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V e和按照小震设计的基底剪力V d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。     

基于增量动力分析的梁贯通式支撑钢框架地震易损性研究

为了得到梁贯通式支撑钢框架节点刚度及承载力设计方法,基于增量动力分析(IDA)方法,研究了节点性能对多层梁贯通式支撑钢框架地震易损性的影响,得到了不同节点刚度和承载力设置下四种模型(刚接、全强度半刚接、半强度半刚接和铰接模型)的易损性曲线,定量评价了各模型超越各极限状态的概率和倒塌储备系数.研究结果表明:无论节点刚度和...     

多层钢框架结构强度折减系数研究

结构强度折减系数是基于强度抗震设计法中确定设计地震作用的关键。我国现行《建筑抗震设计规范》[1](GB 50011—2010,简称《规范》)对不同的结构体系采用单一的强度折减系数,不尽合理。在已有强度折减系数方法基础上,提出了以中震位移限值为极限位移的改进间接确定强度折减系数方法,将其应用于钢框架结构强度折减系数中,并与直接强度折减系数方法进行对比分析,验证了此方法的有效性和准确性,研究表明钢框架结构强度折减系数不受建筑层数的影响,其强度折减系数接近于4。     

人字形偏心支撑钢框架的结构影响系数

采用弹塑性增量动力分析法,利用ANSYS有限元软件分析了9个人字形偏心支撑钢框架结构算例,得到人字形偏心支撑钢框架的结构影响系数R、超强系数RΩ、延性折减系数Rμ,给出了R的建议值。     

人字形中心支撑钢框架的结构影响系数研究

阐述了结构影响系数的定义及计算方法,采用典型的地震动记录对按照我国规范要求设计的一人字形中心支撑钢框架结构进行增量动力分析并得到其结构影响系数。结果表明,结构影响系数受分析方法、极限状态及破坏准则、有限元模型等影响较大,需要在这些方面作大量的研究工作。     

高层建筑偏心支撑钢框架减轻地震响应分析

本文首先分析了偏心支撑钢框架中的关键构件－耗能连梁的弹塑性性能,提出了一种简化的屈服模型,并在此基础上编制一种新型的弹塑性时程分析程序。利用所编制的程序对两个典型算例进行了弹塑性时程分析,并对算例中偏心支撑框架和中心支撑框架两种结构的地震响应进行了比较。其结果表明,偏心支撑框架结构的地震响应要明显小于中心支撑框架结构的地震响应。     

支撑长细比对人字形中心支撑钢框架结构影响系数的影响

为考察支撑长细比对中心支撑钢框架结构影响系数的影响,设计支撑长细比不同的4个人字形中心支撑钢框架并通过增量动力分析计算其结构影响系数。结果表明,对于按照我国规范设计的普通中心支撑钢框架,随着支撑长细比的增加,结构影响系数R逐渐减小;而对于欧美规范中的特殊中心支撑钢框架则并非如此。     

Y型偏心支撑钢框架倒塌储备能力分析

为了评估Y型偏心支撑钢框架结构的倒塌储备能力,提出了一种针对于Y型偏心支撑钢框架结构的倒塌判定标准,并利用这个标准对不同设防烈度和不同层数的4个算例进行了IDA分析,得到了4个算例的倒塌储备系数和倒塌概率曲线.分析结果表明：相同条件按9度设计的Y型偏心支撑结构比按8度（0.2g）设计的结构倒塌储备能力弱,且层数越高其倒塌储备能力越弱.     

偏心支撑钢框架延性抗震设计探讨

偏心支撑钢框架结构体系是一种非常适合强震地区的抗震结构体系.国内外许多高层建筑采用了该结构体系,尤其在美国与日本的高地震烈度地区.国内外现行规范对该体系的设计均未能充分体现其良好的延性与耗能能力,但只有通过结构的延性设计才能使结构真正具有耗能能力.本文从不同支撑类型的刚度、高跨比、延性和双重体系探讨了支撑类型的选择与布置形式,分析了耗能梁长度与截面设计以及耗能梁与支撑、柱的连接形式对偏心支撑钢框架结构体系延性和耗能能力的影响,提出了偏心支撑钢框架结构体系延性抗震设计的建议与思路,为规范修订和工程应用提供一些参考.     

