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Retaining Wall Failure.

Retaining Wall Failure.

Retaining Wall Failure.

(OP)
This story is getting a lot of attention here in San Antonio.

RE: Retaining Wall Failure.

Here is part of the problem as I see it.  The builder says that the wals weren't inspected because the walls were "in compliance with industry standards".

I have mentioned it before on this site, and I mention it to anyone who will listen - I don't believe that "industry standards" amount to much.  Each element should be designed with its own criteria, loading, and conditions.  It should not be acceptable to design a wall in Development B the same as a wall in Development A simply because the wall at Development A is "ok".  The soil likely has different properties, capacities, moisture conditions, etc.  This is true not only for retaining walls, but virtually all structures and elements within those structures.

You can bet that if this were a medical emergency, dr's would be all over every news station, and making the rounds to daytime talk shows to remind everyone how important their profession is and why only doctors can help with the problem (see all of the dr appearances when the H1N1 scare was big).

What we need is a loud voice in the (structural) engineering community doing the same for us.  That would give us greater recognition, quite possibly increase our fee structure, and certainly lead to fewer failures like this.  

The fact that news outlets are reporting the "industry standards" thing almost implies that it was accepted by an engineer, but they just didn't get a permit.  It needs to be made clear whether-or-not this wall was designed by an engineer, and if it was whether-or-not the construction was as designed (and satisfactory).

I would love nothing more than to turn on my tv tomorrow morning and see our NCSEA president discussing the issues of this failure with someone on Good Morning America.

RE: Retaining Wall Failure.

Not sure how this was constructed for sure, but a few rebars might have helped. didnt look like there was any if concrete

RE: Retaining Wall Failure.

Good view always comes with a price!

Never, but never question engineer's judgment

RE: Retaining Wall Failure.

EIT - He built it according to industry standards - the wall has weepholes. Kidding aside, I pretty much agree with you, but I wouldn't say our industry standards don't amount to much. The builder is using the "industry standard" line because he's a F-----G CROOK! I wouldn't be suprised if right now he's got his brother-in-law preparing a back-dated design & boring logs.

We have a retaining wall project that's being bid now - replacement of a 300' dry rubble wall, up to 30' high with a modular wall. The client's generic spec is based on industry standards since the contractor will select the particular wall system. HOWEVER, we did a subsurface investigation, developed design criteria, and we'll review and approve the design.

Unfortunately, many home builders (at least in northeastern Pennsylvania) are notorious for cutting corners.

As an aside: from the photos it's hard to tell what type of wall it is. It doesn't look like a modular wall or a reinforced earth type. Maybe it's a Home Depot special?

To me it looks like they might have shotcreted the slope and laid stones.  

RE: Retaining Wall Failure.

Maybe I'm not familiar enough with the term "industry standard".  To me, that means that any wall retaining a certain height can be built with xyz.  

I think that's a good starting point, but not sufficient for a final design (or to be built with).  With all the safety factors we use it likely works, but is still not a good idea.

Just imagine how under-designed a wall has to be to fail like this.  With phi factors, load factors, soil cohesion that is never accounted for, etc. it had to be woefully under-"designed".

RE: Retaining Wall Failure.

I think you might be using "Industry Standard" interchangably with "Industry Practice". Both terms can cause a lot of misunderstanding. John Q. Public has one concept; engineers have another; and lawyers - well, that's a whole 'nother story.

In a court of law, "industry standard" would generally mean:

The Design Code that an engineer would be expected to follow in a particular instance, such as AASHTO, IBC, ACI, etc. For example, you wouldn't expect someone to use AISC Steel Construction Manual to design this wall.

In the absence of a code, a court would look to see what is the accepted standard practice in the area.

An industry practice is more of a "means and methods"; for example on the east coast steel fabricators design connections; in the west the EOR does it. It's things like that.

 

RE: Retaining Wall Failure.

