Commissioned Report on Indiana Fair Tragedy
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Re: Commissioned Report on Indiana Fair Tragedy
Report: Collapsed Indiana State Fair stage rigging that killed 7 didn’t meet safety standards - The Washington Post
A highlight from the article:
The company determined that parts of the rigging’s support system began to give way at gusts of 33 mph and that by the time they reached 43 mph, the structure could no longer support itself. Testing showed gusts of 25 mph could have caused the structure to collapse.
“Once gravity had taken over there was essentially no way the structure could support itself,” Nacheman said. “Gravity takes over and the structure fails.”
The report says the stage structure had support wires attached to concrete barriers used as ballast to hold it in place, but that the system was inadequate to withstand lateral forces such as high winds and was “grossly inadequate.”
The state hired Thornton Tomasetti to review the stage structure and Washington-based Witt Associates to investigate the fair’s emergency plans and response.
Charlie Fisher, a vice president for Witt Associates, told the commission that “an ambiguity of authority” resulted in confusion and uncertainty over who was in charge of public safety as officials discussed whether to postpone the concert just before strong winds blew stage rigging onto waiting fans.
He said fair organizers’ overall state of preparedness “was not adequate” for an event that size, their emergency response plan and procedures weren’t fully developed, and they didn’t utilize the plans they did have on the night of the collapse.
Report: Collapsed Indiana State Fair stage rigging that killed 7 didn’t meet safety standards - The Washington Post
A highlight from the article:
The company determined that parts of the rigging’s support system began to give way at gusts of 33 mph and that by the time they reached 43 mph, the structure could no longer support itself. Testing showed gusts of 25 mph could have caused the structure to collapse.
“Once gravity had taken over there was essentially no way the structure could support itself,” Nacheman said. “Gravity takes over and the structure fails.”
The report says the stage structure had support wires attached to concrete barriers used as ballast to hold it in place, but that the system was inadequate to withstand lateral forces such as high winds and was “grossly inadequate.”
The state hired Thornton Tomasetti to review the stage structure and Washington-based Witt Associates to investigate the fair’s emergency plans and response.
Charlie Fisher, a vice president for Witt Associates, told the commission that “an ambiguity of authority” resulted in confusion and uncertainty over who was in charge of public safety as officials discussed whether to postpone the concert just before strong winds blew stage rigging onto waiting fans.
He said fair organizers’ overall state of preparedness “was not adequate” for an event that size, their emergency response plan and procedures weren’t fully developed, and they didn’t utilize the plans they did have on the night of the collapse.
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Re: Commissioned Report on Indiana Fair Tragedy
Thank you for the link. Nice comprehensive read about their emergency procedures. Looks like no one person had the power to call the show, and those closest to having that didn't have timely weather info.
However, WTF?: "There was no device to measure wind speed near the Structure."
Even the smallest roof companies in my end of the world mount an anemometer directly to the highest point on the structure. You'd think Mid-America would have a road case dedicated to that out with every roof system. How do you know (and prove to the promoter) that limits are being reached without it?
Then again, Mid-America hid behind their lawyers so their input to this investigation is extremely limited.
What really sucks is that Doppler radar has the ability to measure the windspeed, landspeed, and direction of gust fronts and outflows. At the very least anyone out with a roof should have a good radar app and be trained to read it. Anyone with a smart phone or ipad can do that now.
Maybe my standards are just too high.
Thank you for the link. Nice comprehensive read about their emergency procedures. Looks like no one person had the power to call the show, and those closest to having that didn't have timely weather info.
However, WTF?: "There was no device to measure wind speed near the Structure."
Even the smallest roof companies in my end of the world mount an anemometer directly to the highest point on the structure. You'd think Mid-America would have a road case dedicated to that out with every roof system. How do you know (and prove to the promoter) that limits are being reached without it?
Then again, Mid-America hid behind their lawyers so their input to this investigation is extremely limited.
What really sucks is that Doppler radar has the ability to measure the windspeed, landspeed, and direction of gust fronts and outflows. At the very least anyone out with a roof should have a good radar app and be trained to read it. Anyone with a smart phone or ipad can do that now.
Maybe my standards are just too high.
Re: Commissioned Report on Indiana Fair Tragedy
All reports (including the engineering report) can be found here: IN.gov: Investigative Reports
Warning, the full Thornton Tomasetti report is huge. The Executive Summary is here: http://www.in.gov/sfc/files/041212_TT_Exec_Summary.pdf
Doesn't look good for Mid-America or Thomas Truss.
