The Onondaga Community College is located approximately 20 miles south of Syracuse, New York. The two-year educational institution is best known in the region for its music program, which boasts faculty from the Syracuse Symphony Orchestra and the Society of New Music as well as a competitive indoor percussion ensemble. The school recently decided to build upon this reputation by constructing a $20 million, 45,000-square-foot addition to its Ferrante Hall building. International architecture firm Cannon Design designed the new structure, which is currently under construction. It features a 150-seat music recital hall, a music resource center, instrumental/choral and percussion rehearsal rooms, 20 practice rooms, 16 faculty office and teaching studios, and eight music-oriented smart classrooms.
Onondaga’s campus is split more or less in twain by a 60-foot-deep wooded ravine. In the school’s conception, the addition would run along the edge of the gully at Ferrante Hall’s western extremity. Cannon Design had another idea. Why not build the addition as a bridge across the divide and connect Ferrante to the Gordon Student Center on the other side? The solution would not only satisfy the institution’s programmatic needs, it would also provide a sheltered pedestrian link between the campus’ halves. As it was, Onondaga sufficed with an uncovered bridge that exposed its student body to the inclement elements of Central New York’s unforgiving winters.
The school liked the idea and Cannon’s engineers got busy working out a structural system capable of spanning the roughly 200-foot-wide abyss. While the design team explored many options, in the end it settled on a system of three 30-foot-high by 200-foot-wide trusses, built up from some of the largest rolled structural steel sections available, that support the building in a single clear span from bank to bank.
Due to the fact that there was limited staging space on either side of the ravine, the trusses were each prefabricated in two sections before being delivered to the site. A temporary tower was erected in the middle of the gorge and each section was lifted into place by a crawler crane. Once two sections were up, they were spliced together with 1½-inch A490 bolts.
The design of each truss was carefully calibrated to handle the deflection imposed by the building’s varied program. Since the recital hall is a single two-story space, that end of the structure needed to support less weight than the other end, which supports two one-story spaces and their extra floor. Deflection also posed another challenge. If the truss was loaded at the wrong moment it posed the threat of cracking the exposed concrete floors and shearing the curtain wall anchors. To safeguard against this, the construction team carefully sequenced the installation of the building’s elements and also pre-loaded the truss to neutralize deflections.
Architecturally, the bridge building makes a subtle reference to music. The curtain wall, which is made up of aluminum mullions filled in with narrow, horizontally aligned fritted insulated glass units, is punctuated with slatted sunscreens arranged in a pattern inspired by the pentatonic scale on a guitar fret board.
