Effect of thermal loading on integral abutment-deck structures

The most influential lateral loading on integral bridges is due to daily and seasonal thermal expansions and contractions of the superstructure which forms the main focus of this research. As the temperature of an integral bridge changes, the length of the bridge increases and decreases, pushing the abutments against the backfill and pulling it away, causing lateral deflections at the abutment and top of the piles that support the bridge. As a result, complex interactions take place among the abutment, the backfill, the foundation soil, and the piles supporting integral bridges. In this research, simplified frame models were analyzed using SPACEGASS to investigate these complex interactions and help reinforce the findings in the literature review. The backfill in all simulations was modeled as a cohesionless granular soil. The soil was modeled as spring supports with spring's axial stiffness based on the modulus of subgrade reaction of the soil. Four scenarios were created and analysed in SPACEGASS; deck length (50 m/100 m), deck material (steel/concrete), soil stiffness and temperature variation.