2-2025-068 FerronFairgrounds Geo 11172025.pdf

2025-068_FERRONFAIRGROUNDS_GEO_11172025 November 17, 2025

GEOTECHNICAL DESIGN

REPORT

FERRON FAIRGROUNDS

EVENT CENTER

FERRON, UT

NOVEMBER 17, 2025

PRACTICAL SOLUTIONS

FOR A COMPLEX WORLD

Moab Geotechnical Group

11850 S Highway 191, Ste. B3

TEL: (435) 210-8282 www.moabgeo.com

November 17, 2025

Jones & DeMille Engineering c/o Wyatt Hansen, PE

1675 South Highway 10

Price, UT 84501

Mr. Hansen, Moab Geotechnical Group LLC (MGG) is pleased to submit this geotechnical design report in support of the proposed Ferron Fairgrounds Event Center in Ferron, Utah. This report has been revised from its original version, dated September 8, 2025, to reflect updated structural loads provided by Jones & DeMille Engineering on October

31, 2025 and additional borings performed on November 13, 2025. The investigation was performed to evaluate subsurface conditions and provide design-level recommendations for foundation systems, slab-on-grade construction, and general site preparation.

This report summarizes the findings from our field exploration and laboratory testing, and presents recommendations for shallow foundation design, estimated settlements, lateral earth pressures, and construction considerations. All recommendations are intended to support the design and construction of the planned ~37,000-square-foot pre-engineered metal building (PEMB) and associated site improvements.

We appreciate the opportunity to support Jones & DeMille Engineering and Ferron City on this important community project. If you have any questions or require additional information, please do not hesitate to contact us.

Sincerely, Taylor Hall, PE

Principal

FERRON FAIRGROUNDS EVENT CENTER 2025-068

GEOTECHNICAL REPORT November 17, 2025 i

1 INTRODUCTION

1.1 Scope of Services

1.2 Project Description

1.3 Existing and Historic Information

2 SITE CHARACTERIZATION

2.1 Exploratory Test Pits

2.2 Exploratory Borings

2.3 Dynamic Cone Penetrometer

2.4 Laboratory Testing

2.5 Surface Conditions

2.6 Subsurface Conditions

2.7 Groundwater

3 GEOLOGICAL AND GEOTECHNICAL HAZARDS AND FINDINGS

3.1 Geologic Setting

3.2 Landslide and Slope Stability

3.3 Radon

3.4 Problematic Soils

3.4.1 Collapsible Soils

3.4.2 Expansive Soils

3.4.3 Soluble Soils and Rock

3.5 Reactive Soils

3.6 Piping and Erosion

3.7 Shallow Bedrock

3.8 Seismic

4 GEOTECHNICAL DESIGN RECOMMENDATIONS

4.1 Seismic Design Parameters

4.2 Lateral Earth Pressures

4.3 Foundations

4.3.1 Footings

4.3.2 Interior Slab on Grade

4.3.3 Sliding Resistance

4.3.4 Deep Foundations – Caissons

ii

4.4 Vapor Reduction

4.5 Drainage and Landscaping

4.6 Pavement

4.7 Concrete Flatwork

5 CONSTRUCTION CONSIDERATIONS

5.1 Site Preparation

5.2 Subgrade Preparation

5.3 Fill Placement

5.3.1 Structural Fill

5.4 Utilities

5.5 Excavations

6 ADDITIONAL SERVICES

6.1 Project Progression

6.2 Plan and Specification Review

6.3 Testing and Observation Services

7 LIMITATIONS

REFERENCES

Exhibits

Exhibit 2-1 Infiltration Rates and Hydraulic Conductivity

Exhibit 2-2 DCP Correlations

Exhibit 3-1 Collapse Test Results

Exhibit 3-2 Corrosion and Resistivity Test Results

Exhibit 4-1 Seismic Design Parameters

Exhibit 4-2 Summary of Lateral Earth Pressures

Figures

Figure 1 Vicinity Map

Figure 2 Explorations Map

Figure 3 Geologic Map

Appendices

Appendix A Test Pit and Boring Logs

Appendix B Laboratory Test Results

Appendix C Field Test Results

1 INTRODUCTION

This report provides design recommendations and construction considerations for the proposed Ferron Fairgrounds

Event Center in Ferron, Utah. The recommendations are based on findings from our field investigation and subsequent laboratory testing. Should the structure or site development plans change from what is described herein, Moab Geotechnical Group (MGG) should be contacted to evaluate the applicability of the recommendations provided.

1.1 Scope of Services

The following scope of services was performed in accordance with the Professional Services Agreement executed on July 28, 2025, between MGG and Jones & DeMille Engineering, Inc., in support of the design-level geotechnical investigation:

• Excavation and logging of three (3) test pits using a mini excavator provided by MGG to characterize subsurface conditions and advance two borings in the vicinity of the proposed structure,

• Performance of four (4) Dynamic Cone Penetrometer (DCP) tests to estimate in situ soil strength and bearing resistance.

• Collection of representative bulk and disturbed soil samples for laboratory classification and characterization.

• Laboratory testing including moisture content, dry density, Atterberg limits, gradation analysis, and corrosion potential.

• Preparation of this geotechnical design report summarizing field and laboratory findings and providing recommendations for:

Additional services to support construction are recommended to verify subsurface conditions and ensure consistency with design assumptions. Subsurface conditions are inherently variable and may change over short distances.

1.2 Project Description

This investigation supports the design and construction of a new ~37,000-square-foot pre-engineered metal building

(PEMB) at the Ferron City Fairgrounds. The structure is anticipated to span approximately 160 feet with 25-foot bay spacing, resulting in original estimated column loads from 80 to 100 kips. This revised report addresses updated structural loads, including combined column loads up to 203 kips. The final building location may be within the footprint of the original barn or relocated inside the existing horse track.

