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HomeMy WebLinkAboutEngineer Report 12.09.2013.pdfHuddleston -Berry Engineering & Tesl ing. LLC Cheryl Gonzalez 246 West Capital Court New Castle, Colorado 81647 Subject: Geotechnical Investigation and ISDS Feasibility 350 Cedar 1 -sills Road Silt, Colorado Dear Ms. Gonzalez, 640 White Avenue Grand Junction, CO 81501 Phone: 970-255-8005 Fax: 970-255-6818 11uddlestonBerry@biesnan,nel www.HBET-GJ.com December 9, 2013 Project1101313-0001 This letter presents the results of a geotechnical investigation conducted by I-Iuddleston-Berry Engineering & Testing, LLC (1-IBET) at 350 Cedar Hills Road in Silt, Colorado. The site location is shown on Figure 1 — Site Location Map. The proposed construction is anticipated to consist of a single -fancily residence. The scope of our investigation included evaluating the subsurface conditions at the site to aid in developing foundation recommendations for the proposed construction. In addition, the site was evaluated for Individual Sewage Disposal System (1SDS) feasibility. Site Conditions At the time of the investigation, the site was generally open and sloped down to the west. Vegetation consisted primarily of grass and sage brush. The site was bordered by Cedar Hills Road to the west, by existing residences to the south and east, and by a vacant lot to the north. Subsurface Investigation The subsurface investigation included four test pits as shown on Figure 2 — Site Plan. The test pits were excavated to depths of between 3.0 and 10.0 feet below the existing ground surface. 'l'yped test pit Togs are included in Appendix A. As indicated on the logs, the subsurface conditions at the site were fairly consistent. The test pits generally encountered 1.0 foot of sandy lean clay with organics topsoil above brown, dry to moist, medium stiff to hard sandy lean clay to the bottoms of the excavations. Groundwater was not encountered in the test pits at the time of the investigation. 350 Cedar Hills Road #01313-0001 12/09/13 Huddlcslon.Bem .n .>ui Laboratory Testing Laboratory testing was conducted on samples of the native soils collected from the test pits. The testing included grain -size analysis, Atterberg limits deterntination, natural moisture and density determination, swelUconsolidation testing, water soluble sulfates content determination, and maximum dry density/optimum moisture (Proctor) determination. The laboratory testing results are included in Appendix B. The laboratory testing results indicate that the native clay soils are slightly plastic. In addition, the sand soils were shown to be moderately collapsible with up to approximately 5.5% collapse measured in the laboratory. Water soluble sulfates were detected in the site soils in a concentration of 0.03%. 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 slab foundations are both appropriate alternatives. However, as discussed previously, the native soils are slightly collapsible. Therefore, in order to reduce the risk of excessive differential settlements, it is recommended that the foundations be constructed above a minimum of 24 - inches of structural fill. The native clay soils, exclusive of topsoil, are suitable for reuse as structural 611. Imported structural fill should consist of a granular, non -expansive, non -free draining material such as pit - run, crusher fines, or CDOT Class 6 base course. However, if pit -run is used for structural till, a minimum of six inches of crusher tines or Class 6 base course should be placed on top of the pit run to prevent large point stresses on the bottoms of the footings due to large particles in the pit - run. Prior to placement of structural fill, it is recommended that the bottom of the foundation excavation be scarified to a depth of 6 to 8 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 90% of