Development and implementation of a bridge management system for South African road and rail authorities

Abstract

This paper describes a bridge management system (BMS) developed in South Africa for various road and rail authorities including the South African National Road Agency, Spoornet (the South African rail authority), the Cape Town City Council, the Botswana Roads Department and the Taiwan Area National Freeway Bureau. Each authority is responsible for the maintenance of its bridges which range in number from approximately 80 to 5 000. The system has been developed for assisting in the maintenance of bridge structures. The approach taken has been different from traditional BMSs. The inspection, condition and budget modules have been based on an innovative approach to bridge inspections. Each of the 21 predefined elements of a bridge are assessed in terms of the defects (rather than the overall condition) by means of a 1 to 4 rating for Degree, Extent and Relevancy (DER). Degree is defined as the severity of the defect under consideration; Extent is the extent to which the defect occurs over the area of the bridge element; Relevancy is the importance of the defective element on the serviceability and safety of the bridge. The Relevancy forces the bridge inspector to evaluate the consequences of the defect in terms of the bridge serviceability and safety. Each of these parameters is combined in the condition module to determine a priority ranking of bridges requiring repair. A remedial work sheet is used during bridge inspections to summarise the items requiring repair. Remedial work is identified with associated unit costs and this is used as input for the budget module. The DER rating enlightens the bridge manager about specific problems experienced on the bridge network.