Behavior of Nonlinearly Restrained Slender Bridge Piers

The load-carrying capacity of slender reinforced concrete piers depends on the horizontal retaining forces exerted by the bridge deck. The magnitude of these forces is a function of the behavior of the restraints connecting the deck to the piers and to the abutments, as well as of their evolution in the presence of increasing loads. A numerical method, that was developed to perform a geometrically and mechanically nonlinear analysis of the piers, is described in this paper. This method also takes into account the evolution up to failure of the behavior of the restraints. By means of computations on a large number of different restraint conditions on a real bridge, it is shown to what extent the restrain effects exerted by the bridge deck may affect the safety factor γf on the action side of the piers. Elastic-rigid restraints and sliding-rigid restraints are considered; both of them are able to stop after a predetermined displacement value, becoming infinitely rigid beyond this value.