Ultimate Limit States of Bridge Abutments

This paper deals with the capacity of bridge abutments, which is an important element for the evaluation of the seismic performance of bridges with integral or semi-integral abutments and yet has received little attention in the scientific literature. We evaluate the capacity of the system formed by the abutment structure, the foundation soil, and the approach embankment under multiaxial loading conditions, based on a finite-element implementation of upper and lower bound theorems of plastic limit analysis. The ultimate conditions, including combined soil-structure failure mechanisms, are expressed by a capacity surface in a generalized force space that can be identified through a limited number of constitutive parameters. This ultimate limit state surface can be used for a direct verification of the abutment in force-based approaches, or it can be included in plasticity-based macroelements to provide a detailed description of the cyclic behavior of the soil-abutment system.