The building is cantilevered into a section of 420 million-year-old limestone bedrock underground. It uses -wide stilt-like pillars that were drilled beneath the building. Every around its perimeter, steel-reinforced concrete was poured into these holes to form the structural support. On top of these caisson shafts and pillars, an concrete pad foundation was built to support the building's spine. The building has 241 caissons, and the majority of the caissons only descend into hard clay. However, 57 of them go an additional into the ground, including of bedrock. The concrete spine uses five I-beam-shaped walls and exterior columns, narrowing to two as the building rises. Each floor is separated by a concrete slab, and stainless steel, glass, and aluminum panels are attached to each floor. of reinforcing steel bars, called rebar, support the hotel. The extensive use of concrete makes the building more fireproof. Of the $600 million construction budget, $130 million was earmarked for the James McHugh Construction Co, who handled the concrete-only portion of the job.