T82_Geotech Report.pdf

REPORT C OVER PAGE

Geotechnical Engineering Report

ACE-3285 RCAG UIS COMM Tower Replacement

Fredericksburg, Texas

March 24, 2022

Terracon Project No. 90225043

Prepared for:

PTSI Managed Services, Inc.

Fort Worth, TX

Prepared by:

Terracon Consultants, Inc.

San Antonio, Texas

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REPORT TOPICS

INTRODUCTION

SITE CONDITIONS

PROJECT DESCRIPTION

GEOTECHNICAL CHARACTERIZATION

GEOTECHNICAL OVERVIEW

EARTHWORK

DEEP FOUNDATIONS

MAT FOUNDATION

SEISMIC CONSIDERATIONS

LATERAL EARTH PRESSURES

CORROSIVITY

GENERAL COMMENTS

FIGURES

Note: This report was originally delivered in a web-based format. Orange Bold text in the report indicates a referenced section heading. The PDF version also includes hyperlinks which direct the reader to that section and clicking on the

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ATTACHMENTS

EXPLORATION AND TESTING PROCEDURES

SITE LOCATION AND EXPLORATION PLANS

EXPLORATION RESULTS

SUPPORTING INFORMATION

Note: Refer to each individual Attachment for a listing of contents.

http://client.terracon.com/

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INTRODUCTION

Geotechnical Engineering Report

ACE-3285 RCAG UIS COMM Tower Replacement

Site ID: T82/FKB-RCAG

Fredericksburg, Texas Terracon Project No. 90225043

March 24, 2022

INTRODUCTION

This report presents the results of our subsurface exploration and geotechnical engineering services performed for the proposed communication tower (Site ID: T82-FKB) to be located near the intersection of FM 965 and Olvera Ln. in Fredericksburg, Texas. The purpose of these services is to provide information and geotechnical engineering recommendations relative to:

■ Subsurface soil conditions ■ Foundation design and construction

■ Groundwater conditions ■ Site preparation and earthwork

■ Seismic site classification per IBC ■ Lateral earth pressures

The geotechnical engineering Scope of Services for this project included the advancement of one test boring to a depth of approximately 40 feet below existing site grades.

Maps showing the site and boring locations are shown in the Site Location and Exploration

Plan sections, respectively. The results of the laboratory testing performed on soil samples obtained from the site during the field exploration are included on the boring log and/or as separate graphs in the Exploration Results section.

SITE CONDITIONS

Item Description

Parcel Information

The project site is located near the intersection of FM 965 and Olvera Ln.

in Fredericksburg, Texas.

Site GPS: 30.38639, -98.86306

See Site Location

Existing Improvements Existing improvements include existing antennae and an ancillary equipment building.

Current Ground Cover Bare soil and gravel.

Existing Topography Relatively flat

ACE-3285 RCAG UIS COMM Tower Replacement ■ Fredericksburg, Texas

March 24, 2022 ■ Terracon Project No. 90225043

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PROJECT DESCRIPTION

Item Description

Project Description The project includes the construction of a self-supporting steel antenna on concrete foundations. The four corners of the tower will be about 20 feet apart and the overall tower height will range from 40 to 80 feet.

Maximum Loads (provided by PTSI Managed Services, Inc.)

Seismic

■ Axial: 55 kips

■ Shear: 46 kips

■ Moment: 1,550 kip-ft

60 mph Wind and 1.25” Ice

■ Axial: 100 kips

■ Shear: 19 kips

■ Moment: 607 kip-ft

120 mph Wind

■ Axial: 55 kips

■ Shear: 47 kips

■ Moment: 147 kip-ft

Grading/Slopes The proposed tower is anticipated to be placed within 2 feet of existing grade.

GEOTECHNICAL CHARACTERIZATION

We have developed a general characterization of the subsurface conditions based upon our review of the subsurface exploration, laboratory data, geologic setting and our understanding of the project. This characterization, termed GeoModel, forms the basis of our geotechnical calculations and evaluation of site preparation and foundation options. Conditions encountered at the exploration point are indicated on the individual log. The individual log can be found in the

Exploration Results section and the GeoModel can be found in the Figures section of this report.

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Model Layer Layer Name General Description

1 Clayey Gravel (GC) Brown to Tan, Medium Dense

2 Marl (rock-like) Tan, Hard

Groundwater Conditions

The boring was observed during drilling for the presence and level of groundwater. Groundwater was not observed during the drilling operations. A relatively long period may be necessary for a groundwater level to develop and stabilize in a borehole. Long term observations in piezometers or observation wells sealed from the influence of surface water are often required to define groundwater levels in materials of this type.

Groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the boring was performed. Therefore, groundwater levels during construction or at other times in the life of the structure may be higher or lower than the levels indicated on the boring log. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project.

GEOTECHNICAL OVERVIEW

The soil deposits observed at the proposed tower location consisted of approximately 4 feet of dense to very dense clayey gravel (GeoModel Layer 1) underlain by hard marl (rock-like) soils

(GeoModel Layer 2).

Two foundation alternatives could be considered for foundation support of the tower.

Option A: The tower legs can be supported on drilled shaft foundations. Groundwater was not encountered; however, the contractor should be prepared to use temporary casing to control seepage and/or downhole pumps to remove accumulated water in the drilled shaft excavations.

