B08_Attachment_2_Volume_2_DINO_NPS_31025_Construction_Specifications_Final_CD_2025-05-30.pdf

Dinosaur National Monument

Yampa District Multi-Operations Facility Project Manual - 100% CD

April 25, 2025

National Park Service

NATIONAL PARK SERVICE

U.S. DEPARTMENT OF THE INTERIOR

VOLUME 2

Project Manual:

Final Construction Documents May 30, 2025

DINO NPS TABLE OF CONTENTS 05-30-2025

TABLE OF CONTENTS

DIVISION 00 - PROCUREMENT AND CONTRACTING REQUIREMENTS

00 01 07 SEALS PAGE

DIVISION 01 - GENERAL REQUIREMENTS

01 11 00 SUMMARY OF WORK

01 26 01 CONTRACT MODIFICATION PROCEDURES

01 27 00 DEFINITION OF CONTRACT LINE ITEMS

01 31 00 PROJECT MANAGEMENT AND COORDINATION

01 32 16 CONSTRUCTION SCHEDULE

01 32 33 PHOTO DOCUMENTATION

01 33 23 SUBMITTAL PROCEDURES

01 35 13.22 ARCHEOLOGICAL PROTECTION

01 40 00 QUALITY REQUIREMENTS

01 40 00.10 STATEMENT OF STRUCTURAL TESTS AND SPECIAL

INSPECTIONS

01 40 00.20 CONSTRUCTION INSPECTION CHECKLIST

01 42 00 REFERENCE STANDARDS

01 50 00 TEMPORARY FACILITIES AND CONTROLS

01 57 19.11 INDOOR AIR QUALITY MANAGEMENT

01 57 19.12 NOISE AND ACOUSTIC MANAGEMENT

01 57 23 TEMPORARY STORM WATER POLLUTION PREVENTION

01 67 00 PRODUCT REQUIREMENTS

01 73 29 CUTTING AND PATCHING

01 73 40 EXECUTION

01 74 19 CONSTRUCTION WASTE MANAGEMENT AND DISPOSAL

01 77 00 CLOSEOUT PROCEDURES

01 78 23 OPERATION AND MAINTENANCE DATA

01 79 00 DEMONSTRATION AND TRAINING

01 91 14 TOTAL BUILDING COMMISSIONING

DIVISION 02 - EXISTING CONDITIONS

02 01 00 HAZARDOUS MATERIAL SUMMARY OF WORK

02 41 00 DEMOLITION

02 41 13 SELECTIVE SITE DEMOLITION

DIVISION 03 - CONCRETE

03 30 00 CAST-IN-PLACE CONCRETE

DIVISION 04 - MASONRY

04 26 13 MASONRY VENEER

DIVISION 05 - METALS

05 12 00 STRUCTURAL STEEL FRAMING

05 21 00 STEEL JOIST FRAMING

05 31 00 STEEL DECKING

05 40 00 COLD-FORMED METAL FRAMING

05 45 00 METAL SUPPORT ASSEMBLIES

05 50 00 METAL FABRICATIONS

05 51 33 METAL LADDERS

05 52 13 PIPE AND TUBE RAILINGS

DIVISION 06 - WOOD, PLASTICS, AND COMPOSITES

06 10 00 ROUGH CARPENTRY

06 20 00 FINISH CARPENTRY

06 83 16 FIBERGLASS REINFORCED PANELING

DIVISION 07 - THERMAL AND MOISTURE PROTECTION

07 11 13 BITUMINOUS DAMPPROOFING

07 18 00 TRAFFIC COATINGS

07 21 00 THERMAL INSULATION

07 21 19 FOAMED-IN-PLACE INSULATION

07 26 00 VAPOR RETARDERS

07 27 00 AIR BARRIERS

07 41 13 METAL ROOF PANELS

07 42 13 METAL WALL PANELS

07 62 00 SHEET METAL FLASHING AND TRIM

07 71 23 MANUFACTURED GUTTERS AND DOWNSPOUTS

07 72 00 ROOF ACCESSORIES

07 92 00 JOINT SEALANTS

07 95 13 EXPANSION JOINT COVER ASSEMBLIES

DIVISION 08 - OPENINGS

08 06 71 DOOR HARDWARE SCHEDULE

08 11 13 HOLLOW METAL DOORS AND FRAMES

08 14 16 FLUSH WOOD DOORS

08 33 23 OVERHEAD COILING DOORS

08 36 13 SECTIONAL DOORS

08 43 13 ALUMINUM-FRAMED STOREFRONTS

08 54 13 FIBERGLASS WINDOWS

08 71 00 DOOR HARDWARE

08 71 13 POWER DOOR OPERATORS

08 80 00 GLAZING

08 83 00 MIRRORS

08 87 23 SAFETY AND SECURITY FILMS

08 91 00 LOUVERS

DIVISION 09 - FINISHES

09 21 16 GYPSUM BOARD ASSEMBLIES

09 30 00 TILING

09 51 00 ACOUSTICAL CEILINGS

09 51 11 ACOUSTICAL LINEAR CEILINGS -ACOUFELT

09 65 00 RESILIENT FLOORING

09 65 66 RESILIENT ATHLETIC FLOORING

09 68 13 TILE CARPETING

09 91 13 EXTERIOR PAINTING

09 91 23 INTERIOR PAINTING

09 93 00 STAINING AND TRANSPARENT FINISHING

09 97 23 CONCRETE AND MASONRY COATINGS

DIVISION 10 - SPECIALTIES

10 14 19 DIMENSIONAL LETTER SIGNAGE

10 26 00 WALL AND DOOR PROTECTION

10 26 41 BALLISTICS RESISTANT PANELS

10 28 00 TOILET, BATH, AND LAUNDRY ACCESSORIES

10 44 00 FIRE PROTECTION SPECIALTIES

10 51 13 METAL LOCKERS

10 73 16.13 METAL CANOPIES

DIVISION 11 - EQUIPMENT

11 30 13 RESIDENTIAL APPLIANCES

DIVISION 12 - FURNISHINGS

12 21 13 HORIZONTAL LOUVER BLINDS

12 35 30 RESIDENTIAL CASEWORK

12 36 00 COUNTERTOPS

12 48 13 ENTRANCE FLOOR MATS AND FRAMES

DIVISION 13 - SPECIAL CONSTRUCTION

13 36 00 TOWERS

DIVISION 21 - FIRE SUPPRESSION

21 00 00 FIRE SUPPRESSION BASIC REQUIREMENTS

21 05 00 COMMON WORK RESULTS FOR FIRE SUPPRESSION

21 08 00 COMMISSIONING OF FIRE SUPPRESSION SYSTEM

21 13 00 FIRE-SUPPRESSION SPRINKLER SYSTEMS

DIVISION 22 - PLUMBING

22 05 00 COMMON WORK RESULTS FOR PLUMBING

22 05 16 EXPANSION FITTINGS AND LOOPS FOR PLUMBING

PIPING

