A bridge management system applied to a set of Portuguese bridges
Portuguese people still haven't forgotten two important accidents occurred with two bridges recently, one in Entre-Os-Rios and another in Lisbon. In fact, the problem is that some other bridges can probably be near the end of their structural or functional period of life now. Therefore, it's urgent to identify those cases and act according to the urgency of intervention. The guarantee of safety is hardly assured when the reparation works are only implemented if someone, more or less accidentally, notices some damages and alerts to them. In fact, it is urgent to implement a regular inspection on bridges and then treat all the gathered information in order to plan the needed intervention. Besides, it is necessary to do an exhaustive analysis that could assign the real urgent and essential actions. The implementation of Bridge Management Systems is being recognized as a good way to systematize all that process and minimize the ratio cost/benefits during bridges' life time. To help in the process of inventory and appraisal of a group of highway bridges, a Bridge Management System tool, called REGpontes, was developed by Almeida (2003), using a methodology of classification from USA (FHWA 1995). The referred methodology of classification includes the determination of four partial ratios: structural adequacy and safety (R1), serviceability (R2), essentiality for public use (R3) and special reductions (R4). Those ratios are then balanced, taking into account their relative importance (55% of R1, 30% of R2 and 15% of R3), to calculate a global efficiency ratio. That final ratio can then be very useful to analyze the global situation, to identify intervention priorities and to program the needing for repairing, strengthening and rehabilitation works. The results of its application on a set of Portuguese highway bridges are presented in Figure 1 and in Figure 2, taking in consideration the relation between the gathered ratios (converted in a 0 to 100% scale, from worse values to better ones) and the main structural material or the major dimensions of the bridges. The global efficiency of the analyzed bridges, in average terms, is almost fifty percent. Analyzing the average obtained for each one of the partial ratios, it is possible to conclude that the selected bridges are better in structural terms and worse in serviceability terms. The reason for the serviceability insufficiency is mostly related with deficiencies associated to traffic circulation, such as the narrowness of the road face, the volume of traffic, which mainly, results from the oldness of the selected bridges. The utility for public use, which represents the strategic value of the bridge and its importance because of higher daily traffic and/or a long detour length, is the ratio with a bigger standard deviation. In terms of structural adequacy and safety, the metallic bridges present a lower value, mainly because of deficiencies in maintenance. In Portugal there is a lot to do and it is urgent to act. REGpontes is an informatic tool especially developed to guide the management of Portuguese highway bridges. From the presented example of its application it's possible to see that the methodology inherent to the program can be easily adopted with great benefits. With REGpontes, the technical and political decision can be objectively supported. © 2006 Taylor & Francis Group.