Seismic performance of Y‐type eccentrically braced frames combined with high‐strength steel based on performance‐based seismic design

In the Y‐type eccentrically braced frame structures, the links as fuses are generally located outside the beams; the links can be easily repairable or replaceable after earthquake without obvious damage in the slab and beam. The non‐dissipative member (beams, braces, and columns) in the Y‐type eccentrically braced frames are overestimated designed to ensure adequate plastic deformation of links with dissipating sufficient energy. However, the traditionally code design not only wastes steel but also limits the application of eccentrically braced frames. In this paper, Y‐type eccentrically braced steel frames with high‐strength steel is proposed; links and braces are fabricated with Q345 steel (the nominal yield stress is 345 MPa); the beams and columns are fabricated with high‐strength steel. The usage of high‐strength steel effectively decreases the cross sections of structural members as well as reduces the construction cost. The performance‐based seismic design of eccentrically braced frames was proposed to achieve the ideal failure mode and the same objective. Based on this method, four groups Y‐type eccentrically braced frames of 5‐story, 10‐story, 15‐story, and 20‐story models with ideal failure modes were designed, and each group includes Y‐type eccentrically braced frames with ordinary steel and Y‐type eccentrically braced frames with high‐strength steel. Nonlinear pushover and nonlinear dynamic analyses were performed on all prototypes, and the near‐fault and far‐fault ground motions are considered. The bearing capacity, lateral stiffness, story drift, link rotations, and failure modes were compared. The results indicated that Y‐type eccentrically braced frames with high‐strength steel have a similar bearing capacity to ordinary steel; however, the lateral stiffness of Y‐type eccentrically braced frames with high‐strength steel is smaller. Similar failure modes and story drift distribution of the prototype structures designed using the performance‐based seismic design method are performed under rare earthquake conditions.     

Y形偏心支撑高强钢框架结构抗震性能

在Y形偏心支撑高强钢框架结构抗震性振动台试验的基础上,建立了试验试件的有限元模型,并验证了分析的正确性。设计了一个9层的Y形偏心支撑高强钢框架结构,以耗能梁段长度、耗能梁段腹板高厚比、高跨比为参数,对9层结构进行了非线性动力时程分析,研究了以上参数对结构抗震性能的影响。研究结果表明,改变耗能梁段长度、高跨比对结构层间侧移、耗能梁段性能、框架柱弯矩、耗能能力均有不同程度的影响,对框架柱轴力、基底剪力无显著影响;改变耗能梁段腹板高厚比对结构耗能能力有影响,对结构层间侧移、耗能梁段性能、框架柱受力、基底剪力无显著影响,并给出了相关设计建议。     

Y形偏心支撑-高强钢框架结构抗震性能试验研究

为研究Y形偏心支撑-高强钢框架结构抗震性能,在已完成的1∶2缩尺3层模型结构振动台试验的基础上,重新设计了耗能梁段,并对该结构再次进行振动台试验。试验中选取El Centro波、Taft波和兰州波作为地震动输入并考虑7度多遇到9度罕遇的地震水准,分析了结构在水平地震作用下的动力特性、加速度响应、位移响应、应变响应、剪力分布等,并与已有试验结果进行了对比。通过ABAQUS建立了有限元分析模型,与试验结果进行对比。结果表明：该结构在多遇地震作用下处于弹性状态,在罕遇地震作用下表现为耗能梁段的局部破坏;耗能梁段破坏后,结构刚度大幅下降,但未发生倒塌;在多遇地震和罕遇地震作用下,结构的最大层间位移角满足抗震规范层间位移角限值的相关要求;在罕遇地震作用下,耗能梁段进入塑性状态而进行耗能,其他构件仍保持弹性状态;所建立的有限元模型可以有效模拟振动台试验结果。     

轴心压力对K型偏心支撑钢框架抗震性能的影响

对偏心支撑钢框架进行了介绍,简述了偏心支撑钢框架的优点及应用,通过ANSYS有限元程序,研究了轴心压力对K型偏心支撑钢框架抗震性能的影响,得出了设计轴压比应控制在0.6以下才能保证结构的抗震性能充分发挥的结论.     

