Report No.: CCEER-98-4

Title: Full-Scale Field Capacity Tests of a Railway Bridge

Authors: Emmanuel "Manos" Maragakis, Bruce M. Douglas, and Qingbin Chen

Date: June 1998

Sponsoring Agency:

California Department of Transportation

Performing Organization:
Department of Civil Engineering/258
University of Nevada, Reno
Reno, NV 89557


Full scale ultimate load tests of the bearings of the Strawberry Park Bridge were conducted in March 1995. This was a two span 148' long ballasted railway bridge, typical of many railway bridges around the country. The bridge was located in Los Angeles and it was scheduled for removal in spring 1995. This fact allowed for the performance of failure push tests of the bridge with the pushing loads applied at the abutments of the bridge. The main objective of this experiment was to begin to identify the extent to which the unique railway bridge components, consisting of the rails, ties, ballast and ballast pan, contribute to the lateral load and displacement capacity during a seismic event. At one end, the rails, the ballast and the ballast pan were completely removed or severed. The other end was left in its "as built" condition. The bridge was then pushed laterally to failure at both ends. To minimize the load transfer to the pier and to allow a direct comparison between the failure loads at the abutments, the rail, the ballast and the ballast pan were removed or severed at the pier. The assessment of the influence of the unique railway elements on the ultimate capacity of the bridge was accomplished by examining the results at the "free" end of the bridge at the west abutment and comparing them to those obtained at the "as built" east abutment. It was found that the railway elements increased significantly the ultimate lateral system capacity of the bridge (Abstract by authors).