Associated site improvements may include paved access roads, parking areas, concrete flatwork, and utility infrastructure.

1.3 Existing and Historic Information

Publicly available aerial imagery and site history were reviewed to assess past development and land use. The site has historically served agricultural and community functions, including use as a fairgrounds and livestock facility.

A previous barn structure was destroyed by fire, and remnants of past development may influence subsurface conditions.

The site appears relatively undeveloped in terms of modern infrastructure, with the exception of the horse track and utility corridors. A current aerial image is provided in Figure 2.

2 SITE CHARACTERIZATION

Moab Geotechnical Group (MGG) conducted a geotechnical investigation to evaluate subsurface conditions at the

Ferron Fairgrounds Event Center site. The investigation included test pit excavation, borings, in situ penetration testing, and laboratory testing of recovered soil samples to characterize engineering properties. Explorations were performed across the proposed building footprint, drive lanes, parking areas, and stormwater features. Approximate exploration locations are shown in Figure 2.

2.1 Exploratory Test Pits

Three (3) test pits were excavated within and near the vicinity of the proposed structure, see Figure 2. Test pits were excavated using a Yanmar Vio 35 excavator with a 12-inch bucket. Sampling was performed to classify subsurface materials and evaluate their strength and consistency. Undisturbed samples were collected using 3-inch shelby tubes pushed with the excavator and AWJ rods and head adaptor for the shelby tubes. Disturbed samples were collected in sealed plastic bags or placed in 5-gallon buckets at the time of excavation. Upon completion, each test pit was backfilled with excavation spoils.

A description of the subsurface materials encountered is provided in Section 2.6. A graphical summary of the geotechnical test pit logs is included in Appendix A.

The latitude and longitude coordinates of the test pits were estimated using handheld GPS devices with a reported accuracy of approximately 10 feet. Surface elevations were estimated based on the USGS 1/3 arc-second digital elevation model (USGS, 2024).

2.2 Exploratory Borings

MGG retained South Slope Drilling of Altonah, Utah to perform the exploratory borings. Two (2) borings were advanced in the vicinity of the proposed structure using a track-mounted CME-55 drill rig equipped with 6-inch outer diameter hollow-stem augers. The two borings were advanced to about 15 feet below existing site grade.

Disturbed samples were collected using standard split spoon (SPT) and modified California samplers (2.5-inch inner diameter) driven with a 140-lb automatic hammer.

The borings were logged in the field by a licensed professional engineer. Representative samples were collected for laboratory testing and classification. Upon completion, the boreholes were backfilled with cuttings. A graphical summary of the borings is provided in Appendix A. Boring locations were recorded using handheld GPS units with an estimated horizontal accuracy of ±10 feet. Elevations were estimated using a USGS digital elevation model with a resolution of 1/3 arc-second.

2.3 Dynamic Cone Penetrometer

Three Dynamic Cone Penetrometer (DCP) tests were conducted in accordance with ASTM D6951 using a hand-held 17.6-pound drop hammer and sacrificial 60° cone tips with a diameter of 0.79 inches. The purpose of the testing was to characterize the strength and stiffness of near-surface soils across the site.

DCP testing provides empirical correlations to California Bearing Ratio (CBR), elastic modulus, and allowable bearing capacity, as summarized in Exhibit 2-2. Correlation charts and interpreted plots are presented in Appendix

C.

Exhibit 2-2 DCP Correlations

Parameter Correlation Reference

Depth per Impact (DPI) Calculated in inches/blow N/A

California Bearing Ratio (CBR) CBR (%) = 292 / (DPI*25.4)1.12

[DPI in in/blow]

ASTM, 2023

Elastic Modulus EDPI (MPa) = 103.04758-[1.06166log(DPI)]

[DPI in mm/blow]

Lockwood et al., 1992

Bearing Capacity q (psi) = 3.794 *CBR0.664 Packard, R.G., 1973

2.4 Laboratory Testing

Laboratory testing was performed on select soil samples by MGG and by Intermountain GeoEnvironmental

Services, Inc. (IGES), of South Salt Lake, Utah. The testing program included the following:

• Index Testing (Moisture Content, ASTM D2216; Particle Size Distribution – Sieve Analysis, ASTM

D6913; Fines Content, ASTM D1140);

• Standard Test Methods for 1-D Swell or Collapse of Soils (ASTM D4546)

• Compaction Characteristics (Modified Proctor, ASTM D1557);

• Corrosion and Resistivity (Minimum Resistivity, AASHTO T 288; Soil pH, AASHTO T 289; Soluble

Chloride, HACH 8113; Soluble Sulfate, HACH 8051).

Results of the laboratory tests are provided in Appendix B. Select properties are also summarized on the test pit logs provided in Appendix A.

2.5 Surface Conditions

Surface conditions across the footprint of the proposed structure, see Figure 2, ranges from imported granular fill used as a parking lot and driving surface around the existing structure. Surface conditions within the existing structure consist of silty sand and sandy silt material with manure and hay debris scattered about. The site grades approximately north to south with a slight west to east trajectory. The existing structure appears to be supported by

18- to 24-inch caissons.

2.6 Subsurface Conditions

Subsurface conditions vary across the proposed structure. Undocumented fill was observed in TP-01 and is understood to be span the southern half of the proposed structure. According to conversations with City and the

Special Services District, the fill was placed to provide the parking and driving area south of the existing structure.

The undocumented fill was measured to be about seven (7) feet thick at TP-01 and eight (8) feet thick in B-01. It is expected for the thickness of the fill to taper (become shallower) towards the north. Native soils consist of clayey sand, sandy silt, and silty clay in the near surface and transition to silty gravel overlying the bedrock encountered at 11 feet in each boring. Native fine-grained soils are in a very loose to loose and soft to medium stiff state while native granular soils are in a loose to very dense state The undocumented fill was measured to be in a loose to very dense state.

