Fatigue Performance of Modular Bridge Expansion Joints

Abstract

Several premature fatigue failures of modular bridge expansion joints have occurred in Europe and the United States. The principal causes of such failures have been poor detailing (for instance, choice of fillet welds instead of full-penetration welds) and the tendency to reduce production costs by adopting larger beam spans. A critical analysis of data from field measurements is discussed. This analysis is focused on (1) the magnitude of the forces acting on the considered component of the joint (center beam), (2) the dynamic amplification factor due to the impulsive axle loading, and (3) the dynamic properties of the joint such as damping, natural frequencies, etc. Comparisons with results obtained by other researchers are presented. A simplified method for the dynamic analysis of the joint is proposed and compared with results obtained from field measurements. Finally, results from laboratory fatigue testing are reported, together with a proposal for a “reasonable” fatigue design load, based on traffic considerations.