ABSTRACT
ABSTRACT: Bridge expansion joints have caused considerable maintenance problems to transportation agencies (Wolde et al. 1988a, b, Steiger 1993). Therefore, in many parts of NorthAmerica, the overall economy of jointless construction is made applicable to bridges where the abutments are cast integral with the deck and supported on a single row of steel Hpiles. In such integral bridges, the abutment-backfill system and the abutment piles (Dicleli 2005) may be influenced considerably by the thermal-induced displacements of the continuous bridge deck. The magnitude of the deck displacements is a function of the level of thermal variation, type of the superstructure material and the length of the bridge. As the length of integral bridges increases, thermal-induced displacements and the forces in the bridge components may increase as well. Since many transportation departments tend to push up the length limits of integral bridges to eliminate the maintenance problems concerned with the expansion joints, the abutments of such long bridges may be subjected to large internal forces in excess of their ultimate capacity. A reasonable estimation of the internal forces in the abutments is necessary in the design to ensure satisfactory performance of the integral bridge throughout its service life. This requires a careful study of the behavior of the abutment-backfill and soil-pile system under thermal variations. At present, design guidelines for determining the forces in integral bridge abutments considering the effect of thermal displacements on the shape and intensity of the backfill pressure and the effect of the pile-soil system do not exist inAASHTO (American Association State Highway Transportation Officials) Bridge Design Specifications (1998). Therefore, a rational method for the design of integral bridge abutments is required. Such a method may also be useful in determining the length limits of integral bridges based on the ultimate strength of the abutments.
