Attachment C - Memaloose Pavement and Geotechnical Report.pdf

9450 SW COMMERCE CIRCLE, SUITE 300 | WILSONVILLE, OR 97070 | WWW.NV5.COM | OFFICE 503.968.8787

October 5, 2021

Kittelson & Associates Inc.

851 SW 6th Avenue, Suite 600 Portland, OR 97204

Attention: Jamestaun B. Kraupp

Report of Pavement and Geotechnical Engineering Services Oregon Travel Information Council Project

Maples Rest Area – Milepost 34.5, Oregon 22 Memaloose Rest Areas – Milepost 72.6, Interstate 84

Marion and Wasco Counties, Oregon Project: OregonTIC-3-01

INTRODUCTION

NV5 is pleased to submit this report of pavement and geotechnical engineering services for the Maples rest area at milepost 34.5 on Oregon 22 (OR 22) and Memaloose rest areas at milepost 72.6 on Interstate 84 (I-84) in Marion and Wasco Counties, Oregon, respectively. Our pavement design and construction recommendations are based on the results of on-site visual evaluations, subsurface explorations, dynamic cone penetration (DCP) testing, traffic loading derived from recent vehicle classification counts, and discussions with Oregon Traffic Information Council (TIC) personnel.

Figures 1 and 2 shows the approximate locations of the rest areas and Figures 3 through 5 provide site plans identifying the approximate locations of our pavement explorations at each rest area.

Based on our understanding, TIC will be designing and constructing improvements to the Maples (single) rest area and Memaloose (dual eastbound and westbound) rest areas. In addition, we understand that geotechnical elements related to improvements are limited to pavement rehabilitation for paving TIC-owned pavement at each rest area and foundation recommendations for new or modified single-story masonry structures.

SCOPE OF SERVICES

The project includes evaluation and analysis of data derived from pavement testing and explorations to provide pavement rehabilitation or reconstruction recommendations. We completed the following specific scope of services:

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Identified exploration locations and provided a site plan to the project team for review.

Completed three borings for building foundation design to depths of up to 7.3 feet below ground surface (BGS) using solid-stem auger methods. One boring each was completed at Maples, one at eastbound Memaloose, and one at westbound Memaloose.

Completed 12 pavement borings to depths of up to 4.5 feet BGS using a diamond core bit followed with solid-stem auger.

Four borings were completed at the Maples rest area.

Four borings were completed at the westbound Memaloose rest area.

Four borings were completed at the eastbound Memaloose rest area.

DCP testing was conducted in each boring.

Borings in pavement were repaired with polymer-modified asphalt patch.

Maintained a detailed log of each exploration, visually classified the soil encountered, collected soil samples as appropriate for the soil conditions encountered, and observed for any groundwater conditions in the explorations.

Conducted the following laboratory tests on soil samples collected from the explorations:

Eleven moisture content test determinations in general accordance with ASTM D2216

Reviewed and discussed traffic information and estimates with the project team.

Estimated required and existing pavement capacity based on traffic information, subsurface explorations, and DCP results.

Provided recommendations for pavement repair and reconstruction as required.

Provided rehabilitation recommendations for 15- to 20-year rehabilitation lives for the existing pavement.

Provided geotechnical foundation recommendations for single-story masonry buildings.

Provided recommendations for materials and construction.

Completed this report.

SITE CONDITIONS

Maples is composed of a rest area servicing eastbound OR 22. The rest area consists of semi-truck/trailer and car parking areas. Memaloose is composed of two rest areas, one servicing eastbound I-84 and the other servicing westbound I-84. In general, the rest areas have similar configurations with separate truck and car parking areas. Site grades are generally flat. The pavement is asphalt concrete (AC) surfacing for all the rest areas.

GEOLOGICAL CONDITIONS

Maples Rest Area The Maples rest area site is located on the north bank of the Santiam River, approximately

1.75 miles east of Gates, Oregon. Geologically, the site is situated in the Western Cascade geologic province of Oregon, an older and more significantly eroded portion of the Cascade Range (Orr and Orr, 2000).1

1 Orr, Elizabeth L., and Orr, William N., 2000, Geology of Oregon, 5th ed., Kendall/Hunt Publishing Company, Dubuque, Iowa, 254 p.

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Bedrock in the area consists of undifferentiated, tuffaceous sedimentary rocks; basalt flows; and tuffs dating from the Miocene and Oligocene (Walker and Duncan, 1989).2 These rocks were erupted and deposited between 32 million and 17 million years ago. Quaternary alluvium (unconsolidated clay, silt, sand, and gravel) deposited by the Santiam River covers the bedrock locally along the valley floor. Detailed geologic mapping of the area has not been completed, and our field reconnaissance indicates that the topographic highs in the area are underlain by a large, relatively homogeneous basaltic andesite flow.

Memaloose Rest Areas The Memaloose rest areas site is situated on the southwestern margin of the Columbia Plateau physiographic province (Orr and Orr, 2000).3 The main geologic unit in the province consists of extensive volcanic flows of the Columbia River Basalt Group (CRBG), which is a series of flood basalt flows that originated from southeastern Washington and northeastern Oregon. The CRBG flows filled the lowlands and drainages formed by tectonic folding and the ancient Columbia River (Tolan et al., 2002).4 The CRBG was folded and faulted by tectonic forces associated with the region-wide Yakima Fold Belt located to the north in Washington. Several unnamed faults are in the site vicinity; however, they were likely formed under a different tectonic regime than what is present today and are not considered by the U.S. Geological Survey5 to be active.

