【作者】 黄超；

【导师】 韩小雷；

【作者基本信息】 华南理工大学 ， 结构工程， 2010， 博士

【摘要】 斜交网格结构体系是一种新型的结构体系,其主要特征为竖向构件采用斜向相交的柱代替普通竖直柱,以形成多个三角形几何不变体抵抗外部荷载。斜交网格体系具有抗侧刚度大,抗风抗震性能好的优点,近年来已应用于超高层及高层建筑结构中。研究表明,斜交网格柱受力以轴压为主,采用圆钢管混凝土作为其斜柱构件,能很好地发挥其轴压承载力高、延性好的优势。但由于斜交网格结构的节点处有包括4根斜柱在内的至少6根结构构件相汇,节点的构造设计与力学性能成为斜交网格结构能否广泛应用于工程实践的关键问题。本文在总结有关钢管混凝土和斜交网格结构体系的大量文献资料的基础上,对钢管混凝土斜交网格结构体系的力学性能进行了研究和分析,并针对该结构提出了一种由4根圆钢管、椭圆形连接板、环向加强板、环板、加劲肋板和节点外伸牛腿组成的相贯节点。该节点具有传力明确、承载力高、质量轻、性能好、施工方便,能有效地连接上下部斜交网格柱等特点,实现钢管混凝土斜柱节点空间相贯,有很好的工程应用前景。本文采用试验研究、三维非线性有限元分析和力学理论方法对此类相贯节点的受压力学性能进行了研究,具体包括以下几方面的内容:1)以节点构造措施、平面内角度、加载方式为研究参数,对8个平面相贯节点试件的试验过程、破坏形态、受力性能等进行了详尽的分析,验证了该种新型钢管混凝土斜交网格相贯节点的构造措施合理,节点的承载能力满足设计要求。分析了各参数对试件承载力、应变发展过程及延性等力学性能的影响,结果表明,环向加强板+衬板型节点力学性能优于法兰板节点,宜采用全节点区内衬板加强,以提高整个节点区对核心混凝土的约束效应。2)提出一种刚度协调的多向加载试验方法,以节点平面内、平面外角度、椭圆形连接板厚度、加载方式为研究参数,进行了8个空间相贯节点试件的试验研究,详尽地分析了各参数对节点力学性能和试验后试件内部形态的影响,结果表明相贯节点具有较好的力学性能,可用于工程实践。3)对现有混凝土三维非线性本构模型进行评述,提出一种适用于相贯节点的核心混凝土等效应力-应变关系,并对该模型进行了校核。采用该模型对平面相贯节点和空间相贯节点进行了三维双重非线性有限元分析,揭示了节点的传力机理,椭圆形连接板、环向加强板和衬板均有效地增大了节点区的约束效应,提高节点承载力。采用相同模型,分别研究了平面内相贯角度、平面外相贯角度、椭圆形连接板厚度、环向加强板厚度、衬板厚度、平面外约束等参数对节点承载力和刚度的影响。4)对平面相贯节点的弹性刚度和极限轴压承载力进行了力学分析,指出节点的破坏截面,通过12个带钢板的钢管混凝土短柱轴压试验研究了其承载力。基于修正的核心混凝土模型,采用有限元分析方法对核心混凝土强度、钢管壁厚和钢板厚度对节点破坏截面承载力的影响进行深入研究,提出并验证了节点破坏截面、平面相贯节点和空间相贯节点的承载力计算公式。5)基于筒体结构的受力特征,提出一种矩形平面斜交网格结构的斜柱截面估算方法,最后将本文提出的相贯节点成功应用于广州一幢超高层建筑的工程实例,介绍了其实际应用效果。该节点力学性能优良、施工简便、经济性好,在工程应用中取得了显著的经济效益和社会效益,证明其具有较广泛的适用性和应用前景。更多还原