the modified Proctor maximum dry density for coarse grained soils, within 2% of the optimum moisture content as determined in accordance with ASTM D698 and D1557C, 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, pit -run, or base course. Footings subject to frost should be at least 36 inches below the finished grade. q x2003 ALL PROJECTS 0131) • Chepl Go let 01313.0001 350 Cedar Hills Road 200 • Gro'01113 R001 11112031dee 2 350 Cedar I lilts Road #01313-000I 12/09/13 Huddleston -Hem' As discussed previously, water soluble sulfates were detected in the site soils in a concentration of 0.03%. This concentration of sulfates represents a negligible degree of potential sulfate attack on concrete exposed to the native soils. Therefore, sulfate resistant cement may not be required for construction at this site. Any stemwalls, basement walls, 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 equivalent fluid unit weight of 65 pef in areas where no surcharge loads are present. Lateral earth pressures should be increased as necessary to reflect any surcharge loading behind the walls. Floor Slab and Exterior Flatworlc Recommendations In order to limit the potential for excessive differential movements of slabs -on -grade it is recommended that non-structural floor slabs and/or exterior flatwork be constructed above the native soils, below the topsoil, 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 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. Downspouts should empty beyond the backfill zone. 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 irrigation within ten feet of foundations be minimized. As discussed previously, shallow groundwater was not encountered at the time of the investigation. However, if a structural floor and crawlspace or basement are utilized, a perimeter foundation drain is recommended. 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 least one foot below the bottom of the foundation (at the highest point). The perimeter drain should slope at a minimum of 1.5% to daylight or to a sump. Gravel and/or prefabricated drain materials should extend along basement walls to within 24 to 36 -inches of the finished ground surface. In addition, an impermeable membrane is recommended at the base of the drain to limit the potential for excess moisture to infiltrate below the foundations. Individual Sewage Disposal In order to evaluate the feasibility of the site soils for on-site sewage disposal, percolation testing was conducted in the vicinity of the proposed absorption bed in TP -2 through TP -4. The percolation rate in the native clay soils was determined to range from 7 to 16 minutes -per -inch with an average of approximately 11 minutes -per -inch. The percolation testing data is included in Appendix C. In general, a percolation rate of between 5 to 60 minutes -per -inch is required for the subsurface to be deemed suitable for on-site sewage disposal. Therefore, the native clay soils are suitable for on-site sewage disposal. S. 2003 ALL PROJECTS01313 - C4tp1 Gonralei 013 13.0001 350 Cedar HMI Road 200 • G(401113-0031 LR110313 doc 3 350 Ccdar I fills Road #01)13.0001 12/09/13 Ilu Idleston-0ciy In addition to the percolation rate of the subsurface materials, the seasonal high groundwater elevation is an important factor in determining the suitability of the site for Individual Sewage Disposal Systems. For iSDS suitability, the seasonal high groundwater elevation should be at least four feet below the bottom of the proposed absorption bed. As indicated previously, groundwater was not encountered at the time of the investigation. in general, based upon the results of the subsurface investigation, HBET believes that the seasonal high groundwater elevation at this site is deeper than 10.0 feet below the existing ground surface. 