Based on geologic mapping, the surficial geologic unit underlying the site consists of basalt flows of the Miocene Age (approximately 15 million years before present).6 The basalt lava flows were likely covered by river alluvium and volcanic deposits from the nearby Cascade Range. However, the deposits were likely removed by downcutting by the Columbia River and scouring of the valley during the outpouring of massive flood waters of the Pleistocene Age (approximately 15,000 to 12,000 years before present) Missoula floods. The Missoula floods were a series of large-scale glacial outburst flood events that travelled down the Columbia River valley and scoured the site vicinity down to the underlying basalt bedrock.

EXISTING SURFACE CONDITIONS

Maples Rest Area In general, the pavement is in fair condition, except for two isolated moderate to severe fatigue areas, one near the entrance and the other near the semi-truck/trailer parking at the southern portion of the rest area. The moderate to severe fatigue area makes up approximately 6 percent of the total pavement area. Distress areas are identified as orange polygons on Figure 3.

2 Walker, W.W., and Duncan, R.A., 1989, Geologic Map of the Salem 1-Minute by 2-Minute Quadrangle, Western Oregon: U.S. Geological Survey, Miscellaneous Investigations Series Map I-1893, 1 map, scale 1:250,000

3 Orr, Elizabeth L., and Orr, William N., 2000, Geology of Oregon, 5th ed., Kendall/Hunt Publishing Company, Dubuque, Iowa, 254 p.

4 Tolan, Terry L., Beeson, Marvin H., and Lindsey, Kevin A., 2002, The Effects of Volcanism on the Evolution of the Columbia River System, Northwest Geological Society Field Guide Series, September 28-29, 2002, 74 p.

5 Korosec, Michael, A., 1987, Geologic Map of the Hood River Quadrangle, Washington and Oregon, Washington Division of Geology and Earth Resources Open File Report 87-6, 42 p., scale 1:100,000.

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Memaloose Rest Areas These two areas are similar in configuration and in distress. In general, the pavement in the drive aisles is in fair condition with intermittent low severity fatigue and thermal cracking throughout. However, within the truck parking stalls, there is considerable distress, predominantly moderate to severe fatigue cracking, where the trucks and trailers typically park and idle. The moderate to severe fatigue area makes up approximately 4 percent of the total pavement area. Distress areas are identified as orange polygons on Figures 4 and 5.

SUBSURFACE CONDITIONS

Subsurface explorations were conducted on June 28, 2021 (Maples), and June 29, 2021 (Memaloose). We explored the pavement, base, and subgrade conditions by completing 12 pavement borings (C-1 through C-4 in each rest area) on the existing pavement. In addition, we explored subsurface conditions for the proposed masonry structures by completing one off-pavement boring at each rest area (designated as B-1 for each location). All pavement borings were extended through the pavement section and into the subgrade to depths of up to 4.5 feet BGS, except for C-2 at Memaloose eastbound and C-3 at Memaloose westbound that were terminated due to refusal. The approximate exploration locations are shown on Figures 3 through 5. The exploration logs and core photographs are presented in Attachments A through C.

We performed pavement borings to the bottom of the AC layer at select locations to determine AC thickness. We drilled most of the cores on cracks to determine crack depth penetration. The existing pavement thickness at each exploration location is summarized in Table 1. A summary of distress noted in the pavement cores is shown in Table 2.

Table 1. Pavement Subsurface Summary – Thickness

Core Number

Rest Area Direction Location Layer Thickness

(inches) AC Base

C-1 Maples Eastbound Drive Aisle 2.3 5.7 C-2 Maples Eastbound Truck – Front 4.5 15.5 C-3 Maples Eastbound Truck – Back 2.5 8.5 C-4 Maples Eastbound Truck – Back 2.5 9.0

C-1 Memaloose Eastbound Drive Aisle 10.0 10.0 C-2 Memaloose Eastbound Truck 11.0 5.0 C-3 Memaloose Eastbound Truck 8.0 10.0 C-4 Memaloose Eastbound Drive Aisle 11.0 7.0

C-1 Memaloose Westbound Drive Aisle 5.3 6.7 C-2 Memaloose Westbound Truck 9.0 3.0 C-3 Memaloose Westbound Truck 12.0 12.0 C-4 Memaloose Westbound Drive Aisle 11.0 7.0

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Table 2. Pavement Subsurface Summary – Distress

Rest Area Direction Location Cracking

Zone (inches)

Stripping Zone

(inches)

Delamination Location (inches)

C-1 Maples Eastbound Drive Aisle 0 to 2.3 NP NP C-2 Maples Eastbound Truck – Front 0 to 2.5 NP NP C-3 Maples Eastbound Truck – Back 0 to 2.5 NP NP C-4 Maples Eastbound Truck – Back 0 to 2.5 NP NP

C-1 Memaloose Eastbound Drive Aisle 0 to 10.0 NP 3.3; 6.3 C-2 Memaloose Eastbound Truck 0 to 2.3 NP 4.5 C-3 Memaloose Eastbound Truck 0 to 8.0 NP 1.8 C-4 Memaloose Eastbound Drive Aisle 0 to 1.3 NP 1.3; 4.3

C-1 Memaloose Westbound Drive Aisle 0 to 2.5 NP NP C-2 Memaloose Westbound Truck 0 to 9.0 3.3 to 9.0 1.5; 3.3 C-3 Memaloose Westbound Truck 0 to 2.5 6.8 to 12.0 2.5; 6.8 C-4 Memaloose Westbound Drive Aisle 0 to 2.8 4.0 to 11.0 2.8; 4.0

NP: No distress in core; may still be distress near core location.

