基于ANSYS约束屈曲支撑框架结构分析

传统的耗能支撑框架结构具有较好的经济性,但是,在中震和强震时,支撑会发生受压屈曲。利用ANSYS模拟约束屈曲支撑框架在地震作用下的结构响应,采用理想弹塑性模型模拟屈曲约束支撑的滞回性能,分别在中震烈度和大震烈度下,对一般框架结构和约束屈曲支撑框架结构进行非线性时程分析,得到结构响应。分析结果表明,约束屈曲支撑结构减震效果良好。     

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。     

一种新型屈曲约束支撑的研制与试验研究

屈曲约束支撑由于具有受压不会屈曲失稳的性质,与含有普通支撑的框架相比,含有屈曲约束支撑的框架具有更好的耗能作用。然而常规屈曲约束支撑的芯材和无粘结材料往往采用特殊材料制成,加工制作成本较高,不利于工程推广使用。为了避免常规屈曲约束支撑存在的上述缺陷,自主研制开发了一种带有缝隙和防滑凸起的新型屈曲约束支撑。着重介绍了这种新型屈曲约束支撑的构造和特点,并对6个支撑试件进行了包括标准加载和循环加载在内的低周反复加载试验。结合试验现象,分析、探讨了支撑的破坏机理。对这种屈曲约束支撑的弹性刚度、塑性刚度、屈服荷载和屈服位移等力学指标进行了测定,并将测定结果与基于双线性模型计算出的理论值进行了比较;同时参照我国规范和FEMA356,探讨了这种屈曲约束支撑的耗能能力。试验结果表明,这种新型屈曲约束支撑各项力学指标实测值与理论值符合较好,耗能能力稳定,满足国内外规范的要求,达到了工程应用的标准。     

基于位移的屈曲约束支撑混凝土框架结构抗震设计方法

采用基于位移的抗震设计方法对屈曲约束支撑混凝土框架进行抗震设计,采用线性侧移曲线,基于弹塑性位移反应谱求得结构的屈服基底剪力,对屈曲约束支撑进行设计。按照此方法分别设计5层和10层屈曲约束支撑混凝土框架结构,并对设计结果进行Pushover分析和动力时程分析。结果表明:屈曲约束支撑可有效控制结构的位移,结构的侧移模式与假定基本一致,可实现屈曲约束支撑混凝土框架的抗震性能设计。     

内嵌双阶段装配式防屈曲支撑的钢框架-支撑结构抗震性能评估

为研究新型内芯可更换的双屈服点装配式防屈曲约束支撑对装配式钢框架-支撑结构抗震性能的影响，首先采用有限元软件Perform-3D建立了普通支撑、防屈曲支撑和新型内芯可更换的双屈服点装配式防屈曲约束支撑的有限元模型，并验证了建模方式的准确性；之后在此基础上建立内嵌新型内芯可更换的双屈服点装配式防屈曲支撑的钢框架-支撑结构有限元模型，并采用弹塑性时程分析方法对普通钢框架结构、钢框架-普通支撑结构、钢框架-防屈曲支撑结构、内嵌新型双屈服点装配式防屈曲支撑的钢框架-支撑结构的抗震性能展开研究。分析结果表明：Perform-3D能准确模拟普通钢支撑、普通防屈曲支撑及新型内芯可更换的双屈服点装配式防屈曲支撑；内嵌新型双屈服点防屈曲支撑的钢框架-支撑结构在最大层间位移角和结构顶层位移、基底剪力上均优于其他结构，新型内芯可更换的双屈服点装配式防屈曲约束支撑在地震作用下起到了重要的作用，它主要通过新型内芯可更换的双屈服点装配式防屈曲约束支撑来耗能，这说明内嵌新型内芯可更换的双屈服点装配式防屈曲支撑的钢框架-支撑结构具有良好的抗震性能。     

屈曲约束耗能支撑在教学楼加固工程中的应用

汶川地震中大量教学楼由于抗震能力不足而倒塌,造成了巨大的灾难和损失,为此,对学校建筑进行抗震加固异常迫切。屈曲约束耗能支撑在受拉和受压两种状态下都能达到屈服,克服了普通支撑受压屈曲的问题,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以及屈曲约束耗能支撑的性能,提出了屈曲约束耗能支撑在教学楼加固中的设计、施工方法。通过弹性以及弹塑性分析方法研究了采用屈曲约束支撑加固后教学楼的抗震性能。     

