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HomeMy WebLinkAboutSoils Report 06.28.2017Huddleston -Berry Engineering & Testing, LLC Clayton Homes 671 23 Road Grand Junction, Colorado 81505 640 White Avenue Grand Junction, Colorado 81501 Phone: 970-255-8005 Fax: 970-255-6818 Info@huddlestonberry.com June 28, 2017 Project#01303-0009 Attention: Mr. David Mahovsky JUN 292011 Subject: Geotechnical Investigation Gin ,� , 4' 499 Hidden Valley Drive Glenwood Springs, Colorado Dear Mr. Mahovsky, This letter presents the results of a geotechnical investigation conducted by Huddleston -Berry Engineering & Testing, LLC (HBET) at 499 Hidden Valley Drive in Glenwood Springs, Colorado. The site location is shown on Figure 1. The proposed construction is anticipated to consist of a single family residence. The scope of our investigation included evaluating the subsurface conditions at the site to aid in developing foundation recommendations for the proposed construction. Site Conditions At the time of the investigation, the site was open and fairly flat. Vegetation consisted primarily of weeds and grasses. The site was bordered to the west and southwest by existing residences, to the south by a vacant lot, and to the north and east by Hidden Valley Drive. Subsurface Investigation The subsurface investigation included two test pits as shown on Figure 2 — Site Plan. Test Pits TP -1 and TP -2 were excavated to depths of 9.5 and 8.0 feet below the existing ground surface, respectively. Typed test pit logs are included in Appendix A. As indicated on the logs, the subsurface conditions at the site were slightly variable. However, the test pits generally encountered 1.0 to 1.5 feet of topsoil above red, moist, medium dense silty sand soils to the bottoms of the excavations. However, in TP -1, a layer of red, moist, dense sandy gravel and cobbles was present from 3.0 to 5.5 feet. Groundwater was not encountered in the subsurface at the time of the investigation. 499 Hidden Valley Drive #01303-0009 06/28/17 Huddlecton•Berrr �n{+.w.n�fi Iormt. 11[ Laboratory Testing Laboratory testing was conducted on samples of the native soils encountered in the test pits. The testing included grain size analysis, Atterberg limits determination, natural moisture content determination, water soluble sulfates content determination, and maximum dry density and optimum moisture content (Proctor) determination. The laboratory testing results are included in Appendix B. The laboratory testing results indicate that the native sand soils are non -plastic. Based upon our experience in the vicinity of the subject site, the native sand soils may have a slight potential for collapse. Water soluble sulfates were not detected in the site soils. Foundation Recommendations Based upon the results of the subsurface investigation and nature of the proposed construction, shallow foundations are recommended. Spread footings and monolithic (turndown) structural slabs are both appropriate foundation alternatives. However, in order to provide a uniform bearing stratum and limit the potential for excessive differential movements, it is recommended that the foundations be constructed above a minimum of 24 -inches of structural fill. The native sand soils, exclusive of topsoil, are suitable for reuse as structural fill. The native gravel soils are also suitable for reuse as structural fill, provided particles in excess of 4 -inches in diameter are removed. Imported structural fill should consist of a granular, non -expansive, non - free draining material such as crusher fines or CDOT Class 6 base course. Unless it can be demonstrated that the materials are not free -draining, pit -run materials should not be used as structural fill. Prior to placement of structural fill, it is recommended that the bottom