Maples Rest Area The pavement consists of 2.3 to 4.5 inches of AC over 5.7 to 15.5 inches of aggregate base. All the cores were completed on cracks. Cracks for C-1, C-3, and C-4 were continuous through the core. The crack at C-2 extended from the surface to 2.5 inches. We did not observe any stripping or delamination on any cores.

The near-surface soil consists of very loose to medium dense, silty sand to sand with silt. In addition, very dense gravel was encountered in B-1 at 6 feet BGS and the boring was terminated at 7.3 feet BGS due to refusal on the very dense gravel. The moisture content of the subgrade varied from 29 to 35 percent at the time of the explorations. Specific subsurface conditions, laboratory results, and layer thicknesses are identified on the exploration logs presented in Attachment A.

Memaloose Rest Areas In general, the pavement in both rest areas consists of 5.3 to 12.0 inches of AC over 3.0 to

12.0 inches of aggregate base. All cores were completed on cracks. Crack depth varies from

1.3 to 10.0 inches. For delamination, we observed variable depths from 1.3 to 6.8 inches on seven cores. Stripping was not observed for the cores in the eastbound direction; however, three out of four westbound cores exhibited stripping between 3.3 to 12.0 inches.

The subgrade generally consists of medium dense to very dense gravel (weathered basalt) with varying amounts of silt and sand at the pavement borings and medium dense to very dense sand at the masonry building borings, with the exception of medium stiff silt below the gravel at westbound C-2. Westbound borings B-1, C-1, C-3, and C-4 and eastbound borings B-1, C-1

6 OregonTIC-3-01:100521 through C-3 met refusal prior to completion. We observed basalt outcroppings in the site vicinity during our field exploration. Based on observations and geologic mapping, we anticipate that bedrock is within 20 feet of the ground surface. The moisture content of the subgrade varied from 3 to 11 percent at the time of the explorations. Specific subsurface conditions, laboratory results, and layer thicknesses are identified on the exploration logs presented in Attachments B and C.

DCP DATA

DCP TESTING

We conducted DCP testing in general accordance with ASTM D6951 to estimate the resilient modulus of the base as well as the subgrade resilient modulus at approximately one-half of the pavement boring locations. We recorded penetration depth of the cone for each blow of the hammer and terminated testing when at refusal of penetration or end of rod length. We plotted depth of penetration versus blow count and visually assessed where the slope of the data plot was relatively constant and at depths where the slope of the data plot changed significantly. We used the first slope of the data plot to estimate the base layer resilient modulus. We used the slope of the data beyond the first change in slope to estimate the resilient modulus of the subgrade. We used least squares regression to determine the slopes and the equation from the ODOT guide7 to estimate the moduli using a correction factor cf = 0.62 for estimating the base layer moduli and cf = 0.35 for estimating the subgrade resilient moduli. Table 3 lists our estimates of base layer resilient modulus and subgrade resilient modulus at each test location.

Table 3. Base Modulus and Subgrade Modulus Estimated from DCP Testing

Rest Area Direction Estimated Resilient Modulus

(psi) Aggregate Base Subgrade

C-1 Maples Eastbound 12,160 4,730 C-2 Maples Eastbound 23,870 4,340 C-3 Maples Eastbound 13,280 5,600

C-4 Maples Eastbound 13,030 3,890

C-1 Memaloose Eastbound 23,770 Refusal C-2 Memaloose Eastbound 22,740 Refusal C-3 Memaloose Eastbound 27,220 8,410 C-4 Memaloose Eastbound 18,600 Refusal

C-1 Memaloose Westbound 32,780 Refusal C-2 Memaloose Westbound 17,670 Refusal C-3 Memaloose Westbound 21,290 Refusal C-4 Memaloose Westbound 23,240 Refusal

Refusal: Exploration terminated before subgrade due to refusal psi: pounds per square inch

7 ODOT Pavement Design Guide, Pavement Services Unit, Oregon Department of Transportation, January 2019.

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PAVEMENT DESIGN

Properties of existing pavement are based on subsurface explorations and DCP testing. Traffic loading is based on the data obtained from Oregon Department of Transportation (ODOT).

Descriptions of our input parameters and the recommended pavement designs are summarized below.

DESIGN STANDARDS

The standards used for pavement design are listed below:

Guide for Design of Pavement Structures, AASHTO (1993) (AASHTO guide) ODOT guide

ESAL CALCULATIONS

For Maples, we received rest area traffic volume information from TIC for the month of June 2021. To estimate the truck distribution, we obtained traffic classification counts from the ODOT traffic counting website8 for the eastbound direction of OR 22 at milepost 33.86. Truck distribution percentages from OR 22 were applied to the TIC-supplied traffic volumes.

For Memaloose, we obtained ramp traffic volume information from the ODOT website for the rest area ramps. For truck distribution, we obtained traffic classification counts from the ODOT website for the eastbound direction of I-84 at milepost 76.65 counted in 2019. Truck distribution percentages from I-84 were applied to the ramp volumes and the ramp volumes were assumed to represent the traffic within the rest area.

