Levi’s Stadium opened in August 2014 and will serve as one of the world’s best outdoor sports and entertainment venues. Replacing the antiquated Candlestick Park, the stadium in Santa Clara, Calif., is the new home of the San Francisco 49ers and will also be used for college football, soccer, motocross, concerts, and civic events.
The new stadium is designed to be light, airy, and open. The attractive white, painted steel structure creates a unique viewing experience. With the exposed steel, special attention was given to carefully fit all stadium systems within the alignments of the structure to keep the aesthetics clean.
Precast producer Clark Pacific, based in Woodland, Calif., manufactured 40 million pounds of precast concrete for the project. Clark Pacific produced the precast concrete at its Woodland plant from April 2012 to May 2013. The 49ers’ stadium features 2,000 precast panels (risers and walls), with each concrete panel ranging from 20 feet to 40 feet in length and weighing up to 35,000 pounds.
This meant it was necessary to be able to easily strip all of the stadium’s forms and formliners. These included forms for panels for the field; lower, mid, and upper levels of the stadium (single, double, and triple risers); and all vomitory wall forms—an integral part of a stadium’s viewing aesthetics. Precast crews used backpack sprayers to apply the release agent (Crete-Lease 880-VOC-Xtra by Cresset Chemical) at 0.067 gallons per minute at 40 psi.
For best results, form surfaces were cleaned and dried before spraying. An ultra-thin film (0.0005 inches thick) was applied to get a CCS1 finish that promoted easier stripping, less form clean-up, and the complete elimination of discoloration, dusting, bugholes, and concrete build-up. After spraying a fine mist, workers simply wiped them down evenly with a rag that was damp with the release agent. If puddles formed, they simply wiped them off.
“We specifically chose Crete-Lease 880-VOC-Xtra because it is safe to handle and use, cleans up well, is easy to apply, and provides consistent results,” said Ryan Nakken, Clark Pacific’s assistant Woodland plant manager. Cost savings are “simply built into the process because our panels release from the forms easily, the forms stay clean, and the panel finish is not affected,” he added.
Additionally, regular use of the product keeps forms clean when used on nonpourous forms and formliners made of plastic, elastomeric (urethane and silicone rubber), steel, high-density plywood, and medium-density plywood overlays. It will not stain or stick from heat curing, and doesn’t interfere with adhesion of caulk, architectural coatings, paint, sealers, and curing compounds on cured concrete surfaces.
LEED Gold status
The Levi’s Stadium project also boasted a unique “green-focused” philosophy, with an eye toward sustainability as the stadium incorporates photovoltaic panels, a green roof, water-conserving plumbing, sophisticated building control systems, and recycled materials. Levi’s Stadium is the first new NFL stadium to achieve LEED (Leadership in Energy and Environmental Design) Gold status.
The intent of regulating VOCs is to reduce the amount of ozone produced at ground level. EPA mandates form release agent manufacturers to meet the VOC criteria. While the standard allowable amount of VOCs is 450 g/L, more stringent standards are emerging in states such as California, which requires a 250 g/L standard. Crete-Lease 880-VOC-Xtra meets that requirement at 240 g/L.
So if you go the Levis Stadium for a 49ers game or another event, pay close attention to the precast concrete. If you don’t see it in person, the stadium will take center stage when it hosts Super Bowl 50 in February 2016.