外伸端板高强螺栓连接三维非线性有限元分析

对外伸端板高强螺栓连接采用三维非线性有限元分析方法,对连接中的主要构件端板、高强螺栓、梁翼缘、柱翼缘和柱翼缘加劲肋进行精细模拟,针对有无柱加劲肋、端板厚度变化等连接的情况进行比较分析,研究了外伸端板高强螺栓半刚性连接的受力性能以及其初始刚度的影响因素。     

钢管混凝土L形柱-H型钢梁Z字形拼接节点受力性能分析

对一种钢管混凝土L形柱-H型钢梁Z字形拼接节点进行了有限元参数分析。通过改变7种参数,建立22个模型,分析各节点的受力性能。分析表明:工程中可以省去腹板处拼接板的连接、采用削弱型上下部翼缘加劲肋替代矩形上、下部翼缘加劲肋;增加翼缘高强螺栓数量,能够提高节点的承载能力和总耗能,但是延性性能有所降低;增加翼缘高强螺栓预拉力,能够提高节点的滑移荷载和总耗能,延缓节点的滑移;增加上、下部翼缘加劲肋厚度,能够提高节点的正向峰值荷载和总耗能;增加上、下部翼缘加劲肋高度,能够提高节点的滑移荷载和总耗能;上部翼缘加劲肋能够显著提高节点的受力性能。各节点具有良好的延性和塑性转动能力。     

L形钢管混凝土柱-H型钢梁Z字形拼接节点抗震性能研究

研究了一种L形钢管混凝土柱-H型钢梁Z字形拼接节点的抗震性能,包括翼缘和腹板均拼接的节点和设置上、下部翼缘加劲肋替代腹板处拼接板的节点.通过对节点的拟静力试验和研究,获得了节点的滞回曲线、滑移荷载、屈服荷载、极限荷载、耗能能力、延性与刚度退化规律,分析腹板处拼接板和翼缘加劲肋对节点抗震性能的影响.研究结果表明:腹板处拼接板可以提高节点的屈服荷载和极限荷载.增加翼缘高强螺栓数量可以提高节点的滑移荷载,但会降低节点的延性性能.垂直加劲肋可以提高节点的屈服荷载、极限荷载和延性.对比有无上、下翼缘加劲肋的两组节点可知,上、下翼缘加劲肋可以提高节点的承载能力,有效传递拼接区的剪力,可代替腹板连接,该节点具有良好的延性和塑性转动能力.     

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。     

螺栓角钢钢节点的三维非线性有限元分析

对螺栓角钢钢节点半刚性连接采用非线性有限元分析方法 ,对连接中的主要构件的顶部、底部、腹板角钢、高强螺栓、梁翼缘、柱翼缘和柱翼缘加劲肋进行三维非线性有限元精细模拟 ,针对有无柱加劲肋、有无腹板角钢等几种连接的情况进行比较分析 ,探讨了螺栓角钢半刚性连接的受力性能。     

地震下可恢复框架结构冷弯型钢构件试验研究

对地震时作为多层建筑抗弯钢架能量耗散构件的薄壁冷弯型钢(CFS)进行了试验研究。试验采用6个螺栓连接的梁-柱节点,在连接区域的板件和梁的翼缘上使用不同的出平面加劲肋。CFS连接件的滞后性能表明其具有较高的耗能能力和足够的延性,满足抗震设计规范的要求。在连接区域的钢梁内使用出平面加劲肋,能够提高连接件的弯矩-转角特性,强度提高35%,延性提高75%。弹性周期后连接件的滑动使其具有较好的滞回性能,能量耗散能力提高了240%。连接件试样可以作为刚性连接,其全部或部分强度取决于连接加劲肋。     

梁柱端板连接节点柱翼缘、柱腹板加强方法有限元分析北大核心

根据"强柱弱梁"的需求,梁柱端板连接节点处柱部分的加强方式一般有设置横向加劲肋、节点域内腹板加补强板、柱翼缘外加补强板、角钢内贴柱翼缘螺栓连接、角钢外贴柱翼缘螺栓连接等方式。采用有限元软件ABAQUS建立三维有限元模型,对这些不同形式、不同构造的钢框架梁柱端板连接进行了非线性有限元分析(FEA)。通过分析比较可知:同时设置横向加劲肋与腹板补强板能够较好地限制柱子的变形,大幅度提高节点的初始刚度与强度;而角钢内贴柱翼缘栓焊连接、角钢外贴柱翼缘螺栓连接不仅能够满足建筑管线通道的需求,同时也能够提升节点初始刚度与强度,也便于弱轴采用螺栓连接。     

半刚性端板连接节点性能的非线性有限元分析

采用三维接触单元来模拟端板与柱翼缘的接触面,预应力单元来模拟螺栓的预拉力,对半刚性端板连接节点性能进行了非线性有限元分析。计算结果的比较分析表明,节点域加劲肋、端板加劲肋、端板厚度、螺栓预拉力、应力集中等因素对半刚性端板连接节点域的受力性能均有较大影响。建议在设计中采取相应构造措施,考虑端板节点半刚性的不利影响。     