We calculated 15- and 20-year equivalent single-axle loads (ESALs) assuming no annual growth will occur. The resulting 15- and 20-year ESALs for both the rest areas are summarized in Table 4.

Table 4. ESAL Calculation Summary

Rest Area 15-Year ESAL 20-Year ESAL

Maples 352,000 469,000 Memaloose 671,000 895,000

In addition, we recommend a design ESAL of 10,000 for parking only occupied by automobiles.

BASE LAYER AND SUBGRADE RESILIENT MODULI

We used the results obtained from DCP testing listed in Table 3 to determine design resilient moduli for the base layer and subgrade for each section. We calculated the average value for each set of results as recommended by the AASHTO guide. An 8,000 psi subgrade modulus was selected for Memaloose due to the variable subgrade conditions. Table 5 lists our recommendations for design resilient moduli.

8 https://www.oregon.gov/odot/Data/Pages/Traffic-Counting.aspx accessed on August 5, 2021

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Table 5. Recommended Design Resilient Moduli

Rest Area Design Resilient Modulus

(psi) Base Layer Subgrade

Maples 15,500 5,000 Memaloose 23,400 8,000

STRUCTURAL LAYER COEFFICIENTS FOR EXISTING PAVEMENT

We used our observations during the site visits to estimate the layer coefficient for the existing AC in each area in conjunction with Table 5.2 in Part III, Section 5.4.5 in the AASHTO guide. We used the base layer moduli listed in Table 5 to estimate the layer coefficients for the base layers using Figure 2.6 in Part II, Section 2.3.5 in the AASHTO guide. Table 6 lists the layer coefficients for existing AC and existing base determined in these ways.

Table 6. Estimated Structural Layer Coefficients of Existing AC and Base

Rest Area Structural Layer Coefficient

AC Base Maples 0.34 0.07

Memaloose 0.25 0.10

REQUIRED STRUCTURAL NUMBER

We used the procedures in the AASHTO guide to determine the required structural numbers in developing our rehabilitation strategies based on the ESALs listed in Table 4, the moduli listed in Table 5, and the other design parameters discussed next. Table 7 provides our recommendations for required structural numbers.

Table 7. Recommended Required Structural Number

Rest Area Location 20-Year Structural Number

Maples Drive/Truck 3.37

Car 1.71

Memaloose Drive/Truck 3.25

Car 1.41

OTHER DESIGN PARAMETERS

Other pavement design parameters used in our analysis are summarized below. These input parameters are recommended in the ODOT guide.

Reliability We used a reliability of 80 percent and 85 percent for the drive aisle and truck parking stalls at Maples and Memaloose, respectively, and 75 percent for the car parking stalls.

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Serviceability We used initial and terminal serviceability values of 4.2 and 2.5, respectively.

Overall Standard Deviation We used an overall standard deviation value of 0.49.

REHABILITATION RECOMMENDATIONS

OVERVIEW

Based on the results of our explorations, testing, and analyses, it is our opinion that the pavement can be rehabilitated by overlay for Maples and grind and inlay for Memaloose, provided the areas of moderate to severe fatigue are repaired prior to construction. Our specific recommendations for design and construction of the pavement are presented in the following sections. These should be incorporated into design and implemented during construction of the proposed development. The AC, aggregate base, stabilization aggregate, and subgrade geotextile recommended below should conform to the specifications presented in the “Materials” section.

PAVEMENT REPAIR

Prior to global rehabilitation, we recommend pavement repair of the moderate to severe distress listed below. Graphical representation of the distress data is provided on Figures 3 through 5.

The following repair items should be considered:

Repair area should be extended a minimum of 12 inches outside visible distress.

Maples repair:

Approximately 2,700 square feet of moderate to severe distress Approximately 45,400 square feet of pavement (assuming average 11-foot lane width) Over 6 percent of total pavement area

Memaloose – eastbound repair:

Approximately 4,200 square feet of moderate to severe distress Approximately 104,470 square feet of pavement (assuming average 10-foot lane width) Over 4 percent of total pavement area

Memaloose – westbound repair:

Approximately 2,950 square feet of moderate to severe distress Approximately 73,000 square feet of pavement Over 4 percent of total pavement area

Full-depth excavation and repair methodology must limit undermining of adjacent pavement.

Maples – Full-depth patching repair (below 3.0-inch-thick overlay)

3.0 inches of Level 3, ½-inch, dense asphalt concrete pavement (ACP) base course 10.0-inch-thick aggregate base Stabilization aggregate (as required) Subgrade geotextile

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Memaloose – Full-depth patching repair

2.0 inches of Level 3, ½-inch, dense ACP wearing course

5.0 inches of Level 3, ½-inch, dense ACP base course (two lifts) 10.0-inch-thick aggregate base Stabilization aggregate (as required) Subgrade geotextile

The actual thickness of the aggregate base will depend on the depth required to reach firm subgrade. Firm subgrade shall consist of undisturbed material that, based on proof rolling or foundation probing, indicates (at a minimum) medium stiff, fine-grained soil or medium dense, granular material. Proof rolling can result in extensive subgrade damage and should not be attempted if the subgrade consists of wet and sensitive, fine-grained soil. If wet and sensitive, fine-grained subgrade soil exists, subgrade evaluation should be performed by probing with a foundation probe rather than proof rolling. If deeper excavations are required due to unstable subgrade, stabilization material can be used as backfill below the design aggregate base section.