Where seepage is not adequately controlled, or water/drilling fluid is present in the shaft excavations, concrete should be placed using a tremie or concrete pump hose extended to within

6 inches of the shaft base. Design recommendations and construction considerations for drilled shaft foundations are provided in the Deep Foundation section. High torque, high powered

(rock) drilling equipment will be required due to the presence of Marl (rock-like).

Option B: The tower could be alternatively supported on a mat foundation system. In this case, we recommend that an over excavation be completed to accommodate and bear the mat foundation. Considering the mat foundation is planned to bear at a depth of 2 feet below existing grade, we recommend the excavation is completed to a depth of a 2 feet below existing grade, Responsive ■ Resourceful ■ Reliable 4 with the mat foundation bearing on moisture conditioned and compacted onsite soil. Due to the presence of clayey gravel, water seepage should be anticipated in the over excavation after a precipitation event and where seepage is encountered, dewatering will be required and should be addressed in advance of construction. Additional design recommendations for a mat foundation for the proposed tower are provided in the Mat Foundation section. If this option is selected, care should be taken to avoid undermining existing footings, walls, grade-supported slabs, and utilities during any over excavations necessary to remove unsuitable materials. Excavations adjacent to the existing building should not be deeper than the bottom of the existing foundation elements unless the existing foundations or walls are shored or underpinned.

The General Comments section provides an understanding of the report limitations.

EARTHWORK

Site Preparation

Site preparation would commence with removal of the granular surfacing. If the mat foundation option is selected, over excavations for removal of medium dense soils are expected so that the mat foundation can bear 2 feet below the existing grade. The following sections provide recommendations for use in the preparation of specifications for the work. Recommendations include critical quality criteria, as necessary, to render the site in the state considered in our geotechnical engineering evaluation for foundations.

Structural Fill Material Types

Structural fill should meet the following material property requirements.

Soil Type

USCS

Classification Acceptable Location for Placement

Near surface on-site soils and imported

Low plasticity fine-grained 2, 3

CL ■ Backfill above and beside mat foundations

■ General site grading

Coarse-grained

(granular)

GW, GP, GM, GC,

SW, SP, SM, SC

■ Below mat foundations in overexcavations

■ General site grading

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Soil Type

USCS

Classification Acceptable Location for Placement

1. Structural fill should consist of approved materials that are free of organic matter and debris. A sample of each material type should be submitted to the Geotechnical Engineer for evaluation prior to use on this site.

2. Fine grained material (e.g., clays) can be difficult to compact in relatively small areas (e.g., excavations for foundations). Moisture conditioning (e.g., wetting or drying) would be necessary to achieve compaction requirements if fine grained material is used as structural fill for this project.

3. By our definition, low plasticity materials should have a liquid limit of 40 or less and a plasticity index of 20 or less (ASTM D4318).

4. Specific material requirements will need to be satisfied based on intended use.

Structural Fill Compaction Requirements

Structural fill should meet the following compaction requirements.

Item Description

Maximum individual lift thickness

■ 9 inches or less in loose thickness when heavy, self-propelled compaction equipment is used

■ 4 inches or less in loose thickness when hand-guided equipment (i.e.

jumping jack or plate compactor) is used

Minimum compaction requirements

Fine-grained soils:

■ 95% of maximum

Coarse-grained soils:

■ 98% of maximum

■ If the material is a coarse sand or gravel, or of a uniform size, or has a low fines content, compaction comparison to relative density may be more appropriate. In this case, coarse-grained soils should be compacted to at least 70% relative density (ASTM D4253 and D4254).

Water content range

Fine-grained soils:

■ -2 to +3% of optimum

Coarse-grained soils:

■ Water content should be maintained at levels satisfactory for compaction to be achieved without the coarse-grained material bulking during placement or pumping when proofrolled.

1. Maximum density and optimum water content as determined using standard effort (ASTM D698).

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Grading and Drainage

Adequate drainage should be provided at the site to reduce the likelihood of an increase in moisture content of the foundation soils. Final site grading should be away from the tower to reduce the likelihood of water ponding near the structures.

Groundwater which collects in excavations should be removed as soon as possible. Removal of accumulated water from excavations in clay soil can usually be accomplished by using a sump pit and pump system. More extensive dewatering systems will be required where excavations extend below groundwater levels. The contractor is responsible for employing appropriate dewatering methods to control seepage and facilitate construction.

Earthwork Construction Considerations

Although the exposed subgrade is anticipated to be relatively stable upon initial exposure, unstable subgrade conditions could develop during general construction operations, particularly if the soils are wetted and/or subjected to repetitive construction traffic. Should unstable subgrade conditions develop, stabilization measures will need to be employed.

Construction traffic over the completed soil subgrade should be avoided to the extent practical.

The site should also be graded to prevent ponding of surface water on the prepared soil subgrades or in excavations. If the soil subgrade should become wet, or disturbed, the affected material should be removed or these materials should be scarified, moisture conditioned, and recompacted.

