ODF NCD SANTIAM FACILITY

North Cascade District Headquarters 22965 North Fork Road SE

Lyons, Oregon 97358

PROJECT MANUAL

Bid Set

Project Number: 223294 October 15, 2025

Oregon Department of Forestry Building F, 200 State Street

Salem, Oregon 97310

720 NW Davis Suite 300 Portland, Oregon 97209

503.221.1121 503.221.2077

ODF NCD Santiam Facility Table of Contents: 00 0110 North Cascade District Headquarters Page 1

LRS Architects, Inc.

PROCUREMENT AND CONTRACTING REQUIREMENTS – By Owner Under Separate Cover

NOTE: This Contract is governed by the STATE OF OREGON GENERAL CONDITIONS FOR PUBLIC IMPROVEMENT CONTRACTS (“General Conditions”) dated January 1, 2012, as modified by the Supplemental General Conditions, which are Exhibit 4 to the Price Agreement. In the event of a conflict between this document and Exhibit 4, parties shall refer to General Conditions at Section A.3 Interpretation of Contract Documents for guidance.

INTRODUCTORY INFORMATION

00 0110 Table of Contents

AVAILABLE INFORMATION

00 3132 Geotechnical Data

00 3140 Energy Code Compliance Certificates

DIVISION 01 GENERAL REQUIREMENTS

01 1100 Summary of Work

01 2300 Alternates

01 2500 Substitution Procedures

Substitution Request Form

01 2600 Contract Modification Procedures

01 2900 Payment Procedures

01 3100 Project Management and Coordination

01 3300 Submittal Procedures

01 3573 Delegated Design Procedures

01 4200 Definitions and Reference Standards

01 4500 Quality Control

01 5000 Temporary Facilities and Controls

01 6000 Product Requirements

01 7329 Cutting and Patching

01 7400 Cleaning

01 7410 Construction Waste Management

01 7700 Closeout Procedures

01 9113 General Commissioning Requirements

DIVISION 02 EXISTING CONDITIONS

02 4100 Demolition

02 4113.13 Selective Demolition

02 4113.23 Utility Line Removal

02 5000 Site Remediation

02 6500 Underground Storage Tank Removal

DIVISION 03 CONCRETE

03 3000 Cast-In-Place Concrete

03 3511 Concrete Floor Finishes

DIVISION 05 METALS

North Cascade District Headquarters Page 2

05 5000 Metal Fabrications

DIVISION 06 WOOD, PLASTICS, AND COMPOSITES

06 1000 Rough Carpentry

06 1753 Shop-Fabricated Wood Trusses

06 2013 Exterior Finish Carpentry

06 4000 Architectural Woodwork

DIVISION 07 THERMAL AND MOISTURE PROTECTION

07 1900 Water Repellents

07 2100 Thermal Insulation

07 2810 Mechanically Attached Air-Water Barriers

07 4113 Metal Roof Panels

07 4646 Fiber Cement Siding

07 6200 Sheet Metal Flashing and Trim

07 6500 Self-Adhered Membrane Flashing

07 7200 Roof Accessories

07 9200 Joint Sealants

DIVISION 08 DOORS AND WINDOWS

08 1113 Hollow Metal Doors and Frames

08 1416 Flush Wood Doors

08 3613 Sectional Doors

08 4313 Aluminum-Framed Storefronts

08 5413 Fiberglass Windows

08 7100 Door Hardware

08 8000 Glazing

08 8300 Mirrors

08 9150 Louvers and Vents

DIVISION 09 FINISHES

09 2900 Gypsum Board

09 3000 Tiling

09 5100 Acoustical Ceilings

09 6513 Resilient Base and Accessories

09 6813 Tile Carpeting

09 8110 Acoustic Insulation and Sealant

09 9113 Exterior Painting

09 9123 Interior Painting

North Cascade District Headquarters Page 3

DIVISION 10 SPECIALTIES

10 1400 Signage

State of Oregon Department of Administrative Services Sign Ordering Workbook, Volume B

