| It is evident from the observation of past earthquake hazards that the Well-designed building structures are able to withstand earthquake forces considerably larger than for what they are designed. This is due to the fact that the structures posses siginificant reserve strength and capacity, the reciproral influencing coefficient, namely seismic response modification factor, which is the reciprocal of C derived from General rule for performance-based seimic design of buildings, is being used to reduce the elastic response spectra of Single-Degree-Of-Freedom(SDOF) system under the fortification earthquake to obtain the structural design loads so as to calculate the seismic action according to linear elastic analysis in the existing seismic design codes.In general, the enengy dissipation capacity and overstength of structure is better, the seismic behaviour factor is greater and the corresponding base shear due to the seismic action is smaller. The reasonable seismic behaviour factor is directly relative to the safety and economy of designed structures.In the present, China code for Seismic Design of Building (GB50011-2001) take the same value (2.8125) of seismic influencing coefficient R in different structural systems, which will induce the different confidence levels and even make the some structures designed tend to be unsafe. So the good capacity of energy-disspation and ductiliy of steel structure cannot be used surfficiently according to the code. The single sway rod eccentrically braced steel frame structures as a dual lateral load resisting system with higher ductility and better energy dissipation capacity are gaining acceptance and suitable for multi-story or high-rise building in highly seismic regions. After carefully studying the papers about the seismic behaviour factor R, the paper adopts the method based on elastic-plasticty incremental dynamic analysis method for the structure influencing coefficients of single sway rod eccentrically braced steel frames.In this paper, the main contents of this dissertation are the following: Firstly, based on the China code for Seismic Design of Building (GB50011-2001), nine single sway rod eccentrically braced steel frame structures are designed and analyzed with selected seismic record by time-history method. Then their seismic behaviour factors are investigated. On the basis of the results, tentative seismic behaviour factor is proposed for single sway rod eccentrically braced steel frame structures.The seismic behaviour factor, ductility coefficient and over-strength coefficient of different storeys, spans, span numbers and period of frames on the behaviour factors, are investigated. Finally, the change rule of storeys, spans, span numbers and period of frames on the behaviour factors are given. |
