Influence of crack on the steel plate shear walls strengthened by diagonal stiffeners

In spite of existing comprehensive studies on the behavior of steel plate shear wall (SPSW), some aspects of the SPSW have remained unknown, yet. One of the important aspects that is unknown is the crack effect on the SPSW behavior in linear and nonlinear zones. Some experimental studies have been reported that SPSWs were fractured due to crack propagation. Therefore, the crack effect on the behavior of SPSW should be accounted in considering of SPSW behavior. Although the effect of crack on the thin SPSW has been investigated to a limited extent numerically, stiffened SPSPW, especially diagonally stiffened SPSW, has not been studied. In doing so, in this paper, the effect of crack effect on the behavior of diagonally stiffened SPSWs is studied parametrically and numerically. Numerical results showed that stiffened walls exhibit better behavior in the presence of crack compared with SPSW in both elastic and inelastic zones. Because crack propagates in nonlinear zone, it has not effective on elastic behavior of diagonally stiffened SPSW. The effect of crack was also presented as mathematical equations to estimate load–displacement curve that are in agreement with the finite element results especially for wall thinker stiffeners.     

Performance-based plastic design of steel plate shear walls

The existing codes and design guidelines for steel plate shear walls (SPSWs) fail to utilise the excellent ductility capacity of SPSW systems to its fullest extent, because these methods do not consider the inelastic displacement demand or ductility demand as their design objective. A performance-based plastic design method for SPSW systems with rigid beam-to-column connections is proposed in this work, which sets a specific ductility demand and a preferred yield mechanism as its performance targets. The effectiveness of the proposed method in achieving these targets is illustrated through sample case studies of four- and eight-storey SPSW systems for varied design scenarios. A comparison with the existing AISC method for the same design scenario shows that the proposed method consistently performs better, in achieving these performance-based targets. The proposed method is modified to account for P-Delta effects, wherever necessary. This modified method is found to be more effective than the original proposal, whenever P-Delta effects are significant.     

自复位钢框架钢板剪力墙性能化设计方法

基于“自复位”理念,提出了一种采用钢板剪力墙耗能的自复位钢框架钢板剪力墙结构,对其进行了受力机理分析,并给出了自复位钢框架钢板剪力墙的复位条件。依据GB 50011—2010《建筑抗震设计规范》设定了自复位钢框架钢板剪力墙基于性能的设计目标,基于性能目标提出了自复位钢框架钢板剪力墙的设计流程,从构件的实际受力状态出发对该设计方法进行了研究,并推导出构件的设计公式。以某传统钢框架为例,对其进行了由钢板剪力墙耗能的自复位结构边缘构件设计,并采用有限元软件ABAQUS对其中单榀单跨进行了Pushover分析。结果表明：当层间位移角达到2%时,结构的残余变形量控制在0.2%以内,主体结构边缘构件仍处于弹性工作状态,推覆过程中钢板墙耗散了大量能量;推覆结束后,结构余留少量残余变形,这主要是由于梁柱节点绕梁上下翼缘转动时梁上下翼缘角部受到挤压引起,可通过适当设置翼缘加强板减少甚至消除残余变形。     

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。     

Optimized design procedure for coupling panels in steel plate shear walls

Coupling beams have had a widespread application as performance enhancing devices within concrete structures and more recently also in steel structures. However, the conventional coupling beams are not so efficient in coupling distant walls. In this paper, a novel form of coupling members, namely, coupling panels is proposed and, then, the application for a nine‐story building is investigated. Coupling panels are steel plates which are exerted in the intermediate spans between adjacent shear walls and act as a mega‐coupling beam. First, a verified finite element model is constructed to demonstrate coupling panel behavior along with its global structural mechanism. Subsequently, a nine story building is designed and retrofitted as a new and existing building, using coupling panels. Moreover, an innovative optimization algorithm is proposed in order to achieve the best plate configuration to improve the structural performance using Nonlinear Static Analysis, Modal Pushover Analysis and Time History Analysis and the corresponding results are compared. In summary, it is shown that coupling panels can considerably control structural deformation demands toward a uniform pattern and reduce demands of main shear walls. The optimized design method also leads to a more economical design in comparison with force‐based design approaches. In addition, the proposed coupling panels are shown to be significantly effective, regarding to energy dissipation during earthquakes, and can enhance the structural resiliency. Copyright © 2016 John Wiley & Sons, Ltd.     

