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GEOTECHNICAL REPORT

VA INPATIENT MENTAL HEALTH BUILDING

FAYETTEVILLE, ARKANSAS

for

MICHAEL ROTH AND ASSOCIATES

ST. LOUIS, MISSOURI

EXECUTIVE SUMMARY

This is a report of the findings of subsurface exploration for the proposed Veterans

Affairs (VA) Inpatient Mental Health Building project south of the existing Mental Health

Building on the VA campus in Fayetteville, Arkansas. This report includes recommendations for site grading, structure foundations, lateral earth pressures, and pavement sections for the new inpatient facility project. The following is a summary of significant findings:

• A total of nine (9) borings were conducted across the planned project improvements area. The boring locations can be referenced in Appendix A on Plate 1

• Six (6) borings (B-1, B-2, B-3, B-4, B-5, and B-6) were conducted within the proposed new building footprint. The borings within the proposed building footprint encountered auger refusal material between 17 and 45 feet below existing ground/pavement elevations. Borings B-2, B-3, and B-6 were then extended into the basal rock formations for further sampling and analysis.

• One (1) boring (B-7) was conducted in the proposed courtyard area, where it is our understanding that a retaining wall is planned.

• Two (2) borings (Borings B-8 and B-9) were conducted in planned paved parking lot and driveway areas. Boring B-8 was conducted in an area of planned new pavement and B-9 was conducted in an existing pavement area to evaluate the in-place pavement conditions.

• The majority of the project site consists of existing asphalt-paved parking lots and driveway areas. Borings B-2, B-3, B-4, B-5, B-7, and B-9 were conducted in areas with existing asphalt pavement. These borings encountered existing asphalt thicknesses that varied from 2.5 to 4.0 inches. The existing pavement was underlain by granular base course material that varied in thickness from six (6) to nine (9) inches.

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• Subgrade soils at the project site were generally sandy and were weathered representations of the onsite sandstone material that exists above the basal shale formation at greater depths.

• Onsite soils should not be used as select fill material on the project, but may be used as general fill material outside of planned building and pavement areas. Select fill material for the project should conform to the recommendations in this document and should be approved by the Geotechnical Engineer.

• In the non-paved locations of Borings B-1, B-6, and B-8, a surface stratum of dark brown silty topsoil with vegetation/organics was encountered to a depth of six (6) inches at the boring locations. A topsoil thickness of up to twelve (12) inches is common in the project area and should be anticipated for project grading in non-paved areas.

• The groundwater table was not encountered by the boring terminal depths at the time of the onsite investigation. Groundwater in the form of perched water tables and saturated soils were encountered immediately above the basal rock formation in isolated boring locations. Perched water tables are common in the project area, particularly above the basal shale formation.

• A planned finish-floor elevation (FFE) of 1467.3 is anticipated for the planned new inpatient facility structure.

• The project structure should be placed on a foundation system bearing on one (1) of the following two (2) options:

o OPTION 1). The building additions may be placed on a shallow foundation system composed of continuous and individual (spread) foundations. The shallow foundations should bear in the stable Stratum II soils. Footings placed as recommended may be designed for safe allowable bearing capacities of 2,000 pounds per square foot (psf) for continuous foundations and 2,500 psf for spread or individual foundations. The provided bearing capacities were derived using a factor of safety of three (3).

o OPTION 2). Alternatively, the building additions may be placed on a hollow-stem micropile foundation system. The micropiles should bear in the medium-hard Stratum IV gray shale material. The pile system should be designed using the values presented in Table 3 in the report.

• Minimum pavement sections in new pavement areas are recommended to be as shown in the following table:

Standard Duty Heavy Duty

C o n cr e te

P a v e m e n t Portland Cement Concrete 4" 6"

Class 7 Base Course (95% MPD) 6" 10"

Stable Subgrade or Compacted Select Fill (98% SPD) As Required As Required

A sp h lt v e m e n t ACHM Surface Course (1/2") 3" 3"

ACHM Binder Course (1") N/A 3"

Class 7 Base Course (95% MPD) 8" 12"

Stable Subgrade or Compacted Select Fill (98% SPD) As Required As Required

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TABLE OF CONTENTS

TITLE PAGE NO.

Executive Summary i - ii

Introduction 1

Project Description 1 - 2

Field Investigation 2 - 4

Laboratory Tests 4 - 5

Site Geology 5

General Soil Conditions 6 - 8

IBC Site Classification 7

Fine-Grained Soil Analysis 7 - 8

Analysis and Recommendations 9 - 22

Site Preparation and Grading 9

General Structure Foundation Recommendations 10

Building Foundation Recommendations - Shallow 11 - 13

Building Foundation Recommendations - Micropile 14 - 15

Statement Regarding Drilled Pier Foundations 15

Groundwater - Site Dewatering 16

Building Slab-on-Grade 16 - 17

Site Retaining Structures - Lateral Earth Pressures 18 - 19

Select Fill Material 19 - 20

Rock Excavation 20

New Pavement Areas 21

Minimum Project Pavement Recommendations 21 - 22

Limitations and Reserved Rights 23

FIGURES AND TABLES

Table 1: Boring and Refusal Material Elevations Page 3

Table 2: Depths to Stable Subgrade Material Page 12

Table 3: Onsite Soil Structural Properties Page 14

Table 4: Lateral Earth Pressure Design Values Page 18

Table 5: Minimum Project Pavement Sections Page 22

APPENDICIES

A: Boring Layout Plate 1

B: Boring Logs Plates 2 - 11

C: Laboratory Testing Results Plates 12 - 14

D: Generalized Soil Profiles Plates 15 - 16

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GEOTECHNICAL REPORT

VA INPATIENT MENTAL HEALTH BUILDING

FAYETTEVILLE, ARKANSAS

for

MICHAEL ROTH AND ASSOCIATES

ST. LOUIS, MISSOURI

INTRODUCTION

An investigation of subsurface soil conditions was conducted by McClelland Consulting

Engineers, Inc., for the proposed VA Inpatient Mental Health Building project in

Fayetteville, Arkansas. The investigation was requested and authorized by Ms. Elaine

Lewis with Michael Roth and Associates in St. Louis, Missouri to investigate subsurface soil conditions at the project site and to prepare recommendations for items including site grading, structure foundations, lateral earth pressures, and pavement sections for the new building project.

