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HomeMy WebLinkAbout10.01 Subgrade Investigation and Pavement Design on-site roadsSUBGRADE INVESTIGATION AND PAVEMENT DESIGN PHASE I ROADS SPRING VALLEY RANCH GARFIELD COUNTY, COLORADO CTL/THOMPSON, INC. CONSULTING ENGINEERS SUBGRADE INVESTIGATION AND PAVEMENT DESIGN PHASE IROADS SPRING VALLEY RANCH GARFIELD COUNTY, COLORADO Prepared For: SPRING VALLEY DEVELOPMENT, INC. 415 East Hyman Ave., Suite 101 Aspen, CO 81611 Attention: Mr. Cam Kicklighter Job No. GS -3347 July 26, 2001 CTL/TH®MPSON, INC. CONSULTING ENGINEERS 234 CENTER DRIVE s GLENWOOD SPRINGS, COLORADO 81601 ■ (970) 945-2809 TABLE OF CONTENTS SCOPE 1 FIELD AND LABORATORY INVESTIGATION 1 PAVEMENT DESIGN PAVEMENT SELECTION 3 MATERIALS AND CONSTRUCTION 4 MAINTENANCE 4 LIMITATIONS 4 FIGURE 1 - APPROXIMATE LOCATIONS OF EXPLORATORY BORINGS FIGURES 2 THROUGH 7 - SUMMARY LOGS OF EXPLORATORY BORINGS APPENDIX A - LABORATORY TEST RESULTS APPENDIX B - PAVEMENT DESIGN CALCULATIONS APPENDIX C - GUIDELINE SITE GRADING SPECIFICATIONS APPENDIX D - MATERIAL AND CONSTRUCTION CHECKLIST APPENDIX E -GUIDELINE MAINTENANCE RECOMMENDATIONS 2 SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLIT JOB NO. GS -3347 SCOPE This report presents the results of our subgrade investigation and pavement design for Phase I roads at Spring Valley Ranch in Garfield County, Colorado. The purpose of this investigation was to determine the type and support characteristics of subgrade soils present below the proposed roads and provide design pavement alternatives and construction guidelines. The scope of our investigation was described in our Proposal No. GS -01-152 The report includes a description of the subgrade soils found in our exploratory borings, laboratory test results, alternative pavement sections, and construction and materials guidelines. The pavement alternatives presented were based upon laboratory test results and the AASHTO design methods. FIELD AND LABORATORY INVESTIGATION The total length of paved roads in Phase I will be approximately 45,000 feet. At this writing, roads have been "roughed in" to near subgrade elevations along approximately 31,000 lineal feet of the proposed road alignments. Our field investigation consisted of 100 borings spaced about 300 feet apart at the approximate locations shown on Figure 1. Soils found in our borings generally consisted of soft to stiff, moist to very moist, sandy to silty clay and clay -silt and medium dense to dense, moist, silty to clayey gravel with scattered cobble. Free ground water was not encountered in the exploratory borings to depths of 5 to 15 feet beneath the ground surface. Figures 2 through 7 show logs of soils found in our borings. Classifications and engineering properties of samples of the soils encountered in our borings are summarized on Table A -I. The laboratory testing program was designed to provide index properties of the soils sampled and subgrade support values for those soil types which influence SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLTf JOB NO. GS -3347 1 the pavement design. In general, two types of subgrade soils are present below roads in Phase I. Hveem Stabilometer tests were performed on composite samples of each subgrade soil type (Group I and Group 2) to determine a design support value ("R" value). Test results are presented in Appendix A. Group I soils were granular and testing indicated an "R" value of 15. Group 2 soils were cohesive and testing indicated an "R" value of 8. The Effective Resilient Modulus (based on the CDOT modified design criteria) was calculated to be 4,198 psi for Group I soils and 3,334 psi for Group II soils. PAVEMENT DESIGN We used the (ESAL) application twenty-year design design alternatives AASHTO design method. The design equivalent single -axle load used for design was 21,900. The ESAL calculations are for a life. Design calculations are presented in Appendix B. Pavement are presented on TABLE A below. TABLE A PAVEMENT DESIGN ALTERNATIVES Group 1 5.0" AC 3.0"AC+5.0"ABC + Fabric 3.0" AC + 7.0"ABC Group 2 6.0" AC 3.0" AC + 7.0"ABC + Fabric 3.0" AC + 9.0"ABC or 4.0" AC + 6.0"ABC SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS -3347 2 anticipated traffic Toads change considerably, we should be contacted to review the recommendations. We believe the geotechnical services for this project were performed in a manner consistent with that level of care and skill ordinarily exercised by members of the profession currently practicing under similar conditions in the locality of the project. No other warranty, express or implied, is made. If we can be of further service in discussing the contents of this report, or in the analyses of the proposed pavement systems from a geotechnical point of view, please call. SPRING VALLEY DEVELOPMENT, INC. PHASE ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS -3347 5 PAVEMENT SELECTION We have provided three pavement design alternatives including full -depth asphalt concrete, asphalt concrete over aggregate base course over geotextile fabric, and asphalt concrete over aggregate base course without fabric. Our experience indicates each of the three recommended alternatives can perform adequately at this site. In our opinion, the alternative using aggregate base course without fabric is likely more susceptible to reduction in subgrade soil support from wetting and premature failure comparative to the other two alternatives. If aggregate base course is used, woven geotextile fabric placed on the subgrade soil will reduce migration of base course material into the clayey subgrade soils and resulting loss of support. A full -depth asphalt concrete section would be least susceptible to loss of subgrade soil support related to moisture infiltration and is the preferable option from a geotechnical viewpoint. The majority of the road alignments were near subgrade elevations at this writing. Grading to achieve subgrade elevations is required for some sections of road. Appendix C provides guideline site grading specifications for the roads. Subgrade should be moisture conditioned to within 2 percent of optimum moisture content and compacted to at least 95 percent standard Proctor dry density (ASTM D 698). The moisture treated subgrade may produce isolated areas of yielding subgrade. Compaction of the first lift of the asphalt section may be difficult. As with any low traffic volume pavement, embrittlement of asphalt and moisture infiltration into the subgrade soils will be the primary causes of distress. Care must be taken to provide proper maintenance throughout the life of the pavement to ensure a 20 -year service life. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTUT JOB NO. GS -3347 3 1 MATERIALS AND CONSTRUCTION The performance of a pavement system is determined by the quality of the paving materials and construction practices. A material and construction checklist is presented in Appendix D. During construction, careful attention should be paid to the following details: • Placement and compaction of trench backfill. ■ Compaction at curblines and around manholes and water valves. • Excavation of completed pavements for utility construction and repair. • Design slopes of the adjacent ground and pavement to rapidly remove water from the pavement surface. MAINTENANCE We recommend a preventive maintenance program be developed and followed for all pavement systems to assure the designlife can be realized._ Choosing to defer maintenance usually results in accelerated deterioration leadingto. higher, future maintenance costs. A recommended maintenanceprogram:is: outlined in Appendix E. LIMITATIONS The pavement and construction recommendations are based upon our field observations and laboratory testing and design criteria required by the AASHTO design methods. The design procedures were formulated to provide sections with adequate structural strength. Routine maintenance, such as sealing and repair of cracks, is necessary to achieve the long-term life of a pavement system. If the design recommendations and construction guidelines cannot be followed, or SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS -3347. 