2.7 Groundwater

Groundwater was found at depths of about 11 feet below existing site grade in each of the borings advanced. The groundwater appears to be located at the top of the bedrock. Groundwater levels are anticipated to fluctuate with precipitation events and nearby agricultural practices. Groundwater is not expected to impact the proposed improvements.

3 GEOLOGICAL AND GEOTECHNICAL HAZARDS AND FINDINGS

Geological and geotechnical hazards are present at nearly all sites due to the complex processes that form and modify soil and rock. The Ferron Fairgrounds site lies within the Colorado Plateau region, where hazards such as collapsible soils, soluble minerals, and radon are common. This section evaluates the potential impact of these hazards on the proposed development based on site-specific findings and regional data.

3.1 Geologic Setting

The site is mapped within the Blue Gate Member of the Mancos Shale (Kbg), a Cretaceous marine shale unit.

Overlying this bedrock are Quaternary alluvial deposits (Qal) consisting of valley fill and terrace gravels.

Subsurface conditions encountered during test pit excavation were generally consistent with this mapping, with silty sands and sandy silts observed above suspected shale bedrock.

3.2 Landslide and Slope Stability

According to the Utah Geological Hazards Portal, the site is located in an area of low to very low landslide susceptibility. The adjacent wash and flat topography suggest minimal risk of slope instability. However, localized erosion or wash migration during high-intensity storm events remains a possibility. Proper drainage design and grading under the supervision of a licensed Civil Engineer are recommended to mitigate this risk.

3.3 Radon

Radon is a common geologic hazard throughout the Colorado Plateau region due to the natural decay of radioactive-bearing minerals found in bedrock and alluvial soils. This colorless, odorless gas can accumulate in enclosed structures and poses a health risk with prolonged exposure.

Where the improvements consist of enclosed spaces, new construction should consider current ANSI/AARST

Radon Standards, which establish minimum prescriptive requirements to address radon and other hazardous soil gases. The most recent standard for new construction of multifamily, school, commercial, and mixed-use buildings was published in 2023 (ANSI/AARST, 2023) and provides guidance on reducing indoor radon levels. Additional recommendations to address radon can be provided upon request.

3.4 Problematic Soils

Problematic soils generally consist of soluble, collapsible, and expansive soils in the Southwest and Colorado

Plateau Regions. The following subsections detail each hazard as it relates to the Project.

3.4.1 Collapsible Soils

Collapsible soils are soils that have the potential to undergo significant volumetric change once loaded or wetted.

Generally, the soils are deposited during flood, debris flow, or landslides and can become cemented from naturally occurring processes. Once wetted, or loaded beyond the compressive strength of the soil, the soils can break down and collapse. This behavior is often non-uniform and may result in differential settlement.

The native soils observed in the exploratory test pits has the potential to be collapsible. Collapse potential was evaluated in accordance with ASTM D4546. Results are summarized in Exhibit 3-1, and complete data is presented in Appendix B. The recommendations presented in Sections 4.0 and 5.0 should be followed to mitigate the potential effects of collapsible soils on proposed improvements.

Exhibit 3-1 Collapse Test Results

Exploration Sample ID Depth (ft) Inundation Stress (psf) Collapse (%)

TP-03 ST-02 2 – 3 1,500 2.7

TP-03 ST-03 5 – 6 1,000 0.7

3.4.2 Expansive Soils

Expansive soils generally occur when cohesive soils or weathered shales become wet. The plate-like nature of the material and its mineralogy determines how expansive these materials are. Wetting due to irrigation practices, site drainage, precipitation, and utilities often occurs irregularly around structures and can lead to differential movement of expansive soils. This differential settlement if often presented by ‘heaving’ flatwork, cracking foundations, jamming windows and doors, and inoperable utilities. Expansive soils were not observed during the field exploration.

3.4.3 Soluble Soils and Rock

Soluble soil and rock are a hazard of known significance in the Colorado Plateau area. Soluble soil and rock are a result of prehistoric ocean environments that have resulted in numerous soluble minerals that have been transported, accumulated, and redistributed throughout the area. These minerals are chaotically transported up to surficial soils through springs, flooding events, and fluctuations in the groundwater. Given the depositional nature of the minerals, the hazard is difficult to address due to its unpredictable presence in the subsurface.

During this investigation, white, chalky material—suspected to be calcium carbonate—was observed in several test pits at various depths, with an estimated volume of less than 5 percent. Calcium carbonate is considered moderately soluble, and its dissolution may reduce cementation and contribute to ground softening or volume loss, particularly where present in higher concentrations. Based on the limited observed quantity of potentially soluble material, the potential for soluble soils or rock to adversely impact the proposed improvements is considered low. If horizons or pockets of white, potentially soluble materials—such as salts or gypsum—are encountered during construction, MGG should be contacted for further evaluation.

3.5 Reactive Soils

Potentially corrosive environments exist in nearly every soil and rock regime. Corrosion can damage unprotected steel and concrete. Corrosion and resistivity testing was conducted on select samples obtained during the field investigation. Test results are summarized in Exhibit 3-2 and detailed in Appendix B.

Exhibit 3-2 Corrosion and Resistivity Test Results

Exploration Sample

ID

Depth (ft) pH

Soluble

Sulfate

(ppm)

Soluble

Chloride

(ppm)

Minimum

Resistivity

(ohm-cm)

TP-03 BULK-01 0-3 8.4 510 117 1,057

The minimum measured resistivity of 1,057 ohm-cm indicates a corrosive to highly corrosive environment for unprotected steel elements, based on industry criteria (Roberge, 2008). Soluble chloride levels are below thresholds typically associated with aggressive corrosion of steel reinforcement but may still contribute to long-term degradation. All metallic components in direct contact with native soils should be designed for high corrosion resistance, and the use of non-metallic utility materials is recommended where feasible. Future imported fill should also be tested for corrosivity prior to use.

