"Doomed" Las Vegas Tower - Structural Blunders
"Doomed" Las Vegas Tower - Structural Blunders
(OP)
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
Download nowINTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS Come Join Us!Are you an
Engineering professional? Join Eng-Tips Forums!
*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail. Posting GuidelinesJobs |
"Doomed" Las Vegas Tower - Structural Blunders
|
"Doomed" Las Vegas Tower - Structural Blunders"Doomed" Las Vegas Tower - Structural Blunders(OP)
Red Flag SubmittedThank you for helping keep Eng-Tips Forums free from inappropriate posts. Reply To This ThreadPosting in the Eng-Tips forums is a member-only feature.Click Here to join Eng-Tips and talk with other members! |
ResourcesThe world has changed considerably since the 1980s, when CAD first started displacing drafting tables. Download Now
Prototyping has always been a critical part of product development. Download Now
As the cloud is increasingly adopted for product development, questions remain as to just how cloud software tools compare to on-premise solutions. Download Now
Engineering-centric businesses face a number of challenges today, but unmanageable design and change processes don’t need to be counted among them. Download Now
|
RE: "Doomed" Las Vegas Tower - Structural Blunders
Dik
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
The steel erectors should have notified the general contractor, who wouold have thus notified the structural engineer and maybe something could have been worked out, rather than just not istalling the steel anchor supports.
And shame on the third-party inspection company for falsifying all of those reports. Sixty-two falsified reports, where one falsified report is unacceptable.
However, this will be backlashed onto the structural engineering company, and the argument is going to be that they supposedly never visited the project site to perform simple progress check-ups.
All-in-all it will be interesting to see how this whole thing gets resolved.
RE: "Doomed" Las Vegas Tower - Structural Blunders
In 34 years, I have yet to find a flawless construction project.
This one will be litigated for a long, long time.
Thanks for the post, JAE.
RE: "Doomed" Las Vegas Tower - Structural Blunders
http://www
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
ANY FOOL CAN DESIGN A STRUCTURE. IT TAKES AN ENGINEER TO DESIGN A CONNECTION."
RE: "Doomed" Las Vegas Tower - Structural Blunders
I guess it's okay that this negligence has only cost a property developer a couple of hundred mil US, but this could have cost someone their life.
RE: "Doomed" Las Vegas Tower - Structural Blunders
I do agree with your statement, but unfortunately that could be perceived as a conflict of interest on some level. Especially if you have to follow Chapter 17 of the IBC, a third-party "special inspector" is required.
kikflip,
Unfortunately, the ones who will get the brunt of it will be the structural engineer and the general contractor. Most third-party inspection companies aren't really large enough to provide some sort of back-pay and face any level of fines...and usually fold right away to cover the inspector's owners and professional engineers...if they even have any professional engineers on staff to oversee the inspection crew.
Just my general opinion on this whole matter.
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
I don't believe there to be a conflict of interest. I don't think that we structural engineers are so negligent that we will let something slide by just because we are also the engineer-of-record. If there is a team of people that know the project inside-out, it is the structural engineer.
We do a lot of our own inspections in South Florida on Threshold projects. Our office policy is such that the person who designed the project (project engineer) is not the person doing the inspections. The inspector is someone within our own office (an EIT with 2-3 or more years of experience) who has strong engineering knowledge but no project knowledge. The goal is to inspect what is on the drawings and also sometimes to question "suspect" details and discuss it in the office.
I believe we strive to make our structure as safe and as constructable as possible. It also helps the project go smoother because there is always a direct line of communication between the "design team" and the "inspector" which is not often the case when you have "third-party" inspectors who have to follow round-about protocols to get problems corrected or questions clarified.
Enough of the rant, IMHO I think the third-party inspections is bogus.
RE: "Doomed" Las Vegas Tower - Structural Blunders
I see no conflict of interest for this type of thing - we are not awarding contracts only ensuring that the building is safe. If it is safe no problem, if it is unsafe then it is the engineers door that will first be knocked on.
I am a strong advocate of the person who designs the building doing the inspection for a couple of reasons.
Firstly, it gives a direct route for important feedback and learning. How is a graduate engineer expected to get an understanding of what works or doesnt work on site unless they are involved in the inspections.
Secondly, there is no such thing as a perfect design. Any flaws are much more likely to be picked up on site by an educated pair of eyes that understand the way the building is designed to work.
Lastly, they are probably the most appropriate person for the job.
