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ECS Southeast, LLP Preliminary Geotechnical Engineering Report George Boyd Road Property George Boyd Road Ashland City, Tennessee ECS Project Number 26:3774 April 10, 2019

April 10, 2019 Mr. Kerry McCarver Cheatham County Government 100 Public Square, Suite 115 Ashland City, TN 37015

ECS Project No. 26:3774 Reference: Preliminary Geotechnical Engineering Report

George Boyd Road Property George Boyd Road Ashland City, Tennessee

Dear Mr. McCarver: ECS Southeast, LLP (ECS) has completed the preliminary subsurface exploration for the above-referenced project. Our services were performed in general accordance with our Proposal No. 26-6345 dated March 27, 2019. This report presents our preliminary understanding of the geotechnical aspects of the project, the results of the field exploration and laboratory testing conducted, and our preliminary design and construction recommendations. It has been our pleasure to be of service to Cheatham County Government during the design phase of this project. We would appreciate the opportunity to remain involved during the continuation of the design phase and would like to provide our services during construction operations as well to verify the assumptions of subsurface conditions made for this report. Should you have any questions concerning the information contained in this report, or if we can be of further assistance to you, please contact us. Respectfully submitted, ECS Southeast, LLP Mark Van Aken, G.I.T. Project Manager [email protected] Eric M. Gasiecki, P.E. Mark D. Luskin, P.E., P.G. Geotechnical Department Manager Branch Manager [email protected] [email protected]

mailto:[email protected]

mailto:[email protected]

George Boyd Road Property April 10, 2019 ECS Project No. 26:3774 Page i

TABLE OF CONTENTS

EXECUTIVE SUMMARY ............................................................................................................. 1 1.0 INTRODUCTION .................................................................................................................. 2

1.1 General ................................................................................................................................... 2 1.2 Scope of Services .................................................................................................................... 2

2.0 PROJECT INFORMATION ..................................................................................................... 3 2.1 Project Location...................................................................................................................... 3 2.2 Proposed Construction ........................................................................................................... 4

2.2.1 Site Civil Features .......................................................................................................... 4 2.2.2 Structural Information/Loads ....................................................................................... 4

3.0 FIELD EXPLORATION ........................................................................................................... 5 3.1 Field Exploration Program ...................................................................................................... 5

3.1.1 Test Borings .................................................................................................................. 5 3.1.2 Electric Resistivity (ER) Survey ...................................................................................... 5 3.1.3 Laboratory Testing Program ......................................................................................... 6

3.2 Regional/Site Geology ............................................................................................................ 7 3.3 Subsurface Characterization .................................................................................................. 7 3.4 Laboratory Test Results .......................................................................................................... 9 3.5 Groundwater Observations .................................................................................................... 9 3.6 Electrical Resitivity (ER) Survey .............................................................................................. 9

4.0 DESIGN RECOMMENDATIONS ........................................................................................... 13 4.1 General ................................................................................................................................. 13 4.2 Subgrade Preparation .......................................................................................................... 13

4.2.1 Sinkhole Considerations ............................................................................................. 14 4.2.2 Stripping and Grubbing ............................................................................................... 15 4.2.3 Proofrolling ................................................................................................................. 15

4.3 Earthwork Operations .......................................................................................................... 16 4.3.1 Structural fill Materials ............................................................................................... 16 4.3.2 Compaction ................................................................................................................. 18

4.4 Utility Installations ............................................................................................................... 19 4.5 Building Design ..................................................................................................................... 19

4.5.1 Foundations ................................................................................................................ 19 4.5.2 Floor Slabs ................................................................................................................... 21 4.5.3 Seismic Design Considerations ................................................................................... 22

4.6 Site Design Considerations ................................................................................................... 23 4.6.1 Slope Evaluations and Stability Analyses .................................................................... 23 4.6.2 Pavement Sections ..................................................................................................... 23 4.6.3 Pavement Maintenance .............................................................................................. 25

4.7 General Construction Considerations .................................................................................. 25 5.0 CLOSING ........................................................................................................................... 27

George Boyd Road Property April 10, 2019 ECS Project No. 26:3774 Page ii

APPENDICES Appendix A – Drawings & Reports

• Site Vicinity Diagram • Exploration Location Diagram

Appendix B – Field Operations • Reference Notes for Boring Logs • Boring Logs B-1 through B-5 • ER Survey Lines (Line 1 through Line 6)

Appendix C – Laboratory Testing • Laboratory Testing Summary

Appendix D – Supplemental Report Documents • Seismic Design Map • Important Information

George Boyd Road Property April 10, 2019 ECS Project No. 26:3774 Page 1

EXECUTIVE SUMMARY

ECS Southeast, LLP (ECS) has completed the preliminary subsurface exploration to provide an evaluation of subsurface conditions, including the identification of potential undocumented fill materials or buried debris, at the former sawmill located on George Boyd Road in Ashland City, Tennessee. The project information summarized below is based exclusively on the information made available to us by the client at the time of this report and the results of our subsurface exploration. Our findings, conclusions, and recommendations are summarized below. PROJECT INFORMATION:

• Site Location : George Boyd Road, Ashland City, Tennessee • Building Scope: Former Sawmill – Proposed Highway Department Facility • Building Type: Assumed shallow foundations, slab-on-grade, masonry walls • Assumed Loads: Assumed max. column loads = 150 kips, Max. wall loads = 3 to 5

klf • Earthwork: Less than +/- 15 feet of cut/fill anticipated • Sitework: Assumed parking lot, drive lanes, and underground utilities

SUBSURFACE CONDITIONS: • Field Exploration: 5 SPT borings in the proposed development areas

6 ER Survey Lines • Surface Material: Gravel (Borings B-2, B-4, and B-5) = approximately 1- to 8-inches • Existing Fill: Encountered in Borings B-2 and B-4 • Natural Material: Encountered at all boring locations • Refusal Materials: Encountered in Borings B-3 and B-5 • Groundwater: Not encountered

GEOTECHNICAL CONCERNS:

• Presence of undocumented fill • Presence of possible karts conditions • Presence of potentially highly expansive clays

PRELIMINARY DESIGN & CONSTRUCTION RECOMMENDATIONS:

• Shallow foundations: Max. Net Allow. Bearing Pressure See foundation section Min. Exterior (Unheated) Embedment = 18 inches Min. Interior (Heated) Embedment = Per structural design

• Slabs-on-Grade: Modulus of Subgrade Reaction, k = 110 pci • Seismic Design: Seismic Design Category “D”

This summary should not be considered apart from the entire text of the report with all the qualifications and considerations mentioned herein. Details of our conclusions and recommendations are discussed in the report text.


1.0 INTRODUCTION

1.1 GENERAL

The preliminary recommendations developed for this report are based on project information supplied by Rufus Johnson Associates. This preliminary report contains the results of our subsurface exploration and laboratory testing programs, site characterization, engineering analyses, and recommendations for the design and construction of the planned building and pavements. 1.2 SCOPE OF SERVICES To obtain the necessary geotechnical information required for design of the proposed construction, five (5) soil test borings and six (6) Electric Resistivity (ER) lines were performed at locations selected by ECS. These borings and ER survey lines were located at the approximate locations shown on Figure 2 in Appendix A. A laboratory-testing program was also implemented to characterize the physical and engineering properties of the subsurface soils. This report discusses our exploratory and testing procedures, presents our preliminary findings and evaluations and includes the following:

• A brief review and description of our field and laboratory test procedures and the results of testing conducted.

• A review of surface topographical features and site conditions. • A review of area and site geologic conditions. • A review of subsurface soil stratigraphy with pertinent available physical properties. • Final copies of our SPT boring logs. • Recommendations for site preparation and construction of compacted fills, including an

evaluation of on-site soils for use as compacted fills and approximate delineation of potentially unsuitable soils.

• Preliminary recommendations for foundation design and construction. • Preliminary recommended cut and fill slope design criteria. • Preliminary recommendations for pavement design, based on an assumed CBR value. • An evaluation of soil and rock excavation issues. • Preliminary recommendations for slab-on-grade construction. • Preliminary recommendations for seismic site classification.


