Geotechnical Engineering Report titled Squaw Butte Tower Replacements,.pdf

Geotechnical Engineering Report Squaw Butte Tower Replacements

Gem County, Idaho

November 3, 2017

Terracon Project No. 62175084

Prepared for:

Federal Aviation Administration

Renton, Washington

Prepared by:

Terracon Consultants, Inc.

Boise, Idaho mailto:xiao.mei@faa.gov

Squaw Butte Tower Replacements ■ Gem County, Idaho November 3, 2017 ■ Terracon Project No. 62175084

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TABLE OF CONTENTS

Page

EXECUTIVE SUMMARY ............................................................................................................ i

INTRODUCTION

PROJECT INFORMATION

2.1 Project Description

2.2 Site Location and Description

SUBSURFACE CONDITIONS

3.1 Typical Subsurface Profile

3.2 Groundwater

RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

4.2 Earthwork

Site Clearing and Subgrade Preparation

Excavations

Fill Materials and Placement

Grading and Drainage

Earthwork Construction Considerations

4.3 Foundations

Tower Foundation – Shallow Spread Foundation Recommendations

Spread Foundation Construction Considerations

4.4 Seismic Considerations

4.5 Corrosion Considerations

GENERAL COMMENTS

APPENDIX A – FIELD EXPLORATION

Exhibit A-1 Site Location Map Exhibit A-2 Exploration Plan Exhibit A-3 Field Exploration Description Exhibits A-4 to A-7 Boring Logs Exhibits A-8 to A-10 Core Photo Log

APPENDIX B – LABORATORY TESTING

Exhibit B-1 Laboratory Test Description Exhibit B-2 Gradation Test Results Exhibit B-3 Chemical Test Results

APPENDIX C – SUPPORTING DOCUMENTS

Exhibit C-1 General Notes Exhibit C-2 Unified Soil Classification Exhibit C-3 Description of Rock Properties

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EXECUTIVE SUMMARY

A geotechnical exploration has been performed for Squaw Butte Tower Replacement project in

Gem County, Idaho. The following geotechnical considerations were identified:

■ Undocumented fill was encountered to depths of about ½ to 6½ feet, the fill depth should be expected to vary. The fill is not suitable for support of structures and should be removed and replaced with properly compacted Aggregate Base.

■ Basalt rock was encountered at depths of about ½ to 6½ feet below the ground surface in the boring performed at the site. The elevation of basalt rock can vary abruptly in relatively short horizontal distances. The rock was generally highly fractured with very close to close fracture spacing.

The Contractor should be prepared to use blasting, hydraulic or pneumatic breakers, or other methods to assist in rock removal. Care should be taken during the selection of rock excavation methods and during rock removal activities to reduce the potential of damaging existing improvements.

■ The proposed towers may be founded on shallow spread foundations bearing on undisturbed basalt rock or on compacted Aggregate Base that extends to undisturbed basalt rock. A leveling course may be necessary beneath foundations supported directly on rock.

■ Based on the 2012 International Building Code, the seismic site classification for this site is C.

This summary should be used in conjunction with the entire report for design purposes. It should be recognized that details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The General

Comments Section should be read for an understanding of the report limitations.

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GEOTECHNICAL ENGINEERING REPORT

PROPOSED SQUAW BUTTE TOWER REPLACEMENTS

GEM COUNTY, IDAHO

Terracon Project No. 62175084

November 3, 2017

INTRODUCTION

This report presents the results of our geotechnical engineering services performed for the Squaw

Butte Tower Replacements located in Gem County, Idaho. The project location is shown on the

Site Location Map presented in Appendix A (Exhibit A-1).

Our geotechnical engineering services consisted of drilling four borings to determine subsurface conditions, performing laboratory testing on representative soil and rock samples, performing engineering analyses of the subsurface soils, and preparing this report. The purpose of these services is to provide information and/or geotechnical engineering recommendations relative to:

subsurface soil and rock conditions earthwork seismic considerations foundation design and construction groundwater conditions at the time of our field exploration

PROJECT INFORMATION

2.1 Project Description

Our understanding of the project is summarized in the table below.

Item Description1

Proposed improvements Two 30 foot and two 40-foot tall self-support towers. These towers will replace the existing towers at the site.

Below grade areas None

Site retaining walls None

Pavements Exploration and recommendations for pavement design were not included in Terracon’s scope of services.

Stormwater disposal Exploration and recommendations for stormwater management were not included in Terracon’s scope of services.

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Item Description1

1. In the event these details are inconsistent with final design criteria, we should be contacted so that we may update our recommendations as needed.

2.2 Site Location and Description

Item Description

Location

The proposed project will be located at Squaw Butte in Gem

County, Idaho. See the Site Location Map in Appendix A (Exhibit

A-1).

Approximate GPS coordinates of the site are 44.0114⁰/-116.4058⁰

Existing site improvements

The site is developed with four existing towers, an equipment building, and a fuel tank. A concrete jersey barrier and a fence bound the site. Underground utilities were marked throughout the site. The existing towers have guy lines to resist wind loads.

Current ground cover Gravel surfacing

Existing topography The site slopes down to the west.

SUBSURFACE CONDITIONS

Our field exploration consisted of drilling four borings within the project area. A description of our field exploration is presented in Appendix A. Laboratory tests were conducted on selected soil samples obtained during our exploration. A description of the laboratory testing is presented in

Appendix B.

