deflections for a canterlever stadium roof

[rj47]

I am currently attempting to design a stadium roof that must span a minimum of 30m without columns I was just wondering if anyone knows what the acceptable deflection is for the tip and if there are any codes surrounding this. Also is there any ways to reduce the uplift force as this is the most significant in the design

Any help would be much appreciated

 

[KootK]

Cool. That's one heck of a cantilever. For something like this, I'd not pay any attention to typical code recommendations. You'll want to rigorously look into serviceability in it's purest sense: what really matters. To that end:

1) Make sure that there won't be so much movement that occupants will fear for their lives.
2) Make sure that deflection won't compromise drainage.
3) Make sure that you don't get excessive dynamic flutter.
4) Make sure that you don't get fatigue problems.

It's a tough assignment to be sure.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[dhengr]

Rj47:
A 30m canti., can you make that heavy enough to keep it from just blowing over backwards, and still design a canti. that works? It does have to be heavy enough, stiff enough, to control some of the flutter and vibration from wind and uplift loads. I understand you don’t want columns in sight lines, but this probably can’t be (certainly won’t be) a simple canti. As KootK suggests, the exact magnitude of the tip deflection is not so important, but the movement can’t be fast (fluttery) or particularly perceptible by the attending public, or it’ll scare the hell out of them. I think this probably calls for some sort of a cable stayed roof system from above. The first reaction point for the canti., the large upward reaction point, becomes a high pylon for the cable system high point; and the second canti. reaction point, the canti. hold down reaction point becomes the hold down for the cable system. Then there are some minor variations on that scheme. What other stadiums have you seen and studied, and what are the canti. lengths of their roofs over the stands?

 

[jayrod12]

It's likely too late, but check out Investor's group field in Winnipeg for an idea to get the column free area over the stands. There's a massive arch truss that the canopy hangs from, super cool.

 

[KootK]

How did I not know of this? Awesomeness^3.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jayrod12]

I know right?

What disappoints me is the laypeople that don't understand how fricken amazing it is from a structural perspective.

 

[KootK]

Feather in the cap for Walter P. Moore. Damn Yankees stealing our cool work... We'll just see about that now that the loonie's worthless.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jayrod12]

There was a significant portion of the design work for the roof done by a local firm. Plus all of the seating and foundation work. Hint: I may know the wonderful engineer that completed it all.

 

[KootK]

Well, that's just enough tantalizing detail to ensure a morning of unproductive googling. I should have your SIN and mother's maiden name by noon.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[jayrod12]

It wasn't me unfortunately, but it was someone I can see from my desk with a little neck craning.

 

[Sawbux]

Similar to Seattle Seahawks stadium (Century Link), except for the wavy roof!

 

[rj47]

Thanks for all the suggestions but I've ended up spanning the whole width 80m due to the large horizontal forces that the canterlever cable stay roof design gave me but thanks for all the suggestions