2.0 PROJECT INFORMATION

2.1 PROJECT LOCATION

The project site is located on George Boyd Road approximately 1,200 feet northwest of the intersection with Bearwallow Road in Ashland City, Tennessee. The site is bound by George Boyd Road to the east and undeveloped land to the north, south, and west. Based on elevations obtained from a USGS topographic map, the site appears to undergo approximately 20 feet of topographic relief.

Figure 2.1.1 Site Location


2.2 PROPOSED CONSTRUCTION

The proposed project will provide an evaluation of subsurface conditions, including the identification of potential undocumented fill materials or buried debris, at the former sawmill. 2.2.1 Site Civil Features

• Assumed grading for roads, parking lots, building pad, special features 2.2.2 Structural Information/Loads The following information presents our understanding of the structure and loads:

Table 2.2.2.1 Design Values

SUBJECT DESIGN INFORMATION / EXPECTATIONS Building Footprint Unknown at this time # of Stories Unknown at this time Usage Former Sawmill – Proposed Highway Department Facility Assumed Maximum Column Loads

150 kips

Assumed Maximum Wall Loads

3 to 5 kips per linear foot

Provided Lowest Finish Floor Elevation

Not provided


3.0 FIELD EXPLORATION

3.1 FIELD EXPLORATION PROGRAM

The field exploration was planned with the objective of characterizing the project site in general geotechnical and geological terms to assist in developing geotechnical recommendations for the project. 3.1.1 Test Borings The subsurface conditions were explored by drilling five (5) soil test borings within the proposed construction areas. A truck-mounted drill rig was utilized to drill the soil test borings. Borings were generally advanced to depths of 15 feet (the depth of proposed termination). Boring locations were identified in the field by ECS personnel using GPS techniques prior to mobilization of drilling equipment. The approximate as-drilled boring locations are shown on the Location Diagram in Appendix A. Standard penetration tests (SPT) were conducted in the borings at regular intervals in general accordance with ASTM D 1586. Small representative samples were obtained during these tests and were used to classify the soils encountered. The standard penetration resistances obtained provide a general indication of soil shear strength and compressibility. 3.1.2 Electric Resistivity (ER) Survey An ER survey was performed at the site. An ER survey is a non-invasive exploration method that can aid in the characterization of subsurface soil and rock conditions. During the subject ER survey, pins were driven into the ground, electrical current was applied to the ground at two locations, and a resulting voltage was recorded at two other locations. This allowed calculation of the apparent resistivity at a point centered between the four pins and at a depth related to the spacing of the pins. By moving the pins laterally, and by changing the spacing between the pins, a profile showing the apparent resistivity values at various depths along a line was produced. To aid in data collection, an array of multiple pins was laid out and connected to a single cable. This cable was then connected to an electrical resistivity meter which automatically selects various pin combinations to measure the apparent resistivity values across the line. Once the apparent resistivity data were recorded, the data were modeled to estimate the electrical resistivity profile. This modeled resistivity profile was then correlated to soils, voids, fracture zones, rock surfaces, and other geologic features. ECS conducted the ER survey utilizing a Syscal R1 24 probe automatic switching resistivity meter. Probe spacing was determined in the field and was designed to provide a maximum exploration depth of approximately 50 to 70 feet. A total of six (6) ER survey lines were performed as shown on the Exploration Location Diagram in Appendix A.


3.1.3 Laboratory Testing Program A geotechnical engineer classified each SPT soil sample on the basis of texture and plasticity in general accordance with the Unified Soil Classification System (USCS, ASTM D 2487). The group symbols for each soil type are indicated in parentheses following the soil descriptions on each boring log. A brief explanation of the USCS is included in the Appendix B. The engineer grouped the various soil types into the major zones noted on the boring logs. The stratification lines designating the interfaces between materials on the exploration records should be considered approximate; in situ, the transitions may be gradual. Representative soil samples were selected and tested in our laboratory to check field classifications and to determine pertinent index properties. The laboratory testing program included:

• Natural moisture content determinations (ASTM D 2216) • Atterberg Limits tests (ASTM D 4318)

The soil samples will be retained in our laboratory for a period of 60 days, after which, they will be discarded unless other instructions are received as to their disposition.


3.2 REGIONAL/SITE GEOLOGY

The USGS Geologic Map of the Ashland City Quadrangle (1967) indicates this particular site is underlain by the Warsaw Limestone Formation. This formation is typically a highly-jointed or fractured, bluish-gray, granular limestone with interbedded shale, capped with a layer of calcareous sandstone. This formation is subject to a high degree of solution weathering, and weathers to produce a layer of native soil (residuum) which is typically yellowish-brown clayey soil with an abundance of porous chert nodules. The chert nodules can disintegrate to give the soil a sandy texture. Normally, the soil/rock interface is irregular with soils extending into the rock mass and more resistant rock pinnacles protruding into the overburden soil.

Figure 3.2.1 - USGS Geologic Map of the Ashland City Quadrangle

(approximate site location highlighted)

3.3 SUBSURFACE CHARACTERIZATION

The site subsurface conditions were evaluated with 5 SPT borings at the approximate locations shown on the Location Diagram presented in Appendix A. The quantity of borings, boring locations, and drilling depths were discussed with the project team prior to completing this subsurface exploration. An approximately 1- to 8-inch thick layer of gravel was present in Borings B-2, B-4, and B-5. No surficial materials were encountered in the remaining boring locaions. The surficial material depths provided in this report and on the individual Boring Logs are based on driller observations and should be considered approximate. Below the surficial material in the borings listed above, or starting at the surface in Borings B-1 and B-3, CLAY material was encountered to the depth of boring termination. Borings B-2, B-4, and


B-5 encountered lean CLAY (CL) fill to depths of approximately 3 to 4 feet. SPT N-values for this fill layer varied from 25 to greater than 50 blows per foot (bpf). Borings B-1 through B-5 encountered native lean clays (CL) and fat clays (CH) with trace amounts of silt and gravel to the depths of termination. SPT N-values for the lean clay materials ranged from 24 to 33 bpf. SPT N-values for the fat clay materials varied from 19 to greater than 50 bpf. The subsurface conditions presented in Table 3.3.1 and shown on the Boring Logs should be considered approximate, based on interpretation of the exploration data using normally accepted geotechnical engineering judgments. It should be noted that transitions between different soil strata are typically less distinct than that shown on the exploration records. Subsurface conditions between the actual boring locations will vary. In addition, surficial material depths may also vary significantly across the site from those we encountered.

Table 3.3.1 - Summary of Subsurface Conditions

Boring No. Surface Material

Undocumented Fill Native Material Boring Termination

Depth Depth N-Values (bpf) Depth N-Values (bpf)

B-1 N/A - - 0 – 15 ft 25 – 33 15 ft

B-2 Gravel – 1 In. 1/12 – 3 ft 46 3 – 15 ft 20 – 28 15 ft

B-3 N/A - - 0 – 11 1/2 ft 26 – 32 11 1/2 ft*

B-4 Gravel – 8 In. 2/3 – 3 ft 25 3 – 15 ft 19 – 33 15 ft

B-5 Gravel – 3 In. 1/4 – 4 ft - 4 – 12 ft 26 12 ft* *AUGER REFUSAL


3.4 LABORATORY TEST RESULTS

Laboratory index test results indicate the in-situ moisture contents of the tested samples ranged from approximately 18 to 27 percent. An Atterberg Limits test was performed on a select soil sample from Boring B-1 indicated a low plasticity, lean CLAY (CL) with a Liquid Limit of 35 and a Plasticity Index of 9. An Atterberg Limits test was performed on a select soil sample from Boring B-3 indicated high plasticity, fat CLAY (CH) with a Liquid Limit of 58 and a Plasticity Index of 20. These results are summarized in Table 3.4.1 and have also been included on the boring logs and Laboratory Testing Summary in the Appendix.

Table 3.4.1 – Summary of Laboratory Test Results

Material Type Moisture Content Liquid Limit Plasticity Index

Lean CLAY (CL) 18 – 21% 35 9

Fat CLAY (CH) 24 – 27% 58 20

3.5 GROUNDWATER OBSERVATIONS

During drilling operations, groundwater was not encountered at the boring locations. However, it should be noted that it is possible for perched water to exist within the depths explored, particularly at the soil/rock interface during other times of the year depending upon climatic and rainfall conditions. Additionally, discontinuous zones of perched water may exist within the overburden materials.

