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What's Going On In Texas? Part 2

What's Going On In Texas? Part 2

RE: What's Going On In Texas? Part 2

Wouldn't want to be that Geotech!

RE: What's Going On In Texas? Part 2

Cheesy comment Ron.  Sounds like the issue is settled.

Mike McCann
MMC Engineering

RE: What's Going On In Texas? Part 2

I've worked with that geotech firm some years before and they were a good bunch.  Probably one of the top firms in San Antonio.

 

RE: What's Going On In Texas? Part 2

It sounds to me someone wanting to get rid of some unsaleable condos and other pay, even on the huge settlements present. The crisis. Will be more.

RE: What's Going On In Texas? Part 2

It doesn't matter if the geotech was right or wrong....there appears to be a significant indication of settlement, so the geotech is in a defensive position, right or wrong....must prove his point.  That's expensive.

If I were the attorney for the Geotech and structural, I would file an injunction to prevent the demolition....once it's done, there's no going back and part of the evidence is gone.

RE: What's Going On In Texas? Part 2

Anybody know what founding system was used?

RE: What's Going On In Texas? Part 2

I am with Ron in not letting it be demolished till the trial is settled and firm.

RE: What's Going On In Texas? Part 2

It's possible and often the case where the developer, designer or builder deviates from the Geotech's recommendations due to cost.

Greg

RE: What's Going On In Texas? Part 2

(OP)
Well, if the deviated from the Geotechnical Report, then the Geotechnical Engineer is not going to be as responsible. But when the lawyers are involved, you might have to defend why you didn't do anything to enforce your report.
Lesson: Always, always either execute your design exactly as the Geotechnical Report says or get a written exception from him/her when you don't.  I'm a big believer in literally cutting and pasting the Geotechnical Report requirements (with changes like "should" to "shall")into our Earthwork Specification.  That way there's no chance of a dispute. Why pay those guys if you're not going to listen to them?

RE: What's Going On In Texas? Part 2

The reports seem to indicate that they left the Design/Builder (Zachary GC) off the hook but is blaming the geotech and structural engineer. This makes no sense if the D/B controls the full pot of money and hires the geotech and SE as subs.

The D/B sometimes uses the control as a club to reduce the amount of inspection that is recommended. I wonder if the geotech had fulltime inspection of foundation installation!

RE: What's Going On In Texas? Part 2

Why would they let the contractor off the hook so early....do they have substantial evidence that it was clearly a geotechnical and/or structural issue?

RE: What's Going On In Texas? Part 2

Just wondering if the Geotechnical investigation was engaged directly by the Client, Builder OR Structural Engineer?

 

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RE: What's Going On In Texas? Part 2

Although I agree that the building should remain until the trial is over, the trial could last a very long time.  They will need to make sure the building is not or won't become unstable and possibly collapse in the interim.

RE: What's Going On In Texas? Part 2

Certainly a required reserve.

RE: What's Going On In Texas? Part 2

Some ramblings...

One has to know the relationship between the Owner, the Developer (if different), the Design/Builder (if different, the Structural Consultant, the Architect, and the Geotekkie to see who did what to who...

The structure should remain in place until it is agreed upon by all parties that it is no longer needed for info. There is a cost to this, but it's all part of the claim. There could/should be long term monitoring of the current problem and the cause of any differential movement determined.  It could be from factors unrelated to the original construction.

I often include any/all geotech reports as part of the bid documents and do *not* selectively publish parts or recommendations. On one of my latest projects, there are about a dozen geotech reports for the site going back 3 decades... the bid documents note that these are all available for review by the bidders.

Dik

RE: What's Going On In Texas? Part 2

It is curious that Dik quotes a particular identified interest in the getechnical parties not make recommendations (or so I interpret); maybe for some having been found irresponsibly assertive or restrictive? Normally, less informed structural designers on ground matters would prefer the contrary (because as above quoted complying and making to comply with the recommendations would -it is expected- clarify the responsability of whom...
yet ... shouldn't a good structural designer overcome and fight any bad recommendation by any party trying influence him/her out of required safety? I find no indemnity on this ... not even from the code itself, let me say. So I am of the opinion on that if it is me with my knowledge, firm and warrant who is to guarantee adequacy to use, safety included, codes should allow me perform to my wish.

But more modestly returning to the matter of no recommendations, someone in the spanish legislation must have identified the risk of always following the recommendations of the geotechs for the foundations for it states that recommendations will be included in the geotechnical report IF the structural designer so demands. And note, will ever remain recommendations (as worrying as they can be when not respected and in problems), so no indemnity can be expected from recommendations when one has personal professional liabilities overcoming any recommendation given.

RE: What's Going On In Texas? Part 2

Tower's core had sunk 14 to 16 inches, while the attached garages sank less than half that amount.

Why the rush to demo?

RE: What's Going On In Texas? Part 2

ishvaaag:

To clear up any confusion... I use geotech reports for most projects and use the information contained in them.  If I have an issue, then I will discuss this with the geotekkie... and any variation is in writing. I often forward a copy of the final drawings to the geotekkie (to help share the guilt <G>).