4 0 0 c s 0 0 0 O c t 0 0 0 NMI Job No. GS -3347 0 5 10 15 0 5 10 15 S-1 S-11 46 S-2 1 / • / / / / / / • / / / / / / / / S-12 1.4 S-3 S-13 S-4 S-14 �.Q 411. S-5 to 44. S-15 S-6 S-16 150 S-7 1 S-17 SUMMARY LOGS OF EXPLORATORY BORINGS S-8 S-18 I or • / / / / • / / / / / S-9 / / / / / / / / / / / / S-19 e•� S-10 S-20 0 5 10 15 — 0 5 10 15 0 0 v s 0 0 }eeJ ui 44ded Fig. 2 Depth In Feet MEIN • Job No. GS -3347 0 5 10 S-21 3.3 l�s S-22 5-23 / • / / / / / / • / S-24 // / / / / / / / / / 5-25 5-26 S-27 / , / / / / / / / / / / / S-28 5-29 33 444 'at? S-30 0 5 10 15 15 0 5 10 15 S-31 S-32 Pio to CO, S-33 44 re0 44 1)0 rtsCt 44 �►d 5-34 otel ,'tom S-35 S-36 5-37 / / / / / / / / / / / /. SUMMARY LOGS OF EXPLORATORY BORINGS 5-38 S-39 S-40 / / II II 0 5 10 15 v m ✓ F m m 40ej ul y{ded Fig. 3 0 0 • IAN c _ 0 0 c L 0. 0 0 • 11 PENN EOM Mel MOM 0 5 10 S-41 S-42 htt is i S-43 S-44 5-45 S-46 S-47 / i / • / / / / / / / / S-48 S-49 3-50 itto Ike 0 5 10 15 15 0 5 S-51 S-52 S-53 iro is S-54 S-55 t S-56 / / / 44 / / / S-57 / / / • / / • / / / S-58 / � / • / / • / / / / / S-59 S-60 coo a 0 5 10 10 15 SUMMARY LOGS OF EXPLORATORY BORINGS 15 11 EMI 0 0 -o 1 0 0 poi ul y;dea Job No. GS -3347 Fig. 4 c L 0 0 0 0 m C .c 0 0 m 0 — 0 5 10 S-61 S-62 S-63 S-64 / / • / / • / / S-65 S-66 / • / / • / / / / / S-67 // / / / / / / / / S-68 / / • / / • / / / / / S-69 / / / / / / / / / / / • / S-70 / / / / / • / / / / / • / 0 5 10 15 15 0 5 10 S-71 / • / / • / / • / • / S-72 / / / / / / / S-73 / / / / / / / / / / / S-74 / / / / / / / / / S-75 S-76 S-77 S-78 S-79 S-80 / / / / / • / / / s / • / 0 5 10 15 15 MOM ISM 0 0 v 0 0 0 0 7 m 0 SUMMARY LOGS OF EXPLORATORY BORINGS Job No. GS -3347 Fig. 5 Depth In Feet m 1 C 0 5-81 S-82 S-83 S-84 S-85 S-86 S-87 S-88 S-89 S-90 0 / / ill — — / • / / • / rQlr4-4 y, rO,yrll�rl1Q-rl, •S) .04 ,r / • / / • // / / / 11 / • / — / • / ylQ4rl!j r,l!414 AQ— — 5/ / 6 / / / / S. 5 10 10 — 15 Job No. GS -3347 0 5 10 S-91 S-92 S-93 S-94 / / / • / / / / S-95 S-96 S-97 S-98 S-99 rid S-100 15 0 5 10 15 15 SUMMARY LOGS OF EXPLORATORY BORINGS Fig. 6 LEGEND: © Clay, sandy, silty to clay—silt, soft to stiff, moist to very moist, brown, tan. (CL, CH, CL—ML or ML) I]] NOTES: Gravel, silty to clayey, scattered cobble, medium dense to dense, moist, brown or tan. (GM, GC) Indicates bulk sample taken from auger cuttings. 1. Exploratory borings were drilled on May 21, 22 and 24, 2001 with 4—inch diameter, continuous flight auger and an all—terrain drill rig. 2. Locations of exploratory borings are approximate. 3. No free ground water was found in our exploratory borings at the time of drilling. 4. These exploratory borings are subject to the explanations, limitations and conclusions as contained in this report. SUMMARY LOGS OF EXPLORATORY BORINGS Job No. GS -3347 Fig. 7 APPENDIX A LABORATORY TEST RESULTS SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLJT JOB NO. G8-3347 EXUDATION PRESSURE (PSI) 900 800 700 600 500 400 300 200 100 0 ; • L _J - - Group Number 1 AASHTO Classification Liquid Limit • ; Plasticity Index - - Design R -Value 15 10 ' R" VALUE Job No. GS -3347 20 30 40 50 60 70 80 90 100 Hveem Stabilometer Test Results 110 Fig. A-1 EXUDATION PRESSURE (PSI) 900 800 700 600 500 400 300 200 100 0 ' Group Number 2 AASHTO Classification Liquid Limit Plasticity Index Design R -Value 8 . _ N_ _ _ _ _ _ _ 10 ' R" VALUE Job No. GS -3347 20 30 40 50 60 70 80 90 100 Hveerrm Stabilometer Test Results 110 Fig. A-2 JOB NO. GS -3347 Description CLAY, SANDY GRAVEL, CLAYEY GRAVEL, CLAYEY } 0 0 Z cn U 1GRAVEL, CLAYEY 1 GRAVEL, SILTY CLAY, SANDY GRAVEL, CLAYEY IGRAVEL, CLAYEY GRAVEL, SILTY GRAVEL, CLAYEY GRAVEL, SILTY GRAVEL, SILTY } 0 Z Q co U GRAVEL, SILTY CLAY, SANDY GRAVEL, SILTY GRAVEL, SILTY GRAVEL, CLAYEY } 0 Z Q cs) U CLAY, SANDY CLAY, SANDY >- 2 Z Q co Q U GRAVEL, CLAYEY GRAVEL, CLAYEY CLAY, SANDY CLAY, SANDY S I LT, C FAYEY GRAVEL, CLAYEY GRAVEL, CLAYEY CLAY, SANDY N N co O 0 0 CO w C IJw N _ O.- 2 i 0 o a 30" d (q N LClassification 1 D N -c J 000 O O CL GC GM CL 0 CD GC 1 co0CDcooco V 22 _M CL 1 2 CDCDco 20 CL JJ UUU J GC 0 0 CL CL J MC7 U GC CL AASHTO CO a¢Q<<<<<<QQaQaQQ¢Q¢a¢a¢a¢QQaaa¢ (R <r (O(ONOO O 1" N V V NM(O(O(OV O(O (2 99 Q co o_ x 7 O 0 C rr 0 u7 CO O V d'r 000 O 00 CO r- r- V r CO v- CO q'I)-r Atterberg Limits a U N_ N'O o CO C - 0 O07O rrrrr V (0 r r N.