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Author Topic: Roof Collapse in Indianapolis  (Read 98469 times)

David Buehler

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Re: Roof Collapse in Indianapolis
« Reply #180 on: August 19, 2011, 03:09:12 am »

The relevant Ernie Mills photo's attached - the circled item appears to be the nylon webbing used at end of guy cables. A look at other photos in the Ernie sequence shows that guy cable attached just in front of the semi trailer to left of stage - there is a single rail metal guardrail there - mounted on large wood posts.  In another photo you can see the nylon webbing was at the attachment end. Its highly likely this nylon web was wrapped around guardrail and/or one of the posts.

Looking closer - from the length of the nylon flying thru air - it would seem most of it is still there - failure might be more likely to have been the loop on one end ... again, really pretty immaterial
Without seeing how installed its hard to tell if the guardrail cut the nylon, but realistically, withe the then entire weight of the collapsing structure on that singe guy it really probably didn't matter - the structure was going down anyway. But just another questionable decision it might seem.

Scott

The highlighted photos prove exactly what i've been saying, that the ballasting element (weight + cabling + hardware) was unable to hold the roof from moving,and once the initial gust was able to slack the guys on the back side or stage right side of the roof (before the big gust), the physics of gravity took over when the grid was able to shift beyod the point of downward force being exerted on the towers (~3' or so). The towers snapping directly below the corner blocks is still puzzling but I wonder if the nylon webbing on the guy wire straps that failed on the guys created a intense shock load that somehow was able to break the welds or bolts, combined/enhanced/multiplied by the falling motion of the grid that causes the breaking.

The stability of the grid is only as as its weakest link; in this case: Holding Strength, compromised by rigidity.

Nylon straps absolutely should not be used in guying applications, there is no way to ensure consistant holding strength. Grip hoists are a much wiser and safer solution plus, far easier to maintain tension during high winds. I dont think they're heavily used due the inhearant cost difference between tirfors ($500+) vs nylon straps ($25) each...
« Last Edit: August 19, 2011, 03:16:09 am by David Buehler »
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David Buehler
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Audio - Video - Staging & Roofs - Crewing - Production Management & Design

ScottAllan

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Re: Roof Collapse in Indianapolis
« Reply #181 on: August 19, 2011, 05:35:22 am »

Scott

The highlighted photos prove exactly what i've been saying, that the ballasting element (weight + cabling + hardware) was unable to hold the roof from moving,and once the initial gust was able to slack the guys on the back side or stage right side of the roof (before the big gust), the physics of gravity took over when the grid was able to shift beyod the point of downward force being exerted on the towers (~3' or so). The towers snapping directly below the corner blocks is still puzzling but I wonder if the nylon webbing on the guy wire straps that failed on the guys created a intense shock load that somehow was able to break the welds or bolts, combined/enhanced/multiplied by the falling motion of the grid that causes the breaking.

The stability of the grid is only as as its weakest link; in this case: Holding Strength, compromised by rigidity.

Nylon straps absolutely should not be used in guying applications, there is no way to ensure consistant holding strength. Grip hoists are a much wiser and safer solution plus, far easier to maintain tension during high winds. I dont think they're heavily used due the inhearant cost difference between tirfors ($500+) vs nylon straps ($25) each...

Yep - I was amazed when I reviewed the chopper footage - at how simple and clear the failure was.

Ballast was pretty clearly not sufficient - when loaded by initial wind gusts the barriers simply slid in on the blacktop and grass they were sitting on ... and with some velocity judging by the damage to the fence where they impacted it.

I strongly doubt there was any staking of the barriers - unlikely they would put steel rods into the parking lot - and if as looks possible, they were on the grass staking would have done little good IMO ...

It seems ridiculous - although I acknowledge hindsight is always 20-20 - that with this stage erected every year in same spot  - and considering the permanent concrete stage itself - that the crucially critical guy points were not similarly permanent. Pour some concrete, install some poles, or any of many other means of creating properly engineered permanent hard points.

There are so many failures in this sad situation it is amazing.

Had any ONE of these failures NOT occurred we very likely would have had a dramatically different outcome: properly installed, secured and sized ballast; proper stage design/assembly/structure (X-bracing, horizontal bracing, the extra outrigger towers, etc); proper guy attach points, and most of all a COMPETENT weather observer onsite and adherence to a proper plan ...

Heck, not even that, had they simply cleared people out when the severe tstorm warning was issued ...

That there was so little attention to such critical details in so many different areas is to me extremely troubling.  I initially felt there should be support for a negligence charge in this. I'm now even more positive of that ... I personally think there is clear negligence, and with thr admissions coming out that they were notified and strongly encouraged to take action and ignored those warnings, I think raises this awfully close to criminal negligence.

