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Hard Rock Hotel under construction in New Orleans collapses...
81

Hard Rock Hotel under construction in New Orleans collapses...

RE: Hard Rock Hotel under construction in New Orleans collapses...

Wow, obviously not good. Really pulling for the worker on the scaffold (on the southwest elevation (yellow side) about 3 floors up from the podium (white) level).

Video seems to start a little after the collapse starts.

EIT
www.HowToEngineer.com

RE: Hard Rock Hotel under construction in New Orleans collapses...

Never have been a proponent of PT flat slab construction. Too many things can go wrong that can lead to what you see here due to the lack of redundancy, if nothing else.

Mike McCann, PE, SE (WA, HI)


RE: Hard Rock Hotel under construction in New Orleans collapses...

If you watch the beginning over and over, it looks like the top two slabs deflect a column line or two in from the edge. The edge of the top slab rotates and is pulled back. Looks like those slabs failed in flexure first.

That one crane in the background tilts forward as if it was resting load on the slab and the slab just gave way.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The images linked by stookyfpe show steel framing, steel form deck, etc. Not PT flat slab at the levels which collapsed. It looks like the transfer floor is intact.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Jeremy,

The video is the final stage of the failure. Most of that side of the building had already collapsed. What we see here appears to be the last few dominos to fall.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Yes, this is well underway when the video starts. Certainly looks like just the steel frame falls. I think the PT level we see in google maps is the top transfer level. Look how thick the slab is right at 115 seconds

Check out the rubble. Here's some drone footage.

RFreund, click on that link again, the worker is now blurred. I noticed him too when I first saw it.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (msquared48)

Never have been a proponent of PT flat slab construction. Too many things can go wrong that can lead to what you see here due to the lack of redundancy, if nothing else.

Purely based upon photographs, I think the PT deck (transfer level and those below it) fared considerably better than the structural steel with metal deck-slab.

Lower levels with PT:



Upper level with structural steel + metal deck:

RE: Hard Rock Hotel under construction in New Orleans collapses...

@dold - dang, not a good sign. I thought he could have snuck in that window.

EIT
www.HowToEngineer.com

RE: Hard Rock Hotel under construction in New Orleans collapses...




Check out the steel framing and deck orientation in the cantilever...where those small canti tubes supposed to hold the floor up? The shoring appears to fail, but this appears to be some weird, inadequate framing

RE: Hard Rock Hotel under construction in New Orleans collapses...

That is going to be a mess to clean up.

The video is curious. It was shot by hand and started while the collapse was in progress. So it had started several seconds earlier and that person was super quick to the draw or it was just a strange coincidence. I'd be interested to hear more about why he started recording.

RIP to the departed.

RE: Hard Rock Hotel under construction in New Orleans collapses...

There was one recording started by a guy in the construction industry who claimed to have heard from a block away the sound of something hitting the ground, he thought glass, near the construction site. I assume he's heard a similar noise before, so he stopped his car and started to look for the source while recording. This is the one that catches the steel frame chasing 4 or 5 workers as they flee across the street.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Ingenuity...

The podium slab protected the thinner slabs below.

My opinion has not changed.

Mike McCann, PE, SE (WA, HI)


RE: Hard Rock Hotel under construction in New Orleans collapses...

Mike,
You are entitled to your opinion about flat plates, but your comment was misplaced here. This collapse would seem to have nothing to do with the concrete construction at and below the podium level.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Hokie. You are right. Vent over...

Mike McCann, PE, SE (WA, HI)


RE: Hard Rock Hotel under construction in New Orleans collapses...

Looks like the rock was not hard enough.

Mike McCann, PE, SE (WA, HI)


RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (ABC News)

Officials said it appeared the collapse initially affected the sixth to eighth floors before damage spread throughout a large portion of the building

RE: Hard Rock Hotel under construction in New Orleans collapses...

2

Quote:

Apparently risk of additional failure

That's not particularly surprising; the loading on the building is completely messed up and there are missing and damaged beams on the portion that survived.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Hard Rock Hotel under construction in New Orleans collapses...

In the video it looks as though the edge beams and column grids stayed largely intact, and fell outwards as a frame, with the decks all slipping/breaking off.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (ABC News)


Officials said it appeared the collapse initially affected the sixth to eighth floors before damage spread throughout a large portion of the building

The hotel was (to be) 17 or 18 floors - the first 5 or 6 were parking (PT floor framing), then a PT podium deck supporting 10+ (?) floors of hotel and condo framed in steel + metal deck. Presumably when they state "...affected the sixth to eight floors..." they are referring to the upper hotel floor framing - measured above the podium deck.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Nice video:
https://www.youtube.com/watch?v=ZP4tbb8omHc

To add up on the note of
structuralengr89
These cantilevers are having a shoring above which seems not loaded on the beams below this might be the case of it might be shifted during the collapse

Also, it is noted that the steel columns in the upper typical floors are shifted from the columns below. This discontinuity could accelerate a progressive collapse.

Lack of shoring is a factor in these systems where the deck is designed to be the form work. The structure seems to be very optimized with light sections at the typical floors that noway it could handled an additional weight on the horizontal or the vertical element (ideally it would not be required to)


If the design is concluded to be done properly a probable cause is the localized failure of floor bay had a domino effect on the others above and below and that one or two bays caused it all.

The podium slab indeed performed well!

You never can tell by pictures and videos, much more need to be reviewed.

RE: Hard Rock Hotel under construction in New Orleans collapses...

(OP)
To say nothing of the tubs of debris.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Hard Rock Hotel under construction in New Orleans collapses...

Some pallets of blocks and some garbage bins should not be causing such a large scale progressive collapse.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (structuralengr89)

Check out the steel framing and deck orientation in the cantilever...where those small canti tubes supposed to hold the floor up? The shoring appears to fail, but this appears to be some weird, inadequate framing

I'd have to assume we're seeing incomplete structure here, shoring being a big clue of course. I mean, there is no good load path for those stub cantilever tubes - no back-span, only a small beam in torsion to resist the moment. There must have been some more steel that would eventually be installed to support the ends of the tube steel members...



RE: Hard Rock Hotel under construction in New Orleans collapses...

I won’t comment on this as it would be inappropriate to be connecting dots at this stage, but I wanted to share another news item I came across: Link



RE: Hard Rock Hotel under construction in New Orleans collapses...

Some construction progress videos: Link

RE: Hard Rock Hotel under construction in New Orleans collapses...

Do I see that overhang detail correctly? A W-flanged girder with periodic tube sections cantilevering out 6-10 feet without backspans to support a slab on metal deck?

If so, it would seem like a pretty flexible system. Did all the load just keeping going down the most-stiff path (temporary shores) until one finally buckled and set off the dominoes? It probably wouldn't take much for the bottom flange of the W-shaped girder to get "pushed in" when the cantilevers suddenly tried to engage and take the load.

"We shape our buildings, thereafter they shape us." -WSC

RE: Hard Rock Hotel under construction in New Orleans collapses...

Looking at the contractor's website and the structural engineering firm's website, neither seems to have a project anywhere near this height or scale in their portfolios.

RE: Hard Rock Hotel under construction in New Orleans collapses...

(OP)

Quote (bones206)


Some construction progress videos:

First off, let me say that this is what it looks like living in an era of drones.

Second, I can't believe that this company, Citadel Builders, have kept these Hard Rock videos up on their website. I would think that their corporate lawyers, to say nothing of their PR staff, would have immoderately ordered them taken down.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Hard Rock Hotel under construction in New Orleans collapses...

Some generic info displayed on Citadel's website - their plan room access to the drawings isn't active.


RE: Hard Rock Hotel under construction in New Orleans collapses...

Is it typical to offer financial incentives for early completion on a project such as this one?


RE: Hard Rock Hotel under construction in New Orleans collapses...

The structural engineer has a team of 2 engineers, an EIT, and 5 designers. Seems like a project the size of this would warrant a larger team of engineers. If the designers are truly designers and not just CAD people I could see that helping but a 17 story structure would keep an engineer and EIT busy for a significant amount of time.

For the record, this may have nothing to do with the design and might be a construction error. I just found it odd that such a large project had a structural engineer with such a small bench.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Not sure if those tubes in the picture are actually permanent structure or just shore beams to temporarily support the deck until the concrete reaches strength, perhaps the final intended end condition would match the lowest visible floor in the image posted by structuralengr89. The one flyover video post collapse appeared to show a good bit of reinf. steel in the concrete deck.

Rabbit12:
That's actually a decently large design team in my experience, similar job would be handled by a 3-4 person structural team if done by a number of the firms in my local.

Open Source Structural Applications: https://github.com/buddyd16/Structural-Engineering

RE: Hard Rock Hotel under construction in New Orleans collapses...

Agree those tubes are probably just shoring.

RE: Hard Rock Hotel under construction in New Orleans collapses...

If they were counting on the deck cantilevering over that (rather petite) beam, why would the deck change orientation? Why would such a detail be used to begin with? Maybe those tubes were to connect to part of a (structural?) curtain wall system? I wish we had a higher res picture of the tube-to-beam connections. And looking at how the tube on the column line is still oriented vertically, it seems that the tubes might not have any shear studs?

RE: Hard Rock Hotel under construction in New Orleans collapses...

Drawings seem to show a different edge detail:



RE: Hard Rock Hotel under construction in New Orleans collapses...

@Tomfh

There's an alternate floor plan. No details seem to be shown for this floor. Tubes are shown to be final structure.

RC


RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Tomfh)

Agree those tubes are probably just shoring.

I though so too, but the Permit structural drawings (S3.5A and B) show:



No backspan, and framed into a W10x19:

RE: Hard Rock Hotel under construction in New Orleans collapses...

Interesting that permit set drawing S3.5B is OPTION B for 16 & 17th floor framing:


RE: Hard Rock Hotel under construction in New Orleans collapses...

The deck spans in many locations (+/ 25 feet) seem quite excessive for a 3" composite deck (5.5" total slab thickness).

RE: Hard Rock Hotel under construction in New Orleans collapses...

How far does this decking normally span? What sort of span to depth ratio?

RE: Hard Rock Hotel under construction in New Orleans collapses...

So with that HSS outlooker detail you'd be relying on torsion in the beam and tension in the 4x4 WWF to resist the out-of-plane bending moment, correct? I sincerely hope this wasn't the intention.

However, looking at the rendering posted by dold, the cantilever on the 16th/17th level looks to be a balcony exposed to view from below. So the architect probably requested an alternative to the bent plate and gusset detail used on other levels to achieve the envisioned floating look.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Those spans for deck are way excessive, they can't be right but that is what those plans show.

TW

RE: Hard Rock Hotel under construction in New Orleans collapses...

I guess I take back my comment on "missing something" with the HSS members in that photo... yikes!

And my Verco catalog cuts the W3/5.5" concrete tables off at a 16'-0" span, although I'm sure maybe a couple more feet (under really light superimposed loadings) could be justified by calculation.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I sure hope these aren't the final drawings. Every floor beam on the 16th and 17th floors is a W10x19 outside of the elevator shafts.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Hopefully the column sizes on the upper levels were increased beyond W6x20s.

"We shape our buildings, thereafter they shape us." -WSC

RE: Hard Rock Hotel under construction in New Orleans collapses...

The final two spans (that collapsed in the video) are significantly shorter than the rest.

Maybe the failure cascaded thru the 25 foot spans as continuity was lost, and then stopped temporarily at the shorter spans.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Celt83, I presume the entire company can't work on this one project since I assume the firm also has other projects. The size of this project and the size of the structural engineering company seems a little disproportionate. I'm sure it's possible to complete with a small team like that but there are also other projects, marketing, etc. that must happen. I'm guessing this project really taxed that firm.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I think we should be mindful of where these plans just came from. The person who posted the file has only made one post since 2015, and this was it. I tried looking up that permit drawing set pdf on the NOLA website, and it did not come up in the search results. That tells me this file was posted by someone who has access to the drawings. Not sure what to make of that, but on the surface it appears to be a deliberate attempt to leak this info to the public. My apologize to carpoolturkey/johnsmith95 if I'm barking up the wrong tree here.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Surely that was not the final set. Its marked as a permit set and the project is listed as permit phase on the title block. But from just eyeballing it, the photos seem to reflect the member sizes on the plans. From my load tables the 3" 16ga composite deck caps out at 95 psf at an 18' span. I do not see it supporting a 70 psf load for a 26' span.

Am I reading plans right that one option for the cantilever was a huge plate and stiffeners, that doesn't seem very practical? I imagine the designer was counting on the kick backs shown in the section below to be installed with the tube option as well but there is no detail covering the tube cantilever option that i see. Either way it is a very light section to cantilever off of.


RE: Hard Rock Hotel under construction in New Orleans collapses...

Ok, sorry. It just raised a red flag when your handle suddenly changed to johnsmith95.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The stamped permit set shows no rebar in slab (4000 psf normal wt with fiber and mesh). No way that the deck guy (or an engineer paying attention) would do that, there has to be an explanation. Maybe you could put enough rebar to make it work on paper but that would be super outside the norm.

TW

RE: Hard Rock Hotel under construction in New Orleans collapses...

The drawing index in the ARCH_FULL_SET_5.1.2019 file indicates a few more structural drawings beyond what's in the permit set. There must be a later set of structural drawings not included on the NOLA directory.

RE: Hard Rock Hotel under construction in New Orleans collapses...

A couple of things bother me (sort of hinted at above):
1. Those "all around weld" symbols show the engineer doesn't know how to weld, or design welds. You don't do "all around" where the weld crosses the contact planes.
2. The kickers going up to the underside of the concrete-deck slab will induce vertical upward forces on the slab system - the WWF in the system is most likely laid directly on the deck as there is not chairing or top clear distance specified. That means the flexure in that 2 1/2" thick slab (orthogonal to the flutes) is bending essentially an unreinforced slab.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Rabbit12: Misunderstood your post if that is their entire staff agree that would taxing along with other work.

Seems the intent was for the tubes to cantilever based on the option B framing in the available permit set.

The deck spans do seem to be excessive in several areas, I keep looking in the notes to see if there is something for some kind of typical infill framing in bays.

There are also several columns with framing in one direction only, assume they are then relying on the deck to brace one axis of the column (not something I am used to seeing).
There likely is a construction or later set of drawings, don't see a single section cut on the plans in the available permit set in the steel levels.

Open Source Structural Applications: https://github.com/buddyd16/Structural-Engineering

RE: Hard Rock Hotel under construction in New Orleans collapses...

bones206 - you appear to be correct, I've pulled my posts, my intent was not to spread misinformation. If others think it's usual for discussion, they can post them again.

RE: Hard Rock Hotel under construction in New Orleans collapses...

carpoolturkey,
I wouldn't call it misinformation. Those were signed and sealed permit drawings posted on the NOLA website.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Photos from the NOLA website.


This is an area that collapsed. Deck shows reinforcing.



Reinforcing shown elsewhere too:

RE: Hard Rock Hotel under construction in New Orleans collapses...

After taking a good look at these drawings... What happened to peer reviews? Code review? This should have never happened.

Also the cranes appear to be Liebherr 316 EC-H. Specs on S1.4.

RE: Hard Rock Hotel under construction in New Orleans collapses...

