| Author |
Message |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 983
Registered: 05-2003
| | Posted on Wednesday, June 12, 2013 - 01:45 am: |    |
I'm curious, I have a project where the Structural PE has refused to prepare the section (its odd because in 2006 we worked on a similar size project for the same architect in the same approx. location, and the Structural PE did prepare Section 02370, in my opinion a very good section, unfortunately that project was never built. So now the Geotech Engineer has been retained to provide one that I am just not happy with - too much Geotech BS, not enough structural engineering. Has something happened over the years that I don't know about, regarding foundation specs prepared by engineers; I have several other projects where piling specs by Engineers just don't feel right. |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 571
Registered: 10-2007
| | Posted on Wednesday, June 12, 2013 - 02:52 am: | |
There are two things at play here. First some engineers are not comfortable writing specifications and would prefer to rely only on general notes. Second is the fact that the specifications for some foundation systems include a lot of geotechnical issues which the structural engineer does not see as in his scope of work.
You are lucky in that your geotechnical engineer is willing to write the specification system. It is changing but I have seen some geotechnical engineers who have said that their involvement with working drawings is limited to review of construction documents prepared by others. This can create problems when the structural engineer rightly refuses to author the earthwork specification section.
You mentioned that there was too much geotechnical and not enough structural content. I am sure that the geotechnical engineer would have the opposite reaction if the section was authored by the structural engineer. When an architect tries to write a rough carpentry specification section I have similar concerns.
In any case these foundation specification sections require the active involvement of both the geotechnical and the structural engineer. Who should take the lead for some of these systems is open for negotiation. I have written an auger cast grout piles spec section but the proper installation is driven by geotechnical issues. Still the engineer who designed the pile should make sure that the materials are properly specified. |
Jerome J. Lazar, RA, CCS, CSI, SCIP
Senior Member
Username: lazarcitec
Post Number: 985
Registered: 05-2003
| | Posted on Wednesday, June 12, 2013 - 03:22 am: | |
Thanks Mark I was hoping you would respond. One of the problems with the Geotech's spec section is that it reads 50% like a Geotech Report, with data that does not belong in a spec section and 50% like a spec section. The format needs some work and his Quality Assurance verbage is sub par. I doubt the author belongs to CSI and this may be his first time writing specs.
BTW, the Structural Engineer of Record for the project has prepared full CSI specs for CIP Conc, Post Tensioned Concrete, CMU, and Structural Steel, very well prepared, just not Auger Pressure Grouted Piles....weird? |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 572
Registered: 10-2007
| | Posted on Wednesday, June 12, 2013 - 01:55 pm: | |
Geotechnical engineers are even less likely than structural engineers to have had specification writing training let along belong to CSI. CSI has too long been insular in that it has focused on architects and their specifications.
To improve the specification section you need to find a mechanism to provide feedback. Assuming that the Geotech is willing he most likely does not understand where you are coming from. He will need some handholding. You might share with the Geotech the auger pressure grouted plié specification section to give him an idea.
Explain why you are concerned that that the section looks like a Geotechnical Report. Point out that the Geotechnical report, which will be made available to the contractor, provides background information but the specifications is where you tell the contractor what is expected of him.
Consider getting the structural engineer and the geotechnical engineer together for a working session since they both own parts of the section. You often walk a fine line between offering suggestions and being accused of directing the content of the specification section.
The structural engineer’s reluctance is probably related to the fact that this is a system that is more driven by geotechnical issues and less by calculation of structural capacities. I would expect to see some load testing of piles to verify capacity. |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 664
Registered: 11-2004
| | Posted on Wednesday, June 12, 2013 - 07:19 pm: | |
It's been a while since I have been involved, but isn't this system semi-proprietary, in the sense that only a few companies can do it? If so, then wouldn't this be a candidate for a delegated design by the contractor (or sub-contractor)?
In that case, the structural engineer and geotech would produce performance criteria and testing requirements, and the contractor would provide the final design, including detailed specifications if required. That was my experience on specialized foundation systems such as this.
George A. Everding AIA CSI CCS CCCA
Ingersoll Rand Security Technologies
St. Louis, MO |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 585
Registered: 10-2003
| | Posted on Wednesday, June 12, 2013 - 07:32 pm: | |
When I've had them on a project, the Geotech didn't do them and I had to "twist the Structural Engineer's arm" to get him to review what I had put together.
It's my position that since the Geotech is generally hired by the Owner, it should be the responsibility of the Engineer of Record to produce, or at least review, the section. After all, it's his foundation that is going on top of the piles.