Seismic performance of eccentrically braced frame with vertical link using PBPD method

There are special guidelines to design the structures resistant to earthquake forces; parameters such as conditions of the site, seismicity of the site, importance of the structure and the type of the structure are the main effective factors. Consideration of these parameters in calculation and distribution of the earthquake forces are significantly different in various design codes. In most of these design codes, the computation and distribution of earthquake forces are based upon the elastic structural analysis. In this approach, the real behavior of structure is not considered and it may consequently sustain big displacements and irretrievable damages. Therefore, a new design method has been utilized in this paper by which the base shear and its distribution in the height of the structure are calculated according to the plastic behavior of structure and takes advantage of energy balance. The latter is known as performance‐based plastic design method. The study of the behavior of eccentrically braced frames with vertical links while undertaking earthquake loads using performance‐based plastic design method is the main purpose of this study. It is also worthy of notion that the frames are designed using a capacity design method. In addition, the results are compared with those of the International Building Code 2009 method; the results demonstrate that the plastic hinges, the interstory drifts and plastic rotation of links are distributed more uniformly in the height of frames designed by the suggested method compared to International Building Code 2009. Copyright © 2012 John Wiley & Sons, Ltd.     

多层高强钢组合Y形偏心支撑钢框架抗震性能试验研究

为研究高强钢组合Y形偏心支撑钢框架结构的抗震性能,进行了一个1∶2缩尺模型的三层结构试件的低周往复加载试验,从结构的承载能力、刚度退化、位移延性、耗能能力及破坏模式等方面评价了结构的抗震性能,试验采用三质点倒三角形比例加载。研究结果表明：高强钢组合Y形偏心支撑结构具有较高的承载能力、较好的位移延性和耗能能力,屈服强度较低的耗能连梁的弹塑性变形耗散了大部分地震能量,而高强钢非耗能构件基本处于弹性受力状态,保证了极限状态下结构的完整性。框架梁与耗能连梁连接节点处受力复杂、应力集中严重,加之楼板对框架梁的约束,该节点处变形较大,使得试件最终在此位置破坏。     

高层偏心支撑钢框架弹塑性地震反应分析

偏心支撑框架与纯框架相比,有更大的抗侧移刚度及极限承载力,与中心支撑框架相比,可有效地降低地震作用.国内外学者对偏心支撑性能做了较多研究,但实际工程中鲜有应用,我国现有钢结构建筑大多为中心支撑框架或纯框架,结合一工程实例,对高层偏心支撑钢框架进行弹塑性时程分析和抗震性能研究.     

V型偏心支撑钢框架抗震性能非线性时程分析

针对V型偏心支撑钢框架的不同耗能梁段长度,运用有限元分析软件SAP2000对相应的算例进行非线性时程分析。通过对构件内力、节点位移等计算结果的分析,并与D型和K型偏心支撑钢框架非线性时程分析的结果进行比较,得到了一些结论,以供工程设计人员参考。     

D型偏心支撑钢框架抗震性能非线性时程分析

针对D型偏心支撑钢框架的不同耗能梁段长度,运用有限元分析软件SAP2000对相应的算例进行非线性时程分析。通过对构件内力、节点位移等计算结果的分析得到了一些结论,以供工程设计人员参考。     

Y型偏心支撑钢框架受力性能有限元分析

建立了四种Y型偏心支撑钢框架有限元模型,对平面模型框架和三种空间模型框架进行了单向加载和循环加载试验,并对比分析了模型框架的屈服强度、极限承载力、侧向刚度、延性和耗能能力等方面的受力性能差异,得到的结果为工程设计提供了参考。     

梁贯通式支撑钢框架体系的强度折减系数研究

基于强度折减系数的抗震设计方法,将增量动力分析（IDA）和能力谱法（CSM）结合,对典型梁贯通式支撑钢框架结构的强度折减系数进行研究。采用结构试验校准后的有限元分析模型对结构进行分析,得到结构性能点。通过比较按照设防烈度弹性设计的基底剪力Ve和按照小震设计的基底剪力Vd得到强度折减系数R。分析表明：支撑与框架柱的配置比例及布置方式会对此类结构的强度折减系数产生影响;适用于7度设防烈度的典型两层结构两种支撑配置比例（CASE1和CASE2一层与二层支撑配置比例分别为3∶1和2∶1）梁贯通式支撑钢框架结构体系的强度折减系数可分别取为3.02和2.54。最后建议了该新型结构体系考虑强度折减系数并基于我国现行规范进行抗震设计的地震作用取值范围。     

