On West 57th Street just a few feet east of Carnegie Hall rises the sumptuous new Metropolitan Tower, New York City's tallest residential building and tallest reinforced concrete building. With its observation deck at 716 feet, Metropolitan Tower claims the further distinction of being one of the world's ten tallest reinforced concrete buildings.
The unique building plan required some unusual structural engineering solutions. To absorb the weight and pressure of the tower and keep an efficient column grid on the commercial floors, a double-height reinforced concrete mechanical floor was created at the 19th floor to allow the transfer of loads from the triangular plan of the building's upper tower to the L-shaped base. In effect this was a new foundation for the triangular tower, accomplished by using an extraordinary volume of concrete, an unusually dense mass of reinforcing steel and beams up to 13 feet deep.
Choice of the supporting structure in concrete reflected needs of the extremely tall slender structure. When comparing buildings of structural steel and reinforced concrete having similar stiffness and movements, the perceived motion in the concrete building will be less because the larger mass of the concrete structure slows down its swaying motion.