Experimental Research On Local Stability Of CFRP Reinforced Axially Compressed Square Steel Short Columns

Steel construction is a new type of energy saving and environmental protection structural system.It is praised as the “green building” in the 21 st century.Its advantages of light weight,large span,energy saving,environmental protection,and ability to be recycled make steel structures widely used in modern economic construction of China.However,corrosion,overload,or disasters may affect the safety of the structure in the long-term of using steel structures.Therefore,how to reinforce and repair steel structures has always been an important issue in the field of civil engineering.As a kind of reinforcement method with unique advantages,CFRP reinforcement and repairing steel structure technology has become a research hotspot for domestic and foreign scholars in recent years.At present,scholars at home and abroad have studied the stability of CFRP-reinforced eccentrically compressed steel tubular columns,but few studies have been conducted on the stability of axially compressed square tubular steel columns.Therefore,in view of the deficiencies in the current stage of research,this article has carried out the experimental study on the local stability of axially-pressed square steel pipe short columns.In this paper,24 CFRP-reinforced axial compression square tubular steel short column tests were conducted.The study is as follows:(1)Study on the Failure Mechanism of Local Destabilization of Axially Loaded Square Steel Short Column.(2)Study on the effect of width-to-thickness ratio on the failure mode of opposing steel pipe stubs.(3)Study on the reinforcement mechanism of two reinforcement directions of CFRP vertical and ring attachment.(4)Studied the influence of the slenderness ratio on the improvement of the ultimate bearing capacity when the square steel pipe columns adopt different reinforcement directions,and obtained the quantitative analysis results that can be used for engineering design.(5)The ANSYS software was used to establish the "shell-spring-shell" finite element analysis model,and the model calculation results were compared with the test results to verify the accuracy of the test and the validity of the finite element analysis model.The research content of this paper provides theoretical analysis and test basis for the newly compiled national standard "Code for Strengthening Design of Steel Structures" and related engineering design methods.