22 05 17 SLEEVES AND SLEEVE SEALS FOR PLUMBING PIPING

22 05 19 METERS AND GAUGES FOR PLUMBING PIPING

22 05 23.12 BALL VALVES FOR PLUMBING PIPING

22 05 23.14 CHECK VALVES FOR PLUMBING PIPING

22 05 29 HANGERS AND SUPPORTS FOR PLUMBING PIPING AND

EQUIPMENT

22 05 48.13 VIBRATION AND SEISMIC CONTROLS FOR PLUMBING

PIPING AND EQUIPMENT

22 05 53 IDENTIFICATION FOR PLUMBING PIPING AND

EQUIPMENT

22 07 19 PLUMBING PIPING INSULATION

22 08 00 COMMISSIONING OF PLUMBING

22 11 16 DOMESTIC WATER PIPING

22 11 19 DOMESTIC WATER PIPING SPECIALTIES

22 11 23.21 INLINE DOMESTIC WATER PUMPS

22 13 16 SANITARY WASTE AND VENT PIPING

22 13 19 SANITARY WASTE PIPING SPECIALTIES

22 33 00 ELECTRIC DOMESTIC WATER HEATERS

22 45 00 EMERGENCY PLUMBING FIXTURES

DIVISION 23 - HEATING, VENTILATING, AND AIR-CONDITIONING (HVAC)

23 05 00 COMMON WORK RESULTS FOR HVAC

23 05 13 COMMON MOTOR REQUIREMENTS FOR HVAC

EQUIPMENT

23 05 29 HANGERS AND SUPPORTS FOR HVAC PIPING AND

EQUIPMENT

23 05 48.13 VIBRATION AND SEISMIC CONTROLS FOR HVAC

23 05 53 IDENTIFICATION FOR HVAC PIPING AND EQUIPMENT

23 05 93 TESTING, ADJUSTING, AND BALANCING FOR HVAC

23 07 13 DUCT INSULATION

23 08 00 COMMISSIONING OF HVAC

23 23 00 REFRIGERANT PIPING

23 31 13 METAL DUCTS

23 33 00 AIR DUCT ACCESSORIES

23 34 16 CENTRIFUGAL HVAC FANS

23 34 39 HIGH-VOLUME, LOW-SPEED PROPELLER FANS

23 37 13.13 AIR DIFFUSERS

23 37 13.23 REGISTERS AND GRILLES

23 81 26 SPLIT-SYSTEM AIR-CONDITIONERS

23 81 29 VARIABLE REFRIGERANT FLOW HVAC SYSTEMS

DIVISION 26 - ELECTRICAL

26 05 00 COMMON WORK RESULTS FOR ELECTRICAL

26 05 19 LOW-VOLTAGE ELECTRICAL POWER CONDUCTORS AND

CABLES

26 05 26 GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS

26 05 29 HANGERS AND SUPPORTS FOR ELECTRICAL SYSTEMS

26 05 33 RACEWAYS BOXES FOR ELECTRICAL SYSTEMS

26 05 44 SLEEVES AND SLEAVE SEALS FOR ELECTRICAL

RACEWAYS AND CABLING

26 05 48 VIBRATION AND SEISMIC CONTROLS FOR ELECTRICAL

SYSTEMS

26 05 53 IDENTIFICATION FOR ELECTRICAL SYSTEMS

26 05 73 ELECTRICAL SYSTEM STUDIES

26 08 00 COMMISSIONING OF ELECTRIC SYSTEMS

26 09 23 LIGHTING CONTROL DEVICES

26 09 43 NETWORK LIGHTING CONTROLS

26 22 00 LOW-VOLTAGE TRANSFORMERS

26 24 13 SWITCHBOARDS

26 24 16 PANELBOARDS

26 27 13 ELECTRICITY METERING

26 27 26 WIRING DEVICES

26 28 16 ENCLOSED SWITCHES AND CIRCUIT BREAKERS

26 32 13 ENGINE GENERATORS

26 36 00 TRANSFER SWITCHES

26 41 13 LIGHTNING PROTECTION FOR STRUCTURES

26 43 13 TRANSIENT-VOLTAGE SUPPRESSION FOR LOW-VOLTAGE

ELECT

26 51 00 LIGHTING FIXTURES

DIVISION 27 - COMMUNICATIONS

27 00 10 SUPPLEMENTAL REQUIREMENTS FOR

COMMUNICATIONS

27 05 26 GROUNDING AND BONDING FOR COMMUNICATION

SYSTEMS

27 05 28 PATHWAYS FOR COMMUNICATION SYSTEMS

27 05 53 IDENTIFICATION FOR COMMUNICATION SYSTEMS

27 11 16 COMMUNICATIONS RACKS, FRAMES, AND ENCLOSURES

27 13 13 COMMUNICATIONS COPPER BACKBONE CABLING

27 13 23 COMMUNICATIONS OPTICAL FIBER BACKBONE

27 15 13 COMMUNICATIONS COPPER HORIZONTAL CABLING

27 41 00 AUDIO VISUAL SYSTEMS

DIVISION 28 - ELECTRONIC SAFETY AND SECURITY

28 00 01 ELECTRIC SAFETY BASIC REQUIREMENTS

28 00 10 SUPPLEMENTAL REQUIREMENTS FOR ELECTRONIC

SAFETY AND SECURITY

28 08 00 COMMISSIONING OF FIRE ALARM

28 13 00 ACCESS CONTROL SOFTWARE AND DATABASE

MANAGEMENT

28 14 00 ACCESS CONTROL SYSTEM HARDWARE

28 16 00 INTRUSION DETECTION

28 20 00 VIDEO SURVEILLANCE

28 46 00 FIRE DETECTION AND ALARM

DIVISION 31 - EARTHWORK

31 10 00 SITE CLEARING

31 20 00 EARTH MOVING

31 23 16 TOPSOIL

31 25 00 EROSION AND SEDIMENTATION CONTROL

DIVISION 32 - EXTERIOR IMPROVEMENTS

32 12 16 ASPHALT PAVING

32 13 20 SITE CONCRETE

32 17 00 PAVING SPECIALTIES

32 31 13 CHAIN LINK FENCES AND GATES

32 33 00 SITE FURNISHINGS

32 92 19 SEEDING

DIVISION 33 - UTILITIES

33 10 00 WATER UTILITIES

33 16 00 WATER UTILITY STORAGE TANKS

33 30 00 SANITARY SEWERAGE

33 40 00 STORM DRAINAGE

33 46 00 SUBDRAINAGE

APPENDIX

01 GEOTECHNICAL REPORTS

August 16,2024 - Geotechnical Engineering Report - Prepared by Jorgensen Geotchnical, LLC

02 HAZARDOUS MATERIAL REPORTS

� Hazardous Materials Assessment Summary for Dinosaur National Monument, Yampa District Multi-Operation Facility, Yampa, CO dated May 21, 2024 - Prepared by Landmark Environmental, Inc.

