Building a super bowl

November 1, 2013 by Nate Seltenrich

This article appeared in Berkeley Engineer magazine, Fall 2013

The screams of roller coaster riders, drifting through open windows, often interrupt midday meetings at the construction trailer offices at the Levi’s Stadium site, a few hundred feet west of the Great America amusement park in Santa Clara. Not that this has slowed progress. To the north, those same windows now frame a stadium that looks nearly complete, its massive outline against the sky—scoreboards and loudspeakers, light assemblies, nine-floor “suite tower,” tri-level seating bowl—in final form.

Only 14 months ago, this was just a flat, concrete expanse at the fringe of Great America’s parking lot.

“Every time I come over here I’m amazed at the progress,” says Kesor Kim (B.S.’05 CE) during a stroll through the stadium’s labyrinthine hallways and concourses. As mechanical, electrical and plumbing (MEP) manager for the project’s design-build contractor, Turner/Devcon, Kim spends much of his time in an office in one of those trailers. He relishes the opportunity to lead a visitor through what is fast becoming an industry-leading structure—and, it was announced in May, the future home of Super Bowl L.

Constructed in record time, Levi’s Stadium, the new home of the San Francisco 49ers football team, will feature such state-of-the-art technology as high-definition scoreboards and seamless Wi-Fi access; solar panels, reclaimed water and a green roof for energy efficiency. (Illustration courtesy Turner/Devcon)

Levi’s Stadium, named for the famous San Francisco denim company, will be the first new National Football League (NFL) stadium in the Bay Area since the Oakland Coliseum went up in 1966, as well as the largest stadium of any kind in the region, and, at $1.2 billion, certainly the most expensive to build.

Within the belly of the 1.8-million-square-foot structure, it’s easy to see the shape of things to come. A model five-window concession stand—painted, lit up and waiting like it was opening day—sits incongruously among unfinished concrete-block walls and exposed steel framing. The scent of mustard and onions doesn’t feel so far off; one imagines the broad concourse outside bustling with red and gold.

But the best view—of the stadium-in-progress and of the entire Santa Clara Valley—comes from floor nine, the suite tower’s rooftop deck and future home of an 18,000-square-foot green roof—the NFL’s first. The roof will hold a 12,000-square-foot photovoltaic array that, together with additional panels below, should generate more than 530,000 kWh per year—enough, the 49ers estimate, to cover the energy consumed in the stadium during all ten home games each season.

Thanks to these and other green elements, the stadium is on track to be the NFL’s first certified LEED Gold, and the first to receive any LEED rating upon construction.

Despite such extra features, it will also be among the fastest-constructed NFL stadiums ever, says Robert Rayborn, who co-directs the project for Turner/Devcon and oversees a crew of some 1,200 laborers each day.

The stadium will also be the NFL’s most technologically advanced, with more wireless access than any other and huge screens and scoreboards offering higher definition than ever before.

Since well before it first began to appear on that lonely patch of concrete, Berkeley graduates like Kim have played a major role in the project.

It started with Seattle-based structural engineering firm Magnusson Klemencic Associates (MKA), a company stacked with Berkeley talent. Among its 110 structural engineers, 18 have master’s degrees from the college. Among senior staff, 40 percent are Berkeley alumni.

Senior Principal Jon Magnusson (M.S.’76 CE) said MKA completed design work for the stadium under extremely tight deadlines, following decisions to move the stadium from San Francisco to Santa Clara and to open one year sooner than originally planned. Still, the company was able to deliver 66 superstructure options to the 49ers, who ultimately selected a design featuring 16,500 tons of steel plus precast structural seating and stairs. This would have been a tough act to follow, until four cranes swinging in sync assembled the superstructure in record time. “It was just an unbelievable pace,” says Magnusson.

A key member of the MKA design team was senior principal and director of earthquake engineering John Hooper (M.S.’84 CE). The stadium sits on deep, soft soil, not far from the San Andreas Fault; Hooper was in charge of making it seismically safe.

“On a scale of one to ten, with ten being most challenging, this is an eight or nine,” he says. “A ten would be if we were sitting right on top of the fault, like Memorial Stadium at Cal. Most of what I do is an eight or nine.”

