Finite Element analysis of Transverse Shear Failures in Reinforced Concrete Plates and Shells

厚板壳抗冲切性能的研究 将由钢筋混凝土制成。 为了执行 通过研究，提出了一种新的裂缝混凝土本构关系， 它允许在许多非正交的 方向，并正确地模拟界面剪切传递 混凝土的特性，特别是摩擦力和粘性 结合断裂能的裂纹行为 有裂缝。 现有的测试结果将被分析并用于 量化和细化改进的材料模型。 分析研究将使用二维有限 单元、三维实体有限元和一种新的 剪切型分层板壳单元新方法 变形比通常的分层更准确地表示 理论 此外，剪切破坏的可能性和 包括箍筋。 将对一系列板壳进行分析以验证其有效性 的方法和新材料模型的适当性。 要分析的最后一系列板和壳将是 国家调查局最近进行的一系列测试 根据单独的合同。 这些测试模拟 由于集中冰力作用于近海， 结构. 这些测试已经得到了合理的分析 成功地使用改进的材料模型。 最后，开发的程序将用于执行一系列 参数研究，以开发简化的设计方程。 研究的参数包括抗剪配筋率、壳 曲率和边界条件。

The study of the punching shear resistance of thick plates and shells made of reinforced concrete will be conducted. In order to perform the study, a new constitutive law for cracked concrete will be developed which allows cracks to form in many non-orthogonal directions and which correctly models the interface shear transfer characteristics of concrete, in particular the friction and dilatancy behavior of cracks in combination with the fracture energy associated with the crack. Existing test results will be analyzed and used to quantify and refine the improved material models. The analytical study will be performed using two dimensional finite elements, solid three dimensional finite elements and a new innovative approach to layered plate and shell elements whereby shear deformation is more accurately represented than in usual layered theory. Further, both the possibility of shear failure and the inclusion of stirrups are considered. A series of plates and shells will be analyzed to verify the validity of the approach and the appropriateness of the new material models. The final series of plates and shells to be analyzed will be the series of tests that were recently performed at the National Bureau of Standards under a separate contract. These tests simulate punching shear due to concentrated ice forces acting on offshore structures. These tests have already been analyzed reasonably successfully using improved material models. Finally, the program developed will be used to perform a series of parameter studies in order to develop simplified design equations. Parameters to be studied include shear reinforcement ratios, shell curvature, and boundary conditions.