Determination of Allowable Differential Settlement in Bridge Approach due to Vehicle Vibrations

Abstract

The differential settlement between the bridge abutment and the approach embankment produces the common “bump at the end of the bridge.” This paper conducts a theoretical study on the determination of the allowable differential settlement. The maximum transient vibration value of the acceleration is recommended as the vibration comfort index. A dynamic response analysis to Man-Vehicle-Road system is carried out by means of the Laplace transform in which the vehicle is modeled as a three-degree-of-freedom system, and the bridge approaches with and without approach-relative slopes are simplified as broken lines model and step model, respectively. Parametric studies are carried out to find out what kind of effects some parameters such as the driving direction and running speed may have on the allowable differential settlement. Finally, the method and computational procedures to determine the allowable differential settlement are presented.