配螺旋箍筋方钢管混凝土柱计算方法及试验研究

发布时间：2019-05-07 05:10

【摘要】：方钢管混凝土柱中钢管边中部对核心混凝土的约束较弱，使得方钢管混凝土柱中核心混凝土的抗压强度不能得到充分发挥。为了充分发挥方钢管混凝土柱中核心混凝土抗压强度和塑性变形能力，在方钢管混凝土柱中配置螺旋箍筋来有效约束核心混凝土，从而提高方钢管混凝土柱的承载力和塑性变形的能力。因此，本文通过试验研究了方钢管混凝土及配螺旋箍筋方钢管混凝土柱的力学性能和破坏模式，及方钢管混凝土及配螺旋箍筋方钢管混凝土柱承载力的计算方法。通过试验研究结果表明：相对方钢管混凝土柱而言，配螺旋箍筋方钢管混凝土柱承载力有较大程度的提高，最大提高幅度为41％；由于螺旋箍筋对核心混凝土的约束作用使得配螺旋箍筋方钢管混凝土柱的横向应变小于方钢管混凝土的横向应变；配螺旋箍筋后使得方钢管对核心混凝土的约束效应增强，配螺旋箍筋方钢管混凝土柱的上部到下部截面横向应变比方钢管混凝土柱变化均匀；相对于增加螺旋箍筋直径来说，，减小螺旋箍筋间距可更有效的增加配螺旋箍筋方钢管混凝土柱的极限承载力和延性。在钢管混凝土柱计算方法中，叠加理论计算公式简单明了，容易在实际工程中采用。但方钢管对核心混凝土的约束效应对承载力的影响在叠加原理中并未得到体现。因此本文研究的计算理论主要以叠加理论为基础，通过把方钢管混凝土柱的核心混凝土分为有效约束区和非有效约束区，对有效约束区的核心混凝土采用有侧向约束的强度，来考虑钢管的约束效应对方钢管混凝土柱承载力影响的计算方法，并将有效约束区、非有效约束区和方钢管三部分的承载力相互叠加，推导出方钢管混凝土短柱的承载力计算公式。通过相同的方法将配螺旋箍筋的方钢管混凝土柱的核心混凝土分为三部分：方钢管和螺旋箍筋共同作用的有效约束区、单独螺旋箍筋作用的有效约束区和非有效约束区，并将方钢管和螺旋箍筋共同作用的有效约束区、单独螺旋箍筋作用的有效约束区、非有效约束区和方钢管四部分的承载力相互叠加，推导出配螺旋箍筋的方钢管混凝土柱的承载力计算公式。通过将方钢管混凝土柱等效为圆钢管混凝土柱，并将极限平衡理论首次应用在方钢管混凝土柱的承载力计算中，按照上述方法把核心混凝土分为有效约束区和非有效约束区，通过钢管的Von Mise屈服条件和方钢管混凝土柱的承载力的平衡条件，推导得出方钢管混凝土柱的理论计算公式。
[Abstract]:The compression strength of the core concrete in concrete filled square steel tube column can not be fully exerted because of the weak constraint on the core concrete in the middle edge of the concrete filled square steel tube column. In order to give full play to the compressive strength and plastic deformation capacity of core concrete in concrete filled square steel tube columns, spiral stirrups are arranged in concrete filled square steel tube columns to restrain the core concrete effectively. Therefore, the bearing capacity and plastic deformation ability of concrete filled square steel tube columns are improved. Therefore, the mechanical properties and failure modes of concrete-filled square steel tube (CFST) and concrete-filled square steel tube (CFST) columns with spiral hoop reinforcement, as well as the calculation methods of bearing capacity of CFST and CFST columns with spiral hoop reinforcement, are studied experimentally in this paper. The experimental results show that the bearing capacity of concrete-filled square steel tube columns with spiral hoop reinforcement is improved to a great extent, and the maximum increase is 41%. The transverse strain of concrete filled square steel tube column with spiral hoop reinforcement is smaller than that of concrete filled square steel tube due to the constraint of spiral stirrups on the core concrete. When reinforced with spiral stirrups, the restraint effect of concrete filled square steel tubes on the core concrete is enhanced, and the transverse strain of concrete filled square steel tube columns with spiral hoop reinforcement, such as the lateral strain of the concrete filled steel tube columns, varies evenly from the upper to the lower section. Compared with increasing the diameter of spiral stirrups, decreasing the spacing of spiral stirrups can increase the ultimate bearing capacity and ductility of concrete-filled square steel tube columns with spiral stirrups more effectively. In the calculation method of concrete filled steel tube column, the calculation formula of superposition theory is simple and clear, and it is easy to use in practical engineering. However, the influence of the restraint effect of square steel tube on the bearing capacity of core concrete is not reflected in the superposition principle. Therefore, based on the superposition theory, the core concrete of concrete filled square steel tube column is divided into effective constraint zone and non-effective constraint zone, and the strength of the core concrete with lateral constraint is adopted for the effective constraint zone. Considering the constraint effect of steel tube to the bearing capacity of concrete-filled steel tube column, the bearing capacity of three parts, namely effective restricted zone, non-effective confined zone and square steel tube, is superimposed on each other. A formula for calculating the bearing capacity of concrete filled square steel tubular short columns is derived. In the same way, the core concrete of concrete filled square steel tube columns with spiral stirrups is divided into three parts: the effective binding zone of square steel tube and spiral stirrups, the effective binding zone of single spiral stirrups, and the non effective confinement zone of the concrete filled square steel tube columns with spiral stirrups. The effective restraint zone of square steel pipe and spiral stirrups, the effective restricted zone of single spiral stirrups, the non-effective restricted zone and the bearing capacity of square steel pipes are superimposed on each other. A formula for calculating the bearing capacity of concrete-filled square steel tube columns with spiral stirrups is derived. The concrete filled square steel tube column is equivalent to the circular concrete filled steel tube column, and the limit equilibrium theory is applied to the calculation of the bearing capacity of the square concrete filled steel tube column for the first time. According to the above method, the core concrete is divided into effective constraint zone and non effective constraint zone. Based on the Von Mise yield condition of steel tube and the equilibrium condition of bearing capacity of concrete filled square steel tube column, the theoretical calculation formula of concrete filled square steel tube column is derived.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU398.9

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