4
This is going to be a PRIME EXAMPLE of Why Practice ACT Structural Engineering Licensure should be Mandatory in all 50 States.

Louisiana is a Title Act State...Previously if you passed the old SE I exam, your were licensed as a PE, but Structural was listed as your field of work.

I just checked the 2 guys listed on the SER's website on the Louisiana Board of Licensure...the Owner and the 2nd PE on Staff. They are both listed as "Civil"

THIS IS WHY EVERY STATE IN THE NATION SHOULD REQUIRE ANY BUILDING 3 STORIES ARE MORE TO BE STAMPED BY A SE WHO HAS PASSED THE 16 HOUR EXAM....AN NO GRANDFATHERING!!!!



RE: Hard Rock Hotel under construction in New Orleans collapses...

I apologize in advance because I am commenting before reading all the replies in this thread. I hope I am not repeating topics that have been settled one way or another.

(1) WIND. I was about 25 miles from the site of this collapse on Saturday morning, and I can tell you it was QUITE windy at the time of the collapse. A picnic table umbrella went airborne and almost hit someone at our Farmers' Market. Our tent was straining at its stakes, and at times we held it down by hand to make sure it didn't go airborne, too.

(2) FIRST CRASH. The man who took the best video heard clanking, took a second or two to pull over and stop his car, saw the corner sagging, and started the video. That may have taken 5-10 seconds. Did parts of the crane break first?

(3) SIMILAR SCHEME? Regardless of how sketchy the rectangular tubing (and associate shoring) looks, it's almost always the case that engineers repeat the basic design scheme on buildings like this, spans, direction of metal slab ribs, slab thickness, and rebar ratio. Each building is a unique design, but they wouldn't change anything radical from one building to the next, and they would have checked for reasonable agreement with previous designs. They build them in one city after another. So, the question becomes, was anything significantly different with this design?

(4) DROUGHT. Finally, this is New Orleans, and the soils are notoriously soft and still settling. We have almost been in a drought here. We had 0.17" of rain in all of September, and no rain to speak of since then. Just note that in case the wind caused some sort of problem for the support of the crane. Did the water table drop? Doesn't seem likely to have an effect, based on the mode of failure, but any unusual conditions are something to think about.

The video link posted by dold shows the man on the scaffolding without blurring (that portion has been blurred in the current version of the collapse video taken from downriver Rampart St).



RE: Hard Rock Hotel under construction in New Orleans collapses...

@NOLA

1. My money would be on "probably not wind" in this case.

2. Not enough info to say.

3. Perhaps this engineer did not have anybody else's go-by's to copy from on this one...

4. Bigger issues upstairs.

RE: Hard Rock Hotel under construction in New Orleans collapses...

(3) I rescind my comment (3) above, as I looked at the website for the structural engineer and it is a local firm that seems could not possibly have designed similar structures, as the firm has only two engineers, an EIT, and a few designers.

(1) I still think wind could have caused the crane to add stresses to the main structural system that were, perhaps, not fully planned for.

This makes my hands sweat and my heart race, like panic-mode, to see that tiny firm responsible for a complex project of this size.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I came here to post this link as an FYI, then got caught up in the latest discussion.

https://www.wwltv.com/article/news/investigations/...

I don't think the pool contributed to the collapse, as it was placed on the Canal St portion of the building which did not collapse. You can see the pool on the upper level of that part of the building in the drone footage from Sunday.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Something I noticed from structuralengr89 post of 13 Oct 19 16:59 (showing the photo of the buckled post-shores) immediately above, the W beam connection to the column shows a bolted flange connection BUT the web plate has no bolts installed, and no field weld is visible either.




I wonder if other beam/column connections had similar yet-to-be-installed bolts. The metal deck is already installed at this floor - and it unusual to delay bolt install after deck is installed.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The likely failure mode has to be torsion on those 25' long W10x19 girder, right?

As soon as those temporary shoring posts were removed (or started to buckle), that HSS6 cantilever + W10x19 girder system needed to take up the load from that 7' cantilever edge condition.

But how could it?

"We shape our buildings, thereafter they shape us." -WSC

RE: Hard Rock Hotel under construction in New Orleans collapses...

Celt83, no worries. For all I know maybe they have some contract engineers that work for them. Their team size might have nothing to do with this failure. I just found it a tad odd.

As far as your column comment. I was taught at the beginning of my career to also have framing coming into two orthogonal sides of a column at the top. Many times I have added a small W8x10 or something just to brace the column in one direction.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Rabbit12, I have likewise started to wonder if this small local firm has support from a bigger out-of-state firm. Or, even a bigger in-state firm. Haeslip used to work for a bigger firm in the same building as his current office.

RE: Hard Rock Hotel under construction in New Orleans collapses...

3
Just saying the words "W10x19 girder" inspires confidence.

What boggles my mind is how many hands this passed through and nobody said anything: Permit office, code review, STEEL FABRICATOR, steel deck supplier, GC, Architect, whoever designed the PT systems, inspectors, etc, etc, etc. AND NOT A SINGLE PERSON RAISED ANY QUESTIONS? (at least as far as we know at this point).

Deck supplier: "Hey generally we dont recommend spanning 3" composite deck TWENTY FIVE FEET, just wanted to make sure that was the intent."

Steel detailer: "Look, this isn't the first project we've worked on and some of this framing looks a little light. Is this HSS6x3 a typo? Because it is spanning 20 feet and supporting a W12 with about 200+ sq ft of trib...? And these 6x3 outriggers seem to be completely unsupported on one end, please clarify?"

If this is truly the final design for the floor and roof framing, it feels to me like somebody made a model in whatever software and no load got attributed to any of the framing. So the program just selected the lightest size to get span/depth ratio. Every single beam in thier depth class is the lightest shape (with some exceptions - W12x26, etc.). W21x44, W18x35, W16x26. But maybe not, because I can't find any rhyme or reason for some of these beam sizes.

Madness.

RE: Hard Rock Hotel under construction in New Orleans collapses...

If the drawing was a preliminary - I know that in Revit, many times we populate the framing with small size beams - simply as initial placeholders.
W10x19 beams are dinky little things and I suspect that these were just in there as an initial size only - pre-analysis.
I could be wrong but that is how we roll on a lot of projects.

If these were sealed plans, then I'm off base here, of course.

Where did you get all these plans? I don't see a link above. Was the link deleted?

RE: Hard Rock Hotel under construction in New Orleans collapses...

So what do you think will happen for failure like this? Can you use what's left? Abandon the idea and start fresh?

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (JohnRBaker)

Some construction progress videos:

First off, let me say that this is what it looks like living in an era of drones.

Second, I can't believe that this company, Citadel Builders, have kept these Hard Rock videos up on their website. I would think that their corporate lawyers, to say nothing of their PR staff, would have immoderately ordered them taken down.
It also shows them flying the drones in violation of FAA regulations, I doubt they received a waiver.

RE: Hard Rock Hotel under construction in New Orleans collapses...

>So what do you think will happen for failure like this? Can you use what's left? Abandon the idea and start fresh?

They will probably evaluate the existing design and if it is determined to be inadequate, attempt to create a new design to work on top of the existing transfer slab, since the pictures appear to show it still in good shape. Depending on the assumed loads for the current design, the new design may be able to use the existing column spacing, and may need to remove some of the planned upper floors if the slab wasn't designed for the loads calculated by the new analysis.

Or, if it is determined that the final design was adequate, but construction means and methods are at fault, they may be able to rebuild the current design. New safeguards or methods would need to be used to allow safe construction. That seems unlikely, given the comments in this thread. However, it may be possible that the full drawing set includes more information and details that would show the design to be adequate.

RE: Hard Rock Hotel under construction in New Orleans collapses...

JAE,

Someone posted the link but deleted it. It's a public website, not behind a login or anything, and these are effectively public records. Look for "HRH_1031_CANAL_STRUCTURAL_FULL_SET_6.8.2018....". These are SEALED permit drawings - nothing on the drawings saying 'not for construction', etc. You'll notice in some of the inspection pictures (see below) it looks like there were at least two revisions, at least to the foundation drawings...

For what it's worth, somebody could file a FOIA request with the city to get the final drawings. But each municipality has different rules for giving out drawings. I know in a lot of cities in California, if the documents have a professional's seal on it, one must obtain written consent via affidavit first from the owner of the building, and then typically the muni will make an attempt to get written approval from the professional who sealed the docs, before releasing the docs. Copyrights or something... I've never FOIA'd in NOLA though. Plus this is now tied up in an investigation i'm sure, so that might foul up the FOIA stuff for the time being.

https://onestopapp.nola.gov/Documents.aspx?ObjLabel=Permit&ID=462842


RE: Hard Rock Hotel under construction in New Orleans collapses...

Worse than that, the requester has to get written permission from the author of the drawings before release, and then pay the city to get the copies.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers Entire Forum list http://www.eng-tips.com/forumlist.cfm

RE: Hard Rock Hotel under construction in New Orleans collapses...

Although from a generic news station, I was surprised at the info in this video given the title was something about them installing the pool basin just a few hours before the collapse. To whit, I doubt this basin install had anything to do with it, but the video talks about the contractor's son being indicted for fraud earlier, etc. Might be worth a watch for 3 minutes...
https://www.youtube.com/watch?v=bgOF3NtAmU8

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

So what do you think will happen for failure like this? Can you use what's left? Abandon the idea and start fresh?

New buildings should not be built with parking garages, as self-driving cars will greatly reduce the need for parking within a decade or so and the preference for Uber-ing to the Quarter means there are fewer parkers there for day trips now. If only there was a secure "Park and Ride" with a shuttle service for overnight guests, we could eliminate all of that ugly, wasted parking space in the Quarter and surrounding areas. In the meantime, though, I know that parking garages are a great revenue generator, with nearly 100% occupancy, even when the retail spaces struggle for stores and shoppers. Who shops at retail today?

And,

Quote:

Although from a generic news station...
Generic news station? That's from WWL-TV in New Orleans.

RE: Hard Rock Hotel under construction in New Orleans collapses...

OK - looking at the framing plan there is an oddity in it - not sure if it could be considered a cause, at all, of the collapse.
But running down the length of the building - right at the interface between the remaining structure and the collapsed structure is a long corridor made up only of the deck-slab.
This deck slab is rotated 90 degrees from all the other deck slabs in the building.
What's more, there are NO structural steel beams crossing this long corridor at all.
I would never do this. I always want to connect my steel throughout a frame and not rely on 2 1/2" of WWF reinforced concrete to hold the structure together.

RE: Hard Rock Hotel under construction in New Orleans collapses...

JAE, could that strip of decking have acted as a fuse that prevented the remainder of the building from collapsing?

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Structural engineer involved in early design work)

"The one thing I find hard to understand is the collapse started at the rear of the building (by Rampart and Iberville streets) but it wound up, you had collapsed slabs all the way on the front end of the build which is 300 feet away (on Canal Street)," he said. "So I don’t know how that progression worked like that. I guess that’s part of what the investigation is going to reveal.”
Link

If the building was essentially perforated down the middle by that strip of decking without framing, that could possibly explain how the collapse seemed to wrap around the front from one end to the other without pulling down the rest of the building with it.


RE: Hard Rock Hotel under construction in New Orleans collapses...

Yes that is most likely true.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The collapsed area JAE highlighted had a series of W16x26 transfer girders at the 15th floor supporting the W6x20 columns above (which support 3 additional levels).

RE: Hard Rock Hotel under construction in New Orleans collapses...



Dold...You get a star for your W10x19 girder comment!

Let's hope those plans you linked which are sealed and do not state NFC are not what was used for construction!!!

RE: Hard Rock Hotel under construction in New Orleans collapses...

These drawings are a mess they have a HSS6x3x3/8" girder supporting a W21x444, grid F and 31 15th level. Along with grid 39 PP to YY

They are stamped and signed with permit set document stamp on them.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (NOLAscience)

Rabbit12, I have likewise started to wonder if this small local firm has support from a bigger out-of-state firm. Or, even a bigger in-state firm. Haeslip used to work for a bigger firm in the same building as his current office.

I'd be more critical of the qualifications and capabilities than the size of the firm. A firm that size should have no problem with a job like this if they know what they're doing. I have personally seen one or two man shops crank out designs larger and more complex than this. But those one or two guys knew their stuff.

RE: Hard Rock Hotel under construction in New Orleans collapses...

3
I think it is a waste of time here to talk about the size of their firm - agree 100% with MrHershey.
In fact I get a bit tired when there is a common perceived (but wrong) thought that only large firms can do large structural projects.

The key is the actual qualifications of the engineers, not the number of minions surrounding them.

RE: Hard Rock Hotel under construction in New Orleans collapses...

5
I think everyone should put down the knives for a bit. There are some bad errors in these drawings and details that most wouldn't do e.g. W6 columns (would be better off using a tube section), small HSS girders, excessive deck spans, etc. But let's not act like we're putting out perfect drawings on a daily. Let's hope some of these "assumed" and real errors were caught in submittal stage or at least that the numbers actually work out even if the constructabiliy doesn't make sense. It could be your name in the news next, let's give them the benefit of doubt until gross negligence is proven.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Agree spieng. This pile on is a bit distasteful. As are the comments that only big firms can do 10 storey buildings.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (JAE)

I know that in Revit, many times we populate the framing with small size beams - simply as initial placeholders.

We do this too. I don’t like the practice at all.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Tomfh)

We do this too. I don’t like the practice at all.

Maybe just use like W36x330 so the GC will blow a gasket during pricing to bring it to your attention instead of trying to build 10 floors out of W10 beams/girders and W6 columns. :D

RC


RE: Hard Rock Hotel under construction in New Orleans collapses...

3
Hmmm. I didn’t see any knives - only comments pertaining to sealed and signed drawings based on our engineering knowledge and experience. No one here is or has persecuted the EOR or claimed to know why this building fell down.

This forum and threads like this are open to discussions about failures so we all can learn from mistakes... be they our mistakes or others.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I agree JAE. I don't think anyone has placed the blame on the EOR or the contractor.

I think everyone agrees the permit plans sure raise a lot of questions about the design. The question is whether there was significant changes from permit to IFC drawings.

RE: Hard Rock Hotel under construction in New Orleans collapses...

As structural engineers, a building collapse is our worst nightmare. When it happens, we all want to know why. When we have access to a signed and sealed set of drawings for the structure, I think it is perfectly acceptable to discuss them.
These were sealed permit drawings. When I submit a set of signed and sealed drawings for permit, the building official has every right to believe they are complete drawings that the building can be constructed with. These drawings raise a lot of red flags and I keep hoping there was a revised set, but in the end, the building collapsed and we should all try to learn from it.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I have heard the Hyatt Regency collapse in Ethics Seminars over the years so many times, that I literally cringe when I hear a speaker bring it up. Mark my words, this will be the new Hyatt Ethics Seminar.

My hope is that somehow NCSEA and state MOs will use this to push state legislative bodies to adopt SE Practice Act requirements for structures that if designed improperly can do the public great harm.

I do not know the SER personally and he might be a great engineer. But the LA board of engineers lists his discipline (as indicated on his stamp) as CIVIL. I am a Louisiana licensed Professional Engineer with Disciplines of CIVIL and STRUCTURAL. I had to pass the 16 hr SE exam to get the Structural designation in LA.

