subsurface exploration and pavement design report · 2020. 4. 24. · subsurface exploration and...

GEOSCIENCES & ENGINEERING 7290 South Fraser Street Centennial, Colorado 80112-4286 Phone: 303-337-0338 Fax: 303-337-0247

SUBSURFACE EXPLORATION AND

PAVEMENT DESIGN REPORT

Eastlake Station – 124th Avenue Parking Lot City of Thornton, Colorado

Icon Engineering, Inc. Attn: Mr. Scott Reed, P.E.

7000 S. Yosemite Street, Suite 120 Centennial, CO 80112

March 3, 2020

Prepared For

Subsurface Exploration and Pavement Design Report (G19.1887.000) Eastlake Station – 124th Avenue Parking Lot, Thornton, Colorado Page ii

TABLE OF CONTENTS

Page 1.0 PURPOSE AND SCOPE....................................................................................................... 1 2.0 PROPOSED CONSTRUCTION .............................................................................................. 1 3.0 SITE CONDITIONS AND GEOLOGY ....................................................................................... 2 4.0 SUBSURFACE EXPLORATION .............................................................................................. 4 5.0 SUBSURFACE CONDITIONS ................................................................................................ 5 6.0 LABORATORY TESTING ...................................................................................................... 5 7.0 SITE GRADING AND EXCAVATIONS ..................................................................................... 7 8.0 PAVEMENT DESIGN RECOMMENDATIONS ............................................................................ 8 9.0 LIMITATIONS ................................................................................................................... 11

FIGURES, TABLE, AND APPENDICES Figure 1 Locations of Exploratory Borings Figure 2 Fence Diagram of Exploratory Borings Figure 3 Legend and Notes for Exploratory Borings Figure 4 Gradation Test Results Figure 5 Swell-Compression Test Results Figure 6 R-value Test Report Table 1 Summary of Laboratory Test Results Appendix A Individual Logs of Exploratory Borings Appendix B ESAL Calculations and Pavement Design Results

Subsurface Exploration and Pavement Design Report (G19.1887.000) Eastlake Station – 124th Avenue Parking Lot, Thornton, Colorado Page 1 of 11

1.0 PURPOSE AND SCOPE This report contains the results of a subsurface exploration and pavement design conducted for the proposed Eastlake Station – 124th Avenue Parking Lot Project in the City of Thornton, Colorado. A subsurface exploration was conducted to obtain information on soil and groundwater conditions. Soil samples obtained were visually classified, and selected samples were laboratory tested to evaluate strength, classification, and other engineering properties. The results of the field and laboratory testing programs were evaluated to develop geotechnical recommendations for design and construction of the proposed pavement.

This report has been prepared to summarize the data obtained and present our conclusions and

recommendations based on the proposed construction and the subsurface conditions encountered. Design parameters and a discussion of geotechnical engineering considerations related to the construction of the proposed project are included. Environmental assessments including evaluations of the occurrence or potential occurrence of hazardous materials are beyond the scope of this study. Our services were provided in general accordance with our agreement with ICON Engineering, Inc., dated June 18, 2019.

2.0 PROPOSED CONSTRUCTION The proposed Eastlake Station – 124th Avenue Parking Lot consists of a 154-space parking lot to be

constructed southwest of the intersection of 124th Avenue and York Street in the City of Thornton, Colorado. The project is expected to include minor modifications to the sidewalk south of 124th Avenue and at the intersection of 124th Avenue and York Street. Other proposed improvements for the project include lighting for the parking lot, pavement marking, landscaping, and a water quality facility. Curb and gutter is planned for all areas except for the south side of the parking lot to allow for future expansion. If the scope of the proposed construction changes, we should be notified to re-evaluate our recommendations.


3.0 SITE CONDITIONS AND GEOLOGY The site is located southwest of the East 124th Avenue and York Street intersection in the City of Thornton,

Colorado. The site has an approximate grade of less than 1% to the west based on field measurements. At the time of our field work, the site was partially covered by low vegetation and shrubs as well as some small to large trees. On site, there was a small stockpile of boulders ranging in diameter from 2 feet to 4 feet. The surrounding area is primarily residential with some areas of industrial and commercial development west of the site. North-south oriented railroad tracks run parallel to Claude Court to the west of the site. Historical data suggests that an old farmhouse foundation exists on site, but none was encountered during the field operations. Figures A and B below show a general view of the site.