REHABILITATION

Maples Rest Area Following pavement repair, we recommend rehabilitation consisting of an overlay to increase pavement capacity. Based on our analysis for the traffic assumed, the pavement at Maples is below structural capacity by approximately 4.5 inches. However, due to the grade constraint, a 4.5-inch-thick overlay might not be possible. Therefore, we are recommending a 3.0-inch-thick overlay for a 10- to 15-year design life. Some isolated areas of fatigue will develop within 10 to 15 years in areas of high truck traffic and will likely need additional maintenance.

Overlay Rehabilitation – Maples

3.0 inches of ½-inch, Level 3, dense ACP (surface course)

Memaloose Rest Areas – Eastbound and Westbound Memaloose is at or near existing capacity based on the traffic analysis. We recommend grind and inlay rehabilitation to remove some of the surface distress. Note that in some truck stalls, localized rutting was observed in excess of 1.0 inch. In these locations, we recommend increasing the localized grind and inlay depth to 4.0 inches as noted below. We estimate approximately 2,500 square feet of deeper grinding may be required.

Grind and Inlay Rehabilitation – Memaloose 2.0-inch cold plane pavement removal

2.0 inches of Level 3, ½-inch, dense ACP (surface course)

Grind and Inlay Rehabilitation – Memaloose (truck parking, where necessary) 4.0-inch cold plane pavement removal

4.0 inches of Level 3, ½-inch, dense ACP (surface course)

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REST AREA STRUCTURES

Lightly loaded masonry structures will be installed or modified at the rest areas. Foundation loads for the structures were not provided at the time this report was prepared. We have assumed column loads less than 10 kips, continuous footing loads less than 3 kips per lineal foot, and floor loads less than 100 pounds per square foot (psf).

SLAB-ON-GRADE RECOMMENDATIONS

Satisfactory subgrade support for rest area structure floor slabs supporting up to 100 psf distributed areal loading can be obtained, provided the subgrade is cleared of organic material and other deleterious material. Slabs should be reinforced according to their proposed use and in accordance with the structural engineer’s recommendations. Load-bearing concrete slabs may be designed assuming a modulus of subgrade reaction, k, of 100 psi per inch.

We recommend a minimum 6-inch-thick layer of imported granular material be placed and compacted over the prepared soil subgrade. Imported granular material placed beneath floor slabs should meet the requirements for building slab base rock.

All slab subgrades should be evaluated by one of our geotechnical staff to confirm suitable bearing conditions. Observations should also confirm that loose or soft material, organic material, unsuitable fill, prior topsoil zones, and softened subgrades (if present) have been removed.

SHALLOW FOUNDATIONS

General Based on the results of our explorations, analysis, and anticipated light structural loads, the proposed structures can be supported by conventional spread footings bearing on firm, undisturbed soil. Foundations should not be established on undocumented fill, soft soil, or soil containing deleterious material. If present, this material should be removed and replaced with granular pads constructed using aggregate base, as defined in the “Materials” section. The imported granular material should be compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557, or until well-keyed, as determined by one of our geotechnical staff. We recommend a member of our geotechnical staff observe the prepared footing subgrade and the prepared granular pads.

Dimensions and Capacities Continuous wall and isolated spread footings should be at least 18 and 24 inches wide, respectively. The bottom of exterior footings should be at least 18 inches below the lowest adjacent exterior grade. The bottom of interior footings should be established at least 12 inches below the base of the slab.

Footings bearing on subgrade prepared as recommended above should be sized based on an allowable bearing pressure of 2,500 psf. This is a net bearing pressure; the weight of the footing and overlying backfill can be ignored in calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead plus long-term live loads and may be increased by one-third for short-term loads, such as those resulting from wind or seismic forces.

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Resistance to Sliding Lateral loads on footings can be resisted by passive earth pressure on the sides of the structure and by friction on the base of the footings. Our analysis indicates the available passive earth pressure for footings confined by native soil and structural fill is 300 pounds per cubic foot (pcf), modeled as an equivalent fluid pressure. Typically, the movement required to develop the available passive resistance may be relatively large; therefore, we recommend using a reduced passive equivalent fluid pressure of 250 pcf. Adjacent floor slabs, pavement, or the upper 12-inch depth of adjacent unpaved areas should not be considered when calculating passive resistance.

For footings in contact with native soil, a coefficient of friction equal to 0.30 may be used when calculating resistance to sliding. For footings in contact with the granular footing pads or native gravel, a coefficient of friction equal to 0.40 may be used when calculating resistance to sliding.

Settlement Based on the anticipated foundation loads, post-construction settlement of footings founded as recommended is anticipated to be less than 1 inch. Differential settlement between similarly loaded, newly constructed foundation elements should be approximately one-half of the total settlement over a distance of 50 feet.

Subgrade Observation All footing and floor subgrades should be evaluated by a representative of NV5 to evaluate bearing conditions. Observations should also confirm that all loose or soft material, organic material, unsuitable fill, prior topsoil zones, and softened subgrades (if present) have been removed. Localized deepening of footing excavations may be required to penetrate deleterious material.

Footing Construction Considerations If footing excavations are conducted during wet weather conditions (generally mid-October to mid-June), we recommend a minimum of 4 inches of granular material be placed and compacted until well keyed at the base of the excavations. The granular material reduces water softening of subgrade soil, reduces subgrade disturbance during placement of forms and reinforcement, and provides clean conditions for the reinforcing steel.

