Effects of interface slip and semi-rigid joint on elastic seismic response of steel-concrete composite frames

The stiffness matrix of semi-rigidly connected composite beams considering interface slip was established and the calculation method for elastic seismic response of composite frame was derived.The corresponding calculation programs were developed.Introducing the dimensionless quantities that were related to the connector shearing stiffness and the joint rotation stiffness,the influences of interface slip and semi-rigid joint on composite frame were transferred to quantitative parameter analysis,taking account of cross sectional properties,materials and linear stiffness of composite beam synthetically.Based on the calculation programs,free vibration frequencies and seismic responses of semi-rigid joint steel-concrete composite frame considering interface slip were calculated.The influences of interface slip and semi rigid joint on dynamic characteristics and seismic response were analyzed and the seismic design advices were presented.The results show that the interface slip decreases the free vibration frequencies and increase the seismic responses of composite frame.The semi-rigid joint reduces the free vibration frequencies and increases seismic responses of composite frame compared with rigid joint.With the increase of joint rotational stiffness,the elastic seismic responses of composite frame increase firstly and then decrease.The effects are related to the ratio of joint rotation stiffness to linear stiffness of composite beam.

Design of the Composite Steel-Glass Beams with Semi-Rigid Polymer Adhesive Joint

New and high transparent structural element, steel-glass composite beam was developed in respect to fabrication, static-structural and architectural criteria and consists of steel flanges and glass web assembled together by semi-rigid polymer adhesive, which is the key element of whole composite system. These beams can be used mainly as members of high transparent roof or floor structure as well as stiffening fins for large area glass facades. This paper deals with experimental research performed at CTU （Czech Technical University） Prague, which started by adhesive selection and initial material tests by ISO527, continued via small-scale steel-glass connection tests and graduated by full-scale tests of hybrid beams with the span of 4 m. Generalized results of these experiments, analytical and numerical studies serve as device, how to accurately predict the behavior of the beam, describe the stress distribution along the cross section and safely and economically design such a kind of structure with semi-rigid shear connection, made by polymer adhesive.

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.

Application of Modern Wood Product Glulam in Timber Frame With Tenon- Mortise Joints and Its Structural Behavior

Tenon-mortise joint is widely used in traditional timber structures around the world.This paper summarizes the results of an experimental study of the structural behavior of tenon-mortise joints made with glulam and CNC technology instead of traditional material and manual work.30 full-scale tenonmortise joints were manufactured and tested under monotonic loading,and the effects of dimension,shape,processing error and adhesive were evaluated.It was found that the round rectangular shaped tenon-mortise joints were comparable with traditional joints in terms of structural performance,but were time and labor saving.The variability of the proposed tenon-mortise joints was lower,which would benefit the design value.Applying adhesive between tenon and mortise increased the average stiffness by 4.3 times and average moment capacity by 27.4%,respectively.The gaps between wood members had little effect on the capacity and stiffness in monotonic bending but may influence the energy dissipation ability in cyclic bending.This study showed the feasibility of combining the traditional joinery method with modern wood products and manufacturing technology,which may promote the application of tenon-mortise joints in modern timber structures.

垫板对平齐式端板连接梁柱节点性能的影响

分别采用ANSYS有限元分析软件和Eurocode 3中的组件法对加入垫板的平齐式端板连接梁柱节点进行了模拟,并将模拟结果与试验结果进行了对比。结果表明:有限元分析所得的弯矩-相对转角曲线以及滞回曲线与试验结果基本吻合,节点的变形也与试验中观察到的变形一致,有限元分析可以很好地模拟此类节点的转动能力和刚度变化;采用组件法计算平齐式端板连接梁柱节点的刚度具有令人满意的精度;垫板的加入对节点整体性能没有太大的影响。

考虑楼板刚度贡献的梁柱节点半刚性连接弯矩-转角神经网络模型

首先对已有钢结构梁柱节点半刚性连接弯矩-转角经典模型存在的不足进行了述评;然后采用非线性有限元方法对有无楼板刚度贡献的外伸端板半刚性连接节点进行了非线性仿真分析,把获得的这种节点半刚性连接弯矩-转角关系与常用梁柱节点半刚性连接弯矩-转角经典模型进行了对比分析;最后运用神经网络智能算法,首次提出了考虑楼板刚度影响的十参数梁柱节点外伸端板半刚性连接智能模型。研究结果表明:楼板的存在增大了梁柱节点刚度,减少了节点相对转动,使得实际工程中存在楼板刚度影响的半刚性连接弯矩-转角关系与现有半刚性连接弯矩-转角模型计算得到的弯矩-转角关系存在着较大误差;提出的十参数半刚性连接弯矩-转角神经网络模型能较好地模拟这种节点实际受力和变形情况;提出的智能模型具有较高精度和计算效率,同时也具有可靠性、有效性和实用性。研究结果可为考虑楼板刚度贡献的其他半刚性连接形式的弯矩-转角关系的进一步研究以及在实际工程中的应用提供参考。

