波形钢板-混凝土组合剪力墙抗震性能试验研究

为研究波形钢板-混凝土组合剪力墙的抗震性能,完成了竖向波形钢板-混凝土组合剪力墙、水平波形钢板-混凝土组合剪力墙以及平钢板-混凝土组合剪力墙拟静力试验,研究了波形钢板-混凝土组合剪力墙在低周往复荷载作用下的变形能力和破坏模式,分析了荷载-位移滞回曲线、骨架曲线、各阶段特征荷载和位移值等,以及结构的破坏特征、变形和耗能能力、刚度和承载力退化。试验结果表明：波形钢板-混凝土组合剪力墙具有较大的抗侧刚度、较好的延性和耗能能力;与平钢板-混凝土组合剪力墙相比,波形钢板-混凝土组合剪力墙有较好的界面黏结性能,而平钢板-混凝土剪力墙由钢板变形引起的混凝土剥落严重;波形钢板-混凝土组合剪力墙的初始刚度较平钢板-混凝土组合剪力墙的高,竖向波形钢板-混凝土组合剪力墙的承载力和极限位移较水平波形钢板-混凝土组合剪力墙的高,波形钢板-混凝土组合剪力墙的承载力退化和刚度退化比平钢板-混凝土组合剪力墙的慢,表现出较好的受力性能。采用ABAQUS有限元软件可以较好地模拟试验,有限元分析结果表明,波形钢板的应力分布比较均匀,组合作用效应明显,适合在抗震结构中采用。     

Behavior of steel-concrete composite cantilever beams with web openings under negative moment

The effect of web openings on the mechanical behavior of composite beams under negative moment was studied through monotonically loading tests. Nonlinear finite element method based analysis was also conducted for cantilever composite beams. The test and the finite element analysis results indicated that the initial cracking loads of composite beams with web opening are lower than that without web opening. The first crack initiated from the concrete slab on the top of the opening. The beams with web opening failed due to shear failure of concrete slab upon the opening. It was also found that the load carrying capacity of beam decreases with the increase of the moment-to-shear ratio at the central line of the opening and the mechanical behavior of beam can be improved significantly by applying stiffening steel plates around the opening. To quantify the reduction of load carrying capacity, a method for calculating the load carrying capacity of beams with web openings under negative moment was derived with consideration of the interaction between moment and shear. Good consistency was obtained between the proposed method, the finite element method and the test results.     

Study on mechanical behavior of a new type of hollow composite pylon

为研究外包钢中空混凝土柱组合桥塔在轴压荷载下的受力性能,进行模型试验和有限元分析,研究了破坏形态、荷载-变形关系和传力机理等。研究结果表明：该组合桥塔能够充分发挥混凝土和钢材的承载能力,其变形能力得到提高;钢壁板荷载逐渐传递至中空混凝土,且荷载传递主要发生在桥塔上部;钢-混凝土结合面上的开孔板连接件,不仅受剪发挥传递荷载作用,其抗拉拔作用还能阻止局部屈曲破坏前钢壁板与混凝土柱的剥离;顶部开孔板刚度折减后,连接件剪力竖向分布趋于均匀;承压板构造有利于荷载传递、扩散,使底座混凝土受力均匀。     

复合墙板受力性能平面有限元分析

对三组复合墙板试件进行了平面有限元分析并与拟静力试验结果进行了比较,分析了骨架曲线、墙板裂缝分布及发展、钢筋应力分布等。分析表明,由斜拉筋连接的复合墙板在边框的约束下各部分能够很好地共同工作,其受力性能接近或优于普通实心剪力墙,为将复合墙板简化为普通实心剪力墙进行设计提供了试验和理论依据。边框面积的增大以及边框配筋的增加在一定程度上可以大大提高复合墙板的承载能力以及延性耗能性能,但要注意边框尺寸和配筋的匹配问题。     

New evaluation and modeling procedure for horizontal shear bond in composite slabs

A new method for modeling the horizontal shear bond in steel deck-concrete composite slabs is proposed. The method considers the slab slenderness as the strength parameter that affects the accuracy of horizontal shear bond modeling. A calculation procedure called the Force Equilibrium method is developed to generate shear bond stress versus end slips relationship (shear bond property) from bending tests. An interpolation procedure is also presented to estimate the shear bond property curves for slabs of varying slenderness using two sets of bending test data. The shear bond property curves are applied to connector elements of finite element models to model the horizontal shear bond behavior in composite slabs. The results of this study show that the shear bond of composite slabs under bending varies with the slenderness parameter, and hence influences the slab strength and behavior, as well as affecting the accuracy of the finite element analyses. The finite element analyses conducted on slabs with different slenderness utilizing a single shear bond property, which are not varied according to the slenderness parameter, may lead to either safe or unsafe results, depending on the geometry of the slabs.     

