带楼板的钢梁和CFT柱抗弯连接的抗震分析

对4个带楼板的钢管混凝土柱连接进行抗震性能分析,包括2个内部和2个外部节点。研究目的主要是对台湾地区广泛采用的钢梁组合楼板的性能进行分析。其次对梁末端楔形翼缘或者较大剪切键等连接处的抗震性能也进行了研究,以避免如Northridge地震后出现的那种不可预料的脆性破坏导致的梁翼缘焊缝完全熔透。     

Seismic behavior of steel beam and reinforced concrete column connections

This paper aims to investigate the seismic behavior of steel beam to reinforced concrete column connections with or without the floor slab, acting as a proof test for a three-story-three-bay reinforced concrete column and steel beam (RCS) in-plane frame tested at the National Center for Research on Earthquake Engineering (NCREE), Taiwan, by the Taiwan-USA international research cooperation group. In total, six cruciform RCS joint sub-assemblages were constructed and tested. Parameters considered included composite effects of the slab and beam, the tie configuration in the panel zone, effects of the cross-beam, and the loading protocol. Force-deformation behavior was also simulated by a nonlinear analysis program, DRAIN-2DX, with consideration of composite effects of the beam and slab as well as shear distortion in the panel zone. Test results showed that all specimens performed in a ductile manner with plastic hinges formed in the beam ends near the column face. It was found that the ultimate strength of the composite beam was increased by 27% on average, compared with that of the steel beam without the slab.     

新型配式混凝土楼盖π式板缝连接节点抗剪性能研究

为研究新型全装配混凝土楼盖π式板缝节点的平面内抗剪性能,进行了π式板缝节点单调和低周反复荷载下的足尺试验,对π式板缝节点的破坏过程及形态、荷载-变形曲线和耗能能力等进行了系统研究。结果表明:两种荷载模式下,π式板缝连接节点均发生了锚筋与锚板间的焊缝破坏,抗剪承载力较低;节点滞回曲线捏拢现象较为严重、耗能能力和抗震性能较差;建议采用穿孔塞焊等方法来保证π式连接件锚筋与锚板T形焊的焊接质量,提高其抗剪能力。     

组合网架结构抗剪连接设计

组合网架是由混凝土楼板、钢网架和抗剪连接件组成的空间结构.抗剪连接件是组合网架上下两部分共同工作的基础,而在现有规范中,并没有对其设计做出明确规定.本文在探讨了现浇楼板和钢网架接触面上的剪力分布规律并据其提出抗剪连接设计准则的基础上,利用有限元法和等代空间桁架分析法分别推导出了接触面剪力计算公式,并通过数值解和实测值的...     

冷弯薄壁型钢组合楼盖和自攻螺钉连接的抗剪性能试验研究

对3个足尺冷弯薄壁型钢楼盖试件的面内受力性能进行了水平低周往复加载试验研究,得到其破坏特征、承载力指标以及自攻螺钉连接的破坏模式,试验结果表明C形边梁与压型钢板间的自攻螺钉连接破坏导致了楼盖试件破坏。基于楼盖试件面内破坏现象,对C形楼盖梁与U形边梁间、C形楼盖梁与压型钢板间两种自攻螺钉连接形式进行了抗剪性能试验研究,得到自攻螺钉连接的破坏形态和单颗自攻螺钉的抗剪承载力,分析了中国规范GB 50018-2002对于计算单颗自攻螺钉抗剪承载力的适用性。采用基于性能的抗震设计理论对冷弯薄壁型钢楼盖中自攻螺钉连接的性能水平、性能目标以及承载力指标进行了探讨,其结果可用于指导冷弯薄壁型钢结构体系的抗震设计。     

Development of interlocking mechanism for shear transfer in composite floor

Semi-pre-cast floor slab (called half slab in Malaysia) has been used widely in different parts of the world. It consists of a reinforced concrete pre-cast layer that acts initially as a formwork connected in situ with another concrete layer using shear connectors. Steel reinforcement (shear link, studs and/or steel truss) is commonly used to transfer the horizontal shear between the two composite layers. Longitudinal shear failure is the most common type of failure in the composite floor slab. This paper proposes a new system to transfer the horizontal shear between the interfaces of the pre-cast and cast in situ layers of concrete slab. The proposed system implements an interlocking concept and does not require any shear reinforcement. The composite floor slab used to illustrate the interlocking concept consists of a pre-cast inverted ferrocement layer interconnected with the cast in situ brick–mortar layer. The effectiveness of the interlocking mechanism in transferring the stresses developed due to the applied load is investigated. Eleven composite slab specimens having different shear connectors between the two layers were cast and tested under pure shear loading (push-off test). In the tested specimens, different interlocking mechanisms, continuous truss shear connectors and no connectivity between the two layers were used to connect the layers of slabs. The results indicate that the interlocking mechanism proposed is, as effective as, the steel trusses in resisting shear stresses and can be used to replace the steel trusses, which in turn will reduce the cost of the composite slab.     

