【作者】 刘迪；

【导师】 李帼昌；

【作者基本信息】 沈阳建筑大学 ， 结构工程， 2016， 硕士

【摘要】 钢管混凝土是实际工程中应用最为广泛的钢与混凝土组合结构,其具有承载力高、塑性韧性好、经济效益好、耐火以及方便施工等特点。现如今,世界各地的学者已对钢管混凝土构件进行了深入而全面的研究。然而,目前关于研究高强钢材与高强混凝土同时替代普通材料的钢管混凝土结构的相关报道仍然较少。本文通过试验与有限元模拟相结合的方法对高强方钢管高强混凝土纯弯构件的力学性能进行了全面研究。试验设计了两组共6个钢管壁厚分别为4mm,5mm,6mm的试件,采用三分点的加载方式进行研究,观察试件的破坏形态,研究纯弯构件的工作机理。利用ABAQUS有限元分析软件模拟与试验同规格的试件,通过对模型本构关系、边界条件、网格划分等的调整使得有限元模拟构件的破坏形态以及荷载-挠度曲线与试验构件的吻合程度良好。在试验与有限元模拟的基础上,更深入的研究了纯弯构件受力全过程中的弯矩-曲率关系曲线、混凝土应力应变分布、钢管应力应变分布、各组份分别承担荷载的大小以及中性轴的变化规律。分析了不同含钢率、钢管屈服强度、混凝土抗压强度对纯弯构件极限承载力、抗弯刚度、延性等的影响。分析了我国GB50936(2014)、欧洲EC4(1994)、日本AIJ(1997)以及美国AISC-LRFD(1999)规范中抗弯承载力计算公式的适用性。同时,通过大量有限元分析,采用数据拟合的方法推导出了高强方钢管高强混凝土构件的抗弯承载力的计算公式。研究表明,组合构件中高强钢管和高强混凝土在弯矩作用下能很好的协同工作,构件的弯矩-曲率曲线大致可以分为弹性阶段、弹塑性阶段以及强化三个阶段;构件的极限承载力随着含钢率、钢管屈服强度以及混凝上的抗压强度的提高而提高,抗弯刚度和延性系数的大小也随着含钢率的增大而提高;利用EC4(1994)规范的承载力公式计算得到的结果与试验和模拟结果均吻合较好,且承载力实测值与计算值的比值的离散性最小,经综合分析,EC4(1994)规范适用于高强方钢管高强混凝土的抗弯承载力计算;利用试验数据验证了抗弯承载力推导公式的正确性。更多还原

【Abstract】 Concrete filled steel tube(CFST)has the characteristic of high bearing capacity,good plasticity,good toughness,good economic performance,fire resistant and convenient construction.The CFST is one of the steel-concrete composite structure which has been widely used in practical engineering.The scholars all over the world have carried out a comprehensive study on the CFST,however,the report of the research about high-strength concrete filled high-strength square steel tube(HCFHST)which used high-strength materials instead the ordinary steel and concrete are still less.In this paper,a comprehensive analysis was presented on the mechanical behavior of HCFHST subjected to pure bending by the test and finite element analysis methods.The test prepared a total of 6 specimens which divided into two groups that each one of them were the steel tube wall thickness of 4mm,5mm and 6mm.The test used third point loading method,then observed the failure mode and study the mechanism of the bending members.The ABAQUS was used to do the finite element analysis,than adjusted the constitutive modes,boundary conditions and meshes to make the simulation results fit well with the test results on failure mode and load-displacement curves.Based on the deep research of the test and simulation,the moment-curvature relationship,the distribution of steel stress and strain,the distribution of concrete stress and strain,bearing capacity of each component and the changing rule of the neutral axis were studied.Moreover,analyzed the influence of the bearing capacity,stiffness and ductility index by different steel ratio,yield strength of steel tube and compressive strength of concrete.Examined the calculation formula of flexural bearing capacity by different codes which included GB50936(2014),EC4(1994),AIJ(1997)and AISC-LRFD(1999).Then derived a formula to calculate the bearing capacity for the HCFHST.The study showed that the high-strength concrete worked well with the high-strength steel under bending moment.The bending moment-curvature relationship can be divided into elastic stage,elastic-plastic stage and strengthening stage.The bearing capacity of the HCFHST increased with the increase of steel ratio,steel yield stress and concrete compressive stress.The flexural stiffness and ductility also increased with the increase of steel ratio.The EC4(1994)code offered a suitable formulation for calculating the bearing capacity of the HC.FHST by a comprehensive analysis.The test data of’ flexural bearing capacity verify the validity of the derived formula.更多还原