This sucks....., some garbled accounts say the crane caused it, collapsing first, others just say it was involved. Across the state from me, but still hits home.https://www.today.com/video/crane-collapse-at-boise-airport-hangar-kills-3-injures-several-203395653912
A better link:
The "lawyers" are already circling.
Shades of the Big Blue collapse?
It is not one big canopy like Big Blue. We'll see what comes out in the investigation.
It's a real big deal here, the biggest construction snafu in a long time, and the worst, right by a busy freeway also, if I'm not mistaken. I avoid that side of the state, way too busy nowadays.
Its a horrible event. 3 guys will never get to go home and another 5 in the hospital with critical injuries and a couple more hurt. Its a airport hangar, big open span. Here's a picture from a day earlier when they were getting going. Multiple crane lift, hanging a full bay at a time. We've done buildings this way, but not at this long of a span. I set one a few years ago that was 100' wide, but we did it a rafter at a time, so not as much weight, and full locked each rafter in as we were going. Weather from yesterday- 20 mph winds. So here's my early guess, bays stood, but not enough purlins put in between stood bays. They put in enough purlins to hold the bays apart- and then on to the next bay. Get the extra cranes off site and come back and fill in later. Only one crane in the middle in the accident pictures, so (my guess) they were using it to fill in purlins between the bays that were set. He was holding a purlin when it went over, and it took the crane boom with it. Wind at 20 mph gets the building to moving, no x braces/ cables holding it all together yet. Guys all up in the lifts installing purlins and locking it all together. So when the wind got up on it and got it moving, down like a house of cards. Taking down the crane, the guys in the lifts, and the guys on the ground prepping everything were right in the bad zone too.
That is as good a take as any. Always in a hurry, like the ironworkers taking down the tower that fell in Seattle.
Time is money, its always been that way, and always will. Its hard to be the one to say "we need to get some more bracing on this"......
you do it, I do it.
Unfortunately, no one there had the guts to.
It wasn't tragic but being in a hurry and not putting enough braces is what caused several huge girders on a new bridge to buckle a few years ago up here. They had to bring in one of the largest rubber tired cranes to remove the damaged girders. I forget how big but there was only 1 local company that had a big enough crane and there's only a couple of them in Canada if I remember right. I think it was over 500 tons, 550 maybe??
I'm way wrong. I just did a quick Google search. The crane had to be brought in by truck loads because it was so big... 1200 tonnes! The 3 buckled girders were 40 tonnes each but they needed to support the rest of the bridge so the girders could be removed. Miraculously they were able to repair the girders. Only 7 of cranes in N. America. It's nicknamed the Irish Rover and is a Liebherr LTM 11200-9.1.
I don't know a thing about steel, but Crane Op's take is pretty similar to what happens with wooden trusses. We have had several episodes in my area with truss systems coming down in the wind because they weren't braced well enough.
Looking at some more pictures this morning. Looks like first bay had all the purlins in and x braced. You can see the crane is sitting in the bay that's still having purlins added. So they set two rafters with purlins in them (one bay), skip to the next twin rafter set- and right down the building. Coming back later to finish in the purlins. The only other thing that I have done, and I can't see if they had this done here - I've installed cables up and down the rafter (bay) section to concrete blocks or deadmen on the ground, to take the sway out of the center of the building. Its a pain in the ass because the cables are in the way for the lifts and getting around inside the building. Plus you have to get the concrete guys to pour the deadmen in as they are putting in footers. It also takes time to put the cables up, while you could be putting in purlins. But at least it gives you something to tie off the bays to, while you are getting it all locked together.
That's just all one horribly expensive pile of scrap steel now. Bring in the scrap dealers, cut it all up and start all over again, at massive additional cost. All because someone failed to understand building construction basics.
We got a schedule to meet boys. No time to stop for wind.
I set all six of my steel main frames with my single "Fred" truck by myself. Once in place I anchored them with mobile home screw anchors into the dirt and rope pulleys until the sidewall girts and roof purlins were firmly in place. I started in the center and worked out toward the end walls. Mine is only 70' free span so nothing in comparison to this hanger but I learned a lot doing that.
