No Geotech Report
No Geotech Report
(OP)
I have two questions:
1. What would be a good value to assume for the shear modulus of a sandy clay?
2. Would you ever design a foundation without a geotech report?
Thanks in advance for your help.
1. What would be a good value to assume for the shear modulus of a sandy clay?
2. Would you ever design a foundation without a geotech report?
Thanks in advance for your help.






RE: No Geotech Report
2. IBC (if that is what you use) permits you to assume values without a report. I have done it but don't like it and think it is bizarre we have to jump through so many hoops for other calculations then it allows you to just assume a soil bearing capacity for a site.
RE: No Geotech Report
RE: No Geotech Report
RE: No Geotech Report
You USE the value in your design, so in your notes, state it as the DESIGN value based on Table XXXX in the IBC for example. Although not always possible, a personal visit to the site helps too...
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: No Geotech Report
BA
RE: No Geotech Report
Explain to the owner he can either pay for the $2K-$5K report now or pay for it in construction since you will be putting it on your drawing that the contractor must confirm it before construction. The downside in waiting is that you may also incur charges for redesigning foundations if the existing conditions do not meet your assumptions.
PE, SE
Eastern United States
"If a builder builds a house for someone, and does not construct it properly, and the house which he built falls in and kills its owner, then that builder shall be put to death!"
~Code of Hammurabi
RE: No Geotech Report
RE: No Geotech Report
RE: No Geotech Report
RE: No Geotech Report
RE: No Geotech Report
GEOTECHNICAL
A GEOTECHNICAL REPORT HAS NOT BEEN PREPARED FOR THIS SITE. THE CONTRACTOR, THROUGH THE CLIENT IS RESPONSIBLE FOR OBTAINING A GEOTECHNICAL REPORT TO CONFIRM DESIGN ASSUMPTIONS. THE [CONSULTANT | ENGINEER] ASSUMES NO LIABILITY FOR THESE DESIGN ASSUMPTIONS OR FOR ANY FOUNDATION REDESIGN NECESSITATED BY DIFFERING SOIL CONDITIONS
FOUNDATION DESIGN IS IN ACCORDANCE WITH THE GEOTECHNICAL REPORT PREPARED BY XXX, HAVING A FILE No.xxx AND DATED XXX. THE CONTRACTOR SHALL REFER TO THE INFORMATION CONTAINED IN THIS GEOTECHNICAL REPORT AND SUPPLEMENT IT AS REQUIRED. THE CONTRACTOR SHALL REVIEW THE GEOTECHNICAL REPORT AND FOLLOW THE RECOMMENDATIONS WITHIN THE REPORT PRIOR TO PROCEEDING WITH ANY FOUNDATION WORK
FOUNDATION WORK SHALL BE INSPECTED BY A QUALIFIED [CONSULTANT | ENGINEER] TO CONFIRM THE DESIGN ASSUMPTIONS PRIOR TO PLACING CONC
FOUNDATIONS (GENERAL)
SOIL CLASSIFICATION (CASSAGRANDE) IS SIMILAR TO xxx
REPORT ANY INCONSISTENCIES IN THE FOUNDATION SOIL MATRIX TO THE [CONSULTANT | ENGINEER] AN PROCEED ONLY ON HIS INSTRUCTIONS
IF UNSUITABLE MATERIAL OR GROUNDWATER IS ENCOUNTERED DURING FOUNDATION EXCAVATION, CONTRACTOR SHALL NOTIFY THE [CONSULTANT | ENGINEER] IMMEDIATELY BEFORE CONTINUING WITH CONSTRUCTION. OVER EXCAVATE AS REQUIRED AND INSTALL A PERIMETER DITCH AND PUMP AS REQD
PROTECT FOUNDATIONS AND ADJACENT SOIL AGAINST FREEZING AND FROST ACTION AT ALL TIMES DURING CONSTRUCTION
FOUNDATIONS SHALL BE PLACED:
NOT MORE THAN [3 | 75] OFF CENTRE
NOT MORE THAN 2% OF THEIR LENGTH OUT OF PLUMB
FOUNDATIONS SHALL BE CENTRED UNDER COLS AND WALLS UNLESS SHOWN OTHERWISE
THE CONTRACTOR SHALL MECHANICALLY VIBRATE ALL FOUNDATION CONC TO CONSOLIDATE IT AND TO CREATE AN UNINTERRUPTED BEARING SURFACE
FOUNDATIONS SHALL NOT BE CONSTRUCTED ON/IN FROZEN SOIL. THE CONTRACTOR SHALL ADEQUATELY PROTECT FOUNDATIONS AND FILL MATERIALS AGAINST FREEZING
ROCK OBSTRUCTIONS MAY BE PRESENT ON SITE. CONTRACTOR SHALL INCLUDE FOR THE REMOVAL OF ALL ROCK OBSTRUCTIONS ENCOUNTERED HAVING A MAXIMUM VOLUME OF 0.5 CUBIC METRES (17.7 CUBIC FEET)
PROVIDE [6FT | 1,9M] MIN OF BACKFILL FOR FROST PROTECTION U/N
WHERE REQD, THE CONTRACTOR WILL MAKE ALL NECESSARY PROVISIONS TO ALLOW DIRECT INSPECTION OF THE BEARING STRATA
THE GENERAL CONTRACTOR IS RESPONSIBLE FOR FOUNDING ELEVS FOR FOOTINGS AND CUT-OFF ELEVS FOR ALL PILES
FOUNDATIONS AND DRAINAGE (FOR PWF FOUNDATIONS)
SOIL BEARING PRESSURE IS 1500 PSF EXCEPT AS NOTED ON PLAN
MODULUS OF SUBGRADE REACTION IS 150 PCI EXCEPT AS NOTED ON PLAN
FOUNDATION BEARING SHALL BE ON UNDISTURBED NATIVE SOIL AND SHALL BE HAND EXCAVATED FOR THE FINAL [6 | 150]
RE: No Geotech Report
BA
RE: No Geotech Report
Actually, if you stamp and sign the plan you are definitely assuming liability for all your assumptions.
RE: No Geotech Report
cvg... depends on the matter and the level of sophistication of the client/contractor. At worst, it clouds the issue and at best it indemnifies you from claim. You have clearly stipulated that the information requires confirmation by Others.
Dik
RE: No Geotech Report
I have done foundations for small residences and remodels for years with the 2000, now 1500 and sometimes 1000 psf values mentioned with no problems.
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: No Geotech Report
It seems to me that our geotechnical bretheren work way to cheaply!
RE: No Geotech Report
RE: No Geotech Report
I guess you just have not dealt with the clients that I have... :)
Mike McCann
MMC Engineering
http://mmcengineering.tripod.com
RE: No Geotech Report
Always insist on a report, I dont take jobs without them anymore. Not work the headache of a cheap owner.