Seed_Project_-_FFD_B284_Geotech_Report.pdf

FINAL LETTER REPORT

GEOTECHNICAL CONSULTATION

PGE Job No. 1875-044 for

SHIMABUKURO, ENDO, & YOSHIZAKI, INC.

FY16 REPAVE PARKING LOT

FEDERAL FIRE DEPARTMENT HEADQUARTERS

BUILDING 284, JOINT BASE

PEARL HARBOR-HICKAM, OAHU, HAWAII

June 7, 2017

Submitted by:

Job No. 1875-044

Shimabukuro, Endo & Yoshizaki, Inc.

1126 12th Avenue, Room 309 Honolulu, Hawaii 96816

Attention: Mr. Howard Endo

Subject: Final Letter Report Geotechnical Consultation FY16 Repave Parking Lot Federal Fire Department Headquarters Building 284, Joint Base Pearl Harbor-Hickam, Oahu, Hawaii

Contract No. N62478-15-D-5022

Gentlemen:

1.0 INTRODUCTION

This letter report presents the results of the geotechnical consultation services we performed for the FY16 Repave Parking Lot, Federal Fire Department Headquarters (FFD HQ), Building 284 project located at Joint Base Pearl Harbor-Hickam (JBPHH), Oahu, Hawaii. Our services were performed in general accordance with our revised September 21, 2016 proposal.

We previously submitted a 100% version of this letter report dated February 24, 2017. We understand there are no review comments regarding our 100% letter report.

The approximate location of the project site is shown on the Map of Area, Plate 1.

A general layout of the site is presented on the Plot Plan, Plate 2.

2.0 PROJECT CONSIDERATIONS

This project includes repair of existing parking lot pavement at Building 284 (B284), removing abandoned islands/beds within the parking lot, redesign of the parking lot to maximize available parking, striping of “No Parking” areas, removal of the existing sidewalk on the east side of the building, installation of a new sidewalk on the north side of the building with tree root barriers, installation of energy efficient lighting for 24-hour operation, grading a larger detention basin near the southwest corner of the building, pavement grading design options to reduce ponding on the east side of the building, and data and communication lines for an intercom and card reader at a gate to the facility.

Pacific Geotechnical Engineers, Inc. 94-417 Akoki Street Waipahu, Hawaii 96797 Telephone: (808) 678-8024 Facsimile: (808) 678-8722 Email: pge@pacificgeotechnical.com

Soils & Foundation Engineering Consultants

Pacific Geotechnical Engineers, Inc.

Shimabukuro, Endo & Yoshizaki, Inc.

FY16 Repave Parking Lot, FFD HQ, B284

The existing asphaltic concrete (AC) pavement in the southern portion of the parking lot, which is used for passenger vehicles, vans, SUVs, and pick-up trucks, will be replaced by new AC pavements. The northern portion of the parking lot, which is used for parking various fire department trucks and vehicles, will be replaced by new plain concrete pavements. A loading dock area on the northwestern portion of the parking lot will be replaced by new AC pavements.

According to the FFD, fire department trucks and vehicles used at the facility in the northern portion of the parking lot include:

Tower 120: Aerial Ladder Truck with a gross vehicle weight rating (GVWR) of 76,800 pounds

AAFF 179: Airfield Rescue and Firefighting Vehicle with a GVWR of 93,000 pounds Crash 176: Airfield Rescue and Firefighting Vehicle with a GVWR of 87,000 pounds

A 4,000 pound lift capacity HYSTER forklift with pneumatic tires is also used at a loading dock area at the northwest corner of Building 284.

3.0 SCOPE OF SERVICES

Based on the above considerations, the following scope of services was performed during design of this project:

1. Review of Readily Available Information – Readily available information on subsurface and geologic conditions in the vicinity of the project site were reviewed.

The sources of this review included record drawings provided by the Commander, Naval Facilities Engineering Command, Hawaii (NAVFAC Hawaii), published geologic reports, and other readily available information.

2. Coordination with Shimabukuro, Endo, & Yoshizaki, Inc. (SEY), NAVFAC Hawaii, FFD HQ, Historic Preservation, and Utility Checking – Prior to the start of the field work, we coordinated our work with Shimabukuro, Endo, & Yoshizaki, Inc.

(SEY) and appropriate personnel from NAVFAC Hawaii and the FFD HQ. During this coordination phase, a proposed boring location plan and a JBPHH Dig Permit Request and historic preservation clearance was prepared and submitted to NAVFAC Hawaii with the assistance of SEY. The Dig Permit was approved by NAVFAC Hawaii before the start of drilling work.

Readily available utility plans were reviewed to check the boring locations for possible underground utility lines. The Hawaii One Call Center (HOCC) and AT&T JHits were contacted to check the boring locations for possible underground utilities. Pural Water Specialty Co., Inc. was subcontracted to perform ground penetration radar (GPR) testing in the vicinity of the boring locations to check for underground structures and utility lines. The boring locations were also toned using a cable locator to check for utilities.

Prior to the start of the field work, we prepared an Activity Hazard Analysis (AHA) of our field activities, which was submitted to SEY for incorporation into its Accident Prevention Plan (APP).

3. Field Exploration – Subsurface conditions in the vicinity of the parking lot and drainage basin were explored by drilling the following soil test borings:

Pavement repair: Eight (8) borings to depths of 10.3 to 11.3 feet below existing grades; and

Drainage Basin: One (1) boring to a depth of 15.3 feet below existing grades.

The borings were drilled using a Mobile B-59 truck mounted drill rig with continuous flight augers. GeoTek Hawaii, Inc. was subcontracted to perform the drilling. The approximate locations of the borings are shown on the Plot Plan, Plate 2. The boring locations and elevations were estimated based on information shown on the project topographic map by ControlPoint Surveying, Inc. (CPS) dated October 25, 2016, and our field measurements using a surveyor’s wheel.

The drilling and sampling were conducted under the technical observation of our engineering personnel, who prepared a log of the subsurface materials encountered in the borings, and obtained relatively undisturbed and disturbed soil samples for examination and laboratory testing.