But the Structural designation in LA means nothing...It is a title act state. Again, I do not know this guy and he may be an outstanding engineer. Maybe one of his EIT's designed it , put his Seal on it without his knowledge and submitted it to the city....but don't you think that a guy designing a 18 story building should at least have passed the 16 HR SE Exam?...which is just a minimum level of competence?


RE: Hard Rock Hotel under construction in New Orleans collapses...

I keep thinking about what a slow, cautious, and dangerous process it's going to be to clean that up. Will they drop the whole thing and start over? Or, try to remove all the debris and continue? Probably depends on what the drawings show.

Meanwhile, everything around that place is now in limbo and off-limits.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

My hope is that somehow NCSEA and state MOs will use this to push state legislative bodies to adopt SE Practice Act requirements for structures that if designed improperly can do the public great harm.

We have no way of knowing whether the collapse is even the fault of the EOR, so calls for changes to the state licensing requirement is a bit premature. It may be that the engineer is a terrific structural engineer, even though his stamp reads "Civil". There was no Structural Engineering test or licensing in this state when I passed the Civil Engineering exam in the 1990s.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

I keep thinking about what a slow, cautious, and dangerous process it's going to be to clean that up. Will they drop the whole thing and start over? Or, try to remove all the debris and continue? Probably depends on what the drawings show.

Meanwhile, everything around that place is now in limbo and off-limits.

Displaced tourists at the hostel next door: https://www.wwltv.com/article/news/local/100-touri...



RE: Hard Rock Hotel under construction in New Orleans collapses...

I agree that it is not be the size of the firm that indicates the quality of the work, but look at the EOR's Facebook page and see the scope of their other projects and ask yourself if you would hire them to build a 17-story building in a tight CBD area. Just seems out of scale.

https://www.facebook.com/heaslipeng/?__tn__=%2Cd%2...

Hope the link works for you.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Have we discussed the unusual framing in this portion of the structural drawings from 2018? I hope this was revised in the review process.

And let's not forget that this strange building was the creation of the architect. The structural engineer was simply trying to support the architect's beams and floors against the force of gravity.

RE: Hard Rock Hotel under construction in New Orleans collapses...

In looking at several of the photos on the NOLA site, it appears they used a Versa-Deck dovetail composite deck. If properly reinforced and shored during construction it can span 25+ feet.

RE: Hard Rock Hotel under construction in New Orleans collapses...

This is borderline doxxing by a bunch of junior detectives with limited evidence. Please tread lightly. Peoples lives and livelihoods are at stake.

RE: Hard Rock Hotel under construction in New Orleans collapses...

As JAE has pointed out, the corridor didnt have beams tying the steelwork on either side.
From looking at the layout drawings there are 3 steel braced cores all of which are on 1 side of the corridor, with no cores in the area that collapsed.
Obviously we dont yet know what triggered the collapse, but once something started, the lack of any tying back to a core around the perimeter (other than the metal deck slab) would explain the disproportionate collapse.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (MTNClimber)

This is borderline doxxing by a bunch of junior detectives with limited evidence. Please tread lightly. Peoples lives and livelihoods are at stake.

JAE pointed out what the point of this thread is earlier and it is absolutely fair that we hold each other accountable as engineers. We will wait to see what the investigation reveals but in reviewing available information - SIGNED AND SEALED PERMIT DRAWINGS - we have found many instances that raise an eyebrow. Many items that make you say "well it probably COULD have been done that way, but should it have been?"

When the bar continuously gets lowered and things are done simply because they can be, even when they shouldn't be, simply to meet unrealistic demands, we all suffer. Who knows if that is the case here, but looking at the available information it sure seems like there were a lot of corners cut. As has been said many times already in the thread, hopefully a revised set exists that cleans up a lot of these concerns...

I think most of the comments here are strictly related to the design itself. Yes there are a few pushing for changes and commenting on the designer as an individual and I think that is misguided with where we are in the process.

RC


RE: Hard Rock Hotel under construction in New Orleans collapses...

3
So you would say you have enough evidence to start calling out people's full name and their online accounts? What's the point? I understand the desire to know what went wrong, but not to start doxxing people based on "SIGNED AND SEALED PERMIT DRAWINGS". You don't have any of the RFI responses, general correspondence, or access to what the contractors did wrong (if anything). I'm not a mod but I'm asking some people here to reel it in a bit and be more professional as this is a very serious event and doxxing could lead to serious actions.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (RCinVA)

As has been said many times already in the thread, hopefully a revised set exists that cleans up a lot of these concerns...
I think most of the comments here are strictly related to the design itself. Yes there are a few pushing for changes and commenting on the designer as an individual and I think that is misguided with where we are in the process.

I did not see the linkedin profile link prior to this and think that is not helpful but I think my comment here agrees with your general sentiment. I'm only interested in commenting on the design.

RC


RE: Hard Rock Hotel under construction in New Orleans collapses...

JAE - sealed and signed does not equate to perfect or without error. It's okay to critique the drawings, but some of the comments are dangling on the edge of arrogance. The comment was for the benefit of all to remember, you're only one mistake away from scrutiny.

RE: Hard Rock Hotel under construction in New Orleans collapses...

2
I am not commenting on what we should or should not be discussing on this forum, but is it really doxxing if all of the information being discussed is easily accessible to the public? There has been no hacking of e-mail, release of files by a rouge employee, releasing of personal information such as addresses, etc.

In terms of the release of revised drawings, RFI's responses, mark-ups on shop drawings, etc. Those likely exist. My one comment on this is as follow:

Issuing a signed and sealed set of documents to anyone is an indication of a final design. This is not a promise to "clean it up later". In fact, the following statement is on the documents

"These plans and specifications have been prepared by me or under my close personal supervision and to the best of my knowledge and belief they comply with all city, state and federal requirements and I am not providing contract administration" followed with the verbiage stating "Certified Correct".

While I really hope that what we have seen is not what was final and being used for construction, one must question the design represented in the signed and sealed permit set.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I'm not suggesting that things need to be perfect.
No one here is.
And doxing someone's LinkedIn site is probably going too far, I'd agree.

Yes, if I design a structure that fails then I'm also in the hot seat, which...is...how...it...should...be.

Keep in mind that our entire profession has historically been largely based on self-policing, self-reporting, etc.
So studying, analyzing, and commenting on the public signed plans is not something to avoid, but to embrace.

It is our responsibility as engineers to protect the public welfare and safety.
In this case safety was severely compromised and it is totally appropriate for other engineers to study, learn, and gain insight into what happened and why.




RE: Hard Rock Hotel under construction in New Orleans collapses...

Yes it is still doxxing if something wasn't hacked. Even if it is public information its not warranted on this forum. We all want to know what went wrong. Calling out companies or public entities involved is fair, but not their personnel. Their name or LinkedIn account adds nothing to this discussion and only provides any avenue for someone else to falsely accuse someone of wrong doing. The news already does a good job of ruining innocent people's lives. We don't need to add to it.

Edit: JAE and others - I'm not saying everyone here shouldn't be looking at the evidence that's available. I'm just saying don't make this personal by dragging team members names and online accounts with photos into it.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Where I am at, it's common at the time of permit submittal we also supply a complete signed set of calculations. On the last project I completed I don't know how well the reviewer went through the calcs but I know he looked at them because he commented on how well they were put together. In fact on that particular project the plan reviewer wanted 100% PEMB drawings and calculations before they would issue the permit. I don't think this particular reviewer would have approved a plan set like the one for the Hard Rock.

For the most part plan reviewers check for IBC code compliance for occupancy, egress, fire protection and similar items and that's about it. Any sort of structural review is probably rare because the reviewers just have no clue what they are looking at. However, wouldn't it be a benefit that a reviewer can have at least enough knowledge to identify things that may be out of the ordinary and at least verify they are backed up by a calculation? Maybe that's opening Pandora's box and is an awful idea.

RE: Hard Rock Hotel under construction in New Orleans collapses...

IRstuff, you make a valid point, let's leave names and links out of it. That information is easy enough to find, if you are so inclined.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (MTNClimber)

This is borderline doxxing by a bunch of junior detectives with limited evidence. Please tread lightly. Peoples lives and livelihoods are at stake.

I agree with the doxxing sentiment. Since the formal investigation is ongoing, I think it would be best to keep names out of the discussion as much as possible. We can still talk through this using generic terms like contractor, engineer or inspector, without publishing their names ourselves. Anyone can readily look up the names on their own.

However, I don't see a problem with pointing out potential red flags if they may have relevance. I posted a link early on in this thread regarding New Orleans building officials who are currently subjects of a federal corruption investigation. Corruption and/or lack of inspection or thorough plan review could easily have played a role in all this, so it's a relevant data point to present. But I presented it with a disclaimer making it clear that it's just an isolated data point and it's too early to connect those dots. I didn't publish anyone's name.

It's a fine line and agree that we should strive to discuss what happened with due respect to those caught up in this tragedy. Disasters like this are usually multi-factorial and could very well be a series of lapses by several individuals that lead to a "perfect storm" scenario. So I think it's fair to examine anything that we think may be relevant, because you never know if something seemingly insignificant could turn out to be a contributing factor. But let's try to avoid being prematurely punitive by publishing names in a way that implies culpability. The internet never forgets.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (spieng89)

JAE - sealed and signed does not equate to perfect or without error. It's okay to critique the drawings, but some of the comments are dangling on the edge of arrogance. The comment was for the benefit of all to remember, you're only one mistake away from scrutiny.
If you are turning in a plan check submittal set which does not have a complete gravity or lateral system and will be correcting it later then you are bound to have a building collapse. These are not minor gaps to be filled in later we are not talking about soffit connections, custom connection details, etc. we are seeing gaps in basic engineering. Also these issues are never one mistake but mistakes made down the line. If one mistake was the issue building failures would so frequent as to be the norm and also be easily corrected. Dismissing criticism of these drawings because every project has an RFI for something missing is weak to say the least.

Doxxing is releasing private information to identify an individuals. Peoples public website, LinkedIn, etc. are not private. With that said the only person responsible is the EOR, the errors may have been done by a staff engineer or EIT. However, you sign the drawings you own any issues that come from the design.

RE: Hard Rock Hotel under construction in New Orleans collapses...

That may be your opinion about doxxing, but Wikipedia and others define it thusly:

Quote:

Doxing or doxxing (from dox, abbreviation of documents) is the Internet-based practice of researching and broadcasting private or identifying information (especially personally identifying information) about an individual or organization.
The methods employed to acquire this information include searching publicly available databases and social media websites (like Facebook), hacking, and social engineering. It is closely related to Internet vigilantism and hacktivism.
Yes, public information is public, but there's no need here to publish anyone's name or profile, since this is about the engineering and not the person. That's for the actual investigators to determine the relevance.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! https://www.youtube.com/watch?v=BKorP55Aqvg
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RE: Hard Rock Hotel under construction in New Orleans collapses...

3

Quote (Herbert Hoover)

“Engineering is a great profession. There is the fascination of watching a figment of the imagination emerge through the aid of science to a plan on paper. Then it moves to realization in stone or metal or energy. Then it brings jobs and homes to men. Then it elevates the standards of living and adds to the comforts of life. That is the engineer’s high privilege.

The great liability of the engineer compared to men of other professions is that his works are out in the open where all can see them. His acts, step by step, are in hard substance. He cannot bury his mistakes in the grave like the doctors. He cannot argue them into thin air or blame the judge like the lawyers. He cannot, like the architects, cover his failures with trees and vines. He cannot, like the politicians, screen his shortcomings by blaming his opponents and hope the people will forget. The engineer simply cannot deny he did it. If his works do not work, he is damned…

On the other hand, unlike the doctor his is not a life among the weak. Unlike the soldier, destruction is not his purpose. Unlike the lawyer, quarrels are not his daily bread. To the engineer falls the job of clothing the bare bones of science with life, comfort, and hope. No doubt as years go by the people forget which engineer did it, even if they ever knew. Or some politician puts his name on it. Or they credit it to some promoter who used other people’s money . . . But the engineer himself looks back at the unending stream of goodness which flows from his successes with satisfactions that few professions may know. And the verdict of his fellow professionals is all the accolade he wants.”

It is the duty of all engineers to review, discussion, dissect and nitpick failures. We need to understand them. Every student needs the story drummed into them. It's the only way we move collectively forward.

I really feel for the design team (and construction team, review team, code team, area businesses, workers families, etc.) - but the work is in the open for all to see. And it didn't work.

So let's discuss why.

"We shape our buildings, thereafter they shape us." -WSC

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Contractor from article)

“What it shows is that the concrete deck has so much deflection that they can’t remove the shore posts,” [The contractor interviewed in the article] said. “They have so much load on them, it’s bending them.” [The contractor interviewed in the article] said he’s been told workers had been removing the temporary posts, and “when they got to less and less of them, got more and more load on ‘em,” they tried to tell the contractor to stop but were told to keep going.

RE: Hard Rock Hotel under construction in New Orleans collapses...

2
Looking at the video, it's hard to see the sag in the deck as the video looks like it was filmed on a potato. But, the bent shoring post is clearly visible and it seems to be bent at a point higher than what one would think likely if it was hit by some piece of equipment.

Notice that at the 1:00 to 1:05 mark on the video, it looks like the corridor framing where there is left-to-right deck span and no beams crossing as JAE pointed out yesterday. This would seem to indicate it is the same building despite the GC's spokesman in the article questioning the video's provenance.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Oh my goodness...Even the guys out in the field know a W10x19 is a "Shit Beam"

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

Yes it is still doxxing if something wasn't hacked. Even if it is public information its not warranted on this forum. We all want to know what went wrong. Calling out companies or public entities involved is fair, but not their personnel.

It does make me shake my head to see that the building inspector had a master's in Urban Studies and a bachelor's in architecture, so I am thankful to the person who posted the link to the resumé of the plan reviewer. No one is blaming him, and I am not even ready to blame any profession or craftsman on the job. It's just more data.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Ok, on to a new subject. Could we get some comments from those of you who use REVIT regarding what the model would return for that strange framing on Floors 15 or so (Col Rows E-H and 1-6, from the image I shared above) near the Canal/Rampart corner (and the same at the Iberville/Rampart corner)? Even if a W10x19 were used in the model, why didn't the model show failure at that area?

I calculate mostly by hand or with very small models, so I don't know much about REVIT beyond some PDH training a year or so ago.

And this was the engineering company's 10th structural design in REVIT! You can do your own search to see the size and scale of their other recent designs.

From Facebook: "REVIT Model and completion of Ochsner Lake Terrace. Heaslip Engineering has hit TEN completed structural designs in Revit!"

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (NOLAscience)

Ok, on to a new subject. Could we get some comments from those of you who use REVIT regarding what the model would return for that strange framing on Floors 15 or so (Col Rows E-H and 1-6, from the image I shared above) near the Canal/Rampart corner (and the same at the Iberville/Rampart corner)? Even if a W10x19 were used in the model, why didn't the model show failure at that area?

I calculate mostly by hand or with very small models, so I don't know much about REVIT beyond some PDH training a year or so ago.

