Abstract
Cl− is known to influence corrosion rate of girders of steel bridges. In general, precipitation rate of air-born salt is used to discuss the stability of steel bridges in a corrosion environment. However, residence time of Cl− on girder is considered to directly affect the corrosion of girders of steel bridges, while precipitation rate of Cl− is one of the factors in residence time of Cl−. In addition to precipitation rate of Cl−, in this study, the Cl− abundance on web and the quantity of Cl− removed from web due to rinsing with dewdrop on the girders were analyzed during February to May 2012, in order to examine the residence time of Cl− on the girder of the bridge. As a result, the residence time of Cl− on inside-ward web of the girder is calculated to be several tenths to several hundreds days. Though there is a possibility that fluctuation of Cl− precipitation rate during a month causes error of the residence time, the continuing analysis up to one year for the bridge probably make it possible to yields more reliable residence time of Cl− on the girder.
