NV.FLAP.US50(1).Round Hill Pines.Pavement Report.2019.rev.pdf

Lake Tahoe Basin National Forest NV FLAP US50(1) Round Hill Pines Access Road

PAVEMENT AND MATERIALS REPORT

August 2019

Report Prepared By U.S. Department of Transportation Federal Highway Administration

Central Federal Lands Highway Division Lakewood, Colorado ii

Written by: ________________________________________________________ Marty Fey, Pavements & Materials Engineer

Reviewed by: ________________________________________________________ Mike Voth, Pavements and Materials Discipline Champion

Distribution:

Project Development Project Management Construction Materials Pavements Geotech

MARTIN CHARLES FEY

Digitally signed by MARTIN CHARLES

FEY

Date: 2019.08.27 09:49:50 -06'00'

MICHAEL D VOTH Digitally signed by MICHAEL D VOTH Date: 2019.09.06 11:09:34 -06'00' iii

TABLE OF CONTENTS

I. INTRODUCTION

II. CLIMATE

III. EXPLORATION

IV. EXISTING PAVEMENT & SOILS

V. PAVEMENT DESIGN CALCULATION INPUTS

VI. PAVEMENT RECOMMENDATIONS & DISCUSSION

VII. MATERIALS RECOMMENDATIONS

APPENDICES

A – Location Map B – Laboratory Reports and Boring Log C – Photographs D – AASHTO ’93 Flexible Pavement Design E – PG LTPPBIND Software F – Special Contract Requirements G – Preliminary Pavement Recommendation Memo H – NDOT Correspondences

I. INTRODUCTION

This report is written to document road conditions and provide pavement and materials recommendations for the planned NV FLAP US50(1) Round Hill Pines Access Road project. The project is located on US 50, south of Zephyr Cove, NV at the Round Hill Pines Resort within the Lake Tahoe Basin National Forest. See Appendix A for location map.

This project involves relocating the intersection of Round Hill Pines Access Road and US 50, widening for turn lanes on US 50, and relocating the Round Hill Pines Access Road.

US 50 work includes median left turn lanes and right turn lanes for acceleration and deceleration. Round Hill Pines Access Road work involves realigning the access road between the proposed intersection and the forest service parking area.

The Preliminary Pavement Recommendations Memo was issued in March of 2019. The memo provided the pavement recommendations as well as the proposed pay items. This memo is found in Appendix F. The pavement recommendations have been finalized and are discussed in Part VI of this report.

II. CLIMATE

Climate data was obtained from weatherforyou.com for Zephyr Cove, NV. This data is summarized in Table 1 below. The average precipitation for this area is approximately

21.37 inches per year, much of it as snow. The project is located in a mountainous area and at an elevation that receives both snow and rain, dependent upon the time of year.

Table 1: Weather Data

Month Average

LOW (°F)

Average

HIGH (°F)

Average

MEAN (°F)

Average PRECIP. (in)

January 21 38 29 3.55 February 23 41 32 0.51

March 26 47 36 3.92 April 30 53 41 1.24 May 37 63 50 1.14 June 45 73 58 0.62 July 49 77 63 0.30

August 44 72 58 0.46 September 38 63 51 0.79

October 30 51 40 1.11 November 23 39 31 2.88 December 21 36 28 4.85

III. EXPLORATION

On December 11th and 12th, 2018 CFLHD pavement & material staff completed a field investigation which included boring and subgrade sampling. Tabor Drilling was hired through the CFLHD BPA to complete the borings. A CME-55 truck-mounted drill rig and a CME-45 track-mounted drill rig with 8” O.D. augers were used to complete the borings. Three boring locations were logged, three bulk subgrade samples were collected, and all three were tested. Prior to the investigation, CFL made a separate trip to mark proposed boring locations. CFL also called 811 for utility locations prior to the investigation. Boring locations, test results, and other information is shown in Appendix B.

