Evaluation of failure mechanism and size effect of confined concrete under axial compression using mesoscopic mechanical modeling

建立了考虑约束混凝土单轴受压破坏机理的刚体-弹簧模型-有限元耦合模型。在该模型中，采用细观本构模型，采用梁壳单元模拟钢筋侧向约束材料。通过将数值计算结果与经验公式或试验结果进行比较，验证了该模型能够合理地评价约束混凝土试件的受压响应。此外，还利用所提出的模型对试件尺寸的影响进行了参数研究，以探讨试件尺寸依赖的机理。

A coupled RBSM(Rigid-Body-Spring Model)-FEM model has been developed for evaluation of failure mechanism of confined concrete under uniaxial compression. In the proposed model, the RBSM is applied meso-scale constitutive models, and the steel reinforcing material for lateral confinement is modeled by a series of beam and shell elements. By comparing numerical results with the empirical formulas or the experimental results, it is confirmed that the proposed model can reasonably evaluate the compression response of confined concrete specimens. In addition, a parametric study of the influence of specimen size was conducted with the proposed model in order to discuss the mechanism of the size dependence.