Despite what Autodesk may claim or portray, most engineering firms are doing zero analysis or design in Revit. Revit is typically used for drawing production and building 3D models to detect conflicts between design trades and that's it.

It CAN do analysis and design, but I don't think I've run into a single design firm yet that actually uses it for that. All of the analysis is done in a separate application and then those results are imported or translated over to Revit.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (StrucDesignEIT)

Looking at the video, it's hard to see the sag in the deck as the video looks like it was filmed on a potato. But, the bent shoring post is clearly visible and it seems to be bent at a point higher than what one would think likely if it was hit by some piece of equipment.

Notice that at the 1:00 to 1:05 mark on the video, it looks like the corridor framing where there is left-to-right deck span and no beams crossing as JAE pointed out yesterday. This would seem to indicate it is the same building despite the GC's spokesman in the article questioning the video's provenance

I love it: "filmed on a potato"!

That corridor is certainly a strange entity. Kills all continuity of the framing. In the collapse, I agree with 'bones206', who noted that the corridor acted like a "fuse" to prevent collapse of the entire building above the parking garage podium level.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

It CAN do analysis and design, but I don't think I've run into a single design firm yet that actually uses it for that. All of the analysis is done in a separate application and then those results are imported or translated over to Revit.

Ok, agreed. I remember that model importing from the PDH training now. So why didn't the separate application catch the problem (if, indeed, it is a problem) before importing or translating into REVIT?

RE: Hard Rock Hotel under construction in New Orleans collapses...

I'm still going back to the transfer girders at level 15. The W16x26 beams support W6x20 columns above, which support 3 additional levels above.
These W16x26 beams frame into W18x35 beams (Grid JJ between 4 and 9 for example). This beam is the same size on the floor below,which doesn't have these transfer loads.

It is very confusing because the W6 columns aren't shown on the 15th floor framing plan, but on the next sheet labeled 16th floor - roof column plan.



RE: Hard Rock Hotel under construction in New Orleans collapses...

REVIT is BIM modeling...It is typically not used in the US for structural analysis...it has replaced CAD for providing Construction Documents...I would guess that in Louisiana most designers would be using Bentley's Ram Structural System for analysis.

During the initial stages of the design, some designers might place a holder beam in the model until the Engineer determines the size.

RE: Hard Rock Hotel under construction in New Orleans collapses...

So why didn't the separate application catch the problem (if, indeed, it is a problem) before importing or translating into REVIT?

It not the job of the computer program to "CATCH THE PROBLEM". It is the job of the engineer to know what he is doing.


How about some basic span to depth ratios for Steel Girders and Joists that I was taught the first month of beginning my career in building design???

A W10 Girder spanning almost 30'??? Any structural engineer who has spent anytime analyzing beams know this will be a problem with excessive deflection and likely your connection detail.

I rarely use W10s because I can't get enough bolts in them.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (NOLAscience (Structural))

Ok, agreed. I remember that model importing from the PDH training now. So why didn't the separate application catch the problem (if, indeed, it is a problem) before importing or translating into REVIT?

Because there are a lot of firms that, like mine, just brute force the model (i.e., build it within REVIT from the ground up). We use RISA, and while there is a RISA-REVIT link, by the time I've sorted out all the node and floor level issues, I find that it's just as fast to model it directly. EDIT TO ADD: and so, when the design finally gets done, you have to go back into the model and update all the members. Whatever analysis program should have alerted the designer to any issues.

Unrelated to the REVIT, from Table 3-6 in the 15th edition, Max uniform loading (ASD) on a 17' W10x19 is only 1,294 plf (assumes laterally braced to develop Mp - about 3'). With a trib width of 25', that leaves max D+L floor load of 51.8 psf. (Note: see structuralengr89's post with the semi-close up of the framing. The 17' long beam w/25' trib width is on MM.7) That's what I get for not downloading the plans. (See below, beams are supposed to be composite)

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (winelandy)

Unrelated to the REVIT, from Table 3-6 in the 15th edition, Max uniform loading (ASD) on a 17' W10x19 is only 1,294 plf (assumes laterally braced to develop Mp - about 3'). With a trib width of 25', that leaves max D+L floor load of 51.8 psf. (Note: see structuralengr89's post with the semi-close up of the framing. The 17' long beam w/25' trib width is on MM.7)

These are composite beams, so Table 3-6 doesn't apply.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (IceNine)

These are composite beams, so Table 3-6 doesn't apply.

Correct. I was just going to point that out. I know when we've specified composite beams we always put W18x35[XX] or something after the member size with the [XX] indicating number of studs.

I see on this plan there is just a generic table for studs at a specific spacing depending on their length.

I can't say I've ever seen this for composite construction at least in the DC/MD/VA area.

RC


RE: Hard Rock Hotel under construction in New Orleans collapses...

Winelady,
The deck is not spanning in the direction shown on the plans...its spanning in the other direction driving all the load to the perimeter W10x19...Try W10x19 spanning 25'-9" with 24' of trib.




RE: Hard Rock Hotel under construction in New Orleans collapses...

That's uh, WinelandV (not a Y)...

At any rate, that's a pretty big change from the plans, or it's a pretty massive miss by the contractor.

RE: Hard Rock Hotel under construction in New Orleans collapses...

IceNine/Winelandv: yeah table 3.6 wouldn't apply to the composite phase D+L but it can be used in the pre-composite phase and 51 psf is about the self weight of the deck listed in my Vulcraft catalog. As already stated though it may be likely that these were place holder beams in the drafting and got corrected in later set.

structuralengr89:
Edit: I believe you are correct for the lower levels,Roof level doesn't appear to have a deck span callout. The area in the plan screenshot in your post appears to be the collapsed deck which looks to have the ribs in the same direction as on the plan though.

Open Source Structural Applications: https://github.com/buddyd16/Structural-Engineering

RE: Hard Rock Hotel under construction in New Orleans collapses...

Sorry Winelady!

RE: Hard Rock Hotel under construction in New Orleans collapses...

Has anyone noticed that the tables for beam to column connections on sheet S3.14 don't show column sizes smaller than W10x49. I wonder what is going on with the W10x19 beam to W6x20 column connections? Everything else seems to be called out in the tables. I also don't see any beams listed as smaller than W12x26. Maybe this was left to the fabricator's engineer to design connections? Notes on S1.0A seem to indicate delegated connection design.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Celt83)

IceNine/Winelandv: yeah table 3.6 wouldn't apply to the composite phase D+L but it can be used in the pre-composite phase and 51 psf is about the self weight of the deck listed in my Vulcraft catalog. As already stated they it may be likely that these were place holder beams in the drafting and got corrected in later set.

Unless this was meant to be a shored composite design. In the video posted above, the contractors are removing shores.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Strucutral89: the decking orientation changes direction in plan in places, including at corners.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (IceNine)

Unless this was meant to be a shored composite design. In the video posted above, the contractors are removing shores.

solid catch.. I missed that.

Open Source Structural Applications: https://github.com/buddyd16/Structural-Engineering

RE: Hard Rock Hotel under construction in New Orleans collapses...

Thanks Celt83 for the correction.

RE: Hard Rock Hotel under construction in New Orleans collapses...




I hope the guy in the yellow vest in the lower right hand corner is getting paid well to stand in that location.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Yeah, he's definitely standing bow-legged

RE: Hard Rock Hotel under construction in New Orleans collapses...

If the allegation in the article is true that the safety issue was raised by workers but dismissed by someone in a management/oversight position, that's almost worse than a design error. I really hope it didn't play out like that.

That video from the worker is truly chilling. Honestly harder to watch than the video of the actual collapse. It's evident the man in the video understood the imminent peril of the situation, you could hear it in his voice. The way he trailed off and said almost solemnly, "Muy grave, Papa" at the end is just so haunting. It sounded like a man resigned to fate with no recourse for his concerns.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Have a look at this video around 1:00-1:05. Granted, there is now a tremendous load on those columns due to the 2 floors of slab still hanging off the right side. But good heavens look at the deflection of that beam with the two columns on top. Furthermore, observe how the deck on the 14th floor is just totally gutted all the way back to grid 32.

Also tagged up some numbers on the floors. The 'transfer floor' is the 16th floor. Using the elevator frame elevations as reference. Speaking of which, what happened to all the braced frames? I see none in the pics and vids? Nixed in later revision?


Deck rippage:



Floor count:



Transfer 'girder' deflection:


RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (dold)

Speaking of which, what happened to all the braced frames? I see none in the pics and vids? Nixed in later revision?

I've been thinking about that, too. It seems like a major design change to go from the steel frames for the elevator towers on Dwg S3-10 to the concrete as shown in photos such as this one.



The photo also shows the crane placed in an opening in one of the parking levels. I am looking for a photo of the crane opening at one the upper levels, but I haven't found one yet.



RE: Hard Rock Hotel under construction in New Orleans collapses...

Many good lessons for Engineers on this failure:

1. Designated Connection Design. Do you designate others to design the connections on your projects? Guess what, if it fails you will be sued. In fact, everyone on the project team gets sued - architect, contractor, structural, electrical, landscape arch...if you have insurance you are getting sued.

2. Requiring the Contractor to shore your beams. I checked some of the W10x19 in Ram Structure Composite..and the EOR must have used shored beam design. Are you relying on the Contractor to shore your red iron during construction? No way I would allow this.

3. Having beams with proper span to depth ratios. I would never use a W10 for a girder. The fly over video shows some remaining with 2 bolt double angle connections. After the flanges are coped, how much web do you have left? And then you leave that to someone else to design?

My guess for the failure was excessive deflection for both red iron and decking as witnessed by the immigrant worker's video...additional dead load that was not accounted for...followed by ripping of connection.


RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (NOLAscience)

I've been thinking about that, too. It seems like a major design change to go from the steel frames for the elevator towers on Dwg S3-10 to the concrete as shown in photos such as this one.

The drawings show concrete shear walls below level 8 and steel braced frames above level 8.
It appears they switched to moment frames rather than braced frames.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I have a couple of comments about the shoring.

1. In the construction worker's video, it shows a shore post that is buckled and tight to the composite deck. Typically, you would expect that the shore post would have a distribution beam that would provide support to all of the low ribs of the deck, and not just a single point. Now, I guess this could be re-shoring, and a post is located directly above, but that does not make sense from a construction sequencing. Since this is composite deck, there is no need to strip forms. It would make no sense to remove the beams, from a labor perspective.

2. I worked as a laborer for a GC while in college. While we did not do anything of this scale, we did do a few suspended slabs with shored construction. Once the concrete had cured, and it was time to removed the forming and shoring, we would do it in a very methodical method. We would lower the shoring by turning the screw jack 1/4 turn at a time on all of the shore posts, so that we would let the permanent structure pick up the load slowly and more uniformly. This also would prevent accidental stress reversals and large point loads. In watching the video and reading the interpretations, it appears (one cannot be sure) that the method was to remove posts completely. If this is the case, you could get all sorts of bizarre stresses, especially in a structure that appears to be as flexible as this one.

I still have numerous questions and concerns on the structural design, but shoring design and installation needs to be examined closely as well. One would think, that on a project of this scale, shoring design submittals would have been submitted to for review by the SEOR. This would be especially important if the design was to utilize shored composite construction.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Yeah that buckled post is odd. It looks abandoned. I’ve seen that happen when props buckle. The contractors bail and raise the alarm.

RE: Hard Rock Hotel under construction in New Orleans collapses...

NOLA, those are still the PT levels. PT from foundation to level 8 which was the 36" transfer slab. The steel framed cores above were a mix of braces and moment frames according to the 6.8.2018 drawings, starting at level 8.

On a similar note. I wonder if they actually used the 'typical column to embed detail' on s3.13 for the corewall (frame) columns.

And speaking of embeds, S2.19 - are these supposed to be moment connections? If so, why? To give fixity and reduce beam sizes? Surely not for any sort of lateral stability since these are at mezzanine level, even though I dont see any w18x35 or w24x55 on the mezz plan. Maybe some more insight on the "yea there are typos, we'll go fix them later" situation? Not sure I understand the welding scheme on these connections either. Also I'm really digging how every detail that shows a headed stud calls for 3/16 all around fillet, yet the gen notes for steel deck state that studs are to be gun welded and mentions ferrules, etc. So, whoever wrote the notes at least knew the basics of headed studs. Granted, I'm not the biggest fan of stud gun welds - I've witnessed studs literally fall off of embeds when i was moving them out of the crates on site one time. The entire batch. Drop an embed on the dirt and PING, down to 3 studs. But...imagine the fab time for the 5k embeds

RE: Hard Rock Hotel under construction in New Orleans collapses...

What type of collapse would this be officially referred to as?
I'm used to seeing damage from collapses caused by external forces such as natural disasters. But seeing these 'seemingly' random collapses like the pedestrian bridge at the Florida university is quite disturbing.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Sorry for my error on the elevator core. People kept interrupting me (with real work questions!) while I was looking through videos for photos and searching the drawing PDFs. The PDFs got hung up every now and then, too, which added to the discontinuity.

As for this,

Quote (Kreemerz)

What type of collapse would this be officially referred to as?
I'm used to seeing damage from collapses caused by external forces such as natural disasters. But seeing these 'seemingly' random collapses like the pedestrian bridge at the Florida university is quite disturbing.

We are supposed to design structures to resist "natural forces", though we are given a pass when truly unforeseeable events occur (e.g., an earthquake in an area not known to be subjected to seismic activity and where the building codes do not require seismic resistance). Usually after a disaster such as this one, building codes are updated to reflect something like a new design condition to be checked.

"Random collapse"? It's not random. We will find the cause for both of these collapses. Usually, the failure is caused by a combination of factors, such as (1) design decisions, (2) construction practices or variances, as well as (3) environmental conditions (perhaps unanticipated conditions). This is not "random", and we learn from each failure.

And, yes, I know that "random" has a different meaning for those of us who are scientists and statisticians as compared to teenagers and 20-somethings.

<<random
1.
made, done, happening, or chosen without method or conscious decision.
"a random sample of 100 households"
STATISTICS
governed by or involving equal chances for each item.

2.
INFORMAL•DEROGATORY
unfamiliar or unspecified.
"are you going to take some random guy on Twitter's word?"
INFORMAL
odd, unusual, or unexpected.
"the class was hard but he was so random that it was always fun" >>

RE: Hard Rock Hotel under construction in New Orleans collapses...

Almost invariably, failures such as this are ultimately caused by human error or human malfeasance. If loading was incorrectly analyzed or missed or ignored or materials were incorrectly specified or incorrectly supplied, then human error. Human malfeasance might be the latter case, where someone intently delivered substandard material or intentionally failed to build per design.

We see in the case of Kansas City that someone essentially altered the design during construction and completely changed the way certain components were loaded, resulting in an overload failure. No malfeasance, per se, but certainly some amount of duplicity, where the changed construction was not re-analyzed to determine its impact on the structural integrity of the final product.

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RE: Hard Rock Hotel under construction in New Orleans collapses...

Not sure if this video has been posted or not. Some good shots of the framing. No comment on the commentary.

https://youtu.be/7muzuf9Fmdo?t=1

RE: Hard Rock Hotel under construction in New Orleans collapses...

