开洞波形钢板剪力墙受剪承载力及耗能能力分析

为明确波形钢板剪力墙不发生屈曲的界限条件并分析开洞对其承载力及耗能能力的影响,基于波形钢板剪切屈曲理论推导其屈曲应力计算式,并采用数值分析及变形等级划分方法得到约束刚度比取值范围,由此提出波形钢板剪力墙不发生屈曲的界限条件为屈曲应力大于剪切屈服应力且约束刚度比大于3。通过对比开洞模型的变形等级计算参数,验证界限条件对开洞波形钢板墙的适用性,建立有限元模型研究钢板墙高宽比、钢板厚度、开洞率、洞口高宽比及洞口位置对波形钢板墙承载力及耗能能力的影响。结果表明：钢板高宽比越小、板厚越大,开洞对其承载力及耗能能力的削弱程度越大,洞口高宽比在0.33~0.5之间时开洞波形钢板墙的承载力及耗能最大,中心开洞时的最小。基于波形钢板剪力墙全截面剪切屈服的受力机理对其受剪承载力和塑性耗能计算式进行推导,并通过拟合得到考虑洞口参数影响的开洞波形钢板剪力墙受剪承载力及耗能折减系数计算式;通过9组不开洞模型和30组不同洞口尺寸及位置的开洞模型对计算式的有效性进行验证。结果表明计算值与模拟值的误差均在15%以内,适用于满足无屈曲界限条件的开洞波形钢板剪力墙。     

单面外包混凝土组合钢板剪力墙的混凝土板厚需求

外包混凝土组合钢板剪力墙抗剪承载力高、抗侧刚度大、耗能能力强,是一种有效的高层结构抗侧力构件。该构件利用钢筋混凝土板对钢板提供的侧向约束,使得钢墙板屈曲晚于剪切屈服。延性设计要求钢板进入剪切屈服后要有一定的变形耗能能力,混凝土板需达到一定的厚度才能保证钢板发生弹塑性屈曲。因此混凝土板厚需求是组合钢板剪力墙设计中的一个关键问题,但前人对于这方面的研究并不是很多。考虑栓钉间距、混凝土板厚度、钢板厚度、混凝土强度等级、墙板高宽比的变化对单面外包混凝土组合钢板剪力墙进行了弹塑性分析。基于有限元计算结果,提出了单面外包混凝土组合钢板剪力墙在层间侧移角小于0.4%时钢板不发生屈曲的混凝土板厚需求计算公式。     

钢板剪力墙的非完全拉力场

经典拉力场理论忽略了剪切场部分的影响，仅对板无限薄的理想情况计算结果是准确的；而对有厚度的实际受剪板，采用该理论计算会普遍低估受剪板的弹性刚度和承载力并高估屈服位移，板越厚则误差越大。为此，建立了非完全拉力场理论以准确描述受剪板的屈曲后应力状态，并基于该理论得到了适用于任意厚度受剪板和防屈曲板的弹性刚度、承载力和屈服位移的计算式，具有很高的计算精度。与壳单元精细模型分析结果相比，计算所得弹性刚度的误差不大于2.8%,承载力的误差不大于2.6%。根据屈曲后压应力对弹性刚度和承载力影响程度的不同，将受剪板分为厚板(λ≤1,λ为高厚比)、中厚板(1<λ<3)和薄板(λ≥3)三类，同时定量明确了经典拉力场理论对三类板的误差并给出了建议的适用范围。基于非完全拉力场理论推导了受剪板屈曲后的应力场方程，并提出了改进的通用拉杆模型。参数分析表明：对任意厚度的钢板剪力墙和防屈曲钢板剪力墙，该模型与壳单元精细模型相比，计算弹性刚度误差不大于5.5%,承载力误差不大于2.8%。     