As a minimum, all temporary excavations should be sloped or braced as required by Occupational

Safety and Health Administration (OSHA) regulations to provide stability and safe working conditions. Temporary excavations will be required during grading operations and/or installation of utilities and foundations. Contractors, by their contract, are usually responsible for designing and constructing stable, temporary excavations and should shore, slope or bench the sides of the excavations as required, to maintain stability of both the excavation sides and bottom. All excavations should comply with applicable local, state and federal safety regulations, including the current OSHA Excavation and Trench Safety Standards.

Construction Observation and Testing

Terracon’s involvement during the construction phase of the project provides the continuity to maintain the Geotechnical Engineer’s evaluation of subsurface conditions, including assessing variations and associated design changes.

The earthwork efforts should be monitored under the direction of the Geotechnical Engineer, and should include documentation of adequate removal of vegetation, delineation of areas requiring removal or subgrade stabilization, and assessment of existing fill materials.

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Each lift of structural fill should be tested, evaluated, and reworked as necessary until approved by the Geotechnical Engineer prior to placement of additional lifts.

In areas of foundation excavations, the exposed subgrade should be evaluated under the direction of the Geotechnical Engineer. In the event that unanticipated conditions are encountered, the Geotechnical Engineer should be contacted to discuss mitigation options.

DEEP FOUNDATIONS

In our opinion, the legs of the proposed tower can be supported on individual drilled shaft foundations. Design and construction recommendations for drilled shaft foundations are presented in the following sections.

Drilled Shaft Design Recommendations

The side resistance and end bearing values provided in the following table are based on individual drilled shafts or where drilled shafts are spaced at least 3 diameters apart (center-to-center). A reduction in design parameters would be necessary if an adjacent shaft is located with 3 diameters. In designing to resist uplift loading, no more than ⅔ of the allowable side resistance values provided for compressive loading should be used along with the effective weight of the drilled shaft concrete. Buoyant unit weights of the soil and concrete should be used in the calculations below the highest anticipated groundwater elevation.

Elev. (ft)

(site datum)

Total /

Effective

Unit

Weight 1, 2

(pcf)

Estimate d

Cohesion

(psf)

Estimated

Friction

Angle

(degrees)

Allowable

Compressive

Side

Resistance

(psf)

(FS = 2)

End

Bearing

(psf)

(FS = 3)

LPILE

LPILE Soil

Model Type

Soil

Modulus ks (pci)

Soil

Strain ε50

2088-

120 Recommend neglecting upper 4 feet

2084-

125 6,000 -- 900 NR

Stiff Clay without

Free Water

1,200 0.004

2078 -

130 8,000 -- 2,000 40,000

Stiff Clay without

Free Water

1,780 0.003

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Elev. (ft)

(site datum)

Total /

Effective

Unit

Weight 1, 2

(pcf)

Estimate d

Cohesion

Estimated

Friction

Angle

(degrees)

Compressive

Side

Resistance

(psf)

(FS = 2)

End

Bearing

(psf)

(FS = 3)

LPILE

LPILE Soil

Model Type

Soil

Modulus ks (pci)

Soil

Strain ε50

1. Groundwater depth of 40 feet below ground surface suggested for calculation of effective stresses.

2. Effective unit weight, estimated cohesion, and friction angle values have no Factor of Safety applied.

3. Site friction and lateral resistance should be ignored within the upper 4 feet. In designing to resist uplift loading, 2/3 of the side friction values provided could be used along with the effective weight of the drilled shaft. Terracon should be contacted if permanent casing will be used to allow for a review of casing type and installation procedures and update axial and lateral resistance in the zone of permanent casing.

4. Drilled shafts should penetrate at least one shaft diameter into the bearing stratum when designing for allowable end bearing pressures.

5. NR = Not recommended

Lateral deflections of drilled shafts should be evaluated using an appropriate analysis procedure and would be dependent on the physical characteristics of the drilled shaft, subsurface conditions, applied loading, restraint conditions at the bottom and top of the shaft and ground slope. We can provide analyses of lateral deflections on request.

Group action for lateral resistance of shafts should be taken into account when the center-to-center spacing is less than 8 diameters. For a group of shafts oriented parallel to a lateral load, the allowable lateral resistances provided by the subsurface materials should be reduced in accordance with the following table.

Laterally Loaded Drilled Shafts – Group Reduction Factors

Shaft Spacing

(Diameters)

Leading Row

Reduction Factor

Second Row

Reduction Factor

Third or Higher Row

Reduction Factor

8D 1.0 1.0 1.0

5D 1.0 0.8 0.7

3D 0.8 0.4 0.3

1. Center-to-center spacing in the direction of loading. If the loading direction for a single row of shafts is perpendicular to the row, a group reduction factor of less than 1.0 should be used if the shaft spacing is less than 5D (i.e., all piles are located in the leading row).

The drilled shafts should have a minimum diameter sufficient to provide adequate cover over steel reinforcement. Drilled shaft diameters should not be less than 30 inches in order to accommodate temporary casing and equipment for removal of water and for concrete placement.

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Drilled shaft foundations designed and constructed as recommended in this report would be expected to experience settlement on the order of ½ inch or less (not including elastic compression of the shaft). Proper reinforcing steel should be included in the drilled shaft designs for the combined axial and lateral loading, as well as internal bending moments.

If pier caps are used, the base of the cap should extend at least 2 feet below lowest adjacent finished grade.

