| Under strong earthquake, the structure has a certain capacity of ductility and energy-dissipation after being at the plastic stage. The modern seismic design theory discount the elastic response spectrum of seismic fortification intensity scale by the structural influencing coefficient R to obtain the action of structural seismic design, then design the structural by elastic design methods.Our country current"Code for Seismic Design of Building"(GB50011-2001) adopt the value (2.8125) of seismic influencing coefficient R which is based on the concrete structure in the way of"elastic design of small earthquake level". Compared with the concrete structure ,the design seimic base shear force of steel structure is not only lower for the good capacity of energy disspation and ductiliy,but also the force is larger for the lower damping value of steel structure, which isn't conducive to the development of steel structure.The inverted-V concentrically braced steel frame (CBSF) as a double system of lateral force has the advantages of overall stiffness and small moment of beam-column, which is more and more widely used in high-rise buildings system. In this paper,12 different stories and pans inverted-V CBSF are strictly designed according to Chinese design codes,the ductility reduction factor Rμ,the structural overstrength factor R?,the structural influencing coefficient R and the amplification factor of which are studied by incremental dynamic analysi(sIDA)method with ANSYS software to analyse the influence of stories,spans,cross,high-span ratio,fundamental period and spans of braced frames over the Rμ,R?,R and Cd,and propose the R and Cd value of the inverted-V CBSF. |
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