Fatigue Resistance of Quarter-Scale Bridge Stringers in Flexure and Shear.

摘要

Approximately 1,800 miles of short-span and multiple short-span wood bridges and trestles are located on Class I railroads in the United States. Practice varies in different areas, but timber stringer bridges are used on both main and branch lines. Stringers were formerly replaced at fairly frequent intervals because of decay in timbers. The present universal practice of treating these timbers with preservatives has extended the life of bridge stringers. The lengthened service life of the timbers, however, has raised questions about the fatigue resistance of the stringers, since bridges are subjected to numerous repetitions of loading.