Elastic-plastic Analysis Of Influence Of Bottom Columns' Damage On Overall Structure Performance

Our country takes much account of repairing the damage of building structure work particularly seriously in recent years,many local building structures get damaged but can still go into service after identification and reinforcement of local damaged members.However,lots of research has concentrated on analysis of local members' failure on continuous collapse resistance of structure,the research on single member's damage is rare.Therefore,what this paper studies on is the impact of damaged columns on overall structure performance after injury and repair reinforcement of bottom columns of frame structure under circumstance that overall structure is at normal service,which has an important practical significance.This article takes residential buildings(high rise RC frame structure)of a uptown in Nanjing as study objection.Research are carried out according to different working conditions of damaged middle columns,corner columns and side columns:1)Uniaxial constitutive relation of containing material failure principle of reinforcement and concrete is defined based on subroutine UMAT of finite element software ABAQUS,and the material constitutive relation that is suitable for this engineering structure is determined through uniaxial tension and compression tests of RC constitutive column and repeated load-unload hysteresis tests.2)The static nonlinear analysis method is used to study the influence of local members' damage and repair in different working conditions on overall frame structure performance,interlaminar maximum node displacement,interlaminar maximum shear force and bending moment,plastic deformation and damage of RC beam members in serviceability limit state and bearing capacity limit state respectively are obtained,compared with whole model and analyzed.3)Seismic performance indicators are determined according to the performance-based design thought.Time history analysis of rare earthquake is done to repaired structure model,and the base shear force,shear-weight ratio,interlaminar displacement angle,vertex displacement and plastic deformation and damage of RC beam members when structure is under strong earthquake are obtained,comprehensive performance evaluation and analysis of single member's damage of structure system are finished according to scheduled performance indicators.Results show that corner column's damage of bottom structure has a greater effect on overall structure,side column and middle column take the second place.Bottom diddle columns' damage and repair has a greater impact on surrounding members,compared with longeron,yield area of transbeam is larger,and the plastic damage is more serious.The adjacent beam should be strengthened after damage of bottom columns,and the adjacent beams of the bottom and top are very important.Under the effect of different seismic waves,repaired structure model can still meet requirement of earthquake-resistance design,which validates the feasibility that damaged structure can keep normal service after repair and reinforcement.