Rechenbeispiel zum Statischen Nachweis von Verbundträgern mit verformbaren,teiltragfähigen Verbundanschlüssen

Example to analyse composite beams with consideration of semi‐rigid, partial strength composite connections. In the article “Berechnung von Stahlverbundträgern – Ein Rechenmodell zur Berücksichtigung von verformbaren, teiltragfähigen Verbundanschlüssen” [1] an analysing model has been presented to calculate composite beams with the special consideration of ductile, partial strength connections. In this following article an analysing example illustrates the method. For a given composite connection the stiffness, the bending resistance and the ultimate rotation are analysed. After that the load bearing capacity at ultimate limit state (ULS) for a given composite beam with composite connection is analysed as well as the deflection at midspan at serviceability limit state (SLS).     

Bending and rotational behaviour of semi-continuous composite beams

Stresses and deflections were measured in various semi-continuous composite beams. The bending and rotational capacities of the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite frames with monotonic loadings. The effect of semi-rigid connections on the performance of composite beams with various loadings was compared with predictions and codes. The tests show that the semi-continuous composite beams are more economic and effective than the simple or continuous composite beams. The semi-rigid connections affect the bending capacities and beam deflections, so the connection behavior should be considered in the design of composite beams. Yielding analysis of the steel beam bottom flange has some influence on the deflection calculation of composite beams.     

套筒式钢管混凝土梁柱节点试验研究

利用ANSYS软件分析了套筒式钢管混凝土梁柱节点的承载性能,同时进行了采用力位移混合加载控制的节点承载力低周反复荷载试验。结果表明,套筒式节点和环板式节点的极限受弯承载力都能满足设计要求,但套筒式节点的转角较小,节点为刚性连接。在相同的轴压比下,两种形式节点的抗震性能相当。     

Untersuchungen über das Trag‐ und Dehnungsverhalten des Betongurtes bei Verbundanschlüssen

Investigations about the load bearing‐ and strain behavior of the concrete slab in the range of composite connections. Due to the rising cost pressures in the construction industry, it is particularly important to choose efficient design methods to achieve economic structures. The use of the plastic hinge theory may lead to good results within the steel and composite construction industry because cross section‐ and system reserves can almost fully used. This means for the normal composite beam a redistribution of the bending moment from the support section to the field section. This redistribution causes an increase of the rotation at the composite connection. The presented tests show the influence of the reinforcement (type of reinforcement and reinforcement ratio) to the rotation capacity of the connection. The increased rotation requirements of composite connections in the area of plastic hinges should already be take in to account at planning state.     

凹槽销栓型竹-混凝土组合梁的受弯性能

文章将混凝土与竹材组合,提出一种新型凹槽销栓型竹-混凝土组合结构,为研究凹槽销栓型竹-混凝土组合梁的受弯力学性能,对5组组合梁和1组对比竹梁进行四点弯曲试验,试验参数包括连接件间距及其数量,试验主要测试试验荷载、跨中挠度、竹梁与混凝土翼缘的应变以及竹梁与混凝土翼缘的界面相对滑移.试验结果表明,凹槽销栓型竹-混凝土组合梁...     

论抗震钢框架梁柱刚性连接的极限受弯承载力设计

梁柱刚性连接的极限承载力是保证强震作用下抗震钢框架安全性的关键要素之一。以H形截面梁柱的刚性连接为例,讨论其极限受弯承载力设计问题。首先,通过对《建筑抗震设计规范》（GB50011—2001）与欧洲规范以及日本相关规范的对比分析,指出：期望在遭受强烈地震作用下梁端截面形成塑性铰的钢框架,“规范”（GB50011—2001）的梁柱连接系数,至少不比欧洲规范的低,一般也不会低于日本规范的。对于梁截面较高或采用高强结构钢（Q345及以上级别钢）情况,甚至要高于日本规范的。同时指出,连接系数应随钢号而变化,采用定值连接系数不舍理。进而,讨论了梁端潜在塑性铰区域的长度,对于钢柱伸出短梁段的梁端梁一梁拼接,给出其避开梁端塑性区设定拼接位置的计算式。最后,建议梁柱连接极限承载力计算应计入腹板连接贡献的受弯承载力。对于混合连接（WUF—B）,腹板连接贡献的极限受弯承载力应取其焊接、高强度螺栓连接两者中的较小值,并推荐了相应的连接系数值。     

