中空夹层钢管混凝土—钢管K形连接节点工作机理研究

发布时间：2018-03-04 14:32

本文选题：中空夹层钢管混凝土　切入点：组合K形节点　出处：《清华大学》2014年博士论文　论文类型：学位论文

【摘要】：中空夹层钢管混凝土是一种新型组合构件，已在电力杆塔等工程结构中得到应用。当其充当桁架或塔架结构中的弦杆时，常与空钢管腹杆组成K形节点，而以往对该类组合节点设计原理的研究尚少见报道。本文研究圆截面中空夹层钢管混凝土-钢管K形连接节点（以下简称为“中空夹层钢管混凝土K形节点”）的工作机理和设计方法，主要研究工作和研究结果如下： 1.研究了中空夹层钢管混凝土构件在侧向荷载作用下的力学性能。以杆件空心率、径厚比、管径比和侧向荷载角度为参数，开展了系列试验。研究结果表明，侧向荷载作用下的中空夹层钢管混凝土试件表现出良好的延性性能，其承载能力和变形能力明显优于相应的空钢管构件。建立了有限元分析模型，研究了构件的受力全过程和典型破坏模态，深入认识了侧向荷载作用下钢管与混凝土间的传力机制。 2.进行了中空夹层钢管混凝土K形节点在轴向荷载作用下的系列试验研究。实现了两种典型边界的加载，研究了中空夹层钢管混凝土弦杆空心率、腹弦杆管径比、弦杆轴力水平等参数下节点的力学性能变化规律。结果表明，组合节点承载能力强，在弦杆空心率为0~0.6、腹弦杆管径比为0.4~0.6时，发生弦杆进入塑性、受压腹杆屈曲的破坏形态。 3.建立了中空夹层钢管混凝土K形节点受力全过程分析的有限元模型。模型中考虑了材料与几何非线性、钢管和混凝土间的相互作用，计算结果得到试验结果的验证。利用有限元模型，，研究了组合节点的典型破坏形态和全过程荷载-变形关系，实现了对特征点处弦杆、腹杆材料应力发展的细致分析，深入认识了节点的受力全过程工作机理。 4.研究了中空夹层钢管混凝土K形节点承载力实用计算方法。对影响组合节点性能的参数，如中空夹层钢管混凝土弦杆空心率、腹弦杆管径比、弦杆径厚比、弦杆轴力水平等进行了细致的计算分析，在此基础上针对夹层混凝土的局部承压破坏、弦杆表面塑性失效等典型破坏形态，提出了相应的承载力实用计算方法，计算结果与试验结果及有限元分析结果均吻合良好。
[Abstract]:Concrete filled hollow sandwich steel tube (CFST) is a new type of composite member, which has been used in engineering structures such as power towers. When it acts as a chord in truss or tower structure, it often forms K-shaped joints with hollow steel tube webs. However, previous studies on the design principle of this kind of composite joints are rarely reported. In this paper, the circular section hollow sandwich steel tube concrete-filled steel tube K-shaped connections (hereinafter referred to as "hollow sandwich concrete filled steel tube K-joints") are studied in this paper. Working mechanism and design method, The main research work and findings are as follows:. 1. The mechanical properties of hollow sandwich concrete-filled steel tube members under lateral load are studied. Taking the hollow ratio, diameter to thickness ratio, pipe diameter ratio and lateral load angle as parameters, a series of tests are carried out. The concrete filled hollow sandwich steel tube specimens under lateral load show good ductility, their bearing capacity and deformation capacity are obviously superior to those of the corresponding hollow steel tube members. The finite element analysis model is established. The whole process and typical failure modes of members are studied, and the mechanism of force transfer between steel tube and concrete under lateral load is deeply understood. 2. A series of tests of hollow sandwich concrete-filled steel tube (CFST) K joints under axial load are carried out. The loading of two typical boundaries is realized, and the hollow ratio of hollow sandwich concrete filled steel tube chords and the diameter ratio of web chords are studied. The results show that the combined joint has a strong bearing capacity. When the chord hollow ratio is 0 ~ 0.6 and the diameter ratio of a web chord is 0.4 ~ 0.6, the chord enters into plasticity and the buckling of the web member under compression occurs. 3. A finite element model for the analysis of the whole process of stress of hollow sandwich steel tube concrete filled steel tubular joints is established. The material and geometric nonlinearity and the interaction between steel tube and concrete are taken into account in the model. The finite element model is used to study the typical failure form and load-deformation relationship of the composite joints, and the stress development of chords and webs at characteristic points is analyzed in detail. The working mechanism of the whole process of the joint force is deeply understood. 4. The practical calculation method of bearing capacity of hollow sandwich concrete-filled steel tube K joints is studied. The parameters affecting the performance of composite joints, such as hollow ratio of hollow sandwich concrete filled steel tube chords, diameter ratio of web chords, ratio of diameter to thickness of strings, are studied. Based on the detailed calculation and analysis of the axial force level of the chord, a practical calculation method for the bearing capacity of sandwich concrete is put forward in view of the typical failure modes such as local bearing failure and plastic failure of the chord surface. The calculated results are in good agreement with the experimental results and the finite element analysis results.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU398.9

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