--. rr CO N N O r r' L 35 p V CO Mr V 20 1 O r Or 00 24 CON rNr V Nrrr r N r- CV o i. O' 'Eo J MMMMMMM Cr)O CF') 36 34 W M U7 CV MY CV 7 Cr)M CO Cr)O 26 ((0 40 CO 38 34 38 37 N V O O C p N O m N N co O 0_0_Z� r Cg NI M r- N co UO 47 23 co (O to V O CO CL7(O CO r CO M N M N C9 N CO u] r COO N M CO CO LO CO OO N 'Cr 1.0 P7 r- OOOO CQ UO V V CO TO >. n G N m 0 m Q Z 0 (` J ^ 3 O E. 0 co2U N V O r N N R C' O r CO• Un CO N- N N• 7.0 It u7 co co 20.7 r Oi rrrr c0 cr O O (O 8.5 1 23.8 N n co V c- V rr r CO r ._ r rrrrr r CO V CO M N (JO r CO M ` N N 2 Z 0 N r r r r r N r r r r r r N r 2 1 r r r r r N N r r N r r r r r L .-. gm N p:- 9 O t0 .r O r u? CD u79 C7 47 C7 0 u7 0 0-5 CO 0 CO 0 UO 0 u? 0 u? O 0-5 0-5 0-5 u7 O 0-5 T- Lc? 0 9 0 u7 CD U�J9 0 0 0-5 u7 9 UO O CD CD 0-5 u? O tO o To_ n Z 0 fQ N 0 W CO 0 N 0 N u4 r 0 0 to (n m 0 fn r N CO CA 10 fA r CA m C7 N (A S23 u� N N S27 rn N N 531 0 (`1 N S35 S37 w co CA V' CO S43 S45 r CI 'Q V' LO CO CO CO CO U) CO cal CO N r N CD JOB NO. GS -3347 Description CLAY, SANDY GRAVEL, CLAYEY GRAVEL, CLAYEY J U CLAY, SANDY CLAY, SANDY CLAY, SANDY CLAY, SANDY CLAY, SANDY CLAY, SANDY GRAVEL, SILTY 0 Q co J U GRAVEL, CLAYEY GRAVEL, CLAYEY 0 Q U GRAVEL, CLAYEY GRAVEL, CLAYEY GRAVEL, CLAYEY CLAY, SANDY GRAVEL, CLAYEY I GRAVEL, CLAYEY GRAVEL, CLAYEY ` N N N A N iii 7 w o v C ©To 0) - O. L- 0) 0 a 30 0_ (0 N Classification Unified J 0 U (9 GC J J U J U J U J J J U U U 2 (9 CL GC U (D J U GC U (3 U (D J U U (D U (D U CO AASHTO INNVrn(O IT_ QQQQQ • CO co cc) QQQQQ CQ QQ ,r Q' Qr (Prn r t; CON (9QQ a X oa 0 r 00 corn rn03 rr r 2 J CO CV CO 0r U) 0)(O CO0 Atterberg Limits a .N ao N C a N0 22 (O({( r N(0 r r r r v r 04 CO r W 25 Cr) r CV 0 _ J cr J o J (•) V 22 I N V N N 0si CO 35 35 CO N V' CO CO O V N CO 0 V 38 1 34 CO N x N 1- 45 43 V CO CD N tm CO N (5j V) N> N N O a4 en 0_ 0_ z (B N Nr40 I- V r U') 67 70 84 76 87 of (O N N- N co CO 51 o) NN co (O V' CO CO U) V V N- CV To ' a.,'(') o 0 N • Z 0 N O N,(O((,,(.)c0(-N- as'5 R 15 o z70 .^-r-� 17.7 6.5 d'NON r(r V CV er-N- (NI 3.6 o - O Z N r r r r r r N N N r r r r r r r r r r r r L r' N N 0 0 t - 0-5 U)(() O 0 U) O 0-5 U) N 0 0 NU) NU) 0 0 0 0 14? 0 0 u? 0 0-5 U) 0 u7 0 0-5 U)U)U) 0 0 0 0-5 U) o- 6 E z co (A (n M43 (A to CDn 18 T13 CO(A 0 M u) r (0 (n (0 379 (0 M CO(0 Lgol 0 I S87 S88 O (0 N (A I Ss4 N N CO N cD N APPENDIX B PAVEMENT DESIGN CALCULATIONS SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLJT JOB NO. GS -3347 o 0 v ry x\ 1111 1 Nut tit I ( Ise/ ) W gavo A 132IA.4S 32f MOS 0390V0iJ 3A1103d.i3 N STRUCTURE NUMBER, SN ( SNOI1111^/ ) BIM 'SNOIIVOIIddY OVO1 3lXV 319NIS 1N31VAIf103 dP1-13I 1V101 021Vw11S] 0 0 o ' 0 `? of ;4 N0j, i.3 frON 'l a 11 0 cTi a 0 0 • 0 0 0 1 1 1 1 1 1 1 1 11 (x)S 'A 11119 V I13tl Interior Streets 0_ O r O O 1 r O h N DESIGN CHART FOR FLEXIBLE PAVEMENT Job No. GS -3347 IL.... . Ism 311_171 ‘ g Ss ..N . o 0 v ry x\ 1111 1 Nut tit I ( Ise/ ) W gavo A 132IA.4S 32f MOS 0390V0iJ 3A1103d.i3 N STRUCTURE NUMBER, SN ( SNOI1111^/ ) BIM 'SNOIIVOIIddY OVO1 3lXV 319NIS 1N31VAIf103 dP1-13I 1V101 021Vw11S] 0 0 o ' 0 `? of ;4 N0j, i.3 frON 'l a 11 0 cTi a 0 0 • 0 0 0 1 1 1 1 1 1 1 1 11 (x)S 'A 11119 V I13tl Interior Streets 0_ O r O O 1 r O h N DESIGN CHART FOR FLEXIBLE PAVEMENT Job No. GS -3347 DESIGN CALCULATIONS (GROUP 1 SOILS) DESIGN DATA Equivalent Single -axle Load (ESAL) = 21,900 Hveem Stabilometer (R -Value) = 15 (from Fig. A-1 ) Structural Number (SN) = 2A (from Fig. A-3 ) DESIGN EQUATION SN = C1D1 + C2D2 C, = 0.40 - Strength Coefficient - Asphalt Concrete C2 = 0.12 - Strength Coefficient - Aggregate Base Course D, - Depth of Asphalt Concrete (inches) D2 - Depth of Aggregate Base Course (inches) FOR ASPHALT CONCRETE SECTION: D, = ( 2.1 )/0.40 = 5.3 inches of Asphalt Concrete FOR ASPHALT + AGGREGATE BASE COURSE SECTION: D2 = (( 2.1 ) - (3.0)(0.40))!0.12 = 7.5 inches of Aggregate Base Course RECOMMENDED SECTIONS: E 1. 5.0 inches of Asphalt Concrete, or 2. 3.0 inches Asphalt Concrete + 7.0 inches Aggregate Base Course, or 3. 