Foundation Engineering, Inc. · 9/29/2016 · meter (ASTM G57). The resistivity test was located west of BH-2. The approximate location is identified as R-1 on Figure 2A. The 4-pin

820 NW Cornell Avenue • Corvallis, Oregon 97330 • 541-757-7645

7587 SW Cirrus Drive, Bldg 24 • Beaverton, Oregon 97008 • 503-643-1541

Foundation Engineering, Inc. Professional Geotechnical Services

Steve Hodge, P.E. September 29, 2016

County Engineer

Lincoln County Public Works

880 NE 7th Street

Newport, Oregon 97365

Eckman Creek Culvert Replacement Project 2161081

Foundation Report

Lincoln County, Oregon

Dear Mr. Hodge:

We have completed the requested geotechnical investigation for the

above-referenced project in Lincoln County, Oregon. This report provides a

description of our work, a discussion of the site conditions, and recommendations

for the design and construction of shallow foundations.

BACKGROUND

Lincoln County plans to replace the culvert crossing Eckman Creek at MP 1.03 on East

Eckman Creek Road in Waldport, Oregon. The site location is shown on Figure 1A

(Appendix A).

The existing 12-foot diameter culvert became blocked by debris following a series of

severe winter storms in mid to late December 2015. Rising water eventually

overtopped the road and washed out a portion of the Eckman Road embankment.

The County installed a temporary bypass pipe and added rip rap to the face of the

embankment. Eckman Road provides the only paved access to two quarries,

residential homes, the City of Waldport’s portable water intake, and forest timber

lands.

Preliminary drawings provided by the County indicate a 30-foot long, precast concrete,

arch open-bottom culvert is planned that will be supported on continuous spread

footings. The drawings also show 8-foot wide wing walls at the ends of the culvert

to retain new approach fill.

Lincoln County is the project owner. The County retained Foundation Engineering, Inc.

to complete a geotechnical investigation for the replacement culvert. Our scope of

work was outlined in a proposal dated August 18, 2016, and authorized by a signed

agreement dated August 24, 2016.

Eckman Creek Culvert Replacement September 29, 2016

Foundation Report 2 Project 2161081

Lincoln County, Oregon Lincoln County Public Works

EXPLORATION

Two exploratory borings (BH-1 and BH-2) were drilled on September 9, 2016, using

a CME 75, truck-mounted drill rig and mud-rotary drilling techniques. BH-1 was

drilled in the north-bound lane, ±25 feet north of the outside edge of the existing

culvert. BH-2 was drilled in the same lane, ±43 feet south of the edge of the

culvert. The approximate boring locations are shown on Figure 2A (Appendix A).

BH-1 extended to a depth of ±25.1 feet and BH-2 extended to ±31.5 feet.

Samples were obtained at 2.5-foot intervals to a depth of ±20 feet and at 5-foot

intervals thereafter. Disturbed samples were obtained with a split-spoon in

conjunction with the Standard Penetration Test (SPT). The SPT provides an

indication of the relative stiffness or density of the foundation soils.

The borings were continually logged during drilling. The final logs (Appendix B)

were prepared based on a review of the field logs, laboratory testing, and an

examination of the soil samples in our office. The sampling depths and SPT data

for each boring are summarized on the logs (Appendix B).

SURFACE AND SUBSURFACE CONDITIONS

Surface Conditions

The road runs approximately north-south. Topographic information provided by

Lincoln County indicates the road surface at the culvert crossing (±Sta. 3+00) lies

at El. 118.88. The ground surface east of the culvert slopes to ±El. 103.8. The

low point to the west lies at ±El. 106.5.

Subsurface Conditions

A brief discussion of the subsurface conditions is provided below. More detailed

soil and rock descriptions are provided on the boring logs in Appendix B.

BH-1 (North Side). The pavement section at BH-1 consists of 6 inches of asphalt

concrete (AC) over ±9 inches of ¾-inch minus, dense, angular, crushed rock (base

rock). The pavement section is underlain by fill consisting of dense silty gravel to

±5 feet, medium stiff to stiff silt with some sand and gravel to ±10 feet, and

medium stiff silty clay with trace sand and gravel and scattered organics to

±12.5 feet. SPT N-values ranged from 7 to 11 blows per foot (bpf) within the fill.