大直径钢管混凝土柱-H形钢梁节点设计研究

在传统内环板节点的基础上,提出一种适用于大直径钢管混凝土柱的梁柱节点。为了避免内环板宽度过大造成混凝土浇筑困难、用钢量较大的问题,在内环板焊接拉结钢筋,既可以减小钢材用量又便于在钢管柱内设置钢筋笼。为避免与钢梁翼缘焊接处的钢管表面发生层状撕裂,局部加大梁端翼缘宽度,并通过分析合理确定梁端扩翼宽度与扩翼角度。采用非线性有限元软件,对节点构造与应力分布、变形性能的关系进行分析。通过对比分析得到梁端的刚域长度,并对刚域长度与框架梁抗弯刚度的关系进行研究。为了验证该类节点设计的合理性,进行钢管混凝土柱-H形钢梁缩尺模型试验。有限元分析与缩尺模型试验结果表明,节点拉结钢筋可以提高内环板传力的有效性,有效减小节点区柱壁应力,当梁端扩翼宽度为1.5倍梁翼缘宽度、扩翼角度为1∶6时,节点区柱壁应力明显低于H形钢梁的应力,满足“强节点弱构件”的抗震设计理念。节点刚度对钢管混凝土柱-H形钢梁框架结构的侧向刚度影响显著,当梁端刚域长度约为钢柱直径的0.4倍时,框架梁的抗弯刚度可增加40%以上。节点抗震性能良好,可以实现“强节点弱构件”的抗震设计理念。     

矩形钢管混凝土柱-混凝土梁搭接式节点抗震性能研究

在现有钢管混凝土柱与混凝土梁连接形式基础上,提出一种新型搭接式钢管混凝土柱-混凝土梁节点,通过低周反复荷载试验和数值模拟分析,研究了节点的破坏形态、承载能力、刚度退化、延性及耗能能力等,分析了梁端纵筋和搭接牛腿翼缘的应变发展规律。结果表明:钢管混凝土柱-混凝土梁搭接式节点表现出典型的混凝土梁端塑性铰破坏模式,符合“强节点、弱构件”的抗震设防理念; 节点的滞回曲线饱满,捏缩现象较轻,刚度退化明显,强度退化较小,具有较好的延性及耗能能力; 梁纵筋及牛腿各测点中搭接牛腿端部截面应变最大,通过搭接连接方式可实现梁端弯矩和剪力的有效传递,但搭接牛腿长度不足会使节点发生锚固破坏; 在节点设计时,应保证足够的搭接长度,以实现钢筋混凝土梁纵筋在弯剪复合受力状态下锚固性能的可靠性,充分发挥节点的抗震耗能能力; 有限元计算结果与试验结果吻合良好,该模型能够准确反映节点在实际受力情况下的力学特性,所得结论可为此类新型搭接式节点工程应用提供技术支撑。     

Bending and rotational behaviour of semi-continuous composite beams

Stresses and deflections were measured in various semi-continuous composite beams. The bending and rotational capacities of the composite connections were measured in terms of beam curvatures and deflections by using two full-scale semi-rigid composite frames with monotonic loadings. The effect of semi-rigid connections on the performance of composite beams with various loadings was compared with predictions and codes. The tests show that the semi-continuous composite beams are more economic and effective than the simple or continuous composite beams. The semi-rigid connections affect the bending capacities and beam deflections, so the connection behavior should be considered in the design of composite beams. Yielding analysis of the steel beam bottom flange has some influence on the deflection calculation of composite beams. __________ Translated from J Tsinghua Univ (Sci & Tech), 2007, 47(3): 313–318 [译自: 清华大学学报(自然科学版)]     