5
I feel a tad dumber listening to that commentary.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Another article that’s mostly speculation but some more quotes from workers speaking out about the design: Link

RE: Hard Rock Hotel under construction in New Orleans collapses...

2

Quote (Kreemerz )

But seeing these 'seemingly' random collapses like the pedestrian bridge at the Florida university is quite disturbing.

For me, what’s more disturbing than design errors in all these catastrophes we are seeing is that there were clear warning signs; there was still time to make the right decisions that could have spared lives. The cracks in the FIU bridge should have been enough warning to have stopped erection of that bridge. The early pilot complaints regarding the 747 Max8 controls should have been heeded and the planes grounded. The worker complaints about structural distress in the Hard Rock building (if the allegations are true) should have been deemed serious enough to stop work. We should scrutinize those decisions to push forward despite the warning signs as much as we scrutinize the design issues. That part of it really is a human nature issue.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (bones206)

We should scrutinize those decisions to push forward despite of the warning signs as much as we scrutinize the design issues. That part of it really is a human nature issue.

But money

RE: Hard Rock Hotel under construction in New Orleans collapses...

Cranes to be brought down by controlled explosion demolition within 24 hours. I'm betting sooner rather than later. Officials are trying to point to Friday, but I think it will happen today. They don't want too many hard-to-control people in the area, even outside the expanded exclusion zone.

According to expert spokespersons, it will look like the "cranes are melting".

https://twitter.com/nolaready/status/1184917477203...

RE: Hard Rock Hotel under construction in New Orleans collapses...

This was in the article, "Hard Rock Hotel collapse: Theories of fatal incident focus on weak shoring of concrete tiers", in today's New Orleans Advocate,

<<That corrugated metal decking was positioned differently along the edge of the building above Rampart Street than elsewhere on the building. That caused a “shearing point,” the worker said, that he suspects contributed to the collapse.

A former worker who requested anonymity on the advice of his attorney shared that theory and blamed midstream changes to the design of the building.

“It wasn’t the ironworkers. We did everything to engineered specs. I wondered if the engineers were really OK with it,” said the former worker. “The whole crew joked about how bad it was. We all joked we’d never stay in that hotel.” >>

RE: Hard Rock Hotel under construction in New Orleans collapses...

Blasting the cranes is likely to finish off the buildings from the falling debris and require taking them to the ground.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Thank you all for replying to me post. It explains a lot.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (NOLA)

Cranes to be brought down by controlled explosion demolition within 24 hours.

Holy crap. This is getting kinda crazy. I guess there's no hope of salvaging the concrete frame/PT levels? Certainly not after they drop two cranes on it. I will be very interested in how they rig these cranes. If it were me, I'd try to drop the tails (counterweights) off the towers - on to the street - before dropping the tower. Or maybe cut the tail and boom at the same time, then the tower later? They seem to be oriented such that the boom is over the structure, and tails over the street? At least they were when everything started happening.

And what's this about melting cranes? Clearly they're not supported by the upper slabs any more, but I don't see any melting...? But melting cranes would follow along with the current reporting/expert opinions...

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (dold)

Holy crap. This is getting kinda crazy. I guess there's no hope of salvaging the concrete frame/PT levels? Certainly not after they drop two cranes on it. I will be very interested in how they rig these cranes. If it were me, I'd try to drop the tails (counterweights) off the towers - on to the street - before dropping the tower. Or maybe cut the tail and boom at the same time, then the tower later? They seem to be oriented such that the boom is over the structure, and tails over the street? At least they were when everything started happening.

And what's this about melting cranes? Clearly they're not supported by the upper slabs any more, but I don't see any melting...? But melting cranes would follow along with the current reporting/expert opinions...

The statement was that when the cranes are brought down tomorrow (Friday), they will LOOK like they are melting. Just dropping straight down.

They are going to send up workers using a mobile crane that was brought in. They will use a blowtorch to cut some members, and place explosives in key places. Both the counterweight and the boom must be dropped at the same time. If the counterweight is dropped before the boom, the crane would be guaranteed to fall towards Burgundy St, destroying several neighboring buildings. I imagine the arms will fall first, then the tower will come down.

The city said that the demolition team will try to avoid disturbing where the bodies of the missing workers are thought to be and they would do everything possible to avoid damage to nearby historic buildings. If the podium levels of the Hard Rock have to be sacrificed, that is simply the way it will be. Plus, the neighboring buildings didn't cause this situation.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (3DDave)

Blasting the cranes is likely to finish off the buildings from the falling debris and require taking them to the ground.

I am not so sure.

The Level 8 three foot thick post-tensioned transfer slab will have a bunch of capacity - spans of only 25' feet etc. Even catastrophically, if there was to be punching shear failure through the RC columns - with hopefully a minimum of 2 code-mandated tendons running orthogonally over the supporting column 'cores' - the tendons will go into catenary action and avoid further progressive collapse.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Agree with Ingenuity. The photos early in this thread of the transfer slab would indicate that it is very robust. Maybe a few divots, that’s about all.

RE: Hard Rock Hotel under construction in New Orleans collapses...

This was on the news this morning. It is grainy cell phone video from (apparently) a few days before the collapse, showing various internal posts buckling.

Video shows workers were concerned days before Hard Rock Hotel collapse
https://www.youtube.com/watch?v=_p_3tiOesYY

RE: Hard Rock Hotel under construction in New Orleans collapses...

The steel floor deck was called out in the general notes to be continuous over three spans. I wonder if they were really counting on this as I can't imagine that this was possible with the spans shown on the drawings. Most deck manufacturers I have seen make deck sheets no longer than 40 to 45 feet which means most everything would have been single span. Since the deck was shored, I'm really not sure if it would matter, but it seems like it would affect at least deflections.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (StrucDesignEIT (Structural))

The steel floor deck was called out in the general notes to be continuous over three spans. I wonder if they were really counting on this as I can't imagine that this was possible with the spans shown on the drawings. Most deck manufacturers I have seen make deck sheets no longer than 40 to 45 feet which means most everything would have been single span. Since the deck was shored, I'm really not sure if it would matter, but it seems like it would affect at least deflections.

A co-worker and I were just talking about this when I came in this morning.

1) 3 span condition absolutely increases the capacity of the deck system - max negative moment of 0.1*wl^2 and max positive moment of .08wl^2.
2) Unless there was some special lapping called out, I don't know how you 3-span 25' bays with 45' maximum length sheets.
3) It's highly likely that the general notes were just a boiler plate.


Of note, Vulcraft's 3" composite tables only go up to 15' span length.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (winelandv)

It's highly likely that the general notes were just a boiler plate.

I know when I specify a 3-span condition, even just "boiler plate" notes, I check for it in the deck shop drawings. If there is a condition that is not 3-span, then I make sure it still works. I've seen the same 15 foot max span in the CMC tables.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I have stopped using the permit drawings as anything more than a way to get spans and general layout. I don't think we can really gain much by using the notes and sizes in the drawings at this point. We will have to wait to see if there is a revision set or see if there were extensive mark-ups in the shop fabrication drawings or the steel decking submittal.

RE: Hard Rock Hotel under construction in New Orleans collapses...

From the photos, this appears to be something like versa dek long span dovetail composite deck. With negative moment steel, which was visible in the photos, it can span 25’+ (If shored during construction)

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (IceNine)

From the photos, this appears to be something like versa dek long span dovetail composite deck. With negative moment steel, which was visible in the photos, it can span 25’+ (If shored during construction)

The permit set only called for 3" 16ga VLI decking with a 5.5" total thickness slab. The versa-dek I believe only comes in 2" or 3.5" depths. Must have revised something.

RE: Hard Rock Hotel under construction in New Orleans collapses...

If you look at Tomfh’s post from 14 oct 19 23:04, you can see the dovetail deck and rebar. Looking at the length of the headed studs, the slab appears thicker than 5.5”
It’s definitely not a VLI composite deck

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Sandman21)

They may have to wait longer still...

I seriously doubt that motion will affect the crane implosion. It appears to be focused on documentation and evidence. And even if it did cover the wreckage as it stands, authorities have a duty towards public safety that overrides such legalistic concerns.

RE: Hard Rock Hotel under construction in New Orleans collapses...

They already have evacuation zone which would include the crane fall zones. Legal concerns have a way of popping up and delaying things.

RE: Hard Rock Hotel under construction in New Orleans collapses...

if someone can get me the plans I'll try and figure out if it should be stable

RE: Hard Rock Hotel under construction in New Orleans collapses...

what was the wind like that day? Is it possible the crane sent vibrations in mode?

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (IceNine)

From the photos, this appears to be something like versa dek long span dovetail composite deck. With negative moment steel, which was visible in the photos, it can span 25’+ (If shored during construction)

Yes but should you?

With a 5 1/2" total slab thickness, even if it was pure concrete (no deck flutes) and reinforced to the maximum I'm not sure I'd do that.
The long term creep deflections would be significant I think.

ACI, for "recommended" thicknesses of continuous slabs for 25'-9" suggests 11" thick slabs.
Running some quick numbers for a 25'-9" span, I'm getting pretty large D and L deflections...not to mention long term conditions.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Robert Soley)

what was the wind like that day? Is it possible the crane sent vibrations in mode?

I've been pointing towards the wind since Monday, as I was nearby on Saturday morning, and the wind was VERY strong. We had to hold down our tent at the Farmer's Market, even with stakes. One of the umbrellas went airborne and almost hit someone. Wind was the main thing that was different as compared to the days before the collapse. Also, the building below the 15th floor (approx. 150 ft) or so was nearly fully clad. Wind coming down Canal St would roll over the Saenger Theater (about 45 ft tall) and hit the cladding. Then, all of that air would have to go over the highest clad floor to the first open floor or go left or right around the building. I think it would take wind tunnel analysis to figure out the wind speed over that first open floor. The highest sustained wind was 16 mph at the MSY airport. Maybe Lakefront Airport (closer) has some more applicable data for that morning. Also, gust are typically 30% higher than sustained winds.

I think the cranes may have initiated the collapse, regardless of where it appeared to fall. Where is the crane operator? How was he or she able to climb down to the roof and escape the collapse? Maybe he/she felt something or heard something that said, "Get out" a minute before collapse.

Please elaborate on "crane sent vibrations in mode".

RE: Hard Rock Hotel under construction in New Orleans collapses...

Vibrations, usually in seismic zones but to a lesser extent impacts and wind to a lesser extent are controlled for. If these were amateur contractors who have never practiced out of state they may never have even heard of vibrations in buildings. Vibrations are like shock waves through the buildings--where if, like a pendulum, the vibration strikes while moving in one direction, it moves further. You can calculate the stress backwards from the deformation. I would guess if they went off of the original plans and instead built slimmer these vibrations would have a greater effect. The vibrations coming from the crane.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Wind,vibrations, cranes...sorry, but these sound like excuses, not reasons for a construction failure like this one. Look elsewhere for your speculations.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Gravity is the typical culprit.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (hokie66)

Wind,vibrations, cranes...sorry, but these sound like excuses, not reasons for a construction failure like this one. Look elsewhere for your speculations.

I agree with hokie66.

All things considered, like post-shores buckling, large L/D ratio for beams and metal deck slabs, cantilevers with no backspans etc - and the fact that the 2 tower cranes are still standing (just?) - leads to framing issues.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Our point is that "Wind,vibrations, cranes", in COMBINATION WITH large L/D ratio of beams and deck span, might be the culprit. Sure, winds have affected cranes since the first one was ever used on a construction site, but the designs of a decade or more ago were more robust to these forces. It seems that every member on this building design had a FS of about 1.00001 for the design loads. Not a good practice, especially with little to no redundancy.

"2 tower cranes standing" -- An element can cause failure without failing itself. I can break a branch with my arms and leg, but neither of those is broken in the process. These cranes are anchored to pile caps and at least wedged into the PT garage decks and framing.

I just don't get the use of "cantilevers with no backspan", but I doubt that the failure started with those, unless we see some other evidence about what happened first in the failure. We'll say the jury is out on that one for now.

RE: Hard Rock Hotel under construction in New Orleans collapses...

It was built as a house of cards and wasn't getting stronger; it seems inevitable that it would collapse and wind, vibration, or a dropped nail could all have been the trigger - but they don't matter if the structure was fundamentally flawed in design or execution. Something would eventually be the triggering event. It's tin-foil conspiracy level logic to care what triggered this.

RE: Hard Rock Hotel under construction in New Orleans collapses...

true that it is useless to speculate--if they're taking it down. But I had an idea about a steel cable mesh held by trunnions held in some manner; which could vary; which would dictate the final result of the structure.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

It's tin-foil conspiracy level logic to care what triggered this.

It is NOT tin-foil conspiracy level logic to care what triggered this. Even if the design was flawed (and we only have access to PERMIT drawings at this point, not the final drawings they were using over the past few months), it is still important to know where and why it started. Something new might be learned. It's not a certainty, but it is worth the effort to try.

And Robert S, where was this: "a steel cable mesh held by trunnions held in some manner".

RE: Hard Rock Hotel under construction in New Orleans collapses...

I didn't mean a steel cable mesh held by trunnions was IN the building, but should be the course of action that proceeds

RE: Hard Rock Hotel under construction in New Orleans collapses...

Well the crane implosion did not seem to go exactly as planned:



RE: Hard Rock Hotel under construction in New Orleans collapses...

It would seem that the situation is now more precarious than it was before the charges went off.

I am no expert on demolition like this, so I will leave my comments to the experts, but the cranes did not appear to melt away, as we described prior to the blast.

Typically this work takes months of planning. Maybe trying to do this in a few days was asking too much.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The way that one crane impacted the roof framing, they are lucky they didn’t trigger another collapse.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Video of the crane demolition:
https://www.youtube.com/watch?v=yjclkwiGUkI
At this point, I would be inclined to request the army to send a tank over and see if a few strategic shots couldn't improve the situation.

Reminds of a quote from long ago, recited as best I remember it:
"There was a fire in the hotel. It was a 3-story building, and old man Hawkins was trapped on the 3rd floor. None of the ladders in town were long enough to reach him. With great presence of mind, I shouted "Fetch me a rope!" and presently, somebody brought me a rope. I threw one end up to old man Hawkins and said "Tie it around your waist!" He did so, and I pulled him down." (Attributed to Mark Twain)

RE: Hard Rock Hotel under construction in New Orleans collapses...

(OP)
One out of two ain't bad winky smile

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RE: Hard Rock Hotel under construction in New Orleans collapses...

The one on the left ended up on its "head" but still vertical - apparently on the street below.
Now they just need to saw the bottom off at an angle so it properly falls in line with the street and not diagonal into adjacent buildings!

RE: Hard Rock Hotel under construction in New Orleans collapses...

What made traditional crane disassembly methods more dangerous than the controlled explosion route? General instability of the structure?

It would seem a lot would have to go right for the implosion route to go off without a hitch. Can anyone speak to normal success rates?

RE: Hard Rock Hotel under construction in New Orleans collapses...

In the post-implosion press conference this afternoon Mayor LaToya Cantrell stated:

Quote (Mayor Cantrell)

"We want a complete demolition," Cantrell said. "That’s our focus, and that will be our mission."

