Full-Scale Tests of a Railway Bridge

Full-scale resonance and ultimate load tests of the Strawberry Park Underpass were conducted in March 1995. This bridge was typical of many railway bridges around the country—a two-span, 45.2-m (148-ft) long ballasted through plate girder railway bridge. It was located in Los Angeles and scheduled for removal in spring 1995. This fact allowed failure tests to be performed with the pushing loads applied at the bridge abutments. The main objectives of this experiment were to measure the dynamic properties of the bridge with and without the rails and to begin to identify the extent to which the unique railway bridge components, consisting of the rails, ties, ballast, and ballast pan, help strengthen it during a seismic event. It was found that the removal of the rails alone resulted in a slightly softer system and that the railway elements increased the ultimate capacity of the bridge significantly.