It is not often that I use design values other than recommended; I'm happy to hang my hat on his expertise.  If I feel his values for bearing are too high then I will use lower values that I am comfortable with.  My standard notes make reference to the Geotechnical report as well as a recommendation that the Contractor seek additional information.  I also usually include it as information with the bid documents.

It does open a bit of a can of worms if the contractor does a load takedown and determines that the foundations are oversized by the recommended bearing (if my design was lower), but in 40 years I've never had it happen.

Dik

RE: What's Going On In Texas? Part 2

Well, so I had misinterpreted your statement. We most than anything if something have found to disconform with geotech firms just in cases where they predict overconservative settlement, mainly; have found them amenable to the fact in such cases, and have most times managed to get it in print. It is standard practice here to include the geotechnical report as part of the overall project. And I use to ask recommendations and if not found illogical follow them. Yet in any case some parts of my arguments stand, particularly the fact that those legislating here have not seen very good the structural designers overly relying in some geotechnicar reports giving straight indication on structural types, something on which we have been (and continue being) explicitly named be responsible for in all modern legislation since Comte in the very early 1800's (I think to remember) was called to Spain to devise a Civil Code: the foundations of the buildings have been the realm of the structural designers, and even now, and in spite of the mandatory contribution of geotechnical reports, has not been seen good to relieve us of such burden. I myself prefer so, specially in those cases where I see exorbitant recommendations.

RE: What's Going On In Texas? Part 2

Sounds real fishy here, and it's not due to global warming.  

I'm wondering if the soils investigation may not have gone deep enough to discover either a very localized, highly compressible region under the tower.  Or it could be vibrations in the tower area from the construction, or otherwise, causing a quick condition under the tower.  Just conjecture though.

If the tower is just settling straight down and not leaning, what is the problem causing the need for demolition?  After all, the leaning tower of Pisa is still standing...  Just seems like the state of Texas is too swift far too often to throw the switch when it comes to eliminating problems.  

Isn't there a lot of sand in the gulf islands to contend with?  

Mike McCann
MMC Engineering

RE: What's Going On In Texas? Part 2

According to the ENR report, the building is on 95' long grout injected piles in sand, recommended by the geotech based on an investigation stopping at 100'.  Compressible clay started at 120'.  What would be the normal depth of investigation for a 31 storey, say 300' tall building?

http://enr.ecnext.com/coms2/article_bubt091007SouthPadreTo

RE: What's Going On In Texas? Part 2

According to Das 150-250ft for a 300 ft tall building, and what I use for my minimum requirements. But it would also depend on the local expectations/equipment.

I would find it unusual that this clay layer wasn't know about by the local geotechs, normally they would have a good idea of the expected conditions.
 

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that them like it

RE: What's Going On In Texas? Part 2

sorry pressed enter before the gramma check.

Arguing with an engineer is like wrestling with a pig in mud. After a while you realize that them like it

RE: What's Going On In Texas? Part 2

More ramblings.......

I am not sold on the design/build concept at this time, I think it erodes objectivity and monitoring.

I have also never been a fan of a GC hiring/paying for in feld testing/inspection.

While this mess could very well be attributed to poor geotechnical/design, I would be looking hard at construction records, quantities, weather, credentials, diaries etc.

If the guys on the ground do not exercise due diligence at all times, the geotech stuff is meaningless.
This would not be the first time I have seen folks get in too big of a hurry to do things correctly.
 

RE: What's Going On In Texas? Part 2

Do 16" diameter, 95ft long auger cast piles seem a bit too skinny to you guys?  I have done many jobs with 16" (and 14") ACP's, but never longer than about 60 or 70 feet.  95 feet seems really long to me.  Also, for a building that large, I would think larger piles or drilled piers should have been used. Personaly, I don't think I would have wanted to use anything less than 24" diameter.

RE: What's Going On In Texas? Part 2

"Datum disputes a substantial amount of the allegations in the petition..."

IE, it's hard to tell what's going on from a news story which is based on the petition filed.

The clay issue could be as simple as a statement in the report saying "There's probably a clay layer down there, we should drill deeper and find it."

RE: What's Going On In Texas? Part 2

I'm skeptical of this lawsuit. It's like throwing the baby with the bath water type of action with the demolition that they are trying to do instead of trying to engage the original designers or hiring new designers to come up with a solution to save the building.

Why? The developer's market is currently dead so going forward and finishing the project would result in more losses. Note the claim for $125M in damages instead of the amount to get the building fixed. The economics right now of the project does not make sense so for the developer, it's better to just demolish the building and claim the losses against the designers. Even the developer admitted this in the article. That's where I have a problem with. That $125M claim is probably for the cost of the construction so far and if they get awarded near that amount, the designers pretty much paid for the unfinished building and do not get to keep the building?

I can't comment about the culpability of the designers as I don't have any data to make an opinion either way but I hope the judge will order this case to mediation and see thru the developer's tactics. The defects might as well be valid but they are being used as an excuse to kill the whole project and recoup some of their investments when I think the market economics is the one driving it all along.





  

RE: What's Going On In Texas? Part 2

I used the same pile size for a 3 storey building and twice that size for a 10 storey building. Those piles adopted sounded too small in my view unless if they were spaced at every 48 inch! :)

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