I thought they may have preserved the first 8 levels of PT concrete construction (assuming adequate structural assessment etc), but I guess such preservation may come with 'bad vibes' for what holds of future use.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I dont understand why they didn't take off the crane booms the 'normal' way, with another mobile crane. Too risky? Riskier than an explosive demolition?

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (OHIOMatt)

It would seem that the situation is now more precarious than it was before the charges went off.

I am no expert on demolition like this, so I will leave my comments to the experts, but the cranes did not appear to melt away, as we described prior to the blast.

Big improvements:
(1) The Iberville St crane is essentially down, as planned
(2) BOTH counterweights are down; the booms are no longer turning in the wind;
(3) The Canal St crane is now just a tower and a bent boom, which can probably both be removed piece by piece, and they are probably in a fairly stable configuration, especially with a little help from temporary supports

Quote (OHIOMatt)

I dont understand why they didn't take off the crane booms the 'normal' way, with another mobile crane. Too risky? Riskier than an explosive demolition?
There was no longer reliable support for the towers, especially for the Iberville St crane. Remove the counterweight and what will happen? Remove the boom and what will happen? Way too risky and would take weeks. Nearby businesses, including the Saenger Theater, have been closed for a week. People were unable to live in their homes (maybe still displaced??).

I think the mayor is wrong to want complete demolition. Why throw away 8 floors of post-tensioned concrete? Build a better building on top of that, but NOT another hotel!

RE: Hard Rock Hotel under construction in New Orleans collapses...

Something else to note per S1.0A "FLOOR DECK SHALL BE SUPPORTED AROUND ALL FLOOR OPENINGS AND COLUMNS." I'm sure this is standard boiler plate but when it come to litigation and placing blame the attorneys will argue the SHALL was not done.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Wow. That’s one way to get rid of some cranes.

RE: Hard Rock Hotel under construction in New Orleans collapses...


The demo guys had one chance to get it right the first time...and they blew it.

I'd like to know how far the top section of the tower on the left is buried in whatever it landed on. Talk about sticking the landing.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Well, the chief of the NOFD says it went pretty much as expected. It did damage a sewer line, but that was planned for. The news video shows that most of the tapered section of the tower above the boom is buried in the street, and the now-inverted upper part of the tower appears to be stable.

https://www.youtube.com/watch?v=kyoSdfUkASo It's a looong video. The good part starts around the five hour mark.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Impressive considering they avoided the catenaries for the street cars.

RE: Hard Rock Hotel under construction in New Orleans collapses...

It's tragic that lives were lost in this collapse. So many aspects of the structural design are extremely questionable. However, I imagine if this structure did not collapse now, it would have later when potentially filled with thousands of patrons. So maybe a bullet was dodged.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Or, rather a bullet wasn't dodged but the artillery shell was.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Hard Rock Hotel under construction in New Orleans collapses...

They speared the crane tower into the street. Like a giant lawn dart. Pretty sure that was not planned for. Also it seems like no one did a dynamics simulation for blasting or they would have not have blasted the towers until the initial motions had completely stopped. Instead they flipped a big part of the crane off the property, thankfully missing hitting anything else.

Still, as mis-planned events go, it could have been worse.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Retiredat46)

The demo guys had one chance to get it right the first time...and they blew it.

There were a lot of random factors to the way the towers were damaged in the initial collapse, the situation was steadily deteriorating, weather was coming in, and there wasn't time to do exhaustive analysis they way you'd do with years or months to spare. Personally, I think they played the hand they were dealt about as well as might be expected, and it turned out way better than it could have. Nobody else was hurt, property damage was held to a dull roar, and the situation was made a lot more stable.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I cant help but wonder how many of these monday morning quarter back players, have ANY blasting experience whatsoever.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (miningman)

I cant help but wonder how many of these monday morning quarter back players, have ANY blasting experience whatsoever.

I have zero blasting experience.

Why would they only sever the support cables at the top of the crane and not the connections where the tower meets the boom and the tail?

RE: Hard Rock Hotel under construction in New Orleans collapses...

2
(OP)
My 'blasting' experience goes back to a very short time in the ARMY Corp of Engineers (Reserves). Never actually got to blow anything up, just some classroom work learning about stuff like C4 and other military-grade explosives.

Note that this was during the Vietnam era, and one of our instructors explained the two best reasons for being in the Corp of Engineers. First was that since we traveled with our own power generators, we always had cold beer. And second, we had C4, so we could 'dig' a foxhole in a minute or less, without working-up a sweat.

John R. Baker, P.E. (ret)
EX-Product 'Evangelist'
Irvine, CA
Siemens PLM:
UG/NX Museum:

The secret of life is not finding someone to live with
It's finding someone you can't live without

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (HorsieJuice)

I have zero blasting experience.

Why would they only sever the support cables at the top of the crane and not the connections where the tower meets the boom and the tail?

Those are probably the most robust pieces of the crane? I'm guessing they would use some sort of shaped charge to do that. Between getting all of that placed on a tight time schedule and maybe some concerns about containing it all (i.e. not sending high velocity shrapnel a mile away), the cables were just easier.

RE: Hard Rock Hotel under construction in New Orleans collapses...

They severed the cables at the top because they carried the weight to balance from one side to the other. By severing those cables the loads on both sides were simultaneously released. What they didn't seem to appreciate is that leverage brought the two significantly different weights into balance and without that cable the leverage was removed, leaving the unbalanced weights to act independently.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Spartan5)

Those are probably the most robust pieces of the crane? I'm guessing they would use some sort of shaped charge to do that. Between getting all of that placed on a tight time schedule and maybe some concerns about containing it all (i.e. not sending high velocity shrapnel a mile away), the cables were just easier.

If you're trying to drop the tower in a specific spot, I'd think the forces applied by the falling boom & tail would prove to be significant factors that you'd want to control. The attachment to the boom is what kept the one tower upright and the attachment to the tail is what appears to have started the other tower tumbling end over end as it fell.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (XR250 (Structural)21 Oct 19 13:42 It's tragic that lives were lost in this collapse. So many aspects of the structural design are extremely questionable. However, I imagine if this structure did not collapse now, it would have later when potentially filled with thousands of patrons. So maybe a bullet was dodged.)


I have said this exact thing to my colleagues. Couldn't imaging something like this happening with full occupancy - like Mardi Gras or the 2024 (?) Super Bowl.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Note 18 under Steel Notes on the permit drawings: "THE STEEL FRAME IS "NON-SELF SUPPORTING". ADEQUATE TEMPORARY SUPPORT MUST BE PROVIDED BY THE CONTRACTOR UNTIL REQUIRED CONNECTIONS OR ELEMENTS ARE IN PLACE."

That note is vague enough to cover a multitude of sins, but it is telling that some on the jobsite and photographic evidence, post-collapse, have indicated that in many cases only two bolts had been installed, even on floors that otherwise seem to have complete framing. Someone will have to look at photos and the building in its current shape to determine if the "connections or elements" were in place.

RE: Hard Rock Hotel under construction in New Orleans collapses...

After looking over the plans (which I lost and can’t find now) if I may offer a few observations:

1. The tubes attached to the spandrel beams are structural as demonstrated by the orthogonal deck span that changed directions in the cantilever.

2. The beam supporting the cantilever would be in torsion unless it is tied back by the back span reinforcing.

3. I see no serious back span top steel steel the back span in close ups posted at the failure (such as with the man in the yellow suit)

4. I see that the cantilever steel is in the second layer of steel in the failure area if the steel exists.

5. The effective depth of the cantilever steel, if existent, is about only an inch or so in the failure area which further illustrates the structural nature of the HSS sections.

6. Since the outer slab cannot function as a cantilever, its load would be taken to the cantilever beams, then to the shores.

7. I propose that the shores may not have been removed after pouring each slab, therefore leaving the load in the shore rather than transferring it to HSS sections.

8. The shores finally buckled due to over-load of carrying multiple floors and the collapse proceeded.

9. Could it be that the HSS tubes were to connect to something else at their cantilever end to support them and "make it good" and were to be shored until that time?

Regards to all.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I was wondering the same thing and had looked for answers in the later (5-1-19) architectural drawing set. Some sections show a curtain wall below the cantilevered tubes, but I do not believe they would be designed as load bearing elements. There is a gap with backer rod and caulking shown between the top of the curtain walls and the structural framing above.

But who knows? Maybe the curtain walls were meant to be load bearing and that’s what the note about “non-self-supporting framing” and “required elements” was referring to.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The non self supporting frame note is common for steel frames. When we use a similar note, it refers generally to lateral stability. Erectors typically use temporary cables to brace the steel frame until lateral braces are installed, moment frame connections are complete, metal decks/concrete slabs are installed.

RE: Hard Rock Hotel under construction in New Orleans collapses...



View of the underside of the (load transfer) 16th floor showing framing different than plans submitted with the permit, obviously they had been revised. It would be nice to get a copy of the latest revisions.

RE: Hard Rock Hotel under construction in New Orleans collapses...



Double cantilever in the photo above is interesting. I don't see how it could possibly work at the slab and metal depths assumed. No beam to take the load. Was the bottom steel deck split at a 45 degree angle?

I could find no plans for reinforcing the metal deck with top and/or bottom steel.

I have the printed permit set now. It is obvious much is missing from them and many changes were made as discussed in this forum.

Regards,



RE: Hard Rock Hotel under construction in New Orleans collapses...

Wow. This can't be real life. If they removed those two shores....

RE: Hard Rock Hotel under construction in New Orleans collapses...

It's hard to tell with the quality of the photo (at least, the quality as it shows up on the webpage, maybe the original is better), but it almost looks like the decking is at a 45 degree angle to the supports in that corner..? It may just be weird shadows.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Can you apply for a code exemption to the effects of torsion in North America?

That double cantilever looks mighty suspicious to me given the beams/girders appear to be I sections. I cannot comprehend how that even works unless the beams were simply there as permanent formwork to support the metal decking and the slab topping thickness did all the business cantilevering over the main beams. Either way it seems like the designer missed something fundamental if the framing that's visible was intended to be the final structure.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I think the designer missed a lot of fundamentals.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I think we’re largely guessing as to what’s going on with the apparantly unsupported cantilevers.

There are a lot of questions about this structure, as there are when any structure falls down. But we should probably stick to what we know for sure.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Another view of the underside of the (load transfer) 16th floor showing framing

RE: Hard Rock Hotel under construction in New Orleans collapses...

Interesting, GPR Tech's picture shows the cantilever holding up without shoring. I saw in some earlier pictures what appeared to be rebar in the slab. I wonder if the intention was for the concrete to act as a cantilever? I suppose if we ever get to see the final drawings we will know.

One thing I can't quite get my head around is even with the weak overhang and long span on interior decking is why there was so much of the building that collapsed? I can understand localized collapse but why the whole front part of the building? It seems like the steel frame would have the ductility and strength to have stopped a local collapse of the deck.

I personally find this one more interesting than the FIU bridge collapse. The design seemed to have some very obvious deficiencies in the plan set (long span's, questionable cantilevers) that many people experienced with construction would have noticed. It is also a fairly typical project without many (any?) technically challenging elements like the FIU bridge.

I wonder if this will get the same level of investigation and data disclosure that the FIU bridge has. The cause of this collapse is probably more relevant to many structural engineers daily practice than the FIU bridge.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Elevator Towers without diagonal bracing installed.
Has anyone seen any photos showing Elevator Tower's diagonal bracing installed on any other elevation?

RE: Hard Rock Hotel under construction in New Orleans collapses...

GPR tech,
In looking at the photos, it appears they switched to moment frames at the cores.

RE: Hard Rock Hotel under construction in New Orleans collapses...



First, I would like to thank all the people who are contributing to this
Forum. Your observations are valuable to all of us who are trying to
understand this failure.

In reply to Ideem, I agree. The problem is clearly more than a bad cantilever
detail. The steel frame would should have absorbed a couple of cantilevers collapsing
without the building coming down like it did.

As to some reasons why, all of which have been quoted by others previously:

1. Bolts were shown missing in one post.
2. A weakness was identified where hardly any steel beams cross the building
longitudinally just below line 10.
3. The failure photo below show a large section of the building falling virtually intact.
4. Steel was seen in previous post not crossing steel beams at the studs, but stopping at them.

Were many bolts missing in addition to the clear design errors on the permit plans? The practice is
normally to place a couple of bolts in the beam as it is set, and before the floors are added, to place the rest.

Though the failure may or may not be related to the cantilevers, it is clear that many much more serious problems
existed at lower levels as illustrated by the photo below.

By the way, these beams are not composite steel beams. I checked a few and found that the studs were not
sufficient for composite action. They merely attach the slabs through the deck to the beams.

Regards,

Sorry. I do not know how to upload my image. Look at the failure video for part of the building falling virtually undamaged.





RE: Hard Rock Hotel under construction in New Orleans collapses...


The building failed longitudinally along line 11 next to the elevator and stair towers. There are hardly any steel beams crossing the line from line 10 to line 11 as noted above.

The failure at line 11 separated the building into two parts, that which stood up and that which failed. This mass of falling concrete would be more than enough to cause the failure of the steel structure below considering the weakness of the lightly connected sections of building.

Note that the portion that fell was no longer connected to the cores for lateral stability. Connections of the beams to columns were likely shear only with little moment resistance. Nothing was holding it back but metal deck and steel reinforcing. Once it started to lean, failure was assured.

Failure below is still a possibility but a frame by frame look at the failure video leads me to suspect it occurred from the area of the top down.

RE: Hard Rock Hotel under construction in New Orleans collapses...

One last comment before bed:

A post by Tomfh on 14Oct19 at 23:04 clearly shows that there is no top reinforcing bars crossing line 11 beam which is seen in front of the workman by himself in the green shirt. You can see the line of Nelson studs on top of the beam where the reinforcing steel stops.

The reinforcing steel should have extended over the beam on both sides for negative moment and may have helped stop the progressive collapse but for some reason it was misplaced.

"Plagiarism is stealing from one, research is stealing from many."

Regards,

RE: Hard Rock Hotel under construction in New Orleans collapses...

MOJOJOHN,
Take a closer look, it appears the bars do extend beyond line 11.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I understand the intent of this thread is to discuss and dissect the true, physical nature of the collapse. But I hope we can all agree that there was no single deficiency that this collapse can be attributed to: not the missing bolts, not the lack of beams crossing the corridor, not the cantilevers, etc.

This was entirely preventable. This particular collapse is absolutely due to a failure in the HUMAN element of our system of design and construction. Collapse was inevitable. If it wasn't going to be the cantilevers, it was going to be the deck. If it wasn't the deck, it was going to be the load path. On and on... We can all sit around and agree that there were countless design flaws in this structure, at least based on what we have seen so far.

In my opinion this collapse is unprecedented in terms of the human/ethical factor of engineering. Look at the Hyatt bridge collapse. We know what caused that: the failure of a single component due to a (hastily) approved substitution that did not recieve proper attention. Not due to extreme incompetence. FIU bridge: due to (perhaps) a true misunderstanding of the nature of materials and forces and their interactions, and a lack of what amounts to backbone on the part of review, and almost certainly a degree of pride in most parties. The Hard Rock collapse seems to be the result of true, unfettered incompetence. There are so many checks along the pipeline that could have prevented this, starting at the EOR, and ending at the AHJ. I can't go beyond that and fault the GC or subcontractors for refusing to build an obviously deficient structure, as that is decidedly not their job (or is it?). The real question here is where that breakdown occurred, and why.

