摘要
为减少传统防屈曲支撑(BRB)的十字形支撑内芯在焊接后所产生的残余弯曲变形,提出一种新型全角钢式防屈曲支撑(ABRB)。该支撑的内芯由4个等边角钢通过屈服段无焊接技术组合而成,约束构件则由两个等边角钢沿纵向焊接组合而成。对4个ABRB试件进行拟静力滞回性能试验,重点考察支撑边界条件,支撑端部转动约束构造、内芯外伸段构造以及加力长度等因素对其滞回性能的影响。试验前首先对试件内芯的初始弯曲进行测量,结果表明,绝大多数试件内芯屈服段的相对初始弯曲均有效控制在1/1000以内。拟静力试验结果表明,当支撑端部边界条件为固接时,ABRB的延性及耗能发展最为充分;当支撑两端为铰接且支撑端部无转动约束时则较容易发生内芯外伸段的局部压弯破坏,且当加力长度增加时,局部压弯破坏则越早发生,但该破坏模式可通过在铰接ABRB两端设置转动约束构件的构造予以避免。对试件的抗震性能分析表明,构造合理的ABRB表现出较好的延性以及十分稳定的累积滞回耗能特性,因此ABRB可作为有效的耗能减震装置应用于工程结构中。最后提出进一步改进的建议以及有待深入研究的问题,为此类支撑性能的进一步完善奠定基础。
To minimize the residual welding deformation in the steel core of cruciform cross-section of conventional buckling-restrained braces（BRBs）,a novel type of all-steel BRB,called Angle BRB（ABRB）,has been developed.The steel core of ABRB consists of four angle steels of equal sides to form a non-welding cruciform yielding cross-section,and the outer restraint is composed of two angle steels of equal sides welded longitudinally to form a square hollow cross-section.Uniaxial quasi-static cyclic tests for four ABRB specimens were carried out to investigate the hysteretic behavior,in which the effects of boundary condition,construction of rotation restraint at the brace end,construction at the core projection,loading length,etc.are considered.The relative initial geometric imperfection in the yielding segment of the steel core specimens was measured before the tests,which shows that such imperfection can be well controlled within the limit of 1/1000.The test results indicate that the ABRB specimens with rigid connection exhibit better hysteretic performance than other specimens.The local compression-flexure failure mode is inclined to occur at the core projection for the ABRB specimens with pin connections and without rotation restraint at the brace end.The local compression-flexure failure occurs earlier when the loading length increases,which can be safely prevented by setting rotation restraint at the brace end.The seismic behavior of the ABRB specimens are analyzed and it is revealed that the ABRB specimens with rational constructions exhibit plump and stable hysteretic performance before failure,indicating good ductility and satisfactory cumulative hysteretic energy dissipation capacity,which shows that ABRB can serve as an effective passive energy dissipation device for structures.
出处
《土木工程学报》
EI
CSCD
北大核心
2011年第4期60-70,共11页
China Civil Engineering Journal
基金
国家重点基础研究发展计划(973计划)(2007CB714204)
国家科技支撑计划(2006BAJ03B06-01
2006BAJ06B03-03)
关键词
防屈曲支撑
角钢
滞回性能
压弯破坏
累积塑性变形
buckling-restrained brace
angle steel
hysteretic behavior
compression-flexure failure
cumulative inelastic axial deformation