3.0 inches Asphalt Concrete + 5.0 inches Aggregate Base Course + Fabric. SPRING VALLEY PUD PHASE 1 ROADS CTL/T JOB NO. GS -3347 B-2 APPENDIX C GUIDELINE SITE GRADING SPECIFICATION SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS -3347 GUIDELINE SITE GRADING SPECIFICATIONS 1. DESCRIPTION This item shall consist of the excavation, transportation, placement and compaction of materials from locations indicated on the plans, or staked by the Engineer, as necessary to achieve subgrade elevations for areas which will support pavements. 2. GENERAL The Soils Engineer shall be the Owner's representative. The Soils Engineer shall approve fill materials, method of placement, moisture contents and percent compaction, and shall give written approval of the completed fill. 3. CLEARING JOB SITE The Contractor shall remove all existing deleterious material before excavation or fill placement is begun. The Contractor shall dispose of the cleared material to provide the Owner with a clean, neat appearing job site. Cleared material shall not be placed in areas to receive fill or where the material will support structures of any kind. 4. SCARIFYING AREA TO BE FILLED All topsoil and vegetable matter shall be removed from the ground surface upon which fill is to be placed. The surface shall then be plowed or scarified to a depth of at least 8 inches until the surface is free from ruts, hummocks, rocks larger than 8 inches in diameter or other uneven features, which would prevent uniform compaction by the equipment to be used. 5. COMPACTING AREA TO BE FILLED After the subgrade surface for the fill has been cleared and scarified, it shall be brought to the proper moisture content (2 percent below to 2 percent above optimum moisture content) and compacted to at least 95 percent of maximum density as determined in accordance with ASTM D 698. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTUT JOB NO. GS -3347 C-1 6. FILL MATERIALS Fill soils shall be free from vegetation, organics, or other deleterious substances, and shall not contain rocks having a diameter greater than four inches. Fill materials shall be obtained from cut areas shown on the plans or staked in the field by the Engineer or imported to the site. On-site materials classifying as CL, SC, SM, SW, SP, GP, GC and GM are acceptable as defined by ASTM D 2487-83. Imported fill soils should be approved by the soils engineer prior to hauling to the site. 7. MOISTURE CONTENT Fill material shall be moisture treated to within limits of optimum moisture content specified in MOISTURE CONTENT AND DENSITY CRITERIA. Sufficient laboratory compaction tests shall be made to determine the optimum moisture content for the various structural fill soils and other type fill soils. The Contractor will be required to add moisture to the fill soil prior to compaction of fill lifts. The Contractor may be required to rake or disc the fill soils to provide uniform moisture content through the soils. Should too much water be added to any part of the fill, such that the material is too wet to permit the desired compaction from being obtained, rolling and all work on that section of the fill shall be delayed until the material has been allowed to dry to the required moisture content. The Contractor will be permitted to rework wet material in an approved manner to hasten its drying. 8. COMPACTION OF FILL AREAS Selected fill material shall be placed and mixed in evenly spread layers. After each fill layer has been placed, it shall be uniformly compacted to not less than the specified percentage of maximum density given in MOISTURE CONTENT AND DENSITY CRITERIA. Fill materials shall be placed such that the thickness of loose materials does not exceed 10 inches and the compacted lift thickness does not exceed 8 inches. Compaction as specified above, shall be obtained by the use of sheepsfoot rollers, multiple -wheel pneumatic -tired rollers, or other equipment approved by the Soils Engineer for soils classifying as CL or SC. Granular fill shall be compacted using vibratory equipment or other equipment approved by the Soils Engineer. Compaction shall be accomplished while the fill material is at the specified moisture content. Compaction of each layer shall SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLIT JOB NO. GS -3347 C-2 be continuous over the entire area. Compaction equipment shall make sufficient trips to ensure that the required density is obtained. 