Strengthening Design And Seismic Performance Analysis Of Concrete Frame Structure With Removing Columns

With the rapid development of China’s economy,the production and lifestyle of people have undergone tremendous changes,The requirements for architecture were getting higher.Due to the constraints of design functions,old buildings need to be strengthened to satisfied people’s requirements.removing columns and expanding spans is a new method under the requirements for building space.Based on specific engineering,this article analyzes the result of the structure before and after removing columns,and research the influence of concrete frame structure with removing columns.The main research content of the project lists as follows:(1)The technology of removing columns and strengthening structure was summarized,the advantages and disadvantages of various methods and areas of applications were analyzed.(2)An concrete frame structure were analyzed with software of PKPM and SAP2000.In order to improve Stiffness of beam by gradually increasing the height of the beam section.We chose a beam section with a size of 600mmx 1750mm.The strengthening methods of frame beams,columns,respectively.The reinforcing bars of beams were calculated.The influenceof the surrounding columns after removing column was analyzed,4 columns around the extracted column with section enlargement,6 columns on both sides of the removing column with steel-encasing strengthening.(3)Based on the five basic assumptions,the flexural members were reinforced under tension,the development process of tension steel strain and compression steel strain were calculated,respectively,when the concrete strain was in ε≤ε0,ε0≤ε and ε=εcu.The yield curvature and ultimate curvature of the flexural member were obtained.The flexural members were reinforced under tension and compression,the relationship were analyzed between the original reinforcement and the new reinforcement.(4)According to the formula deduction and Pushover method,the structure were analyzed of before and after removing columns.The Inter-Story Displacement Angle Ratio,Floor shear and development of plastic hinge of frequently occurred earthquake and rarely occurred earthquake were compared.The Inter-Story Displacement Angle Ratio was all smaller than the Chinese standard.Plastic hinges appeared at the beam first,then develop to the all column after the beam ends appeared,finally,we develop the column in line with the"strong column and weak beam" mechanism(5)Three seismic waves were selected to analyze the structure before and after removing column with Dynamic Time-history Analysis,the Inter-Story Displacement Angle Ratio,Vertex displacement and Floor shear were compared.The seismic performance of the structure was verified after removing column.