PROJECT DESCRIPTION

The proposed project site is located south of the existing Mental Health Building on the

VA campus in Fayetteville, Arkansas. The majority of the project site consists of existing asphalt-paved parking lots and driveway areas. The current project scope is understood to include new construction of a 28,465 square feet single-story facility. The facility is to be designed with the intent of adding a future second floor. A retaining wall is currently anticipated in the courtyard area. Basement elevations and/or underground detention structures are not currently planned within the project scope.

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The building construction is anticipated to be slab-on-grade with light-gauge metal stud walls and brick masonry veneer. A planned finish-floor elevation (FFE) of 1467.3 is anticipated for the recommendations in this report. Maximum loading for the building structure is anticipated to be in the order of 2.0 kips per linear foot for exterior walls and

30 kips for interior foundations beneath column supports.

FIELD INVESTIGATION

The subsurface soil conditions at the planned project site were investigated by nine (9) borings. The building borings (B-1 through B-6) were conducted within the planned building footprint and encountered auger refusal material between 17 and 45 feet below existing ground/pavement elevations. Borings B-2, B-3, and B-6 were then extended into the basal rock formations for further sampling and analysis. Boring B-7 was conducted in the area of the proposed courtyard where a retaining wall is understood to be planned. Boring B-8 was conducted in an area of planned new pavement and B-9 was conducted in an existing pavement area to evaluate the in-place pavement conditions. Borings B-7, B-8, and B-9 reached their planned terminal depths of 10.5 feet, 5.5 feet, and 6.5 feet, respectively.

The project borings were conducted using a truck-mounted rotary drilling rig with a six and one-half (6-½) inch hollow-stem auger. Soil samples were obtained at the depths indicated on the boring logs by the use of a two (2) inch split-spoon sampler for obtaining samples from non-cohesive or slightly cohesive soils. The split-spoon sampler was driven by blows from a 140-pound hammer dropped 30 inches. The number of blows required to drive the split-spoon sampler the final twelve (12) inches of an

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Health Building Geotechnical Report.doc 3 eighteen (18) inch drive, or portion thereof, is referred to as the Standard Penetration value, N, and is recorded on the boring logs in the blows-per-foot column. Auger refusal material was encountered at each of the building boring locations. When auger refusal material was encountered in Borings B-2, B-3, and B-6, they were then advanced into the basal shale formation using a three (3) inch diamond-tipped, double-tube core bit and core sampler. Recovery percentages from core sampling were generally low due to the sandy and friable nature of the weathered sandstone and shale formations.

The boring locations can be referenced in Appendix A on Plate 1. Table 1 below shows the depths and elevations of the project borings and the depth at which refusal material was encountered.

TABLE 1: Boring Elevations and Encountered Refusal Material

Boring Ground

Elevation Bottom

Elevation Depth Drilled

(ft) Auger Refusal

Depth (ft)

B-1 1466.0 1439.5 26.5 26.5

B-2 1466.7 1423.7 43.0 36.5

B-3 1466.3 1419.8 46.5 26.5

B-4 1468.9 1442.4 26.5 26.5

B-5 1469.5 1452.5 17.0 17.0

B-6 1473.4 1423.4 50.0 45.0

B-7 1462.3 1451.8 10.5 N/A

B-8 1464.2 1458.7 5.5 N/A

B-9 1466.1 1459.6 6.5 N/A Note: Ground elevations shown in Table 1 are rounded to the nearest 0.1 foot.

Descriptions and classifications of the soil strata encountered and the results of the field and laboratory tests are given on the boring logs in Appendix B on Plates 2 through 10.

A key to the terms and symbols used on the boring logs is presented in Appendix B on

Plate 11. Generalized soil profiles are provided in Appendix D on Plates 15 and 16.

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The field tests performed included visual soil classifications and groundwater observations. The visual soil classifications are given on the boring logs. The groundwater table was not encountered by the boring terminal depths at the time of the onsite investigation. Groundwater in the form of perched water tables and saturated soils were encountered immediately above the basal rock formation in isolated boring locations. Perched water tables are common in the project area, particularly above the basal shale formation and within the weathered sandstone material.

LABORATORY TESTS

Laboratory tests were performed on soil samples recovered from the borings. The laboratory tests were directed at determining the engineering properties of the project soil and rock strata. The laboratory tests were conducted in accordance with the

American Society for Testing and Materials (ASTM) designations. The tests performed on samples from the borings included moisture content, dry unit weight, gradation, Atterberg Limits, and unconfined compression tests.

The natural soil moisture content was determined for the selected soil samples to provide a moisture profile for the borings. Gradation analyses were performed on representative soil samples to aid in the soil classification of the selected soil strata.

The gradation results are given on the summary of Laboratory Test Results at the end of this report. Atterberg Limits tests (liquid and plastic limits) were performed on selected samples to aid in the soil classification and to help evaluate the volume-change characteristics of each soil stratum. Unconfined compression tests were performed on selected samples for evaluation of the shear strength of the soil strata.

