The height of the tower was driven by the goal of attaining 2,000 rooms within each of the hotel towers. With a long, thin profile and considering its location along the hurricane-prone coastline, foundation loads were significant. Wind tunnel analysis proved that required design wind loads exceeded that prescribed by the Code for both the main wind force resisting elements and the façade.
A Key foundation consideration was the capacity of the deep pile system. Building a 735 foot tall concrete tower in Atlantic City required new ideas for construction. Geotechnical analyses and preliminary pile testing resulted in the use of 22 inch diameter auger cast piles, a size that had not been used in Atlantic City. Mat foundations up to 17’-0” thick were required due to significant overturning forces at the base of the towers.
For foundation, concrete strengths were kept to 6,000 psi in the mat to minimize heat gain. Thicker than anything constructed in the city, mock ups were done to test heat gain and loss before advancing to final construction. A high (75%) slag mix in the concrete was used to control the heat. Cast in the middle of winter, embedded thermo couplers continuously measured the concrete temperature in the final construction. Output was reviewed and graphed to verify that the results fell within ACI limits.
Three 4’-0” thick concrete mega walls provide the lateral stability and dynamic acceleration control required for the tower. Concrete strength of up to 14,000 psi was specified and achieved. The tower wall elements have 27,500 cubic yards of concrete and 5,000 tons of reinforcing steel, with #18, Grade 75 reinforcing bars with mechanical splice couplers required at the lowest levels. The grade 75 reinforcing steel saved 10% of the reinforcing, thus reducing congestion. The project monopolized the availability of #18 reinforcing steel and couplers in the country.
There are 54 supported Filigree concrete framed floors in the tower that are 10” thick. Flying truss shoring systems were used on the hotel levels. For the lower floors, column hung shoring systems were used. 43,000 cubic yards of concrete were poured with 4,600 tons of reinforcing steel for the floor framing. Speed of construction was enhanced by using factory cast Filigree shells. The precast shells were pre-stressed and reinforced, reducing the quantity of field placed reinforcing steel in the slabs. The shells are cast with a foam void where solid concrete is not required for strength. This in turn reduces the volume of concrete and weight of the overall tower.
The low-rise entertainment and casino portion of the project is a steel structure outside of the footprint of the two towers, which includes 150,000 square feet of casino, 500,000 square feet of dining, retail, health spa and entertainment venues including a 5,500 seat performing arts center. The unique layout of the complex required more than twenty five separate transfer trusses over the drive entrance, open spaces and the performing arts complex with spans from 150 to 200 feet.