5-4-DA27008-26190550 Approved Geotechnical Report.pdf

GEOTECHNICAL INVESTIGATION

PROPOSED EVIDENCE BUILDING

4451 SOUTH 2700 WEST

TAYLORSVILLE, UTAH

PREPARED FOR:

DFCM - STATE OF UTAH

4315 SOUTH 2700 WEST, 3 FLOORRD

TAYLORSVILLE, UTAH 84129-2128

ATTENTION: ROB ROBINSON

PROJECT NO. 1250534 SEPTEMBER 30, 2025

REVISED OCTOBER 1, 2025

AGC.,CAGC.,C

Applied Applied GeoTechGeoTech

600600 WWesest t SSandy andy Parkway Parkway • • SSandy, andy, Utah Utah 84070 84070 • • (801) (801) 566-6399 566-6399 • • www.agecinc.comwww.agecinc.com

TABLE OF CONTENTS

EXECUTIVE SUMMARY.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1

SCOPE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2

SITE CONDITIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2

FIELD STUDY.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 3

GEOPHYSICAL MEASUREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 3

PERCOLATION TESTING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4

SUBSURFACE CONDITIONS.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 5

SUBSURFACE WATER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6

PROPOSED CONSTRUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 6

RECOMMENDATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7 A. Site Grading. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 7 B. Foundations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 9 C. Concrete Slab-on-Grade. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 11 D. Lateral Earth Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 11 E. Seismicity, Faulting and Liquefaction. . . . . . . . . . . . . . . . . . . . . Page 13 F. Water Soluble Sulfates.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 14 G. Pavement.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 14 H. Continuing Services. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 16

LIMITATIONS.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 17

REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 18

FIGURES

EXPLORATORY BORING, PERCOLATION TEST, TRENCH

AND GEOPHYSICAL MEASUREMENT LOCATIONS FIGURE 1

EXPLORATORY BORING LOGS FIGURE 2

EXPLORATORY BORING LEGEND AND NOTES FIGURE 3

CONSOLIDATION TEST RESULTS FIGURES 4-5

SUMMARY OF LABORATORY TEST RESULTS TABLE I

APPENDIX A

SHEAR WAVE VELOCITY RESULTS

APPENDIX B

ASCE HAZARDS REPORT

EXECUTIVE SUMMARY

1. The soils encountered in the borings consist of approximately 4 inches of topsoil overlying lean clay. Gravel was encountered below the clay in Boring B-1 at a depth of approximately 8½ feet and extends the full depth of the boring, approximately 20½ feet. Approximately 1½ feet of silty sand was encountered in Boring B-2 at a depth of approximately 9 feet underlain by gravel extending to a depth of approximately 17 feet. Lean Clay was encountered below the gravel and extended the full depth of the boring, approximately 20½ feet. Approximately 1 foot of silty sand was encountered in Boring B-3 at a depth of approximately 9 feet underlain by gravel extending to a depth of approximately 19 feet. The gravel is underlain by layers of silt, clay, sand and gravel to the full depth of boring, approximately 51 feet.

2. Subsurface water was encountered at a depth of approximately 36 feet in Boring B-3 when measured September 5, 2025. The other two borings did not extend deep enough to encounter water. Fluctuations in water levels should be expected over time.

3. The building may be supported on spread footings bearing on the undisturbed natural soil or on structural fill extending down to the natural undisturbed soil and may be designed for a net allowable bearing pressure of 1,500 pounds per square foot. Footings bearing on at least 2 and 4 feet of structural fill may be designed for net allowable bearing pressures of 2,500 and 3,500 pounds per square foot, respectively.

4. The upper soil consists predominantly of clay and can cause access difficulties for construction equipment when the clay is very moist to wet.

Placement of 1 to 2 feet of granular fill will improve site access conditions when the subgrade consists of very moist to wet clay.

5. The site is located in an area mapped to have a moderate liquefaction potential. Based on the subsurface conditions encountered at the site, liquefaction is not considered to be a significant hazard.

6. Geotechnical information relating to foundations, subgrade preparation, materials and pavement is included in the report.

APPLIED GEOTECHNICAL ENGINEERING CONSULTANTS, INC. 1250534

SCOPE

This report presents the results of a geotechnical investigation for the proposed evidence building to be constructed at 4451 South 2700 West in Taylorsville, Utah. The report presents the subsurface conditions encountered, laboratory test results and recommendations for foundations and pavement. The study was conducted in general accordance with our proposal dated July 21, 2025.