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The cohesive shear strengths of the soil samples are reported on the boring logs in tons per square foot (tsf) as the maximum observed compressive stress for soil.

Generally, the friable and weathered nature of the sampled sandstone and shale materials did not allow for adequate specimens for unit weight and unconfined testing.

Results of laboratory testing are provided on the boring logs and on the Laboratory Test

Results Summary in Appendix C on Plates 12 through 14.

SITE GEOLOGY

The project site is located in southwestern Benton County in Northwest Arkansas. The following soil types exist in the project area according to current USDA soil maps:

• Fayetteville Fine Sandy Loam – northern and eastern portions of the project area

• Enders Gravelly Loam – southern and western portions of the project area

The above-referenced soils in the project area have moderate-to-high potentials for corrosion of concrete and steel materials used in construction.

The project site is underlain with deposits of the Pennsylvanian Age Hale Formation and the Mississippian Age Fayetteville Formation. The Hale formation in the Fayetteville area consists of two members: the younger Prairie Grove, a massive and cross-bedded sandstone member, and the Cane Hill, a dark gray shale member. Both the Prairie

Grove and Cane Hill members were encountered in the boring. The boring terminal depths did not encounter the Fayetteville Shale formation, but this material is known to exist at greater depths in the project area. The depth of the Fayetteville Formation at the project site is not known but the depth is anticipated to be more than 100 feet thick in the project area based on previous investigations in the area.

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GENERAL SOIL CONDITIONS

The subsurface soil conditions at the site are described as below:

Existing Pavement Existing pavement was not encountered by the majority of the project borings. Borings B-2, B-3, B-4, B-5, B-7, and B-9 were conducted in areas with existing asphalt pavement. These borings encountered existing asphalt thicknesses that varied from 2.5 to 4.0 inches. The existing pavement was underlain by granular base course material that varied in thickness from six (6) to nine (9) inches.

Stratum I In the non-paved locations of Borings B-1, B-6, and B-8, a surface stratum of dark brown silty topsoil with vegetation/organics was encountered to a depth of six (6) inches at the boring locations. A topsoil thickness of up to twelve (12) inches is common in the project area and should be anticipated for project grading in non-paved areas.

Stratum II The borings generally encountered coarse-grained soils in the subgrade immediately beneath surface topsoil and pavement materials. The coarse-grained soils varied in classification between silty sand (SM), clayey sand (SC), and clayey gravel (GC). The sand and gravel portions of the Stratum II soils were generally weathered representations of sandstone and were encountered as dark brown and/or reddish-brown in color. The Stratum II soils exhibited very loose to very dense in-situ shear strengths with Standard Penetration Resistance values (N-values) ranging from 2 blows per foot to 50 blows with one (1) inch of advancement of the split spoon sampler. Lower blow-counts were recorded at depths with saturated moisture conditions within the Stratum II sandy soils. Void spaces are known to be present within the onsite sandstone material in areas where severe weathering has occurred from the constant presence of perched water tables. Depths where more competent sandstone lenses were encountered yielded very dense in-situ strengths.

Stratum III A stratum of weathered shale was encountered below the Stratum II material. The weathered shale material classified as fine-grained sandy silt (ML) and was encountered as brown to tan in color. The Stratum III material showed moderate signs of weathering and/or water staining. The weathered shale material exhibited medium-dense to very dense in-situ shear strength with recorded N-values ranging from 14 blows per foot to 50 blows with 5 inches of advancement of the sampler.

Stratum IV The basal stratum at the project location was encountered as medium-hard gray weathered shale material indicative of the Cane Hill Formation. The Stratum IV material is the recommended bearing stratum for micropiles on the project, if utilized. The shale material in the project area is known to become less weathered and more competent at greater depths.

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IBC Site Classification

The soil profile at this project site is a Site Class C according to Section 1613.5.2 of the

2012 International Building Code and current USGS information for the project area.

The site seismic classification determination may utilize spectral response accelerations

SDS and SD1 of 0.135g and 0.106g, respectively, with reference to Section 1613 of the

2015 International Building Code. The planned new facility is understood to fall under

Risk Category II with regards to seismic design.

Fine-Grained Soil Analysis

The fine fraction of the fine-grained silt (ML) material has a low plasticity and a low potential for volumetric changes due to changes in the soil moisture content. The Liquid

Limit (LL) of the ML soils varied from non-plastic to 42 and the Plasticity Index (PI) of those soils ranged from non-plastic to 15. The fine fraction of the ML material makes up between 57 and 61 percent of the ML soil mass as indicated by the results of gradation analyses from the borings.

The fine fraction of the fine-grained sandy lean clay (CL) material has a low-to-moderate plasticity and a moderate potential for volumetric changes due to changes in the soil moisture content. The LL of the CL soils was determined to be 42 and the PI of those soils was 25. The fine fraction of the CL material makes up approximately 50 percent of the CL soil mass as indicated by the results of gradation analyses from the borings.

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The fine fraction of the fine-grained elastic silt (MH) material has a moderate-to-high plasticity and a high potential for volumetric changes due to changes in the soil moisture content. The LL of the MH soils was determined to be 71, and the PI of those soils was 19. The fine fraction of the MH material makes up approximately 74 percent of the MH soil mass as indicated by the results of gradation analyses from the borings.

The fine fraction of the coarse-grained silty sand (SM) materials was determined to be non-plastic. The fine fraction of the SM materials makes up between 14 and 45 percent of the SM masses as indicated by the results of gradation analyses from the borings.

The fine fraction of the coarse-grained clayey sand (SC) and clayey gravel (GC) materials has a low-to-moderate plasticity and a low potential for volumetric changes due to changes in the soil moisture content. The LL of the SC and GC soils varied from

29 to 44 and the PI of those soils ranged from 11 to 25. The fine fraction of the SC and

GC materials makes up between 28 and 48 percent of the SC and GC soil masses as indicated by the results of gradation analyses from the borings.

