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

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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.