LPL's next forensic challenge

Well, The Roof Fell In, Of Course

The Metrodome was opened in 1982. It had collapsed in 1981 and 1982, most probably due to leaks or unfollowed protocols. In 1983 heavy snow deflated it requiring 4 days of repairs. In 2010 it was now 28 years old with the original fibreglass fabric. It is actually 2 layers, inner and outer with both secured to the cables. The whole building is inflated to dome it up. Between the 2 layers the extra inflation is to keep the fabic taut and reduce wind whip. With the fabric age, heavy snow and heavy winds I would say it was over stressed. The interior was being heated to 95° to expedite the snow melting and flowing off the roof. Men had also been on the roof shoveling off snow. A lot of things could have caused a minor tear or fabric weakening. Thankfully no men were on the roof when the first tear let snow in and the air pressure out. Once it became saucer shaped the snow accumulated faster and concentrated weight at the panel centers. That led to the later tears.

Repair crews are coming tomorrow but in my opinion it is not economical to patch a worn out fabric. Before any patching takes place they need to first get all the snow off.

The Vikings have only one more home game on 12/20 and no playoffs in sight. They should play that last game at the new University of Minnesota stadium. Two weeks should be plenty of time to clear the snow off that field. Then they should plan on a new fabric covering for next season or leave town a year early. Possibly this will get the Vikings some sympathy from the tapped out state legislature and all the unemployed state taxpapers to push their request for a new stadium off center. After all the Minnesota Twins and the University of Minnesota Golden Gophers already have their new stadiums.

The Carrier Dome at Syracuse University was built in 1980. Prior to snow storms the layer between the Carrier Dome roofs is filled with 160° air. The roof fabric was replaced in 1999. That might be the difference. I have not compared Minneapolis Winters with Syracuse Winters but I would think Minneapolis wins. If the Carrier Dome were just a few miles North of Syracuse in the lake effect snow area, that would give the nod to New York.

Paul in PA

Well, The Roof Fell In, Of Course

so it looks like it needs more hot air... and I appreciate your expertise on hot air. 😉

It seems like it would be natural for some type of solar application to keep it thawed in the winter months.
I am glad that the Twins finally moved out of the "Baggie". To me it was the worst venue in the MLB.

They should probably end up the season playing in the dome in San Antonio.
Refund all ticket holders and write it off and let their business insurance pay.

As I was reading the articles about the roof deflating then I saw one comment that made me smile.

"At least for one night the people in Detroit will have an exciting game to go watch."

Ouch!

Solar Panels Would Not Work

First, they would add weight to an essentially weightless roof.

Second, 60-70% of snow falls at night.

Third, there is very little sun in a daytime snow storm.

Fourth, you would have to keep the snow off the solar panels.

Fifth, you could not get enough energy to melt that much snow even if 2, 3 & 4 were not factors.

Solar barely can keep a well insulated compact dwelling warm under Minnesota conditions and the Metrodome is neither well insulated nor compact. Remember that heat rises and the only thing on that roof is two layers of fabric separated by warm air, for it cannot stay hot very long.

Paul in PA

The Roof Was Designed For A Twenty Year Life.

Syracuse replaced their roof when it was 19 years old at a cost of $14 million.

Minnesota passed on reroofing because the $15-19 Million was too expensive. The expense of losing 2 regular season games is over $10 million in ticket sales, plus parking, concessions and sales tax to the state. Sounds like they would be well ahead financially had they replaced it, because it has to be replaced now, no matter what. That or the Vikings play without a roof next season.

The design engineers say that age was not a factor, old or new it would have failed under the loads this past weekend.

For about $100,000 plus labor they could do a temporary single layer roof of 5 laminated plys (crosswise, lengthwise, 45° right, 45° left and crosswise) of fibreglass reinforced industrial "Visqueen". Two foot wide overlapping seams, and 3 rows of double stick super duct tap at each seam. Lifetime would be in months not years.

Paul in PA

Carrier Dome

A major snowstorm hit Central New York earlier this month, dumping up to between 3 and 4 feet of snow on Syracuse (and the Carrier Dome) over the course of four days.

Preparations to avoid sagging or a tear in the roof (and a possible collapse) start before the snow begins. Air heated to 140 degrees in pumped into the space between the Dome roof’s two layers a day ahead of any storm.

The goal is to get about 85-degree temperature in the space near the center of the roof (since hot air rises, the peak is the warmest spot). The heat transfers to the outside surface of the roof, preventing a base of snow from building up, thereby depriving the falling snow of a place to stick.

The Dome staff constantly monitors the roof with three exterior cameras located on the roof and two more cameras inside the Dome. The video alerts the staff of any deflection or drop in the roof. If the roof sags even a little, it’s a sign that too much snow is beginning to collect.

If the heating system starts to lose ground to the falling snow, the staff will go on top of the Dome and use fire hoses to spray 120-degree water to wash the collecting snow off the roof. Other members of the crew armed with shovels and brooms take up stations around the Dome’s ring beam and keep them clear of snow and water.

So far, in the middle of the Lake Effect Snowbelt, the system has worked. Syracuse averages about 116 inches of snow each winter, 4th snowiest city in the USA.

Marquette MI, has the Superior Dome, a wooden supported domed stadium, but it is much smaller than the Carrier Dome..

The Metrodome Staff Gave Up

They were on the roof with firehoses Saturday night. When the supervisor slipped he declared it a night because they could not keep ahead of the snow and the hot water was freezing on the roof. That essentially doomed the roof.

I believe it is feasible to have six remote controlled snorkel nozzles fully cover the roof area. No need to maintain a continuous human presence.

I do not know if the were using a streaming or a fog nozzle, but the fog nozzle is how snow making machines work. There consultant had told them to fix the many leaks in the roof, perhaps they did not do that. Overall the State of Minnesota has a very poor record on adequate maintenance of anything. The Vikings only lease the dome, I believe the governemnt maintains it. Improper maintenance was what doomed the I-35W bridge.

Paul in PA

Carrier Dome

Sorry, but football should NOT be played indoors. Snow/ice/rain/hot/cold is all part of the game. It'll be a cold day in hell when Pittsburgh gets an enclosed stadium.

But then again, they way things are going, we are all becoming way too soft.

I am going to the Steelers-Jets game this Sunday, whether it rains, snows, whatever. My daughter is coming to visit from Mexico with her boyfriend, we are all going to the game. He is probably going to get a surprise...

We did have a really cool arena for basketball, hockey, concerts, etc that has a retractable roof. Still standing (new Consol Arena), but they are arguing over what to do with it. The roof hasn't opened in a long time, but I was there at a few rock concerts in my younger days when it did open. Sudden Death was filmed there, and there are shots in the recent movie She's Out Of My League.

http://en.wikipedia.org/wiki/Civic_Arena_(Pittsburgh)

Now that is a REAL roof!