钢管高性能混凝土轴压短柱的静力性能(Ⅱ):机理分析及承载力

STATIC PERFORMANCE OF THE HIGH-PERFORMANCE CONCRETE FILLED STEEL TUBULAR STUB COLUMN(Ⅱ): MECHANISM ANALYSIS AND LOAD BEARING CAPACITY

研究钢管高性能混凝土轴压短柱中钢管和混凝土的应力、应变等的分布规律,发现圆试件中截面混凝土纵向应力在圆周方向均匀分布,而方试件中截面混凝土的纵向应力在弯角处最大。试件在受荷过程中,中截面钢管首先屈服,然后逐渐向试件两端发展。典型算例的分析结果表明,圆钢管对混凝土的约束作用好于方钢管的,圆钢管对混凝土沿圆周方向均匀约束,而方试件在截面弯角处的约束力最大。所有试件在中截面约束力最大。黏结强度对于试件的轴压承载力基本没有影响。普通钢管混凝土轴压短柱的承载力计算式同样适用于钢管高性能混凝土轴压短柱的承载力计算。钢管高性能混凝土轴压短柱与普通钢管混凝土轴压短柱在静力性能方面并无本质区别。

Distributions of stresses and strains of steel tube and concrete for high-performance concrete filled steel tubular stub column were investigated, it was found that longitudinal stress of concrete at mid-height cross-section distributed uniformly around the circumferential direction for the circular specimen, while longitudinal stress of concrete at mid-height cross-section located at corners was the biggest one for the square specimen. During loading process, steel tube at mid-height cross-section yielded firstly and then yield region developed gradually toward the two ends of the specimen. Analysis results of the typical calculations indicated that the circular steel tube could provide better confinement for concrete than the square steel tube, also, the circular steel tube confine the concrete uniformly around the circumferential direction while the confinement forces located at corners were the biggest ones for the square specimen. All of the specimens had the biggest confinement forces at the mid-height cross-section. Adhesive strength had little influence on the load bearing capacity of the specimens. Calculation formula of load bearing capacity for the normal concrete filled steel tubular stub column is also suitable for the high-performance concrete filled steel tubular stub column. There are no essential differences between the high-performance concrete filled steel tubular stub column and the normal concrete filled steel tubular stub column in aspect of static performance.