Abstract
Fatigue strength of the joint between diaphragms and longitudinal ribs on lower flange in box girder of suspension bridge was investigated by means of fatigue tests and stress analyses. Fatigue tests were carried out on large scale specimens which were models of transverse section of box girder and had various size of cope holes at the crossing joints. It was found that smaller cope hole was appropriate for reducing the local stress and increasing fatigue strength. However, when no cope hole existed, high stress concentration occurred at the flange plate inside of through rib and fatigue strength became low.