半刚性端板连接节点在高温下的非线性有限元分析

应用ANSYS软件获得了门式刚架半刚性端板连接节点在高温下的转角—温度关系曲线及其临界温度,探讨了端板厚度、高强度螺栓规格、加劲肋厚度、摩擦系数、端板摆放位置等组件的变化对临界温度和节点转角一温度关系曲线的影响.为了提高半刚性梁柱连接节点的抗火性能,节点各组件的尺寸或规格需要相互匹配,以免某个组件过早屈服或断裂而导致连接节点失效,特别要注意端板、柱内侧翼缘、螺栓直径之间的匹配.

外伸端板型半刚性钢节点的有限元分析

利用有限元分析软件ANSYS对外伸端板型半刚性钢节点进行了弹塑性有限元计算,分析了节点中端板厚度及螺栓直径对钢节点初始转动刚度、弹性极限弯矩和转角及塑性极限弯矩和转角的影响,从而提供了一些在外伸端板钢节点设计时值得思考的问题.

端板型半刚性组合节点的有限元分析

利用有限元分析软件ANSYS对端板型半刚性组合节点进行了弹塑性有限元计算,分析了组合节点中混凝土板中的纵向钢筋总面积及钢筋强度对组合节点初始转动刚度、弹性极限弯矩和转角及塑性极限弯矩和转角的影响,从而为这种节点的设计提供了参考和借鉴。

混凝土翼板外伸锚固对梁柱端板连接半刚性组合边节点初始转动刚度影响的模型研究

为了研究混凝土翼板外伸锚固对梁柱端板连接半刚性组合边节点初始转动刚度的影响,运用组件法和弹塑性理论提出了混凝土翼板外伸锚固对梁柱端板连接半刚性组合边节点初始转动刚度影响的计算公式,通过与试验结果对比表明:计算值与试验值吻合较好。因此,该计算公式可用于梁柱端板连接半刚性组合边节点刚性的判断和参数研究。

锚固对梁柱端板连接半刚性组合边节点力学性能影响的试验研究

为了研究混凝土翼板外伸锚固的梁柱端板连接半刚性组合边节点力学性能,设计了3个足尺试件,其中两个混凝土翼板外伸150mm,厚度分别为140mm和200mm;另外一个为混凝土翼板未外伸的对比试件。采用柱顶水平位移控制低周循环加载试验,分析了锚固对该半刚性组合边节点力学性能的影响。结果表明,混凝土翼板外伸锚固(尤其是外伸锚固部分加厚)能够提高该半刚性组合边节点的稳定性及其抗震能力。因此,在实际施工中,应该尽可能锚固。

门式刚架节点刚度的再探讨

对轻型门式刚架几种不同型式的端板-螺栓连接节点的刚度进行分析,并提出相应的计算方法。节点型式包括设置在边柱顶部的端板连接,斜置的端板连接和设置在中柱顶部的连接。还提出个别节点达不到刚性节点要求时必须考虑其对框架稳定的不利影响。

框架梁柱平端板连接组合节点性能研究

对钢框架梁柱平端板连接组合节点进行了三维有限元模拟并用试验结果验证,进而对不同参数进行了分析,探讨了端板厚度、钢筋、螺栓、节点形式等对组合节点工作性能的影响。

梁柱齐平端板半刚性节点力学性能研究

为研究对齐平端板半刚性节点的力学性能,在试验的基础上,运用有限元软件ANSYS对典型截面半刚性节点进行静力及循环荷载加载分析,并通过改变柱翼缘、连接端板厚度和螺栓排列方式,以及增加节点域加劲肋,研究其对节点所受弯矩与梁柱相对转角曲线(M-θ曲线)的影响。有限元计算结果表明:在静力荷载作用下,M-θ曲线初期以线性关系变化,柱翼缘发生屈服后,节点表现明显的非线性特征;在循环荷载作用下,节点破坏时柱翼缘应力深入节点域发展,导致节点刚度逐渐退化,使得滞回曲线饱满,表明该节点具有较好的抗震特性。参数化分析结果表明:连接端板厚度对节点力学性能影响不大;增加柱翼缘厚度或者增设节点域加劲肋,均能显著提高节点的极限承载能力;适当减小螺栓边距能够有效提高节点的初始转动刚度和抗弯承载力。