Relatively undisturbed and disturbed soil samples were obtained from the borings using a stainless steel split barrel sampler with an outside diameter (O.D.) of 3.3 inches and an inside diameter (I.D.) of 2.4 inches and a Standard Penetration Test (SPT) split spoon sampler with an O.D. and I.D. of 2.0 inches and 1.4 inches, respectively. The samplers were driven with blows from a 140-pound hammer falling 30 inches. Each sampling attempt consisted of driving the sampler approximately 18 inches and recording the blow counts for each 6 inches of penetration. The blow counts for the last 12 inches of penetration was recorded and are presented on the logs. The blow counts for the 3.3-inch diameter split barrel sampler have been converted to equivalent SPT blow counts.

After the completion of the drilling, the borings were backfilled with a cement, bentonite, and water mixture to slightly below the AC ground surface. Boring B-5 was filled with the cement mixture to match the existing surface. Borings B-2 through B-4 and B-6 through B-9 were patched with cold-mix AC to match existing pavement conditions. Boring B-1 was backfilled with drill cuttings.

Logs of the borings are presented on Plates 4.1 through 4.9. The soils encountered in the borings were initially classified in the field in general accordance with American Society for Testing and Materials (ASTM) D2488 procedures.

Additional field data from observations of the drilling, soil cuttings, color, drilling rate, and soil sampling were used to supplement our field classifications. The field classifications were later refined in general accordance with ASTM D2487 and the Unified Soil Classification System (USCS) presented on Plates 5.1 and 5.2 based on the results of laboratory tests performed on select soil samples. Volcanic tuff was classified according to the Rock Description System presented on Plate 6.

Four (4) dynamic cone penetrometer (DCP) tests were performed near select boring locations. The DCP test results are presented on Plates 7.1 through 7.4.

One (1) percolation test was performed in the vicinity of Boring B-1 located at the existing drainage basin. The percolation test results are discussed in subsection 5.5 of this letter report.

4. Laboratory Testing – Soil samples obtained from the borings were transported to our laboratory on Oahu for further examination and testing. The laboratory tests performed included moisture content and dry density determination tests, Atterberg Limits, gradation tests, an Expansion Index test, moisture-density relations tests, and single-point California Bearing Ratio (CBR) tests.

The results of the moisture content and dry density determinations are presented on the boring logs on Plates 4.1 through 4.9 at the respective sample depths. Atterberg Limits tests results are presented on Plate 8. Gradation test results are presented on Plate 9. Compaction test results are presented on Plates 10.1 and 10.2. Laboratory California Bearing Ratio (CBR) test results are presented on Plates 11.1 and 11.2.

Expansion Index (EI) test results are presented in Table 1.

5. Engineering Analysis and Letter Report Preparation – Based on the results of the information review, and field exploration and laboratory testing described herein, engineering analysis was performed and comments and recommendations were developed regarding site preparation, anticipated excavation conditions, and guidelines for flexible pavement and plain concrete pavements. The results of this consultation are presented in this letter report.

4.0 REVIEW OF READILY AVAILABLE INFORMATION

Readily available information on general geologic and subsurface conditions in the vicinity of the site was reviewed. A list of reference documents is attached at the end of this letter report. Elevations in this letter report are based on Mean Sea Level datum, unless stated otherwise.

According to as-built drawing 7,030,717, dated 12-7-83, subsurface conditions indicated on the logs of soil test borings for Building 284 generally consisted of about 1 to 3 feet silty coralline and tuff gravel fill, underlain by weathered volcanic tuff to the bottom of these borings at 10 feet. Ground water was not encountered in these borings at the time they were performed in 1980.

According to as-built drawing 7,030,719 titled “Grading and Site Plan” dated 12-7-83, cuts and fills on the order of 1 to 2 feet in thickness were performed for the construction of Building 284 and the existing parking lot on the north and east sides of the building.

According to as-built drawing 7,033,749 titled “Access Road & Grading Plan & Details” dated 12-7-83, the parking lot pavement for Building 284 originally consisted of 2 inches of AC over 6 inches of base course and 12 inches of subbase.

A pavement section consisting of 4 inches of AC over 6 inches of base course and 12 inches of subbase was indicated for the pavement at the intersection of Center Drive with Kamehameha Highway.

The layout of the parking stalls on as-built drawing 7,030,719 differs from the existing parking lot layout. The parking lot was originally designed to have a driveway on the southeast side to be turned into a future roadway. The current driveway is on the northeast side of the stalls. The original parking lot included planting islands at select locations. It is unknown when the parking lot was restriped and reconfigured.

5.0 SITE CONDITIONS

5.1 GENERAL GEOLOGY

The region stretching from the east side of Pearl Harbor to Fort Shafter largely consists of a cluster a tuff cones of the Honolulu Volcanic Series (Stearns, 1939). The two youngest of these tuff cones were built by contemporaneous eruptions from vents in Salt Lake and Makalapa Craters during the Waipio low stand of the sea when sea level may have been 300 feet or more below its present level (Macdonald and others, 1983). The volcanic ejecta derived from the Salt Lake and Makalapa eruptions were deposited sub-aerially and cemented into volcanic tuff rock, also known as mudrock. The Salt Lake eruptions produced the most tuff, which blanketed the older tuff cones (Pankiwskyj, 1972).

The Federal Fire Department parking lot site is located about 1.5 miles east of Salt Lake on the gently sloping southern slope of Makalapa tuff cone. Based on a geologic map of Oahu (Sherrod and others, 2007), the geologic unit at the site has been described as tuff cone deposits. These tuff cone deposits include gray and brown bedded tuff (typically cemented layers of volcanic ash, or pyroclastic fragments finer than 0.5 centimeters in diameter), lapilli tuff (cemented pyroclastic fragments 0.5 to 4 centimeters in diameter), and tuff breccia (cemented pyroclastic fragments greater than 4 centimeters in diameter). At the project site, coarse-grained tuff was erupted from Makalapa, and very fine to fine-grained tuff was most likely erupted from Salt Lake (Pankiwskyj, 1972). At the ground surface, tuff cone deposits generally consist of a thin, clayey residual soil underlain by highly weathered volcanic tuff rock.

