Attachment D_Geotechnical Report.pdf

Geotechnical Investigation

Toledo State Airport Taxiway and Apron Rehabilitation

Toledo, Oregon

Prepared for:

Century West Engineering Bend, Oregon

January 27, 2022

Foundation Engineering, Inc.

Professional Geotechnical Services

Professional Geotechnical Services

820 NW Cornell Avenue • Corvallis, Oregon 97330 • 541-757-7645 7587 SW Cirrus Drive, Bldg 24 • Beaverton, Oregon 97008 • 503-643-1541

Mark Hagedorn, P.E. January 27, 2022 Century West Engineering 1020 SW Emkay Drive, Suite 100 Bend, Oregon 97702

Toledo State Airport Project No.: 2211103 Taxiway and Apron Rehabilitation Geotechnical Investigation Toledo, Oregon

Dear Mr. Hagedorn:

We have completed the requested geotechnical investigation for the above-referenced project. Our report includes a description of our work, a discussion of the site conditions, and a summary of the field and laboratory testing. Geotechnical recommendations for the proposed pavement improvements are also included.

Construction recommendations refer to sections in the Oregon Standard Specifications for Construction (ODOT, 2021)

There are numerous values in geotechnical investigations that are approximate, including calculated values, measured lengths, soil layer depths and elevations, and strength measurements. For brevity, the symbol “±” is used throughout this report to represent the words approximate or approximately when discussing approximate values.

It has been a pleasure assisting you with this phase of your project. Please do not hesitate to contact us if you have any questions or if you require further assistance.

Sincerely, FOUNDATION ENGINEERING, INC.

Matthew D. Mason, P.E., G.E. David L. Running, P.E., G.E.

Project Engineer Senior Geotechnical Engineer

MDM/DLR

enclosures

Toledo State Airport – Taxiway and Apron Rehabilitation January 27, 2022 Geotechnical Investigation Project No.: 2211103 Toledo, Oregon 1 Century West Engineering

GEOTECHNICAL INVESTIGATION

TOLEDO STATE AIRPORT

TAXIWAY AND APRON REHABILITATION

TOLEDO, OREGON

BACKGROUND

Toledo State Airport is planning improvements at the airport that include rehabilitating the apron, the north taxiway, and a portion of the south taxiway. Paving of the existing gravel access road is also planned. The existing apron pavement has deteriorated to the consistency of fine gravel at most locations. In some places, especially the north end of the planned improvements, the pavement is absent, and the ground surface is surfaced with sand or short grass. Full-depth reconstruction/new pavements are planned for the improvements. The airport location is shown in Figure 1A (Appendix A). An aerial photo showing the site layout and proposed improvements is included in Figure 2A (Appendix A).

Century West Engineering (CWE) is the prime engineering consultant for the project and will provide pavement and civil design services. Foundation Engineering was retained by CWE to perform a subsurface investigation, conduct field and laboratory testing, and provide recommendations for subgrade preparation and pavement design parameters.

FIELD EXPLORATION

Nine borings (BH-1 through BH-9) were drilled within the proposed improvement areas on November 30, 2021, to evaluate the subsurface conditions. BH-1 was located on the south taxiway, BH-2 was located on the north taxiway, BH-3 through BH-8 were located within the apron improvement area, and BH-9 was located on the gravel access road. The approximate boring locations are shown on Figure 2A.

BH-1 and BH-2 were drilled through the existing pavement. A 5-inch diameter core drill was used to extend the exploration through the asphaltic concrete pavement (ACP). After removing the ACP, the base materials and subgrade were excavated using a 4-inch diameter solid-stem auger. BH-3 through BH-9 were drilled using the solid-stem auger. Drilling in each of the borings extended to a depth of 5 feet.

The borings were logged to identify the subgrade conditions. The logs are included in Appendix B. Dynamic Cone Penetrometer (DCP) testing was performed on the subgrade at most locations. The DCP testing is described in a subsequent section of this report.

Upon completion, the borings were backfilled with gravel or sand and that was placed and tamped in thin lifts. BH-1 and BH-2 were capped with ACP cold patch to match the adjacent pavement.

Toledo, Oregon 2 Century West Engineering

DISCUSSION OF SUBSURFACE CONDITIONS

The following sections provide a summary of the subsurface conditions encountered in the borings. More specific details are provided on the logs (Appendix B). Photos of the pavement cores are also provided in Appendix B. Important information about the boring logs and definitions of symbols and descriptive terms are provided in the Symbol Key and the Soil Descriptions and Common Terms Key included in Appendix B.

Pavement

Drilling in the taxiways encountered 2 inches of ACP at the south taxiway and 2¼ inches of ACP at the north taxiway. No base rock was encountered beneath the

ACP.

Drilling within the apron at BH-3 encountered a 1 inch of slurry seal at the surface.

No base rock was encountered beneath the slurry seal. It appears the entire apron was previously covered with a thin layer of slurry seal. However, this material is not very durable, and it appears to have deteriorated to the consistency of a fine gravel over time.