The fill is underlain by loose silty sand from ±12.5 to 17.5 feet. N-values of 5 and

11 were recorded in this strata. Dense silty gravel was encountered from ±17.5

to 20 feet. Residual soil was encountered at ±20 feet. Residual soil is bedrock

that has decomposed in place to the consistency of soil. The residual soil consists

of very dense silty rock fragments. A relict rock texture from the underlying

formation was apparent in the residual soil.




Grey, slightly weathered, very weak to weak (R1 to R2) basalt (Basalt of Yachats)

was encountered at ±24 feet. Practical sampling refusal (N>100) was recorded in

the basalt at 25.1 feet, the limits of our exploration.

BH-2 (South Side). The pavement section at BH-2 consisted of 6 inches of AC over

±9 inches of base rock. The pavement section is underlain by fill to ±10 feet.

The fill consists of dense silty gravel with trace sand to ±5 feet and dense silty sand

with trace gravel to ±10 feet. N-values in the fill ranged from 31 to 47.

Alluvium consisting of alternating layers of medium dense silty sand, soft clayey silt,

and loose silty sand was encountered to ±17.5 feet. N-values ranging from 3 to

16 were recorded in these layers. Gravel with some sand and silt follows to

±28 feet. The gravel was medium dense to ±20 feet and very dense from ±20

to 28 feet. Scattered cobbles up to 6 inches in diameter were noted between ±20

and 28 feet. Medium dense silty sand was encountered from ±28 to 31.5 feet,

the limits of our exploration. An N-value of 21 was recorded in the sand.

Ground Water

The use of mud-rotary drilling during exploration precluded the direct observation of

ground water levels in the borings at the time of the investigation. It would be

reasonable to assume the ground water levels beneath the road fluctuate seasonally

and approximately follow the creek level.

PROPOSED REPLACEMENT STRUCTURE

Drawings provided by Lincoln County indicate the culvert is to be replaced by a

Conspan O Series 0430 precast concrete arch bridge manufactured by Contech

Engineered Solutions LLC. The structure will have a height of 9.3 feet, a 30-foot span,

and an out-to-out width of 40 feet. The ends of the structure will have 8-foot long

wingwalls. An elevation of the outlet end shows the flowline of the structure will be

±14 feet below the road surface. We estimate the bottom of the footings supporting

the arch segments will extend a nominal 16 feet below the road surface.

HYDRAULICS/SCOUR

A hydraulic/scour study had not been completed at the time this report was prepared.

The County indicated the normal flows in the creek are relatively low. Also, there

is a culvert just upstream at the City’s water intake that limits the flow under

Eckman Road. The County reported that, based on conversations with the Oregon

Department of Fish and Wildlife, the culvert replacement structure must be one and

a half times the stream width, requiring a 30-foot span. An open-bottom arch

culvert was selected to meet this criterion.

FIELD AND LABORATORY TESTING

The laboratory testing included natural water contents and percent fines. Those

test results are summarized in Table 1C (Appendix C). The water contents are also

included on the boring logs (Appendix B).




In-situ resistivity testing was completed using a Nilsson 400, 4-pin, soil resistance

meter (ASTM G57). The resistivity test was located west of BH-2. The

approximate location is identified as R-1 on Figure 2A.

The 4-pin resistance meter provides an estimate of the average resistivity of a soil

profile extending to a depth equal to the spacing between the pins. The tests were

performed with the pins spaced at ±6, 9, and 12 feet. The resistivity values,

summarized in Table 2C (Appendix C), ranged from ±12,064 to 21,831 ohm-cm,

which are consistent with the presence of predominantly granular soils.

pH tests (ASTM G51) were completed on samples SS-1-4 from ±10 to 11.5 feet

and on SS-2-5 from ±12.5 to 14 feet. The results, summarized in Table 3C,

indicate pH values ranging from 5.8 to 5.9 (i.e., moderately acidic).