9. MOISTURE CONTENT AND DENSITY CRITERIA Fill soils shall be moisture conditioned to between 2 percent below and 2 percent above optimum moisture content. Fill placed outside building footprints shall be substantially compacted to at least 95 percent of maximum ASTM D 698 (AASHTO T 99) dry density. Material in fills deeper than 10 feet should be compacted to 100 percent of maximum ASTM D 698 dry density. Additional criteria for acceptance are presented in DENSITY TESTS. 10. COMPACTION OF SLOPES Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until slopes are stable, but not too dense for planting, and there is no appreciable amount of loose soils on the slopes. Compactionof slopes may be done progressively in increments of three to five feet (3' to 5') in height or after the fill is brought to its total height. Permanent fill slopes shall not exceed. 2:1 (horizontal to vertical). 11. PLACEMENT OF FILL ON NATURAL SLOPES Where natural slopes are steeper than 20 percent in grade and the placement of fill is required, cut benches shall be provided at the rate of one bench for each 5 feet in height (minimum of two benches). Benches shall be at least 10 feet in width. Larger bench widths may be required by the Engineer. Fill shall be placed on completed benches as outlined within this specification. 12. DENSITY TESTS Field density tests shall be made by the Soils Engineer at locations and depths of his choosing. Where sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches. Density tests shall be taken in compacted material belowthe disturbed surface. When density tests indicate that the density or moisture content of any layer of fill or portion thereof is below that required, the particular layer or portion shall be reworked until the required density or moisture content has been achieved. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS -3347 C-3 13. SEASONAL LIMITS No fill material shall be placed, spread or rolled while it is frozen, thawing, or during unfavorable weather conditions. When work is interrupted by heavy precipitation, fill operations shall not be resumed until the Soils Engineer indicates that the moisture content and density of previously placed materials are as specified. 14. NOTICE REGARDING START OF GRADING The Contractor shall submit notification to the Soils Engineer and Owner advising them of the start of grading operations at least three (3) days in advance of the starting date. Notification shall also be submitted at least 3 days in advance of any resumption dates when grading operations have been stopped for any reason other than adverse weather conditions. 15. REPORTING OF FIELD DENSITY TESTS Density tests made by the Soils Engineer, as specified under DENSITY TESTS above, shall be submitted progressively to the Owner. Dry density, moisture content, and percentage compaction shall be reported for each test taken. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLJT JOB NO. GS -3347 C-4 MATERIAL PROPERTIES ASPHALT CONCRETE Design assumes a strength coefficient of 0.40. • Asphalt concrete should be relatively impermeable to moisture and should be designed with 100% crushed aggregates that have a minimum of 80% of the aggregate retained on the No. 4 sieve with two mechanically fractured faces. Gradations that approach the maximum density line (within 5% between the No. 4 and 40 sieve) should be avoided. A gradation with a nominal maximum size of 3/4" developed on the fine side of the maximum density line should be used. Total void content, Void in the Mineral Aggregate (VMA) and voids filled shall be considered in the selection of the optimum asphalt cement content. The optimum asphalt content shall be selected at a total air void content of 4%. The mixture shall have a minimum VMA of 14% and voids filled that range from 65 to 80%. • Polymer modification can change the rheology and viscosity to improve pavement performance and should be considered for the upper 3 inches of collector and arterial streets. ▪ Residential