Variations in the location of the long-term water table may occur as a result of change in precipitation, evaporation, surface water runoff, and other factors not immediately apparent at the time of this exploration.

3.6 ELECTRICAL RESITIVITY (ER) SURVEY

In order to get a better understanding of the depth to bedrock at the site, multiple ER survey lines were conducted across the site. Data collected during this study were analyzed utilizing Resix 2DI, an electrical resistivity two-dimensional modeling program. The specific modeling method used was a smooth modeling inversion method, which uses a rapid least squares inversion of apparent resistivity values to develop a smooth model of the subsurface characteristics. The results of this study provide subsurface information to an approximate depth of 50 to 70 feet. Modeled resistivity values were compared within and between profiles to develop an indication of the subsurface conditions. The ER profiles generated are included herein for reference. Possible subsurface features and patterns indicated by apparent resistivity values are shown on the profiles, if applicable.


The following is a discussion of the profiles with images provided. Larger images of the profiles are provided in Appendix B of this report.

Line 1

• Performed in an approximate North-South direction. • Total survey length of 345 feet. • Boring B-2 at approximately 165 feet from the start of line. Boring terminated at 15 feet. • Boring B-5 at approximately 235 feet from the start of line. Boring terminated at 15 feet. • Possible interference from utility line observed from approximately 120 to 135 feet from

the start of the line.

Line 2

• Performed in an approximate North-South direction. • Total survey length of 345 feet. • High resistivity zone, possible high chert/gravel content area noted across the majority of

the survey at depths generally shallower than 20 feet below the existing ground surface.


Line 3

• Performed in an approximate North-South direction. • Total survey length of 345 feet. • A possible soil filled slot/solution zone encountered at approximately 160 to 220 feet

from the start of the line.

Line 4

• Performed in an approximate West-East direction. • Total survey length of 345 feet. • Boring B-4 at approximately 185 feet from the start of line. Boring terminated at 15 feet. • High resistivity zone, possible high chert/gravel content area noted across the majority of

the survey


Line 5

• Performed in an approximate West-East direction. • Total survey length of 345 feet. • Boring B-5 at approximately 120 feet from the start of line. Boring terminated at 12 feet. • High resistivity zone, possible high chert/gravel content area noted across the majority of

the survey

Line 6

• Performed in an approximate Northwest-Southeast direction. • Total survey length of 345 feet. • Possible wet soil slots/solution zones encountered at 105 to 140 feet from the start of the

line.


4.0 PRELIMINARY DESIGN RECOMMENDATIONS

4.1 GENERAL

The primary purpose of this geotechnical exploration was to help identify and evaluate the general subsurface conditions relative to the proposed construction. Our preliminary recommendations have been developed on the basis of the previously described project information and subsurface conditions identified during this study. 4.1.1 Sinkhole Potential: This site is located within karst geology and is also prone to soil filled slots, which may be susceptible to sinkhole development. In addition, there is a noted closed depression on the provided topographic quadrangle map to the south and west of the proposed construction site. Furthermore, two possible solution zones were noted on ER Survey Lines 3 and 6. At the time of this report a preliminary site layout has not been completed. ECS should be contacted once a site plan has been generated to determine if these possible solutions features may have an impact on any of the proposed structural areas and the appropriate remediation method(s), if any, needed for the identified features. 4.1.2 Undocumented Fill: Existing undocumented fill materials were encountered during our exploration in Borings B-1 through B-3; however, there may still be the potential for additional areas with undocumented fill materials to exist on site in areas and depths that we have not explored. Undocumented fill materials should be handled in accordance with the recommendations in this report. 4.1.3 Highly Plastic Clays: Highly plastic clay (CH) soils were encountered on-site during our exploration. It is our opinion that the CH soils encountered at the boring locations are not suitable for the direct support of the proposed construction. Where encountered, we recommend undercutting the on-site clay (CH) soils to an appropriate depth as outlined in Section 4.2.4. 4.1.4 Preliminary Report: It should be emphasized that this is a preliminary geotechnical report and a proposed building scope, loading information, proposed site grading, and proposed site layout were not available at the time of this report. Once this information is available, ECS should be provided with this information to have an opportunity to make additional recommendation and determine if additional explorations are needed. 4.1.5 Construction Monitoring: ECS should be on-site full-time during earthwork and foundation construction activities to document that our recommendations are followed and to provide recommendations for remedial activities, where necessary. If we are not retained for this critical geotechnical consulting and during earthwork construction and foundation construction, ECS cannot be responsible for long-term performance of the respective grade-supported construction.

4.2 SUBGRADE PREPARATION

The following sections describe our general recommendations for preparing the site subgrade prior to fill placement operations.


4.2.1 Sinkhole Considerations Based on review of the Geologic Hazards Map of Tennessee (1977), this site does fall near a high risk sinkhole potential zone. Additionally, based on the results of the ER Survey, possible wet soil slots or solution-weathered zones potentially indicative of karst conditions were observed in Lines 3 and 6. Karst terrain is characterized by caves, caverns, voids, soil domes, soil raveling, interrupted drainage, disappearing streams, and topographical features such as sinkholes and closed depressions. These features are the result of the dissolution of soluble bedrock such as limestone, dolomite, and rock-like evaporates by groundwater and/or the infiltration of surface water.

Figure 4.2.1.1 - Geologic Hazards Map of Tennessee 1977 (approximate site location starred in

red, karst areas in purple)

The high frequency of sinkholes in the Ashland City area, and similar "karst" regions, is the result of variable solubility of the massive limestone bedrock in water. Water sources are normally twofold:

1) That which infiltrates into the subsurface unit as a result of normal precipitation, 2) Periodic fluctuation of the moving groundwater along joints and bedding planes in the

rock.


This "solution weathering" can result in the formation of frequently large cavities along bedding planes and joints in the rock. It is important to note that the rate of development of individual cavities in the rock and resulting sinkholes as described below, is a function of many factors, but likely takes thousands of years to develop fully. Eventually, open slots develop within the subsurface unit, at joint intersections or other weak locations in the unit. The stiff overburden soils bridge over the voids in the shape of an arch. Rainwater infiltrating the ground surface and flowing downward through the soil and fluctuation of the water table cause progressive spalling at the arched face. The void then expands upward toward the ground surface. When the void becomes large and extends close to the ground surface or when stress changes occur, the soil's shear strength is exceeded. The soil above the arch collapses, creating a surface depression or sinkhole. Any open conduit through the soil or rock through which water can flow freely to the cavities in the bedrock is referred to as the "throat”. With continued flow of surface water into the sinkhole, the depression enlarges. Secondary collapse of perimeter soil banks into the sinkhole and raveling of surface soils into the drainage feature also enlarge the depression. In the natural uncontrolled state, the "throat” of the sinkhole may become plugged, halting drainage and resulting in deposition of organic materials, unconsolidated soil, or water ponding in the depression. These natural conditions of low activity in untreated sinkholes are also a hazard, since at any time the throat may re-open or new throats may develop resulting in increased sinkhole activity or size. 4.2.2 Stripping and Grubbing The subgrade preparation should consist of stripping the vegetation, rootmat, topsoil, and other soft or unsuitable materials from the 10-foot expanded building and 5-foot expanded pavement limits and to 5 feet beyond the toe of structural fills. The boring data indicated that topsoil depths ranged from about 3 to 10 inches across the site. ECS should observe and document that topsoil and unsuitable surficial materials have been removed prior to the placement of structural fill or construction of structures. 4.2.3 Existing Man-Placed Fill Fill Content: Borings B-2, B-4, and B-5 encountered undocumented fill to depths of 4 feet below the ground surface. Fill Stability: N-values recorded in the fill materials were stiff and encountered at relatively shallow depths. Based on this information, it is possible to leave the undocumented fill in-place remove the unstable areas indicated by proofrolling with a loaded tandem-axle dump truck, provided the subgrade is free of organic material. 4.2.4 Proofrolling After removing unsuitable surface materials, excavation to the proposed grade, and prior to the placement of any structural fill or other construction materials, the exposed subgrade should be