Three geotechnical borings were also drilled along the base of the retaining wall and SPT samples were collected every 5 feet for settlement analysis. Logs and test results of these borings are available in a separate geotechnical report.

The primary objectives of this field investigation were as follows:

Measure and record existing pavement and subgrade layer depths;

Gather subgrade soil samples for follow-up testing to determine engineering properties;

Evaluate and record pavement distress conditions;

Evaluate roadway and project area for constructability concerns.

The information gathered as described above was used to support pavement rehabilitation, structural design, and material recommendations.

IV. EXISTING PAVEMENT & SOILS

Three pavement investigation borings were drilled. One on the shoulder of US 50 at both the north and south end of the project, and one at the base of the retaining wall in the location of the proposed intersection. Pavement and base course thickness measurements may not be representative of mainline US 50. Below is the summary of data gathered and test results (Table 2). For more complete and detailed results, see the attached logs and lab test reports.

Table 2: Summary of Sampling & Test Results

Pavement Depth

Roadbase

Depth R-value

Plasticity

Index Classification Comments

4”

6”

NP A-1-b(0), SM

3” 4” 75

NP A-2-4(0),

SM

N/A N/A 78

NP

A-2-4(0), SM

Resistivity = 17,901 ohm-cm, pH = 8.2 Resistivity values greater than 5000 ohm-cm are considered to be non-aggressive environments.

No boulders were encountered during the drilling exploration. However, because this project is located in mountainous terrain, boulders and cobbles may be encountered.

V. PAVEMENT DESIGN CALCULATION INPUTS

Design Parameters

The traffic loads and design needs for US 50 and Round Hill Pines Access Road are very different and require two separate analyses. Traffic counts were provided with the FLAP application and, along with engineering judgement, were used to developed estimates for ESALs.

Based on proposed parking availability and accounting for a reasonable amount of drop offs, an estimated ADT of 1200 was established for Round Hill Pines Access Road.

Because the resort is not open during the winter months, an adjusted annual ADT of 600 was used. We were informed that in the future, the resort may be used as a transit stop for regional buses. The pavement design of the access road has been modified to reflect this additional traffic.

The following is a summary of traffic data as well as the estimated ESALs used for design of Round Hill Pines Access Road:

2016 AADT = 600

2036 AADT = 892 (2% growth rate) % trucks = 2% Class 4 Buses, 1% Class 5 (trucks/RVs), 1% Class 8 Directional factor = 50% (no outlet, all traffic in must exit same way) Design Lane ESAL’s = 180,000

US 50 is heavily traveled and has much higher traffic loads. Current traffic survey data is available from NDOT through their TRINA application (http://ndot.maps.arcgis.com/apps/webappviewer/index.html?id=faed065cb86742af97a2c 7e4293baf42).

A 2016 ADT of 20,000 was used for design. Truck factors and growth rates were assumed from engineering judgement and NDOT criteria used in nearby projects.

The following is a summary of traffic data as well as the estimated ESALs used for design of US 50:

2016 ADT = 20,000

2039 ADT = 25,641 (1.25% growth rate) % trucks = 5.5% Directional factor = 50% (NDOT Standard) Design Lane ESAL’s = 3,600,000

VI. PAVEMENT RECOMMENDATIONS & DISCUSSION

In developing the pavement structural sections, the following criteria was used:

Table 3A: Design Criteria, Round Hill Pines Access Road Initial Serviceability 4.2 Terminal Serviceability 2.5 Design Reliability Level 75% Overall Standard Deviation 0.49 Soil Resilient Modulus (assumed excavation fill) 15,000 psi Performance Period (4R) 25 years 25-year ESAL 88,000 Calculated Structural Number (SN) 1.60

Table 3B: NDOT Design Criteria, US 50

Initial Serviceability 4.5 Terminal Serviceability 2.5 Design Reliability Level (ROW>80’) 90% Overall Standard Deviation 0.45 Soil Resilient Modulus* 11,225 psi Performance Period (3R) 20 years Lane Distribution 0.9 Percent Heavy Trucks 5.5% Annual Growth Rate 1.25% 20-year ESAL 3,600,000 Calculated Structural Number (SN) 3.56

*Per NDOT, MR = 145x10(0.0147xR)+1.23. Ravg = 75 MR = 31,179 psi. MR Max = 11,225 psi.