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ANALYSIS AND RECOMMENDATIONS:

Site Preparation and Grading

The existing pavement and surface Stratum I topsoil materials should be removed from beneath all building dimensions. Topsoil should also be removed from beneath planned new pavement dimensions. The Stratum I soils are considered moisture-sensitive and may lose significant strength upon disturbance and/or saturation, resulting in differential settlement of foundations and subgrade failures beneath pavement. It is anticipated that an average depth of twelve (12) inches will need to be stripped during initial site grading. Actual stripping depth recommendations should be achieved during construction by proof-rolling as described in the following sections of this report.

Additional care should be taken by the Contractor to prevent excessive saturation of exposed Stratum II subgrade soils. While the Stratum II materials are more resilient towards influence from moisture, they will likely still lose significant strength upon saturation. Protection of these soils can be achieved by providing positive drainage during construction and/or covering with select fill material soon after excavation, where applicable. The Stratum II soils will be especially susceptible to reduced shear strengths if construction occurs during historically wet portions of the calendar year.

Excavated slopes during construction should be benched or sloped to provide a minimum two-to-one horizontal-to-vertical (2H:1V) ratio. Construction slopes steeper than recommended may be unstable, particularly when introduced to moisture increases during precipitation events. Temporary shoring measures should be anticipated to stabilize construction slopes that are steeper than 2H:1V.

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General Structure Foundation Recommendations

The foundations relevant to the project structure should be sized to meet three (3) conditions. First, the maximum stresses imposed on the foundation strata should not exceed the allowable bearing pressures as determined from the shear strength properties of the bearing strata. Secondly, foundations should be designed to limit the maximum anticipated total and differential settlement to magnitudes that will neither damage nor impair the use of the structures. Finally, the foundation system must also be designed to resist the anticipated lateral or overturning forces during the most critical loading conditions, including earthquake loadings. These factors, as well as construction considerations related to the existing soil and ground conditions, were influential in preparation of the recommendations presented hereinafter.

All foundation excavations should be cleaned of loose soil, debris, and water prior to the placement of reinforcing elements and concrete. Foundation excavations should be observed by the Geotechnical Engineer or their representative to verify the stability of exposed soils, prior to placement of fill material, reinforcing elements, or concrete.

Concrete should not be placed on frozen soil. Adequate control joints within any building structural walls should be used to control settlement that may occur between the footings.

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Building Foundation Recommendations: Shallow Foundations

The foundation system recommended for the new inpatient facility structure is a shallow foundation system composed of continuous and individual (spread) foundations. The shallow foundations should be placed in the stable Stratum II soils. Structure foundations should not bear on a combination of native and fill materials or on a combination of soil and rock materials as these conditions may induce differential settlement amounts in excess of those provided by this report. If rock is exposed at planned foundation bearing elevations, it should be excavated so that a minimum of one (1) foot of properly placed and compacted select fill material can be installed beneath the foundation dimensions. The select fill material should be installed as described in the Select Fill Material section of the report (Pages 19-20).

Table 2 on the following page references the minimum elevations at each conducted boring location to anticipated stable subgrade soils suitable for bearing structure foundations as referenced by this report. Stable soils were generally encountered between two (2) and three (3) feet below existing ground elevations across the site.

Actual bearing elevations may vary from those referenced by Table 2 and should be verified during construction.

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TABLE 2: Minimum Anticipated Elevations to Stable Subgrade Material

Boring Number Ground Elevation Anticipated Elevation of Stable Bearing Material

B-1 1466.0 1464.0

B-2 1466.7 1464.7

B-3 1466.3 1463.3

B-4 1468.9 1465.9

B-5 1469.5 1464.5

B-6 1473.4 1468.0

Note: Ground elevations shown in Table 2 are rounded to the nearest 0.1 foot.

Shallow foundations for the new inpatient mental health facility that are placed on stable subgrade soils may utilize design net allowable bearing capacities of 2,000 pounds per square foot (psf) for continuous foundations and 2,500 psf for spread or individual foundations. The allowable bearing capacities provide a minimum factor of safety of three (3) and were calculated using a minimum footing width of two (2) feet, a minimum footing thickness of one (1) foot, and a minimum footing depth of two (2) feet below exterior ground elevations, which is sufficient to prevent against frost heave in the project area.

Total long-term foundation settlement for footings in the recommended soils with the assumed dimensions and loading is anticipated to be approximately ½-inch and differential settlement between footings is anticipated to be in the order of ¼-inch maximum between individual footings or along 40-feet of footing lengths.

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A significant zone of loose soils was encountered by Boring B-6 from 15 to 25 feet below the existing ground elevation of 1473.4. Due to the presence of this soft zone beginning near elevation 1458.5, it is our recommendation that the foundations for the northeast portion of the building near the area of B-6 are placed at the highest bearing elevation achievable. We understand that design constraints such as FFE’s of existing surrounding buildings and walkways control the FFE in that area to 1467.3. To reduce the influence of foundation loading into the depths of the soft soil zone, we recommend that the northeast portion of the building be placed primarily on spread foundations and that the foundation bearing elevation in this area does not occur below elevation

1465.5. With the anticipated planned cut in the northeast building area, it is likely that the FFE will be sufficiently below surrounding grades in the area of Boring B-6 to protect against frost heave, particularly if a bearing elevation is possible above 1465.5.

The above conditions with the anticipated loading based on provided bearing capacities would yield vertical effective stresses of approximately 20 psf at or below elevation

1455.5 for continuous and spread foundations.