All reports (including the engineering report) can be found here: IN.gov: Investigative Reports
Warning, the full Thornton Tomasetti report is huge. The Executive Summary is here: http://www.in.gov/sfc/files/041212_TT_Exec_Summary.pdf
Doesn't look good for Mid-America or Thomas Truss.
Re: Commissioned Report on Indiana Fair Tragedy
Over 500MB for the full report, but it's worth a look. Thousands of pictures of broken welds, base metal failures and other ways of breaking things. Thorough analysis of the Jersey barricade vs. earth anchoring, too.
Thanks for the links.
Over 500MB for the full report, but it's worth a look. Thousands of pictures of broken welds, base metal failures and other ways of breaking things. Thorough analysis of the Jersey barricade vs. earth anchoring, too.
Thanks for the links.
Re: Commissioned Report on Indiana Fair Tragedy
Would this have happened if there had been no video? In any of your areas have they clamped down on having swings on the temporary structure?
Would this have happened if there had been no video? In any of your areas have they clamped down on having swings on the temporary structure?
Re: Commissioned Report on Indiana Fair Tragedy
Thanks Bonnie,
This should be required reading for all of us. Personally, I got through the executive summary and the Powerpoint this morning. The Powerpoint gives a good visual overview for how well they can re-create and model the stage and collapse. Thornton Thomasetti are the well known in these kinds of analysis, and it should be a gut check for everyone here to see how detailed, and thorough, they can be about what failed when, why, and how.
Thanks Bonnie,
This should be required reading for all of us. Personally, I got through the executive summary and the Powerpoint this morning. The Powerpoint gives a good visual overview for how well they can re-create and model the stage and collapse. Thornton Thomasetti are the well known in these kinds of analysis, and it should be a gut check for everyone here to see how detailed, and thorough, they can be about what failed when, why, and how.
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Re: Commissioned Report on Indiana Fair Tragedy
To be honest; I don't think I've ever noticed a such device on the outdoor stages/roofs that that I've set-up*.
*I don't own any staging structures and/or roof systems. I am working as a freelance "tech", "hands", aka "dumb labor" for these set ups.
To be honest; I don't think I've ever noticed a such device on the outdoor stages/roofs that that I've set-up*.
*I don't own any staging structures and/or roof systems. I am working as a freelance "tech", "hands", aka "dumb labor" for these set ups.
Re: Commissioned Report on Indiana Fair Tragedy
I've worked on several stages where either the promoter or roof supplier had an on-site weather guy with a radar feed from a commercial service (Barrons, IIRC, delivered by XM) and weather instruments. Most of the time, though, the anemometer isn't at the peak of the roof. Based on what's in the report I think more than 1 anemometer might be in order, too.
In one of these situations a storm blew up so fast that the 2 minute delay from NOAA to the commercial supplier to end user was sufficient that the storm was visible and obvious by the time it showed up on the computer. And it hit about a minute later. Significant damage to roof, although it stayed upright. This was a 'popcorn' storm that can just happen and be gone in 15 or 20 minutes. The instrumentation and radar can't do much when a storm takes under 5 minutes to build and hit.
If you're reading the Thornton Tomasetti report, pay attention to some key elements: the contractor appears to have not requested new engineering review from James Thomas for the 2011 roof loading or the guying configuration (that was very different from 2010) and the engineering done for James Thomas in 2010 is repudiated by Thornton's calculations. TT also found issues with the design of the "fin plate" lifting components as well as defective or failed welds.
While this is only 1 report, and Thomas and Mid America will have their own experts in court, it doesn't look good for either of them. The state fair committee gets their shellacking from the report by Witt Associates regarding their emergency planning as well as some pointed questioning by TT about the Fair not requiring current engineering documents and an on-site roof engineer to supervise the build and superior loading of the roof.
I used the word "appears" above. I picked that word because neither Mid America or James Thomas Engineering cooperated in the Thornton Tomasetti investigation, choosing to claim "trade secret" status for much of their involvement. I find Thomas' use of this interesting because some of the documents and base engineering info for components of the structure are available on the Thomas web site.
Time will tell. The only thing "for sure" is that temporary demountable structures will come under much greater scrutiny and regulation. The costs will go up accordingly and there will be further pressure on sound, lighting and video to lower their prices. It will suck.
I've worked on several stages where either the promoter or roof supplier had an on-site weather guy with a radar feed from a commercial service (Barrons, IIRC, delivered by XM) and weather instruments. Most of the time, though, the anemometer isn't at the peak of the roof. Based on what's in the report I think more than 1 anemometer might be in order, too.