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 fairly consistent, However, the precise nature and extent of any subsurface variability may not become evident until construction. As a result, it is recommended that a representative of HBET observe the foundation excavation prior to structural fill placement to verify that the subsurface conditions are consistent with those described herein. In addition, it is recommended that a representative of HBET test compaction of structural fill materials. Also as discussed previously, collapsible soils are present at the site. The recommendations contained herein are designed to reduce the potential for excessive differential movements; however, HBET cannot predict long-term changes in subsurface moisture conditions and/or the precise magnitude or extent of volume change. Where significant increases in subsurface moisture occur due to poor grading, improper stormwater management, utility line failure, excess irrigation, or other cause, either during construction or the result of actions of the property owner, significant movements are possible. We are pleased to be of service to your project. Please contact us if you have any questions or continents regarding the contents of this report. Respectfully Submitted: Huddleston -Berry Engineering and Testing, LLC Michael A. Berry, P.E. Vice President of Engineering W:' 2003 ALL PROJECTS 01313 - Chcpl Gonealei 0131).0001350 Cedar 111115 Read ]W - Gni 01313 0001 LRI20313 de: 4 FIGURES Burning_ 773° i'!Iountain C L_ 1 L_./1 do \, . sew; • 35600 pp= LowEff iN RI_ o �\I civ—'\• _• `lir✓�` / Ai �c- \� I \ 1 �j �•v l \\� OSCS New Castle, Colorado Quadrangle, 7.5 -Minute 1 r v 7 - � g ule Series 1962,1 holo a ;sed 198 \\bi //1 r 5 • FIGURE 1 Site Location Map .r( APPENDIX A Typed Test Pit Logs eqf--..,,,Huddleston-Berry , P Engine ring & Testing, LLC 640 White Avenue, Unit B Grand Junction, CO 81501 970-255.8005 970-255-6818 Gonzalez PROJECT NAME LOCATION TEST PIT NUMBER TP -1 PAGE 1 OF 1 350 Cedar Hills Rd •' CLIENT PROJECT Cheryl NUMBER 01313-0001 PROJECT Sill, CO DATE EXCAVATION EXCAVATION LOGGED NOTES STARTED BY 11/6/13 COMPLETED 11/6/13 GROUND ELEVATION WATER LEVELS: TIME OF EXCAVATION END OF EXCAVATION EXCAVATION TEST PIT SIZE CONTRACTOR R&S Trucking GROUND dry METHOD Backhoe AT NWB CHECKED BY MAB AT dry AFTER --- °- ° 0.0 O °-O O MATERIAL DESCRIPTION SAMPLE TYPE NUMBER RECOVERY % (ROD) BLOW COUNTS (N VALUE) POCKET PEN. (tsf) z it a' 0 MOISTURE CONTENT f%) ATTERBERG LIMITS FINES CONTENT (%) of FF 5n a 56 g 6 ! -= c..,ir; Sandy Lean CLAY with Organics (TOPSOIL), brown, moist 2.5 Sandy Lean CLAY (CL), grayish brown, dry, hard N MC 89 7 5.0 //// "' GB1 Lab Classified *" G GB 7 28 15 13 52 7.5 Bottom of lest pit at 9.5 feet. ,� CLIENT PROJECT "O , A -cot! Cheryl Huddleston -Berry Enolneering & Testing, LLC 640 White Avenue, Unit B Grand Junction, CO 81501 970-255.8005 970-255-6818 Gonzalez PROJECT NAME LOCATION TEST PIT NUMBER TP -2 PAGE 1 OF 1 350 Cedar Hills Rd NUMBER 01313-0001 PROJECT Silt, CO DATE EXCAVATION EXCAVATION LOGGED NOTES STARTED BY 11/6/13 COMPLETED 1116/13 GROUND ELEVATION WATER LEVELS: TIME OF EXCAVATION END OF EXCAVATION EXCAVATION TEST PIT SIZE CONTRACTOR R&S Trucking GROUND dry METHOD Backhoe AT NWB CHECKED BY MAB AT dry AFTER --- x W x O 0 GRAPHIC LOG MATERIAL DESCRIPTION SAMPLE TYPE NUMBER RECOVERY °/ (ROD) BLOW COUNTS (N VALUE) POCKET PEN. (tsf) 5 j a O MOISTURE CONTENT (%) ATTERBERG LIMITS FINES CONTENT (%) g F- Dg. 7.r 7 PLASTIC LIMIT PLASTICITY INDEX -.ECM? .1/4 ^= a;I. \- Sandy Lean CLAY with Organics (TOPSOIL), brown, moist 2 r ,4, ✓;I/�J/J 'f// Sandy Lean CLAY (GO, brown, moist, medium stiff _ 3 Bottom of test pit a13.0 feet. CLIENT PROJECT ,.,, w HuddlestomBem Engineering & Testing, LLC 640 White Avenue. Unit B Grand iunclion, CO 81501 970-255-8005 970-255.6818 Cheryl Gonzalez PROJECT NAME LOCATION TEST PIT