防屈曲约束支撑对异形柱框架结构抗震性能增强作用的试验研究

对两榀有无人字形防屈曲约束支撑的异形柱框架进行拟静力试验,研究防屈曲约束支撑异形柱框架结构的破坏形态、滞回特性、承载能力、延性性能、耗能能力等抗震性能指标。结果表明:人字形防屈曲约束支撑异形柱框架的滞回曲线呈现梭形,无撑异形柱框架的滞回曲线有明显捏拢现象,人字形防屈曲约束支撑可以使框架各层延性系数分布更加合理;有撑框架与无撑框架结构相比,有撑框架初始整体刚度提高了53.49%,极限荷载提高了1.50倍,整体极限位移角增大了近3倍。防屈曲约束支撑推迟了梁柱节点塑性铰的产生时间,改变了异形柱框架的屈服机制,使结构发生两阶段屈服,基于此提出了以人字形防屈曲约束支撑达到屈服时作为有撑异形柱框架结构的屈服点,以期更好地反映结构的抗震性能,更符合有撑框架的实际屈服机制。防屈曲约束支撑使异形柱框架结构累积损伤程度减轻,屈服阶段至破坏前,组合结构黏滞阻尼系数基本稳定在0.21左右,没有出现大幅度降低。     

不同间隙全钢圆套圆防屈曲支撑的抗震性能研究

支撑-框架体系在设防烈度和罕遇地震作用下其传统支撑易较早发生受拉、受压屈服,甚至发生大幅值屈曲失稳破坏,不利于框架结构的承载和能量耗散。全钢圆套圆型防屈曲支撑(称圆套圆防屈曲支撑)可代替传统支撑为支撑-框架体系提高承载能力和耗能能力。该圆套圆防屈曲支撑主要是由承力耗能内圆管(称核心管)与约束核心管屈曲变形的外圆管(称约束外管)构成的一种特殊耗能支撑。利用静力非线性分析方法对不同间隙的圆套圆防屈曲支撑力学性能进行分析,包括滞回曲线、抗震性能指标CPE、骨架曲线以及刚度退化等。结果表明:间隙取值为2 mm时,圆套圆防屈曲支撑比传统支撑受压承载能力提高了55. 4%,滞回耗能提高了80. 2%,抗压刚度提高了111%。圆套圆防屈曲支撑显著改善了传统支撑受压易屈曲的缺点,且在受力性能、滞回耗能、造价以及制作工艺等各方面表现优异。     

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。     

高地震烈度区混凝土框架-屈曲约束支撑结构应用研究

结合某高地震烈度区工程,对混凝土框架-屈曲约束支撑结构的抗震设计方法以及相关问题进行了研究。分析了混凝土框架-屈曲约束支撑结构的最大适用高度、合理的附加刚度、适宜的层间位移角限值,并通过罕遇地震下的弹塑性时程分析考察结构的抗震性能。结果表明:混凝土框架-屈曲约束支撑结构的抗震性能优于纯混凝土结构,主体混凝土框架更容易成为"损伤可控结构",实现震后可恢复性;建议混凝土框架-屈曲约束支撑结构的最大适用高度按混凝土框架结构和框架-抗震墙结构二者最大适用高度的平均值采用;为控制主体混凝土框架的损伤,屈曲约束支撑按刚度分配的地震倾覆力矩宜大于结构总地震倾覆力矩的50%,在各层承担的楼层地震剪力不宜小于30%;建议屈曲约束支撑的附加刚度比控制在1左右,延性系数不小于3;混凝土框架-屈曲约束支撑结构相对于混凝土框架结构的层间位移角限值,在多遇地震下应根据支撑不屈服的要求做适当调整。     

Experimental optimization studies on steel core lengths in buckling restrained braces

Concentric braced frames are commonly used in steel structures to withstand lateral forces. However, brace hysteretic behavior is asymmetric in tension and compression. These frames typically exhibit substantial strength deterioration when loaded in compression. Consequently, the concept of Buckling Restrained Brace (BRB) has been introduced to overcome this deficiency.The length of a BRB steel core could have a significant effect on its overall behavior since it directly influences the energy dissipation of the member. Furthermore, BRB could be effectively utilized as a damper to dissipate seismic input energy, particularly when used as a fuse within the brace in a frame. Modified BRBs with shorter lengths may be called damper BRBs, because they function as if a typical damper is utilized along any brace member. These damper BRBs are fabricated and tested in this study both experimentally and analytically. Useful insights into local retrofitting of core plates and connections are also provided.     

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.     