Hooper’s solution was to integrate a system of buckling-restrained braces (BRBs) into the steel superstructure — thin steel rods surrounded by concrete mortar within a steel tube. “Picture a paper clip at your desk, then bend it back and forth,” he says. “You might be able to bend it four or five times before it snaps. A BRB you can bend 50 or 60 times before it snaps, and an earthquake wouldn’t cause it to bend that many times. They are the fuse that takes all that energy and dissipates it so that the rest of the building doesn’t have to.”

Among the design and engineering features of the stadium are these buckling-restrained braces (BRBs) for earthquake safety. (Photo courtesy Turner/Devcon)

He also set the stadium atop some 3,000 pilings up to 60 feet deep that anchor the structure into solid ground below. The system is designed to prevent casualties in the event of a “maximum design earthquake,” a 95-percentile quake induced by the San Andreas — something that occurs approximately once every 2,500 years.

Jennifer Diggs (M.S.’11 CEE), who joined MKA shortly after graduating, helped prepare the final drawings. Normally she works in the company’s hotel and housing concrete department, but a well-balanced course load at Berkeley helped prepare her for the task. “I took all the structural classes I could,” she says, “nonlinear, steel design, materials, pre-stressed concrete.”

The elaborate superstructure will eventually be hidden from view, in part thanks to another Berkeley graduate. As curtain-wall and façade consultant for
the stadium, David Von Volkinburg (B.S.’74, M.Eng.’79 CE) is responsible for much of what the public will see when the stadium is unveiled for the 49ers’ 2014–15 season next August. A massive glass entrance will reveal to visitors the artfully lit, crisscrossing escalators within.

“We basically determined how to build the exterior skin of the building,” he says. It was a bit more complex than this sounds, incorporating not only aesthetics, but also waterproofing, construction of the building envelope and accounting for how the building will respond to earthquakes and wind.

He’s done it many times before, including for the new Eagles stadium in Philadelphia, the Staples Center in Los Angeles and city halls in Oakland and San Francisco. Architecture and engineering are required for this cross-disciplinary work—skills Von Volkinburg picked up at Berkeley as an undergraduate and later as a graduate student in engineering. “I just learned how to have an open mind,” he says. “It’s paid off for me over the years to think outside the box.”

In between the waterproof skin and the quake-proof superstructure is the space that most interests Kim. As MEP manager, he oversees several complex systems that snake their way throughout the stadium: mechanical, electrical, fire protection, plumbing, telecommunications, audio/visual, security, scoreboards, food service, HVAC and more. Kim also serves as LEED coordinator, responsible for making sure the stadium achieves its unprecedented Gold rating.

In addition to the living roof and solar panels, the stadium’s green features include low-VOC-emitting paints, coatings, adhesives and sealants; high-efficiency plumbing fixtures; bioswales integrated into the landscaping to help capture runoff; and reclaimed water for irrigation and sewage conveyance.

“From a social consciousness perspective, I just think it’s the right thing to do,” says 49ers project executive Jack Hill, who previously managed the Dallas Cowboys’ stadium. But it’s also part of representing the 49ers’ home to the league and to fans around the world. “If you look at the personality of the Bay Area,” Hill adds, “I think the stadium fits into that mold.”

Throughout a two-hour, three-mile tour of the half-complete building, Kim begins to imagine all the pieces coming together. Sixty-seven-thousand ticket-holders (up to 75,000 for the Super Bowl) marvel at the glass-walled tower as they approach. Once inside, spectators are treated to HD scoreboards, seamless Wi-Fi access and low-flow, sensor-controlled plumbing (even if they have no idea about the BRBs). During pre-game and commercial-break flyovers, television viewers enjoy sweeping perspectives of an expansive green roof and a network of solar panels.

Meanwhile, Jon Magnusson, John Hooper, Jennifer Diggs, David Von Volkinburg, Kesor Kim and the thousands of others who have contributed days, weeks, months or years to the inner workings of the stadium will see something else, something even more complex. And they might have the sweetest vantage point of all.