Geo-structural Analysis of Integral Abutment Bridges
Abstract
Integral abutment bridges are jointless bridges where bridge decks and girders are integrated with abutments. The longitudinal displacements and rotations of the bridge are partially accommodated by the soil-pile system wherein the soil surrounding the piles generates active and reactive lateral forces when the piles deflect due to the movement of the superstructure. Since the soil stress-strain responses are inherently nonlinear, the pile deflection and the soil stiffness are interdependent. Consequently, evaluating soil-pile interactions requires a detailed geo-structural analysis. There are two common approaches used to idealize the soil-pile interactions for laterally loaded piles: the p-y and continuum mechanics approaches
This thesis first presents a critical review of the literature concerning integral abutment bridges and soil-pile interaction idealizations. Deformations of a specific free-ended single pile subjected to either a lateral force or moment at the pile head are idealized using the p-y and continuum mechanics approaches. Deformations and restraint force effects of a specific integral abutment subjected to thermally induced deformations or truck load is simulated with a 2-D finite element analysis with soil-pile interaction idealized using the two approaches. For both loading cases, influences of the two idealizations are compared and critically evaluated. A parametric study is conducted to investigate how the soil-pile interactions affect the response of bridges with various geometries, stiffnesses, and soil parameters. Further, this research presents a simplified model of an integral abutment and mechanics-based equations to quantify the deformations and restraint-induced load effects at the pile head and the end of the superstructure.