Shear and Torsion Response of Reinforced Concrete Structures

钢筋混凝土结构的剪切和扭转响应

• 批准号: RGPIN-2017-06613
• 负责人: Collins, Michael
• 金额: $ 3.72万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=690274
• 关键词: Shear; Torsion; Response; Reinforced; Concrete

The objectives of this long-term research program are to improve understanding of the mechanisms by which cracked reinforced concrete transmits shear stresses and use this understanding to develop analytical tools which structural engineers can use to design new structures and evaluate the safety of existing concrete structures. Shear failures can cause concrete structures to collapse without warning and, hence, are of critical concern for public safety. It is now known that older North American shear and torsion design procedures used for a significant portion of existing concrete infrastructure can result in buildings, bridges, silos and nuclear power plants which may have inadequate margins of safety against such failures. Such structures are particularly prone to collapse during earthquakes.***One of the major objectives of the next five years is to improve the understanding of combined torsion and shear and develop the tools to decide which structures must be repaired. This will be done by conducting experiments on intensely instrumented elements of reinforced concrete subjected to loading that simulate the actual conditions encountered in practice. Recently developed techniques will be improved to enable the formation, propagation and sliding of critical cracks to be recorded so that the characteristics of crack patterns of impending shear collapse can be accurately defined. The influence of reversed cyclic loading on crack propagation and bond deterioration for members containing reinforcement details representative of those in older existing structures will be studied and the effects of restraint of shrinkage and thermal movement will be simulated. The experimental studies will be supplemented with extensive nonlinear 2D and 3D finite element analysis. Finally, simple analytical models suitable for use by practicing engineers to evaluate existing structures for shear safety will be developed. The research will be conducted by graduate students who will develop a deep understanding of the shear behaviour of reinforced concrete structures under extreme loads. After such research they will be equipped to contribute to the safety assessment of Canada's critical concrete infrastructure.

这个长期研究计划的目标是增进对开裂钢筋混凝土传递剪应力的机制的理解，并利用这种理解来开发分析工具，结构工程师可以使用这些工具来设计新结构并评估现有混凝土结构的安全性。剪切破坏可能导致混凝土结构在没有警告的情况下倒塌，因此对公共安全至关重要。现在我们知道，现有混凝土基础设施的很大一部分所使用的较旧的北美剪切和扭转设计程序可能会导致建筑物、桥梁、筒仓和核电站对于此类故障的安全裕度可能不足。此类结构在地震期间特别容易倒塌。***未来五年的主要目标之一是提高对扭剪组合的理解，并开发工具来决定哪些结构必须修复。这将通过对受载荷的钢筋混凝土的密集仪器元件进行实验来完成，模拟实践中遇到的实际情况。最近开发的技术将得到改进，以记录关键裂纹的形成、扩展和滑动，从而准确定义即将发生剪切塌陷的裂纹模式的特征。将研究反向循环荷载对包含旧现有结构中具有代表性的钢筋细节的构件的裂纹扩展和粘结恶化的影响，并模拟收缩和热运动的抑制效果。实验研究将得到广泛的非线性 2D 和 3D 有限元分析的补充。最后，将开发适合执业工程师用来评估现有结构的剪切安全性的简单分析模型。该研究将由研究生进行，他们将对极端荷载下钢筋混凝土结构的剪切行为有深入的了解。经过此类研究，他们将有能力为加拿大关键混凝土基础设施的安全评估做出贡献。