Subgrade

Medium dense sand with variable amounts of silt was encountered beneath the ACP and at the ground surface where there was no ACP. The sand represents fill that was previously used to raise the site above the low-lying wetlands adjacent to the Yaquina River. The sand extends to depths of ±2.5 to 4.5 feet. The sand is covered with ±6 inches of organic silt in the northern portion of the apron (BH-7 and BH-8) and with ±6 inches of crushed rock along the access road (BH-9). In each of the borings, soft, medium plasticity clayey silt with some organics extends below the sand to ±5 feet (the maximum depths of the borings).

Groundwater

Rapid seepage was encountered in the sand at depths ranging from ±4 to 18 inches.

The observed infiltration appears to be from surface runoff that collected in the sand fill and perched on the underlying low permeable clayey silt. Immediately north of the apron, water was observed at the surface of the low-lying wetlands at ±2½ to 3½ feet below the apron elevation. This depth likely represents the static ground water level at the time of the investigation and is expected to closely match the water level in the Yaquina River adjacent to the airport. Relatively shallow groundwater levels are anticipated year-round at the site due to it low-lying terrain and proximity to the river.

Toledo, Oregon 3 Century West Engineering

FIELD AND LABORATORY TESTING

DCP Testing

Dynamic Cone Penetrometer (DCP) testing was completed on the subgrade in all the borings except for BH-8. The DCP test consists of driving the cone of the DCP apparatus into the soil and recording the penetration versus blow count (mm/blow) as the DCP value.

The 2021 FAA Airport Pavement Design and Evaluation Circular (AC 150/5320-6G) provides several possible correlations for estimating in-situ subgrade elastic modulus

(E) or California Bearing Ratio (CBR) values from DCP test results. The various correlations rely, in part, on soil classification and expected range of CBR values. The Oregon Department of Transportation (ODOT) Pavement Design Guide (2019) also provides a correlation for using DCP results to calculate resilient modulus (MR) values.

For FAA pavement design, the subgrade elastic modulus (E) is synonymous with MR.

The ODOT correlation equation is less sensitive to variations in DCP blow count and ODOT recommends using their correlation for Oregon transportation projects. The DCP test results and correlated in-situ MR values based on ODOT guidelines are summarized in Table 1C (Appendix C).

In-situ MR values ranging from ±4,640 to 7,299 psi were calculated for the sandy subgrade extending ±2.5 to 4.5 feet below the ground surface. The FAA Pavement Advisory (AC No. 150/5320-6G) recommends calculating E (or MR) for the subgrade based on the following correlation with laboratory CBR tests:

E = 1500 x CBR where E is in units of psi.

Using the above equation and in-situ E values calculated based on the DCP results, we back-calculated in-situ CBR values ranging from ±3.1 to 4.9 for the sandy subgrade, with a mean value of 3.9.

Laboratory Testing

Index Tests. The laboratory work included moisture content determinations, a Atterberg limits test, and mechanical sieve analyses to classify the soils and estimate their overall engineering properties. The results of the index tests are summarized on Table 2C (Appendix C).

Sieve gradation curves were completed on bulk samples of the sand subgrade taken form BH-4 and BH-5 (Samples S-4-1 and S-5-1). The test results (Figures 1C and 2C) indicate the samples are predominantly comprised of fine sand-sized particles with fines (silt and/or clay) contents of 9.0% and 9.2% and a resulting FAA/USCS classification of SP-SM. Fines content determinations were completed on seven additional sand subgrade samples from across the project site. Those test results indicate fines contents ranging from 1.4% to 15.0% and a resulting FAA/USCS classification of SP, SP-SM, or SM.

Toledo, Oregon 4 Century West Engineering

The Atterberg limits test was completed on a sample of the clayey silt that underlies the sand in BH-4 (Sample S-4-3). The test results indicate a liquid limit (LL) of 82 and a plasticity index (PI) of 23). These limits correspond to a FAA/USCS classification of MH.

Moisture-Density and CBR Tests. Standard Proctor moisture-density curves (ASTM D698) were developed for bulk samples S-4-1 and S-5-1. The test results, summarized in Figures 3C and 5C, indicate a maximum dry density of 97.7 pcf at an optimum moisture content of 13.2% for S-4-1 and a maximum dry density of

99.4 pcf at an optimum moisture content of 15.7% for S-5-1.

California Bearing Ratio (CBR) (ASTM D1883) tests were completed on the bulk samples identified above. The results of the moisture-density tests were used to prepare samples at densities ranging from ±93.1 to 102.5% relative compaction.

The CBR results are summarized in Figures 4C and 6C. At 95% relative compaction, the test results indicate a CBR value of 8.7 for S-4-1 and a CBR value of 12.9 for S-5-1.

DISCUSSION OF GEOTECHNICAL CONSIDERATIONS AND DESIGN RECOMMENDATIONS

The following provides a discussion of pertinent design parameters and construction considerations for new pavements.

Discussion of Subgrade Conditions

The pavement subgrade underlying the site consists of sand with varying silt content (FAA/USCS classifications of SP, SP-SM, and SM). Clayey silt (MH) underlies the sand at depths of ±2.5 to 4.5 feet. We understand the finished grade of the reconstructed apron and taxiways will lie ±6 inches above or below current grades.