NUMBER TP -3 PAGE 1 OF 1 350 Cedar Hills Rd NUMBER 01313-0001 PROJECT Silt CO DATE EXCAVATION EXCAVATION LOGGED NOTES STARTED BY 11/8/13 COMPLETED 11/8/13 GROUND ELEVATION WATER LEVELS: TIME OF EXCAVATION END OF EXCAVATION EXCAVATION TEST PIT SIZE CONTRACTOR R&S Trucking GROUND dry METHOD Backhoe AT NWB CHECKED BY MAB AT dry AFTER --- la DEPTH (ft) o =O QO K o MATERIAL DESCRIPTION SAMPLE TYPE NUMBER RECOVERY % (RQD) BLOW COUNTS (N VALUE) w 0 U 0.. DRY UNIT WT. (ocf) we �jz mo ATTERBERG LIMITS FINES CONTENT (%) LIQUID LIMIT PLASTIC LIMIT U� Fo n az ^i). ''-4f.1 u...;1%); J !4. /i.sr ?i ii Sandy Lean CLAY with Organics (TOPSOIL), brown, moist 2 // / Sandy Lean CLAY (al), brown, moist, medium stiff 3 Bottom of test pit at 3.0 feet. Huddleston-Beny-Engineering&T«rng,LLC 640 White Avenue, Unit B Grind Junction, CO 81501 970-255-8005 970-255-6818 Gonzalez PROJECT NAME LOCATION TEST PIT NUMBER TP -4 PAGE 1 OF 1 350 Cedar Hills Rd r: --t CLIENT PROJECT �,F• \ 4,; Cheryl NUMBER 01313.0001 PROJECT Sill, CO DATE EXCAVATION EXCAVATION LOGGED NOTES STARTED BY 11/5/13 COMPLETED 11/6/13 GROUND ELEVATION WATER LEVELS: TIME OF EXCAVATION END OF EXCAVATION EXCAVATION TEST PIT SIZE CONTRACTOR R&S Trucking GROUND dry METHOD Backhoe AT NWB CHECKED BY MAB AT dry AFTER --- (LE o 0.0 0 � O MATERIAL DESCRIPTION SAMPLE TYPE NUMBER RECOVERY % (ROD) BLOW COUNTS (N VALUE) POCKET PEN. (tst) t z rc o MOISTURE CONTENT (%) ATTERBERG LIMITS FINES CONTENT (%) g t 2 F F a PLASTICITY INDEX 2.5 �'--`''-t rSandy r • A Sandy Lean CLAY with Organics (TOPSOIL), brown, moist Lean CLAY (off, brown, moist, medium stiff to stiff 5.0 7.5 10.0 Bottom of test pit at 10.0 feet. APPENDIX B Laboratory Testing Results a / Aga970-255-8005 \,..z.---_,/ CLIENT r °O Cheryl Huddleston•Berr Engineering 8: Testing. LLC GRAIN SIZE DISTRIBUTION 640 White Acenae, Unit B Grand Junction, CO 81301 970-255-6813 Gonzalez PROJECT NAME 350 Cedar Hills Rd PROJECT NUMBER 01313-0001 PROJECT LOCATION Sill, CO U.S. SIEVE OPENING 6 4 3 IN NCHES 2 1.5 1 U.S. SIEVE NUMBERS I HYDROMETER 4 112318 3 4 6 810 1416 20 30 40 50 60 100140200 100 95 I 1 I ;_L_�_L� I I l 1 1 90 85 80 75 70 65 F x t6 60 3 55 m reIll 50 z LL 1- 45 z Lu et 40 Ill 0. 35 30 25 20 15 10 5 0 100 10 GRAIN SIZE IN MILLIMETERS 01 0.01 0.001 COBBLES GRAVEL SAND coarse fine coarse medium fine SILT OR CLAY Specimen Identification Classification LL PL PI Cc Cu • TP -1, GB1 1112013 SANDY LEAN CLAY(CL) 28 15 13 Specimen Identification D100 D60 D30 D10 %Gravel %Sand %Silt %Clay • TP -1, GB1 1112013 19 0.104 1.8 45.9 52.3 ATTERBERG LIMITS 013133001350 CEDAR HILLS RD.GP! GIM US LAB.GDT 17/3/13 CLIENT --,,;N ° Cheryl Huddleston -Berry Engineering & Testing. LLC 640 Willie Avenue, Unit B ATTERBERG LIMITS'RESULTS Grind Junction, CO 81501 970-255-8005 970-255.6313 Gonzalez PROJECT NAME 350 Cedar Hills Rd PROJECT NUMBER 01313-0001 PROJECT LOCATION Sill, CO 60 50 CL CH P L A 40 s T I C T 30 Y I N 20 E X 10 • CL -ML ML MH 0 20 40 60 80 100 LIQUID LIMIT Specimen Identification LL PL PI #200 Classification 1 TP -1, GB1 11/2013 28 15 13 52 SANDY LEAN CLAY(CL) �•;- CLIENT n Cheryl Iluddleston-Berry Engineering & Testing. LLC CONSOLIDATION TEST 640 White Avenue, Unit B Grand Junction: CO 31501 970.255.3005 970.255.6318 Gonzalez PROJECT NAME 350 Cedar Hills Rd PROJECT NUMBER 01313-0001 PROJECT LOCATION Silt, CO 0 1 2 • 3 4 5 e 6 �z in 7 8 9 10 11 12 1100 ,000 10,000 STRESS, psf Specimen Identification Classification Td MC% • TP -1 2.0 89 7 t c. Q»GrdJ"ne'ion, \\:._ti970-255-3005 CLIENT PROJECT Huddleston-BerrEngineering & Testing. LLC % "P 640 White Avenue, Unit B CO 31501 970.255.6313 Cheryl Gonzalez MOISTURE PROJECT NAME PROJECT LOCATION -DENSITY RELATIONSHIP 350 Cedar Hills Rd NUMBER 01313-0 01 Sill CO 150 145 140 135 130 125 3 a 120Eu 0 cc 0 115 110 105 100 95 90 0 ! Sample Sample Source Description Test Optimum of Method: Maximum