Study On Seismic Behavior Of External K-braced Steel Frame System

Prefabricated building means that most of the components of the traditional building are transferred to the factory to save labor cost.Since 2015,China began to vigorously implement prefabricated buildings.China is a large number of steel plants,and the advantages of steel structure construction are convenient,which makes the proportion of steel structure buildings in the building increase year by year.Therefore,the research of steel structure has more value and development prospect.There are many kinds of anti-seismic measures for steel structure.At present,steel frame structure with center support is mainly used to improve the anti-seismic performance of buildings at home and abroad.The central support in the structure can effectively improve the overall stability of the steel frame,but the architectural design and layout are limited;the failure of the internal support in the energy consumption stage will lead to the failure of the internal frame beam.This paper mainly studies the super high-rise braced steel frame structure,replacing the original structure with the built-in central support by the external K-braced support,building the structural model by using Midas building structural analysis software,comparing the seismic performance of the built-in central support steel frame structure with the external K-braced support steel frame structure,and comparing the different layout schemes of the external K-braced support steel frame system in the support Plastic analysis and dynamic time history analysis are used to compare the seismic performance of the structure.First of all,the mode decomposition response spectrum method is used to analyze the seismic response of the structure under the frequent earthquake action.The seismic response results of the structure are compared by the data of story displacement angle,story shear force,story overturning moment,displacement ratio and shear weight ratio of the supporting steel frame structure system.Secondly,pushover analysis method and dynamic time history analysis method are used to compare the seismic response and structural damage degree of structures under rare earthquake.In the seismic database of the Pacific earthquake engineering research center,10 seismic waves are selected for analysis.According to the data of the peak displacement time history,the base shear time history,the peak acceleration time history,the floor acceleration and so on,the yield mechanism,the weak link and the possible failure mode of the structure are compared.Finally,in the case of the same internal frame of the structure,four different situations of the external span width of 1 m,1.2 m,1.5 m and 2 m are analyzed,and the influence of different external span width on the seismic performance of the external K-braced support steel frame structure is studied.The research shows that the external k-brace can reduce the response of the structure to the earthquake,reduce the self weight of the structure and save the cost.The external K-shaped support can not affect the design and use of the internal space of the structure while it plays a supporting role and dissipates the seismic energy;after the support is damaged,the overall performance of the internal frame of the structure is not damaged and the support is easy to be replaced.The layout plan of the external K-shaped support steel frame only changes the support position in one direction,and the external K-shaped support is symmetrically arranged in the middle span,which can provide better seismic performance;when the external span width of the steel frame structure is 1.5m,the support plays the largest role.