3_HVO_Soils_Report_0001.pdf

REPORT

SOILS INVESTIGATION

PROPOSED SELF-SUPPORTING TOWER

HAWAII VOLCANO OBSERVATORY

KILAUEA, HAWAII

for

PACIFIC WIRELESS COMMUNICATIONS, LLC

Project No. 11-0006 February 10, 2011

SHINSATO ENGINEERING, INC.

98-747 KUAHAO PLACE, #E

PEARL CITY, HI 96782

Shinsato Engineering, Inc.

Consulting Geotechnical Engineers

98-747 KUAHAO PLACE, SUITE E

PEARL CITY, HAWAII 96782

PHONE: (808) 487-7855

FAX: (808) 487-7854

February 10, 2011 Project No. 11-0006

Pacific Wireless Communications, LLC Attention: Mr. Jeffrey Oh 710 Kakoi Street Honolulu, Hawaii 96819

Gentlemen:

The attached report presents the results of a soils investigation for the proposed 40-foot high self-supporting tower to be constructed at the Hawaii Volcano Observatory in Kilauea, Hawaii.

A summary of the findings is as follows:

1) The subsurface condition for the site was explored by drilling 1 test boring to a depth of 15 feet below existing grade. The boring encountered dense, gray-brown silty GRAVEL to a depth of 3 inches followed by moderately hard to hard BASALTIC ROCK to a depth of 7 feet. An 11-inch thick void was found in the BASALT formation from 16 to 27 inches below grade. Beneath the BASALT, dense to medium dense CLINKERS was found from 7 to 13.33 feet then by medium hard to hard BASALT to the final depth of the boring at 15 feet. Groundwater was not encountered in the boring at the time of the field investigation.

2) Special considerations are anticipated for the design and construction of the project due to the existing subsurface conditions. These include but may not be limited to the following:

a) The test boring encountered an 11-inch thick void at 16 inches below grade. The lateral extent of the void is unknown. During construction, it is recommended that probing and grouting be done under the proposed tower foundation. The recommended minimum depth of the probing is 10 feet below the bottom of the tower foundation. Probes (minimum 3-inch diameter) shall be made at the corners of the foundation and one at the center. The probe holes and any voids that are encountered shall be filled with a cementitious slurry (typically 7 gallons of water per sack of cement).

b) Excavations into the underlying BASALT may be difficult to accomplish and will likely require heavy equipment for removal.

3) Based on the findings and observations of this investigation, it is concluded that the proposed tower may be supported on either a concrete mat foundation or cast-in-place piers (caissons).

4) A summary of the foundation design parameters is as follows:

a) Allowable bearing pressure:

Mat foundation: 50,000 psf bearing on the underlying BASALT;

4,000 psf bearing on compacted granular soil (minimum embedment of 24-inches below the lowest adjacent finished grade)

Pacific Wireless Communications, LLC February 10, 2011 Page Two

Caissons: 50,000 psf for end-bearing and 1,000 pounds per square foot of sidewall area for skin-friction.

b) Allowable frictional coefficient: 0.70 times dead load

c) Allowable lateral earth pressure coefficients:

Passive: 4.60 Active: 0.22 At-rest: 0.36

d) Unit weight of soil: 130 pcf on-site soil 140 pcf imported structural fill 150 pcf underlying BASALTIC ROCK

e) Site Class (2003 IBC): B: Rock profile

Details of the findings and recommendations are presented in the attached report.

This investigation was made in accordance with generally accepted engineering procedures and included such field and laboratory tests considered necessary for the project. In the opinion of the undersigned, the accompanying report has been substantiated by mathematical data in conformity with generally accepted engineering principles and presents fairly the design information requested by your organization. No other warranty is either expressed or given.

Respectfully submitted, SHINSATO ENGINEERING, INC.

Lawrence S. Shinsato, P.E.

President

This work was prepared by me LSS:ls or under my supervision.

