【作者】 李斌；

【导师】 赵鸿铁；

【作者基本信息】 西安建筑科技大学 ， 结构工程， 2005， 博士

【摘要】 钢管混凝土结构是在钢管中填充素混凝土而形成的一种组合结构,是在劲性钢筋混凝土结构、螺旋配筋混凝土结构以及钢结构的基础上演变和发展起来的一种新型结构形式。该结构中,钢管与混凝土协同工作,优势互补,克服了二者单独受力时的缺陷,使其极限承载能力得到大幅提高,延性和塑性性能得到较大的改善,较之其他结构形式具有明显的优势,适应了建筑工程的现代化发展趋势,在实际工程中得到了广泛的应用。 本文针对钢管混凝土结构的受力特点,以及目前对该种结构的研究现状和实际使用中存在的问题,通过试验与理论相结合的方法,研究了钢管混凝土构件的约束效应、短柱承载力计算及影响因素、中长柱的稳定承载力计算及影响因素,以及钢管混凝土框架结构的受力性能和抗震性能;所得的研究成果可供工程设计人员参考并指导工程实践。 在钢管混凝土约束效应系数的研究中,从分析核心混凝土强度提高系数出发,建立了约束效应系数ξ(ξ=(f_yA_s/(f_ckA_c)))与混凝土强度提高系数k之间的关系,得出了能有效约束核心混凝土横向变形的约束效应系数的有效范围,并确定了核心混凝土强度提高值与约束效应的关系,明确了钢管混凝土构件承载能力提高的原因。 引入第四强度理论（即形状比能理论）,分析钢管混凝土短柱的承载能力,建立了钢管进入塑性状态时的应力计算公式和核心混凝土的破坏准则,并确定了约束力与混凝土强度提高系数之间的关系,最终得出钢管混凝土轴心受压短柱的承载力计算公式。基于理论分析,进行了四组不同约束效应系数的钢管混凝土轴压短柱承载力的试验研究,试验结果与理论计算结果吻合较好。同时,通过对构件受力过程的分析,认为将构件的受力分为两个阶段即使用阶段和极限阶段,更为合理,并推荐了两个阶段的承载力计算公式,且计算结果基本能反映构件的工作状态,可用于指导工程实践。更多还原

【Abstract】 The concrete-filled steel tube (CFST) structure is a kind of composite structures, evolved and developed on the basis of steel reinforced concrete structure, spiral reinforced concrete structure and steel structure. Because of synergy of the two materials, the structure remedies their defects respectively and excellently improves its ductility and plasticity. With many unique advantages, the structure is widely applied to the constructional engineering.According to the characteristics of CFST structure and the problems which remain in practice, the article researches the CFST structure in four aspects, the constraining coefficient, the formula for calculating the ultimate capacity of the CFST short column、 the bearing behavior of mid-long column subjected to axial pressure and the anti-seismic behavior of CFST frame. The research achievement can be used as guidance for engineering design & practice.In the researching for the constraining coefficient about CFST, firstly, the raising coefficient of core concrete strength is analyzed. The relation between the constraining coefficient and the raising coefficient is established. According the relation, the effective range of the constraining coefficient is obtained, in which the lateral deformation of the core concrete can be effectively confined. The relation between the raising value of strength and the constraining coefficient is also determined.Based on the forth strength principle, the limit bearing capacity of the CFST short column subjected to axial pressure is analyzed, the formula for calculating the steel stress in plastic stage and the strength criterion of concrete under triaxial loading conditions have been established. According to the analysis of theoretical study, the limit bearing capacity formula of the CFST short column subjected to axial pressure is found. On the basis of the theoretical analysis, axial bearing components with four kinds of constraining coefficients are experimented. The theoretical values are in good accordance with experimental ones. By analyse of the components, it is shown that thelimit-bearing of the components can be divided into two stages, and calculating formulas of two stage are also recommended. The calculating formulas can be used to instruct parasitical engineering.The paper introduces two methods of calculating the limit bearing capacity of CFST mid-long column subjected to axial pressure, one is the tangent modulus and the other is the integration tangent modulus. The reaction between steel tube and core concrete is fully considered. On the basis of the theoretical analysis, fourteen samples with five kinds of long diameter ratio are studied experimentally. The testing conclusion accords well with the theoretical result, which is shown that the formula is fit for calculating the stable bearing capacity of mid-long column. When other conditions are same, the stable bearing capacity of CFST mid-long column is not reduced evidently along with the long diameter ratio increased. In the range of testing ratio, a stable coefficient is introduced which can be used for calculating the stable bearing capacity.Through the experiment with the two CFST frame structures under reversed loads, which have the same shapes, materials and dimensions, several parameters, such as stiffness, limit load, energy consume ability, were studied. By applying the extreme principle, the behavior of CFST frame structure is analyzed. Firstly, a collapse pattern of the structure is founded which is in good accordance with the experimental results, then the formula for calculating the load-bearing of the structure is established. The stiffness、 limit load and energy consume ability of the frame are studied, and the calculating methods of the stiffness is brought forward. From the contrast research, the CFST frame structures has many advantages, such as higher initial stiffness, higher load-bearing, good anti-seismic behavior and so on. By comparing theoretical value with experimental results, the former is fit well with the latter. The research achievemen更多还原