INVESTIGATION OF THE BRITTLE FRACTURE AT THE CORNER OF P75 RIGID-FRAME PIER IN KOBE HARBOR HIGHWAY DURING THE HYOGOKEN-NANBU EARTHQUAKE

Abstract

P75 steel rigid-frame pier in Kobe Harbor Highway was done damages proceeding large cracks to the corner under the Hyogoken-Nanbu Earthquake. This paper presents the consequences of observation of the fracture appearance, examination of the material property and calculation of the strain occurred under this earthquake. According to observation of the fracture appearance, the brittle appearance is recognized on the cracks proceeding from the toe of fillet weld. According to examination of the material property, it is found the toughness of the base metal and the deposited metal around the initiation of crack is deteriorated by the prestrain exceeding the yield strain. According to calculation of the strain using finite element analysis, it is presumed that the strain and the strain velocity on the corner are very high. From these results, it is concluded that the brittle fracture is occurred by the deterioration of the toughness of the base metal and the deposited metal, and the high strain velocity.