streets should be fog sealed approximately 1 year after the placement of asphalt concrete at 0.1 to 0.15 gallons per square yard. • A job mix design and periodic checks on the job site shall be made to verify compliance with the specifications. AGGREGATE BASE COURSE • Design assumes a minimum Hveem stabilometer value of 77. • A Class 5 or 6 Colorado Department of Transportation (CDOT) specified aggregate base course and a Mirafi 500x or equal fabric is recommended. • Aggregate base must be moisture stable. The change in R -value from 300 psi to 100 psi exudation pressure must be 12 points or less. If the construction materials cannot meet these recommendations, then the pavement design should be evaluated based upon available materials. Materials and placement methods should conform to the requirements of Garfield County. All material planned for construction should be submitted and the applicable laboratory tests performed to verify compliance with the specifications. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS4347 D-1 CONSTRUCTION CHECKLIST The construction procedures of the pavement system is as important as the quality of the materials. Inadequate compaction of the subgrade is often the reason for early pavement failure, resulting in pavement instability, rutting, cracking, settlement and heave. We recommend the proposed pavement be constructed in the following manner. PREPARATION Subgrade Preparation • Subgrade shall be stripped of organic matter, scarified, moisture treated, and compacted. • Utility trenches and all subsequently placed fill shall also be compacted and tested prior to paving. • Final grading of the subgrade should be carefully controlled so the design cross -slope is maintained and low spots in the subgrade that could trap water are eliminated. • The existing asphalt concrete shall be either removed and wasted or crushed to less than 2 inches in size and blended into the aggregate base course for reuse as subgrade material. • The recycled base and asphalt concrete shall be compacted within 2% of optimum moisture content to at least 95% of maximum modified Proctor dry density (ASTM D 1557, AASHTO T 180). • Excess shall be wasted at the contractor's expense. Granular Soils (A-1 to A-5) • Soils shall be moisture treated between 2% below to 2% above optimum moisture content. • Soils shall be compacted to at least 95% of maximum modified Proctor dry density (ASTM D 1557, AASHTO T 180). Cohesive Soils (A-6 to A-7-6) • Soils shall be moisture treated between optimum to 2% above optimum moisture content. Soils shall be compacted to at least 95% of maximum standard Proctor dry density (ASTM D 698, AASHTO T 99). Proof Testing ▪ After final subgrade elevation has been reached and the subgrade compacted, the area shall be proof -rolled with a pneumatic -tired vehicle loaded to at least 18 kips per axle. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTUT JOB NO. GS -3347 D-2 • Subgrade that is pumping or deforming shall be scarified, moisture conditioned, and tested. • If areas of very soft or wet subgrade are found, the material shall be subexcavated and replaced with approved on-site or import material, moisture conditioned, compacted and tested. Construction Observation Where soft, yielding subgrade is encountered, the excavation shall be inspected by a representative of CTL/Thompson, Inc. • CTL/Thompson shall be notified and tests taken to confirm whether the subgrade substantially meets the specifications. AGGREGATE BASE COURSE Geotextile fabric (Mirafi 500X or equal) should be placed over the approved subgrade within 24 hours prior to placement of aggregate base. • Fabric shown on the plans shall be rolled out longitudinally with minimum overlapped seams of 2.5 feet. No wrinkles will be permitted. The subgrade shall be smooth and free of ruts or other grade variations which could affect the fabric. • Placement of the fabric shall be inspected. • CDOT Class 5 or 6 Aggregate base course shall be laid in thin, loose lifts, moisture treated to within 2% of optimum moisture content, and compacted to at least 95% of maximum modified Proctor dry density (ASTM D 1557, AASHTO