Service Load and Fatigue Tests on Truss Bridges

With the construction of the Saylorville Dam and Reservoir on the Des Moines River in Iowa, six highway bridges were scheduled for removal. Two of these were incorporated into a comprehensive test program to study the behavior of old pin-connected high-truss single-lane bridges. The test program consisted of ultimate load tests, service load tests, and a supplementary static and fatigue testing program of selected members. The results reported in this paper cover the service load tests on the two bridges as well as the supplementary tests, both static and fatigue, of eyebar members taken from the two bridges at the time of removal. The field test results of the service loading are compared with theoretical results of the truss analysis.