Advancing the Seismic Design Practices of Concrete Bridge Piers Reinforced with High Strength Steel Rebars

在加拿大和世界范围内，混凝土建筑中对高强度钢（HSS）钢筋的需求不断增加。这种需求是由需要建立更大，更复杂的结构，以满足人口和社会的需求。建筑拥挤是寻求HSS的另一个动机。在混凝土结构中引入HSS有可能减少钢材的总体积，这可以转化为与制造、装配和运输相关的能源消耗的减少，同时沿着成本降低。然而，由于加拿大设计规范对在非抗震和抗震应用中使用HSS钢筋施加的限制，我们无法充分利用HSS钢筋的潜力。本研究旨在通过执行一项全面的研究计划来缓解设计规范委员会对HSS在抗震应用中的使用的担忧，该研究计划对HSS在桥梁柱中的性能进行评估和记录。为了实现研究目标，将采用实验和数值计算相结合的技术。第一阶段将涉及评估加拿大市场上可用的HSS钢筋的机械性能。在材料层面，重点将放在HSS的低周疲劳性能和开发适当的疲劳寿命预测模型上。在构件水平，将对用HSS加固的混凝土桥梁柱进行一系列大型拟静力循环试验。所产生的实验数据将用于验证基于纤维单元的数值模型。数值模型将用于预测应变和漂移为基础的极限状态与HSS钢筋混凝土桥梁柱的列将有广泛的几何和材料性能。从数值表达式中生成的数据将用于开发设计表达式，以促进HSS加固桥梁柱的性能设计。研究团队将与设计规范委员会密切合作，制定适当的框架，以便将拟议的设计建议纳入设计规范中。

There is an increased demand for high-strength steel (HSS) reinforcing bars in concrete construction in Canada and worldwide. This demand is fueled by the need to build larger and more complex structures to address population and societal demands. Congestion in construction is another motivation for seeking HSS. Introducing HSS in concrete construction has the potential to reduce the overall volume of steel, which could translate to reductions in energy consumption related to manufacturing, fabrication, and shipping along with cost reduction. However, we are unable to make use of the full potential of HSS rebars due to the restrictions imposed by Canadian design codes on the use of HSS rebars in both non-seismic and seismic applications. This research aims to alleviate design code committees' concerns regarding the use of HSS in seismic applications by executing a comprehensive research program where the performance of HSS in bridge columns is assessed and documented. To achieve the research objective, a combination of experimental and numerical techniques will be employed. The first stage will involve evaluating the mechanical properties of HSS rebars available in the Canadian market. At the material level, a large emphasis will be placed on the low-cycle fatigue performance of HSS and the development of appropriate fatigue life predictive models. At the member level, a series of large-scale quasi-static cyclic tests will be performed on concrete bridge columns reinforced with HSS. The generated experimental data will be employed to validate a fiber element-based numerical model. The numerical model will be used to predict strain- and drift-based limit states for concrete bridge columns reinforced with HSS where the columns will have a wide range of geometrical and material properties. The data generated from the numerical expressions will be used to develop design expressions facilitating the performance-based design of bridge columns reinforced with HSS. The research team will work closely with the design code committee to formulate the appropriate framework with which the proposed design recommendations can be incorporated in the design codes.