are placed on concrete footings that rest directly on the bedrock, while the shear walls and columns on the southern and western boundaries are placed on concrete caps above the caissons. The basement story is composed of a concrete slab, while the ground story is made of a concrete slab. Superstructure The main contractor for the superstructure was Lendlease. The floor slabs for 53 West 53 are generally made of cast concrete thick. While most of the tower's support columns are along the tower's perimeter, there are also some interior columns. Steel trusses transfer loads from the interior columns to a shear wall core along the eastern edge of the tower. The northeast corner of 53 West 53 also includes a cantilever above an emergency electrical generator owned by Con Edison. A portion of the MoMA space, on floors 2, 4, and 5, is supported by two columns, one of which is a steel column measuring . Massive steel trusses on the sixth and eighth stories (floors 6 and 12, respectively) divert the loads above the MoMA space. There is a crawl space measuring high above the 5th floor. Above that is a mechanical story with separate sections for MoMA and the residential units. At the 35th through 37th stories (floors 45 through 47, respectively), a outrigger wall runs around the tower, connecting the diagrid and shear wall. Mechanical rooms are placed within these floors, dividing 53 West 53 into two segments with separate electrical, mechanical, and plumbing systems. One mechanical system serves the floors above these rooms while the other system serves the floors below. There are five steel spires above floors 21, 24, 73, 83, and 86; their steel construction allowed greater flexibility for constructing the roof. To stiffen the top of the building, the 73rd, 74th, and 76th stories (floors 83, 84, and 86) consist of concrete slabs. A tuned mass damper was installed in the double-height 74th story to provide stability against high winds or earthquakes. Interior 53 West 53 has a total floor area of approximately . The building is mixed-use, with condominiums, museum gallery space, and a private restaurant at the base. Three of the lowest stories are used as MoMA gallery space. The tower has four passenger elevators; two serve the lower residences on floors 12 through 40, while two serve the upper residences on and above floor 48. All four elevators serve