3.1 Typical Subsurface Profile

Specific soil and rock conditions encountered at the boring locations are indicated on the boring logs, which are presented in Appendix A. Stratification boundaries on the logs represent the approximate locations of changes in soil types; in-situ, the transition between materials may be gradual. Based on our borings and laboratory testing, generalized soil and rock conditions for the project site are presented in the following table.

Description Approximate Depth1 to

Bottom of Stratum Material Encountered Consistency/Density

Stratum 1 ½ to 6½ feet Undocumented fill consisting of silty sand with varying amounts of gravel.

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Description Approximate Depth1 to

Bottom of Stratum Material Encountered Consistency/Density

Stratum 2 2½ feet, where encountered

Sandy silt with gravel. Encountered in boring B-1.

Stratum 3

Extended to maximum depth explored of 17½ feet.

Rock. The rock generally consisted of basalt with very close to close fracture spacing. Baked soil zones were encountered in boring B-1 and

B-3 at the bottom of the basalt.

Sandstone was encountered in boring B-3 at a depth of 15 feet

1. Depth below existing ground surface, as encountered in our borings.

3.2 Groundwater

The borings were monitored during drilling for the presence and depth of groundwater.

Groundwater was not encountered within the borings at the time of drilling. Groundwater fluctuations may occur due to seasonal variations in the amount of rainfall, runoff, irrigation and other factors not evident at the time the boring was performed. Evaluations of these factors is beyond the scope of this exploration.

RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

Based on the materials encountered in the borings, it is our opinion that the site is suitable to support the proposed towers on shallow spread foundations, provided the recommendations included in this report are incorporated into project design and construction. Primary geotechnical considerations identified are discussed below.

■ Undocumented fill was encountered to a depth of ½ to 6½ feet, fill depth should be expected to vary. Undocumented fill is not suitable for support of structures and should be removed and replaced with properly compacted Aggregate Base.

■ Basalt rock was encountered at approximately ½ to 6½ feet below the ground surface in the boring performed at the site. The elevation of basalt rock can vary abruptly in relatively short horizontal distances. The rock was generally highly fractured with a very close to close fracture spacing.

Specific conclusions and recommendations regarding these geotechnical considerations, as well as other geotechnical aspects of design and construction are presented in the following sections.

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The recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, and our current understanding of the proposed project.

4.2 Earthwork

The recommendations presented in this report for design and construction of foundations are contingent upon the successful performance of the tasks related to the earthwork recommendations outlined in this section.

Earthwork on the project should be observed and evaluated by Terracon during construction.

Monitoring of earthwork should include removal of unsuitable fill soils, observation and testing of site and subgrade preparation, placement of fill materials, foundation bearing conditions, and other geotechnical conditions exposed during construction of the project.

Site Clearing and Subgrade Preparation

In areas of site grading, if any, deleterious materials such as undocumented fill, vegetation, root systems, topsoil, and soft, frozen, disturbed, or otherwise unsuitable materials should be completely removed from areas that will receive fill prior to construction. Surfaces exposed after excavation should be free of mounds and depressions that could prevent uniform compaction.

After removal of the materials described above is complete, the top 8 inches of the exposed native soils should be scarified, moisture conditioned, and compacted to the requirements outlined in

Section 4.2.2 of this report.

Foundations should be supported directly on undisturbed rock or on compacted Aggregate Base supported on undisturbed rock.

Excavations

As discussed in Section 3.1 of this report, basalt rock was encountered within the borings. The basalt will impact excavation of the foundations. Depending on the depth of the foundations, associated utilities, and buried features, the basalt rock may impact excavations. Based on the explorations at this site and on other experience with basalt in the area, variation in the top of rock elevation can occur abruptly in short horizontal distances.

Local experience indicates that blasting or use of hydraulic or pneumatic breakers will likely be required for rock excavation. The Contractor should be prepared for blasting and/or to utilize hydraulic or pneumatic breakers to assist in rock removal. Blasting to remove relatively small thicknesses of rock can be difficult and inefficient. Care should be taken to avoid overblasting and disturbing rock that is to be left in place.

To help reduce the potential for damage to existing facilities we recommend the following measures be implemented during rock excavation:

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Performance Specification – We recommend that the project specification that addresses rock removal be performance based. The Contractor should be allowed to select the means and methods of rock excavation. The specification should include the requirement that the existing structures, utilities, and facilities in the area not be adversely affected by construction activities and the stipulation that any damage be repaired at the Contractor’s expense. The specification should require that the Contractor submit a rock excavation plan for review. The plan should include the details on how the excavation will be made, what equipment or materials will be used, details on the limits or capabilities of equipment or materials, and how vibrations will be monitored and controlled.

Pre-Bidding Observations - We recommend the existing facility be made available to contractors for observations prior to bidding.

Pre-condition and Post-condition Survey – Prior to commencement of rock excavation activities, a pre-condition survey of the existing facilities within at least 200 feet of any potential rock removal should be performed. The pre-condition survey should include, but not be limited to, photos, general description of the structures or features, and documentation of any existing distress observed. Following completion of rock removal activities, a post-construction survey should be performed to document any changes.