Nonlinear finite element analysis of concrete filled steel plate composite coupling beams: force and deformation mechanics

在外包钢板-混凝土组合连梁试验研究的基础上,对组合连梁试件和不同参数取值的补充模型进行了非线性有限元分析。有限元分析得到的滞回曲线与试验曲线吻合良好,能较好地模拟组合连梁的受力行为。通过应力分析,发现内填混凝土的工作机制类似于斜压杆,其压力沿着连梁对角线方向从一端的受压侧传递到另一端的受压侧。外包钢板承担的剪力比例和弯矩比例的范围分别为0.36~0.76和0.57~0.82;混凝土的剪力与轴压力之比和连梁的高跨比近似相等。连梁的侧向位移由节点区变形引起的梁端转角、连梁的弯曲变形与剪切变形产生;在常用的跨高比范围内,剪切变形产生的侧向位移在总位移中占有较大比例,且受跨高比的影响很大。     

方钢管约束型钢混凝土柱受剪承载力计算

基于已有受剪破坏方钢管约束型钢混凝土短柱试验结果,建立精细化有限元模型,对设有型钢栓钉与钢管斜拉加劲肋的方钢管约束型钢混凝土短柱受剪性能进行有限元分析。研究结果表明:栓钉对方形截面钢管约束型钢混凝土短柱的力学行为影响较小;而斜拉加劲肋有效限制钢管局部屈曲,提高约束作用,改善型钢与混凝土的共同工作性能。基于试验与有限元分析结果,考虑方钢管等效密排箍筋效应,提出了方钢管约束型钢混凝土短柱的受剪承载力计算公式,预测结果与试验及有限元参数分析结果吻合较好。     

薄壁钢管混凝土梁-柱的钢板局部屈曲分析

高强钢和混凝土的应用,使得薄钢板开始应用在填充混凝土的钢管梁柱中。然而,在组合梁柱中薄钢板的应用可能会增加局部屈曲,这将减弱这些构件的强度和延性性能。通过有限元分析方法,分析了在填充混凝土的薄壁钢管梁-柱中钢板的临界局部屈曲和局部屈曲后性能。运用几何和材料非线性分析来研究在压力和平面内弯曲作用下钢板中的临界局部和后张局部屈曲强度。非线性分析中考虑了钢板的初始几何缺陷和残余应力,材料屈服和应变硬化。基于非线性有限元分析结果,本文提出一组设计公式,以确定这种组合梁柱的临界局部屈曲和钢板的极限强度。此外,还提出在不均匀压力作用下,钢板极限强度设计中有效宽度的计算公式。这一组设计公式可以直接用于组合梁-柱的设计和考虑局部屈曲作用后的薄壁钢管混凝土梁-柱分析。     

Local buckling of steel plates in concrete-filled thin-walled steel tubular beam-columns

The availability of high strength steels and concrete leads to the use of thin steel plates in concrete-filled steel tubular beam-columns. However, the use of thin steel plates in composite beam-columns gives a rise to local buckling that would appreciably reduce the strength and ductility performance of the members. This paper studies the critical local and post-local buckling behavior of steel plates in concrete-filled thin-walled steel tubular beam-columns by using the finite element analysis method. Geometric and material nonlinear analyses are performed to investigate the critical local and post-local buckling strengths of steel plates under compression and in-plane bending. Initial geometric imperfections and residual stresses presented in steel plates, material yielding and strain hardening are taken into account in the nonlinear analysis. Based on the results obtained from the nonlinear finite element analyses, a set of design formulas are proposed for determining the critical local buckling and ultimate strengths of steel plates in concrete-filled steel tubular beam-columns. In addition, effective width formulas are developed for the ultimate strength design of clamped steel plates under non-uniform compression. The accuracy of the proposed design formulas is established by comparisons with available solutions. The proposed design formulas can be used directly in the design of composite beam-columns and adopted in the advanced analysis of concrete-filled thin-walled steel tubular beam-columns to account for local buckling effects.     

分块盖板屈曲约束钢板剪力墙受力性能与设计方法研究

为考察分块盖板屈曲约束钢板剪力墙的抗震性能,采用非线性有限元分析软件ABAQUS对其受力机理进行深入研究。将板墙的高宽比、盖板厚度比等参数作为变量,对屈曲约束钢板墙在水平往复荷载作用下的抗震性能进行分析,考察内嵌钢板面外变形与应力、盖板变形与钢筋应力。分析结果表明:采用非线性有限元数值模拟得到屈曲约束钢板剪力墙的滞回性能、内嵌钢板变形特性均与试验结果较为接近。分块盖板屈曲约束钢板剪力墙在层间位移角接近1/300时进入屈服;加载至层间位移角1/50时,滞回曲线接近于理想弹塑性。当盖板厚度比t_c/t_w不小于7时,可以形成对内嵌钢板面外变形的有效约束,钢板屈曲半波长度与钢板厚度之比λ/t_w基本保持不变。在此基础上,建立内嵌钢板与分块盖板简化计算模型,根据内嵌钢板主压应力推导出挤压应力计算公式,从而可以方便地确定对拉螺栓的内力与分块盖板的弯矩。简化计算方法与有限元数值模拟得到混凝土盖板弯矩的分布规律非常接近,简化计算方法偏于安全。     

