Cost Optimization in Bridge Construction:Application to Launched Bridges

Launched bridges are a usual typology for medium span length up to approximately 100 m. An important device in this construction procedure is the launching nose, a steel structure located in front of the deck and intended to decrease the bending moments of the cantilever portion of the bridge during launching. The research conducted by the authors on this type of structures was aimed to decrease the amount of material and, thus, the cost of the bridge. Two different problems were tackled. First, the length of the launching nose was chosen as the objective function with the aim to diminish the bending moment in the bridge. Secondly, an optimization problem was defined considering both the length of the launching nose and the internal dimensions of bridge deck as design variables and defining the weight of the bridge and the launching nose as objective function. To make it easier for practitioners to deal with this design procedure, a graphical interface was written and is also presented.