鉄筋コンクリート耐震壁のせん断耐力に関する研究

抄録

The ultimate shear capacity of reinforced concrete shear walls has been studied theoretically and experimentally by many researchers. However, it is difficult to estimate reasonably the ultimate shear capacity of'shear walls, because of the complexity in the failure mechanisms of them. In this paper, the following subjects are studied theoretically and on the basis of past experimental results. 1) Slip failure strength of the wall panel 2) Failure modes and ultimate strength of the surrounding frame 3) Confining effect of the surrounding frame on the wall panel When the surrounding frames have large confining effect, the ultimate shear capacity of shear walls is governed only by the slip failure strength of wall panels, and is not affected by the strength of the surrounding frames. In this paper, rational expressions for estimating the ultimate shear capacity of shear walls are proposed to design shear walls, as follows. q_wu=<Q_wu>/<F_clt>=b_c(1+2β_sp_w)ζ_t…(2.1), (2.2) Q_<wu> : ultimate shear capacity of shear wall F_c : compressive strength of concrete l, t : horizontal length and thickness of wall panel β_s=σ_<wy>/F_c, σ_<wy> : yield stress of wall reinforcement p_w : wall reinforcement ratio ζ_t : effect of axial load on the shear strength of wall panel, Eq. (2. 3) b_c=b_<cu>…(16.1) b_<cu>=0.444 - 0.076 (F_c/200)…(5) : coefficient for slip failure strength of wall panel, F_c : kgf/cm^2 In the case of "small confining effect" of the surrounding frame η_c : η_<co> + β_fk_f &lt;…(16.1), (19), (22) In the case of large confining effect of the surrounding frame : η_c = 1 η_<co> : effect of wall panel K_f : confining coefficient defined by the flexural and shear strength of frame members to the strength of wall panel β_f : coefficient decided by the past experimental results, Furthermore, β_f is related theoretically with failure modes of surrounding frames.