竖向加劲钢板剪力墙试验研究

为研究加劲肋和竖向荷载对钢板剪力墙受力性能的影响,分别对1榀和2榀竖向加劲钢板剪力墙进行推覆和往复试验,其中往复试验中以有限竖向荷载为控制变量。通过考察剪力墙板变形性能以及竖向加劲肋的整体屈曲及局部屈曲,得到试件的推覆曲线和荷载-位移滞回曲线,并基于试验结果分析试件承载力、抗侧刚度和耗能能力等力学性能。结果表明:有限竖向荷载对竖向加劲钢板剪力墙的屈曲荷载、抗侧刚度和耗能性能影响较大,对屈服荷载和极限承载力影响较小;并给出了竖向加劲肋和侧边加劲肋的门槛刚度系数值。     

改进型组合钢板剪力墙有限元分析与研究

为改进型组合钢板剪力墙设计了合理的有限元模型,对纯钢板和3种不同混凝土板厚度以及3种跨高比的组合墙进行了有限元对比模拟分析.结果表明：两侧混凝土板对组合墙的承载力影响不大但可提高其后期刚度,并可有效限制钢板的出平面屈曲;同时,随着跨高比的增大,结构整体承载力有所提高.在此基础上,比较了几组模型的抗剪承载力性能,以及预制墙板对其屈曲荷载的影响,并给予建议的简化模型.可以看出,改进型组合钢板剪力墙有较好的延性以及耗能性能,能充分利用材料的性能.     

三类钢板剪力墙结构试验研究

防屈曲钢板剪力墙已被试验证明是优秀的抗侧耗能构件,但墙板嵌入受弯框架时,二者之间的相互作用尚需进一步研究。为此进行了两层单跨钢框架内嵌防屈曲钢板剪力墙的试验研究,作为比较同时进行了两层单跨钢框架内嵌非加劲钢板剪力墙与两层单跨钢框架内嵌组合钢板剪力墙结构的试验研究。在试验的基础上,对试件进行有限元分析,比较了三类钢板剪力墙之间的性能差异。研究表明,防屈曲钢板剪力墙能够消除无加劲钢板剪力墙在水平荷载下产生的巨大屈曲噪声,具有较大的初始刚度与承载力,拥有良好的延性与滞回耗能性能,而且由于其屈服先于屈曲发生,对周边框架产生的附加弯矩很小;组合钢板剪力墙的性能与防屈曲钢板剪力墙相似,但由于后期外包的混凝土发生脱离,内嵌钢板剪力墙会产生拉力带,不仅对框架产生不利影响,而且自身承载力、刚度与耗能能力均有不同程度的退化。图32表1参12     

密肋网格防屈曲钢板剪力墙结构性能试验研究

为了研究密肋网格防屈曲构件对钢板剪力墙结构性能的影响,对设置防屈曲构件和不设置防屈曲构件的两榀三层钢板剪力墙结构进行了拟静力试验研究。对比分析两种结构的滞回性能,破坏模式,以及承载力、耗能和刚度等力学性能指标。研究表明：在不考虑肋条对内填板嵌固的基础上,需对密肋网格防屈曲钢板剪力墙肋板间距以及肋板刚度进行构造设计;相比于不设置防屈曲构件的钢板剪力墙,密肋网格防屈曲钢板剪力墙结构,避免了结构滞回环体的捏缩现象和墙板的整体呼吸效应,极大减弱了墙板的声响和震颤现象,降低了边框柱的破坏程度;墙板破坏为小区格内板件和边缘板件的局部屈曲,肋板未发生破坏;设置防屈曲构件结构的承载力和耗能量分别提高24%和20%,位移延性系数降低28%。     