Drilled Shaft Construction Considerations

Groundwater was not encountered during our field exploration. However, the contractor should be prepared to use temporary casing to control seepage and/or downhole pumps to remove accumulated water in the drilled shaft excavations. Where seepage is not adequately controlled, or water/drilling fluid is present in the shaft excavations, concrete should be placed using a tremie or concrete pump hose extended to within 6 inches of the shaft base. High torque, high powered

(rock) drilling equipment will be required due to the presence of Marl (rock-like).

The sides of the drilled shaft excavation should be protected from disturbance during shaft excavation and concrete placement. The shaft bottom should be cleaned of loose or disturbed material prior to concrete placement. Concrete should be placed as soon as possible after the foundation excavation is completed to reduce the potential for disturbance.

Where temporary casing is used, care should be taken during removal of the casing as concrete is placed. During casing removal, a sufficient concrete level should be maintained to counteract hydrostatic pressure outside of the casing. Arching of the concrete, loss of seal, and other problems can occur during casing removal and result in contamination of the drilled shaft.

Placement of loose backfill or cave-in material in the perimeter annulus around the casing should not be permitted.

A Terracon representative should observe the drilled shaft excavations to evaluate the suitability of the bearing materials and to verify that conditions in the drilled shaft excavation are consistent with those encountered in the boring. If unsuitable materials are encountered at planned depths, it may be necessary to redesign (e.g., deepen) the shaft.

MAT FOUNDATION

In our opinion, consideration could be given to supporting the proposed tower on a mat foundation.

In order to support the tower on a mat foundation, we recommend over excavating soils to a depth of 2 feet bgs, as described in Mat Foundation Construction Considerations. These recommendations consider the mat foundation will bear at a depth of about 2 feet bgs on moisture conditioned and compacted onsite soil. The base of the over excavation should be evaluated, and the foundation over excavation should be deepened, to a uniform depth across the footprint

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Description Value

Required Bearing Materials On-site soil GC soil

Net Allowable Bearing Pressure 2,500 psf

Minimum Embedment below Finished Grade 24 inches

Approximate Total Settlement 1 inch or less

Estimated Differential Settlement 2/3 of total settlement

Ultimate Passive Pressure 3, 4

(equivalent fluid density)

For materials placed adjacent to foundation:

◼ Fine-grained: 285 pcf

◼ Coarse-grained: 360 pcf

Ultimate coefficient of sliding friction 4 0.4 (on coarse-grained structural fill)

1. The recommended net allowable bearing pressure is the pressure in excess of the minimum surrounding overburden pressure at the footing base elevation. Considers foundation will bear on at least 3½ feet of new, granular structural fill, extending to depth of 7 feet bgs.

2. Foundation settlement will depend upon the variations within the subsurface soil profile, the structural loading conditions, the embedment depth of the mat, the thickness of compacted fill, and the quality of the earthwork operations. Values consider the maximum loads note in the Project Description section.

3. Use of passive earth pressures requires the sides of the excavation for the mat foundation to be nearly vertical and the concrete placed neat against these vertical faces or that the foundation forms be removed and compacted structural fill be placed against the vertical footing face. .

4. Horizontal movement of the foundation must occur to mobilize passive and sliding resistance.

5. The backfill zone needs to extend outward from the base of the foundation at 60° with respect to vertical for the granular value to be applicable.

Uplift resistance of mat foundation can be developed from the effective weight of the foundation and overlying soils, and from the weight of the structure itself. The maximum allowable uplift capacity should be taken as a sum of the effective weight of soil plus the effective weight of the foundation, and dead weight of the structure, all divided by an appropriate factor of safety. A maximum total unit weight of 120 pcf could be used for existing soils or compacted backfill at this site.

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Mat Foundation Construction Considerations

Terracon should be retained to observe and evaluate the bearing materials observed in excavations. Considering the mat foundation is planned to bear at a depth of 2 feet below existing grade, we recommend the excavation is completed to a depth of a 2 feet below existing grade, with the mat foundation bearing on moisture conditioned and compacted onsite soil.

Over excavation for compacted structural fill placement below the foundation should extend laterally beyond all edges of the foundation at least 8 inches per foot of overexcavation depth below footing base elevation, and extend to a uniform elevation over the entire footprint. The overexcavation should then be backfilled up to the footing base elevation with coarse-grained (granular) structural fill as recommended in the

Earthwork section. The overexcavation and backfill procedure is illustrated in the following adjacent figure.

The base of all foundation excavations should be free of water and loose soil prior to placing structural fill or concrete. Structural fill should be placed soon after excavating to reduce bearing soil disturbance, and concrete should be placed soon after completion of the structural fill placement or excavation to suitable soils. Should the materials at bearing level become excessively dry, disturbed or saturated, the affected material should be removed prior to placing concrete.

SEISMIC CONSIDERATIONS

The seismic design requirements for buildings and other structures are based on Seismic Design

Category. Site Classification is required to determine the Seismic Design Category for a structure.

The Site Classification is based on the upper 100 feet of the site profile defined by a weighted average value of either shear wave velocity, standard penetration resistance, or undrained shear strength in accordance with Section 20.4 of ASCE 7 and the International Building Code (IBC).

