Abstract
This report introduces the contents of an interative program briefly, which we have developed, for assessing the safety of steel structures against fatigue and for estimating those fatigue lives or remaining lives based on the Fatigue Design Recommen dations by Japanese Society of Steel Construction. Furthermore, following examinations are carried out by using this program. They are influences of span and static strength of steel used on fatigue life of railway and highway bridges, and an influence of plate thickness on fatigue strength of cruciform fillet welded joints with ground smooth weld toes.