This has seriously dismayed some of the professionals in my office. Truly shocking how something like this could happen. I'm curious to hear what some of the other - professional - reactions to this have been? Thoughts?

RE: Hard Rock Hotel under construction in New Orleans collapses...

IceNine,

Thank you.

Please show me where the steel going between 10 and 11 is. I have looked at the plans, a good mark up in green forum member and photos and cant seem to find it.

I am getting older, maybe I need stronger glasses!

Regards,

RE: Hard Rock Hotel under construction in New Orleans collapses...



I assume this is the post you are looking for? It is from JAE on 10/15/19 @ 17:06 (not sure if this time is location specific in the world or if it is GMT).

RE: Hard Rock Hotel under construction in New Orleans collapses...

dold, you asked for reactions.

Regardless of what is determined to be the ultimate cause of the collapse, this tragedy was completely avoidable. The video of thee buckled shore posts taken on Thursday before the Saturday collapse should have been enough evidence to evacuate the building and determine what is going on.

This thing passed through numerous hands before it got to the erection phase. I believe that design changes occurred after the permit set was issued, but the following groups had access to the design drawings. The design still has some very questionable issues based upon photos of the actual construction.

1. The EOR and team should have internal checks and back checks associated with the design process.
2. The architect should have been able to look at the permit drawings and question them. Looking at member sizes and spacings and comparing it to other projects, should have at least aroused suspicion of a problem.
3. The building department. While they are not structural engineers, they should have enough knowledge to see obvious design deficiencies, at least to the point of asking questions, requesting calculations for validation, ect.
4. The Structural Steel Fabricator should have recognized that sizes and total tonnage of steel did not correlate to a building of this size.
5. The structural Steel Detailer should have flagged some of the obvious issues in the permit drawings.
6. I assume that this project used delegated design for connections, the engineer designing connections should have recognized some of the obvious design issues.
7. The deck supplier should have noticed the span issues with the deck specified.
8. The shoring designer could have questioned noticed some of the design issues.
9. The EOR should have seen the fabrication drawings and noticed problems before this went to the shop.

Once we get to the erection phase
10. The erector should have questioned the design (seems like this did happen to some extent)
11. The shoring contractor (this did happen as noted in the video by the guy removing the shoring posts)

Maybe, red flags were raised throughout the process and the public has not been made aware them. My point is, that so many people saw the design and could have flagged it. I have to believe (maybe I just really want to believe) that questions were asked along the way. I think that the telling part of this story will be in the communications related to the project. I would expect there to be an extensive RFI log and e-mail chain on this project. Hopefully this will provide some insight on how this could have gotten to this point.

I have read the report for the FIU bridge collapse. I believe that the final report will raise similar issues in regards to who can shut work down and evacuate strutcures.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I'd love to know more about the interaction(s) between the EOR and the architect, Harry Baker Smith. The architect has a professional responsibility to propose a design that can be supported by the structural engineer (and provide for other services, such as electrical, mechanical, HVAC, etc.) without the need for 'skyhooks'. When the column layout from the architect is not aligned from floor-to-floor, the design becomes needlessly complicated and expensive. I know it's up to the structural to do whatever the architect calls for as far as column placement and beam spans, etc., but the architect's proposal has to be reasonable, too.

If you look at the plans for the upper floors, there are a ridiculous number of column lines.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (OHIOMatt)

3. The building department. While they are not structural engineers, they should have enough knowledge to see obvious design deficiencies, at least to the point of asking questions, requesting calculations for validation, ect.
Isn't that why they issue (or deny) building permits in the first place?

Brad Waybright

It's all okay as long as it's okay.

RE: Hard Rock Hotel under construction in New Orleans collapses...

thebard3

One would think so, but in my experience, it is extremely uncommon for the building department to make any substantive comments on a buildings structural design. The one exception to this is the west coast, they either have reviewers that are well versed in building structures or they outsource the structural review.

In my home jurisdiction, they add a stamp to the plan set that reads something like "The design of the building structure has not been reviewed, it is up to the professional of record to ensure the safety and stability of the structure".

Most of the time, when I do get comments, they are of little to no value. Things like "Provide H-clips at roof sheathing boundaries".

I have seen obvious errors overlooked more times than I can count. There is a misconception in the public that by the building department issuing a permit, that the building meets the requirements of the code. It all comes down to the engineer of record. I guess that is why, in our state, that building officials are immune from civil liability.

RE: Hard Rock Hotel under construction in New Orleans collapses...

OHIOMatt, your experience is similar to mine. Really the only comments I get from a building official are almost always specific to code language. There is no code language against bad details or long deck spans.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Yup. Unless there is some factor the building permit people know about in particular (residential fence height; set back limits), I would not expect any deeper review than checking the plans are stamped by a current licensed engineer. If that were not the case, then there would be no point to having licensing in the first place.

RE: Hard Rock Hotel under construction in New Orleans collapses...

The converse of that is that if the jurisdiction's reviewing could make substantive changes to the design, then they would be liable, and having deeper pockets than the engineer, they would never entertain taking on that kind of risk.

TTFN (ta ta for now)
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RE: Hard Rock Hotel under construction in New Orleans collapses...

Permit comments pertaining to Structural engineering appear to vary depending upon municipality. Building Department's regularly make comments regarding to Zoning, health safety and architectural elements - among many others. A review by the building department on the Structural framing elements should be considered to be as important as the review of these other elements. There is not enough incentive, however, as it compares to the money in zoning issues, the fire departments involvement in health safety and the public's perception of architectural elements. Structural engineering is sadly viewed as a "check-box" to many players in the construction/development industry. In combination with shrinking fees, increased complexity in project delivery and increased expectations from owners this has structural engineering squeezed from all sides. This is not to preclude the responsibility of the engineer of record, or any other party, on this topic. Once the dust settles and if the collapse can be attributed to some of the design faults described on this thread I hope that one of lessons learned is that building departments should provide a service to the public beyond just a rubber stamp when it comes to a review of the Structural Engineering a building.


RE: Hard Rock Hotel under construction in New Orleans collapses...

BadgerPE,

Thank you, that was the post I was looking at.

IceNine, I see no reinforcing steel across the 10 line down to the 11 line in the above repost by BadgerPE. Am I missing something?

Also I was discussing this area with a very large building contractor today and it was his feeling that
the crane attachments would likely damage the otherwise un-reinforced strip as the crane moved under load, possibly breaking spot welds.

Regards,

RE: Hard Rock Hotel under construction in New Orleans collapses...

Looking at link of video, thanks JohnRBaker and dold, at start of thread

https://www.youtube.com/watch?v=D_LxF8IjH3s

Unfortunately the video starts a little late to capture start of collapse, rewind and pause at 0 seconds. If video was shot from North, take a look at the North Elevation, there appears to be a sliding cantilever deck usually used during construction (not permanent structure) , yellow in color, that was originally supported by the third level from the top that has already displaced to nearly the level below, less than a second into the video the deck has already reached the level below. The sliding deck appears to be supported on the edge by a thin cantilever concrete metal deck slab. There does not appear to be any reshores below the sliding deck at the concrete slab edge.

Photo posted by GPR Tech on 24 Oct. 2019 shows similar deck, does not appear to be reshores under this one either.

No reshores under a thin cantilever deck seems highly unusual to me, and I have designed supports for several of these types of decks.

Can't tell from the video if collapse is just now reaching the cantilever deck or the cloud of dust beyond is just now reaching from the collapse of the deck.

RE: Hard Rock Hotel under construction in New Orleans collapses...

MOJOJOHN,
If you look at the second photo in Tomfh's post, 14 Oct 19 23:04, you can see rebar crossing the 10 and 11 lines.
It is hard to see because the rebar is parallel to the deck flutes, but if you look closely, it's there. There are two rows of bolsters on the deck and you can see the rebar extend past the beam with headed studs closest to the man in the green shirt.
None of this rebar is shown in the permit drawings.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (MOJOJOHN)

Also I was discussing this area with a very large building contractor today and it was his feeling that the crane attachments would likely damage the otherwise un-reinforced strip as the crane moved under load, possibly breaking spot welds.

Ah, so we are back to the thing that was different about the morning of October 12th as compared to previous days: WIND pushing on the cranes.

New information has come out today. One of the bodies was recovered and identified by the man's widow at the Orleans Parish Coroner's Office. She reported that he was a plasterer and she was told that his body was found on the 7th floor. The 7th floor is part of the parking garage structure, right below the 8th floor transfer slab (podium slab). Just food for thought.


RE: Hard Rock Hotel under construction in New Orleans collapses...

I'm new to this forum and learning a great deal from the structural discussions. It is my experience that collapses like these are usually construction accidents caused by a sequence of events. Hard to analyze because the load or stress is no longer present. Does anyone know if there were operators in the cranes at the time of the collapse?

RE: Hard Rock Hotel under construction in New Orleans collapses...

IceNine,

I stand corrected. I see the steel crossing between 10 and 11 and I do need new glasses which I will get this week.

With regards to the crane coming up again, just because an idea is old does not mean it is bad. The constant pounding of steel deck
with or without wind is a factor that should be considered.

Regards,

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (TGHAN)

Does anyone know if there were operators in the cranes at the time of the collapse?

Someone -- either on this forum or on a YouTube channel that has been discussing this collapse in detail (I won't say 'analyzing' because the guy knows nothing about structural engineering, steel design, or concrete design) -- said that they saw the crane operator scrambling down the ladder to the roof level. I haven't been able to see this on numerous viewings of the collapse video. The Iberville St crane was holding a rather small steel beam that was being attached to a mechanical room on the roof level at the time of the collapse. The other crane did not seem to be in operation at the time of the collapse -- at least it wasn't connected to a lift load in the videos after the collapse.

Best I can tell, the crane operators have not talked to the media. OSHA has certainly talked to them, so again, the OSHA report should be enlightening.

We found out last weekend from the wife of one of the deceased that he died on the 7th floor, which surprised me because all images seem to show that the parking garage up to the 8th floor podium slab seemed to fare well, even with the building above dropped on the 8th floor podium. Speculation is that he may have died when one of the post-tensioned cables failed. But perhaps he was on the 7th floor, near an outer wall (he was a plasterer) and was killed by tumbling debris and the post-tensioning is fine. I guess we will find out when OSHA makes its report in 6 months or so. EDIT: Part of the 7th floor extends beyond the extents of the 8th floor, so this area is where he might have been.

Referring to a second victim (from an article yesterday in The Advocate, NOLA.com), "Wimberly’s body is under rubble on a section of the 11th-floor near North Rampart Street, but crews have been unable to retrieve it."

I'm wondering if the concrete in the upper decks met the specs, especially with regards to maximum aggregate size. In some photos, you can see rocks the size of a quarter, probably, in a 5 1/2" thick deck (as most are in this building). This might affect bonds strength with the rebar crossing the center corridor of this building.

The change is direction of the decking may have also contributed to the collapse, both in the 'corridor' and the cantilvers. This EOR and contractor have built 2- and 3-story buildings with this sort of decking on the overhang, but maybe the effects of more floors, plus shoring and column offsets, combined to create the collapse.

So far, we have only seen the structural permit drawings, from more than a year before the collapse, but there were revised architectural drawings from just a few months prior. So, there may be a newer set of structural drawings. I think it is suspect that many engineers here, even those with experience in high rise design, have viewed the permit set, yet most here are still mostly confused by the design. A design should make sense to professionals, shouldn't it? Again, maybe a better set exists.

RE: Hard Rock Hotel under construction in New Orleans collapses...

New drone image of the building.

RE: Hard Rock Hotel under construction in New Orleans collapses...

We have found what may be the cause of the collapse!

I apologize in advance if this post seems disorganized, as it was cobbled together from a few different discussions.

Today I watched this video, https://www.youtube.com/watch?v=FnamR5GLnbg, "HARD ROCK COLLAPSE ULTIMATE LOAD PATH FAILURE 15TH..." Watch that video at about 30:40 to see the initiation of collapse in the area of the curved Rampart St side of the building. (I love this 'new' pool view of the start of failure that came out last week. I kept wondering when we would see security camera footage.) The rest of the video discusses the location of failure in non-technical language.

Someone shared this excellent analysis of the loading and framing at the 15th Floor privately with the person who produced that video: https://ibb.co/PtZcQR4

In commentary for that video, a user named Bobby posted this 3D view of the framing above the 13th Floor that is very helpful:
https://www.docdroid.net/Mqs38gZ/capture.pdf

I had tried to sort out this framing, but I just didn't have the patience for it. There are so many different column lines and rows. As on the first link above, it's obvious that on the Rampart St side, the columns at the 15th Floor do not line up to directly support the columns from the 16th floor. It's also pretty obvious that the beams at the 15th floor are not big enough to act effectively as girders to support the loads from the 16th Floor, 17th Floor, and the "Roof". (I couldn't easily find the dimension from Col Line HH to JJ on the 15th Framing Plan, so I gave up and made a reasonable assumption.) There is so much variation in the column lines and spans that it seems that each and every beam would have to be evaluated separately. (In the days of hand calculations, we would have made the spans and framing more uniform.)

As a start, I checked one beam on the 15th Floor, the beam between BB & JJ at Col Row 10.2. The following is what I found.
(Note that it's possible that the beams in Col Row BB and JJ are worse than the beam from BB-JJ, but I didn't have time to check that yet.)

My findings and assumptions are:
(1) Did NOT analyze as composite concrete and steel beams, as MOJOJOHN says the studs are inadequate for composite action.

Quote:

By the way, these beams are not composite steel beams. I checked a few and found that the studs were not
sufficient for composite action. They merely attach the slabs through the deck to the beams.

(2) I looked at the loading on the W16x26, loaded at approximately 10'-6" from Col Row JJ, with loads from Floors 16, 17, and Roof above via the column I will call "FF.1"
(3) At Floor 16 (and 17) in Col Row FF.1, the W10x19 carries the floor load of concrete and steel decking (assumed 45 psf and 53 psf, respectively, may be off by a few pounds) plus the design live load of 40 psf (no live load reduction). These beams frame into the Column FF.1. These beams carry almost 2000 lbs per foot from spans that are 27'-9 1/2" and 26'-2 7/8", for a total of 3862 lb/ft. Assumed that construction materials in place on October 12th are approximately equal to design loads, or that the floors would have eventually seen AT LEAST these design loads.
(4) The column FF.1 at Row 10.2 carries a total design load of 60.6 k from Floor 16, 60.6 k from Floor 17, and 52.1 k from the "Roof" for a total of 173.3k.
(5) With the 40 psf applied load on the 16th Floor & 17th Floor and 20 psf for the roof (I remember seeing a higher design load for at least parts of the roof, but I cannot find that information today; in any case, this was a part of the roof that was blocked off from guests' use), the W16x26 has the following Critical Stress Ratios:
Bending 1.342
Combined Bending 1.477
Shear 1.855

I haven't checked the bolts for this beam's connections yet.