On larger projects that I worked on, we generally had a foundation engineer consultant that took care of it. On smaller projects, I always ran into the same problem of neither party wanting to take responsibility. |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 573
Registered: 10-2007
| | Posted on Wednesday, June 12, 2013 - 07:36 pm: | |
While this requires a specialty contractor there is nothing proprietary regarding the work. In addition most of the contractors are not set up to provide engineering. |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 575
Registered: 05-2004
| | Posted on Thursday, June 13, 2013 - 07:44 am: | |
At some point somebody has to be responsible for something, and I suspect that it should be the structural engineer. Somebody has to determine how much load will be carried on each pile, someone has to determine the load capacity of the soils on site, and someone has to determine how the load will be transferred. My vote is for the structural engineer. If they want to try and transfer some of the liability to the contractor, they will still have to develop some performance criteria.
As for the contractor's not being set up to do engineering, they can hire an outside consultant. They should include this in their bid. Someone has to be compensated for taking on the liability.
It is frustrating to have consultants contracted for services exclude certain design components from their work. |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 574
Registered: 10-2007
| | Posted on Thursday, June 13, 2013 - 12:58 pm: | |
First let it be noted that I probably would author an auger cast grout pile specification section but I would definitely make sure that the geotechnical engineer bought into the specification section because much of the section is in the geotechnical engineer’s work scope.
In some of these foundations systems there is not always a clear dividing line of who should naturally prepare the specification section. The structural engineer definitely does NOT determine the load capacity of the soils on site nor how the load is transferred from the pile to the soil. Using the logic put forward the structural engineer then should be responsible for the geotechnical engineer’s recommendations. Think again.
Note that our structural codes do not well address how to calculate structural capacities for auger cast grout piles. In some sense this system is justified as much by load tests, which are typically specified by the geotechnical engineer.
The structural engineer gets a vote in this decision. This points out that even in the best contract for professional services there are areas of ambiguity that will need to be worked out. The architect should share some responsibility for the ambiguity since they negotiated the contract with the structural consultant.
Often times it will not be clear what foundation systems will be considered at the time the structural consultant is hired. These choices can have a significant impact on the engineers work. Most fee structures do not allow one to build in contingencies for all possible foundation systems.
You hit a sore spot because too often the structural engineer is supposed to absorb scope of work because something has a structural component to it. The reality is that there are structural issues related to most aspects of a building. In many instances these issues are not formally addressed because nobody is willing to compensate the engineer and because the architect or others do not want the engineer involved in something that they think they know how to deal with even if they do not.
I have long been of the opinion that geotechnical engineers have for too long been passive in the development of construction documents. I could easily make the case that the geotechnical engineer should design many foundation and retaining wall systems. As always the interface must be managed but that is not a new problem.
While the contractor can hire an engineer many of these contractors are not sophisticated enough to manage consultants, may be inclined to hire a cheap consultant, and their consultant will (in my experience) probably not create a specification section. Delegating the design of the foundation systems may not be feasible if the Owner insists on bidding the work and the building official requires a complete foundation design at the time a building permit is issued.
If a compromise could not have been worked out an option would have been for the Owner to hire a specialty consultant to design this system. Note that a decision to delegate the design to the contractor would result in the Owner paying more to the contractor and would give the owner less control over the foundation design. So the decision to delegate the design only helps to hide the problem. |
Tony Wolf, AIA, CCS, LEED-AP
Senior Member
Username: tony_wolf
Post Number: 54
Registered: 11-2007
| | Posted on Thursday, June 13, 2013 - 02:26 pm: | |
There are a number of sections that disciplines do not want to take on, even if they have traditionally. Since there's no standard available to reference, this seems like a perfect task for CSI, to help the specifiers and the industry by identifying these points of connection/contention and providing guidance to help resolve. |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 575
Registered: 10-2007
| | Posted on Thursday, June 13, 2013 - 02:57 pm: | |
Agree the first step is to recognize the issues and then to develop strategies. The various disciplines need to be part of the discussion.
The solutions cannot be imposed from on high. |
Ron Beard CCS
Senior Member
Username: rm_beard_ccs
Post Number: 405
Registered: 10-2002
| | Posted on Friday, June 14, 2013 - 05:38 pm: | |
Another structural engineer-geotech issue that continually comes up are references in Structural Notes to the soils report as if it where a Contract Document. {This topic might be another thread.} Recent example: Note on Structural Dwgs in reference to subbase under a slab-on-grade: "See geotech report."
