钢框架栓焊梁柱连接节点的抗震设计

节点设计是整个钢结构设计的重要环节,提高钢框架梁柱连接节点的抗震性能是整个钢结构抗震设计的重要内容.本文主要介绍了提高钢框架栓焊梁柱连接节点的抗震设计的主要措施,主要方法包括:通过加腋和加盖板对节点进行加强,提高节点承载力;对梁局部削弱,使塑性铰从节点区外移至梁上;改进节点区焊接孔构造形式,缓解局部应力集中;妥善处理弧板和垫板,减少焊缝缺陷.     

梁柱节点处粘钢加固作法研究

介绍了一种新的异型钢板粘钢加固负弯矩区抗弯不足的作法,并对其与规范中作法进行了有限元分析对比,结果表明这种作法可以有效提高被加固梁的承载力,使挠度明显降低,并且有效地抑制了裂缝在构件中的开展,计算证明此方法有效且可靠.     

纤维增强复合材料加固混凝土柱研究综述

从纤维增强材料(FRP)约束混凝土柱的本构关系,FRP加固轴心受压和偏心受压构件的影响因素,力学性能、抗震性能等几个方面总结了该加固方法的国内外研究现状,分析了在FRP加同混凝土柱的研究中存在的问题,明确了需进一步开展研究工作的方向.     

Seismic behavior of code designed steel plate shear walls

The AISC Seismic Design Provisions now include capacity design requirements for steel plate shear walls, which consist of thin web plates that infill frames of steel beams, denoted horizontal boundary elements (HBEs), and columns, denoted vertical boundary elements (VBEs). The thin unstiffened web plates are expected to buckle in shear at low load levels and develop tension field action, providing ductility and energy dissipation through tension yielding of the web plate. HBEs are designed for stiffness and strength requirements and are expected to anchor the tension field formation in the web plates. VBEs are designed for yielding of web plates and plastic hinge formation at the ends of the HBEs.This paper assesses the behavior of code designed SPSWs. A series of walls are designed and their behavior is evaluated using nonlinear response history analysis for ground motions representing different hazard levels. It is found that designs meeting current code requirements satisfy maximum interstory drift requirements considering design level earthquakes and have maximum interstory drifts of less than 5% for maximum considered earthquakes. Web plate ductility demands are found to be significantly larger for low rise walls than for high rise walls where higher modes of vibrations impact the response. The percentage of story shear resisted by the web plate relative to the boundary frame is found to be between 60% and 80% and is relatively independent of panel aspect ratio, wall height, or hazard level, but is affected by transitions in plate thickness. Maximum demands in VBEs in design level shaking are found to be considerably less than those found from capacity design for SPSWs with 9 or more stories.     

Seismic retrofit of square reinforced concrete piers by ferrocement jacketing

An experimental investigation was conducted to strengthen shear deficient reinforced concrete columns using ferrocement jacketing. Three scale model specimens, identical to the actual bridge piers, were tested. One of the piers was tested under as-built condition while the other two were strengthened with layers of wire mesh before being tested. All the specimens were subjected to a simulated seismic loading and constant axial load. It was observed from the experimental results that the ferrocement-jacketed specimens exhibited enhanced stiffness, strength, energy dissipation and ductility and the mode of failure changed from brittle shear failure to a ductile flexural failure. The control specimens failed by shear at a relatively low lateral displacement. A finite element model was developed and the results obtained from the numerical analysis compared well with the experimental results. A design methodology for strengthening piers with square/rectangular columns with inadequate shear strength using ferrocement jackets is also presented.     

Statistical evaluation of steel beam-column resistance

Statistical data on uniaxial and biaxial bending of beam-columns is compared with existing interaction equations in several standard specifications. The mean values and coefficients of variation for the professional factors of these equations are evaluated. An alternative set of ultimate strength parameters for use in the equations are proposed, to reduce the scatter in the availble data. The validity of the proposed interaction equation is confirmed.     

