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Home My WebLink AboutSUB201700090 Certified Engineer's Report 2019-04-194 4 4 G EO-TE RRAI N ORGANIZATION, INC. "YOUR GOALS FOUNDED ON OUR INFORMATION" April 19, 2019 Adelaide Cville, LLC Attn: Kyle Redinger 250 West Main Street Suite 201 Charlottesville, Virginia 22902 RE: California Bearing Ratio Test Results Sparrow Hill Subdivision COT Albemarle County, Virginia GTO Project No.: 19G-282-062 Dear Mr. Redinger: As requested, Geo-Terrain Organization, Inc. (GTO) has obtained representative samples of pavement subgrade soils at locations estimated using the civil engineering consultant produced plans for the Sparrow Hill subdivision at the above referenced project. Samples were obtained where feasible based upon previous investigation and California Bearing Ratio (CBR) tests were performed to verify the required pavement design thicknesses for the proposed development. The testing includes the subdivision roads known as Road A and Road B, all. Design parameters were established based upon the traffic count provided by the civil engineering consultant and laboratory testing. performed on samples of proposed subgrade soils. The following results were obtained by performing CBR testing in general accordance with Virginia Test Method (VTM) 8. The soils on site generally classify as sandy silts, with traces to little gravel and rock fragments, and mica. As tested, these materials have an average soil support values, confirmed by an average CBR value of 6.6. ➢ In paved areas, the soil up to six (6) inches below planned subgrade elevationsfor controlled fills should be compacted to ninety five percent (95%) of its maximum dry density as determined by VTM-1 (AASHTO T-99) Specifications. The final six (6) inches up to subgrade should be compacted to at least one hundred percent (100%) of its maximum dry density. Moisture contents of the subgrade should conform to the moisture specifications set in the VDOT Road and Bridge Specification manual. > Any sidewalk, curb and gutter, and driveway areas should also be treated as above. > The following recommended pavement section is based on the VDOT Vaswani design method for 7 00-A INTERSTATE BUSINESS PARK FREDERICKSBURG, VA Z2405 0 OFFICE: 540-36B-5724 0 FAX: 540-366-5725 Adelaide Cville, LLC Re: California Bearing Ratio Test Results Sparrow Hill Subdivision COT April 19, 2019 Page 2 Secondary Road Pavement, using the above mentioned average CBR value of 6.6. This value should be representative of the soils that may be encountered at pavement subgrades. The resiliency factor for the soil, given by the site location in Albemarle County and soil classifications, is 1.5, and the thickness equivalency factor used is 1.67. The design traffic volume is estimated to be 350 vehicles per day, one direction, for Road A, and 100 vehicle per day, one direction, for Road B. This traffic volume was assumed to contain five (5) percent heavy truck traffic. If plans indicate heavier the pavement sections than the ones listed below, the plan pavement sections should be utilized. Pavement Sections for Road A: Asphaltic Concrete Surface Course, VDOT SM-9.5 3.0 inches Aggregate Subbase Course, VDOT 21A or B 8.0 inches Pavement