Retaining wall foundations may utilize the bearing capacity and settlement values and recommendations found previously in this section.

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Building Foundation Recommendations: Micropile Foundations

As an alternative if structure loading exceeds those previously described or if foundations in the area of Boring B-6 cannot be designed as recommended, the building additions may be supported on a deep foundation system consisting of micropiles. The design of the micropile foundation system may use the values provided by Table 3 below, the boring logs in Appendix B, laboratory testing results found in

Appendix C, and the soil profiles in Appendix D. The design and performance criteria for these foundation systems are typically provided by the installation Contractor.

Hayward-Baker, Foundation Specialties, Inc., and Geopier Foundation Company are examples of contractors that provide these foundation systems within the region.

Micropiles will provide additional lateral stability for the structure by drilling into the rock formation, which is an advantage over alternative piles such as helical piles. The competent Stratum IV shale stratum was generally encountered between elevations

1427.0 and 1437.0 across the site.

TABLE 3: Onsite Soil Structural Properties

STRATUM II STRATUM III STRATUM IV

FRICTION ANGLE

(ϕ)

25° 20° 30°

AVG. DRY UNIT

WEIGHT (pcf)

95 105 130

Allowable Skin Friction - Compression (ksf)

2.0 1.5 3.0

Allowable Skin Friction - Tension (ksf)

1.0 1.5 2.0

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Skin friction calculations should negate the Stratum I soils and the top five (5) feet of the micropile length, regardless of the subgrade material. The design should neglect lateral forces in the upper two (2) feet of the micropiles. Beginning two (2) feet below the top-of-pile elevation, a lateral pressure of 250 psf should be anticipated with linear increase to a maximum of 2,000 psf as depth increases.

Statement Regarding Drilled Pier Foundations

Additional recommendations for drilled pier and grade beam foundations may be provided upon request. The recommendations would consist of a minimum three (3) feet rock socket into the Stratum IV shale formation with an end-bearing capacity of

18,000 psf. The drilled piers would be recommended to maintain a minimum length-to-diameter ratio of 3L:1D, respectively. We do not recommend the drilled pier system as a feasible option due to the measures likely required for installation. The highly weathered and saturated portions of the Stratum II sandstone materials can often develop into void-like spaces that would require temporary casing for concrete placement in the drilled pier dimensions. This is often a cost-prohibitive project feature as was encountered with the last major building addition at the north end of the VA campus.

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Groundwater – Site Dewatering

The groundwater table was not encountered by the boring terminal depths at the time of the onsite investigation. Groundwater in the form of perched water tables and saturated zones were encountered immediately above the basal rock formation in isolated boring locations, generally at depths with highly-weathered sandstone materials. Water observations were made by the drill crew during drilling operations and at the completion of drilling each boring. The installation and periodic measurement of monitoring wells would be required to establish seasonal piezometric surfaces below this project site. Based on previous knowledge at the existing VA facility, significant saturated void-like zones are present beneath the site within the weathered sandstone formation, particularly at deeper elevations near the transition into the basal shale stratum.

Building Slab-on-Grade

It is anticipated that the new inpatient mental health facility construction will consist of a slab-on-grade with an FFE of 1467.3. A building slab-on-grade may be utilized providing a minimum four (4) inches cushion of sand, crushed stone, or gravel is placed below the slab with a vapor barrier immediately below the concrete. The Stratum I soils at the project site are considered moisture-sensitive and unsuitable to directly support slabs-on-grade. Existing asphalt pavement and underlying base course material should also be removed from beneath planned slab dimensions.

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Across the southern half of the building, an average of one (1) foot of select fill material should be anticipated beneath the building slab-on-grade. Across the northern half of the building where planned cut amounts are two (2) feet or greater, stable subgrade material is anticipated being exposed through planned project grading operations.

Specific project undercut depths, subgrade recommendations, and stable soils should be verified onsite by proof-rolling as described below.

Following stripping and cutting and prior to fill placement, the structure’s slab subgrade footprint should be proof-rolled with a tandem-axle fully-loaded dump truck weighing approximately 60,000 pounds, or equivalent construction equipment. The proof-rolling should be observed by the Geotechnical Engineer or their representative to verify stable subgrade conditions. Any soft and/or yielding subgrade areas encountered should be repaired by undercutting and backfilling with select fill material as recommended. If proof-rolling is not feasible due to project grading, alternative methods of verifying stable subgrade soils may be utilized under the direction of the Geotechnical Engineer.

Select fill material should be placed as described in the Select Fill Material section of this report (Pages 19-20). Thickened lifts of select fill material should not be utilized within the building footprint or within the zone-of-influence dimensions relevant to structure foundations.

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Site Retaining Structures – Lateral Earth Pressures

It is anticipated that the project will include a retaining wall in the courtyard area and may also include other site features which include below-grade walls. The referenced retaining structures should be designed to resist the minimum equivalent fluid weights provided in Table 4 below. The recommended minimum factor of safety against sliding and overturning is 1.5 and 2.0 respectively. The provided lateral earth pressures assume a drained condition for the backfill material. To achieve this, the retaining structures should be backfilled using a free-draining granular material and be provided with thru-wall drains or a gravity trench drain system graded to daylight for the release of any hydrostatic pressure which may develop. The values provided by Table 4 for No.

57 or No. 67 crushed stone gravel assume a 1H:1V maximum backfill slope from the heel of the retaining wall foundation. If a vertical “chimney drain” is provided by the No.

57 or No. 67 stone, then the values for select fill material or onsite soils should be used depending on relevancy towards the material behind the gravel.