The surface soil at the parking lot site has been classified by the United States Department of Agriculture, Natural Resources Conservation Service (NRCS) as Makalapa clay, 2 to 6 percent slopes (MdB). According to the NRCS, MdB soil formed in weathered volcanic tuff and has high shrink and swell tendencies.

5.2 SURFACE CONDITIONS

According to the project topographic map by CPS, dated October 25, 2016, the ground surface in the existing parking lot generally slopes from Center Drive in the east to Building 284 in the west where ground surface elevations range from about +54 feet to +45 feet.

The existing parking lot is paved with AC, except for a roughly 50 feet by 60 feet irregular area near the main entrance to the parking lot that consists of crushed basaltic gravel.

According to the FFD, this area of the parking lot was backfilled with gravel due to severe pavement distress.

Select photos of the existing parking lot are presented on Plates 3.1 through 3.6. The parking lot AC is weathered and raveled. Pavement distress generally consists of areas with moderate to high severity alligator cracking and rutting mainly in the northern portion of the parking lot where fire trucks and heavier vehicles park, and some longitudinal and block cracking in the southern portion.

According to the FFD, ponding and sediment buildup occurs at the western side of the parking lot where containers are stored (see Photo 11 on Plate 3.5) and at the southwestern and southern sides of the lot (see Photo 1 on Plate 3.1). The FFD indicated they installed a shallow drain line at this location to reduce the amount of ponding (see Photo 4 on Plate 3.2).

5.3 ANTICIPATED SUBSURFACE CONDITIONS

Subsurface conditions encountered during our field exploration are presented on the Log of Borings, presented on Plates 4.1 through 4.9. The approximate location of the borings and previous borings by other for Building 284 are shown on the Plot Plan, Plate 2. Because the borings are widely spaced, the actual field occurrence of the geological units and subsurface and groundwater conditions may differ from those indicated on the logs. Depths discussed herein are referenced to existing grades.

Subsurface conditions encountered in Borings B-2 through B-4, and B-6 through B-9, located in AC paved areas, generally consisted of about 2 to 5 inches of AC at the surface, underlain by about 3.5 to 17 inches of silty basaltic gravel. A thin layer of poorly graded basaltic gravel underlain by silty basaltic gravel was encountered at the surface in Boring B-5. In Borings B-3 through B-9, the silty basaltic gravel was underlain by very silty and clayey basaltic and tuffaceous gravel fill to depths of about 1 to 6 feet. In Borings B-3, B-5, and B-9, the silty and clayey gravel was underlain by very soft to medium hard volcanic tuff rock (locally referred to as mudrock) to the bottom of these borings at about 10.3 feet.

The silty and clayey gravel fill in Boring B-2, B-6, and B-7 was underlain by fill material consisting of silty coralline sand, silty and clayey coralline sand, and poorly graded coralline sand, respectively, to depths of about 2.5 to 5 feet. The sand fill in Boring B-6 was underlain by soft to medium hard volcanic tuff rock to the bottom of this boring at about 10.3 feet.

A residual soil layer consisting of stiff to very stiff fat clay was encountered below the sand fill in Borings B-2 and B-7, and below the gravel fill in Borings B-4 and B-8, to depths ranging from 3 to 6 feet. The residual soil was underlain by very soft to medium hard volcanic tuff rock to the bottom of Borings B-2, B-4, and B-8 at about 10.3 feet and the bottom of Boring B-7 at 11.3 feet.

Subsurface conditions encountered in Boring B-1 generally consisted of loose silty coralline sand to a depth of about 1.5 feet, underlain by soft to medium hard volcanic tuff rock to the bottom of this boring at 15.3 feet.

Ground water was not encountered in our borings during our field exploration.

5.4 FIELD DCP AND LAB CBR TESTS

Four (4) Dynamic Cone Penetrometer (DCP) tests were performed near Borings B-3, B-5, B-8, and B-9 in general accordance with ASTM D6951. The DCP results are presented on Plates 7.1 through 7.4.

Moisture-density relations tests and laboratory California Bearing Ratio (CBR) tests were performed on two (2) samples of near surface soils obtained from depths ranging from 0.5 to

5.5 feet. The moisture-density relations test results are presented on Plates 10.1 and 10.2. The laboratory CBR tests results are presented on Plates 11.1 and 11.2.

The field DCP test results are generally consistent with our laboratory CBR test values, except the laboratory values are lower than the DCP tests. This may be due to swelling and softening of the CBR samples, which were compacted on the dry side of optimum moisture content. Field DCP test results generally indicated subgrade CBR values ranging from 4 to 14.

High values of correlated CBR from the DCP tests may be due to obstructions or volcanic tuff rock. The laboratory CBR test results indicate CBR values ranging from 1 to 6 for the subgrade soils that were tested.

The laboratory CBR tests and an EI test indicate the silty and clayey gravel fill encountered in our borings have moderate expansive tendencies, high amounts of fines, and relatively low CBR characteristics.

5.5 FIELD PERCOLATION TEST

One (1) percolation test was performed in a shallow borehole near Boring B-1 to obtain data on the permeability characteristics of the near surface subsurface materials. The test was performed at a depth of 3 feet. The subsurface material tested generally consisted of silty sand fill and volcanic tuff rock. The percolation test indicates slow draining characteristics in the fill and tuff rock. Estimated coefficient of permeability from the test is less than 2 feet per day.

6.0 DISCUSSION

This geotechnical consultation has revealed the following main geotechnical findings:

The existing AC pavement was observed to be in fair to poor condition. Main types of pavement distress observed include raveling, moderate to high severity alligator and block cracking, longitudinal cracking, and some rutting.

Soil test borings performed for this consultation indicate that the parking lot is underlain by variable fill materials generally consisting of very silty and clayey basaltic and tuffaceous gravel and silty and clayey coralline sand. The thickness of the fill varies across the site.

Field and laboratory test results indicate the silty and clayey sand and gravel fill materials and fat clay have moderate expansive tendencies and low CBR characteristics. These materials will tend to swell and soften upon wetting.