Field exploration was conducted to obtain information on the subsurface conditions at the site. Samples obtained from the study were tested in the laboratory to determine physical and engineering characteristics of the on-site soil. Information obtained from the field and laboratory investigations was used to define conditions at the site and to develop recommendations for the proposed foundations and pavement.

This report has been prepared to summarize the data obtained during the study and to present our conclusions and recommendations based on the proposed construction and the subsurface conditions encountered. Design parameters and a discussion of geotechnical engineering considerations relating to construction are included in the report.

SITE CONDITIONS

At the time of our field study, the site consisted of a grass covered field.

The ground surface at the site is relatively flat with a gentle slope down to the northeast.

Vegetation at the site consists of grass. There are some trees along the western edge of the property.

There are sheds and paved storage areas to the east, a parking lot to the west, a State building to the north and a continuation of the field to the south.

FIELD STUDY

Three borings were drilled on August 26, 2025 at the approximate locations indicated on

Figure 1 using 8-inch-diameter hollow-stem auger. The borings were logged and soil samples obtained by a geologist from AGEC. A trench was excavated along the southern side of the proposed building on August 28, 2025 using a rubber-tired backhoe to determine if there is evidence of a fault extending through the proposed building area. The trench was logged by geologists from AGEC. Logs of the subsurface conditions encountered in the borings are graphically shown on Figure 2 with legend and notes on Figure 3. The log of the trench is presented in a separate report.

The trench was backfilled without compactive effort and not placed uniformly or tested for compaction. The backfill in the trench should be removed and be properly compacted where it will support proposed buildings, slabs, pavements and other settlement-sensitive features planned for the site.

GEOPHYSICAL MEASUREMENTS

Geophysical methods, consisting of multi-channel analysis of surface waves (MASW) and micro-tremor array measurements (MAM) were performed at the site on September 18, 2025. The approximate locations of the arrays are shown on Figure 1.

MASW

The MASW was performed using a 150-foot array of twenty-four 4.5-Hz vertical geophones, placed at 6½-foot spacings. The geophones were used to record wavefields with strong Rayleigh wave content that were actively generated by striking vertically downward with a 16-pound sledgehammer on a steel plate. The sledgehammer was used at six distinct “shot” locations that were offset 16, 32 and

48 feet relative to the geophones at either end of the array. Five distinct sledgehammer blows were recorded at each “shot” location to allow for signal stacking.

MAM

The MAM was performed using an L-shaped array. The legs of the array were

197 and 180 feet long, respectively, and comprised of twenty-four 4.5-Hz vertical geophones, placed at 16-foot spacings. Ambient vibrations were recorded for approximately 1 hour, with record lengths of 1 minute each.

The collected data was processed into dispersion data using the swprocess software

(Vantassel and Cox, 2024). The MAM and MASW data were trimmed together and an experimental target for inversion selected using swprepost (Vantassel and Cox, 2022).

Results of the trimmed and target data are shown in the Appendix A. The inversion target was converted to a suite of possible shear wave velocity profile models using Geopsy

Version 3.4.2 (Wathelet, 2025).

The median velocity profile of the best 100 models is shown in the Appendix A. We

S,30calculate an average shear wave velocity value for the top approximately 100 feet (V ), of 890 ± 20 feet per second, in general accordance with ASCE 7-16 § 20.4.1.

PERCOLATION TESTING

A percolation test was performed in Boring P-1 indicated on Figure 1 at a depth of approximately 8 feet below grade. The boring was filled with water the day of drilling and the percolation test performed on August 27, 2025. Approximately ½ foot of water was placed in the boring and the drop in water level measured after 60 minutes. The test was repeated until a consistent drop in water level was measured. A percolation rate of 15 minutes per inch was obtained.

SUBSURFACE CONDITIONS

The soils encountered in the borings consist of approximately 4 inches of topsoil overlying lean clay. Gravel was encountered below the clay in Boring B-1 at a depth of approximately

8½ feet and extends the full depth of the boring, approximately 20½ feet. Approximately

1½ feet of silty sand was encountered in Boring B-2 at a depth of approximately 9 feet underlain by gravel extending to a depth of approximately 17 feet. Lean Clay was encountered below the gravel and extended the full depth of the boring, approximately 20½ feet. Approximately 1 foot of silty sand was encountered in Boring B-3 at a depth of approximately 9 feet underlain by gravel extending to a depth of approximately 19 feet. The gravel is underlain by layers of silt, clay, sand and gravel to the full depth of boring, approximately 51 feet.

