加劲外伸端板连接的弯矩-转角性能分析

提出新的理论模型,用于评估加劲外伸钢梁-柱端板连接的弯矩-转角(M)关系。根据对端板连接转动的定义,将端板连接分解为多个组成部分,包括面板区、螺钉、端板和柱翼缘。并对各个组成部分完整的加载-变形过程进行了分析。最后通过整合各个部分的反应得出整个连接件的加载-变形过程。此外,通过5个节点试验验证这个分析模型。对计算与试验结果比较可以得出,该分析模型可以准确评估端板连接的转动能力、弯矩-转角曲线和初始转动刚度。而且,它还可以分析对节点转动变形起作用的其他因素,如面板区的剪切变形、螺钉的拉长、端板和柱翼缘的弯曲变形等。该分析模型同时提供弯矩-剪切转角(Ms)和弯矩-缝隙转角(Mcp)曲线,这些曲线为详细分析端板连接的转动性能提供了可靠的基础。     

Development of moment-rotation model equations for flush end-plate connections

This paper presents the development of Ramberg-Osgood and Three-Parameter Power model prediction equations for the moment-rotation (M-θ) behavior of flush end-plate connections with one row of bolts below tension and compression flanges. A finite element model (FEM) of the connection region along with the connected beam and column is developed for load deformation analyses, which included material, geometric, and contact nonlinearities. The FEM model was verified with test results conducted and reported for flush end-plate connections in the literature during the 1980s. A matrix of test cases was obtained by varying the geometric variables of flush end-plate connections within their practical ranges. The connection M-θ data for these test cases were obtained by FEM analyses, which were then curve fitted to Ramberg-Osgood and Three-Parameter Power model equations to obtain parameters defining these equations. Finally, prediction equations were developed for parameters of the model equations as functions of geometric variables of the flush end-plate connections.     

方钢管钢骨混凝土柱与钢梁端板螺栓连接节点抗震性能试验研究

为研究方钢管钢骨混凝土柱与钢梁端板螺栓连接节点的抗震性能,进行了5个节点拟静力试验研究,分析了端板厚度、螺栓直径、混凝土强度和轴压比等因素对承载力、弯矩-转角曲线、耗能能力、承载力衰退、刚度退化、延性以及破坏模式的影响。研究结果表明：方钢管钢骨混凝土柱与钢梁端板螺栓连接节点均属于半刚性节点,初始转动刚度随着端板厚度和螺栓直径增大而提高,但节点的极限转动能力随着端板厚度的增大而减小;当承载力由端板或钢梁控制时,其具有良好的转动和耗能能力;试件承载力退化系数在0.8～1.0之间,变化幅度不大,刚度退化相比荷载退化严重;设计中应避免高强螺栓发生脆性破坏。     

Influence of initial imperfection on the behaviour of extended bolted end-plate connections for portal frames

Initial imperfection in bolted end-plate connections is mainly induced by residual deformation of welding. Three typical initial imperfections, namely V-shape, C-shape and W-shape are identified in terms of the geometrical imperfection shapes for extended bolted end-plate connections based on a field study. Seven specimens of extended bolted end-plate connection, among which six specimens with V-shape initial imperfection and one without imperfection in the end-plates were tested, and the influence of the initial imperfection of the end-plate on the behaviour of the connections was investigated. Test results show that initial rotation stiffness of extended bolted end-plate joints decreases with increase of initial imperfection in the end-plate, however, the strength of the end-plate joints is only affected slightly by the imperfection. Besides, the thicker the end-plate is, the more reduction in the initial rotation stiffness relatively. Further parametric study on 14 extended bolted end-plate connections with three typical shapes of imperfections were conducted based on the finite element analysis. Among the three types of initial imperfection, the V-shape has the least influence, and the C-shape has the biggest influence on the initial rotation stiffness of the extended bolted end-plate joints. For initial geometrical imperfection in a V-shape, its influence on behaviour of extended bolted end-plate connections is negligible as far as the imperfection is limited to the criterion, giving H/300. The influence of initial imperfection in a W-shape on rotation stiffness should be acceptable if the initial imperfection is limited to the criterion. In the case of a C-shape initial imperfection in the end-plate, its influence on the rotation stiffness would be substantial; even it satisfies the requirement of the imperfection limit. The results of the study should be applicable to the bolted end-plate connections, whether flushed or extended end-plate beam to column joints in structural frames.     