Based on a percolation test and our laboratory test results, silty and clayey sand and gravel materials and volcanic tuff rock encountered at the site appear to have slow draining characteristics. It is anticipated the parking lot subgrade has percolation rates of less than 20 feet per day. Per Unified Facilities Criteria (UFC) 3-250-01 Pavement Design for Roads and Parking Areas, dated November 14, 2016, permeable base with subdrains is required for both flexible and rigid pavements planned for this project.

We understand that pavement sections with and without permeable base are being considered. Please note that if permeable base is eliminated from the pavement sections, saturation of the subgrade may occur. This may result in subgrade swelling and softening, and reduction in the pavement life. It may result in early pavement distress and an increase in pavement maintenance.

More detailed discussions and recommendations are presented in the following letter report sections. Recommended minimum pavement sections with and without permeable base are provided in subsection 7.3 of this letter report.

7.0 RECOMMENDATIONS

7.1 SITE PREPARATION AND GRADING

1. Prior to grading, the areas to be graded should be prepared by saw cutting and removing the existing AC pavements. In unpaved areas, the top at least six (6) inches of soils containing vegetation, roots, or organic matter should be stripped and grubbed. Demolished, stripped, and grubbed materials should be hauled to a suitable disposal site off of Government property.

2. As-built conditions of existing utilities to remain, such as their type, size, and inverts, should be field verified to check for any potential conflicts with the pavement repairs. If the crown of a particular existing utility line is close to the bottom of the new pavement sections, the line may get damaged during pavement construction. Care should be taken to reduce potential damage to existing utility lines to remain.

Select existing lines that conflict with the pavement sections, or are located close to or within the new pavement sections, may need to be deepened or jacketed with concrete. It is recommended that we be retained and consulted if existing underground utilities to remain conflict with the new pavements to check if modifications to the recommended pavement sections presented herein are needed.

3. Excavation to depths required for pavement construction are anticipated to generally encounter mainly silty and clayey sand and gravel fill. It is anticipated that these materials can generally be excavated with conventional earthwork equipment.

Excavations or trenches that extend below the fill and into hard volcanic tuff rock will likely require special handling such as the use of a hydraulic hoe ram, or other suitable excavating equipment.

4. Previous as-built drawings show planting islands in select areas of the parking lot.

Fill and subgrade conditions in these islands are unknown. It is recommended that the project include allowances for additional excavation and subgrade treatment that may be needed in these areas.

5. After excavating to the pavement subgrade level, the subgrade should be scarified to a depth of at least six (6) inches, thoroughly moisture conditioned to between optimum moisture content and 3 percent wet of optimum, and compacted to a relative compaction of at least 90 percent, but not more than 95 percent.

Relative compaction in this letter report is defined as the dry unit weight of the compacted material expressed as a percentage of the maximum dry unit weight of the same material based on ASTM D1557 test method.

6. After subgrade compaction, the new pavement subgrade should be proof rolled using a non-vibratory or pneumatic roller with a static weight of at least 20 tons to check for potentially soft, loose, or yielding subgrade areas. Proof rolling should be performed under full-time observation of the Contractor’s Construction Quality Control (CQC) Geotechnical Specialist.

The CQC Geotechnical Specialist should be a United States-licensed civil or geotechnical engineer with at least 10 years of licensed experience, of which 8 years should be in responsible charge in geotechnical engineering in volcanic and alluvial deposits. Responsible charge is defined as being in direct control or personal supervision of geotechnical engineering work.

7. Proof rolling with the roller should be performed no closer than about 5 feet from existing underground utilities to remain. Smaller compaction equipment should be used when compacting within 5 feet of existing underground utilities.

8. Any soft, loose, or yielding subgrade areas detected during the subgrade compaction and proof rolling should be treated by removing the soft or loose materials to firm soils and replacing the excavated material with properly compacted select granular fill or subbase material.

7.2 FILL MATERIALS, PLACEMENT, AND COMPACTION

1. On-site materials encountered in our borings classified as GM, GC, SM, SC, and CH according to the USCS and ASTM D2487 are not suitable for use as select granular material. These materials may be stockpiled for possible re-use in non-structural or landscape areas or as capping fill in non-paved areas. Otherwise, it should be disposed of at a suitable disposal site off of Government property. Other unsuitable soils are materials classified as GC-GM, SC-SM, GP-GC, SP-SC, GW-GC, SW-SC, CL, ML, MH, PT, OL, or OH according to the USCS and ASTM D 2487.

2. On-site granular materials may be used as select granular material provided it meets the material requirements of select granular material recommended in Item 3 of this subsection. Based on available laboratory tests, it is anticipated that most of the on-site silty and clayey sand and gravel would not meet the property requirements recommended herein.

3. Select granular material should consist of granular, generally well-graded material, with particles ranging from coarse to fine and classified as GW, GW-GM, GP-GM, SW, SW-SM, or SP-SM according to the USCS. It should be free of organic matter, vegetation, trash, debris, clayey soil, concrete, old pavements, and particles larger than 3 inches in maximum dimensions. It should have less than 15 percent of fines by weight passing a No. 200 standard sieve. It should have a CBR value of at least 30, a CBR swell of less than one percent when compacted at optimum moisture content and after 4 days of soaking, a liquid limit of 25 percent or less, and a plasticity index of 10 or less.

4. Select granular material should be placed in not more than 8-inch thick horizontal, loose lifts, moisture conditioned to within 2 percent of the optimum moisture content for this material, and compacted to a relative compaction of at least 95 percent.

5. All on-site and imported materials should be checked, and if appropriate, tested and approved by the Contractor’s CQC Geotechnical Specialist prior to their use in fills at the site. An adequate number of field density tests should be performed by the Contractor’s quality control testing firm to check that the required degree of compaction has been achieved.

7.3 PAVEMENTS

7.3.1 General

The pavement sections presented herein were developed based on the United States Army Corps of Engineers (USACE) pavement design program, Pavement- Transportation Computer Assisted Structural Engineering (PCASE), version 2.09.05 and a 25-year design life as required by UFC 3-250-01 Pavement Design for Roads and Parking Areas.

