"One of our primary concerns was thickness," recalls Aulikki Sonntag, Roschmann engineering and design director. "We needed to ensure the wall's glazed members weren't too thick or stiff to resist bending. On a more conventional assembly, we would have started with 1/2-inch-thick inner and outer members. Here, we specified a pair of 1/4-inch members with about a 1/2-inch air space between the two."
As designed, no two glazed members are identical, the result of alternating convex and concave forms along the wall's horizontal axis, in addition to varying inclines along its vertical axis, according to Sonntag.
"We refined a lot of details for those trapezoidal elements during modeling," says Myer. "Stantec and Pelli Clarke Pelli executed the design in Revit, which we adopted as well."
In all, the assembly required fabrication of 67 frame elements, each containing three to four glass panels.
Prior to their assembly, mock-ups allowed project team members to evaluate the degree to which glazing could withstand pressures from cold-bending without breaking. Likewise, silicone sealants were tested to the point of failure.
Project team members also employed mock-ups to thermally and structurally evaluate the wall's steel framing system and determine how workers should sequence installation of finished members when they arrived on site.
One-in.-thick glazed assemblies arrived on site in 2-ft-wide-by-3-ft-tall and 2-ft-wide-by-6-ft-tall sections, with installers employing networks of internal toggle bolts to achieve the desired curvatures. "We essentially were bending the glass as we installed the toggle bolts," says Myer. "We worked on two opposing sides at a time, working from one corner to the next. It's not entirely unique, but it's unusual. Not every installer has that expertise."
Concerns ranging from logistics to quality prompted Gilbane to prequalify contractors for mechanical systems and lab furnishings as well. "Mechanical, electrical and plumbing for the labs are all specialty packages," says Myer. "Some firms have those capabilities on their resumes; some don't. One area of particular concern with chemistry and research labs is proper exhaust from the fume hoods and fume extraction arms."
"So often you associate construction sites like this with the smell of burning metal," says Constantino. "Here, welded stainless-steel ductwork for lab spaces is being fabricated off site." The same is true of lab racks and casework.
The completed facility will feature a four-story lab and six-story office structure joined by pedestrian bridges at the second, third and fourth levels, a configuration that yielded substantial savings. "A stand-alone office building is cheaper to build and operate," says Reagan, who notes Pelli Clarke Pelli developed alternatives that would have located lab and office spaces under a single roof.