State of the art of buckling-restrained braces in Asia

This paper presents a summary of buckling-restrained braces (BRBs). BRBs show the same load-deformation behavior in both compression and tension and higher energy absorption capacity with easy adjustability of both stiffness and strength. Research and developments of various types of BRBs with different configurations in Asia, especially in Japan, are introduced. Analyses and experiments are illustrated to show the conditions necessary for restraining steel braces from buckling. Some key issues of BRB configurations, such as gap and debonding processing between core braces and encasing members, contraction allowance in BRBs and necessary clearances between restraining panels and surrounding frames, BRB projection stiffening approaches to prevent it from buckling, are also described. Based on initial deflections of core braces, both stiffness and strength requirements of encasing member to prevent buckling of core brace are given. Applications for both new high-rise steel buildings and the seismic retrofit of existing buildings show good prospects of using BRBs.     

屈曲约束支撑中钢芯长度的试验优化分析

当钢结构承受侧向荷载时,常采用中心支撑框架。然而,受扭和受压时支撑的滞回性能是不对称的。当受压时,这种框架的强度会持续退化,故采用屈曲约束支撑解决这个问题。屈曲约束支撑的钢芯长度对整体性能影响很大,因为它直接影响着杆件的耗能能力。屈曲约束支撑相当于阻尼,可耗散地震能量,尤其当作为支撑中的"保险"时。短的改进屈曲约束支撑可称为阻尼屈曲约束支撑,好比沿着支撑构件设置了阻尼。制作这种阻尼屈曲约束支撑,并进行试验及分析。对核心板和节点的局部改进,提出了一些建议。     

一字形全钢防屈曲支撑耗能性能试验研究

对一种新型防屈曲支撑进行性能试验研究。该种防屈曲支撑（以下称一字形全钢防屈曲支撑）的内核为一字形钢板,外约束单元为双腹板工字形钢,中间用薄橡胶作为无黏结材料。通过对8个一字形全钢防屈曲支撑试件进行轴向循环往复加载试验,研究了防屈曲支撑的耗能性能以及不同芯材特性、支撑长度对其耗能性能的影响。结果表明：一字形全钢防屈曲支撑的构造合理,所有试件的滞回曲线稳定饱满;芯材特性和支撑长度对于该种防屈曲支撑的耗能性能均有较大影响;以SLY225为芯材的防屈曲支撑,其耗能性能、低周疲劳性能与塑性变形能力均明显优于以SN490B为芯材的防屈曲支撑;SLY225能提供45%以上的附加有效阻尼比;增加支撑长度,防屈曲支撑的塑性变形能力与低周疲劳性能均有所下降。     

双阶屈服屈曲约束支撑框架小震参数分析

为了弥补常规屈曲约束支撑在多遇地震作用下处于弹性状态,不能发挥消能减震作用的不足,提出了一种将金属套管阻尼器与屈曲约束支撑组合形成的双阶屈服屈曲约束支撑,经试验验证其具有良好、稳定的小震及中大震下的滞回特性。在小震作用下,金属套管阻尼器屈服消能,屈曲约束芯板保持弹性承载。借助有限元软件ETABS建立了一系列双阶屈服屈曲约束支撑框架模型,通过改变支撑与框架刚度比、阻尼器与芯板的轴向刚度关系以及套管阻尼器的屈服比例,对各模型进行小震作用下的动力弹塑性分析,将各模型基底剪力和最大层间位移角与相应的常规屈曲约束支撑框架的分析结果进行对比。结果表明:双阶屈服屈曲约束支撑与支撑芯板的轴向弹性刚度比取2左右,阻尼器屈服比例取0.3左右时,可取得较好的减震效果; 双阶屈服屈曲约束支撑的参数取值改变,对降低结构地震响应的影响趋势不因支撑与框架刚度比不同而改变; 当支撑刚度贡献较大时,相较常规屈曲约束支撑,双阶屈服屈曲约束支撑的设置能降低结构的层间位移角,若要同时降低基底剪力,阻尼器屈服比例不宜高于0.3。     

Experimental investigation of hybrid buckling-restrained braces

Though a buckling-restrained brace (BRB) has good seismic performance, it cannot dissipate energy under wind loads or weak earthquakes because its core does not yield. A hybrid buckling-restrained brace (H-BRB), which is a type of hybrid damping system consisting of a BRB member and a viscoelastic damper, has been proposed to improve the wind-resisting performance of the standard BRB. In order to evaluate the wind and seismic performance of the H-BRB system, two H-BRB specimens and one BRB specimen were tested in this study. The variable for the wind performance test was the shear action mechanism of the viscoelastic damper with and without a side connection plate, and the variable for the seismic performance test was whether a separation occurred between the steel tube and a stopper after the yielding of the steel core. The wind performance test showed that H-BRB’s mechanism could be realized only when the viscoelastic damper operated with double shear action. Also, the seismic performance test demonstrated that H-BRB could satisfy the required performance when the tube and stopper were separated after the core’s yielding.     