According to the FFD, traffic at the Building 284 parking lot will consist mainly of passenger vehicles, pickup trucks, SUVs, and vans on the AC paved parking area, heavier vehicles, such as fire department trucks on the concrete pavement area, and a HYSTER 4,000-pound capacity forklift on both the AC and concrete sections, as described in section 2.0 of this letter report.

The following traffic frequency was assumed in our analysis based on input from the FFD:

One trip per day for a Tower 120 truck One trip per week for the ARFF 179 and Crash 176 vehicles.

Traffic frequency for passenger vehicles, pickup trucks, SUVs, and vans was based upon the number of parking stalls to be provided for the new parking lot.

Turn-over per parking stall was assumed to be two times per day.

The flexible and rigid pavement recommendations presented herein are based on the above considerations. A plain concrete flexural strength of 650 pounds per square inch (psi) was assumed for rigid pavement. For pavement sections with untreated permeable base (UPB) and subdrains, a subgrade CBR of 4 for flexible pavements, and a subgrade modulus of 120 pounds per square inch per inch (psi/in) for rigid pavement were assumed. Saturation and softening of the subgrade may occur without permeable base and subdrains. For pavement sections without UPB and subdrains, a subgrade CBR of 2 for flexible pavements, and a subgrade modulus of 75 psi/in for rigid pavement were assumed.

7.3.2 Flexible and Rigid Pavements

1. The following minimum flexible pavement sections with UPB and without UPB for the parking lot and loading dock areas are recommended:

Flexible Pavement with UPB

4 inches of AC 6 inches of untreated aggregate base course (AB) 8 inches of UPB Non-woven geotextile fabric 6 inches of aggregate subbase (AS) compacted subgrade

Flexible Pavement without UPB

4 inches of AC 6 inches of AB 20 inches of AS Woven geotextile fabric

2. The following minimum rigid pavement sections with UPB and without UPB are recommended:

Rigid Pavement with UPB

8.5 inches of plain concrete 8 inches of UPB Non-woven geotextile fabric 6 inches of AS

Rigid Pavement without UPB

8.5 inches of plain concrete 20 inches of AB Woven geotextile fabric

3. Subdrains should be provided for new flexible and rigid pavements with UPB as recommended in subsection 7.3.4 of this letter report.

4. Non-woven geotextile fabric, such as Mirafi 180N or equal is recommended for pavement sections with UPB. Woven geotextile fabric, such as Mirafi HP570 or equal is recommended for sections without UPB.

5. Aggregate subbase should conform to the material property requirements for select granular fill in subsection 7.2 of this letter report.

Aggregate subbase should be placed in not more than 8-inch thick loose lifts, moisture conditioned to within 2 percent of optimum moisture content, and compacted to a relative compaction of at least 95 percent. The subgrade should be properly compacted as recommended in subsection 7.1 of this letter report prior to the placement of subbase materials.

6. Aggregate base course should conform to the material requirements of Section

703.06 of the Hawaii Standard Specifications for Road, Bridge and Public Works Construction dated 2005, hereafter referred to as the Hawaii Standard Specifications. It should have a nominal size of 1.5 inches.

Aggregate base course should be placed in not more than 8-inch thick loose lifts, moisture conditioned to within 2 percent of optimum moisture content, and compacted to a relative compaction of at least 100 percent.

7. The base course and subbase should extend at least one foot beyond the AC limits.

8. In general, plain concrete pavements should be jointed and unreinforced, except at joints, and as recommended herein. Joints should be reinforced with dowels or deformed bars depending on joint type.

9. Pavement slab sections with odd shapes and slab sections with a length to width ratio larger than 1.25 should be reinforced in two directions normal to each other using a minimum of 0.05 percent steel in both directions per UFC 3-250-01.

10. Joints in the plain concrete pavement should be sealed with a sealing compound to reduce potential infiltration of surface water into the pavement.

7.3.3 Untreated Permeable Base (UPB)

1. UPB for plain concrete pavements should consist of clean, granular basaltic gravel conforming to the property requirements per Hawaii Standard Specifications Section 703.04.

2. UPB should be placed in not more than 8-inch thick loose lifts. Each lift should be compacted to a dense consistency with non-vibratory compaction equipment.

The UPB should be compacted until little to no settlement of the gravel is observed under repeated passes, but not less than six (6) passes.

After rolling, a thin layer of basaltic filler material not exceeding about should be spread over the coarse aggregate surface to act as a choke layer to facilitate subsequent paving. Placement of filler material should conform to Hawaii Standard Specifications Section 306. Filler material should conform to Hawaii Standard Specifications Section 703.04.

3. After compaction of the UPB has been performed and prior to paving, construction equipment, trucks, and vehicles should not be allowed to drive on the compacted UPB. Areas that are disturbed, rutted, or contaminated from sediments, dust, dirt, or foreign material should be removed and replaced with clean UPB.

7.3.4 Pavement Subdrains

1. A subdrain system should be installed to collect surface water that accumulates in the UPB below the AC and concrete pavement sections. According to UFC 3-250-01, a subsurface drainage system is required for flexible and rigid pavements where the subgrade permeability is less than 20 feet per day. Based on subsurface conditions encountered in our borings and the percolation and laboratory test results, the existing pavement subgrade appears to have permeabilities much less than 20 feet per day.

2. Collection subdrains along the downslope or mainly western side of the parking lot pavements are recommended for pavement sections with UPB. Select transverse subdrains may also be required depending on how the parking lot is graded.

3. UPB subdrains should consist of perforated or slotted drainage pipes bedded in

ASTM D448, No. 67 size basaltic drainage gravel and a non-woven geotextile fabric as described herein. The pipe should be at least 6 inches in diameter and installed with its perforations or slots facing down. The pipes should be sloped to discharge to suitable drainage facilities.

The drainage pipes should be installed in trenches excavated to a depth of at least 12 inches below the bottom of the UPB. The trenches should be at least 18 inches wide and lined with a non-woven geotextile fabric such as Mirafi 160N or equal.

The fabric should overlap at least 12 inches along all joints.

