Attachment_No__8_JOTR_West_Entrance_Geotechnical_Report.pdf

00137895.000A/FRE18R80241 Page 1 of 1 June 21, 2018

© 2018 Kleinfelder www.kleinfelder.com

KLEINFELDER 3731 W. Ashcroft Ave., Fresno, CA 93722 p| 559.486.0750 f| 559.442.5081

June 21, 2018 Kleinfelder Project No.: 00137895.000A/Task 04

Ms. Karen Richards Siegel & Strain Architects 1295 59th Street Emeryville, California 94608

SUBJECT: Geotechnical Engineering Investigation Report

Relocate the West Entrance Station - 214937 Joshua Tree National Park, California

Dear Ms. Richards:

The attached report presents the results of our geotechnical investigation for the proposed

West Entrance station relocation in Joshua Tree National Park, California. The report describes our study, findings, conclusions, and recommendations for planning and design.

Kleinfelder appreciates the opportunity to provide geotechnical engineering services to the

Siegel & Strain Architects and the National Park Services during the planning and design phase of this project. If there are any questions concerning the information presented in this report, please contact this office at your convenience.

Respectfully submitted, KLEINFELDER

Victoria Tinoco Romeo Shiplee, PE Staff Professional I Senior Project Engineer http://www.kleinfelder.com/

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GEOTECHNICAL INVESTIGATION REPORT

RELOCATE THE WEST ENTRANCE STATION - 214937

JOSHUA TREE NATIONAL PARK, CALIFORNIA

Prepared for:

Siegel and Strain Architects

June 21, 2018

This document was prepared for use only by the client, only for the purposes stated, and within a reasonable time from issuance. Non-commercial, educational, and scientific use of this report by regulatory agencies is regarded as a "fair use" and not a violation of copyright. Regulatory agencies may make additional copies of this document for internal use.

Copies may also be made available to the public as required by law. The reprint must acknowledge the copyright and indicate that permission to reprint has been received.

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Prepared For:

Siegel & Strain Architects

GEOTECHNICAL INVESTIGATION REPORT

RELOCATE THE WEST ENTRANCE STATION

JOSHUA TREE NATIONAL PARK, CALIFORNIA

Kleinfelder Job No.: 00137895.000A/Task 04

Prepared by:

Victoria Tinoco Staff Professional I

Romeo Shiplee, PE Senior Project Engineer

KLEINFELDER

3731 W. Ashcroft Avenue Fresno, California 93722

(559) 486-0750

June 1, 2018

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TABLE OF CONTENTS

Page

1 INTRODUCTION

1.1 GENERAL

1.2 PROPOSED CONSTRUCTION

1.3 PURPOSE AND SCOPE OF SERVICES

2 FIELD EXPLORATION AND LABORATORY TESTING

2.1 FIELD EXPLORATION

2.2 FIELD AND LABORATORY TESTING

3 SITE CONDITIONS

3.1 SITE DESCRIPTION AND SURFACE CONDITIONS

3.2 EARTH MATERIALS

3.3 GROUNDWATER CONDITIONS

4 GEOLOGIC CONDITIONS

4.1 LOCAL AND REGIONAL FAULTING

4.2 SEISMIC DESIGN CRITERIA

4.3 LIQUEFACTION POTENTIAL AND SEISMIC SETTLEMENT

5 EARTHWORK

5.1 GENERAL

5.2 SITE PREPARATION

5.2.1 Stripping

5.2.2 Existing Obstructions and Fill

5.2.3 Over-Excavation

5.2.4 Subgrade Scarification and Compaction

5.3 ENGINEERED FILL

5.3.1 Materials

5.3.2 Construction Considerations

5.4 TEMPORARY EXCAVATIONS

5.4.1 General

5.4.2 Excavations and Slopes

5.4.3 Construction Considerations

5.5 TRENCH BACKFILL

5.5.1 Materials

5.5.2 Compaction Criteria

6 DESIGN RECOMMENDATIONS

6.1 SPREAD FOUNDATIONS

6.1.1 General

6.1.2 Allowable Vertical Bearing Pressures and Settlements

6.1.3 Lateral Resistance

6.2 CONCRETE SLABS-ON-GRADE

6.2.1 Subgrade Preparation

6.2.2 Capillary and Moisture/Vapor Break

6.2.3 Conventional Slab Design

6.3 PAVEMENT DESIGN

6.3.1 Asphalt Concrete Pavement

6.3.2 Moisture Considerations

6.3.3 Construction Considerations

http://www.kleinfelder.com/ JBoudreaux Text Box iii of iv

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6.3.4 Corrosion Potential

6.4 SITE DRAINAGE

7 LIMITATIONS

FIGURES

SITE VICINITY MAP 1

EXPLORATION LOCATION MAP 2

APPENDIX A

GRAPHICS KEY A-1

SOIL DESCRIPTION KEY A-2

BORING AND TEST PIT LOGS A-3/A-9

APPENDIX B

LABORATORY SUMMARY TABLE B-1

GRAIN SIZE DISTRIBUTION B-2

RESISTANCE VALUE TEST B-3/B-5

JBoudreaux Text Box iv of iv

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1 INTRODUCTION

1.1 GENERAL

This report presents the results of our geotechnical investigation for the proposed relocation of the west entrance to be located within Joshua Tree National Park, California. The report describes our study, findings, conclusions, and recommendations for planning and design.

The site is located just southeast of the existing entrance Joshua Tree National Park along Park

Boulevard. The Site Vicinity Map, presented on Figure 1, shows the approximate location of the project and the Exploration Location Map, presented on Figure 2, shows the approximate boring locations for this study.

The conclusions and recommendations presented in this report are based on subsurface conditions encountered at the locations of exploration, as well as the provisions and requirements outlined in the “Additional Services” and “Limitations” Sections of this report.

Recommendations presented herein should not be extrapolated to other areas or used for other projects without prior review by Kleinfelder.