Figure A: Looking northwest towards East 124th Avenue.


Figure B: Looking south from approximately the center of the site. Note the abandoned streetlamp.

The site is located upon the Colorado Piedmont physiographic province within an area of Piedmont

Lowlands with landforms characterized as low rolling uplands. Low rolling uplands are described as having subdued topography caused by a cover of eolian silt and sand.

Published geologic mapping shows unconsolidated clays and sands at the site (primarily loess underlain by

eolian sands). The yellowish-brown loess is comprised of primarily sandy silt (10 feet to 20 feet thick) and exhibits a columnar structure, is slightly calcareous, and may contain appreciable amounts of clays and silty clays. Pleistocene-Age eolian sand underlies the loess deposits in a majority of the area. These massive, very permeable deposits consist of light brown fine sand with silt and clay and are generally 10 feet to 20 feet thick. Although the map does not indicate the presence of artificial fills on site, evidence from our borings shows that a shallow layer of artificial fill (approximately less than 2 feet thick) is present at the site. The presence of fill is most likely related to land development, railroad, and roadway constructions. Published mapping of potentially swelling soil and bedrock in the Front Range Urban Corridor indicates that the area contains moderate swell potential underneath the site.


Bedrock is expected to be the Denver and Arapahoe Formations which consists of brown to bluish-gray interbedded sandstone, claystone, siltstone, and shale. Olive brown sandstone beds are characteristic of the Denver Formation. Depth to bedrock is variable but ranges from 20 feet to 40 feet.

Groundwater is estimated to be 10 feet to 20 feet below the surface. Groundwater levels can be expected

to fluctuate with varying seasonal and weather conditions.

4.0 SUBSURFACE EXPLORATION The subsurface exploration was conducted on July 30th, 2019 and consisted of drilling 2 exploratory borings

at the approximate locations shown on the attached Figure 1, Locations of Exploratory Borings. The borings were drilled to depths of 10 feet with a truck mounted CME 75 drill rig equipped with 4-inch diameter solid-stem auger. A representative of Geocal, Inc. logged the borings and collected the soil samples.

Soil samples were collected in general accordance with the ASTM standards using a nominal 2-inch inside

diameter (I.D.) Modified California sampler (ASTM D3550). The sampler was driven into the various strata with blows from a 140-pound hammer falling 30 inches. The penetration resistance values, when properly evaluated, indicate the relative consistency or density of the soils or bedrock hardness. Samples were obtained on approximate 5-foot intervals, and bulk samples of auger cuttings were collected from about 1 foot to 5 feet from each boring. Upon completion, the borings were backfilled with compacted field-mixed sand and auger cuttings.

Logs of the subsurface conditions encountered, including depths at which samples were collected and

penetration resistance values are shown on Figure 2, Fence Diagram of Exploratory Borings. Notes regarding the symbols used are presented on Figure 3, Legend and Notes for Exploratory Borings. Individual logs of the exploratory borings are provided in Appendix A.


5.0 SUBSURFACE CONDITIONS The following paragraphs provide a generalized description of the subsurface conditions encountered at the

boring locations. For more detailed information, refer to Figures 2 and 3, and the Individual Logs provided in Appendix A.

The exploratory borings encountered a layer of artificial fill at the ground surface that continued to

approximately 1½ feet below the existing grades. The artificial fill generally consisted of lean clay with variable amount sand and gravel, which was stiff, medium plastic, moist, and brown in color.

Natural sandy lean clays were encountered in both borings below the artificial fill. The natural clays were

medium stiff to stiff, medium plastic, slightly moist to moist, dark gray to red brown, and contained trace fine gravel. Natural silty sand was encountered in Boring P-2 below the lean clays which continued to the depth explored. Bedrock was not encountered in the borings at the depths explored. Groundwater was not encountered in the borings while drilling, however, groundwater levels can be expected to fluctuate with varying seasonal and climactic conditions.

6.0 LABORATORY TESTING Laboratory tests were conducted to evaluate the engineering properties of the soil samples collected during

drilling. Laboratory tests consisted of gradation, Atterberg Limits (liquid and plastic limits), moisture content, swell-compression, R-value, and water-soluble sulfates. Laboratory test results are shown on Figures 4 through 6 and summarized in Table 1.

