钢框架栓焊梁柱连接节点的抗震设计

节点设计是整个钢结构设计的重要环节,提高钢框架梁柱连接节点的抗震性能是整个钢结构抗震设计的重要内容.本文主要介绍了提高钢框架栓焊梁柱连接节点的抗震设计的主要措施,主要方法包括:通过加腋和加盖板对节点进行加强,提高节点承载力;对梁局部削弱,使塑性铰从节点区外移至梁上;改进节点区焊接孔构造形式,缓解局部应力集中;妥善处理弧板和垫板,减少焊缝缺陷.     

螺栓装配多高层钢结构梁柱连接抗震性能研究

对三个不同参数螺栓连接的多高层钢结构装配节点的抗震性能进行试验和有限元分析,获得以梁端荷载-位移表征的滞回曲线、骨架曲线、延性性能、转动能力、刚度退化曲线等,分析了法兰螺栓和盖板螺栓对试件受力性能的影响。试验和有限元分析结果表明：通过调整盖板螺栓数量和规格,可以实现梁柱刚性连接和变刚度连接,变刚度连接时,可实现多遇地震作用下不滑移,设防地震和罕遇地震作用下利用盖板与梁翼缘相对滑移耗散地震能量;通过分析螺栓接触面的滑移,认为盖板与梁翼缘滑移构造提高了梁端的变形能力,延性以及耗能能力,实现了摩擦耗能,可以用于抗震设防区结构中。     

装配整体式混凝土框架梁柱组合体抗震性能试验研究

为研究基于GB/T 51231-2016《装配式混凝土建筑技术标准》改进的新型配筋构造的装配整体式混凝土框架梁柱组合体的抗震性能,进行了 4个梁柱组合体试件的拟静力试验.试件的受力纵筋和箍筋均采用HRB500钢筋,且为满足易施工性的要求,试件中的预制柱采用大直径大间距纵筋,叠合梁采用大肢距组合封闭箍,后浇梁柱节点区则采...     

基于内聚力模型的FRP布加固混凝土梁柱子结构受力性能分析

FRP-混凝土界面力学性能是影响FRP加固结构承载力的重要因素。建立了可模拟FRP布加固结构黏结界面非线性软化力学行为的双线性内聚力单元,考虑混凝土与钢筋的材料非线性,进行了FRP布加固混凝土梁柱结构静力加载全过程有限元分析。分析了FRP布及黏结界面的应力变化、界面与结构破坏机制以及结构的承载力,与试验以及不考虑界面黏结滑移的有限元分析结果进行了比较,以验证方法的合理性,并提出了改进FRP环形箍布置方式。有限元分析结果表明：FRP布的拉应力、黏结界面应力与损伤变量等呈现节点区域大、跨中小的分布特点,剥离破坏随加载过程由节点域向跨中扩展,混凝土开裂后,FRP布与钢筋共同构成了悬链线机制;有限元分析所得结构破坏过程与试验的基本一致,揭示了黏结界面退化对FRP布加固混凝土结构受力性能的影响,所得各阶段最大荷载与试验结果的相对误差小于5%;不考虑黏结界面性能的退化与FRP布的剥离,则高估了悬链线阶段FRP布的贡献以及加固结构的承载力。黏结界面内聚力模型可为FRP布加固框架结构的受力性能分析提供参考。     

附加曲线钢板支撑的预制预应力混凝土装配式梁柱节点抗震性能

为研究附加曲线钢板支撑的预制预应力混凝土装配式梁柱节点的抗震性能,对不同截面宽度和不同偏心距离的附加曲线钢板支撑的预制预应力混凝土装配式梁柱节点,以及无支撑装配式梁柱节点对比试件进行低周往复荷载试验研究以及数值模拟分析,研究节点试件破坏形式、承载力、刚度、耗能等变化规律。结果表明：在层间位移角不大于5％时,节点试件具有稳定的受力性能,节点梁端混凝土压碎,同时曲线钢板支撑受弯屈服;曲线钢板支撑可提高预应力装配式梁柱节点试件的承载力、刚度和耗能,随着支撑截面宽度的增加以及偏心距离的减小,节点试件承载力、刚度和耗能逐渐提高;在层间位移角为4%时等效黏滞阻尼系数为0.12~0.20,相对无支撑预应力装配节点提高约2~3倍;在曲线钢板支撑偏心率小于0.3时,节点试件承载力受偏心距离影响较大,偏心率大于0.3时,承载力基本不变。     

梁柱节点处粘钢加固作法研究

介绍了一种新的异型钢板粘钢加固负弯矩区抗弯不足的作法,并对其与规范中作法进行了有限元分析对比,结果表明这种作法可以有效提高被加固梁的承载力,使挠度明显降低,并且有效地抑制了裂缝在构件中的开展,计算证明此方法有效且可靠.     

