Study On Structural Influence Coefficient Of K-shaped Eccentric Support Structure Of High Strength Steel

K-typed eccentrically braced steel frames with high strength steel combination refers to the links and braces using Q345 steel,frame beams and columns using Q460 high-strength steel,which has good ductility and lateral resistance.The plastic deformation is isolated to links to dissipate energy under rare earthquake.The structural influence coefficient R is an important factor in performance-based seismic design method for calculating base shear,ensuring structural safety and economic efficiency.The influence coefficient of K-typed eccentrically braced steel frames with high strength steel combination is not given in Chinese Standard.The influence coefficient R is studied in this paper.The specific work is as follows:Firstly,the K-typed eccentrically braced steel frames with high strength steel combination with different story(5 story,10 story,15 story,20 story)and the length of links(900mm,1000mm,1100mm,1200mm)is designed based on PBSD method,and each model are adjusted repeatedly according to the demand until all models meet the seismic requirements.Then,the finite element software SAP2000 is used to analyze each model.The load-displacement curve from pushover analysis is adjusted to the capacity spectrum curve,which intersects with the fortification seismic demand spectrum and the rare seismic demand spectrum respectively.And then,we could calculate the structural influence coefficient R and the displacement amplification coefficient Cd.The influence of the number of story N and the length of link e on the performance coefficient is analyzed.The results show that the structural influence coefficient and displacement amplification coefficient increase with the increase of story height and decrease with the increase of link length.Subsequently,the structural influence coefficient and displacement amplification coefficient of all prototype models by incremental dynamic analysis(IDA).Ten seismic records are choosing to nonlinear dynamic analyses,and adjusting peak acceleration to obtain a series of various strong earthquakes,including ordinary use lift safe and collapse prevention earthquakes,.The time history analysis of the structure is carried out,and the load-displacement curves of each prototype are obtained,and then the capacity spectrum is transformed,which can intersect with fortification seismic demand spectrum and rare seismic demand spectrum.Then the structural influence coefficient R and displacement amplification coefficient Cd are calculated,and the effects of the number of story N and the length of link e on the performance coefficient are analyzed.The results show that the structural influence coefficient and displacement amplification coefficient increase with the increase of story height and decrease with the increase of link length.Finally,by comparing the performance coefficients of all prototype structures calculated by the pushover analysis and IDA analysis,the relationship between the performance coefficients and the variation parameters(the height of the structure and the length of the link)is given.This paper provides design suggestions for seismic design of K-typed eccentrically braced steel frames with high strength steel combination.The numerical relationship between performance coefficient and fundamental period or ductility requirement is given,and the formula of structural influence coefficient R and displacement amplification coefficient Cd is obtained by linear correlation,which can provide reference for further research.