地震作用下端板连接的特性

试验测试了循环荷载作用下的一组8个足尺的钢梁柱端板连接弯矩。研究的参数有端板厚度、螺钉直径、外伸端板加劲肋、柱加劲肋、齐平/外伸端板的类型。试验结果反映在弯矩能力曲线、转角刚度、转动能力和滞回曲线上。试验结果显示:延伸的端板连接有足够的强度、节点转动刚度、延性和抗震结构中要求的耗能能力。基于试验结果和分析,提出了在钢结构抗震设计中对端板连接弯矩的一些详细要求,为保证在地震作用下端板连接能够提供足够的转动能力和耗能能力,并使最终破坏模式为延性破坏,推荐了三种失效模式和相应的抵抗能力。为考虑端板连接向两侧延伸,本文还提出了一种双线性的运动硬化弯矩-转角(M-R)滞回模型。     

超大承载力端板连接节点试验研究

在大跨或重载钢结构中,当梁柱之间需要采用螺栓连接时,如果普通构造的端板连接节点和大承载力端板连接节点不能满足承载力要求,则需要采用受拉区布置12颗或16颗螺栓的超大承载力端板连接节点。为研究该类型节点受力性能,进行4个超大承载力端板连接节点足尺试件的单调加载试验,得到各节点试件的弯矩-转角曲线,分析不同螺栓直径、端板厚度和螺栓布置形式下各节点的抗弯承载力、转动刚度和受拉区螺栓拉应变增量分布的特点。结果表明,在试验试件构造条件下超大承载力端板连接节点的弯曲失效模式为端板屈服后螺栓失效,端板厚度对节点承载力影响明显;各螺栓的拉应变增量分布不均匀,角部螺栓对节点抗弯承载力影响较小,建议在设计中移除或仅按抗剪螺栓考虑;建议节点域屈服承载力仍按照现行规范计算,该类节点的等效受拉螺栓数量取为7。     

多层钢框架半刚性端板连接的循环荷载试验研究

为研究多层钢框架半刚性梁柱端板连接的抗震性能,对8个不同构造端板连接足尺试件进行了循环荷载试验研究, 分析了端板厚度、螺栓直径、端板外伸加劲肋、柱腹板加劲肋、平齐式和外伸式等因素对节点承载力、转动刚度、极限转动 能力、耗能能力、延性和极限破坏状态的影响。试验结果表明,半刚性梁柱端板连接具有良好的延性和耗能能力,可以应用 于多层抗震钢框架中。根据试验结果及相关分析,提出了多层抗震钢框架中端板连接的标准构造为:两端外伸,设置柱腹 板加劲肋和三角形端板加劲肋,柱翼缘在端板外伸边缘上下各100mm范围内局部加厚,厚度与端板厚度相同。对提高端 板连接节点的抗震性能提出了宜采用大直径螺栓、中等厚度端板的设计建议。本文还在"强节点,弱构件"抗震设计一般原 则的基础上提出了"强连接,弱板件"的端板连接抗震设计概念。     

FE model of beam-to-column extended end-plate joints

The rotational behaviour of steel end-plate connections can be studied using the finite element method for the following three reasons: 1) such models are inexpensive and robust; 2) they allow the understanding of local effects which are difficult to measure accurately physically; and 3) they can be used to generate extensive parametric studies. This paper presents a full three-dimensional ANSYS finite element model of steel beam to column bolted extended end-plate joints for use to obtain their behaviour. The model includes: contact and sliding between different elements; bolt pre-tension; and geometric and material non-linearity.The model was calibrated and validated with experimental results found in the literature and with the model proposed by Eurocode 3. The results from the finite element analysis were verified by comparing the obtained moment-rotation curve of the joint. The procedure for determining the moment-rotation curve using finite element analysis is also given, together with a brief explanation of how the design moment resistance and the initial rotational stiffness of the joint are obtained.     