10 2113 Metal Toilet Compartments

10 2214 Chain Link Partitions

10 2610 Wall Protection

10 2613 Corner Guards

10 2813 Toilet Accessories

10 4400 Fire Protection Specialties

10 5113 Metal Lockers

DIVISION 11 EQUIPMENT

11 3013 Residential Appliances

DIVISION 12 FURNISHINGS

12 2400 Window Shades

12 3600 Countertops

DIVISION 21 FIRE SUPPRESSION – Delegated Design

21 0000 Fire Suppression Basic Requirements

21 0500 Common Work Results for Fire Suppression

21 1300 Fire Suppression Sprinkler systems

DIVISION 22 PLUMBING

22 0000 Plumbing Basic Requirements

22 0513 Common Motor Requirements for Plumbing Equipment

22 0519 Plumbing Devices

22 0523 General-Duty Valves for Plumbing Piping

22 0529 Hangers and Supports for Plumbing Piping and Equipment

22 0553 Identification for Plumbing Piping and Equipment

22 0700 Plumbing Insulation

22 0800 Commissioning of Plumbing

22 1000 Plumbing Piping

22 3000 Plumbing Equipment

22 4000 Plumbing Fixtures

North Cascade District Headquarters Page 4

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

23 0000 Heating, Ventilating, and Air-Conditioning (HVAC) Basic Requirements

23 0005 Heating, Ventilating and Air Conditioning Pre-Closeout Checklist

23 0529 Hangers and Supports for HVAC Piping, Ductwork and Equipment

23 0548 Vibration and Seismic Controls for HVAC Equipment

23 0553 Identification for HVAC Piping, Ductwork and Equipment

23 0593 Testing, Adjusting, and Balancing for HVAC

22 0700 HVAC Insulation

23 0800 Commissioning of HVAC

23 0933 Electric and Electronic Control System for HVAC

23 2113 HVAC Piping

23 3100 HVAC Ducts and Casings

23 3300 Air Ducts and Accessories

23 3400 HVAC Fans

23 3700 Air Outlets and Inlets

23 4000 HVAC Air Cleaning Devices

23 6201 Variable Refrigerant Flow Volume (VRF/VRV) Systems

23 7223 Packaged Air-to-Air Energy Recovery Units

23 8143 Air Source Heat Pumps

23 8200 Terminal Heat Transfer Equipment

DIVISION 26 ELECTRICAL

26 0000 Electrical Basic Requirements

26 0509 Equipment Wiring

26 0519 Low-Voltage Electrical Power Conductors and Cables

26 0526 Grounding and Bonding for Electrical Systems

26 0529 Hangers and Supports for Electrical Systems and Equipment

26 0533 Raceways

26 0534 Boxes

26 0543 Electrical Vaults and Underground Raceways

26 0553 Identification for Electrical Systems

26 0573 Electrical Distribution System Studies

26 0800 Commissioning of Electrical

26 0900 Contactors and Control Devices

26 0920 Lighting Relay Control Panel

26 0923 Occupancy and Vacancy Sensors

26 0924 Daylighting Controls

26 2413 Switchboards

26 2416 Panelboards

26 2713 Electrical Metering

26 2726 Wiring Devices

26 2800 Overcurrent Protective Devices

26 2816 Enclosed Switches and Circuit Breakers

26 3100 Photovoltaic Systems

26 3323 Central Battery Equipment

26 3600 Transfer Switches

26 3601 Generator Docking Station

26 4300 Surge Protective Devices

26 5100 Lighting

North Cascade District Headquarters Page 5

DIVISION 27 COMMUNICATIONS

27 0000 Communications Basic Requirements

27 0528 Pathways for Communication Systems

27 1100 Communication Equipment Rooms

27 1300 Communications Backbone Cabling

27 1500 Communications Horizontal Cabling

27 4116 Integrated Audio-Video Systems and Equipment

DIVISION 28 ELECTRONIC SAFETY AND SECURITY

28 0000 Electronic Safety and Security Basic Requirements

28 0800 Commissioning of Fire Alarm

28 1000 Access Control and Intrusion Detection

28 2300 Video Surveillance

28 4600 Fire Detection and Alarm

DIVISION 31 EARTHWORK

31 1100 Clearing and Grubbing

31 2300 Exavation and Fill Placement

31 2323.23 Compaction

31 2333 Trenching

31 2500 Erosion Control

31 8000 Control of Water

DIVISION 32 EXTERIOR IMPROVEMENTS

32 1123 Aggregate Base

32 1216 Asphalt Pavement

32 1613 Curbs and Gutters

32 1623 Sidewalks

32 1723.13 Pavement Markings

32 3113 Chain Link Fences and Gates

32 8400 Planting Irrigation

32 9115 Soil Preparation

32 9200 Turf and Grasses

32 9300 Plants

32 9310 Landscape Maintenance

DIVISION 33 UTILITIES

33 0563 Precast Concrete Meter Vault

33 1413 Public Water Utility Distribution Piping

33 1414 Locate Wire and Warning Tape

33 1419 Waterline Appurtenances

33 1420 Water Service Connections

33 4211 Storm Drain Piping and Fittings

33 4231 Area Drains and Inlets

END OF TABLE OF CONTENTS

ODF NCD Santiam Facility Geotechnical Data 00 3132 North Cascade District Headquarters Page 1

PART 1 GENERAL

1.1. GEOTECHNICAL DATA

A. A copy of a geotechnical report and Addendum Report No. 1, with respect to the building site are included herewith and are titled as follows:

1. "Geotechnical Engineering Services, Oregon Department of Forestry, North Cascade District Santiam Facility, Lyons, Oregon" dated October 17, 2024, and prepared by GeoEngineers, 4000 Kruse Way Place, Suite 200, Lake Oswego, Oregon 97035.

2. "Addendum Report No. 1, Stormwater Infiltration Evaluation, Oregon Department of Forestry, North Cascade District Santiam Facility, Lyons, Oregon" dated February 19, 2025, and prepared by GeoEngineers, 4000 Kruse Way Place, Suite 200, Lake Oswego, Oregon 97035.

B. This geotechnical report identifies properties of below grade conditions and recommendations for the design of foundation systems, but is not a warranty of subsurface conditions.

C. The recommendations described shall not be construed as a requirement of this Contract, unless specifically referenced in the Contract Documents. This document and its attachments are not part of the Contract Documents.

D. This report, by its nature, cannot reveal all conditions that exist on the site. Should subsurface conditions be found to vary substantially from this report, changes in the design and construction of foundations will be made, with resulting credits or expenditures to the Contract Sum accruing to the Owner.

PART 2PRODUCTS (NOT APPLICABLE)

PART 3 EXECUTION (NOT APPLICABLE)

END OF DOCUMENT

Geotechnical Engineering Services

North Cascade District Santiam Facility Lyons, Oregon for

October 17, 2024

4000 Kruse Way Place, Building 3, Suite 200 Lake Oswego, Oregon 97035

503.624.9274

Geotechnical Engineering Services

North Cascade District Santiam Facility

Lyons, Oregon

File No. 8276-004-00 October 17, 2024

Prepared for:

c/o LRS Architects, Inc.

720 NW Davis, Suite 300 Portland, Oregon 97209

Attention: Mary Fierros Bower

Prepared by:

GeoEngineers, Inc.

