Aging of social infrastructures such as steel bridges
necessitates the enhancement of maintenance technology.
This paper reports our new maintenance technologies
developed for that purpose.
1) Development of diagnosis technology with a portable
radiographic testing device applicable in the field and
its application to a bridge.
2) Development of an inspection method by electromagnetic
induction for welds and reinforcing-bar breaks.
3) Development of an inspection method by infrared thermograph
for internal defect detection.
4) Major repair and reinforcement of bridge parts of steel
piers and girders damaged by fatigue .
5) Aseismatic reinforcement of a bridge using steel arch
rib members.
6) Design proposal for girder reinforcement by outer
cables.