Therefore, based on the limited site grading and the thickness of the sand, we recommend designing the new pavements assuming subgrade parameters consistent with sand.

Appendix A of the FAA Pavement Advisory Circular (AC 150/5320-6G) indicates sandy soils within the range of classifications identified within the project area can vary from fair to good as a foundation material. Appendix A also indicates the potential for frost action can range from none to high and drainage can range from fair to excellent. Frost susceptibility and drainage are discussed in subsequent sections of this report.

Parameters for Apron and Taxiway Pavement Design and Subgrade Preparation

This section provides recommended subgrade design parameters and subgrade preparation for full-depth reconstruction or new construction. We understand where full-depth reconstruction is planned for the taxiways, the existing ACP may be pulverized and blended with the underlying sand. Given the limited ACP thickness, we recommend modeling this treated layer as subgrade with the design parameters recommended below.

Toledo, Oregon 5 Century West Engineering

Subgrade Design Parameters. The laboratory testing indicates CBR values of 8.7 and

12.9 for sand subgrade samples compacted to 95% relative compaction (based on ASTM D698). We recommend assuming a nominal subgrade CBR value of 8 for designing new pavements to account for potential variation in the subgrade conditions across the site.

Subgrade Preparation. Excavations should be completed in accordance with Section 00330.41. Organic rich soils, where encountered, should be overexcavated and replaced with more suitable material.

The subgrade in the pavement areas should be moisture-conditioned and compacted in accordance with Section 00330.43. Prior to placing the Base Aggregate, the finished subgrade should be proof-rolled with a loaded dump truck or other approved heavy construction vehicle to identify any soft areas. Any soft or pumping subgrade should be reworked or overexcavated and replaced with additional Base Aggregate.

The moisture in the finished subgrade should be maintained and the subgrade should be backfilled with Base Aggregate as soon as practical to limit moisture fluctuations (i.e., wetting or drying).

Gravel Access Road

We understand the existing gravel access road will be paved with ACP. We anticipate the road will be constructed at or slightly above existing grades and the existing base rock will remain in place with additional Base Aggregate added to grade the terrain and construct the pavement section. Prior to placing new Base Aggregate, organics, or deleterious materials on the surface of the existing base rock should be removed and the base rock surface should be compacted.

We anticipate the subgrade will consists of a blend of existing base rock and sand.

We anticipate field density tests on the subgrade will not be practical due to the variable gradation. Therefore, we recommend proof-rolling the finished subgrade with a loaded dump truck or other approved heavy construction vehicle to evaluate the compaction of the subgrade. Any soft or pumping subgrade identified during the proof-roll, should be reworked or overexcavated and replaced with additional Base Aggregate.

We recommend designing the access road pavement assuming a subgrade CBR value of 8, consistent with the design of the apron and taxiway pavements. We anticipate the traffic loads will be relatively light and the design calculations using a CBR of 8 will likely indicate a very thin ACP section could be used. Therefore, when selecting a minimum pavement section, we recommend considering constructability and durability and specifying no less than 2 inches of ACP.

Toledo, Oregon 6 Century West Engineering

Swelling Soils

Swelling soils are clay soils that exhibit significant volume change with changes in moisture. AC 150/5320-6G identifies these soils as typically having liquid limits (LL) greater than 40 and plasticity indices (PI) greater than 25. These soils were not encountered in the borings at shallow depths. Therefore, treatment for swelling soils is not required for this project.

Frost Considerations

The subgrade includes USCS soil classifications of SP, SP-SM, and SM. According to Table 2-2 of the AC 150/5320-6G the frost group classification is FG-2 for these soil types based on percentage finer than 0.2 mm by weight as determined by laboratory testing. FG-2 subgrade is considered slightly frost-susceptible.

The local building code in Lincoln County indicates a frost penetration depth of 12 inches (referenced in Table R301.2(1) of the 2021 Oregon Residential Specialty Code). The design frost penetration depth will be greater than the new pavement sections. However, the subgrade at this site is generally considered to have low frost susceptibility due to the low fines content of the sand (typically less than 10 percent) and the location of the site near sea level. Therefore, frost susceptibly of the subgrade is not a design concern for this project and mitigation is not required.

Site Drainage

The subgrade consists of sand with variable silt content (USCS classifications SP, SP-SM, and SM). Appendix A of the FAA Pavement Advisory indicates the drainage characteristics for these soils may range from fair to poor to excellent depending on silt content. The 2013 FAA Surface Drainage Design Advisory Circular (AC 150/5320-5D), Figure G-3, indicates a wide variation in coefficient of permeability (k) values for these soil types. No field testing was completed to determine the permeability of the subgrade. However, based on our experience with similar soils, we believe it is reasonable to assume k values in the range of 10-1 to 10-4 cm/sec for evaluating drainage alternatives within the project area. Any drainage improvements should also take into consideration the shallow groundwater, which is expected to range from ±2.5 to 5 feet below the ground surface throughout the year.

Construction Timing

We recommend completing the earthwork during the dry summer months (typically July through the end of September), when it is more practical to adjust the moisture content of the soil to near optimum and compact the subgrade.