License Expires 04/30/12

TABLE OF CONTENTS

Page

INTRODUCTION --------------------------------------------------------------------- 1

SCOPE OF WORK --------------------------------------------------------------------- 1

PLANNED DEVELOPMENT ----------------------------------------------------------- 1

SITE CONDITIONS ---------------------------------------------------------------------- 1 Surface ---------------------------------------------------------------------- 1 Subsurface ---------------------------------------------------------------------- 2 Geology ---------------------------------------------------------------------- 2

CONCLUSIONS AND RECOMMENDATIONS -------------------------------------- 3

General ------------------------------------------------------------------------------- 3 Special Considerations ---------------------------------------------------------- 3 Foundation Design Parameters ---------------------------------------------- 3 Site Class Definition ----------------------------------------------------------- 4 Settlement ---------------------------------------------------------------------- 4 Lateral Earth Pressures and Frictional Resistance ---------------- 5 Slab-on-Grade ---------------------------------------------------------------------- 5 Slopes --------------------------------------------------------------------------------- 5 Site Preparation and Grading ------------------------------------------------- 6

INSPECTION --------------------------------------------------------------------------------- 9

REMARKS --------------------------------------------------------------------------------- 9

APPENDIX

Field Investigation Laboratory Testing Vicinity Map Plot Plan Log of Boring Results of Laboratory Tests

INTRODUCTION

This investigation was made for the purpose of obtaining information on the subsurface conditions from which to base recommendations for foundation design for the proposed 40-foot high self-supporting tower to be constructed at the Hawaii Volcano Observatory in Kilauea, Hawaii. The location of the site, relative to the existing streets and landmarks, is shown on the Vicinity Map, Plate 1.

SCOPE OF WORK

The services included drilling 1 test boring to a depth of 15 feet below existing grade, obtaining samples of the underlying soils, performing laboratory tests to determine pertinent engineering properties of the representative soil samples, and performing an engineering analysis to determine foundation design parameters. The following information is provided for use by the Architect and/or Engineer:

1. General subsurface conditions, as disclosed by the test boring.

2. Physical characteristics of the soils encountered.

3. Recommendations for foundation design, including bearing values, embedment depth and estimated settlement.

4. Recommendations for placement of fill and backfill.

5. Special design considerations.

PLANNED DEVELOPMENT

From the information provided, the project will consist of constructing a new 40-foot high, four-legged self-supporting tower. The tower will have a 7-foot square base.

SITE CONDITIONS

Surface

The site is located in the Hawaii Volcano Observatory property on the northwest side of the Kilauea Crater.

At the time of the investigation, the area was covered by bare gravel. There is a shelter building and a

-2-water tank to the west and southwest side of the proposed tower location.

Subsurface

The subsurface condition for the site was explored by drilling 1 test boring to a depth of 15 feet below existing grade. The location of the boring is shown on the Plot Plan, Plate 2. A detailed log of the boring is presented in the Appendix to this report.

The boring encountered dense, gray-brown silty GRAVEL to a depth of 3 inches followed by moderately hard to hard BASALTIC ROCK to a depth of 7 feet. An 11-inch thick void was found in the BASALT formation from

16 to 27 inches below grade. Beneath the BASALT, dense to medium dense CLINKERS was found from 7 to 13.33 feet then by medium hard to hard BASALT to the final depth of the boring at 15 feet. Groundwater was not encountered in the boring at the time of the field investigation.

From the USDA Soil Conservation Service, "Soil Survey of the Island of Hawaii, State of Hawaii, 1973", the site is located in an area designated as Kilauea extremely gravelly sand, 6 to 12 percent slopes (rKUC). The

Kilauea series consists of somewhat excessively drained gravelly sand that formed in volcanic ash, pumice, and cinders (USDA, 1973, Plate 136, pp. 30).

Geology

The island of Hawaii was built by five volcanoes: Mauna Loa, Kilauea, Hualalai, Mauna Kea and Kohala. The site is located on the northwesterly flank of the Kilauea caldera which is an asymmetrical shield-shaped dome.

The rocks of Kilauea are divided into the older Hilina Volcanic Series and the younger Puna Volcanic Series.

Both series consist of pahoehoe and aa lava flows and associated cinder and spatter cones and ash deposits

(MacDonald, 1971).

