有限要素法による鉄筋コンクリートの非線形解析 : 第 1 報 : 二軸応力下のコンクリートの応力-歪関係

抄録

It is the purpcse of this investigation to discuss the applicability of the previous analytical models which represent the biaxial stress-strain relations for concrete. For that purpose, the five analytical models are compared with the experimental data of Kupfer, Hilsdorf and Rusch (8) and Nelissen (9). These five analytical models are as follows. 1) The isotropic material model of Kupfer and Gerstle derived by curve fitting their own experimental data. (10) 2) The orthotropic model of Liu, Nilson and Slate, in which the Poisson's effect is separated from the the microcrack-confinement effect. (11-13) 3) The orthotropic material model of Darwin and Pecknold based on the concept of the equivalent uniaxial strain. (14) 4) The isotropic material model of Romstad, Taylor and Herrmann based on the assumption that the progressive damage concepts described for uniaxial compression are applicable to the biaxial response. (15) 5) The model based on the theory of plasticity for the compressible materials. (16-19) As the results of the comparison, the model based on the theory of plasticity for the compressible materials, which has been used by many investigators in Japan, cannot represent the nonlinear behavior of concrete adequately. At high stresses this model is unreasonably hard in the both principal directions. This tendency is more remarkable, as α, the ratio of σ_1 to σ_2, becomes more positive for biaxial compression, as shown in Fig. 7-b, 13-b and 14-b. And the orthtropic material model of Darwin and Pecknold gives the best result in the both principal directions, as shown in Fig. 7-b, 13-b, 14-b and 10.