空间半刚性连接钢框架有限元分析和研究

对带双腹板顶底角钢连接以及外伸端板连接空间钢框架进行了非线性有限元分析，研究了空间钢框架的静力承载性能与节点刚度的关系，得到了不同节点刚度对空间钢框架位移和内力的影响结果，对工程应用具有一定的参考价值。     

角钢厚度对半刚性梁柱连接性能影响研究

运用有限元ANSYS软件和欧洲规范EUROCODE3给出的钢材在高温环境下的热物理及力学特性参数,建立了3个不同顶底角钢厚度的带双腹板顶底角钢梁柱连接的有限元分析模型。运用热-力耦合分析方法,对双腹板顶底角钢梁柱连接在高温下的抗火性能进行了深入研究,探讨了顶底角钢厚度变化对连接在高温环境下受力机理以及螺栓预紧力受温度影响的规律,所得结果对该类节点的抗火设计具有一定的参考价值。     

双腹板角钢-顶底角钢连接半刚性梁柱节点的滞回性能模拟分析

利用ANSYS软件对双腹板角钢-顶底角钢连接半刚性梁柱节点进行了非线性有限元分析。分析考虑了几何、材料和接触非线性,获得了连接在循环荷载作用下的应力分布、塑性变形以及弯矩-转角滞回曲线,并与试验结果进行了对比。研究结果表明:双腹板角钢-顶底角钢连接梁柱节点具有稳定的滞回性能、良好的延性和耗能能力;ANSYS可用于模拟角钢连接半刚性节点的受力性能。     

半刚性连接钢框架抗震性能的模型试验研究

通过两榀1／2比例的一跨两层半刚性连接钢框架模型的低周反复荷载试验,研究了框架模型的破坏机制、、出饺顺序、滞回特性、耗能能力等抗震性能。从而得出结论：具有腹板双角钢的顶底角钢连接的钢框架由于节点连接刚度较小,因此框架在侧向力作用下变形较大,但同时此连接也改善了梁柱的内力分布,提高了框架的耗能能力,增加了结构抗震性能。     

带双腹板顶底角钢连接初始刚度研究

初始连接刚度在节点刚度分类和钢结构地震分析中占有很重要的地位,因此研究连接的初始刚度很有现实意义。主要研究带双腹板顶底角钢连接初始刚度的确定方法以及影响其性能的主要因素。     

顶底角钢连接节点的低周疲劳性能分析

本文对采用顶底角钢连接的半刚性钢梁柱连接节点进行了精细的三维非线性有限元分析,在与实验数据对比的基础上,对影响该连接性能的主要参数如角钢厚度、柱翼缘连接螺栓与梁翼缘间的距离等进行了分析,得到了其弯矩-转角曲线。     

基于性能提升的螺栓-组件连接抗倒塌分析

框架竖向承重构件失效后,节点的性能决定了荷载是否能可靠地传递给相邻构件。栓焊刚性连接具有较高的初始刚度,在大变形条件下梁端母材易过早断裂,悬链线机制的发挥无法保证;顶底角钢腹板双角钢半刚性连接虽然具有较大变形能力,但在早期小变形阶段承载力偏低,性能有所不足。为全面提高节点的抗倒塌性能,设计了1种螺栓-组件连接节点,通过建立理论模型与数值模型进行相互验证,对该连接方式的抗倒塌性能进行了细致分析。结果表明:螺栓-组件连接子结构初始阶段承载力高于栓焊连接,并且在过渡阶段稳定上升,具有较大的转动变形能力。通过将梁腹板局部加厚,可使其在大变形条件下的承载力高于双腹板顶底角钢半刚性连接,抗倒塌性能优越。该新型连接节点传力明确,各组件工作性能合理高效,理论分析表明组件约束长度β、壁厚h和滑道长度d是影响其抗倒塌性能的关键因素,并给出了设计建议。     

顶底角钢连接半刚性梁柱钢节点的滞回性能模拟分析

为了研究顶底角钢连接半刚性梁柱钢节点的滞回性能,利用ANSYS软件对该节点进行了循环荷载作用下的非线性有限元分析。分析考虑了几何、材料和接触非线性,获得了节点的应力分布、变形情况、以及连接的M-θ滞回曲线,并与试验结果进行了对比。研究结果表明:顶底角钢连接节点具有良好的延性和耗能能力;ANSYS可用于模拟角钢连接半刚性节点的受力性能。     