I am not a structural engineer.  I am a native Texan.  I have family in the construction business there.  Some of these are in the "masonry" business.  I put quotes on "masonry" because a very large amount of work done in Texas by residential level builders on stone walls, fences, fireplaces and retaining walls, is as BridgeBuster said above, "a Home Depot special".

This wall appears to be constructed without rebar, and is quite likely "engineered" by the guy on top of the scaffold yelling down, "I need a big flat one, about a foot tall, with an angled right side!  And the response being:  "Hey got just the one, lemme knock off the bump on top, I'll send it right up!

Most of my experience with this is in west Texas, but I can almost see bridgebuster's second spot-on observation going into action; a new project for "After-The-Fact-Design Incorporated.

This is going to cost somebody big bucks, and ten years down the road, if the lawyers don't get it all, maybe the homeowners might even get some relief.

RE: Retaining Wall Failure.

Next, considering the home builder, they are going to find this is a second Love Canal.

Follow the money.

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Retaining Wall Failure.

I agree with bridgebuster that these two terms are probably been used interchangeably but the implication that EIT points out unfortunately seems to be correct as well. I feel that many times it invloves how other people view engineers and engineered work. Many times the media attaches a term or presents the story in a sensationalized matter in order to get viewers or readers. The reporter may not necessarily understand the terms or the language that may be used by the engineer been interviewed. It happens in advertisement as well when the word "engineered" is attached to a product in order to sell more. I wouldn't be surprised if that "home depot special" had the word "engineered" somewhere in there as well.

When I first read the story on yahoo, if I remember correctly, the wall did not have the necessary permit. Now I wonder, how did such a wall be completely built without the permit? I believe the project was been constructed in phases so I would imagine the city inspectors had to be going in and out in the area. And the walls are not your short 3 or 4 ft tall walls, they are alot taller; so shouldn't they have across city staff at some point? At least if I was a plan checker I would have wanted to see each wall engineered for its location.

Here in the San Francisco Bay Area, the current story involves apartment buildings in danger of collapse due to erosion of the cliff fronting the ocean. In this case, mother nature is the driving force but I have been following the story in different networks, and the way that engineered aspects are reported are not necessarily in the fairest possible way to the non-engineering public. Here is a link to this story.

http://www.ktvu.com/news/22324572/detail.html

(by the way the link above is for info only, I don't mean to list KTVU as an example of bad reporting or blaming it for the bad reporting practices of others)
 

RE: Retaining Wall Failure.

Looks like they did a nice job of constructing the rock facing, but forgot to build the retaining wall first.

RE: Retaining Wall Failure.

hokie66,
I would guess that in this case whomever put up the wall couldn't tell you the difference between those two items.
EEJaime

RE: Retaining Wall Failure.

CPENG78 mentions something that I was wondering about.  How was the wall constructed without the city knowing?  If plans have to be submitted and inpsections are taking place, someone with the city should have seen this wall was greater than 4 ft.

My work does not involve residential construction, so I don't know how much inspection is actually done by city authorities.  But I have a feeling that not every house in a large development is inspected.  These developments and houses are built so rapidly that there's no possible way every one gets inspected as it should.  
 

RE: Retaining Wall Failure.

"Looks like they did a nice job of constructing the rock facing, but forgot to build the retaining wall first."

That's kind of the way things were in southeastern Queens (NYC)for many years. Contractor's did a nice job of putting in catch basins but they forgot to put in MOST of the sewer pipes.


"How was the wall constructed without the city knowing?"

If it's like NYC, there probably isn't one person repsonsible for inspecting everything. Here, the Building Department has numerous groups with a specific inspection function - electrical; plumbing; elevators; cranes; etc. Human nature -wall? not my job.

One thing though in NYC, all of the permits for a building project - and there are many - have to be conspicuously posted at the site for the general public. Builders are usually good about this in order to avoid paying fines. The city is very good about issuing violations because it makes a lot of money from fines.  

RE: Retaining Wall Failure.

I sent a letter on to one of the Professional Engineers Associations in Canada regarding a recent fatality; a CMU washroom wall collapsed and killed a youngster in their jurisdiction...

