Determination of the optimal span length to minimize resonance effects in bridges on high-speed lines

This paper revisits the creation and cancellation of the dynamic resonance phenomenon that occurs in bridge structures on high-speed lines when crossed by wheel loads. The resonance and its cancellation are mathematically formulated for a Bernoulli-type beam with general boundary conditions and subjected to loads moving at a regular spacing. The resonance of the bridge caused by the travelling loads occurs, regardless of the mode shape, when the natural frequency of the structure coincides with the loading frequency produced by the loads moving at a constant speed. In this study, the dependency of the cancellation phenomenon on the mode shape is determined based on the boundary conditions of the structure. In addition, the optimal span length that suppresses the response at resonance is proposed using the cancellation phenomenon for a simple beam with pinned-pinned, clamped-clamped and clamped-pinned boundary conditions; and a simply supported continuous beam.