T 180). CURB AND GUTTER • Curb and gutter shall be backfilled and the backfill compacted to reduce the potential of heave or settlement that would cause water to pond adjacent to the pavement. Compaction shall be in accordance with Section 203.11 of the State of Colorado Standard Specifications for Road and Bridge Construction and Arapahoe County specifications. • An asphalt cement tack coat should be applied to the curb, subgrade and all joints at a rate of not more than 0.10 gallon per square yard. The tack should be applied at a temperature between 80°F and 130°F and allowed to cure for at least 1/2 hour prior to paving. ASPHALT CONCRETE Asphalt concrete shall be hot plant -mixed material compacted to at least 93 to 96% of maximum theoretical density. SPRING VALLEY DEVELOPMENT, INC, PHASE I ROADS SPRING VALLEY RANCH CTL/T JOB NO. GS -7347 D-3 Paving should only be performed when subgrade temperatures are high enough to allow proper compaction of the lift. General guidelines are often for subgrade temperatures above 40° F and air temperatures at least 40° F and rising. The temperature at laydown time shall be determined according to the temperature -viscosity relationship of the asphalt cement. Experience indicates that the laydown temperature shall be at least 275° F for AC - 10 asphalt cement. The maximum compacted lift should be 3.0 inches and joints shall be staggered. No joints shall be placed within wheel paths. Surface shall be sealed with a finish roller prior to the mix cooling to 175° F. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTLR JOB NO, GS -3347 D-4 APPENDIX E GUIDELINE MAINTENANCE RECOMMENDATIONS SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTUT JOB NO. GS -3347 MAINTENANCE RECOMMENDATIONS FOR FLEXIBLE PAVEMENTS The primary cause for deterioration of low traffic volume pavements is oxidative aging resulting in brittle pavements. Tire Toads from traffic are necessary to "work" or knead the asphalt concrete to keep it flexible and rejuvenated. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal or rejuvenating the asphalt binder to extend pavement life. The primary cause for deterioration of high traffic volume pavements is loss of integrity of the asphalt concrete and subgrade failure. High volumes also create pavement rutting and smooth, polished surfaces. Preventive maintenance treatments will typically preserve the original or existing pavement by providing a protective seal and improving skid resistance through a new wearing course. 1. Annual Preventive Maintenance a. , Visual pavement evaluations shall be performed each spring or fall. b. Reports documenting the progress of distress shall be kept current to provide information on effective times to apply preventive maintenance treatments. c. Crack sealing shall be performed annually as new cracks appear. 2. 3 to 5 Year Preventive Maintenance a. The owner should budget for a preventive treatment at approximate intervals of 3 to 5 years to reduce oxidative embrittlement problems. b. Typical preventive maintenance treatments include chip seals, fog seals, slurry seals and crack sealing. 3. 5 to 10 Year Corrective Maintenance a. Corrective maintenance may be necessary, as dictated by the pavement condition, to correct rutting, cracking and structurally failed areas. b. Corrective maintenance may include full depth patching, milling and overlays. c. In order for the pavement to provide a 20 year service life, at least one major corrective overlay can be expected. SPRING VALLEY DEVELOPMENT, INC. PHASE I ROADS SPRING VALLEY RANCH CTUT JOB NO. GS -3347 E-1 CTUThompson, Inc. 1971 West 12th Avenue Denver, Colorado 80204 (303) 825-0777 Commercial Testing Laboratories, Inc. 22 Lipan Street Denver, Colorado 80223 (303) 825-0777 CTUThompson, Inc. 5240 Mark Dabling Blvd. Colorado Springs, Colorado 80918 (719) 528-8300 CTUThompson, Inc. 234 Center Dr. Glenwood Springs, Colorado 81601 (970) 945-2809 CTUThompson, Inc. 375 E. Horsetooth Rd. The Shores Office Park Building 3, Suite 100 Ft. Collins, Colorado 80525 (970) 206-9455 CTUThompson, Inc. 4718 N. Elizabeth Street, Suite C-2 Pueblo, Colorado 81008 (719) 595-1287