半刚接钢框架内填RC墙结构滞回性能试验——整体性能分析

半刚接钢框架内填钢筋混凝土剪力墙结构(简称PSRCW)在低周反复荷载作用下抗剪栓钉易发生疲劳断裂,从而使结构后期承载力衰减过快,延性较差。为了进一步改善结构的延性性能,采用槽钢、U形钢筋及抗剪栓钉三种不同形式的抗剪连接件,通过3榀1/3缩尺、两层、单跨PSRCW试件的低周反复荷载试验,重点研究抗剪连接件对结构性能的影响,分析结构的传力机理、破坏模式、滞回性能、刚度退化、变形及延性、耗能能力等。试验结果表明:加载过程中,抗剪连接件未发生疲劳断裂,试件的后期承载力退化缓慢,试件的变形能力、延性性能以及耗能能力均得到大幅提高,试件呈内填墙压碎的延性破坏模式。抗剪连接件的抗剪能力应与混凝土内填墙的抗剪能力相协调,内填墙混凝土强度等级不宜过高,避免抗剪连接件的破坏模式由剪断控制。PSRCW结构中抗剪连接件不发生疲劳断裂是结构发生延性破坏的重要前提。     

半刚接钢框架内填暗竖缝钢筋混凝土剪力墙结构滞回性能试验研究

为了进一步改善半刚接钢框架内填钢筋混凝土剪力墙结构（PSRCW）的抗震性能,将暗竖缝引入PSRCW结构的内填墙中,进行了1榀1∶3缩尺内填墙带暗竖缝PSRCW结构的低周反复荷载试验,研究了带暗竖缝PSRCW结构的破坏机理及滞回性能。试验结果表明：内填墙设置暗竖缝对PSRCW结构的初期刚度影响较小,峰值荷载过后承载力退化缓慢,结构延始性能得到显著改善。带暗竖缝的PSRCW结构通过合理设计可以实现控制结构小震或中震作用下的变形,提供较大的初始抗侧刚度,大震下提供良好的变形能力和耗散地震能量的双重功能。     

半刚接钢框架内填不同构造措施钢筋混凝土墙子结构抗震性能试验研究

为研究半刚接钢框架内填RC墙结构的抗震性能,提出了一种考虑内填墙边界条件的子结构模型,进行了3榀1/3缩尺的3层单跨半刚接钢框架内填RC墙子结构的低周往复加载试验,研究了不同构造内填RC墙对结构抗震性能的影响,得到了试件的滞回曲线、骨架曲线、位移延性系数、刚度退化、耗能能力及水平剪力分配。试验结果表明:内填贯通竖缝RC墙及暗竖缝RC墙试件的滞回曲线饱满,耗能能力强,但水平承载力及抗侧刚度略低,破坏模式均为缝间墙的弯曲破坏;内填实体RC墙试件的滞回曲线捏缩明显,耗能能力较弱,但水平承载力及抗侧刚度较高,破坏模式为内填墙的剪切破坏;内填墙降低了地震作用下周边框架节点转动能力,半刚性节点的最终塑性转角不超过0.025 rad,可避免钢框架节点失效导致的脆性破坏。内填墙承担约80%的水平荷载,但随着水平荷载的增大逐渐降低。     

钢框架内填预制钢筋混凝土剪力墙试验研究

为改进钢框架内填预制钢筋混凝土剪力墙的抗震性能,将耳板装置引入钢框架与内填墙的连接中.通过2个2层单跨钢框架内填预制钢筋混凝土剪力墙1/3模型试件的循环荷载试验,考察耳板连接装置的可靠性和内填墙裂缝的开展与结构变形能力,分析结构的破坏机理、滞回性能、刚度退化、变形及延性等,并对钢框架内填预制混凝土剪力墙体系与现浇混凝土剪力墙体系和带竖缝混凝土剪力墙体系进行对比.研究结果表明:抗剪连接件(U形筋)在梁柱节点上下耳板的帮助下未发生破坏,耳板连接装置具有可靠的工作性能;合理设计的钢框架内填预制钢筋混凝土剪力墙结构具有良好的延性.     