4000 Kruse Way Place, Building 3, Suite 200 Lake Oswego, Oregon 97035 503.624.9274

Kyle M. Smith, PE Senior Geotechnical Engineer

Dennis J. Thompson, PE Associate

KMS:DJT:atk

Disclaimer: Any electronic form, facsimile, or hard copy of the original document (email, text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record.

Oregon Department of Forestry | October 17, 2024 i

Table of Contents

1.0 Introduction

1.1 Project Description

1.2 Purpose and Scope

2.0 Field Explorations and Laboratory Testing

2.1 Field Explorations

2.2 Laboratory Testing

3.0 Site Description

3.1 site Geology

3.2 Surface Conditions

3.3 Subsurface Soil Conditions

3.4 Groundwater Conditions

4.0 Conclusions and Recommendations

4.1 Earthquake Engineering

4.1.1 2021 IBC Seismic Design Information

4.1.2 Liquefaction Potential

4.1.3 Ground Rupture/Lateral Spreading

4.1.4 Landslides

4.2 Foundation Support

4.2.1 Minimum Width and Depth Criteria

4.2.2 Allowable Bearing Pressure

4.2.3 Settlement

4.2.4 Lateral Resistance

4.2.5 Construction Considerations

4.3 Retaining Walls

4.3.1 Design Parameters

4.3.2 Wall Drainage

4.3.3 Other Considerations

4.4 Slab-on-Grade Floor

4.4.1 Subgrade Preparation

4.4.2 Design Parameters

4.5 Pavement Recommendations

4.5.1 Dynamic Cone Penetrometer (DCP) Field Testing and Resilient Modulus (MR)

4.5.2 Subgrade Preparation

4.5.3 New Hot Mix Asphalt Pavement

4.5.4 Portland Cement Concrete Pavement

4.5.5 Asphalt-Treated Base

Oregon Department of Forestry | October 17, 2024 ii

4.6 Site Preparation and Earthwork

4.6.1 Clearing, Stripping and Grubbing

4.6.2 Grading and Excavation

4.6.3 Cut and Fill Slopes

4.6.4 Foundations

4.6.5 Subgrade Preparation (Foundation Grade, Floor Slabs, Pavement and Hardscape) .. 12

4.6.6 Observation and Testing

4.6.7 Mitigation of Unsuitable Soil

4.6.8 Sedimentation and Erosion Control

4.6.9 Weather Considerations

4.7 Structural Fill and Compaction

4.7.1 Imported Select Structural Fill

4.7.2 Aggregate Base

4.7.3 Trench Backfill

4.7.4 Fill Placement and Compaction Criteria

4.8 Site Drainage and Groundwater Considerations

4.9 Stormwater Infiltration Considerations

4.10 Recommended Additional Geotechnical Services

5.0 Limitations

6.0 References

List of Figures Figure 1. Vicinity Map Figure 2. Site Plan Figure 3. Compaction Criteria for Trench Backfill

Appendices Appendix A. Field Explorations

Figure A-1. Key to Exploration Logs Figures A-2 through A-9. Test Pit Logs

Appendix B. Laboratory Testing Figures B-1 and B-2. Sieve Analysis Results Figures B-3 and B-4. Photos of Cobbles and Boulders

Appendix C. Report Limitations and Guidelines for Use

Oregon Department of Forestry | October 17, 2024 Page 1

1.0 Introduction

This report presents the results of our geotechnical engineering services for the Oregon Department of Forestry North Cascade District Office (NCD) Santiam Facility project at 22965 North Fork Road in Lyons, Oregon. The location of the site and general configuration of the proposed facility are shown in Figures 1 and 2, respectively.

1.1 PROJECT DESCRIPTION

The proposed Santiam Facility will consist of constructing approximately 12,000 square feet of new Forestry Buildings including a combined fire/shop building and a combined administration office/fitness building surrounding a centrally located courtyard. Each of the buildings are planned as single story with at grade foundations. Modifications to the existing surface parking lot are also planned. We understand that there is also the potential for a future expansion of the fire/shop building, although it is not part of the current study. A stormwater retention pond is planned in the southern portion of the site.

Information regarding final site layout and locations of buildings, grading plans and foundation loads were not provided at the time we prepared this report. Based on our understanding of the project, we anticipate excavating (cutting) or filling to achieve final site grades should be minor (generally less than about 5 feet).

Based on our experience, we anticipate that foundation loads will be moderate, less than about 5 to 8 kips per lineal feet (klf) for continuous (wall) footings and 200 to 400 kips for individual (column) loads.

The site currently consists of asphalt and gravel surfaced parking and drive areas with grass landscaping around the perimeter. The area is actively in use by the Oregon Department of Forestry. The former administration building at the south end of the site burned down during a fire that occurred in 2020.

1.2 PURPOSE AND SCOPE

The purpose of our services is to evaluate soil and groundwater conditions as a basis for developing design criteria for the geotechnical aspects of the Santiam Facility. Field explorations and laboratory testing were performed to identify and evaluate subsurface conditions at the site to develop engineering recommendations for use in design of the project.

Our services were performed in general accordance with our proposal dated March 8, 2024, and was authorized by LRS Architects on April 2, 2024.

2.0 Field Explorations and Laboratory Testing

2.1 FIELD EXPLORATIONS

Subsurface conditions were evaluated through a field exploration program that consisted of seven test pits and four dynamic cone penetrometer (DCP) tests. The explorations were completed within the vicinity of the planned building footprints using track-mounted excavator equipment subcontracted to GeoEngineers.

The approximate locations of the test pits and DCP tests are shown in Figure 2.

Oregon Department of Forestry | October 17, 2024 Page 2

The test pits, designated TP-1 through TP-7, were excavated to depths of about 6 to 8.5 feet. Locations of explorations were determined by reviewing foundation layout and by tape measuring to existing site features. Elevations at the exploration locations were estimated using Google Earth. The respective ground surface elevations are shown on the test pit logs in Appendix A and should be considered approximate.

