RESPONSE MODIFICATION FACTOR OF HIGH STRENGTH STEEL FABRICATED FRAMED-TUBE WITH REPLACEABLE SHEAR LINKS

High strength steel fabricated framed-tube structure with replaceable shear links (HSS-SFT) was proposed to improve the poor energy dissipation capacity and replicability after earthquakes. To investigate the response modification factor of HSS-SFTs, eight HSS-SFTs with ideal yield mechanism were established. The capacity curves of HSS-SFTs were obtained by stepwise lateral force adjustment method considering the effects of high-order vibration mode. The response modification factor R and displacement amplification factor C_d were obtained based on the improved capability spectrum method. Subsequently, the effects of parameters influencing R and C_d, including the building total story number and the shear link length, were investigated. According to the analysis results, HSS-SFTs have great overstrength and good ductility due to internal force redistribution of inelastic state. The R decreased, and C_d had no significant change as the total story number increased. The R and C_d slightly increased by an increase in the shear link length. Based on the analysis results, the R, R_Ω and the C_d equalled 3.65, 2.92 and 7.45 respectively and 30% elastic design earthquake action of HSS-SFTs can be approximately reduced though national seismic code. HSS-SFTs can characterize an ideal failure mode during rare earthquakes and effectively improve the poor energy dissipation and post-earthquakes repairable abilities of traditional steel frame-tube structure.