1.2 PROPOSED CONSTRUCTION

The proposed relocation of the West Entrance Station will consist of the construction of two (2) new structures for the entrance including a fee collection station to be placed within the roadway and an additional building to house a counting office, staff restroom and additional storage space. All single-story structures are anticipated to be supported by shallow spread footings. Appurtenant construction includes road widening to make room for vehicles passing the relocated entrance and the addition of parking stalls for both staff and visitors.

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1.3 PURPOSE AND SCOPE OF SERVICES

The purpose of this investigation was to explore the site subsurface conditions and provide comments and recommendations to aid in project planning and design. The authorized scope of work was outlined in Kleinfelder’s proposal dated November 28, 2017 and included the following tasks.

• Field exploration consisting of seven (7) test borings;

• Laboratory testing;

• Engineering analysis and preparation; and,

• Preparation of this report, which include;

o A description of the proposed project, including a vicinity map and a site plan showing the boring and test pit/percolation test locations.

o A description of the site surface and subsurface conditions encountered during the field investigation, including boring and test pit logs.

o A summary of the field exploration and laboratory testing data.

o Recommendations for site preparation and earthwork grading including a discussion concerning the use of on-site soils for engineered fill recommendations for import fill specifications, and over-excavation requirements (if any).

o Recommendations for allowable bearing and settlement for shallow spread footings for the structures.

o Parameters for lateral capacity of foundations.

o Recommended subgrade preparation for concrete building slabs-on-grade.

o Recommended minimum flexible pavement sections, based on a range of traffic conditions.

o Seismic design parameters and other requirements for site based on 2016 CBC.

o Comments on regional and local groundwater levels.

o Comments on the general corrosion characteristics of the site soils.

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2 FIELD EXPLORATION AND LABORATORY TESTING

2.1 FIELD EXPLORATION

The field exploration, conducted on May 21, 2018, consisted of a total of seven (7) exploratory test borings. The test borings were drilled with a Mobile B-52 truck-mounted drill rig using hollow stem auger techniques. The borings extended to depths ranging from approximately 5 to 31½ feet below the existing ground surface. The approximate locations of the borings are indicated on the Exploration Location Map, Figure 2.

The soils encountered in the borings were visually classified in the field and a continuous log was recorded. Samples of the subsurface material were obtained using a 1.4-inch I.D. standard penetrometer, driven 18 inches in accordance with ASTM D1586 test procedures. The sampler was used without liners. Resistance to sampler penetration was noted on the boring logs as the number of blows per foot over the last 12 inches of sampler penetration. The blow counts listed in the boring logs have not been corrected for the effects of overburden pressure, rod length, sampler size, or hammer efficiency. Bulk samples were also obtained from auger cuttings at selected boring locations. At completion of the exploration, the borings were backfilled with the soil cuttings.

2.2 FIELD AND LABORATORY TESTING

Penetration rates, determined in general accordance with ASTM D1586, were used to aid in evaluating the consistency, compression, and strength characteristics of the foundation soils.

Laboratory tests were performed on selected near surface samples to evaluate certain physical characteristics. The following laboratory tests were used to develop the design geotechnical parameters:

Moisture Content (ASTM D2216)

Grain-Size Distribution (ASTM D422, without hydrometer)

Resistance Value (California Test Method No. 301)

Soluble Sulfate and Chloride Content (California Test Method Nos. 417 and 422) pH and Minimum Resistivity (California Test Method No. 643)

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The in-situ moisture content test results are shown on the boring logs in Appendix A. The soluble sulfate, soluble chloride, pH and resistivity results are summarized in the “Corrosion

Potential” Section (Section 6.4). The remaining test results are provided in Appendix B.

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3 SITE CONDITIONS

3.1 SITE DESCRIPTION AND SURFACE CONDITIONS

The project site is located within Joshua Tree National Park in California just southeast of the existing park entrance on Park Boulevard. The site is bound to the west by the existing park entrance and by undisturbed natural desert in all other directions. In general, the site topography varied from flat to gently rolling. Native vegetation was present throughout a majority of the site and large sloping hills were present in all directions.

3.2 EARTH MATERIALS

The earth material consists of Pleistocene aged older alluvial surficial sediments. The general profile encountered by the subsurface exploration consisted of silty sand with varying degrees of fines to termination depths ranging from 5 to 31½ feet below ground surface. The granular soils generally were medium dense.

The above is a general description of the earth material profile. A more detailed representation of the stratigraphy at the specific exploration locations is provided on the boring logs in

Appendix A.

3.3 GROUNDWATER CONDITIONS

Groundwater was not encountered within the explorations for this study. It is possible that groundwater conditions at the site could change at some time in the future due to variations in rainfall, groundwater withdrawal or recharge, construction activities, or other factors not apparent at the time the test borings were explored. Groundwater is not anticipated to substantially affect design or construction.

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4 GEOLOGIC CONDITIONS

4.1 LOCAL AND REGIONAL FAULTING

The project site and its vicinity are located in an area characterized by low to moderate seismic activity, but with the potential for relatively high activity. The site is located approximately 11 km east of an Alquist-Priolo Earthquake Fault Zone and several active faults are located near the site. A major seismic event on these faults could cause ground shaking at the site.

Table 4.1-1 presents a list of the most significant faults within approximately 60 km of the alignment, and their respective moment magnitudes. The distances were calculated, and the magnitudes obtained for these faults using the current Caltrans ARS Online (V2.3.07) Web site:

http://dap3.dot.ca.gov/shake_stable/v2/index.php.