Subgrade compaction may be difficult to achieve during wet weather. Therefore, if construction during wet weather is required, a thickened base rock section may be necessary in lieu of subgrade compaction. We typically recommend a minimum of 18 to 24 inches of granular fill over a Subgrade Geotextile to reduce the risk of subgrade

Toledo, Oregon 7 Century West Engineering pumping. A reduced subgrade design strength would also be necessary for design with uncompacted subgrade.

Material Specifications and Compaction

The Base Aggregate should conform to the material requirements of Section 02630 and the grading requirements of Table 02630-1 (¾ or 1-inch – 0). Subbase Aggregate, if required, should conform to the material requirements of Section 00641.41(b)

If a Subgrade Geotextile (Separation) is required, it should be a woven geotextile conforming to the property requirements of Table 02320-4. The geotextile should be laid flat over the subgrade and pulled tight to remove wrinkles. A minimum of ±2 feet of overlap should be provided between adjacent rolls. The geotextile should overlap in the direction the fill will be placed to reduce the risk of developing slack and separating the overlapped joints. Seams that have separated will required removal of the Base Aggregate to establish the required overlap.

All fill should be placed in level lifts and compacted to a minimum of 95% relative compaction based on the maximum dry density of ASTM D698. The moisture content of the fill should be adjusted to within ±2% of its optimum value prior to compaction. Granular fill (sand, rock, or gravel) will compact most efficiently with a smooth drum, vibratory roller.

Field density tests should be run frequently to confirm adequate compaction of the Base Aggregate, Subbase Aggregate, and subgrade. Field density testing on base course sections less than 6 inches thick will not be practical. Adequate compaction of thin base course sections (e.g., Base Aggregate) and fill materials which are too coarse or too variable for density testing (e.g., Subbase Aggregate), should be evaluated by observation of the compaction method and proof-rolling with a loaded dump truck or other approved heavy construction vehicle.

DESIGN REVIEW/CONSTRUCTION OBSERVATION/TESTING

We should be provided the opportunity to review all drawings and specifications that pertain to site preparation and fill placement. Site preparation for new pavements will require field confirmation of the subgrade conditions. Mitigation of pumping subgrade and fill will also require engineering review and judgment. That judgment should be provided by one of our representatives. We recommend we be retained to provide the necessary construction observations.

VARIATION OF SUBSURFACE CONDITIONS, USE OF THIS REPORT, AND WARRANTY

The analysis, conclusions, and recommendations contained herein assume the subsurface profiles encountered in the borings are representative of the site conditions. The above recommendations assume we will have the opportunity to review final drawings and be present during construction to confirm the assumed subgrade conditions. No changes in the enclosed recommendations should be made

Toledo, Oregon 8 Century West Engineering without our approval. We will assume no responsibility or liability for any engineering judgment, inspection, or testing performed by others.

This report was prepared for the exclusive use of Century West Engineering and their design consultants for the Toledo State Airport –Taxiway and Apron Rehabilitation project in Toledo, Oregon. Information contained herein should not be used for other sites or for unanticipated construction without our written consent. This report is intended for planning and design purposes. Contractors using this information to estimate construction quantities or costs do so at their own risk. Our services do not include any survey or assessment of potential surface contamination or contamination of the soil or ground water by hazardous or toxic materials. We assume those services, if needed, have been completed by others.

Our work was done in accordance with generally accepted soil and foundation engineering practices. No other warranty, expressed or implied, is made.

Toledo, Oregon 9 Century West Engineering

REFERENCES

ASTM, 2014, Standard Test Methods for CBR (California Bearing Ratio) of Laboratory-Compacted Soil: American Society for Testing and Materials (ASTM), Standard D1883, vol. 04.08.

ASTM, 2012, Standard Tests Methods for Laboratory Compaction Characteristics of Soil Using Standard Effort (12,400ft-lbf/ft3 (600kN-m/m3)): American Society for Testing and Materials (ASTM), Standard D698, vol. 04.08.

FAA, 2021, Airport Pavement Design and Evaluation Advisory Circular:

AC No. 150/5320-6G, Federal Aviation Administration.

FAA, 2013, Subsurface Drainage Design Advisory Circular: AC No. 150/5320-5D, Federal Aviation Administration.

ODOT, 2019, ODOT Pavement Design Guide, Oregon Department of Transportation (ODOT), Pavement Services Unit.

ODOT, 2021, Oregon Standard Specifications for Construction, Oregon Department of Transportation (ODOT).

ORSC, 2021, Oregon Residential Specialty Code (ORSC): Based on 2018 International Residential Code (IRC), International Code Council, Inc., ISBN-978-1-955052-96-2.

Appendix A Figures

2,0001,000500

SCALE IN FEET

SITE

Foundation Engineering, Inc.

Professional Geotechnical Services

Dec. 14, 2021

PROJECT NO.

FIGURE NO.

DRAWN BY:DATE:

VICINITY MAP

TOLEDO STATE AIRPORT

TAXIWAY AND APRON REHABILITATION

TOLEDO, OREGON

MDM2211103

1A

Note: Base map obtained from USGS.