SEISMIC ANALYSIS AND EVALUATION

Bedrock Acceleration and Site Response

Culverts are often not designed for seismic loads. However, if seismic design is

required, we assume the culvert will be designed similar to a bridge in accordance

with the 2014 AASHTO LRFD Bridge Design Specifications. AASHTO (2014)

recommends all bridge structures be designed using earthquake ground motions

having a 1,000-year average return period. A response spectrum for the site was

established using the General Procedure in AASHTO (2014) Section 3.10 and seismic

design maps based on the USGS National Seismic Hazard Maps (2002). Based on

the anticipated depth of the new footings and the recommended site preparation, we

concluded the average subsurface conditions across the site correspond to an

AASHTO Site Class C. The AASHTO General Procedure Response Spectrum

established for a Site Class C are shown on Figure 3A (Appendix A).

Liquefaction, Settlement, and Lateral Spread

Liquefiable soils typically consist of loose sands and non-plastic silts below the

ground water table. The site is underlain by site fill consisting of predominantly

dense granular soils or stiff fine-grained soil, followed by predominantly dense

gravels. Bedrock was encountered at 24 feet in BH-1. Drilling was discontinued

at BH-2 at ±31.5 feet before bedrock was encountered. However, we anticipate

bedrock underlies the south side of the crossing at a relatively shallow depth below

the bottom of BH-2.

A ±4 to 5-foot thick layer of sand was encountered at BH-1 between the

embankment fill and the underlying dense gravels. An N-value of 5 was recorded

at a depth of ±12 to 13 feet, indicating the sand is loose. This layer is potentially

liquefiable during a large, long-duration seismic event. New footings for the

replacement structure will extend below most of the sand. Furthermore, we have

recommended herein that any sand remaining beneath the footings be removed and

replaced with compacted structural fill. As a result, new footings will bear on




relatively dense gravel extending to at least ±28 feet, or underlain bedrock.

Therefore, the risk of liquefaction and liquefaction-induces settlement will be

mitigated by the recommended site preparation for the new foundations.

Construction of the replacement structure will require a relatively large excavation

which will be backfilled with granular fill. Therefore, the risk of settlement and

lateral spread is low in the backfill zone. There is potential for loose sand to remain

beneath the existing road embankments outside the backfill zone. Therefore, lateral

spread could occur in portions of the approaches. We anticipate it will be most

practical to repair damages to the approaches due to liquefaction and lateral spread

(if needed), following an earthquake.

FOUNDATION ANALYSIS AND RECOMMENDATIONS FOR DESIGN AND

CONSTRUCTION

Anticipated Footings

The County would like to use precast continuous footings to support the replacement

structure. Drawings available on-line at the Contech website for the Series

O structure indicate the precast footing units are placed in segments on a thin

bedding of granular material and then filled with cast-in-place concrete.

Foundation Design and Construction

Bearing Resistance. If the foundation areas are prepared as specified in this report,

new footings will bear on a layer of compacted crushed rock followed by medium

dense to very dense alluvial gravel. The Contech technical literature indicates a

required bearing capacity of 4,000 psf for footing design. We assume this value

represents a working or allowable bearing pressure (based on ASD design). We

believe an allowable bearing pressure (ASD) of 4,000 psf is reasonable for the

anticipated material beneath the new footings. The allowable value typically

includes a factor of safety of 3 (i.e., an ultimate bearing capacity of 12,000 psf).

For Load Factor Resistance Design (LRFD), this nominal value corresponds to a

factored bearing pressure of 5,400 psf (assuming an LRFD resistance factor of 0.45).

For foundation design, we have assumed any remaining loose or soft soil will be

removed from the footing trenches and be replaced with compacted granular fill.

We recommend the footing trenches extend to dense gravel and backfilled with

granular fill. The granular fill should consist of crushed aggregate meeting the

requirements of ODOT Section 02630.10 Dense Graded Aggregate. We

recommend using material meeting the gradation of 1½’’-0, 1’’-0 or ¾’’-0 in

Table 02630-1. These gradations should allow field density testing.

The trenches should be at least 12 inches wider than the dimensions of the precast

footing units. All loose sand, disturbed soil, or clods should be removed from the

footing trenches prior to backfilling. The trench backfill should be placed in lifts and

compacted to at least 95% relative compaction (according to the maximum dry

density of ASTM D698 or AASHTO T-99).