FRP单面加固带裂纹钢板的应力强度因子分析

对单面粘贴FRP的带裂纹钢板进行了线弹性断裂力学分析,研究了裂纹尖端的应力强度因子变化,分析结果表明,经过FRP加固后,钢板的应力强度因子显著降低;随着FRP刚度的增加,应力强度因子逐渐减小。     

现行建筑抗震设计规范多高层钢结构梁柱刚性连接设计方法的技术矛盾

对我国现行《建筑抗震设计规范》中关于多高层钢结构房屋梁柱刚性节点连接的设计规定进行了深层次分析,指出该规定与同一规范第5.4.2条的强连接要求存在矛盾。在相同设计条件下按照规范的规定做多遇地震作用下的连接设计时,可分别设计出三种抗震性能相差悬殊的连接作法。按照规范公式Mu≥1.2Mp进行中震或大震作用下弹塑性阶段的抗震连接计算时,得出的结果却不能满足抗震要求,存在安全隐患。为了确保满足规范第5.4.2条应实现强连接的抗震设计强制性条文规定,提出了相应解决方案,针对所讨论的问题进一步推出几种耐震型连接节点作法和相应的计算方法,推荐了既有良好抗震性能又较符合我国国情的新型节点形式。     

Seismic retrofit of structures using steel honeycomb dampers

The purpose of this paper is to investigate the seismic performance of a honeycomb shaped steel hysteretic damper applied to seismic retrofit or strengthening of a structure. The formulas for the initial stiffness and yield strength of a damper unit were derived based on the cell wall bending model, and the results were compared with those obtained from finite element analysis. Bilinear model of the honeycomb damper was developed based on the nonlinear force-displacement relationship obtained from finite element analysis. The honeycomb dampers were applied for seismic retrofit of a 15-story apartment building designed without considering seismic load and for seismic design of a 3-story moment frame designed with reduced seismic load. The analysis results showed that the honeycomb dampers were effective in the enhancement of seismic-load resisting capacity of the model structures.     

关于型钢混凝土梁柱节点的思考

介绍了型钢混凝土梁柱节点的连接类型及节点设计的注意事项,对型钢混凝土结构节点构造形式与梁柱节点的抗震性能进行了分析,并总结了型钢混凝土节点施工技术难点,对类似工程施工具有借鉴作用。     

钢框架梁柱节点断裂研究

简述了钢框架梁柱节点断裂的研究背景,结合国内外相关研究现状,探讨了梁柱节点连接形式及设计思想,分析了造成断裂的原因,研究了结构分析中的损伤概念及疲劳理论,从而从整体上把握节点断裂规律。     

Bracing systems for seismic retrofitting of steel frames

The present study assesses the seismic performance of steel moment resisting frames (MRFs) retrofitted with different bracing systems. Three structural configurations were utilized: special concentrically braces (SCBFs), buckling-restrained braces (BRBFs) and mega-braces (MBFs). A 9-storey steel perimeter MRF was designed with lateral stiffness insufficient to satisfy code drift limitations in zones with high seismic hazard. The frame was then retrofitted with SCBFs, BRBFs and MBFs. Inelastic time-history analyses were carried out to assess the structural performance under earthquake ground motions. Local (member rotations) and global (interstorey and roof drifts) deformations were employed to compare the inelastic response of the retrofitted frames. It is shown that MBFs are the most cost-effective bracing systems. Maximum storey drifts of MBFs are 70% lower than MRFs and about 50% lower than SCBFs. The lateral drift reductions are, however, function of the characteristics of earthquake ground motions, especially frequency content. Configurations with buckling-restrained mega-braces possess seismic performance marginally superior to MBFs despite their greater weight. The amount of steel for structural elements and their connections in configurations with mega-braces is 20% lower than in SCBFs. This reduces the cost of construction and renders MBFs attractive for seismic retrofitting applications.     

Fire response of steel semi-rigid beam-column moment connections

This study investigates the fire response of steel semi-rigid beam-column moment connections made with H-shape beam and H-shape column. The general purpose finite element software ANSYS was adopted. The numerical model was verified by the full-scale fire tests implemented in the building fire laboratory center of the Architecture and Building Research Institute (ABRI) in Taiwan, and its results were found to agree well with experimental results. The numerical results show that the applied moments have significant effects on the stiffness of steel moment connections in addition to material properties and connection geometry.     