钢框架内填预制带竖缝钢筋混凝土剪力墙抗震性能试验研究

为改进钢框架内填预制带竖缝钢筋混凝土剪力墙的抗震性能,将耳板引入钢框剪与内填墙的连接中。通过2个两层单跨缩尺比为1∶3的钢框架内填预制带竖缝钢筋混凝土剪力墙模型试件的拟静力试验研究,考察了耳板连接的可靠性和内填墙裂缝的开展与结构变形能力,分析了结构的破坏机理、滞回性能、刚度退化、变形及延性和耗能能力等。试验结果表明：抗剪连接件(U形筋)在梁柱节点上下耳板的连接处未发生破坏,耳板连接具有可靠的工作性能;钢框架带竖缝剪力墙结构具有良好的延性,平均位移延性系数大于3;内填墙的承载力由竖缝根部的剪切破坏控制。     

预制RC框架内嵌带竖缝剪力墙结构抗震性能研究

为研究预制钢筋混凝土框架内嵌带竖缝剪力墙(PRCFW)结构的抗震性能,对2个单跨两层、缩尺比为1∶2的PRCFW试件进行了拟静力试验研究。考察了PRCFW结构的变形和延性、滞回耗能能力、承载力及刚度退化等性能,分析了框架与内填墙之间的抗剪连接件对结构整体性能的影响。试验结果表明：在加载过程中,设计的抗剪连接件性能可靠,未发生疲劳剪断或锚固破坏;内填墙设置竖缝对PRCFW结构的初期刚度影响较小;进入屈服段后,预制竖缝阻碍了斜裂缝的发展和贯通,缝间墙段以弯曲变形为主,承载力和刚度退化缓慢,使结构整体具有良好的延性和耗能能力。不同轴压比下的框架柱和现浇节点基本完好,破坏主要发生在内填墙和梁端。结合试验和分析结果,提出了PRCFW结构在工程设计时的若干补充计算及构造措施建议。     

半刚接钢框架内填RC墙结构抗震设计方法(Ⅰ)——理论

半刚接钢框架内填RC墙结构(简称PSRCW)是一种抗震性能优良的新型组合结构体系,为推广其工程应用,文中提出了PSRCW结构的两阶段抗震设计方法:1多遇地震水准下结构的弹性设计法——用于初步确定PSRCW结构主要受力构件的截面;2罕遇地震水准下结构的能力设计法——用于确保PSRCW结构进入弹塑性阶段出现理想的破坏模式。根据已有的试验结果,提出PSRCW结构的理想塑性屈服机构,建立罕遇地震水准下RC内填墙周边钢构件能力设计的简化计算公式,给出设计步骤。文中设计方法的合理性验证见另文。     

半刚接钢框架-钢板剪力墙结构滞回性能的有限元分析

为研究半刚接钢框架-钢板剪力墙结构(Partially-restrained Steel Frame Steel Plate Shear Wall)的抗震性能,利用经试验验证的双向等效拉杆模型分析了低周往复荷载作用下梁柱半刚性连接对强、弱框架SPSW结构滞回性能、承载力、刚度、耗能能力的影响.分析结果表明:SPSW结构的滞回曲线具有双重特征,当周边钢框架较强时,滞回曲线趋于饱满;当内填剪力墙板较强时,滞回曲线趋于捏缩.随着节点抗弯承载力的增加,强、弱框架的SPSW结构的滞回性能趋于饱满,耗能能力增强,水平承载力呈增大趋势,但对强框架SPSW结构的影响程度大于弱框架SPSW结构.节点抗弯承载力对强框架SPSW结构的抗侧刚度影响较大,对弱框架SPSW结构抗侧刚度影响相对较小.     

考虑材料变异性的半刚接钢框架内填RC墙结构的强度折减系数研究

为合理评估半刚接钢框架内填RC墙结构(简称PSRCW)的延性及强度折减系数，文中利用Latin超立方抽样方法考虑PSRCW结构中型钢、钢筋及混凝土材料力学性能的随机性，提出一种基于Pushover方法评估PSRCW结构延性及强度折减系数的概率方法。根据现行抗震设计规范设计4组160个PSRCW算例样本，重点考察了层数、抗震设防烈度、水平荷载分布模式等因素的影响，利用Pushover方法确定160个PSRCW算例的抗侧能力曲线，基于概率方法按置信水平为95%的单侧置信下限确定PSRCW结构的延性及强度折减系数。研究结果表明，随着层数的增加，PSRCW结构的延性及强度折减系数均呈降低趋势；设防烈度对PSRCW结构的延性折减系数影响不明显，但对强度折减系数影响较大；均匀分布模式作用下确定的PSRCW结构的延性及强度折减系数均显著大于按广义乘方分布模式的分析结果。     

