Talk:Indiana State Fair stage collapse

Question about the stage erection contractor
Who is the contractor that erected the superstructure supporting the fly sytem and the roof? I have not seen any press coverage indicating the presence of any triangulation bracing, It is clear that there was considerable weight at least fifty feet above the stage--and while the few supporting legs may have been adequate for a the static downward loads, the failure clearly indicates that they were inadequate to the lateral loads of high winds.72.198.101.30 (talk) 19:29, 16 August 2011 (UTC)

A reference to Wiki's "Fly system" might be appropriate: Fly system   overhead rigging for theatrical events    Homebuilding (talk) 14:16, 17 August 2011 (UTC)

Gustnado.
One article in Scientific American suggests that the stage collapse may have resulted from a Gustnado. This may deserve mention in the article. Opinions? TornadoLGS (talk) 23:41, 16 August 2011 (UTC)

Construction details
The description "fly system" really does not apply here. Most fly sysyems are indoors and permanent and serve the purpose of hanging and moving intended items including lighting and set pieces. The "stage collapse" description in most news reports concerning this accident is incorrect and misleading. The stage per se suffered no failure or played any substantial role in the accident. What did collapse is more correctly call a "portable (or temporary) load bearing roof structure". There are 2 basic designs which serve this purpose in the US. This Indiana accident design is called a "ground support roof". The other main design might best be called a "rigid tower, floating roof" design. It is not bought off the shelf and is only avaliable as a custom designed/manufactured system, allows triangulation of the towers. The second design has been in use for over 30 years, has a good safety, record, is much less common, and is more roof operator dependent in that roof is normally capable of being lovered/re-angled in poor approaching weather if prudent. The ground support's major design concept is that the support towers are held in place by the horizontal roof structure. There is little rigidity supplied by any structure or anchoring at the bases. This design is the most common and in use for just over 20 years, and it the past few years the tower bases have recieved more attention to prevent uplift and/or overturning. The main restraint for stability and resistanace to wind loads has been a system of guy wires. Quite often in past years the guy wire systems on this style roof has been a compromise and somewhat haphazard. Guy wires are preferred because structure triangulation would increase equipment needed, labor, it' s less flexible, and would greatly slow down any needed roof lowering operations. There have been numerous documented cases in years past of this style roof structure collapsing in severe weather. Anyone who is responsible for safe operation and does not plan for servere weather has about as much justification as a boat captain for getting hit with a big wave in poor weather.

In most Indiana accident videos it can be seen as the wind suddenly increases, the downwind side of the blue roof tarp seperates in the center and blows free. The vinyls on this size roof are often multi piece to facilitate their fabrication, to ease installation at the show site, and maybe to allow as "relief/fuse" in a center vent from very high winds that could result in significant uplift. However little thought nor control is given to were that vinyl lands once it breaks free, and most videos show the initial collapse beginning once the loose piece of fast moving vinyl weighing hundreds of pounds catches on the middle upper stage left roof tower and adds unexpectedly much greater wind drag. Of course this is all presently speculation and the in depth engineering study currently underway will likely spell out the actual failure time line.

This roof structure since it depends heavily on it's guy wires/design for support, and in order to lower the roof structure ( the roof is raised by numerous, left in place, industry standard chain hoists) the guys need to be loosened, or become loose as roof is being lowered. So in an appraoching bad weather situation, a true "Catch 22" exists. Additionally roof operators often tie off/safety the roof in its show position, for reasons of safety to likely prevent roof from falling straight down, and to sometimes allow greater weight/equipment to be hung from roof then the combined lifting capacity of the chain hoists allows. However this precludes any safe movement of the loaded roof, since the chain motors would be instantlly overloaded if the safeties were removed. Additionally someone has to make a choice to place euipment under roof which restricts its lowering, however in a life or death situation, it likely possible that this underaneath/hanging equipment could just simplely be allowed to be crushed, but few roof operators would make that decision, but it has been done.

These style roofs can be bought over the phone, are an off the shelf item, with a only a checkbook. There are no requirements for safe set-up, training, safety plans, nor operation required. They are often bought by other vendors (sound, lighting, trucking, etc) and serve the purpose of a vendor now offering to the cost concious promoter an "all in one price", with little regard for the expertise in their operation of the "load bearing roof structure".

Who edited this Wikipedia entry?
Judging from the content and style of the writing, it appears that someone connected to litigation edited the wikipedia entry for the Indiana Stage collapse. The times listed are suspiciously specific and the entry looks more like someone introducing evidence, rather than editing a wikipedia entry. Investigation into who edited this page would be interesting. — Preceding unsigned comment added by 152.228.95.249 (talk) 16:03, 1 May 2012 (UTC)


 * If you are referring to the "someone" who added comments under the heading "Construction Details", it is John Clark, with college level Mechanical engineering background, with 50+ years of experience in high rise construction and concert production in designing, fabrication, erection and operation of load bearing concert roof systems, with probably the safest track record in the industry. I have zero connection with this accident, and only shared a quick analysis based on public available info/video in my comments, nothing more. 2601:6C3:100:4CC0:61EF:361B:F509:B8EE (talk) 11:04, 23 May 2024 (UTC)

Causes section
I added a new section about the causes as found by Thornton Tomasetti, the firm hired to investigate the accident. All the information comes from that report. I have paraphrased some of the longer points, and simplified some of the technical wording to be more readable by a general audience. I welcome any feedback if you have any. TWCarlson (talk) 11:22, 14 June 2012 (UTC)