examined by the Geotechnical Engineer or authorized representative. The exposed subgrade should be proofrolled with approved construction equipment having a minimum axle load of 10 tons (e.g. fully loaded tandem-axle dump truck). The areas subject to proofrolling should be traversed by the equipment in two perpendicular (orthogonal) directions with overlapping passes of the vehicle under the observation of the Geotechnical Engineer or authorized representative. This procedure is intended to assist in identifying any localized yielding materials. In the event that unstable or “pumping” subgrade is identified by the proofrolling, those areas should be repaired prior to the placement of any subsequent structural fill or other construction materials. Methods of repair of unstable subgrade may include undercutting or moisture conditioning or stone, geogrid, or chemical stabilization. The Geotechnical Engineer should be consulted to recommend the appropriate procedure with regard to the existing conditions causing the instability. Test pits may be excavated to explore the shallow subsurface materials in the area of the instability to help in assessing the cause of the observed unstable materials and to assist in the evaluation of the appropriate remedial action to stabilize the subgrade. 4.2.4 High Plasticity Soils Subgrade: High plasticity soils are those soil materials classified as fat clay (CH). High plasticity soils were encountered in many of the borings at variable depths. Where high plasticity soils are encountered at design subgrade elevations in slab and pavement areas, the subgrade should be undercut 1 foot and grades restored with approved structural fill. Where high plasticity soils are encountered at foundation bearing elevations, the foundation excavation should be lowered an additional 1 foot below the design footing subgrade elevation and the design elevation restored by backfilling the excavation with graded aggregate base and compacted with a vibratory plate compactor in maximum 12-inch lifts or with flowable fill having a minimum 28-day compressive strength of 1,000 psi. Lean Clay (CL) materials may also be used. Structural fills: High plasticity soils do not satisfy the specification criteria for satisfactory materials. Given the significant presence of high plasticity soils on this site, and to reduce the amount of import material to the site, the Owner can consider allowing soils with a maximum Liquid Limit of 60 and maximum Plasticity Index of 35 to be used as structural fill at depths greater than 4 feet below pavement subgrades outside the expanded building limits and within non-structural areas.

4.3 EARTHWORK OPERATIONS

4.3.1 Structural fill Materials Product Submittals: Prior to placement of structural fill, representative bulk samples (approximately 50 pounds) of on-site and off-site borrow should be submitted to ECS for laboratory testing, which will include Atterberg limits, natural moisture content, grain-size distribution, and moisture-density relationships for compaction. Import materials should be tested prior to being hauled to the site to determine if they meet project specifications. Satisfactory Structural fill Materials: Materials satisfactory for use as structural fill should consist of inorganic soils classified as CL, ML, SM, SC, SW, SP, GW, GP, GM and GC, or a combination of these group symbols, per ASTM D 2487. The materials should be free of organic matter, debris,


and should contain no particle sizes greater than 4 inches in the largest dimension. Open graded materials, such as Gravels (GW and GP), which contain void space in their mass should not be used in structural fills unless properly encapsulated with filter fabric. Suitable structural fill material should have the index properties shown in Table 4.3.1.1.

Table 4.3.1.1 Structural fill Index Properties Location with Respect to Final Grade LL PI

Building Areas 45 max 25 max

Pavement Areas 45 max 25 max

Building Areas, below upper 4 feet 60 max 35 max

Pavement Areas, below upper 2 feet 60 max 35 max

Unsatisfactory Materials: Unsatisfactory fill materials include materials which to not satisfy the requirements for suitable materials, as well as topsoil and organic materials (OH, OL), elastic Silt (MH), and high plasticity Clay (CH). Use of Shotrock: Properly-graded shotrock from blasted or excavated bedrock is generally suitable for use as engineered “shotrock” fill or backfill at this site. The first layer of fill should be placed in a relatively uniform horizontal lift and be adequately keyed into the stripped and scarified subgrade soils. Shotrock fill materials for this project shall meet the following requirements:

• Well-graded rock, with sufficient “fines” (material passing the No. 4 sieve)

• No more than 20% fines by weight in the total composite fill material

• Placed in a manner that promotes rock-to-rock contact between larger rock and fines to fill voids between larger-diameter shotrock

• Maximum particle size of 18 inches

To ease the installation of foundations and utilities, we recommend that the maximum particle size of shotrock fill used within the upper two to three feet of the subgrade be limited to 8 inches in diameter. Shotrock fill should be placed in maximum 18-inch lifts of loose material and compacted with overlapping perpendicular passes by a minimum sized D-8 bulldozer or equivalent, but preferably a CAT 815 compactor. Each lift of compacted shotrock fill should be approved through proofroll observations or testing by a representative of the geotechnical engineer prior to placement of subsequent lifts. Each lift of fill shall be unyielding under the proofrolling load prior to the placement of the next lift of fill. The edges of compacted fill should extend 10 feet beyond the edges of structural areas prior to sloping, where applicable.


4.3.2 Compaction Structural fill Compaction: Structural fill within the expanded building, pavement, and embankment limits should be placed in maximum 8-inch loose lifts, moisture conditioned as necessary to within -3 and +3 % of the soil’s optimum moisture content, and be compacted with suitable equipment to a dry density of at least 95% of the Standard Proctor maximum dry density (ASTM D698). ECS should be present onsite during earthwork operations to document that proper fill compaction has been achieved. Fill Compaction Control: The expanded limits of the proposed construction areas should be well defined, including the limits of the fill zones for buildings, pavements, and slopes, etc., at the time of fill placement. Grade controls should be maintained throughout the filling operations. Filling operations should be observed on a full-time basis by ECS to document that the minimum compaction requirements are being achieved. Field density testing of fills should be performed at the frequencies shown in Table 4.3.1.2, but not less than 2 tests per lift.

Table 4.3.1.2 Frequency of Compaction Tests in Fill Areas Location Frequency of Tests

Expanded Building Limits 1 test per 2,500 sq. ft. per lift

Pavement Areas 1 test per 10,000 sq. ft. per lift

Utility Trenches 1 test per 200 linear ft. per lift

Compaction Equipment: Compaction equipment suitable to the soil type being compacted should be used to compact the subgrades and fill materials. Sheepsfoot compaction equipment should be suitable for the fine-grained soils (clays and silts). A vibratory steel drum roller should be used for compaction of coarse-grained soils (sands) as well as for sealing compacted surfaces. Fill Placement Considerations: Fill materials should not be placed on frozen soils, on frost-heaved soils, and/or on excessively wet soils. Borrow fill materials should not contain frozen materials at the time of placement, and all frozen or frost-heaved soils should be removed prior to placement of Structural fill or other fill soils and aggregates. Excessively wet soils or aggregates should be scarified, aerated, and moisture conditioned.

At the end of each work day, all fill areas should be graded to facilitate drainage of precipitation and the surface should be sealed by use of a smooth-drum roller to limit infiltration of surface water. During placement and compaction of new fill at the beginning of each workday, the Contractor may need to scarify existing subgrades to a depth on the order of 4 inches so that a weak plane will not be formed between the new fill and the existing subgrade soils. Drying and compaction of wet soils is typically difficult during the cold, winter months. Accordingly, earthwork should be performed during the warmer, drier times of the year, if practical. Proper drainage should be maintained during the earthwork phases of construction to prevent ponding of water which has a tendency to degrade subgrade soils.


Where fill materials will be placed to widen existing embankment fills, or placed up against sloping ground, the soil subgrade should be scarified and the new fill benched or keyed into the existing material. Fill material should be placed in horizontal lifts. In confined areas such as utility trenches, portable compaction equipment and thin lifts of 3 inches to 4 inches may be required to achieve specified degrees of compaction. We recommend that the grading contractor have equipment on site during earthwork for both drying and wetting fill soils. We do not anticipate significant problems in controlling moisture within the fill during dry weather, but moisture control may be difficult during winter months or extended periods of rain. The control of moisture content of higher plasticity soils is difficult when these soils become wet. Further, such soils are easily degraded by construction traffic when the moisture content is elevated.