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 performance analysis and evaluation of tall structures using grille-type steel plate composite shear walls

Grille-type steel plate composite (GSPC) shear wall is an innovative wall system consisting of concrete cores, steel faceplates, steel tie plates, and steel channels with more advantages than conventional reinforced concrete (RC) walls, including better ductility, higher bearing capacity, and easy-modular characteristics. This paper mainly discusses the seismic performance and damage resistance of GSPC walls to the entire structure from the aspect of the structural level. Three nonlinear numerical models of high-rise structures with different structural heights and types were established by PERFORM-3D software to study the influence of GSPC walls on the change in structural internal forces and deformations compared with RC walls. One of these structures was selected to conduct the seismic fragility analysis based on the incremental dynamic analysis and to assess the structure's seismic performance with GSPC walls. Finally, the seismic damage prediction method was used to evaluate the damage levels of the GSPC wall structure. Results indicate that the structures with GSPC walls suffer more significant seismic forces than those with RC walls, although they experience lesser structural deformations. Moreover, GSPC walls can effectively improve the structure's collapse and seismic damage resistance.     

纤维增强复合材料加固混凝土柱研究综述

从纤维增强材料(FRP)约束混凝土柱的本构关系,FRP加固轴心受压和偏心受压构件的影响因素,力学性能、抗震性能等几个方面总结了该加固方法的国内外研究现状,分析了在FRP加同混凝土柱的研究中存在的问题,明确了需进一步开展研究工作的方向.     

Seismic retrofit of square reinforced concrete piers by ferrocement jacketing

An experimental investigation was conducted to strengthen shear deficient reinforced concrete columns using ferrocement jacketing. Three scale model specimens, identical to the actual bridge piers, were tested. One of the piers was tested under as-built condition while the other two were strengthened with layers of wire mesh before being tested. All the specimens were subjected to a simulated seismic loading and constant axial load. It was observed from the experimental results that the ferrocement-jacketed specimens exhibited enhanced stiffness, strength, energy dissipation and ductility and the mode of failure changed from brittle shear failure to a ductile flexural failure. The control specimens failed by shear at a relatively low lateral displacement. A finite element model was developed and the results obtained from the numerical analysis compared well with the experimental results. A design methodology for strengthening piers with square/rectangular columns with inadequate shear strength using ferrocement jackets is also presented.     

Modified continuity conditions of plates in beam-column using the Mindlin plate theory

In the present paper, two independent functions of displacements along the z axis direction, i.e., the total lateral displacement w and the bending deflection φ, have been introduced within the first order shear deformation plate theory FSDT. The differential equations of motion and boundary conditions have been derived from Hamilton's principle employing the classical Mindlin approach. Modified conditions of two adjacent component plate interactions have been formulated. A plate model of the plate structure has been adopted to describe all possible buckling modes. The obtained equations are approximate since the shear locking is not ignored but the boundary layer effect is neglected. A method of the modal solution to the buckling problem within Koiter's asymptotic theory has been used. The calculations have been conducted for a few beam-columns of various shapes of cross-sections. The obtained results that account for transverse shear deformation have been compared to the results attained for the classical thin plate theory.     

冷弯薄壁型钢-钢板剪力墙抗震性能试验研究

为研究冷弯薄壁型钢-钢板剪力墙结构的抗震性能,对冷弯薄壁型钢边柱内置薄钢板剪力墙进行低周往复加载试验,对比不同边柱截面厚度及截面形式对其抗震性能的影响。试验中得到了冷弯薄壁型钢-钢板剪力墙的破坏形态、荷载-位移滞回曲线、骨架曲线、荷载及位移特征值,并对结构的破坏特征、延性、耗能能力、承载力及刚度退化进行分析。结果表明:冷弯薄壁型钢-钢板剪力墙具有良好的抗震性能;增加边柱截面厚度及选用帽形边柱均可提高剪力墙的承载力、刚度及耗能性能。计算3个试件受剪承载力设计值和弹性抗侧刚度,其值均高于常用冷弯薄壁组合墙体的;结合破坏特征提出冷弯薄壁型钢-钢板剪力墙3个受力阶段;边柱对剪力墙破坏起控制因素,工程设计中应保证边柱承载能力,宜采用"强边柱、弱钢板"的设计理念。     

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.     

四角钢连接钢框架-钢板剪力墙结构抗震性能研究

基于半刚接框架-钢板剪力墙试件的低周反复加载试验,采用ANSYS有限元软件对其滞回性能进行了数值模拟。分析循环荷载作用下试件的滞回性能及承载能力,考察其应力、变形发展历程、耗能机理和破坏模式。试验和有限元分析结果均表明：内填板的设置缓解了节点区自身的延性要求,框架和钢板墙协同工作良好,结构体系耗能优异,安全储备高,是一种理想的抗侧力结构体系。有限元模拟结构应力和变形发展历程与试验结果基本吻合。由于初始偏心、焊接残余应力等原因,弹性工作阶段,有限元分析的峰值荷载与试验值比较接近;进入塑性阶段,有限元分析的峰值荷载比试验值大,滞回环更饱满。     

Statistical evaluation of steel beam-column resistance

Statistical data on uniaxial and biaxial bending of beam-columns is compared with existing interaction equations in several standard specifications. The mean values and coefficients of variation for the professional factors of these equations are evaluated. An alternative set of ultimate strength parameters for use in the equations are proposed, to reduce the scatter in the availble data. The validity of the proposed interaction equation is confirmed.     