铰接中心支撑钢框架体系结构设计研究

在进行结构体系比较和振动台试验验证的基础上,确定了某大型电厂主厂房选用铰接中心支撑钢框架体系。对深化设计方案进行了地震响应的数值模拟研究。虽结构平面扭转和竖向质量分布均不规则,但考虑到多遇地震下没有构件屈服或失稳,且多遇、罕遇地震下的层间侧移角均满足规范要求,认为结构设计较为合理,可以满足"小震不坏"、"大震不倒"的抗震设防要求。同时也再次验证了只要设计合理,铰接中心支撑钢框架体系在8度抗震设防区仍可具有较好的抗震性能,高度也可以突破民用建筑12层的限制。最后给出了铰接中心支撑钢框架结构节点连接部分抗震设计的一些原则性建议。     

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。     

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.     

框架-支撑钢结构抗震性能的有限元分析

近年来,我国的大中城市相继出现了大批的中高层钢结构建筑。框架一支撑结构体系作为中高层的一种结构形式被广泛采用。本文运用大型通用有限元软件ANSYS,采用三维建模,对-9层框架-支撑钢结构建筑进行了抗震性能的计算分析,分析包括模态分析、反应谱分析、弹性刀单塑性时程分析,分析结构在地震作用下的横向变形和支撑随地震波的内力响应情况等。研究成果可以为类似工程提供借鉴。     

Seismic testing and numerical analysis of Y‐shaped eccentrically braced frame made of high‐strength steel

In eccentrically braced frame made of high‐strength steel (HSS‐EBF), link and brace are made from conventional steel whereas other structural members use high‐strength steel. Using HSS for beams and columns in EBF can reduce steel consumption and increase economic efficiency. In this paper, one shake table test of a 1:2 scaled three‐story Y‐shaped HSS‐EBF (Y‐HSS‐EBF) specimen was carried out to study its seismic behavior underground motions with different peak ground accelerations. The dynamic properties, base shear force, displacement, and strain responses of the specimen were obtained from this test. In addition, the finite element models of two 10‐story Y‐HSS‐EBF buildings and one 10‐story conventional Y‐EBF building were evaluated for seismic effects. Nonlinear pushover and dynamic analyses were conducted to compare their seismic performance and economy. The results indicated that the specimen exhibited sufficient lateral stiffness and safety but suffered some localized damages. During the high seismic intensity earthquakes, the links of the test specimen were in inelastic to dissipate the earthquake energy, whereas other structural members remained in the elastic state. Under the same design conditions, Y‐HSS‐EBF used less steel than that of conventional Y‐EBF, which could reduce the amount of steel used in Y‐HSS‐EBF. The Y‐HSS‐EBF is a safe, dual system with reliable seismic performance.     

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.     

带支撑钢框架非线性稳定分析

通过运用有限元软件ANSYS,建立了三维空间分析模型,对带支撑钢框架在考虑混凝土楼板作用下进行非线性稳定分析,运用ANSYS提供的稳定分析方法得出了钢框架体系梁、板、柱相对刚度对屈曲荷载的影响。     

Fundamental periods of steel eccentrically braced frames

This paper describes formulation of a hand method that can be used to estimate the computed fundamental periods of vibration of building structures in general and steel eccentrically braced frames (EBFs) in particular. The developed method uses the Rayleigh's method as a basis and utilizes the roof drift ratio (RD_R) under seismic forces as a parameter. To obtain RD_R, more than 4000 EBFs were designed by considering the seismic hazard, number of stories, braced bay width and link length to bay width ratio as prime variables. A model was developed to estimate RD_R, which depends on the rigid plastic deformation mechanism for a typical EBF. The method was verified using design data produced as a part of this work as well as data published in literature. The verifications indicate that the proposed formulation is capable of providing acceptable estimates of the computed period. When compared with existing empirical period–height relationships, the proposed formulation offers closer estimates with reduced scatter. The method was further refined to derive new period–height relationships for two different seismicity regions. The accuracy of the relationship for high seismic regions was verified using measured periods of EBF buildings. Copyright © 2014 John Wiley & Sons, Ltd.     

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。     

防屈曲支撑钢框架结构中被撑柱抗震设计探讨

通过3个算例,对采用人字形和V字形的无粘结内藏钢板支撑剪力墙(即人字形和V字形防屈曲支撑)的防屈曲支撑钢框架结构的抗震性能进行分析。重点考察大震下,支撑的轴力分布和对被撑柱所受轴力的影响。分析表明,采用结构在一阶振型下的支撑轴力分布来设计被撑柱的做法,适用于多层的防屈曲支撑钢框架结构;而对于高层的防屈曲支撑钢框架结构,高振型影响较显著,上述设计方法对被撑柱的设计较保守,有必要考虑高振型参与下的支撑轴力分布来设计被撑柱。