复合加固震损双层高架桥框架式桥墩的恢复力模型,对1榀原型对比试件、1榀无预损加固试件和2榀遭受不同地震损伤加固试件进行了低周往复加载破坏试验,获取了滞回曲线并提取骨架曲线,分析其滞回特性,提出一种弹性段和强化段为双折线、下降段为指数函数且考虑初始损伤的骨架曲线模型;采用试验数据回归拟合方法,定量描述了试件滞回曲线卸载刚度的退化规律,考虑了同级加载承载力退化和定点指向特征,建立了恢复力模型。研究结果表明:复合加固试件滞回曲线捏缩现象明显,呈倒S型,各滞回环分别相交于骨架曲线上正向、负向荷载为屈服荷载0.25倍的点,峰值荷载后EWSS产生包辛格效应;所提出的骨架曲线模型对中度震损和重度震损加固试件下降段指数函数的参数k建议取值分别为3.6和3.4;所建立的骨架曲线模型和恢复力模型计算结果与试验实测结果吻合较好,可为该类结构弹塑性地震反应分析提供依据。In order to study the restoring force model of seismic-damaged double-deck viaduct frame piers strengthened with Carbon Fiber Reinforced Polymer(CFRP)and Externally Wrapped Steel Section(EWSS),the destructive tests on one prototype reference specimen and one strengthened specimen without pre-damage and two strengthened specimens with different degrees of pre-damage were carried out under low-cyclic loading.Hysteresis curves of specimens were obtained and skeleton curves of specimens were extracted,and the hysteresis characteristics were analyzed.The skeleton curve models considering the initial damage were proposed,in which the elastic segment and hardening segment are double-fold lines,and the descending segment is an exponential function line.The regression fitting method of the test data was used to quantitatively describe the degradation law of the unloading stiffness of the hysteresis curve of the specimens.Considering the strength degradation under the same level of loading and the characteristics of fixed-point orientation,the restoring force models were established.The study results show that the hysteresis curves of specimens strengthened with CFRP and EWSS are obviously pinched with the inverted S-shape.Each hysteresis loop intersects at both the positive point and the negative point of the skeleton curve,and the load at the point is 0.25 times the yield load.After the peak load,Bauschinger effect of EWSS occurs.For strengthened specimens with initially moderate and severe seismic-damage,the parameter k of exponential function of descending segment of the proposed skeleton curve model is recommended to be 3.6 and 3.4,respectively.The calculated results of the proposed skeleton curve model and the established restoring force model are in good agreement with the experimental results,which can provide a basis for the elastoplastic seismic response analysis of similar structures.

关 键 词：双层框架式桥墩 地震损伤 碳纤维布及外包型钢复合加固 滞回特性 恢复力模型 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]