4.4 UTILITY INSTALLATIONS

Utility Subgrades: The soils encountered in our exploration are expected to be generally suitable for support of utility pipes. The pipe subgrade should be observed and probed for stability by ECS to evaluate the suitability of the materials encountered. Loose or unsuitable materials encountered at the utility pipe subgrade elevation should be removed and replaced with suitable compacted structural fill or pipe bedding material. Utility Backfilling: The granular bedding material should be at least 4 inches thick, but not less than that specified by the project drawings and specifications. Fill placed for support of the utilities, as well as backfill over the utilities, should satisfy the requirements for Structural fill given in this report. Compacted backfill should be free of topsoil, roots, ice, or any other material designated by ECS as unsuitable. The backfill should be moisture conditioned, placed, and compacted in accordance with the recommendations of this report. Excavation Safety: All excavations and slopes should be made and maintained in accordance with OSHA excavation safety standards. The contractor is solely responsible for designing and constructing stable, temporary excavations and slopes and should shore, slope, or bench the sides of the excavations and slopes as required to maintain stability of both the excavation sides and bottom. The contractor’s responsible person, as defined in 29 CFR Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety procedures. In no case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations. ECS is providing this information solely as a service to our client. ECS is not assuming responsibility for construction site safety or the contractor’s activities; such responsibility is not being implied and should not be inferred.

4.5 BUILDING DESIGN

The following sections provide preliminary recommendations for foundation design, soil supported slabs, pavements, and seismic design parameters.


4.5.1 Foundations Provided subgrades and structural fills are prepared as discussed herein, the proposed structure can be supported by conventional shallow foundations consisting of individual column footings and continuous wall footings. The design of the foundation should utilize the following parameters:

Table 4.5.1.1 Foundation Design Design Parameter Column Footing Wall Footing

Net Allowable Bearing Pressure1 2,500 psf 2,500 psf

Acceptable Bearing Soil Material2

Engineered Fill or Natural Materials

(CL)

Engineered Fill or Natural Materials

(CL)

Minimum Width 18 inches 18 inches

Minimum Footing Embedment Depth

(below slab or finished grade)

18 inches 18 inches

Estimated Total Settlement Less than 1 inch Less than 1 inch

Estimated Differential Settlement

Less than 0.5 inches between columns

Less than 0.5 inches over 50 feet

1. Net allowable bearing pressure is the applied pressure in excess of the surrounding overburden soils

above the base of the foundation.

2. Assumes that if highly plastic clays are encountered at the foundation bearing elevation they are removed as described in section 4.2.4 of this report.

Horizontal loads acting on shallow foundations are resisted by friction along the foundation base and by passive pressure against the footing face that is perpendicular to the line of applied force. The coefficient of friction between the base of the footing and the subgrade soil is estimated to be 0.30. A passive soil resistance equal to a uniform pressure of 295 psf may be used for undisturbed residual soils or properly-compacted structural fill against the face of the footing. We recommend that a minimum factor of safety of 1.5 should be used for estimating lateral capacities. Protection of Foundation Excavations: Exposure to the environment may weaken the soils at the footing bearing level if the foundation excavations remain open for too long a time. Therefore, foundation concrete should be placed the same day that excavations are made. If the bearing soils are softened by surface water intrusion or exposure, the softened soils must be removed from the foundation excavation bottom immediately prior to placement of concrete. If the excavation must remain open overnight, or if rainfall becomes imminent while the bearing soils


are exposed, a 1 to 3-inch thick “mud mat” of “lean” concrete should be placed on the bearing soils before the placement of reinforcing steel. Footing Subgrade Observations: Most of the soils at the foundation bearing elevation are anticipated to be suitable for support of the proposed structure. It will be important to have the Geotechnical Engineer of record observe the foundation subgrade prior to placing foundation concrete, to confirm the bearing soils are capable of supporting the design bearing pressures. If soft or unsuitable soils are observed at the footing bearing elevations, the unsuitable soils should be undercut and removed. Any undercut should be backfilled with lean concrete (f’c ≥ 1,000 psi at 28 days) or dense graded aggregate fill up to the original design bottom of footing elevation; the original footing shall be constructed on top of the hardened lean concrete or aggregate fill. 4.5.2 Floor Slabs The on-site native lean clay (CL) soils appear to be suitable for support of the lowest floor slabs. Where highly plastic clay (CH) material is encountered it should be undercut 1 foot below proposed subgrade elevation and low plasticity engineered fill should then be placed and compacted. The following graphic depicts our soil-supported slab recommendations:

Figure 4.5.2.1

1. Drainage Layer Thickness: 4 inches

2. Drainage Layer Material: GRAVEL (GP, GW), SAND (SP, SW)

3. Subgrade compacted to 95% maximum dry density per ASTM D698

Subgrade Modulus: Provided the placement of structural fill and granular drainage layer per the recommendations discussed herein, the slab may be designed assuming a modulus of subgrade reaction, k1 of 110 pci (lbs/cu. inch). Slab Isolation: Ground-supported slabs should be isolated from the foundations and foundation-supported elements of the structure so that differential movement between the foundations and slab will not induce excessive shear and bending stresses in the floor slab. For maximum effectiveness, temperature and shrinkage reinforcements in slabs-on-grade should be considered and incorporated accordingly in the slab design. If welded-wire mesh reinforcement is utilized, the mesh reinforcement should be placed 2 inches below the slab surface or within the upper one-third of the slab thickness, whichever is closer to the surface. Adequate construction joints, contraction joints and isolation joints should also be provided in the slab to reduce the impacts of cracking and shrinkage, in general accordance with ACI standards and guidelines (360R-10).

Concrete Slab Vapor Barrier

Granular Capillary Break/Drainage Layer

Compacted Subgrade


Project specific design recommendations made by the Structural Engineer of Record should control over the above general comments. 4.5.3 Seismic Design Considerations

Seismic Site Classification: The International Building Code (IBC) 2012 requires site classification for seismic design based on the upper 100 feet of a soil profile. Three methods are utilized in classifying sites, namely the shear wave velocity (vs) method; the unconfined compressive strength (su) method; and the Standard Penetration Resistance (N-value) method. The third method (N-Value) was used in classifying this site. The seismic site class definitions for the weighted average of shear wave velocity or SPT N-value in the upper 100 feet of the soil profile are shown in the following table:

Table 4.5.3.1: Seismic Site Classification Site

Class Soil Profile Name Shear Wave Velocity, Vs, (ft./s)

N value (bpf)

A Hard Rock Vs > 5,000 fps N/A

B Rock 2,500 < Vs ≤ 5,000 fps N/A

C Very dense soil and soft rock 1,200 < Vs ≤ 2,500 fps >50

D Stiff Soil Profile 600 ≤ Vs ≤ 1,200 fps 15 to 60

E Soft Soil Profile Vs < 600 fps <15 Based on the SPT boring data, ECS recommends a Seismic Site Class “D”. Ground Motion Parameters: In addition to the seismic site classification noted above, ECS has determined the design spectral response acceleration parameters following the IBC 2012 methodology. The Mapped Reponses were estimated from the free Java Ground Motion Parameter Calculator available from the USGS website (http://earthquake.usgs.gov/designmaps/us/application.php). The design responses for the short (0.2 sec, SDS) and 1-second period (SD1) are noted in bold at the far right end of the following table and were considered for the project site located at approximate Latitude 36.310021 and an approximate Longitude of -87.034892.


Table 4.5.3.2: Ground Motion Parameters “Class D” (IBC 2012 Method)

Period (sec)

Mapped Spectral Response

Accelerations (g)

Values of Site Coefficient

for Site Class

Maximum Spectral Response Acceleration

Adjusted for Site Class (g)

Design Spectral Response

Acceleration (g)

Reference Figures 1613.3.1 (1) & (2)

Tables 1613.3.3 (1) & (2)

Eqs. 16-37 & 16-38

Eqs. 16-39 & 16-40

0.2 SS 0.35 Fa 1.52 SMS=FaSs 0.532 SDS=2/3

SMS 0.355

1.0 S1 0.16 Fv 2.159 SM1=FvS1 0.346 SD1=2/3

SM1 0.231

The Site Class definition should not be confused with the Seismic Design Category designation, which the Structural Engineer typically assesses. If a higher site classification is beneficial to the project, ECS would be pleased to discuss additional testing capabilities in this regard.

