摘要
通过钢支撑-混凝土框架振动台试验研究了钢支撑失稳或其他构件损伤后引起的扭转突然增大问题,即非弹性扭转问题,结果表明钢支撑受压失稳或失效是导致此类结构出现非弹性扭转的重要原因。基于试验结果,分析了钢支撑失稳或失效导致结构非弹性扭转突增的机理;同时建立了设有偶然偏心的有限元模型算例并进行非线性分析,验证了在增加构件数量的条件下该类结构仍存在非弹性扭转突增问题,表明即使是对称结构,在普通钢支撑发生受压失稳及其反向受拉过程中,也会产生非弹性扭转及其突然增大现象。试验和案例分析均表明类似的现象,即在相同加载及偏心条件下纯混凝土框架非弹性扭转虽然存在,但其突然增大值比钢支撑框架结构要小;设置防屈曲支撑抗扭效果显著,优于设置钢支撑的混凝土框架和纯混凝土框架。建议工程设计中设置防屈曲支撑,可有效减控混凝土框架非弹性扭转危害;通过设置质量偏心,对钢支撑-混凝土框架结构进行强震下非弹性扭转响应分析,并在设计上对其最大值加以限制。
With shaking table tests of steel braced concrete frames,an issue of suddenly increasing torsion duo to steel brace buckling or other elements damage,i. e. inelastic torsion,is studied. Test results indicate that steel brace buckling or failure would be the main cause of the inelastic torsion in this kind of buildings. Based on the test results,the mechanism of the suddenly increasing inelastic torsion is studied,some FEM models of calculation examples with preseting occasional eccentricity are established,and nonlinear analysis are conducted. With the analytical models,the sudden increasing torsion issue is verified still existed while the number of elements in symmetric structure is increased but the brace number remains unchanged. It is cleared that even if it is a symmetrical structure,both routings of brace buckling or its re-straightening will induce the inelastic torsion and its sudden increase. Although there are inelastic torsion in pure concrete frames,but it perform a smaller torsional amplitude increment than steel braced one under same loading and eccentricity conditions,and not only tests but also analytical models reveal the similar phenomenon. With installed buckling-restrained braces（BRB） in concrete frames, it has been proved significantly effective to resist nonlinear torsion,superior to steel braced concrete frame or pure concrete frame. There are suggestions to structural engineers as follows： installing BRB is suggested to effectively minimize and control the inelastic torsion of concrete frames,it is recommended that a non-linear FEM analysis with preset occasional floor mass eccentricity to get inelastic torsion under strong earthquakes,and the maximum torsional response should be limited to a reasonable value in seismic design stage.
作者
高向宇
李建勤
刘超
李杨龙
GAO Xiangyu;LI Jianqin;LIU Chao;LI Yanglong(Key Laboratory of Urban Security and Disaster Engineering of China Ministry of Education, Beijing University of Technology, Beijing 100124, China;State Power Economic Research Institute, State Grid, Beijing 102209, China;Beijing Electric Power Engineering Company, Beijing 100070, China)
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2018年第2期44-53,共10页
Journal of Building Structures
基金
国家自然科学基金项目(51378038)
北京市自然科学基金重点项目(8141001)
关键词
钢支撑-混凝土框架
非弹性扭转
防屈曲支撑
振动台试验
抗扭设计
steel-braced concrete frame
inelastic torsion
buckling-restrained brace
shaking table test
anti-tosionaldesign