03 EXISTING STRUCTURE REPORT

1. Multi-Ops Facility - Existing Building dated April 2024 - Prepared by Otak, Inc

2. Structural Evaluation Report Yampa District Maintenance Building, Dinosaur National Monument, Dinosaur, Colorado, dated February 17, 2014 prepared by JVA, Inc. includes: February 3, 2014 - Geotechnical Engineering Report - Prepared by Yeh and Associates, Inc.

04 EXISTING BUILDING DRAWINGS

Existing Building Drawings_Maintenance and Storage Building dated 9/19/1962.

- VOLUME 2

August 16, 2024

Chad Weiser Otak, Inc.

11241 Willow Road NE Suite 200 Redmond, WA 98052

RE: GEOTECHNICAL-ENGINEERING REPORT, PROPOSED REPLACEMENT YAMPA DISTRICT MULTI-OPERATIONS

FACILITY, DINOSAUR NATIONAL MONUMENT, MOFFAT COUNTY, COLORADO

PROJECT NO: 24402

Dear Mr. Weiser, We are pleased to present this Geotechnical-Engineering Report on our geotechnical site exploration for the proposed Yampa District replacement multi-operations facility in Dinosaur National Monument, in Moffat County, Colorado. This report describes site conditions observed during the subsurface exploration and presents engineering analyses and recommendations to support the design and construction of foundation elements for the new facility and parking lot design.

Jorgensen Geotechnical explored subsurface conditions via boring six (6) exploratory boreholes spanning the east and west sides of proposed multi-operations facility. In general, the site is underlain by lean clays and silty sands, identified as colluvium, overlying variable bedrock. Laboratory results indicate these deposits are moisture-sensitive, prone to settlement, expansive, and collapsible. Therefore, the native, unimproved colluvium is not recommended as a bearing layer for foundation elements. We recommend a mat foundation bearing on reinforced, non-frost-susceptible fill, underlain by one-foot of recompacted native colluvium, with strategically placed drainage to control moisture.

We also include a section on pavement design for the re-design of the parking area on-site. Based on our calculations, the subbase thickness for an asphalt parking lot is 7 inches, with a base course thickness of 6 inches.

If you have any questions about this report, or if we may provide other services to you, please contact us. As the project progresses, we will be available to answer questions for you.

Respectfully submitted, JORGENSEN GEOTECHNICAL

Marlie Schell, M.S. Travis Halverson, P.E.

Geotechnical Design Engineer Technician Geotechnical Project Manager

Geotechnical-Engineering Report Yampa District Multi-Operations Facility | Dinosaur National Monument

Moffat County, Colorado

40.245097°N, -108.972220°W

Date: August 16, 2024

PR

EP

AR

ED

F O

R

PR

EP

AR

ED

B Y

Jorgensen Geotechnical, LLC PO Box 9550

1315 HWY 89 S., Ste. 201 Jackson, WY 83002

Chad Weiser Otak, Inc.

11241 Willow Road NE Suite 200 Redmond, WA 98052 i

CONTENTS

1.0 PROJECT BACKGROUND

2.0 INTRODUCTION

3.0 REPORT SUMMARY

4.0 PROJECT DESCRIPTION

5.0 SITE CONDITIONS

5.1 DESCRIPTION

5.2 SUBSURFACE SOIL CONDITIONS

5.3 GROUNDWATER

5.4 EARTHQUAKES AND SEISMICITY

5.5 GEOTECHNICAL HAZARDS: EXPANSIVE AND COMPRESSIBLE SOILS AND BEDROCK

5.5.1 Heave

5.5.2 Settlement

6.0 GEOTECHNICAL RECOMMENDATIONS

6.1 RECOMMENDATIONS OVERVIEW

6.2 WATER MANAGEMENT

6.2.1 Foundation Drains

6.3 OVER-EXCAVATION AND REINFORCED FILL

6.4 MAT FOUNDATION

6.4.1 Modulus of Subgrade Reaction

6.4.2 Void Form

6.5 DEEP FOUNDATION ELEMENTS

6.6 EARTHWORK

6.6.1 Site Preparation

6.6.2 Excavation and Cut Slope Stability

6.6.3 Fill Material Types and Compaction Requirements

6.6.4 Final Backfilling and Grading

6.6.5 Reinforcing, Utilities Testing, and Concrete Considerations

6.6.6 Observation during Construction

6.7 LATERAL EARTH PRESSURES

6.7.1 Active Pressures

6.7.2 At-Rest Pressures

6.7.3 Passive Pressures

6.8 SLABS-ON-GRADE

6.9 PAVEMENT DESIGN

6.9.1 Flexible Pavement

6.9.2 General Pavement Recommendations

7.0 LIMITATIONS

8.0 REFERENCES

Note: Clicking on a desired section in the table of contents will direct the reader to that section and clicking on the Jorgensen logo in the upper left of the page will bring you back to this page.

ii

FIGURES

Figure 1: Site Location and Geologic Map Figure 2: Test Pit and Cross-Section Location Map Figure 3: Cross-Section A-A’ Figure 4: Cross-Section B-B’ Figure 5: Cross-Section C-C’ Figure 6: Cross-Section D-D’ Figure 7: Foundation Drains Figure 8: Over-Excavation and Reinforced Fill