轻质组装墙板内置钢板支撑滞回性能试验研究

为改善墙板内置钢板支撑的延性,避免钢筋混凝土墙板局部冲切破坏,便于检修内置支撑和减小墙板自重,提出了轻质组装墙板。通过对6个组装墙板内置钢板支撑的试验研究,考察了支撑和墙板的厚度、支撑与墙板间的间隙等构造对支撑滞回性能的影响。试验表明,轻质组装墙板内置Q235钢板支撑具有良好的延性和耗能能力。总体上,墙板内置支撑破坏前骨架曲线呈双折线,支撑屈服后因钢材应变硬化以及支撑和墙板间摩擦等因素,支撑的承载力随侧移的增加而增大。达最大侧移角约1/25时,受拉承载力调整系数范围为1.36～1.61。侧移角在1/25以内时,受压承载力调整系数均小于1.3,支撑的轴向累积非弹性变形能力远大于200,均满足美国ANSI/AISC 341-16的要求。试件最终因内置支撑受拉断裂而破坏,破坏前滞回曲线饱满稳定。组装墙板保持完好,可重复利用。支撑与墙板间留置适宜间隙后,受压支撑在墙板孔壁内仅发生微幅多波弯曲变形,避免了墙板局部破坏。当仅考虑支撑附件的主钢管和开孔钢板简化计算墙板绕钢板支撑弱轴的欧拉临界力,墙板的欧拉临界力与内置支撑的最大轴向受压承载力之比(约束比)达1.15～2.42,墙板内置支撑不发生受压整...     

双管式挫屈束制(屈曲约束)支撑之耐震行为与应用

挫屈束制(屈曲约束)支撑一般是由十字型或一字型钢板构成之核心单元加上钢管混凝土构成之束制(约束)单元所组成。由于单核心断面之挫屈束制支撑在与构架接合时每一端需使用八片续接板及两套的螺栓，造成接合部分较长且易发生挫屈(屈曲)，为了改善此种挫屈束制支撑与接合，相关研究已发展出以双T型核心配双钢管或双钢板核心配双钢管而组成之双钢管型挫屈束制支撑构件，并已成功地在台大完成一系列之试验，本研究进一步针对大尺寸之单层挫屈束制支撑构架进行试验。研究目的包括：(1)探讨支撑具不同核心长度比例构架之试验与解析行为；(2)研究挫屈束制支撑核心应变与楼层侧位移角之关系；(3)提供含挫屈束制支撑构架之分析与设计建议。由i组V型双钢板双钢管挫屈束制支撑构架之试验显示，支撑核心之极限应变可利用楼层的最大侧位移角需求，以简单的几何关系及支撑核心长度与工作点间长度之比值计算而得，试验结果亦显示，在构架产生最大侧位移角时支撑之核心拉应变会大于相邻支撑之核心压应变，显示两相邻支撑之轴拉力与轴压力在试体巾有互相平衡之趋势，而不会发生最大轴压力显著大于最大轴拉力的现象。     

Experimental investigation on buckling‐restrained braces using mortar‐filled steel tubes with steel lining channels

A new type of buckling‐restrained braces (BRBs) using mortar‐filled steel tubes with steel lining channels is proposed to reduce the frictional force between the core member and the restraining member. After covering the core plate with the unbonding material, steel lining channels are set on the surface along the longitudinal direction, thus transforming the contact property between the core plate and the restraining member from steel–mortar interface to steel–steel interface. First, comparative cyclic tests are conducted on two new BRBs with steel lining channels and one conventional BRB. All the specimens exhibit stable hysteretic performance without visible global or local instability prior to failure. It is confirmed that the steel lining channels can improve the interface evenness between the core plate and the restraining member, reduce the compression strength adjustment factor, and improve the low‐cycle fatigue behavior and energy dissipation capacity of the BRB. Furthermore, the analytical model for the local stability of the restraining tube is proposed when the core plate buckles about the strong axis, and the corresponding practical design criteria are provided. The influence of various core plate layouts on the local stability of the restraining tube is finally investigated.     

Tests of hysteretic behavior for unbonded steel plate brace encased in reinforced concrete panel

Quasi-static tests for ten pieces of the unbonded steel plate brace encased in reinforced concrete panel, which is referred to as the panel buckling-restrained brace (panel BRB), have been carried out. The effects of some constructional details, such as unbonded material, clearance between the panel and the brace, configuration of the steel bar and the edge reinforcement, effective width of the panel, etc., on the hysteretic behavior of the panel BRBs are examined. The results indicate that the panel BRBs with evener unbonded materials, smaller clearance and additional steel bars and ties along the encased braces exhibit better ductility and energy dissipation capacity than the others. The brace under compression appears to exhibit small amplitude flexural buckling with multiple waves, and its ultimate axial force exceeds its yield load capacity significantly due to strain hardening and frictional action. All specimens of panel BRB exhibit a stable performance under the quasi-static loading until local failure of the panel occurs by either flexure or punching shear. The results also reveal that, with the same construction details mentioned above, the hysteretic behavior of the specimens with the effective width panel almost matches that of the specimens with normal weight concrete panel, however, the former kind of panel BRB would be advantageous in the aseismic performance of the buildings because of its lighter weight.     

