465 New York Avenue, N.W., Washington, D.C.
Holbert Apple Associates provided structural engineering services for this new 13-story cast-in-place concrete hotel structure, with 2½ levels of below-grade parking, located three blocks from the Walter E. Washington Convention Center. The Main Roof and typical hotel floors consist of post-tensioned concrete two-way slabs. The lower levels and below-grade levels consist of mild-reinforced concrete two-way slabs and beams. Six cast-in-place concrete transfer girders were designed at the 2nd Floor to accommodate the Ground Floor architectural program and below-grade parking. The building foundation consists of a stepped 36” thick cast-in-place concrete mat with 12” drops, which covers the entire footprint of the building. The structure was designed to support an intensive green roof at the 2nd Floor Low Roof and an extensive green roof at the Main Roof. The facade consists of a mixture of brick masonry and curtain wall systems.
In addition, Holbert Apple Associates performed structural engineering services required for the relocation of an existing historic, 112-year-old, three story brick bearing wall and wood-framed building from the southeast corner of the site to the southwest corner of the site. The historic building was temporarily braced internally and externally and then raised on steel framing with a custom unified hydraulic jacking system. The historic building was then moved approximately 100 feet on a series of pneumatic tire dollies and then supported on a temporary steel pile foundation/framing system, designed by a specialty foundations engineer. This allowed for excavation of the site to occur beneath the historic building and for the new below-grade parking garage and hotel building to be constructed below, around, and above the newly relocated historic building. In the final condition, the temporary steel pile foundation/framing system was removed and the historic building was supported by the cast-in-place concrete hotel structure placed below. The building relocation was primarily performed to help maintain the historic setting of the low-rise neighborhood on the west side of the site.