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Steel bridge on the roadway bridge,Japan.
Fatigue cracks were found in the sole plate welds at the girder support locations in 1990 after 22 years of service.
The outline of the bridge structure is as follows.
- Bridge length : 114.864m
- Span length : 35.0m+44.0m+35.0m
- Structure : Three spans continuous girder bridge.
- Structural steel : SM490A,SM490B,SS400
Fluctuating loads due to vehicles live load.
The location where the fatigue cracks were found were as follows.
- The fillet welding joint at the front side of the sole plate(Type-1).
- The fillet welding joint between the lower flange and the web(Type-2).
Type-1 crack penetrated the lower flange.The length of type-2 crack was 200mm.
Cause of fatigue cracks was as follows:
