| Near-surface-mounted(NSM)technique is an effective strengthening method.The existing research results mainly focused on beams,plates and seismic columns.There were few studies on the reinforced concrete(RC)columns strengthened with NSM hign-strength aluminum alloy(AA)bars under eccentric compression.High strength aluminum alloy is a new type of strengthening materials after fiber-reinforced-polymers(FRP).Which had some advantages of good ductility,strong plasticity,high strength and light weight,and can be use in special environment.Therefore,it had good potential in the practical application of bridges,large-span spatial structures and the strengthening for concrete structures.In this paper,16 RC columns strengthened with NSM high-strength AA bars were designed and manufactured,and the eccentric compression tests,numerical simulations and theoretical analysis were carried out to provide theoretical basis and design suggestions for the application of RC columns strengthened with the NSM technique using AA bars.The main research contents of this paper are as follows:(1)The experimental study on the eccentric compression behavior of RC columns strengthened with NSM high-strength AA bars was carried out.The eccentric ratio,reinforcement amount and CFRP wraps were selected as experimental variables.The experimental phenomena,failure progress,bearing capacity,strain development,displacement ductility and strain distribution in cross section of RC columns strengthened with the NSM technique using AA bars were analyzed.(2)A three-dimensional finite element model of RC columns strengthened with NSM highstrength AA bars under eccentric compression was established,and the accuracy of the numerical model was verified.Based on the model,the effects of eccentric ratio,reinforcement amount and layers of CFRP wraps on the eccentric compression properties are studied.Based on the numerical model,the mechanism of whole failure progress of specimens was analyzed,including the load-lateral deflection curves,the stress development of the concrete,and the stress development of the steel bars and the AA bars.(3)Based on the strain distribution laws in the cross section of RC columns strengthened with NSM AA bars,the theoretical analysis was carried out.A calculation model of bearing capacity for the RC columns strengthened with NSM AA bars was established and verified.(4)According to the experienmental and theoretical calculation results,the N-M correlation curves of NSM AA-strengthened columns are drawn and analyzed.The analysis results showed that the eccentric compression properties of the RC columns using the NSM AA strengthening method were significantly improved,and the flexural capacity of the specimens was significantly improved. |
