A bridge structure this large requires a sturdy foundation. First, in mid-2019, piles were anchored in the ground. Equipment weighing up to 155 tonnes was used to drill holes 13 meters deep into the ground for them. It was a challenge for the construction workers, who had to control these enormous machines with surgical precision. The piles were then topped with special caps to create a base for the supports of the drive-by platform. A total of 70 of them hold up the bridge structure, 56 arranged in a straight line running east to west. Utility lines, sewers and so on pass through them.
The structural engineers had to meet special requirements while designing the V-shaped supports. A full-size test support was made first to make sure that they would actually perform as required and if so give the green light for work to proceed. Production of them began in the first quarter of 2020. The same sequence of three steps was followed for each one: place the formwork, mount the rebars, and then pour the concrete. Formwork and rebars were appropriately placed to create the special shape of the supports for the drive-by platform. Finally, self-compacting concrete was poured in from above. Due to the supports’ great height of about 10 meters, the entire process had to be meticulously recorded and monitored. The reason is that concrete is heavy, yet the pressure it exerts on the formwork couldn’t be allowed to exceed a certain limit. Once the first supports were finished, preparations for building the superstructure could begin. A total of 14 concrete sections with a length of 36 meters had to be made so that travelers and visitors would later be able to conveniently drive right up to the entrance of the main terminal building.
But why did Fraport choose the complex V-shape for the supports? Esthetic considerations were only secondary. The main reason is that this solution leaves more space underneath for vehicles to maneuver than conventional supports, which would have had to be placed closer together.
An elevated drive-by platform lets passengers arriving by car or taxi go straight to the entrance of the new Terminal 3 on the departures level. It measures more than half a kilometer long by three meters wide. The concrete for the individual sections was poured in shallow formwork basins. After it cured, the formwork was removed and reused for another section. The construction workers used so-called formwork wagons for this, in other words huge mobile support structures integrating all relevant parts for a section. The company of PERI supplied them for Terminal 3.