Moving Loads on a Viscoelastic Foundation with Special Reference to Railway Transition Zones

Abstract

At railway transition zones between soft ground and stiffer structures, dynamic actions between the railcar, track, and subgrade induce differential settlements that may cause vibration and noise, compromise ride quality, and incur relatively high maintenance costs. Using a semianalytical spectral Galerkin method, this study attempted to examine stiffness transitions for point loads traveling on a pinned beam resting on a Winkler spring foundation with damping. Generally, a different deflection behavior occurs when moving from stiff-to-soft or soft-to-stiff regions. Multiple loads induce additional oscillatory behavior that is not typical of single loads. This study showed that a minimum transition length of 8–1 times the system’s characteristic length appears necessary to avoid stiffness transition deflection spikes. A real rail transition zone taken from a case study in Portugal was also analyzed.