In this research a single span simply supported steel truss railway bridge is analyzed when subjected to train loads. The study was conducted by using three different methodologies namely modal analysis using three dimensional finite element models of a bridge based on As-built drawn from scratch; a time history analysis and field measurement on an existing bridge. The finite element models of the bridge were modeled using two methodologies; using beam and shell elements. A time history analysis involves developing an equation of motion for the forced and free vibration of the bridge when subjected to both a single- and successive train loads. The dynamic responses studied include the displacement, acceleration and natural frequency of the bridge which were compared for different train speeds, span length, and the mass of the bridge. Field measurement was conducted using accelerometers and displacement transducers which were mounted on a self-designed mounting section.
Dissertation (MEng)--University of Pretoria, 2015.