Screw Pier Variation 1

[OzStruct]

Hi All

I have recently designed a project which utilized many screw piers. The project manager got a few quotes to do the piers and we sent the winning pier company out to site before signing the quote to do some test piers, which they did. They designed the piers to hopefully found at 5m depth. First day on site they say the piers are not pulling up at 5m depth and we need to splice the piers and extend them to found at 8m were we are getting the required pile capacity (around 100kN to 150kN). Then after they have installed all the screw piers they turn around and hit my client with a huge cost variation, which he is not very happy about and does not want to pay.

We sent them out to do a test pier so I think they should have known about the soils conditions. We also had a very good geotech report which they have. I know this is more of a project management question but I am curious to know your thoughts. How do we know that the piers didn't pull up correctly at 5m and that the splicing of piers is just an excuse to go for a variation? Also is the client just at the mercy of the pier contractor for the amount of the variation they can claim? Seems very unfair to the client as we all went to great lengths to avoid this happening.

Thanks

 

[BAretired]

I believe you and your client have a pretty good case. A disparity of 3m in depth is unacceptable in view of the fact that they were given a soil report and permitted to do their own testing.

BA

 

[oldestguy]

Why didn't you have an inspector on site? If not, you don't have much to stand on. However, I surely hope you required a log of torque required versus depth for each pile.

 

[Once20036]

How big is the site?
How many borings were done as part of the geotech investigation?
How many tests did the contractor perform?
Where were the 8m piles in relationship to the contractor tests or geotech borings?

Ultimately I think this is a contractual question, but if you have a large site with limited testing, the contactor couldn't possible do enough trials to be responsible for variations across the site.

 

[OzStruct]

Thanks for all the feedback so far, much appreciated.

4 bore holes were done in the building foot print and the material is consistent throughout. Basically stiff clay to bore hole depth termination. I think the pier company did 2 test piers before fabricating the piers and going to site. All of the piers needed splicing extensions of 3m.

 

[sekwahrovert]

I agree with Once20036. This is a contractual question.

 

[dhengr]

OzStruct:
Again, I agree with BA, but a ‘60% overage’ would probably sound stronger in court. I also agree with Oldestguy’s statements, except I think you have a better case, in court, than he does.

The phrase “to hopefully found at....” should not appear anyplace in their quote or in the contract language. That is incredibly bad phrasing for your cause, maybe just a slip-up here on E-Tips. This sounds like a perfect example of the worst communication and construction planing in the world. Almost guaranteed to lead to a fight later. I would want to have seen their torque/depth logs for their test piers also, where there enough piers to be meaningful, and I would want to have seen the test locations on the job site too. It sounds like they said (“designed the piers”??) 5m long because that was what their bid was based on. And, if they came back and said ‘o.k., we’re ready to go,’ without telling you their final invoice was going to be 50-70% higher than their bid, they should have to live with their original bid and supposed testing and study of the soils report. Of course, in hindsight, you might have asked, after the their testing... ‘and your bid is still o.k.?, then go ahead.’ This would have put you in an even better position now. It’s the old, trust, but verify situation. You can’t always trust in the first part and you should always do the latter part.

 

[thaidavid40]

A quick question. If they had returned to you after testing and said that they would have to go to 8 meters, and the cost would go higher, would you still have done the project? If not, then you have a great beef with the contractor. If you still would have done it anyway, then it seems you really have no rational basis on which to dispute this. The job required what it did to reach the results desired. And that costs what it will cost. Did you want the job done to specs, or not?
Just food for balancing, rational thought,
Dave

Thaidavid

 

[BAretired]

The "huge cost variation" should have been presented to the owner before the screw piles were all installed. Perhaps another foundation scheme could have been found at a more equitable cost. The pile contractor acted inappropriately in completing the work without authorization from the owner or his representative.

BA

 

[EngineeringEric]

If deny paying the extra amount will they just back the piers up 3m and leave you with 5m embed?

Look at the torque logs of the piers, compare that to the tests and the results of the boring analysis... there is a problem somewhere but this is not an engineering problem.

 

[oldestguy]

I trust you have complete written records of every phone call, emails, as well as written correspondence. This case may take years to resolve and memories are not good as time goes on. Your professional liability insurance carrier should have been informed early on. If not, do so now. Heed the advice of your attorney. Communications with the contractor may have to be restricted also.

 

[kipfoot]

I'm stating the obvious, I think, but I would expect that their initial bid would have included a unit cost for linear feet meters of pier beyond the initial estimate of 5m. (this could also go in the owner's favor if you find rock at 3m in some cases)

From the contractor's perspective, they may have believed that when they told you they were going deeper that the client would understand that there would be cost implications, presumably as outlined in their agreement.

Without a prior agreement on what the additional unit cost would be it becomes the subject of negotiation. The final unit cost may end up somewhere between the contractor's first number (their bill) and the owner's intention (zero). Hopefully you all can find that number without the help of dozens of lawyers.

And like oldestguy suggests, I'd say to give your liability carrier a heads up.