TABLE 4.1-1

Significant Faults and Estimated Moment Magnitudes

Fault

Approximate

Distance from

Project* km

Maximum Credible

Earthquake

(Moment Magnitude, Mw)

Eastern Shear 10 7.6

Pinto Mountain 6 7.2

Joshua Tree 4 6.5

Emerson-Copper Mountain 10 7.0

4.2 SEISMIC DESIGN CRITERIA

For a 2016 CBC based design, the estimated Maximum Considered Earthquake (MCE) mapped spectral accelerations for 0.2 second and 1 second periods (SS and S1), associated soil amplification factors (Fa and Fv), and mapped peak ground acceleration (PGA) are presented in Table 4.1-1. Corresponding site modified (SMS and SM1) and design (SDS and SD1) spectral accelerations, PGA modification coefficient (FPGA), PGAM, risk coefficients (CRS and

CR1), and long-period transition period (TL) are also presented in Table 4.2-1. Presented values

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TABLE 4.2-1

Ground Motion Parameters Based on 2016 CBC/ASCE 7-10

Parameter Value

SS 1.628 g

S1 0.640 g

Site Class D

Seismic Design Category D

Fa 1.000

Fv 1.500

SMS 1.628 g

SM1 0.961 g

SDS 1.085 g

SD1 0.640 g

PGA 0.628

FPGA 1.000

PGAm 0.628 g

CRS 1.007

CR1 0.994

TL 8 seconds

A maximum moment magnitude (Mmax) associated with ground shaking is anticipated to be 6.7, based on the 2008 USGS Interactive Deaggregation tool.

http://geohazards.usgs.gov/designmaps/us/

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4.3 LIQUEFACTION POTENTIAL AND SEISMIC SETTLEMENT

In order for liquefaction and possible associated settlement of soils due to ground shaking to occur, it is generally accepted that four conditions will exist:

• The subsurface soils are in a relatively loose state,

• The soils are saturated,

• The soils are non-plastic,

• Ground shaking is of sufficient intensity to act as a triggering mechanism.

Considering the absence of groundwater in the upper 50 feet, the subsurface conditions encountered, and the anticipated ground motion, liquefaction and seismically induced settlement is considered unlikely.

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5 EARTHWORK

5.1 GENERAL

Based on the laboratory data, field exploration, and geotechnical analyses conducted by

Kleinfelder for this study, it is geotechnically feasible to develop the site using conventional grading and foundation construction techniques. All references to compaction, maximum density and optimum moisture content are based on ASTM D1557, unless otherwise noted.

5.2 SITE PREPARATION

5.2.1 Stripping

All surface vegetation, and any miscellaneous surface obstructions, which are not to remain, should be removed from the project area, prior to any site grading. It is anticipated stripping of vegetation could involve the upper 3 to 4 inches. Surface stripping should not be incorporated into fill unless they can be sufficiently blended to result in an organic content less 3 percent by weight (ASTM D2974).

5.2.2 Existing Obstructions and Fill

During the initial site grading, a reasonable search should be conducted to locate and remove any unsuitable material, unengineered fill or soil disturbed by previous activity that may exist within the area of construction. Removal of vegetation and root system will result in loose/disturbed soils, which will require recompaction in areas of fill or shallow cut. If any areas or pockets of soft or unstable soils are encountered, they should be over-excavated to firm native material approved by a representative of the project Geotechnical Engineer. Excavations for removal of unsuitable conditions should be backfilled with engineered fill (see Sections 5.2.4 and 5.3).

5.2.3 Over-Excavation

Over-excavation is typically reserved for soils that, in their natural state, will not provide adequate bearing for structures. The native soils at the project site should provide adequate bearing for the proposed structures. Therefore, provided the recommendations provided in

Sections 5.2 are followed, no general site over-excavation is required.

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In pavement or unpaved access road areas, the top foot of soil should be removed followed by scarification, moisture conditioning, and compaction of the exposed soils. On-site soils may then be placed and compacted over the compacted subgrade to achieve the required site grades.

Recommendations for placement and compaction of non-expansive engineered fill are presented in Section 5.3.1, Non-expansive Engineered Fill. Recommendations for placement and compaction of general engineered fill composed of on-site soils are presented in Section

5.3.2, General Engineered Fill.

5.2.4 Subgrade Scarification and Compaction

Soils used for engineered fill should be uniformly moisture conditioned to or above optimum moisture, placed in horizontal lifts less than 8 inches in loose thickness, and compacted to at least 90 percent relative compaction (ASTM D 1557). Disking and/or blending may be required to uniformly moisture condition soils used for engineered fill.

5.3 ENGINEERED FILL

5.3.1 Materials

All engineered fill soils should be nearly free of organic or other deleterious debris and less than

3 inches in maximum dimension. The on-site soil materials, exclusive of debris, may be used as engineered fill provided they contain less than 3 percent organics by weight (ASTM D2974).

Recommended requirements for any imported soil to be used as engineered fill, as well as applicable test procedures to verify material suitability, are provided on Table 5.3-1.

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TABLE 5.3-1

SOIL MATERIALS TEST PROCEDURES

Gradation Test Procedures

Sieve Size Percent Passing

ASTM1 Caltrans2

76 mm (3 inch) 100 C136 202

19 mm (¾ inch) 80 – 100 C136 202

No. 4 60 - 100 C136 202

No. 200 20 – 50 C136 202

Plasticity

Liquid Limit

Plasticity Index

< 25 < 9 D4318 204

Soluble Sulfates

< 2000 ppm - 417

Soluble Chloride

<300 ppm - 422

Resistivity

>3000 ohm-cm - 643

Notes:

American Society for Testing and Materials Standards

(latest edition) State of California, Department of Transportation, Standard Test Methods (latest edition)

Any imported materials to be used for engineered fill should be sampled and tested by a representative of the project Geotechnical Engineer prior to being transported to the site.

5.3.2 Construction Considerations

Should site grading be performed during or subsequent to wet weather, near-surface soils may be significantly above optimum moisture content. This condition could hamper equipment maneuverability and efforts to compact soils to the recommended compaction criteria. Disking to aerate, chemical treatment, replacement with drier material, stabilization with a geotextile fabric or grid, or other methods may be required to mitigate the affects of excessive soil

00137895.000A/FRE18R80241 Page 12 of 24 June 21, 2018 moisture and facilitate earthwork operations. Any consideration of chemical treatment (e.g.

lime) to facilitate construction would require additional soil chemistry evaluation and could affect landscape areas and some construction materials (e.g. aluminum).

If construction is performed during dry, hot, or windy weather, it may be necessary to periodically apply surface watering to facilitate fill compaction and to counter evaporative loss or re-establish moisture prior to constructing slabs (see Section 6.2.1).

