WHOLE LIFE COSTING IN ROAD BRIDGES APPLIED TO SERVICE LIFE PREDICTION Bridge engineering and economics J. DE BRITO and F. A. BRANCO IST, Technical University of Lisbon, Portugal Abstract Functional performance is measured through a long-term economic analysis. In this paper, a whole life costs function intended for concrete road bridges is presented, in which all costs and benefits obtained from each bridge included in a road network from the design stage to its replacement / demolition are considered. The use of the function is exemplified by a case study in which the widening optimal time is obtained for a bridge showing deterioration of its level of service. Keywords: bridges, deck widening, functionality, long-term costs analysis, service life. 1 Introduction All technicians involved in the design of a bridge within a road network must keep in mind that the final goal of their work is to provide a facility during a certain period, the service life, taking into account the predicted characteristics of the traffic in terms of volume and weight. The need for such a facility is usually related to global economics, structural safety and architectural design being just important means to achieve an end. Therefore, the global design of a bridge must try to maximise the benefits obtained from its construction by society in general and minimise all costs involved, from the initial costs to environmental and visual damage to the landscape. Even though some of these are quite difficult and sometimes arguable to quantify, tools must be created to perform long-term economic analysis at the design stage. In such a task, there are several difficulties, besides the ones related to non- economic entities like life quality and environment preservation. Traffic predictions