【作者】 刘威；

【导师】 韩林海；

【作者基本信息】 福州大学 ， 结构工程， 2005， 博士

【摘要】 合理地对钢管混凝土局压受力进行设计是目前有关工程界关心的热点问题之一,在以往设计规程中尚未得到很好的解决,有关研究,尤其是理论研究工作还不够深入。关于方钢管混凝土局压方面的研究工作则尚未见报道。本文从理论和实验两方面较深入地研究了钢管混凝土局部受压时的力学性能和工作机理,并在系统参数分析结果的基础上提供了钢管混凝土局压承载力实用计算方法。本文具体进行了以下几个方面的工作: (1)以局压面积比、截面含钢率和端板刚度为主要参数,进行了26个圆形和56个方形试件局部受压时的力学性能实验研究,较为系统地考察了局压面积、钢管约束、截面形状、端板及尺寸的影响规律,对比了钢管混凝土和素混凝土、钢管混凝土带端板与否等的力学性能差异。本文还通过钢管混凝土的推出实验,考察了钢管和混凝土界面粘结力的变化规律。(2)在大量算例分析的基础上,本文提出钢管混凝土的核心混凝土本构关系模型,并成功地利用通用有限元分析软件ABAQUS对钢管混凝土局部受压时的荷载-变形全过程进行了计算。计算结果表明,与以往研究者进行的同类工作相比,本文提供的核心混凝土本构关系模型具有力学概念明确、通用性强的特点。通过对收集到的529个钢管混凝土和126个钢管约束混凝土全截面受压实验结果,以及本文和其他研究者进行的97个钢管混凝土局压实验结果的验算,充分说明本文采用的理论计算方法是可靠的。(3)采用本文给出的理论计算方法,对钢管混凝土局部受压情况下的荷载-变形全过程关系曲线进行了分析。考察了局压面积比、截面含钢率和端板刚度等因素的影响规律,首次从理论方面较深入地揭示了钢管混凝土受局压时的工作机理。(4)系统分析和考察了局压面积比、截面含钢率、钢材和混凝土强度以及端板相对刚度半径等参数对钢管混凝土局压承载力的影响规律,在此基础上提出了局压承载力计算方法,分析结果表明,该方法概念清晰,符合实用原则,可为有关工程实践和规程制订提供参考。更多还原

【Abstract】 How to reasonably design concrete-filled steel tubes(CFST) under local compression is one of the hot topics in the relevant engineering field now. It was not solved in the past design code yet. The related research needs to do further, especially theory research. The research on CFST with square section under local compression is not reported to date. Behaviours and mechanism of CFST under local compression were investigated in this paper, including theoretical and experimental studies. Based on the systemic analysis of parameters, practical computational methods for local compression bearing capacity of CFST were given. In this paper, the main achievements were summarized in detail as follows: (1) The local compression area ratio, steel ratio and rigidity of end plates were chosen the main parameters. Experimental studies on the behaviours of CFST under local compression were carried out, including 26 circular CFST specimens and 56 square CFST specimens. Influence of local compression area, steel confinement, section shape, end plate and its size were studied. The differences between CFST and plain concrete, and between CFST with and without end plate were compared. Furthermore, push-out tests were conducted to investigate the bond stress in the interface between concrete and steel tube. (2) Based on a large amount of computational examples, the constitutive model of core concrete of CFST was suggested. Load-deformation curve of CFST under local compression was obtained by ABAQUS, which is a common analysis software by finite element method(FEM). From the results, it can be seen that the constitutive model of core concrete in this paper has the advantages of clear mechanics concept and easy using. By verifying lots of test results using the computational method in this paper, such as axially loaded 529 CFST members and 126 steel tube confined concrete members selected from other researchers, and 97 CFST members under local compression in this paper and from other researchers, it can be proved that this method is reliable. (3) Load-deformation curves of CFST under local compression were analysized through the computational method given by this paper. The influence of local compression area ratio, steel ratio and rigidity of end plates was investigated. It is the original work that the local compression mechanism of CFST was discovered deeply . (4) Influences of local compression area ratio, steel ratio, strength of steel and concrete, and relative rigidity radius of end plates on local compression bearing-capacity of CFST were investigated systemically. On this basis, the method to calculate the local compression bearing capacity was suggested. The results indicate that the method has clear mechanics concept, and easy using, which can supply practical engineering and specifications with reliable references.更多还原