Fatigue life estimation parameter for short and medium span steel highway girder bridges

One of the main factors that affects the durability of a steel bridge is the fatigue phenomenon. Such a phenomenon is influenced by its structural and loading properties. Since steel bridges have been welded since the 1960s in Japan, the possibility of fatigue crack occurrence due to the primary stress of their main members increases each year the bridge is in service. This paper has been written in order to suggest a new parameter for arranging the fatigue life of the main girder of short and medium span I and box section girder steel highway bridges taking into consideration their structural and the loading properties, and to confirm the validity of the parameter. The results of this study can be conveniently used to find out under what condition a steel bridge is apt to be damaged by fatigue in the stage of design and maintenance.