Bridges are vital objects in public road networks. They should be managed to ensure that they result in minimum costs for all stakeholders, e.g. intervention costs for the owner and travel time costs for the user. An important part of bridge management is, therefore, the determination of the optimal interventions to be executed on a bridge over its life cycle, i.e. the optimal life-cycle activity profile, which adequately takes these costs into consideration. This is challenging as some of the costs to be considered are related to the condition of the elements of which a bridge is composed, whereas others are related to the performance of the structure as a whole and only indirectly to the performance of the individual elements. Among the methodologies developed recently, a few have the potential to overcome this challenge. In this paper, the possibility of using two state-of-the-art methodologies and a state-of-practice methodology to determine optimal life-cycle activity profiles are investigated. This is done by using them to determine the optimal life-cycle activity profile for a multi-span weathering steel girder bridge. The strengths and weaknesses of each are discussed.