A description of the soils encountered in the borings follows:

Topsoil - The topsoil consists of lean clay. It is moist, dark brown and contains organics.

Lean Clay - The clay contains thin silt and sand layers. It is medium to very stiff, moist to wet and brown to gray.

Laboratory tests performed on samples of the clay indicate it has natural moisture contents ranging from 14 to 31 percent and natural dry densities of 87 to 96 pounds per cubic foot. An unconfined compressive strength of 1,850 pounds per square foot was measured for a sample of the clay. Results of consolidation tests on the clay indicate the clay will compress a small to moderate amount with the addition of light to moderate loads. Results of the consolidation tests are presented on Figures 4 and 5.

Silty Sand - The sand contains occasional gravels. It is medium dense, moist to wet and brown.

Laboratory tests performed on a sample of the sand indicate it has a natural moisture contents of 25 percent.

Poorly Graded Gravel with Silt and Sand - The gravel has clayey zones. It is medium to very dense, moist to wet and brown.

Laboratory tests performed on a sample of the gravel indicate it has a natural moisture content of 5 percent and a natural dry density of 109 pounds per cubic foot.

Results of the laboratory tests are summarized on Table I and are included on the logs of the borings.

SUBSURFACE WATER

Subsurface water was encountered at a depth of approximately 36 feet in Boring B-3 when measured September 5, 2025. The other two borings and the trench did not extend deep enough to encounter water. Fluctuations in water levels should be expected over time.

PROPOSED CONSTRUCTION

We understand that the property is being considered for a single-story structure with a slab-on-grade floor. The structural engineer indicates maximum column loads will be 240 kips and maximum wall loads will be 6.8 kips per foot.

Parking and drive areas will be constructed for the project. We have provided pavement recommendations considering areas of 50 cars and no truck traffic, and areas with truck traffic. We have assumed 50 cars and 10 delivery trucks per day, and two garbage trucks per week for truck areas.

If the proposed construction, building loads or traffic is significantly different from what is described above, we should be notified so that we can reevaluate the recommendations given.

RECOMMENDATIONS

Based on the subsurface conditions encountered, laboratory test results and our understanding of the proposed construction, the following recommendations are given:

A. Site Grading

1. Subgrade Preparation

The topsoil, organics, unsuitable fill, debris and other deleterious materials should be removed from below the proposed building, slabs, pavement and other settlement-sensitive improvements.

The upper soil consists predominantly of clay and can cause access difficulties for construction equipment when the clay is very moist to wet.

Placement of 1 to 2 feet of granular fill will improve site access conditions when the subgrade consists of very moist to wet clay.

2. Excavation

We anticipate that excavation at the site can be accomplished with typical excavation equipment. Temporary excavations may be excavated at 1 horizontal to 1 vertical or flatter. Permanent cut and fill slopes may be constructed at 2 horizontal to 1 vertical or flatter.

3. Materials

Listed below are recommendations for imported structural fill.

Fill to Support Recommendations

Footings Non-expansive granular soil Passing No. 200 Sieve < 35% Liquid Limit < 30% Maximum size 4 inches

Floor Slab (Upper 4 inches)

Sand and/or Gravel Passing No. 200 Sieve < 5% Maximum size 2 inches

Slab Support Non-expansive granular soil Passing No. 200 Sieve < 50% Liquid Limit < 30% Maximum size 6 inches

Materials placed as fill to support the building should be non-expansive granular soil. The natural soil is not recommended for use as structural fill, but may be used as site grading fill, and as utility trench and wall backfill if the topsoil, organics and other deleterious materials are removed or it may be used in landscaping areas.

The soil may require moisture conditioning prior to use as fill depending on the soil moisture content at the time of construction. Drying of the soil may not be practical during cold or wet periods of the year.

4. Compaction

Compaction of materials placed at the site should equal or exceed the minimum densities as indicated below when compared to the maximum dry density as determined by ASTM D 1557.