钢-混凝土组合梁考虑界面滑移的振动模态试验研究

为研究钢与混凝土的界面滑移效应对钢 混凝土组合梁基本动力性能的影响程度和规律,进行了5根跨度3.8m的简支钢 混凝土组合梁的静载和振动模态试验,其中4根采用抗剪栓钉,剪力连接度分别为0.6、0.7、1.0和1.4,另1根采用能提供刚性抗剪连接的开孔钢板连接件。试验结果表明：在静载作用下,随剪力连接度的提高,组合梁的界面滑移减小,抗弯刚度显著增加。竖弯模态试验中,剪力连接度小于等于1.0的3根梁,其前4阶竖向弯曲模态频率与采用开孔钢板抗剪连接件的试验梁相比均有减小,最小减幅为9.8%,最大减幅达26%;剪力连接度为1.4的梁较开孔钢板连接件的试验梁,基频减小了6.1%,第2~4阶自振频率减小幅度均在10%以上,与连接度为0.6的梁相比,其基频增大了13.2%;试验梁的模态阻尼比随着剪力连接度的增大而减小。扭转模态试验中,各阶扭转模态频率差异程度在7%以内,变化规律不明显。由此可见,钢与混凝土板的界面滑移效应对组合梁竖向弯曲自振频率的影响不容忽视,在设计计算中须予以考虑。试验结果可为工程动力分析提供参考。     

Ermittlung der Grenztragfähigkeit von Mehrschraubenverbindungen bei Normalkraft‐Biegemoment‐Interaktion

Determination of the ultimate bearing capacity of multi‐bolt connections with normal force – bending moment – interaction. This paper will present a general design method for single or multi‐bolt connections of beams with arbitrary thin‐walled cross sections, suitable for application in computer programs. The design method is based on the classical strain iteration algorithm for the determination of the stress distribution in cross sections. In this case, the ultimate capacity of bolted connections will be obtained using an iterative numerical determination of the elastic‐plastic stress distribution in the connection elements. The numerical method will be derived in two steps – the first step is the numerical determination of the stress distribution in the connection for a given combination of internal forces and the next step is the determination of the ultimate bearing capacity of the connection. Furthermore, an analytical design method for a multi‐bolt tube connection will be derived. Finally, results of numerical and analytical calculations will be compared with corresponding test results.     

矩形钢管混凝土柱与钢梁半刚性节点的抗震性能试验研究

本文进行了两种矩形钢管混凝土柱与钢梁半刚性连接节点———加劲端板(SEP)连接节点与双T板(DST)连接节点在柱端低周反复荷载作用下的拟静力试验,目的在于了解这两类节点在不同轴压比下的滞回性能、强度与刚度退化、延性与破坏机制。并与常规焊接翼缘板(WFP)连接节点作了比较。结果表明:不同轴压比对节点转动有一定的影响,加劲端板(SEP)连接节点与双T板(DST)连接节点具有良好的转动延性与耗能能力。     

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.     

方钢管柱-H型钢梁槽钢连接节点受弯性能试验研究及有限元参数分析

槽钢转换件构造简单,可实现方钢管柱与H型钢梁的高效装配连接.为研究该类节点的受弯性能,完成1个竖向槽钢和3个横向槽钢连接节点受弯试验,获得节点破坏形态、受弯承载力、应变分布等性能指标;并通过有限元参数分析考察了槽钢尺寸、厚度和构造对节点受弯性能的影响规律.结果表明:槽钢连接节点均表现为半刚性,横向槽钢节点比竖向槽钢节点...     

考虑混凝土板组合效应的蜂窝钢梁柱连接抗震性能试验研究

为了研究混凝土板组合效应对蜂窝梁柱连接抗震性能的影响,对无混凝土板和有混凝土板的正六边形蜂窝梁柱连接、普通组合梁柱连接进行拟静力试验。研究混凝土板组合效应对不同开孔率的蜂窝梁柱连接的破坏形态、承载能力、刚度、延性及耗能能力的影响。试验结果表明：蜂窝梁柱连接可以有效地控制塑性铰在近柱端第一个蜂窝孔处形成,实现塑性铰外移,降低在梁柱连接焊缝处发生脆性破坏的可能性;混凝土板的组合效应可以减小蜂窝梁剪切变形的影响,与无混凝土板的蜂窝梁柱连接相比,有混凝土板的蜂窝梁柱连接的滞回曲线更饱满;混凝土板的组合效应能够提高蜂窝梁柱连接的承载能力、延性、刚度及耗能性能,开孔率越大,组合效应越显著;混凝土板组合效应降低了塑性铰区的转动能力。     

Behavior of semi‐rigid connections and semi‐rigid frames

Semi‐rigid connections are widely used in different countries. These connections are usually used in semi‐rigid frames with bracing system. Considering the frequent use of these connections, studying their behavior as an individual connection or as a frame with a semi‐rigid connection is of great importance. In this paper, moment–rotation behavior of bolted angle connection as a usual semi‐rigid connection is studied, and the affecting factors on there are investigated. Finite element connection models are developed. These models are verified by comparing the results of finite element analyses with the results of experimental test, and the verified models are used to investigate the behavior of the connections. The behavior of semi‐rigid frame with bolted angle connection is then studied conducting time‐history analyses. The results show that the increase in shear stiffness of angle bolted connections significantly decreases the lateral drift and increase the frame stability against lateral loading. Copyright © 2012 John Wiley & Sons, Ltd.     

