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11.
Effect of non‐moment braced frame seismic deformations on buckling‐restrained brace end connection behavior: Theoretical analysis and subassemblage tests 
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下载免费PDF全文 In‐plane buckling‐restrained brace (BRB) end rotation induced by frame action is a commonly observed phenomenon in buckling‐restrained braced frames (BRBFs). However, its effect on BRB end connection behavior has not yet been clear. In this study, four BRB end deformation modes for quick determination of end rotational demand are proposed for non‐moment BRBF considering different BRB arrangements, installing story of BRBs, and boundary condition of corner gussets connected with column base. Key factors affecting BRB end rotation and flexural moments are examined theoretically by parametric analysis. Subassemblage tests of seven BRB specimens under horizontal cyclic loading were conducted by adopting two loading frames to impose the expected BRB end deformations. It shows that BRB end rotation subjected BRB ends to significant flexural moments, leading to premature yielding of BRB ends or even tendency of end zone buckling. The deformation modes, the flexural rigidity of BRB ends, and the initial geometric imperfections of BRBs were found to have significant influence on BRB end connection behavior. The triggering moment induced by BRB end rotation was the main contributor to end flexural moment. However, the moment amplification effect induced by flexure of BRB end zones became prominent especially for small flexural rigidity of BRB ends. Implications and future research needs for design of BRB end connections are provided finally based on the theoretical and experimental results. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
Buckling‐restrained braces (BRBs) are widely used as ductile seismic‐resistant and energy‐dissipating structural members in seismic regions. Although BRBs are expected to exhibit stable hysteresis under cyclic axial loading, one of the key limit states is global flexural buckling, which can produce an undesirable response. Many prior studies have indicated the possibility of global buckling of a BRB before its core yields owing to connection failure. In this paper, BRB stability concepts are presented, including their bending‐moment transfer capacity at restrainer ends for various connection stiffness values with initial out‐of‐plane drifts, and a unified simple equation set for ensuring BRB stability is proposed. Moreover, a series of cyclic loading tests with initial out‐of‐plane drifts are conducted, and the results are compared with those of the proposed equations. © 2013 The Authors. Earthquake Engineering & Structural Dynamics published by John Wiley & Sons Ltd. 相似文献
13.
设置防屈曲支撑的钢管混凝土框架是一种新型钢管混凝土减震结构。采用有限元软件Opensees对设置防屈曲支撑的单层单跨钢管混凝土减震框架进行数值模拟,研究了框架梁柱线刚度比、防屈曲支撑初始刚度以及钢管混凝土柱轴压比等设计参数对该减震结构抗震性能的影响。研究结果表明：1数值模拟和试验结果吻合较好,验证了有限元模型的正确性;2梁柱线刚度比在0.1~0.3之间变化时,钢管混凝土减震框架的抗震性能较好;3BRB耗能支撑的初始刚度K1在40~80kN/mm变化时,减震框架的耗能减震效应较明显;4在合理的钢管混凝土柱轴压比范围内,当轴压比较大时,在钢管混凝土框架中设置防屈曲支撑能明显地提高结构的耗能能力和改善结构的强度退化现象。 相似文献
14.
使用偏心支撑减小不规则高层建筑的扭转振动效应 总被引：7，自引：0，他引：7
郭仕群 《地震工程与工程振动》2005,25(3):76-80
文章对比分析了一个不规则高层钢筋混凝土框-剪结构和在原结构基础上增设偏心支撑后的新结构的抗震性能,比较了它们的自振特性以及层间位移等地震作用效应。针对不规则高层建筑在地震作用下不可避免的扭转振动问题,提出在结构中适当地增设偏心支撑来减小结构的扭转振动效应及其它结构地震反应这种简单可行、经济适用的方法。 相似文献
15.
宿迁市建设大厦消能减震设计 总被引：2，自引：0，他引：2
宿迁市建设大厦,21层,框架-抗震墙结构,按Ⅷ度(0．3g)进行抗震设防;由于建筑部分楼层层间位移超过《规范》要求,因此在部分楼层增设消能支撑,通过提高结构的附加阻尼比来降低结构的位移反应。整体结构的非线性时程分析结果表明,在框架-抗震墙结构中增设消能支撑,可以较为经济地控制结构薄弱层的位移,提高结构的抗震安全储备。本文可为高烈度区类似工程的设计提供借鉴。 相似文献
16.
针对单层异形柱框架,通过高温数值分析,考察了支撑设置和受火位置对结构高温变形及内力的影响。研究结果表明：对于单层多跨异形柱框架,当只有一端有支撑跨时,会在一定程度上增大另一端的边节点水平位移和边柱侧向变形,对结构整体抗火不利;当左、右两端均有支撑跨时,非支撑跨在火灾作用下的梁轴力比很大,升温后期可能因梁跨中竖向位移急剧增大而发生破坏。基于上述研究结果,给出了4类单层带支撑异形柱框架火灾行为的初步判定方法。 相似文献
17.
