Development of an Embedded Crack Method for the Shear Behavior of Reinforced Concrete Structures

研究的重点是开发一种用于评估混凝土和砌体结构的可用性和安全性的嵌入式裂缝分析方法。钢筋混凝土/砌体结构受延性材料和脆性材料的共同作用，其性能十分复杂。随着钢筋的加入，不同的极限状态和破坏模式，从延性到脆性，可以在混凝土/砌体结构中演变，这取决于加载条件和钢筋的数量。掌握这些机制的能力对于评价现有的民用基础设施系统以及设计新结构至关重要。现有的使用离散或涂抹裂纹建模方法的分析方法存在许多缺点。涂抹裂缝法不能反映钢筋混凝土深梁和剪力墙的脆性剪切行为，而离散裂缝法不适合模拟扩散裂缝。因此，第三种方法基于一种有效的方法，它不需要重网格，这在离散裂纹分析中经常需要，并且它能够通过在单元域中引入位移不连续来消除涂抹裂纹方法的主要缺陷。这是一个新的概念，在变分原理的基础上具有良好的理论基础。

The focus of the research is to develop an embedded crack analytical method for assessing the serviceability and safety of concrete and masonry structures. The behavior of reinforced concrete/masonry structures is complicated due to the interaction of ductile and brittle materials. With the addition of steel reinforcement, different limit states and failure modes, ranging from ductile to brittle, can evolve in concrete/masonry structures, depending on the loading conditions as well as the quantity of reinforcement. The ability to capture these mechanisms is of primary importance for the evaluation of existing civil infrastructure systems as well as for the design of new structures. Existing analytical methods using the discrete or smeared crack modeling approach suffer from a number of shortcomings. The smeared crack approach cannot capture the brittle shear behavior of reinforced concrete deep beams and shear walls, while the discrete crack approach is not suitable for modeling diffuse cracks. Hence, a third approach based on an efficient in that it does not require remeshing, which is often needed in the discrete crack analysis, and it is able to eradicate the major deficiencies of the smeared crack approach by introducing a displacement discontinuity within the element domain. The concept is new and has a sound theoretical basis founded on variational principles.