I did two small commercial jobs in '23 for a construction company with the same name, but it must be a different branch or something as I didn't send the bill to Boise. But the name is the same, the guys I worked with were a step above average, I got a free lunch, no one rushed things, and I got paid quicker than usual. Inland Crane has been around for decades, FWIW. That building looked like, what, 150' span? A whole different can of worms from a "mere" 100' span, no engineer here just an old carpenter, but I bet the loading go up expotentially real quick. I've seen contractors here, home builders, get in trouble when they take on a 60' span 16' high warehouse type structure, in fact the house set crew I did yesterday lost a guy on just such a job about 5 years ago, min bracing was the reason, luckily I wasn't involved. It'd be interesting to know if the crew had worked on such a large span before.
How fast do you think they will find qty (3) replacement workers ? got to make up for lost time eh ?
Never time to do it right, but always find time to do it over.
I posted about this on a flying forum, it being a hangar, and have gotten a few comments by Boise area pilots saying it was "super windy" that day. A sdeep a chord as those huge beams had, that's alot of wind push.
Really bad people had to die and get injured because they couldn't wait for a calmer day.
Besides the usual rules of thumb that I was taught such as: ~ first completing all the columns including girts and especially flange braces ~ portal frames (if any) installed too ~ choosing the first and second main frame to place from a braced bay .... has anyone experience with the use of a "temporary support tower" added to provide support at the peak of the main frame - to so to speak 'three point support' the main frame rafters until the metal building system is completed?
The company involved is large, Big D is the name. I see them over here on this side of the State and they operate in other states as well. They had numerous OSHA violations in the past years. This was posted on local news apps here. Most it appears to have been tie off violations. They brought in inspectors from all over to investigate this. I know some of the first responders that responded. A lot of great work done in the response to this, that kept the death rate lower than it could have been.
In the past years....sounds like a beancounter is now driving the ship there eh ?
One of the founders of the company Craig Durant, (Big D steel) was one of the guys killed. I find that rarely are the beancounters the ones driving for speed in assembly. Typically beancounters have no push on a ironworking crew. There's no "assembly manual" on buildings this size. There's "industry knowledge" and "best practices" ways to go about building them. There's no engineered wind load factors on the building, as its partially assembled. IT is engineered to withstand wind loads and calculations for such, once its all bolted together and has the steel screwed down. Hindsight is 20/20. I've bolted things up, and seen them wiggle waggle, and decided more bracing was in order. Sometimes you just roll with it, and every purlin you put in, stiffens it all up. These guys got bit by high winds at the wrong stage of assembly. You could do something like that, its how they used to build old railroad bridges and such- build a falsework, assemble the bridge on it, and then pull the falsework out. I've never seen it done on a red iron building. Occasionally for some goofy overhanging cantilevered structures- a falsework might help. I've only used cable bracing on a building like they were building this hangar.
I've seen cables to deadmen made of a cluster of 4000# ecology blocks. It was not this large a building though.
Don't they have to calculate wind load at different wind speeds as part of the reaction process? I remember on the Big Blue collapse the wind load load was huge. I don't know if it's a requirement or not but seems it should be.
I saw some pics with just a few anchor bolts and the bottom plate torn off the upright. Others with no anchor bolts showing. With drill in anchors there isn't the immediate anchoring available with pour in studs.
Big D Builders Inc Big D Builders, Inc. is a steel construction company based in Meridian, Idaho since 1964. www.bigdbuilders.com * The very first image is of the Hanger--Skywest Hanger-listed as a currant on going job.
Going to run full calculations of every possible rafter wind load resistance, at every possible wind speed. And do that calculation at every stage of construction, because the building gets stronger with every piece of steel added. And it also catches more wind every time a piece goes in. And then they will run calculations with every possible angle that the wind can come from, because it makes a huge difference if the wind is 90 degrees to the rafters vs. with the rafter sections. Never going to happen. Its madness to think it would.
You'd think they would at least have an idea of wind loads at the max. wind speed they would do the lift. I know lifts have been postponed due to too high of winds. I don't know if wind speed is the only variable though. Do they consider the capacity of the crane and if the lift is close to that or how far the boom is extended?
Today I just learned the MBMA and the MBCEA "coordinated" a book called Temporary Bracing Guidelines thru the MBI, a non profit formed in 2000. The TofC and the first chapter can be previewed. About $300 or less if one is member of MBCEA.... Printed only and I have yet to learn the number of pages. There's a YouTube video - at Metalcon where the book is introduced in March 2022. At around the 38 min mark there are recommendations for features that are to be added to the base building in order to help with the construction loads: things like bigger anchor bolts, thicker baseplate, eave strut flange bracing, more purlin to flange bracing in the Braced Bays etc etc As I read the power point bullets I wondered why no one mentioned that stuff to me when I order these bldgs - but now I will be more informed.