The following are the recommended pavement structural sections.

Table 4A: Recommended Pavement Section, Round Hill Pines Access Road Layer Thickness

HACP 4 inches (two lifts) Aggregate Base Course 4 inches

SN = 2.32

Table 4B: Recommended Pavement Section, US 50 Layer Thickness

HACP 8 inches (three lifts) Aggregate Base Course 8 inches

SN = 3.68

It is also recommended that existing lanes on mainline US 50 be milled to a depth of two inches and repaved concurrent with placing a 2” top mat on the new widening. This will allow for a homogenous look throughout the project and deliver better performance for the roadway.

Efforts were made to coordinate with NDOT for evaluation of the US 50 pavement section. NDOT is aware and in agreement with the recommendations made in Table 4B.

See Appendix H for email records.

VII. MATERIALS RECOMMENDATIONS

Selection of Asphalt Binder

LTPPBind software was utilized to assist in the selection of asphalt binder. The information presented in LTPPBind is shown in Appendix E. LTPPBind and NDOT standards indicated that a PG 64-28NV binder should be used. Consideration was given to the location of the project as well as performance of past projects in similar conditions.

Prime and Tack Coats, Blotter and Fog Seal

Prime Coat and Blotter are recommended for this project. A tack coat applied between pavement lifts is recommended. It is also recommended that a fog seal be applied to the final surfacing.

Drainage and Subexcavation

During the field investigation no areas of pavement distress were observed. Additionally, no major water damage or drainage problems pertaining to the existing traveled way were observed. Although it is not anticipated to be needed, a nominal amount (500 CY) of subexcavation should be included in the contract. This quantity should remain in the contract in the event that areas in need of repair are encountered.

Bid Items

Suggested FP-14 pay items for the proposed structural section are shown in Table 5 below.

Table 5: Recommended Pay Items Item Number Item Description Unit

20402-0000 Subexcavation CUYD

30202-2000 Roadway Aggregate, Method 2 TON

40301-0100 Hot Asphalt Concrete Pavement, Type 1 TON

40601-0000 Fog Seal TON

41102-0000 Prime Coat SQYD

41105-0000 Blotter TON

41201-0000 Tack Coat TON

Construction Considerations & Special Contract Provisions

CFLHD standard SCR’s related to pavements & materials will be used. The attached SCRs (Appendix F) for Section 204. – Unclassified Borrow, Section 702. – Asphalt Materials, and Section 704. - Soil should be used.

APPENDICES

A – Location Map

B – Laboratory Reports and Boring Log

C – Photographs

D – AASHTO ’93 Flexible Pavement Design

E – PG LTPPBind Software

F – Special Contract Requirements

G – Preliminary Pavement Recommendation Memo

H – NDOT Correspondences

Appendix A: Location Map

Appendix B: Laboratory Reports and Boring Logs

Project:

Sample Number

Station or Location

Offset (from c/l)

Date Sampled

Depth of Bore

Container Type

Pavement Depth

Base Depth

R-Value Soil Class

0 to 4" 4" 4" to 10" 6" 66

4" to 5' 82 A-1-b(0), SM

0 to 3" 3" 3" to 7" 4" 7" to 5' 75 A-2-4(0), SM

0 to 4" N/A N/A 4" to 5' 78 A-2-4(0), SM

Note: Grey background indicates sample depth location.

