Shear oscillations of bridge on sliding foundation during earthquake

Abstract

The article investigates the vibration of the railway bridge on the sliding foundation with dry friction under the action of real earthquake records at the intensity of 7, 8, 9, and over 9 on the MSK-64 scale. Dynamic dry friction problems are non-linear since each slip's start and end times are determined during the problem-solving process; they depend on many design parameters and external influences. The simplified model of vertical and shear deformation of the bridge is proposed as oscillating intermediate support with the mass of the span connected to the girth rail by a rubber bearing part. In this case, all elements in the structural model are connected to each other, taking into account eccentricities. The finite element method discretizes the coordinate variables and the Newmark time method with matrices built at each step. Structural vibrations are studied based on four real earthquake records. It is shown that using a sliding foundation can significantly reduce the shear forces in the bridge supports depending on the structure mass, the dry friction coefficient, and the nature of the seismic effect.