TABLES

Table 5-1: Subsurface Soils - Colluvium Table 5-2: Subsurface Rock Table 5-3: U.S. Seismic Design Maps Summary Table 5-4: Anticipated Settlement of Shallow Spread Footings Placed on Unimproved Native Colluvium11 Table 6-1: Calculated Settlement for Spread Footings Table 6-2: Decrease in Settlement of Shallow Spread Footings Due to Reinforced Fill Construction Table 6-3: Soil Uses and Compaction Requirements Table 6-4: Compaction Parameters for Stony Fill Table 6-5: Lateral Pressure Parameters for Native Colluvium Table 6-6: AASHTO Flexible Pavement Design Parameters Table 6-7: Flexible Pavement Design - Base and Subbase Thicknesses

APPENDICES

Appendix A: Figures Appendix B: Site Exploration Procedures and Subsurface Exploration Logs Appendix C: Laboratory Testing Results Appendix D: Settlement Methodology and Calculations Appendix E: Micropile Design

Jorgensen Geotechnical, LLC August 16, 2024 Geotechnical-Engineering Report – Yampa District Multi-Operations Facility Dinosaur National Monument, Moffat County, CO

1.0 PROJECT BACKGROUND

The existing Yampa District multi-operations facility was constructed in 1963 and appears to have been originally constructed on shallow spread footings. A geotechnical-engineering subsurface exploration was completed prior to construction in 1962 by Dames and Moore. Distress to the building began shortly after construction according to the NPS. Forensic geotechnical-engineering studies were completed in 1971 by Dames and Moore, in 1983, 1988, and 1989 by the National Park Service (NPS), in 1991 by Delta Geotechnical Consultants, Inc, and in 2014 by Yeh and Associates, Inc. Most of these studies focused on settlement as the mechanism causing the distress.

A 1983 memorandum from the NPS recommended steel piers be installed near the southwest corner of the building and also noted a previous water line break. In fall 1983 steel piles were installed at the southwest corner of the building. In late 1997 and early 1998, a compaction grouting program was completed beneath the existing building.

Yeh and Associates, Inc. (Yeh) stated in their 2014 report, “From our review of the available information there does not appear to be a clear cause to the movement and distress experienced by the maintenance building. We believe that settlement may be a contributing factor in the movement; however, our investigation has indicated that heave from expansive soils and bedrock is also a likely factor in the movement of the building.” Yeh indicated that the claystone bedrock was potentially expansive, and the compaction grouting may have made the distress to the existing building worse. Yeh recommended a deep foundation system, with micropiles listed as the most suitable deep foundation system. Structural slabs supported by deep foundation elements were also recommended. Yeh indicated that additional subsurface exploration would be needed for design of deep foundation elements.

2.0 INTRODUCTION

Jorgensen Geotechnical, LLC (JG), was commissioned by Otak, Inc. (Otak) to perform a subsurface exploration for the proposed Yampa District multi-operations facility replacement located in Moffat County, Colorado (Figure 1).

Our specific scope of services is described in the work plan dated March 26, 2024. The purposes of the exploration were to provide information and geotechnical-engineering recommendations pertaining to:

Subsurface soil conditions Site preparation and earthwork Evaluation of settlement and swell potential Seismic site classification per the

International Building Code

Foundation design and construction recommendations

Slab design and construction recommendations

Pavement design recommendations

The scope of services for this project included logging six (6) exploratory boreholes which ranged in depth from 28 to 63.5-ft below ground surface (bgs) in the vicinity of the proposed multi-operations facility. Figures are presented in Appendix A, a detailed description of the subsurface exploration and graphical logs are shown in Appendix B, laboratory testing results are included as Appendix C, settlement calculations are included in Appendix D, and micropile design discussion in Appendix E.

Dinosaur National Monument, Moffat County, CO

3.0 REPORT SUMMARY

Jorgensen Geotechnical (JG) explored subsurface conditions by reviewing previous geotechnical and structural analyses reports, and by logging soils from six (6) exploratory boreholes spanning the project site. Approximate borehole locations are shown in Figure 2. In general, the site is underlain by colluvium, comprising silty sand and lean clay, overlying sandstone, and claystone bedrock deposits from the Mancos Shale Formation. The colluvium is compressible and the claystone is potentially expansive. Typical spread footings bearing directly on the colluvium are NOT an adequate foundation for these soil types due to potential settlement. To reduce the risk of differential movement, we recommend site improvements and subgrade improvement at this site to include:

1. Surface and subsurface water management

2. A shallow mat foundation

3. Subgrade improvement comprising a reinforced fill

We identified the following as specific geotechnical-engineering considerations for this project site:

site soils include moisture-sensitive soils that are both compressible and expansive, careful management of water both on the surface below the surface will be necessary, during and post-construction, seismic and fault-related hazards are low.

We have included a pavement design section that gives recommendations for the proposed asphalt parking lot.

4.0 PROJECT DESCRIPTION

Proposed construction includes replacing the Yampa District multi-operations facility, the fuel system, security fences and gates, parking surfaces and constructing a boat wash station with an oil/water separator and upgrading utilities. Replacement of the on-site wastewater treatment system (OWTS) is discussed in a separate report. Based on a preliminary site layout provided by Otak, Inc., the proposed new building will be situated north-south, with the northern portion of the proposed building occupying the eastern portion of the area currently occupied by the existing building, as shown in Figure 2. We understand the project design team has selected a foundation system comprising a mat foundation without turn-down edges. Frost protection will be provided by placing a non-frost-susceptible imported aggregate extending down below the required frost depth.

The project design team is considering either separating the storage garage and the office spaces into two separate structures or connecting the two portions of the building with a flexible joint.

Figure 1: Site Location and Geologic Map

5.0 SITE CONDITIONS

5.1 Description

JG developed the following description of the site based on meetings with Otak, our review of available historical aerial imagery, and observations made during the subsurface exploration.

Item Description

Location and Parcel Information

The site is located approximately 500-ft north of the Canyon Visitor Center of Dinosaur National Monument, east of Dinosaur, Colorado at 4545 U.S. 40.

Existing Improvements

The project site is asphalt-paved and enclosed by chain-link fences and several gates. The site includes the existing multi-operations facility, a river ranger garage, fuel station, parking areas, bathroom and several Conex storage containers.

Current Ground Cover

Ground cover includes an asphalt parking lot and the existing multi-operations facility.

Existing Topography

According to a topographic survey provided by Otak, dated April 16, 2024, the project site rests between two ridges and slopes gently from east to west ranging in elevation from approximately 5,964 to 5,958 feet AMSL (above mean sea level). North of the site, a ridge of Dakota Sandstone outcrops to over 6,030 feet AMSL and to the south the Mancos Shale Formation outcrops into a ridge system spanning east-west, over 6,000 feet AMSL.