Soluble sulfate concentrations in the tested native soils were 510 ppm Soluble sulfate concentration of 510 ppm corresponds to ACI exposure class S1, indicating moderate sulfate exposure. Concrete in contact with native soils should conform to ACI 201.2R-16 provisions for this exposure class.

Future imported fill material is recommended to have corrosion testing performed on the soils to determine their potential for corrosion towards concrete and untreated steel.

3.6 Piping and Erosion

Surficial soils contain high fines content and may be susceptible to localized erosion during storm events. Piping risk is considered low, but proper surface water management and erosion control measures should be implemented during and after construction.

3.7 Shallow Bedrock

Bedrock was encountered 11 feet below existing site grade in the borings advanced. The bedrock material consisted of Mancos Shale in a highly to moderately weathered state. The bedrock is not anticipated to impact proposed improvements.

3.8 Seismic

The project site may be subject to moderate ground shaking during its design life due to regional seismicity. This hazard is addressed through structural design in accordance with the applicable edition of the International Building

Code (IBC). Site-specific seismic design parameters are provided in Section 4 – Geotechnical Recommendations.

The potential for surface fault rupture at the site is considered low. A review of the USGS Quaternary Fault and

Fold Database and the Utah Geological Hazards Portal indicates no mapped active faults within or immediately adjacent to the project boundary. No evidence of faulting was observed during the field investigation.

The potential for liquefaction and its secondary effects is also considered low. Liquefaction typically occurs in saturated, loose to medium dense sands and non-plastic silts during seismic shaking. The absence of shallow groundwater and the observed soil types suggest that the site is not susceptible to liquefaction-induced settlement, lateral spreading, or flow failure.

4 GEOTECHNICAL DESIGN RECOMMENDATIONS

The following geotechnical design recommendations have been developed based on the results of the field studies, laboratory testing, review of publicly available information, knowledge of the proposed structures, and experience.

These recommendations have been revised from the September 8, 2025, report to address updated structural loads up to 203 kips provided by Jones & DeMille Engineering and additional borings advanced on November 13, 2025.

The performance of the planned structures and infrastructure is dependent on conformance with the following recommendations. If changes are made to the Project, Moab Geotechnical Group should be contacted immediately to determine the validity of the following recommendations.

4.1 Seismic Design Parameters

The site is located within a seismically active area. In general accordance with IBC 2021 and ASCE 7-16, seismic design parameters for the structure have been developed using online Seismic Design Map Tool by the American

Society of Civil Engineers ASCE 7 Hazard Tool (ASCE, 2025). Following Section 11.4.3 of ASCE 7-16, site Class

D was selected for the Project. This assumption is appropriate provided the structural period of the structure is less than 0.5 seconds. Exhibit 4-1 provides a summary of the Seismic Design Parameters for use in the design of the structures.

Exhibit 4-1 Seismic Design Parameters

Period (seconds) Spectral Acceleration (g)

Site Modified Peak Ground Acceleration, PGAM 0.392

MCER Spectral Response Acceleration at Short Periods, SMS (g) 0.769

MCER Spectral Response Acceleration at 1-second Period, SM1 (g) 0.366

Design Spectral Response Acceleration at Short Period, SDS (g) 0.513

Design Spectral Response Acceleration at 1-second Period, SD1 (g) 0.244

Notes: 1) Based on assumed site location of Latitude: 39.086379° & Longitude: -111.130101

2) Based on Risk Category II

4.2 Lateral Earth Pressures

Lateral earth pressures will impart loads onto structures retaining earth loads. Exhibit 4-2 provides a summary of the lateral earth pressures for use in the design of walls, buried structures and other elements of the project. Active earth pressures are the earth pressures to be used for conditions where movements greater than 0.003H (H is the height of the wall in feet) are allowed for the structure. At rest pressures should otherwise be used as the earth pressures in the design of structures.

Passive earth pressures are to be used to resist the lateral earth pressures. Passive earth pressures should be ignored in the upper 24 inches of the ground surface due to the potential for frost to impact these soils. Passive earth pressures can be assumed to increase linearly in the frost susceptible zone. Exhibit 4-2 provides a summary for both native and imported structural fill soils.

Exhibit 4-2 Summary of Lateral Earth Pressures

Notes: psf – pounds per square foot, ft – feet

1. The static passive resistance can be increased by 1/3 to address other extreme events due to wind or snow loading.

2. The seismic earth pressures were calculated using the Mononobe Okabe methodology (Mononobe, 1929) (Okabe, 1926).

3. The seismic active and at rest earth pressure coefficients should be added to their respective static term.

4. The seismic passive earth pressure coefficient is the discounted static term and does not require any further factoring.

5. Based on Imported Structural Fill in accordance with Section 5.3.1.

4.3 Foundations

This section provides recommendations based on findings from the subsurface exploration, laboratory testing, and engineering analyses. Based on the proposed structure and encountered subsurface conditions, the building may be supported using either shallow foundation systems (as detailed in 4.3.1) or deep foundations (caissons) (as detailed in 4.3.4), depending on final structural loads and site constraints. If the planned structures cannot be supported using the recommendations provided herein, additional recommendations can be developed upon request by the Owner and Design Team.

4.3.1 Footings

A shallow foundation system is suitable for supporting the planned structure, provided the foundation subgrade is prepared according to the conditions outlined below. Footings may be designed for an allowable net bearing pressure of 3,250 psf.

Based on supplemental findings, the required subgrade preparation is contingent on the soil type encountered at the footing bearing elevation (approximately 36 inches below finished grade). The Geotechnical Engineer or their representative must observe and verify the subgrade materials in all footing excavations to confirm the appropriate preparation procedure.