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。     

任意厚度非加劲钢板剪力墙与防屈曲钢板剪力墙的通用拉杆模型

钢板剪力墙在墙板屈曲后仍具有一定的抗压能力,板厚越大,抗压能力越强,对结构整体性能的影响也越大,现有的简化模型尚不能很好地考虑该效应.为此,首先分析了计入压应力的钢板墙的受力状态,进而推导了考虑墙板抗压能力的钢板剪力墙的刚度、承载力和屈服位移的计算式,并据此提出了一种通用拉杆模型.该模型仅通过调整经典多拉杆模型中拉杆的...     

钢板剪力墙低周反复荷载试验研究

本文进行了6个13比例钢板剪力墙的低周反复荷载试验,重点研究了钢板墙极限承载力和滞回性能,为钢板墙结构利用屈曲后强度及抗震设计提供试验依据;本试验揭示了边柱局部屈曲、加劲肋布置形式、加劲板刚度和板高厚比对钢板墙滞回性能的影响。试验结果表明,边柱不出现局部屈曲是钢板墙发挥极限承载力的重要保证;厚板和较强的加劲肋对提高钢板墙滞回曲线的饱满度和滞回环面积是有利的;三种钢板墙以交叉加劲板的承载力和滞回性能最佳,十字加劲板次之,钢板墙结构耗能能力依赖于钢板与边柱的弹塑性变形和钢板面外鼓曲变形。试验曲线与应用弹塑性大挠度有限元法计算的滞回曲线吻合良好;利用屈曲后强度的钢板墙受剪承载力,其试验值与本课题建议公式及有限元值计算结果基本一致。     

Experimental and theoretical studies of steel shear walls with and without stiffeners

Steel plate shear walls are lateral load resisting systems, especially against earthquake excitation. They are constructed with or without stiffeners. In contrary to stiffened steel plate shear walls, there are many theoretical and experimental studies on these systems without stiffeners and different analytical methods have been presented for them which are mostly applicable to very thin steel plates shear walls. In this research, two one story similar steel plate shear walls with and without stiffeners and one of their surrounding frames were tested and the behavior of them was studied. The results showed that, installation of stiffeners improved the behavior of the steel plate shear walls. It caused 26% increase in energy dissipation capacity and 51.1% increase in the shear stiffness of steel plate while its effect on the steel plate shear strength was minor. In addition, the Plate-Frame interaction theory (PFI) was verified by using the experimental results and the test results showed that, this theory has good capability for predicting the shear load – displacement curve behavior of steel shear walls with or without stiffeners.     

十字加劲钢板剪力墙的抗剪极限承载力

我国《高层民用建筑钢结构技术规程》规定了钢板墙剪切弹性屈曲不先于剪切屈服,其明显的不足是没有利用板的屈曲后强度,同时弹性屈曲也不能作为结构在弹塑性阶段的设计指标。本文应用板的大挠度弹塑性有限元方法对十字加劲方形钢板剪力墙的屈曲后性能和极限承载力进行了系统的研究,并在大量数值分析的基础上,提出了以板的平均剪切应变相应的剪应力作为钢板剪力墙承载能力的极限状态,以达到利用薄板屈曲后强度的目的,进而提出了钢板剪力墙承载力的设计简化计算公式及钢板墙侧柱刚度阈值的计算公式,供设计参考。数值计算结果表明,影响钢板墙抗剪性能主要有三个参数:板高厚比、肋板刚度比和边柱刚度。     