Date: No.: Material: of Material: Dry Water TEST Density Content GRADATION #200 11/6/2013 1 TP -1 SANDY LEAN CLAY(CL) ASTM D698A RESULTS RESULTS 116.0 PCF PASSING) 3/4" 100 \ 13.5 % (% #4 98 52 LL Curves for PL 100% Gravity 2.80 2.70 2.60 PI to: 15 Specific of 13 Saturation Equal \28 \ 5 10 15 20 25 30 WATER CONTENT, % APPENDIX C Percolation Test Data PERCOLATION TESTING Project Name: 350 Cedar Hills Road Location: Silt CO Project No. 01313 - 0001 Test Pit No. TP -2 Date: 11/6/2013 Testing Conducted By: NWB Supervising Engineer: M. Berry Pit Dimensions: Length Water Level Depth: SOIL. PROFILE Depth Desert lion ; Width Not Encountered X ; Depth 3 ft 0-1 ft Sandy Lean CLAY with Organics (TOPSOIL), brown, moist 1-3 ft Sandy Lean CLAY (el), brown, moist, medium stiff Test Number: 1 Top of Hole Depth: 3 ft Diameter of Hole: 4 In. Depth of Hole: 14 in. The (min.) Water Depth (in.) Change (In.) 0 1.375 5 3.25 1.875 10 5.375 2.125 15 6.875 1.5 20 8 1.125 25 9 1 30 9.875 0.875 10.6251; 11.25 `l 0.625 11:625" 0,375 ri 50 12.5 13:375 0.875 60 dry Rate (min/in): 7 Average Percolation Rate (min/in): Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole: Time (min.) Water Depth (in.) Change (in.) Rate (min/in): Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole: Time (min.) Water Depth (in.) Change (in.) Rale (min/in): PERCOLATION TESTING Project Name: 350 Cedar Hills Road Location: Silt CO Project No. 01313 0001 Test Pit No. TP -3 Date: 11/6/2013 Testing Conducted By: NWB Supervising Engineer: M. Berry Pit Dimensions: Length Water Level Depth: SOIL PROFILE Depth Description ; Width Not Encountered X ; Depth 3 fl Remarks 0-1 ft Sandy Lean CLAY with Organics (TOPSOIL), brown, moist '"" Sandstone on North side of pit "` 1-3 ft Sandy Lean CLAY (el), brown, moist, medium stiff 5 2.375 1.25 10 2.75 0.375 15 3.625 0.875 Test Number: 1 Top of Hole Depth: 3 ft Diameter of Hole: 4 in. Depth of Hole: 13 in. Time (min.) Water Depth (in.) Change (in.) 0 1.125 5 2.375 1.25 10 2.75 0.375 15 3.625 0.875 20 4.375 0.75 25 5 0.625 30 5.875 0.875 35 6 0.125 40 7.25 1.25 45 7.5_ 0.25' 50 ,' ' 7.75 0.25 55 = 8.125 0.375 ". 60 8.5 0.375 Rate (min/in): 16 Average Percolation Rate (min/in): Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole: Time (min.) Water Depth (in.) Change (in.) Rate (min/in): Test Number: Top of Hole Depth: Diameter of Hole: Depth of Hole: Time (min.) Water Depth (in.) Change (in.) Rate (min/in): PERCOLATION TESTING Project Name: 350 Cedar Hills Road Location: Silt CO Project No. 01313 - 0001 Test Pit No. TP -4 Date: 11/6/2013 Testing Conducted By: NWB Supervising Engineer: Pit Dimensions: Length ; Width Water Level Depth: . SOIL PROFILE Depth Description Not Encountered X M. Berry Depth 10 ft 0-1 ft Sandy Lean CLAY with Organics (TOPSOIL), brown, moist Change (in.) 1-10 ft Sandy Lean CLAY (el), brown, moist, medium stiff 5 2 1.5 10 2.875 0.875 15 4.25 1.375 Test Number: 1 Top of Hole Depth: 0 ft Diameter of Hole: 4 in. Depth of Hole: 14 In. Time (min.) Water Depth (In.) Change (in.) 0 1.25 5 2.25 1 10 2.625 0.375 15 3.375 0.75 20 4.25 0.875 25 4.75 0.5 30 5.25 0.5 35 5.75 0.5 40 • 6.5 0.75 45 7 .._ ............ 0.5 r. 50 8 60 .'- 8.375 0.375 Rate (minfin): 11 Average Percolation Rate (min/in): Test Number: 2 Top of Hole Depth: 3.5 ft Diameter of Hole: 4 in. Depth of Hole: 14 in. Time (min.) Water Depth (in.) Change (in.) 0 0.5 5 2 1.5 10 2.875 0.875 15 4.25 1.375 20 5.125 0.875 25 5.625 0.5 30 6.75 1.125 35 7.5 0,75 40 8 0.5 45 9 1 50' 9.5 I 0.5 55 10.25 0.75 60 10.5 i 0.25 Rate (min/in):10 Test Number: 3 Top of Hole Depth: 6 ft Diameter of Hole: 4 In. Depth of Hole: 14 in. Time (min.) Water Depth (in.) Change (in.) 0 1.125 5 2.625 1.5 10 3.5 0.875 15 4.625 1.125 20 5.5 0.875 25 6 0.5 30 6.875 0.875 35 7.375 0.5 40 8.375 1 45 9.125 0.75 50 9.625 0.5 55 10' 0.375 60 10.25 0.25 Rate (min/in):13