Temperature-driven fatigue life of reinforced concrete integral bridge pile considering nonlinear soil-structure interaction

In this study, a five-span fully integral reinforced concrete (RC) bridge has been investigated for fatigue life assessment of its RC piles considering the effects of environmental temperature variation and nonlinear soil characteristics. The effect of daily temperature variation on the abutment wall and pile foundation has been estimated. Multilayers of soil along the abutment pile depth have been considered in the formulations. The soil has been represented as 3D nonlinear springs. A new fatigue model has been used for crack initiation and propagation in the RC piles. In this model, a crack has been assumed to progress successively in three stages from the tension side of the pile. Finite element (FE)-based modeling and analyses have been carried out to determine the longitudinal displacements and bending moment in piles, abutments, and piers. Furthermore, taking the bending moment as input crack mouth opening distance, crack propagation and fatigue life of pile have been assessed using the FE method-based software. It is seen that the abutment piles suffer fatigue damage earlier as compared to the pier-piles as a result of thermal and vehicular loads effects. Also, thermal fluctuation has shown little or no fluctuations in the longitudinal displacements of abutment and piles in the multispan fully integral bridge (FIB). It is expected that the proposed method will be helpful for the bridge engineers in designing the pile foundation passing through multiple soil layers against fatigue damage of a FIB in particular subjected to thermal and vehicular loading.