中空夹层钢管混凝土柱与钢-混凝土组合梁节点抗震性能试验研究

以中空夹层钢管混凝土柱与带钢筋混凝土楼板的钢-混凝土组合梁采用高强螺栓及T形钢连接件构成的组合节点的抗震性能为研究对象,对6个十字形组合节点以梁端反对称加载的形式进行拟静力试验。试验中以柱轴压比、加劲肋、T形钢连接件尺寸、楼板厚度和楼板配筋率等为变化参数,研究该组合节点的破坏特征、滞回性能、抗剪性能、承载力衰减、刚度退化规律、耗能特性以及应变变化等力学性能。研究结果表明：柱内置钢管在增加柱受压承载力的同时可以有效增加节点核心区受剪能力,改善了节点整体受力性能;增大楼板配筋率(当1%≤ρ≤ρmax时)和减小柱轴压比(当n≤0.3时)能增强节点总耗能能力,但会降低节点延性且对节点承载力无明显提高作用;T形钢翼缘厚度和设置加劲肋对节点抗震性能影响较大。     

Seismic behavior of CFRSTC composite frames considering slab effects

This paper reports on an experimental and numerical investigation conducted on the seismic behavior of concrete-filled rectangular steel tubular columns (CFRSTC) composite frames. The experimental study was conducted by subjecting two full-scale composite frames to simulated seismic loads. Both frames were composed of CFRSTC and steel beams. One specimen was placed on a reinforce concrete (RC) floor slab and the other was not. The purpose of the test was to investigate the elasto-plastic performance of the CFRSTC composite frame system and to examine the effects of composite action on the behavior of composite frames. The test results showed that the stiffness, strength and energy-dissipating capacity of the CFRSTC frame increased significantly with the presence of the floor slab. Compared with a bare steel beam, the composite beam experienced a decrease in the rotation capacity from 0.046 rad to 0.026 rad. The shear deformation of the panel zone grew because of the composite action, which delayed the fracture of the beam. Finite element (FE) models were established to simulate the tested frames. The results of the FE model fit well with that of the test model in terms of stiffness, strength, hysteretic behavior and component deformation.     

Development of floor slab for steel post-tensioned self-centering moment frames

A floor slab constructed in conventional moment-resisting frames (MRFs) limits opening of gaps at the beam-to-column interfaces, causing losses of self-centering capability and preventing its use in steel post-tensioned (PT) moment frames. This work presents two novel slab schemes to reduce the restraints on the seismic responses of a PT frame. The first scheme uses a slab in typical MRFs with a modification so that near the connection, the metal deck is discontinuous and the longitudinal bar in the deck is debonded from concrete to minimize slab restraints. The second scheme uses truss elements to connect the slab and beams in only one bay (rigid bay) of the PT frame for transferring inertial forces from the floor to the frame. The sliding device is provided at one end of floor beams transverse to the PT frame, where sliding of the slab is expected. The cyclic behaviors of the bare connection and the connection with the first slab scheme are also evaluated by testing four connections. Additionally, how the rigid bay affects the cyclic behavior of the frame, distribution of column shear, beam axial force variation, and gap opening response near the beam-to-column interface is evaluated by conducting frame subassembly tests. The test results demonstrate that (1) the PT frame with any of two slab schemes develops large deformation capacities with small residual deformations, and (2) the column shear and beam axial force can be estimated based on the proposed method.     