Sections for Road B: Asphaltic Concrete Surface Course, VDOT SM-9.5 2.0 inches Aggregate Subbase Course, VDOT 21A or B 6.0 inches ➢ Subgrades that have been exposed to weather changes or disturbances should be scarified approximately six (6) inches and recompacted to 100% of Maximum Dry Density immediately prior to the placement of the aggregate base course. The roadway subgrade is also subject to proofroll utilizing a fully loaded tandem axle dump truck or similar pneumatic tire equipment to verify stability prior to the placement of the aggregate base course. Thank you for the opportunity to assist you in this capacity. If you have any questions regarding this letter, please do not hesitate to contact our office. V VVIV VIII IIVGI LIIs111VV1 C:/GTO Documents/GTO Geotechnical 2019/19G-282-062/Sparrow Hill CBR Letter 419-19.doc VIN WIA A-LNnoo �avrwas-Iv - .GYi/Y1R'YIYL�/D71✓".'AVWNYIJONMI':aV/N3.•Zk�9.l'i rJNI 9� z� 'ds rI �7YYKI'XSWAIHS �? A191Au3A0 rolsblra&?s 771 � 0� c �,- ,q and BNV"ld NOL.Lont 1SNOO TlNld 's o �■ dd a .....................�... \ ■�•�Y . •T■■*u. ...u............ .1 1-9 h � irk ,' ..>J� `:'`� ` �� ■ i ■�_-= W ■ I `� t■ i 1` i � I� � ■ �`. i ® � 1, . ■ : •.` ''\ � i� _ ' ■ � it �`�W'CQ a,q1,`1pJ0, C~i. 1:, •-''i _ i t ■ 1 1�Aj _ /%i .� i tf. i l �/i rl 10 Pill coQ �i•^�o� ":sue<;';�� --� r i ¢ � ----- . � '' ' ,'�. r r � r � i ■ �/. .. .v...a��`.'■s.......r�.�...Y:.i/..L1Si... H.i %J.:..r... -...fi.................i -J Virginia Department of Transportation --- Pavement Design Guide cC 1996 (rev2000) Appendix IV Flexible Pavement Design Worksheet for New Subdivision Streets This sheet is intended for use and submission in conjunction with VDOT's Subdivision Street Requirements ' county altCuti4t� Date: /9 Subdivision s u✓!h�✓ f'C� Street Name I Developer �6 i �� 'v, Ye, Phone- Yf)1- YaY./A ADT Projected traffic for the street segment considered, as defined in the Subdivision Street Requirements. CBRD Design CBR = Average of CBRT x 2/3 and modified only as discussed in the Pavement Design Guide. CBRT CBR value of the subgrade sample, taken and tested as specified in the Pavement Design Guide D.hE VDOT District Materials Engineer EPT Equivalent projected traffic HCV Number of Heavy Commercial Vehicles (e.g. trucks, buses, etc., with 2 or more axles and 6 or more tires). %HCV Percentage of the total traffic volume composed of Heavy Commercial Vehicles. RF Resiliency Factor = Relative value of the subgrade soil's ability to withstand repeated loading. SSV Soil support value of subgrade (SSV = CBRD x RF) Dp Thickness index of proposed pavement design computed by the Conventional Pavement Design Method DR Thickness index required, based on Design ADT and SSV, determined by Appendix II. i s:=•-�t ::Ste .