Pre-Rock Excavation Meeting – Prior to commencing rock excavation activities, but after the pre-condition survey has been performed, the Contractor should meet with Engineer of Record. In this meeting the Contractor should present the results of the pre-condition survey, identify areas/features of concern, and present the proposed rock excavation plan.

This plan should include details of equipment and methods that will be used to excavate the rock and to monitor and control vibrations during excavation.

Vibration Monitoring – The Contractor should be responsible for determining allowable particle velocities and ground vibration limits that will not damage the adjacent facilities.

A continuously recording, full-featured vibration monitor should be used to measure ground vibrations. The results of the monitoring should be used to adjust the construction activities, if necessary, to reduce ground vibrations to acceptable levels. If the monitoring indicates the construction method used may be adversely impacting adjacent facilities or if allowable vibration levels are exceeded, other methods of construction should be immediately implemented, and provisions for repairing the impacts should be made by the

Contractor.

Fill Materials and Placement

Fill material requirements vary depending on the intended use of the material. The following table summarizes the fill material designations and the zones where they may be placed.

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Fill Designation Materials Acceptable Location for

Placement

Site Grading Materials

On-site soils may be used as Site Grading

Materials provided they are free of topsoil, vegetation, construction debris, and other deleterious materials.

Non-structure areas.

Aggregate Base

Aggregate Base should meet the requirements for ¾-inch (Type I) crushed aggregate in accordance with ISPWC Section

802.

Below structures.

Fill materials should be placed in horizontal, loose lifts not exceeding 8 inches thick. Fill should be adjusted to within ±2 percent of the optimum moisture content, and compacted to the minimum percentages of either maximum dry density or relative density shown in the following table, whichever is appropriate for the material being used. Each lift of fill should be tested at various locations within the structure footprint to verify it meets the density requirements presented in the following table.

Location

Percent of Maximum

Dry Density, ASTM

D1557

Percent Relative

Density, ASTM

D4253/D4254

Beneath structures 95 80

Other areas of fill and backfill 90 75

Grading and Drainage

All grades must provide effective drainage away from the structures during and after construction.

Runoff and surface pad drainage should be collected and discharged far enough away from the structures to prevent wetting of the foundation soils. Inadequate drainage could result in unacceptable differential movements. Effective drainage should be maintained for the life of the structures.

Earthwork Construction Considerations

The contractor is responsible for designing and constructing stable, temporary excavations as required to maintain stability of both the excavation sides and bottom, and for protecting existing facilities/utilities. Excavations should be sloped or shored in accordance with local, state, and federal regulations, including current OSHA excavation and trench safety standards.

Grading operations should be controlled to prevent water from flowing into construction areas.

Excessive wetting or drying of the subgrade soils should be avoided during construction. Excess water should be promptly removed.

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Soils exposed during construction will be susceptible to rutting or pumping under construction traffic when wet. Measures that may help reduce disturbance of exposed soils include performing earthwork during warm, dry weather, the use of light track-mounted equipment, and avoidance of heavy repeated traffic over a given area.

4.3 Foundations

Design recommendations and construction considerations for structure foundations are presented in the following subsections.

Tower Foundation – Shallow Spread Foundation Recommendations

From a geotechnical standpoint, the proposed towers can be supported on a shallow spread foundations. The foundations should be supported directly on the basalt rock. Design recommendations for the tower foundations are presented in the following table.

Description Criteria

Foundation type Shallow spread foundations.

Bearing material

Undisturbed basalt rock or compacted Aggregate

Base meeting the requirements of Section 4.2.2 of this report. The Aggregate Base should extend to undisturbed basalt rock.

Net allowable bearing pressure 6,000 psf1

Minimum embedment depth below lowest adjacent permanent finished grade 36 inches (for frost protection)

Estimated settlement Total: 1 inch or less

Differential: Typically ½ to ¾ of the total settlement

Ultimate coefficient of friction to resist sliding2

0.5 2 (An appropriate factor of safety should be applied to this value for use in design.)

Ultimate passive equivalent fluid pressure for backfill consisting of compacted

Aggregate Base2

340 pcf 2 (An appropriate factor of safety should be applied to this value for use in design.)

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Description Criteria

Uplift resistance

Ultimate uplift resistance is limited to the effective weight of the foundation and tower plus the effective weight of any soil backfill directly above the foundation.

An appropriate factor of safety should be used in uplift calculations. Backfill above the foundations should meet the requirements presented in Section 4.2 of the project geotechnical report. Resistance to uplift may be evaluated using a unit weight of 90 pcf for backfill soils. Soil weight should be ignored in potential zones of disturbance and in areas where erosion control measures are not used or soil might otherwise be removed.

1. The allowable bearing capacity may be increased by 1/3 for support of temporary loads such as those generated by wind and seismic events.

2. If passive pressure and frictional resistance are considered together, the passive pressure should be reduced by one half. This is because lateral movement of the foundation is required to engage passive pressure.

Spread Foundation Construction Considerations

The rock surface should be cleaned of soil, as well as highly weathered, broken, and loosened rock.

Material meeting the ISPWC requirements for flowable fill or Class 1500 concrete may be used as a leveling course beneath the foundations.