In one of these situations a storm blew up so fast that the 2 minute delay from NOAA to the commercial supplier to end user was sufficient that the storm was visible and obvious by the time it showed up on the computer. And it hit about a minute later. Significant damage to roof, although it stayed upright. This was a 'popcorn' storm that can just happen and be gone in 15 or 20 minutes. The instrumentation and radar can't do much when a storm takes under 5 minutes to build and hit.
If you're reading the Thornton Tomasetti report, pay attention to some key elements: the contractor appears to have not requested new engineering review from James Thomas for the 2011 roof loading or the guying configuration (that was very different from 2010) and the engineering done for James Thomas in 2010 is repudiated by Thornton's calculations. TT also found issues with the design of the "fin plate" lifting components as well as defective or failed welds.
While this is only 1 report, and Thomas and Mid America will have their own experts in court, it doesn't look good for either of them. The state fair committee gets their shellacking from the report by Witt Associates regarding their emergency planning as well as some pointed questioning by TT about the Fair not requiring current engineering documents and an on-site roof engineer to supervise the build and superior loading of the roof.
I used the word "appears" above. I picked that word because neither Mid America or James Thomas Engineering cooperated in the Thornton Tomasetti investigation, choosing to claim "trade secret" status for much of their involvement. I find Thomas' use of this interesting because some of the documents and base engineering info for components of the structure are available on the Thomas web site.
Time will tell. The only thing "for sure" is that temporary demountable structures will come under much greater scrutiny and regulation. The costs will go up accordingly and there will be further pressure on sound, lighting and video to lower their prices. It will suck.
Re: Commissioned Report on Indiana Fair Tragedy
I agree with you Tim prices will go up as they have over here, a wind speed measurment taken locally is about all you can do for local storms, and with a rig that big then all that can be done is evacuate the area, because as the report says there's no way you're bringing that pile of gear in in 5 mins, hopefully some good will come of all this though i suspect it'll take time but maybe providers for this season will think a little harder about guying these things and or use self supporting stages. G
I agree with you Tim prices will go up as they have over here, a wind speed measurment taken locally is about all you can do for local storms, and with a rig that big then all that can be done is evacuate the area, because as the report says there's no way you're bringing that pile of gear in in 5 mins, hopefully some good will come of all this though i suspect it'll take time but maybe providers for this season will think a little harder about guying these things and or use self supporting stages. G
Re: Commissioned Report on Indiana Fair Tragedy
There's one important point made in the forensic engineering report (which I don't have on this computer, so I'll paraphrase): Bringing in the roof is not an option under any circumstance.
Doing so would have the same effect as simply cutting all of the guy wires and greatly lowering the max wind speed the assembly can handle.
There's one important point made in the forensic engineering report (which I don't have on this computer, so I'll paraphrase): Bringing in the roof is not an option under any circumstance.
Doing so would have the same effect as simply cutting all of the guy wires and greatly lowering the max wind speed the assembly can handle.
Re: Commissioned Report on Indiana Fair Tragedy
No need to cut them. One of Thornton Tomasetti's disputes with the Thomas engineer's 2010 study was that 1/2" wire rope guy lines specified by Thomas were, in fact, insufficient for the load. In TT's recreation of the collapse, they point to the initial sliding movement of some of the Jersey barricade (K rail) and the subsequent failure of guy lines. One of the reasons guys failed was due to use of 3/8" wire rope, mixed with 1/2". One of the questions for Mid America will be "why were these materials used when Thomas specified a stronger product"?
I'm still digesting this report and looking at the various modes of failure at different points in the collapse. It will be interesting to see how all this plays out in court.
No need to cut them. One of Thornton Tomasetti's disputes with the Thomas engineer's 2010 study was that 1/2" wire rope guy lines specified by Thomas were, in fact, insufficient for the load. In TT's recreation of the collapse, they point to the initial sliding movement of some of the Jersey barricade (K rail) and the subsequent failure of guy lines. One of the reasons guys failed was due to use of 3/8" wire rope, mixed with 1/2". One of the questions for Mid America will be "why were these materials used when Thomas specified a stronger product"?
I'm still digesting this report and looking at the various modes of failure at different points in the collapse. It will be interesting to see how all this plays out in court.
Re: Commissioned Report on Indiana Fair Tragedy
I only glanced at the 1500 Page report from TT, but I questioned myself on something.
Does a trussing structure have a "shelf life" like for fire safety suit (example)? Lookin at the pictures; some of the truss was manufactured in 1995.