带顶底L型件的装配式梁柱节点试验研究

在传统半刚性节点的基础上,结合端板及顶底角钢连接,提出带顶底L型件的装配式梁柱节点,适用于变电站及多层钢框架住宅体系。分别对3个参数不同的构件节点进行循环加载试验,从耗能能力、承载力、延性及刚度退化等方面研究了该梁柱节点的抗震性能和失效模式。根据有关规范对带顶底L型件的装配式梁柱节点的弹性极限承载能力及塑性极限承载能力进行验算。结果表明,该节点主要的失效模式是梁翼缘及梁腹板发生屈曲变形和撕裂,该节点具有良好的承载力、延性、刚度及滞回性能。通过增加L型件长肢长度及L型件厚度,可改善节点在循环荷载作用下的承载力,延性及耗能能力。该节点属于半刚性节点,并满足"强柱弱梁"的要求。     

带可替换腹板连接型耗能梁段的恢复力模型研究

带可替换耗能梁段的偏心支撑钢框架具有震后修复方便、经济等优点,但目前国内外学者对该类型的研究很少。为此,设计16组与偏心支撑钢框架采用螺栓连接的腹板连接型耗能梁段,并对16组试件进行数值模拟分析,讨论截面尺寸、耗能长度、加劲肋间距、加劲肋布置以及综合参数等变化参数对腹板连接型耗能梁段在低周往复荷载作用下的滞回性能、骨架曲线的影响,建立腹板连接型耗能梁段简化的恢复力模型。结果表明,影响腹板连接型耗能梁段耗能的主要参数是截面尺寸,建立的恢复力模型与模拟的骨架曲线对比吻合较好,可以为此类耗能梁段弹塑性分析作为参考。     

铰接隅撑钢框架抗震性能研究

传统抗弯钢框架的梁柱节点通常设计为刚性连接,这种刚性节点具有很大的抗弯刚度,然而节点延性不足,罕遇地震作用导致节点脆性断裂.研究学者提出了多种解决该问题的思路,例如半刚性连接节点、节点加强或削弱方法使塑性铰外移等.本文提出了一种简化的梁柱节点连接方式-铰接连接,改变梁柱节点的传力方式,在节点处设置隅撑提供框架的抗侧刚度...     

Probabilistic evaluation of seismic performance of 3‐story 3D one‐ and two‐way steel moment‐frame structures

This paper presents the results of a probabilistic evaluation of the seismic performance of 3D steel moment‐frame structures. Two types of framing system are considered: one‐way frames typical of construction in the United States and two‐way frames typical of construction in Japan. For each framing system, four types of beam–column connections are considered: pre‐Northridge welded‐flange bolted‐web, post‐Northridge welded‐flange welded‐web, reduced‐beam‐section, and bolted‐flange‐plate connections. A suite of earthquake ground motions is used to compute the annual probability of exceedence (APE) for a series of drift demand levels and for member plastic‐rotation capacity. Results are compared for the different framing systems and connection details. It is found that the two‐way frames, which have a larger initial stiffness and strength than the one‐way frames for the same beam and column volumes, have a smaller APE for small drift demands for which members exhibit no or minimal yielding, but have a larger APE for large drift demands for which members exhibit large plastic rotations. However, the one‐way frames, which typically comprise a few seismic frames with large‐sized members that have relatively small rotation capacities, may have a larger APE for member failure. The probabilistic approach presented in this study may be used to determine the most appropriate frame configuration to meet an owner's performance objectives. Copyright © 2008 John Wiley & Sons, Ltd.     

钢框架结构的地震损伤研究

基于预定损伤法对钢框架构件主要设计参数进行损伤敏感度分析,研究主要设计参数与钢框架结构梁、柱损伤的关系;揭示钢框架结构梁、柱的损伤及梁、柱线刚度比、结构高宽比、柱轴压比、锈蚀率对楼层损伤的影响规律;获得楼层的损伤与整体结构损伤的关系,最终建立钢框架结构的损伤演化模型。研究成果可为建立地震激励下钢框架结构的损伤模型提供理论基础和数据支持。     

Experimental study on full-scale steel beam-to-column moment connections

Ten full-scale steel beam-to-column moment connections used in moment-resisting frames （MRFs） were tested to study the failure process, failure mode, strength and plastic rotation capacity. The specimens include one traditional welded flange-bolted web connection, one traditional fully welded connection, four beam flange strengthened connections, three beam flange weakened connections, and one through-diaphragm connection. The test results show that the connections with flange cover plates or with partly cut beam flanges satisfy the beam plastic rotation demand for ductile MRFs. From the measured stress profiles along the beam flange and beam web depth, the mechanics of brittle fracture at the end of the beam is discussed. Design recommendations for steel beam-to-column moment connections are proposed.     