W shoulder os US 50, near entrance

B-1 5' 5-gal bucket Sand silty, brown, moist

Date of Investigation:Investigation By:Marty Fey Marty Fey

12/12/201830'LT

45'LT

Base of retaining wall, at new entrance

B-4

Investigation Boring & Sampling

Resistivity = 17,901 ohm x cm, pH = 8.2

Soil: A-2-4(0), SM; LL=NV, PI=NP; 127.6pcf@9.0%mcB-2

W shoulder of US 50, N end of project

32'LT 12/12/2018

Sand silty, brown, moist

NV FLAP US50(1) Round Hill Pines Access Road Account Number:

Entered By:

5' 5-gal bucket

Asphalt Roadbase, reddish brown Sand silty, brown, moist

5-gal bucket5'12/11/2018

12/11/2018 and 12/12/2018 Pavement Investigation - Shallow Borings

Asphalt Roadbase, brown

Topsoil, brown Soil: A-2-4(0), SM; LL=NV, PI=NP; 117.5pcf@9.8%mc

Boring Observations (grey = sample depth )

Soil: A-1-b(0), SM; LL=NV, PI=NP; 130.7pcf@7.7%mc

Test Results Comments

Appendix C: Photographs

Photo 1: Tabor Drilling performing drilling operations.

Photos 2 and 3: Site of future access road.

Appendix D: AASHTO ’93 Flexible Pavement Design

AASHTO FLEXIBLE PAVEMENT DESIGN Round Hill Pines Access Road SN Determination

Design Inputs W18 = 180,000 ESALs Applications Over Design Period Typ. Range 50k to 10 million

R = 75 % Reliability Typ. Range 75 to 95%

So = 0.49 Standard Deviation AASHTO Standard

MR = 15,000 psi Subgrade Resilient Modulus Typ. Range 3000 to 15000 psi

Pi = 4.2 Initial Serviceability Typ. Range 4.2 to 4.4

Pt = 2.5 Terminal Serviceability Typ. Range 2.0 to 3.0

DESIGN SN = 1.81

Subgrade assumed to be select borrow fill.

AASHTO FLEXIBLE PAVEMENT DESIGN Round Hill Pines Access Road Layer Thickness Determination Using Trial and Error

Layer Drainage Layer Layer No. Description Coefficient, ai Coefficient, mi Thickness, in SN

(topmost) Layer 1 AC Layer 0.44 1.00 4.00 1.76 Layer 2 Coarse Agg Base 0.14 1.00 4.00 0.56 Layer 3 Gran. Subbase 0.12 1.00 0.00 0.00 Layer 4 Select Borrow 0.08 0.90 0.00 0.00 Layer 5 0.00 Layer 6 0.00 Layer 7 0.00

(bottommost) Layer 8 0.00 Subgrade Subgrade N/A N/A N/A N/A

AC Layer 401 = 0.44 Trial SN 2.32 403 = 0.40

CAB 301 = 0.14 Design SN to Match 1.81 Subbase/Minor agg 302 = 0.12 FDR 304 = 0.12 Design is sufficient Select borrow 204 = 0.06 to 0.08 (Refer to Exhibit 11.2-C in Chapter 11 of PDDM for additional guidance on coefficients)

R-Value = 82 S1 = 9.820 MR = 37476 R-Value = 75 S1 = 9.200 MR = 29812 R-Value = 78 S1 = 9.466 MR = 32883

R-Value Correlation to Resilient Modulus*

Only change the R-values in C4 or C5. The rest is automatically calculated.

*CDOT method. Similar to results from Figure FF.6 in Volume 2 of AGDPS and used by CFLHD.

AADT 600 Annual Growth 0.02 Design Years 25

Directional Distribution

0.5

Lane Distribution

Classification Percent Truck Factor

Growth Factor ADT Yr 1 Design Lane ESALs ADT at N

Autos 76.0% 0.0006 456 0 748 Values Pickups, Vans 20.0% 0.004 32.0303 120 2806 197

984 (calculated) Class 4 buses 2.0% 1.5 32.0303 12 105220 20 600 Class 5 trucks/RVs 1.0% 0.5 32.0303 6 17537 10

2016 Class 6 0.0% 1 32.0303 0 0 0 2041 Class 8 1.0% 1.5 32.0303 6 52610 10

2 Class 9 0.0% 2 32.0303 0 0 0 100.00% 178172 984

(refer to Exhibit 11.2-A in the PDDM for additional guidance on truck factors)