I only glanced at the 1500 Page report from TT, but I questioned myself on something.
Does a trussing structure have a "shelf life" like for fire safety suit (example)? Lookin at the pictures; some of the truss was manufactured in 1995.
Re: Commissioned Report on Indiana Fair Tragedy
I'm not sure about truss, but with airplanes, when they go in for the teardown and rebuild, all of the structural welds are x-rayed and the structural pieces are checked by ultrasound, and all defects must be repaired or replaced.
I'm not sure about truss, but with airplanes, when they go in for the teardown and rebuild, all of the structural welds are x-rayed and the structural pieces are checked by ultrasound, and all defects must be repaired or replaced.
Re: Commissioned Report on Indiana Fair Tragedy
It should be clarified that lowering the roof would compromise the lateral load resistance. The roofs are specifically designed so that the lateral loads bending moments are not coupled to the tower, as it should be. Since the guy wires are bearing the lateral forces lowering the roof would make these wires too long to provide tension, and remove the resistance to lateral loads.
It should be clarified that lowering the roof would compromise the lateral load resistance. The roofs are specifically designed so that the lateral loads bending moments are not coupled to the tower, as it should be. Since the guy wires are bearing the lateral forces lowering the roof would make these wires too long to provide tension, and remove the resistance to lateral loads.
Re: Commissioned Report on Indiana Fair Tragedy
For those that want to have a look, the salient engineering calculations are primarily in Appendices D and E. The appraisal of the existing calculations is in section D.10. Reading all of this was like a throwback to my college mechanics of materials classes.
Perhaps the biggest "reading between the lines" for me in here has nothing to do with the anchoring, the guy wires, or the changes in geometry from shifting barriers.
Namely, if the structure had been adequately anchored from permanent points, using guy wires of sufficient tensile strength, the loading of the attachment plates for the guy lines was going to be sufficient to fail either the plate weldments (what happened) or the tubular members they were attached to.
I'm not a structural engineer, or a PE, but I've had to to the types of calculations that are in the report. If your guying method can load the guy attachment plates to failure, then you need a new guying methodology. No amount of better/permanent barricades, stronger guys, or the like will compensate for this detail.
For those that want to have a look, the salient engineering calculations are primarily in Appendices D and E. The appraisal of the existing calculations is in section D.10. Reading all of this was like a throwback to my college mechanics of materials classes.
Perhaps the biggest "reading between the lines" for me in here has nothing to do with the anchoring, the guy wires, or the changes in geometry from shifting barriers.
Namely, if the structure had been adequately anchored from permanent points, using guy wires of sufficient tensile strength, the loading of the attachment plates for the guy lines was going to be sufficient to fail either the plate weldments (what happened) or the tubular members they were attached to.
I'm not a structural engineer, or a PE, but I've had to to the types of calculations that are in the report. If your guying method can load the guy attachment plates to failure, then you need a new guying methodology. No amount of better/permanent barricades, stronger guys, or the like will compensate for this detail.
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Re: Commissioned Report on Indiana Fair Tragedy
Matt,
Aluminum alloys exhibit "low cycle" fatigue life behavior, but they don't really have a fixed degradation with age. Aluminum is reasonably chemically stable against corrosion, so there's not a huge chemical reaction component.
I forget the gory details of aluminum fatigue life, but I do remember that welds for common alloys like 6061 can be susceptible to it on comparatively low number of loadings (<10e4).
Routine truss inspection by standard metallurgical means would be a very good idea for the industry.
Matt,
Aluminum alloys exhibit "low cycle" fatigue life behavior, but they don't really have a fixed degradation with age. Aluminum is reasonably chemically stable against corrosion, so there's not a huge chemical reaction component.
I forget the gory details of aluminum fatigue life, but I do remember that welds for common alloys like 6061 can be susceptible to it on comparatively low number of loadings (<10e4).
Routine truss inspection by standard metallurgical means would be a very good idea for the industry.
Re: Commissioned Report on Indiana Fair Tragedy
Yeah, that's what I said.
~:-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?"
Yeah, that's what I said.
~:-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?"
Re: Commissioned Report on Indiana Fair Tragedy
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?
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?
Re: Commissioned Report on Indiana Fair Tragedy
Let me repeat myself: Lowering the roof IS NOT AN OPTION when winds or bad weather is present. Lowering the roof makes the entire assembly even MORE unsafe because it unloads the guy wires.
Let me repeat myself: Lowering the roof IS NOT AN OPTION when winds or bad weather is present. Lowering the roof makes the entire assembly even MORE unsafe because it unloads the guy wires.