Metrodome Roof Collapses?

[grizz441]

Based on latest code it probably should have been designed, assuming a cold roof, for 24psf flat snow load, 5psf rain on snow, round it up to 30psf...(not sure about the code 30 years ago)

30psf load with 20.5pcf density

30/20.5 = 1.46ft = 17.6 inches snow design.  Assuming no unbalanced snow, (and proper drainage) which I don't know enough about a dome structure to know if you can make that assumption.  So hell, after all safety factors, are taken into account from both snow loads and fabric loads I would think it would be able to take at least 40psf of load before failing, which would be 2 feet of snow.  Not enough info though.

[Masherbrum]

Based on latest code it probably should have been designed, assuming a cold roof, for 24psf flat snow load, 5psf rain on snow, round it up to 30psf...(not sure about the code 30 years ago)

30psf load with 20.5pcf density

30/20.5 = 1.46ft = 17.6 inches snow design.  Assuming no unbalanced snow, (and proper drainage) which I don't know enough about a dome structure to know if you can make that assumption.  So hell, after all safety factors, are taken into account from both snow loads and fabric loads I would think it would be able to take at least 40psf of load before failing, which would be 2 feet of snow.  Not enough info though.

As heavy of a snowfall as this was, it wouldn't have mattered.   This snowstorm that hit us the day was as wet as can be.   Domes have no place up here, down South or out West in the warmer climates, absolutely. 

[SunBat]

I'm thinking since it was engineered to meet the requirements specificied and detailed by the paying owner or his design team, it's the owner's or designer's fault.  They should of specified a more expencive, durable and reliable alternative as I'm sure the structural engineers designed it to the specifications that they had to.

Wrong.  Any structural engineer that designs to the customer’s specifications and neglects the governing codes will not be an engineer very long.  It is the responsibility of the engineer to protect the public even if that means the customer has to cancel the project because they are not willing to cover the cost.  I don’t know all of the details related to this case so I will withhold my opinion, but I will say that the roof should have been designed according to the local and state building codes which would allow for a snowfall like that roof just experienced.  If the engineer didn’t do that, they are very fortunate nobody was hurt and they deserve the lawsuit that is heading their way.      

SunBat, P.E.  

[grizz441]

As heavy of a snowfall as this was, it wouldn't have mattered.   This snowstorm that hit us the day was as wet as can be.   Domes have no place up here, down South or out West in the warmer climates, absolutely. 

The design snow density for minneapolis is 20.5 pcf.  Water is 62.4 pcf for comparison.

[SunBat]

As heavy of a snowfall as this was, it wouldn't have mattered.   This snowstorm that hit us the day was as wet as can be.   Domes have no place up here, down South or out West in the warmer climates, absolutely. 

I know of domes in Red Dog, Alaska and Sahklin Island, Russia that had way more snow than that and never fell down.  As a matter of fact, I used to work for the company that made those domes.  

[SunBat]

As a matter of fact, here is the last dome I designed at that company before I left.  This is as seen from Google Earth.  It is in New Braunfels, TX.  



Here is one I dug up taken from the ground right after construction of the dome was complete...



EDIT:  She was still on the ground and not permentantly mounted to the wall when Hurricane Ike came through and I had to design a tiedown system to keep her from flying away during the storm.  It was rather nerve racking to say the least. 

[Dichotomy]

I've actually seen that several times

[Shuffler]

Woot... the Hill Country is my playground.

[SunBat]

I've actually seen that several times

Cool. Now u can tell people u have shot the guy down that designed that.

Yeah, Shuffler, that hill country lore is what I fancy, where streams run clear and Lord the skies they are so blue...

[68ZooM]

well when i need calc's done on a home design i'll know where to throw my money  lol

[Tupac]

Woot... the Hill Country is my playground.

Thats over highway 46 at 7,200 feet.


San Antonio


Lake Medina

Hey Sunbat, where in NB is that dome you built? Im sure ive seen it quite a few times, it looks pretty familiar

[Tupac]

Also Sunbat, did you know a guy named Gerhardt Kramer? (I think thats how you spell his name) He builds geodesic domes and was in new braunfels building one.

[Shuffler]

Cool pics Tupac.

Makes me want to drag my 32 footer up there for a little camping and kayaking on the Guadalupe.

[SunBat]

Hey Sunbat, where in NB is that dome you built? Im sure ive seen it quite a few times, it looks pretty familiar

That dome is in Hunter, Texas which is pretty much right in between NB and San Marcos.  You can see it from I-35. 

That name sounds familiar, he may have been one of the construction hands that we hired on contract to work on that job.  Can't remember for sure.   

[MarineUS]

if only the game had been going on - tons of snow. weeeeee

its mother nature's way of saying "You can't hide from me. Play like real men!"