Based on the soil properties encountered at the site and as described on the exploration logs and results, it is our professional opinion that the Seismic Site Classification is C. Subsurface explorations at this site were extended to a maximum depth of 40 feet. The site properties below the boring depth to 100 feet were estimated based on our experience and knowledge of geologic conditions of the general area. Additional deeper borings or geophysical testing may be performed to confirm the conditions below the current boring depth.

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LATERAL EARTH PRESSURES

Design Parameters

Structures with unbalanced backfill levels on opposite sides should be designed for earth pressures at least equal to values indicated in the following table. Earth pressures will be influenced by structural design of the walls, conditions of wall restraint, final grades or sloping of ground adjacent to the walls, surcharges, methods of construction and/or compaction and the strength of the materials being restrained. Two wall restraint conditions are shown in the diagram below. Active earth pressure is commonly used for design of free-standing cantilever retaining walls and assumes wall movement. The “at-rest” condition assumes no wall movement and is commonly used for basement walls, loading dock walls, or other walls restrained at the top. The recommended design lateral earth pressures do not include a factor of safety and do not provide for possible hydrostatic pressure on the walls (unless stated). The recommended design lateral earth pressures provided in this section are for cast-in-place, reinforced concrete walls only, and are not applicable to other wall systems (e.g., segmental block, landscaping walls, etc.).

Lateral Earth Pressure Design Parameters

Earth Pressure

Condition

Coefficient for

Backfill Type

Surcharge

Pressure 2, 3, 4

Effective Fluid Pressures (psf) 2, 4, 5, 6

Drained Undrained

Active (Ka)

Granular: 0.33

Cohesive: 0.42

(0.33)S

(0.42)S

(40)H

(50)H

(80)H

(85)H

At-Rest (Ko)

Granular: 0.50

Cohesive: 0.59

(0.50)S

(0.59)S

(60)H

(70)H

(90)H

(95)H

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Passive (Kp)

Granular: 3.0

Cohesive: 2.4

(360)D

(285)D

(235)D

(200)D

Sliding Resistance

Ultimate coefficient of sliding friction for granular bearing soils: 0.4

1. For active earth pressure, wall must rotate about base, with top lateral movements 0.002 H to 0.004 H, where H is wall height. For passive earth pressure, wall must move horizontally to mobilize resistance

2. Considers a horizontal ground inclination uphill of the wall, and a horizontal ground inclination downhill of the wall.

3. Uniform surcharge, where S is surcharge pressure.

4. Loading from heavy compaction equipment is not included.

5. No safety factor is included in these values. H value is used for active and at-rest pressure computations from the top of wall. D value (not shown on figure) is used for passive pressure computations and is depth of foundation embedment below lowest grade at base of wall.

6. . In order to achieve “Drained” conditions, follow guidelines in the Below Grade Walls Subsurface

Drainage section. “Undrained” conditions are recommended when drainage behind walls is not incorporated into the design or where walls will be submerged during flooding events.

Backfill placed against structures should consist of granular soils or low plasticity cohesive soils.

For the granular values to be valid, the granular backfill must extend out and up from the base of the wall at an angle of at least 45 and 60 degrees from vertical for the active and passive cases, respectively.

CORROSIVITY

The table below lists the results of laboratory soluble sulfate, soluble chloride, electrical resistivity, and pH testing. The values may be used to estimate potential corrosive characteristics of the on-site soils with respect to contact with the various underground materials which will be used for project construction.

Corrosivity Test Results Summary

Boring

Sample

Depth

(feet)

Soil Description

Soluble

Sulfate

(ppm)

Soluble

Chloride

(ppm)

Electrical

Resistivity

(Ω-cm) pH

B-1 0-1.5 Clayey Gravel

(GC)

<25 20 4620 8.5

Results of water-soluble sulfate testing indicate that samples of the on-site soils have an exposure class of S0 when classified in accordance with Table 19.3.1.1 of the American Concrete Institute

(ACI) Design Manual. Selection of concrete type and mix design are the responsibility of the foundation designer.

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The pH, sulfates, sulfides, total dissolved salts, oxidation-reduction potential, and chlorides can affect the aggressiveness of corrosion to buried metal structures. These test results are provided to assist in determining the type and degree of corrosion protection that may be required. We recommend that a certified corrosion engineer be employed to determine the need for corrosion protection and to design appropriate protective measures.

GENERAL COMMENTS

Our analysis and opinions are based on our understanding of the project, the geotechnical conditions in the area, and the data obtained from our site exploration. Natural variations will occur between exploration point locations or due to the modifying effects of construction or weather.

The nature and extent of such variations may not become evident until during or after construction.

Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon should be retained to provide observation and testing services during grading, excavation, foundation construction, and other earth-related construction phases of the project. If variations appear, we can provide further evaluation and supplemental recommendations. If variations are noted in the absence of our observation and testing services on-site, we should be immediately notified so that we can provide evaluation and supplemental recommendations.

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

Our services and any correspondence or collaboration through this system are intended for the sole benefit and exclusive use of our client for specific application to the project discussed and are accomplished in accordance with generally accepted geotechnical engineering practices with no third party beneficiaries intended. Any third party access to services or correspondence is solely for information purposes to support the services provided by Terracon to our client.

