Vibrations of partly supported concrete railway sleeper

Abstract: Analytical and finite element solutions to the problem of a vibrating beam on an elastic foundation are presented. An application example is a concrete railway sleeper embedded in an elastic medium (the ballast). The sleeper is also elastically connected to the rails. Eigenfrequencies are calculated and vibration modes are discussed. The beam (sleeper) is divided into sections where each section may or may not be supported by the elastic foundation. The elastic connections to the rails are situated at the two joinings of the three sleeper sections. Some conclusions are that Euler-Bernoulli beam theory can be used to calculate two, or maximum three, eigenfrequencies of the sleeper. The foundation stiffness influences the lowest bending-mode eigenfrequency the most; higher eigenfrequencies are practically unaffected by the foundation stiffness. The influence of railpad (and rail) stiffness on the sleeper eigenfrequencies is negligible.