GR = Growth Rate (%)

Future ADT Calculation ADTf = ADTi (1 + GR)(F-I)

ADTf = Average daily traffic for future year ADTi = Average daily traffic for initial year

I = Initial year for ADT F = Future year for ADT

AASHTO FLEXIBLE PAVEMENT DESIGN US 50

SN Determination

Design Inputs W18 = 3,600,000 ESALs Applications Over Design Period Typ. Range 50k to 10 million

R = 90 % Reliability Typ. Range 75 to 95%

So = 0.45 Standard Deviation AASHTO Standard

MR = 11,225 psi Subgrade Resilient Modulus Typ. Range 3000 to 15000 psi

Pi = 4.5 Initial Serviceability Typ. Range 4.2 to 4.4

Pt = 2.5 Terminal Serviceability Typ. Range 2.0 to 3.0

DESIGN SN = 3.56

Subgrade assumed to be select borrow fill.

AASHTO FLEXIBLE PAVEMENT DESIGN US 50

Layer Thickness Determination Using Trial and Error

Layer Drainage Layer Layer No. Description Coefficient, ai Coefficient, mi Thickness, in SN

(topmost) Layer 1 AC Layer 0.35 1.00 8.00 2.80 Layer 2 Coarse Agg Base 0.11 1.00 8.00 0.88 Layer 3 0.00 Layer 4 0.00 Layer 5 0.00 Layer 6 0.00 Layer 7 0.00

(bottommost) Layer 8 0.00 Subgrade Subgrade N/A N/A N/A N/A

Trial SN 3.68

Design SN to Match 3.56

Design is sufficient

R-Value = 82 S1 = 9.820 MR = 37476 R-Value = 75 S1 = 9.200 MR = 29812 R-Value = 78 S1 = 9.466 MR = 32883

R-Value Correlation to Resilient Modulus*

Only change the R-values in C4 or C5. The rest is automatically calculated.

*CDOT method. Similar to results from Figure FF.6 in Volume 2 of AGDPS and used by CFLHD.

ADT 20000 Annual Growth 0.0125 Design Years 20

Directional Distribution

0.5

Lane Distribution

0.9

Classification Percent Truck Factor

Growth Factor ADT Yr 1 Design Lane ESALs ADT at N

Autos 74.5% 0.0006 14900 0 19102 Values Pickups, Vans 20.0% 0.004 22.562979 4000 59296 5128

25641 (calculated) Class 4 buses 1.0% 1 22.562979 200 741194 256 20000 Class 5 trucks/RVs 2.0% 0.5 22.562979 400 741194 513

2016 Class 6 1.0% 1 22.562979 200 741194 256 2036 Class 8 1.0% 1 22.562979 200 741194 256

1.25 Class 9 0.5% 1.5 22.562979 100 555895 128

100.00% 3579966 25641 GR = Growth Rate (%)

Future ADT Calculation ADTf = ADTi (1 + GR)(F-I)

ADTf = Average daily traffic for future year ADTi = Average daily traffic for initial year

I = Initial year for ADT F = Future year for ADT

Appendix H: NDOT Correspondences

From: Pan, Changlin To: Voth, Michael (FHWA) Cc: Fey, Martin (FHWA) Subject: RE: NV DOT pavement design procedure Date: Monday, March 25, 2019 1:53:33 PM Attachments: Scanned from MTADMXWC03.pdf

TRINA AADT.docx

Michael, Attached please find the NDOT Darwin calculations and supporting traffic information for your reference. The HMA thickness is between 6.5” to 7” based on the different reliability level. NDOT requires 1” OG on top of the dense graded mix at Tahoe area and it does not have a structural value for design, which will be the 1” extra HMA for the future mill and overlay to be considered.

Please let me know if you have any questions or concerns. Thank you.

Changlin (Charlie) Pan, Ph.D., P.E.

