外包钢板-混凝土组合连梁试验研究(Ⅰ):抗震性能

Experimental research on concrete filled steel plate composite coupling beams(Ⅰ) : seismic behavior

对6根外包钢板-混凝土组合连梁试件进行了拟静力加载试验,试件变化参数有连梁跨高比、钢板厚度和弯剪比。连梁钢板的破坏包括连梁端部钢板的开裂和钢板的局部屈曲。试件承载力的下降主要由梁端钢板的开裂和裂口扩展引起。所有试件的连梁钢板开裂后,裂口迅速扩展,在钢板开裂或开裂后的下一级位移循环时荷载达到峰值。连梁钢板的局部屈曲分为连梁端部钢板的受压局部屈曲和钢腹板的剪切局部屈曲。局部屈曲的发生和形态主要受钢板厚度、连梁的跨高比和钢板开裂的影响。所有试件的内填混凝土均未发生明显的受压破坏。混凝土的开裂程度与裂缝分布与外部钢板的变形程度相一致。采用连梁钢腹板无对接焊缝构造试件的变形能力明显优于连梁钢腹板有对接焊缝构造试件的变形能力。所有试件的滞回曲线饱满,具有稳定的耗能能力。

Six concrete filled steel plate composite coupling beam specimens were tested under cyclic loading. The variable parameters were span-to-height ratio,steel plate thickness and flexure-to-shear capacity ratio. The failure modes of the steel plates include the fracture of the steel plates at beam ends and local buckling of the steel plates. The fracture and fracture propagation were the main factors that caused the loss in shear capacities of the coupling beams. The fracture propagated fast after fracture initiated,and the shear capacities began to degrade in no more than one displacement level. Two local buckling phenomena were observed including compression local buckling at the beam ends and shear buckling of the steel webs. The occurrence and form of local buckling was affected by the steel plate thickness,span-to-height ratio,and fracture of steel plates. Concrete compression failure was not observed in the infill concrete for any of the specimens. The concrete crack patterns were consistent with the deformation of steel plates. The deformability of the specimens without butt weld of the steel webs is evidently better than that of the specimens with butt weld. The hysteretic curves of all the specimens are plump,indicating stable energy dissipation capacity.