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Home My WebLink AboutGeotechnical ReportColleen Wirth 6eeþaLn,ào/ 1*a¿d @"* From: Sent: To: Cc: Subject: Attachments: Vance King <vanceking@civcoengineering.com> Friday, November 17,2023 5:06 PM Colleen Wirth Douglas, Staci RE: BLMF-1 1-23-8415 -CMH Homes TBD CR 237 Silt Colorado is now UNDER REVIEW 231009 TBD cr 237 soil rpt (SM) - shawn.pdf Here you go. Have a nice weekend Thanks, Vance King, CIVCO Engineering, futc. PO Box 1758 Vernal, UT 84078 435-789-5448 From : Col leen Wirth <cwirth @ga rfie ld-county.com> Sent: Friday, November L7,2023 2:40 PM To: Vance King <vanceking@civcoengineering.com> Cc: Douglas, Staci <Staci.Douglas@ClaytonHomes.com> Subject: BLMF-1L-23-8415 -CMH Homes TBD CR 237 Silt Colorado is now UNDER REVIEW ',+:{¿ You don't often get email from cwirth@garfield-county.com Learn why this is important :rì, BLMF-ll-23-84t5 CMH Homes TBD CR237 Silt, Lot 2 Grand Hogback Subdiv Exemption Courtesy Message for Vance King, cc: Staci Douglas, Hello, l'm fairly well through the bu¡lding and zoning reviews for Lot 2 outside Silt, Colorado. l'm needing to receive and review an electronic copy of CIVCO Engineering prepared geotechnical report as referenced in stamped foundation plan S1.0 dated LOIO9/2O23. I need to place the geotechnical report in the building file records in order to satisfy a zoning condition before releasing this permit. Unfortunately, the report was not found in submittal materials. Please forward the report to me at: cwirth@garfield-countv.com. Have a good weekend, Colleen W¡rth Building Plans Examiner Garfield County Community Development 1"08 8th Street, Suite 401 (970) 945-1377 ext t6LO cwirth @ga rfield-countv.com 1 2 6e"þclàt¿z/ CTVCO Engineering,n#trÇrra/o'*tÞ^-- dee,gnCivil Engineering Consultonts P.O. Box t758 3ó5 West 50 North, Suite W-l Vernql, Utoh 84078 October 9, 2023 Shawn Ruse Clayton Homes 671 23 Road Grand Junction, CO 81505 Dear Shawn, Subiect Soil lnvestigation -Residence at TBD CR237, Silt' CO I am writing this letter to report the findings of a soil investigation that was conducted at the proposed site for the residence at TBD County Road 237, Silt, Colorado. The investigation entailed the analysis of one soil sample that was taken from the proposed construction site at approximately the bearing depth of the proposed foundation. Testing of the soil sample included a sieve analysis and Afterberg Limits testing. The test results were used to classifl the soil sample as 'SM-Silty Sand with Gravel' according to the Unified Soil Classification System. Copies of the soil data are included with this letter. SM soils are generally silty sands. Literature suggests that loose SM soils are likely to have bearing capacities in the range of 3,000 psf. RecognÞing that no specific bearing capacity testing was performed, I recommend that a more conservative bearing capacity of 1500 psf be used for design purposes. Over the years, several studies have been conducted to conelate soil expansiveness to atterberg limit data. According to one study, soils with Liquid Limits less than 50% and Plasticity lndices that less than 25%, generally have a low potential for expansion (Snethen, Johnson, and Patrick, 1977). Ihe soil sample tested was found to have no measurable Liquid Limit or Plasticity lndex. Thus, according to the referenced study, the soil in question is anticipated to have a low expansion potential. lt should be noted that Atterberg Limits testing does not address mineralogy and thus may have a limited ability to reliably predict soil expansion potential. SM soils are often susceptible to frost heave. Therefore, it is important that structuralfoundations bear belou¡ the local frost penetration depth or be frost-protected with insulation. Frost heave results from soil moisture expanding as it freezes. Therefore, every