Field Monitoring And Finite Element Simulation Analysis Of Frame Structure Under Column Removal Scenario

In this paper,a top-floor column-removal reconstruction project in four-story reinforced concrete frame structure is introduced and researched.A series of tasks about this project are carried out,consisting of remodeling design,construction design,on-site monitoring design and finite element simulation by ABAQUS.These work provide references for the application of enlarging cross-section method in large-span column-removal reconstruction project.The specific work and results in this paper are as follows:(1)The background of the reconstruction and reinforcement of structures are summarized and described comprehensively,and the development prospects of the reconstruction and reinforcement industry is emphasized which point out the significance of this research.This paper summarizes five column-removal underpinning techniques,including enlarging cross-section method,prestressing method,suspending by conversional beam method,additional internal supporting frame method and truss bracing method,which are compared and analyzed from the perspective of underpinning principle,range of application and current state of research.These work provide references for the selection of underpinning method under column-removal scenarios.(2)Several reconstruction and strengthening methods are compared in a real 18m large-span column-removal project,which draw a conclusion that enlarging cross-section method is more effective and economical.Analyze and emphasize the importance of the stress system transformation.(3)Strain and displacement data of the main frame beam during five-stage unloading process are obtained by on-site monitoring system,which records both the overall stress transforming trend and the final stress state of the beam.According to the monitoring data analysis,the rationality of reconstruction design is obtained.The structure is elastically developed under the first four stages of unloading and plastic deformation occurs at the fifth stage of unloading.It is speculated that the continued loading may further induce the catenary effect.(4)The overall stress state of reinforced structure after column-removal is studied through finite element simulation by ABAQUS.Through the analysis of finite element material parameters,element type and mesh quality,the optimal modeling method suitable for this project and similar engineering analysis is obtained.Meanwhile Compare with the on-site monitoring results and simulation results,and the conclusion is drawn that the structural internal force development trend is consistent.