考虑冻融循环作用的RC框架梁柱节点抗震性能试验及恢复力模型  

Experiment on seismic behavior and restoring force model of RC frame beam column joints considering freeze-thaw cycles

作　　者：董晋琦 郑山锁[1,2] 郑淏 尚志刚 段培亮 李亚林 DONG Jinqi;ZHENG Shansuo;ZHENG Hao;SHANG Zhigang;DUAN Peiliang;LI Yalin(School of Civil Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China;Key Lab of Structural Engineering and Earthquake Resistance,Ministry of Education,Xi'an University of Architecture and Technology,Xi'an 710055,China;School of Combat Support,Rocket Force University of Engineering,Xi'an 710025,China)

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055 [2]西安建筑科技大学结构工程与抗震教育部重点实验室,陕西西安710055 [3]火箭军工程大学作战保障学院,陕西西安710025

出　　处：《中南大学学报（自然科学版）》2022年第6期2311-2324,共14页Journal of Central South University:Science and Technology

基　　金：国家重点研发计划项目(2019YFC1509302);陕西省重点研发计划项目(2021ZDLSF06-10);西安市科技计划项目(2019113813CXSF016SF026);陕西省自然科学基础研究项目(2021JM-426)。

摘　　要：为研究冻融循环作用下RC框架梁柱节点抗震性能,首先,采用人工气候环境法对8榀RC框架梁柱节点试件进行快速冻融循环试验,进而进行拟静力试验;其次,研究冻融循环次数、轴压比及剪压比对试件破坏形态、承载力、变形及耗能能力等抗震性能的影响;最后,采用回归分析法,提出了冻融损伤RC框架梁柱节点的四折线骨架曲线模型,建立了可综合考虑加、卸载刚度退化及捏拢效应的冻融损伤RC梁柱节点恢复力模型。研究结果表明:随着冻融循环次数、轴压比和剪压比增大,试件承载力均有所降低;冻融循环次数和剪压比增大导致试件耗能能力下降,而随着轴压比提高,试件极限点的能量耗散系数呈增大趋势;试件在整个加载过程中可分为开裂、屈服、极限和破坏4个阶段,提出的四折线骨架曲线模型可较好描述各阶段受力与变形特征;通过所建恢复力模型得到的滞回曲线与试验曲线吻合较好,表明该模型能够较准确地描述冻融循环作用下RC框架梁柱节点的滞回性能。The propose of the study is to study the seismic performance of RC frame beam column joints considering freeze-thaw cycles.Firstly,8 specimens of RC frame beam column joints were tested by artificial climate environment method.Quasi-static tests were conducted on the beam column joints specimens.Secondly,the effects of the number of freeze-thaw cycles,axial compression ratio and shear compression ratio on the failure mode,bearing capacity,deformation and energy dissipation capacity of the specimens were studied.Finally,a four−line skeleton curve model of RC frame beam column joints based on freeze-thaw damage was proposed by using regression analysis method.A restoring force model of RC beam column joints based on freeze-thaw damage was established,which can comprehensively consider the loading and unloading stiffness degradation and pinch-in effect.The results show that with the increase of freeze-thaw cycles,axial compression ratio and shear compression ratio,the bearing capacity of the specimen decreases.The energy dissipation capacity of the specimen decreases with the increase of freeze-thaw cycles and shear compression ratio.With the increase of axial compression ratio,the energy dissipation coefficient at the limit point of the specimen increases.The entire loading process of the specimen is divided into four stages,including cracking stage,yield stage,limit stage and failure stage.The proposed four−fold skeleton curve model can accurately describe the stress and deformation characteristics of each stage.The hysteresis curves calculated by the restoring force model are in good agreement with the experimental curves,which shows that the model can accurately describe the hysteretic behavior of RC frame beam column joints considering freeze-thaw cycles.

关 键 词：冻融循环 RC框架梁柱节点 恢复力模型 轴压比 剪压比 拟静力试验 抗震性能 

分 类 号：TU375.4[建筑科学—结构工程]