EXPERIENCES FROM BRIDGE SCOUR INSPECTIONS BY USING TWO ASSESSMENT METHODS ON 100 RAILWAY BRIDGES

This paper presents results of bridge scour risk assessment by using two qualitative methods. The first O'Connor Sutton Cronin method is based on a sum of parameters derived from flow charts taken from the Colorado method. The parameters describe general scour vulnerability, left and right abutments and the worst pier conditions, which are all evaluated by relative points. The output of the OCSC method is Vulnerability Ranking Score (VRS), based on which a Priority Rank for all bridges on a single railway line is given. The second Bekic McKeogh method was developed for Irish Rail on the basis of various standards and policies for scour evaluation. The output from the Bekic McKeogh method is a Priority Rating (PR), accompanied with the recommendations and a period for the next bridge inspection. Comparison of assessment results by using two methods are presented for loo railway bridges over the rivers and streams in Ireland. The paper in particular shows different assessment results obtained for three bridges, where results of both methods are compared and analysed in detail.