For planning and bidding purposes, it should be assumed that approximately 50% of the footings will encounter granular soils (Condition B) at the bearing elevation, with the remaining 50% encountering fine-grained soils

(Condition A).

The following conditions shall be met:

• Subgrade Verification: All footing excavations must be observed by the Geotechnical Engineer to determine if the bearing subgrade consists of fine-grained or granular soils.

Standard Seismic2

Earth Pressure

Coefficient

Earth Pressure

(psf/ft)

Earth Pressure

Coefficient

Earth Pressure

(psf/ft)

Soil Type Active

At

Rest Passive1 Active

At

Rest Passive1 Active3

At

Rest3 Passive4 Active3

At

Rest3 Passive4

Native

Soil

0.33 0.55 2.7 42 66 300 0.09 0.16 2.5 9 19 270

Imported

Structural

Fill5

0.25 0.44 3.5 35 60 420 0.09 0.16 3.3 9 19 400

Condition A: Fine-Grained Soils Encountered at Subgrade Where native fine-grained soils (materials with 50% or more fines) are encountered at the footing bearing elevation:

• Over-Excavation: The area beneath the footing shall be over-excavated to a minimum depth of 60 inches

(5.0 feet) below final grade (i.e., 24 inches below the footing base).

• Subgrade Preparation: The bottom of the resulting excavation (at 60 inches) shall be scarified to a depth of

12 inches, moisture-conditioned, and compacted to at least 95% of the modified Proctor maximum dry density (ASTM D1557).

• Structural Fill: Place 24 inches (2.0 feet) of 'Structural Fill' (in accordance with Section 5.3.1), compacted in lifts, to bring the subgrade up to the footing bearing elevation.

Condition B: Granular Soils Encountered at Subgrade Where native granular soils (materials with less than

50% fines) are encountered at the footing bearing elevation:

• Over-Excavation: Over-excavation is not required.

• Subgrade Preparation: The exposed native subgrade at the footing bearing elevation (36 inches) shall be scarified to a depth of 12 inches, moisture-conditioned, and compacted to at least 95% of the modified

Proctor maximum dry density (ASTM D1557).

General Footing Requirements (All Conditions):

• Observation: All prepared subgrades (whether at the 36-inch elevation or the 60-inch elevation) must be observed by the Geotechnical Engineer to be firm and unyielding prior to fill or concrete placement.

• Embedment: Footings should be embedded at least 36 inches below finished grade for frost protection.

Load Increase: The allowable bearing pressure may be increased by one-third for temporary loads (e.g., wind or seismic).Total settlement is expected to be less than 1 inch, with differential settlement up to 1 inch over 50 feet.

4.3.2 Interior Slab on Grade

Slab-on-grade areas should be underlain by a minimum of six inches of compacted gravel, placed over a subgrade prepared per Section 5.2 and verified to be firm and unyielding. Slabs may be designed using a modulus of subgrade reaction (k-value) of 4 to 9 psi/in. For critical slab performance, project-specific testing (e.g., plate load tests) may be performed.

Slabs should be constructed in accordance with ACI 302.1R-15, and include:

• Isolation joints between slabs and bearing walls/columns.

• Welded wire fabric (WWF) or rebar for crack control.

• Control joints throughout the slab.

• Flexible couplings at mechanical connections and positive breaks at plumbing penetrations.

4.3.3 Sliding Resistance

For footings and slabs on grade founded on properly prepared imported fill, a coefficient of friction of 0.34 may be used. These values can be increased by 1/3 for temporary loading conditions. Additional lateral support can be accommodated by utilizing the passive lateral earth pressures provided in Section 4.2. Note that the local frost depth should be considered when utilizing lateral earth pressures.

4.3.4 Deep Foundations – Caissons

Where shallow foundations are not feasible due to structural loads or site constraints, drilled piers (caissons) may be used. Based on subsurface conditions encountered during this investigation, caissons may be designed using a skin friction value of 300 psf per foot of embedded column length.

Preliminary calculations for the 203k combined loads indicate that caisson lengths founded only on skin friction will significantly exceed 10 feet. As our subsurface exploration was limited to this depth, a supplemental investigation using a drill rig is mandatory to evaluate deeper subsurface conditions, confirm soil and rock properties, and identify any end-bearing stratum before this alternative can be finalized.

Design considerations include:

• Minimum embedment to achieve required axial capacity.

• Construction methods to avoid disturbance of native soils and groundwater intrusion.

• Group effects and spacing requirements for multiple piers.

• Lateral pile parameters (e.g., modulus of subgrade reaction, p-y curves) can be provided upon request to support structural design of laterally loaded deep foundations.

4.4 Vapor Reduction

Water from beneath the slab will migrate through the slab into the building over time. This water vapor can be reduced but not stopped. Vapor transmission can negatively affect floor coverings and lead to increased moisture within a building. We recommend the following to reduce, but not stop, water vapor transmission upward through the slab-on-grade.

• Install a vapor retarder membrane directly beneath the slab. Seal the vapor retarder at all seams and pipe penetrations. Vapor retarders should conform to class A vapor retarder per ASTM E 1745-11 “Standard

Specification for Plastic Water Vapor Retarders used in Contact with Soil or Granular Fill under Concrete

Slabs”.

• Place 4-inches of clean, crushed rock below the vapor retarder membrane. Crushed rock should have 100 percent passing the ¾-inch sieve and less than 5 percent passing the No. 4 Sieve.

• Concrete should have a concrete water-cement ratio of no more than 0.50.

• Provide inspection and testing during concrete placement to check that the proper concrete and water-cement ratio are used.

• Moist cure slabs for a minimum of 3 days or use the equivalent curing specified by the Structural Engineer.