Fill To Support Compaction Criteria

Foundations $ 95%

Concrete Slabs $ 90%

Pavement Base Course Fill placed below Base Course

$ 95% $ 90%

Landscaping $ 85%

Retaining Wall Backfill 85 - 90%

To facilitate the compaction process, fill should be compacted at a moisture content within 2 percent of the optimum moisture content.

The fill should be placed and compacted in thin enough lifts to allow for proper compaction. Fill placed for the project should be frequently tested for compaction.

5. Drainage

The ground surface surrounding the proposed building should be sloped away from the building in all directions. Roof downspouts and drains should discharge beyond the limits of backfill.

The collection and diversion of drainage away from the pavement surface is important to the satisfactory performance of the pavement section. Proper drainage should be provided.

B. Foundations

1. Bearing Material

With the proposed construction and the subsurface conditions encountered, the building may be supported on spread footings bearing on the undisturbed natural soil or on compacted structural fill extending down to the natural undisturbed soil. Structural fill should extend down to the undisturbed natural soil and out away from the edge of the footings at least a distance equal to the depth of fill beneath footings.

Topsoil, unsuitable fill, organics, debris and other deleterious materials should be removed from below footing areas.

2. Bearing Pressure

Spread footings bearing on the undisturbed natural soil or on compacted structural fill extending down to the undisturbed natural soil may be designed using a net allowable bearing pressure of 1,500 pounds per square foot.

Footings bearing on at least 2 and 4 feet of structural fill may be designed for net allowable bearing pressures of 2,500 and 3,500 pounds per square foot, respectively.

3. Settlement

We estimate that total and differential settlements will be less than 1 and ½ inch, respectively, for footings designed as indicated above.

4. Temporary Loading Conditions

The allowable bearing pressure may be increased by one-half for temporary loading conditions such as wind or seismic loads.

5. Frost Depth

Exterior footings and footings beneath unheated areas should be placed at least 30 inches below grade for frost protection.

6. Foundation Base

The base of foundation excavations should be cleared of loose or deleterious material prior to fill or concrete placement.

7. Construction Observation

A representative of the geotechnical engineer should observe footing excavations prior to structural fill or concrete placement.

C. Concrete Slab-on-Grade

1. Slab Support

Concrete slabs may be supported on the undisturbed natural soil or on compacted structural fill extending down to the undisturbed natural soil.

Topsoil, organics, unsuitable fill, debris and other deleterious materials should be removed from below proposed slab areas.

2. Underslab Sand and/or Gravel

A 4-inch layer of free-draining sand and/or gravel (less than 5 percent passing the No. 200 sieve) should be placed below floor slabs for ease of construction and to promote even curing of the slab concrete.

3. Vapor Barrier

A vapor barrier should be placed under the concrete floor if the floor will receive an impermeable floor covering. The barrier will reduce the amount of water vapor passing from below the slab to the floor covering.

D. Lateral Earth Pressure

1. Lateral Resistance for Footings

Lateral resistance for footings placed on the natural soil or on compacted structural fill is controlled by sliding resistance between the footing and the foundation soils. A friction value of 0.35 may be used in design for ultimate lateral resistance. A friction value of 0.45 may be used in design for ultimate lateral resistance where at least 2 feet of structural fill is placed below footings. The passive resistance of the soil adjacent footings may be added to the friction resistance.

2. Subgrade Walls and Retaining Structures

The following equivalent fluid weights are given for the design of subgrade walls and retaining structures. The active condition is where the wall moves away from the soil. The passive condition is where the wall moves into the soil and the at-rest condition is where the wall does not move. The values listed below assume a horizontal surface adjacent the wall.

Soil Type Active At-Rest Passive

Clay & Silt 50 pcf 65 pcf 250 pcf

Sand & Gravel 40 pcf 55 pcf 300 pcf

3. Seismic Conditions

Under seismic conditions, the equivalent fluid weight should be increased by

42 pcf for the active condition and 27 pcf for the at-rest condition. A decrease of 42 pcf is recommended for the passive condition. This assumes a peak ground acceleration of 0.70g which represents a 2 percent probability of exceedance in a 50-year period.

4. Safety Factors

The values recommended above assume mobilization of the soil to achieve the soil strength under active and passive conditions. Conventional safety factors used for structural analysis for such items as overturning and sliding resistance should be used in design.

