A two-tone appearance created with textured and color-pigmented architectural precast concrete spandrels provides a distinctive look for the seven-story, 2,000-car parking structure for Partners Healthcare in Somerville, Massachusetts. The design was completed on a fast-track basis for the project, on which the precaster served in a design-assist role.
The project comprises the parking structure and an adjacent 850,000-square-foot building, which will become the home to employees currently spread through 15 locations. The project and supporting parking need to be ready when leases expire in 2016. “There was a 22-month window in which we had to design and build both the building and parking without any cushion for delays,” explains Todd Dundon, senior associate at Gensler, the architectural firm on the project.
The 750,000-square-foot facility features a total-precast concrete structural system consisting of pretopped double tees, girders, columns, shear walls, lite walls, spandrels, stairs, slabs, and wall panels. The aesthetic design consists of a smooth, light-colored “frame” around the outside of each face and on vertical columns within this frame, with thin vertical reveals used across all of the spandrels, creating two tones. Some of the panels feature both textures. Corners feature orange-tinted panels that replicate the look of terra cotta. Blakeslee Prestress fabricated and erected all of the precast concrete components.
“The precast concrete design was used primarily due to the speed of erection we could achieve and the long-term durability it provided,” explains Bryan Hilton, project manager for McNamara · Salvia, the structural engineer on the project. “The thought process was that we wanted the look of concrete and the long-term durability, and past experience with precast led us to that choice.” A number of other parking structures in the area also feature precast concrete designs, he notes, which allowed this design to blend with those.
The goal with the various textures and colors was to lessen the scale of the project while tying it more directly to the new building’s aesthetics, says Dundon. “The textured spandrels have a darker color that fades away, leaving the brighter frame more apparent.” This black-and-white format reflects the design of the building and its fenestration, he notes. The terra-cotta look at the stair towers reflects the use of actual terra cotta on the building. “We wanted to match the building’s look in a more economical fashion.”
The key challenge for the project was the aggressive schedule. The precast concrete components began erection eight months after the contract was awarded, with all pieces planned to be in place five months later. The precast is scheduled for completion in November, with occupancy in May.
“We crunched the schedule into a virtual design-build format,” Hilton explains. Blakeslee was brought on in a design-assist capacity, and the contracts were let to the firm immediately after completion. “We had them help with the design and they were awarded the contract to ensure the tight schedule could be met.”
The site is adjacent to an MBTA commuter rail line, requiring close coordination during erection, says Richard Pielli, project manager at Suffolk Construction, the general contractor. “We worked with the railway people to determine how we could maneuver the crane, since it couldn’t swing over the tracks.” That required all of the erection to be accomplished from one side. “We worked it out so the schedule could be met.”
A unique feature focused on the design of the stair towers at two corners. Surrounded on three sides by glass curtain wall, they present focal points that required a streamlined appearance while providing the structural support necessary. “We went through several iterations to achieve the final design, which Blakeslee suggested,” says Hilton. The structures feature two tree columns on each stair that allow the landings to cantilever off the columns and the stairs to wrap around the columns. This minimized the stairs’ thickness, creating a flowing design.
“It was an interesting and creative approach,” he says. “It opens up the view from the stairs and providing a sleek appearance from outside.”
Another challenge came in detailing all of the foundation connections, Hilton says. “We had to work through connecting the foundations with the above-ground walls smoothly, working through the key points with the cast-in-place wall widths, steps, and elevations. It wasn’t difficult, but it required close detailing for those connections.”
The result is a large structure that will open on time with a distinctive look. “Blakeslee pulled off the textures quite well,” says Pielli. “The custom-formed look created an interesting appearance that couldn’t have been achieved with flat spandrels. The more complex look provides a decorative appearance.” The two-texture pours for the panels reduced the piece count and speeded up the delivery and erection processes, helping the project meet its goals. |