5.4 TEMPORARY EXCAVATIONS

5.4.1 General

All excavations must comply with applicable local, State, and Federal safety regulations including the current OSHA Excavation and Trench Safety Standards. Construction site safety is generally the responsibility of the contractor, who shall also be solely responsible for the means, methods, and sequencing of construction operations. The information below is provided as a service to the client. Under no circumstances should the information provided be interpreted to mean that Kleinfelder is assuming responsibility for construction site safety or the contractor's activities; such responsibility is not being implied and should not be inferred.

5.4.2 Excavations and Slopes

The contractor should be aware that slope height, slope inclination, or excavation depths

(including utility trench excavations) should in no case exceed those specified in local, State, and/or Federal safety regulations (e.g., OSHA Health and Safety Standards for Excavations, 29

CFR Part 1926, or successor regulations). Such regulations are strictly enforced and, if they are not followed, the owner, contractor, and/or earthwork, and utility subcontractors could be liable for substantial penalties.

All excavations should be constructed and maintained in conformance with current OSHA requirements (29 CFR Part 1926) for a Type C soil.

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5.4.3 Construction Considerations

Heavy construction equipment, building materials, excavated soil, and vehicular traffic should be kept sufficiently away from the top of any excavation to prevent any unanticipated surcharging. If it is necessary to encroach upon the top of an excavation, Kleinfelder can provide comments on slope gradients or loads on shoring to address surcharging, if provided with the geometry. Shoring, bracing, or underpinning required for the project (if any), should be designed by a professional engineer registered in the State of California.

During wet weather, earthen berms or other methods should be used to prevent runoff water from entering all excavations. Runoff water should be collected and disposed of outside the construction limits.

5.5 TRENCH BACKFILL

5.5.1 Materials

Pipe zone backfill (i.e., bedding, haunching, and initial backfill as defined by ASTM D2321) should consist of soil compatible with design requirements for the specific types of pipes. It is recommended the project designer or pipe supplier develop the material specifications based on planned pipe types, bedding conditions, tolerable deflection, and other factors beyond the scope of this study. Randomly excavated on-site near surface soil will likely be Class III material per ASTM D2321.

Trench zone backfill (i.e., material placed between the pipe zone backfill and finished subgrade) may consist of native soil that meets the requirements for engineered fill.

5.5.2 Compaction Criteria

All trench backfill should be placed and compacted in accordance with recommendations provided above for engineered fill. Reduced compaction (85% minimum) could be specified for trench zone backfill in non-structural areas. Mechanical compaction is recommended; ponding or jetting should not be used.

Table 5.5-1 provides estimated geotechnical parameters for designers to consider in evaluating pipe zone backfill criteria that is compatible with pipe types and deformation tolerances.

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TABLE 5.5-1

PIPE ZONE BACKFILL PARAMETERS

Soil Type

Soil Stiffness Modulus (psi)

E’n (Trench

Sidewall)

E’b (Backfill)

85% Compaction

90% Compaction

On-Site Soil 5000 700 1000

Class III 5000 900 1350

E’n represents the modulus for the undisturbed natural soil and is based on relative density data by Howard (1996). E’b is the modulus for backfill derived from random excavation of on-site soil and is based on data by Hartley and Duncan (1982) and Watkins and Anderson (2000). The design E’ will be dependent upon the pipe diameter and trench width, which dictates the relative influence of E’n and E’b. Methods by Howard (1996) are suggested for evaluating the design E’.

Kleinfelder can furnish a recommended design E’, if provided with pipe diameter and specifications for trench construction.

In evaluating the maximum load (Wc) on pipes, a Kμ’ of 0.19 (K = 0.27 and μ’ = 0.70) can be used in determining the load coefficient Cd.

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6 DESIGN RECOMMENDATIONS

6.1 SPREAD FOUNDATIONS

6.1.1 General

The proposed structures may be supported by conventional shallow spread footings supported on approved undisturbed native soil or engineered fill. The following recommendations are based on the assumption that the recommendations in Section 5, “Earthwork”, have been implemented. Recommendations regarding the geotechnical aspects of building design are presented below.

6.1.2 Allowable Vertical Bearing Pressures and Settlements

Generally, two geotechnical issues determine the design bearing pressure for conventional spread footing foundations: (1) strength of the foundation soil and/or (2) tolerable settlement.

For lightly loaded structures, design bearing may be dictated by code-required minimum footing geometry or constructability considerations.

The available bearing capacity, based only on the shear strength of the soil, will be dependent upon the footing dimensions and the slope of the adjacent soil. Presented in Tables 6.1-1 are bearing expressions for foundations. In these expressions, B represents the effective foundation width (least dimension) and D is the total foundation embedment below the lowest adjacent grade (all values in feet). The expressions provided are for the allowable available bearing capacity (shear strength considerations only) for static loading (D.L + L.L.) and total combined loading (D.L. + L.L. + transient loading, such as wind or seismic).

TABLE 6.1-1

AVAILABLE VERTICAL BEARING CAPACITY

Loading Conditions Available Bearing Capacity (psf)

Static 900 B + 1670 D

Total Combined 1360 B + 2490 D

Ultimate 2725 B + 4970 D

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Analysis, based on Schmertmann, determined the following estimated static settlement based on furnished loads. The estimated settlement assumes a sustained load equal to be 100 percent of the dead plus live load. Settlement is expected to occur rapidly with load application.

TABLE 6.1-2

ESTIMATED SETTLEMENT

Footing Type Loading

(DL +LL)

Design Bearing

(psf)

Estimated Settlement

(inch)

Strip 3 klf 3000 Less than ¼

Column 20 kips 3200 Approximately ¼

A modulus of subgrade reaction, K1 (Bp = 1 foot), of 250 pci can be used for non-expansive engineered fill. The subgrade modulus is most appropriately applicable to consideration of static loads with deformations within an elastic range.

6.1.3 Lateral Resistance

Lateral loads applied to foundations can be resisted by a combination of passive lateral bearing and base friction. The allowable and ultimate passive pressures and frictional coefficients for the footings are presented in Table 6.1-3.