RE: "Doomed" Las Vegas Tower - Structural Blunders
In my experience, complex details need to be worked out at the design stage and sometimes the design intent may not be clear to a contractor or an inspector (3rd party or not) who is not intimately familiar with the intent of the details. I have witnessed how much work has gone into complex rebar layouts at the design stage with 3D models and such to try and assess constructibility. There have been instances I have been involved where contractors and inspectors, under the pressure of time and $$$ (or through lack of training), make subtle field modifications, that on the surface appear reasonable, but create conflicts with the original design intent. I am a big fan of keeping the EOR informed of ANY design changes in a timely fashion. Sixty-two falsified reports is totally unacceptable and misleading.
RE: "Doomed" Las Vegas Tower - Structural Blunders
The VP of the Special Inspection firm has had his license suspended by the State of Nevada. We've worked with them, as a Geotechnical Firm, extensively. I've met him. He's a good man and a good engineer. I'd sure like to hear his side of the story.
RE: "Doomed" Las Vegas Tower - Structural Blunders
I will say that communication is key and it is imperative that inspector qualifications be reviewed by the owner and design team.
I'm not totally opposed to third-party inspectors as they have been very helpful and the special inspection process can be very time consuming. The third-party guys that I have worked with have been very active in the problem solving process when issues arise and I have learned a lot from them and the contractors for that matter.
RE: "Doomed" Las Vegas Tower - Structural Blunders
From personal experience, whenever I have a third party inspector on one of my jobs, I almost never get any calls from the field or comments on the reports that they found anything to be non-conformant. When my own people do these inspections, I get multiple calls every week asking if something is OK, or if something needs to be fixed.
Sophisticated owners recognize the value of having the inspector work for the EOR, but all to often, they see the bottom line and go with the low-ball number. Many just don't understand the impact of using an un-certified concrete tester as their inspector.
Perhaps projects like the one highlighted in this thread will wake some people up- but I doubt it.
RE: "Doomed" Las Vegas Tower - Structural Blunders
Garth Dreger PE
AZ Phoenix area
RE: "Doomed" Las Vegas Tower - Structural Blunders
And why would a steel structure ever need to be demolished if there are structural problems? You can modify a steel structure in an infinite amount of ways once its built, I imagine at a fraction of the cost of demolition and rebuilding.
Special Inspection- Though I like the idea of in-house special inspection (done by the EOR), that is not always logistically feasible. If the project is 2+ hours away and you are a one or two man SE firm, occasional observations may be the only service you can provide. Second, many E and O insurance policies specifically exclude INSPECTIONS without a modification to your policy.
RE: "Doomed" Las Vegas Tower - Structural Blunders
The structure in question is CIP concrete. The deficiencies were in rebar.
RE: "Doomed" Las Vegas Tower - Structural Blunders
But I suppose rebar is steel now isn't it...
Carbon fiber maybe?? A whole lot harder to know exactly the field conditions when they are covered with concrete!
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
Some of the "late" implementations such project managers and third party inspections may be -not neccesarily are- truly invasive and disruptive of the traditional ways, particularly in chain of command and some aperture to the "politics" and "economics" of getting commissions, fees, etc.
Not that this only happen to designers; european contractors may be forcibly required to bring the financing of big works or maintenance of the same for say 20 years, making the bank an uninvited guest to their dish.
I am wary of such aperture that can turn in a field of mines able to do away with entire sucessful, profitable and responsible practices and firms, and I have seen cases where these purportedly neutral interventions, and maybe protective of public interests, lead to the realization of the dangers above stated.
Particularly worrying is that some of the outfits are (sometimes transparently, i.e, "invisibly") manned by cheaper scarcely trained professionals, or even if trained, with so little practice or common sense that they themselves are a risk; everyone that can punch the cards, er, make the input to some program is already the nicest engineer.
In many cases, 3d party intervention is a logical requirement, and not even such concern as Foster's can think be logical to take it all to make something in Las Vegas in accord to customs and laws they are not customarily practicing (something entirely common for international practice except for delivering ready-made facilities, I think). Hence some must decide that from construction design and later they just better look from the distance. And sometimes must be a sight.
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
"Perini counters that structural drawings for Harmon 'were months late and contained many errors and omissions,' adding that MGM Resorts 'would have to acknowledge that the permitted set of drawings never matched the sets of drawings (used) to construct the project.'"
Was this project so rushed that they didn't have drawings to build from?
I think that MGM found out in the middle of the project that it was going to be a money loser. They're litigating their way to cover part of their investment.