半刚性端板连接的有限元模拟

所有的钢结构连接,是介于刚接和理想铰接之间的一种连接。而端板连接是一种典型的半刚性连接。通过对端板连接的有限元模拟,研究端板厚度等因素对节点性能的影响,为设计的合理性提供一些参考。

Modeling of semi-rigid beam-to-column steel joints under extreme loading

Joints play an important role in providing ductility for steel-composite structures subject to extreme loading conditions,such as blast,fire and impact.Due to sound energy dissipation capability and fabrication efficiency,semi-rigid joints have increasingly received attention during the last decade.This paper presents a component approach for modeling semi-rigid beam-to-column joints based on Eurocode3,where the post-elastic response,including component strain hardening and ultimate rotational capacity,is also considered.Failure criteria are defined based on the ultimate deformation capacity of components and bolt-rows.The model enables a direct integration of joint response into global frame models with the consideration of axial deformability,such that the interaction between bending moment and axial force within the joints can be realistically captured.In addition,elevated temperature can be considered in the joint model via the degradation of the component response.Through comparisons with available test data,the joint model is shown to have good accuracy,and the failure criteria are found to be reliable yet conservative.The strain hardening response of components is shown to have significant influence on the ultimate bending capacity of the joints,while neglecting it usually leads to a conservative prediction.

外伸端板连接节点抗连续倒塌性能研究

基于ANSYS有限元分析软件,建立了外伸端板连接节点模型,分析了半刚性节点在连续倒塌中的力学性能,基于该模型进行了外伸端板连接节点抗连续倒塌能力影响因素的参数分析,为相关设计提供参考。

某工程多跨门式刚架梁柱端板式连接节点的设计

CECS 102∶2002《门式刚架轻型房屋钢结构技术规程》(2012版)增加了7.2.21款条文,要求对轻型门式刚架梁柱端板式连接节点,按理想刚接进行设计。该规程针对单跨门式刚架和中柱为摇摆柱的多跨刚架的情况作了详细说明,但在很多情况下,中柱为非摇摆柱的多跨轻型门式刚架常被采用。采用CECS 102∶2002(2012版)和欧洲规范规定的准则,结合合肥某工程多跨轻型门式刚架,验算了中柱、边柱与横梁连接的受力和节点整体转动刚度。结果表明:中柱与横梁的连接节点较难满足理想刚接的要求,为保证刚架安全,应严格按照规程7.2.21款设计刚架边柱节点。利用MIDAS GEN程序验算了中柱与横梁连接节点不同相对刚度下的刚架内力和变形,发现其对内力的影响较小,对柱顶水平位移的影响较大。本工程按照MIDAS的计算结果,忽略中柱节点半刚性对刚架内力的影响,仅对柱顶水平位移进行修正。

一种半刚性连接的四面体单元球形端板式节点及力学性能分析

六杆四面体单元组成的各种空间网壳是一类结构构造简单,受力性能优越的空间结构形式,其节点可根据整体结构力学性能的不同要求采用多种不同的连接方式。目前,针对六杆四面体单元所组成的各种形体的网壳及不同的节点连接方式已展开了较为系统的理论分析和模型试验研究,但对节点的构造做法研究还相对较少。在六杆四面体单元组成的球面网壳基础上提出了一种可装配的半刚性连接球形端板式节点,采用通用有限元分析软件Abaqus建立了精细化有限元节点模型并进行了数值模拟分析,分析结果表明:该节点可应用于满足装配要求的弦杆刚接、腹杆铰接的由六杆四面体单元组成的球型网壳,且节点受力性能优越,可满足实际工程的需要。

垫板对端板连接半刚性组合边节点力学性能影响的实验研究

为了研究钢框架梁端板与柱翼缘间加设垫板的端板连接半刚性组合边节点力学性能,设计4个足尺试件,其中3个分别加设了厚度为6mm、9mm、12mm的垫板,另外一个为未加设垫板的对比试件。该文采用柱顶水平位移控制低周循环加载试验,分析了垫板对端板连接半刚性组合边节点力学性能的影响。结果表明:当垫板厚度小于端板厚度时,垫板的影响较小;当垫板厚度接近或大于端板厚度时,垫板的影响比较明显。因此,在实际施工中,应该尽可能避免加入较厚的垫板。