TABLE 6.1-3

PASSIVE PRESSURES AND FRICTIONAL COEFFICIENTS

Passive Pressures and Frictional Coefficients

Allowable Ultimate Loads

Static Loads Total Combined

Loads

Frictional Coefficient 0.47 (FS=1.5) 0.56 (FS=1.25) 0.70 (FS=1)

Passive Pressure (psf/ft of depth) 360 (FS=2) 490 (FS=1.5) 730 (FS=1)

Lateral Translation Needed to Develop Passive Pressure

0.005D 0.009D 0.023D

Note: D is the foundation depth below adjacent grade. Lateral translation will be in the same units as D.

If the deflection resulting from the strain necessary to develop the passive pressure is within structural tolerance, the passive pressure and frictional resistance can be used in combination.

Otherwise, additional passive pressure values could be provided based on tolerable deflection.

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The static values are for use with D+L loads and the total combined values are for resistance of

D+L+transient loads other than seismic. The allowable parameters include a safety factor and, as such, can be used for direct comparison of driving and resisting loads. If design approaches use a prescribed ratio of resisting loads to driving loads greater than unity, ultimate values can be used.

6.2 CONCRETE SLABS-ON-GRADE

6.2.1 Subgrade Preparation

Slabs-on-grade should be supported on non-expansive engineered fill placed as described in

Section 5 of this report. The slab subgrade, to a depth of 12 inches, should have a moisture content of at least optimum immediately prior to pouring the slab or placing a vapor retarding membrane.

6.2.2 Capillary and Moisture/Vapor Break

If the building contains component which might be adversely affected by moisture, it is recommended that the slab subgrade be covered by vapor retarding membrane, such as 10-mil polyorfin. If design should incorporate a gravel subgrade layer, the membrane should have a minimum thickness of 15-mil. The subgrade surface should be smooth, and care should be exercised to avoid tearing, ripping, or otherwise puncturing the vapor retarding membrane. If the vapor retarding membrane becomes torn or disturbed, it should be removed and replaced or properly patched. It is recommended consideration be given to placing concrete directly on the vapor retarding membrane. If desired by designers, the vapor retarding membrane could be covered with approximately 1 to 2 inches of saturated surface dry (SSD), relatively clean sand to protect it during construction. Concrete should not be placed if sand overlying the vapor barrier has been allowed to attain a moisture content greater than about 5% (due to precipitation or excessive moistening). Excessive water beneath interior floor slabs could result in future significant vapor transmission through the slab, adversely affecting moisture-sensitive floor coverings and the indoor environment.

It should be noted that, although the slab support discussed above is currently the industry standard, this system might not be completely effective in preventing floor slab moisture vapor transmission problems. This system will not necessarily assure that floor slab moisture transmission rates will meet floor-covering or equipment manufacturer standards and that

00137895.000A/FRE18R80241 Page 19 of 24 June 21, 2018 indoor humidity levels will not inhibit mold growth. A qualified specialist(s) with knowledge of slab moisture protection systems, flooring design and other potential components that may be influenced by moisture, should address these post-construction conditions separately. The purpose of a geotechnical study is to address subgrade conditions only, and consequently, it does not evaluate future potential conditions

6.2.3 Conventional Slab Design

There are no geotechnical considerations (e.g. expansive soil), which would require special design of slabs. Therefore, the thickness and reinforcement of conventional slabs-on-grade should be determined by structural considerations and should be designed by the project structural engineer or building designer. A modulus of subgrade reaction, K1 (Bp = 1 foot), of 250 pci may be used for elastic analysis of slabs on properly compacted subgrade.

Slab concrete should have good density, a low water/cement ratio, and proper curing to promote a low porosity. It is recommended the water/cement ratio not exceed 0.45 to reduce vapor transfer.

6.3 PAVEMENT DESIGN

6.3.1 Asphalt Concrete Pavement

The subgrade Resistance-value (R-value) for the on-site soil was evaluated in the laboratory on a sample of near surface soil taken from test borings R-1 through R-4. The laboratory tests were performed in conformance to Caltrans Test Method No. 301. The soil tested had a measured R-value of over 50 by exudation.

Detailed vehicular load and frequency information is not available for this project. Traffic on the site is anticipated to consist primarily of automobile traffic with regular trash collection and occasional delivery trucks. Pavement sections have been provided for Traffic Indexes (T.I.'s) of

5.0 or less, 6.0, and 7.0. These traffic design assumptions should be reviewed for compatibility with the actual development, and revised pavement sections developed, as necessary.

A design R-value of 50 is recommended for this site. The flexible asphalt concrete pavement sections associated with the assumed T.I.’s and R-value of 50 are summarized in Table 6.4-1.

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TABLE 6.4-1

RECOMMENDED MINIMUM PAVEMENT SECTIONS

Traffic

Index

Asphalt

Concrete

(inches)

Aggregate Base

(inches)

5.0 or less 2½ 4

6.0 3¼ 4

7.0 4 4½

The design criteria assume a 20-year design period and that normal maintenance (crack sealing, etc.) is performed. The traffic index is a measure of the volume of truck traffic that will be applied to a pavement section in the design life. The pavement section associated with a TI of 5.0 would be appropriate for areas subject to automobile traffic only. The allowable average daily truck traffic (ADTT) for the other assumed traffic indexes is presented in Table 6.4-2.

TABLE 6.4-2

AVERAGE DAILY TRUCK TRAFFIC

Traffic Index

2-Axle Vehicle or

3-Axle Vehicle or

5-Axle Vehicle

5.0 5.2 2.0 0.5

6.0 24.1 9.0 2.4

7.0 88.1 33.0 8.8

The flexible pavement should conform to and be placed in accordance with the latest revisions of Caltrans Standard Specifications. The aggregate base (Class 2) and aggregate subbase

(Class 2) should comply with Sections 26 of the Caltrans Standard Specifications. The aggregate base, and upper 6 inches of the non-expansive fill subgrade should be compacted to a minimum of 95 percent relative compaction as determined by the ASTM D1557 or California

Test Method 216/231 (dry method) test procedure. Subgrade compaction should be achieved immediately prior to placing the pavement section.