Reliance on the services and any work product is limited to our client, and is not intended for third parties. Any use or reliance of the provided information by third parties is done solely at their own risk. No warranties, either express or implied, are intended or made.

Site characteristics as provided are for design purposes and not to estimate excavation cost. Any use of our report in that regard is done at the sole risk of the excavating cost estimator as there may be variations on the site that are not apparent in the data that could significantly impact excavation cost. Any parties charged with estimating excavation costs should seek their own site characterization for specific purposes to obtain the specific level of detail necessary for costing.

Site safety, and cost estimating including, excavation support, and dewatering requirements/design are the responsibility of others. If changes in the nature, design, or location

Responsive ■ Resourceful ■ Reliable 15 of the project are planned, our conclusions and recommendations shall not be considered valid unless we review the changes and either verify or modify our conclusions in writing.

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FIGURES

Contents:

GeoModel

-5

D E

P T

H B

E L

O W

G R

A D

E

F ee

t) ACE-3285 RCAG UIS Comm Tower Replacement (T82/FKB-RCAG) Fredericksburg, TX Terracon Project No. 90225043

Layering shown on this figure has been developed by the geotechnical engineer for purposes of modeling the subsurface conditions as required for the subsequent geotechnical engineering for this project.

Numbers adjacent to soil column indicate depth below ground surface.

NOTES:

B-1

GEOMODEL

This is not a cross section. This is intended to display the Geotechnical Model only. See individual logs for more detailed conditions.

LEGEND

Clayey Gravel

Weathered Limestone

Model Layer General DescriptionLayer Name

Brown to Tan, Medium Dense1

Tan, Hard2

Clayey Gravel (GC)

Marl (rock-like)

ATTACHMENTS

Responsive ■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 1 of 2

EXPLORATION AND TESTING PROCEDURES

Field Exploration

Number of Borings Boring Depth (feet) Planned Location

1 40 Antenna tower

Boring Layout and Elevations: Terracon used a handheld GPS unit to locate the field exploration point based on the provided boring coordinates. The ground surface elevation at the boring location was obtained by Terracon personnel using a surveyor’s level and rod referencing the finished floor elevation of the building north of the boring. An elevation of 100 feet (Terracon project datum) was assigned to this benchmark. The boring elevation on the boring log was rounded to the nearest ½ foot. The location and elevation of the boring should be considered approximate and accurate only to the degree implied by the means and methods used to define them.

Subsurface Exploration Procedures: The borings were drilled with a truck-mounted drilling rig using continuous flight solid-stem augers. Soil sampling was performed using thin-walled tube and split-barrel sampling procedures. In the thin-walled tube sampling procedure, a thin-walled, seamless steel tube with a sharp cutting edge is pushed hydraulically into the soil to obtain a relatively undisturbed sample. In the split-barrel sampling procedure, a standard 2-inch outer diameter split-barrel sampling spoon is driven into the ground by a 140-pound automatic hammer falling a distance of 30 inches. The number of blows required to advance the sampling spoon the last 12 inches of a normal 18-inch penetration is recorded as the Standard Penetration Test (SPT) resistance value. The SPT resistance values, also referred to as N-values, are indicated on the boring logs at the test depths. The samples were placed in appropriate containers and taken to our laboratory for testing. We observed and recorded groundwater levels during, and shortly after drilling and sampling. The borings were backfilled with auger cuttings after drilling.

The drill crew prepared a field log of each boring to record field data including visual descriptions of the materials encountered during drilling as well as the driller’s interpretation of the subsurface conditions between samples. The boring logs included with this report represent an interpretation of the subsurface conditions at each boring location based on field and laboratory data, and observation of the samples.

Laboratory Testing

In the laboratory, water content tests were performed on portions of the recovered samples. The dry unit weight of intact, thin-walled tube samples was determined. Unconfined compressive

Responsive ■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 2 of 2 strength and hand penetrometer tests were performed to estimate the consistency of select samples of fine-grained soils. Atterberg Limits, particle size analysis, and one-dimensional consolidation tests were performed on Sample 3. The results of the laboratory tests are shown on the boring logs at their corresponding sample depths and/or as separate graphs in Exploration

Results.

The samples were described in the laboratory based on visual observation, texture and plasticity, and the laboratory testing described above. The descriptions of the soils indicated on the boring logs are in general accordance with the General Notes, Unified Soil Classification System (USCS) summarized and included in Supporting Information.

SITE LOCATION AND EXPLORATION PLAN

Site Location

Exploration Plan

Utility Map

Note: All attachments are one page unless noted above.

SITE LOCATION

ACE-3285 RCAG UIS Comm Tower Replacement (T82/FKB-RCAG) ■ Fredericksburg, TX

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

EXPLORATION PLAN

ACE-3285 RCAG UIS Comm Tower Replacement (T82/FKB-RCAG) ■ Fredericksburg, TX

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS

NOT INTENDED FOR CONSTRUCTION PURPOSES

AERIAL PHOTOGRAPHY PROVIDED

BY MICROSOFT BING MAPS

2'

18"

18"

18"

18"

2'

2'

2'2'

Project No.

Scale:

Date:

File No.

