CFRP布加固局部腐蚀圆钢管混凝土轴压短柱受力性能

Axial compressive behavior of CFRP-reinforced circular concrete-filled steel tubular stub columns with local corrosion

钢管混凝土目前已被广泛应用于各类建筑结构中,但是钢材存在易腐蚀的缺点,尤其是局部腐蚀。当钢管混凝土出现局部腐蚀时,其受力性能会有所退化,因此有必要对局部腐蚀后钢管混凝土的受力性能进行研究,并研究局部腐蚀后钢管混凝土的加固方法。为此,完成了7个圆钢管混凝土短柱的轴压试验,研究了机械开孔模拟局部腐蚀对圆钢管混凝土轴压短柱受力性能的影响,同时采用CFRP布加固机械开孔圆钢管混凝土短柱,研究CFRP布包裹层数对局部腐蚀圆钢管混凝土加固效果的影响。试验结果表明局部开孔会降低圆钢管混凝土短柱的轴压承载力、刚度和延性,且随着开孔长度的增加,降低幅度有所提高。采用CFRP布加固局部开孔圆钢管混凝土短柱能够提高试件的承载力,单层CFRP布加固时,试件达到极限荷载时CFRP布纤维突然断裂,试件延性较差;两层CFRP布加固时,试件的延性得到明显改善,整体加固效果更好,试件受力性能接近于未开孔的圆钢管混凝土。同时,采用ABAQUS软件建立了圆钢管混凝土有限元模型,并与试验结果进行了对比,验证了有限元模型的正确性。基于有限元分析结果,建议偏于保守地采用环向应力等于钢材屈服强度的计算方法等效计算CFRP布厚度,用于加固局部腐蚀圆钢管混凝土。

Concrete-filled steel tube(CFST)has been widely used in various kinds of buildings and structures,but steel has the disadvantage of easy corrosion,especially the local corrosion.When local corrosion occurs on CFSTs,the mechanical performance of CFSTs will degrade,so it is necessary to study the axial compressive behavior of CFSTs with local corrosion and the reinforcement method.Seven circular concrete-filled steel tubular stub columns were tested under axial compressive loads to study the influence of simulated local corrosion on axial compressive behavior.And the influence of different carbon fiber reinforced polymer(CFRP)layers on the strengthening effect of CFRP-reinforced mechanical open-hole circular CFST was studied.The results show that the local notch has an obvious effect on the behavior of the specimens,and the reduction amplitude of the bearing capacity,stiffness and ductility increases with the increase of notch length.CFRP improves the bearing capacity of the circular concrete-filled steel tubular stub columns with notch.When there is only one layer of CFRP,the CFRP breaks suddenly when reaches the ultimate load,and the ductility of specimens is poor.However,when the CFRP is increased to 2 layers,the ductility of specimens is improved,and the reinforcement effect is better.The behavior of the specimen is similar to that of the circular CFST without notch.Furthermore,the finite element models were established by ABAQUS software and the accuracy was validated by comparing with the experimental results.Based on the analysis of CFRP-reinforced circular CFST,it is recommended that the calculation method of hoop stress equal to the steel yield strength can be used conservatively to calculate the equivalent CFRP thickness for the reinforcement of local corroded circular CFST.