Seismic performance of a 3D full‐scale high‐ductile steel–concrete composite moment‐resisting frame—Part II: Test results and analytical validation

This paper presents the results of a multi‐level pseudo‐dynamic seismic test program that was performed to assess the performance of a full‐scale three‐bay, two‐storey steel–concrete composite moment‐resisting frame built with partially encased composite columns and partial‐strength beam‐to‐column joints. The system was designed to develop a ductile response in the joint components of beam‐to‐column joints including flexural yielding of beam end plates and shear yielding of the column web panel zone. The ground motion producing the damageability limit state interstorey drift caused minor damage while the ultimate limit state ground motion level entailed column web panel yielding, connection yielding and plastic hinging at the column base connections. The earthquake level chosen to approach the collapse limit state induced more damage and was accompanied by further column web panel yielding, connection yielding and inelastic phenomena at column base connections without local buckling. During the final quasi‐static cyclic test with stepwise increasing displacement–amplitudes up to an interstorey drift angle of 4.6%, the behaviour was ductile although cracking of beam‐to‐end‐plate welds was observed. Correlations with numerical simulations taking into account the inelastic cyclic response of beam‐to‐column and column base joints are also presented in the paper together. Inelastic static pushover and time history analysis procedures are used to estimate the structural behaviour and overstrength factors of the structural system under study. Copyright © 2008 John Wiley & Sons, Ltd.     

Numerical models and ductile ultimate deformation response of post‐tensioned self‐centering moment connections

New steel moment‐resisting connections that incorporate post‐tensioning elements to provide a self‐centering capacity and devices to dissipate seismic input energy have recently been proposed and experimentally validated. Experimental studies have confirmed that these connections are capable of undergoing large lateral deformations with negligible residual drifts. To facilitate their implementation, accurate modeling of the behavior of systems incorporating post‐tensioned connections must be readily available to designers and researchers. A number of simplified models have been suggested in the literature by researchers trying to capture experimental results at the beam–column connections and thereby to predict the global response of structures incorporating such connections. To provide a clear set of guidelines for the modeling of post‐tensioned steel frames, for practicing engineers as well as researchers, in this paper three types of numerical models of increasing complexity are presented: (i) a sectional analysis procedure, (ii) a lumped plasticity spring frame leveled approach and (iii) a non‐linear solid finite element analysis to predict the response at ultimate deformation levels. The analytical results obtained from the numerical models predict well the structural behavior of these connections when compared with available experimental data. Even at the ultimate deformation level, analytical results are in good agreement with test results. Furthermore, detailing requirements are proposed to assure that flexural hinges form in the beams in order to improve the cyclic response of steel self‐centering connections when drifts exceeding the design drifts are imposed to the system. Experimental and analytical studies demonstrate that steel post‐tensioned self‐centering connections incorporating the proposed detailing in the beams develop an increased deformation capacity and thereby exhibit a ductile response while avoiding a sudden loss of their strength and stiffness. Copyright © 2008 John Wiley & Sons, Ltd.     

Simplified seismic fatigue evaluation for rigid steel connections

A simplified fatigue-life model is proposed for assessing the seismic inelastic rotational capacity of steel connections. First relations are developed for rigid steel connections under lateral loading. Next this is extended to account for the effects of the welded steel moment frame (WSMF) connections of the so-called pre-Northridge type. The seismic fatigue theory is validated against experimental results. The experiments were conducted under increasing ductility amplitudcs until the onset of fracture. Miner‘ rule was used to convert the test results to given an equivalent constant amplitude cyclic fatigue life. Satisfactory agreement is obtained when comparing the experimental observations with the theoretical predictions.     

低周反复荷载作用下矩形钢管混凝土柱与钢梁连接节点的受力性能

本文进行了2种矩形钢管混凝土柱与钢梁连接节点——翼缘全螺栓(BFP)连接节点与外加强环(WFP-BW)连接节点在柱端低周反复荷载作用下的抗震性能试验,分析比较了这2类节点与焊接翼缘板(WFP)连接节点在不同轴压比下的滞回性能、强度与刚度退化、延性比与耗能比、破坏机理与破坏特征,得出了一些有参考价值的结论。