On solid ground

Long before a skyscraper takes shape, the foundation has to be planned and excavated. First the ground must be surveyed, taking into account not just its composition but also the likelihood of earthquakes, which can be compensated for by installing seismic dampers. A pit is then dug, which can extend up to five floors, into which vertical piles or reinforcing rods are sunk, securing the substructure into the bedrock. Typically this substructure is made up of vertical columns resting on cast-iron plates which sit on top of a grillage of horizontal steel beams. The substructure spreads out like a pyramid below the ground, distributing the enormous weight, and is encased in concrete. Only once the foundation and substructure are complete can the superstructure be lifted and secured onto it, allowing the rest of the construction to begin.