Of course they had an idea of the wind load. Same seat of the pants we all use. Sometimes it doesn't work out. I've lost one set of trusses in my career. Happened at night and nobody was hurt. Freak windstorm with 60+ mph winds. Didn't just pull all the braces on the gable, it snapped 2x4s and 2x6s in half. I didn't feel too bad about it since most of the trees around the house had blown over too Latest reports say that they were setting an end truss. Could be possible that there was bracing in place but had to be removed to install the last truss. That's complete speculation on my part. I don't know how they do things in steel. In wood frame construction we almost always start at the gables and move inward
I think the size and weight being lifted and potential for disaster needs to be considered. I think wanting to get done faster certainly could have contributed.
Of course it was considered! There was an error in the considerations.
Complacency easily sets in with both scenarios of experience, and inexperience. With having fatalities involved this will be drawn out for years and long after the job is reconstructed and finished up. I've only done one project like this and it was my own. I had no experience then using equipment the safety police would openly ridicule but I wasn't trusting anyone else's judgement, only my own. I didn't want the structure collapsing and well know the winds endured here so I thought braced until firm before moving on. I erected all the columns and girts prior to setting the first roof beam, then the first span, braced it to the ground diagonally with the screw anchors, then the second span bridging the two spans together with purlins. Then moving to the next span and repeating till complete. I had all the purlins bolted before moving to the next starting from the center out towards the end walls.
I didn't know that one of the founders was killed. That wasn't in the article I read. I guess that speaks to how critical this project was.
I read the hanger was supposed to be 39K sqft. Its way wider than deep, so how long were those rafters? If the crane was hanging an end truss, would it be normal to be set up inside the building? The crane placement itself suggests there was a section between trusses that was without purlins.
I don't know how much they can span with that type of truss/girder, but that sure looks like it must be pushing the max....., and I wonder if the crew had worked on a lot of similar appearing, but lesser span buildings, and kinda did similar bracing as that worked before. Yes, 39 K sf, but I never caught the span.
If for example, 150ft. deep, it would have a span of 260ft to equal the 39Ksqf. Arbitrary figures as I have no idea as to sizing.
From local news coverage.
Yes, but as someone pointed out, the building actually looks pretty darn short, not anywhere near 150 long, but that's just a guess. Anyway you slice that's huge span for sure. I don't see the peeled up base plates being the cause, they were never designed to take the load of the entire truss laying on the ground. That does show the tremendous forces involved though, looks like the J bolts did their job.
There are other photos of base plates that were never anchored. That base plate was not completely anchored, as you can see the holes on the opposite side of the web were unused. It seems many have gone away from poured in J bolts to drilled in anchors.
I see Big D in SLC and Jackson frequently.
Just by the pictures, I'm guessing that's around 180-200' wide.
Here is another hanger BigD is supposed to have built, much larger than the one that collapsed.
I have a friend that pours building slabs. He swears that the drilled and epoxy anchors are stronger than the j-bolts, you can only bend so much into a j-bolt.
Its taller, I'm not sure its much wider. The biggest difference is the lattice trusses. They don't catch near the wind that the flanged beam trusses do. Those flanged beam trusses are no fun to work with. They want to twist and tend to be really floppy, until they get all locked in. If you look, they built it the same way they were building the one that collapsed. They have two full bays built, fully purlined in. The open bay between them is minimally purlined, as is the end wall. They aren't in great conditions there either, the flags on those boom tips are standing straight out.
Think they were unused, or they just got sheared off? I've loosened anchors to get some play in the columns when locking up to the main cross beams.
A little hard to tell for sure but looks like it sheared along the toe (edge) of the weld in the heat affected zone. It's possible that proper weld procedures weren't followed such as preheat or too high of interpass temp., possible undercut or even the wrong filler metal. That latter is probably the least likely but that is what could happen if a much higher tensile filler metal than the base metal was used (like 11018 on mild steel where 7018 should be used.) Had both sides been bolted it may not have failed because it wouldn't create a shear condition on just one side of the beam. Generally I think bolts would normally break before you'd shear the metal but it depends on the size of bolts. When use a shear to cut plate it looks just the break. There is only about a 1/4 of the metal thickness that looks like it was cut with scissors (the shiny part). The other 3/4's looks fractured for lack of a better term.