高强螺栓外伸端板的刚性连接设计

钢框架节点设计中,梁与柱强轴方向的刚性连接通常采用端板式连接。分析了影响梁柱节点连接刚性的三个因素,包括端板厚度、柱加劲肋的设置和柱翼缘补强板设置与否。探讨了外伸端板厚度的计算公式和柱加劲肋的计算方法。根据受力分析,推导了柱翼缘补强板厚度的公式,为工程设计提供了一些参考。     

含可更换剪切型耗能梁段钢框筒子结构抗震性能的数值分析

含可更换剪切型耗能梁段钢框筒利用位于裙梁跨中的耗能梁段集中塑性变形,有利于震后耗能梁段的替换和结构使用功能的快速恢复。为研究耗能梁段的构造对子结构和耗能梁段滞回性能的影响,基于某一30层原型结构的子结构,考察了耗能梁段长度、腹板高厚比、翼缘宽厚比、加劲肋间距、加劲肋单双面布置的影响。研究表明:随着耗能梁段长度的增加,子结构的承载力逐渐减小,耗能梁段的超强系数、塑性转角逐渐减小,建议耗能梁段的长度取柱距的(0.15~0.24)倍;随着腹板高厚比的增大,各子结构的承载力、累积耗能明显减小,耗能梁段的超强系数、塑性转角逐渐增大,极短型耗能梁段相比普通型耗能梁段对腹板高厚比的变化更为敏感;翼缘宽厚比的变化对子结构和耗能梁段性能的影响较小;当加劲肋间距超过限值,对极短型耗能梁段性能的影响较大,建议普通型耗能梁段的加劲肋间距可适当超过限值;极短型耗能梁段宜布置双面加劲肋,加劲肋单面布置时增加其厚度对子结构和耗能梁段性能的改善作用较小。     

The effect of stiffeners on the strain patterns of the welded connection zone

The behavior of the welded I-beams to box-columns connections is investigated both experimentally and numerically to identify the effects of stiffeners and column flange thickness on the energy dissipation characteristic of the connection. Numerical test specimens were developed and analyzed by the finite element method and the results were compared with full-scale experiments. The effects of various stiffeners such as, column stiffeners, side-stiffeners, and top-flange, and bottom-flange stiffeners were investigated. The contribution of each stiffener in controlling the location of the plastic deformation and the energy dissipation in the connection zone were examined.     

Experimental behaviour of concrete filled thin walled steel tubes with tab stiffeners

This paper presents an experimental investigation into the structural behaviour of concrete filled, thin walled, steel tubular stub column with tab stiffeners. The stiffening was attained by welding together four pieces of lipped angle, whereupon two parts of the lips were notched and folded vertically in order to form the tab stiffeners. The effects of the tab stiffeners on the bond and compressive strengths were investigated experimentally using 18 and 10 specimens respectively. It was observed that the tab stiffener does enhance both the bond strength and the axial load capacity of the concrete filled thin walled steel tubular stub column tested.     

设纵肋钢箱混凝土轴压短柱试验研究

为研究钢箱内填混凝土、含钢率以及钢箱内纵向加劲肋是否开孔等对钢箱混凝土轴压短柱力学性能的影响,进行了3个钢箱混凝土和1个钢箱轴压短柱的模型试验。试验结果表明：钢箱内填混凝土可有效提高试件的轴压刚度和承载力;纵肋可充分参与构件整体受力,其中纵肋开孔试件变形能力更强,延性更好。与设纵肋薄壁钢管混凝土短柱现有试验数据对比表明：随含钢率的提高,混凝土强度提高系数有所增大。建议设纵肋钢箱混凝土轴压短柱承载力可按叠加原理进行计算,其中钢箱截面积可计入纵肋的面积。     

The effect of stiffener on behavior of reduced beam section connections in steel moment-resisting frames

Reduced Beam Section (RBS) connections are a new type of connection which have been used in steel moment-resisting frames since the 1994 Northridge earthquake. This study is primarily aimed at analyzing the effects of suitable web stiffeners on preventing the deterioration effect of the hysteresis curve for RBS connections. Results of more than 183 nonlinear finite element analyses on different IPE sections with radius cut, straight cut, and drilled-flange RBS connection showed that different web stiffeners considerably contribute to the enhancement of seismic performance of RBS connections. In this research, the effects of factors such as the geometry and the number of the stiffeners, the distance between the stiffener and column side, and the length and thickness of the stiffener on the seismic performance of RBS connections were also studied.     

反复荷载作用下L形钢管混凝土柱滞回性能研究

本文介绍了7根L形钢管混凝土柱试件在承受常轴力和水平荷载作用下的试验研究.试验中考虑了不同的轴压比、内部有无加劲和加载方式对试件抗震性能的影响.试验结果表明.内部加劲能够明显地延缓柱子钢板的屈服,而且柱子的耗能能力和延性也有较好的改善.最后通过编写计算程序,对L形钢管混凝土柱的荷载-变形进行了全过程分析.考察了常用的方钢管混凝土柱的钢材和混凝土的本构关系对L形钢管混凝土柱纤维模型数值分析的适用性,计算得到的弯矩一轴力一曲率关系和荷载一位移关系与试验结果吻合较好.     