Gradation and Atterberg Limits: The soils tested were classified in accordance with the AASHTO

Classification System and the Unified Soil Classification System (USCS, ASTM D2487). These systems are based on Liquid Limit (ASTM D423), Plastic Limit (ASTM D424) and grain size distribution (ASTM D422). These parameters provide qualitative information on the suitability of the soils for support of pavements and use in civil engineering projects. Gradation and Atterberg Limits tests results are presented on Figure 4 and summarized on Table 1.


USCS classifications for both the fill and natural soils ranged from sandy fat clay to sandy lean clay, whereas AASHTO classifications ranged from A-6 to A-7-6 with Group Indices from 5 to 23. The Atterberg Limits test also indicated that the subgrade soils tested have moderate to high plasticity.

Swell-Compression Test: A swell-compression test (ASTM D 4546) was conducted on a sample of lean

clay (A-7-6(23)) to evaluate compressibility or swell characteristics under loading and wetting. The soil sample was placed in an odometer ring between porous discs, and an initial pressure of 200 pounds per square foot (psf) was applied. After stabilization, the sample was submerged and the percent volume change measured. Incremental loading was then applied and the volume change monitored until deformation practically ceased under each load. The test results are shown on Figures 5 and indicate that the sample tested exhibited slight compression under the applied surcharge loading and wetting, and moderate compressibility under increased loading.

Resistance R-Value: This test is a measurement of the ability of a soil to resist lateral spreading due to an

applied vertical loading, and the value is used to determine the resilient modulus for pavement design. A combined sample of auger cuttings from the upper five feet of the borings was tested and the test results are shown on Figure 6. The combined sample classified as sandy lean clay and had an R-value of 12. The results indicate poor pavement support characteristics for the near surface soils encountered.

Water-Soluble Sulfates: The water-soluble sulfate test is a measurement of the potential degree of sulfate

attack on concrete exposed to the onsite soils. Sulfate solutions react with tri-calcium aluminate hydrate, which is a normal constituent of Portland cement concrete, forming calcium sulfo-aluminate hydrate with an accompanying substantial volume expansion which causes cracking. Sulfate expansion problems will typically exist when the soils have sulfate concentrations in excess of 0.10%. The severity of potential exposure is based on a range of Class 0 (negligible) to Class 3 (severe) as presented in Table 601-2 of Section 601.04 Sulfate Resistance of the 2019 Colorado Department of Transportation (CDOT) Standard Specifications for Road and Bridge Construction (CDOT Standard Specifications).

As shown on Table 1, the measured concentration of water-soluble sulfate was “Not Detected” to 0.23% for

the samples tested. The test results indicate that a Class 2 Severity of Sulfate Exposure is applicable for concrete exposed to the onsite soils.


7.0 SITE GRADING AND EXCAVATIONS

The soils encountered at the project site consisted mostly of sandy lean clay and excavation of the onsite materials should be possible with conventional heavy-duty construction equipment. A surficial layer of artificial fill was encountered in the exploratory borings and the artificial fill is expected to vary in composition and depth and will sometimes be greater in extent than what was encountered during our field work. The potential exists for deleterious or foreign materials to exist within the fill. Foreign, deleterious, or otherwise unsuitable material that is encountered should be wasted and not be used for support of the pavements.

The re-use of onsite materials will be a function of where the material is taken from and the intended use.

Most of the existing onsite soils are suitable for re-use as engineered fill. However, some isolated high plasticity clays and other deleterious material may also be encountered, which should be omitted for use as engineered fill for support of pavements. Existing vegetation, debris, and any other deleterious materials should be stripped and removed from all proposed pavement and fill areas. In fill areas, exposed surfaces should be free of mounts and depressions which could prevent uniform fill placement and compaction. New fill should be placed in uniform lift thicknesses not exceeding 8 inches and compacted. Fills should be benched and keyed into slopes that are steeper than 4H:1V.

Proper surface drainage should be provided around all permanent cuts to direct surface runoff away from

the cut face. Cut slopes and other stripped areas should be protected against erosion by re-vegetation or other methods. Cut slopes up to 10 feet high should be possible provided the slopes do not exceed 3H:1V (horizontal to vertical), and provided seepage is not encountered.