Appendix A includes logs test pits (Figures A-2 through A-8) and details of the subsurface explorations performed.

2.2 LABORATORY TESTING

Soil samples obtained from the explorations were transported to our laboratory and evaluated to confirm or modify field classifications, as well as to evaluate engineering properties of the soil. Representative samples were selected for laboratory testing consisting of moisture content, percent passing the No. 200 sieve, and sieve analyses. The tests were performed in general accordance with test methods of the American Society for Testing and Materials (ASTM) or other applicable procedures. A brief discussion of the laboratory tests and test results is included in Appendix B.

3.0 Site Description

3.1 SITE GEOLOGY

Our review of the geologic map for the area indicates that the site is underlain by medium dense to dense terrace deposits at relatively shallow depths. The terrace deposits generally consist of mixed grained sediments including silt, sand and gravel with larger constituents up to boulder-size. The mixed grained sediments are commonly stratified. Water well logs in the site vicinity indicate that the sand and gravel formation is cemented from depths of about 30 to 50 feet. Shale and sandstone bedrock is present within the upper 100 feet in the area.

3.2 SURFACE CONDITIONS

The site is located north of Highway 22 (North Santiam Highway) and northwest of North Fork Road. The site slopes down north to south from approximate Elevation 690 feet to Elevation 685 feet. The site currently consists of asphalt and gravel surfaced parking and drive areas with grass landscaping around the perimeter. Forestry maintenance buildings are present in the northern area of the site.

3.3 SUBSURFACE SOIL CONDITIONS

At the locations of test pits TP-1, TP-2, TP-4 and TP-6, surface conditions included a combination of asphalt concrete and/or crush rock base course that extended to depths ranging between approximately 4 to 10 inches. At the location of test pit TP-7, we initiated the test pit in grass surfacing and encountered approximately 3 inches of sod. Underlying the asphalt concrete, crushed rock base course and sod, where present, the soils encountered in the explorations consisted of the following:

■ Fill/re-worked terrace deposits: Approximately 2 feet of fill and/or re-worked terrace deposits were observed in test pit TP-3. Burned wood was observed 2 feet below current site grades and is likely a product of the fire that damaged the previous building and the subsequent re-grading of the site after the fire.

Oregon Department of Forestry | October 17, 2024 Page 3

■ Terrace deposits: Terrace deposits were encountered in all test pits completed onsite. The terrace deposits generally consist of an upper layer of silty sand/silty gravel with cobbles, that graded to cobbles mixed with gravel with variable silt and sand content. Boulders are also present in the terrace deposits. Terrace deposits were encountered in a generally medium dense to dense condition and extend to the maximum depths explored. In general, the upper approximate 3 feet contains a higher fines content. The percent fines were observed to decrease with depth. Caving soils were observed during the excavation of each test pit at depths of 2 to 4 feet, although the caving generally did not begin until the excavation was below about 6 to 8 feet.

3.4 GROUNDWATER CONDITIONS

Groundwater was not observed in the test pits excavated onsite. The site is on the order of 50 feet above the surface elevation of the Santiam River located approximately 150 feet down slope from the site. Based on our review of water well reports completed in the vicinity of the site and available through the Oregon Water Resources Department, groundwater in the area appears to be at least 50 feet below site grades.

Localized perched groundwater zones may exist within the terrace deposits and is common for perched groundwater to be present near contacts where soil that is more permeable overlies soil that is less permeable (e.g. sand over silt), which can also be encountered within the terrace deposits. Site grading, time of year and presence of nearby underground structures can also affect presence of seepage and therefore, the quantity and location of perched groundwater.

4.0 Conclusions and Recommendations

Based on the results of our site exploration, laboratory testing and engineering analyses, it is our opinion site conditions are generally favorable for design and construction of the proposed development as described in the Introduction section of this report. The following provides a brief summary of geotechnical considerations for the proposed project:

■ Onsite soils generally consist of native terrace deposits, which contain gravel, cobbles and boulders.

The site is generally suitable for support of shallow spread foundations, floor slabs and pavement.

Loose terrace deposits, encountered at foundation grade, should be removed from below proposed foundations and replaced with properly compacted on-site soil or imported structural fill.

■ The site is best classified as Site Class C for structural and seismic design, in accordance with

2021 IBC.

■ We recommend designing foundations for an allowable bearing pressure of 4,500 pounds per square foot (psf).

■ Conventional slab on grade is appropriate for this site. We recommend that the concrete slab be designed using a modulus of subgrade reaction of 200 pounds per cubic inch (pci).

■ Surficial site soil is moisture sensitive and will be difficult to adequately work and compact if moisture contents are not within about 2 to 4 percent of optimum at the time earthwork is performed.

Oregon Department of Forestry | October 17, 2024 Page 4

■ Site soil contains a significant amount of cobbles and boulders which are more prominent at depth. We anticipate that scrapers might not be suitable for excavation at the site and that other typical excavation equipment such as dozers, backhoes and excavators with toothed buckets could be required to excavate site soil efficiently. Additionally, screening of on-site excavated soil will be required before excavated site soil is suitable for reuse as structural fill.

These and other considerations are discussed in the following sections of this report. This report should be read in its entirety to fully understand geotechnical design and construction considerations and recommendations.

4.1 EARTHQUAKE ENGINEERING

We evaluated the site for seismic hazards including liquefaction, lateral spreading, fault rupture and earthquake induced landsliding. Our evaluation indicates that the site does not have liquefiable soils present and therefore also has no risk of liquefaction induced lateral spreading. In addition, the site has a low risk of fault rupture and earthquake induced landsliding.