与足尺钢框架柔性连接的外挂复合墙板振动台试验研究

为了研究外挂陶粒钢筋混凝土复合墙板和竹筋陶粒混凝土复合墙板(以下均简称复合墙板)的抗震性能,以及连接复合墙板和钢框架的下托上拉式柔性节点的地震反应,通过两幢3层足尺分层装配支撑钢框架的振动台试验,对墙板-节点体系的抗震性能进行了研究。结果表明,复合墙板具有较好的抗震性能,刚度和承载力储备较大;使用竹筋代替斜插钢丝后,对复合墙板抗震性能影响不大,且相对于直插竹筋,斜插竹筋性能更加稳定;下托上拉式柔性节点在试验中出现了滑移、转动和变形,实现了3个方向的位移,对墙板的保护作用明显,兼具刚性和柔性的特点;外挂复合墙板-节点体系减小了钢框架的自振周期,使结构刚度退化减慢,加速度放大系数及层间位移分布更加均匀。该体系应用于低多层建筑时具有优良的抗震性能和震后可恢复性。     

新型装配式钢管混凝土柱-钢筋混凝土梁框撑体系振动台试验研究

结合装配式建筑和钢管混凝土柱-钢筋混凝土梁组合框架结构的优点,提出新型装配式方钢管混凝土柱-钢筋混凝土梁组合框撑体系。为研究该类新型体系的整体抗震性能,设计制作了缩尺比为1/3的6层整体模型,对该模型输入了《建筑抗震设计规范》(GB 50011—2010)所建议的多种烈度下的地震激励,获得了其在相应地震激励作用下的结构响应及破坏形态,分析研究了其整体抗震性能、结构失效路径以及连接节点的可靠性。研究表明：①该类结构体系具有“强钢管混凝土柱-弱钢筋混凝土梁”及“强节点-弱构件”的理想失效路径;②梁的破坏点位于工字型钢接头梁段与钢筋混凝土梁段交界位置,距梁柱节点核心区域有一定距离,从而保证了节点核心区域的完整性;③结构部分楼层在强震下会因斜撑失效而形成薄弱层,造成结构响应的放大。     

高层高强钢组合Y型偏心支撑钢框架结构抗震性能研究

伴随高强钢组合Y型偏心支撑钢框架结构的不断发展与更大范围的运用,为更好地掌握此类框架结构的抗震性能与综合表现,本文围绕该问题进行一系列的深入探究.在具体的分析过程中,首先通过ABAQUS有限元软件创建了相应的运算模型,并和试验结果展开对比分析,明确计算模型的可靠性.然后借助有限元分析软件ETABS建立了10层Y型钢框架...     

Fundamental period of irregular concentrically braced steel frame structures

This paper presents the results of investigation on the fundamental periods of concentrically braced frame (CBF) structures with varying geometric irregularities. A total of 12 CBFs are designed and analyzed. On the basis of the results obtained from vibration theory, equations for the approximate fundamental periods are put forth for CBFs, which take into account vertical and horizontal irregularities. Through statistical comparison, it was found that a three‐variable power model that is able to account for irregularities resulted in a better fit to the Rayleigh data than equations that were dependent on height only. The proposed equations were validated through a comparison of available measured period data for CBFs. These proposed equations will allow design engineers to quickly and to accurately estimate the fundamental period of CBF structures by taking into account irregularities. Copyright © 2013 John Wiley & Sons, Ltd.     

大型火电厂钢结构主厂房铰接中心支撑框架体系的振动台试验研究

为获得铰接中心支撑框架结构体系的抗震性能,以位于抗震设防烈度8度区的某大型火电厂钢结构主厂房横向最不利一榀的煤仓间部分为原型,按1∶12缩尺比例设计制作了试验模型,并对其进行了14种地震工况下的模拟地震作用振动台试验。得到了模型结构的动力特性、阻尼比及其在8度多遇、基本和罕遇烈度下的加速度和位移响应等。结果表明:8度多遇地震作用前后结构第1阶频率为4.59Hz,8度罕遇地震作用后,第1阶频率减小为4.40Hz,但梁柱仍然完好,仅有个别支撑和节点板出现了微小的平面外变形。依据试验与有限元分析结果,推算出试验原型结构在三种地震(E l Centro、CholamShandon、人工地震)的多遇烈度以及人工地震的罕遇烈度下,层间位移角均满足我国现行抗震规范要求。该体系在高烈度区也可具有良好的抗震性能。     