Yi‐Jer Yu Keh‐Chyuan Tsai Chao‐Hsien Li Yuan‐Tao Weng Ching‐Yi Tsai 《地震工程与结构动力学》2013,42(9):1301-1320
The seismic performance tests of a full‐scale five‐story passively controlled steel building were conducted on the E‐Defense shaking table in Japan in March 2009. Before the tests, a blind prediction contest was held to allow researchers and practitioners from all over the world to construct analytical models and predict the dynamic responses of the steel frame specimen equipped with buckling‐restrained braces (BRBs) or viscous dampers (VDs). This paper presents the details of two refined prediction models made and results obtained before the tests. When the proposed analytical modeling techniques are adopted as in the two refined prediction models, the overall prediction accuracy is about 90%. Sensitivity studies conducted after the tests are also presented in this paper. The effects of varying each modeling feature on the response simulation accuracy have been investigated. The analytical results suggest that considering concrete full‐composite actions for beam members could improve prediction accuracy by about 20% against using the simplified bare steel beam model. Adopting refined BRB stiffness computed from incorporating finite‐element gusset stiffness only improves the overall prediction accuracy by 0.9%. Considering the BRB dynamic loading test results for analytical BRB strength reduces the error by 1.9%. For the VD frame, incorporating the brace and VD stiffness could improve the overall prediction accuracy by about 15%. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
18.
Evaluation of the response modification coefficient and collapse potential of special concentrically braced frames 总被引：1，自引：0，他引：1
Special concentrically braced frames (SCBFs) are commonly used for seismic design of buildings. Their large elastic stiffness and strength efficiently sustains the seismic demands during smaller, more frequent earthquakes. During large, infrequent earthquakes, SCBFs exhibit highly nonlinear behavior due to brace buckling and yielding and the inelastic behavior induced by secondary deformation of the framing system. These response modes reduce the system demands relative to an elastic system without supplemental damping using a response modification coefficient, commonly termed the R factor. More recently, procedures put forth in FEMAP695 have been made to quantify the R factor through a formalized procedure that accounts for collapse potential. The primary objective of the research in this paper was to evaluate the approach for SCBFs. An improved model for SCBFs that permits simulation of brace fracture was used to conduct response history analyses. A series of three‐story, nine‐story and 20‐story SCBFs were designed and evaluated. Initially, the FEMAP695 method was conducted to estimate collapse and the corresponding R factor. An alternate procedure for scaling the multiple acceleration records to the seismic design hazard was also evaluated. The results show significant variation between the two methods. Of the three variations of buildings studied, the largest vulnerability was identified for the three‐story building. To achieve a consistent margin of safety against collapse, a significantly lower R factor is required for the low‐rise SCBFs (three‐story), whereas the mid‐rise and high‐rise SCBFs (nine‐story and 20‐story) may continue to use the current value of 6, as provided in ASCE‐07. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
19.
设计了12组41种二重钢管防屈曲耗能支撑试件,应用有限元软件ABAQUS对其进行了有限元分析,研究了径厚比、约束比、长细比和边界条件对支撑性能的影响.分析结果表明:二重钢管防屈曲耗能支撑的径厚比取值不大于24、约束比的取值不小于3时,支撑的滞回曲线饱满、稳定;当支撑的长细比增加时,可以通过提高约束比来避免支撑发生整体屈... 相似文献
20.
This paper is Part II of a two‐part paper describing a full‐scale 3‐story 3‐bay concrete‐filled tube (CFT)/buckling‐restrained braced frame (BRBF) specimen tested using psuedo‐dynamic testing procedures. The first paper described the specimen design, experiment, and simulation, whereas this paper focuses on the experimental responses of BRBs and BRB‐to‐gusset connections. This paper first evaluates the design of the gusset connections and the effects of the added edge stiffeners in improving the seismic performance of gusset connections. Test results suggest that an effective length factor of 2.0 should be considered for the design of the gusset plate without edge stiffeners. Tests also confirm that the cumulative plastic deformation (CPD) capacity of the BRBs adopted in the CFT/BRBF was lower than that found in typical component tests. The tests performed suggest that the reduction in the BRB CPD capacities observed in this full‐scale frame specimen could be due to the significant rotational demands imposed on the BRB‐to‐gusset joints. A simple method of computing such rotational demands from the frame inter‐story drift response demand is proposed. This paper also discusses other key experimental responses of the BRBs, such as effective stiffness, energy dissipation, and ductility demands. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献