Volume 48, Issue 3- March 2013
Stairway to Higher Learning
In a college education, as they say, learning takes place as much outside the classroom as it does inside, but students at Drexel University in Philadelphia will be forgiven if they don’t realize the importance of something as innocuous as the staircase. It stands as a physical reminder of the building blocks of daily life for those who frequent the Constantine N. Papadakis Integrated Sciences Building, home of the school’s biology department.
Anvil Craft Corp., a family owned business in Easton, Pa., designed, engineered, fabricated and erected a four-story, self-supporting helical staircase with glass guardrails and stainless steel handrails. Completed in 2011, the staircase is “meant to evoke the structure of DNA.” Diamond Schmitt Architects of Toronto was the project architect.
The project was the second largest Anvil has ever undertaken, and one of the most challenging.
“The biggest part of the challenge was the logistics from getting things from all parts of the country and installed within the time frame the client needed. The stairwell itself had four different sections, each weighing about 17,000 pounds,” says Anvil’s executive vice president Paul T. Sklodowsky. “We had two cranes, one outside to orient it and back it into the building and a second one indoors getting it set into place. The glass itself came from Arkansas where Precision Glass Bending bent it for us. After all the stairs were set we had to mark them and do mock-ups, get the right measurements and then we could move on to the glass installation.”
“Drexel University required ¾-inch (19-mm) curved panels with a radius of curvature tighter than that which is typical for extra-heavy, bent tempered glass,” says Russ Alder, vice president of Precision Glass Bending, who says they worked with Pilkington glass for the job.
And though it was a challenge, it was one Alder says his company was up to tackling.
“Our company has long been known for bending and tempering radii as tight as 12 ½-inches and sloped parallelograms with as steep as a 60 inch rise,” Alder explains. “A couple of years prior to this project, we had been approached by Inkan Glass Ltd. of Canada to push its parameters for a project at Genzyme in Allston, Mass. Inkan required ¾-inch panels to be bent tempered to a 16 ½-inch radius sloping up 46 inches on the rise. This resulted in the pioneering of new techniques which force extra-thick panels into radii that were beyond the parameters thought possible and marginal even in simple laminated annealed glass. These new techniques afforded the confidence to take on the glass required by Anvil while maintaining super-tight tolerances without twisting the pieces out from the axis-of-bend.”
Add to this the need to finish on a very specific time frame and it becomes a challenge for everyone involved. Alder says his company’s main concern was fulfilling the expedited schedule Anvil required.
“Anvil needed to complete its project for Turner Construction prior to the start of the school year. This compressed schedule afforded us three weeks to complete successive releases of ¾-inch bent tempered safety glass,” says Alder. “Fabrication processes required included CAD drawings, approvals, cutting, polishing, drilling, CNC five-axis milling of cutouts, bent tempering and finally delivery of the glass to the jobsite. All products were delivered ahead of schedule, without error, and to the customer’s satisfaction.”
Sklodowsky adds, “We’ve done curved stairs before, but never of this magnitude and one on top of another and making all the pieces fit together—we did everything from detailing of the stairs, designing, engineering and load calculations that were then forwarded to the architect and engineer for approval. It was stressful, but it was a good accomplishment. It was hard at the time, but looking back, it wasn’t as bad as it felt at that time we were doing it.”
Brigid O’Leary is a contributing writer for USGlass magazine.