Monitoring And Analysis Of Mechanical Performance Of Post-Wrapped Steel Tube Retrofitted RC Columns

Nowadays,the civil engineering community pays more and more attention to the reinforcement and reinforcement of reinforced concrete structures,which has promoted the continuous development of various reinforcement technologies.post-wrapped steel tube retrofitted RC(PSTRRC)column is a new type of reinforcement method.Based on the steel-clad method,the casing-constrained concrete method and the concrete-filled steel tube composite column,the working mechanism of concrete-like steel tube concrete is used to cut the original steel tube concrete.The outer layer of the column exposes the inner steel cage,and after welding the steel plate,it is welded to form the rear steel pipe,and the cavity is filled with grout to form a new combined structure.This method can maintain the function of the original structure without changing the cross-sectional dimensions of the original column,and can greatly improve the bearing capacity of the column,and its application prospect is extensive.Due to the lack of research and testing at this stage,its mechanical performance and theoretical system have yet to be improved.This paper combines the actual reinforcement and reconstruction project to study the mechanical behavior of post-concrete-filled steel tubular columns through long-term onsite monitoring and numerical simulation analysis.The main contents include:(1)Introduce the reinforcement design and construction plan and monitoring plan for post-concrete-filled steel tubular columns.(2)Select the three reinforcing columns in the basement of HuaXing Printing Highrise Building to track and monitor the whole process in the subsequent reinforcement construction process,and analyze the stress variation and distribution of each part in the combined section formed after reinforcement.The structural calculation software PKPM is used to establish the building model of the corresponding construction stage,and the internal force changes of the three monitored columns at different stages in the actual project are analyzed.(3)Using the finite element analysis software ABAQUS to establish post-concretefilled steel tubular columns model,simulate loading calculation according to different monitoring nodes,and combine the on-site monitoring results to reveal the change of the loading mode and stiffness,and study the combined column Axial force distribution,stress distribution,failure mode and ultimate bearing capacity during construction.(4)According to the results of monitoring and simulation,analyze the deformation of the combined section after reinforcement,and analyze the internal force increment of the post-reinforcement column according to the deformation coordination theory,that is,the force distribution mechanism according to the stiffness ratio of each part,and get Dual verification of on-site monitoring and numerical simulation.(5)Based on the current calculation methods of various steel-concrete composite columns and finite element analysis,analyze the bearing capacity of post-concrete-filled steel tubular columns and compare the internal force values of the components to judge the safety of the structure.