改进钢板-混凝土组合剪力墙结构受力性能分析

钢板-混凝土组合剪力墙由钢框架、内嵌钢板及一侧通过螺栓与之连接的混凝土板组成,其中传统组合剪力墙中混凝土板四边与钢框架直接接触,而改进组合剪力墙中二者之间有一定间距,以避免其在结构侧移较小时发生接触。采用ABAQUS有限元软件分别建立了组合剪力墙的精细有限元模型,研究了其受力性能以及板框相互作用全过程,分析了钢板高厚比对组合剪力墙整体承载力、抗侧刚度以及板框剪力分配等的影响。研究表明:组合剪力墙中混凝土板有效抑制钢板弹性屈曲,钢板主要以剪切屈服承载,对框架柱的附加弯矩较钢板剪力墙明显降低;相比钢板剪力墙,传统组合剪力墙承载力提高25%,抗侧刚度提高10%,混凝土板承载近30%;改进组合剪力墙承载力提高10%,抗侧刚度提高5%,混凝土板基本不承担剪力;随着钢板高厚比的减小,组合剪力墙的承载力与抗侧刚度提高,但两类组合剪力墙之间的差别变小;钢板承载比例不断增大,当钢板过厚时需要防止底层框架过早屈服。     

钢板剪力墙抗震性能试验研究

以天津国际金融会议酒店工程为背景对钢板剪力墙的抗震性能进行试验研究。完成了3个4层1∶5缩尺比例的钢板剪力墙试件的拟静力试验。试件主要变化参数包括墙板开洞和中柱设置。试件SPSW-1墙板开洞,试件SPSW-2墙板不开洞,试件SPSW-3带有中柱,且中柱一侧墙板开洞。在钢板剪力墙的墙板上布置了槽形和一字形两种截面形式的加劲肋。试验结果表明：钢板剪力墙结构具有良好的承载力、延性和耗能能力;开洞降低了钢板剪力墙结构的刚度和承载力;中柱提高了钢板剪力墙结构的刚度和承载力;加劲肋可增强钢板剪力墙结构的刚度和稳定承载力,开洞补强效应显著。     

带约束拉杆双层钢板内填混凝土组合剪力墙抗震性能试验研究

提出一种带约束拉杆双层钢板内填混凝土组合剪力墙,通过对6个剪跨比为2.0、轴压比为0.6的此类剪力墙试件的低周往复加载试验,研究试件的破坏形态、滞回曲线、骨架曲线、承载力退化、刚度退化、位移延性系数和耗能等抗震性能。结果表明：带约束拉杆双层钢板内填混凝土组合剪力墙抗震性能良好,6个试件的屈服位移角平均值为1/147,极限位移角平均值为1/48,位移延性系数平均值为3.57;减小约束拉杆间距和采用梅花式布置约束拉杆的方式,能更好地对钢板和混凝土提供约束,延缓钢板局部屈曲,增大混凝土的极限变形能力,提高剪力墙承载力、延性和耗能能力,减缓承载力退化和刚度退化,改善剪力墙抗震性能。     

Shear‐displacement diagram of steel plate shear walls with precompression from adjacent frame columns

An analytical model of the unstiffened steel plate shear wall (SPSW) considering precompression from the adjacent frame columns is proposed and experimentally verified. First, the distribution and transferring of the gravity loads between boundary columns and the infill steel plate was proposed. Second, the shear‐displacement diagram of the SPSW under compression–shear interaction was obtained, and to further consider the global bending deformation, the shear‐displacement diagram of the SPSW under compression–shear–bending interaction was obtained. Third, the load‐carrying capacities and deformations at the state of elastic buckling of the infill steel plate, the yield of Zones I and III, the yield of Zone II, and the yield of the boundary frame were presented. Finally, cyclic loading test on four scaled one story single bay unstiffened SPSWs under different axial forces at the top of the columns was carried out to verify the proposed analytical model. Shear‐displacement relationship, shear capacity, and envelope curves of the specimens were compared with the predicted values. Results indicate that the proposed analytical model can reasonably predict the decrease of the shear load capacity and stiffness of the SPSWs due to the existence of the axial load at the boundary columns.     

Stress state of steel plate shear walls under compression–shear combination load

This paper investigates the stress state of the infill steel plate for the unstiffened steel plate shear walls (SPSWs) under compression–shear combination load. First, the infill steel plate is divided into three zones, the stress state of each zone under compression is derived, and the accuracy of the analytical model is verified by a series of numerical examples. Second, considering the combination effects of the gravity load and shear force from the adjacent boundary columns, the stress state of each zone is proposed and discussed. Then the shear capacity of the infill steel plate for the unstiffened SPSWs with gravity load acting on the top of the boundary columns is proposed. Finally, the shear capacity of 21 numerical SPSW specimens with various axial stresses of the boundary columns and different steel infill plate thicknesses is predicted.     