E. Seismicity, Faulting and Liquefaction

1. Seismicity

Seismic parameters for the 2024 International Building Code are include in

Appendix B. The following spectral acceleration values are obtained from the

ASCE Hazard Tool for the site:

(S) (g)T Sa

0 0.46

0.01 0.46

0.02 0.46

0.03 0.47

0.05 0.53

0.075 0.63

0.1 0.72

0.15 0.88

0.2 1.01

0.25 1.09

0.3 1.16

0.4 1.18

0.5 1.13

0.75 0.96

1 0.78

1.5 0.54

2 0.4

3 0.24

4 0.15

5 0.1

7.5 0.045

10 0.027

2. Faulting

There are no mapped active faults extending through the project site. The closest mapped surface trace of a potentially active fault is that of the

Granger Fault located approximately 165 feet west of the proposed building

(Utah Geological Survey, 2025). A fault study was performed at the site and is reported in a separate report. Faulted sediments up to approximately 2 inches were encountered in the trench. These potential offsets should be considered in design of the building.

3. Liquefaction

The proposed building is located in an area mapped to have a moderate liquefaction potential (Salt Lake County, 2002). Based on the subsurface conditions encountered at the site, liquefaction is not considered to be a significant hazard.

F. Water Soluble Sulfates

One sample of the natural soil was tested for water soluble sulfate content. The sample contained less than 0.1 percent water soluble sulfates indicating the natural soil possesses negligible sulfate attack potential on concrete. No special cement type is needed for concrete placed in contact with soil having negligible sulfate content.

Other conditions may dictate the type of cement to be used in concrete for the project.

G. Pavement

Based on the subsurface conditions encountered, laboratory test results and the assumed traffic, the following pavement support recommendations are given:

1. Subgrade Support

The near surface soil consists predominantly of clay. A California Bearing

Ratio (CBR) value of 3 percent was used in the analysis, which assumes a clay subgrade.

2. Pavement Thickness

Based on the subsoil conditions encountered at the site, assumed traffic as described in the Proposed Construction section of the report and outlined in the table below, a design life of 20 years for flexible pavement and 30 years for rigid pavement and methods presented by the AASHTO, the following pavement sections have been calculated:

Rigid Pavement Flexible Pavement

Traffic* Portland

Cement Concrete Thickness

Asphaltic Concrete Thickness

Base Course

Thickness

Granular Borrow

Thickness

No Trucks — 5"

3"

6"

Truck Areas — 6"

3"

6"

6"

A rigid pavement section of 6½ inches of Portland cement concrete over 4 inches of base course is recommended for the dumpster approach slab.

3. Pavement Materials and Construction

a. Flexible Pavement (Asphaltic Concrete)

The pavement materials should meet the specifications for the applicable jurisdiction.

b. Rigid Pavement (Portland Cement Concrete)

The rigid pavement thickness given above assumes that the pavement will have aggregate interlock joints and that a concrete shoulder or curb will be provided.

The pavement materials should meet the specifications for the applicable jurisdiction. The pavement thickness indicated above assumes that the concrete will have a 28-day compressive strength of

5,000 pounds per square inch. Concrete should be air entrained with approximately 6 percent air. Maximum allowable slump will depend on the method of placement but should not exceed 4 inches.

4. Jointing

Joints for concrete pavement should be laid out in a square or rectangular pattern. Joint spacings should not exceed 30 times the thickness of the slab or 15 feet, whichever is smallest. The joint spacings indicated should accommodate the contraction of the concrete and under these conditions steel reinforcing will not be required. The depth of joints should be approximately one-fourth of the slab thickness.

H. Continuing Services

A preconstruction meeting should be held with representatives of the owner, project architect, geotechnical engineer, general contractor, earthwork contractor and other members of the design team to review construction plans, specifications, methods and schedule.

The geotechnical engineer should observe the excavation, earthwork, and foundation phases of the work to determine that subsurface conditions are consistent with those used in the analysis and design. The work should be observed and tested to determine that proper compaction has been achieved during site grading and placement of structural fill.

LIMITATIONS

This report has been prepared in accordance with generally accepted soil and foundation engineering practices in the area for the use of the client for design purposes. The conclusions and recommendations included within the report are based on the information obtained from the borings drilled, trench excavated, shear wave velocity measurements, the results of laboratory tests and our experience in the area. Variations in the subsurface conditions may not become evident until additional exploration or excavation is conducted.

