Structural question about JTS
- Thread starter wartknight
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A lot of the limiting factors in the design of steel beams and columns have to do with limiting sway and displacement. If you're willing to live with more movement you can get away with a much more economical design.
Stadium swaying a few inches when things get rocking = fun
1000' sky scraper swaying a few feet duing a wind storm = not so fun
Stadium swaying a few inches when things get rocking = fun
1000' sky scraper swaying a few feet duing a wind storm = not so fun
I was on the upper deck in the student section for the Iowa game in 2005 and did not notice a lot of shaking... and that was probably the most amped up game I've ever seen on the upper deck. Perhaps we were all too focused on cheering our lungs out? 
I would say something like this is fairly normal. I'm sure the weight limit on those upper decks are enormous.
I would say something like this is fairly normal. I'm sure the weight limit on those upper decks are enormous.
I was in the first row of the upper deck student section for the Iowa game. I couldn't believe how much it was shaking at some points. Normally (being extremely afraid of heights) I'd have been freaking out, but I was too concerned with the game to care. I'd never noticed it do that before, but I've only been in the upper deck for a couple games.
Hyatt Regency - Kansas City 1981. Between the weight and the dancing....boom.
I suggest you sit very still at the Texas game.
Hyatt Regency walkway collapse - Wikipedia, the free encyclopedia
I suggest you sit very still at the Texas game.
Hyatt Regency walkway collapse - Wikipedia, the free encyclopedia
That's why I sit on the lower level...back when I was in school, thought it was fun, now I want terra firma!
I get motion sickness and really noticed it moving. We've sat in the same area for a few years and this year has been the most I've felt it move! (Section N)
Structures can move (and move quite a bit sometimes!) withou being un-sound. I/ We often have conversations with our structural engineers about how much movement or deflection is "tolerable", meaning that it doesnt make people nauseous, or worried. An example in design is that a structural engineer will say: "we have plenty of steel, concrete, whatever... To hold it up, bit inhabitants may notice movement or vibration - is this ok? If not, we will need to add structure, and that will increase cost. So the controlling factor might be the expectation that movement is not noticeable... It's up to you"
I write this as I sit at my desk and feel the floor of my office shake. It's safe, but te deflection is noticeable. The moral is, ALL buildings move, most just aren't noticeable.
Another example is Valley West Mall - the upper level will vibrate noticeably at times.
I write this as I sit at my desk and feel the floor of my office shake. It's safe, but te deflection is noticeable. The moral is, ALL buildings move, most just aren't noticeable.
Another example is Valley West Mall - the upper level will vibrate noticeably at times.
Yes they did!
[ame=http://www.youtube.com/watch?v=I4C9SHNzysw&feature=player_detailpage]Iowa State: Knapp & Storms Hall Implosion - YouTube[/ame]
That's why I sit on the lower level...back when I was in school, thought it was fun, now I want terra firma!
Yes, but are you within falling distance of the upper deck?
I sit in the upper deck. I'm hoping for lots of big ol' bodies (corpses) to break my fall.
Upper deck as well. I have just always assumed if the upper deck fell we would just slide on down from the guts of the lower level people and become the new lower level. It would be so smooth and a nice soft landing they may not even stop the game.
It did the same thing when Luther Blue ran a kick-off back against NU in 1976 (7?)[/QUOTE]
until this years Iowa game, best home game ever. (1976, freshman year (sigh))
until this years Iowa game, best home game ever. (1976, freshman year (sigh))
As a Licensed structural engineer in Iowa, and currently working for a firm that does structural design of stadiums, you're probably ok. I've designed a few seating bowls including cantilevered seating bowls, what you're experiencing is the vibration due coordinated or semi coordinated up and down crowd movements. when you are sitting front row at the end of the cantilever you are feeling this upward and downward acceleration (% of gravity), think of the end of a diving board (not quite that pronounced), or a board spanning a couple joists with one end free. Now a days stadiums are designed specifically for these conditions, they were back then too. We just know more about structural vibration responses now. I am sure the university's building operations are aware of it, but it wouldn't hurt to send an email to the athletic department. Sounds like it is only noticable at or near full capacity. Here is a great story even mentions ISU. College - Prerecorded Music Gets Fans Moving During Games
As I recall, when JTS was built, the East side sank and had to be fixed before it was opened...Had to do with having been built on a flood plain as I recall. the history of the problems in building JTS is out there. It was started in 1973 , finished in 2 yrs, opened in 1975. I recall more than one problem with shifting when built.
Now, doesn't that make you feel even more safe, knowing that?
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