No formal stability analyses were performed to evaluate the slopes recommended above. Published

literature and our experience with similar cuts and fills indicate the recommended slopes have adequate factors of safety. If seepage is encountered, we should be advised for further evaluations. Excavations are particularly susceptible to localized instabilities if seepage is encountered and the contractor should be aware of excavation stability. Sloped excavations should conform to applicable OSHA regulations, and the contractor should assume responsibility for excavations that are safe for workers.


8.0 PAVEMENT DESIGN RECOMMENDATIONS A pavement section is a layered system designed to distribute concentrated traffic loads to the subgrade

without overstressing the subgrade soils. Performance of the pavement structure is a function of several factors including but not limited to the physical properties of the supporting soils, traffic loadings, and drainage. The pavement sections presented in this report are based on laboratory test results and have been calculated in accordance with the American Association of State Highway and Transportation Officials (AASHTO) design and the City of Thornton Standard Specifications. We have assumed that Hot Mix Asphalt Pavement (HMAP) is preferred to be consistent with the existing pavement on East 124th Avenue.

Design Traffic Loading: The 18-kip Equivalent Single Axle Load (ESAL) is the equivalent 18,000-pound

single axle loading for different vehicle types, and the design period ESAL (ESAL20) is the total equivalent loading applied to the pavement structure over the design period (20 years). A 20-year design was used for the HMAP design for the parking areas. The proposed parking lot is expected to include approximately 154 parking spaces. To estimate the Average Daily Traffic volume (ADT) for design, we assumed that each parking space would be occupied on 3 occasions daily. The design traffic loading also took into consideration up to 5 single unit trucks (delivery trucks, trash truck) and one combination truck per day. We assumed that construction would be complete 2020 and that the traffic volume would increase at an approximate 2% annual growth rate. A design lane factor of 1.0 was applied. We calculated a 20-year design ESAL of 33,076. For design, we assumed an ESAL20 of 73,000, based on the City of Thornton minimum ESAL for local roadways. The ESAL calculations are provided in the Appendix B.

Subgrade Soil Strength: The subgrade soils consist of fat clays and sandy lean clays with AASHTO classifications of A-6 to A-7-6. Laboratory test results indicate an R-value of 12 for the sample tested, which correlates to a Resilient Modulus of 3,803 psi. The classifications and R-value indicate that the soils have predominantly poor pavement support capabilities within about the top 5 feet of the existing ground surface.

The following additional design parameters for a flexible (asphalt) pavement design were used:

General Value Initial Serviceability 4.5 Terminal Serviceability 2.0 Reliability Level 75% Soils Resilient Modulus (MR) (R-Value of 12) 3,803psi


Asphalt Value Structural Layer Coefficient, HMAP 0.44 Structural Layer Coefficient, Class 6 ABC 0.11 Overall Standard Deviation 0.44 Drainage Coefficient 1.0

Pavement Thickness Recommendation: The design procedure for flexible pavements is based on the

1993 AASHTO Guide for Design of Pavement Structures. Windows Pavement Analysis Software (WinPAS12) was used to calculate the composite asphalt and base course thicknesses for the proposed parking lot. The ESAL calculations and HMAP pavement design printouts are included in Appendix B. Tensar® SpectraPave software was used to calculate an alternative pavement section with a geogrid stabilized aggregate base course layer. The recommended flexible pavement sections are:

Pavement Type Asphalt (HMAP) Layer

Thickness (inches) Aggregate Base Course (ABC)

Thickness (inches) HMAP over ABC 4½ 6 HMAP over ABC w/ Geogrid 3 6* NOTE: (*) Indicates ABC stabilization by Tensar® TX5 or equivalent geogrid.

Hot Mix Asphalt Pavement (HMAP): HMAP should consist of a bituminous plant mix composed of a

mixture of aggregate and bituminous material that meets the requirements of a job-mix formula established by a qualified engineer in accordance with CDOT Standard Specifications. The following grading and binder types are recommended for this project:

Top Lift SX(50) PG 58-28 Lower Lift S(50) PG 58-28

Grading SX has a finer aggregate gradation than Grading S and is recommended for use in the top layer.