4.1.1 2021 IBC Seismic Design Information

For the site, we recommend the International Building Code (IBC) parameters for Site Class C, mapped risk-targeted maximum-considered earthquake (MCER) spectral response acceleration at short period (Ss), mapped MCER spectral response acceleration at 1-second period (S1), short period site coefficient (Fa), long period site coefficient (Fv), design spectral acceleration at 0.2-second period (SDS) and the design spectral acceleration at 1.0-second period (SD1). Table1 summarizes recommended values for these parameters.

TABLE 1. 2021 IBC SEISMIC PARAMETERS

IBC PARAMETER1 VALUE

Site Class C

Mapped MCER Spectral Response Acceleration at Short Period, Ss (g) 0.654

Mapped MCER Spectral Response Acceleration at 1-second period, S1 (g) 0.331

Short Period Site Coefficient, Fa 1.238

Long Period Site Coefficient, Fv 1.5

Design Spectral Acceleration at 0.2-second period, SDS (g) 0.54

Design Spectral Acceleration at 1.0-second period, SD1 (g) 0.331

Notes:

1 Parameters developed based on latitude 44.7915 and longitude -122.6011 using the Applied Technology Council (ATC) Hazards online tool (https://hazards.atcouncil.org/).

4.1.2 Liquefaction Potential

Liquefaction is a phenomenon where soils experience a rapid loss of internal strength as a consequence of strong ground shaking. Ground settlement, lateral spreading and/or sand boils may result from soil liquefaction. Structures supported on liquefied soils could suffer foundation settlement or lateral movement that could be severely damaging to the structures.

Oregon Department of Forestry | October 17, 2024 Page 5

Conditions favorable to liquefaction occur in loose to medium dense, clean to moderately silty sand that is below the groundwater level. Based on our review of site conditions, understanding of geology in the area and review of groundwater information, these conditions are not present at the site; therefore, it is our opinion that potentially liquefiable soils are not present below the site.

4.1.3 Ground Rupture/Lateral Spreading

Ground rupture from lateral spreading is associated with liquefaction. Lateral spreading involves lateral displacements of large volumes of liquefied soil and can occur on near-level ground as blocks of surface soils displace relative to adjacent blocks. In our opinion, ground rupture resulting from lateral spreading at the site is unlikely because potentially liquefiable soils are not present at the site as discussed above.

4.1.4 Landslides

Because of the site geology, topography and groundwater conditions, it is our opinion that landsliding as a result of strong ground shaking is unlikely at this site.

4.2 FOUNDATION SUPPORT

The following design parameters for shallow spread foundations are based on the condition that foundation preparation recommendations presented in following sections of this report are accurately relayed to the earthwork and general contractors in the bid documents and are followed during construction. Specifically, foundations should bear on properly prepared terrace deposits, or on structural fill overlying these on-site soil units. Existing fill or re-worked terrace deposits should be removed and replaced with approved structural fill below foundations.

4.2.1 Minimum Width and Depth Criteria

We recommend individual (column) and continuous (wall) spread footings be designed with minimum dimensions of 24 and 16 inches, respectively. We further recommend foundations (bottom of footing) be constructed at a minimum depth of at least 24 inches below the nearest adjacent exterior finished grade to protect against frost heave. Interior foundations within heated portions of buildings may be constructed at a minimum depth of at least 12 inches below interior grade.

4.2.2 Allowable Bearing Pressure

Determination of allowable bearing pressures for shallow spread foundation design includes considerations for both bearing capacity (ability of supporting soil to resist applied foundation loads without undergoing shear failure) and serviceability (ability of supporting soil to resist applied foundation loads while staying within allowable parameters for total and differential settlement). Bearing capacity is a function of several parameters including, but not limited to, shear strength and unit weight of supporting soil, depth of footing embedment, footing dimensions (length and width); and depth to the groundwater table in relation to the footing depth and dimensions. Serviceability (foundation settlement) is primarily a function of the compressibility of the soil within the zone of significant stress influence below the footing (the zone of stress influence typically extends to a depth of about 2 to 4 times the footing width), and the magnitude of the foundation load. Based on the results of our analysis, we recommend an allowable bearing pressure of 4,500 pounds per square foot (psf).

Oregon Department of Forestry | October 17, 2024 Page 6

The allowable bearing pressure is net allowable bearing pressures for the total of dead plus real live loads, and exclusive of the weight of backfill above the foundation. The allowable bearing pressure may be increased by one-third to account for short-term loads, such as from wind or seismic conditions.

4.2.3 Settlement

Based on the assumed column and wall loads noted previously in this report, we estimate that settlement of footings, designed and constructed as recommended in this report, should be less than about 1 inch.

Differential settlement between columns or along approximately 50 feet of continuous wall footing should be less than about ½ inch. Settlement should occur essentially as loads are applied. Post-construction settlement should be minor. Loose soil not removed from footing excavations, or disturbance of soil at foundation grade during construction, could result in larger settlements than estimated. We should be contacted to re-evaluate our settlement estimates if loads greater than indicated in the Introduction section of this report are anticipated.

4.2.4 Lateral Resistance

The soil pressure available to resist lateral foundation loads is a function of the frictional resistance against the foundation base and the passive resistance, which can develop on the face of below-grade elements of the structure as those elements move horizontally into the soil. For foundations bearing in soil prepared as recommended, the allowable frictional resistance may be computed using a coefficient of friction of 0.40 applied to vertical dead-load forces for the contact between concrete and properly prepared site gravel or structural fill.

