CFRP-钢复合管约束UHPC轴压短柱试验研究

Experimental study of the axial behavior of carbon fiber-reinforced polymer-steel composite tubes-confined UHPC stub columns

为研究纤维增强复合材料-钢管复合约束超高性能混凝土短柱的轴压承载力和变形性能,对9个纤维增强复合材料CFRP-钢复合管约束超高性能混凝土短柱、3个钢管约束超高性能混凝土短柱和2个芳纶布约束超高性能混凝土短柱进行了轴心受压试验。结果表明:碳纤维布-钢复合管约束超高性能混凝土短柱荷载-轴向变形曲线的形状与套箍系数有关,随着套箍系数增大,曲线形状依次呈现为抛物线形、双峰值形、多段线性形;峰值荷载时,当套箍系数ξ≤1.126,碳纤维布的断裂面积约为66.7%;当ξ>1.126,碳纤维布的断裂面积为34.8%;碳纤维布对于改善柱变形能力效果显著。最后根据试件实际约束强度,建立了碳纤维布-钢管复合管约束超高性能混凝土短柱的轴压承载力和峰值应变的计算公式,理论计算值与试验值吻合较好。

In order to study the axial compression strength and deformation of fiber reinforced polymer(FRP)-steel composite tube-confined ultra-high performance concrete(UHPC)columns,we did axial compression tests on 9 carbon FRP(CFRP)-steel composite tube confined UHPC columns,three steel tube-confined UHPC columns,and two AFRP fiber sheet-confined UHPC columns.The research results indicated that the shapes of the load-axial deformation curves of the CFRP-steel composite tube-confined UHPC columns are related to confinement factorξ,and with increasing confinement factor,the shapes of the curves are parabolic,double-peak bearing capacity,and multiple linear segments.Ifξ≤1.126,the CFRP fracture area was about 66.7%;whenξ>1.126,the CFRP fracture was about 34.8%under peak load;the deformation capacity could be improved significantly for specimens confined with CFRP.Based on the real restrain stress,we propose the formula for calculating the ultimate loading capacity and peak strain of CFRP-steel tube-confined UHPC.The results showed that the model is in good agreement with the experimental results.