This layer may help reduce surface water penetration and oxidation of the HMAP surface, which may in turn help reduce long-term maintenance. To reduce the number of mixes used on this project, Grading SX may also be considered for use in the lower lifts.

Aggregate Base Course (ABC): Aggregate base course material should meet specifications in

accordance with the CDOT Standard Specifications for Class 6 ABC and have a minimum R-value of 78. The material should be compacted to at least 95% of the maximum density as determined by AASHTO T-180.

Geogrid Stabilized ABC: The recommended stabilized, composite pavement section was calculated using

Tensar® TX5 geogrid, placed below the ABC layer. The SpectraPave software printouts are include in Appendix B.


Other geogrid manufacturers are available, and we do not endorse any manufacturer. Therefore, the geogrid used should be Tensar® TX5 or equivalent.

Subgrade Preparation: The onsite soils should be suitable for support of the new pavements. During

construction, the pavement subgrade should be observed and any debris, vegetation, or localized unsuitable material should be removed to a minimum depth of 2 feet below the pavement subgrade and be replaced with non-expansive, granular soils meeting the minimum strength requirements (R-value of 12 or better). New fill should be uniformly moisture conditioned to within ±2% of the optimum moisture content and compacted to at least 95% of the maximum standard Proctor density (AASHTO T-99). Most of the onsite soils should be suitable for reuse as engineered full for support of pavements and for common embankment, provided the replacement material meets the minimum strength requirements.

Proof Roll: Prior to paving or placing aggregate base course or geogrid, the upper 8 inches of the

subgrade should be uniformly scarified, moisture conditioned, and compacted as specified in Section 508.2 of the COT Standard Specifications. The pavement subgrade should be thoroughly proof-rolled with a heavily loaded pneumatic tired vehicle. Areas that deform (rut or deflect) excessively under the wheel loads should be removed and replaced prior to paving. Proof-rolled areas should be paved within 48 hours or less. If precipitation occurs after the proof-roll and prior to paving, then the area should be dried and again be proof-rolled as necessary.

Drainage and Frost Potential: The collection and diversion of surface drainage away from paved areas is

extremely important to the satisfactory performance of the pavement. The design of surface drainage should be carefully considered to remove all water from paved areas. Groundwater was not encountered in the borings while drilling, and pavement subsurface drains should not be needed. The near-surface soil has low to moderate frost heave susceptibility. Frost heave potential can be reduced through proper surface drainage and construction control. Utilities should be placed prior to paving and trench backfill should be properly placed and compacted to help reduce differential settlement and subsequent distress to the pavement structure.

Maintenance: Periodic maintenance of paved areas will extend pavement life. Crack and joint sealing

should be performed on a frequent basis as new cracks appear and joint sealant fails. Chip seal, fog seal, or slurry seal applied at approximate 3-year to 5-year intervals will help reduce oxidative embrittlement problems associated with asphalt pavements. As conditions warrant, it may be necessary to perform full depth patching, milling, and overlays at approximate 10-year intervals or more frequently.


9.0 LIMITATIONS This report has been prepared in accordance with generally accepted geotechnical engineering practices

used in this area and has been prepared for design purposes. The conclusions and recommendations submitted in this report are based upon the data obtained from the borings drilled at the approximate locations shown on Figure 1. The nature and extent of variations between the exploratory borings may not become evident until excavation is performed. If during construction, subsurface conditions appear to be different from those described herein, this office should be advised so re-evaluation of the recommendations may be made.

Geocal’s professional services were performed using the degree of care and skill ordinarily exercised, under

similar circumstances, by reputable geotechnical engineers practicing in this or similar localities at the time this report was prepared in this area. No warranty expressed or implied is made. This report is not a bidding document. Any contractor reviewing this report must draw his or her own conclusions regarding site conditions and specific construction techniques to be used on this project. Geocal is not responsible for the interpretation of the site surface and subsurface conditions by others that are not consistent with the contents of this report.

Explorations into the occurrence or potential occurrence of hazardous materials, or other environmental

assessments that may be applicable to the site are beyond the scope of services represented by this report. On-site observation of excavations and testing of geotechnical materials by a representative of this office is recommended.