At best it is gross incompetence - which directly caused 5 deaths and numerous injuries. And none of it had to happen had these people made simple common sense decisions.

   
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Jeff Bankston

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Re: Roof Collapse in Indianapolis
« Reply #182 on: August 19, 2011, 05:53:48 am »

i was born in mccomb missippi, grew up in jackson missippi. a sunny day would turn dark like the clouds in foto very quickly and the storm would hit. some storms would have very high winds with severe lightining and sometimes hail. i look at the clouds in the foto thinking if i had ben there i would have gone to a permanent building. i watched a tornado pass over our house once from one of those storms. those people should have ben evacuated and the show canceled.
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alan hamilton

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Re: Roof Collapse in Indianapolis
« Reply #183 on: August 19, 2011, 10:03:54 am »

I have word that one of the injured from the Ind State Fair has taken a turn for the worse and is not expected to make it. Let's all hope the death toll doesn't rise but clearly the situation is still bad.
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Jon Waller

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Re: Roof Collapse in Indianapolis
« Reply #184 on: August 19, 2011, 11:11:52 am »

Very insightful analysis and comments by Mr. Allan, Mr. Buehler, and others.

I would like to pose the following questions to everyone following along:

Why are there so many collapses in the last few years?  I don't remember hearing of any years ago.

Some possible answers:

1.  I was just not following events years ago, they were happening then also.

2.  The weather is just worse now.

3.  There are many more events being held with temporary structures, therefore a greater chance that some of them will be struck by severe weather.

4.  Modern stages are not built the way they used to be (out of massive amounts of construction scaffold), as it has become a 'race to the bottom' for the biggest stage at minimum transport and labor cost.

My personal feeling is that it is a combination of 3 and 4.  What do you think?
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Weogo Reed

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Re: Roof Collapse in Indianapolis
« Reply #185 on: August 19, 2011, 01:14:55 pm »

Hi Jon,

" 2.  The weather is just worse now. "

I don't know how much extreme weather was a factor in the Indianapolis stage collapse, but weather extremes are more frequent and severe.

Here's an article on the weather:

 http://green.blogs.nytimes.com/2011/08/17/weather-alerts-are-imperiled-noaa-warns/

We can build better structures, but at some point, the wind will blow and the thing to do is get folks out of harm's way.
By the way, the link above directly speaks to replacing a satellite used to predict severe weather events and give early warnings.
 
Thanks and good health,  Weogo
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Jeff Bankston

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Re: Roof Collapse in Indianapolis
« Reply #186 on: August 19, 2011, 02:27:22 pm »

just on the news, a 6th person 22 year old Jennifer Haskell has socomed to injuries and died.
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James A. Griffin

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Re: Roof Collapse in Indianapolis
« Reply #187 on: August 19, 2011, 02:45:17 pm »

Modern stages are not built the way they used to be (out of massive amounts of construction scaffold), as it has become a 'race to the bottom' for the biggest stage at minimum transport and labor cost.

+1   Our clients keep asking for bigger shows at lower costs.   Our dilema is to lower our own costs without compromising safety.   There is always some risk, it is never Zero.    Our thinking is sometimes "okay, I can save $XXX if I don't do XYZ at the show, and my risk only increases .02 %"   
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Jeff Bankston

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Re: Roof Collapse in Indianapolis
« Reply #188 on: August 19, 2011, 03:19:43 pm »

i was just thinking WHY would people in charge want a band to play on an outdoor stage with a storm coming thourgh ? with wind and rain messing up the sound and getting the pa speakers wet i am at a loss for their thinking. it would seem to me that you would "batton down the hatches" until the storm passed. i dont own flown speakers so i cannot comment as to their resistance to rain but it will damage certain equipment if it gets wet. do bands actually play outside when its raining at these events ? i never went to a fair on a cloudy day. we never played if the weather report had rain in the forecast. what are the people in charge thinking when they make these decisions ? i read on the Yahoo news site yesterday that Sugarland was getting ready to go onstage when their manager told them to get out of there and about 30 seconds later the thing colapsed.
« Last Edit: August 19, 2011, 03:22:16 pm by Jeff Harrell »
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Doug Fowler

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Re: Roof Collapse in Indianapolis
« Reply #189 on: August 19, 2011, 03:40:09 pm »


That's enough speculation.

I will start another thread for followups.
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Re: Roof Collapse in Indianapolis
« Reply #189 on: August 19, 2011, 03:40:09 pm »


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