Settlement. The footings will be underlain by predominately dense granular soil,

followed by bedrock. For purposes of design, we recommend assuming foundation

settlement in the range of ±½ to 1 inch. It is anticipated the settlement will occur

during construction as the foundations are loaded.

Lateral Resistance. We recommend using a coefficient of friction of 0.5 to evaluate

the sliding resistance between the base of the footings and the granular fill. The

sides of the footings will likely bear against compacted backfill comprised of angular

crushed rock. Assuming these conditions, we recommend calculating the nominal

passive resistance on the sides of the footings using an equivalent fluid density of

435 pcf. This value is based on a unit weight of 125 pcf and a passive earth

pressure coefficient (Kp) of 3.5. The passive resistance may be combined with the

sliding resistance at the base of the footings.

Wing Walls

Wing walls will retain the fill at the ends of the structure. Contech drawings indicate

the wing walls will be ±8 feet long and ±13.9 feet deep at the connection to the

spans, tapering to ±11.9 feet away from the structure.

The foundation design and construction recommendations provided above for the

culvert footings are also applicable to the retaining wall footings.

We calculated design earth pressures for the wall based on active conditions,

assuming the top of the wall will be unrestrained and allowed to rotate or translate

at least 0.002H at the time of backfilling (where H is the height of the wall).

A friction angle of 34 degrees and a unit weight of 125 pcf were assumed for the

backfill. Where the backfill has a level backslope, walls should be designed using

an active earth pressure coefficient (ka) 0.28 and an equivalent fluid density of

35 pcf. Where 2(H):1(V) backfill slopes are used, the walls should be designed

using a ka of 0.42 and an equivalent fluid density of 52 pcf.

Traffic surcharge loads should be assumed where the top of the wall will be within

±10 feet of the roadway. The AASHTO Bridge Design Specifications Manual

(2012) recommends estimating the traffic loads applied to the top of the walls parallel

to traffic using an equivalent soil surcharge with a minimum height of 2 feet. The

minimum surcharge height corresponds to a uniform surcharge pressure of

±250 psf. This results in an additional uniform lateral pressure of ±105 psf for

active conditions with a coefficient ka of 0.42 (sloping backfill).

Structural Backfill

Contech Technical Bulletin No. 4 provides specific recommendations for structural

backfill. They recommend a minimum structural backfill width of 6 feet for the

larger span structures. Tables 1 and 2 of the technical bulletin also provide

minimum requirements for the backfill material. The gradations listed in the tables

allow between 15 and 35% material passing the No. 200 sieve. Because of the




possibility of ground water, material containing relatively high amounts of fines may

have significant problems during placement. Instead, we recommend using ¾’’-0

crushed rock meeting the requirements of ODOT Section 02630.10 Dense Graded

Aggregate, Table 02630-1. The nearby quarries should be able to provide this

material with minimum haul distance.

Contech also provides recommendations for placing and compacting the structural

backfill to avoid unbalanced lateral loads. Those recommendations should be

incorporated in the project drawings and specifications. However, we do not

recommend using the “modified Proctor” specification (i.e., ASTM D1557 or

AASHTO T-180) for compaction.

APPROACHES AND EMBANKMENTS

Approach Construction

The approaches will be reconstructed after the culverts are built. The earthwork

should be completed with stripping, grubbing, benching, and fill placement done in

accordance with ODOT Section 00330 – Earthwork.

The road embankment at the approaches (i.e., outside of the 6-foot minimum

structural backfill zone) can be constructed with a wide variety of materials. Due

to the proximity of existing quarries, we anticipate crushed rock may be a

cost-effective approach fill. Such material is also relatively easy to place and

compact. The rock could consist of any of the materials specified in Table 02630-1,

including 2½’’-0 and 2’’-0 rock. Other materials could be considered as approach

fill, if approved by Foundation Engineering.

