Residence Time of Cl⁻ on Inside-ward Web of Girder of the Bridge

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.