00137895.000A/FRE18R80241 Page 21 of 24 June 21, 2018

6.3.2 Moisture Considerations

The pavement design should consider both the vehicular loading and environmental factors.

The vehicular loading will depend on the amount and type of traffic anticipated for the pavement design life. Environmental factors include the potential for moisture variations beneath the pavement structural section. It is recommended that all pavement areas conform to the following criteria:

All trench backfill should be properly placed and adequately compacted to provide a stable subgrade.

Adequate drainage should be provided to prevent ponding of surface water which could saturate the subgrade soil.

A periodic maintenance program should be incorporated to include sealing cracks and other measures.

All concrete curbs separating pavement and landscaped areas should extend to the subgrade.

6.3.3 Construction Considerations

In the event unstable (pumping) subgrades are encountered within planned pavement areas, it is recommended a heavy, rubber-tired vehicle (typically a loaded water truck) be used to test the load/deflection characteristics of the finished subgrade materials. It is recommended this vehicle have a minimum rear axle load (at the time of testing) of 16,000 pounds with tires inflated to at least 65-psi pressure. If the tested surface shows a visible deflection extending more than about 6 inches from the wheel track at the time of loading, or a visible crack remains after loading, corrective measures should be implemented. Such measures could include disking to aerate, chemical treatment, replacement with drier material, or other methods. It is recommended Kleinfelder be retained to assist in developing which method (or methods) would be applicable for this project.

00137895.000A/FRE18R80241 Page 22 of 24 June 21, 2018

6.3.4 Corrosion Potential

Kleinfelder has completed laboratory testing to provide data regarding corrosivity of onsite soils.

Our scope of services does not include corrosion engineering. Therefore, a detailed analysis of the corrosion test results is not included in this report. A qualified corrosion engineer should be retained to review the test results and design protective systems that may be required.

Kleinfelder may be able to provide those services.

Laboratory chloride concentration, sulfate concentration, pH, and electrical resistivity tests were performed on a composite of the four near-surface bulk soil samples. The results of the tests are noted on the boring logs (Appendix A) and are summarized in Table 6.5-1. If fill materials will be imported to the project site, similar corrosion potential laboratory testing should be completed on the imported material.

TABLE 6.5-1

CHEMISTRY LABORATORY TEST RESULTS

Boring and

Depth

Material Resistivity, ohm-cm pH

Water-Soluble Ion

Concentration, ppm

Chloride Sulfate

Composite

@ 0-5 Silty Sand (SM) 6,430 7.97 1.9 1.1

Ferrous metal and concrete elements in contact with soil, whether part of a foundation or part of the supported structure, are subject to degradation due to corrosion or chemical attack.

Therefore, buried ferrous metal and concrete elements should be designed to resist corrosion and degradation based on accepted practices.

Test results are indicative of an increasingly moderate corrosive environment. Corrosion is dependent upon a complex variety of conditions, which are beyond the geotechnical practice.

Consequently, a qualified corrosion engineer should be consulted if the owner or designers desire more specific information on material types and any necessary protective measures.

The degradation of concrete or cement grout can be caused by chemical agents in the soil or groundwater that react with concrete to either dissolve the cement paste or precipitate larger compounds within the concrete, causing cracking and flaking. The concentration of water-soluble sulfates in the soils is a good indicator of the potential for chemical attack of concrete or cement grout. The American Concrete Institute (ACI) in their publication “Guide to Durable

00137895.000A/FRE18R80241 Page 23 of 24 June 21, 2018

Concrete” (ACI 201.2R-08) provides guidelines for this assessment. The results of sulfate tests indicate the potential for deterioration of concrete is negligible. Therefore, no special requirements should be necessary for the concrete mix.

6.4 SITE DRAINAGE

It is important that drainage away from the improvements be provided and maintained to prevent ponding and/or saturation of the soils in the vicinity of foundations, concrete slabs-on-grade, or pavements. Proper drainage requires a partnering between the design and construction of the facility and the ultimate maintenance personnel.

The development should incorporate the basis for good drainage. This includes:

• Sufficient pad height to allow for proper drainage.

• Defined drainage gradients away from the structures to points of conveyance, such as drainage swales and/or area drains and discharge pipe.

• Roof downspouts connected to proper areas of discharge.

The maintenance personnel for the property must maintain the established site drainage by not blocking or obstructing gradients away from the foundations and structure. The landscape personnel are also the only persons who can avoid over watering. If planted areas adjacent to the structure are desired, it is suggested that care be taken not to over irrigate and to maintain a leak-free sprinkler piping system. Well-maintained low volume emitter irrigation systems are best suited for planters adjacent to structures. Watering practices should strive to use only sufficient water to sustain and promote plant growth. All site irrigation should promote a soil moisture condition that is relatively uniform year-round.

The site soil could be susceptible to erosion. Consequently, site drainage should not be allowed to over-top slopes. Drainage which must be designed to sloped areas should be carried in pipes or paved swales to discharge points with adequate energy dissipation to prevent erosion.

00137895.000A/FRE18R80241 Page 24 of 24 June 21, 2018

7 LIMITATIONS

Recommendations contained in this report are based on the field observations and subsurface explorations, laboratory tests, and present knowledge of the proposed construction. It is possible that soil conditions could vary between or beyond the points explored. Additional soil exploration may be necessary where better definition of conditions is desired. If the scope of the proposed improvements changes from that described in this report, the recommendations provided should also be reviewed.

This report has been prepared in substantial accordance with the generally accepted geotechnical engineering practice, as it exists in the general area at the time of the study. No warranty, express or implied, is provided or intended. The recommendations provided in this report are based on the assumption that Kleinfelder will conduct an adequate program of tests and observations during the construction phase in order to evaluate compliance with the recommendations.

This report may be used only by the Siegel & Strain Architects and the National Park Services, other project subconsultants and reviewing regulatory agencies and only for the purposes stated within a reasonable time from its issuance. Land use, site conditions or other factors may change over time, and additional work may be required with the passage of time. Any other party who wishes to use this report shall notify Kleinfelder of such intended use. Based on the intended use of the report, Kleinfelder may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the client or anyone else will release Kleinfelder from any liability resulting from the misuse of this report by any unauthorized party.