The gist of the letter was that any fatality as a result of construction should immediately open a file for investigation/review. The main purpose of professional associations is to safeguard the public.  I heard nothing...

Dik

RE: Retaining Wall Failure.

Unfortunately, as EIT points out, there's no loud voice in the engineering community.

RE: Retaining Wall Failure.

Unintentionally funny excerpt from JStephen's link:
__________
"In regards to the retaining wall, there were some reports that we previously repaired the retaining wall. Centex did fully rebuild this retaining wall in early 2007 following indications that the wall was not performing to expectations. The decision was made to completely rebuild the wall and substantially reinforce its foundation."

Get the latest crime reports in your neighborhood with the Statesman's Crime Tracker.
__________

(I don't think they actually meant to make the crime reports part of this story.)

RE: Retaining Wall Failure.

Strange how this statement does not deny that the wall was built without permit.  Further, it admits to having "fully rebuilt" this wall in 2007 including work to "substantially reinforce its foundation".  It does not say wether this rebuild was to "engineered plans" or that a "geotechnical expert" ever supervised this work, or in fact wether that re-build was permitted or ever inspected.  I think they are in a lot of trouble.

RE: Retaining Wall Failure.

Like bridgebuster mentions, that is the case for most of the cities that I have been involved here in California. They are structured so that inspections are done by different departments with different personnel. And like human nature, it sometimes ends up in been "not my job".

What human nature sometimes forgets is that directly or indirectly everyone's paycheck (whether you are the city inspector, the contractor, the engigeer or other consultant) comes from the same place; the home owner or whoever the client will be for your project. By no means do I aim to shift attention or blame away from whoever was responsible (there is such a concept as taking responsibility for your actions) for this but we call all help each other a little more if we would stop saying, "not my job". I think in the end it makes us better engineers.

CTW,
Most of my work has been in residential development. In some cases and depending on the sequence of construction such tall retaining walls would fall under either the "mass grading permit" or "grading permit" for that phase of the project.

 

RE: Retaining Wall Failure.

I was talking to a guy having issues with his house that was under construction. He had informed his builder that he wanted his CMU basement walls poured solid. The builder agreed to do it but did not. When the owner confronted the builder, he said "it's ok, I made the footing extra wide." Obviously, those two items are completely unrelated.

The problem in residential construction is the lack of knowlege about fundamentals.

Two of the most common mistakes I've seen in residential construction are 1) 10' tall retaining walls with a 2' wide footing and 2) gable walls that neither have bracing at the ceiling level or are connected adequately at the top to the roof deck.

There's nothing wrong with being ignorant. It simply mean you just don't know and need to be taught. I'm ignorant about a lot of things that aren't structural enginering.  But what you don't know CAN hurt you and a lot of home builders don't know the mechanincs of how a house distributes loads.

RE: Retaining Wall Failure.

Interesting that no mention is made of any Geotechnical report for either the subdivision or the wall.

They cite the possibility of a faulty design here.  That leaves me to assume that no Geotech report was done.  But, with the 3 foot shear key being a BIG indicator of sliding problems, I would think that there was one used. Perhaps an adjoining site?  I think I remember a comment to this effect.  

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Retaining Wall Failure.

A sheer key?  Didn't the city's engineer review the final draft?

RE: Retaining Wall Failure.

Interesting memo... he has not included information about the construction of the homes adjacent to the wall.  Did the City review this? did they have building inspectors familiar with the Code? with construction? with the permits necessary? did they observe the retaining wall? did they ask any questions about the construction of the wall? did they note the wall in any reports? any engineers on site? were the building inspectors engineers? if not, why not? from the City? If they were the only technical people involved, then the City could be in for a pile of...

Dik

RE: Retaining Wall Failure.

Who would be the owner of those retaining walls?  They appear to be between houses.  Where would the boundary be located?

RE: Retaining Wall Failure.

Let the finger pointing begin.  What a mess!  There appears to be a lot of people that failed to perform.

