Seismic Performance of Bridge Pier Circular Columns with Encased Steel Section

The use of encased steel profiles in concrete columns is a well-established technique in the field of building construction. However, the utilization of this technology in bridge engineering, especially in areas prone to seismic risk, has not been thoroughly investigated. Since the steel profile inside the concrete has more cover than the outer bars, it will be preserved in a harsh environment, which leads to an increase in the durability of the system. In addition, utilizing the core steel element in retrofitting processes provides the required resistance, allowing for structural work to be conducted without the need for rerouting traffic, which ensures the continuous flow of traffic and enhances public comfort. As a first step in the research, the potential use of the proposed system in low and moderate seismic regions like Montréal is studied. The effective stiffness of the steel–concrete composite circular columns and its subsequent effect on the seismic demand imposed on them are investigated and compared to that of reinforced concrete (RC) columns. Also, using a real-dimension model of a bridge made with CSI-Bridge software, a comparison is made between the performance of RC piers and the equivalent alternative composite system in terms of structural response, columns factored, nominal, and expected resistance in low and moderate seismic zones. The Canadian code CSA S6-19 requirement design criteria are used to design both RC and composite columns by the force base design (FBD) method. The results show that the composite system can act similarly to RC piers concerning the parameters under consideration.