This Sunday, University of Phoenix Stadium in Glendale, Arizona will host Super Bowl XLIX. The stadium opened in 2006 and is home to the Arizona Cardinals, and the annual Fiesta Bowl. This stadium is unique for many reasons, the least of which are the 2007 Fiesta Bowl, famous for the game-ending statue of liberty play and ensuing marriage proposal, or the infamous “they are who we thought they were” game.
No, the stadium is unique because it claims two features that no other stadium in North America can. It is the only stadium on the continent with either a retractable natural grass playing field or an inclined retractable roof. These are two totally unique features to North American stadiums and it happens to have both.
The roof is just as, if not more, impressive than the field. The two roof panels are made of translucent “Birdair” fiberglass, positioned 206 feet over the field and weighing in at just over two million pounds combined. Two 87-foot high, 700-foot long trusses support the panels, which each roll 180 feet on steel rails in about 12 minutes. That’s a whopping 0.17 miles per hour.
Why is the incline of the roof so innovative? It allows the roof to generate and store energy through a winding spool mechanism designed by BuroHappold and built by Walter P. Moore engineers. Also, the roof was constructed on the stadium floor and lifted in one piece to the top of the stadium. That was the largest ever lift of its kind:
The retractable field travels even slower than the roof, moving 741 feet in about 75 minutes. It may come as a surprise to you that the field is much heavier than the roof, at around 19 million pounds. That is because, at 94,302 square feet, it has a higher surface area than the roof, and its tray holds a draining mat, extensive irrigation system, and over three feet of sod. If you were curious, the stadium’s website states that the grass is Tifway-419, which is a Bermuda Hybrid.
While the retractable field is certainly an innovative feature, it is also a necessary one. Because of Glendale’s hot, arid climate, the plan was to build an indoor stadium from jump street. In fact, the stadium’s air conditioning system allowed the Cardinals to play their first season opener at home since they moved to Arizona in 1988. While the Cardinals’ ownership, which contributed $143.2 million to the $455 million site, wanted to have a natural grass playing field, the stadium’s alignment wouldn’t allow enough sunlight in to grow natural grass.
So, the stadium’s engineers looked to the GelreDome in Arnhem, Netherlands and the Veltins-Arena in Gelsenkirchen, Germany, two football, er, soccer stadiums with retractable pitches, er, fields. The retractable field is typically kept out until an hour before the game to ensure it receives an adequate amount of sunlight.
In addition to the field’s ability to absorb sunlight, the retractable field allows for University of Phoenix Stadium to host other high-intensity events without compromising the integrity of the field.
Some notable events that the stadium hosted include a Rolling Stones concert in 2006 and WrestleMania XXVI in 2010. Not to forget the community in which it does business, University of Phoenix Stadium also hosts many high school graduations.
Naturally, the stadium and the field have won multiple awards for being the best in the NFL. The field was named the best playing surface in the NFL by the Players Association (NFLPA) in 2006 and 2007, the best new venue of the 2000s by Sports Illustrated in 2010, and the sixth best sports facility in the world by Business Week in 2006. It was the only American venue on Business Week’s list of the top ten sports facilities in the world.
While playing surface and stadium seating capacity are limiting factors for many stadiums around the NFL to hold the Super Bowl, University of Phoenix Stadium clearly does not face these problems. When the Seattle Seahawks and New England Patriots suit up on Sunday, it will be the second time in eight years that the stadium hosted the Super Bowl. Not bad for a stadium that’s been around for less than nine years.
Jeff Horwitz will graduate this spring from the Masters of Urban Planning and Policy program at the University of Illinois at Chicago. His concentration is Transportation, and he currently interns at an affordable housing consulting company. Feel free to email him or chat with him on Twitter about Stadium innovations and advancements in sports.