Proposed Seismic Design Methodology for Steel Pier-Pile Integrated Structure Considering Dynamic Soil-Pile Interaction and Ductility Performance of Elongated Members

This paper discusses the seismic design policy and the design results for a novel pier-pile integrated rigid frame bridge, herein, denoted as the Pier-Pile Integrated Structure. The novelty of the structure lies in its foundation as the footing is eliminated leading to reduced substructure size, in turn, leading to reduced cost, construction time, and the need for topographic modification. The traditional design methodology for foundations with the assumption of fixed support or a rigid member at the footing does not hold for these structures. Hence, a novel seismic design methodology is proposed that considers the ambiguity in the failure mechanism and the ductility performance of ERW SKK 490 steel. Additionally, the seismic response and performance objective are set according to related past studies to form a comprehensive seismic design methodology for practical design. The proposed methodology is then applied for design of a road bridge and a comparison to the conventional design philosophy is presented.