REMAINING STRENGTH EVALUATION OF PLATE GIRDERS WITH CORROSION NEAR SUPPORTS

Abstract

In Japan, a lot of steel railway bridges were constructed during the period of rapid economic growth in the 1960s. Now, since over 50 years have passed, the aging of these structures has become conspicuous and a major social problem. In particular, for steel plate girders with open deck system, deterioration and damage due to corrosion is becoming obvious. Moreover, the remaining strength evaluation method of corroded structures is not always sufficient. Therefore the purpose of this study is to propose an analytically-based evaluation method for the maintenance of steel railway bridges. The following are noted: 1) Regarding the shear strength of plate girders with corrosion near supports, the remaining strength depends on the corroded surface condition of each component such as a web or a vertical stiffener. And, according to the form and degree of corrosion, the fracture mode also changes from the buckling of web to the buckling of cross-shape column consisting of the web and vertical stiffener. The result shows that the corroded web has more effect on the shear strength than the vertical stiffener. 2) Regarding the peeling between the web and bottom flange due to corrosion near supports, the remaining strength is deteriorated more rapidly than above case 1, when the peeling range lengthens more than the sole plate area.