of the foundation excavation be scarified to a depth of 6 to 9 inches, moisture conditioned, and compacted to a minimum of 95% of the standard Proctor maximum dry density, within ± 2% of the optimum moisture content as determined in accordance with ASTM D698. Structural fill should extend laterally beyond the edges of the foundation a distance equal to the thickness of structural fill. Structural fill should be moisture conditioned, placed in maximum 8 -inch loose lifts, and compacted to a minimum of 95% of the standard Proctor maximum dry density for fine grained soils and modified Proctor maximum dry density for coarse grained soils, within ± 2% of the optimum moisture content as determined in accordance with ASTM D698 and D1557, respectively. For structural fill consisting of the native soils or imported granular materials and foundation building pad preparation as recommended, a maximum allowable bearing capacity of 1,500 psf may be used. In addition, a modulus of subgrade reaction of 150 pci may be used for structural fill consisting of the native soils and a modulus of 250 pci may be used for structural fill consisting of crusher fines or base course. Foundations subject to frost should be at least 36 - inches below the finished grade. X:\2008 ALL PROJECTS\01303 - Clayton Homes\01303-0009 499 Hidden Valley\200 - Geo\01303-0009 LR062817.doc 2 499 Hidden Valley Drive #01303-0009Huddleston-Berry 06/28/17 , Ffismnanr c rn;ni,11 Any stemwalls or retaining walls should be designed to resist lateral earth pressures. For backfill consisting of the native soils or imported granular, non -free draining, non -expansive material, we recommend that the walls be designed for an active equivalent fluid unit weight of 45 pcf in areas where no surcharge loads are present. All at -rest equivalent fluid unit weight of 65 pcf is recommended for braced walls. Lateral earth pressures should be increased as necessary to reflect any surcharge loading behind the walls. As discussed previously, water soluble sulfates were not detected in the site soils. However, water soluble sulfate concentrations can vary widely in Western Colorado. Therefore, at a minimum, Type I-II sulfate resistant cement is recommended for construction at this site. Non -Structural Floor Slab and Exterior Flatwork Recommendations In order to reduce the potential for excessive differential movements, it is recommended that non-structural floating floor slabs be constructed above a minimum of 12 -inches of structural fill with subgrade preparation, structural fill materials, and fill placement be in accordance with the Foundation Recommendations section of this report. It is recommended that exterior flatwork be constructed above subgrade soils, below the topsoil and/or fill, that have been scarified to a depth of 12 -inches, moisture conditioned, and compacted to a minimum of 95% of the standard Proctor maximum dry density, within ±2% of the optimum moisture content as determined in accordance with ASTM D698. Drainage Recommendations Grading and drainage are critical_for the long-term pertbrmance of the structure and grading around the structure should be designed to carry precipitation and runoff away from the structure. It is recommended that the finished ground surface drop at least twelve inches within the first ten feet away from the structure. It is also recommended that landscaping within five feet of the structure include primarily desert plants with low water requirements. In addition, it is recommended that automatic irrigation, including drip lines, within ten feet of foundations be minimized. HBET recommends that downspout extensions be used which discharge a minimum of 10 feet from the structure or beyond the backfill zone, whichever is greater. However, if subsurface downspout drains