Geotech relationship to building project 2

[JAE]

There has been some discussion of this topic in the past, but a recent project investigation has prompted me to post this to see what others think.

Scenario:
A typical, small building (about 6000 sf) one story, wood framed with brick veneer on concrete spread footings.

An A/E firm hires the geotech via the owner and gets a typical geotechnical report, outlining the soil conditions, bearing pressures, stuff about pavements, etc. Nothing real extraordinary except that the geotech warns about a couple of things:
a) Might be some concerns over the bearing soils - and gives certain recommendations about dealing with those concerns.
b) Says that they (the geotech) should review the plans for conformance with their recommendations.
c) Says that they should be hired to do on-site consulting to verify if the soils are ok, that construction practices are proper, to do testing of compaction, etc.
d) Says that if they aren't hired, then they cannot be held responsible for any problems.

OK - this is all fine - and I don't see anything wrong with it so far.

So the A/E firm uses the report, designs the building, issues it for bid, and it gets built. But the geotech was not given an opportunity to review the plans.

Instead, the contractor is instructed in the specifications to hire a testing lab to "perform tests and inspections" but other than compaction tests, no specific mention is made about reviewing the soil conditions, etc....just compaction tests.

The building ultimately has some severe foundation problems and some of them are possibly due to A/E details not conforming with the original geotech recommendations.

So my basic question is this:

Most construction documents contain drawings and specifications that almost always focus on the requirments of the contractor.

It seems that in this case, and probably in most typical US construction cases, the contract documents don't deal at all with the issue of the geotech reviewing the DESIGN. How many A/E firms do you see giving out their designs back to the geotechnical engineer for review of the design? It seems that it is a common loophole that disallows a good check and quality assurance method....

In this case, the A/E didn't insist on the review, did not follow a certain procedure recommended, and bad things resulted, at least partially from the disconnect between the design and the report.

Also, have you ever seen in any contract documents requirements for the contractor to ask their testing lab to review the design for any problems related to the geotech report that the testing lab may or may not have written?

Thanks for your patience in this long post - and thanks in advance for your replies.

 

[MRM]

JAE,
You've hit on one of the big problems with doing geotech reports in general. Although A/E firms are among the best possible clients a geotech could have to work with, many of them still regard geotech services as a CYA measure only; a necessary evil, a checklist item, an insurance policy, if you will. The last thing they want to do is cut into their profits, or bother their clients further with additional soils work during design or site excavation.

To answer your first question, very rarely do we become involved in the project to review plans prior to bid or construction, which can be dangerous to all parties involved.

They take the geotech report, perhaps scan it over, then file it away. I try to always follow up the report with direct phone contact within a couple weeks. I reinterate the importance of plan review and site observation during construction. Nine times out of ten they tell me don't worry about it and they'll call me if or when they need us. My first defense at that point is to document the phone conversation with exact time, date, and actual dialouge.

One other problem I see a lot of is this; our A/E client will call us during site work. They'll want some density tests on the subgrade and backfill. I'll offer to have us check the plans further, along with a more comprehensive subgrade check using more than just a muke guage. They usually tell us to simply get some density tests make sure they're 95%, leave the site, and send them a density test report. My second line of defense at that point is to note on that report that density results were obtained at the subgrade level or the top of the backfill only per clients directions. No allowable bearing pressures were determined based on this testing. The underlying fill soil compaction was not observed or tested.

I can't think of anything else we could do. Always open for suggestions!

 

[BigH]

MRM - on your point to document. Suggestion - make sure you send the documented conversation to the client for his records. ASFE - the soils association - has many good publications (I understand) on such issues and if you are a member firm, you can check them out. If not, you should consider it. I work for a very very large firm and the geotech is so small - they wouldn't; but for a specialized firm - consider it. This is always the bain of geotechnical engineering - that is, being able to ensure that your recommendations are followed. One of the reasons to have good disclaimer clauses at the rear of your report.

 

[MRM]

BigH,
That's a great reminder about sending a hard copy to our client reminding them of our conversation. I sometimes do that when there are very special foundation concerns on the site, but I should be doing it routinely-even for the sites that have "forgiving" soils.