I assume that most of us still adhere to the fact that a soil report is not a contract document but, rather, recommendations to the project's design team. At least, I still adhere to this policy and so state in my project manuals.
As a general rule, I have always prepared an initial draft of structural sections for the SE's review and sign-off. This has, for me, provided the best interface between structural and other sections-desciplines. Unknown subsurface conditions is always a potential issue for projects. If the project is designed with certain design intents (depths, types of soils-stratas, bearing capacities, etc.) which are found not to be the case, change orders are my preferred choice. This way the base bids are apples-to-apples. If change orders are not options (as is the case for some owners), units prices or contingency allowances are available.
"Fast is good, but accurate is better."
.............Wyatt Earp |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 576
Registered: 10-2007
| | Posted on Friday, June 14, 2013 - 07:19 pm: | |
Totally agree that geotechnical reports should not be referenced to indicate compliance. The Geotechnical report should be provided to the contractor to inform him of what the Owner knew about regarding soil conditions. Structural Engineers should be directed to correct this practice.
When Architects provide structural consultants with initial drafts of structural sections this just encourages the structural engineer to take a passive attitude towards specifications. Consultants will feel that they are being directed to use the Architect's master and thus will make fewer changes than they would otherwise.
This may make your life easier in the short term but can have a negative impact on the quality of specifications. If there is litigation I can envision a consultant suggesting that he was directed to use the specification language and thus the Architect should share the liability.
As stated previously architect's master specifications are often outdated and reflect an architectural bias that is inappropriate for a structural specification section. |
Ronald L. Geren, AIA, CSI, CCS, CCCA, SCIP
Senior Member
Username: specman
Post Number: 1121
Registered: 03-2003
| | Posted on Saturday, June 15, 2013 - 03:39 pm: | |
An article I wrote about three years ago on the subject of geotechnical reports and contract documents:
http://www.specsandcodes.com/Articles/Keynotes%20No.%204%20-%20Geotechnical%20Reports%20-%20Contract%20Documents%20or%20Not.pdf
Ron Geren, AIA, CSI, CCS, CCCA, SCIP
www.specsandcodes.com |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 577
Registered: 10-2007
| | Posted on Saturday, June 15, 2013 - 09:28 pm: | |
To address this problem I would propose a three stage process.
First work with your consultants to agree where and how the recommendations of the geotechnical report will be addressed in the construction documents.
Second let any consultants who insist on requiring compliance with the geotechnical report know that if there is any claim related to such statements that the Owner and other consultants will look to the offending consultant to pay all costs.
Third let the offending consultant know that if they continue to follow such practices they will not be hired for future projects. |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 576
Registered: 05-2004
| | Posted on Sunday, June 16, 2013 - 08:27 am: | |
In our area, the problem that I frequently see is not concealed conditions, but varying conditions. The clayey-silty-sandy "gumbo" is expansive, but is usually dealt with by stabilization although it is not unusual for several feet of unsuitable soil to be removed and replaced with materials that are satisfactory. During rainy periods, this can be difficult if not impossible to deal with existing conditions, and the schedule will be delayed until soil conditions are dry enough to work.. This affects not only building slabs on grade, but paving as well. For a car dealership, I worked on, the site was almost completely covered with building or paving. A combination of existing soil, rain, and flat terrain would mean that the wet gumbo would "pump" when earth moving equipment was operated on the site. The problem was nonexistent during dry periods. The geotechnical report will reflect site conditions at the time the onsite investigation is performed. Recommendations for soil stabilization may be made "for the purposes of bidding only.". The Owner's geotechnical consultant will usually be retained to verify site conditions and make recommendation to the contractor that reflect the current conditions that can vary significantly from those in the geotechnical report. Subsurface conditions are usually not affected.
The biggest problem that I have heard of is with Ôwners from other parts of the country who are not used to dealing with such unstable soil conditions. |
Mark Gilligan SE,
Senior Member
Username: mark_gilligan
Post Number: 578
Registered: 10-2007
| | Posted on Sunday, June 16, 2013 - 01:22 pm: | |
It would appear that the varying site conditions mentioned are well known and thus could/should be mentioned in the geotechnical report. Thus it should be possible to shift the risk to the contractor.
Since the problem is apparently well understood I would expect the grading specifications to address the varying conditions that commonly occur.
While the geotechnical engineer gives recommendations to the owner and his consultants the Construction documents give direction to the contractor. Thus when the owner's geotechnical engineer gives "recommendations to the contractor" I would assume that the contractor can rely on these recommendations. |
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