型钢再生混凝土柱-钢梁组合框架节点受力性能非线性分析

在型钢再生混凝土柱-钢梁组合框架节点拟静力试验基础上,采用ABAQUS有限元软件建立了组合框架节点的数值计算模型,对该组合框架节点在水平荷载作用下的受力非线性行为进行了有限元分析,获取了组合框架节点的破坏过程、破坏形态、应力云图、荷载-位移曲线及荷载特征值,并对节点的承载力计算值与试验值进行了比较,验证了有限元计算模型的合理性,进而分析了有限元拓展参数对组合框架节点受力性能的影响规律。结果表明:有限元计算结果与试验结果吻合较好,该有限元模型能较好地模拟该组合框架节点在水平荷载作用下的受力性能;另外,提高再生混凝土强度或者箍筋强度对组合框架节点的抗剪承载力是有利的,但节点的延性变形能力有所降低;组合框架节点的抗剪承载力随着型钢强度的提高而显著增加,但节点的变形能力变化不大;增加体积配箍率或型钢配钢率可以明显提高组合框架节点的抗剪承载力和变形能力。     

轴压比对钢管混凝土边框组合剪力墙的影响

介绍了钢管混凝土边框组合剪力墙是一种适用于高层及超高层建筑的新型组合剪力墙,轴压比是影响剪力墙受力性能的一个主要因素,设计了5个具有不同轴压比的试件,进行了有限元分析,研究表明随着轴压比的增大,钢管混凝土边框组合剪力墙的延性逐渐降低,屈服荷载也逐渐减小。     

钢管混凝土柱、钢筋混凝土板、钢梁连接节点的抗震性能:节点模型

基于已有试验和数值计算结果,研究了钢管混凝土柱(CFST)和钢梁的复合节点模型。采用参数研究法利用有限元分析方法(FEA)分析了节点连接处的弹性剪切刚度和剪切变形,给出了复合节点连接处包含弹性剪切刚度、剪切强度、剪切变形和滞后准则的迟滞模型。该迟滞模型用于整合基于纤维的节点宏单元,节点宏单元通过有限元方法和试验结果得到证实。研究了CFST节点和宏单元框架的整体和局部性能。该模型计算精确,建模方法适当,能够用于大尺寸和复杂组合结构的抗震性能分析。     

Ultimate strength of dented steel plates under edge shear loads

The aims of this paper are to investigate the ultimate shear strength reduction characteristics of steel plates due to local impacts, and also to develop the ultimate shear strength design formulae of dented steel plates. The ANSYS nonlinear finite element code is used to investigate the effects of shape, size (depth, diameter), and location of the denting on the ultimate strength behavior of simply supported steel plates under edge shear loads. A closed-form expression for predicting the ultimate shear strength of dented steel plates is derived by the regression analysis based on the computed results. The results and insights developed from the present study will be very useful for damage tolerant design of steel plated structures with local denting.     

Seismic performance of CFST column to steel beam joint with RC slab: Joint model

Based on the previous experimental and numerical investigations presented in Han and Li (2010)and Li and Han (2011), this paper studies the joint model for the composite joint consisted of circular concrete filled steel tubular (CFST) column and steel beam with external diaphragm. The elastic shear stiffness and the shear deformation of the joint panel zone are investigated by parametric study using the finite element analysis (FEA) model. A hysteretic model incorporating the shear stiffness, shear strength, shear deformation and the hysteretic rules is proposed for the panel zone of the composite joint. This hysteretic model is then integrated in a fiber-based joint macro element. The joint macro element is validated by both FEA and experimental results. The overall and the local behavior of CFST joints and frame with macro elements are investigated. The proposed model is featured with a favorable accuracy and amenable modeling method, and could be applied to simulate the seismic behavior of large-scale and complex composite structural systems.     

Practical nonlinear analysis of steel–concrete composite frames using fiber–hinge method

A fiber–hinge beam–column element considering geometric and material nonlinearities is proposed for modeling steel–concrete composite structures. The second-order effects are taken into account in deriving the formulation of the element by the use of the stability functions. To simulate the inelastic behavior based on the concentrated plasticity approximation, the proposed element is divided into two end fiber–hinge segments and an interior elastic segment. The static condensation method is applied so that the element comprising of three segments is treated as one general element with twelve degrees of freedom. The mid-length cross-section of the end fiber segment is divided into many fibers of which the uniaxial material stress–strain relationship is monitored during analysis process. The proposed procedure is verified for accuracy and efficiency through comparisons to the results obtained by the ABAQUS structural analysis program and established results available from the literature and tests through a variety of numerical examples. The proposed procedure proves to be a reliable and efficient tool for daily use in engineering design of steel and steel–concrete composite structures.     