FIG. No.Results Diagram

FAA T82/FKB Site Fredericksburg, Texas 1

N e electric line/grounding

03221025 1:16

MAR 2022

FAA MC

tc telecom/antenna cable boring utility vault

EXPLORATION RESULTS

Boring Log

Grain Size Distribution

Corrosivity

3-4-6 N=10

6-8-11 N=19

50/2"

50/2"

50/2"

50/2"

50/2"

50/0"

50/0"

50/0"

50/0"

15.1

8.6

8.5

5.8

7.6

7.7

5.9

12.5

13.1

9.6

6.4

CLAYEY GRAVEL (GC), brown to tan, dense to very dense

MARL, tan, hard, (rock-like)

Boring Terminated at 40 Feet

4.0

40.0

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

T H

IS

B

O R

IN

G

L O

G

IS

N O

T V

A

LI

D

IF

S E

P A

R A

T E

D F

R O

M O

R

IG

IN

A

L R

E P

O R

T

G E

O S

M A

R T

L O

G -N

O W

E

LL

A

C E

-3

R

C A

G U

IS

.G

P J

T E

R R

A C

O N

_D A

T A

T E

M P

LA

T

E .G

D T

/2

/2

D E

P T

H

F t.)

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S STRENGTH TEST

F

IE

LD

T

E S

T R

E S

U

LT

S

W A

T E

R C

O N

T E

N T

D R

Y U

N

IT

W E

IG

H

T pc f)

LL-PL-PI

ATTERBERG

LIMITSLOCATION See Exploration Plan

Latitude: 30.3862° Longitude: -98.8631°

G R

A P

H

IC

L O

G

M O

D E

L

LA

Y E

R

DEPTH ELEVATION (Ft.)

Surface Elev.: 2088 (Ft.)

Advancement Method:

Air Rotary

Abandonment Method:

Boring backfilled with auger cuttings upon completion.

Notes:

Project No.: 90225043

Drill Rig: CME 75

BORING LOG NO. B-1

PTSI Managed Services Inc. (Parsons)CLIENT:

Fort Worth, TX

Driller: J.V.

Boring Completed: 02-25-2022

PROJECT: ACE-3285 RCAG UIS Comm Tower Replacement (T82/FKB-RCAG)

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

FM 965 and Olvera Ln.

Fredericksburg, TX

SITE:

Boring Started: 02-25-2022

6911 Blanco Rd San Antonio, TX

WATER LEVEL OBSERVATIONS

No free water observed

S T

R A

IN

C O

M P

R E

S S

IV

E

S T

R E

N G

T H

(t sf

T E

S T

T Y

P E

P E

R C

E N

T F

IN

E

S

S A

M P

LE

T

Y P

E

0.0010.010.1110100

3/4 1/23/8 30 403 60

HYDROMETERU.S. SIEVE OPENING IN INCHES

16 20

U.S. SIEVE NUMBERS

44 10063 2 10 14 506 2001.5 81 140

P E

R C

E N

T F

IN

E

R B

Y W

E

IG

H T

P E

R C

E N

T C

O A

R S

E R

B Y

W E

IG

H

T

GRAIN SIZE DISTRIBUTION

ASTM D422 / ASTM C136

6911 Blanco Rd San Antonio, TX

PROJECT NUMBER: 90225043

SITE: FM 965 and Olvera Ln.

Fredericksburg, TX

PROJECT: ACE-3285 RCAG UIS Comm Tower Replacement

(T82/FKB-RCAG)

CLIENT: PTSI Managed Services Inc.

(Parsons) Fort Worth, TX

LA

B

O R

A T

O R

Y T

E S

T S

A R

E N

O T

V A

LI

D

IF

S

E P

A R

A T

E D

F R

O M

O R

IG

IN

A L

R E

P O

R T

G R

A

IN

S

IZ

E : U

S C

S

A

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-3

R

C A

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IS

.G

P J

T E

R R

A C

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_D A

T A

T E

M P

LA

T

E .G

D T

/2

/2

B-1 fine coarse finemedium

COBBLES

GRAVEL SAND

SILT OR CLAY

D30

D60

BORING ID

#4 #200

68.5 33.8

CC

CU

coarse

D10

34.7 33.80 - 1.5

1.719

Sieve

REMARKS

SOIL DESCRIPTION

% Finer% Finer SieveSieve% Finer

USCS% CLAY% FINES% SILT% SAND% GRAVEL% COBBLESDEPTH

COEFFICIENTS

GRAIN SIZE

Project Name: 90225043 Client Sample ID: B-1 0 - 1.5

Collection Date: 3/10/2022 Matrix: SOLID

Analyses Result Units Date AnalyzedReport Limit

Client: Terracon Consultants, Inc.

Lab Order: 2203035

Lab ID: 2203035-01A

Dilution

Date: 17-Mar-22

Project ID:

ALAMO ANALYTICAL LABORATORIES, LTD.

Analytical Results Report

SULFIDE IN SOIL C105 Analyst: YK Sulfide 14-Mar-220. 0=neg,1=pos 10.