I often wonder what the liability ramifications are if I design something and it is not constructed in accordance with my design, but I am not engaged for the Construction Administration portion of services.  I assume that somewhere down the road, as in this memo, which states among possible causes for failure, the "Design failure in the wall was never properly designed in the first place."  [Isn't that the most atrociously written sentence?]

When this gets to court everyone ever associated with it will be named.  This memo does not state why the author feels that the design was possibly at fault, but that possibility is always on the list, especially if it is designed by a P.E. with Errors and Omissions insurance.

RE: Retaining Wall Failure.

(OP)
The wall had already failed once before, it was replaced in 2007. Granted it wasn't as dramatic a failure. That wall may have been properly built from the same plans and still failed.


 

RE: Retaining Wall Failure.

EEJaime - Legally, I think you would be in the clear on liability, but you might have to spend big $ on lawyers to prove that.   You lose either way.

The other thing about that list that bugs me is how they list "Slip failure of the soil strata below the wall" as if it would cause the problem without there having been a human failure to adequately understand and accommodate the site conditions.  The foundation is what it is.  Can't blame the dirt.

RE: Retaining Wall Failure.

dgillette,

Thank you.  "Can't blame the dirt"?  Lawyers can blame anything.  The contractor's lawyer will probably name the earthworms in his defense for undermining the wall.  And you are right, only the lawyers will make out on this one.

RE: Retaining Wall Failure.

Do not expect general clarification of the responsabilities by the legal process. They fail I think more than designers do  in their duty. They want the process finished, liabilities adjudicated, and that's all. Sometimes it doesn't matter if evidence is laid plain before them, they have their rules and they seem are quite able to disregard truth and testimony against imagined action or intent.

RE: Retaining Wall Failure.

EEjamie:  From everyone I know around here that has a problem on a project, instantly the lawyer sues each and every consultant.  The problem with this is your insurance will tell you it's cheaper to settle than to fight the issue.

That's why I make a point for mentioning what we think are issues on retaining walls if we look at another consultants plans and don't 100% agree.  I don't really care if I am doing some extra work for free, I would hate to be a homeowner with issues down the line because someone used a generic xyz design for the entire site.

That's probably why I am more curious how this wall problem ends.  Let's say I know what Centex's reputation was.  I was surprised to hear Pulte mentioned since they weren't exactly the developer at the time and I think they have a very different reputation.

Civil Development Group, LLC
Los Angeles Civil Engineering specializing in Hillside Grading
http://civildevelopmentgroup.com
http://civildevelopmentgroup.com/blog

RE: Retaining Wall Failure.

OK, maybe I should restate that as "SHOULDN'T blame the dirt." winky smile

RE: Retaining Wall Failure.

Gentlemen,

I too have been involved in contractor/client "shotgun" lawsuits which named everybody ever even remotely associated with the project and have seen all too often our attorneys' advice to "just negotiate as small a percentage of liability as possible and get on with it".  Very discouraging.  Especially when we actually had ZERO liability for the issue at hand.

We've even settled a lawsuit by one particularly unscrupulous contractor and his unbelievable incompetant and totally out of touch attorneys, whom filed suit because our enforcment of the specification on a project, insisting that they provide an item specified or an equal product was "restraint of trade".  One of the most ludicrous arguments I've ever seen.  After 4 months of depositions in which I sat and answered the same questions at least twenty times each, our attorney told us we would win at trial, but it would cost us more than the settlement they were asking.  Absolutely absurd.

The construction industry has gone to the dogs in the last 25 years, well some portions of it.  We still occasionally are involved with professional contractors and quality tradesmen and ethical ownership.  They seem fewer and farther between each year.

Regards,
EEJaime

RE: Retaining Wall Failure.

Maybe the attorneys are giving bad advice.  Maybe it would cost more to go to trial and not have to pay anything than to just settle.  That may bee true, but also short sited.  There is a reason pharmaceutical companies fight virtually every lawsuit even though it costs more to fight than to settle.  It's setting a precedent.  

Of course the attorneys will name everyone in sight if they know the other attorney is going to tell them to settle.  It's easy money for the attorneys (all of them).  