BH-9

BH-1

BH-2

BH-7

BH-8

BH-4

BH-6

BH-5

BH-3

Foundation Engineering, Inc.

Professional Geotechnical Services

Dec. 14, 2021

PROJECT NO.

FIGURE NO.

DRAWN BY:DATE:

SITE LAYOUT AND BORING LOCATIONS

TOLEDO STATE AIRPORT

TAXIWAY AND APRON REHABILITATION

TOLEDO, OREGON

MDM2211103

2A

NOTES:

1. BORING LOCATIONS ARE APPROXIMATE ONLY.

2. SEE REPORT FOR A DISCUSSION OF SUBSURFACE CONDITIONS.

3. BASE MAP PROVIDED BY CENTURY WEST ENGINEERING.

- BORING (BH-1)

NO SCALE

Appendix B Boring Logs and Core Photos

Foundation Engineering, Inc.

Professional Geotechnical Services

NVilleneuve Image

EXPLORATION LOGS

SYMBOL KEY

DISTINCTION BETWEEN FIELD LOGS AND FINAL LOGS

A field log is prepared for each boring or test pit by our field representative. The log contains information concerning sampling depths and the presence of various materials such as gravel, cobbles, and fill, and observations of ground water. It also contains our interpretation of the soil conditions between samples.

The final logs presented in this report represent our interpretation of the contents of the field logs and the results of the sample examinations and laboratory test results. Our recommendations are based on the contents of the final logs and the information contained therein and not on the field logs.

VARIATION IN SOILS BETWEEN TEST PITS AND BORINGS

The final log and related information depict subsurface conditions only at the specific location and on the date indicated. Those using the information contained herein should be aware that soil conditions at other locations or on other dates may differ. Actual foundation or subgrade conditions should be confirmed by us during construction.

TRANSITION BETWEEN SOIL OR ROCK TYPES

The lines designating the interface between soil, fill or rock on the final logs and on subsurface profiles presented in the report are determined by interpolation and are therefore approximate. The transition between the materials may be abrupt or gradual. Only at boring or test pit locations should profiles be considered as reasonably accurate and then only to the degree implied by the notes thereon.

SH - 3 - 4

Bottom of Sample Attempt

Unrecovered Portion

Exploration Number

Recovered Portion

Top of Sample Attempt

Sample Type

Sample Number

SAMPLE OR TEST SYMBOLS

C - Pavement Core Sample

CS - Rock Core Sample

OS - Oversize Sample (3-inch O.D. split-spoon)

S - Grab Sample

SH - Thin-walled Shelby Tube Sample

SS - Standard Penetration Test Sample

(2-inch O.D. split-spoon)

FIELD SHEAR STRENGTH TEST

Shear strength measurements on test pit side walls, blocks of soil or Shelby tube samples are typically made with Torvane or Field Vane shear devices.

TYPICAL SOIL/ROCK SYMBOLS

WATER TABLE

Water Table Location

Date of Measurement(1/31/16)

Concrete

Organics

Clay

Gravel

Silt

Sand Sandstone

Basalt

Siltstone

Standard Penetration Test Resistance equals the number of blows a 140 lb. weight falling 30 in. is required to drive a standard split-spoon sampler 1 ft. Practical refusal is equal to 50 or more blows per 6 in. of sampler penetration.

Water Content (%)

UNIFIED SOIL CLASSIFICATION SYMBOLS

G - Gravel

S - Sand

M - Silt

C - Clay

Pt - Peat

W - Well Graded

P - Poorly Graded

L - Low Plasticity

H - High Plasticity

O - Organic

COMMON TERMS

SOIL DESCRIPTIONS

Explanation of Common Terms Used in Soil Descriptions

Field Identification

Cohesive Soils Granular Soils

SPT*

S u

** (tsf)

Term SPT* Term

Easily penetrated several inches by fist.

0 - 2 < 0.125

Very Soft

0 - 4

Very Loose

Easily penetrated several inches by thumb.

2 - 4

0.125 - 0.25 Soft 4 - 10 Loose

Can be penetrated several inches by thumb with moderate effort.

4 - 8 0.25 - 0.50 Medium Stiff 10 - 30 Medium Dense

Readily indented by thumb but penetrated only with great effort.

8 - 15 0.50 - 1.0 Stiff 30 - 50 Dense

Readily indented by thumbnail.

15 - 30 1.0 - 2.0

Very Stiff

> 50

Very Dense

Indented with difficulty by thumbnail.

> 30 > 2.0 Hard

Term

Soil Moisture Field Description

Dry Absence of moisture. Dusty. Dry to the touch.

Damp Soil has moisture. Cohesive soils are below plastic limit and usually moldable.

Moist

Grains appear darkened, but no visible water. Silt/clay will clump. Sand will bulk. Soils are often at or near plastic limit.

Wet

Visible water on larger grain surfaces. Sand and cohesionless silt exhibit dilatancy. Cohesive soil can be readily remolded. Soil leaves wetness on the hand when squeezed. Soil is wetter than the optimum moisture content and above the plastic limit.

Term PI

Plasticity Field Test

Non-plastic

0 - 3

Cannot be rolled into a thread at any moisture.

