A stress-strain model for uniaxial and confined concrete under compression

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• 作者：Ali Khajeh Samani ; Mario M. Attard ; ^{m.attard@unsw.edu.au}
• 关键词：High strength concrete ; Stress strain model ; Fracture energy ; Size effect ; Residual strength
• 刊名：Engineering Structures
• 出版年：2012
• 期刊代码：55_01410296
• 类别：et
• 出版时间：August, 2012
• 卷：41
• 期：Complete
• 页码：335-349
• 文件大小：5194 K

摘要

Analytical models for the full stress-strain relationship of confined and unconfined concrete in compression are required for the numerical simulation of the structural behavior of reinforced concrete structural elements. There are many analytical models presented in the literature, which are generally empirical and are based on tests either on plain concrete specimens or reinforced concrete columns. This paper reviews some widely used analytical models calibrated using triaxial test results on plain concrete and compares their predictions with available test data on uniaxial and triaxial compression on specimens with different specimen height, width or diameter and concrete strength. The model prediction鈥檚 for the peak stress and corresponding strain due to confinement are also compared. The residual stress level and the post-peak fracture energy under confinement are discussed. Estimates of the post-peak fracture energy per unit area are obtained from available experimental data showing that the post-peak fracture energy varies with confinement. The size effect on the softening behavior of uniaxial and triaxially loaded plain concrete specimens with different aspect ratios, heights and level of confinement, are also discussed. A new analytical model for unconfined and confined concrete is introduced which tries to address the limitations in previous models. The proposed model is capable of predicting the behavior of normal strength concrete, as well as high strength concrete and incorporates allowances for size effects dependent on specimen height and aspect ratio. Comparisons are made between the proposed new model, the models of others in the literature, and available compression triaxial and uniaxial test results.