Your disclaimer comment is certainly important. In addition to being a very cogent point, it also reminded me of a conversation I had last summer with a much more seasoned geotech engineer than I. In fact, I think he's been trying to retire for about 8 years now. We were talking about a particular site and he remarked that more than half of our report appeared to be CYA measures... I agreed that it indeed was! I’ve studied old reports and compared them to the reports we put out now. I'm not sure what happened over the years to society to require so much extra in the way of disclaimer language in a report, but I'm willing to bet that those measures have added significantly to the overall cost of an otherwise simple geotech report. I'm talking about the cost of extra writing time, whatever extra professional liability insurance is required nowadays, and lastly, the extra cost of paper and ink! But what can you do, it's required now. That kind of leads me to ASFE...

Our company has been a member of ASFE for quite a while. I've tried to soak up as much info as I can from ASFE. I'd have to say that of my (and my company's) professional affiliations, ASFE has been one of the most valuable. Actually JAE, ASFE started out, in part as I understand, to deal with the problem that you described in your post.

 

[VAD]

I think MRM and BIG H have covered the topic adequately. here is my few cents or dollar.

Cut into their profits is likely Number 1 since many do not let the client know the scope of the geotehnical assignment or some get the job first then worry about the geotech after. They do some shopping around for prices and get some geotech who will go cheap. Ask the drillers they know how it is done. Generally, depending on the nature of the project all may go well.

Whether the Client has to pay extra for construction is generally not a problem. Clients have no problem doing that as they see it as getting the finished product. Geotech issues are generally buried beneath the ground until a problem manifests with a structure then of course it is the geotech's fault. The problem generally is with the cut throat nature of the business of consulting engineering.

I have been able to review plans prior to construction in many instances but it depends on whom you work for and how you articulate your report. Many times you may have to keep the Client wondering while still providing him with a recommendation. Provide him with recommendations that are preliminary and let him know when he has developed his concept then you will refine yours to every one's advantage. Let him know of your concerns if there are ones which you feel would impact design and construction.

Tell him upfront, verbally and in writing, at the time of assignment that you expect to see the plans and tender documents for the project before construction so that you can confirm that they have incorporated your recommendations appropriately. Depending on the nature of the project, you may wish to have interim reviews as well.

Let the Client know that unless these conditions can be met you will not be responsible for any problems that may occur.

Very often Clients do not necessarily contract with the same firm who did the geotechnical design during construction if the project is done in two stages - design, then construction sometime after. Sometimes this leads to issues missed during design being observed. On the other hand there may be disagrement about recommendations. The problem very often is that geotech reports do not often provide how values are obtained until a dispute arises. Even among ourselves, we have differring opinions on analysis, design etc.

Despite the above there are projects - 0ne or two boreholes dictated - in which the A/E firms price shop - Where can I buy burgers today for 99 cents etc. You really do not want those projects as often they are the ones that give the most headache but in the eyes of the A/E there is no real problem and the job is simple. On the other hand many make a comfortable living doing those as they get a large number of them.

I am not sure that there are any better answers except that you have to use a lot of persuasion and at times also to say - take a hike. You may loose Clientelle by doing that but at times such decisions are appropriate.

Do you not get the feeling also that some geotechs may be happy that they are not called to review the plans or to make site reviews but look forward to just do the densities.

My recommendation is to assess the project you are to be involved with and decide whether you carry the hammer from the inception. It may be advantageous to outline what the scope of work should be for the project and give it to your Client. Let him tell you the ones that he does not want.


Regards

 

[DRC1]

I agree this is a problem. I used to work as a geotech for a consultant but now I am in heavy construction. Geotech involvement in a project is far too slim and investigations and sampling are not adequate.I once told a consultant that an owner can not spend too much money on design. For every dollar spent solving a problem in the design office before the bid, the owner saves 10 dollars if the problem were found after award, $100 after construction has begun and $1000 or more after construction is complete. These were based on actual changes. The multipliers will vary, but that is the order of magnitude. I disagree with VAD on one point. Owners are not generally willing to pay for unanticipated changes, especially when the final product does not change. The contractor usually recieves the first shot.Thats why I wouuld answer JAE last question as the contractor's testing lab only tests to the requirements it has been given in the contract.
One problem I see coming from geotechs is the cookie cutter approach to reports and solutions. Often times if I read a page of a report that is included in a bid package, I can usually tell what firm wrote it. I hate to say it, but a lot of you guys don't inspire a lot of confidence in original thinking if every report looks the same. Also the methods and specs look the same from job to job. I know guys who always drive precast piles or always drive pipe, then always use the same driving limits, etc.no matter what the site is like. Why would an A/E be inclined to engage a firm for further study if the A/E could have written the same report himself by taking the last report and changing titles and site location? I'm not trying to be hard, but it is the other side of the coin that raerly gets any dicussion.