The pipes should be bedded in ASTM D448 No. 67 size basaltic gravel such that at least 3 inches of gravel is provided below the pipes. The basaltic gravel should be placed in horizontal lifts not exceeding 6 inches in loose thickness and compacted to a dense consistency as indicated by little to no settlement of the gravel under repeated passes, but not less than six (6) passes per lift.

7.3.5 Other Pavement Considerations

The parking lot pavement repairs will include conditions where flexible pavements will abut rigid pavement. It is recommended that a buried concrete slab be installed under the adjoining AC material as suggested in Figure 12-36 of UFC 3-260-02 Pavement Design for Airfields, dated June 30, 2001. Suggested installation procedures are also noted in this figure.

7.4 DRAINAGE BASIN

Volcanic tuff rock was encountered at a depth of about 1.5 feet in Boring B-1. As discussed in subsection 5.5 of this letter report, the tuff rock has slow draining characteristics.

Depending on the depth of the new basin it is anticipated that its bottom may be mainly in tuff rock. A coefficient of permeability of 2 feet per day may be assumed for the tuff rock.

7.5 SIDEWALK

Silty and clayey sand and gravel encountered in our borings appear to be moderately expansive. It is recommended that at least 24 inches of properly compacted select granular fill be placed under sidewalks. The fill should be placed and compacted as recommended in subsection 7.2 of this letter report.

8.0 REVIEW OF PRE-FINAL PLANS AND SPECS, AND SERVICES DURING

CONSTRUCTION

During the design, we plan to review the geotechnical-related section of the pre-final plans and specifications to check that the intent of the recommendations presented herein are properly reflected in the contract documents.

During construction, we should be retained to observe certain critical phases of the parking lot construction such as subgrade preparation and compaction. Our involvement during subgrade preparation and pavement construction will allow us to develop modifications to our recommendations, if necessary, should subsurface conditions differ from those presented in this letter report.

9.0 LIMITATIONS

This letter report has been prepared specifically for the use of Shimabukuro, Endo & Yoshizaki, Inc. and Naval Facilities, Hawaii, in accordance with generally accepted soils and foundation engineering practices, for planning of the FY16 Repave Parking Lot, FFD HQ, B284 project at Joint Base Pearl Harbor-Hickam, Hawaii, subject to the limitations of our scope, schedule, and budget for this project. It does not contain sufficient information for the purposes of other parties or for other uses. No warranty or guarantee, expressed or implied, or other representation is made as to the professional advice included in this letter report and none should be inferred.

No third party including bidders and contractors may rely upon this letter report and any document prepared by us unless we agreed to such reliance in advance and in writing. Pacific Geotechnical Engineers, Inc. (PGE) is not responsible for any claims, damages, or liability associated with the use of the information presented in this letter report by any other party.

This letter report does not reflect variations which may occur in the subsurface and groundwater conditions at the site between borings. The nature and extent of variations in the subsurface and groundwater conditions may not become evident until construction.

This letter report does not reflect any changes in the pavement conditions that may occur subsequent to our field exploration. Pavement conditions may continue to deteriorate between the time of this consultation and the actual construction.

Ground water was not encountered in our borings at the time of our field exploration.

However, fluctuations in the groundwater level may occur due to variations in rainfall, tides, seepage, irrigation, temperature, surface runoff infiltration, and other factors that may be different from the conditions that existed at the time of our measurements.

The comments and recommendations presented in this letter report are based on the anticipated construction described herein. Should the actual construction differ from that described in this letter report, we should be notified and retained to check if any modifications to the recommendations presented in this letter report are needed. Any modification of comments and recommendations to this letter report shall not be considered valid unless the changes are revised by us and the recommendations in this letter report revised or modified in writing.

The subsurface exploration portion of this consultation may not have disclosed the presence of underground structures, such as cesspools, drywells, storage tanks, sumps, pits, buried debris, and landfills, etc., that may be present at the site. Should these items be encountered during construction, we should be retained and consulted to develop appropriate recommendations for their disposal and/or treatment. Assessment of the presence or absence of these items was not included in the scope of this consultation.

The scope of our services did not include any environmental assessment or evaluation of potential subsurface and groundwater contamination. Silence in this letter report regarding any environmental aspects of the site subsurface and groundwater conditions do not indicate the absence of potential environmental problems.

The scope of our services specifically excluded the investigation, detection, or assessment of the presence of Biological Pollutants in or around any existing or planned structure. Accordingly, this report includes no interpretations, recommendations, findings, or conclusions for the purpose of detecting, preventing, assessing, or abating Biological Pollutants.

The term “Biological Pollutants” includes, but is not limited to molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts.

- o0o -

General Location of Project Site

FEET

KILOMETER

Contour Interval 40 Feet

Datum is Mean Sea Level

Depth Curves in Feet - Datum is Mean Lower Low Water

0 2000

0.5

N m a p o f a r e a d w g

Reference:

U.S.G.S. Topographic Map

Pearl Harbor, Oahu, Hawaii

Dated: 1999

MAP OF AREA

FY16 Repave Parking Lot Building 284

Federal Fire Department Headquarters

Joint Base Pear Harbor Hickam, Hawaii

PLATE

J e n g i n e e r i n g c a d m a p o f a r e a d w g

M a p o f

A r e a

A

M

B-9

B-8

B-7

B-6

B-5

B-4

B-3

B-2

B-1

PLOT PLAN

FY16 Repave Parking Lot Building 284

Federal Fire Department Headquarters

Joint Base Pearl Harbor-Hickam, Hawaii

PLATE

l o t p l a n

C

P L d g

Reference:

Topographic Survey Map

By: Controlpoint Surveying, Inc.

Dated: October 25, 2016

Site Layout Plan (Sheet C-102)

From: Shimabukuro Endo Yoshizaki, Inc.

Received: January 6, 2017

Grading and Site Plan (Sheet C-3)

New CPO Mess, Bldg. 284

NAVFAC Drawing No. 7,030,719

Dated December 7, 1983

Legend:

B-1

Approximate PGE Boring

Location and Number

Approximate Location and Number of Previous Boring by Other

Approximate Location and Direction of PGE Photo and Number

Scale Feet

40 80200

J e n g i n e e r i n g c a d p l o t p l a n

C

P

L d w g

C

P

L

SITE PHOTOGRAPHS

FY16 Repave Parking Lot at Federal Fire Department Headquarters, Building 284

JBPHH, Hawaii

Pacific Geotechnical Engineers, Inc.