Characteristics of the wall-frame interaction in steel plate shear walls

The nonlinear response of steel plate shear wall (SPSW) dual systems under lateral loading with regard to the interaction between the infill plates and frame members is studied. A number of SPSWs are numerically analyzed and the results are utilized to discuss (a) the influence of infill plates on the behavior of frames and (b) to evaluate their degree of effectiveness in resisting lateral loads. Results show that SPSWs designed according to design codes should have desirable sequences of yielding and that plastic deformations should primarily be provided by the infill plates. It is illustrated that the infill plates are very effective in the initial stages of loading (up to the drift angle of 1% ) and absorb substantial part of storey shear. However, once diagonal yield zones develop in the infill plates, they begin to lose their effectiveness; and when yield zones spread throughout the wall, additional applied loads are essentially carried by the frame members.     

Hysteretic analysis of thin steel plate shear walls

Thin steel plate shear walls (TSPSWs) are especially concerned due to the economic factor and excellent energy dissipation capacity. TSPSWs commonly define as steel plate with height-to-thickness ratio over 300. The post-buckling capacity, deformability and energy dissipation capacity of TSPSWs are now accepted by structural engineers. This brings about evident economic benefit. This paper presents a finite element analysis of TSPSWs under cyclic loading. The calculated results are compared with experimental results to validate its accuracy. Then based on the finite element model, the influence of height-to-thickness ratio and span-to-height ratio on the hysteretic behavior of TSPSWs is analyzed. Also, the influence of column moment rigidity on the development of tension field is studied. At last, a new simplified Combined Strip Model is introduced which is suitable for the hysteretic analysis of TSPSWs. Based on the Combined Strip Model, a formula for calculating shear strength is proposed, which considers the compression effects of TSPSWs.     

钢板剪力墙钢板与框架相互作用分析

利用屈曲后性能的钢板剪力墙作为一种新型抗侧力构件,其边缘框架是保证钢板形成拉力带并充分发挥作用的基础,而形成拉力带的钢板又对边缘框架产生较大作用。通过对不同跨高比和厚度的钢板剪力墙进行静力推覆加载,分析钢板剪力墙受力全过程,研究在不同阶段钢板与框架之间的刚度、剪力分配规律和钢板与框架之间的相互影响。结果表明,可以按一定的位移控制来设计钢板剪力墙,使其按期望的失效路径破坏;在设防烈度下,通过控制结构层间位移角小于0.5%,可实现剪力墙仅钢板屈服耗能、而边缘框架仍处于弹性的屈服模式;在大震阶段,钢板剪力墙通过钢板耗散大部分能量,边缘框架辅助耗散部分能量。     

Estimating fundamental periods of steel plate shear walls

Seismic design codes generally specify empirical formulae to estimate the fundamental vibration periods of buildings. Currently, most building codes provide the same empirical formula to estimate the fundamental periods for steel plate shear walls and reinforced concrete shear walls. The work presented in this paper shows that the code formula predicts periods that are generally shorter than the periods obtained from a validated finite element analysis of a series of steel plate shear walls of different geometries. An improved simple formula for estimating the fundamental period of steel plate shear walls is developed by regression analysis of the period data obtained from analysis. In addition, the effectiveness of a simple shear-flexure cantilever formulation for determining fundamental periods and P-Δ effects of steel plate shear wall systems is presented. The effects of perforations in the infill plates and column base support conditions on fundamental periods are also explored.     

基于滞回耗能谱的钢板剪力墙结构性态设计方法

结构在地震作用下的损伤往往与地面运动的加速度循环特征密切相关,为反映这种地面运动特征,引入了累积延性比,并结合标准化的滞回耗能谱,提出了钢板剪力墙（SPSW）结构基于能量的性态抗震设计方法。该方法给出了SPSW结构中钢梁、钢柱、剪力墙板累积滞回耗能的计算方法,引入捏缩系数来反映构件的滞回特性,采用能力设计方法确定剪力墙板周边的梁、柱截面,确保SPSW结构在罕遇地震作用下出现理想的塑性机构。通过对1榀10层3跨的SPSW结构算例分析,采用弹塑性时程分析对所设计结构进行了验证。计算结果表明：结构最大楼层侧移平均值满足我国现行抗震规范的要求,与设计假定的目标侧移基本一致,验证了建议方法的合理性。     

