The objectives of this paper are firstly to propose the reducing rate due to opening effect for estimating the slip shear strength of the shear wall with various kinds of openings, and secondly to examine its validity. The proposed reducing rate γ_u is expressed as follows, γ_u=√<(ΣAe)/(hl)>・・・・・・・・・・・・・・・・・・(1) In order to examine the validity of proposed reducing rate γ_u, the experimerits were carried out by speocimens having various kinds of openings when the walls fail in shear. The strength calculated by using Eq. (1) was compared with authors' and other researchers' experimental results. It was recognized that the results are very much in agreement with experimental results. Eq. (1) is limited to the shear walls with openings when the walls fail in shear.
