抄録
A stability ratio was applied as an index expressing the P-Δ effects in inelastic earthquake response. The stability ratio includes the characteristics of the vibration system and the amount of energy exerted by an earthquake. The P-Δ effects in inelastic response cause the concentration of plastic strain energy into one side and the increase in ductility factor. The degree of the concentration and the increase can be estimated using the stability ratio as an index. The validity of this estimation method was verified by carrying out inelastic response analyses using SDOF models and MDOF models.