If the subsurface conditions, proposed construction or groundwater level is found to be significantly different from what is described above, we should be notified to reevaluate the recommendations given.

APPLIED GEOTECHNICAL ENGINEERING CONSULTANTS, INC.

Douglas R. Hawkes, P.E., P.G.

Reviewed by Jay R. McQuivey, P.E.

DRH/rs

10-1-2025

REFERENCES

International Code Council, 2020; 2021 International Building Code, Falls Church, Virginia.

Salt Lake County, 2002; Surface Rupture and Liquefaction Potential Special Study Areas Map, Salt Lake County, Utah, adopted March 31, 1989, updated March 2002, Salt Lake County Public Works - Planning Division, 2001 South State Street, Salt Lake City, Utah.

Utah Geological Survey, 2025; Utah Geologic Hazards Portal accessed September 17, 2025 at https://maps.geology.utah.gov/hazards.

Vantassel, J.P. and Cox, B.R, 2022. swprepost software code. Accessed September 26, 2025 at https://github.com/jpvantassel/swprepost

Vantassel, J.P. and Cox, B.R, 2024. swprocess software code. Accessed September 26, 2025 at https://github.com/jpvantassel/swprocess

Wathelet, M., 2025. Geopsy 3.4.2 software code. Accessed September 26, 2025 at https://www.geopsy.org/download.php?platform=win64&release=3.4.2.

B-1 B-2

B-3

Trench

Gap due to waterline

P-1

MASW-1

MAM-1

1250534 Exploratory Boring, Percolation Test, Trench and Geophysical Measurement Locations Figure 1

PROPOSED EVIDENCE BUILDING

4451 SOUTH 2700 WEST

TAYLORSVILLE, UTAH0 60 120 feet

Approximate Scale

LEGEND:

Approximate Boring locations.

Approximate Percolation Test location.

Approximate Fault trench location.

Approximate Multi-channel Analysis of Surface Waves (MASW) array location.

Approximate Micronometer Array Measurement (MAM) location.

AutoCAD SHX Text N

B-1 B-2 B-3

El ev at io n/ Fe et

El ev at io n/ Fe et

Elev. 4304½' Elev. 4304' Elev. 4305'

12/12

11/12

8/12

28/12

30/12

23/12

14/12

18/12

13/12

44/12

73/12

16/12

15/12

20/12

12/12

45/12

65/12

27/12

7/12

93/12

50/12

21/12

10/12

26/12

57/12

50/12

46/12

WC = 29

DD = 87

-200 = 92

UC = 1,850

WC = 14

DD = 96

-200 = 99

WSS = 0.001

WC = 18

DD = 90

-200 = 99

WC = 5

DD = 109

+4 = 55 -200 = 6

WC = 19

DD = 96

-200 = 88

WC = 31

DD = 91

-200 = 97

WC = 25

+4 = 13 -200 = 19

WC = 30

-200 = 85

LL = 25

PI = 5

Assumed Finish Floor Level

See Figure 3 for Legend and NotesApproximate Vertical Scale 1" = 8'

Exploratory Boring Logs Figure 21250534

Indicates the depth to free water and number of days after drilling the measurement was taken.

California Drive sample taken. The symbol 10/12 indicates that 10 blows from a 140-pound automatic hammer falling 30 inches were required to drive the sampler 12 inches.

10/12

LEGEND:

Indicates slotted 1½-inch PVC pipe installed in the boring to the depth shown.

NOTES:

1. The borings were drilled on August 26, 2025 with 8-inch-diameter hollow-stem auger.

2. The locations of the borings were measured approximately by pacing from features shown on the site plan provided.

3. The elevations of the borings were determined by interpolating between contours shown on the site plan provided.

4. The boring locations and elevations should be considered accurate only to the degree implied by the method used.

5. The lines between materials shown on the boring logs represent the approximate boundaries between material types and the transitions may be gradual.

6. The water level reading shown on the log was made at the time and under the conditions indicated. Fluctuations in the water level will occur with time.

7. WC = Water Content (%);

DD = Dry Density (pcf);

+4 = Percent Retained on the No. 4 Sieve;

-200 = Percent Passing the No. 200 Sieve;

LL = Liquid Limit (%);

PI = Plasticity Index (%);

UC = Unconfined Compressive Strength (psf);

WSS = Water Soluble Sulfates (%).