Low Plasticity

3 - 15

Can be rolled into a thread with some difficulty.

Medium Plasticity

15 - 30

Easily rolled into thread.

High Plasticity

> 30

Easily rolled and re-rolled into thread.

Term Soil Structure Criteria

Stratified

Alternating layers at least ¼ inch thick.

Laminated

Alternating layers less than ¼ inch thick.

Fissured

Contains shears and partings along planes of weakness.

Slickensided

Partings appear glossy or striated.

Blocky

Breaks into small lumps that resist further breakdown.

Lensed

Contains pockets of different soils.

Term Soil Cementation Criteria

Weak

Breaks under light finger pressure.

Moderate

Breaks under hard finger pressure.

Strong Will not break with finger pressure.

* SPT N-value in blows per foot (bpf)

** Undrained shear strength

Rapid seepage at ±1.2 feet.

S-1-1

S-1-2

S-1-3

ASPHALTIC CONCRETE (±2 inches).

SAND, trace silt (SP); brown, wet, medium dense, fine sand, (fill).

SAND, some silt (SP-SM); grey, non-plastic silt, wet, medium dense, fine sand, (fill).

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

0.2

1.3

4.0

5.0

Comments

BH-1

BORING LOG: BH-1

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L o g Soil / Rock Description

Rapid seepage at ±1.4 feet.

S-2-1

S-2-2

S-2-3

ASPHALTIC CONCRETE (±2¼ inches).

SAND, some silt (SP-SM); brown, non-plastic silt, wet, medium dense, fine sand, (fill).

Grey below ±2 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

0.2

3.5

5.0

Comments

BH-2

BORING LOG: BH-2

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L o g Soil / Rock Description

Rapid seepage at ±10 inches.

S-3-1

S-3-2

S-3-3

SLURRY SEAL (±1 inch).

SAND, some silt (SP-SM); brown, non-plastic silt, wet, medium dense, fine sand, (fill).

Grey below ±2.5 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

0.1

4.0

5.0

Comments

BH-3

BORING LOG: BH-3

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L o g Soil / Rock Description

Rapid seepage at ±12 inches.

S-4-1

S-4-2

S-4-3

SAND, some silt (SP-SM); brown, non-plastic silt, moist, medium dense, fine sand, (fill).

Wet below ±12 inches.

Grey below ±2 feet.

Clayey SILT, scattered organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

2.5

5.0

Comments

BH-4

BORING LOG: BH-4

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L

Rapid seepage at ±1.2 feet.

S-5-1

S-5-2

S-5-3

SAND, some silt (SP-SM); brown, non-plastic silt, moist, medium dense, fine sand, (fill).

Wet below ±1.2 feet.

Grey below ±2.5 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

3.5

5.0

Comments

BH-5

BORING LOG: BH-5

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L o g Soil / Rock Description

Rapid seepage at ±1.5 feet.

S-6-1

S-6-2

S-6-3

Silty SAND (SM); brown, non-plastic silt, moist, medium dense, fine sand, (fill).

Wet below ±1.5 feet.

Grey with some silt below ±2.5 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

4.5

5.0

Comments

BH-6

BORING LOG: BH-6

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L

Rapid seepage at ±4 inches.

S-7-1

S-7-2

S-7-3

Organic SILT, trace sand and gravel (OL); grey-brown, low plasticity, wet, soft, fine sand, fine subangular to subrounded gravel, organics consist of fine roots, (fill).

SAND, some silt (SP-SM); brown, non-plastic silt, wet, medium dense, fine sand, (fill).

Grey below ±2 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

0.5

3.5

5.0

Comments

BH-7

BORING LOG: BH-7

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L o g Soil / Rock Description

Rapid seepage at ±12 inches.

S-8-1

S-8-2

S-8-3

Organic SILT, some sand (OL); grey-brown, low plasticity, wet, soft, fine sand, organics consist of fine roots, (fill).

SAND, trace silt (SP); brown, wet, medium dense, fine sand, (fill).

SAND, some silt (SP-SM); brown, non-plastic silt, wet, medium dense, fine sand, (fill).

Grey below ±3 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

0.5

2.0

4.0

5.0

Comments

BH-8

BORING LOG: BH-8

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L

Rapid seepage at ±12 inches. S-9-1

S-9-2

S-9-3

CRUSHED ROCK (GP); grey, wet, medium dense, ±1-inch minus angular rock, (fill).

Silty SAND (SM); brown, non-plastic silt, wet, medium dense, fine sand, (fill).

Grey with some silt below ±2.5 feet.

Clayey SILT, some organics (MH); grey-brown, medium plasticity, wet, soft, organics consist of grass and wood fibers, (alluvium).

BOTTOM OF EXPLORATION

0.5

4.0

5.0

Comments

BH-9

BORING LOG: BH-9

Toledo State Airport

Taxiway and Apron Rehabilitation

Toledo, Oregon

Project No.: 2211103

Surface Elevation: N/A

Date of Exploration: November 30, 2021

D ep th ft

S am p le

N u m b er

L o ca ti o n

S u ts f)

E le v.

