Based on the theory of equivalent tension rod for the thin steel plate shear wall

the improved capacity spectrum method was adopted by the finite element software SAP2000.The effect of storeys and spans on the response modification factor R

overstrength factor R

Ω

ductility reduction factor Rμunder moderate earthquake and displacement amplification factor Cdunder severe earthquake of moment resisting steel frame-thin steel plate shear walls designed by the shear capacity of plate was investigated by six examples.The results show that Rranges from2.55 to 2.81 similar to the 2.8125 that implied in Code for seismic des

ign of buildings

R

Ω

is from2.51 to 2.91

Rμranges from 0.9to 1.1under moderate earthquake and Cdis from 3.51 to 4.12 under severe earthquake.The influencing rule of spans on Rand R

Ω

isn′t obvious and the spans has almost no effect on R

μ

and Cd.The effect of storeys is very obvious

R and Rμunder moderate earthquake and Cdunder severe earthquake decreases with increasing storey

whereas R

Ω

increases with increasing storey.