Commissioned Report on Indiana Fair Tragedy

Re: Commissioned Report on Indiana Fair Tragedy

Milt Hathaway said:
Yeah, that's what I said. :D~:-D~:grin:

I'm just tired of hearing "If it gets too bad we can bring in the roof." and "Why didn't they bring in the roof?"
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In another shortened version I read (it was linked by Steve Hurt, I believe) this was described as the "contingency plan" of the owners/users and the comission deemed this inadequate due to not being practically feasible. In other words, what you said.
 
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Re: Commissioned Report on Indiana Fair Tragedy

David Sturzenbecher said:
Didn't it mention that this roof had the weight removed from the chain motors by applying a strap over the head block? That would most certainly increase the time to lower the roof, having to climb each tower and release the weight. Then can the motors support the weight of the added sound, lighting, video equipment that has been added since the straps were in place. I have worked with smaller roofs before, but none that had this procedure of taking the weight from the motors in place. Is this common practice with all roofs?
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David,

In this case it is immaterial. You would not be able to lower the roof, even if it was directly tied to the motors, because doing so would remove the lateral support the structure needs for stability. This is the crux of the matter.
 
Re: Commissioned Report on Indiana Fair Tragedy

I'm still working through the report, but the issues I noted were ones of failing to follow the flawed, but more stringent 2010 Thomas report, and that the guying implementation from 2010 was pretty much NOT what was done in 2011. It appears that the choice of wire rope diameter was made on site by whomever erected the roof.

I looked at the reports on the "fin plates" and saw that TT noted those plates would be unable to sustain the applied load. This is a fundamental design issue for Thomas.

How it sorts out, and what other engineering firms that will testify as expert witnesses have to say about it all, will be illuminating.
 
Re: Commissioned Report on Indiana Fair Tragedy

One of the other things I noticed on the Thomas literature that was included was the recomendation to check the welds for cracks using dye or a magnifying glass, but to me that's a skilled job not something an untrained person should be signing off on. I've never seen these structures up close during assembly so sorry about the roof coming in comment, is there a version of these where guying it is not such a critical thing ie is there a way of making the thing self supporting to a greater degree if not completely so? One other question are these guy attachment points only able to be put on the corners or can they be put in the middle of a frame member so that the load could be shared out and reduce the total load per point?
G
 
Re: Commissioned Report on Indiana Fair Tragedy

gordon mcgregor said:
One of the other things I noticed on the Thomas literature that was included was the recomendation to check the welds for cracks using dye or a magnifying glass, but to me that's a skilled job not something an untrained person should be signing off on.
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Dye penetrant tests have their own ASTM standards, and you're right that they are not for an untrained person. Ideally you'd want at Level II or Level III certified NDT tech:
http://www.asnt.org/shop/merchant.ihtml?pid=1633&lastcatid=11&step=4

I've never seen these structures up close during assembly so sorry about the roof coming in comment, is there a version of these where guying it is not such a critical thing ie is there a way of making the thing self supporting to a greater degree if not completely so? One other question are these guy attachment points only able to be put on the corners or can they be put in the middle of a frame member so that the load could be shared out and reduce the total load per point?
G
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Self supporting would be very difficult based on designs composed of truss sticks. They are carefully built to transmit only dead load, and not lateral loads or bending moments to the support truss legs. There's nothing inherently wrong with guyed systems, indeed its often the most expedient engineering method.

I can't speculate on where additional guying could be placed to distribute the loads, but it should be possible to distribute it better.
 
Re: Commissioned Report on Indiana Fair Tragedy

Question for those more knowledgeable than I.

If the guy wires were attached to something permanent (and that "something" did not fail in the storm), do you think the structure would have come down?
 
Re: Commissioned Report on Indiana Fair Tragedy

Steve Hurt said:
Question for those more knowledgeable than I.

If the guy wires were attached to something permanent (and that "something" did not fail in the storm), do you think the structure would have come down?
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The report engineering shows that it would have failed regardless of the type of anchor and at wind speeds lower than either the applied standard or speeds calculated by Thomas for the 2010 design. There are several potential points of failure, but the primary one is that the "fin" plates could not sustain the total load of self weight, production equipment, and *designed* wind load. Lots of components failed in different ways and at different points in the collapse (there are hundreds of pictures in the report), many did not, and some inadequate practices appear to have been used in erection of the structure.