The allowable passive resistance on the face of footings, grade beams or other embedded foundation elements may be computed using an equivalent fluid density of 300 pounds per cubic foot (pcf), triangular distribution, for on-site soil or structural fill. Mobilization of passive resistance will require lateral foundation movement into the soil. The magnitude of lateral movement required to mobilize passive resistance depends on foundation embedment. We estimate that lateral movement required to mobilize the allowable passive resistance could be about 0.02D (where D is the depth of embedment of the foundation element).

For footings embedded 2 feet below exterior grade, this equates to a lateral movement of about ½ inch.

The above values include a factor of safety of about 1.5 and assumes that backfill placed against embedded elements is compacted in accordance with the following sections of this report.

4.2.5 Construction Considerations

Immediately prior to placing concrete, all debris and loose soils that accumulated in the footing excavations during forming and steel placement must be removed. Debris or loose soils not removed from the footing excavations will result in increased settlement.

4.3 RETAINING WALLS

The following recommendations should be used for the design of below-grade walls that are intended to act as retaining walls and for other retaining structures that are used to achieve grade changes.

Oregon Department of Forestry | October 17, 2024 Page 7

4.3.1 Design Parameters

Lateral earth pressures for design of below-grade cast-in-place walls and retaining structures should be evaluated using an equivalent fluid density of 35 pcf provided that the walls will not be restrained against rotation when backfill is placed (active condition). If the walls are restrained from rotation (at-rest condition), we recommend using an equivalent fluid density of 55 pcf. Walls are assumed to be restrained if top movement during backfilling is less than H/1000, where H is the wall height. These lateral soil pressures assume that the ground surface behind the wall is horizontal and that the cast-in-place walls are backfilled with structural fill. For unrestrained walls with backfill sloping up at 2H:1V, the design lateral earth pressure should be increased to 55 pcf, while restrained walls with a 2H:1V sloping backfill should be designed using an equivalent fluid density of 75 pcf. These lateral soil pressures do not include the effects of surcharges such as floor loads, traffic loads or other surface loading. Surcharge effects should be included, as appropriate. We can assist with additional pressure loading design once loading magnitude and location has been determined. Below-grade walls for buildings should also include seismic earth pressures. Seismic earth pressures should be included as a rectangular distribution determined using 7H in psf, where H is the wall height.

If vehicles can approach the tops of exterior walls to within half the height of the wall, a traffic surcharge should be added to the wall pressure. For automobile parking areas, we recommend a uniform lateral traffic surcharge of 35 psf behind the wall. For delivery truck parking areas and access driveway areas, we recommend a uniform lateral traffic surcharge of 70 psf behind the wall. These recommendations are intended only for walls with positive drainage provided behind the walls.

The values for soil bearing, frictional resistance and passive resistance presented above for foundation design are applicable to retaining wall design. Walls located in level ground areas should be founded at a depth of 18 inches below the adjacent grade.

4.3.2 Wall Drainage

To reduce the potential for hydrostatic water pressure buildup behind the retaining walls, we recommend that the walls be provided with wall drainage. Wall drainage can be achieved by using free draining material with perforated pipes to discharge the collected water. The zone of free-draining material should be 2 feet wide and should extend from the base of the wall to within 2 feet of the ground surface. The free draining material should be covered with 1 foot of less permeable material, such as the on-site terrace deposits, with fines content greater than 15 percent, underlain by a geotextile separator such as Mirafi 140N. We recommend against using flexible tubing for wall drainage pipe. The footing drain recommended above can be incorporated into the bottom of the wall drainage zone and used for this purpose.

The pipes should be laid with minimum slopes of one-quarter percent (if possible) and discharge into the stormwater collection system to convey the water off site, or to other appropriate discharge points. The pipe installations should include a cleanout riser with cover located at the upper end of each pipe run. The cleanouts could be placed in flush mounted access boxes. Roof downspouts must not discharge into the perforated pipes intended for providing wall back drainage.

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4.3.3 Other Considerations

Exterior retaining systems used to achieve grade transitions or for landscaping, can be constructed using traditional structural systems such as reinforced concrete, concrete masonry units (CMU) blocks, or rockeries. Alternatively, retaining walls can consist of mechanically stabilized earth (MSE) walls, which may be an economical alternative to traditional retaining wall systems. We can provide additional design recommendations for MSE walls, if requested.

4.4 SLAB-ON-GRADE FLOOR

4.4.1 Subgrade Preparation

We recommend that concrete slabs-on-grade be constructed on a gravel layer to provide uniform support and drainage, and to act as a capillary break. We expect that slab-on-grade floors can be supported on medium dense to dense native terrace deposit soils encountered in our explorations, or on properly compacted structural fill extending down to these materials. Prior to placing the gravel layer, the subgrade should be proof-rolled. The exposed subgrade should be evaluated during construction and compacted to a firm and unyielding condition. Unsuitable soils should be removed and replaced with structural fill where needed.

4.4.2 Design Parameters

A 6-inch-thick capillary break layer of 1-inch minus clean crushed gravel with negligible sand and silt should be placed to provide uniform support and form a capillary break beneath the slab. The capillary break material should be kept free from fine-grained soil contamination and deleterious materials; as such, we do not recommend the capillary break material be used as a traffic layer for protection during site development. In general, the capillary break material should be placed shortly before the slab is ready to be poured.

For slabs designed as a beam on an elastic foundation, a modulus of subgrade reaction of 200 pounds per cubic inch (pci) may be used for subgrade soils prepared as recommended above. This value assumes the slabs are bearing directly on structural fill placed over medium dense to dense native terrace deposits and will be evaluated during construction.

If water vapor migration through the slabs is objectionable, the capillary break gravel layer should be covered with heavy plastic sheeting at least 10-mil thick to act as a vapor retarder. This will be desirable where the slabs are in occupied spaces or will be surfaced with tile or will be carpeted. It may also be prudent to apply a sealer to the slab to further retard the migration of moisture through the floor. The contractor should be made responsible for maintaining the integrity of the vapor barrier during construction.

