We have been developing technologies of bridge inspections, reinforcements and repairs responding to the current needs of bridge maintenance. This paper outlines some of our technologies proved effective and efficient as follows:
(1) an under-deck inspection system using digitized image processing,
(2) a design proposal for steel girder reinforcements with outer cables, and the tests that prove its efficacy,
(3) close execution management for the reinforcement of a bridge by connecting simple girders, and
(4) the removal methods of high-tensile strength steel bolts imbedded in a concrete deck in order to replace them with new bolts.