钢筋加劲T形截面钢管混凝土柱抗震性能试验研究

制作4根钢筋加劲的T形截面钢管混凝土柱、1根非加劲T形截面钢管混凝土柱和1根T形截面钢筋混凝土柱试件,对其进行低周往复水平荷载作用下的滞回性能试验,研究其破坏模式和滞回性能,分析钢筋加劲肋的作用机理以及钢管对混凝土的约束作用。结果表明：相比T形截面钢筋混凝土柱,T形截面钢管混凝土柱破坏程度有明显减轻,刚度、承载力以及耗能性能均有明显提高;钢筋加劲肋能有效限制钢板局部屈曲和阴角处钢管与混凝土脱离,保证钢管和混凝土共同工作,对拉钢筋加劲肋相对锯齿形钢筋加劲肋的效果更加显著;含钢率较高的钢管混凝土柱承载力更高,耗能能力更好;轴压比从0.2增加到0.4时,钢筋加劲的T形截面钢管混凝土柱的承载力增大,延性降低。     

开孔钢板加劲的矩形钢管钢纤维高强混凝土柱轴压试验研究

为探明加劲肋类型、开孔钢板（PBL）开孔间距、钢纤维体积掺量、混凝土强度等级等对矩形钢管钢纤维高强混凝土（SFRHC）柱轴压破坏模式的影响规律,对10根柱进行了轴压性能试验,得到了其荷载-压缩变形曲线、位移延性系数、耗能指标和破坏模式。研究结果表明：与PBL加劲试件相比,钢板加劲试件和未加劲试件的位移延性系数分别降低11.9%和10.4%,耗能指标分别降低8.3%和5.6%, PBL加劲肋能有效加强钢管与核心混凝土的组合作用。掺入体积率为0.8%钢纤维的PBL加劲试件,其位移延性系数和耗能指标分别提高12.5%和42.3%,钢纤维体积率为0.8%~1.2%时,试件位移延性系数和耗能指标明显提高。加劲SFRHC柱为肋间管壁局部外鼓破坏,PBL加劲柱的破坏位置均位于PBL开孔处,未加劲SFRHC柱为管壁外鼓破坏,对应钢板屈曲处核心混凝土表现为压碎破坏,钢纤维被整体拔出;加劲SFRHC柱沿高度方向破坏位置明显下移,钢板加劲肋和PBL加劲肋均能有效分担轴向荷载。     

Experimental behaviour of stiffened concrete-filled thin-walled hollow steel structural (HSS) stub columns

Test results on concrete-filled steel tubular stub columns with inner or outer welded longitudinal stiffeners under axial compression are presented in this paper. The research was mainly focused on square hollow section (SHS) columns; two rectangular hollow section (RHS) columns were also tested. A longitudinal stiffener was provided on each side of the stiffened SHS column, while only two stiffeners were welded to the longer sides of the stiffened RHS column. The main experimental parameters considered were the height-to-thickness ratio and stiffener rigidity. In addition, empty tubes with or without stiffeners, as well as unstiffened concrete-filled steel tubes were also tested for comparison. Requirements for stiffener rigidity are developed by modifying a formula presented in the literature. Existing theoretical model and design codes were used to predict the load versus axial strain relationships and load-carrying capacities of the adequately stiffened composite sections respectively; reasonable results were achieved.     

Application of steel channels as stiffeners in bolted moment connections

This paper proposes a stiffening method to meet some architectural needs. This method uses bolted channels as alternatives to both continuity and doubler plates in bolted moment-resistant beam-to-column connections. The present study investigates the performance of channels as stiffeners to: increase yield load in the tension zone of connection, gradually increase overall moment capacity of connection, and avert shear failure of the column web panel zone. We conducted experiments to examine the tension region of the connection loaded from T-stubs. The moment capacity of full connection was predicted by considering T-stub idealization and shear effects on the column web panel. T-stub tensile behavior and overall connection behavior were also monitored using three-dimensional finite element simulations in ANSYS simulation software because this problem is three-dimensional in nature. Effects of geometrical and material non-linearities on interaction among connecting members should be clarified. This study showed marked strength improvement in connection by use of channels. The performance of channel stiffeners was examined through comparison of results.     

Stiffness requirements for transverse stiffeners of rectangular CFT compression panels

This paper presents a more rational calculation of the minimum stiffness required for transverse stiffeners of stiffened concrete filled tube (CFT) compression panels. As longitudinal stiffeners are essentially compression members, transverse stiffeners are required to control the effective length. Both the longitudinal stiffener and transverse stiffener subdivide the compression panel in a grid pattern so the relatively thin plate can carry the induced compressive load in the most efficient manner. However, the provisions for the required rigidity of transverse stiffeners in the literature are inconsistent in general and in particular; do not exist in the case of the concrete filled compression panels. Here, the parameters that govern the behavior of the transverse stiffeners are identified theoretically using the column buckling approximation. In order to calibrate and quantify the analytical equations developed, incremental nonlinear analyses were performed on a large number of finite-element models. The numerically collected data were then used to validate the equations developed.