| Steel structure building has remarkable advantages such as high strength,light weight,energy saving and environmental protection.Steel structure is more and more widely used and developed in civil engineering.However,in the process of design,construction and subsequent use of steel structures,various reasons may cause different degrees of damage to them,which will affect the stability of the structure and cause huge losses to people's safety and economy.As an economical and efficient reinforcement method,CFRP reinforcement technology has gradually become a research hotspot.However,the research on CFRP strengthening compressive steel members is still in its infancy.Based on this background,the following aspects are mainly studied in this paper:(1)Referring to the relevant clauses of “strengthening metallic structures using externally bonded fibre-reinforced polymers” compiled by CIRIA and the current steel structure design standards in China,the formulas for calculating the stable bearing capacity of reinforced steel structural member are established.(2)The supplementary experimental study of compressed circular steel columns strengthened with CFRP was carried out by setting 5 circular steel tube specimens(including 1 unreinforced contrast specimens and 4 specimens strengthened with CFRP).Combined with relevant experimental data in the previous period,the effects of eccentricity,CFRP layer and structural measures on the bearing capacity and failure mode of CFRP-reinforced compressed circle tubular steel columns were studied.(3)The establishment process of ABAQUS finite element model is described in detail,including material constitutive relationship,element type selection,contact relationship definition,load and boundary conditions,meshing,introduction of initial defects,and non-linear solution method.(4)The finite element model of the supplementary experiment was established by using ABAQUS software,and the simulation results were compared with the experimental results to verify the validity of the model.Based on the model,the numerical analysis of orthogonal design method is used to compare the effects of eccentricity,CFRP layer and slenderness ratio on the stable bearing capacity of CFRP-reinforced circular tubular steel columns.Combined with the finite element simulation results of the orthogonal design,the modified coefficient of the formula of the stable bearing capacity is deduced.Finally,the calculation formula for the ultimate stability bearing capacity of CFRP-reinforced compressed circular tubular steel members with modified coefficient is proposed.This subject is supported by national standard “Design code for strengthening steel structure” and the research findings of this paper will provide theoretical and experimental bases for writing this standard. |
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