PROJECT NO. G19.1887.000 EAST LAKE STATION-124TH AVE PARKING LOT LOCATIONS OF EXPLORATORY BORINGS FIGURE 1

0 100

APPROXIMATE SCALE (ft)

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BORING P-4 BORING P-3 BORING P-2 BORING P-1 E 47TH AVENUE

BORING P-1 BORING P-2

E 124TH AVE

0 100

APPROXIMATE SCALE (ft)

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-16

-14

-12

-10

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-6

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4-7

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5-9

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FENCE DIAGRAM OFEXPLORATORY BORINGS

FIGURE 2CLIENT Icon Engineering

PROJECT NUMBER G19.1887.000

PROJECT NAME East Lake Station - 124th Ave. Parking Lot

PROJECT LOCATION City of Thornton

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7290 South Fraser StreetCentennial, CO 80112Telephone: (303) 337-0338Fax: (303) 337-0247

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Material Description USCS AASHTO

Project No. Client: Remarks:

Project:

Location: Boring P-1 Depth: 1 foot Sample Number: 8364-1

Location: Boring P-1 Depth: 4 feet Sample Number: 8364-2

Loc.: Borings P-1 & 2 combined Depth: 1-5 feet Sample No.: 8364-3

Location: Boring P-2 Depth: 4 feet Sample Number: 8364-4

GEOCAL, INC.Figure

46 16 1.7858 0.089644 1730 14 2.5360 0.129335 14 0.2224

sandy lean clay CL A-7-6(14)lean clay CL A-7-6(23)sandy lean clay CL A-6(5)sandy lean clay CL A-6(10)

G19.1887.000 ICON Engineering

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Gradation Test Results

Eastlake Station - 124th Avenue Parking Lot

106 pcf

4 feet 19.3 %

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USCS Classification 0 psf

AASHTO Classification A-7-6(23)

JOB NO.

FIGURE NO.

Sample Location Boring B-1 Dry Density

Sample Depth Moisture Content

Sample Description Lean clay

5

G19.1887.000

GEOCAL, INC.Eastlake Station - 124th Avenue Parking Lot

SWELL - COMPRESSION TEST RESULTS

Volume Change

CL Swell Pressure

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R-VALUE TEST REPORT

R-VALUE TEST REPORT

GEOCAL, INC.

Date: 8/15/2019

Project No.: G19.1887.000

Project: Eastlake Station - 124th Avenue Parking Lot

Location: Borings P-1 & 2 combined

Sample Number: 8364-3 Depth: 1-5 feet

Remarks:

Checked by: M.Wegelin

Tested by: D.Houston

sandy lean clay

Figure 6

Material DescriptionTest Results

No.

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Pressure

psi

Density

pcf

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%

Expansion

Pressure

psi

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Press. psi

@ 160 psi

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Height

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psi

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R

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Resistance R-Value and Expansion Pressure - AASHTO T 190

Exp. pressure at 300 psi exudation pressure = 0.00 psi

R-value at 300 psi exudation pressure = 12

1 60 111.3 13.9 0.00 127 2.55 321 12 12

2 80 109.6 15.5 0.00 130 2.48 358 12 12

3 40 109.4 17.1 0.00 135 2.45 245 10 10

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Project #: Project Name:

Natural Natural Percent Swell Water R Value AASHTO

Moisture Dry Passing Liquid Plasticity Pressure Soluble at 300psi Class. Soil or Bedrock

Boring Depth Content Density Gravel Sand No. 200 Limit Index Sulfates Exudation (Group Description

No. (feet) (%) (pcf) (%) (%) Sieve (%) (%) ( psf) ( % ) Pressure Index)

P-1 1 14.2 14 28 58 46 30 Not detected A-7-6(14) Sandy lean clay

P-1 4 19.3 106 0 14 86 44 27 0 0.23 A-7-6(23) Lean clay

P-1 & 2 1-5 9.9 17 30 53 30 16 12 A-6(5) Sandy lean clay

P-2 4 14.3 114 2 36 62 35 21 A-6(10) Sandy lean clay

ICON Engineering

Eastlake Station - 124th Avenue Parking Lot

SUMMARY OF LABORATORY TEST RESULTS

TABLE 1

G19.1887.000

Atterberg LimitsSample Location Gradation

APPENDIX A

INDIVIDUAL LOGS OF EXPLORATORY BORINGS

SPT

GB

MC

MC

67

67

67

3-5-6(11)

4-7

7-11

14.2

19.3

46

44

16

17

30

27

FILL, SANDY LEAN CLAY, medium plastic, slightlymoist, brown, mostly fine to medium sand, gravelly

SANDY LEAN CLAY, stiff, medium plastic, moist, darkgray, mostly fine, few medium sand, few gravel

LEAN CLAY WITH GRAVEL, medium stiff to very stiff,medium plastic, slightly moist, red brown to light brown,mostly fine, trace gravel

Bottom of boring at 10.0 feet.