Geologic Setting

The project site is found on the Geologic Map of the Mellen Hill Quadrangle (Cullins, 1969), which is adapted as Figure 1. The map shows the location of surficial deposits, bedrock units, and geologic structures (i.e., faults and folds). The map indicates the project site is situated between ridges of the Dakota Sandstone (Kd) and Mancos Shale (Km/Kmf/Kmm). The site is covered by Quaternary-aged alluvial and colluvial deposits (Qac) which are expected to be underlain with units from the Dakota Sandstone and Mancos Shale. Mancos Shale deposits historically exhibit expansive qualities. The observations during the subsurface exploration agree with mapped geology.

Dinosaur National Monument is in an area of low seismicity. The closest faults are undifferentiated Quaternary-aged that are not expected to be a risk to the proposed construction. The thrust faults shown on the geologic map are expected to be deep and inactive.

5.2 Subsurface Soil Conditions

Four soil types and three rock types were generally observed to cover the site. Soils include silty sand, sandy silt, sandy lean clay and lean clay with gravel. Geologic maps indicate they are colluvial or alluvial in origin (i.e., gravity or water transported). The variable soil types within the colluvial layer are assumed to be derived from differing source rocks and are therefore variable. Though the soil classifications are different, their engineering properties are assumed to be similar due to the uniform depositional environment. For the purposes of this report, all the soils are referred to “colluvium”.

Rock types underlying the colluvium encountered on the project site include siliceous sandstone, claystone, and shale. The sandstone is from the Dakota Formation and the shale and claystone are from the Mancos Shale Formation. The interpreted subsurface conditions are depicted in Figure 3, Figure 4, Figure 5, and Figure 6.

The table below describes each soil and rock layer, and detailed borehole logs are represented graphically in Appendix B. We have also included the logs from the 2014 Yeh and Associates subsurface exploration in

Dinosaur National Monument, Moffat County, CO

Appendix B. Asphalt and a thin layer of base course (approximately 6 inches in thickness) were observed beginning at the surface of every borehole.

Table 5-1: Subsurface Soils - Colluvium

Layer Layer Name Description Geotechnical Considerations and Uses

Silty Sand

(SM)

• Observed in JG-1 through JG-4

• Beginning below the base course and extending up to 18-ft bgs

• Orangish-brown

• Very loose to loose

• Up to 7% gravel

• 55-73% sand

• 26-40% clay/silt

• Compressible

• Frost heave

• Moisture-sensitive

• Non-Structural applications

2 Sandy Silt (ML)

• Observed in JG-5

• Beginning at 4-ft bgs and extending up to 10.3-ft bgs

• Orangish-brown

• Very loose

• 1% gravel

• 37% sand

• 62% clay/silt

• Compressible

• Frost heave

• Moisture-sensitive

3 Sandy Lean Clay

(CL)

• Observed in JG-3, JG-4, JG-5 and JG-6

• Beginning at approximately 2-ft and extending up to 49-ft bgs and intermittent lenses

• Grayish brown

• Very soft to very stiff

• Medium plasticity

• Up to 7% gravel

• 20-42% sand

• 51-80% Clay/Silt

• Compressible

• Expansive

• Frost heave

• Moisture sensitive

4 Lean Clay with Gravel

(CL)

• Observed in JG-3 and JG-6

• Beginning at approximately

17-ft and extending up to 22.5-ft bgs and intermittent lenses

• Brownish gray

• Medium stiff

• Medium plasticity

• 10-20% gravel

• 15-32% sand

• 59-72% fines

• Compressible

• Expansive

• Moisture sensitive

Dinosaur National Monument, Moffat County, CO

Table 5-2: Subsurface Rock

Layer Layer Name Description Geotechnical Considerations and Uses

1 Sandstone [Dakota Formation]

• Observed in JG-1, JG-2, JG-4 and JG-6

• Observed ranging from 8-ft to 28-ft bgs in JG-1 and JG-2, at 59.5-ft bgs in JG-4, and 41.5 to 44.5-ft bgs in JG-6

• Light gray and siliceous

• Interbedded with coal or claystone

• Generally dipping at 45°

• Completely weathered to unweathered

• Acceptable

Bearing Layer

Shale

[Mancos Shale Formation]

• Observed in JG-3 and JG-6

• Observed at intermittent depths

• Dark gray

• Soft and fissile

• Close-spaced fractures

• Completely weathered to moderately weathered

• Siliceous

• Moisture sensitive

• Expansive

Claystone

[Mancos Shale Formation]

• All boreholes at depth

• Observed as the deepest layer in all boreholes, beginning at approximately 19.5-ft bgs and extending to the bottom of all boreholes

• Dark gray

• Close-spaced fractures

• Soft and shattered

• Freshly weathered to moderately weathered

• Bedding angle ranges from 0° to 45°

• Moisture sensitive

• Expansive

• At depth, not expected to affect shallow foundations

Figure 2: Test Pit and Cross-Section Location Map

Figure 3: Cross-Section A-A’

Figure 4: Cross-Section B-B’

Figure 5: Cross-Section C-C’

Figure 6: Cross-Section D-D’

5.3 Groundwater

Groundwater was observed in JG-3, JG-4, and JG-6 at depths ranging from 39-ft to 55.8-ft bgs. Due to its depth, groundwater is not expected to affect design or construction. Groundwater levels are likely influenced primarily by snow melt and seasonal precipitation. Soil moisture conditions on this site are most likely influenced by surface infiltration due to precipitation.

5.4 Earthquakes and Seismicity

Dinosaur National Monument is in an area of relatively low seismic activity. This area is isolated from major fault systems, however, ground motion accelerations should be derived for the project site in accordance with the general procedure defined in the International Building Code (IBC). The IBC references ASCE 7-16 to determine the ground motion accelerations. Based on subsurface soils and the mapped geology, the site is classified as Site Class D (“Stiff Soil”). For your convenience, Seismic Design Maps (SEAOC, 2024) values are summarized in Table 5-3: U.S. Seismic Design Maps Summary. We have assumed risk category IV for this structure based on correspondence with the project design team. If the risk category for the proposed building differs from this assumption, the values presented below should be reevaluated.