SITE VICINITY MAP

RELOCATE OF WEST ENTRANCE

JOSHUA TREE NATIONAL PARK

CALIFORNIA

137895.004

06/2018

RA

VT

Figure_1.mxd

_̂̂_̂_̂_̂_̂_̂_ SITE

The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

£0 42 Miles

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PROJECT NO.

DRAWN:

DRAWN BY:

CHECKED BY:

FILE NAME:

FIGURE

www.kleinfelder.com

BORING LOCATIONS MAP

RELOCATE OF WEST ENTRANCE

JOSHUA TREE NATIONAL PARK

CALIFORNIA

137895.004

06/2018

RA

VT

Figure_2.mxd

The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

PROJECT NO.

DRAWN:

DRAWN BY:

CHECKED BY:

FILE NAME:

FIGURE

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Service Layer Credits: © 2018 Microsoft Corporation © 2018 DigitalGlobe ©CNES (2018) Distribution Airbus DS © 2018 HERE Source: Esri, DigitalGlobe, GeoEye, Earthstar Geographics, CNES/Airbus DS, USDA, USGS, AeroGRID, IGN, and the GIS User Community

LEGEND

@A Boring Location ED Bulk Sample

A-1

FIGURE

RELOCATE OF WEST ENTRANCE

JOSHUA TREE NATIONAL PARK

CALIFORNIA

The report and graphics key are an integral part of these logs. All data and interpretations in this log are subject to the explanations and limitations stated in the report.

Lines separating strata on the logs represent approximate boundaries only. Actual transitions may be gradual or differ from those shown.

No warranty is provided as to the continuity of soil or rock conditions between individual sample locations.

Logs represent general soil or rock conditions observed at the point of exploration on the date indicated.

In general, Unified Soil Classification System designations presented on the logs were based on visual classification in the field and were modified where appropriate based on gradation and index property testing.

Fine grained soils that plot within the hatched area on the Plasticity Chart, and coarse grained soils with between 5% and 12% passing the No. 200 sieve require dual USCS symbols, ie., GW-GM, GP-GM, GW-GC, GP-GC, GC-GM, SW-SM, SP-SM, SW-SC, SP-SC, SC-SM.

If sampler is not able to be driven at least 6 inches then 50/X indicates number of blows required to drive the identified sampler X inches with a 140 pound hammer falling 30 inches.

ABBREVIATIONS

WOH - Weight of Hammer WOR - Weight of Rod CL

CL-ML

GM

GC

GW

GP

GW-GM

GW-GC

CH

CLAYEY GRAVELS,

GRAVEL-SAND-CLAY MIXTURES

GRAVELS

WITH >

12%

FINES

Cu 4 and 1 Cc 3

Cu 6 and/ or 1 Cc 3

SILTY SANDS, SAND-GRAVEL-SILT

MIXTURES

CLAYEY SANDS, SAND-GRAVEL-CLAY

MIXTURES

SW-SM

CLAYEY SANDS, SAND-SILT-CLAY

MIXTURES

Cu 6 and 1 Cc 3

SC-SM

Cu 4 and 1 Cc 3

ORGANIC SILTS & ORGANIC SILTY CLAYS

OF LOW PLASTICITY

SILTS AND CLAYS

(Liquid Limit less than 50)

SILTS AND CLAYS

(Liquid Limit greater than 50)

WELL-GRADED SANDS, SAND-GRAVEL

MIXTURES WITH LITTLE OR NO FINES

POORLY GRADED SANDS,

SAND-GRAVEL MIXTURES WITH

LITTLE OR NO FINES

MH

OH

ML

GC-GM

C O

A R

S E

G R

A

IN

E D

S O

IL

S

M or e th an h al f o f m at er ia l i s la rg er th an th e

#2 s ie ve

UNIFIED SOIL CLASSIFICATION SYSTEM (ASTM D 2487)