4.5 Drainage and Landscaping

Proper site drainage is critical given the dry climate and the presence of collapsible and erodible soils, which are highly sensitive to moisture infiltration. Excess moisture in foundation or slab subgrade soils can lead to volume loss and differential settlement. Therefore, stormwater runoff and irrigation must be carefully managed to support the long-term performance of foundations and other site improvements.

The following is recommended and should be incorporated into the project’s grading and drainage design:

• Water should not be allowed to pond near foundations, slabs-on-grade, pavements, or other improvements.

Finished soil grades should slope away from structures at a minimum of five percent for the first 10 feet, consistent with 2021 IBC Section 1804.4. Flatwork can be designed to flow at two percent away from the structure.

• Roof downspouts and drainage from impervious surfaces should be routed away from foundation walls.

Where possible, roof drains should be directly connected to the site’s stormwater management system. If direct connection is not feasible, discharge should occur a minimum of 10 feet from any foundation element and be directed into properly graded swales or collection areas.

• Landscaping immediately adjacent to buildings should be limited to drought-tolerant vegetation or dry-scape features that do not require frequent irrigation.

• Stormwater should be prevented from sheet flowing off roadways and eroding or saturating supporting subgrades. Instead, runoff should be captured and conveyed using a curb and gutter system integrated into the broader stormwater management plan.

Final grading and drainage design should be performed by a licensed Civil Engineer and should incorporate these geotechnical considerations to minimize the potential for moisture-related soil movement and associated structural distress.

4.6 Pavement

Pavement improvements on the project should be made in conformance with the following recommendations.

Exhibit 4-3 Recommended Pavement Sections

Application Surface Course Base Course

Heavy-Duty Rigid Pavement

(trash truck access and dumpster pads)

6-inch Portland Cement Concrete

(Reinforced per ACI 330R) 4-inch Aggregate Base Course

Heavy-Duty Flexible Pavement 3.5-inch Hot Mix Asphalt 4-inch Aggregate Base Course

Light-Duty Flexible Pavement 2.5-inch Hot Mix Asphalt 4-inch Aggregate Base Course

Light-Duty Rigid Pavement 4-inch Portland Cement Concrete 4-inch Aggregate Base Course

Subgrade should be scarified to a depth of at least 12 inches, moisture conditioned, and compacted prior to base placement. Aggregate base should conform to UDOT Standard Specification Section 02721 (Untreated Base

Course), or engineer-approved equivalent. All base and subgrade materials should be compacted to a minimum of 95% relative compaction per ASTM D1557, Modified. Concrete should achieve a minimum compressive strength of 4,000 psi in 28 days. Hot Mix Asphalt (HMA) should be designed and placed in accordance with FP-

14 Section 401 or AASHTO M 320 (Superpave), and must meet applicable standards for asphalt content, gradation, and compaction.

Pavement sections designed for post-construction traffic may not withstand heavy construction vehicles.

Consider temporary construction access routes or thicker interim sections if early use is expected. Regular maintenance such as crack sealing, seal coating (for asphalt), and joint resealing (for concrete) is recommended to extend pavement life.

4.7 Concrete Flatwork

Concrete flatwork, including exterior walkways, driveways, patios, and steps, should be designed for anticipated use and loading conditions, and constructed in accordance with recognized standards such as ACI 330R Guide for the Design and Construction of Concrete Parking Lots (ACI, 2008) and applicable municipal specifications.

The subgrade should be prepared as described in Section 5.2 and observed to be firm and unyielding prior to fill placement.

Slab reinforcement should be designed by the project structural engineer and should include, at a minimum, welded wire fabric (WWF) or rebar to help control cracking. Control and isolation joints should be incorporated in accordance with ACI 330R, with final layout based on slab geometry, thickness, and anticipated loading.

Positive drainage away from all flatwork should be maintained to prevent ponding and moisture-related subgrade degradation. Additional drainage guidance is provided in Section 4.5.

5 CONSTRUCTION CONSIDERATIONS

The success of the project and the considerations provided in this report have been prepared assuming the following construction considerations are incorporated into the development of the Project. Where the considerations cannot be followed, or alternative construction methods are to be employed to construct the Project, MGG should be notified.

5.1 Site Preparation

Prior to site development, undocumented fill, weeds and organic material should be cleaned to a firm, undisturbed soil surface determined by a Geotechnical Engineer. Existing test pits on the property, excavated prior to our site visit, should be prepared in the same manner.

5.2 Subgrade Preparation

Subgrade is defined as the lowest depth to which soil is excavated prior to fill or foundation placement. Following excavation, subgrade preparation should consist of scarifying the upper 12 inches, moisture conditioning, and compacting the material in place. Scarification can generally be performed using an excavator bucket with teeth.

Subgrade soils should be compacted to at least 95 percent of the modified Proctor maximum dry density (ASTM

D1557) and within one percentage point of the optimum moisture content.

A Geotechnical Engineer should observe and test all subgrade areas prior to fill placement to verify that the subgrade is firm, unyielding, and consistent with the conditions encountered during the subsurface investigation. Where soft or loose zones are identified, additional excavation or installation of a geotextile reinforcing material may be required. Overexcavation should extend at least one foot laterally from any areas identified as being soft or loose.

If the overexcavation required becomes too large, the geotextile reinforcing material can help limit the required overexcavation volume. A Mirafi HP270 or an MGG approved equivalent is recommended to reinforce soft or loose material.

5.3 Fill Placement

Fill placement is anticipated to be required to achieve the proposed site grades and to balance earthwork for the project. Onsite soils are considered suitable for reuse, provided they meet the criteria outlined in the following subsections. All fill materials intended to support structures, pavements, or flatwork should be compacted to at least

95 percent of the modified Proctor maximum dry density (ASTM D1557) and within one percentage point of the optimum moisture content.