SITE SEISMIC CONSIDERATIONS

Seismic design for the rest area structures will be prescribed by ASCE 7-16. Based the anticipated presence of shallow basalt, we recommend that the Memaloose rest areas be classified as a seismic Site Class C. Explorations for the Maples rest area did not encounter bedrock and we did not observe bedrock outcrops in the site vicinity. Since we cannot verify that bedrock is present near the ground surface, we recommend that this site be classified as a seismic Site Class D. Seismic design criteria in accordance with ASCE 7-16 for the Maples and Memaloose rest areas are presented in Table 8 and 9, respectively.

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Table 8. Maples Rest Area – ASCE 7-16 Seismic Design Parameters

Parameter Short Period 1 Second

MCE Spectral Acceleration SS = 0.598 g S1 = 0.300 g

Site Class D

Site Coefficient Fa = 1.322 Fv = 2.0

Adjusted Spectral Acceleration SMS = 0.754 g SM1 = 0.600 g

Design Spectral Response Acceleration Parameters SDS = 0.502 g SD1 = 0.400 g g: gravitational acceleration (32.2 feet/second2) MCE: maximum considered earthquake

Table 9. Memaloose Rest Areas – ASCE 7-16 Seismic Design Parameters

Parameter Short Period 1 Second

MCE Spectral Acceleration SS = 0.482 g S1 = 0.223 g

Site Class C

Site Coefficient Fa = 1.3 Fv = 1.5

Adjusted Spectral Acceleration SMS = 0.626 g SM1 = 0.334 g

Design Spectral Response Acceleration Parameters SDS = 0.417 g SD1 = 0.223 g

MATERIALS

A submittal should be made for each material prior to the start of construction operations. Each submittal should include the test information necessary to evaluate the degree to which the material’s properties comply with the properties that were recommended or specified. The geotechnical engineer and other appropriate members of the design team should review each submittal.

STRUCTURAL FILL

Structural fill includes fill beneath foundations, slabs, pavement, any other areas intended to support structures, or within the influence zones of structures. Structural fill should be free of organic material and other deleterious material and, in general, should consist of particles no larger than 4 inches in diameter. A brief characterization of some of the acceptable materials and our recommendations for their use as structural fill are provided below.

On-Site Soil The near-surface soil at the site is primarily fine grained. This soil can be used for structural fill, provided it can be adequately moisture conditioned and meets the specifications provided in

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Oregon Standard Specifications for Construction – 2021 (OSSC) 00330.12 (Borrow Material).

The site soil is sensitive to small changes in moisture content and highly susceptible to disturbance when wet. Use of the on-site material as structural fill will not be possible during the wet season, which typically extends from mid-October to mid-June.

We estimate the optimum moisture content for compaction to be approximately 13 to 20 percent for the on-site soil. Optimum compaction typically occurs within 3 percent of optimum moisture.

Typically, the moisture content for the on-site soil will be greater than the anticipated optimum moisture content required for adequate compaction. It is likely that even during the dry season, drying will be required to achieve adequate compaction. We recommend using imported granular material for structural fill if the on-site material cannot be properly moisture conditioned.

When used as structural fill, the on-site soil should be placed in lifts with a maximum uncompacted thickness of 6 to 8 inches. The fine-grained soil should be compacted to not less than 92 percent of the maximum dry density, as determined by ASTM D1557. The coarse-grained soil should be compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557.

Imported Granular Material Imported granular material used for structural fill should be pit- or quarry-run rock, crushed rock, or crushed gravel and sand and should meet the specifications provided in OSSC 00330.14 (Selected Granular Backfill) or OSSC 00330.15 (Selected Stone Backfill). Imported granular material should be fairly well graded between coarse and fine material, should have less than 5 percent by dry weight passing the U.S. Standard No. 200 sieve, and should have at least two mechanically fractured faces. Material with a higher fines content is permissible, provided compaction can be achieved.

When used as structural fill, imported granular material should be placed in lifts with a maximum uncompacted thickness of 12 inches and compacted to not less than 95 percent of the maximum dry density, as determined by ASTM D1557. Imported granular material should be placed in accordance with OSSC 00596B.47 (Backfill Placement).

AC

The AC should be Level 3, ½-inch, dense ACP according to OSSC 00744 (Asphalt Concrete Pavement). Minimum and maximum lift thicknesses are 2.0 and 3.0 inches for ½-inch ACP, respectively. An adjustment to lift thicknesses outside this range should be reviewed by both NV5 and TIC. Asphalt binder should be performance graded. For Level 3 ACP with static truck loads, we recommend PG 70-22 binder; however, the binder grade should be adjusted depending on the aggregate gradation and amount of reclaimed asphalt pavement and/or recycled asphalt shingles in the contractor’s mix design submittal.

Aggregate Base Imported granular material used as aggregate base should be clean, crushed rock or crushed gravel and sand that are dense graded. The aggregate base should meet the gradation defined in OSSC 00641 (Aggregate Subbase, Base, and Shoulders), with the exception that the

15 OregonTIC-3-01:100521 aggregate has less than 5 percent by dry weight passing the U.S. Standard No. 200 sieve, a maximum particle size of 1½ inches, and at least two mechanically fractured faces. The aggregate base should be compacted to not less than 95 percent of the maximum dry density, as determined by AASHTO T 99.