双钢板-混凝土组合剪力墙压弯承载力数值模型及简化计算公式

基于双钢板-混凝土组合剪力墙构件材料的单轴本构关系,研发了分析组合剪力墙压弯性能的弹塑性数值模型,对构件的弯矩-曲率曲线以及压弯相关关系曲线进行分析,并对压弯承载力进行计算,该模型计算结果与有限元分析结果、试验结果吻合良好。基于该模型对组合剪力墙中部墙体承担弯矩比例进行统计,结果表明,组合剪力墙中部墙体在受弯过程中承担比例较大,设计中不可忽略。对组合剪力墙压弯承载力进行数值计算和参数分析,研究了极限状态下影响压弯承载力关键因素,并基于关键参数提出计算该类组合剪力墙极限状态压弯承载力的简化计算公式,将该简化公式计算结果与数值结果进行对比,并与文献中组合剪力墙试验进行对比验证,计算精度较高,该公式可用于双钢板-组合剪力墙压弯承载力设计。     

Shear strengthening of RC beams with web-bonded continuous steel plates

This paper presents the results of an experimental program and a parametric study conducted on RC beams strengthened in shear with web-bonded continuous steel plates. An experimental investigation was conducted to assess the effectiveness of web-bonded continuous steel plates for shear strengthening of RC beams having internal stirrups. A two-dimensional nonlinear finite element model was developed to simulate the overall behavior of beams with epoxy bonded steel plates. In order to develop a design methodology for beams with web-bonded steel plates, a parametric study was conducted. Main parameters considered were concrete strength, plate thickness, plate depth-to-beam depth ratio, yield strength of steel plates, beam size and the internal shear reinforcement ratio. A formula to compute the shear strength of such beams was proposed by adding up the concrete contribution, shear reinforcement contribution and the contribution of steel plates. The validity of proposed formula was checked against the results from parametric study and the experiments. It was found that the proposed formula predicts the ultimate shear strength of RC beams with web-bonded continuous steel plates very well.     

Behaviour of embedded steel plate in composite coupling beams

Plate-reinforced composite (PRC) coupling beam is fabricated by embedding a vertical steel plate into a conventional-reinforced concrete coupling beam to enhance its strength and ductility. Shear studs are welded on the steel plate surfaces to allow for proper load transfer between the concrete and steel plate. The present study focuses on the evaluation of internal load distributions and load sharing on the embedded steel plate as well as at the shear studs in composite coupling beams using the nonlinear finite element package ATENA. The proposed two-dimensional finite element model is able to simulate the overall load-deflection behaviour and internal load distributions of coupling beams subjected to bending and shear forces. The reliability of the model is demonstrated by comparisons with the available experimental results. This is followed by an extensive and carefully planned parametric study using the calibrated finite element model. Numerical results on the effects of steel plate geometry, span-depth ratio of beams and steel reinforcement ratios at beam spans and in wall regions are presented and discussed in this paper. The finite element model provides a better understanding of the behaviour of shear studs as well as plate anchorage in the wall regions and embedded beam region. Based on the numerical results, equations for quantifying the shear stud forces are established and a set of non-dimensional design charts for determining the internal forces of the embedded steel plates is constructed. Both of them are useful for engineers to design PRC coupling beams.     

Inelastic behaviors of steel shear tab connections

Inelastic behaviors of shear tab connections commonly used in modern steel buildings are investigated in this work. Full‐scale steel shear tab connections with and without concrete slab physically tested by other researchers are closely simulated by non‐linear finite element (FE) method. Different nonlinear FE features (inelastic materials, surface‐based contacts and large geometric options) are included, and different solution strategies (Newton method and Explicit Dynamic method) are employed to balance computational effort and solution accuracy. The simulations extend our understandings on shear tab connections at micro levels, including stress distribution in the connection zone, movement of the neutral axis along the beam sections and normal stress distributions along steel shear tabs and concrete slabs. It is found that the shear tabs contribute to flexural strength of the beam‐to‐column connection and the elastic–plastic theory explains the observed behavior well only when concrete slab is not present. The composite steel shear tab connections have unsymmetrical behavior under negative and positive bending moments. The compressive concrete slabs significantly increase the flexural stiffness and strength of composite shear tab connections. It is also verified that the shear studs near steel columns play a key role for the composite connections. Copyright © 2013 John Wiley & Sons, Ltd.