Ever since the Metrodome was completed in 1982 it has been seen as a mistake by many people in Minnesota. Considered a marvel of engineering in the early 1980′s the Metrodome held promise as a great example of an air-supported fabric roof stadium, viewed as a simple, economical way to cover large spans. That vision for fabric roofs was never realized as the Metrodome was plagued by problems in the design and engineering from the beginning. Just 48 days after an elaborate ceremony marking the inflation of the Metrodome, the first heavy snow of the winter season arrived and the Dome went down.
The stadium’s roof, after partially collapsing the day before, completely deflated under the weight of 10.2 inches of heavy, wet snow. Stadium authorities blamed the deflation on a large rip in the roof, caused by a puncture in the panel of the fabric on the north side of the stadium. There were no injuries, and the roof was repaired and reinflated four days later, before the next snow could have done more serious damage. The rip was caused when a bolt snapped, bending a piece of steel which slashed through the fabric roof. The roof is kept in place by air pressure from up to 20 fans inside the stadium, and the dome collapsed when air escaped through the hole. News of the deflation, along with the heaviest Twin Cities snowfall since Nov. 17, 1978, was carried on all three network evening news shows and was featured at halftime and before games the following Sunday and Monday on various National Football League telecasts.
Now, almost thirty years after the Metrodome was constructed, heavy snowfall hit Minneapolis again and once again the roof of the structure ripped and deflated. Originally there were three tears that happened on Sunday morning, but Wednesday, a fourth rip appeared in the roof. Now is a good time to ask questions about the Metrodome and the fabric roof. Is an economical, experimental structure, such as the air supported fabric roof of the Metrodome appropriate or safe for a major facility in Minneapolis?
Construction on the Metrodome started in 1979 in Downtown Minneapolis. Chicago architects and engineers Skidmore, Owings and Merrill (SOM) teamed up with Minneapolis based Setter, Leach Lindstrom to design the Metrodome. The designers for the air-inflated fabric roof were New York based George Berger Associates. An Engineering News Record Story from 1981 describes the stadium’s structure and roof. This passage describes how the roof designers planned on dealing with snow:
“The 9 1/2 acres of fabric, manufactured and installed by Birdair Structures, Inc., Buffalo, N.Y., is actually two layers, the largest expanse ever done in this way. The outer layer is Teflon-coated fiberglass and the inner is a proprietary acoustical fabric. The dead air space between the layers insulates the roof, Birdair says, and warm air will be blown between the layers in the winter to melt snow that has accumulated on the roof.”
Another quote from the article talks about how the designers and client were reaching for the ‘moon’ with the design:
“This is a descendant of the Pontiac Silverdome,” says Donald Poss, executive director of the Metropolitan Sports Facilities Commission, owner of the stadium. “But it’s the Apollo moon shot compared to the Mercury space program.”
Many people don’t know this about me, but I am a Registered Architect in the State of Minnesota. I have worked on many large building projects and overseen construction on large projects locally. I have long thought that the Metrodome needs to be shut down in favor of a new stadium. As I wrote earlier, the air-inflated fabric roof of the Metrodome was an untested, economical way to build a stadium 30 years ago. Now roof of the Metrodome is failing miserably. I believe we have a civic responsibility, as a society, to build facilities the public can enjoy safely. Knowing that we basically have the “space program” of stadiums makes this an even more important issue.
There is talk of a new Stadium Bill being introduced at the Minnesota State Legislature in January. Some law makers are in favor of it. Others say they won’t support it in favor of keeping the discussion on “jobs and the economy”. As an architect not currently working in my own industry because Building and Construction has taken such a hit in the current recession (really a depression or more like an evisceration when it comes to the Building and Construction sector), I have to say, a Stadium Bill is about jobs and the economy. In fact, I can’t think of a better stimulus package right now.