Beam‐attached steel plate shear walls

Connecting to their surrounding beams and columns, unstiffened steel plate shear walls (SPSWs) are widely used as an appropriate lateral resisting system for designing and retrofitting of structures against lateral loads. The base philosophy for the performance of such systems, post‐buckling tension field formation, needs strong enough boundary elements to form. However, in some cases, relatively low performance demand needs panels with impractical thickness. To overcome the construction limitations, the designer is forced to use thicker plates, and consequently to satisfy the post‐buckling tension field philosophy, heavier column sections must be used. A novel configuration of steel shear walls, beam‐attached SPSWs, in which the size of the column section is released to be as a function of the plate thickness and removes the wasteful need for heavy columns, is proposed in this paper. Copyright © 2010 John Wiley & Sons, Ltd.     

Thin steel plate shear walls behavior and analysis

Steel plate shear walls have been used in buildings in North America and Japan. Until recently, the design practice has been to limit the strength of the wall to the buckling strength of the plate. The post-buckling strength of thin plates subjected to shear has been recognized for more than 60 years, since it was outlined by Wagner in the early 1930s. Tests of a quarter and one third scale specimens of thin steel plate shear walls under cyclic loading were performed; the tests are described and the results are summarized. An analytical model to determine the behavior of thin steel plate shear walls was developed and is given. The model is capable of depicting the behavior of walls with plates welded or bolted to the surrounding beams and columns of the building frame. Comparisons between the analytical and experimental results are made.     

Numerical investigation on ultimate shear strength of steel plate shear walls

Ultimate shear strength of steel plate shear walls, SPSW, was conventionally computed as the sum of base shear supported by in-fill plate and boundary frame elements. The base shear supported by the in-fill plate was computed assuming that it was fully yielded after buckling whereas the base shear supported by the boundary frame elements was computed by plastic analysis assuming uniform yielding mechanism. In this paper the ultimate shear strength of SPSW was investigated by the finite element method. A detailed three-dimensional finite element model was established using ANSYS software at which the in-fill plate and the boundary frame elements were modeled using finite strain iso-parametric shell elements. The analysis included material and geometric non-linearities. Numerical results obtained from cyclic and pushover loading of SPSWs were verified by comparison to test results published in the literature. A comprehensive parametric analysis was conducted to assess the effect of geometric and material parameters of the wall on its ultimate shear strength. Discrepancies between numerical results and conventional theory were attributed to interaction of in-fill plate and boundary frame elements at ultimate load. When the flexural rigidity of boundary frame elements decreased, the in-fill plate did not achieve full yield strength. On the other hand, the base shear supported by boundary frame elements increased when thicker in-fill plates were utilized. Numerical results were used to update the theoretical expression of ultimate shear strength of SPSWs. The proposed expression was assessed by comparison to test results published in the literature.     

半刚性连接钢框架-钢板剪力墙结构抗震性能试验研究

通过对半刚性连接框架-钢板剪力墙结构在水平反复荷载作用下的试验研究,得到了结构的滞回曲线、延性指标、水平刚度、梁柱应变、转角及各关键部位的变形。从耗能能力、刚度退化、承载力、延性等方面分析该种结构的抗震性能和耗能机理;依据应力分布、梁柱转角研究半刚性节点与钢板剪力墙的相互影响效果;分析结构的内力转换和破坏模式。结果表明：该结构具有良好的延性和耗能性能;半刚性节点在反复荷载作用下没有明显变形,节点刚度退化小,框架和钢板剪力墙协同工作良好;梁柱半刚性连接弱化了结构的整体刚度,框架自身承担的水平荷载有限;破坏模式为内填钢板剪力墙局部撕裂,拉力带作用明显,钢框架柱脚及梁柱半刚性连接部位形成塑性铰,框架整体呈弯曲破坏模式。图12表4参10     

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.