Additional water proofing measures that may be needed should be evaluated during design.

4.5 PAVEMENT RECOMMENDATIONS

4.5.1 Dynamic Cone Penetrometer (DCP) Field Testing and Resilient Modulus (MR)

We conducted four DCP tests in general accordance with ASTM D 6951 to estimate the subgrade resilient modulus (MR) at each test location as shown in Figure 2. We recorded penetration depth of the cone versus hammer blow count and terminated testing at depths of approximately 36 inches below the existing ground surface.

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We plotted depth of penetration versus blow count and visually assessed regions where slopes of the data were relatively constant using equation and procedures presented in the ODOT Pavement Design Guide to estimate the moduli using a conversion coefficient, Cf = 0.35. Table 3 lists our estimate of the subgrade resilient modulus at each test location based on data obtained in the upper 2 feet of terrace deposits. Field data are summarized in Figures A-9 through A-12.

TABLE 2. ESTIMATED SUBGRADE RESILIENT MODULI BASED ON DCP TESTING

BORING NUMBER ESTIMATED RESILIENT MODULUS (PSI)

DCP-1 4,500

DCP-2 3,900

DCP-3 5,300

DCP-4 6,800

4.5.2 Subgrade Preparation

We recommend the subgrade soils in new pavement areas be prepared and evaluated as described in Section 4.6. All new pavement and hardscape areas should be supported on subgrade soils that have been proof rolled or probed. If the exposed subgrade soils are loose or soft, it may be necessary to excavate localized areas and replace them with structural fill or gravel base course. Pavement subgrade conditions should be observed during construction and prior to placing the subbase materials in order to evaluate the presence of zones of unsuitable subgrade soils and the need for over-excavation and replacement of these zones.

4.5.3 New Hot Mix Asphalt Pavement

In light-duty pavement areas (e.g., automobile parking), we recommend a pavement section consisting of at least 3 inches of hot-mix asphalt (HMA) over 4 inches of densely compacted aggregate base.

In heavy-duty pavement areas (such as driveways, truck traffic lanes, materials delivery), we recommend a pavement section consisting of at least 4 inches HMA over 6 inches of densely compacted aggregate base.

The aggregate base should meet the gradation specifications in report section 4.7.2 and should be compacted to at least 95 percent of the MDD obtained based on ASTM D 1557 test procedures.

We recommend that proof rolling of the subgrade and compacted aggregate base be observed by a representative from our firm prior to paving. Soft or yielding zones observed during proof rolling may require over-excavation and replacement with compacted structural fill.

The hot mix asphalt (HMA) should conform to Section 00745 of the most current edition of the Oregon Department of Transportation (ODOT) Standard Specifications for Highway Construction. The job mix formula should meet the requirements for a ½-inch Dense Graded Level 2 Mix. The HMA should be PG 64-22 grade meeting the ODOT Standard Specifications for Asphalt Materials. For ½-inch Dense Graded Level 2 HMA Mix, the lift thicknesses should be at least 2 inches but no more than 3.5 inches.

The pavement sections recommended above are based on our experience. Thicker asphalt sections may be needed based on the actual traffic data, truck loads, and intended use. All paved and landscaped areas should be graded so that surface drainage is directed to appropriate catch basins.

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4.5.4 Portland Cement Concrete Pavement

Portland cement concrete (PCC) sections may be considered for areas where concentrated heavy loads may occur. We recommend that these pavements consist of at least 6 inches of PCC over 6 inches of aggregate base. A thicker concrete section may be needed based on the actual load data for use of the area. If the concrete pavement will have doweled joints, we recommend that the concrete thickness be increased by an amount equal to the diameter of the dowels. The base course should be compacted to at least 95 percent of the MDD.

A jointing plan should be provided in the project plans showing construction joints, and transverse and longitudinal joints to control cracking consistent with American Concrete Pavement Association (ACPA) recommendations. Longitudinal joints typically coincide with lane widths and transverse joints are generally relatively equally spaced and close to the same spacing as longitudinal joints so that panels are relatively square. All panel joints should be doweled together in accordance with ODOT Standard Detail DET1600 and DET1602, and ACPA recommendations.

We recommend PCC pavements incorporate construction joints and/or crack control joints spaced at maximum distances of 12 feet apart, center-to-center, in both the longitudinal and transverse directions.

Crack control joints may be created by placing an insert or groove into the fresh concrete surface during finishing, or by saw cutting the concrete after it has initially set-up. We recommend the depth of the crack control joints be approximately one fourth the thickness of the concrete; or about 1½ inches deep for the recommended concrete thickness of 6 inches. We also recommend the crack control joints be sealed with an appropriate sealant to help restrict water infiltration into the joints.

4.5.5 Asphalt-Treated Base

If pavements are constructed during the wet seasons, consideration may be given to covering the areas to be paved with asphalt-treated base (ATB) for protection. Light-duty pavement areas should be surfaced with 3 inches of ATB, and heavy-duty pavement areas should be surfaced with 6 inches of ATB. Prior to placement of the final pavement sections, we recommend the ATB surface be evaluated and areas of ATB pavement failure be removed, and the subgrade repaired. If ATB is used and is serviceable when final pavements are constructed, the aggregate base can be eliminated, and the design PCC or asphalt concrete pavement thickness can be placed directly over the ATB.

4.6 SITE PREPARATION AND EARTHWORK

4.6.1 Clearing, Stripping and Grubbing

We envision initial site preparation and earthwork operations will include stripping and grubbing of topsoil and other vegetation at the site. Based on the results of our explorations, we anticipate the required stripping depths to remove topsoil should be on the order of about 6 inches. However, greater stripping depths might be required to remove localized zones of loose soil or soil with more than about 15 percent organic matter (by volume) that could be present in areas of the site that were not explored.