 

[BigH]

DRC1 - good points. It is good to have the input of the "contractor". As for original thinking - there is a point here but - here's a bit of story;
Back in 1964, when eminent geotechnical engineers (and I could name at least one Terzaghi lecturer) were in their early careers, there was a project on the Ontario Peel Till Plain - a clayey till with N values >25 for the most part. Site was flat, a single storey warehouse was the project. No site hiccups; straight forward. The geotechnical fees was $3000 Canadian (1964). Drilling was only about $25/hr. The eminent geotechnical engineer had approximately 60 hours of involvement in the project to look at the field samples after arriving at the office, design and prepare the report.
Back in 1995 - same location (or damn close), the geotechnical engineer had to take the job for $1450 Canadian (1995). He had to pay his drilling (at $110/hr)and site supervision out of this. In the end, he had only 6 hours of involvement with the project - to maintain his budget (a few free hours tossed in).
Is there any wonder many geotechnical reports seem to be boiler-plate without much original enlightenment?
HHHmmmmmmmmmm.

 

[GeoPaveTraffic]

The points made above are very good, and there is little that I could add.

One thing that the City where I currently work, and many others in the area, require is that the Geotech sign and seal the grading plan along with the Civil. That at least makes sure that the grading plan is in accordance with the Geotechs recommendations.

Otherwise, I believe that nothing will change until geotechs stop competing with each other on price; and I don't see that happening anytime soon. The current state of the profession is one of the reasons that I left geotechnical consulting and went into project management for heavy construction for the City.

 

[dmoler]

Dont mean to do a "what I really hate is..." , but what I really hate is the client who sends the plans and asks the geotech to review to see if they follow the recommendations, and the client expects this for free. (They really expect that for free, especially for the subdivision work). (groan)

 

[connect2]

JAE,
First off i've never seen any consultants hand off thier responsibility for review to the 'contractor' so there you go on that one...
secondly any time we design foundations we make sure the dirt guys get a look at our design BEFORE its tendered. We have a particular clay here that is very problematic, and settlement questions are paramount, so we'll hold up the design portion of the job until these questions are answered to our satisfaction .... which is always a $$$$ type problem and solution in the end.
thirdly we always require the involvement of the dirt guy in the on site review during construction .... period .... it just makes sense, although we've lost a few clients that way, but thats fine, we've always found a few more.
I know a couple of good geotech guys here, there a pleasure to work with.

 

[GAFenton]

Valuable comment, JAE. Clearly this is an area of significant concern to the geotechnical community, judging by the range of insightful comments above.

Along these lines, one of my favourite quotes is "You pay for a site investigation whether you have one or not" (Institution of Civil Engineers, UK, 1991).

Also, Jaksa (2005) says "Many studies over the last 15 years or so have clearly demonstrated that, in civil engineering and building projects, the largest element of financial and technical risk often lies in the ground".

In my opinion, the reason Jaksa's statement is correct is because geotechnical engineers "often" do not have control over the risk associated with their domain.

Structural engineers assumed control over their design risk many years ago. How did they do that? I think that the answer lies in the building codes.

Geotechnical engineers need something in the building/geotechnical codes that allows them to control their risks (and costs!) -- the only way that will happen is if they work together and lobby for it. One way to start is as suggested by BigH. We should also push for a "Thou shalt" clause in the appropriate design codes.

Let's do whatever the structural engineers did 20 years ago.
Just because every site is different doesn't mean that geotechnical engineers can't work together (I hope).

Perhaps it's time that the A/E's become A/E/G's?

1) Institution of Civil Engineers, "Inadequate site investigation", Thomas Telford Pub, London, 1991.
2) Jaksa, M.B. et al., Towards reliable and effective site investigations, Geotechnique, 55(2), 109-121, 2005.