PLATE

3.1

-0 s ite p ho to s.

pp t

/2

3/

0:

A M

Photo 1 – Looking north at existing parking lot.

Photo 2 – Looking north at existing parking lot.

Area of ponding

Department Headquarters, Building 284

JBPHH, Hawaii

Pacific Geotechnical Engineers, Inc.

PLATE

3.2

-0 s ite p ho to s.

pp t

/2

3/

0:

A M

Photo 3 – South end of parking lot and gate to Center Drive (looking east).

Photo 4 – Existing sump area. Note discharge end of existing drainline (looking northeast).

Drainline installed by FFD

Department Headquarters, Building 284

JBPHH, Hawaii

Pacific Geotechnical Engineers, Inc.

PLATE

3.3

-0 s ite p ho to s.

pp t

/2

3/

0:

A M

Photo 5 – Looking north of existing AC pavement in the vicinity of Boring B-3.

Photo 6 – Looking north at existing AC pavement on east side of parking lot.

Boring B-3

Department Headquarters, Building 284

JBPHH, Hawaii

Pacific Geotechnical Engineers, Inc.

PLATE

3.4

-0 s ite p ho to s.

pp t

/2

3/

0:

A M

Photo 7 – Looking west at AC parking lot area where FFD trucks and vehicles park.

Photo 8 – Looking northwest at northern portion of parking lot.

Department Headquarters, Building 284

JBPHH, Hawaii

Pacific Geotechnical Engineers, Inc.

PLATE

3.5

-0 s ite p ho to s.

pp t

/2

3/

0:

A M

Photo 9 – Looking northeast at existing entry area to parking lot.

Photo 10 – Looking east at northern portion of parking lot. Ponding/sediment accumulation occurs in grass area of pavement according to FFD.

Existing Entry/Exit

Department Headquarters, Building 284

JBPHH, Hawaii

Pacific Geotechnical Engineers, Inc.

PLATE

3.6

-0 s ite p ho to s.

pp t

/2

3/

0:

A M

Photo 11 – Looking west of container area where ponding occurs according to FFD.

Photo 12 – Looking east at main entry/exit area to Center Drive. Note gravel area in right side of photo where pavement was severely distressed according to FFD.

Ponding/ sediment build-up

Gravel Area

Light brownish gray and white silty coralline sand, loose, with coralline gravel, moist (fill)

Very dark brown volcanic tuff rock, soft to medium hard, highly to moderately weathered grades dark yellowish brown grades very dark grayish brown, medium hard, and moderately weathered grades dark gray grades very dark grayish brown grades very soft to soft, and completely to highly weathered grades very dark gray, medium hard, and moderately weathered grades very dark brownish gray, soft to medium hard, and highly to moderately weathered

Boring completed at 15.3 feet on 11/18/2016.

Ground water not encountered.

17 94

SM

100/7"

100/7"

50/5"

50/4"

45/3"

47/3"

90/6"

40/3"

82/7"

86/9"

40/3"

40/3"

40/3"

SURFACE

Drilling Equipment Mobile B-59Drilling Method 4-inch Augers

Logged By J. Galacgac

Date Ended 11/18/2016 Datum Mean Sea Level

Date Started 11/18/2016 ± feet

Water Level (depth) Not Encountered

Surface Elevation +48.3

Description Lab Data

M oi st ur e C on te nt

R ec ov er y

D ry

D en si ty

(p cf

C or e T yp e

Core Info

S am pl es

G ra ph ic

L og

S oi l C la ss

R Q

D

D ep th ft)

B lo w s/ ft

P la st ic ity In de x

Li qu id Li m it

Drawn By LML

Job No. 1875-044Project Repave Parking Lot, Building 284

Location Joint Base Pearl Harbor-Hickam, Hawaii BORING B-1 (Page 1 of 1)

B O

R E

H O

LE

L

O G

T R

U E

S C

A

LI

N G

P

A C

IF

IC

G E

O T

E C

H N

IC

A

L F

IN

A

L D

A T

A T

E M

P

LA

T E

.G D

T

/2

/1

2:

J

-0

\E

N G

IN

E

E R

IN

G

\G T

G S

O R

G

IN

T \1

-0

B -L

O G

S _L

A B

.G P

J

PLATE

4.1 Disturbed sample

Notes: LOG OF BORING

Sample lost during extraction

Core run

2-inch O.D. SPT (split-spoon sample)

DRIVING ENERGY: 140 lb dropping 30 inches

3.3-inch O.D. split barrel sample

2.5

5.0

7.5

10.0

12.5

15.0

4 inches of asphaltic concrete Grayish brown silty basaltic gravel, with basaltic sand, moist (fill)

Light brownish gray and white silty coralline sand, loose, with coralline and basaltic gravel, moist (fill)

Dark yellowish brown fat clay, very stiff, with highly weathered tuffaceous sand, moist (completely weathered volcanic tuff rock) Grayish brown volcanic tuff rock, soft to medium hard, highly to moderately weathered grades dark grayish brown grades very dark gray

Boring completed at 10.3 feet on 11/18/2016.

Ground water not encountered.

