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，混凝土施工中对高强度钢（HSS）钢筋的需求不断增加。这种需求是由于需要建造更大、更复杂的结构来满足人口和社会需求。建设中的拥堵是寻求HSS的另一个动机。在混凝土结构中引入高速钢有可能减少钢材的总量，这可能转化为与制造、制造和运输相关的能源消耗的减少，同时降低成本。然而，由于加拿大设计规范对在非地震和地震应用中使用HSS钢筋的限制，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减轻设计规范委员会对在地震应用中使用HSS的担忧，该计划对桥梁柱中HSS的性能进行了评估和记录。为了达到研究目的，将采用实验和数值技术相结合的方法。第一阶段将包括评估加拿大市场上可用的高速钢钢筋的机械性能。在材料层面，重点将放在高速钢的低周疲劳性能和开发适当的疲劳寿命预测模型上。在构件水平上，将对HSS加固混凝土桥柱进行一系列大型拟静力循环试验。生成的实验数据将用于验证基于纤维单元的数值模型。该数值模型将用于预测HSS加固混凝土桥柱的应变和基于漂移的极限状态，其中柱将具有广泛的几何和材料特性。由数值表达式生成的数据将用于开发设计表达式，以促进HSS加固桥梁柱的基于性能的设计。研究小组会与设计守则委员会紧密合作，制订适当的架构，把建议的设计建议纳入设计守则。

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.