摘要
为探究纵筋屈服后刚度对混凝土框架在中柱失效后结构连续倒塌行为的影响,进行4个1/2缩尺的两跨梁柱子结构拟静力加载试验。其中3个试件配置具有不同二次刚度比的钢-纤维复合筋,另有1个配置普通钢筋的试件作为对比。对复合筋试件和对比试件的荷载/轴力-位移曲线、破坏模式、纵筋应变发展规律和各阶段的承载力进行分析比较。结果表明,梁机制阶段后,复合筋试件处于二次刚度和压拱复合机制阶段,与对比试件有较大不同。纵筋屈服后,复合筋试件各阶段的承载力较对比试件有明显提高。根据虚功原理,建立复合筋试件在梁机制阶段以及二次刚度和压拱复合机制阶段的承载力计算公式,且理论计算结果与试验值符合较好。基于理论计算公式揭示了纵筋的二次刚度比对试件抗连续倒塌承载力的影响规律,并根据分析结果提出复合筋的二次刚度比最大取值不宜超过0.30的建议。
In order to study the effect of the post-yield stiffness of longitudinal reinforcements on the progressive collapse behavior of concrete frame structures after the failure of a middle column,the pseudo-static loading experiments on four specimens of one-half scaled beam-column sub-assemblages with two-span beam were carried out.Three specimens were reinforced by Steel-FRP Composite Bars(SFCBs)with different secondary stiffness ratios,while the control specimen was reinforced by ordinary steel bars for comparisons.The load/axial force-displacement curves,the failure modes,the strain development of longitudinal reinforcements and the capacity at each stage of SFCB specimens were analyzed and compared with those of the control specimen.Test results show that after the flexural action stage,SFCB specimens were under the secondary stiffness plus compressive arch action(SSCAA),which is significantly different from the compressive arch action of the control specimen.After the yielding of longitudinal reinforcements,the capacity of SFCB specimens at each stage was greatly enhanced compared with that of the control specimen.Based on the principle of virtual work,calculation formulas for capacity of SFCB specimens at the stage of flexural action and at the stage of SSCAA were established,and the theoretical calculation results agreed well with the test ones.The effect of secondary stiffness ratio of longitudinal reinforcements on the enhancement of the progressive collapse resistance of specimens was revealed by the theoretical formulas.Based on the above analysis,it was suggested that the maximum value of the secondary stiffness ratio of SFCBs should not exceed 0.30.
作者
秦卫红
刘昕煜
惠卓
解鹏
黄振涛
Qin Weihong;Liu Xinyu;Hui Zhuo;Xie Peng;Huang Zhentao(Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education,Southeast University,Nanjing 211189,China;National Prestress Engineering Research Center,Southeast University,Nanjing 211189,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2022年第1期21-31,共11页
China Civil Engineering Journal
基金
国家自然科学基金(51378108,51678137)。
关键词
连续倒塌
钢-纤维复合筋
屈服后刚度
二次刚度和压拱复合机制
混凝土框架结构
二次刚度比
progressive collapse
Steel-FRP Composite Bar
post-yield stiffness
secondary stiffness plus compressive arch action
concrete frame structures
secondary stiffness ratio
作者简介
秦卫红(1968-),女,博士,副教授。主要从事预应力混凝土结构、新材料结构、结构抗连续倒塌方面的研究,E-mail:qinweihongseu@163.com;刘昕煜(1996-),男,硕士。主要从事结构抗连续倒塌方面的研究;通讯作者:惠卓(1964-),男,博士,教授。主要从事预应力混凝土结构、新材料结构、桥梁工程方面的研究;解鹏(1995-),男,硕士。主要从事结构抗连续倒塌方面的研究;黄振涛(1994-),男,硕士。主要从事结构抗连续倒塌方面的研究。