- 'w Sceptic. v eteruunesigit ADT- r Eo Determ ine;DesigrisValues=> ,. �'_ CBR;`RF grid-SSV ``,Q -. ADT 45o Sam le DBRT Resihen Factor °/nHCV = 100 x HCV x ADT) f— X '41 ;r' 2 �7•1 F. `� Source Value OT b Table 1 20 x HCV Note: For # 3 a• % A endix I �• Note: For %HCV 0 5%, use ADT %HCV>5%, EPT>ADT tt �f Y 7 DINM a2proved RF #f For rel' P �mary designs, use the lowest RF value in the equation Design ADT Use greater of ADT or EPT 357 CBRD x _ ..:-`.... RF — � �>SSV- : r Step 3 ::P3vernent:Design (Check appropriate box and show proposed pavement design below.) (A) Limited to Design. ADT < 400 - Show pavement material notations and thickness from Appendix IV Tables A and B. — ---------------------------------------------------------- (B) Show pavement section as developed in the Pavement Design Guide. DR _ /6. Z (See Appendix III for material notations and thickness equivalency values (a)). from Appendix II Description of Proposed Pavement Section Material Notation Thickness, h a (a x h) Surface Bass Subbase Dp must equal or exceed the value of DR. Dp = E(a x h) 26 Virginia Department of Transportation -- Pavement Design Guide 0, 1996 (rev2000) Appendix IV Flexible Pavement Design Worksheet for New Subdivision Streets This sheet is intended for use and submission in conjunction with VDOT's Subdivision Street Requirements County �j /<f1 /reveyz(�'�l I Dater.,. Subdivision Street Name - Developer t a % t v, C Phone: ADT Projected traflic for the street segment considered, as defined in the Subdivision Street Requirements. CBRD Design CBR = Average of CBRT x 2/3 and modified only as discussed in the Pavement Design Guide. CBRT CBR value of the subgrade sample, taken and tested as specified in the Pavement Design Guide DME VDOT District Materials Engineer EPT Equivalent projected traffic HCV Number of Heavy Commercial Vehicles (e.g. trucks, buses, etc., with 2 or more axles and 6 or more tires). %HCV Percentage of the total traffic volume composed of Heavy Commercial Vehicles. RF Resiliency Factor = Relative value of the subgrade soil's ability to withstand repeated loading. SSV Soil support value of subgrade (SSV = CBRo x RF) Dp Thickness index of proposed pavement design computed by the Conventional Pavement Design Method DR Thickness index required, based on Design ADT and SSV, determined by Annendix Tr Ste eterminesrgu MTV � '" Ste :2: . sDeterm' ,: •� tns:Deslgn;Vaiues; ti ADT /DO Sample DBRT Resiliency Factor °/aHCV 100 x HCV x ADT) x HCV 0 0 Note: For /oHCV Q 5 /o, use ADT G Note: For %HCV>5%, EPT>ADT # 1 +%• t Sours; Value 6 Table 1or20 A endix I /� D `�%DNM a roved RF For preliminary dsigns, use the lowest RF value in the equation x RF — ':: ;' S `7• . ;; ';: r T Design ADTUse greater of ADT or EPT l boCBRD Steo-3 Pavement:DeSign (Check appropriate box and show proposed pavement design below.) (A) Limited to Design. ADT S 400 - Show pavement material notations and thickness from Appendix IV Tables A and B. - - — ---------•- - ❑ (B) Show pavement section as developed in the Pavement Design Guide. DR = �• 6 (See Appcndix III for material notations and thickness equivalency values (a)). from Appendix 11 Description of Proposed Pavement Section Material Notation Thic Hess, h (a x h) Surface�v,1tC Base ho ("U Subbase Dr must equal or exceed the value of DR. Dp = E(a x h) = 9 3� 26 20 16 40 BEARING RATIO TEST REPORT VTM-008 (2005) 0 0 0 0 0.1 0.2 0.3 0.4 0.5 0.1 0.4 0.2 n Penetration Depth (in.) Elapsed Time (hrs) Molded - - -- - ----- ---- ---- - - --- ---------- Soaked ------ - -- --- --------- ---- ------ — - -- -- CBR � --- ----- ---- --) Linearity Density Percent of Moisture Density Percent of Moisture __ ---- - Correction Surcharge Surcharge Swell (Pcq