Granular fill typically compacts most efficiently using a smooth-drum vibratory roller

or a vibratory hoe pack. Embankment fill compacted using this equipment should

be placed in lifts ±1 foot thick or less. We recommend using light compaction

equipment (e.g., a jumping jack or plate compactor) within the controlled backfill

zone. Where light compaction equipment is used, the fill should be placed in thinner

lifts (6 inches or less).

Approach Settlement

The approaches are underlain by predominantly medium dense to dense gravels and

stiff fine-grained soil over shallow bedrock. These materials should have relatively

low compressibility. The finished grades will approximately match the existing

grades. With proper compaction of the approach fill, limited post-construction

approach settlement is anticipated.




CONSTRUCTION RECOMMENDATIONS

Specifications

We have assumed earthwork and fill material specifications for this project will

reference the Oregon Department of Transportation “Oregon Standard Specifications

for Construction (ODOT, 2015).

Seasonal Issues

Construction of the new culverts will require deep excavations including trenching

below the creek bed for the foundations. Construction during the dry summer

months (typically late June through the end of September) is recommended to reduce

dewatering requirements and the risk of sidewall caving and raveling. We

understand construction is scheduled to begin in July of next year. Therefore, the

work will be completed during dry weather.

Excavations/Shoring/Dewatering/Fill Slopes

The footings are expected to extend ±16 feet below the current road surface.

Therefore, we estimate footing excavations up to ±18 feet below the road surface

will be required for the footing trenches and removal of soft or loose soil. The

excavations should be laid back, benched or shored in accordance with Oregon OSHA

standards (OR OSHA, 2011).

We anticipate the excavations will be a layered profile that includes gravel, sand, silt,

and clay. Most of these materials are consistent with OR OSHA Type B soil based

on their observed stiffness or density. The loose silty sand layer encountered from

±12.5 to 17.5 feet in BH-2 corresponds to a Type C soil. OR OSHA recommends

a maximum cut slope of 1(H):1(V) for Type B soil and 1.5(H):1(V) for Type C soil.

This cut slope should be adjusted, as needed, if raveling or seepage are observed.

Where loose sand is encountered we recommend flattening the cut slope to

2(H):1(V). The appropriate cut slopes will need to be verified at the time of

construction. It is the contractor’s responsibility to maintain stable cut slopes and

to provide the necessary shoring.

Construction of the foundations will require excavations extending below the creek

bed. Ground water levels are not currently known, but are expected to reflect creek

levels and, therefore, will fluctuate seasonally. A temporary culvert could be placed

in the creek bed to transport most of the water through the work zone. However,

because the soils below the creek bed are relatively permeable, it should be assumed

ground water will still infiltrate into the footing excavations and dewatering will be

required.

Details of embankment construction are not available. We have assumed new

slopes will be constructed to match existing ones. We anticipate the embankments

will be constructed using predominantly imported granular fill. We also recommend

that any slopes exposed to creek water be protected from scour or erosion with

imported riprap.




LIMITATIONS

Construction Observation/Testing

We recommended a Foundation Engineering representative be present during

construction to observe the foundation conditions for the continuous footings and

confirm the material is consistent with the design assumptions. Any geotechnical

engineering judgment in the field should be provided by a Foundation Engineering

representative.

We anticipate the gradation of the recommended structural backfill and the granular

fill beneath footings will allow field density testing to monitor compaction.

Approach fills, however, may consist of materials that are too coarse for density

testing. Adequate compaction of this material will need to be evaluated by

observation of the compaction method and periodic proof-rolls using a loaded dump

truck or other approved heavy construction vehicle.

VARIATION OF SUBSURFACE CONDITIONS, USE OF THIS INFORMATION AND

WARRANTY

The analysis, conclusions, and recommendations contained herein assume the

subsurface profiles encountered in the borings are representative of the overall site

conditions. The above recommendations assume we will have the opportunity to

review final drawings and be present during construction to confirm the assumed

foundation conditions. No changes in the enclosed recommendations should be

made 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 Lincoln County Public Works and

their design consultants for the Eckman Creek Culvert Replacement project in Lincoln

County, 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. It is assumed 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.




REFERENCES

American Association of State Highway and Transportation Officials (AASHTO),

2012, AASHTO LRFD Bridge Design Specifications.

