LONG-TERM RESPONSE PREDICTION OF INTEGRAL ABUTMENT BRIDGE UNDER TIME-DEPENDENT EFFECT

Parametric study was conducted to assess the time-dependent effect of creep on longterm behaviour of prestressed concrete Integral Abutment Bridge (IAB). Varying backfill soil types (dense sand, loose sand, stiff clay, soft clay) were provided behind the bridge abutment and the interaction was modelled using linear springs. The effect of backfill soil type on the behaviour of the bridge was assessed through 75-year time-history numerical simulations using Finite Element Method. CEB-FIP 1990 creep model was used to analyse the linear viscoelastic behaviour of creep. The result of the long-term response prediction showed significant increase in bridge displacement due to creep. Displacement due to creep was found to be nearly five times displacement due to instantaneous loading and abutment bending moment increased by more than two times that of live and dead loads. There is marked difference in girder and abutment shears, abutment axial load and abutment moment as a result of variation of backfill soil. The Denser the backfill soil the lesser the magnitude of the reactions on the bridge abutment and girder indicating a favourable choice of compacted sandy soil behind integral bridge abutments.