铝合金芯板防屈曲耗能支撑滞回性能研究

为开发轻质高效的结构耗能阻尼器并将其应用于空间结构振动控制,利用国产铝合金作为防屈曲耗能支撑的核芯材料,并对研制的6个支撑试件进行了拟静力试验。按照稳定理论设计的试件在试验中未发生整体失稳,铝芯板与约束钢管间预留一定间隙并填充锂基润滑脂以消除套箍效应和减小界面摩擦。试验结果显示：支撑在受拉和受压时都能屈服而不屈曲,铝芯板应变强化现象明显,滞回曲线稳定饱满,有较高的耗能能力,其拉压峰值不均匀系数不超过1.3。基于Chaboche钢材循环塑性本构模型,通过试验数据对相关铝材模型参数进行了标定,并将其应用于防屈曲支撑的有限元分析,计算结果与试验曲线吻合良好,相关模型参数能够进一步应用于结构抗震弹塑性分析。     

屈曲约束支撑体系的应用与研究进展(Ⅱ)

屈曲约束支撑框架体系(BRBF)是新近发明并逐渐得到应用的一种框架体系。因为屈曲约束支撑(BRB)在受拉和受压时都可屈服而不屈曲,因此克服了传统支撑体系的缺点。第二部分简要介绍了SEAOC-AISC提出的反复加载试验要求,介绍了BRB各组成部分、BRB构件本身及BRBF体系的性能。以及BRBF的设计方法。     

Pall型摩擦阻尼支撑体系试验研究

鉴于Pall型摩擦阻尼普通支撑会对框架边柱产生附加轴力,考虑采用防屈曲支撑来代替普通支撑,使支撑充分发挥作用,同时不会对边柱产生增长的附加轴力,为防屈曲支撑在Pall型摩擦阻尼支撑体系中的应用奠定基础.由于Pall型摩擦阻尼器滞回特性不受支撑屈曲力影响的特性,故采用普通钢板来代替防屈曲支撑进行Pall型摩擦阻尼支撑体系试验研究,同时对此支撑体系在考虑几何非线性情况下进行有限元AN-SYS仿真分析.对比试验结果和仿真分析结果,表明试验结果与仿真分析结果得出的Pall型摩擦阻尼器摩擦力和支撑内力的变化规律基本相同,为下一步采用防屈曲支撑体系进行试验研究奠定基础.     

鄂尔多斯某商业广场屈曲约束支撑安装焊缝质量控制研究

屈曲约束支撑体系是新近发明并逐渐在日本、欧美得到应用的一种抗震耗能支撑体系。近年，国内将屈曲约束支撑应用于新建和改造加固的工程亦逐渐增多。因为屈曲约束支撑在受拉和受压时都可屈服而不屈曲，因此克服了传统支撑体系的缺点。大量研究表明，合理的节点设计和良好的节点施工质量是确保屈曲约束支撑发挥耗能支撑作用的关键。探讨钢结构屈曲约束支撑焊缝施工质量控制过程中存在的问题。     

屈曲约束支撑体系的应用与研究进展(Ⅰ)

屈曲约束支撑框架体系(BRBF)是新近发明并逐渐得到应用的一种抗震框架体系。因为屈曲约束支撑(BRB)在受拉和受压时都可屈服而不屈曲,因此克服了传统支撑体系的缺点。本文分两部分,第一部分主要介绍其基本原理和各组成部分的概况、BRBF的特点,还简要介绍了该体系在各国家和地区应用和研究的进展情况。     

某小学教学楼的屈曲约束支撑抗震加固设计

屈曲约束耗能支撑在拉、压两种受力状态下都能达到屈服,是一种集抗侧力和耗能为一体的耗能减震构件。结合学校加固工程特点和支撑受力性能,应用屈曲约束耗能支撑在某平面严重不规则的教学楼中进行加固设计,通过反应谱以及非线性时程分析方法,比较研究采用支撑加固前后教学楼相关信息。结果显示,小震作用下支撑可很好地调整原有结构抗扭和抗侧刚度,大震作用下支撑能有效消耗地震能量,提高结构承载力,加固效果明显。     

Wind‐induced vibration control of tall buildings using hybrid buckling‐restrained braces