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
ANY FOOL CAN DESIGN A STRUCTURE. IT TAKES AN ENGINEER TO MAKE THE CONNECTION."
Dik
RE: "Doomed" Las Vegas Tower - Structural Blunders
J, you received a star. You have made a very good point and I thank you! To be honest I assumed that the act of fraud and misrepresentation had taken place. Is this a fact or am I jumping to the wrong conclusion? Could the inspection have inadequate because of inspector ignorance or inspection criteria the inspectors are reporting to? Should I believe newspaper reporters as always correct who have verified their statements and context to avoid slander?
JedClampett, I gave you a star also. Yes, there are 2 sides to every story. It is usually the good ones that die first.
What are the requirements to become an inspector, how are the inspectors qualified, who qualifies the inspectors, who is overseeing the inspectors? What was the inspection criterion and did it include the issues deemed unacceptable?
I have a hard time believing that reporting errors (intentional of unintentional) where made by that many inspectors and everyone turned a blind eye to it. There is usually a whistle blower in the pack. Perhaps this is how the condition came to light and the whistle blower is now included in the Las Vegas 20% unemployment stats pointed out by DIK.
IMHO, fraudulent, intentional, misrepresentation of inspection results should be punishable by law, include a fine and jail time. Punishment should also be extended to the entity paying and employing the liar. I say this but on the other hand I do feel for inspectors who have a family to feed and want to do the right thing but are pressured or mislead otherwise.
RE: "Doomed" Las Vegas Tower - Structural Blunders
I don't think you are crazy.
RE: "Doomed" Las Vegas Tower - Structural Blunders
And you get a star because I love your music!
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
http://www.fox5vegas.com/news/25805385/detail.html
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
We used to build physical models of some congested joints in a couple of the nukes that I worked on. It made planning the rebar installation so much less difficult.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: "Doomed" Las Vegas Tower - Structural Blunders
While it doesn't quite sound like the structural engineer is completely off the hook here, there seems to be a lot of overwhelming evidence that the rebar sub and the inspectors were the major culprits here.
How this went on for 15 floors of construction is beyond me. Did the EOR not made a single pour visit the entire time? I understand sometimes you are specifically not hired to perform construction administration. However, on a building of this magnitude, an engineer should never allow complete separation from the construction process.
Oh well, at least it was a successful project for the lawyers.
RE: "Doomed" Las Vegas Tower - Structural Blunders
Then, after the lawyers and the insurers became involved, we were instructed to stay away from means and methods, it belonged to the Contractors and our insurance didn't cover it. The weird thing though, was that one of our construction managers would look it over for an independent QA constructability review. Unfortunately, they were senior, desk-bound guys who hadn't been in close proximity to actual construction work for eons.
Oops, this started out as a caution, the GC says they were working to drawings different to the sealed permit set. We don't know if the EOR was consulted about the changes. We don't know what drawings and documents the Inspectors were using. It looks certain that the owner miscalculated the demand for condos and is trying to call it a loss due to the faulty work, etc. etc..
A personal note; I hated working on jobs implementing the designs of "Great Architects".
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: "Doomed" Las Vegas Tower - Structural Blunders
Considering the terrible housing and construction market in Las Vegas, and without saying which parties were at fault, how could anyone expect the above situation to end well?
RE: "Doomed" Las Vegas Tower - Structural Blunders
A star paddington! - I've seen the same frustration - but that struggle is either because:
1. The "great" architect was really quite incompetent when it came to constructable details, or,
2. The "great" architect was designing something unique, and in doing so was pushing the engineers to stretch their designs as well and design something unique as well, or
3. a combination of 1 and 2 above.
RE: "Doomed" Las Vegas Tower - Structural Blunders
With hundreds of millions of dollars at stake, I wouldn't mind getting a cut of it to do an as built analysis of the structures. It seems that tearing them down is pretty drastic. Fifty or sixty million dollars in repairs could go a long way.
RE: "Doomed" Las Vegas Tower - Structural Blunders
The nomenclature used in those articles is "link beams". I don't know what that is, although I suspect they could be core coupling beams. If that is the case, both shear and moment are high, and the placement and spacing of the bars is critical. One of the articles also said that the issues with the building are well known in the structural engineering community worldwide, but I must have missed it. Anyone?
RE: "Doomed" Las Vegas Tower - Structural Blunders
Yep, that was my interpretation as well. In one of the articles I read, they stated that the mistakes had implications on the lateral stability of the building.