You should read the 110 pages of the report. You can skip the appendices for the time being... but that's where the pictures are.
 
Re: Commissioned Report on Indiana Fair Tragedy

Steve Hurt said:
Question for those more knowledgeable than I.

If the guy wires were attached to something permanent (and that "something" did not fail in the storm), do you think the structure would have come down?
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Fixing the weakest link in the chain just makes the next weakest link shop up.
I think the issue here is that many aspects of the design/implementation were done without sufficient safety margins built-in.
if the guy wires were attached to something stronger (at both ends) and if they were thicker, and if the truss was loaded properly (or stronger to take the additional load) and if, if, if, then it would be fine..
it's all about balance. you have to either design the structure for the intended load, or only load the structure according to its design. a hybrid of both is always a bad idea.

Jason
 
Re: Commissioned Report on Indiana Fair Tragedy

Jason Lavoie said:
Fixing the weakest link in the chain just makes the next weakest link shop up.
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Though of course fixing the weakest links is the top priority in remedying any deficient situation. As you point out, if the next weakest link is still too weak, you're not done yet, but you're better off than you were before.
 
Re: Commissioned Report on Indiana Fair Tragedy

Phil, by self-supporting I had in mind this sort of thing Orbit Stage - Serious Stages this one is one I've been on and actually helped put part of the cover on not fun in freezing temps. I've never seen guying involved with these stages though there is some ropework involved in the cover, these have their limits as well re wind, weight etc and no doubt some muppet will find out the hard way what happens if you ignore the limits. Flexible rigging ie guy ropes etc is something I know a fair bit about due to restoring old aircraft, over the years I've learnt that it is very easy to put a brace wire in the wrong place or even simply get the angle and tension wrong and they can be next to useless even though it all looks fine ( not fun watching a wheel disappear up a runway because someone didn't tension a wire right) which is what makes me ask about alternatives G
 
Re: Commissioned Report on Indiana Fair Tragedy

gordon mcgregor said:
Phil, by self-supporting I had in mind this sort of thing Orbit Stage - Serious Stages this one is one I've been on and actually helped put part of the cover on not fun in freezing temps. I've never seen guying involved with these stages though there is some ropework involved in the cover, these have their limits as well re wind, weight etc and no doubt some muppet will find out the hard way what happens if you ignore the limits. Flexible rigging ie guy ropes etc is something I know a fair bit about due to restoring old aircraft, over the years I've learnt that it is very easy to put a brace wire in the wrong place or even simply get the angle and tension wrong and they can be next to useless even though it all looks fine ( not fun watching a wheel disappear up a runway because someone didn't tension a wire right) which is what makes me ask about alternatives G
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Gordon,

I'm all for the kind of stage in your link, though you'd need a Glastonberry-sized one to match the scale of the failed structure in question here. I'm also for pre-simulated, and pre approved, rigging configurations. I think these stage issues also bode well for Stageline-type stages going forward here in the states, though obviously not for roofs of the scale of the one here.

-Phil
 
Re: Commissioned Report on Indiana Fair Tragedy

I've seen similar stage systems with a 30m front width, the main Glastonbury stages are largely similar only bigger and not uncommon in Europe. I think this is a result of the strict rules for temporary structures we have here, also the stages come as a complete system which is easily checked by the local inspector, ie if it doesn't look like the picture start asking questions. I agree those who own Stagelines etc should be able to make hay this year

hoping that something good comes from all this G
 
Re: Commissioned Report on Indiana Fair Tragedy

Having spent the past few days on the road and having a lot of time for reading while travelling, I had a very good long look at the detailed all inclusive report. The findings are all very very sound, and indeed, corners were cut in the construction of that stage (budgetary, oversight, whatever one may attribute to the reasonings. Shall leave that for the courts to decipher). Not necessarily in the design (however, the fin plates have me very curious. Looking at the metallurgical reports, and at others mention of them being a weak point I do concur. As a welder, I see a pile of welds that were improperly done. Little to no base metal amagalmation where the parts meet, relying strictly on a single or double root pass weld to carry the load. That kind of stuff scares me.), but in the assembly of the design. There will be a lot of good things come out of this I hope, with increased regulation and calls for proper engineering documentation with every temporary structure that is erected.

Gordon is on the money.......companies such as Stageline and MSR will have a pretty good couple years ahead of them I feel. I always feel better on an SL260, 320 or SAM than some of the scaff decks out there.
 
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