4.6 SITE DESIGN CONSIDERATIONS

4.6.1 Slope Evaluations and Stability Analyses In general, fill slopes should be no steeper than 3 horizontal to 1 vertical (3H:1V) and over-built and cut back to their planned inclination. The potential for surface erosion of earth slopes should be reduced by establishing deep rooted vegetation on the slope face as soon as the final slope geometry is achieved. Surface water controls should be planned near the crest of all slopes to help prevent surface water runoff from up gradient areas flowing over the face of the slope. In building and pavement areas, minimum top of slope setbacks of 10 feet and 5 feet are recommended, respectively. During foundation excavation and utility installation, the existing on-site soils should be observed by a geotechnical engineer and should be benched or sloped back at appropriate gradients, in accordance with OSHA 29 CFR 1926. It should be understood that, during wet weather and cold weather conditions, seepage and freeze/thaw conditions may decrease the stability of cuts. During construction, temporary slopes should be regularly evaluated for signs of movement, seepage, or an unsafe condition. Soil slopes should be covered for protection from rain and surface runoff conditions. Stormwater runoff shall not be permitted to overtop the crests of slopes, and therefore must be diverted away from the slopes. 4.6.2 Pavement Sections Our scope of services did not include sampling and California Bearing Ratio (CBR) testing of existing subgrade or potential sources of imported fill for the specific purpose of a detailed pavement analysis. Instead, we have assumed pavement-related design parameters that are considered to be typical for the local on-site soils and assumed traffic conditions. The recommended pavement thicknesses presented in this report section are considered typical and minimum for the assumed parameters in the general site area. We understand that budgetary considerations sometimes warrant thinner pavement sections than those presented.


However, the client, the owner, and the project designers should be aware that thinner pavement sections may result in increased maintenance costs and lower than anticipated pavement life. We have estimated the final pavement subgrade soils will be sufficient to achieve a minimum composite CBR of 3, provided the subgrade preparation recommendations as previously stated are followed. We have also assumed traffic loading for automobile parking and roads/drive lanes to be approximately 50,000, 200,000, and 500,000 ESAL’s, respectively, for a 20-year design life. If the actual loading is anticipated to be more or less, we should be allowed the opportunity to revise our recommendations. Based on these assumptions, we recommend typical pavement sections consisting of the following:

Table 4.6.2.1 Recommended Minimum Flexible Asphalt Pavement Thicknesses

Pavement Materials Light Duty (50,000 ESALs)

Medium Duty (200,000 ESALs)

Heavy Duty (500,000 ESALs)

Asphaltic Surface Course 1½ inch 2½ inches 2½ inches

Asphaltic Binder Course 2 inches 2½ inches 3 inches

Crushed Stone Base 8 inches 8 inches 10 inches We recommend that the subbase stone and bituminous asphalt pavements be compacted in accordance with local DOT requirements. Rigid concrete pavement may be used instead of flexible pavement. The typical rigid pavement sections are listed below. Rigid pavement is recommended to be used where trash dumpsters or heavy trucks are to be parked on the pavement and a considerable load is transferred to the pavements. We also recommend rigid pavement in drive-through service lanes. Use of rigid pavement should provide better distribution of surface loads to the subgrade without allowing intolerable surficial deformation or rutting.

Table 4.6.2.2 Recommended Minimum Rigid Pavement Thicknesses

Pavement Materials Light Duty (50,000 ESALs) Medium Duty (200,000 ESALs)

Heavy Duty (500,000 ESALs)

Reinforcement As required by designer As required by designer As required by designer

Dowels at Joints 5/8” diameter x 18”

long at 12” c-c

7/8” diameter x 18” long

at 12” c-c

7/8” diameter x 18” long at 12” c-c

Portland Cement Concrete

f’c=4000 psi 5 inches 6¼ inches 7¼ inches

Crushed Stone Base 6 inches 6 inches 6 inches


The above sections represent minimum thickness representative of typical local construction practices, and periodic maintenance should be anticipated. Pavement may be placed after the subgrade has been properly compacted, fine graded, and proofrolled as recommended earlier in this report. Actual pavement section thickness and joint spacing, if applicable, should be determined by the design civil engineer or geotechnical engineer based on traffic loads, volume, and the owner’s design life requirements. Water should not be allowed to pond behind curbs and saturate the pavement base stone. In down-grade areas, base stone should extend through the slope face to allow any water entering the base stone a path to exit. An important consideration with the design and construction of pavements is surface and subsurface drainage. Where standing water develops, either on the pavement surface or within the base course layer, softening of the subgrade and other problems related to the deterioration of the pavement can be expected. Furthermore, good drainage should reduce the possibility of the subgrade materials becoming saturated over a long period of time. We would be pleased to be of further assistance to you in the design of the project pavements by providing additional recommendations during construction of the project. It should be noted that representative samples should be collected from the upper 2 feet of the final roadway soil subgrade to assess the suitability of the in-situ CBR values, prior to implementation of the pavement sections provided herein. Often during construction and preparation of the roadway subgrade, the soil materials may be improved and can sometimes yield reduced pavement sections based on the actual CBR values and traffic loads. 4.6.3 Pavement Maintenance Regular maintenance and occasional repairs should be implemented to keep pavements in a serviceable condition. In addition, to help minimize water infiltration to the pavement section and within the base course layer resulting in softening of the subgrade and deterioration of the pavement, we recommend the timely sealing of joints and cracks using proper sealants. We recommend exterior pavements be reviewed for distress/cracks twice a year, once in the spring and once in the fall. Sound maintenance programs should help maintain and enhance the performance of pavements and attain the design service life. A preventative maintenance program should be implemented early in the pavement life to be effective. The “standard in the industry” supported by research indicates that preventative maintenance should begin within 2 to 5 years of the pavement construction. Failure to perform preventative maintenance will reduce the service life of the pavement and increase the costs for both corrective maintenance and full pavement rehabilitation.

4.7 GENERAL CONSTRUCTION CONSIDERATIONS

Moisture Conditioning: During the cooler and wetter periods of the year, delays and additional costs should be anticipated. At these times, reduction of soil moisture may need to be accomplished by a combination of mechanical manipulation and the use of chemical additives, such as lime or cement, in order to lower moisture contents to levels appropriate for compaction.


Alternatively, during the drier times of the year, such as the summer months, moisture may need to be added to the soil to provide adequate moisture for successful compaction according to the project requirements. Subgrade Protection: Measures should also be taken to limit site disturbance, especially from rubber-tired heavy construction equipment, and to control and remove surface water from development areas, including structural and pavement areas. It would be advisable to designate a haul road and construction staging area to limit the areas of disturbance and to prevent construction traffic from excessively degrading sensitive subgrade soils and existing pavement areas. Haul roads and construction staging areas could be covered with excess depths of aggregate to protect those subgrades. The aggregate can later be removed and used in pavement areas. Surface Drainage: Surface drainage conditions should be properly maintained. Surface water should be directed away from the construction area, and the work area should be sloped away from the construction area at a gradient of 1 percent or greater to reduce the potential of ponding water and the subsequent saturation of the surface soils. At the end of each work day, the subgrade soils should be sealed by rolling the surface with a smooth drum roller to minimize infiltration of surface water. Excavation Safety: Cuts or excavations associated with utility excavations may require forming or bracing, slope flattening, or other physical measures to control sloughing and/or prevent slope failures. Contractors should be familiar with applicable OSHA codes to ensure that adequate protection of the excavations and trench walls is provided. Erosion Control: The surface soils may be erodible. Therefore, the Contractor should provide and maintain good site drainage during earthwork operations to maintain the integrity of the surface soils. All erosion and sedimentation controls should be in accordance with sound engineering practices and local requirements.


5.0 CLOSING

ECS has prepared this preliminary report of findings, evaluations, and recommendations to guide geotechnical-related design and construction aspects of the project. The description of the proposed project is based on information provided to ECS by Rufus Johnson Associates and Cheatham County If any of this information is inaccurate, either due to our interpretation of the documents provided or site or design changes that may occur later, ECS should be contacted immediately in order that we can review the report in light of the changes and provide additional or alternate recommendations as may be required to reflect the proposed construction. We recommend that ECS be allowed to review the project’s plans and specifications pertaining to our work so that we may ascertain consistency of those plans/specifications with the intent of the geotechnical report. Field observations, monitoring, and quality assurance testing during earthwork and foundation installation are an extension of and integral to the geotechnical design recommendation. We recommend that the owner retain these quality assurance services and that ECS be allowed to continue our involvement throughout these critical phases of construction to provide general consultation as issues arise. ECS is not responsible for the conclusions, opinions, or recommendations of others based on the data in this report.