半刚接钢框架内填RC墙结构抗震设计方法(Ⅱ):算例

作者在文献[1]中提出了半刚接钢框架内填RC墙结构(简称PSRCW)的两阶段抗震设计方法。该文用此方法设计了1榀6层3跨PSRCW结构,采用塑性机构法、Pushover分析方法及弹塑性时程法对设计算例进行了地震反应分析,评估了算例结构的抗震性能。结果表明:塑性机构法同采用组合斜压板带模型所得到的极限水平承载力相近,结构的整体超强系数为3.34,具有较大的抗侧能力和超强性能。在多遇及罕遇地震下结构的层间侧移比满足现行抗震规范要求,结构具有良好的抗震性能,进一步证明了PSRCW结构的两阶段抗震设计方法的合理性。     

Finite element modeling and parametric analysis of timber–steel hybrid structures

This paper presents finite element modeling and a parametric analysis of prototype timber–steel hybrid structures, which are composed of steel moment‐resisting frames and infill wood‐frame shear walls. A user‐defined element was developed to model the behavior of the infill wood shear walls based on the concept of pseudo‐nail model. The element was implemented as a subroutine in a finite element software package abaqus . The model was verified by reversed cyclic test results and further used in a parametric analysis to investigate the lateral performance of timber–steel hybrid shear walls with various structural configurations. The results showed that the infill wall was quite effective within small drift ratios, and the elastic lateral stiffness of the hybrid shear wall increased when a stronger infill wall was used. In order to ensure the structural efficiency of the hybrid shear wall system, it is beneficial to use relatively strong timber–steel bolted connections to make sure the shear force can be transferred effectively between the steel frame and the infill wall. Copyright © 2013 John Wiley & Sons, Ltd.     

Cyclic behavior of partially-restrained steel frame with RC infill walls

In order to investigate the behavior of partially-restrained steel frame with RC infill wall (PSRCW), two specimens with one-third scale, one-bay, and two-story were performed under reversed cyclic lateral load, where one specimen was with concealed vertical slits in the infill walls and another specimen with solid infill walls. Test results showed that both specimens obtained enough lateral stiffness for controlling drift and yielded enough strength appropriate for resisting lateral load. PSRCW with solid infill walls exhibited moderate ductility capacity and energy dissipation due to the degradation of post-peak strength. PSRCW with concealed vertical slits exhibited much larger ductility, deformability, and energy dissipation capacity than the other one. Once concealed vertical slits were crushed, infill walls behaved as a series of flexural columns provided fairly ductile response and stable cyclic performance. PSRCW with concealed vertical slits can improve post-peak strength degradation considerably. In addition, damaged PSRCW structure subjected to earthquake is easy to be repaired, through knocking off the heavy crushed infill walls and recasting concrete infill walls. This is another advantage of this composite structure.     

Experimental study on separating reinforced concrete infill walls from steel moment frames

In a multistory building frame, stiff reinforced concrete (RC) infill walls may be terminated above the first story for architectural purposes, which may create a soft-first-story structure. To eliminate this detrimental situation, this paper proposes to separate the RC infill wall from the steel moment frame by slits. An experimental program of four one-bay-by-one-story steel moment frame specimens along with pushover analyses of multistory frame models were presented to validate the proposed idea. This study conducted cyclic loading tests on a total of four moment-resisting-frame specimens, which included one bare frame; one with ordinary RC infill wall; and two with side slits between RC wall and frame members. Furthermore, pushover analyses of multistory frame models with soft first story configurations were also conducted to illustrate the effect of RC infill walls with or without slit separation. Both experimental and analytical results showed that the stiff RC infill wall dominated the lateral resistance and drift capacity of the test specimens, and that by adding slit-separated features at the edges of infill walls improved the drift capacity. It is concluded that the slit-separated features can be a viable option to eliminate the soft-story problem caused by vertically irregular configuration of RC infill walls.     

