Simulation Model for the Construction of the Alamillo Bridge

The Alamillo Bridge in Seville, Spain, was designed by Santiago Calatrava as a non-symmetrical cable-stayed bridge supported by a single pylon that rises at an angle away from the deck. This gives it the appearance of a harp, with the parallel cable stays serving as the strings that support the structure. It is the only bridge in the world with an inclined pylon that is not back-anchored and must balance over a massive foundation at the foot of the pylon. The original cantilever plan envisioned by Calatrava called for the pylon and deck to be constructed simultaneously and always to balance each other. This plan was abandoned by the contractor as it required the concurrent completion of all dissimilar components of the deck to provide the weight necessary to balance the advancing pylon. The contractor developed a second plan for bidding, and a third, more intricate plan for construction, to compensate for time lost due to additional design and stability analysis. This paper presents a simulation model for the plan used for construction. It describes in some detail the proper sequencing of operations necessary to complete the project within its engineering constraints and the allowed time frame. This model can be a practical example of applying discrete-event simulation to a challenging construction project.