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
Dik
RE: "Doomed" Las Vegas Tower - Structural Blunders
How much pencil sharpening room is there for tall structures like this?
At our company we work on smaller scale projects and the majority of the calcs are done by hand and thus there is usually room for some pencil sharpening. However I don't have much experience on tall structures such as this, where I'm guessing the design was computer aided. Is there typically still some room for "pencil sharpening"?
Thanks
EIT
RE: "Doomed" Las Vegas Tower - Structural Blunders
They were involved with the Millenium Bridge in London. The lead consultant was the engineering consultant Arup who asked Foster to get involved with the design. Suddenly Foster muscled their way up to being lead consultant. When the bridge opened there were serious problems with dynamics from irregular foot fall and the footbridge was swaying all over the place. Guess what happened next - Fosters decided they were no longer the lead consultant and handed the job back to Arup.
Sophistocated dampner costing £5 miilion fixed the problem. Foster was nowhere to be seen.
RE: "Doomed" Las Vegas Tower - Structural Blunders
Rule #1 - If something is complex you must perform some spot inspections especially early in the project
Rule #2 - Don't get involved in hotels, time shares, or condo projects. All parties are low bid and thus no one is doing their job completely. This includes the architects, the engineers, the contractor, his subs, etc... Lawsuits always are the result. I knew an engineer in Florida who was doing timeshares and hotels for less than $8000. I saw one up in lake city that didn't even have a structural engineer. Needless to say the trusses are tied to the light gage curtain walls but the walls are only anchored with a few tapcons.
Rule #3 - Place a note on your plans that you were perform period observations.....but inspections are not your responsibility etc, etc...
Rule #4 - Make sure you have insurance
Rule #5 - Stay away from the cheap people.
Rule #6 - Start spreading the word around on bad engineers and inspectors. Don't be shy. For years I would stay out of that sort of thing. But there are too many firms doing really bad work. Don't be afraid to call them out. I had an architect once who gave me some load tables for some SIPS panels. I saw who the engineer was and told the architect we had better take them with a grain of salt. Sure enough about a month later he was written up yet again by the board of engineers.
Rule #7 - You do know that most truss engineers are plan stamping. If you see anything that doesn't jive with your plans reject them. Reject them over and over again until you get the truss engineer to actually look at your plans. Most of the time they seal those plans and they've never even seen the contract drawings or even the required loads.
Rule #8 - Even the contractors that seem to care, or have a good reputation, even the ones that go to church really only care about the budget, the schedule, and the finish. Sure they don't want it to fall down right away. But unless they've seen damage from the eye of the hurricane trying to explain to them the wind load path will cause their eyes to glaze over and their hands to guard their wallets.
Rule #9 - Consider working for the city or state so that you you can make and engineer's salary, sleep and night, get 8 weeks vacation a year, every holiday under the sun, and a big fat pension. Oh yeah and you won't have to do anything.
Rule #10 - In this slow economy contractors want to build even faster than before. All projects are now fast track. Fast Track means we are going to build so fast that nobody can keep up with all the mistakes we are going to make.
Rule # 11 - Masons these days equals person that not even Walmart wants to hire. This design all walls with bars in the center of the cells. Anything else will be much too difficult for them to do. Trust me they won't get it right and they will exhaust any inspector who tries to get them to do it right.
Rule #11 - Simcon tilt-wall will put the wrong size chairs in their tilt wall panels every time. In fact they will ship only one size chair regardless of how many panel thicknesses you have on a project.
In general I don't like to tattle tale, but its just gotten to be too hard to stomach the mess we call construction. I've always felt like if I am going to do something might as well do it right. It doesn't take that much longer. I just can't understand why people don't take pride in their work anymore. Perhaps its always been this way. But it seems like its harder and harder to find accurate plans and drawings. Construction is even worse. For all the advances we've made in computers, CAD, codes, and over all knowledge its being offset by poor workmanship.
Sorry I needed to rant a bit.
John Southard, M.S., P.E.
http://www.pdhlibrary.com
RE: "Doomed" Las Vegas Tower - Structural Blunders
In my opinion, periodic structural observations (which can only be performed by an RDP) probably would not have been sufficient to catch a major blunder like this. I am almost certain if a PE from the firm had served as a resident special inspector, the non-conforming items would have been detected early on.
One thing many may not recognize is that structural engineers in the west coast are not permitted to perform special inspections (which include rebar inspections) unless they are ICC certified inspectors. Very few SEs/PEs bother to get certified and hence rarely offer special inspection services.