D ep th

L

Project No.: 2211103

Photo 1. Pavement Core at BH-1

Photo 2. Pavement Core at BH-2

Appendix C Field and Laboratory Testing

Foundation Engineering, Inc.

Professional Geotechnical Services

NVilleneuve Image

Table 1C. Summary of DCP Test Results

Borehole Initial Test Depth

(inches)

Soil Description 1Average

DCP

(mm/blow)

2Average

MR

(psi)

3Corrected Mr

(psi)

4Correlated

CBR

Value

BH-1

2.0 SAND, trace silt (SP) 9.0 20,853 7,299 4.9

48.0 Clayey SILT, some

organics (MH) 36.7 12,032 4,211 2.8

BH-2 2.5 SAND, some silt

(SP-SM) 14.0 17,515 6,130 4.1

BH-3

4.0 SAND, some silt

(SP-SM) 15.9 16,687 5,840 3.9

48.0 Clayey SILT, some

organics (MH) 55.9 10,207 3,572 2.4

BH-4

18.0 SAND, some silt

(SP-SM) 28.6 13,256 4,640 3.1

32.0 Clayey SILT, scattered

organics (MH) 67.5 9,484 3,319 2.2

BH-5

21.5 SAND, some silt

(SP-SM) 24.7 14,035 4,912 3.3

48.0 Clayey SILT, some

organics (MH) 98.3 8,189 2,866 1.9

BH-6 11.0 Silty SAND (SM) 14.7 17,200 6,020 4.0

BH-7 7.0 SAND, some silt

(SP-SM) 19.6 15,348 5,372 3.6

BH-9 12.0 Silty SAND (SM) 10.0 19,971 6,990 4.7

Notes: 1. DCP (mm/blow) based on the average readings from the initial test depth.

2. MR value based on average DCP value at the test depth and the ODOT (2019) recommended correlation:

MR = 49,023 (DCP)-0.39. Values may vary slightly due to rounding.

3. Corrected MR value is based on the ODOT (2019) recommended correction factor if 0.35 for subgrade.

4. Correlated CBR value for subgrade is based on the FAA recommended correlation of MR = 1,500*CBR.

Table 2C. Moisture Content, Percent Fines & Atterberg Limits

Sample Number

Sample Depth (ft)

Moisture Content (percent)

Percent Fines

Atterberg Limits FAA/USCS Classification LL PL PI

S-1-1 0.3 – 1.0 21.4 1.4 SP

S-2-1 0.3 – 1.5 23.4 9.9 SP-SM

S-2-3 3.5 – 4.5 129.9

S-3-1 0.3 – 1.3 22.5 11.3 SP-SM

S-4-1 0 – 1.5 9.0 SP-SM

S-4-3 3.0 – 4.0 74.6 82 59 23 MH

S-5-1 0 – 1.8 9.2 SP-SM

S-5-3 3.5 – 4.5 97.2

S-6-1 0 – 1.0 17.0 14.5 SM

S-7-1 0.5 – 1.5 27.8 9.4 SP-SM

S-8-1 0.5 – 1.5 29.9 2.4 SP

S-9-1 1.0 – 2.0 27.2 15.0 SM

FEI Testing & Inspection, Inc.

Corvallis, OR

12-03-2021

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= SP-SM AASHTO=

1/4" #4 #10 #20 #40 #60

#100 #200

100.0 99.8 99.3 98.7 94.3 51.4 15.5

9.0

0.3937 0.3661 0.2745

0.2461 0.1926 0.1419

0.0833 3.29 1.62

Foundation Engineering, Inc.

Toledo State Airport - Taxiway and Apron Rehabilitation

2216001-622

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Source of Sample: 8391 Depth: 0.0-1.5' Sample Number: S-4-1 Date:

Client:

Project:

Project No: Figure 1C

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 0.0 0.2 0.5 5.0 85.3 9.0 in in in

½ in in

¾ in

½ in

/8 in

Sieve Analysis ASTM C 117/C 136

SAND, some silt

FEI Testing & Inspection, Inc.

Corvallis, OR

12-03-2021

(no specification provided)

PL= LL= PI=

D90= D85= D60= D50= D30= D15= D10= Cu= Cc=

USCS= SP-SM AASHTO=

1/4" #4 #10 #20 #40 #60

#100 #200

100.0 99.9 99.7 99.4 94.3 48.3 14.9

9.2

0.3965 0.3709 0.2828

0.2547 0.1991 0.1504

0.0828 3.42 1.69

Foundation Engineering, Inc.

Toledo State Airport - Taxiway and Apron Rehabilitation

2216001-622

Material Description

Atterberg Limits

Coefficients

Classification

Remarks

Source of Sample: 8391 Depth: 0.0-1.8' Sample Number: S-5-1 Date:

Client:

Project:

Project No: Figure 2C

SIEVE PERCENT SPEC.* PASS?

SIZE FINER PERCENT (X=NO)

P E

R C

E N

T F

IN

E

R

GRAIN SIZE - mm.