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CONCLUSIONS AND RECOMMENDATIONS

General

Based on the findings and observations of this investigation, it is concluded that the proposed tower may be supported on either a concrete mat foundation or cast-in-place piers (caissons).

Special Considerations

Special considerations are anticipated for the design and construction of the project due to the existing subsurface conditions. These include but may not be limited to the following:

a) The test boring encountered an 11-inch thick void at 16 inches below grade. The lateral extent of the void is unknown. During construction, it is recommended that probing and grouting be done under the proposed tower foundation. The recommended minimum depth of the probing is 10 feet below the bottom of the tower foundation. Probes (minimum 3-inch diameter) shall be made at the corners of the foundation and one at the center. The probe holes and any voids that are encountered shall be filled with a cementitious slurry (typically 7 gallons of water per sack of cement).

b) Excavations into the underlying BASALT may be difficult to accomplish and will likely require heavy equipment for removal.

Foundation Design Parameters

The recommended allowable bearing values are as follows:

a) Mat foundation: 50,000 psf bearing on the underlying BASALT.

4,000 psf bearing on compacted granular soil (minimum embedment of 24-inches below the lowest adjacent finished grade).

b) Caissons: 50,000 psf for end-bearing and 1,000 pounds per square foot of sidewall area for skin-friction.

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The bearing values are for dead plus live loads and may be increased by one-third for momentary loads due to wind or seismic forces. If any footing is eccentrically loaded, the maximum edge pressure shall not exceed the bearing pressure for permanent or for momentary loads.

For footings located adjacent to utility trenches, the bottom of the footing shall be deepened below a 1 horizontal to 1 vertical plane projected upwards from the edge of the utility trench.

For footings located on or adjacent to slopes, the footing shall be deepened such that there is a minimum horizontal distance of 5 feet from the edge of the footing to the slope face.

Where footings are to be located adjacent to retaining walls or other structural elements which are not designed for surcharge loading, the new footing shall be deepened below a 45-degree plane projected upwards from the adjacent structure.

All loose and disturbed soil at the bottom of footing excavations shall be removed to firm soil or the disturbed soil shall be compacted prior to laying of steel or pouring of concrete.

Site Class Definition

In accordance with the 2003 International Building Code, Section 1615, the site class and soil profile name may be assumed as B: Rock profile.

Settlement

Under the fully applied recommended bearing pressures, it is estimated that the total settlement of foundations will be less than 1/2 inch.

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Lateral Earth Pressures and Frictional Resistance

The following coefficients for passive earth pressure, active earth pressure (both unrestrained and restrained) and the frictional resistance may be used to design the new structures:

Passive Coefficient (Kp)

Active Coefficient (Ka)

At-rest Coefficient (Ko)

Coefficient of friction

4.60 0.22 0.36 0.60

The unit weight of soil may be assumed as: 130 pcf on-site soil

140 pcf imported structural fill

150 pcf underlying BASALTIC ROCK

Lateral resistance and friction may be combined.

Slab-on-Grade

For design of floor slabs, a modulus of subgrade reaction of 300 pci may be used for the on-site soil, properly compacted structural fill and the underlying BASALT.

Preparation of the subgrade shall be in accordance with the Site Preparation and Grading section to this report.

Slopes

New cut and fill slopes of soil type materials shall not exceed 2 horizontal to 1 vertical. Cuts into the underlying BASALT may be made at 1 horizontal to 4 vertical. Any fractured or loose rock fragment in the exposed rock face shall be removed.

Fill slopes shall be constructed by either overfilling and cutting back to compacted soil.

Exposed slopes shall be covered as soon as practical after construction to minimize erosion.

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Site Preparation and Grading

It is recommended that the site be prepared in the following manner:

1. Clearing and Grubbing:

In all areas to receive fill and in structural areas, all vegetation, weeds, brush, roots, stumps, rubbish, debris, soft soil and other deleterious material shall be removed and disposed of off-site.

