Prefabrication Realizes its Potential: Rainier Square, Seattle
Session: Track D: Structural Engineering Award: Part 2 & Innovation Award, Part 1
Vice President, Wright Runstad & Co
Chairman, CEO, Magnusson Klemencic Associates
Rainier Square, Seattle, uses SpeedCore—a novel and innovative structural steel system comprised of modular, prefabricated, concrete-filled, composite-plate steel shear wall (CF-CPSW) panels—which helped create the high-rise tower’s structural core quickly and cost-effectively. The swift construction sequencing involved prefabricating more than 530 plates, which were then pre-assembled in connected pairs to form modules ready for site installation and concrete fill. The panels were fitted with openings for MEP services, penetrations for fire protection pipes, and connection materials for field-attached floor beams. The second step was the transportation and placement of the steel modules. Once assembled, these modules were stacked onto trucks, transported to the construction site, hoisted into place, and field-welded. The third step was a concrete-filled core “sandwich.” As the panels were erected, concrete was pumped into each module, resulting in a configuration with steel panels on the outside and concrete filling the inside.
SpeedCore is a faster way to build a structural core, as it eliminates the time-consuming choreography required by the setting of formwork, installation of reinforcing steel, placement of embedded plates, and level-by-level concrete curing. Its assembly line-like efficiency allowed the project’s construction to proceed 43 percent faster than conventional methods, cutting 10 months off the original 32-month schedule.
SpeedCore also embodies sustainability in several important ways. It reduces the amount of raw material typically needed to construct a conventionally framed high-rise building, thereby reducing the project’s environmental impact. Material resources such as rebar, steel embedded plates, and disposable formwork are not needed. By dramatically shortening the construction schedule, a substantial reduction in embodied carbon is realized through the elimination of construction activities, truck trips, temporary operations, and general overhead.