This paper utilises non-linear finite-element analysis with three-dimensional (3D) solid elements to gain insight into the role of shear reinforcement in increasing punching shear resistance at internal columns of flat slabs. The solid element analysis correctly captures the experimentally observed gradual decrease in concrete contribution to shear resistance with increasing slab rotation and the failure mode but is very computationally demanding. As an alternative, the paper presents a novel approach, in which 3D joint elements are combined with non-linear shell elements. Punching failure is modelled with joint elements positioned around a control perimeter located at 0.5d from the column face (where d is the slab effective depth). The joint elements connect the nodes of shell elements located to either side of the punching control perimeter. The punching resistance of the joints is related to the slab rotation using the failure criterion of the critical shear crack theory. The joint-shell punching model (JSPM) considers punching failure both within the shear-reinforced region and due to crushing of concrete struts near the support region. The JSPM is shown to accurately predict punching resistance while requiring significantly less computation time than 3D solid element modelling.

中文翻译：

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抗剪钢筋混凝土平板冲剪破坏数值模拟

本文利用三维 (3D) 实体单元的非线性有限元分析来深入了解抗剪钢筋在增加平板内柱冲剪抗力方面的作用。固体元素分析正确地捕获了实验观察到的混凝土对抗剪强度的贡献随着板坯旋转和破坏模式的增加而逐渐降低，但计算要求很高。作为替代方案，本文提出了一种新方法，将 3D 关节单元与非线性壳单元相结合。冲孔失效通过位于距离柱面 0.5 d的控制周长周围的节点单元进行建模（其中d是板坯有效深度）。节点单元连接位于冲压控制周边任一侧的壳单元节点。利用临界剪切裂纹理论的破坏准则，接头的抗冲性与板坯旋转有关。节点壳冲孔模型 (JSPM) 考虑了在抗剪加固区域内以及由于支撑区域附近的混凝土支柱压碎而导致的冲孔失效。JSPM 被证明可以准确预测冲压阻力，同时比 3D 实体元素建模所需的计算时间要少得多。