APPENDIX A – Drawings & Reports

Site Vicinity Diagram Exploration Location Diagram

George Boyd Road Preliminary

Geotechnical Assessment

1027 George Boyd Road

Ashland City, TN

ECS Project No. 26:3774

Figure 1: Site Vicinity Map

NOT TO SCALE

Figure 2: Location Diagram

Approximate Boring Locations

Approximate ER Line Locations

George Boyd Road Preliminary

Geotechnical Assessment

1027 George Boyd Road

Ashland City, TN

ECS Project No. 26:3774

Line 1

Line 2

Line 3Line 4

Line 5

Line 6


APPENDIX B – Field Operations

Reference Notes for Boring Logs Boring Logs B-1 through B-5 ER Survey Line 1 through Line 6

Reference Notes for Boring Logs (03-22-2017) © 2017 ECS Corporate Services, LLC. All Rights Reserved

COHESIVE SILTS & CLAYS

UNCONFINED

COMPRESSIVE

STRENGTH, QP4

SPT5

(BPF)

CONSISTENCY7

(COHESIVE)

<0.25 <3 Very Soft

0.25 - <0.50 3 - 4 Soft

0.50 - <1.00 5 - 8 Firm

1.00 - <2.00 9 - 15 Stiff

2.00 - <4.00 16 - 30 Very Stiff

4.00 - 8.00 31 - 50 Hard

>8.00 >50 Very Hard

GRAVELS, SANDS & NON-COHESIVE SILTS

SPT5

DENSITY

<5 Very Loose

5 - 10 Loose

11 - 30 Medium Dense

31 - 50 Dense

>50 Very Dense

REFERENCE NOTES FOR BORING LOGS

1Classifications and symbols per ASTM D 2488-09 (Visual-Manual Procedure) unless noted otherwise.

2To be consistent with general practice, “POORLY GRADED” has been removed from GP, GP-GM, GP-GC, SP, SP-SM, SP-SC soil types on the boring logs.

3Non-ASTM designations are included in soil descriptions and symbols along with ASTM symbol [Ex: (SM-FILL)].

4Typically estimated via pocket penetrometer or Torvane shear test and expressed in tons per square foot (tsf).

5Standard Penetration Test (SPT) refers to the number of hammer blows (blow count) of a 140 lb. hammer falling 30 inches on a 2 inch OD split spoon sampler required to drive the sampler 12 inches (ASTM D 1586). “N-value” is another term for “blow count” and is expressed in blows per foot (bpf).

6The water levels are those levels actually measured in the borehole at the times indicated by the symbol. The measurements are relatively reliable when augering, without adding fluids, in granular soils. In clay and cohesive silts, the determination of water levels may require several days for the water level to stabilize. In such cases, additional methods of measurement are generally employed.

7Minor deviation from ASTM D 2488-09 Note 16.

8Percentages are estimated to the nearest 5% per ASTM D 2488-09.

RELATIVE

AMOUNT7

COARSE GRAINED

(%)8

FINE

GRAINED

(%)8

Trace <5 <5

Dual Symbol (ex: SW-SM)

10 10

With 15 - 20 15 - 25

Adjective (ex: “Silty”)

>25 >30

WATER LEVELS6

WL Water Level (WS)(WD)

(WS) While Sampling

(WD) While Drilling

SHW Seasonal High WT

ACR After Casing Removal

SWT Stabilized Water Table

DCI Dry Cave-In

WCI Wet Cave-In

DRILLING SAMPLING SYMBOLS & ABBREVIATIONS

SS Split Spoon Sampler PM Pressuremeter Test

ST Shelby Tube Sampler RD Rock Bit Drilling

WS Wash Sample RC Rock Core, NX, BX, AX

BS Bulk Sample of Cuttings REC Rock Sample Recovery %

PA Power Auger (no sample) RQD Rock Quality Designation %

HSA Hollow Stem Auger

PARTICLE SIZE IDENTIFICATION

DESIGNATION PARTICLE SIZES

Boulders 12 inches (300 mm) or larger

Cobbles 3 inches to 12 inches (75 mm to 300 mm)

Gravel: Coarse ¾ inch to 3 inches (19 mm to 75 mm)

Fine 4.75 mm to 19 mm (No. 4 sieve to ¾ inch)

Sand: Coarse 2.00 mm to 4.75 mm (No. 10 to No. 4 sieve)

Medium 0.425 mm to 2.00 mm (No. 40 to No. 10 sieve)

Fine 0.074 mm to 0.425 mm (No. 200 to No. 40 sieve)

Silt & Clay (“Fines”) <0.074 mm (smaller than a No. 200 sieve)

MATERIAL1,2

ASPHALT

CONCRETE

GRAVEL

TOPSOIL

VOID

BRICK

AGGREGATE BASE COURSE

FILL

3 MAN-PLACED SOILS

GW WELL-GRADED GRAVEL

gravel-sand mixtures, little or no fines

GP POORLY-GRADED GRAVEL gravel-sand mixtures, little or no fines

GM SILTY GRAVEL

gravel-sand-silt mixtures

GC CLAYEY GRAVEL

gravel-sand-clay mixtures

SW WELL-GRADED SAND

gravelly sand, little or no fines

SP POORLY-GRADED SAND

gravelly sand, little or no fines

SM SILTY SAND

sand-silt mixtures

SC CLAYEY SAND

sand-clay mixtures

ML SILT non-plastic to medium plasticity

MH ELASTIC SILT

high plasticity

CL LEAN CLAY low to medium plasticity

CH FAT CLAY

high plasticity

OL ORGANIC SILT or CLAY

non-plastic to low plasticity

OH ORGANIC SILT or CLAY

high plasticity

PT PEAT highly organic soils

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

S-5

SS

SS

SS

SS

SS

18

18

18

18

18

18

18

16

18

18

(CL) LEAN CLAY, trace sand, trace gravel, lightreddish brown, moist, very stiff

(CH) FAT CLAY, trace sand, trace gravel,reddish brown, moist, very stiff

END OF BORING @ 15'

71114

91214

121518

121318

151514

25

35

26

17.8

3.5

2618.1 4

3321.14

3120.04

2923.6

4

CLIENT

Rufus Johnson & Associates

Job #:

26:3774

BORING #

B-1

SHEET

PROJECT NAME

George Boyd Road Geotechnical Assessment

ARCHITECT-ENGINEER

SITE LOCATION

1027 George Boyd Road, Ashland City, Cheatham, TNNORTHING EASTING STATION

THE STRATIFICATION LINES REPRESENT THE APPROXIMATE BOUNDARY LINES BETWEEN SOIL TYPES. IN-SITU THE TRANSITION MAY BE GRADUAL.

WL WS WD BORING STARTED 04/02/19 CAVE IN DEPTH

WL(SHW) WL(ACR) BORING COMPLETED 04/02/19 HAMMER TYPE Auto

WL RIG Truck FOREMAN T. Hibdon DRILLING METHOD HSA/SPTDRILLING METHOD HSA/SPT

DE

PT

H (

FT

)

SA

MP

LE

NO

.

SA

MP

LE

TY

PE

SA

MP

LE

DIS

T.

(IN

)

RE

CO

VE

RY

(IN

)

SURFACE ELEVATION

DESCRIPTION OF MATERIAL

WA

TE

R L

EV

ELS

ELE

VA

TIO

N (

FT

)

BLO

WS

/6"

10 20 30 40 50+

20% 40% 60% 80% 100%

1 2 3 4 5+

ENGLISH UNITS

BOTTOM OF CASING LOSS OF CIRCULATION

CALIBRATED PENETROMETER TONS/FT2

PLASTICLIMIT %

WATERCONTENT %

LIQUIDLIMIT %

ROCK QUALITY DESIGNATION & RECOVERY

RQD% REC.%

STANDARD PENETRATIONBLOWS/FT

1 OF 1

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

S-5

SS

SS

SS

SS

SS

18

18

18

18

18

14

10

15

17

7

Gravel Thickness [1.00"]

(CL FILL) FILL, LEAN CLAY, trace sand, tracegravel, brown, moist



END OF BORING @ 15'

121729

9159

231216

91010

101012

461

24

3.5

284

204

22

3.5

CLIENT


Job #:

26:3774

BORING #

B-2

SHEET

PROJECT NAME


ARCHITECT-ENGINEER

SITE LOCATION






DE

PT

H (

FT

)

SA

MP

LE

NO

.