If Aggregate Base is placed beneath foundations, the Aggregate Base layer should extend laterally from the foundation edges a minimum distance equal to 2/3 of the depth of the compacted fill below the footing base elevation, as shown in the adjacent figure.

The base of all foundation excavations should be free of water. Should the soils at bearing level become excessively dry, disturbed, saturated, or frozen, the affected soil should be removed prior to placing concrete.

Terracon should evaluate exposed foundation subgrade conditions during construction prior to placing flowable fill, Aggregate Base, or concrete.

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4.4 Seismic Considerations

IBC1 Seismic Design Parameters

Description Value

Site classification2 C

Ss, Short period spectral response acceleration (Site Class B)3 0.43g (for Site Class B)

S1, 1-second period spectral response acceleration (Site Class B)3 0.14g (for Site Class B)

1. Based on Section 1613 of the 2012 International Building Code (IBC).

2. Based on the 2012 IBC, the seismic site class is determined from a soil profile extending to a depth of

100 feet. The current scope requested did not include a boring to a depth of 100 feet. The boring for this project extended to a depth of approximately 17½ feet. The above classification is based on the assumption that rock similar to that encountered in the lower portion of the borings continue to a depth of at least 100 feet. If desired, a geophysical exploration could be performed to confirm the site classification.

3. Accelerations shown above should be adjusted as required by the IBC to account for the Site

Classification.

4.5 Corrosion Considerations

Tests were performed on samples of near surface soil to provide an indication of the potential of the soils to corrode metal or degrade concrete. Results of the tests are summarized in Appendix

B. We recommend that the design engineers consult with the manufacturers of specific products to determine the need for corrosion protection of buried metal pipes. Based on the results of the sulfate content tests, it is our opinion that Type I cement is suitable for this project.

GENERAL COMMENTS

Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction, and other earth-related construction phases of the project.

The analysis and recommendations presented in this report are based upon the data obtained from the boring performed at the indicated location and from other information discussed in this report. This report does not reflect variations that may occur beyond the boring location, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we

Responsive ■ Resourceful ■ Reliable 10 should be immediately notified so that further evaluation and supplemental recommendations can be provided.

The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, and bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

APPENDIX A

FIELD EXPLORATION

SITE LOCATION

Squaw Butte Tower Replacement Gem County, ID

TOPOGRAPHIC MAP IMAGE COURTESY OF THE U.S. GEOLOGICAL SURVEY

QUADRANGLES INCLUDE: SQUAW BUTTE, ID (1/1/1970) and NORTHEAST EMMETT, ID (1/1/1985).

11849 W Executive Dr Ste G

Boise, ID 83713-1944

62175084 Project Manager:

Drawn by:

Checked by:

Approved by:

LJM

MJD

MJD

1”=2,000’

62175084

10/24/2017

Project No.

Scale:

File Name:

Date:

A-1

Exhibit

MJD

SITE

B-1

B-2

EXPLORATION PLAN

Squaw Butte Tower Replacement Gem County, ID

11849 W Executive Dr Ste G

Boise, ID 83713-1944

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

62175084

AERIAL PHOTOGRAPHY PROVIDED

BY GOOGLE EARTH PRO

LJM

MJD

MJD

NOT TO SCALE

62175084

10/24/2017

Scale:

A-2

Exhibit

B-3

Project Manager:

Drawn by:

Checked by:

Approved by:

Project No.

File Name:

Date:

MJD

B-4

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Field Exploration Description

The subsurface exploration consisted of drilling four borings in the project area. The approximate locations of the explorations are shown on the Exploration Plan, Exhibit A-2 included in this appendix. The borings were drilled to depths of about 10 to 17½ feet below the existing ground surface with a truck-mounted drill rig using a combination of continuous-flight hollow-stem augers and rock coring equipment. A Terracon field engineer recorded logs of the borings during the drilling operations. The boring logs are presented in this appendix. General Notes for interpretation of the boring logs, a summary of the Unified Soil Classification System (USCS), and a Description of Rock Properties are presented in Appendix C.

The boring locations were selected by the FAA based on the proposed tower locations and locations of existing utilities. Terracon recorded the locations in the field using a handheld GPS device having an accuracy typically within about 20 feet. The approximate ground-surface elevations at the boring locations are interpolated from the contours of a topographic site plan provided by the FAA. The locations and elevations of the borings should be considered accurate only to the degree implied by the means and methods used to define them.

Disturbed soil samples were obtained at various depths in the borings using a 2-inch-outside-diameter split-spoon sampler driven in general accordance with the Standard Penetration

Test (SPT). The result of the SPT is an N-value. The N-value is the number of blows from a 140-pound hammer falling from a height of 30 inches that are required to drive the split-spoon sampler the last 12 inches of an 18-inch interval (or the distance indicated). N-values are shown on the boring logs.

The N-value provides a reasonable estimate of the relative in-place density of non-cemented sandy type materials. However, the N-value only provides an indication of the relative stiffness of cohesive materials, since the penetration resistance of these soils may be affected by the moisture content. Considerable care must be exercised in interpreting the N-value in gravelly soils, particularly where the size of the gravel particles exceeds the inside diameter of the sampling spoon.