are utilized, they should be carefully constructed of solid -wall PVC and should daylight a minimum of 15 feet from the structure. In addition, an impermeable membrane is recommended below subsurface downspout drain lines. Dry wells should not be used. As discussed previously, groundwater was not encountered at the site. However, a perimeter foundation drain is recommended to limit the potential for surface moisture to impact the structure. In general, the perimeter foundation drain should consist of prefabricated drain materials or perforated pipe and gravel systems with the flowline of the drain at the bottom of the foundation (at the highest point). The perimeter drain should slope at a minimum of 1% to daylight or to a sump. An impermeable membrane is also recommended at the base of the drain to limit the potential for moisture to infiltrate into the subsurface below the foundations. X:\2008 ALL PROJECTS\01303 - Clayton Homes \01303-0009 499 Hidden Valley\200 - Geo\01303-0009 LR062817 doe 3 499 Hidden Valley Drive #01303-0009 06/28/17 Huddleston -Berry Fnglme.ln, d i cuiry, 1.1C General Notes The recommendations included above are based upon the results of the subsurface investigation and on our local experience. These conclusions and recommendations are valid only for the proposed construction. As discussed previously, the subsurface conditions at the site were slightly variable. However, the precise nature and extent of subsurface variability may not become evident until construction. The recommendations contained herein are designed to reduce the risk and magnitude of structural movements and it is extremely critical that ALL of the recommendations herein be applied to the design and construction. However, HBET cannot predict long-term changes in subsurface moisture conditions and/or the precise magnitude or extent of any volume change in the native soils. Where significant increases in subsurface moisture occur due to poor grading, improper stormwater management, utility line failure. excess irrigation, or other cause, during or after construction. significant movements are possible. In addition, the success of the structure foundations, slabs, etc. is critically dependent upon proper construction. Therefore, HBET should be retained to provide materials testing, special inspections, and engineering oversight during ALL phases of the construction to ensure conformance with the recommendations herein. We are pleased to be of service to your project. Please contact us if you have any questions or comments regarding the contents of this report. Respectfully Submitted: Huddleston -Berry Engineering and Testing, LLC Michael A. Berry, P.E. Vice President of Engineering X:\2008 ALL PROJECTS\01303 - Clayton Homes\01303-0009 499 Hidden Valley\200 - Geo\01303-0009 LR062817.doc 4 FIGURES CGarfield County Garfield County Land Explorer Garfield County, Colorado Garfield County Land Explorer Printed by Web User 1 1 inch = 1,505 feet 1 inch = 0.28 miles 02 0a it FIGURE 1 Site Location Map 0.8 Miles Garfield County Colorado Garfield County www.garfleld-county.com Colorado Disclaimer This Is • oo,nplletbn of records es they appear In the Garfield County Offices effecting the area shown. This d'swine Is to be used only for reference purposes end the County Is not responsible for env beccuredes herein contained. © Copyright Garfield County, Colorado 1 All Rights Reserved Printed: 6/28/2017 at 5:23:27 PM I. \ aavrasaem ugld NTS Z 1xnDi.3 an. follw Hca , era .frfrAre Ar ►Og z`9 /07 Z. mai a ouluakep aan.w •i.w..wvs�w ua.