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

对钢筋混凝土厚板壳的抗冲切性能进行了研究。为了进行这项研究，将发展一种新的裂缝混凝土本构关系，它允许在许多非正交方向上形成裂缝，并正确地模拟混凝土的界面剪切传递特性，特别是结合与裂缝相关的断裂能来模拟裂缝的摩擦和剪胀行为。现有的测试结果将被分析并用于量化和改进改进的材料模型。分析研究将使用二维有限元、实体三维有限元和层状板壳单元的一种新的创新方法，从而比通常的层状理论更准确地表示剪切变形。此外，还考虑了剪切破坏和箍筋夹杂的可能性。为了验证该方法的有效性和新材料模型的正确性，将对一系列板壳进行分析。要分析的最后一系列板壳将是最近在国家标准局根据另一份合同进行的一系列测试。这些试验模拟了作用在近海结构物上的集中冰力造成的冲切。这些试验已经使用改进的材料模型进行了合理而成功的分析。最后，开发的程序将被用来进行一系列参数研究，以建立简化的设计方程。需要研究的参数包括剪力配筋率、壳体曲率和边界条件。

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.