耗能梁段腹板厚度对高强钢组合Y型偏心支撑框架受力性能的影响研究

为了研究耗能梁段腹板厚度对高强钢组合单层单跨Y型偏心支撑框架的受力性能,采用有限元软件ABAQUS分别对5个不同耗能梁段腹板厚度的高强钢组合单层单跨Y型偏心支撑框架模型进行了分析。结果表明:这种结构形式具有良好的耗能性能,耗能梁段能够充分发挥耗能的作用;耗能梁段腹板厚度对其强度、刚度和耗能性能均有较大影响,耗能梁段腹板厚度设计合理时,可满足结构在小震或中震作用下的承载力和变形要求,在大震下有良好的变形能力和耗散地震能量的能力。     

高强钢组合K形偏心支撑框架抗震性能对比分析

为研究不同强度组合的高强钢组合K形偏心支撑框架结构的抗震性能,设计了一组不同强度(Q345、Q460、Q690钢材)组合的5层K形偏心支撑框架结构算例Q345-5、Q460-5和算例Q690-5,选取10条地震动记录对其进行动力时程分析,得到各算例在不同水准地震作用下的耗能梁段转角和层间位移角。研究表明:8度罕遇地震作用下,高强钢组合K形偏心支撑框架的层间位移角比传统K形偏心支撑钢框架大,各算例耗能梁段全部进入塑性变形阶段;塑性层间位移角到达规范限值时,算例Q460-5框架梁开始进入塑性变形阶段,算例Q690-5框架柱、框架梁和支撑均处于弹性变形阶段,还可以承受更大的地震作用;达到定义的极限状态时,与传统偏心支撑钢框架相比,算例Q460-5能够承受的地震作用和耗能梁段转角更小;算例Q690-5承受的地震作用和耗能梁段转角更大。     

三层足尺分层装配支撑钢框架结构的振动台试验研究

为探究分层装配支撑钢框架体系在真实地震动力作用下的响应与性能,以某3层足尺房屋钢框架结构为研究对象,输入不同水准下的3条地震波进行振动台试验,分析了结构动力分步损伤行为、主（余）震层间变形、残余位移响应及其柔性支撑的可修复性。研究结果表明,结构满足我国规范对于抗震安全性的要求。在罕遇地震作用下,结构损伤集中于柔性支撑而主框架基本保持弹性,表现出损伤控制的特征,且震后基本无残余位移。未对支撑进行修复的结构在余震作用下的位移响应有所放大,但对支撑进行简易修复之后,结构抗震性能基本完全恢复。在超大地震作用下,主框架作为第二道抗震防线发展局部塑性变形,但震后残余位移仍然很小。柔性支撑初始是否张紧对结构初始刚度和层间位移分布有较大影响。支撑在动力作用下的突然张紧对结构产生了冲击效应,而支撑的延性可有效缓解此效应的影响。研究总体表明分层装配支撑钢框架体系应用于低多层建筑时具有优良的抗震性能与震后可恢复性。     

Seismic performance of floor-by-floor assembled steel braced structures with stiffened connections

This paper presents an overview of a full-scale testing on a tension-only concentrically braced beam-through frame (TCBBF). The implementation of TCBBF facilitates the construction of low-rise industrialised residential steel houses by means of floor-by-floor assembling. This type of TCBBF system features cold-formed hollow structural section columns connected to H-section through beams by end plate with bearing-type high-strength bolts. A two-storey, four-span by one-span TCBBF subjected to vertical loads was cyclically loaded horizontally to examine the seismic behaviour. Stable behaviour was observed up to a storey drift angle of 1/10. The cyclic behaviour was characterised by a linear response, a slip range and a significant hardening response. Deteriorating pinched hysteretic behaviour was notable for cyclic loading primarily because of cyclic brace compression buckling and tension yielding. TCBBF incorporates very slender bracing members that are unable to bear much axial load when subjected to compression. Alternating brace compression buckling and tension yielding induce unrecoverable plastic deformation, which results in a sharp decrease in the lateral system stiffness of TCBBF when lateral displacement becomes zero or around zero. Additionally, bracing members and frame members share different proportions of horizontal force although the dual systems bear the lateral forces collaboratively. The variation philosophy of distribution proportion of bracing and frame members is evaluated. Pushover analysis is undertaken to duplicate the test results and develop an analytical model, which is able to predict the elastic stiffness and the strength reasonably.