An unconventional earthquake resistant abutment with transversely directed R/C walls

An analytical investigation is performed aiming at identifying the applicability and the seismic efficiency of an unconventional abutment, which restrains the seismic movements of the bridge deck. The abutment consists of the extension of the deck slab of the bridge onto transversely directed R/C walls with which the, so-called continuity slab, is monolithically connected. The restraining walls play the role of an additional horizontal and relatively flexible support of the deck of the bridge. The design of these restraining walls is based on two criteria referring to on one hand the accommodation of the in-service induced longitudinal movements of the deck and on the other hand on the earthquake loading of the walls. The walls are constructed in a concrete box-shaped substructure, which replaces the conventional wing-walls and retains the backfill material. The foundation of the abutment is checked and found to have adequate resistance against sliding and overturning. The proposed abutment was attempted to be implemented in a precast I-beam bridge. The study showed that the abutment can achieve a desirable control of the seismic movements of the deck and therefore reduces the seismic actions of the bearings, the piers and their foundation. The restraining effect of the abutment is also significant even in stiffer bridge resisting systems.