Experimental study on seismic behaviors of steel-concrete composite frames

Steel-concrete composite frames are seeing increased use in earthquake region because of their excellent structural characteristics, including high strength, stiffness, and good ductility. However, there exist gaps in the knowledge of seismic behavior and the design provisions for these structures. In order to better understand the seismic behaviors of composite frame systems, eight steel-concrete composite frames were designed. These composite frames were composed of steel-concrete composite beams and concrete filled steel tube columns. The axial compression ratio of column, slenderness ratio and linear stiffness ratio of beam to column were selected as main design parameters. The low reversed cyclic loading tests of composite frame system were carried out. Based on test results, the seismic behaviors of composite frames such as failure mode, hysteresis curve, strength degradation, rigidity degradation, ductility and energy dissipation were studied. Known from the test phenomenon, the main cause of damage is the out-of-plane deformation of steel beam and the yielding destruction of column heel. The hysteretic loops of composite frame appear a spindle shape and no obvious pinch phenomenon. The results demonstrate that this type of composite frame has favorable seismic behaviors. Furthermore, the effects of design parameters on seismic behaviors were also discussed. The results of the experiment show that the different design parameter has different influence rule on seismic behaviors of composite frame.     

有侧移半刚性连接组合框架柱的稳定分析

为了研究有侧移半刚性连接组合框架的稳定性能,利用三柱子框架模型,考虑了梁端和柱远端不同约束情况对柱有效长度系数的影响,提出柱有效长度系数的简化方法.通过算例研究了节点的非线性弯矩-转角关系和荷载水平大小对柱有效长度系数的影响,比较了简化方法、Barakat-Chen方法与精确方法的计算结果.研究表明:简化方法比Barakat-Chen方法有更好的精确度,与精确方法计算结果接近.     

预应力钢-混凝土施加预应力时的滑移效应分析

报道了9个预应力钢--混凝土组合梁在负弯矩区混凝土受拉翼缘施加预应力的模拟试验结果,对此阶段预应力钢--混凝土组合梁的工作性能、钢-混凝土界面滑移规律及主要影响因素进行了较深入研究,建立了相应的界面滑移经验计算公式,并与有限元结果进行了比较.     

单层单跨组合梁钢框架刚度的分析

为研究竖向荷载作用下单层单跨组合梁钢框架的刚度,将组合梁钢框架中的梁简化为阶梯形变截面梁,进行参数确定;应用试验值验证ANSYS有限元程序分析组合梁钢框架的可行性,利用此程序进行组合梁钢框架的非线性分析,确定了组合梁钢框架在竖向荷载作用下的负弯矩区长度参数,从而建立了该组合梁刚度计算模型.采用等效原理,确定出竖向荷载作用下单层单跨组合梁钢框架的等效刚度计算公式,给出工程设计时刚度取值的建议,并与有限元分析结果进行了对比.结果表明:理论分析和推导与ANSYS有限元分析结果吻合很好.     

预应力钢-混凝土组合梁抗震性能试验研究

对普通钢-混凝土组合梁的钢梁和混凝土板施加预应力,即形成了预应力钢-混凝土组合梁.基于5根梁的低周反复荷载试验,对预应力钢-混凝土组合梁的破坏形态、滞回曲线、变形恢复能力、延性、耗能能力、刚度退化等抗震性能进行了较为系统的研究,重点探讨了预应力度和剪力连接程度对其抗震性能的影响.研究表明,预应力钢-混凝土组合梁具有良好的抗震性能.     

T形截面钢-混凝土组合异形柱抗震性能试验研究

为研究T形截面钢-混凝土组合异形柱的抗震性能,对4根不同配钢形式和轴压比试件进行低周反复荷载试验.基于实测的滞回曲线和破坏形态,分析配钢形式、轴压比对滞回特性、骨架曲线、延性、刚度退化和耗能性能的影响.研究表明:试件均发生弯曲破坏;配钢形式为T形钢+方钢管试件较实腹式试件除承载力略低外其他抗震性能指标均较好;轴压比较大时,试件承载能力提高,达到极限承载力后刚度退化较快,延性降低;型钢的加入使钢-混凝土组合异形柱的承载能力、变形能力及延性明显提高.     

钢梁-角钢混凝土柱组合框架地震反应分析

基于S－SC组合框架的试验研究建立了结构模型和恢复力模型，采用分段变刚度单元模型编制弹塑性动力学分析程序，进行该类组合框架的整体地震反应分析，研究了不同地震波的加速度及频谱特征对结构反应的影响。     

钢-混凝土组合巨型框架柱抗震研究进展

为促进钢-混凝土组合柱在超高层巨型框架结构中应用,在简要介绍采用钢-混凝土组合巨型柱的巨型框架结构基础上,从型钢混凝土巨型柱和钢管混凝土巨型柱两个方面综述了钢-混凝土组合巨型柱抗震关键技术研究及应用,指出了该类钢-混凝土组合巨型柱若干有待深化研究的技术问题.分析表明:巨型框架结构是一种受力性能优越的高效抗震体系,中国已建成和在建的标志性超高层建筑大多采用了钢-混凝土组合巨型柱框架结构,相关研究主要集中在弹塑性有限元分析和模拟地震振动台方面;复杂截面钢-混凝土组合巨型柱,经合理设计后具有较好的抗震性能,具有普适性的受力性能理论计算方法及合理抗震构造是亟待深化研究的关键技术问题.     