Seismic performance of corrugated steel plate concrete composite shear walls

In this paper, composite shear walls with different encased steel plates (flat, horizontal corrugated, and vertical corrugated) were tested and simulated by Abaqus to investigate the seismic behavior of corrugated steel plate concrete composite shear walls (SPCSWs). The failure characteristics, deformation and energy dissipation capacity, and stiffness and bearing capacity of the structures under low‐frequency cyclic load were analyzed, and indexes of the seismic performance were obtained. The formulas of the shear‐bearing capacity of steel plate concrete composite shear walls are suggested, and the shear‐sharing ratio of each member is obtained. According to the obtained results, corrugated steel plates can bond with concrete well, and the bearing capacity of the vertical corrugated SPCSW are higher than that of the horizontal corrugated SPCSW. Compared with flat SPCSW, corrugated SPCSW has higher initial stiffness and lateral stiffness, better ductility and energy dissipation ability, and the degradation of bearing capacity and stiffness is slower. The shear‐sharing ratio of a steel plate is larger than that of reinforced concrete in the flat SPCSW and the vertical corrugated SPCSW, the shear force shared by steel plate and reinforced concrete in horizontal corrugated SPCSW is basically the same.     

FRP单面加固带裂纹钢板的应力强度因子分析

对单面粘贴FRP的带裂纹钢板进行了线弹性断裂力学分析,研究了裂纹尖端的应力强度因子变化,分析结果表明,经过FRP加固后,钢板的应力强度因子显著降低;随着FRP刚度的增加,应力强度因子逐渐减小。     

Seismic retrofitting of severely damaged RC connections made with recycled concrete using CFRP sheets

An experimental and numerical program is carried out in this research to investigate the influence of CFRP sheets on the cyclic behavior of unconfined connections made with recycled concrete. Cement is partially replaced by silica fume, iron filling and pulverised fuel ash using two different percentages: 15% and 20%. Each specimen is partially loaded at the first stage and then specimens are repaired using CFRP sheets. The repaired specimens are then laterally loaded until failure. In addition, a finite element model is built in ABAQUS and verified using the experimental results. The experimental results have shown that the repaired specimens have regained almost double the capacity of the un-repaired specimens and hence the adopted repair configuration is recommended for retrofitting seismically vulnerable RC connections. Increasing cement replacement percentage by silica fume, fuel ash or iron filling from 15% to 20% has reduced joint carrying capacity and weakened the joint. It is recommended using 15% pulverised fuel ash or silica fume as cement partial replacement to enhance the strength and ultimate drift of beam-column joints under cyclic loading. Iron filling concrete is also recommended but the enhancement is relatively less than that found with pulverised fuel ash concrete and silica fume concrete.     

Seismic retrofitting of old‐type RC columns with different lap splices by NSM GFRP and steel bars

This paper describes the experimental results from flexural strengthening of old‐type concrete columns reinforced with plain bars and different lap splices constructed before the 1970s. Nine half‐scale column specimens were tested under combined constant axial and quasi‐static cyclic lateral loads. The specimens included 3 control specimens and 6 other specimens strengthened via near surface mounted technique with glass‐fiber reinforced plastic and steel bars. The effect of different longitudinal bar lap splices of columns and the type of strengthening materials were also investigated. The results indicated that the proposed strengthening method significantly increases the flexural strength and improves the seismic parameters, for example, energy dissipation and hysteresis damping. The specimens strengthened with steel bars presented higher strength, ductility, and hysteresis damping compared to those strengthened with glass‐fiber reinforced plastic bars. The formation of struts at the control specimen with hooked lap splices caused severe damages at the spliced region; if appropriate wrapping is done at the column end, these damages will be constrained. Using steel bars as near surface mounted reinforcement, utilizing epoxy resins as bonding agent, and installing fiber‐reinforced polymer wrapping at the end of column will all make a more effective strengthening method. Finally, an analytical work was presented for predicting the capacity of test specimens, and the comparison between experimental results and theoretical predictions showed a good agreement.     

钢框架-防屈曲开斜槽耗能钢板剪力墙装配式结构体系抗震性能分析

防屈曲开斜槽耗能钢板剪力墙(简称开斜槽钢板墙)是一种新提出的抗侧力构件,相比于普通钢板剪力墙,具有多个可调参数、耗能稳定且延性好的优点,并可作为装配式单元,通过组装单元的方式形成装配式剪力墙结构,进一步形成不同的装配式抗侧力体系。本文介绍了钢框架-开斜槽钢板墙装配式结构体系,包括开斜槽钢板墙设计方法,装配式剪力墙结构以及结构体系设计方法,并以20层办公大楼为例进行设计,对结构在小震和大震下的抗震性能进行分析。计算结果表明,开斜槽钢板墙可提供较大的抗侧刚度,能充分发挥耗能作用,保护主体结构安全,符合双重抗侧力体系的原则,该结构体系具有优越的抗震性能。