【Abstract】 Diagrid structural system is an innovative structural system, which commonly utilizes intersecting diagonal members instead of the conventional vertical columns as structural supporting system. Compared to conventional frame structures, diagrid structures can provide much larger lateral stiffness and better performance to resist most of the horizontal loads such as wind loads and earthquake effect owing to the triangulated configuration. These advantanges make diagrid structural system widely used in high-rise buildings recently. Previous research indicates that diagonal members carry much larger axial compressive forces than conventional columns, thus circular concrete filled steel tubular (CFST) columns, which can offer high compressive strength and high ductility, are apparently ideal for use in diagrid structural systems. However, connection design is one of the most great challenges of diagrid structural systems because more than six components from various angles are concentrated at one point. In other words, the design and mechanical behavior of the connection are indeed essential for spreading application of diagrid structural system.Based on the conclusion of an amount of references on CFST structures and diagrid structural system, the behavior of CFST diagrid structures was studied, and a kind of intersecting connection with four circular steel tubes, an elliptical plate, a ring reinforcing plate, two ring plates, several stiffening ribs and brackets was proposed. This connection provides high strength, light weight, outstanding structural performance and convienence in construction. In addition, it can effectively connects upper and lower diagonal columns and makes the columns intersecting each other, has a blooming prospect in field construction. By means of experimental study, three dimensional nonlinear finite element analysis (FEA) and mechanical theoretical method, this paper studies the compressive behavior of the intersecting connection, including the following aspects:1) Based on the test results of eight planar intersecting connection specimens with different connection details, in-plane angles and loading types, comprehensive analyses on the test procedure, failure modes and structural behavior are conducted. The details are proved to be reasonably designed and the bearing capacity can fulfilled the requirement stipulated by Chinese codes. The effect of parameters on the behavior of specimens such as bearing capacity, development of the strain and the ductility are analyzed. Test results indicate that the connection with ring reinforcing plate and lining plate provides better performance than the connection with flange plate. Therefore, the confinement effect on the concrete core should be reinforced by increasing the thickness of the steel tubes in the connection zone. 2) A stiffness-based multiple direction loading test method was proposed and applied to a series test of eight spatial intersecting connection specimens with different in-plane and out-of-plane angle, thickness of elliptical plate and loading type. The effect of parameters on the behavior and internal failure modes is analyzed, and the behavior of the intersecting connection is verified to be excellent for practical use.3) An equivalent constitute model for concrete core of intersecting connection is proposed based on evaluation on currenet three-dimensional nonlinear constitute models for concrete. A three-dimensional dual nonlinear FEA is conducted on planar and spatial intersecting connections to investigate the stress distribution. The confinement effect and the bearing capacity of the connection zone are remarkably increased by introduction of elliptical plate, ring reinforcing plate and lining plate. In addition, the effect of in-plane and out-of-plane angles, thickness of elliptical plate, ring reinforcing plate, lining plate and out-of-plane constraint on the behavior of connection are analyzed using the similar model.4) The elastic stiffness and ultimate bearing capacity of the planar intersecting connection is analyzed by mechanical method, the failure cross-section for the connection is assumed. A series test of 12 CFST stub column with a gusset plate under axial compressive loading was conducted on the purpose of investigating the bearing capacity. The effect of different concrete strength, thickness of steel tube and gusset plate on the bearing capacity of the failure cross-section is analyzed by FEA and modified model. As a result, the formulate for calculating the bearing capacity of failure cross-section, planar intersecting connection and spatial intersecting connection is put forward and veried by test and FEA results.5) Based on the structural behavior of tubular structures, a method to estimate the section area of diagonal columns in diagrid structures with rectangular plan is deduced. As a result, the connection proposed in this paper has been applied to an ultra high-rise building in Guanghzou, the details and applied advantages are introduced. Excellent mechanical behavior, convienence in construction and satisfactory commercial results make the intersecting connection ideal for use in the diagrid structures.更多还原