The new viaduct over the Cadiz Bay includes a removable deck to allow the navigation of large floating structures, higher than the 69 m clearance of the main cable-stayed span of the bridge. For this purpose, a 150 m long simply supported span was designed, which can be assembled and disassembled. The steel deck, weighing 4,000 metric tons, was completely manufactured onshore, the challenge being to move such a massive structure to its final position above the piers. It required for several heavylifting maneuvers, such as land transportation and load-out with two 6 x 28 axle lines of self-propelled modular transporters (SPMTs), sailing with a 100 m long barge and positioning the deck in-between the piers with a tight gap, a lifting with eight strand jacks 850 T capacity each and a final transversal shifting. The aim of this paper being to describe all the activities and the heavylifting equipment employed for the assembly of such a massive deck.