【作者】 杨正宇；

【导师】 王玉银；

【作者基本信息】 哈尔滨工业大学 ， 防灾减灾与防护工程， 2008， 硕士

【摘要】 方形钢管混凝土具有截面抗弯刚度大、节点构造简单、易于装修等特点,工程应用日益增多。但方钢管对核心混凝土的约束作用不均匀,承载力和延性较同等截面尺寸的圆钢管低,且管壁易发生局部屈曲。为了改善方钢管混凝土的受力性能,本文提出了一种设置钢筋加劲肋的方钢管混凝土新型构件,并开展了以下几方面工作:(1)进行了8个设置加劲肋的方钢管混凝土和2个普通的方钢管混凝土轴压短柱试验,观察并分析了试件的变形特点、破坏模式和破坏机理。研究结果表明:钢筋加劲肋可以防止钢板过早发生局部屈曲,增强钢管对核心混凝土的约束作用,改善了试件的延性和承载力。但由于钢管宽厚比较大,端部效应影响显著,试件易发生端部破坏。(2)基于本文和他人的试验研究结果,利用有限元软件ABAQUS建立并验证了方钢管混凝土轴压短柱的有限元模型,对比分析了不同加劲肋形式对方钢管混凝土构件的承载力、延性及变形能力的影响。结果表明,圆形箍筋和斜置的矩形钢筋加劲肋对试件承载力和延性的改善最为显著;钢筋加劲肋中与钢管壁垂直的钢筋段是提高构件延性及变形能力的主要因素。(3)基于试验研究及理论分析,提出了两种构造简单、施工方便、造价低廉并能有效改善钢管对混凝土约束效果的斜拉及对拉钢筋加劲肋形式,并分析了钢管屈服强度、含钢率、钢筋直径和屈服强度等参数对钢筋加强的方钢管混凝土构件力学性能的影响。更多还原

【Abstract】 As the strong bending-rigidity of the cross-section, simple connection details and decoration convenience, the Square Concrete-filled Steel Tubular columns (square CFST) have been increasingly applied in engineering practice. Nevertheless, the strength and ductility of square CFST are inferior to those of the circular CFST, due to its low confinement to core concrete and the premature local buckling of the steel plates. In order to improve the mechanical performance of square CFST, an innovative type of columns with steel bar stiffeners was put forward in this paper. The main contents are listed as follows:(1) 8 square CFST stub columns with stiffeners and 2 without stiffeners were tested under axial compression load. The features of deformation, failure models and failure mechanism were observed and analyzed. The test results show that the columns can be strengthened by adding the steel bar stiffeners. The steel bar stiffener can prevent the specimens from premature local buckling, which would enhance the confinement to concrete and improving the ultimate compression strength and ductility. However, the relatively large width-to-thickness ratio of the steel plates has obvious effects at the ends of the columns, which can cause the end failure.(2) Based on the experimental results of this paper and other reference, a finite element model were established and verified with ABAQUS software for square CFST under axial compression. The influences of stiffener shapes on the bearing capacity, ductility and deformation capacity of square CFST were analyzed and compared. Analysis results showed that circular stirrups and aslant-arranged rectangle steel bar stiffeners were superior to other shapes considering the improvement of the bearing capacity and the ductility. The steel bar stiffeners perpendicular to the plate are the main contributor to increase the ductility and the deformation capacity.(3) Based on the experimental and theoretical research,two new types of bar stiffener details was suggested, which is structurally simple, convenient in construction, low cost and a better results in improving the confinement of steel bar to core concrete. Beside, the finite element parametric analysis was carried out for the stub CFST columns with or without steel bar stiffeners. A detailed discussion was carried out for the influence of steel plate strength, steel plate thickness, steel bar diameter and strength.更多还原