Seismic behavior of code designed steel plate shear walls

The AISC Seismic Design Provisions now include capacity design requirements for steel plate shear walls, which consist of thin web plates that infill frames of steel beams, denoted horizontal boundary elements (HBEs), and columns, denoted vertical boundary elements (VBEs). The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action, providing ductility and energy dissipation through tension yielding of the web plate. HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates. VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs.This paper assesses the behavior of code designed SPSWs. A series of walls are designed and their behavior is evaluated using nonlinear response history analysis for ground motions representing different hazard levels. It is found that designs meeting current code requirements satisfy maximum interstory drift requirements considering design level earthquakes and have maximum interstory drifts of less than 5% for maximum considered earthquakes. Web plate ductility demands are found to be significantly larger for low rise walls than for high rise walls where higher modes of vibrations impact the response. The percentage of story shear resisted by the web plate relative to the boundary frame is found to be between 60% and 80% and is relatively independent of panel aspect ratio, wall height, or hazard level, but is affected by transitions in plate thickness. Maximum demands in VBEs in design level shaking are found to be considerably less than those found from capacity design for SPSWs with 9 or more stories.     

方钢管混凝土框架-十字加劲薄钢板剪力墙抗震性能试验研究

对3个单跨两层1∶3比例的方钢管混凝土框架-薄钢板剪力墙试件进行了低周反复荷载试验,研究了十字加劲薄钢板剪力墙的抗震性能,并与方钢管混凝土框架-非加劲薄钢板剪力墙比较。对比了框架梁柱内隔板式节点与穿芯高强螺栓-端板节点对结构性能的影响。得到了方钢管混凝土框架-薄钢板剪力墙的破坏形态、荷载-位移滞回曲线、骨架曲线、特征荷载和位移及抗震性能指标等,分析了结构的破坏特征、延性、耗能能力、承载能力及刚度退化等力学性能。结果表明,方钢管混凝土框架-薄钢板剪力墙具有良好的抗震性能;十字加劲肋限制了薄钢板剪力墙的面外变形,提高了其承载力与耗能能力,但对整体刚度影响较小;穿芯高强螺栓-端板节点提高了结构的承载力与刚度。     

斜向槽钢加劲钢板剪力墙弹性剪切屈曲研究

通过对剪切作用下的闭口斜加劲钢板剪力墙进行有限元弹性屈曲分析,研究了肋板刚度比和抗扭抗弯刚度比对斜向槽钢加劲钢板剪力墙剪切屈曲性能及其加劲门槛刚度的影响。通过有限元分析,得到了斜向加劲钢板剪力墙临界剪切屈曲应力随内填板跨高比和加劲肋抗扭抗弯刚度比变化的关系曲线。考虑加劲肋对内填板加劲边转动约束,提出了第二门槛刚度,并给出了具有良好精度的斜向槽钢加劲钢板剪力墙的门槛刚度及第二门槛刚度计算公式。研究结果表明,受压型加劲肋对加劲板的临界剪切屈曲应力提高明显,随肋板刚度比的增大,加劲板的剪切屈曲应力增大,而受拉型加劲肋对板的屈曲荷载提高有限;当肋板刚度比达到第二门槛刚度时,加劲肋可以完全约束加劲边的面外位移和转动。当提高加劲肋的抗扭抗弯刚度比时,能够有效降低加劲肋的门槛刚度,因此,建议加劲肋的抗扭抗弯刚度比不低于0.307。     

Sub-structural pseudo-dynamic performance of two full-scale two-story steel plate shear walls

