One of the biggest project challenges was to ensure that the existing structure could support the additional loads and reframing work while meeting strict New York City building codes.
“The building sits on transfer trusses on the third floor and those trusses are one-story deep. So, anything we did at the top of the building would be on those trusses,” said Mohammed Haque, the structural project manager for WSP, who oversaw all renovation designs. “We ended up verifying them several times to ensure they were still working in terms of strength and deflection. It is an old building and every building has a specific capacity. So if you keep adding load, eventually the numbers won’t work.”
To improve the building’s exterior aesthetics, Tiffany’s also wanted to remove the existing floors above the building’s eighth floor and add new ninth and 10th floors to create some special upper volume event spaces. Initially, the existing eighth floor was going to remain. But it was thick and heavy, and with everything else the client wanted to put in that space, it would overload the trusses.
“By removing that floor and installing a new one, we removed a lot of the excess load and were able to achieve the balance needed,” Haque said.
Long cantilever beams were also installed in both the north-south and east-west directions to accommodate column-free space in the upper part of the building. Temporary bracings were also designed to protect the building against lateral loads during the construction of the new three-story plus roof to achieve the column-free addition.
Today, a three-story glass structure known as “The Jewelry Box” occupies that space and will host special events and exhibitions. It includes wrap-around terraces and panoramic views of New York City. At night, it even lights up Tiffany Blue.