An automatic SPT hammer was used to advance the split-spoon sampler in the borings performed on this site. A greater efficiency is typically achieved with the automatic hammer compared to the conventional safety hammer operated with a cathead and rope. Published correlations between the SPT values and soil properties are based on the cathead and rope method. The higher efficiency of the automatic hammer affects the standard penetration resistance blow count (N-value) by increasing the penetration per hammer blow over what would be obtained using the cathead and rope method. The effect of the automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report.

Characteristics of the rock core samples were recorded, including percent recovery, Rock Quality

Designation (RQD), and a description of the rock materials recovered from each core run. RQD is the cumulative length of core pieces that are 4 inches and longer expressed as a percentage of the length of core run. RQD and percent recovery are presented on the boring logs in Appendix A.

5855+/-

5854.5+/-

5842+/-

3-13-49 N=62

50/2"

1.2

0.2

2.9

3.1

2.5

2.0

2.5

15.0

FILL - SILTY SAND WITH GRAVEL , grey to brown

SANDY SILT WITH GRAVEL (ML), grey BASALT, grey, very close to close fracture spacing, slightly weathered

BAKED SOIL ZONE, rust brown, close fracture spacing, slightly weathered, silt/clay/sand soils subject to contact metamorphism during basalt flow placement, iron staining Boring Terminated at 15 Feet

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

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IN

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L O

G

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N O

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1/

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T pc f)

ELEVATION (Ft.)

Approximate Surface Elev: 5857 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

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F t.)

R O

C K

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C O

V E

R Y

Gem County, ID

SITE:

Advancement Method:

Hollow stem auger, HQ diamond bit rock coring equipment

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 62175084

Drill Rig: CME 75

Boring Started: 09-13-2017

BORING LOG NO. B-1

Federal Aviation AdministrationCLIENT:

Renton, WA

Driller: Haztech Drilling, Inc.

Boring Completed: 09-13-2017

Exhibit: A-4

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevations interpolated from topographic site plan

PROJECT: Squaw Butte Tower Replacement

11849 W Executive Dr Ste G Boise, ID

Not encountered

WATER LEVEL OBSERVATIONS

DEPTH

LOCATION See Exhibit A-2

Latitude: 44.011423° Longitude: -116.405905°

R Q

D

5865.5+/-

5855.5+/-

2.6

3.6

0.5

10.5

FILL - SILTY SAND WITH GRAVEL , brown BASALT, grey, very close to close fracture spacing, slightly weathered

Boring Terminated at 10.5 Feet

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

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P A

R A

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D F

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M O

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IG

IN

A

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-N O

W E

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Q U

A W

B U

T T

E T

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.G P

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A T

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P

LA

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.G D

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1/

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D C

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IV

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H ps f)

P E

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W A

T E

R C

O N

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N T

D R

Y U

N

IT

W E

IG

H

T pc f)

ELEVATION (Ft.)

Approximate Surface Elev: 5866 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

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E

F

IE

LD

T

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T R

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U

LT

S

R E

C O

V E

R Y

F t.)

R O

C K

R E

C O

V E

R Y

Gem County, ID

SITE:

Advancement Method:

Hollow stem auger, HQ diamond bit rock coring equipment

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 62175084

Drill Rig: CME 75

Boring Started: 09-13-2017

BORING LOG NO. B-2

Federal Aviation AdministrationCLIENT:

Renton, WA

Driller: Haztech Drilling, Inc.

Boring Completed: 09-13-2017

Exhibit: A-5

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevations interpolated from topographic site plan

PROJECT: Squaw Butte Tower Replacement

11849 W Executive Dr Ste G Boise, ID

Not encountered

WATER LEVEL OBSERVATIONS

DEPTH

LOCATION See Exhibit A-2

Latitude: 44.011512° Longitude: -116.405601°

R Q

D

10550

5852.5+/-

5845.5+/-

5844+/-

5841.5+/-

7-9-7 N=16

9-18-25 N=43

34-46-50 N=96

0.5

1.4

1.3

1.5

2.2

0.8

1.8

6.5

13.5

15.0

17.5

FILL - SILTY SAND , trace to with gravel, light brown

BASALT, grey to black, very close to close fracture spacing, slightly weathered

BAKED SOIL ZONE, rust brown, extremely close fracture spacing, moderately weathered, silt/clay/sand soils subject to contact metamorphism during basalt flow placement, iron staining SILTY SANDSTONE, brown, close fracture spacing, slightly to moderately weathered

Boring Terminated at 17.5 Feet

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

O

S M

A R

T L

O G

-N O

W E

LL

S

Q U

A W

B U

T T

E T

O W

E R

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

1/

/1

U N

C O

N F

IN

E

D C

O M

P R

E S

S

IV

E S

T R

E N

G T

H ps f)

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

ELEVATION (Ft.)

Approximate Surface Elev: 5859 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

Y P

E

F

IE

LD

T

E S

T R

E S

U

LT

S

R E

C O

V E

R Y

F t.)

R O

C K

R E

C O

V E

R Y

Gem County, ID

SITE:

Advancement Method:

Hollow stem auger, HQ diamond bit rock coring equipment

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 62175084

Drill Rig: CME 75

Boring Started: 09-13-2017

BORING LOG NO. B-3

Federal Aviation AdministrationCLIENT:

Renton, WA

Driller: Haztech Drilling, Inc.

