Constructed in 1966, Virgil I. Grissom School No. 7 is a three-story, steel-framed building, totaling approximately 68,000 square feet. To meet the target enrollment, additional classroom space was required. The project involved the construction of a third floor addition, approximately 9,700 square feet in size, on the west and south sides of the existing gymnasium along with a three-story stage area and classroom addition adjacent to the existing cafeteria. Despite being designed to accommodate a third-floor addition, the school was built prior to the adoption of seismic provisions in the New York State Building Code. Construction of the third floor addition would have required extensive, costly strengthening of gravity and lateral load-resisting systems, leading to the construction of a two-story, 7,700 square-foot structurally-independent addition.

Popli Design Group (PDG) provided structural engineering services to support the project.  Highlights include the following:

• Structural analysis of the school building determined potential impacts of the third floor addition, identify the need for structural retrofit of primary framing systems, and provide recommendations for structural reinforcing.

• Two-story classroom design utilizing a concrete-topped metal deck floor/diaphragm system constructed with wide-flange steel beams, metal deck and open-web steel joist roof framing, structural steel moment-frames, and concrete spread footings

• Modifications to second floor and roof framing to accommodate a proposed building entrance and clerestory roof, including the removal of one building column

• Design of a free-standing, self-supported steel-framed canopy (one-story height)

• Design of modifications to third floor and roof framing to accommodate a skylight

• Analysis of roof framing and design of supplemental steel-framed platforms to support two 30,000 pound rooftop air handling units

• Design of modifications to roof framing and wall construction at the gymnasium to accommodate a stage, creating a long-span truss utilizing existing upper and lower roof framing and interior building columns. Following installation of new web members and other framing modifications, the lower portion of two existing columns was removed to provide the desired stage space.