OXIDATION-REDUCTION POTENTIAL D1498 Analyst: YK Oxidation-Reduction Potential 14-Mar-22-180. millivolts 12.9

RESISTIVITY SM2510B Analyst: YK Resistivity 15-Mar-220.0001 ohms-cm 14620

Resistivity 15-Mar-220.0001 ohms-cm 1

CORROSIVITY BY PH SW9045D Analyst: YK pH at 25 o C 15-Mar-220.1 pH Units 18.5

TEX-620-J TX620J Analyst: YK Chloride 15-Mar-225 mg/Kg 120

TEX-620-J TX620J Analyst: YK Sulfate 15-Mar-2225 mg/Kg 1< 25

Approved by: Reddy Gosala, Laboratory Direc

Note: The analysis contained in this report applies only to the samples tested and for the exclusive use of the addressed client. Reproduction of this report wholly or in part requires written permission of the client.

Report of Laboratory Analysis

SUPPORTING INFORMATION

General Notes

Unified Soil Classification System

0.25 to 0.50

> 4.00

2.00 to 4.00

1.00 to 2.00

0.50 to 1.00 less than 0.25

Unconfined Compressive Strength Qu, (tsf)

Shelby Tube Split Spoon

Trace

PLASTICITY DESCRIPTION

Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations.

DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

GENERAL NOTES

> 30

11 - 30

1 - 10Low

Non-plastic

Plasticity Index

#4 to #200 sieve (4.75mm to 0.075mm

Boulders

12 in. to 3 in. (300mm to 75mm)Cobbles

3 in. to #4 sieve (75mm to 4.75 mm)Gravel

Sand

Passing #200 sieve (0.075mm)Silt or Clay

Particle Size

Water Level After a Specified Period of Time

Water Level After a Specified Period of Time

Water Initially Encountered

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

GRAIN SIZE TERMINOLOGY

RELATIVE PROPORTIONS OF FINESRELATIVE PROPORTIONS OF SAND AND GRAVEL

DESCRIPTIVE SOIL CLASSIFICATION

LOCATION AND ELEVATION NOTES

SAMPLING WATER LEVEL FIELD TESTS

N

(HP)

(T)

(DCP)

UC

(PID)

(OVA)

Standard Penetration Test Resistance (Blows/Ft.)

Hand Penetrometer

Torvane

Dynamic Cone Penetrometer

Unconfined Compressive Strength

Photo-Ionization Detector

Organic Vapor Analyzer

Medium

0Over 12 in. (300 mm)

>12

5-12

<5

Percent of Dry Weight

TermMajor Component of Sample

Modifier

With

Trace

Descriptive Term(s) of other constituents

>30Modifier

<15

Percent of Dry Weight

Descriptive Term(s) of other constituents

With 15-29

High

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

Standard Penetration or N-Value

Blows/Ft.

Descriptive Term (Density)

CONSISTENCY OF FINE-GRAINED SOILS

Hard

15 - 30Very Stiff> 50Very Dense

8 - 15Stiff30 - 50Dense

4 - 8Medium Stiff10 - 29Medium Dense

2 - 4Soft4 - 9Loose

0 - 1Very Soft0 - 3Very Loose

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

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

STRENGTH TERMS

> 30

Descriptive Term (Consistency)

Standard Penetration or N-Value

Blows/Ft.

RELATIVE DENSITY OF COARSE-GRAINED SOILS

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

Density determined by Standard Penetration Resistance

UNIFIED SOIL CLASSIFICATION SYSTEM

UNIFIED SOIL C LASSIFIC AT ION SYSTEM

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

Group Symbol

Group Name B

Coarse-Grained Soils:

More than 50% retained on No. 200 sieve

Gravels:

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

Clean Gravels:

Less than 5% fines C

Cu 4 and 1 Cc 3 E GW Well-graded gravel F

Cu 4 and/or [Cc<1 or Cc>3.0] E GP Poorly graded gravel F

Gravels with Fines:

More than 12% fines C

Fines classify as ML or MH GM Silty gravel F, G, H

Fines classify as CL or CH GC Clayey gravel F, G, H

Sands:

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

Clean Sands:

Less than 5% fines D

Cu 6 and 1 Cc 3 E SW Well-graded sand I

Cu 6 and/or [Cc<1 or Cc>3.0] E SP Poorly graded sand I

Sands with Fines:

More than 12% fines D

Fines classify as ML or MH SM Silty sand G, H, I

Fines classify as CL or CH SC Clayey sand G, H, I

Fine-Grained Soils:

50% or more passes the No. 200 sieve

Silts and Clays:

Liquid limit less than 50

Inorganic:

PI 7 and plots on or above “A” line J

CL Lean clay K, L, M

PI 4 or plots below “A” line J ML Silt K, L, M

Organic:

Liquid limit - oven dried

0.75 OL

Organic clay K, L, M, N

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

Silts and Clays:

Liquid limit 50 or more

Inorganic:

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

PI plots below “A” line MH Elastic Silt K, L, M

Organic:

Liquid limit - oven dried

0.75 OH

Organic clay K, L, M, P

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

Highly organic soils: Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-inch (75-mm) sieve.

B If field sample contained cobbles or boulders, or both, add “with cobbles or boulders, or both” to group name.

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

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

E Cu = D60/D10 Cc =

DxD

)(D

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

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

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

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

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

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

L If soil contains 30% plus No. 200 predominantly sand, add

“sandy” to group name.

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

“gravelly” to group name.

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

O PI 4 or plots below “A” line.

P PI plots on or above “A” line.

Q PI plots below “A” line.