楼板对钢筋混凝土柱-钢梁空间组合体抗震性能影响研究

楼板在地震作用下对钢筋混凝土柱-钢梁组合体抗震性能的影响是建立地震作用下节点计算模型的基础,也是准确评价组合结构体系抗震性能的关键问题之一。为此,完成了3个钢筋混凝土柱-钢梁(RCS)空间组合体试件在考虑不同楼板宽度情况下的抗震性能试验,分析整个受力过程中楼板受力性态对组合构件受力特征、破坏模式等抗震性能的影响。各试验模型在加载过程中均产生梁铰破坏,并表现出较好的延性和耗能能力,最终因节点区钢梁屈曲、扁钢箍开裂和柱端混凝土压碎而丧失承载力。分析表明,楼板裂缝以横向裂缝为主,随着楼板宽度增加,次生斜裂缝增多,板底混凝土压碎区域增大;混凝土楼板与钢梁组合体对节点核心区的约束作用较明显地改善了空间组合体受力性能。对楼板混凝土和板内纵筋在受力过程中的应变进行分析,结果表明,随着楼板宽度的增加,楼板对RCS空间组合体刚度、承载力的贡献值有限。对现浇板受拉有效翼缘宽度进行分析,结果表明考虑钢-混凝土组合梁翼缘有效宽度对梁端受弯承载力、惯性矩影响较大。     

型钢混凝土L形柱-混凝土梁框架节点滞回性能试验研究

为研究型钢混凝土L形柱-混凝土梁框架节点的滞回性能,以柱截面配钢形式、轴压比、水平加载角度及 有无楼板参与工作为变化参数,进行4个平面和7个空间L形柱-混凝土梁框架节点的拟静力试验;比较分析试件的 破坏形态、滞回曲线、承载能力、刚度退化、耗能能力、位移延性以及层间位移角等抗震性能指标。研究结果表 明：平面节点和空间节点的破坏形态分别为核心区发生剪切破坏和梁端出现塑性铰,带楼板工作的钢筋混凝土梁 柱空间节点出现板的弯曲破坏以及梁底出现塑性铰的破坏模式;配实腹式型钢试件的滞回曲线比配空腹式型钢试 件的饱满;平面节点的承载能力比空间节点的大,但耗能能力、位移延性及抗倒塌能力均不及空间节点;楼板的 存在对节点承载能力的提高和维持刚度的稳定均具有有利作用;轴压比可提高节点的承载力和初始刚度;L形柱 框架节点的层间变形能力大于规范规定的层间位移角限值。通过引入加载角度,提出了型钢混凝土L形柱-梁空间 节点受剪承载力计算模型,其能较好地反映节点核心发生剪切破坏的传力机制。     

预制混凝土管组合柱-钢梁连接节点抗震性能试验研究

为研究预制混凝土管组合柱-钢梁连接节点的抗震性能,以轴压比、钢套箍延伸高度、芯部混凝土强度以及钢套箍厚度为主要参数,进行了6个1/2缩尺节点的拟静力试验。研究了各节点的破坏形态、滞回特性、承载能力、耗能能力以及节点域受剪性能。试验结果表明：各节点主要破坏模式均为节点域剪切破坏;滞回曲线呈典型弓形,耗能能力较好;芯部混凝土强度和钢套箍厚度是影响节点抗震性能的关键参数,对承载能力和耗能性能影响较大;破坏时节点域极限剪切变形介于0.0482 ~0.100 rad之间;节点域受剪承载力降低系数介于0.86~1.00之间,承载力退化性能稳定。建立了预制混凝土管组合柱-钢梁连接节点受剪承载力计算式,计算值与试验值吻合较好且偏于安全。     

钢-混凝土组合框架结构体系抗震性能参数分析

为了全面研究钢-混凝土组合框架结构的抗震性能,对某典型的15层组合梁-方钢管混凝土柱框架结构进行了参数分析,讨论了方钢管混凝土柱截面含钢率、楼板厚度和组合梁钢梁高度变化对结构抗震性能的影响规律。分析结果表明:结构的周期和弹性位移反应受组合梁钢梁高度影响最为显著,含钢率的影响次之,随着钢梁高度和截面含钢率的增大,结构周期及弹性位移反应均有不同程度的降低;结构初始刚度和极限承载力受楼板厚度影响最为显著,钢梁高度影响次之,随着楼板厚度的增加和钢梁高度的增大,结构初始刚度均有不同程度的提高;结构的弹塑性位移反应受钢梁高度影响最大,钢梁高度增大,结构弹塑性位移反应明显降低。根据参数分析的研究结果,对不同的设计参数对结构抗震性能的影响有一个简单、直观的印象。在进行结构设计时,根据结构性能的具体需要,基于参数分析的结果,通过对结构参数进行有针对性的调整,从而更加快速、准确地优化结构设计。     

新型装配整体式板-钢框架结构模型振动台试验研究

为了研究新型装配整体式板-钢板剪力墙钢框架结构的抗震性能,对一个非对称体型新型装配整体式板-钢板剪力墙钢框架结构进行了1/4整体模型模拟地震振动台试验,试验得到结构在地震动作用下的加速度响应、位移响应以及应变响应;该结构能够满足抗震规范的要求,加载到罕遇地震时,混凝土板出现了局部微裂缝.不浇现浇面层的装配式整体式预制楼板与工字钢梁连接良好,新型装配整体式空心板表现出较好的抗震性能.本文分析了强烈度地震作用下结构的地震反应、破坏形态,给出了结构薄弱部位的构造设计意见,为同类结构的抗震设计提供了试验依据.     