0.0010.010.1110100

% +3" Coarse

% Gravel

Fine Coarse Medium

% Sand

Fine Silt

% Fines

Clay

0.0 0.0 0.1 0.2 5.4 85.1 9.2 in in in

½ in in

¾ in

½ in

/8 in

Sieve Analysis ASTM C 117/C 136

MOISTURE - DENSITY RELATIONSHIP CURVE

D ry d e n si ty p cf

Water content, %

7.5 9 10.5 12 13.5 15 16.5

Test specification: ASTM D 698-12 Method A Standard

0.0-1.5' 0.2 9.0

2216001-622 Foundation Engineering, Inc.

Date: 12-03-2021

Elev/ Classification Nat.

Sp.G. LL PI

Depth USCS AASHTO Moist. #4 No.200

TEST RESULTS MATERIAL DESCRIPTION

Project No. Client: Remarks:

Project:

Source of Sample: 8391 Sample Number: S-4-1

FEI Testing & Inspection, Inc.

Corvallis, OR Figure 3C

Maximum dry density = 97.7 pcf

Optimum moisture = 13.2 %

Toledo State Airport - Taxiway and Apron Rehabilitation

SP-SM

BEARING RATIO TEST REPORT

ASTM D1883-05

BEARING RATIO TEST REPORT

FEI Testing & Inspection, Inc.

Corvallis, OR

Project No: 2216001-622

Project: Toledo State Airport

Source of Sample: 8391 Depth: 0.0-1.5'

Sample Number: S-4-1

Date: 12-03-2021

Test Description/Remarks:

Figure 4C

97.7 13.2

Material Description

USCS

Max.

Dens.

(pcf)

Optimum Moisture

LL PI

Molded

Density (pcf)

Percent of Max. Dens.

Moisture

Soaked

Density (pcf)

Percent of Max. Dens.

Moisture

CBR (%)

0.10 in. 0.20 in.

Linearity Correction

(in.)

Surcharge (lbs.)

Max.

Swell

1 91.0 93.1 13.4 90.9 93 20.3 4.9 6.7 0.000 32 0.1

2 94.4 96.6 13.4 94.3 96.6 20.0 7.7 11.1 0.000 32 0.1

3 100.9 103.3 13.8 100.9 103.3 17.3 19.1 28.8 0.000 32 0

P e n e tr a ti o n

R e s is ta n c e p s i)

Penetration Depth (in.)

0 0.1 0.2 0.3 0.4 0.5

S w e ll

0.1

0.2

0.3

0.4

0.5

Elapsed Time (hrs) 0 24 48 72 96

C B

R

Molded Density (pcf) 90 93 96 99 102 105

10 blows

20 blows

56 blows

CBR at 95% Max. Density = 8.7% for 0.20 in. Penetration

SAND, some silt SP-SM

MOISTURE - DENSITY RELATIONSHIP CURVE

D ry d e n si ty p cf

94.5

97.5

100.5

Water content, %

7.5 10 12.5 15 17.5 20 22.5

Test specification: ASTM D 698-12 Method A Standard

0.0-1.8' 0.1 9.2

2216001-622 Foundation Engineering, Inc.

Date: 12-03-2021

Elev/ Classification Nat.

Sp.G. LL PI

Depth USCS AASHTO Moist. #4 No.200

TEST RESULTS MATERIAL DESCRIPTION

Project No. Client: Remarks:

Project:

Source of Sample: 8391 Sample Number: S-5-1

FEI Testing & Inspection, Inc.

Corvallis, OR Figure 5C

Maximum dry density = 99.4 pcf

Optimum moisture = 15.7 %

Toledo State Airport - Taxiway and Apron Rehabilitation

SP-SM

BEARING RATIO TEST REPORT

ASTM D1883-05

BEARING RATIO TEST REPORT

FEI Testing & Inspection, Inc.

Corvallis, OR

Project No: 2216001-622

Project: Toledo State Airport

Source of Sample: 8391 Depth: 0.0-1.8'

Sample Number: S-5-1

Date: 12-03-2021

Test Description/Remarks:

Figure 6C

99.4 15.7

Material Description

USCS

Max.

Dens.

(pcf)

Optimum Moisture

LL PI

Molded

Density (pcf)

Percent of Max. Dens.

Moisture

Soaked

Density (pcf)

Percent of Max. Dens.

Moisture

CBR (%)

0.10 in. 0.20 in.

Linearity Correction

(in.)

Surcharge (lbs.)

Max.

Swell

1 92.8 93.4 15.6 92.7 93.3 19.9 6.7 9.2 0.000 32 0.1

2 97.6 98.2 15.5 97.5 98.1 18.3 13.9 19.4 0.000 32 0.1

3 102.5 103.1 15.6 102.5 103.1 16.1 13.5 25.7 0.000 32 0

P e n e tr a ti o n

R e s is ta n c e p s i)

Penetration Depth (in.)

0 0.1 0.2 0.3 0.4 0.5

S w e ll

0.1

0.2

0.3

0.4

0.5

Elapsed Time (hrs) 0 24 48 72 96

C B

R

Molded Density (pcf) 92 95 98 101 104 107

10 blows

20 blows

56 blows

CBR at 95% Max. Density = 12.9% for 0.20 in. Penetration

SAND, some silt SP-SM