中柱失效后预应力混凝土框架子结构动力倒塌性能试验研究  

Experimental study on dynamic collapse performance of prestressed RC frame substructures after middle column demolition

作　　者：杨涛[1,2,3] 陈万庆 郝天之[2,3,4] YANG Tao;CHEN Wanqing;HAO Tianzhi(College of Civil Engineering and Architecture,Guangxi University,Nanning 530004,China;Guangxi Key Laboratory of Disaster Prevention and Engineering Safety,Guangxi University,Nanning 530004,China;Key Laboratory of Disaster Prevention and Structural Safety of China Ministry of Education,Guangxi University,Nanning 530004,China;Guangxi Transportation Research&Consulting Co.,Ltd.,Nanning 530007,China)

机构地区：[1]广西大学土木建筑工程学院,南宁530004 [2]广西防灾减灾与工程安全重点实验室,南宁530004 [3]工程防灾与结构安全教育部重点实验室,南宁530004 [4]广西交通科学研究院有限公司,南宁530007

出　　处：《振动与冲击》2020年第20期17-23,共7页Journal of Vibration and Shock

基　　金：国家自然科学基金(51568005);中国博士后科学基金(43XB3782XB);广西重点实验室系统性研究项目(2016ZDK004)。

摘　　要：为了研究预应力钢筋混凝土(PRC)框架结构的动力倒塌性能,设计了5个1/4比例的框架子结构模型,通过快速抽柱方式对其动力倒塌性能开展了试验研究。试验结果表明:在设计荷载的动力冲击作用下,5个试件在中柱失效后的结构损伤主要表现为框架梁端开裂和结构基频的降低;预应力的施加导致失效柱处的动态竖向位移增加;当框架梁的跨度相同时,预应力可以显著改善框架梁端受拉纵筋的受力状态;非预应力试件受倒塌荷载的动力冲击作用更为显著;合理选取框架梁的跨高比和预应力的施加方式有助于控制PRC框架结构的倒塌风险。提出了针对PRC框架结构倒塌荷载动力增大系数(DIF)的计算方法,分析表明基于试验和计算所得的PRC框架试件倒塌荷载的DIF值均小于2.0,在对PRC框架结构开展静力倒塌分析时应基于失效柱的目标竖向位移确定倒塌荷载DIF的合理取值。To study the dynamic collapse performance of prestressed reinforced concrete(PRC)frame structures,five one-fourth scaled frame substructures were designed,and the dynamic collapse behavior of the specimens was investigated by the method of rapid removing a column.Experimental results show that structural damage of the five specimens caused by the impact of the design loads after the removal of a middle column was mainly manifested as the cracking of frame beam ends and the reduction of the structural fundamental frequency.The dynamic vertical displacement of the failure column increases due to the existing of prestress.When the frame beams possess the same spans,application of presress can significantly improve the stress state of the tensile longitudinal reinforcement at the frame beam ends.The dynamic impact effect of collapse load for the specimen without prestress was more significant.Adopting proper span-depth ratio of frame beams and taking suitable prestress action modes help to control the collapse risk of PRC frame structures.Finally,a method for calculating the dynamic increase factors(DIF)of collapse load for PRC frames was presented.Analysis shows that the DIF values based on the experiments and calculations were all less than 2.0.Moreover,reasonable DIF of collapse load for PRC frame structures should be adopted according to the target displacement of failure columns when collapse analysis is conducted using the static method.

关 键 词：预应力混凝土框架结构 连续倒塌 动态响应 荷载动力增大系数 

分 类 号：TU378[建筑科学—结构工程] TU375.4