REMOVEMENT WORKS AND CORROSION INVESTIGATION OF COASTAL OBSERVATION PIER AT AJIGAURA BEACH

This paper describes the removement works and corrosion investigation of the 200m long coastal observation pier at Ajigaura beach, which was composed of steel truss framework supported by steel piles. The pier was constructed in 1973 and extended in 1976. The pier was used for observation of waves, currents and beach deformation in surf zone and exposed to severe sea state for more than 20 years. Removement works were operated from the provisional pier constructed in parallel to the observation pier. The steel piles were extracted after being cut beneath the ground level since they were judged to be undurable for the entire extraction due to the corrosion at the splash zone. Corrosion investigation also confirmed the effectiveness of various rustproof techniques.