opposite page: The completed 14-story, 524,838-sq.-ft SORA West office building (at right in photo). below: Five braced frames were used to laterally brace the 184-ft-tall structure. Mal Bland ONCE A THRIVING STEEL MILL TOWN, Conshohocken, Pa., has long been an area in transition. Its proximity to Center City Philadelphia—a 15-minute drive—and accessibility to mass transit has perpetually made it an attractive commercial hub, but up until recently, growth had been haphazard. “Conshy,” as the locals call it, lacked a town center, and little thought had been given to walkability or parking. Keystone Development + Investment had a vision to change that and proposed SORA West, a multi-use complex that includes a new 14-story office building, a hotel, a parking garage, and a his-toric firehouse adapted into a restaurant, all built around a public plaza that hosts concerts and other events. At the same time, pharmaceutical distributor AmerisourceBer-gen wanted to combine two locations into a single headquarters and increase its brand identity. The company, with a top ten rank-ing on the Fortune 500 list, studied labor conditions, trends, and workplace dynamics and chose Conshohocken and SORA West as its new corporate home. The company’s 1,500 Pennsylvania-based employees have recently moved into the 14-story, 524,838-sq.-ft office building, which was completed in late 2021. The space offers 11 floors of collaborative office space, including the lobby and ground-floor amenities; a two-level, 76,372-sq.ft basement parking facility with 173 parking spaces; a 16,000-sq.-ft rooftop terrace with a mechani-cal, electrical, and plumbing penthouse; and a high roof. The chosen framing material for a project that reimagines a steel town? Steel, of course—3,500 tons of it. “Structural steel allowed earlier design of the base structure so an early bid package could be issued,” said Mal Bland, PE, principal and project executive/operations manager for IMEG (formerly The Harman Group), the structural engineer of record for the core and shell. “This allowed the structural steel fabrica-tor to begin their work earlier. The base structure is normally on the critical path, so accelerating the steel fabricator and detailer results in an earlier turnover to the developer. In turn, this allows the developer to deliver the core and shell of the building to the corporate tenant sooner.” “The use of steel allowed an efficient column grid of 30 ft by 45 ft that works well to maximize the efficiency of office layouts for corporate office buildings,” Bland continued. “And the use of structural steel resulted in approximately $20-per-sq.-ft savings in the structural cost.” The site presented several challenges that the design team of IMEG, architect Gensler, and general contractor Intech were able to solve using the structural steel with slab on metal deck building, including working with a difficult slope and maintaining the dura-bility of the steel-framed parking levels in the basement. Five braced frames were needed to laterally brace the 184-ft-tall structure—three in the long direction and two in the short direction. The braced frames, mostly made up of W14 wide-flange chevron braces, were strategically placed within the interior of the floor plates, next to the stairs/eleva-tors, to maximize open floor space and to offer unobstructed views around the perimeter of the building. To limit the lateral drift, moment frames were placed at the far ends of the build-ing. These frames used partially restrained beam-to-column moment connections to keep service-level wind drift values within a code limit of H/400. Modern Steel Construction | 33
Modern Steel Construction January 2023: Page 33