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。     

耦合框架平面外变形钢板装配式屈曲约束支撑#br# 钢筋混凝土框架抗震性能试验研究

为了研究双向地震作用下屈曲约束支撑（Buckling-restrained brace,BRB）钢筋混凝土框架平面内抗震性能以及BRB与钢筋混凝土框架在平面外方向的相互作用,考虑框架平面外变形、节点板平面外刚度和屈曲约束支撑外伸段平面外刚度的影响,对4个钢板装配式屈曲约束支撑钢筋混凝土框架及1个钢筋混凝土空框架进行了平面内拟静力试验研究。研究结果表明：①耦合框架平面外变形的BRB钢筋混凝土框架和无框架平面外变形的BRB钢筋混凝土框架平面内层间剪力与层间位移滞回曲线饱满稳定,具有良好的抗震性能;②框架平面外变形在一定程度上减小了钢板装配式BRB钢筋混凝土框架平面内初始水平刚度和承载力,增大了钢板装配式BRB和节点板平面外变形量;③节点板面外刚度的提高增加了框架节点平面外作用力;④钢板装配式BRB面外刚度的增加能减小自身平面外变形,减小其对钢筋混凝土框架平面外作用力。     

自复位摩擦耗能支撑框架的抗震性能分析

自复位摩擦耗能支撑(SCFED)是一种兼具耗能能力与自定心能力的新型支撑。本文将SCFED应用于一9层Benchmark钢框架,采用OpenSEES有限元软件,进行了非线性静力推覆分析(Pushover)和非线性动力时程分析,通过与屈曲约束支撑(BRB)框架结构的对比,研究了SCFED框架结构的抗震性能。结果表明:SCFED框架的最大层间位移角较BRB框架小,且沿楼层高度分布更为均匀;BRB框架平均残余层间位移角约为最大位移角的10%~20%,而SCFED框架的残余位移角仅为最大位移角的1%~2%,表明SCFED能有效控制结构的残余变形;由于SCFED在自复位时的刚度转换较为剧烈,导致SCFED框架的层加速度比BRB框架大。     

钢管混凝土减震框架与钢管混凝土框架-剪力墙结构的对比试验研究

设计两榀比例为1:4、梁柱构件尺寸相同的试件:一榀为设置新型三重钢管防屈曲支撑的钢管混凝土减震框架,一榀为普通钢管混凝土框架-剪力墙结构。对两个试件进行反复荷载作用下的抗震性能试验,对比分析两种结构的破坏特征、滞回性能、骨架曲线、强度和刚度退化、耗能能力和关键点应变等抗震性能指标。试验结果表明:钢管混凝土减震框架结构具有与钢管混凝土框架-剪力墙结构相当的承载力,并在变形能力、延性和耗能能力等方面均有明显的提高,对刚度退化和强度退化也有明显的缓解,具有更合理的受力性能和破坏机制,新型三重钢管防屈曲支撑起到良好的耗能减震作用,有效地改善钢管混凝土框架的抗震性能。     

Compressive behavior of dual-gusset-plate connections for buckling-restrained braced frames

This work conducts compression tests and finite element analyses for steel dual-gusset-plate connections used for buckling-restrained braced frames (BRBFs). Compared to a single-gusset-plate connection, dual gusset plates sandwiching a BRB core reduce gusset plate size, eliminate the need for splice plates, and enhance connection stability under compression. The experimental program investigated ultimate compression load by testing ten large dual-gusset-plate connections. Out-of-plane deformation of the gusset plate in the test resembled that of a buckled gusset plate with low bending rigidity provided by the BRB end. The general-purpose nonlinear finite element analysis program ABAQUS was applied for correlation analysis. A parametric study of the dual-gusset-plate connection was performed to study the effects of plate size, presence of centerline stiffeners, and beam and column boundaries on ultimate compression load. The ultimate compression load of the dual-gusset-plate connection could not be predicted based on the AISC-LRFD approach due to beam flange out-of-plane deformation. The ultimate compression load of the dual-gusset-plate connection was reasonably predicted using a column strip length from the Whitmore section to the workpoint of the beam and column centerlines and a buckling coefficient of K = 2.     

Experimental study on seismic performance of CFST frame structures with energy dissipation devices

Three model structures of concrete filled steel tubular (CFST) frame with a scaling ratio of 1:4 were designed and tested in the present study. The structural elements of the three model structures had same dimensions. Two of them were installed with a new triple-steel tube buckling-restrained brace (BRB). The seismic behaviors of the structures were evaluated by testing them with combined vertical constant compression and lateral cyclic loads. The structural performance, such as the hysteretic behavior, skeleton curve, strength degradation, stiffness degradation, energy dissipation capacity and strains at different locations of the model structures with and without BRB was discussed in detail. The results show that the CFST frame with BRB significantly improved the load bearing capacity, the deformability and the energy dissipation capacity, with the strength and stiffness degradation being obviously reduced. The CFST frame with BRB has preferable mechanical behavior and failure mode. It was verified that the new triple-steel tube BRB improves the seismic performance of CFST frame structures.     

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。     

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.