The corrosion survey of Tsukishima quay wall, the first lock gate and Uchihigashi breakwater have been carried out, and the following results were obtained.
(1)At Tsukishima quay wall, corrosion was concentrated only on the flat portion of convex steel piles directly under M.L.W.L., and holes were observed on the flat portions of 33percent of total convex steel piles. This tendency is corresponded to steet pile corrosion tendency (a)reported previously. On the other hand, at splash zone holes occured on the surface of those of 7percent of all steel sheet piles.
(2)Concentrated corrosion occured at protruding parts of members (i.e. edges of reinforcement)in the area within +0.7m to -0.7m at the first lock gate, and at extreme places corrosion rates exceeded 2mm/yr (one side). However, there was such tendency that when edges of reinforcement touched closely other steel members within +0.7m to -0.7m either by welding or rivetting, concentrated corrosion didn't almost occure at these portions.
(3)At Uchihigashi breakwater, cracks occured mainly at curved portions of steel sheet piles and steel piles ruptured finally in less than 17years.