106

58

86 -0.1/0

NOTES

GROUND ELEVATION 0 ft

LOGGED BY Zane White

DRILLING CONTRACTOR Elite Drilling Services GROUND WATER LEVELS:

CHECKED BY Walter Zitz, P.E.

DATE STARTED 7/30/19 COMPLETED 7/30/19

AT END OF DRILLING ---

AFTER DRILLING ---

DRILLING METHOD SSA HOLE SIZE 4 inches AT TIME OF DRILLING --- Not Encountered

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FILL, LEAN CLAY, stiff, medium plastic, slightly moist,brown, mostly fine sand, few gravel

SANDY LEAN CLAY, medium stiff, medium plastic,slightly moist, tan

SILTY SAND, dense, moist, tan, mostly fine, fewmedium sand

Bottom of boring at 10.0 feet.

114 62

NOTES

GROUND ELEVATION 0 ft

LOGGED BY Zane White

DRILLING CONTRACTOR Elite Drilling Services GROUND WATER LEVELS:

CHECKED BY Walter Zitz, P.E.

DATE STARTED 7/30/19 COMPLETED 7/30/19

AT END OF DRILLING ---

AFTER DRILLING ---

DRILLING METHOD SSA HOLE SIZE 4 inches AT TIME OF DRILLING --- Not Encountered

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APPENDIX B

ESAL CALCULATIONS & PAVEMENT DESIGN RESULTS

Cars & Pickups Single Unit Trucks Combination Unit Trucks

0.003 0.249 1.087

Assumed Growth Rate= 2%

Number of Lanes (per direction) = 1 % in Design Lane= 100%

Precent of types 100.00% 98.68% 1.10% 0.22%

2020 ADT Estimate 462 456 5 1

Projected 2040 ADT 687 678 8 2

20-Yr Design ADT 575 567 7 1

Roadway ESAL 33,076 12,417 12,724 7,935

Design Lane ESAL20 33,076

Eastlake Station 124th Ave. Parking Lot

Vehicle Type/Classification (%)

Vehicle Type Load Factor

WinPASPavement Thickness Design According to

1993 AASHTO Guide for Design of Pavements StructuresAmerican Concrete Pavement Association

Flexible Design Inputs

Project Name:Route:

Location:Owner/Agency:

Design Engineer:

Flexible Pavement Design/Evaluation

Structural NumberTotal Flexible ESALsReliabilityOverall Standard Deviation

percent Terminal ServiceabilityInitial ServiceabilitySubgrade Resilient Modulus

Layer Pavement Design/Evaluation

LayerMaterial

LayerCoefficient

DrainageCoefficient

LayerThickness

LayerSN

Eastlake Station124th Ave Parking LotThornton, CO

Parking Lot Pavement Design

2.5473,00075.000.44

3,803.004.502.00

psi

Asphalt Cement Concrete 0.44 1.00 4.27 1.88Graded Stone Base 0.11 1.00 6.00 0.66

SN 2.54

Monday, December 16, 2019 9:25:56AM Engineer:Geocal, Inc.

SpectraPave™

Pavement Optimization Design Analysis

Project Name Eastlake Station - 124th Ave Parking Lot

Company Name Geocal

Designer N/A Date N/A

Design Parameters for AASHTO (1993) Equation

Reliability (%)

Standard Normal Deviate

Standard Deviation

= 95

= -1.645

= 0.44

Initial Serviceability

Terminal Serviceability

Change in Serviceability

= 4.5

= 2.0

= 2.5

Aggregate fill shall conform to following requirement:

D50

subsurface exploration and pavement design report · 2020. 4. 24. · subsurface exploration and...

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