混凝土结构的静力和动力损伤非线性分析

Nonlinear analysis of concrete structures under static and dynamic loadings

首先简要介绍混凝土统一弹塑性损伤本构模型,该模型能够直接在材料本构层次考虑阻尼的影响, 同时又可以较好地描述混凝土材料刚度退化、强度软化、有侧限时受压强度提高、双轴拉压软化效应、卸载 后存在的不可恢复变形、单边效应等静力非线性行为以及应变率效应等动力非线性特性．利用上述模型, 分别对混凝土材料试验、钢筋混凝土剪力墙以及Koyna混凝土重力坝进行了静力和动力非线性分析．分析 结果表明,建议模型可以应用于大型(钢筋)混凝土结构非线性分析,除了能够提供荷载作用下的常规结构 反应外,还可以实时地提供结构损伤分布及其演化信息．

Concrete demonstrates typical nonlinear performances under staitc loadings, e.g. , the stiffness degrading, the post - peak strength softening, the strength enhancement under compressive confinement , the tension - compression softening, the irreversible deformations upon unloading and the unilateral effect, and those under dynamic loadings, such as the damping and the strain rate effect, which should be well described by the constitutive relation used in the nonlinear analysis of concrete structures. A unified framework of the elastoplastic damage model for concrete is first briefly introduced, which is capable of describing all the above nonlinear behavior of concrete and directly takes the damping into consideration on the material level. The proposed unified model is then applied to the nonlinear analysis of concrete specimens and structures under static and dynamic loading conditions, and the predicted results demonstrate its capability and superiority in discribing the nonlinear responses of (RC) concrete structures.