The height of the loose lifts to be used as the fill material is placed is dependent on the machinery used to compact the soils. Where hand-held jumping jacks or walk-behind compactors are used, we recommend that loose lifts not exceed 8 inches. For excavators outfitted with a wheel compactor, 10-inch loose lifts should be used. For large sheep foot or drum rollers, 12-inch loose lifts can be used. Larger lift thicknesses can be used provided that the contractor can demonstrate adequate compaction through the compacted lift. Fill material should be free of frozen material or free water. Where free water is present, we recommend the material be blended with dry material to reach the required moisture content. Frozen soils should be set aside and not utilized until they are unfrozen.

5.3.1 Structural Fill

Structural Fill shall consist of imported granular material conforming to AASHTO Classification A-1-a, which is approved for use. Any proposed alternative fill material must be approved by Moab Geotechnical Group (MGG) prior to use and shall, at a minimum, consist of a 3-inch minus material with no more than 15 percent fines. The

Atterberg Limit (ASTM 4318) of the material should result in a Plasticity Index less than 8. The material should not be open-graded or well-rounded and must be free of organic and deleterious materials. It is recommended that

MGG be provided with test results and a sample of any proposed fill source, including A-1-a, to verify compliance prior to import.

5.4 Utilities

Utilities should be installed in accordance with the requirements of the local authority having jurisdiction and applicable industry standards. In the absence of municipal guidance, trench excavation, bedding, and backfill should follow the Utah APWA Standards. Trench backfill should be placed in lifts and compacted in accordance with

Section 5.3.

5.5 Excavations

Trench and excavation safety is the requirement of the contractor installing the utilities and performing excavations.

We recommend the contractor be familiar with the necessary OSHA 1926 standards and have a person onsite who can perform the necessary duties of the Competent Person as defined by OSHA. Soil conditions can vary from those explored as part of this investigation and therefore soil types, in accordance with OSHA, should be assessed by the onsite Competent Person.

6 ADDITIONAL SERVICES

Moab Geotechnical Group (MGG) strongly encourages our continued involvement with the project leading up to and during construction. The additional services we can provide will help ensure the recommendations and construction considerations are followed and that adverse conditions encountered during construction are properly addressed.

6.1 Project Progression

As the design of the project advances, we recommend we be informed of changes that differ from those assumed or detailed in this report. Successful performance of the future structures and infrastructure are dependent on the findings used to prepare this report. This report can be revised from its current state with subsequent changes and evolution of the project.

6.2 Plan and Specification Review

It is recommended that MGG review the final plans and specifications for the project. The adherence to the recommendations and construction considerations will help the long-term performance of the proposed structures and associated improvements. The review can also check if any changes in the nature, design or location of the proposed improvements and provide opportunity to prepare a written response with updated recommendations, if needed.

6.3 Testing and Observation Services

Testing and observation services can be performed by moisture / density testing and by onsite observation and testing. These services should be considered in the future construction costs of the project. All earthwork operations should be performed under the fulltime to temporary observation of our representative to check that the site properly prepared, the selected fill materials are satisfactory, and that placement and compaction of the fills have been performed in accordance with our recommendations and project specifications. Site observations also aid in addressing potentially problematic soils that were not found during the site characterization and field investigation phase.

7 LIMITATIONS

This report is issued with the understanding that it is the responsibility of the owner to transmit the information and recommendations of this report to developers, contractors, buyers, architects, engineers, and designers for the project so that the necessary states can be taken by the contractors and subcontractors to carry out such recommendations in the field.

Moab Geotechnical Group (MGG) strived to perform our professional services in accordance with generally accepted geotechnical engineering principles and practices currently employed in the area; no warranty is expressed or implied. There are risks of earth movement and property damages inherent in land development. MGG is unable to eliminate all risks or provide insurance; therefore, MGG is unable to guarantee or warrant the results of the work.

This report is based upon field and other conditions discovered at the time of preparation of our work. This document must not be subject to unauthorized reuse, that is, reuse without our written authorization. Such authorization is essential because it requires us to evaluate the document’s applicability given new circumstances, not the least of which is passage of time.

Actual field or other conditions will necessitate clarifications, adjustments, modifications, to other changes to our work. Therefore, we must be engaged to prepare the necessary clarifications, adjustment modifications, or other changes before construction activities commence or further activity proceeds.

REFERENCES

American Concrete Institute [ACI], 2019, Building Code Requirements for Structural Concrete, ACI 318

American Concrete Institute [ACI], 2016, Guide to Durable Concrete, ACI 201.2R-16

American National Standard [ANSI]/ AARST Consortium on National Radon Standards, 2023, Soil Gas Control

Systems in New Construction of Multifamily, School, Commercial and Mixed-Use Buildings

American Society of Civil Engineers [ASCE], 2025, ASCE 7 Hazard Tool, ASCE 7 Hazard Tool, accessed on July

31, 2025.

American Society of Civil Engineers [ASCE], 2017, Minimum Design Loads and Associated Criteria for Buildings and Other Structures (ASCE 7-16)

ASTM International, 2023, Standard Test Method for Use of the Dynamic Cone Penetrometer in Shallow Pavement

Applications (ASTM D6951/D6951M-18, reapproved 2023): ASTM International, West Conshohocken, PA.

Hellmut H. Doelling, 1972, Coal and geology map, Castle Dale SW [Ferron] quadrangle. MO-3-F. UGMS. 1:42,000 scale.

International Code Council, 2021, International Building Code. Falls Church, Va. :International Code Council

Jones & DeMille Engineering, 2025, Structural Column Loads, Ferron Fairgrounds Event Center, project correspondence, October 31.