This paper describes two eight-meter tall and four-meter wide, two-story steel plate shear walls (SPSWs) that were fabricated and tested using sub-structural pseudo-dynamic testing procedures in the National Center for Research on Earthquake Engineering (NCREE). In the Phase I tests, all wall panels were restrained using horizontal tube restrainers on both sides in order to minimize both the out-of-plane displacement and the buckling sound. In the Phase II tests, damaged steel plates were removed and replaced with new plates without restrainers. Both specimens were tested under pseudo-dynamic loads using several scaled ground accelerations. This paper presents primarily the design of the specimen, experimental results, and simplified analytical modeling techniques for Phase I specimen. Results of the Phase I tests show that (1) the SPSW specimen sustained three earthquakes without significant wall fracture or overall strength degradation, (2) the horizontal restrainers were effective in improving the serviceability of the SPSW, (3) the responses of the SPSW can be satisfactorily predicted using the strip model and the tension-only material property implemented in the PISA3D computer program, (4) the energy-dissipating capacity of the SPSW specimen was found to be substantially reduced when it was subjected to the same ground motions again, and (5) if the boundary elements are properly proportioned using the capacity design principle, the equivalent brace model is effective for the response analysis of SPSW buildings subjected to strong ground motions.     

Behavior of steel plate shear walls with pre-compression from adjacent frame columns

This paper investigates the behavior of steel plate shear walls (SPSWs) with pre-compression from adjacent frame columns which is produced in the construction process. Firstly, some parameters used in analytical finite element models, such as the stiffness of frame beams and columns and the magnitude of the loads are discussed. Then, numbers of numerical examples are analyzed and show that the influence of pre-compression varies with the dimension of SPSWs. Also, the distribution and transferring of axial forces between frame columns and SPSWs during loading are discussed. Finally, a reduction coefficient of shear-carrying capacity of SPSW due to pre-compression is proposed.     

半刚性框架-屈曲约束钢板剪力墙结构弹塑性层剪力分布研究

为研究弹塑性状态下半刚性框架-屈曲约束钢板剪力墙结构(BR-SPSW)的层剪力分布,设计了具有理想屈服模式的5层、10层、15层和20层的BR-SPSW结构等效拉杆简化模型。综合考虑结构层数、构件截面、近场地震速度脉冲效应及远场地震加速度循环累积效应对结构的影响,采用弹塑性时程分析方法获得了BR-SPSW结构在两类地震作用下的层剪力分布平均值,提出了BR-SPSW结构弹塑性状态的层剪力分布模式,并基于已有层剪力分布模式及GB 50011—2010《建筑抗震设计规范》的底部剪力法提出的层剪力分布模式进行对比。结果表明,近场地震波的速度脉冲效应和远场地震波的加速度循环效应对半刚性框架 屈曲约束钢板墙的层剪力分布影响较大,层剪力分布应综合考虑二者的影响。建议的层剪力分布模式在计算精度上优于其他层剪力分布模式,可为屈曲约束钢板墙结构基于性能的设计方法提供参考。     

Effect of column stiffness on drift concentration in steel plate shear walls

Steel plate shear walls (SPSWs) are a lateral force resisting system consisting of thin infill steel plates surrounded by boundary frame members. Hysteretic energy dissipation and lateral force resistance of the system are primarily achieved through the yielding of the infill steel plates. However, during an earthquake event, the infill plates at different building stories may not yield simultaneously due to many factors such as overstrength of some infill plates and the actual lateral force distribution which is different from the one assumed in design, possibly resulting in inter-story drift concentrations in the system. This paper investigates the effect of column stiffness on mitigating drift concentration in SPSWs. Based on an example two-story SPSW, mathematical models are derived to characterize the system behavior and quantify the effect of column stiffness on the mitigation of drift concentration. Nonlinear static pushover analyses using finite element models are performed to further validate the developed models. Finally, based on the developed models, parametric analyses are conducted to investigate the effect of column stiffness over a practical range of the considered parameters, followed by a discussion of the minimum SPSW column stiffness specified in North American codes. The results from this investigation show that column stiffness should be a design parameter to ensure a reasonably uniform drift distribution and hence a more uniform infill plate yielding along the height of SPSW buildings.