两层钢管混凝土柱与组合梁单边螺栓端板连接框架拟动力试验研究

为揭示半刚性钢管混凝土组合框架在地震作用下的动力特性和破坏形式,对2榀两层单跨钢管混凝土柱与 组合梁单边螺栓端板连接组合框架进行拟动力试验研究。该试件的梁柱连接节点形式为平齐端板或外伸端板连接 ,组合楼板采用钢筋桁架楼承板,试验影响参数为柱截面类型和端板类型。研究了El-Centro地震波作用下结构 的加速度反应和位移响应,分析了滞回性能、刚度、延性和耗能能力等,评价了梁柱半刚性连接和楼板组合效应 对组合框架结构整体性能的影响。试验表明：半刚性钢管混凝土组合框架具有良好的抗震性能和耗能特性。在柱 截面宽度和含钢率相同条件下,采用单边高强螺栓端板连接方式,圆钢管混凝土组合框架的最大位移响应和累积 耗能比方钢管混凝土组合框架大;方钢管混凝土组合框架的水平承载力和初始刚度优于圆钢管混凝土组合框架。 研究成果将为我国装配式组合结构设计理论与应用提供科学依据。     

地震作用下平板有效宽度试验研究

基于振动台试验研究地震作用下钢筋混凝土平板结构有效宽度。主要研究转角处采用工字钢或槽钢(剪切头)剪切冲孔加固的板-柱连接件的性能。为此,建立平板的1∶2缩尺模型,平板由4种箱式钢柱支撑,承受逐步增加的模拟地震作用。试验结果表明:随着模拟地震作用强度的增加,有效宽度逐渐增加;同时,模拟地震作用造成的应变逆转使得钢筋与混凝土间粘结力减小,这将限制有限宽度的增加。此外,由于所使用的抗冲切钢材具有加固效果,有限宽度的试验结果与该文中所给公式的计算结果有着显著差异。     

设置垫板的梁柱T形件连接节点抗震性能试验研究

针对传统钢结构梁柱连接在地震中易脆性破坏,改进连接震后不易修复等问题,提出设置垫板的梁柱T形件连接构造措施。设计、制作3个不同形式的梁柱T形件连接试件,分别为未设置混凝土板的连接节点、设置混凝土板的连接节点和未设置混凝土板的传统梁柱T形件连接节点,对其进行往复荷载作用下的拟静力试验,研究试件的抗弯刚度、承载力、延性、滞回性能、耗能能力、破坏模式等。此外,更换梁下部翼缘处已破坏的T形件进行修复,并对修复后的试件进行拟静力试验。结果表明：设置垫板的T形件连接节点在往复荷载作用下具有稳定的滞回性能和良好的耗能能力;破坏试件的梁、柱均不发生屈服,转动中心位于梁端上部翼缘附近,能够保证在地震作用下梁端上部翼缘连接部位不发生破坏,并能够保护梁上混凝土楼板不发生较大的损坏;混凝土楼板的存在会提高节点正弯矩下的初始刚度和承载力,并使弯曲中性轴上移;更换梁下部翼缘处已破坏的T形件进行修复,修复后试件的滞回性能与原试件无明显差异。     

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。     

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.     

大型火电厂主厂房钢支撑-框架结构振动台试验模型

为了在振动台上实现大型复杂钢支撑-框架结构的模拟地震试验,以某现役大型火电厂主厂房结构为原型,根据结构静、动力性能等效原则,设计制作了大缩比振动台试验整体模型。采用钢板模拟钢-混凝土组合楼板,工形钢梁模拟钢桁架,小螺栓节点连接模拟高强螺栓连接等尽可能反映结构实际情况的制作方案和措施,探索了细部构造对整体模型影响的途径,为中国首次实现同类结构的抗震性能试验研究奠定了基础。