Seismic performance of buckling-restrained braced frames with varying beam-column connections

The effect of beam-column connections and brace configurations on the overall seismic response of a medium-rise bucklingrestrained braced frame (BRBF) is analytically evaluated in the present study. Two types of brace configurations (chevron and Double-X) and a combination of the moment-resisting and the non-moment-resisting beam-column connections are considered. A total of five design cases are studied for a seven-story BRBF in which a constant value of response reduction (R) factor equal to 8 is considered in the design. Nonlinear dynamic analyses are carried out for all study frames for an ensemble of forty ground motions representing the DBE and MCE hazard levels. Fragility curves are developed for all study frames considering the interstory drift ratio and residual drift ratio as the damage parameters. Results showed that a higher value of response reduction factor should be adopted in the design of BRBFs for both pinned and rigid beam-column connections. Further, in order to achieve the desired seismic performance of BRBFs, Double-X brace configurations and rigid beam-column connections at the alternate story levels should be used.     

FRP约束钢筋混凝土柱的抗震性能研究现状

纤维增强聚合物(FRP)以其轻质、高强、抗腐蚀、耐疲劳及其温度稳定性而受到土木工程界的日益关注，近年来被广泛地用于各种形式结构的修复和加固。从结构试验、计算理论和计算方法三个方面，阐述了国内外研究者对FRP约束钢筋混凝土柱抗震性能的研究现状，分析了研究中存在的不足，并对FRP约束钢筋混凝土柱的抗震性能今后的研究提出了展望。     

Seismic performance improvement of circular steel columns using precompressed concrete-filled steel tube

This paper presents a new method aimed at improving seismic resisting characteristics of circular-shaped steel columns representing highway bridge piers and an experimental investigation carried out to validate it. In this method, a special compression member is placed in the middle of the pier in order to take the axial load from the superstructure. As a result, the influence of axial load on the inelastic buckling deformation of plates can be greatly controlled. The special compression member consists of a precompressed concrete-filled steel tube (PC-CFT). Six specimens were tested to check the seismic performances of the proposed column system. It was clear from the test results that the specimens with PC-CFT could deform even up to ten times of their yield displacements without significant load deterioration. They also showed improved ultimate strength, ductility and energy absorption capacities than the corresponding benchmark specimens.     

Experimental study of beam-column behaviour of steel single angles

Twenty-eight rolled steel single angle specimens were tested to investigate their response when required to carry axial compressive loading at various end eccentricities. Results suggested that when eccentrically loaded with respect to the major principal axis, there is a critical eccentricity below which any consequent reduction in the ultimate load is marginal. In contrast, as eccentricity of loading with respect to the minor principal axis is increased, reduction of the ultimate load is more pronounced and no similar critical eccentricity can be identified. Test results, when compared with the corresponding values as determined from the design equations suggested by Adluri and Madugula (1992), in AISC Specification 2000 and AISC Specification 2005, indicated that the former two methods give a conservative estimate of the ultimate compressive capacity of single angles. This conservatism is more pronounced for specimens subjected to eccentric loading with respect to the major principal axis than that resulting from eccentric loading with respect to the minor principal axis. Although intended for doubly symmetric sections, the third method provides improved capacity estimates of single angles.     

冷弯型钢梁柱抗弯节点受力性能的影响

采用有限元分析方法,以螺栓直径和螺栓间距、C型钢屈服强度、厚度和截面高度、节点板厚度等为参数,建立梁柱抗弯节点的三维非线性有限元模型,对影响节点受力性能的因素进行了分析,并在此基础上对这种连接节点提出了设计建议。     

劲性钢骨混凝土梁柱节点施工技术

结合工程实例,介绍了劲性钢骨混凝土梁柱节点的施工原理,从前期策划、二维数据参数核定、钢骨柱安装等方面,阐述了劲性钢骨混凝土梁柱节点的操作要点,解决了梁柱节点处型钢与钢筋之间的排布连接问题。