2. Preparation of Ground to Receive Fill:

The exposed surface (except rock) shall then be scarified to a depth of 6 inches, moisture conditioned to near optimum moisture (ASTM D1557) and then compacted to the degree of compaction specified below. If soft or loose spots are encountered, the loose/soft areas shall be removed to firm material and the resulting depression shall be filled with properly compacted fill.

3. Types of Fill and Backfill Material:

Structural fill and backfill areas shall be described as areas beneath and extending a horizontal distance of 3 feet beyond the edge of the building line. Non-structural fill areas shall be described as areas beyond 3 feet from the edge of the building line.

4. Material Quality:

Fill and backfill material shall consist of soil which is free of organics and debris. The maximum size particle for fill and backfill material shall be as follows:

a. Structural areas

Top 2 feet below finished subgrade (FSG) 3"

Below 2 feet from FSG 6"

b. Non-structural areas

Top 2 feet from FSG 3"

2 to 6 feet from FSG 6"

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*Below 6 feet from FSG 12"

(FSG = Finished Subgrade Elevation)

*If larger rock or boulders (up to 12 inches in diameter) are used in deep fills, they shall be well embedded. The interstices between the rock or boulders shall be filled with fine-grained material so as to produce a dense compacted mass. If utility lines are to be installed within areas filled with larger material, the maximum particle size shall be reduced to minimize obstruction of trenching work.

Structural fill and backfill material shall have a Unified Soil Classification of either GW, GM, GC, SW, SM, SP or SC. The plasticity index of the fine portion as determined by the ASTM D4318-84 test shall be less than 15.

Retaining wall backfill material and granular fill placed beneath concrete floor slabs may also consist of clean gravel such as #3-fine gravel.

5. Placement of Fill and Backfill:

Each layer of fill and backfill material shall be placed in lifts not exceeding the following (loose thickness):

a. Structural areas

Top 2 feet below finished subgrade (FSG) 8"

Below 2 feet from FSG 12"

b. Non-structural areas

Top 6 feet from FSG 12"

Below 6 feet from FSG *

*The loose thickness of this layer shall not exceed 1.5 times the largest size particle; this is predicated upon proper compaction of each lift.

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Prior to placing, the fill and backfill material shall be aerated or moisture conditioned to near optimum moisture content (ASTM D1557 test procedure).

Where fill is placed on existing ground that is steeper than 5 horizontal to 1 vertical, the existing ground surface shall be benched into firm soil as the fill is placed.

6. Degree of Compaction:

Each layer of fill and backfill material, and the ground surface that is exposed and scarified after clearing and grubbing, shall be thoroughly compacted from edge to edge using conventional compaction equipment. The minimum degree of compaction for each layer (as determined by the

ASTM D1557 test procedure) shall be as follows:

a. Structural areas 95%

b. Non-structural areas *90%

*Where compaction tests are not practical due to the size of the material, each layer shall be compacted by trackrolling until it does not weave or creep under the weight of the trackrolling equipment (D-8 dozer or larger).

It is particularly important to see that all fill and backfill soils are properly compacted in order for the design parameters to remain applicable.

7. Preparation of Footing Excavations:

Prior to placing of steel or pouring of concrete, the bottom of all footing excavations shall be cleaned of loose material and soils that have been disturbed by the excavation process. Any soft or loose soil encountered at the bottom of the footing excavation that cannot be properly compacted shall be removed to firm material. The resulting depression shall then be backfilled with properly compacted structural fill, concrete, controlled low-strength material (CLSM) or other approved backfill material.

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8. Site Drainage:

During construction, drainage shall be provided to minimize ponding of water adjacent to or on foundation and pavement areas. Ponded areas shall be drained immediately. Any subgrade soil that has become soft due to ponding shall be removed to firm material and replaced with compacted structural fill.

It is particularly important to see that all backfill soils are properly compacted especially if these are designed to resist lateral forces.

INSPECTION

During the progress of construction, so as to evaluate compliance with the design concepts, specifications and recommendations contained in this report, qualified engineering personnel should be present to observe the following operations:

1. Site preparation.

2. Placement of fill and backfill.

3. Footing excavations.

REMARKS

The conclusions and recommendations contained herein are based on the findings and observations made at the test boring location. If conditions are encountered during construction which appear to differ from those disclosed by the borings, this office shall be notified so as to consider the need for modifications.