TABLE 4: Lateral Earth Pressure Design Values

Soil/Backfill Type

Moist Unit Weight

(pcf)

Friction Angle, φ (°)

Equivalent Fluid Pressure (pcf)

Active Passive At-Rest

Select Fill Material (GC or GM)

120 28 43 332 64

Onsite Soils (Stratum II) 120 25 49 296 69

Onsite Soils (Stratum III) 125 20 61 255 82

No. 57 or No. 67 Stone

85 35 23 314 37

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A coefficient of friction of 0.40 may be used provided the retaining structure is supported on a minimum of four (4) inches of placed and compacted Class 7 Base

Course material. A friction value of 0.35 may be used provide the retaining structures is supported directly on select fill material or native soils.

Select Fill Material

Any select fill material required for the project is recommended to be an off-site borrow material of locally available reddish-brown silty or clayey chert gravel meeting Unified

Soils Classification as a GC or GM material and having a Plasticity Index of 30 or less, a Liquid Limit of 55 or less, a minimum of 30% retained on the ¾-inch sieve, and a maximum of 35% passing the No. 200 sieve. Onsite materials meeting the requirements detailed in this report for “Select Fill” may be used. Any material to be used as select fill on the project should be reviewed and approved by the Geotechnical

Engineer.

Select fill material should be placed in maximum eight (8) inch compacted lifts at a minimum density of 98 percent of the maximum dry density as determined by the

Standard Proctor Test, ASTM D 698 and within three (3) percent of optimum moisture.

All fill and backfill should be placed in horizontal lifts. When placing fill next to existing slopes, the slope face should be stripped of all vegetation and the face “benched” to allow placement of horizontal lifts and bonding to the slope face.

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The use of thickened lifts to a maximum thickness of twenty-four (24) inches is permitted in new pavement areas to prevent further undercutting beneath planned finish subgrade elevations. Thickened lifts of select fill material should not be utilized within the building footprint, beneath building foundations, or within the zone-of-influence dimensions relevant to structure foundations. Thickened lifts should not be placed to reach finish subgrade in pavement areas. A minimum of one (1) standard lift should be placed above any thickened lift utilized below new pavement.

Rock Excavation

Rock removal techniques will be required to excavate foundations or utilities below project elevations at boring locations where "Auger Refusal" is referenced on the boring logs. Additionally, rock removal techniques should be anticipated for excavations at depth where 50 blow-counts are referenced in the Stratum II sandstone material. The onsite rock materials exist as medium-hard shale and weathered sandstone which will each require equipment attachments such as hammer-hoes or ripper teeth to excavate during the project. Utility excavations within these materials should be particularly planned and budgeted.

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New Pavement Areas

It is our understanding that new pavement areas are to exist in the area of Boring B-8 to the west of the existing parking lot and to the southwest of the planned new inpatient facility. After initial site grading, subgrade preparation and proof-rolling should follow the same procedure as previously described in the Building Slab-on-Grade section of the report (Pages 16-17). Select fill material under planned pavement areas should be placed as previously described in the Select Fill Material section of the report (Pages

19-20). It is anticipated that an average of eighteen (18) inches of select fill material will be required for stabilization beneath planned pavement areas with reference to existing ground elevations. A thickness of up to two (2) feet of select fill material may be required in isolated areas to stabilize the pavement subgrade.

Minimum Project Pavement Recommendations

The following pavement recommendations are based on stable subgrade material and/or select fill material existing beneath planned pavement sections. This requirement would be provided by proper placement of approved select fill material and/or stable onsite material being verified by proof-rolling within the pavement subgrade dimensions. Minimum project pavement sections in new pavement areas are recommended to be as shown in Table 4 on the following page.

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Table 4: Minimum Recommended Project Pavement Sections

Standard Duty Heavy Duty C o n cr e v e m e n t Portland Cement Concrete 4" 6"

Class 7 Base Course (95% MPD) 6" 10"

Stable Subgrade or Compacted Select Fill (98% SPD) As Required As Required

A sp h lt v e m e n t ACHM Surface Course (1/2") 3" 3"

ACHM Binder Course (1") N/A 3"

Class 7 Base Course (95% MPD) 8" 12"

Stable Subgrade or Compacted Select Fill (98% SPD) As Required As Required

It is our recommendation that areas with a high density of truck traffic such as loading dock or trash enclosure areas should follow the requirements for heavy duty concrete pavement.

Quality Control testing of the earthwork operation, concrete, paving and other phases is recommended to be utilized during construction to assure the Engineer and Owner that the construction complies with the specifications. All trenching and excavation should be conducted in accordance with Arkansas State Law and OSHA guidelines and requirements.

APPENDIX A:

BORING LAYOUT

S.H.

FY172108

MAR. 2017L.E.W.

AS NOTED

BORING PLAN

VA INPATIENT

MENTAL HEALTH BUILDING,

FAYETTEVILLE, ARKANSAS

2017C

1810 N. College

Fayetteville, Arkansas 72702

PH# 479.443.2377

Fax # 479.443.9241

900 West Markham

Little Rock, Arkansas 72201

PH# 501.371.0272

Fax # 501.371.9932

4606 S. Garnett Rd, Ste 401

Tulsa, Oklahoma 74146

PH# 918.619.6803

Michael Roth and

Associates

APPENDIX B:

BORING LOGS

50/7

50/1

50/7

SM

SM

DARK BROWN SILTY TOPSOIL

DARK BROWN TO REDDISH-BROWN SILTY SAND;

Very Loose; Trace Coarse and Medium Sands; Some Fine Sand; Trace Fine Gravel

(DENSE FROM 2 TO 8 FEET)

REDDISH-BROWN SILTY SAND WITH GRAVEL;

Very Dense; Weathered Sandstone; Trace Coarse and

Medium Sands; Some Fine Sand; Little Fine Gravel

(MEDIUM-DENSE FROM 15 TO 20 FEET)

DARK BROWN SILTY SAND;

Loose; Weathered Sandstone; Trace Coarse and Medium

Sands; Some Fine Sand; Trace Fine Gravel

DARK BROWN TO TAN SANDY SILT; Very Dense

**AUGER REFUSAL AT 26.5 FEET**

END OF BORING

19.6 12.8

15.2

14.1

17.6

15.0

9.3

23.9

35.9

17.3

NP

NP

NP

27.3

22.4

34.5

LOG OF BORING NUMBER B - 1

DESCRIPTION: VA Inpatient Mental Health Center PROJECT NUMBER: FY172108

DATE DRILLED: 3/27/2017

LOCATION: Fayetteville, AR PROJECT ENGINEER: Steven J. Head, P.E.

