Finite Element Analysis Of High-Rise Frame Structures With Storey-Adding And Research On Methods Of Reinforcement

Nowadays,the land for urban construction is getting increasingly tense as the rapid development of urbanization in China.In order to increase the usable area of building to relieve the pressure of land demand,the technology of storey-adding rebuilding has been widely applied in our dailylife.In this paper,combined with the engineering practice that tested and reinforced to meet the needs of adding stories,the content of structural inspection and identification both with the reinforcement methods which were commonly used were introduced in great detail.PKPM was used to model and analysis buildings with storey-adding before and after reinforcement.For the members that did not meet the requirements of the code,different reinforcement schemes were proposed.In order to compare and evaluate the reinforcement effect,so as to provide reference for similar projects.ABAQUS was used to simulate and analyze the frame columns strengthened by different methods.The main work of this paper is as follows:1.The common reinforcement methods of buildings and their advantages,disadvantages and application scope were summarized systematically,at the same time,the present situation of reinforcement research at home and abroad was summarized.In the background of a concrete high-rise frame structure with storey-adding,the content of building inspection and appraisal was described in great detail.In order to provide basis for the design of structural reinforcement and reconstruction,the engineering quality of an existing structure was tested and appraised on the spot.2.PKPM was used to model and calculate the whole structure with storey-adding.The parameters such as axial compression ratio,storey drift ratio,shear-weight ratio,composite index of the ability of anti-seismic,natural vibration period and the effective mass ratio were analyzed to verify that the original structure needs to be strengthened before adding storeys directly.Combined with the inspection and appraisal conclusions,three reinforcement schemes of frame columns are proposed.The first one is the method of increasing cross-section;the second one is the method of externally bonded steel;the third one is the method of increasing cross-section in basement,and the other layers use method of externally bonded steel.In the meantime,the cracks in the floor slab are strengthened by pasting carbon fiber.The whole model of the structure strengthened by different schemes is established by JDJG model of PKPM,then the mechanical indexes of the structure before and after reinforcement are compared to evaluate the overall reinforcement effect of different schemes.The results show that all the parameters of the structure meet the requirements of the code after strengthened with different schemes.In addition,the method of increasing cross-section has the best effect on the bearing capacity and the resistance to deformation of the structure,while the method of composite reinforcement has the most significant effect on the seismic performance of the structure.3.Finite element models of columns under different reinforcement schemes were established by ABAQUS,then the parameters such as the displacement of columns,PEEQ of concrete and MISES of steel were compared to evaluate their strengthening effect of columns.The results show that the columns strengthened with increasing cross-section have better resistance to damage,deformation and bearing capacity than the columns strengthened with externally bonded steel.In contrast,the seismic behavior of externally bonded steel columns is better than that of reinforced columns with enlarged sections.Through the comparison of the overall reinforcement effect and local component reinforcement effect of different schemes,combined with the actual factors,the reinforcement scheme of adding storeys is optimized,and the composite reinforcement method is adopted finally.