装配式钢管混凝土柱-双钢梁框架节点受力性能试验研究

针对一种适合装配式结构的钢管混凝土柱-双钢梁框架体系,对其2个典型平面节点和2个典型空间节点进行单调和循环加载试验,以研究加载模式和节点类型对节点破坏形态、承载力、刚度、延性及耗能能力的影响。结果表明：试件的破坏均发生在梁端,柱与节点域保持完好,满足“强柱弱梁、强节点弱构件”的抗震设计要求;试件的位移延性系数为2.6~3.6,能量耗散系数为1.7~2.2,耗能能力与型钢混凝土节点相当;加载模式(单调或循环)相同而节点类型(平面或空间)不同时,节点性能差异小;加载模式不同而节点类型相同时,节点性能差异大：循环荷载作用下的节点梁端焊缝发生拉裂破坏,位移延性系数较小。该种节点静力性能较好,但从提高抗断裂能力出发,需进一步改进构造,对焊缝分布进行优化设计。     

Effect of gusset connection configurations on frame–gusset interaction in steel buckling‐restrained braced frame

Although buckling restrained braces (BRBs) are commonly applied in seismic buildings to mitigate structural damage, their performance was often limited by rupture of the corner gusset connections due to additional frame action. This issue may be resolved by alternative gusset connections to mitigate the frame–gusset interaction. In this study, commonly used procedures for design of the traditional gusset connection are reviewed, followed by a case study on the effect of frame action on the structural behavior of these gusset connections in steel frames with BRBs. Inspired by these analysis, two different strategies, aiming at releasing frame–gusset shear interaction using sliding gusset connection or reducing normal interaction using dual gusset plates, are tried to mitigate the frame action effects. Finite element analysis is conducted on steel frame subassemblages with/without BRBs to examine the effect of different gusset connections on the structural behavior of these framing systems. It shows that the sliding gusset connection shows beneficial effect in reducing the frame action, having much smaller stress responses on the gusset interfaces, as well as smaller shear force and plastic responses on the framing system. Thus, it becomes a promising gusset connection for improved seismic performance of the steel framing system with brace‐type dampers.     

Beam‐column connections of concrete‐filled double steel tubular frame structures

Four types of concrete‐filled double steel tubular (CFDST) columns were introduced in this paper, which had the advantage of higher bearing capacity, stronger stiffness, and better fire‐resistant and explosion‐resistant performance. To research a reasonable form of beam‐column connection is the top priority in CFDST frame structures. After a brief historical background concerning the development of CFDST columns, this study conducted an investigation and comparison of several existing beam‐column connections. The constructional detail and force transfer mechanism of each beam‐column connection were analyzed according to the present research achievements. Several finite element models were established to discuss the various connection configurations and main factors affecting their behaviors. In general, connection design can take full advantage of the characteristic of double tubes in CFDST structure, so a series of construction improvements for joint design parameters in CFDST frame structures was proposed to improve the seismic performance and the relevant study for the future work was also discussed.     

Effect of different size of joint enlargement on seismic behavior of gravity load designed RC beam‐column connections

Effect of different size of planer joint enlargement as a noninvasive and practical strategy for seismic retrofit of gravity load designed external reinforced concrete beam‐column connections was experimentally investigated. The joint region was enlarged using steel angles that are mounted using prestressed cross‐ties. Reverse cyclic load tests on five half‐scale control and retrofitted external RC beam‐column connections were conducted. Three different size of planer joint enlargement being 180, 140, and 90 mm were considered for retrofitted specimens. The performance of the retrofitted specimens is compared with that of the control gravity load designed beam‐column connections, in terms of load–displacement hysteresis curve, energy dissipation and ductility capacities, and global strength and stiffness degradation behavior. The experimental results showed that increasing the size of planer joint enlargement significantly enhances the seismic capacity of the retrofitted connections, in terms of strength, stiffness, energy dissipation, and ductility capacity and also planer joint enlargement can relocate beam plastic hinges to outside the joint panel.     

联方型弦支穹顶研究

在分析天保中心弦支穹顶的工程实例及相关研究的基础上,提出了弦支穹顶的二阶段分析方法。采用二阶段分析方法,对选定的结构模型,与单层网壳相比较,分析了联方型弦支穹顶的结构性能。研究了不同矢跨比、不同撑杆长度、不同节点刚度等参数变化条件下联方型弦支穹顶的特性,同时考虑了不同的荷载组合情况。对联方型弦支穹顶进行了屈曲分析。研究分析结果表明弦支穹顶须按预应力模型进行分析;联方型弦支穹顶是一种高效的结构形式,其屈曲承载力大于相应的单层球面网壳;二阶段分析法是弦支穹顶一种有效的分析设计方法;较为浅平的弦支穹顶的拉索预应力应进行专项分析;撑杆较长有利于增大抵抗力并避免环向拉索的松弛;不对称荷载为主要工况时有必要对拉索的松弛进行专题校核分析。     

我国平板网架结构的发展现状

本文总结论述了我国迅速发展的平板网架结构,并详细对结构的形式、连接方法、计算分析、施工与质裣、以及屋面材料、支座形式和防火、防锈涂料等方面发展状况进行了评述,最后还列示了有代表性的几十个典型工程实例。     

多栓接头中螺栓不同时承压问题的研究

在多栓连接中，由于制做加工上的原因，螺栓孔距出现偏差，从而导致接头中的螺栓在连接受力的过程中不同时进人承压状态．本文利用概率统计理论，对此问题进行了分析研究，得出了多栓接头中螺栓不同时承压系数及螺栓进人承压状态所需变形量等重要结论，供从事钢结构研究、设计及规范修订工作者参考。     

城与水的有机联系——滨水空间与城市

滨水空间是滨水城市中重要而具有代表性的部分,但今天,它与城市的联系却出现了问题。文章试图探讨通过设计方法,加强滨水空间与城市的联系,使滨水空间更有活力和吸引力。文章借用了景观生态学等方法,同时结合实例进行了探讨。     

钢结构建筑组合节点的分析模型

针对钢 -混凝土组合节点的工作特性 ,简要介绍了组合节点的 4种分析模型 ,可供采用组合节点的结构分析与设计参考     

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.