Design of bridges utilizing a novel earthquake resistant abutment with high capacity wing walls

Abutments are not considered to participate strongly in the earthquake resisting system (ERS) of Eurocode-based designed bridges. However, previous studies showed that seat-type abutments can reduce effectively the seismic actions of bridges, especially when the openings at the expansion joints accommodate only the serviceability movements of the deck. Alongside, a wide field of study is open to new abutment configurations and innovation, as no unified procedure is available for their design and construction. In this framework, a new earthquake resistant abutment with high capacity wing walls is proposed and analytically investigated. The proposed abutment decouples the in-service response of the bridge from the backfill soil by small clearances at the expansion joints, which separate the deck from the abutment. During an earthquake the bridge movements are restrained by the high capacity wing walls and the backfill soil. The seismic performance of the new earthquake resistant abutment is evaluated by utilizing a benchmark bridge, whose design was based on Eurocodes, which has a relatively expensive isolation system with lead rubber bearings and dampers. Two alternative design schemes that utilized the seismic restraining effect of the proposed earthquake resistant abutment were re-designed and compared to the benchmark on the basis of seismic resistance and cost-effectiveness. The comparative results showed that the seismic participation of the proposed abutment with the backfill soil reduces effectively the seismic demand of the re-designed bridge schemes. Accordingly, the initial and the final bridge costs are effectively decreased, showing that the proposed unconventional design is a reliable scheme for future designs of bridges in earthquake-prone areas.