Cyclic behavior of partially-restrained steel frame with RC infill walls

In order to investigate the behavior of partially-restrained steel frame with RC infill wall (PSRCW), two specimens with one-third scale, one-bay, and two-story were performed under reversed cyclic lateral load, where one specimen was with concealed vertical slits in the infill walls and another specimen with solid infill walls. Test results showed that both specimens obtained enough lateral stiffness for controlling drift and yielded enough strength appropriate for resisting lateral load. PSRCW with solid infill walls exhibited moderate ductility capacity and energy dissipation due to the degradation of post-peak strength. PSRCW with concealed vertical slits exhibited much larger ductility, deformability, and energy dissipation capacity than the other one. Once concealed vertical slits were crushed, infill walls behaved as a series of flexural columns provided fairly ductile response and stable cyclic performance. PSRCW with concealed vertical slits can improve post-peak strength degradation considerably. In addition, damaged PSRCW structure subjected to earthquake is easy to be repaired, through knocking off the heavy crushed infill walls and recasting concrete infill walls. This is another advantage of this composite structure.     

低屈服点钢板剪力墙抗震性能研究

在低屈服点钢板剪力墙体系中,内嵌钢板使用低屈服点钢,周边框架使用普通钢材。采用数值方法研究低屈服点钢板剪力墙在单调荷载作用下的抗剪性能和在反复周期荷载作用下的滞回性能。对内嵌钢板的屈服强度和高厚比进行参数分析,用于研究其对结构抗震性能的影响;分析显示低屈服点钢板剪力墙有很好的变形能力和耗能性能且能减小对主框架的影响。     

Experimental Study on Low Cyclic Loading Tests of Steel Plate Shear Walls with Multilayer Slits

A new type of earthquake-resisting element that consists of a steel plate shear wall with slits is introduced. The infill steel plate is divided into a series of vertical flexural links with vertical links. The steel plate shear walls absorb energy by means of in-plane bending deformation of the flexural links and the energy dissipation capacity of the plastic hinges formed at both ends of the flexural links when under lateral loads. In this paper, finite element analysis and experimental studies at low cyclic loadings were conducted on specimens with steel plate shear walls with multilayer slits. The effects caused by varied slit pattern in terms of slit design parameters on lateral stiffness, ultimate bearing capacity and hysteretic behavior of the shear walls were analyzed. Results showed that the failure mode of steel plate shear walls with a single-layer slit was more likely to be out-of-plane buckling of the flexural links. As a result, the lateral stiffness and the ultimate bearing capacity were relatively lower when the precondition of the total height of the vertical slits remained the same. Differently, the failure mode of steel plate shear walls with multilayer slits was prone to global buckling of the infill steel plates; more obvious tensile fields provided evidence to the fact of higher lateral stiffness and excellent ultimate bearing capacity. It was also concluded that multilayer specimens exhibited better energy dissipation capacity compared with single-layer plate shear walls.     

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.     

Shear capacity prediction of steel plate shear walls with precompression from columns

This paper investigates the shear capacity of the unstiffened steel plate shear walls with gravity loads from the adjacent boundary columns that is produced during the construction process. The distribution and transferring of gravity loads between boundary columns and the infill steel plate are proposed. Then, the infill steel plate is partitioned into 3 zones bounded on the effective length, the inclination angle, and shear capacity of each zone that is proposed and discussed, and the shear capacity of the infill steel plate is summed over the 3 zones. Finally, based on the three specimens tested by Park et al. (2007), shear capacity prediction of 18 more numerical steel plate shear wall specimens with the axial stresses of the boundary columns equal to 50 MPa, 100 MPa, 150 MPa, 200 MPa, 250 MPa, and 300 MPa are analyzed.     

考虑全填充墙作用的钢筋混凝土框架抗连续倒塌性能分析

为探究钢筋混凝土(RC)全填充墙框架在边中柱失效情况下的抗连续倒塌性能及其承载力计算方法,基于已有试验和有限元程序OpenSees建立宏观有限元数值模型展开研究。数值模型中的梁柱采用基于力的纤维梁单元模拟,填充墙则转化为等效斜撑并用桁架单元进行表征。填充墙宏观模型涉及等效斜撑的宽度、数量和相应材料属性的确定,为此对比了不同等效斜撑模型的适用性,确定了一种连续倒塌工况下全填充墙的宏观模拟方案。进而利用验证的数值模型,揭示全填充墙框架防倒塌的荷载传递机制,并研究了层数和填充墙砌体抗压强度对抗倒塌性能的影响。结果表明：全填充墙框架荷载主要通过墙体对角传递且全填充墙会与周围框架形成一种桁架机制;随填充墙砌体抗压强度降低,结构抗力峰值呈下降趋势。最后,以填充墙和周边框架竖向承载刚度比为基本参数,建立了通过求得填充墙和框架刚度以及纯框架理论弯曲承载力,便可快速评估规则RC填充墙框架防倒塌能力的回归模型。