On the east coast, many jurisdictions permit PEs and RAs to perform special inspections without the need for certification. So it is not uncommon to come across solo design engineers on the east coast who also perform special inspections on their projects. I wonder who contractor personnel would pay more attention to when a non-conforming item is pointed out, a certified special inspector or the PE who was responsible for the design?
Clark County NV has one of the best special inspection programs in the country. Coupled with a powerful quality management system with well thought out checks and balances, they have a competent staff of special inspectors who conduct inter-alia, audits on the work of third party special inspectors. Yet still, these non-conforming items were not caught. Makes me wonder whether the county inspectors or third party special inspectors even comprehended certain aspects of the structural drawings on this project. In fact it should not surprise the SE if the typical special inspector does not comprehend complex structural drawings. If the designer determines the drawings will be complex, it is in his/her interest to have several meetings with the special inspector(s) assigned to the project to elucidate the drawings, particularly clarification of complex details.
In some building codes, the responsibility for approving the special inspector lies with the SEOR. LA City BC and NYC BC come to mind. I think this is a good idea. Not sure whether the SEOR approved the inspectors on this project.
I may have zoomed past it in reading (read it twice)...but does anyone know how the problems were first detected?
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
RE: "Doomed" Las Vegas Tower - Structural Blunders
There was a push to change state laws nationwide to force EOR control at all stages of design and construction. The construction lobby went to work and since there were no more disasters for a while, it was quietly dropped.
h
http://en.wikipedia.org/wiki/Kemper_Arena
http://en
Oh I forgot one, the Hartford center.
http://en.wikipedia.org/wiki/XL_Center
At the time, I worked for the engineers/CMs for the work at Willow Island (Pleasants Power Station) except that the cooling tower was a separate contract, not included in our work. I had worked on the design of Pleasants Power Station there for several years.
ps. What would you think of a law that required EOR participation/approval though all stages of the work? I see some of us wrongly interfering with means and methods.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: "Doomed" Las Vegas Tower - Structural Blunders
Isambard Kingdom Brunel would approve.
He'd probably demand it. ... and get it.
Mike Halloran
Pembroke Pines, FL, USA
RE: "Doomed" Las Vegas Tower - Structural Blunders
In regards to your question about pencil sharpening, I think it is difficult to say. I have worked on several high rises. In my experience, it is often the case that significant structural design work is done concurrently with ongoing architectural design. In this way, initial structural designs are developed and refined, over multiple iterations into the final building. Ideally, the initial structural design will be conservative, and the architectural revisions small enough that the final design is efficient, but not necessarily pushing the absolute limit. However in some cases, large or unanticipated architectural revisions will require the design to be pushed to its limits. I would not call the design unsafe, but in a case like this, there wouldn't be much wiggle room, if it was already designed with the sharpest pencil.
To give an example, things like column layouts and slab thickness may be set fairly early on, and the design and cost implications of increasing the slab thickness, by even as little as 1/2", on 40+ floor slabs, will make an engineer more likely to look to up the reinforcing to its limits.
Another example, changing a single beam W18x35 to W18x40 on a one story project normally is of little concern. However, if you change 10 such beams, on 40 floors, you've changed 400 beams, and the cost increase is significant enough, that you might be willing to accept the W18x35 designed right up to its allowable limit.
RE: "Doomed" Las Vegas Tower - Structural Blunders
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: "Doomed" Las Vegas Tower - Structural Blunders
I have been an engineer in Florida my whole 13 year career and don't disagree with any one of your rules.
I love doing engineering and being a structural engineer, but the business side of things, and the construction admin portion of the projects will make you question yourself why you do this sometimes... But hang in there, you sound like one of the good ones.
And usually I only stop in Lake City for gas or food but I will steer clear of any hotels.
It'd also be nice if the FBPE would do more than have a hearing and then make a guy take a class and pay a $1000 fine.
And to become a threshold inspector in Florida you have to work under one for 3 years (in addition to having your PE license). I would get my license and do this kind of work if those rules were different, and I think I'd be good at it. I sure would bust some balls. Maybe they should offer a class or something. I have to think a lot of engineers are just getting other engineers to fill out their paperwork, wink wink...
RE: "Doomed" Las Vegas Tower - Structural Blunders
Sad, but true.
RE: "Doomed" Las Vegas Tower - Structural Blunders
In Arizona, one of the skills they teach in prison is blocklaying.
I mean, I like everyone to get a second chance, but doesn't that tell you something?
RE: "Doomed" Las Vegas Tower - Structural Blunders