Abstract:
In this study a dynamic analysis of a 77-year-old single-span steel truss railway bridge was
carried out. The study was approached by three different methods – field measurement,
modal analysis using a three-dimensional finite element model of the bridge, and a simple
generalised single degree of freedom (SDOF) analysis. Field measurement was conducted using
accelerometers and displacement transducers, which were mounted on special sections fixed
to an adjacent bridge. The finite element models of the bridge were prepared using beam
and shell elements. The dynamic responses studied include the displacement, acceleration
and natural frequency of the bridge. The results showed that the generalised SDOF model,
with simple addition of the effects of each axle, provided reasonably accurate displacements
compared to the measured values. The generalised SDOF model, finite element model with
beam elements and finite element model with shell elements also gave reasonably accurate
estimates for the natural frequency of the bridge.