Stabilization Material Stabilization material should consist of pit- or quarry-run rock, crushed rock, or crushed gravel and sand and should meet the requirements set forth in OSSC 00330.14 (Selected Granular Backfill) and OSSC 00330.15 (Selected Stone Backfill), with a maximum particle size of 3 inches for selected granular backfill and 6 inches for selected stone backfill, less than 5 percent by dry weight passing the U.S. Standard No. 4 sieve, and at least two mechanically fractured faces. The material should be free of organic material and other deleterious materials. Stabilization material should be placed over a geotextile fabric in one lift and compacted to a firm condition.

Subgrade Geotextile The subgrade geotextile should conform to OSSC 00350 (Geosynthetic Installation). A minimum initial aggregate base lift of 6 inches is required over geotextiles.

OBSERVATION OF CONSTRUCTION

Satisfactory earthwork and pavement performance depend to a large degree on the quality of construction. Sufficient observation of the contractor's activities is a key part of determining that the work is completed in accordance with the construction drawings and specifications.

Subsurface conditions observed during construction should be compared with those encountered during the subsurface explorations. Recognition of changed conditions often requires experience; therefore, qualified personnel should visit the site with sufficient frequency to determine if subsurface conditions change significantly from those anticipated.

LIMITATIONS

We have prepared this report for use by the Oregon Travel Information Council and the design and construction team for the proposed project. The report can be used for bidding or estimating purposes, but our report, conclusions, and interpretations should not be construed as warranty of the subsurface conditions and are not applicable to other sites.

Exploration observations indicate soil conditions and pavement conditions only at specific locations and only to the depths penetrated. They do not necessarily reflect soil strata, pavement, or water level variations that may exist between exploration locations. If subsurface conditions differing from those described are noted during the course of excavation and construction, re-evaluation will be necessary.

The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in this report for consideration in design.

16 OregonTIC-3-01:100521

Within the limitations of scope, schedule, and budget, our services have been executed in accordance with generally accepted practices in this area at the time this report was prepared.

No warranty, express or implied, should be understood.

We appreciate the opportunity to be of continued service to you. Please call if you have questions concerning this report or if we can provide additional services.

Sincerely, NV5

Shashwath Sreedhar, Ph.D., E.I.T.

Geotechnical Staff

Krey D. Younger, P.E., G.E.

Principal Engineer

SS:TAP:KDY:kt

Attachments

One copy submitted (via email only)

Document ID: OregonTIC-3-01-100521-geolr.docx

© 2021 NV5. All rights reserved.

FIGURES

VICINITY MAP BASED ON AERIAL

PHOTOGRAPH OBTAINED FROM

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MAPLES AND MEMALOOSE REST AREAS

MARION COUNTY, OR

OREGONTIC-3-01

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MAPLES AND MEMALOOSE REST AREAS

WASCO COUNTY, OR

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NOTES:

1. SITE PLAN BASED ON DRAWING OBTAINED FROM

KITTELSON & ASSOCIATES, INC.

2. AERIAL PHOTOGRAPH OBTAINED FROM GOOGLE

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NOTES:

1. SITE PLAN BASED ON DRAWING OBTAINED FROM

KITTELSON & ASSOCIATES, INC.

2. AERIAL PHOTOGRAPH OBTAINED FROM GOOGLE

EARTH PRO JULY 2, 2021.

LEGEND:

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NOTES:

1. SITE PLAN BASED ON DRAWING OBTAINED FROM

KITTELSON & ASSOCIATES, INC.

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ATTACHMENT A

A-1 OregonTIC-3-01:100521

ATTACHMENTS A THROUGH C

FIELD EXPLORATIONS

GENERAL

We explored the existing pavement conditions at the rest areas by drilling 12 pavement borings and explored subgrade conditions for the proposed masonry structure at each rest area by drilling 3 borings. The locations of these explorations are shown on Figures 3 through 5. The borings were completed by Dan J. Fischer Excavating, Inc. of Forest Grove, Oregon, on June 28 and 29, 2021, under the supervision of NV5 personnel. The pavement cores were recovered using a portable core drill with a 5-inch-diameter, diamond core barrel, and the borings were drilled with a 4-inch-diameter, solid-stem auger. The pavement cores were filled with polymer-modified cold-patch asphalt and borings were filled with bentonite chips. The exploration logs are presented in the following attachments:

Attachment A: Maples rest area – four pavement borings, one subgrade boring Attachment B: Memaloose rest area– eastbound – four pavement borings, one subgrade boring Attachment C: Memaloose rest area– westbound – four pavement borings, one subgrade boring

SOIL SAMPLING

We collected representative samples of the various soils encountered in the borings for geotechnical laboratory testing. Samples were collected from the borings using 1½-inch-inside diameter, split-spoon sampler (SPT). The split-spoon sampling was conducted in general accordance with ASTM D1586. The split-spoon samplers were driven into the soil with a 140-pound hammer free falling 30 inches. The samplers were driven a total distance of 18 inches. The number of blows required to drive the sampler the final 12 inches is recorded in the exploration logs, unless otherwise noted. Representative grab samples of the soil were collected from the auger cuttings. Sampling methods and intervals are shown on the exploration logs.

The hammer used to conduct the SPTs was lifted using a rope and cathead system. The hammer was raised using two wraps of the rope around the cathead to conduct the SPTs.

SOIL CLASSIFICATION

The soil samples were classified in accordance with the “Exploration Key” (Table A-1) and “Soil Classification System” (Table A-2), which are presented in this attachment. The exploration logs indicate the depths at which the soil or its characteristics change, although the change actually could be gradual. Classifications are shown on the exploration logs.