Lockwood, D., et al, 1992, Analysis and Classification of DCP Survey Data, Technology & Information

Management Programme, CSIR Transporteck, Pretoria, South Africa

Mononobe, N. and H. Matsuo, 1929, On the Determination of earth Pressures During Earthquakes, Proceedings of the World Engineering Congress

Nationwide Environmental Title Research, LLC (NETR), 2025, Historic aerial imagery viewer:

HistoricAerials.com, accessed September 4, 2025, at https://www.historicaerials.com.

Okabe, S., 1926, General Theory of Earth Pressure, Journal of Japan Society of Civil Engineering Vol. 12, No. 1

Packard, R.G., 1973, Design of Concrete Airport Pavement: Portland Cement Association Engineering Bulletin, Portland Cement Association, Skokie, IL, reprinted 1995.

Roberge, Pierre R., 2000, Handbook of Corrosion Engineering, McGraw-Hill

United States Geological Survey [USGS], 2024, 1/3 arc-second Digital Elevation Model (DEM), N37W111: The

National Map, U.S. Geological Survey, published October 31, 2024, accessed August 21, 2025, from https://www.nationalmap.gov.

United States Geological Survey [USGS], 2024, U.S. Landslide Inventory and Susceptibility Map, U.S. Landslide

Inventory and Susceptibility Map | U.S. Geological Survey, accessed on August 15, 2025.

United States Geological Survey [USGS], 2024, Quaternary Fault and Fold Database of the United States, Faults

| U.S. Geological Survey, accessed on August 15, 2025.

https://asce7hazardtool.online/ https://www.historicaerials.com/ https://www.nationalmap.gov/ https://www.usgs.gov/tools/us-landslide-inventory-and-susceptibility-map https://www.usgs.gov/tools/us-landslide-inventory-and-susceptibility-map https://www.usgs.gov/programs/earthquake-hazards/faults https://www.usgs.gov/programs/earthquake-hazards/faults

FERRON FAIRGROUND EVENT CENTER 2025-068

APPENDIX A – TEST PIT AND BORING LOGS

MOISTURE CONTENT

FIELD TESTCONSISTENCEY

Absence of moisture, dusty, dry to the touchDry (D)

Damp but no visible waterMoist (M)

Visible free water, usually soil is below water table Wet (W)

RELATIVE CONSISTENCY - COHESIVE SOIL

POCKET

PENETROMETER, tsf

UNCONFINED

SHEAR STRAIN

TORVANE, tsf

SHEAR

STRAIN

SPT-N VALUE

(# BLOWS/FT)

DESCRIPTION

<0.25< 0.13< 2Very Soft (VS)

0.25 to 0.50.13 to 0.252 to 4Soft (S)

0.5 to 10.25 to 0.54 to 8Medium Stiff (MSt)

1 to 20.5 to 18 to 15Stiff (St)

2 to 41 to 215 to 30Very Stiff (VSt)

>4>2Over 30Hard (H)

RELATIVE DENSITY - COHESIONLESS SOIL

SPT-N VALUE

(# BLOWS/FT)

DESCRIPTION

< 4Very Loose (VL)

4 to 10Loose (L)

10 to 30Medium Dense (MD)

30 to 50Dense (D)

> 50Very Dense (VD)

GRAIN SIZE

GRAIN SIZE / SIEVE NO.DESCRIPTION

>12"Boulders (Bo)

3 to 12"Cobbles (Co)

3/4 to 3"coarse (c) Gravel (Gr)

No. 4 to 3/4"fine (f)

No. 10 to No. 4coarse (c)

Sand (Sa) No. 40 to No.10medium (m)

No. 200 to No. 40fine (f)

< No. 200Fines (Fi)

PERCENTAGE TERMS

PERCENT RANGEADJECTIVE

<5%Trace

5 to 10%Few

15 to 25%Little

30 to 45%Some

50 to 100%Mostly

Gravel , sand and silt estimated by mass.

Organics cobbles and boulders estimated by volume.

STRUCTURE

CRITIERIADESCRIPTION

Alternating layers of varying material or color with layers at least 1/4-inch thick; note thickness; singular:

Bed

Interbedded (int)

Alternating layers of varying material or color with layers less than 1/4-inch thick; note thickness;

singular: Lamination

Laminated (lam)

Breaks along definite planes of fracture with little resistance to fracturing

Fissured

(fis)

Fracture planes appear polished or glossy, sometimes striated Slickensided (slk)

Cohesive soil that can be broken down into small angular lumps which resist further breakdown

Blocky

(blky)

Inclusion of small packets of different soils such as small lenses of sand scattered through a mass of clay;

note thickness

Lensed

(lnsd)

Same color and appearance throughoutHomogeneous (hom)

Angularity Figure Source: M.C Powers, 1953, A New Scale of Particle Roundness for Sedimentary Particles, p.118

FIG. A-01

SOIL REFERENCE

STANDARD

ANGULARITY

FERRON FAIRGROUND

EVENT CENTER

FERRON, UT

Project No.: 2025-068

November 2025

CEMENTATION

FIELD TESTDESCRIPTION

Crumbles of breaks with handling or slight finger pressure Weakly

Crumbles or breaks with considerable finger pressure Moderately

Will not crumble or break with finger pressureStrongly

REACTION WITH HCL

FIELD TESTDESCRIPTION

No visible reactionNone

Some reaction, with bubbles forming slowlyWeak

Strong reaction, with bubbles forming immediatelyStrong

ROCK REFERENCE

STANDARD

Project No.: 2025-068

November 2025

DISCONTINUITY TERMS

FRACTURE- collective term for any natural break excluding shears, shear zones, and faults

JOINT (JT) - Planar break with little or no displacement

FOLIATION JOINT (FJ) or BEDDING JOINT (BJ) - Joint along foliation or bedding

INCIPIENT JOINT (IJ) or INCIPIENT FRACTURE (IF) - Joint or fracture not evident until wetted and dried;

breaks along existing surface

RANDOM FRACTURE (RF) - Natural, very irregular fracture that does not…