This would indicate that the poor W16x26 will fail in shear, though as I mentioned above, the connection of the beam in Col Row BB at the Rampart St facade, also a W16x26, almost certainly failed first, as it carries load from TWO of these W16s.

Of course, we still have to say, "This was only the Permit Set. The For Construction drawings in use may have been revised", but I think the area identified is the initiation of failure for this building.

I can scan and send my sketches and notes for this analysis later. I suppose it's only fair to redo these calculations with the appropriate Live Load Reduction, but I don't have time to do that now.

What do you guys think?

RE: Hard Rock Hotel under construction in New Orleans collapses...

I've always thought these transfer beams were the root of the problem.
See my post on 16 Oct 19 20:06.

RE: Hard Rock Hotel under construction in New Orleans collapses...

As pointed out by dold (16 Oct 19 22:40), it appears the transfer beams are actually at level 16, not 15.

RE: Hard Rock Hotel under construction in New Orleans collapses...

NOLAscience - I don't think you can assume the full 40 psf LL when looking at collapse, we don't know what actual load was on the beam but if it fails on the DL then that would be a strong indicator of the cause (maybe one of many).

Building on what you have in your post I looked back at the connections in the permit set. The permit sets notes delegated design except where designed in the drawing set. The drawing set shows all shear plate style (S3.14), I recall seeing some pictures showing a shear plate so I assume this was the style used.

Looking at S3.14 for W16x26 shows a 4 bolt (3/4" A325) with 1/2x4 plate and 3/16" weld. ASIC 14th page 10-110 for this configuration doesn't show a load for STD hole 1/2" plate but SSLT 41.5 kip but weld is 5/16" - drawing shows only 3/16" weld. 3/16" weld is only shown for 1/4" plate where connection capacity is 34.8 kip. So actual connection capacity is somewhere between 41.5 and 34.8 kip - ASSUMING actual connections followed permit set Typical.

If I take your 173.3 kip column load and multiply by 0.6 (rough estimate of DL only) that is 104 kip, assume 1/2 to each end of the W16 is 52 kips. Connection at best 41.5 - so connection failure. A connection failure also explains the sudden collapses. A beam overloaded would probably deflect a lot and then yielded instead of suddenly fracturing. Where a connection would tend to fail suddenly as bolts ripped out, weld broke or some other failure mode.

*** Edit ***
I saw a YouTube video showing a beam with two rows of bolts. I assume it was an extended shear plate connection so at least that connection was different than the permit set connections I discuss above. It would be nice to see the final shop drawing set but at this time my evaluation above may or may not be an accurate description of the actual connection.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I gave up on running numbers based on the permit set of drawings since the photos show many differences between the drawings and actual construction.
The slabs seem to be thicker than the 5.5" shown on the drawings, and the transfer beams appear to be supporting one additional floor and the roof as opposed to two additional floors and the roof.

I do think the transfer beams/connections are the problem, but we probably can't run the actual numbers based on the information we have.

RE: Hard Rock Hotel under construction in New Orleans collapses...

He replaced it with this one, which has a couple of corrections, but still some errors I need to point out to him:
https://www.youtube.com/watch?v=8IJ17QkMVmA

Unfortunately, because he made yesterday's video private, we have also lost most of the comments from that video. I have a few screenshots, without the hidden replies.

Due to the transfer framing being at the 16th Floor, not the 15th floor (but, note that the roof load I am using is quite low compared to the load from the added enclosed rooftop bar), revise the Total point load from 173.3k to 112.7 k (DL 84.0k), and reactions to Rleft = 47.7k, Rright = 65.0k.

I see the Shear Stress Ratio as 1.209 with V)allow = 54.0k. Again, that is with the Design Live Loads.

DL is 77% of the total load in my (original) 2 floor and roof loading; it is 74.5% for the (corrected) 1 floor and roof loading. Compare my DL only beam reaction of 48.4k to ldeem's calculated connection capacity of between 41.5 and 34.8k.

Remember, this isn't even the worst beam/girder AND we don't know if the beams were revised at the same time that the newer set of architectural drawings were released (May 2019). If I were sure these were the beams used, I would calculate the reactions for the worst beam/girder in Col Row BB. I think IceNine is correct, we have to get the FINAL For Construction set.

RE: Hard Rock Hotel under construction in New Orleans collapses...

NOLAscience
Do you have a link to the security camera footage that you refer to?
Re: "I kept wondering when we would see security camera footage."

RE: Hard Rock Hotel under construction in New Orleans collapses...

2

Quote (GPR_Tech)

NOLAscience
Do you have a link to the security camera footage that you refer to?
Re: "I kept wondering when we would see security camera footage."

Here it is:
https://www.youtube.com/watch?v=71-fFPHnlrQ&li...

He went back and played the first indications of the floors falling (at least two, following the same pattern) in the now "private" video. Go to 7:30 in the video, then press the "." key on your keyboard and keep tapping it until you start to see the failure. The "," button plays the video back, frame-by-frame.

This video was taken by a security guard or similar person in a nearby hotel of the playback of the security camera footage using his/her smartphone, so that's why there is a bit of jiggle to the image.

RE: Hard Rock Hotel under construction in New Orleans collapses...

After watching some YouTube videos showing double row of bolts on a connection I have to correct my earlier post. The permit plan connections do not seem to be the standard connection used in the final design.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Re: "A news item about concrete strength vs. removal of temporary shores at the hotel"

I'm not saying that the temporary shoring should have been removed when it was in this case.
But, what the headline failed to mention is that temporary shoring or formwork may be removed based on concrete strength testing and Engineering approval. In my experience this is the common practice.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Does not sound like it matters anyway. This structure appears to be an engineering disaster. The shoring removal simply expedited the process.

RE: Hard Rock Hotel under construction in New Orleans collapses...

GPR Tech,

Quote (GPR Tech)

But, not mentioned in this article is that temporary shoring or form work may be removed based on concrete strength testing and Engineering approval. In my experience this is the common practice.

In the article it states:
Usually, when post shores can safely be removed depends on testing of the concrete in a lab, which measures how much pressure is required to break it. The tests are to be run three days, seven days and 28 days after concrete is poured.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (JAE)

A news item about concrete strength vs. removal of temporary shores at the hotel:
https://www.nola.com/news/article_64e1c72a-fcf3-11...

There's a lot I disagree with in that article.

For one, ACI 347 doesn't really apply to this case. That's a formwork guide. Upper floors were steel framed with slab on deck. Formwork removal guidelines (not rules, again 347 is a guide) don't really apply here. The proper standard to follow is ANSI/SDI-C1.0, which is for composite floor deck and available to download for free on SDI's website. The current version of that standard requires shores (if used) to be left in place until concrete hits 75% strength. A user note says typical practice is to also leave shoring in place for 7 days, but that's not a requirement.

For two, even if they did remove shores early, the main consequences of ignoring formwork removal times once the concrete has hardened is typically deflection and cracking, not catastrophic failure.

For three, the article says its source is a steel worker. While I guess it's possible for steel workers to be familiar with formwork guidelines, I'd consider it a little unusual. Going the other direction, you wouldn't expect the guys placing concrete or laying block to be familiar with AISC's Code of Standard Practice.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Does LA have inspection requirements for threshold buildings? If so, it is hard to believe that the apparent issues with out-of-plumb shoring, damaged post shores, sagging decks, post shores being forcibly removed under load, undersized beams, and poor cantilever configurations were not caught by the threshold inspector (engineer).

RE: Hard Rock Hotel under construction in New Orleans collapses...

LADBS was supposed to inspect and accept it.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Saying 347 is not applicable is not correct. SDI-C1.0 references ACI 318, which references ACI 301 which references ACI 347 to give the designer more information regarding the behavior of formwork, which includes shoring and reshoring. I have not yet found an SDI reference that provides insight into recommendations for shored deck construction - meaning actual methods for shoring props and the like, so heading back to 347 is my typical plan.

The direction of the SDI standard that the only consideration that must be made is that shoring of composite deck remain in place until 75% f'c is attained can be rather short sighted if loading other than the self weight of the structure is involved - hence the value of a guide document that exists to inform the user about a range of options that need to be considered, rather than a minimum prescriptive code that directs a minimum outcome within noted limits - the standard is adequate for the direct components of the decking, but lacks depth in the erection portion for shoring guidance.

I'm likely biased - I'm a member of the 347 committee as well as 301, but a certain reality in this tragedy is that if we all don't understand how loadings are applied at early ages of our structures and how those loads should be released, we can certainly find ourselves having overloaded a structure.


While yes, early removal of active shores (shores under the freshly or most recently placed concrete) is likely to cause issue only with the structure directly above, removal of the lowest level of reshoring prior to releasing the loading applied by the active shores will lead to a portion of the structure carrying more load than intended.

For all the videos I have seen, I still can't point to an exact point where it all starts.



RE: Hard Rock Hotel under construction in New Orleans collapses...


While I agree with much of what DTGT2002 said above about what is applicable to steel decks, I do not consider a reference of a reference of a reference be a reference. When a building code references a standard, such as the Florida Building Code, it lists the references in a specific section. We do not then follow that reference, and all the others in that section to infinity.

There may be wisdom and guidance in the references of references, but forensically, we cannot use them in analyzing what was required in a structure when analyzing a failure. I know Louisiana has a different system of laws from the rest of the Country (really!) and that may affect how things are done.

The various officials and others are now "making news" as it seems to happen after all disasters such as this until the facts are known. Their announcements should be taken with a grain of salt until the building is thoroughly explored by engineers and necessary analysis done on the real structure.

I personally have given up on analysis of the permit plans. There are too many failure areas clearly seen as discussed in this forum and many differences have been seen in the photographs.

Any thoughts?

Regards,

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (Mojojhon)

...I do not consider a reference of a reference of a reference be a reference.

Clearly we need to see the contract documents, but
yes in many specification there are numerous reference of a reference to chase...
i.e. Specifications for Structural Concrete ACI 301 sends you to Mold and cure three cylinders from each sample in
accordance with "ASTM C 31" and so on...

RE: Hard Rock Hotel under construction in New Orleans collapses...

We should be careful here in a distinction between references that are made part of a specification by incorporation by reference versus those that are referenced in commentary or other non-mandatory means.


I was not claiming that any and all references are somehow enforceable simply by reference - but those in non-mandatory references are there to inform a reasonable engineer of available resources.



RE: Hard Rock Hotel under construction in New Orleans collapses...

I recall that the old FL building code had a list of reference documents and also included a statement to the effect that only the explicitly quoted excerpts were meant to be enforced, not the entire document.

I suppose lifting quotes out of their immediate context has its own issues, but perhaps it is better to be minimalist and incremental rather than reference a document that might not be written in consistent and enforceable language.

Edit: And yes, the contract documents can add most any requirement, no matter how arbitrary or contradictory.

RE: Hard Rock Hotel under construction in New Orleans collapses...

They must have gathered enough evidence, facts, etc. to conclude what happened and why.

RE: Hard Rock Hotel under construction in New Orleans collapses...

An ACI Guide (like 347) is just a guide. No contractual weight. None.
You don't have to be a committee member to read and understand the front page of any ACI Guide, which says "Reference to this document shall not be made in contract documents..."
In addition, the behavior and construction practices for metal deck permanent formwork are distinct from concrete formwork, so as good as ACI 347 is, it's relevance to this project's steel framing is negligible.
As MrH noted, it is unlikely that the failure was initiated by early removal of shores.
Just based on the photos in this thread, there were fundamental framing problems.

RE: Hard Rock Hotel under construction in New Orleans collapses...

"An investigation into the cause of the collapse is ongoing. Evidence will be gathered once the building is brought down, McConnell said."

RE: Hard Rock Hotel under construction in New Orleans collapses...

That seems strange....seems like evidence will be altered or lost once the building is brought down.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote (StrucDesignEIT's article)

The implosion will coincide with the College Football Championship being hosted in New Orleans on Jan. 13 at the Mercedes-Benz Superdome. McConnell said the implosion could be slightly delayed because of the game, NOLA.com reported. https://www.foxnews.com/us/hard-rock-hotel-new-orleans-imploded-bodies-recovered

Is it me or does it seem like the city has just decided to cash in on this disaster? Is anyone else reading into this the same as I am? First the crane demolition spectacle, now we're scheduling the implosion for the same weekend as this football game? Seriously?

Then there's the "Evidence will be gathered once the building is brought down." Seems like the least they could do is fly some drones through the mess. Hell, some people already have, or at least close enough to provide a fairly good picture of the ruins. Just fly this bad boy around each floor. Better than nothing...

RE: Hard Rock Hotel under construction in New Orleans collapses...

My guess is that they have done all the investigation they feel like they can SAFELY do, so anything else comes later.
Also, they had those braces bowing and stuff prior to the collapse, so they may have a pretty good idea of what went on already. "Investigation" in this case may just mean checking materials to confirm they are not faulty, etc.

RE: Hard Rock Hotel under construction in New Orleans collapses...

I agree with JStephen - they probably identified the root cause as a design error.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Quote:

Quote (Rabbit12)

Celt83, I presume the entire company can't work on this one project since I assume the firm also has other projects. The size of this project and the size of the structural engineering company seems a little disproportionate. I'm sure it's possible to complete with a small team like that but there are also other projects, marketing, etc. that must happen. I'm guessing this project really taxed that firm.

Yea, after checking out their website, looks like two PE's, and EI intern and a bunch of drafts-people.
Seems disproportionate in general and excessively so for a project of this scale.

RE: Hard Rock Hotel under construction in New Orleans collapses...

Is there a requirement that all the design resources must be organic to the bidder? Companies often hire additional resources to handle excess loads and slough them off once done. There are lots of freelancers that work on short-term contracts.

TTFN (ta ta for now)
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RE: Hard Rock Hotel under construction in New Orleans collapses...

"An investigation into the cause of the collapse is ongoing. Evidence will be gathered once the building is brought down, McConnell said."

This may just mean that ADDITIONAL evidence will be gathered once the building is brought down. In other words, don't expect the debris to be hauled away by February 1st.

RE: Hard Rock Hotel under construction in New Orleans collapses...

2
See every fourth post above for all disclaimers about not blaming anyone yet. I second these type statements and want to say that before I say what follows.

I own a firm about the size of the structural firm in question. I've never designed a building this size, but fully believe we could. If a project this size presented itself, the very first thing I would do would be to bring the project to a colleague who owns a much larger firm that routinely handles projects this size. I would ask his firm to be the EOR, but let my firm gain some experience by outsourcing calcs and drafting under his DIRECT supervision. That's my initial thought and he might not even go for that. I often run hypotheticals in my head. :)

Point being, we have to stay within our limits of experience and not make quantum leaps.

In following this disaster, I can say that it has strengthened my resolve to remain diligent in my work product. We can become a bit over confident as engineers. When you have designed well over a thousand buildings during your career and never had an actual structural issue, being overly confident can be one result. Almost a feeling that your building can't collapse. I've often wondered how far we could, in reality, take our designs and have no issues (how much over-design is really there).

Every one of us can learn some lessons from this. There will be many to be learned as all plays out over the next year(s), but I guarantee there will be a lesson here for each and every one of us. Even if it is something as simple as don't view yourself as superior... and even listen to the immigrant worker/laborer on your project.




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