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Home My WebLink AboutSoils Report 5.15.2018CTVCO Engine ering, Inc. Civil Engineering Consultants P.O. Box 1758 365 West 50 North, Suite W-l Vernql, Utoh 84078 May 15,2018 Richard Ruse Clayton Homes 671 23 Road Grand Junctlon, CO 81505 Dear Richard, subjecft soil lnvestigation - Talbot ResÍdence at rBD llury 6, New casüe, Go I am writing this letter to report the findings of a soil investigation that was conducted at the proposed site for the Talbot residence that is to be built at TBD Highway 6, New Castle, Colorado. The invesligation 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 Atterberg Limits testing. The results of the soil testiñg were used to classifu the soil sample as 'SC' according to the Unified Soil Classification S¡ætem. A copy of the soil ¿ãta is included with thís letter. SC soils are mixtures of sands, and fine soils, Bearing capacities for SC soils are typically 3000 psf for loose soils. Recognizing that no specifìc testing was conducted to determíne the ïoils ãctual bäaríng capacity, I recommend that a smaller bearing capacity of 1500 psf be used for design of the home'ã foundation. Over the years, a number of studies have been conducted in an effort to conelate soil shrink-swell potential (i.e. expansiveness) to atterberg limit data, According to one study, soils having liquid limits less than 35% and plasticity indexes less than 12Yo, are generàly non-expañsive, (Snethén, Johnson, and Patrick, 1977). The tested soil sample had a measured liquid limit of 367o and a plasticity index of 11% and thus is anticipated to have a very low potential to be expansive. Please note that Atterberg limits testing does not address mineralogy and thus may be limited in its abillty to reliably predict soi shrink-swell potential. Though the Atterberg Limits testing suggests a non€xpansive soil, frost heave could still cause problems for the foundation. Foundalions should extend to below frost depth or be frost-protected by some other means. Water should be kept away from the foundations. Walkways, driveways, anå ground surfaces should be graded to flow away from the foundation. Gutter down,sþout ouflets should be kept at least fìve feet away from the foundation. Vegetation requiring sígnificant 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 moutñ of a pronounced drainage, such as a canyon or gully where the soil has been deposited alluvially by intermittent runoff water flows. Alluviallydeposited soils are typically nol 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 (i.e. collapse) under any load that is in excess of that which existed when the mineral bonds originally formed. Phone (435P89-544r8 * Fox (435[89-4485 Emqil : vonceking@cívcoengineering.com . Page 2 May 15,201g Verify that the project site is not at the mouth of any obvious drainage, The aforementioned methods for lowering the risk of frost heave are also key to lessening the risk oisoil collapse failure. ln summary the soíl under the proposed foundation was not specifically tested to determine expansiveness but was found þ have properties consistent with soils having a lbw expansion potential. Likewise the soil was not specifically tested to determine bearlng capacity bút was foun¿ to be of a type having characteristic bearing capacities in the range of 3000 þsf.' FoiOesign purposes, a 1500-psf bearing capacity is recommended. The home owner should make every effırt io k'eep moisture frombeing introduced to the soil near the foundation, Any future purchaser oithe 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 thís investígation was performed for the purpose ofproviding general information regarding the soil underlying the proposed home and makes noprediction of foundational performance. Please contact me if you havb questions regarding thii report. Sincerely, Vance V. King, PE Engineer CIVCO Engineering, lnc. Enclosure Cc:Project Fife Cl, C. Testing. lnc 2944 S 1500 E VERNAL, UTAH 84078 Phone (435) 789-022A Fax (435) 781-1876 SIEVE ANALYSIS AND ATTEBERG LIMITS CIVCO Enqlneerinq -Talbot. Garfield Countv. CO 0. c- ÍE$Tlr{ff AASHÏO T-27 Coarse Gradation Sieve Size Weight Ret.% R€t. o/of olal Pass¡na Sieve Size Spacs 3" (?omm)3', 2" lsomm¡z', 1.5" (g¡.smm)1.5' l" ¡asmn¡ 3/4'(tgnm)314" '1i2" lrz.smm¡112" 318'1s.smm¡0 100.0 3/8' #4 {4.75mm)244.2 25.3 74.7 #4 #4 (4.zsmm) WET WT, i#4 lr,zsmm¡ BRY WT. Totãl Project No. or Client: Materia¡ Type: D¡stanc€ from CL: native - unified soil classifìcation Deplh:Date Sampled Stations Date Tasted:5t512018 AASHIO T-89 & T.so Atteóors Limit -lquld Llm¡t 36 Plætlc Llmlt 25 Plasuc lndex 11 Cla!sit¡c¡üo¡gilty, clayey send +#4 Moíslure Data wr. wt,1 wr. o/o 2,4 Washed Dry Wt.507.7 MF=T€sted By CN Fine Grãdalion Size Weight Ret.% Ret.7o Pass #4 (4.7snn) fl8 (2.3smn) #l01e.omm¡44.4 5.5 69.2 #16 (1.rsmm) #20 loso¡rm¡39.7 4.9 64.3 #30 (soorm) åq0 (42srm)39.2 4.9 59.4 È¡50 {¡oorm) å60 (25orm) #80 lteo¡m¡ #1 00 lrso¡m¡ #200 (rspm)169,6 21.0 38.4 #200 l75um)309.6 38.4 Total Rema¡ks SOILCLASSIFICATIONfun|fìedì