Research On The Storey-adding Reinforcement And Seismic Performance Of A Steel Frame Structure

With the improvement of people’s requirements for the application function of buildings,the reinforcement and reconstruction of existed structure have gradually entered the public view.Through this practice,the application function of buildings has been improved,and a new upsurge has been set off in the industry.Steel frame construction is an efficient and environmentally friendly buildings structure,which has been quick development since it was appeared.At present,Our country’s steel construction is in the stage of large-scale construction,a large number of such buildings will need to be added and reinforced in the future.Therefore,it is urgent to explore the steel construction storey-adding and reinforcement technology for our country.This thesis takes an irregularly-shaped exhibition hall as a specific engineering example,and based on the existing steel frame structure’s existing store-adding reconstruction code and seismic code,the original structure is reinforced with storeys,and the safety before and after the strengthening of the storey structure under different earthquakes is discussed,To verify the effectiveness of reinforcement scheme.The main research contents of this thesis include:(1)Verify the bearing capacity of the structure after direct layer addition.Choose the appropriate detection method to detect the original steel frame structure material and structural distortion,using the structural analysis and design software PKPM established the steel frame structure model after add layer directly.The analysis found that the bearing capacity of some steel columns in the added-storey structure is insufficient,and some steel beams have too much deflection,and the overall seismic performance of the structure unable contented the specified requirements.According to the seismic requirements,appropriate reinforcement methods are selected to reinforce the structure after adding floors according to seismic requirements.(2)Explore the dynamic characteristics before and after structural reinforcement.The finite element software SAP2000 is used established the analysis model before and after reinforcement.It is found that the natural vibration period of the structure decreases and the overall stiffness of the structure increases after reinforcement.The response spectrum method and time history analysis method were used to study the structural displacement and base shear changes before and after reinforcement under various seismic conditions were compared to evaluate the seismic performance and reinforcement effect of the structure before and after reinforcement under frequent earthquakes.(3)The seismic response of the structure before and after reinforcement under three kinds of seismic waves under rare earthquakes is studied,and the development of structural plasticity and structural safety after reinforcement are discussed.The nonlinear time history analysis method is used to verify the seismic performance of the structure under rare earthquakes.Result indicates that the structure before reinforcement does not meet the seismic requirements under the selected seismic waves,and the reinforced structure can meet the seismic requirements under various seismic waves.The location and development of structural plastic hinges under rare earthquakes are explored.After reinforcement,the structural plastic hinges are all in the life safety stage,and the structure has good seismic performance,which meets the basic requirements of seismic fortification in China.(4)Design the additional storeys of the plane irregular steel frame structure different from the original structure,strengthen the structure after adding storeys,study the seismic capacity of the added storey structure before and after strengthening,put forward relevant design opinions,and provide reference for the design of similar projects structures.