信息动态

建立可靠的力学模型,使其能模拟循环荷载作用下足尺T型节点的全过程弯矩-转角曲线。由于螺栓之间相互作用且对连接的转动刚度有影响,螺栓连接的性能很复杂。将节点模型设计为由各个T型组件组成,并用线性弹簧模拟各组件。通过从荷载-位移反应机制得出的多线性刚度模型,分析组件的性能,包括受拉螺栓隆起、T型翼缘的弯曲、T型腹板的拉伸、相对滑移变形、允许变形等。将这些属性代入节点单元中的弹簧,能较准确地分析足尺节点性能。基于基本弹簧理论,集中阐述刚度模型,更好地分析了螺栓连接的性能、失效模型及T型组件韧性。     

不同排列伸展螺栓端板半刚性节点的三维非线性分析

对钢结构中不同排列的伸展螺栓端板这种半刚性连接节点采用非线性有限元分析 ,对连接中的主要构件 :端板、高强螺栓、梁翼缘、柱翼缘以及连接接触进行三维非线性有限元精细模拟 ,针对不同的尺寸和截面进行比较分析 ,探讨了螺栓端板半刚性连接的受力性能     

Mechanical modeling of bolted T-stub connections under cyclic loads Part I: Stiffness Modeling

This paper deals with mechanical models which make it possible to reliably simulate the complete moment-rotation curves in the full-scale T-stub connections subjected to cyclic loads. The behavior of these bolted connections becomes complex because the various response mechanisms of individual connection components interact with one another and have influence on the overall rotational stiffness of the connection. Accordingly, the mechanical joint models are made up of individual T-stub components modeled as nonlinear springs. The behaviors of component members including tension bolt uplift, bending of the T-stub flange, elongation of the T-stem, relative slip deformation, and bearing deformation are reproduced by the multi-nonlinear stiffness models obtained from their force-deformation response mechanisms. These stiffness properties should be assigned into the component springs implemented into the joint element so as to numerically generate the behavior of full-scale connections with considerable accuracy. Thus, this part (Part I) intends to focus on describing the stiffness models, which are based on the basic component spring theory, in an effort to provide insight into the behavior, failure modes, and ductility of T-stub components in the connection.     

端板连接高强度螺栓群中和轴位置研究

为研究端板连接中高强度螺栓群的中和轴位置变化,对门式刚架外伸式端板连接进行了试验研究与理论计算.试验采用4种梁截面尺寸,选择端板厚度和端板加劲肋作为研究参数,对12个试件进行了单调加载试验,通过在螺栓杆无螺纹区开槽粘贴应变片测量了端板螺栓力的变化情况.理论计算系建立带弹性支座的连续梁模型模拟端板连接,将模型计算结果与试验结果比较分析,结果表明：加载过程中,螺栓群中和轴逐渐从其形心轴向受压区移动,但不超过受压翼缘内侧螺栓中心线;极限状态下,受拉翼缘和端板可简化为等效T型件.根据理论模型,进行了简单的参数分析,研究了撬力、端板厚度和螺栓排列等对连接性能的影响.最后结合试验结果及理论计算,对现有计算方法进行了评价.     

Experimental investigation of beam-to-column connection with SHN490 steel under cyclic loading

Seismic performance of beam-to-column connections used in the middle-low rise buildings was investigated through the cyclic loading test. Four joint specimens were prepared in accordance with the variables of material and connection type. In two cases of welded connection, the brittle fracture in weld did not occur but cracked at heat-affected zone (HAZ) and/or near weld access hole. In the connections with extended end-plate, punching failure followed by end-plate failure occurred at the flange of column around bolt head. The moment capacities based on failure modes were calculated and compared with the test results. The connections were classified as rigid, semi-rigid, flexible in terms of bending stiffness and strength.

     

梁柱端板连接节点的初始转动刚度计算模型

首先利用分解法建立了梁柱螺栓端板连接节点的力学模型 ,然后基于梁板理论给出了节点初始转动刚度的解析公式。公式综合考虑了端板变形、柱翼缘以及螺栓对初始转动刚度的贡献 ,可方便地推广于平端板和外伸加劲端板连接初始转动刚度的计算。公式计算结果和试验结果以及有限元分析结果作了对比 ,吻合较好。同时给出了便于工程设计的简化公式。     