Boring Completed: 09-13-2017

Exhibit: A-6

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevations interpolated from topographic site plan

PROJECT: Squaw Butte Tower Replacement

11849 W Executive Dr Ste G Boise, ID

Not encountered

WATER LEVEL OBSERVATIONS

DEPTH

LOCATION See Exhibit A-2

Latitude: 44.011386° Longitude: -116.405874°

R Q

D

5865.5+/-

5856+/-

31-50/4"0.7

2.5

2.2

0.5

10.0

FILL - SILTY SAND WITH GRAVEL , brown BASALT, grey, very close to close fracture spacing, slightly weathered

Boring Terminated at 10 Feet

G R

A P

H

IC

L O

G

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

O

S M

A R

T L

O G

-N O

W E

LL

S

Q U

A W

B U

T T

E T

O W

E R

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

1/

/1

U N

C O

N F

IN

E

D C

O M

P R

E S

S

IV

E S

T R

E N

G T

H ps f)

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

ELEVATION (Ft.)

Approximate Surface Elev: 5866 (Ft.) +/-

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

S A

M P

LE

T

Y P

E

F

IE

LD

T

E S

T R

E S

U

LT

S

R E

C O

V E

R Y

F t.)

R O

C K

R E

C O

V E

R Y

Gem County, ID

SITE:

Advancement Method:

Hollow stem auger, HQ diamond bit rock coring equipment

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 62175084

Drill Rig: CME 75

Boring Started: 09-13-2017

BORING LOG NO. B-4

Federal Aviation AdministrationCLIENT:

Renton, WA

Driller: Haztech Drilling, Inc.

Boring Completed: 09-13-2017

Exhibit: A-7

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

Elevations interpolated from topographic site plan

PROJECT: Squaw Butte Tower Replacement

11849 W Executive Dr Ste G Boise, ID

Not encountered

WATER LEVEL OBSERVATIONS

DEPTH

LOCATION See Exhibit A-2

Latitude: 44.011362° Longitude: -116.405651°

R Q

D

Core Photo Log ■ Gem County, Idaho 11/1/2017 ■ Terracon Project No. 62175084

B-1, 5.0-12.5 feet

B-1, 12.5-15.0 feet

Exhibit A-8

B-2, 0.5-10.5 feet

B-3, 6.5-17.5 feet

Exhibit A-9

B-4, 0.0-8.7 feet

B-4, 8.7-10.0 feet

Exhibit A-10

APPENDIX B

LABORATORY TESTING

Reliable ■ Resourceful ■ Responsive Exhibit B-1

Laboratory Test Description

Samples obtained during the field exploration were transferred to the laboratory and were visually classified in general accordance with the Unified Soil Classification System and Description of

Rock Properties described in Appendix C. Representative samples were selected for testing to determine physical and engineering properties of the subsurface materials. Following are the laboratory tests conducted and a brief description of the purpose of each test:

Test Conducted To Determine:

Moisture content Moisture content of the sample.

Gradation Particle size analysis of the sample.

Soluble sulfate Soluble sulfate content of the sample.

Chlorides Chloride content of the sample.

pH pH of the sample.

Resistivity Electrical resistance of the sample. For use in determining corrosivity of soil.

Unconfined compressive strength Unconfined compressive strength of a relatively undisturbed sample of intact rock.

The tests were performed in general accordance with the respective ASTM standards. These standards are a reference to general methodology. In some cases, variations to methods are applied as a result of local practice or professional judgment. Results of the laboratory tests are generally summarized on the boring logs in Appendix A. Gradation test results are presented in

Exhibit B-2 of this appendix. Results of the corrosion potential tests are summarized in Exhibit B-

3 of this appendix.

0.0010.010.1110100

30 40 501.5 2006 810 1441 3/4 1/2 60

GRAIN SIZE IN MILLIMETERS

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

H T

HYDROMETERU.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS

4 3/8 3 100 1403 2

GRAIN SIZE DISTRIBUTION

ASTM D422 / ASTM C136

6 16 20

PROJECT NUMBER: 62175084

PROJECT: Squaw Butte Tower Replacement

SITE:

Gem County, ID

CLIENT: Federal Aviation Administration Renton, WA

EXHIBIT: B-2

11849 W Executive Dr Ste G

Boise, ID

LA

B

O R

A T

O R

Y T

E S

T S

A R

E N

O T

V A

LI

D

IF

S

E P

A R

A T

E D

F R

O M

O R

IG

IN

A L

R E

P O

R

R

A

IN

S

IZ

E : U

S C

S -2

S

Q U

A W

B U

T T

E T

O W

E R

.G P

J T

E R

R A

C O

N _D

A T

A T

E M

P

LA

T E

.G D

T

1/

/1

38.5

7.1

12.5

4.459

0.23

0.749

B-2

B-3

LL PL PI

finefine

SILT OR CLAY

%Sand%Gravel

COBBLES

GRAVEL SAND

coarse medium

%Clay

15.4

36.5

%Silt %Fines

SILTY SAND with GRAVEL (SM)

SILTY SAND (SM)

USCS Classification

WC (%)

0 - 1.5

2.5 - 4

Boring ID Depth

Boring ID Depth

D60

46.1

56.4

0 - 1.5

2.5 - 4

D10D30

CuCc

D100 coarse

B-3

Project Number:

Service Date:

Report Date:

Task:

Client

Date Received:

0-1.5

8.28

Analyzed By:

The tests were performed in general accordance with applicable ASTM, AASHTO, or DOT test methods. This report is exclusively for the use of the client indicated above and shall not be reproduced except in full without the written consent of our company. Test results transmitted herein are only applicable to the actual samples tested at the location(s) referenced and are not necessarily indicative of the properties of other apparently similar or identical materials.

