ABSTRACT
ABSTRACT Previous researches have shown that the material production stage and the operational stage of bridges (when traffic is affected by maintenance activities) are the stages which have the major impact in the lifecycle performance of bridges. In this respect, the use of high strength steel (HSS) in structures may represent a significant advantage since it usually enables to reduce the amount of material that is required for a structure to fulfil its function. Inmost cases, the reduction of material use and consequently the reduction of the environmental impacts due to the amount of steel produced, compensate the increase of the environmental impacts due to the production of high strength steels. However, increasing impacts must be considered, associated with larger alloy content and usually more complex process route than ordinary steel grades as well as with the reduction of the fatigue resistance of welded joints and additional stability problems. Hence, in this paper a comparative life cycle analysis is performed: a bridge made of standard steel grade S355 is compared with an equivalent bridge made of steel grade S690. The analysis takes into account the complete life cycle of the bridge and includes safety, environmental and economic criteria. The main goal of this comparative analysis is to show the advantages and drawbacks of the use of HSS.
