It's only happened twice in 56 years. The first time? Last year.

The Los Angeles Rams will become the second team ever to compete in the Super Bowl in its home stadium when they take on the Cincinnati Bengals in Super Bowl LVI on Sunday. Last season, the Tampa Bay Buccaneers played at home when they defeated the Kansas City Chiefs 31-9.

Construction of the $5.5 billion SoFi Stadium began in November 2016, and the venue, the most expensive ever built, officially opened its doors in September 2020. The Rams share it with the Los Angeles Chargers, another NFL franchise.

A joint venture from Turner and AECOM Hunt, the stadium boasts 70,240 seats — which can be expanded to 100,240 for major events like Sunday's game — 260 executive suites and a unique design to protect from potential seismic activity. Additionally, the 2.2 million-pound Infinity Screen by Samsung video board is suspended from the roof over the field. 

Turner also constructed Paul Brown Stadium, the Bengals home, in a joint venture with Barton Malow. That stadium opened in August 2000.

Here, Construction Dive speaks to California-based Rich Bach, senior leader on SoFi Stadium construction for Turner, to learn more about the site of the NFL's big game.

CONSTRUCTION DIVE: What makes SoFi Stadium so unique?

RICK BACH: Well, its size, of course. It's the largest NFL stadium ever built under a single roof. It's also a very unique structure, being that the seating bowl is a separate structure from the actual roof. The field is also approximately 100 feet down from grade around the site, which is also extremely unusual. So, for example, if you walk from grade, you're on level six so, you look down at the field. 

And that bowl sits inside of a very large excavation, that's got a retaining wall around it. Outside of that is where the support for the roof structure resides. And all of that is for seismic isolation. So it was a challenging project to build because of that structural configuration.

How challenging is it to build a large structure where earthquakes are a concern?

It's pretty large, because there is a fault line not far from the site. So that potential lateral motion was a big driver in structural design. And the other thing is because it was under the flight path for LAX, that limited our height. Hence the reason why this stadium is sunk down in the ground.

In addition to the Super Bowl, SoFi will host the College Football Championship in 2023, and the opening and closing ceremonies for the Summer Olympics in 2028. How much is that need for flexibility on your mind when you're building the stadium?

I think first and foremost, [Rams Owner] Stan Kroenke's vision was to build a world class NFL stadium for the NFL; for the Rams, obviously, and of course the Chargers. So it is a football stadium, state of the art, best in class. 

But it's also part of a larger development. Within the stadium, there is the YouTube theater, which is a 5,000-square-foot venue for smaller concerts. And then the surrounding Lake Park District was designed with these large future large events in mind. Football first, but suited for the Super Bowl and the opening and closing ceremonies of the Olympics.

SoFi claims to have the best fan experience in the league. What does that entail? 

It's fully electronic. So getting in and getting out is easy. You don't have to wait in queues for hours to get in. It's completely cashless and app driven. So, you don't need to bring anything but your cell phone. And they've got a state-of-the-art Wi-Fi system that can handle pretty much everybody, posting live videos and things of that nature. 

Then you add to that the two-sided elliptical scoreboard had never been built before. It's the largest of its kind. It's hard to keep your eyes on the field when you have this amazing thing right in front of you. And then the sheer sound inside the stadium; it's intoxicating. I don't think there's a bad seat in the house, no matter where you sit at the stadium, you feel like it's something special.

Does that pose more challenges? Delivering all of those amenities?

Yeah, it does. The biggest challenge is that you start planning, you start construction years away from when it's supposed to be open, but the technology on the customer experience side evolves, and the programming evolves as you get closer to opening. But we were prepared for that.

The stadium was a joint venture project between Turner and AECOM Hunt. How important is collaboration on a project of this size? 

Collaboration is everything. There was a courtship and honeymoon period between the two firms to make sure that our values were aligned. And our approach to building a project of this magnitude was aligned before we said, 'Yeah, this is good for us.' You know who worked for who when we're out there, but that way it was, it was a singular team.

Were there challenges with the two joint ventures?

There are. Both firms have their very distinct, hundred-year-old cultures. But we learned to adapt to each other and learn from each other. And as I said, once we got going, we were one team. The most common denominator is we all had passion for something and a passion to take care of our client. 

The stadium's construction finished during the COVID-19 pandemic. Was it a race to the finish line before the regular season? 

Look, every project, no matter how much time you have, it's always a race to the finish. So in that sense, we were not unique. But even with COVID, we were able to hold our key dates. It wasn't for the NFL season, actually. It was for some concerts that were scheduled for the summer of 2020 that eventually got canceled, but had they still performed, we would've been ready, for sure.

Was it frustrating to see the games in L.A. played to an empty stadium in its inaugural season? How does that compare to seeing it in full use today?

Of course it was. It was a big letdown for everybody. We were all looking forward to seeing that first game of fans in the stadium, and it was a night and day difference. I went to that first game to an empty stadium and it was anti-climatic, really. Conversely with my first game with people there, it was a completely different experience. The whole stadium came alive.

Who are you rooting for on Sunday?

Well, of course the Rams.