Max. Dens. (%) (Pcf) Max. Dens. (%) 0.10 in. 0.20 in. (in.) (lbs.) M) 1 O 107.9 100 16.2 107.0 99.2 23.3 7.1 7.0 0.000 10 0.9 20 3❑ ------------------------- ------------------------------ --------- ------------ ------- Material Description Brown sandy Silt, trace mica and gravel Project No: 19G-282-062 Project: Sparrow Hill Subdivision COT Source of Sample: Intersection of Road A and US 250 Sample Number: 1 Depth: subgrade Date: 4-19-19 BEARING RATIO TEST REPORT Geo-Terrain Oraanization USCS Dens. Moisture LL Pi C ML 107.9 16.2 0 0 Test Description/Remarks: Standard Proctor Compaction Figure Moisture -Density Relationship Test 115 I I I —+4 110 ° 105 +! a - - --- - - - ------- -- 100 ! A-F - i - 95-- I - — -- — ---� — --_-- ZAV for I Sp.G. _ 90 { ----- ------ 2.65 3 8 13 18 23 28 33 Water content, % - a— - Rock Corrected - o-- - Uncorrected Test specification: ASTM D 698-91 Procedure A Standard ASTM D4718-15 Oversize Corr. Applied to Each Test Point Elev/ Depth Classification Nat. Moist. Sp.G. LL PI % > #4 % < No.200 USCS AASHTO subgrade NIL A-4(0) 16.6 2.65 0 0 3.7 62.8 ROCK CORRECTED TEST RESULTS UNCORRECTED MATERIAL DESCRIPTION Maximum dry density = 107.9 pef Optimum moisture = 16.2 % 106.4 pcf 16.8 % Brown sandy Silt, trace mica and gravel Project No. 19G-282- Client: Adelaide Cville, LLC Project: Sparrow Hill Subdivision COT o Source: Intersection of Road A and US 250 Sample No.: 1 Remarks: Figure Geo-Terrain Organization 100 90 80 70 0' W 60 Z U- Z 50 W U G: a ao 30 20 10 0 Particle Size Distribution Report . VI\/11IV VILG- % +3„ °k Gravel % Sand Coarse Fine Coarse Medium 0.0 0.0 3.7 1 4.2 15.2 SIEVE SIZE PERCENT FINER SPEC." PERCENT PASS? (X=NO) 375 100.0 #4 96.3 #10 92.1 #40 76.9 #200 62.8 % Fines ---------- --------------- - ---- Fine Silt 14.1 62.8 Material Description Brown sand; Silt, trace mica and gravel Atterberg Limits PL= 0 LL= 0 Pl= 0 Coefficients D90= 1.5092 D85= 0.9034 D60= D50= D30= D15= D10= Cu= Cc= Classification USCS= NIL AASHTO= A-4(0) Remarks - (no specification provided) Source of Sample: Intersection of Road A and US 250 Depth: subgrade Sample Number: 1 Date: 4-19-19 Client: Adelaide Cville, LLC Project: Sparrow Hill Subdivision COT Geo-Terrain Organization Project No: 19G-282-062 Figure BEARING RATIO TEST REPORT VTM-008 (2005) 200 2 160 1.6 a .r U 120 1.2 c n .y o _ iZ' d O W c0 .�. 80 0.8 m c a 40 0.4 0 0 v, 0.2 0.3 0.4 48 72 96 0 0.1 0.5 0 24 Penetration Depth (in.) Elapsed Time (hrs) Molded - -- - - - - -- -- - Soaked -- -- --- - - - - ----- -- -- -- --- CBR - -- ----f - 1 -- - Linearity Surcharge Max. Density Percent of Moisture Density Percent of Moisture 0.10 In. 0.20 in. Correction (lbs•) Swell (pcf) Max. Dens. (%) (pcf) Max. Dens. 1%) (in.) (%1 1 O - 106.2 99.8 15.1 - - -- -- ------- 105.0 98.7 1 23.1 6.4 6.3 0.000 10 1.2 2 A 3 0 , - -- -------- ------ -- Material Description USCS Max. Dens. Optimum Moisture LL PI C Brown sandy Silt, trace gravel, mica, and clay ML 106.4 15.0 39 3 Project NO: 19G-282-062 Test Description/Remarks: Project: Sparrow Hill Subdivision COT Standard Proctor Compaction Source of Sample: In front of Lots 30 and 31 on Road A Sample Number: 2 Depth: subgrade Date: 4-19-19 BEARING RATIO TEST REPORT Geo-Terrain Organization Figure Moisture -Density Relationship Test 115 i 110 105 U CL - - i o 100 � i 00 95 I 90 -- i i j -- _ I ----- -- I --_-_-- --- ZAV for Sp.G. _ 2.65 2 7 12 17 22 27 32 Water content, % —f— - Rock Corrected --p— - Uncorrected Test specification: ASTM D 698-91 Procedure A Standard ASTM D4718-15 Oversize Corr. Applied to Each Test Point Elev/ Depth Classification Nat. Moist. Sp.G. LL PI % > #4 % < No.200 USCS AASHTO subgrade ML A-4(3) 17.9 2.65 39 3 1.1 70.1 ROCK CORRECTED TEST RESULTS UNCORRECTED MATERIAL DESCRIPTION Maximum dry density = 106.4 pcf Optimum moisture = 15.0 % 105.9 pcf 15.2 % Brown sandy Silt, trace gravel, mica, and clay Project No. 19G-282- Client: Adelaide Cville, LLC Project: Sparrow Hill Subdivision COT o Source: In front of Lots 30 and 31 on Road A Sample No.: 2 Remarks: Figure Geo-Terrain Organization 11 MINE llimillillilmillilill 11111I1M11111111M 11 GRAIN SIZE - % +3 % Gravel % Sand _ Coarse Fine Coarse Medium 0.0 0.0 1.1 7.6 6.7 SIEVE SIZE PERCENT FINER SPEC.' PERCENT PASS? (X=NO) 375 100.0 #4 98.9 #10 91.3 #40 84.6 #200 70.1 °k Fines ----------- -------------------------------- Fine Silt _ 14.5 70.1 Material Description Brown sandy Silt, trace gravel, mica, and clay Atterberg Limits PL= 36 LL= 39 PI= 3 Coefficients D90= 1.6783 D85= 0.4642 D60= D50= D30= D15= D10= CU= Cc= Classification USCS= ML AASHTO= A-4(3) Remarks (no specification provided) Source of Sample: In front of Lots 30 and 31 on Road A Depth: subgrade Sample Number: 2 Date: 4-19-19 Client: Adelaide Cville, LLC Geo-Terrain Organization Project: Sparrow Hill Subdivision COT Project No: 19G-282-062 Figure BEARING RATIO TEST REPORT VTM-008 (2005) 200 1 160 0.8 C. v 120 0.6 C Uf � d O 80 0.4 d C m a 40 0.2 0 0 V I I I I 0.2 0.3 0.4 48 0 0.1 0.5 0 24 72 96 Penetration Depth (in.) Elapsed Time (hrs) Molded _ _ _ Soaked CBR ------- ______ Linearity Surcharge Max. Density Percent of Moisture Density Percent of Moisture in. 0.20 in. Correction (ibs.) Swell (pcf) Max. Dens. M (pcf) Max. Dens. M0.10 (in) M 1 O 110.8 100.1 15.5 109.9 99.2 21.2 8.1 7.6 0.000 10 0.9 3a Material Description USCS Max. Dens. optimum Moisture LL PI Gray and Brown silty fine to coarse grained Sand, trace gravel, mica, and (120 M clay SM 110.7 15.4 33 6 Project No: 19G-282-062 Test Description/Remarks: Project: Sparrow Hill Subdivision COT Standard Proctor Compaction Source of Sample: Intersection of Road A and Road B Sample Number: 3 Depth: subgrade Date: 4-19-19 BEARING RATIO TEST REPORT Geo-Terrain Organization Figure Moisture -Density Relationship Test 118 1 113 777-1 10 N 103 98 ZAV for Sp.G. 93 2.65 3 8 13 18 23 28 33 Water content, % - Rock Corrected Uncorrected Test specification: ASTM D 698-91 Procedure A Standard ASTM D4718-15 Oversize Corr. Applied to Each Test Point Elev/ Depth Classification Nat. Moist. Sp.G. LL PI % > #4 % < No.200 USCS AASHTO subgrade Sm A-4(1) 11.2 2.65 33 6 4.9 49.6 ROCK CORRECTED TEST RESULTS UNCORRECTED MATERIAL DESCRIPTION Maximum dry density = 110.7 pcf Optimum moisture = 15.4 % 108.8 pcf 16.0% Gray and Brown silty fine to coarse grained Sand, trace gravel, mica, and clay Project No. 19G-282- Client: Adelaide Cville, LLC Project: Sparrow Hill Subdivision COT o Source: Intersection of Road A and Road B Sample No.: 3 