effort should be taken to limit soil moisture in the vicinity of foundations. Walkways, driveways, and ground surfaces should be graded to flow away from the foundation. Gutter down-spout outlets should discharge at least five feet away from the foundation. Vegetation requiring significant watering should not be planted near the foundation. No testing was done to determine the soil's collapse potential. ln my experience, foundation failures due to soil collapse are generally even more catastrophic than failures due to soil expansion. ln every instance of soil collapse failure that I have investigated, the damaged home was located at the mouth of a pronounced drainage, such as a canyon or gully where the soil has been deposited alluvially by intermittent runoff water flows. Alluvially deposited soils are typically not very dense and derive their strength from mineral bonds that form between soil particles. When these soils become wet, the mineral bonds dissolve, allowing the soil particles to consolidate (collapse) under any load that is more than that which existed when the mineral bonds originally formed. Veriff that the project site is not at the mouth of any obvious drainage. As with frost heave, limiting the introduction of moisture to the soil is key to lessening the risk of soil collapse failure. Phone (435)789-5448 * Foc (435F89-Æ5 Emoil: voncekíng@civcoengineering.com . Page2 October 9, 2023 ln summary, the soil under the proposed foundation was not specifically tested to determine expansiveness but was found to have properties consistent with soils having very little expansion potential. Likewise, the soilwas not specifically tested to determine bearing capacity but was ficund to be of a type having characteristic bearing capacities in the range of 3000 psf. For design purposes, ¿ 1500 psf bearinq capacity is recommended. The homeowner should make every effort to keep moisture from being introduced iıthe soil near the foundation. Any future purchaser of the home should be apprised of the underlying soil characteristics and the importance of keeping moisture away from the foundation. This concludes my report. Please note that this investigation was performed for the purpose of providing general information regarding the soil underlying the proposed home and makes no prediction of foundational performance. This report should not be regarded as documentation of a geotechnical investigation as I am not a geotechnical engineer, and this study was not conducted to any generally accepted standard of geotechnical engineering prac{ice. Please contact me if you have questions regarding this report. Sincerely, VanceV. King, PE Engineer CIVCO Engineering, lnc. Enclosure Cc: Project File Cl. C. Testing. lnc 2944 South 1500 East VERNAL, UTAH 84078 Phone (435) 789-0220 Fax (435) 781-1876 SIEVE ANALYSIS AND ATTEBERG LIMITS cR237 S|LT CO O.C.TESTING - Project No. or Client: Material Type: Distence from CL: MF= NATIVE Depth: _ Date Sampled Tested By Stations: Date Tested:9t2912023 AASHTO T-89 & T.9O Atterbero L¡mit Liqu¡d L¡mii lruv Plastic L¡m¡t lrup Plast¡c index lrup Clessifìel¡o¡lsu - srlw sAND wrrH cRAVEL -rÍ4 Moisture Data WetWt.1237.1 Drv vvt.1182.5 H20 Wt.54.6 H2O o/o 4.600/o Washed Drv \M.902.8 AASHTO T-27 Coarse Gradation Sieve Size Weight Ret.7o Ret. 7o Total Passino Sieve Size Specs 3" 05mm) 2" (somm)2', 1.5" (37.5mm)1.5' 1" (zsmm)0 0 100 1 3/4" ltsmm¡205.3 17.4 82.6 314" 112" (12.sñn)1t2" 3/8" (g.smm)3/8' #4 (4.75mm)122.7 10.4 72.2 #4 -144 ø.7sñn) WETWT, -ll4 (1smm], DRYWT. Total Fine Gradation Sieve Size Weight Ret. 0 7o Ret. 0 % Pass ll4 (llmn) #8 (z.gsmm) #10 (2.omm)60.4 5.1 67.1 #16 f .18mm) #20 (ssoFm)34.2 2.9 64.2 #30 (600Fm) ll4o øzlpn\45.8 3.9 60.3 #50 (3oopm) #60 (2sopm) #80 lsopm) #1 00 (1sorm)218.8 18.5 41.4 #200 Ospm)200.9 17 24.4 -#200 (75um)294.4 24.9 Total Remarks