钢框架梁柱连接节点转动刚度试验研究

为了探讨钢框架梁柱连接节点的转动刚度和破坏模式,针对常见梁柱节点类型,包括全焊接连接、外伸式端板螺栓连接、T型钢螺栓连接、上下翼缘及腹板角钢螺栓连接等,进行了单向加载试验研究。试验结果表明,各类节点的总转角均超过了0.05 rad,塑性转角均超过了0.04 rad;节点域剪切变形较大,特别是全焊接节点,使节点转动刚度显著降低;当连接较强时,框架梁可以在连接破坏之前形成塑性铰;当连接较弱时,连接件容易因过度变形而破坏。通过对试验数据的分类整理分析,梁柱节点总转角可以分成节点域转角和连接转角两大部分,给出了常见节点类型在弹性阶段的转角及转动刚度简化计算方法,并与试验结果进行了对比,计算结果与试验结果吻合较好。     

Steel beam-column connection using copper-based shape memory alloy dampers

This study presents the details of an experimental investigation on a prototype partially restrained connection using copper-based shape memory alloy (SMA) bars. The proposed configuration consists of an end-plate connection between a rectangular hollow structural steel beam and a wide flange steel column, where four CuAlBe () bars, in austenitic phase, are used to prestress the end-plate to the column flange. A physical model of the connection was tested by applying a controlled cyclic displacement history at the tip of the beam with two different characteristic frequencies of 0.25 and 1 Hz. Potentiometers and load cells were used to measure strains and stresses in the bars and the displacement and load applied at the beam tip. Similar bars, with the same thermal treatment, had been previously tested in cyclic tension at several nominal strains and frequencies, showing superelastic behavior for deformations up to 2.3% strain. In static tensile tests, the fracture strain was approximately 8%, with a transgranular fracture mechanism. The equivalent damping ratio for the single bar test increases for larger strains, being 6% for a 2.3% strain. The beam-column connection also exhibited superelastic behavior, a moderate level of energy dissipation, and no strength degradation after being subjected to several cycles up to 3% drift. Finally, a set of numerical simulations are conducted to compare the performance of a rigid steel frame and a partially restrained frame with SMA connections using a three-story benchmark structure.     

外伸端板高强螺栓受拉连接的计算分析

针对国内外关于外伸端板高强螺栓受拉连接的受力分析方法,研究端板刚性、弹塑性、塑性和T形件4种力学计算模型。端板刚性分析中将端板按无弯曲变形的刚性体考虑;弹塑性分析中假定受拉翼缘两侧的两排螺栓承担相同拉力,并考虑端板的部分塑性变形;塑性分析中每个螺栓的受力依赖于其本身的承载力,各排螺栓随拉力的增大依次达到屈服;T形件模型考虑端板的弹塑性变形,将受拉翼缘和螺栓简化为T形连接件。通过例题研究4种计算模型下高强螺栓受拉连接的计算方法,可为工程设计提供参考。     

Finite element analysis on the static behaviour of wide-type large capacity end-plate connections

Compared to the traditional two-column-bolt layout, the wide-type end-plate connections with four bolts in a row could resist a greater moment. In this paper, a detailed verified finite element model is employed to analyse the static behaviour of six wide-type end-plate connections, where parameters such as the end-plate thickness, bolt layout, extended or flushed end plate and the geometry of the stiffener are covered. The simulation results demonstrate that (1) in the elastic range, the transferred tension force of the bolts far from the beam web is about 0.33～0.67 times that of the closer ones; (2) the shear force in the bolts is tiny; (3) at the ultimate state the bolts located far from the beam flange have a significant contribution to the loading capacity of the connection while it shows little contribution in the elastic state. In addition, a yield-line model of the tension part of the end plate is proposed.     

高强螺栓端板连接的撬力分析与研究

利用有限元软件ANSYS分析和研究了外伸端板高强螺栓受拉连接接头破坏的Mises等效应力云图、端板变形、撬力分布以及螺栓拉力变化及分布。证明了撬力在端板连接中是显著存在的;增加端板厚度及设置加劲肋能够减小撬力影响;撬力的作用使高强螺栓拉力提高,外伸端板高强螺栓拉力的分布是以受压翼缘为转动中心的梯形分布。提出了考虑撬力作用的理论计算公式,算例结果表明,考虑撬力设计的计算公式较为简单并具有较好的设计适用性。