Remarks: Figure Geo-Terrain Organization Particle Size Distribution Report 100 90 80 70 W W 60 Z LL Z 50 W U W d 40 30 20 10 0 L7RMIIV JILC - 111111. +3" % Gravel % Sand % Fines -- ----- - --- --- - --- - - - --- ----- --- - - - --- - -- - - --- —----------- Coarse Fine Coarse Medium Fine Silt Clay 0.0 0.0 4.9 6.3 6.2 33.0 49.6 SIEVE SIZE PERCENT FINER SPEC.' PERCENT PASS? (X=NO) .375 100.0 #4 95.1 #10 88.8 #40 82.6 #200 49.6 Material Description Gray and Brown silty fine to coarse grained Sand, trace gravel, mica, and clay Atterbera Limits PL= 27 LL= 33 P1= 6 Coefficients D90= 2.4529 D85= 0.5872 D60= 0.1172 D50= 0.0763 D30= D15= D10= CU= Cc= Classification USCS= SM AASHTO= A-4(1) (no specification provided) Source of Sample: Intersection of Road A and Road B Depth: subgrade Sample Number: 3 Remarks Date: 4-19-19 Client: Adelaide Cville, LLC Geo-Terrain Organization Project: Sparrow Hill Subdivision COT Project No: 19G-282-062 Figure_ 200 160 40 BEARING RATIO TEST REPORT VTM-008 (2005) 2 i l 0.8 0.4 1 48 Penetration Depth (in.) Elapsed Time (hrs) Molded Soaked - - -- ----------- --- — ----- Density Percent of Moisture (Pcf) Max. Dens. (%) CBR (%) -- - --- - - ----- 0.10 in. 0.20 in. Linearity Correction (in.) Surcharge (ibs.) Max. Swell (%) ----- - Density Percent of Moisture (Pcf) Max. Dens. (%) 1 O 95.3 100.3 22.4 93.8 98.8 28.3 4.7 4.5 0.000 10 1.6 2A 3❑ Material Description Reddish Brown sandy elastic Silt, trace gravel Project No: 19G-282-062 Project: Sparrow Hill Subdivision COT Source of Sample: Near Cul-de-Sac of Road B Sample Number: 4 Depth: subgrade Date: 4-19-19 BEARING RATIO TEST REPORT Geo-Terrain Organization USCS Dens. Moisture LL PI C MH 95.0 22.3 54 10 Test Description/Remarks: Standard Proctor Compaction Figure w Moisture -Density Relationship Test 103 98 i 93 I I I � .T C 88 i ZAV for 83 78 5 10 15 20 25 30 35 Water content, % - Rock Corrected —0— - Uncorrected Test specification: ASTM D 698-91 Procedure A Standard ASTM D4718-15 Oversize Corr. Applied to Each Test Point Elev/ Depth Classification Nat. Moist. Sp.G. LL PI % > #4 % < No.200 USCS AASHTO subgrade MH A-5(15) 23.2 2.65 54 10 0.5 90.0 ROCK CORRECTED TEST RESULTS UNCORRECTED MATERIAL DESCRIPTION Maximum dry density = 95.0 pcf Optimum moisture = 22.3 % 94.8 pef 22.4 % Reddish Brown sandy elastic Silt, trace gravel Project No. 19G-282- Client: Adelaide Cville, LLC Project: Sparrow Hill Subdivision COT o Source of Sample: Near Cui-de-Sac of Road B Sample Number: 4 Remarks: Figure Geo-Terrain Organization 100 90 80 70 60 50 40 30 20 10 0 Particle Size Distribution Report VI\/"�IIV VILG - % +3„ °k Gravel % Sand Coarse Fine Coarse Medium_ 0.0 0.0 0.5 0.6 0.8 SIEVE SIZE PERCENT FINER SPEC.' PERCENT PASS? (X=NO) .375 100.0 #4 99.5 #10 98.9 #40 98.1 4200 90.0 Fine Silt 8.1 Fines 90.0 Material Description Reddish Brown sandy elastic Silt, trace gavel Atterberg Limits PL= 44 LL= 54 Pl= 10 Coefficients D90= D85= D60= D50= D30= D15= D10= Cu= Cc= Classification USCS= MH AASHTO= A-5(15) Remarks (no specification provided) Source of Sample: Near Cul-de-Sac of Road B Depth: subgrade Sample Number: 4 Date: 4-19-19 FClient: Adelaide Cville, LLC Geo-Terrain Organization Project: Sparrow Hill Subdivision COT Project No: 19G-282-062 Figure