+a./r+a }.o. v.cna Mwp�� ewiu..ra sNe,nis��T Ca ..1.I[.........7pa _i u uw o.ro.u+t APPENDIX A Typed Test Pit Logs GEOTECH BH COLUMNS 01303-0009 499 HIDDEN VALLEY DR.GPJ GINT US LAB.GDT e,27/17 F f i 1 i 1 1 1 1 1 1 1 1 w 01 o 1 I 1 1 N in :o DEPTH o (ft) DATE STARTED 6/13/17 COMPLETED 6/13/17 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client GROUND WATER LEVELS: EXCAVATION METHOD Backhoe AT TIME OF EXCAVATION dry LOGGED BY CM CHECKED BY MAB AT END OF EXCAVATION dry NOTES AFTER EXCAVATION -- Huddleston-Bevy Engineering & Testing, LLC TEST PIT NUMBER TP -1 640 White Avenue, Unit B PAGE 1 OF 1 Grand Junction, CO 81501 " SBA 970-255-8005 •••- 970-255-6318 CLIENT Clayton Homes PROJECT NAME 499 Hidden Valley Drive PROJECT NUMBER 01303-0009 PROJECT LOCATION Glenwood Springs, CO GRAPHIC �.An� ..�� .•�A.� .�� LOG Bottom of test pit at 9.5 feet. Silty SAND (sm), red, moist, medium dense Sandy GRAVEL and COBBLES (gw), red, moist, dense MATERIAL DESCRIPTION Silty SAND with Organics (TOPSOIL) Silty SAND (SM), red, moist, medium dense ''`" Lab Classified GB1 CA -. O m SAMPLE TYPE NUMBER RECOVERY % (RQD) BLOW COUNTS (N VALUE) POCKET PEN. (tsf) DRY UNIT WT. (pcf) N MOISTURE CONTENT (%) z -13 LIQUID LIMIT > 1 z PLASTIC LIMIT —1 CO z PLASTICITY INDEX cnm X 0 a N FINES CONTENT (%) GEOTECH BH COLUMNS 01303-0009 499 HIDDEN VALLEY DR.GPJ GINT US LAB GDT 6/27/17 1 I I [ 1 ern L 1 L 1 1 1 I w a 1 1 1 1 1 1 1 T N it 1 I o DEPTH o (ft) DATE STARTED 6/13/17 COMPLETED 6/13/17 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR Client GROUND WATER LEVELS: EXCAVATION METHOD Backhoe AT TIME OF EXCAVATION dry LOGGED BY CM CHECKED BY MAB AT END OF EXCAVATION dry NOTES AFTER EXCAVATION --- ,, Fluddlton-BcnyEngineering & Testing, LLC TEST PIT NUMBER TP -2 640 White Avenue, Unit B PAGE 1 OF 1 YGrand Junction, CO 81501 970-255-8005 -•- •• 970-255-6818 CLIENT Clayton Homes PROJECT NAME 499 Hidden Valley Drive PROJECT NUMBER 01303-0009 PROJECT LOCATION Glenwood Springs, CO [. GRAPHIC LOG y• I o O O 3 O m o 1 m P3 O W CD > Z 0 3 d 3 O N. 3 a E 3 n m y O 0) > Z 0 0 N n �+ q 0 0) O 0 MATERIAL DESCRIPTION SAMPLE TYPE NUMBER RECOVERY % (RQD) BLOW COUNTS (N VALUE) POCKET PEN. (tsf) DRY UNIT WT. (pcf) MOISTURE CONTENT (%) LIQUID LIMIT ATTERBERG LIMITS PLASTIC LIMIT PLASTICITY INDEX FINES CONTENT (%) APPENDIX B Laboratory Testing Results encr• Huddleston -Berry Engineering & Testing, LLC GRAIN SIZE DISTRIBUTION 640 White Avenue, Unit B , fit5' Grand Junction, CO 81501 0 970-255-8005 - •, '" 970-255-6818 CLIENT Clayton Homes PROJECT NAME 499 Hidden Valley Drive PROJECT NUMBER 01303-0009 PROJECT LOCATION Glenwood Springs, CO U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS I HYDROMETER 6 4 3 2 1.5 13/4 316 3 4 6 610 1416 20 30 40 50 60 100140200 100 1 I 1 l I I I I I I I i 1 95 lk 90 85 80 75 1- \it 70 - 1- 65 1 c7 60 ui\\P Y 55 m Ce w50 z IL r 1- 45 z w v 40 w a 35 30 25 20 15 10 5 0 _ _ 100 10 0 i GRAIN SIZE IN MILLIMETERS 0.01 0.001 GRAVEL SAND COBBLES coarse fine coarse medium l fine SILT OR CLAY 11 Specimen Identification Classification LL PL PI Cc Cu • TP -1, GB1 6/2017 SILTY SAND(SM) NP NP NP Specimen Identification D100 D60 D30 D10 %Gravel %Sand %Silt %Clay • TP -1, GB1 6/2017 12.5 0.183 7.9 50.3 41.8 ys' CLIENT PROJECT Huddleston-Beny Engineering & Testing, LLC 640 White Avenue, Unit B (;rand Junction, CO 81501 970-255-8005 970-255-6818 Clayton Homes PROJECT MOISTURE NAME LOCATION -DENSITY RELATIONSHIP 499 Hidden Valley Drive NUMBER 01303-0009 PROJECT Glenwood Springs, CO DRY DENSITY, pcf a a a a a a a a a CO CO O 0 a a N N W G) 4=6U1 O 0 0 CJS 0 CT O 01 0 CJS 0 U7 0 Sample Sample Source Description Test Method' Maximum Optimum Date: No.: of Material: of Material: Dry Water Density Content GRADATION #200 6/13/2017 17-0342 TP -1 SILTY SAND(SM) ASTM D698A RESULTS ATTERBERG RESULTS 119.5 PCF (% LIMITS 100% Gravity 2.80 2.70 2.60 PASSING) 3/4" \\ 11.5 \\ #4 92 \\\ 42 100 LL Curves for PL PI to: ,D. � \ �'� \, \ r NP NP Specific of NP Saturation Equal \\N \.. \ \\ \ \ \ \\ "\\\ 5 10 15 20 25 30 WATER CONTENT, %