A-2 OregonTIC-3-01:100521

LABORATORY TESTING

MOISTURE CONTENT

We tested the natural moisture content of select soil samples in general accordance with ASTM D2216. The natural moisture content is a ratio of the weight of the water to soil in a test sample and is expressed as a percentage. The test results are presented Attachments A through C.

A-3 OregonTIC-3-01:100521

ATTACHMENT A

MAPLES REST AREA

We completed four pavement borings (C-1 through C-4) and one subgrade boring (B-1). The exploration locations are shown on Figure 3.

SYMBOL SAMPLING DESCRIPTION

Location of sample collected in general accordance with ASTM D1586 using Standard Penetration Test (SPT) with recovery

Location of sample collected using thin-wall Shelby tube or Geoprobe® sampler in general accordance with ASTM D1587 with recovery

Location of sample collected using Dames & Moore sampler and 300-pound hammer or pushed with recovery

Location of sample collected using Dames & Moore sampler and 140-pound hammer or pushed with recovery

Location of sample collected using 3-inch-outside diameter California split-spoon sampler and 140-pound hammer with recovery

Location of grab sample

Rock coring interval

Water level during drilling

Water level taken on date shown

GEOTECHNICAL TESTING EXPLANATIONS

ATT

CBR

CON

DD

DS

HYD

MC

MD

NP

OC

Atterberg Limits

California Bearing Ratio

Consolidation

Dry Density Direct Shear

Hydrometer Gradation

Moisture Content Moisture-Density Relationship

Non-Plastic

Organic Content

P

PP

P200

RES

SIEV

TOR

UC

VS

kPa

Pushed Sample

Pocket Penetrometer

Percent Passing U.S. Standard No. 200 Sieve

Resilient Modulus

Sieve Gradation Torvane

Unconfined Compressive Strength

Vane Shear Kilopascal

ENVIRONMENTAL TESTING EXPLANATIONS

CA

P

PID

ppm

Sample Submitted for Chemical Analysis

Pushed Sample

Photoionization Detector Headspace Analysis

Parts per Million

ND

NS

SS

MS

HS

Not Detected

No Visible Sheen

Slight Sheen

Moderate Sheen Heavy Sheen

EXPLORATION KEY TABLE A-1

Graphic Log of Soil and Rock Types

Inferred contact between soil or rock units (at approximate depths indicated)

Observed contact between soil or rock units (at depth indicated)

RELATIVE DENSITY - COARSE-GRAINED SOIL

Relative Density

Standard Penetration Test (SPT) Resistance

Dames & Moore Sampler (140-pound hammer)

Dames & Moore Sampler (300-pound hammer)

Very loose 0 – 4 0 – 11 0 – 4 Loose 4 – 10 11 – 26 4 – 10

Medium dense 10 – 30 26 – 74 10 – 30 Dense 30 – 50 74 – 120 30 – 47

Very dense More than 50 More than 120 More than 47

CONSISTENCY - FINE-GRAINED SOIL

Consistency Standard

Penetration Test (SPT) Resistance

Dames & Moore Sampler

(140-pound hammer)

Dames & Moore Sampler

(300-pound hammer)

Unconfined Compressive Strength

(tsf) Very soft Less than 2 Less than 3 Less than 2 Less than 0.25

Soft 2 – 4 3 – 6 2 – 5 0.25 – 0.50 Medium stiff 4 – 8 6 – 12 5 – 9 0.50 – 1.0

Stiff 8 – 15 12 – 25 9 – 19 1.0 – 2.0 Very stiff 15 – 30 25 – 65 19 – 31 2.0 – 4.0

Hard More than 30 More than 65 More than 31 More than 4.0

PRIMARY SOIL DIVISIONS GROUP SYMBOL GROUP NAME

COARSE-

GRAINED SOIL

(more than

50% retained on

No. 200 sieve)

GRAVEL

(more than 50% of coarse fraction retained on No. 4 sieve)

CLEAN GRAVEL

(< 5% fines) GW or GP GRAVEL

GRAVEL WITH FINES

(≥ 5% and ≤ 12% fines)

GW-GM or GP-GM GRAVEL with silt GW-GC or GP-GC GRAVEL with clay

GRAVEL WITH FINES

(> 12% fines)

GM silty GRAVEL GC clayey GRAVEL

GC-GM silty, clayey GRAVEL

SAND

(50% or more of coarse fraction passing No. 4 sieve)

CLEAN SAND

(<5% fines) SW or SP SAND

SAND WITH FINES

(≥ 5% and ≤ 12% fines)

SW-SM or SP-SM SAND with silt SW-SC or SP-SC SAND with clay

SAND WITH FINES

(> 12% fines)

SM silty SAND SC clayey SAND

SC-SM silty, clayey SAND

FINE-GRAINED

SOIL

(50% or more passing No. 200 sieve)

SILT AND CLAY

Liquid limit less than 50

ML SILT

CL CLAY

CL-ML silty CLAY OL ORGANIC SILT or ORGANIC CLAY

Liquid limit 50 or greater

MH SILT

CH CLAY

OH ORGANIC SILT or ORGANIC CLAY

HIGHLY ORGANIC SOIL PT PEAT

MOISTURE CLASSIFICATION ADDITIONAL CONSTITUENTS

Term Field Test Secondary granular components or other materials such as organics, man-made debris, etc.

Percent

Silt and Clay In:

Percent

Sand and Gravel In:

dry…