550 Madison Avenue, Repositioning

overview

Designed by Philip Johnson and John Burgee of Johnson/Burgee Architects, 550 Madison Avenue was completed in 1984 to serve as the AT&T Corporate Headquarters building. The 37-story pink granite office tower is an icon of postmodern architecture, with design elements including a massive Chippendale-style pediment and a 110-foot-tall entry arch. The State Historic Preservation Office has stated it “is of extraordinary national importance as one of the key exemplars of Postmodernism” and, as such, it was designated a New York City landmark in 2018, just before the owner embarked on a renovation and repositioning project to revitalize the aging structure into a modern workspace and public amenity.

We provided structural design, façade engineering, specialty structural design at the canopy, FISP, envelope renewal and historic preservation services for the project. Snøhetta is the design architect for the tower repositioning and the garden, while Gensler led the lobby design and Rockwell Group designed the amenity levels. 

The project included updating an existing and underutilized Privately-Owned Public Space (POPS) into a year-round garden to create an inviting and inclusive space for both tenants and community members. A line of white steel columns rises from the garden to meet and support a sweeping glass and steel canopy, and rounded forms including blond-wood tables, benches and concrete planters play off of the structure’s flowing form.

The redesigned lobby of 550 Madison Avenue introduces a new level of transparency, featuring a soaring 30-foot-tall arched picture window that allows pedestrians to see through the vaulted entrance, past the lobby and into the public garden beyond. This transformation was made possible by relocating the existing shuttle elevators and creating a large arched opening in the rear shear wall, replacing the once-opaque facade with a direct visual connection to the outdoor space.

highlights

• Our structural scope for the tower included upgrading the lobbies, amenity spaces and tenant floors, removing interconnecting non-egress stairs and designing structural support for revised elevator stacking and mechanical systems.
• In the plaza, our structural scope included replacing the barrel arch atrium and four-story annex with a stepped and sloping concrete structure supporting landscaping, three kiosks and a steel and glass canopy.
• We also provided structural support for the 50,000-pound Azul Macaubas stone sphere designed by Alicja Kwade that measures eight feet in diameter and hangs 12 feet above the lobby floor. It is suspended from the reinforced ceiling by ten polished stainless-steel chains, each measuring 60 feet long.
• We modified 24 steel-plate outriggers on three levels to provide an open layout across the floors. A new 30-foot-tall arched shear wall opening at the lobby offers views of the plaza through a glass picture window.
• Our façade services included the restoration of the existing façades, new windows and glass façades on public levels and design for the new glass canopy. We coordinated the design of the 12,000-square-foot glass canopy on slender steel columns that partially covers the public garden.
• The construction sequence of the canopy was built into the design to follow a modular bay-by-bay installation sequence. This allowed each bay to remain self-stable while the subsequent bays were being built.
• Our façade engineers also designed a new slender T-shaped steel mullion storefront façade set into existing 60-foot-tall openings. Double-laminated, stepped insulated glass units with recessed pressure plates create a seamless plane within the monumental granite portals. We designed new glazed systems for the historic porthole openings, as well as new large format punched windows at the lobby level and replacement of the existing glazing on the upper floors.
• Our envelope restoration scope included designing stone repairs to the historic Stony Creek granite and filing FISP reports. We specified several options to clean the facades, which were then tested in pre-construction mock-ups. The results confirmed that low-pressure micro-abrasives was an effective cleaning method which did not damage the historic stonework.