SA

MP

LE

TY

PE

SA

MP

LE

DIS

T.

(IN

)

RE

CO

VE

RY

(IN

)

SURFACE ELEVATION


WA

TE

R L

EV

ELS

ELE

VA

TIO

N (

FT

)

BLO

WS

/6"

10 20 30 40 50+

20% 40% 60% 80% 100%

1 2 3 4 5+

ENGLISH UNITS



PLASTICLIMIT %

WATERCONTENT %

LIQUIDLIMIT %


RQD% REC.%


1 OF 1

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

SS

SS

SS

SS

18

18

18

18

18

18

18

18


AUGER REFUSAL @ 11.5'

71219

71313

81215

81319

3127.04

26 5838

27.2 4

27 26.74

3224.5

4

CLIENT


Job #:

26:3774

BORING #

B-3

SHEET

PROJECT NAME


ARCHITECT-ENGINEER

SITE LOCATION






DE

PT

H (

FT

)

SA

MP

LE

NO

.

SA

MP

LE

TY

PE

SA

MP

LE

DIS

T.

(IN

)

RE

CO

VE

RY

(IN

)

SURFACE ELEVATION


WA

TE

R L

EV

ELS

ELE

VA

TIO

N (

FT

)

BLO

WS

/6"

10 20 30 40 50+

20% 40% 60% 80% 100%

1 2 3 4 5+

ENGLISH UNITS



PLASTICLIMIT %

WATERCONTENT %

LIQUIDLIMIT %


RQD% REC.%


1 OF 1

0

5

10

15

20

25

30

S-1

S-2

S-3

S-4

S-5

SS

SS

SS

SS

SS

18

18

18

18

18

18

18

18

18

15





END OF BORING @ 15'

61213

81617

8910

101115

6129

254

33

4

19 4

264

21

CLIENT


Job #:

26:3774

BORING #

B-4

SHEET

PROJECT NAME


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AUGER REFUSAL @ 12'

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Job #:

26:3774

BORING #

B-5

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Line 1 ER Survey Results (North is to the Left)


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Possible Interference From Utility Line

George Boyd Road Property

1027 George Boyd RoadAshland City, TennesseeECS Proposal No. 26-3774

B-2EOB @ 15’

High Resistivity Zone Possible High Chert

Content Area

B-5EOB @ 15’

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Low Resistivity Zone Possible Karst Area


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Line 5 ER Survey Results (West is to the Left)

Line 6 ER Survey Results (Northwest is to the Left)



B-5EOB @ 12’


Content Area

Low Resistivity Zone Possible Karst Area


APPENDIX C – Laboratory Testing

Laboratory Test Results Summary

B-1S-1 1.00 - 2.5 17.8 35 26 9S-2 3.50 - 5.0 18.1S-3 6.00 - 7.5 21.1S-4 8.50 - 10.0 20.0S-5 13.50 - 15.0 23.6

Laboratory Testing Summary

Notes: 1. ASTM D 2216, 2. AASHTO T27, 3. AASHTO T89 and AASHTO T90, 4. AASHTO T11, 5. See test reports for test method, 6. See test reports for test method

Definitions: MC: Moisture Content, Soil Type:AASHTO, LL: Liquid Limit, PL: Plastic Limit, PI: Plasticity Index, CBR: California Bearing Ratio, OC: Organic Content (ASTM D 2974)

Project No. 26:3774

Project Name: George Boyd Road Geotechnical Assessment

Client: Rufus Johnson & Associates

Printed On: Tuesday, April 09, 2019

BoringNumber

SampleNumber

Depth(feet)

MC1

(%)Soil

Type2 LL

Atterberg Limits3

PL PI

PercentPassingNo. 200Sieve4

MaximumDensity

(pcf)

Moisture - Density (Corr.)5

OptimumMoisture

(%)

CBRValue6 Other

Page 1 of 1

B-3S-1 1.00 - 2.5 27.0S-2 3.50 - 5.0 27.2 58 38 20S-3 6.00 - 7.5 26.7S-4 8.50 - 10.0 24.5

Laboratory Testing Summary

Notes: 1. ASTM D 2216, 2. AASHTO T27, 3. AASHTO T89 and AASHTO T90, 4. AASHTO T11, 5. See test reports for test method, 6. See test reports for test method

Definitions: MC: Moisture Content, Soil Type:AASHTO, LL: Liquid Limit, PL: Plastic Limit, PI: Plasticity Index, CBR: California Bearing Ratio, OC: Organic Content (ASTM D 2974)

Project No. 26:3774

Project Name: George Boyd Road Geotechnical Assessment

Client: Rufus Johnson & Associates

Printed On: Tuesday, April 09, 2019

BoringNumber

SampleNumber

Depth(feet)

MC1

(%)Soil

Type2 LL

Atterberg Limits3

PL PI

PercentPassingNo. 200Sieve4

MaximumDensity

(pcf)

Moisture - Density (Corr.)5

OptimumMoisture

(%)

CBRValue6 Other

Page 1 of 1


APPENDIX D – Supplemental Report Documents

Seismic Design Map Important Information

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Geotechnical-Engineering ReportImportant Information about This

Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.

While you cannot eliminate all such risks, you can manage them. The following information is provided to help.

The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, clients can benefit from a lowered exposure to the subsurface problems that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed below, contact your GBA-member geotechnical engineer. Active involvement in the Geoprofessional Business Association exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project.

Geotechnical-Engineering Services Are Performed for Specific Purposes, Persons, and ProjectsGeotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Those who rely on a geotechnical-engineering report prepared for a different client can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first conferring with the geotechnical engineer who prepared it. And no one – not even you – should apply this report for any purpose or project except the one originally contemplated.

Read this Report in FullCostly problems have occurred because those relying on a geotechnical-engineering report did not read it in its entirety. Do not rely on an executive summary. Do not read selected elements only. Read this report in full.

You Need to Inform Your Geotechnical Engineer about ChangeYour geotechnical engineer considered unique, project-specific factors when designing the study behind this report and developing the confirmation-dependent recommendations the report conveys. A few typical factors include: • the client’s goals, objectives, budget, schedule, and risk-management preferences; • the general nature of the structure involved, its size, configuration, and performance criteria; • the structure’s location and orientation on the site; and • other planned or existing site improvements, such as retaining walls, access roads, parking lots, and underground utilities.

Typical changes that could erode the reliability of this report include those that affect:• the site’s size or shape;• the function of the proposed structure, as when it’s changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse;• the elevation, configuration, location, orientation, or weight of the proposed structure;• the composition of the design team; or• project ownership.

As a general rule, always inform your geotechnical engineer of project changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered.

This Report May Not Be ReliableDo not rely on this report if your geotechnical engineer prepared it:• for a different client;• for a different project;• for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations.

Note, too, that it could be unwise to rely on a geotechnical-engineering report whose reliability may have been affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an “apply-by” date on the report, ask what it should be, and, in general, if you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying it. A minor amount of additional testing or analysis – if any is required at all – could prevent major problems.

Most of the “Findings” Related in This Report Are Professional OpinionsBefore construction begins, geotechnical engineers explore a site’s subsurface through various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing were performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgment to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team from project start to project finish, so the individual can provide informed guidance quickly, whenever needed.

This Report’s Recommendations Are Confirmation-DependentThe recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgment and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions revealed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation.

This Report Could Be MisinterpretedOther design professionals’ misinterpretation of geotechnical-engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a full-time member of the design team, to: • confer with other design-team members, • help develop specifications, • review pertinent elements of other design professionals’ plans and specifications, and • be on hand quickly whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction observation.

Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for informational purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report, but they may rely on the factual data relative to the specific times, locations, and depths/elevations referenced. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may

perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect.

Read Responsibility Provisions CloselySome client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly.

Geoenvironmental Concerns Are Not CoveredThe personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not yet obtained your own environmental information, ask your geotechnical consultant for risk-management guidance. As a general rule, do not rely on an environmental report prepared for a different client, site, or project, or that is more than six months old.

Obtain Professional Assistance to Deal with Moisture Infiltration and MoldWhile your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, none of the engineer’s services were designed, conducted, or intended to prevent uncontrolled migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists.

Copyright 2016 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any

kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent

Telephone: 301/565-2733e-mail: [email protected] www.geoprofessional.org

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