Dinosaur National Monument, Moffat County, CO

Table 5-3: U.S. Seismic Design Maps Summary

Maximum Considered Earthquake (MCE) Spectral Response Acceleration Parameters

Short Period (Ss) = 0.319 1-Second Period (S1) = 0.077

Site Coefficients and Adjusted MCE Spectral Response Acceleration Parameters

Fa = 1.545 SMS = 0.493 *Fv = 2.4 *SM1 = 0.188

Design Spectral Response Parameters

SDS = 0.329

*SD1 = 0.126

*Note: Values for Fv, SM1, and SD1 were determined in accordance with Section 11.4.4 of ASCE 7-16. Per Section 11.4.8 of ASCE 7-16, if the proposed structure foundation will include seismic isolators or damping systems, a site response analysis shall be performed in accordance with Section 21.1.

The project site is located in an area of low seismic activity. The current peak horizontal acceleration (PGA) with a probability of occurrence of 2% in 50 years is approximately 0.192g (USGS, 2014). The site amplification factor at PGA is 1.417, resulting in a site modified peak ground acceleration (PGAM) of 0.271. This has been applied for the analysis of seismic lateral loading on retaining walls Section 6.7.

The provisions of the IBC are intended to provide uniform levels of performance for structures depending on their intended occupancy and use, and the risk inherent to their failure. The approach adopted in the IBC is intended to provide a uniform margin of safety against collapse at the design motion. The design earthquake ground motion is selected at a ground shaking level that is 2/3 of the maximum considered earthquake (MCE) ground motion, which has a likelihood of exceedance of 2% in 50 years (corresponding to a return period of 2,500 years). The owner should be aware that the IBC is not intended to prevent damage or loss of function during a major earthquake; it is intended to reduce the risk of loss of life.

5.5 Geotechnical Hazards: Expansive and Compressible Soils and Bedrock The subsurface soils at this site are potentially compressible, collapsible, and/or expansive. The combination of these properties creates a risk of differential movement.

Settlement typically occurs gradually after a load is applied. Collapse and swelling (heave) of soil can happen more rapidly and can occur at any time. Collapse and swelling are typically the result of changes in moisture content of the soil. If the proposed building experiences both settlement and heave, the differential movement will likely exceed acceptable levels.

5.5.1 Heave

Laboratory testing for swell potential and swell pressure was performed on in-situ and disturbed samples for both the colluvium and the claystone. The disturbed and remolded samples appeared to exhibit artificially high swell potential and swell pressures compared to the relatively undisturbed samples. Based on testing performed on relatively undisturbed samples, we anticipate the swell pressures of the in-situ colluvium and claystone to be on the order of 400-600 psf. A discussion on swell testing results are listed in Appendix C.

Dinosaur National Monument, Moffat County, CO

We present several techniques to mitigate the effects of the expansive soils. These techniques are presented in Sections 6.2, 6.3, and 6.4. The combination of these techniques will help to mitigate the risk of damage due to the differential settlement caused by heave, however the effect is difficult to quantify. The most important mitigation technique is water management, as the expansive soils will not heave unless wetted.

5.5.2 Settlement

Laboratory testing on the native colluvium show that foundation elements placed directly on the native colluvium have a moderate settlement potential. Lab results indicate the silty sand (SM) collapsed up to 6.7% volumetrically under loads representative of those associated with the proposed construction. This sample was remolded from a disturbed sample and the results may be artificially high. The relatively undisturbed colluvium samples had collapse values between 0.06% to 0.77%.

We calculated settlement of spread footings placed directly on unimproved native soils at three different foundation loads using methods from Das, 2011. The foundation for the proposed structure has not been designed yet, but we recommend a mat foundation in Section 6.4. We calculated settlement for bearing pressures of 1,000 psf, 1,500 psf, and 2,000 psf for 3-ft wide continuous, shallow spread footings. These calculations assume the footings would be placed in direct contact with the native, unimproved colluvium and are summarized below in Table 5-4. These calculations are for reference only and are presented to show the compressible nature of the native colluvium. If a mat foundation is selected as the foundation system, the settlement will depend on the dimensions and loading of the mat foundation. Anticipated differential settlement for a mat foundation can be estimated at 0.75-in for total slab movement of up to 2-in (Bowles, 1996).

Table 5-4: Anticipated Settlement of Shallow Spread Footings Placed on Unimproved Native Colluvium

Bearing Pressure (psf)

Calculated Settlement (inches)

1,000 1.83

1,500 2.45

2,000 2.97

The calculated settlement for shallow spread footings placed in direct contact with the native colluvium is anticipated to cause foundation and slab damage, with the potential for cracking in foundation elements.

Mitigation techniques to reduce the potential for future differential settlement are discussed below, in Section

6.0. Settlement calculations for are presented in Appendix D.

6.0 GEOTECHNICAL RECOMMENDATIONS

6.1 Recommendations Overview

The native colluvium and claystone bedrock are NOT suitable bearing layers for the anticipated foundation loads. To reduce the risk of differential movement, we recommend utilizing a mat foundation placed on a reinforced fill section with adequate surface and subsurface drainage. We present several options for reinforced fill thickness and the calculated settlements for shallow spread footings.

Dinosaur National Monument, Moffat County, CO

Our recommendations are multi-faceted, and require all components be employed to reduce the risk of future differential movement. The recommendations require the following :

1. Careful water management – surface drainage, foundation drains, and drains in the bottom lift of the reinforced fill

2. Reinforced fill with geosynthetic at its base and every 1-ft above

3. Mat foundation

Additionally, a recommendation to reduce the probability of differential movement is separating the multi-operations facility into two separate structures. The benefit of separating the building into two smaller buildings is that differential movement will be smaller over a shorter span. We understand that a flexible joint between the two sections of building is being considered. We recommend either separating the buildings or including a flexible joint between the two sections of building be included in the final design.

6.2 Water Management

Management of water at this site is a very important component of our recommendations and will be paramount in the performance of a structure at this site. Any surface water should be prevented from entering the subsurface near the proposed facility and any subsurface water near the foundation should be adequately controlled and dispensed away from any structures.

Careful design of the drainage surrounding the new facility is of the utmost importance. All water should be discharged such that it does not impact the existing river ranger garage or any other structures on the site.

• Surface drainage o Sheet flow - all surfaces surrounding the proposed building should be designed to sheet flow away from the structure. Surfaces should be a sloped at a minimum of 3% for the first 10-ft from the building.

o Gutter discharge – all gutters should be discharged a minimum of 5-ft from the building o Irrigation – all irrigation should be conducted an adequate distance away from the proposed building such that water does not pond or pool near the building.

o Boat wash station and fire truck filling station – Ensure water is not sloping towards, ponding or pooling near the building.