PROJECT OWNER: Michael Roth and Associates BORING LOCATION: See Plate 1 DRILLING METHOD: 6 1/2" Hollow Stem Auger ELEVATION: 1466.0

Completion Depth: 26.5 feet Depth to Water: DRY Logged By: J. Thomas

D ep th

F ee t)

E le va ti o n

F ee t)

S am p le

N o

B lo w s/

F o o t

S o il L eg en d

U S

C S

T yp e Description of Material (Color, Type, Moisture, and Consistency)

M o is tu re

L iq u id

L im it

P la st ic

L im it

P la st ic it y

In d ex

P

L ab

Q u

T

S F

F ie ld Q u

T S

F

D ry

D en si ty p cf

PLATE 2

T h is in fo rm at io n p er ta in s o n ly t o t h is b o ri n g a n d s h o u ld n o t b e in te rp re te d a s b ei n g in d ic at iv e o f th e si

50/3

50/6

50/7

50/7

50/9

50/0

CL

SM

SM

ML

MH

ML

3" OF ASPHALT PAVING

6" OF COARSE AGGREGATE BASE

REDDISH-BROWN SANDY LEAN CLAY;

Soft; Trace Coarse and Medium Sands; Some Fine Sand;

Trace Fine Gravel

REDDISH-BROWN SILTY SAND WITH GRAVEL;

Very Dense; Weathered Sandstone; Trace Coarse and Medium Sands; Some Fine Sand; Little Fine Gravel

DARK BROWN TO REDDISH-BROWN SILTY SAND;

Highly Weathered Sandstone; Dense; Trace Coarse and

Medium Sands; Some Fine Sand; Trace Fine Gravel

(MEDIUM-DENSE FROM 20 TO 25 FEET)

DARK BROWN TO TAN SILTY CLAY WITH SAND;

Highly Weathered Shale; Very Stiff

DARK REDDISH-BROWN ELASTIC SILT WITH SAND;

Weathered Sandstone; Very Loose; Saturated; Trace

Medium Sand; Little Fine Sand

DARK BROWN TO TAN SILTY CLAY WITH SAND;

Highly Weathered Shale; Very Stiff

**AUGER REFUSAL AT 36.5 FEET**

TAN TO GRAY HIGHLY WEATHERED SHALE WITH

SANDSTONE INTERBEDDING;

Laminated Structure

(36.5 to 43 feet) 28% Recovery

0% RQD

END OF BORING

21.3

12.1

8.7

11.7

8.8

19.5

27.4

21.7

57.1

NP

NP

50.4

14.2

32.9

74.3

LOG OF BORING NUMBER B - 2

DESCRIPTION: VA Inpatient Mental Health Center PROJECT NUMBER: FY172108

DATE DRILLED: 3/22/2017

LOCATION: Fayetteville, AR PROJECT ENGINEER: Steven J. Head, P.E.

PROJECT OWNER: Michael Roth and Associates BORING LOCATION: See Plate 1 DRILLING METHOD: 6 1/2" Hollow Stem Auger & 3" NX Bit ELEVATION: 1466.74

Completion Depth: 43.0 feet Depth to Water: 35 FEET Logged By: J. Thomas

D ep th

F ee t)

E le va ti o n

F ee t)

S am p le

N o

B lo w s/

F o o t

S o il L eg en d

U S

C S

T yp e Description of Material (Color, Type, Moisture, and Consistency)

M o is tu re

L iq u id

L im it

P la st ic

L im it

P la st ic it y

In d ex

P

L ab

Q u

T

S F

F ie ld Q u

T S

F

D ry

D en si ty p cf

PLATE 3

T h is in fo rm at io n p er ta in s o n ly t o t h is b o ri n g a n d s h o u ld n o t b e in te rp re te d a s b ei n g in d ic at iv e o f th e si

50/3

50/3

50/3

50/7

SC

SM

ML

2.5" OF ASPHALT PAVING

8" OF COARSE AGGREGATE BASE

REDDISH-BROWN CLAYEY SAND;

Loose; Trace Coarse and Medium Sands; Some Fine Sand; Trace Fine Gravel

REDDISH-BROWN SILTY SAND;

Highly Weathered Sandstone; Very Dense; Trace Coarse and Medium Sands; Some Fine Sand; Trace Fine Gravel

DARK BROWN TO REDDISH-BROWN SILTY SAND;

Weathered Sandstone; Dense

DARK BROWN TO TAN SANDY SILT;

Highly Weathered Shale; Very Stiff; Trace Coarse; Little

Medium and Fine Sands; Trace Fine Gravel

**AUGER REFUSAL AT 26.5 FEET**

TAN TO GRAY HIGHLY WEATHERED SANDSTONE

(26.5 to 30 feet) 30% Recovery

0% RQD

TAN TO GRAY HIGHLY WEATHERED SHALE WITH

SANDSTONE INTERBEDDING;

Laminated Structure

(30 to 41.5 feet) 5% Recovery

0% RQD

DARK GRAY WEATHERED SHALE;

Laminated Structure

(41 to 46.5 feet) 20% Recovery

0% RQD

END OF BORING

3.3

18.7

23.2

10.0

8.1

10.4

28.0

17.6

NP

NP

48.1

19.9

19.4

61.1

LOG OF BORING NUMBER B - 3

DESCRIPTION: VA Inpatient Mental Health Center PROJECT NUMBER: FY172108

DATE DRILLED: 3/21/2017

LOCATION: Fayetteville, AR PROJECT ENGINEER: Steven J. Head, P.E.

