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Geotechnical Report, subsurface exploration, and lab work

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ATSE

Structural
May 14, 2009
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For a mid-size structure, are there published national standards for geotechnical engineering report content, along with subsurface exploration minimums and lab work minimums? Minimum subjects to address in report, number of borings or soundings, max boring spacing & depths, short list of ASTM tests (two ASTM D4318, three D2216, one D2844...).
Say, for a single story 40ft x 60ft masonry bldg with a steel roof. Moderate to high seismic. Some paving, some underground piping.

I am not looking for common sense or rules of thumb or general concepts - I have a dozen of these already.
Currently I use:
1. FHWA ED-88-053 (can't find an update to this oldie but goodie)
2. FHWA NHI-01-031 - Tables 2.2, 2.3
3. CGS Note 48 - for geohazards only, not a general resource
4. NAVFAC Vol I, Tables 6, 7.

FHWA documents are always useful, but of course usually not for buildings.
Most of my work is heavy civil municipal, where the buildings are a minor part of the scope. But sometimes there is just a masonry bldg with mechanical equipment and tanks, so the project managers think they can go to Walmart and pick up a geotech report for half price.
The geo work scope shows a couple of borings to 10ft and some lab testing. Better than nothing, but it gives me heartburn. Then we argue about risk and standard of care. For these small to mid-size projects, the firm usually spends less than 1% on the entire geotechnical scope.
Seems like a professional society like ASCE or industry/insurance association like ASFE (now GBA) would have something for non-transportation, non-military building work - I just can't find it.
 
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I'd recommend contacting the local geotech firms that do both the field investigations, any testing and write the report always under the supervision of a PE. From the more experienced firms I'd then modify that guideline to suit the jobs you may have. Of course asking them "what would you recommend?" might also be useful on short notice. In my experience the structural engineers I have worked with leave it wide open for me to decide what should be done recognizing that I also then take on some responsibility that they do not have to be concerned with. If you have to bid the work it still would be best to have at least one experienced geotech review your proposal for a specific job. In he rare instance where the structural engineer does about what you describe as to details for the field work, I (and firms I have been with) hesitate to have anything to do with it. You stand to have some claims down that road.
 
No national standard that I can think of. The study scope for a small to mid-sized building would be totally different from southern Louisiana to north Texas to California. Structural engineers often try to shoe-horn geotechnical engineering into a code book the way structural engineering is. I understand the intent and that you are just trying to have some apples to apples comparisons, but you just cant' have that - sorry. OG's advice is sound.


 
There is an organization that provides exactly what you are looking for. It was once known as the Association of Soil and Foundation Engineers (ASFE), but is now known as the Geoprofessional Business Association. They have some excellent publications for practicing geotechs.

Geoprofessionals
 
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