• Subsurface water:

o Double encase water, sewer, and irrigation lines within 50-ft of the building o Drains installed in base of reinforced fill o Foundation drains o Drains should discharge in the drainage on the west side of the parking lot or dry wells o Dry wells should be placed a minimum of 100-ft away from the new building or any existing structures

Due to the moisture sensitivity of both the soils and bedrock at this site, water must be carefully managed. This includes surface water from precipitation during and after construction, and water or sewer lines. All surface and subsurface water should be discharged into the drainage to the west of the existing buildings, or a drywell located a minimum of 100-ft from any structures. Water, sewer, and irrigation lines should be double encased within 50-ft of the building to capture water from any leaks. Careful management of water at all stages of this project will be paramount to the performance of the structure.

Dinosaur National Monument, Moffat County, CO

6.2.1 Foundation Drains

Due to the moisture sensitivity and anticipated poor drainage properties of site soils, proper drainage is extremely important throughout the entirety of the project site. We recommend constructing drains at the base of the reinforced fill (Figure 8) and foundation drains around the base of the mat foundation (Figure 7).

We present the recommended foundation drainage preparation in aggregate, as presented in Figure 7, below:

• The drainage will consist of placement of clean angular drain gravel or crushed stone between the mat foundation and the edge of the excavation. Drainage tiles, perforated pipe, or other approved systems should be installed at or below the area to be protected and should discharge by gravity or mechanical means into an approved drainage system. The drain pipe may slope at a minimum of 0.5% and drain to daylight or a sump. Gravel drains should extend at least 1 foot beyond the outside edge of the mat. The gravel backfill is wrapped in an approved filter fabric. Compacted backfill (sloped to drain) is placed above the gravel envelope. The advantage of this technique is that the gravel backfill can usually be placed without compaction, reducing backfill cost and difficulty.

It is important to place the foundation drains low enough to adequately collect and discharge any water that may accumulate in the gravel capillary break beneath concrete slabs. Drains that are placed too shallow or with insufficient gradient may fail to perform. JG is available to review the foundation drain design to ensure consistency with our recommendations.

In addition to designing surface drainage and drainage at the base of the foundation, we also recommend placing at least three perforated drains at the bottom of the reinforced fill, sloped a minimum of 2% and discharged away from the building with other surface and subsurface water. The reinforced fill and included drains are illustrated on Figure 8.

Due to the expansive properties of the soils observed at this site, installation of foundation drains, and drains within the reinforced fill will require great care to assure adequate performance of the drainage system and reduce the risk of wetting of the expansive soils and bedrock underlying the site.

Figure 7: Foundation Drains

6.3 Over-Excavation and Reinforced Fill

The calculated settlements presented in this section are for informational purposes and settlements of a mat foundation depends on final foundation dimensions and loading. “Reinforced fill” for the purpose of this Report is the thickness of fill the design team for the multi-operations facility selects. The selected reinforced fill thickness should balance cost, constructability, acceptance of risk by the NPS and the project team, and potential impacts to the structural design. An added benefit of the reinforced fill will be reducing the effects of heave from the underlying soils and bedrock by spreading out the heave forces over a larger area of the foundation, and increasing the effective stress due to the soil on the expansive materials.

We recommend over-excavation and replacement of the native colluvium with a geosynthetic-reinforced fill. We present three options for reinforced fill thickness: 3-feet, 4-feet and 5-feet. The final determination of the thickness of the reinforced fill shall be determined by the project design team at the direction of the NPS.

Factors affecting the decision on how thick the reinforced fill will balance cost, constructability concerns, accepted risk to the building, and impacts to the structural design.

Dinosaur National Monument, Moffat County, CO

Table 6-1: Calculated Settlement for Spread Footings

Calculated Settlement of Spread Footings Placed Directly on the Following Materials (inches)*

Bearing Pressure (psf)

Native Colluvium**

3-ft Thick Reinforced Fill

4-ft Thick Reinforced Fill

5-ft Thick Reinforced Fill

1,500 2.45 1.04 0.73 0.39

*Values assume reinforced fill section will experience no long-term settlement. Settlement values represent anticipated settlement of colluvium only *Values presented in Table 5-4

These calculations are for reference only. If a mat foundation is selected as the foundation system, the settlement will depend on the dimensions and loading of the mat foundation. For a mat foundation, the differential settlement can be estimated at 0.75-in for total slab movement of up to 2-in (Bowles, 1996).

Foundation settlements in excess of 1-inch are typically considered unacceptable. To further outline the benefits and risk reduction of reinforced fill, we present the decrease in settlement of spread footings due to construction of a reinforced fill of 3, 4, and 5-ft thick in Table 6-2.

Table 6-2: Decrease in Settlement of Shallow Spread Footings Due to Reinforced Fill Construction

Bearing Pressure (psf) 3-ft Thick Reinforced Fill

4-ft Thick Reinforced Fill

5-ft Thick Reinforced Fill

1,500 43% 60% 79%

Another benefit of constructing a reinforced fill beneath foundation elements is the dispersal of heaving forces.

The benefit of dispersing heaving forces is to minimize differential movement of the soils and ultimately the foundation elements. This benefit is difficult to quantify.

Over-excavation of unsuitable soils laterally beyond the foundation shall extend a minimum of one footing width for strip footings or the thickness of the over-excavation for a mat foundation. The native colluvium exposed at the base of the over-excavation should be over-excavated an additional 1-ft and recompacted to 95% of the maximum dry density according to Standard Proctor testing (ASTM D698). The recompacted layer of native material should be sloped a minimum of 1% in the same direction as the drain pipes installed in the first lift of the reinforced fill and separated from the native soils with a woven, moisture wicking, geotextile, such as Mirafi H2Ri or performance equivalent. The woven geotextile should separate the native soils from the structural fill on the bottom and sides of the excavation.

If fill, compacted grout columns, or steel piles from previous construction and attempts repair the existing multi-operations facility are encountered in the over-excavation, the grout columns and steel piles should be removed a minimum of 3-ft below the bottom of the reinforced fill. If full removal of the compacted grout columns or steel piles is possible, that is preferred. Any fill that is encountered should be fully removed to expose native soils. Careful backfill of the voids left by removal of the columns or piles will be necessary.

Care should be taken during the over excavation to not allow surface water to enter the excavation prior to installation of drainage. Imported structural fill should consist of a non-frost-susceptible, granular material approved for use as structural fill and compacted per the requirements listed in Section 6.6.3. Non-frost-susceptible material should contain less than 6% by mass passing the #200 sieve. Fill placed on the woven geotextile does not need to conform to additional gradation specifications because the strength is derived from friction, rather than interlocking action.

