초록
The seismic overstrength factor $\Omega$ is evaluated for 4-story reinforced concrete buildings in Korea(of which seismic intensity is low). The study model is designed according to aseismic guideline research - phase II in Korea. The effect of variation of span length and bay number, dead load is considered, especially including the variation of hardening ration after yielding. And push-over analysis is performed, in which the external and internal frame is connected by rigid-link and the $\Omega$ is calculated using the roof drift ratio at 2%. For Zone I, the mean value of $\Omega$ is ranged form 2.3 to 2.5, For Zone II, from 3.1 to 3.4. For low hardening ratio(3%) after yielding, $\Omega$ has little relations with the number of bay, like as the results of other research. But for 5% hardening ratio, $\Omega$ is increased as the number of bay is increased. Within general gravity-load bound, the variation of D.L. has variation of D. L. has no effect on $\Omega$. And, $\Omega$ is increased as the span length is increased.