PROJECT OWNER: Michael Roth and Associates BORING LOCATION: See Plate 1 DRILLING METHOD: 6 1/2" Hollow Stem Auger & 3" NX Bit ELEVATION: 1466.30

Completion Depth: 46.5 feet Depth to Water: DRY Logged By: J. Thomas

D ep th

F ee t)

E le va ti o n

F ee t)

S am p le

N o

B lo w s/

F o o t

S o il L eg en d

U S

C S

T yp e Description of Material (Color, Type, Moisture, and Consistency)

M o is tu re

L iq u id

L im it

P la st ic

L im it

P la st ic it y

In d ex

P

L ab

Q u

T

S F

F ie ld Q u

T S

F

D ry

D en si ty p cf

PLATE 4

T h is in fo rm at io n p er ta in s o n ly t o t h is b o ri n g a n d s h o u ld n o t b e in te rp re te d a s b ei n g in d ic at iv e o f th e si

50/3

50/3

50/3

50/5

SC

SM

ML

3" OF ASPHALT PAVING

9" OF COARSE AGGREGATE BASE

REDDISH-BROWN CLAYEY SAND;

Medium Dense

DARK BROWN TO REDDISH-BROWN SILTY SAND;

Very Dense; Trace Coarse and Medium Sands; Some Fine

Sand; Trace Fine Gravel

DARK BROWN SILTY SAND;

Highly Weathered Sandstone; Dense; Trace Coarse and

Medium Sands; Some Fine Sand; Trace Fine Gravel

DARK BROWN TO TAN SANDY SILT; Highly Weathered Shale; Stiff; Trace Medium Sand; Some Fine Sand

**AUGER REFUSAL AT 26.5 FEET**

END OF BORING

23.5

10.2

11.8

5.9

8.4

23.6

25.6

34.4

NP

NP

NP

19.2

45.4

57.1

0.72 97.4

LOG OF BORING NUMBER B - 4

DESCRIPTION: VA Inpatient Mental Health Center PROJECT NUMBER: FY172108

DATE DRILLED: 3/29/2017

LOCATION: Fayetteville, AR PROJECT ENGINEER: Steven J. Head, P.E.

PROJECT OWNER: Michael Roth and Associates BORING LOCATION: See Plate 1 DRILLING METHOD: 6 1/2" Hollow Stem Auger ELEVATION: 1468.87

Completion Depth: 26.5 feet Depth to Water: DRY Logged By: J. Thomas

D ep th

F ee t)

E le va ti o n

F ee t)

S am p le

N o

B lo w s/

F o o t

S o il L eg en d

U S

C S

T yp e Description of Material (Color, Type, Moisture, and Consistency)

M o is tu re

L iq u id

L im it

P la st ic

L im it

P la st ic it y

In d ex

P

L ab

Q u

T

S F

F ie ld Q u

T S

F

D ry

D en si ty p cf

PLATE 5

T h is in fo rm at io n p er ta in s o n ly t o t h is b o ri n g a n d s h o u ld n o t b e in te rp re te d a s b ei n g in d ic at iv e o f th e si

50/7

50/2

GC

SM

3" OF ASPHALT PAVING

9" OF COARSE AGGREGATE BASE

DARK BROWN TO REDDISH-BROWN

CLAYEY GRAVEL WITH SAND;

Loose; Trace Coarse and Medium Sands; Some Fine Sand; Trace Coarse Gravel; Some Fine Gravel

(VERY DENSE FROM 5 TO 7 FEET)

(MEDIUM-DENSE FROM 7 TO 10 FEET)

DARK BROWN TO REDDISH-BROWN SILTY SAND;

Weathered Sandstone; Trace Coarse and Medium Sands;

Some Fine Sand; Trace Fine Gravel

**AUGER REFUSAL AT 17 FEET**

END OF BORING

25.5

28.8

20.6

19.9

20.9

13.2

44 19 25

NP

27.6

25.0

LOG OF BORING NUMBER B - 5

DESCRIPTION: VA Inpatient Mental Health Center PROJECT NUMBER: FY172108

DATE DRILLED: 3/28/2017

LOCATION: Fayetteville, AR PROJECT ENGINEER: Steven J. Head, P.E.

PROJECT OWNER: Michael Roth and Associates BORING LOCATION: See Plate 1 DRILLING METHOD: 6 1/2" Hollow Stem Auger ELEVATION: 1469.47

Completion Depth: 17.0 feet Depth to Water: DRY Logged By: J. Thomas

D ep th

F ee t)

E le va ti o n

F ee t)

S am p le

N o

B lo w s/

F o o t

S o il L eg en d

U S

C S

T yp e Description of Material (Color, Type, Moisture, and Consistency)

M o is tu re

L iq u id

L im it

P la st ic

L im it

P la st ic it y

In d ex

P

L ab

Q u

T

S F

F ie ld Q u

T S

F

D ry

D en si ty p cf

PLATE 6

T h is in fo rm at io n p er ta in s o n ly t o t h is b o ri n g a n d s h o u ld n o t b e in…