We further anticipate existing trees located in improvement areas will be removed during clearing. Stumps, root wads and roots greater than ½-inch-diameter should be thoroughly grubbed. Large stumps might require significant excavation to remove roots near the ground surface. The excavations to remove stumps and large root wads should be backfilled with structural fill compacted as recommended in a following section. Stumps, root wads, grubbed roots and other organic materials should be properly disposed off site.

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4.6.2 Grading and Excavation

We anticipate some cutting and filling will be required to establish proposed foundation grades, floor slab, pavement and exterior hardscape subgrades, and for installation of utilities. In our opinion, site soil can be excavated using conventional excavating equipment and procedures, such as backhoes, excavators and dozers. As indicated previously, site soil contains a significant amount of cobbles and boulders.

The earthwork contractor should consider the presence of these oversized materials when selecting earth moving equipment for the site.

Site soil, particularly the surficial silty sand and silty gravel soils, is moisture sensitive and will be difficult to work or compact if moisture contents are greater or less than the optimum moisture content by about 2 to 4 percentage points at the time of earthwork. When the moisture content of the soil is more than a few percent above the optimum moisture content, the soil could become muddy and unstable. Operation of equipment on such unstable soil without causing disturbance will be difficult, and it will be difficult or impossible to meet the required compaction criteria. Disturbance of near-surface soil should be expected if earthwork is performed during periods of wet weather. We recommend scheduling site preparation and earthwork activities during extended periods of dry weather when the soil should: (1) be less susceptible to disturbance; (2) provide better support for construction equipment; and (3) be more likely to meet the required compaction criteria.

If earthwork activities cause excessive subgrade disturbance after stripping, removal of the disturbed soil and moisture-conditioning such as scarifying or windrowing and waiting for the soil to dry, mixing with drier or less moisture sensitive soil, or replacement with structural fill might be necessary. Disturbance to a greater depth should be expected if site preparation work is conducted during periods of wet weather when the moisture content of the site soil could exceed optimum. All excavations should be backfilled with compacted structural fill.

4.6.3 Cut and Fill Slopes

In our opinion, excavations in the on-site soil are susceptible to sloughing and caving. Excavations deeper than 4 feet should be shored or sloped at stable inclinations if workers are required to enter such excavations. Shoring for excavations must conform to provisions of Occupational Safety and Health Administration (OSHA) and state regulations.

In our opinion, site soil classifies as OSHA Type C for excavation purposes. The maximum allowable temporary slope for Type C soil is 1.5H:1V (horizontal:vertical) for simple excavations less than 20 feet deep.

Temporary cut slope guidance assumes that all surface loads are kept a minimum distance of at least one-half the depth of the cut away from the top of the slope. Flatter slopes will be necessary if surface loads are imposed above the cuts a distance equal to or less than one-half the depth of the cut. It is the contractor’s responsibility to monitor and adjust the inclination of temporary excavated slopes and assure site safety during the proposed construction.

Alternatively, temporary shoring should be installed if space constraints limit the depth and/or inclination of cut slopes. Regardless of the soil type encountered in the excavation, shoring, trench boxes or sloped sidewalls will be required under OSHA regulations, as applicable.

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While this report describes certain approaches to excavation, the contract documents should specify that the contractor is responsible for selecting excavation methods, monitoring the excavations for safety, reducing temporary slope inclinations to improve stability and providing shoring, as required, to protect personnel.

Permanent cut and fill slopes should be sloped at an inclination no steeper than 2H:1V. Flatter slopes might be required for stormwater swales in order to meet criteria in the SRSM. Permanent cut and fill slopes should be seeded or sodded as soon as practical following construction to reduce the potential for erosion.

Some sloughing and erosion should be expected until vegetation matures.

4.6.4 Foundations

We recommend that shallow spread foundations be supported by either:

■ Properly prepared on-site terrace deposits; or

■ Structural fill overlying prepared on-site terrace deposits.

If the fill soil or disturbed layers of terrace deposits are present at foundation grade, the soil should be excavated to expose firm and undisturbed natural terrace deposit unit, and the excavation should be backfilled with structural fill. If overexcavation below foundation grade is required, the excavation should extend laterally beyond the foundation perimeter a distance equal to at least one-half the depth of excavation below the bottom of the footing.

4.6.5 Subgrade Preparation (Foundation Grade, Floor Slabs, Pavement and Hardscape)

After initial stripping and excavation activities are complete and before placing structural fill, the upper 12 inches of soil at working subgrade should be moisture-conditioned (as necessary) to within 2 to 4 percentage points of optimum moisture content and compacted to the minimum density requirements based on the ASTM International (ASTM) D 1557 laboratory test procedure (modified proctor) as listed below:

■ Soil at foundation grade in cut areas or working subgrade in overexcavation or fill areas: at least 95 percent of maximum dry density (MDD).

■ Soil at working subgrade more than 2 feet below finished subgrade in pavement and hardscape areas:

at least 90 percent of MDD.

■ Soil at working subgrade in pavement and hardscape areas at 2 feet or less below final subgrade: at least 95 percent of MDD.

■ Soil below floor slabs: at least 95 percent of MDD based on ASTM D 1557.

Where subgrade soil is too granular to test, alternative performance or method specifications might be required. Alternative criteria should be evaluated by the geotechnical engineer at the time of earthwork.

Care should be taken by the earthwork contractor not to compact soil exposed at working subgrade at the bottom of stormwater swales. Subgrade soil at the bottom of stormwater swales that is inadvertently compacted should be scarified and loosened to re-establish pre-existing hydraulic conductivity before placing treatment topsoil.

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