Dinosaur National Monument, Moffat County, CO

Constructing drains in the bottom lift of the reinforced fill will allow for the collection and discharge of any errant subsurface water that enters the reinforced fill and prevent it from wetting the native soils beneath the building. Drainage pipes placed in the bottom lift of the reinforced fill should be sloped at a minimum of 2% and discharged away from the building with other surface and subsurface water. The drain is illustrated in Figure 8.

Layers of woven geotextile, such as Mirafi RS280i or performance equivalent, should be placed at the one-foot intervals throughout the structural fill as shown on Figure 8 and compacted (i.e., geotextile placed every foot, resulting in three to five layers, depending on the chosen reinforced fill thickness, of geotextile within the reinforced fill). The imported structural fill should be placed and compacted according to recommendations in Section 6.6.3.

Figure 8: Over-Excavation and Reinforced Fill

6.4 Mat Foundation

A mat foundation will offer additional risk reduction of damage to the structure if differential movement of the subsurface soils occurs. A flexible mat foundation will allow the foundation to flex and accommodate minor movement of the subgrade soils. The mat foundation should be constructed overlying reinforced fill with foundation drains and drainage in the bottom of the reinforced fill as outlined in Section 6.2 and 6.3. Frost depth at this site is 48-in below finished grade according to the Moffat County, Colorado Building Department. The

Dinosaur National Monument, Moffat County, CO non-frost-susceptible material used to construct the reinforced fill should extend to a minimum of 48-in below finished grade.

6.4.1 Modulus of Subgrade Reaction

The modulus of subgrade reaction is required to design a flexible mat foundation. The modulus of subgrade reaction, Ks, is the soil’s capacity to withstand pressure for a given displacement (Bowles, 1996). The modulus of subgrade reaction is calculated using the bearing capacity of the soil and the applied factor of safety, in Equation

1. The units for this value are kips/ft3. Theoretically, this equation estimates the pressure per square inch required to displace one inch of material.

𝐾𝐾𝑠𝑠 = 12(𝐹𝐹𝐹𝐹)𝑞𝑞𝑎𝑎 (Equation 1)

Where: FS = factor of safety qa = allowable bearing capacity

Using equation 1, and an estimated an allowable bearing capacity of the reinforced fill of 5,000 psf and a factor of safety of 3, the modulus for subgrade reaction for the mat foundation underlying the proposed Yampa District multi-operations facility is 180 kips/ft3.

Note: The allowable bearing pressure of shallow spread footings is based on allowable settlement as presented in Table 6-1, whereas the subgrade reaction modulus is calculated based on shear failure of the reinforced fill, not the underlying native soils, and does not represent an allowable bearing capacity to be used at this site regardless subgrade preparation.

Dinosaur National Monument, Moffat County, CO

Item Description

Colluvium Reinforced Fill

Bearing Layer Not recommended as a bearing layer Reinforced fill constructed per recommendations in this report

Soil Movement

Subject to potential settlement, collapse, and heave

Soil movement will depend on the thickness of the reinforced fill section selected. For a mat foundation, the differential settlement can be estimated at 0.75-in for total slab movement of up to 2-in (Bowles, 1996). This assumes the site is prepared according to the recommendations of this report.

Bearing Capacity1,2 Not recommended as a bearing layer 1,500 psf

Minimum Dead Load 800 psf

Frost Depth Moffat County code requires 48-inches below the ground surface. However, a mat foundation can be protected from frost using a non-frost-susceptible material as reinforced fill3

Ultimate Soil Friction tan(30°) = 0.58 – for the interface of cast-in-place concrete on structural fill

1. Soil parameters (i.e., inputs to the bearing capacity equation) were derived based on lab testing results and experience working with similar soil deposits.

2. Soil bearing capacity is dependent not only on the soil strength, but also the geometry of the foundation elements. The calculated bearing capacity assumes 2-ft wide strip footings placed a minimum of 4-ft bgs, the reinforced fill has been prepared as per this report. If footing size and depth differs from these assumptions, this office should be notified to evaluate the foundation configuration.

It is often the case that heavily loaded, isolated footings may be optimized (i.e., made smaller) using a larger bearing capacity, thereby reducing the quantity of concrete required. Please contact JG for an evaluation.

3. Non-frost-susceptible material is defined in ASCE 32-01 as material containing less than 6% by mass passing the #200 sieve. Non-frost-susceptible material should be used for the entirety of the reinforced will and extend to a minimum depth of 48 inches below the ground surface.

6.4.2 Void Form

A void form can be used to mitigate the effects of the expansive soils and bedrock at the site. The void form will need to be field fit to occupy the area above the shallow claystone bedrock on the northern end of the proposed building. The void form should be placed at the base of the reinforced fill. A minimum of 1-ft of over-excavated and recompacted native soils should remain beneath the void form.

6.5 Deep Foundation Elements

A foundation system comprising grade beams supported by deep foundation elements is a common method used to reduce the risk of future settlement of foundation elements. Deep foundation elements are typically installed through the problematic soils and into a competent, underlying soil or bedrock stratum that can withstand foundation loads. The design of deep foundation elements installed into an underlying, competent stratum requires in-depth knowledge and understanding of the underlying bearing stratum to determine the foundation element capacities. Several different deep foundation elements were reviewed and addressed when

Dinosaur National Monument, Moffat County, CO determining their feasibility to be used at the project site. Due to the varying bedrock conditions comprising both competent material and potentially expansive material, using the bedrock as a bearing stratum presented a substantial risk – if foundation elements were to be installed in expansive bedrock, the movement could be transferred from the bedrock to the foundation element, and into the foundation of the building causing damage.

One deep foundation system that was determined to be feasible was micropiles. Because of the inconsistent bedrock underlying the compressible colluvium, a micropile design utilizing friction between the grout and the colluvium only was analyzed. A preliminary micropile design indicated micropiles would need to be 28-feet in length to withstand anticipated foundation loads. In addition to the inordinate length, all of the micropiles would need to be installed in the same soil stratum to ensure uniform performance and reduce the risk of differential settlement. Due to the varying bedrock depth, as well as the varying bedrock composition, this would be difficult if not impossible to achieve. Due to the required length of the micropiles and differing bedrock conditions, micropiles are not recommended as a foundation system.

Design assumptions and micropile design methodology are detailed in Appendix E.

6.6 Earthwork

6.6.1 Site Preparation

Prior to the placement of any fill, concrete slabs, or foundation…