Topsoil; lean clay, moist, dark brown, organics.

Silty Sand (SM); occasional gravels, medium dense, moist to wet, brown.

Poorly Graded Gravel with Silt and Sand (GP-GM); clayey zones, medium to very dense, moist to wet, brown.

Lean Clay (CL); occasional thin silt and sand layers, medium to very stiff, moist to wet, brown to gray.

Standard Penetration test. The symbol 10/12 indicates that 10 blows from a 140-pound automatic hammer falling 30 inches were required to drive the sampler 12 inches.

10/12

Exploratory Boring Legend and Notes Figure 31250534

APPLIED GEOTECHNICAL ENGINEERING CONSULTANTS, INC.

TABLE I

SUMMARY OF LABORATORY TEST RESULTS

PROJECT NUMBER: 1250534

SAMPLE

LOCATION NATURAL

MOISTURE

CONTENT

NATURAL

DRY

DENSITY

(PCF)

GRADATION ATTERBERG LIMITS UNCONFINED

COMPRESSIVE

STRENGTH

(PSF)

WATER

SOLUBLE

SULFATE

SAMPLE CLASSIFICATION

BORING DEPTH

(FEET)

GRAVEL

SAND

SILT/

CLAY

LIQUID LIMIT

PLASTICITY

INDEX

B-1 4 29 87 92 1,850 Lean Clay

B-2 2 14 96 99 0.001 Lean Clay

4 18 90 99 Lean Clay

14 5 109 55 39 6 Poorly Graded Gravel with Silt and Sand

B-3 19 19 96 88 Lean Clay

24 31 91 97 Lean Clay

36½ 25 13 68 19 Silty Sand

39 30 85 25 5 Silty Clay with Sand

APPENDIX A

SHEAR WAVE VELOCITY RESULTS

3 4

Project No. 1250534

Ve lo ci ty

(m /s

100 101 102

a) RAW DATA

Ve lo ci ty

(m /s

101 103

Ve lo ci ty

(m /s

Ve lo ci ty

(m /s

101 102101

b) TRIMMED DATA

Frequency (Hz) Wavelength (meters)

Frequency (Hz) Wavelength (meters)

Applied Geotechnical Engineering Consultants, Inc.

LEGEND:

MASW

MAM

Limits Target Experimental Dispersion Data Target Experimental Dispersion Data (min COV=0.05)

Project Name: Proposed Evidence Building Measurement Method: Multi-channel Analysis of Surface Waves (MASW)

Microtremor Array Measurement (MAM)

Location: MASM-1 and MAM-1 Date of Test: September 18, 2025

PEAK DISPERSION DATA

Project No. 1250534

D ep th (f ee t)

Shear Wave Velocity, Vs (ft/s)

SHEAR WAVE VELOCITY PROFILES

Average of Parametrization 1 Average of Parametrization 2 Average of Parametrization 3 Average of Parametrization 4 Best 100 Models for each Parameterization

LEGEND:

Applied Geotechnical Engineering Consultants, Inc.

Project Name: Proposed Evidence Building Measurement Method: Multi-channel Analysis of Surface Waves (MASW)

Microtremor Array Measurement (MAM)

VS30: 890 ± 20 ft/s Location: MASW-1 and MAM-1 Date of Test: September 18, 2025

APPENDIX B

ASCE HAZARDS REPORT

ASCE Hazards Report Address:

No Address at This Location

Standard: ASCE/SEI 7-22 Latitude: 40.6731

Risk Category: III Longitude: -111.955

Soil Class: D - Stiff Soil Elevation: 4304.759245928145 ft

(NAVD 88)

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PGA M : 0.66

SMS : 1.59

SM1 : 1.17

SDS : 1.06

SD1 : 0.78

TL : 8

SS : 1.63

S1 : 0.52

VS30 : 260

Seismic Design Category: D

Multi-Period Design Spectrum

S (g) vs T(s)a

Multi-Period MCE SpectrumR

S (g) vs T(s)a

Two-Period Design Spectrum

S (g) vs T(s)a

Two-Period MCE SpectrumR

S (g) vs T(s)a

Design Vertical Response Spectrum

Vertical ground motion data has not yet been made available by USGS.

MCE Vertical Response SpectrumR

Vertical ground motion data has not yet been made available by USGS.

Seismic

D - Stiff SoilSite Soil Class:

Results:

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