New York, NY
706 Madison Avenue
The retail development at 706 Madison Avenue is five above-grade and two below-grade stories of new construction surrounding an existing landmark building. The project included preserving the two street-facing facades and a complete interior renovation of the 1920s bank building. SGH was the structural engineer for the project, including the retail fitout, and assisted with designs for below-grade waterproofing, limestone cladding, and cornices.
Incorporating the existing bank with the new building involved removing two facades and lowering the first floor to better match the street and new building. Highlights of SGH’s structural design for the existing building include:
- Removing the existing, deteriorated cinder concrete floor slabs at the second and third floors, while retaining the steel framing
- Replacing the second and third floor slabs with new concrete slabs to support higher live loads, allowing for more flexibility in using the space
- Removing and replacing the existing first floor framing
- Removing three columns in the first level to provide an open layout and resupporting the second floor framing with a system of transfer girders
- Repairing corroded beams and columns
- Evaluating the existing mat foundation for the new loading and advising the architect on ways to avoid overloading the mat and subgrade
We designed the new building structure comprising composite steel framing with a combination of moment and braced frames to resist lateral loads and a mat foundation to accommodate poor soil conditions. Our design included strategically placing framing and selecting the size and thickness of structural components to maximize usable space.
Our work also included tenant-specific structural design for the seven-level store. The structural modifications included reconfiguring the lateral system; adding floor openings and infill framing; and supporting new stairs, a skylight, roof terrace landscaping, mechanical equipment, safes, and an exterior sculpture.
SGH provided construction phase services, including observing ongoing work and helping address unforeseen conditions, particularly below grade. We also helped monitor adjacent buildings to track movements during construction.