钢框架结构地震响应分析研究

以二阶弹性分析方法理论为基础,建立了非线性二阶微分方程,按照输入不同地震波维数和阻尼比两种情况分析了钢框架结构的地震响应.利用MIDAS软件对结构进行多遇地震作用下的弹性时程分析和罕遇地震作用下的弹塑性时程分析,表明地震波输入维数(单向地震波和双向地震波)、阻尼比对结构的抗震性能有较大影响,并根据分析结果提出了相应的建议.     

Analysis of free vibration characteristic of steel-concrete composite box-girder considering shear lag and slip

Based on Hamilton principle,the governing differential equations and the corresponding boundary conditions of steel-concrete composite box girder with consideration of the shear lag effect meeting self equilibrated stress,shear deformation,slip,as well as rotational inertia were induced.Therefore,natural frequency equations were obtained for the boundary types,such as simple support,cantilever,continuous girder and fixed support at two ends.The ANSYS finite element solutions were compared with the analytical solutions by calculation examples and the validity of the proposed approach was verified,which also shows the correctness of longitudinal warping displacement functions.Some meaningful conclusions for engineering design were obtained.The decrease extent of each order natural frequency of the steel-concrete composite box-girder is great under action of the shear lag effect.The shear-lag effect of steel-concrete composite box girder increases when frequency order rises,and increases while span-width ratio decreases.The proposed approach provides theoretical basis for further research of free vibration characteristics of steel-concrete composite box-girder.     

钢-混凝土组合梁钢框架节点抗震性能试验

为了研究钢-混凝土组合梁钢框架节点的抗震性能,本文进行了3个1／2缩尺的钢-混凝土组合梁钢框架节点的拟静力试验,主要研究了节点类型(2个中柱节点、1个边柱节点)、混凝土板宽度等对组合节点抗震性能的影响,对节点的破坏模式、滞回曲线、耗能能力、延性、强度和刚度退化等性能进行了研究,并利用有限元软件ABAQUS对组合节点在单调荷载作用下弹塑性性能进行分析,对比可知理论分析与试验结果吻合较好．研究表明:组合节点的变形能力以及耗能能力较强,强度与刚度退化不明显,节点位置和混凝土板有效宽度对节点抗震性能影响较大．     

偏心支撑半刚性连接钢框架的动力特性研究

将偏心支撑与半刚性连接钢框架相结合是一种新型抗震结构体系,为探讨其动力特性和影响因素,进行了大型试验研究和有限元数值模态分析。结果表明：偏心支撑半刚性连接钢框架的动力特性与传统框架结构并不相同,随着梁柱节点转动刚度的降低,结构自振周期延长,阻尼比增加,我国现行规范的相关规定不适用这种结构体系。最后依据研究结果,提供了偏心支撑半刚性连接钢框架的自振周期简化计算方法和阻尼比参考值。     

Static behavior of semi-rigid thin-walled steel-concrete composite beam-to-column joints with bolted partial-depth flush end plate:experimental study

A new type of semi-rigid thin-walled steel-concrete composite beam-to-column joint has been proposed in this paper.Five semi-rigid composite beam-to-column joint specimens subjected to hogging moments under monotonic loading were tested to study the static behavior of this new type of joint.The main variable parameters for the five joint specimens were the longitudinal reinforcement ratio and the joint type.The experimental results designated that the magnitude of extension of the longitudinal reinforcement is the most important factor that influenced the moment-rotation characteristic of the new type of joint.The concrete slabs could resist 3.8%-19.1% of the total shear load applied to the cross-sections near the beam-to-column connection.The edge stiffened elements,such as the flange of the lipped I-section thin-walled steel beam,were capable of having considerable inelastic deformation capacity although they had comparatively large width-to-thickness ratios.The shear failure of the concrete cantilever edge strip must be taken into account in practical design because it has significant influence on the anchorage of the longitudinal reinforcement in the new type of external joints.     