20 85

AC

GM

SM

CH

52/8"

40/4"

50/5"

40/3"

40/3"

40/3"

40/2"

40/3"

SURFACE

Drilling Equipment Mobile B-59Drilling Method 4-inch Augers

Logged By J. Galacgac

Date Ended 11/18/2016 Datum Mean Sea Level

Date Started 11/18/2016 ± feet

Water Level (depth) Not Encountered

Surface Elevation +51.3

Description Lab Data

M oi st ur e C on te nt

R ec ov er y

D ry

D en si ty

(p cf

C or e T yp e

Core Info

S am pl es

G ra ph ic

L og

S oi l C la ss

R Q

D

D ep th ft)

B lo w s/ ft

P la st ic ity In de x

Li qu id Li m it

Drawn By LML

Job No. 1875-044Project Repave Parking Lot, Building 284

Location Joint Base Pearl Harbor-Hickam, Hawaii BORING B-2 (Page 1 of 1)

B O

R E

H O

LE

L

O G

T R

U E

S C

A

LI

N G

P

A C

IF

IC

G E

O T

E C

H N

IC

A

L F

IN

A

L D

A T

A T

E M

P

LA

T E

.G D

T

/2

/1

2:

J

-0

\E

N G

IN

E

E R

IN

G

\G T

G S

O R

G

IN

T \1

-0

B -L

O G

S _L

A B

.G P

J

PLATE

4.2 Disturbed sample

Notes: LOG OF BORING

Sample lost during extraction

Core run

2-inch O.D. SPT (split-spoon sample)

DRIVING ENERGY: 140 lb dropping 30 inches

3.3-inch O.D. split barrel sample

2.5

5.0

7.5

10.0

4 inches asphaltic concrete

Very dark brown clayey basaltic gravel, loose, with some coralline sand, moist (fill)

Very dark grayish brown silty tuffaceous gravel, medium dense, with trace of coralline sand, moist (fill)

Very dark grayish brown volcanic tuff rock, very soft to soft, completely to highly weathered grades medium hard and moderately weathered grades soft to medium hard and highly to moderately weathered grades medium hard and moderately weathered

Boring completed at 10.3 feet on 11/18/2016.

Ground water not encountered.

26 95

AC

GM

GC

GM

75/7"

40/3"

45/4"

40/3"

40/3"

40/3"

45/4"

SURFACE

Drilling Equipment Mobile B-59Drilling Method 4-inch Augers

Logged By J. Galacgac

Date Ended 11/18/2016 Datum Mean Sea Level

Date Started 11/18/2016 ± feet

Water Level (depth) Not Encountered

Surface Elevation +49.4

Description Lab Data

M oi st ur e C on te nt

R ec ov er y

D ry

D en si ty

(p cf

C or e T yp e

Core Info

S am pl es

G ra ph ic

L og

S oi l C la ss

R Q

D

D ep th ft)

B lo w s/ ft

P la st ic ity In de x

Li qu id Li m it

Drawn By LML

Job No. 1875-044Project Repave Parking Lot, Building 284

Location Joint Base Pearl Harbor-Hickam, Hawaii BORING B-3 (Page 1 of 1)

B O

R E

H O

LE

L

O G

T R

U E

S C

A

LI

N G

P

A C

IF

IC

G E

O T

E C

H N

IC

A

L F

IN

A

L D

A T

A T

E M

P

LA

T E

.G D

T

/2

/1

2:

J

-0

\E

N G

IN

E

E R

IN

G

\G T

G S

O R

G

IN

T \1

-0

B -L

O G

S _L

A B

.G P

J

PLATE

4.3 Disturbed sample

Notes: LOG OF BORING

Sample lost during extraction

Core run

2-inch O.D. SPT (split-spoon sample)

DRIVING ENERGY: 140 lb dropping 30 inches

3.3-inch O.D. split barrel sample

2.5

5.0

2 inches of asphaltic concrete

Very dark brown clayey tuffaceous gravel, medium dense, with some tuffaceous sand, moist (fill) grades dark reddish brown and dark gray, and with basaltic gravel grades loose

Dark grayish brown fat clay, very stiff, with tuffaceous gravel, moist (residual soil)

Very dark grayish brown volcanic tuff rock, very soft, completely weathered grades soft to medium hard and highly to moderately weathered grades dark gray, medium hard, and moderately weathered grades very dark grayish brown, soft to medium hard, and highly to moderately weathered

Boring completed at 10.3 feet on 11/18/2016.

Ground water not encountered.

AC

GM

GC

CH

20/6"

30/4"

50/5"

50/5"

50/3"

50/4"

50/3"

SURFACE

Drilling Equipment Mobile B-59Drilling Method 4-inch Augers

Logged By J. Galacgac

Date Ended 11/18/2016 Datum Mean Sea Level

Date Started 11/18/2016 ± feet

Water Level (depth) Not Encountered

Surface Elevation +51.2

Description Lab Data

M oi st ur e C on te nt

R ec ov er y

D ry

D en si ty

(p cf

C or e T yp e

Core Info

S am pl es

G ra ph ic

L og

S oi l C la ss

R Q

D

D ep th ft)

B lo w s/ ft

P la st ic ity In de x

Li qu id Li m it

Drawn By LML

Job No. 1875-044Project Repave Parking Lot, Building 284

Location Joint Base Pearl Harbor-Hickam, Hawaii BORING B-4 (Page 1 of 1)

B O

R E

H O

LE

L

O G

T R

U E

S C

A

LI

N G

P

A C

IF

IC

G E

O T

E C

H N

IC

A

L F

IN

A

L D

A T

A T

E M

P

LA

T E

.G D

T

/2

/1

2:

J

-0

\E

N G

IN

E

E R

IN

G

\G T

G S

O R

G

IN

T \1

-0

B -L

O G

S _L

A B

.G P

J

PLATE

4.4 Disturbed sample

Notes: LOG OF BORING

Sample lost during extraction

Core run

2-inch O.D. SPT (split-spoon sample)

DRIVING ENERGY: 140 lb dropping 30 inches

3.3-inch O.D. split barrel sample

2.5

5.0

Gray poorly graded basaltic gravel, moist (fill) Grayish brown silty basaltic gravel, moist (fill) Very dark grayish brown clayey tuffaceous gravel, medium dense, with sand, moist (fill)

Dark grayish brown volcanic tuff rock, medium hard, moderately weathered grades soft and highly weathered grades soft to medium hard and highly to moderately weathered

Boring completed at 10.3 feet on 11/17/2016.

Ground water not encountered.

28 91

GP

GM

GC

26/10"

17/2"

18/2"

15/3"

20/3"

15/2"

20/2"

20/4"

10/3"

15/4"

SURFACE

Drilling Equipment Mobile B-59Drilling Method 4-inch Augers

Logged By J. Galacgac

Date Ended 11/17/2016 Datum Mean Sea Level

Date…