I did a steel hangar like this last summer for a pilot friend, just 40' or 50' span however. I remember when we got the first girder truss (not lattice) up and the guys were busy lining their bolts up, I got out and walked around to the side and eyeballed it and it looked like a noodle, way out of column, though the peak was lined up with the ends. Guesstimating the span...., I'm thinking at least 200', going by the claimed 39,000 sq. footage, it'd help if we knew the distance between the columns.
That's what I'm thinking BIGGER than 200', hard to wrap my mind around that though, but the building just doesn't look that long, so doing the math.....
Just down the road from me they are building a ~60'x120' indoor horse riding arena. Pole barn construction, wood trusses on 2' centers. Saw them putting it up with very little bracing and thought to myself this is probably going to end badly. They had about 1/3rd of them up and one night the wind got up, next morning it was a giant pile of pickup sticks. Luckily happened when no one was there. From what I heard the contractor did not have insurance and landowner was trying to get their homeowners insurance to pay for it (unlikely). What a mess. They put up about half the remaining trusses, braced them and roofed it, I guess they are still trying to figure out who's going to replace all the damaged ones. Another case a few years back, a contractor I know put up a pole barn, had the trusses set and maybe the tin on the roof, but no walls or diagonal bracing on the poles. While away at lunch a wind storm came up and when they came back the whole building had racked over 1-2'. Luckily they were able to get it straightened out and braced before it came down. The wind is no joke...
You are right about that. In my town a couple years back we had a very similar situation to the one you described. The highway department was building a new barn, I don't know the size, but probably at least 120' or so. Contractor set the trusses and went home. That night we had a storm blow through, and the next morning the whole roof system was a pile of demo waste. That contractor didn't have insurance either! How do you get a county job without insurance? I have to send out COI's for way smaller jobs than that one was . . .
I guess I've never worried about my contractors COI on a structure, the furnished COI was for work comp.
Part of the problem is the difference in wind speed at ground level and wind speed at the height of the trusses. You can have a major difference in wind speed, and even direction, with just 50 feet in height, just ask any pilot.
Interesting that J bolts are used, and now they have switched to epoxy ? My own building, I welded them to the re-bar cage. I thought all steel buildings welded the J bolts (or threaded rod) into the re-bar cage for the cement columns/grade beam. At work, we don't use J-bolts for machine tools, we use DECO anchors as they have had J bolts unbend and pull out.
I know nothing of vertical construction, but I was wondering if they poured the J bolts in and were intending to drill and epoxy the remaining bolts after all was in place.
little buildings I work around < 150' wide, the bolts are set and built into all sorts of steel. They are far from a simple J-bolt.
Had an hanger being built at the municipal airport, stick frame. They starred sheathing the building, got the one corner done towards the prevailing winds but the next day the winds came from the other direction and ripped the whole thing down like a kid squashing a popsicle stick house.
This is getting full attention. Allot of armchair.
Why would you spend the money for weldable rebar? Then how do you segregate it?
Big D has been doing a job at the local university here, and today on the way out of a hardware store as I was leaving the parking lot, I saw one of their trucks, and a guy walking toward it. Having worked for them myself last year (at least they were the general on the charter school project, I worked for the framing contractor) I was going to ask him about the span, just that, nothing more. But it was some other guy so I just drove off.
It wasn't welded, a bunch of hoops and vertical bars, and the J bolts were hooked under that bar. They had not set the bolts on this outside column yet. They missed some bar and had to drill and epoxy a couple more hoops at each footing. The bolts were turned out and under the bar seen here. Sorry I don't have a better picture. It was incidental at the edge of another picture.
I was responding to Digger's comment on welding rebar. My last two buildings had drilled in anchors. The drilled in anchors are always in the right spot, unless you hit rebar drilling them in. But you have nothing to anchor the structure until the epoxy sets, where poured in anchors are solid as soon as you set the nut.
Although it looked pretty obvious the crane wasn't the cause, I did watch a YouTube video where they said Inland Crane made an official statement that their crane wasn't the cause and it was a structural failure in the building. Also reading some of the video comments there was someone saying that there were "cables snapping" the day before and the day it collapsed. Who knows where he got that info or if there's any truth to it.