Newly Constructed Gym Has Roof Collapse in New Mexico 12

[jerseyshore]

https://www.kob.com/new-mexico/gym-roof-collapses-at-charter-school-sparking-safety-concerns/

ALBUQUERQUE, N.M. — In-person classes have been canceled at a local charter school for the rest of the week after the roof of its new gym collapsed.

School officials say the new gym at the Explore Academy middle and high school campus was basically complete. They were even planning on hosting a ribbon cutting Wednesday, but that’s been canceled, as well as all in-person classes.

Parents learned about the collapse through an email from the school Sunday night.

“The students are out the whole week now,” a parent told KOB 4 anonymously. “Because they have to get inspectors to gather and, at the request of the inspectors in particular, for students to stay away until they can just look the whole thing over.”

The parent said the incident has raised many more concerns about sending her child back to school.

“Students were going to be in that building in two days, and I think one of the big questions I personally have is, did it pass the inspection already?” the parent asked.

The answer is no. KOB 4 spoke with a rep from Albuquerque’s Planning Department. They said the construction company, AIC General Contractors, failed a building frame inspection on March 6. Inspectors found the trusses bowing or bending.

The city’s Planning Department didn’t know the roof had caved in until KOB 4 called Monday afternoon.

Explore Academy leaders say, as of now, it’s just the new gym that seems to be impacted, but they aren’t taking any chances.

“They discovered the damage and evaluated the situation and decided that we would go ahead and go to asynchronous learning until we have a sign off that the entire building and structure is, in fact, safe for students to enter,” said Katia Pride, Explore Academy’s director of outreach.

Pride said there was no obvious damage to nearby classrooms. The school will also have to bring in an engineering company to create a repair plan.

The city’s Planning Department will be sending a building complaints investigator to figure out what went wrong.

 

[TheGreenLama]

Zero discussion about investigating the roof collapse during the NM Public Education Commission public meeting that was held April 19th, eleven days after the event. Collapse was only mentioned in passing.
Link

 

[Sym P. le]

The link doesn't work.

 

[3DDave]

Seems OK - downloaded a pdf.

https://webnew.ped.state.nm.us/wp-content/uploads/2024/05/April-19-2024-PEC-Meeting-Transcript.pdf

50+ pages of index of each word in the entire document, including numbers. Why? It's a PDF which is searchable.

 

[KevinK2]

On the pilaster opposite of which has been posted a few times,you can see what appears to be two studs protruding up through the bearing plate, as well as what appears to only be 3" to 4" of bearing area as they sat it down.

Those 2 "bolts" act more like pins spaced wider than the cord. The video shows the top cord being slid sideways into the pocket above those pins, then being dropped down between them.

The installers appear to be working at both cord-pocket connections, but it's not clear what they did to secure them during 2 trips up the sissors platforms.

As others suggested, I believe the root-cause of the failure had to do with the installation of the roof, but with a likely flaw in the truss. In the post failure video, the truss appeared to remain straight, but folded at a hinge zone at about 1/4 to 1/3 of the span away from the right side pilastra.

The longer truss span stayed attached at the left pilastra, and the right cord end appeared to have crushed the outer edge of the supporting concrete as it was pullled out of the pocket during the collapse. As the truss began to hinge at that zone, it also pulled the right cord from it's pocket. This hinge deformation ended when the support on the right side ended, and the net shortened length of the truss span explains why there were no vertical scars on that painted wall on the right side.

It's possible the hinge was really buckling at the open truss square, or the diagonal in the next one away from the wall.

This slow creep-like failure theory is consistent with the measured, gradual bowing/bending of the lower truss reported on March 6 during an inspection. It was noted but still within installed tolerance then, but another check ~2wks? later showed more bowing/bending beyond tolerance, and construction was stopped.



Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[1503-44]

I do not think getting round back to the open truss panels is a coincidence.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[Brad805]

If the design of the trusses assumed the unsupported length of the top chord equals the panel width, and the actual unsupported length is more like 1/2 the truss length, the capacity of the top chord will drop to collapse levels. The pictures do not indicated a lot of top chord bracing other than friction so far and that would support the conclusion the top chord is lacking lateral support. We investigated a collapse in the 90's where the top chord of a bowstring truss was not supported correctly. In that case it took almost 30years for the wood chord to creep, and ultimately collapse, but the dead loads were more like 15% of the design load. Here I suspect the dead load would be more like 80% of the design load. It is not hard to understand the failure speed if any of that is true.

The normal companies that built this type of truss know how to do this, and that is all they do. If they elected for a custom fab shop, then who knows. Another factor I would be curious to know is the amount of design delegation. In this case we have a truss supplier, and hollow core supplier. Things falling thru the cracks is not unheard of.

 

[JJohns]

My first time here, but have there not been any posts since May 10? Previously there were posts almost daily. I think the possible causes have been well detailed, and it appears to me the failure was a combination of factors - Lateral Torsional Buckling, missing diagonals in high shear bays at either end, lack of adequate bearing due to construction sequencing, possible compression failure at edge of pilaster due to top chord bending, lack of anchoring of top chord to roof, very heavy concrete roof, lack of lateral bracing. It is my understanding that a local structural engineering firm has been tasked with the investigation. It is hard to understand how it could take so long unless legal implications have complicated releasing a report.

 

[Sym P. le]

No.

Yes.

A reasonable summation.

Do tell!

Material testing, collecting relevant documents and communications, theoretical analysis to name a few other possible complications.

 

[1503-44]

They'll be a year at it.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[3DDave]

In the tea leaves: This failure is from something fundamentally stupid, so fundamentally stupid that the person/organization responsible will settle with no public record of the reason for the settlement so as to avoid future clients from tying this disaster directly to them. Even if it is a one-off brain fart and they do excellent work elsewhere and anyone hiring them in the future would be fortunate to get them, the stigma would call into question those who let such a contract.

I think it is reasonable to expect the person/company to change names and maybe address as well; if a person they will get a new LLC.

This will get buried like the New York trail bridge that had the misfortune of no one making a bending moment diagram and looking at the section properties everywhere along that diagram.

No one died, no one was injured. It's a tax dollar problem and money hides money.

Or so the tea leaves suggest.

 

[LittleInch]

JJohns,

Not only that but if you go gooogling, the only things that pop up after the first day or two is this site!

This has gone into the weeds, I think in part due to lack of available information or drawings, no video of the collapse released to the public and no one got injured or killed. Basically no one wants to actually work out what happened in public so as to avoid all the issues 3DD aludes to is my opinion.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.