内置复材约束的T形截面钢管混凝土组合柱轴压力学性能试验研究

Experimental study on axial compression performance of T-section concrete filled steel and FRP tubular composite columns

  • 摘要: 内置复材约束的T形截面钢管混凝土组合柱(T-section concrete filled steel and GFRP tubular composite column,T-SCFC)包括外部钢管、夹层混凝土、玻璃纤维增强树脂复合材料(Glass fiber reinforced polymer,GFRP)管和核心混凝土。对14根不同截面形式的约束混凝土短柱和3组内置不同复材管壁厚的T形截面钢管混凝土组合柱进行轴压试验,对比分析了方钢管混凝土短柱(Square concrete filled steel tube,CFST)、复材管约束混凝土短柱(Concrete filled GFRP tube,CFFT)、内置复材约束方钢管混凝土短柱(Steel-concrete-GFRP-concrete tube,SCFC)和T-SCFC柱在轴压荷载作用下的力学性能。建立与试件同尺寸的有限元模型,并开展数值参数分析,研究不同钢管壁厚和核心混凝土强度对T-SCFC柱轴心受压性能的影响。结果表明:内置约束复材管可以明显提高方钢管混凝土短柱的受压性能,显著延缓SCFC短柱在轴压荷载作用下的钢材屈服和鼓曲;T-SCFC柱在达到峰值荷载前,荷载-轴向位移曲线呈双线性增长,复材断裂后试件保持较高的残余承载力呈延性破坏,可以将复材断裂作为该类组合柱的失效点,增加复材管壁厚可以明显提高试件承载力;有限元模型计算结果与试验吻合较好;增加钢管壁厚可明显提高试件的承载力,提高试件核心混凝土强度仅对试件的等效屈服荷载有一定提高作用,对试件峰值承载力的影响较小。

     

    Abstract: The T-section concrete filled steel and glass fiber reinforced polymer (GFRP) tubular composite column (T-SCFC) is composed of external steel tube, sandwich concrete, GFRP tube and core concrete. Axial compression tests were carried out on 14 confined concrete short columns with different cross-section forms and three groups of concrete-filled steel tubular T-section columns with different wall thicknesses of GFRP tube. The mechanical properties of square concrete filled steel tube (CFST), concrete filled FRP tube (CFFT), steel-concrete-FRP-concrete (SCFC) short columns and T-SCFC columns under axial compression were compared and analyzed. The finite element model with the same size as the specimen was established, and the numerical parameter analysis was carried out to study the influence of steel tube wall thickness and core concrete strength on the axial compression performance of T-SCFC columns. The results show that the built-in GFRP tube can significantly improve the compression performance of concrete filled square steel tubular short columns, and significantly delay the steel yield and buckling of SCFC short columns under axial compression load. Before the peak load, the load-axial displacement curve of T-SCFC column increases bilinearly, and the residual bearing capacity of the specimen maintains high after fracture of the GFRP. The fracture of GFRP can be used as the failure point of the composite column. Increasing the wall thickness of GFRP tube can significantly improve the bearing capacity of the specimen. The calculation results of the finite element model are in good agreement with the test. Increasing the wall thickness of the steel tube can significantly improve the bearing capacity of the specimen. Improving the strength of the core concrete of the specimen only has a certain effect on the equivalent yield load of the specimen, and has little effect on the peak bearing capacity of the specimen.

     

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