材料強度の変動と横方向変位を考慮したRC偏心軸圧縮部材(短柱)の耐力の逓減係数

抄録

It is desirable to design a structure and its members with a reasonable reliability. In the JSCE Code, it is defined that the designed strength of a RC-short column supported laterally at both ends under an axial load at a given eccentricity may be obtained by a simple method of neglecting an effect of lateral deformation of the member when the slenderness ratio is less than 35, using the reduction factor of 1/1.15. Here, a method to obtain a reduction factor for the strength of a double reinforced concrete member with a required reliability is proposed by using the probabilistic method of estimating the reliability, considering the variations in strength of both reinforcing bars and concrete, and taking account of an effect of lateral deformation. And, this study points out that in order to obtain a required reliability when applying this method to the combination of these two materials used in general, either the reduction factor of 1/1.15, prescribed in the JSCE Code, should be reduced appreciably, or the upper limit of the slenderness ratio, set at 35, of the member should be lowered by a large margin when employing the reduction factor 1/1.15 in the whole range of eccentricity.