62175084

Terracon (62)Sample Submitted By: 9/21/2017

Results of Resistivity Analysis

Chemist

09/26/17

Lab No: 17-0988

Sample Number

Sample Location

Sample Depth (ft.)

10/03/17

750 Pilot Road, Suite F

Las Vegas, Nevada 89119

(702) 597-9393

Project

CHEMICAL LABORATORY TEST REPORT

Trisha Campo pH Analysis, AWWA 4500 H

Water Soluble Sulfate (SO4), ASTM D 516 (mg/kg)

Chlorides, ASTM D 512 (mg/kg)

Resistivity, ASTM G 57 (ohm-cm)

Squaw Butte Tower Replacement

APPENDIX C

SUPPORTING DOCUMENTS

Exhibit: C-1

Unconfined Compressive Strength Qu, (psf)

500 to 1,000

2,000 to 4,000

4,000 to 8,000

1,000 to 2,000 less than 500

> 8,000

Auger Cuttings Rock Core

Standard Penetration Test

Non-plastic Low Medium High

DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

GENERAL NOTES

Over 12 in. (300 mm) 12 in. to 3 in. (300mm to 75mm) 3 in. to #4 sieve (75mm to 4.75 mm) #4 to #200 sieve (4.75mm to 0.075mm Passing #200 sieve (0.075mm)

Particle Size

< 5 5 - 12 > 12

Percent of Dry Weight

Descriptive Term(s) of other constituents

RELATIVE PROPORTIONS OF FINES

1 - 10 11 - 30

> 30

Plasticity Index

Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.

LOCATION AND ELEVATION NOTES

Percent of Dry Weight

Major Component of Sample

Trace With Modifier

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY

Trace With Modifier

DESCRIPTIVE SOIL CLASSIFICATION

Boulders Cobbles Gravel Sand Silt or Clay

Descriptive Term(s) of other constituents

< 15 15 - 29 > 30

Term

PLASTICITY DESCRIPTION

Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated.

Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations.

Water Level After a Specified Period of Time

Water Level After a Specified Period of Time

Water Initially Encountered

Standard Penetration Test Resistance (Blows/Ft.)

Hand Penetrometer

Torvane

Dynamic Cone Penetrometer

Photo-Ionization Detector

Organic Vapor Analyzer

Unless otherwise noted, Latitude and Longitude are approximately determined using a hand-held GPS device. The accuracy of such devices is variable. Surface elevation data annotated with +/- indicates that no actual topographical survey was conducted to confirm the surface elevation. Instead, the surface elevation was approximately determined from topographic maps of the area.

N

(HP)

(T)

(DCP)

(PID)

(OVA)

F

IE

L D

T E

S T

S

W A

T E

R L

E V

E L

S A

M P

L

IN

G S

T R

E N

G T

H T

E R

M S Standard Penetration or

N-Value Blows/Ft.

Descriptive Term (Consistency)

Descriptive Term (Density)

CONSISTENCY OF FINE-GRAINED SOILS

(50% or more passing the No. 200 sieve.)

Consistency determined by laboratory shear strength testing, field visual-manual procedures or standard penetration resistance

Standard Penetration or N-Value

Blows/Ft.

(More than 50% retained on No. 200 sieve.)

Density determined by Standard Penetration Resistance

RELATIVE DENSITY OF COARSE-GRAINED SOILS

Hard > 30

> 50 15 - 30Very Stiff

Stiff

Medium Stiff

Very Soft 0 - 1

Medium Dense

SoftLoose

Very Dense

8 - 1530 - 50Dense

4 - 810 - 29

2 - 44 - 9

Very Loose 0 - 3

UNIFIED SOIL CLASSIFICATION SYSTEM

Criteria for Assigning Group Symbols and Group Names Using Laboratory Tests A Soil Classification

Group Symbol

Group Name B

Coarse Grained Soils:

More than 50% retained on No. 200 sieve

Gravels:

More than 50% of coarse fraction retained on No. 4 sieve

Clean Gravels:

Less than 5% fines C

Cu 4 and 1 Cc 3 E GW Well-graded gravel F Cu 4 and/or 1 Cc 3 E GP Poorly graded gravel F

Gravels with Fines:

More than 12% fines C

Fines classify as ML or MH GM Silty gravel F,G,H Fines classify as CL or CH GC Clayey gravel F,G,H

Sands:

50% or more of coarse fraction passes No. 4 sieve

Clean Sands:

Less than 5% fines D

Cu 6 and 1 Cc 3 E SW Well-graded sand I Cu 6 and/or 1 Cc 3 E SP Poorly graded sand I

Sands with Fines:

More than 12% fines D

Fines classify as ML or MH SM Silty sand G,H,I Fines classify as CL or CH SC Clayey sand G,H,I

Fine-Grained Soils:

50% or more passes the No. 200 sieve

Silts and Clays:

Liquid limit less than 50

Inorganic:

PI 7 and plots on or above “A” line J CL Lean clay K,L,M PI 4 or plots below “A” line J ML Silt K,L,M

Organic:

Liquid limit - oven dried

0.75 OL

Organic clay K,L,M,N

Liquid limit - not dried Organic silt K,L,M,O

Silts and Clays:

Liquid limit 50 or more

Inorganic:

PI plots on or above “A” line CH Fat clay K,L,M PI plots below “A” line MH Elastic Silt K,L,M

Organic:

Liquid limit - oven dried

0.75 OH

Organic clay K,L,M,P

Liquid limit - not dried Organic silt K,L,M,Q Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-inch (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name.