梁端柔性对装配式框架结构的内力影响

通过采用有限单元法进行分析,研究了柔性连接对框架结构内力的影响。研究表明,在竖向荷载作用下,相比较于刚性连接,梁端弯矩和柱脚弯矩均减小,而梁跨中弯矩变大。在水平荷载作用下,相比较于刚性连接,梁端弯矩减小,底层柱脚弯矩明显增大,此时梁跨中的弯矩几乎没有变化。当水平荷载和竖向荷载共同作用时,刚性连接与柔性连接之间的内力差别也是显著的。     

美国世贸中心WTC7次梁-柱节点高温下的破坏行为分析

对美国世贸中心WTC7中采用的4种次梁-柱的钢节点建立了H型框架的有限元分析模型,模型中考虑了高层结构中常见的单根组合梁两端受到钢柱或者剪力墙等强约束的情况,对框架在自然火灾升温条件下的行为进行了分析。分析结果表明:节点是框架结构中的薄弱环节,节点的破坏往往发生在较早的阶段。比较了节点类型与特性对梁的挠度、沿梁轴向的约束力以及节点弯矩的影响,发现抗弯刚度较大的节点会产生较小的挠度和非常大的轴向约束力。对各种节点类型的破坏形式的分析发现,节点的破坏不是由于自身的强度降低,而是主要由于梁的削弱导致弯矩被转移到节点区域。如果轴向压力不对节点的受压区产生灾难性的影响,节点的破坏都发生在受拉区。因此,热膨胀引起的约束压力能减小受拉区的受力,延迟节点的破坏。     

Post-tensioned self-centering moment connections with beam bottom flange energy dissipators

This work presents results of experimental and analytical studies of self-centering moment connections. The connection subassembly consists of post-tensioned steel beams, a reinforced concrete column, and energy dissipators placed only below the beam bottom flange for simplicity of construction, ease of replacement, and no interference with the composite slab. Two types of steel energy dissipators are proposed: one includes a reduced section plate restrained by two flat plates, and the other uses cross-shaped steel plates. Cyclic tests are conducted on three full-scale post-tensioned connection subassemblies and six energy dissipators. Finite element analysis is performed to investigate the cyclic performance and likelihood of fracture at critical regions in the energy dissipators. Cyclic test results show that (1) energy dissipation, moment, and flexural stiffness of the beam in positive bending are larger than those of the beam in negative bending, (2) the location of the compression toe at the end of the beam stabilizes at the junction between the beam flange and web after an interstory drift of 1.5%, in which the gap opening angles of the beams are similar in both bending directions, and (3) the shoulder radius equal to 2.5 times plate thickness results in a premature fracture along the shape transition of the reduced section plate. This study also develops an iterative analytical procedure for predicting un-symmetrical cyclic responses of post-tensioned connection subassemblies.     

A connection element for modelling end-plate connections in fire

In this paper a robust 2-noded connection element has been developed for modelling the bolted end-plate connection between a steel beam and column at elevated temperatures. The connection element allows the element nodes to be placed at the reference plane with offset and the non-uniform temperature distributions within the connection. In this model the connection failure due to bending, axial tension, compression and vertical shear are considered. The influence of the axial tensile force of the connected beam on the connection is also taken into account. This model has the advantages of both the previous simple and component-based models. A total of 23 fire tests were used to extensively validate the model. It can be seen that the current model is robust and has a capability to predict the behaviour of a bolted end-plate connection under fire attack with reasonable accuracy. Compared to the tested results the predictions of the current model were mainly on the conservative side. Hence, the model can be used for structural fire engineering design on steel-framed composite buildings. The idea described in this paper can also easily be applied to develop other kinds of connections, such as simple connections, column based connections or hollow section connections, and so on.