Assistant Chief Materials Engineer - Pavement | Nevada Department of Transportation 1263 South Stewart Street, Carson City, Nevada 89712

(775) 888-7789 phone | (775) 888-7501 fax cpan@dot.nv.gov| www.nevadadot.com

From: Voth, Michael (FHWA) <Michael.Voth@dot.gov> Sent: Thursday, March 21, 2019 1:05 PM To: Pan, Changlin <CPan@dot.nv.gov> Cc: Fey, Martin (FHWA) <martin.fey@dot.gov> Subject: NV DOT pavement design procedure

Hello Charlie, It was good visiting with you at the RMAU/PG meeting. As we discussed, please forward Nevada DOT’s pavement design procedures (key parameters, structural coefficients, and thresholds).

You had also mentioned you have a report for a project on US 50 in the Tahoe area. That would be a good reference for us. Please forward this report, too.

Thanks for your help!

-Mike

Mike Voth Pavement & Materials Team Leader Central Federal Lands Highway Division - FHWA 12300 W. Dakota Avenue Lakewood, CO 80228 720-963-3505 (office) 720-505-6964 (mobile)

From: Sulahria, Sajid To: Fey, Martin (FHWA) Subject: US 50 widening at Round Hill Pines Date: Monday, March 18, 2019 1:46:33 PM Attachments: 876.pdf

Contract 3310-Reduced.pdf 1316-Reduced.pdf 3216-Contract-reduced.pdf pullsheet706.docx pullsheet722.docx pullsheet729.docx pullsheet730.docx pullsheet732.docx pullsheet202.docx pullsheet207.docx pullsheet302.docx pullsheet401.docx pullsheet402.docx pullsheet403.docx pullsheet405.docx pullsheet501.docx pullsheet624.docx pullsheet625.docx pullsheet627.docx pullsheet628.docx pullsheet632.docx pullsheet636.docx pullsheet702.docx pullsheet703.docx pullsheet704.docx

Good Afternoon Marty, Attached please find as-builts / specifications and suggestions below in red.

Thank you and please let me know if you have any questions.

Regards, Sajid

From: Fey, Martin (FHWA) <martin.fey@dot.gov> Sent: Tuesday, March 12, 2019 11:53 AM To: Sulahria, Sajid <SSulahria@dot.nv.gov> Subject: US 50 widening at Round Hill Pines

Sajid, Good afternoon, I am a pavement engineer with CFL working with Braden Peters on the Round Hill Pines Resort entrance and widening of US 50. I am working on a section design for US 50 and have a couple questions I am hoping you can help answer.

1. Are as-built plans available for US 50 near Round Hill Pines? If not, do you have an idea of what pavement section is currently on the highway? Currently the project is assuming 9” HMA on 12” of ABC.

Recommendation from Materials Division - 8” Type 2 PBS on 8” of Type 1 Class B Aggregate Base should be fine for the approach in NDOT ROW. See also attached as-builts.

2. Is recent traffic study data available for US 50? We have some information, but would be curious to know NDOTs observations and predictions for future traffic levels.

Don’t believe there are any planning studies for the traffic analysis. Traffic counts are available online via our TRINA application:

http://ndot.maps.arcgis.com/apps/webappviewer/index.html?

id=faed065cb86742af97a2c7e4293baf42

3. What specifications should I design to? Our intention is to use NDOT design standards for the US 50 design. The NDOT 401 section I have is from July of 2015, is this the most current standard? Is there a different standard you would like me to use?

Attached are the current Pull sheets for 2014 Standard Specifications that would be needed for the work described (from our Specifications Section)

F.Y. I -2014 Standard Specification (Silver Book) also available on Dept. Web Page.

Thank you in advance for your help and I look forward to working with you. Please let me know if you need more information or clarification.

Marty Fey, PE Pavement and Materials Engineer Central Federal Lands-Highway Division Office: 720-963-3731 Cell: 303-819-2042 martin.fey@dot.gov

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