This report has been prepared for the exclusive use of Pacific Wireless Communications, LLC and their respective agents and designers. It shall not be used by or transferred to any other party or to another project without the consent and/or thorough review by this facility. Should the project be delayed beyond the period of one year from the date of this report, the report shall be reviewed relative to possible changed conditions.

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Samples obtained in this investigation will deteriorate with time and will be unsuitable for further laboratory tests within one (1) month from the date of this report. Unless otherwise advised, the samples will be discarded at that time.

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The following are included and complete this report:

Appendix Field Investigation Laboratory Testing Vicinity Map Plot Plan Log of Test Boring Results of Laboratory Tests

APPENDIX

FIELD INVESTIGATION

General

The field investigation consisted of drilling the test boring using a CME 55 drilling rig at the location shown on the Plot Plan. The boring was advanced using 4-inch diameter continuous helical flight augers with the lead auger having a head equipped with changeable cutting teeth. Cuttings were brought to the surface by the continuous flights. After the bore hole was advanced to the required depth and cleaned of cuttings by additional rotation of the augers, the augers were retracted for soil sampling or in-situ testing.

Coring was used to advance the bore hole in the hard rock formation and to obtain a sample of the rock. The core barrel, consisting of a 5-foot long double tube, hardened steel barrel with either a carbide or diamond bit, is attached to drilling rods and set on the hard formation. The boring is advanced through the formation by rotation of the core barrel. Water is used to flush out the cuttings. Upon completion of the core run, the sample is removed from the core barrel and inspected. The total core recovery length and the sum of all intact pieces over 4-inch in length are measured. The length of core recovery divided by the length of the core run is the recovery ratio. The combined length of the 4-inch or longer pieces divided by the length of core run is the Rock Quality Designation (RQD). The values provide an indication of the quality of the formation.

Soil Sampling

Samples of the underlying soils were obtained from borings by driving a soil sampler into the subsurface material using an automatic hammer (equivalent in energy to a 140-pound hammer falling from a height of 30-inches).

Standard Penetration Test (SPT) values and disturbed soil samples were obtained with a 2-inch (outside diameter) split-barrel sampler. The number of blows required to drive the sampler into the ground is recorded at 6-inch intervals. The blow count for the last 12-inches is shown on the boring logs unless changes in the soil material are encountered. If changes are found, the blow counts for other intervals are shown on the logs.

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The soil samples are visually classified in the field using the Unified Soil Classification System. Samples are packed in moisture proof containers and transported to the laboratory for testing.

LABORATORY TESTING

Laboratory testing was limited to the in-place moisture content of the sample due to the characteristics of the formation.

The in-place moisture content of the sample was determined by weighing the sample, then placing the sample into an oven. After oven-drying, the sample is again weighed to determine the moisture loss. The data is used to determine the in-place moisture content.

VICINITY MAP

SELF-SUPPORTING TOWER

HAWAII VOLCANO OBSERVATORY

PROJECT NO.

11-0006

DATE:

02/11

SCALE:

1”=2000’

Shinsato Engineering, Inc.

Consulting Geotechnical Engineers

98-747 Kuahao Pl. Pearl City, HI 96782

PLATE 1

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REFERENCE:

USGS TOPOGRAPHIC MAP

KILAUEA CRATER QUADRANGLE

DATED 1995

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END OF BORING

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13.0

LOG OF BORING NO. 1 ELEVATION (FT.): Unknown

DRILLING METHOD: CME 55 DEPTH OF BORING (FT.): 15

HAMMER WEIGHT (lbs): 140 DEPTH TO GROUNDWATER (FT.): Unknown HAMMER DROP (in): 30 DATE DRILLED: Janaury 25, 2011

Project: SELF-SUPPORTING TOWER

HAWAII VOLCANO OBSERVATORY

Shinsato Engineering, Inc. PLATE Consulting Geotechnical Engineers 3

Project No.: 11-0006 98-747 Kuahao Pl. #E, Pearl City, HI 96782

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