Cu 6 and 1 Cc 3

GP-GM

GP-GC

INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY

CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS

GRAPHICS KEY

CLEAN

SANDS

WITH

<5%

FINES

G R

A V

E L

S

M or e th an h al f o f c oa rs e fr ac tio n is la rg er th an th e

#4 s ie ve

Cu 6 and/ or 1 Cc 3>

SANDS

WITH

5% TO

12%

FINES

SANDS

WITH >

12%

FINES

S A

N D

S

M or e th an h al f o f c oa rs e fr ac tio n is s m al le r th an th e

#4 s ie ve

WELL-GRADED SANDS, SAND-GRAVEL

MIXTURES WITH LITTLE FINES

Cu 4 and/ or 1 Cc 3>

CLEAN

GRAVEL

WITH

<5%

FINES

GRAVELS

WITH

5% TO

12%

FINES

OL

SP

SP-SM

SP-SC

SM

SC

WELL-GRADED GRAVELS,

GRAVEL-SAND MIXTURES WITH

LITTLE OR NO FINES

POORLY GRADED GRAVELS,

GRAVEL-SAND MIXTURES WITH

LITTLE OR NO FINES

WELL-GRADED GRAVELS,

GRAVEL-SAND MIXTURES WITH

LITTLE FINES

WELL-GRADED GRAVELS,

GRAVEL-SAND MIXTURES WITH

LITTLE CLAY FINES

POORLY GRADED GRAVELS,

GRAVEL-SAND MIXTURES WITH

LITTLE FINES

POORLY GRADED GRAVELS,

GRAVEL-SAND MIXTURES WITH

LITTLE CLAY FINES

SILTY GRAVELS, GRAVEL-SILT-SAND

MIXTURES

CLAYEY GRAVELS,

GRAVEL-SAND-CLAY-SILT MIXTURES

WELL-GRADED SANDS, SAND-GRAVEL

MIXTURES WITH LITTLE CLAY FINES

POORLY GRADED SANDS,

SAND-GRAVEL MIXTURES WITH

LITTLE CLAY FINES

SW

SW-SC

POORLY GRADED SANDS,

SAND-GRAVEL MIXTURES WITH

LITTLE FINES

Cu 4 and/ or 1 Cc 3>

F

IN

E G

R A

IN

E

D S

O

IL

S (M or e th an h al f o f m at er ia l is s m al le r th an th e

#2 s ie ve

INORGANIC SILTS AND VERY FINE SANDS, SILTY OR

CLAYEY FINE SANDS, SILTS WITH SLIGHT PLASTICITY

ORGANIC CLAYS & ORGANIC SILTS OF

MEDIUM-TO-HIGH PLASTICITY

INORGANIC CLAYS OF HIGH PLASTICITY,

FAT CLAYS

INORGANIC SILTS, MICACEOUS OR

DIATOMACEOUS FINE SAND OR SILT

INORGANIC CLAYS-SILTS OF LOW PLASTICITY, GRAVELLY

CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS

STANDARD PENETRATION SPLIT SPOON SAMPLER

(2 in. (50.8 mm.) outer diameter and 1-3/8 in. (34.9 mm.) inner diameter)

CALIFORNIA SAMPLER

(3 in. (76.2 mm.) outer diameter)

MODIFIED CALIFORNIA SAMPLER

(2 or 2-1/2 in. (50.8 or 63.5 mm.) outer diameter)

BULK / GRAB / BAG SAMPLE

SAMPLER AND DRILLING METHOD GRAPHICS

SHELBY TUBE SAMPLER

AUGER CUTTINGS

PUSH TYPE SAMPLER

HAND AUGER

SONIC CONTINUOUS SAMPLER

HQ CORE SAMPLE

(2.500 in. (63.5 mm.) core diameter)

NOTES

GROUND WATER GRAPHICS

OBSERVED SEEPAGE

WATER LEVEL (level after exploration completion)

WATER LEVEL (level where first observed)

WATER LEVEL (additional levels after exploration)

DRAWN BY:

CHECKED BY:

DATE:

REVISED: -

PROJECT NO.: 00137895

gI N

T F

IL

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K lf_ gi nt _m as te r_

P

R O

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C

T N

U M

B E

R

5.

A

O

F F

IC

E

F

IL

T E

R

F R

E S

N O gI N

T T

E M

P

LA

T E

E

:K

LF

S

T A

N D

A R

D _G

IN

T

_L

IB

R A

R Y

_2

.G

LB

[L E

G E

N D

G R

A P

H

IC

S K

E Y

U

S C

S _N

O R

_C A

L] P

LO

T

T E

D

/0

1/

:3

P M

B Y vt in oc o

CALIFORNIA

SAMPLER

(# blows/ft)

MODIFIED CA

SAMPLER

(# blows/ft)

SPT-N60

(# blows/ft)

A-2

FIGURE

RELOCATE OF WEST ENTRANCE

JOSHUA TREE NATIONAL PARK

CALIFORNIA

The thread is easy to roll and not much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. The lump or thread crumbles when drier than the plastic limit.

It takes considerable time rolling and kneading to reach the plastic limit. The thread can be rerolled several times after reaching the plastic limit. The lump or thread can be formed without crumbling when drier than the plastic limit.

30 - 50

> 50

Medium (M)

High (H)

RELATIVE

DENSITY

APPARENT

DENSITY

30 - 50

10 - 30

4 - 10

<4

>60

35 - 60

12 - 35

5 - 12

<4

>70

40 - 70

15 - 40

5 - 15

CONSISTENCY

<2

Moist

DESCRIPTION

Strongly

FIELD TEST

Alternating layers of varying material or color with the layer less than 1/4-in. thick, note thickness.

FIELD TEST

Absence of moisture, dusty, dry to the touch

Moderately

Will not crumble or break with finger pressure

Pocket Pen (tsf)

Term of

Use

<5%

With

Modifier

5 to <15%

15%

Trace <15%

15 to <30%

30%

AMOUNT

>30

Very Soft

SOIL DESCRIPTION KEY

DESCRIPTION

Damp but no visible water

Boulders

Cobbles coarse fine Gravel

Sand

Fines

GRAIN SIZE

>12 in. (304.8 mm.)

3 - 12 in. (76.2 - 304.8 mm.) Fist-sized to basketball-sized

3/4 -3 in. (19 - 76.2 mm.) Thumb-sized to fist-sized

0.19 - 0.75 in. (4.8 - 19 mm.) Pea-sized to thumb-sized

0.079 - 0.19 in. (2 - 4.9 mm.)#10 - #4

0.017 - 0.079 in. (0.43 - 2 mm.)

#200 - #40 coarse fine medium

SIEVE SIZE APPROXIMATE SIZE

Larger than basketball-sized>12 in. (304.8 mm.)

3 - 12 in. (76.2 - 304.8 mm.)

3/4 -3 in. (19 - 76.2 mm.)

#4 - 3/4 in. (#4 - 19 mm.)

Rock salt-sized to pea-sized

#40 - #10 Sugar-sized to rock salt-sized

0.0029 - 0.017 in. (0.07 - 0.43 mm.) Flour-sized to sugar-sized

Passing #200 <0.0029 in. (<0.07 mm.) Flour-sized and smaller

DESCRIPTION

Secondary Constituent is Fine Grained

Secondary Constituent is

Coarse Grained

SPT - N60

(# blows / ft)

Soft

Stiff

Very Stiff

Hard

2 - 4

4 - 8

8 - 15

15 - 30

Weakly Crumbles or breaks with handling or slight finger pressure

Crumbles or breaks with considerable finger pressure

UNCONFINED

COMPRESSIVE

STRENGTH (Qu)(psf)

VISUAL / MANUAL CRITERIA

<500

0.5 PP <1

1 PP <2

2 PP <4

4 PP >8000

4000 - 8000

500 - 1000

1000 - 2000

2000 - 4000

Rounded

Subrounded

Dry

Wet Visible free water, usually soil is below water table

Thumb will penetrate more than 1 inch (25 mm).

Extrudes between fingers when squeezed.

Thumb will penetrate soil about 1 inch (25 mm).

Remolded by light finger pressure.

Thumb will penetrate soil about 1/4 inch (6 mm).

Remolded by strong finger pressure.

Can…