Enhanced effective thickness for remaining strength estimation of corroded steel bridge members

Abstract

Infrastructure plays a major role in the economy of a country. Bridges are a major component of any infrastructure and the failure of a bridge will affect the economy of any country. Over the past decades there have been many damage examples of older steel bridge structures due to corrosion around the world. Exposure of a steel structure to the natural environment and inadequate maintenance will cause corrosion and leads to impairment of its operation. Efficient maintenance, repair and rehabilitation of existing bridges require the development of a methodology that allows for an accurate evaluation of load carrying capacity and prediction of remaining life. Therefore, careful evaluation of remaining load-carrying capacities of corroded steel bridge structures is of high importance in transportation and maintenance engineering. Even though there are some published methods to assess the strength reduction due to corrosion of bridges, all of them were developed by using specimens with about 30mm width. However during the preliminary investigation, it was found that many corrosion pits with more than 30mm diameters exist in actual severe corroded members. So, the influence of such corroded conditions could have been neglected and hence their actual remaining strengths might be different than those were obtained from those experimental studies. Therefore, this paper investigates the effect of actual corroded conditions on their remaining strength capacities and proposes a simple, efficient and accurate residual strength estimation method by using an enhanced effective thickness parameter with the correlation of maximum corroded depth, which can be used for the maintenance management of aged steel bridge infrastructures.