A buckling‐restrained brace (BRB) is a system with excellent earthquake‐proof performance, but it does not dissipate energies caused by the load from weak earthquakes or winds. A hybrid BRB (H‐BRB), which improved the performance of the BRB, is a type of composite damper system consisting of a BRB and a viscoelastic damper. To explain the wind‐induced vibration control performance of H‐BRB, a 40‐story steel building was designed and used as an analysis model in this study, on the basis of the damping ratio from a structural performance test, using normal steel braces, BRB and H‐BRB. In addition, to evaluate the optimal location of H‐BRB, a time‐history analysis of four models was conducted in the study. For such time‐history analysis, wind‐load data in a 10‐year recurrence interval, which were calculated from the wind tunnel test, were used. The result of the time‐history analysis showed that H‐BRB is effective in improving both the lateral stiffness and serviceability of a building using the existing BRB. It also confirmed that it is most effective to position H‐BRBs mainly on the lower stories. Copyright © 2012 John Wiley & Sons, Ltd.     

开孔钢板装配式屈曲约束支撑钢框架抗震性能试验研究

为研究开孔钢板装配式屈曲约束支撑（buckling-restrained brace,BRB）钢框架的抗震性能及框架平面外变形对其抗震性能的影响,对两个相同设计的单层单跨单斜式开孔钢板装配式BRB钢框架分别就是否考虑框架平面外变形情况下进行了拟静力试验,并对相同设计的开孔钢板装配式BRB构件进行了拟静力试验。结果表明：不考虑框架平面外变形和考虑框架平面外变形10mm的开孔钢板装配式BRB钢框架均表现出良好的滞回耗能性能,滞回曲线饱满且基本对称,满足GB 50011—2010《建筑抗震设计规范》最大弹塑性层间位移角1/50的限值要求;框架平面外变形10mm对开孔钢板装配式BRB钢框架平面内抗震性能影响很小,其弹性水平刚度、层间屈服剪力和层间最大剪力受框架平面外变形的影响略为降低,变化范围均在5%以内;框架平面外变形10mm对BRB轴向变形的影响很小,框架中开孔钢板装配式BRB和开孔钢板装配式BRB构件均具有良好的滞回性能,约在1/720层间位移角时先于钢框架进入屈服状态,发挥耗能作用,其滞回曲线饱满,延性良好,累积塑性变形能力系数均大于600,完全满足ANSI /AISC 341-10中要求的大于200的要求。     

人字形无黏结内藏钢板支撑剪力墙拟静力试验研究

通过对6个人字形无黏结内藏钢板支撑剪力墙试件的拟静力试验研究,对无黏结材料及支撑与墙板的间隙、墙板内钢筋配置、墙板端部加强构造以及钢板支撑周围有效宽度范围内采用普通混凝土,其余部分采用轻骨料混凝土的有效宽度墙板等因素对试件滞回性能的影响进行考察。试验结果表明,无黏结材料的均匀包裹、支撑与墙板间留有较小的间隙以及沿支撑轴向加密纵横向钢筋和拉结筋等构造措施,可以显著提高墙板局部抗弯和抗冲切承载力,改善试件的延性和耗能能力。支撑受压失稳时呈多波微幅弯曲变形状态,随压力增大,失稳半波数增多,支撑对墙板的局部冲切作用随之增大,使墙板局部弯曲或冲切破坏。直至破坏前,试件滞回曲线饱满稳定,骨架曲线基本呈现两折线的形式。试验还表明,当其他构造相同时,采用有效宽度墙板的试件和整个墙板均由普通混凝土制成的试件的滞回性能几乎相同,但前者自重轻,有利于墙板的安装和结构抗震。     

防屈曲支撑-钢筋混凝土框架结构基于能量平衡的抗震塑性设计

为确定防屈曲支撑在结构中的布置方式以使结构抗震性能充分发挥,提出了基于能量平衡的防屈曲支撑 钢筋混凝土框架结构抗震塑性设计方法。构建了结构的“强柱弱梁”整体屈服机制,采用侧力比将总结构体系离散为防屈曲支撑体系和纯框架体系,并建立了结构的双线性能力曲线。基于能量平衡方法计算结构的设计基底剪力并分别得到支撑体系和框架体系的设计侧向力,进而完成支撑的截面设计。按照塑性内力分配机制和考虑支撑屈服后性能,计算梁柱构件内力需求。以一幢5层结构为例,分别设计了不同侧力比的14个结构模型,对比了基底剪力、防屈曲支撑面积和梁柱钢筋用量等。通过22条地震波下的弹塑性时程分析,研究了不同侧力比结构的最大层间位移角、屈服机制、楼层剪力比、支撑最大位移延性、累积位移延性和结构残余层间位移角。分析结果表明：所提出的方法能实现结构的预期失效模式,并满足结构的抗震性能要求,并建议设计侧力比选取在0.3~0.5之间。