Bridges are important links in our road infrastructure network, making it possible to carry all types of goods and creating economic growth. This is particularly the case for (some) long-span bridges that cross main rivers, and for which there exist no alternative. These long-span bridges are often composed of high concrete piers, and steel orthotropic decks, which permit big crossings. These types of bridges are sensible to specific parameters of the traffic, possibly reducing their residual lifetime when introducing new traffic management procedures. This is the case for platooning, where vehicles are closer to each other than regular traffic and whose lateral positions are aligned in the lane. After presenting the context, this paper will show the assumptions and boundary conditions for our work. Without big emphasis on the calculations themselves, we will give some results in terms of modification of the residual lifetime of these bridges.