Numerical Modelling of Integral Abutment Bridges

Abstract

Integral Abutment Bridges (IABs) are well known for their lower construction and maintenance costs by eliminating expansion joints and bearings. The flexible piles supporting the end-span abutments offer the possibility of this expansion and contraction of the superstructure caused by the daily and seasonal changes in temperature. This thesis focuses on achieving integral bridge abutments' long-term performance by evaluating available backfill alternatives. Field results from a monitored integral abutment bridge in Fredericton, New Brunswick, were firstly used to simulate the non-linearity of backfill soils using two finite elements soil models (Mohr-Coulomb and Hardening Soil). The magnitude of lateral earth pressure from different backfill options was then estimated using the validated Hardening soil model. Further study reveals that this magnitude of lateral earth pressure increases with time, and it significantly depends on the stiffness property of the backfill material. As a result, it is suggested to be the first consideration in the design, as its maximum constant value is essential for the behaviour of integral bridge abutments.