Effects of temperature change on elastic behavior of steel beams with semi-rigid connections

Based on the nonlinear displacement-strain relationship, the virtual work principle method was used to establish the nonlinear equilibrium equations of steel beams with semi-rigid connections under vertical uniform loads and temperature change. Considering the non-uniform temperature distribution across the thickness of beams, the formulas for stresses and vertical displacements were presented. On the basis of a flowchart for analysis of the numerical example, the effect of temperature change on the elastic behavior of steel beams was investigated. It is found that the maximal stress is mainly influenced by axial temperature change, and the maximal vertical displacement is principally affected by temperature gradients. And the effect of temperature gradients on the maximal vertical displacement decreases with the increase of rotational stiffness of joints. Both the maximal stress and vertical displacement decrease with the increase of rotational stiffness of joints. It can be concluded that the effects of temperature changes and rotational stiffness of joints on the elastic behavior of steel beams are significant. However, the influence of rotational stiffness becomes smaller when the rotational stiffness is larger.     

钢板与轻骨料混凝土组合梁滑移性能研究

在钢板与轻骨料混凝土组合梁中，钢板与轻骨料混凝土的交接面必产生相对滑移，这种滑移是影响组合梁受力性能的一个重要因素，可降低组合梁的承载力，增加组合梁的变形．通过5根钢板与轻骨料混凝土组合梁的试验研究，分析了钢板与轻骨料混凝土组合梁的交接面滑移性能，利用弹性理论，建立其交接面相对滑移微分方程，得到不同工况下的钢板与轻骨料混凝土组合梁滑移计算公式。并通过试验对其进行验证，理论计算结果与试验结果吻合良好．     

钢-混凝土组合梁截面刚度的分析

建立了考虑钢梁与混凝土板之间的滑移效应以及截面的塑性发展对钢-混凝土组合梁截面刚度影响的组合梁刚度计算模型,进行了理论推导.应用偏心板单元和偏心连接单元编制了钢-混凝土组合梁非线性有限元分析程序NACB2.0,利用NACB2.0及ANSYS进行了组合梁非线性分析,计算了组合梁在各级荷载下的挠度值,确定了组合梁的弹性截面刚度和塑性截面刚度,得出了截面刚度计算公式,并与规范中的换算截面法和现有的试验结果进行了对比.结果表明:滑移效应及塑性发展在一定程度上使组合梁的截面刚度比按照换算截面得到的刚度低,不可忽略;理论分析和推导与试验结果吻合很好.     

端部带拉筋方钢管混凝土柱-钢混凝土组合梁框架结构抗震性能试验研究

“柱铰”是造成结构垮塌的主要因素。采取必要的结构构造措施在不增大结构刚度的基础上避免“柱铰”的形成是一个亟待思考与解决的课题。为提高钢管混凝土组合框架结构在地震荷载作用下的抗震性能,提出了一种柱端带拉筋方钢管混凝土柱-钢混凝土组合梁框架结构体系。通过对普通及端部带拉筋方钢管混凝土组合平面框架结构进行水平低周反复荷载试验,研究了柱端拉筋与梁柱抗弯承载力比对组合框架结构滞回性能、变形能力和破坏模式的影响。研究结果表明：两类组合框架结构均具有较好的抗震性能和耗能能力;试件的破坏模式主要有钢管局部屈曲、混凝土板开裂和钢管撕裂等;端部带拉筋方钢管混凝土组合框架结构的承载力与耗能能力优于普通方钢管混凝土组合框架结构;柱端拉筋能延缓结构塑性铰的出现,提高结构抗震耗能性。研究成果可为钢-混组合结构体系在抗震设防高烈度地区和城市人口密集区域的推广应用提供参考。     

带楼板梁柱强组合件抗震性能试验研究

通过一按照现行中国规范中“强节点”原则设计的高层框架-剪力墙结构中提取出的3个不同位置的梁-柱节点缩尺模型的拟静力试验,研究框架结构中不同位置梁-柱节点的抗震性能,试验采用柱端加载,同时考虑了楼板对节点抗震性能的影响,分析其延性、刚度、承载力、耗能等性能指标,并对裂缝开展情况做了详细记录,与构件的力学指标进行比对,将损...     

钢-混凝土组合梁静动力响应

为了准确分析钢-混凝土组合梁的静力和动力响应,基于接触理论和有限单元法的基本思想,提出了组合梁单元的合理位移函数,推导了考虑剪切滑移效应的组合梁单元刚度方程,并结合动力学经典理论,给出了组合梁无阻尼状态下考虑交界面剪切滑移效应的各阶自振频率和振型计算方法。通过具体算例分析了钢-混凝土简支组合梁在竖向荷载作用下的挠度和交界面的剪切滑移应变差沿梁长的分布形态,并与试验结果进行了对比,结果表明:有限元解与试验结果基本一致,说明该有限元解是合理、可信的。利用上述刚度矩阵,基于经典动力学理论,计算了组合梁在考虑剪切滑移效应时的频率和振型,并与完全相互作用的结果进行了对比分析,说明在进行动力响应计算时应考虑剪切滑移的影响,为实际工程的设计提供了一种可靠的理论计算方法。