If I ever found myself in that situation, I would definitely fight it (if I were not at fault).  I think that would help draw a line about what and who should be sued.  I'm not saying my one stand would change anything, but I would certainly sleep better at night.

What is cheaper in the long run?  Settling 20 suits when you weren't wrong, or defending 3 or 4?  Isn't there some provision that would allow us to collect attorneys' fees if we are named in a suit that is "frivolous"?

RE: Retaining Wall Failure.

EIT,
I totally agree, and if I were an independant engineer in the suit I would have done as you suggest if finances allowed.  However, I was working with a mult-office, multi-state, corporate minded company that was basically run by lawyers anyway.  A no-win situation for us defending a technically 'pure' stance.  Bean counters will out.
EEJaime  

RE: Retaining Wall Failure.

When involved in litigation, you have to remember two important points.  One is that juries, being technically inexperienced, might go any way for any reason when deciding a case.  They might fall asleep during your testimony and just of had a triple Starbucks Venti Dark Roast when the plaintiffs expert is testifying.  Or they don't understand so they just split the difference. If you're being sued for $3,000,000 and you're arguing you should pay zero, they'll decide that $1,500,000 is fair to everyone.
Second, it's a small engineering world.  You might need or want to do business with the same people that are suing you some time.  Permanently pissing them off might be poor business in the future.  
I was advised by an owner of our company that it's never worth going to trial.  Even when you win, you lose.   

RE: Retaining Wall Failure.

Jed,

Is it really poor business to piss them off if they're costing you money when you're not at fault?  I know I sound like I'm on a soapbox, but some things just really aren't right!

RE: Retaining Wall Failure.

I'm not particulary fond of attorneys either. We got hit with two crazy lawsuits back in the 90's. The first was a bridge rehab project. Out involvement ended with final plans - RFI's, construction support, shop drawings - the things the designer would normally handle were done by the firm hired for the construction inspection. Here's what happened: The contractor installed a section of SIP forms at the wrong elevation. He sends to ironworkers to remove the forms. They were standing on the forms as they were cutting them. The men fell about 40 feet. Tragically, one was killed; the other permanently disabled.

We were sued along with the contractor. Why? Our name was on the plans, even though the attorneys knew we weren't involved. Then again, if lawyer-logic there was the remote possibility that it was our fault the forms were set wrong. Initially, the lawsuit didn't include the CI firm. Anyway, we were eventually released from the suit but it cost us $75 grand - insurance deductible. It was a lot of money for us - we were a small firm at the time.

In the second case, we prepared plans for a bridge deck rehab - new overlay. The bridge has three lanes in each direction (east and west). In the mornings, the left lane of the east bound side is used as a bus lane. There's an opening in the concrete median and PLENTY of signs that say "BUSES and TAXIS ONLY". The bus lane is delineated with cones every 10'. One morning, a motorist went in the bus lane, then he went into the center lane - head-on collision; killed instantly. Again, our name was on the plans. I don't recall how much it cost us to get out of the suit.   
  

RE: Retaining Wall Failure.

Second, it's a small engineering world.  You might need or want to do business with the same people that are suing you some time.  Permanently pissing them off might be poor business in the future.  

I know times are tough but that's ridiculous.  It would only be poor business if you chose to do business with someone who previously sued you.   

RE: Retaining Wall Failure.

Lawyers are in the same boat... if they miss someone that could have been included on their list, they, in turn, can be sued!

Dik

RE: Retaining Wall Failure.

Engineering firms get sued by large clients for any number reasons.  Politics, incompetence, revenge, jealousy or just plain orneriness.  If you take it all personal, it will affect your business.  No one is going to look good in a trial, even if you're right.
You don't have to believe me, but you're going to run into the same people after the litigation is over.  You can settle or fight to the death.  Is that where you want to spend your energy?

RE: Retaining Wall Failure.

As they said in the Godfather - "it's not personal; it's just business."

Of course, it's a lousy way to do business.

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