C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay

E Cu = D60/D10 Cc =

DxD

)(D

F If soil contains 15% sand, add “with sand” to group name.

G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

H If fines are organic, add “with organic fines” to group name.

I If soil contains 15% gravel, add “with gravel” to group name.

J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay.

K If soil contains 15 to 29% plus No. 200, add “with sand” or “with gravel,” whichever is predominant.

L If soil contains 30% plus No. 200 predominantly sand, add “sandy” to group name.

M If soil contains 30% plus No. 200, predominantly gravel, add

“gravelly” to group name.

N PI 4 and plots on or above “A” line.

O PI 4 or plots below “A” line.

P PI plots on or above “A” line.

Q PI plots below “A” line.

Exhibit C-2

DESCRIPTION OF ROCK PROPERTIES

Exhibit C-3

WEATHERING

Fresh Rock fresh, crystals bright, few joints may show slight staining. Rock rings under hammer if crystalline.

Very slight Rock generally fresh, joi nts stained, some joints may show thin clay coatings, crystals in br oken face show bright. Rock rings under hammer if crystalline.

Slight Rock generally fresh, joints stained, and discoloration extends into rock up to 1 in. Joints may contain clay. In granitoid rocks some occasional feldspar crystals are dull and discolored. Crystalline rocks ring under hammer.

Moderate Significant portions of rock show discoloration and weathering effects. In granitoid rocks, most feldspars are dull and discolored; some show clayey. Rock has dull sound under hammer and shows significant loss of strength as compared with fresh rock.

Moderately severe All rock e xcept quartz discol ored or stain ed. In granitoid r ocks, all felds pars dull and discolored and majority show kaolinization. Rock shows severe loss of strength and can be excavated with geologist’s pick.

Severe All rock except quartz discolored or stained. Rock “fabric” clear and evident, but reduced in strength to strong soil. In granitoid rocks, all feldspars kaolinized to some extent. Some fragments of strong rock usually left.

Very severe All rock except quartz discolored or stained. Rock “fabric” discernible, but mass effectively reduced to “soil” with only fragments of strong rock remaining.

Complete Rock reduced to ”soil”. Rock “fabric” not discernible or discernible only in small, scattered locations. Quartz may be present as dikes or stringers.

HARDNESS (for engineering description of rock – not to be confused with Moh’s scale for minerals)

Very hard Cannot be scratched with knife or sharp pick. Breaking of hand specimens requires several hard blows of geologist’s pick.

Hard Can be scratched with knife or pick only with difficulty. Hard blow of hammer required to detach hand specimen.

Moderately hard Can be scratched with knife or pick. Gouges or grooves to ¼ in. deep can be excavated by hard blow of point of a geologist’s pick. Hand specimens can be detached by moderate blow.

Medium Can be grooved or gouged 1/16 in. deep by firm pressure on knife or pick point. Can be excavated in small chips to pieces about 1-in. maximum size by hard blows of the point of a geologist’s pick.

Soft Can be gouged or grooved readily with knife or pick point. Can be excavated in chips to pieces several inches in size by moderate blows of a pick point. Small thin pieces can be broken by finger pressure.

Very soft Can be carved with knife. Can be excavated readily with point of pick. Pieces 1-in. or more in thickness can be broken with finger pressure. Can be scratched readily by fingernail.

Joint, Bedding, and Foliation Spacing in Rock a

Spacing Joints Bedding/Foliation

Less than 2 in. Very close Very thin 2 in. – 1 ft. Close Thin 1 ft. – 3 ft. Moderately close Medium

3 ft. – 10 ft. Wide Thick More than 10 ft. Very wide Very thick

a. Spacing refers to the distance normal to the planes, of the described feature, which are parallel to each other or nearly so.

Rock Quality Designator (RQD) a Joint Openness Descriptors

RQD, as a percentage Diagnostic description Openness Descriptor

Exceeding 90 Excellent No Visible Separation Tight 90 – 75 Good Less than 1/32 in. Slightly Open 75 – 50 Fair 1/32 to 1/8 in. Moderately Open 50 – 25 Poor 1/8 to 3/8 in. Open

Less than 25 Very poor 3/8 in. to 0.1 ft. Moderately Wide

a. RQD (given as a percentage) = length of core in pieces Greater than 0.1 ft. Wide

4 in. and longer/length of run.

References: American Society of Civil Engineers. Manuals and Reports on En gineering Practice - No. 56. Subsurface Investigation for

Design and Co nstruction of Fo undations of Buildings. New York: American Society of Civil Engineers, 1976. U.S.

Department of the Interior, Bureau of Reclamation, Engineering Geology Field Manual.