FHWA, 2003, Standard Specifications for Construction of Roads and Bridges on

Federal Highway Projects: Federal Highway Administration Federal Lands

Highway (FHWA-FLD), Publication No. FHWA-FLH-03-002.

ODOT, 2015, Oregon Standard Specifications for Construction: Oregon Department

of Transportation (ODOT).

OR OSHA, 2011, Oregon Occupational Safety and Health Standards, Oregon

Administrative Rules, Chapter 437, Division 3 - Construction: Oregon

Occupational Safety and Health Administration (OR OSHA).

USGS, 2002, National Seismic Hazard Maps: U.S. Geological Survey (USGS),

http://eqhazmaps.usgs.gov.

Appendix A

Figures

Professional Geotechnical Services

Foundation Engineering, Inc.

4,0002,0001,000

SCALE IN FEET

0

SITE

2161081

AutoCAD SHX Text

FIGURE NO.

AutoCAD SHX Text

PROJECT NO.

AutoCAD SHX Text

REVIS.

AutoCAD SHX Text

DWN.

AutoCAD SHX Text

APPR.

AutoCAD SHX Text

DATE

AutoCAD SHX Text

FILE NAME:

AutoCAD SHX Text

820 NW CORNELL AVENUE

AutoCAD SHX Text

BUS. (541) 757-7645 FAX (541) 757-7650

AutoCAD SHX Text

CORVALLIS, OR 97330-4517

AutoCAD SHX Text

FOUNDATION ENGINEERING INC.

AutoCAD SHX Text

PROFESSIONAL GEOTECHNICAL SERVICES

AutoCAD SHX Text

VICINITY MAP

AutoCAD SHX Text

ECKMAN CREEK CULVERT REPLACEMENT

AutoCAD SHX Text

LINCOLN COUNTY, OREGON

AutoCAD SHX Text

1A

AutoCAD SHX Text

AUG. 2016

AutoCAD SHX Text

mdm

AutoCAD SHX Text

Fig1A

Notes:1. The Design Response Spectrum is based on AASHTO 2014 Section 3.10.3 using the

following parameters:Site Class= C Damping = 5%

1,000-yr. PGA = 0.43 Fpga = 1.00 As = 0.43SS = 1.02 Fa = 1.00 SDS = 1.02S1 = 0.47 Fv = 1.33 SD1 = 0.62

2. PGA, SS and S1 values are based on USGS 2002 maps and information from the USGSwebsite. The 1,000-yr. values assume 7% probability of exceedence in 75 years.

3. Fpga, Fa and Fv were established based on AASHTO 2014, Tables 3.10.3.2-1, 3.10.3.2-2 and3.10.3.2-3 using the selected PGA, Ss and S1 values.

4. Site location: lattitude 44.3997, longitude -124.0310.

FIGURE 3AAASHTO 2014 GENERAL PROCEDURE RESPONSE SPECTRA

Eckman Creek Culvert ReplacementLincoln County, Oregon

Project No. 2161081

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.10

0 0.5 1 1.5 2 2.5 3

Elas

tic S

eism

ic C

oeffi

cien

t, C

sm(g

)

Period (seconds)

1,000-yr. Response Spectrum

Appendix B

Boring Logs

Professional Geotechnical Services


ASPHALTIC CONCRETE (±6 inches).Dense CRUSHED ROCK (GP); grey, damp, ±¾-inchminus, angular, (base rock).Dense silty GRAVEL (GM); brown, low plasticity silt,damp, fine to coarse gravel, angular to subangulargravel, (fill).

Medium stiff to stiff SILT, some sand and gravel (ML);brown, low plasticity, damp, fine to coarse sand, finegravel, subangular gravel, (fill).

Medium stiff silty CLAY, trace sand and gravel,scattered organics (CL); grey and brown, mediumplasticity silt, moist, fine to coarse sand, fine gravel,subangular gravel, organics consist of wood debris,(fill).Loose silty SAND (SM); brown, low plasticity silt, wet,fine to coarse sand, (alluvium).

Trace gravel, some organics, and wet below ±15 feet.

Dense silty GRAVEL, some sand, scattered organics(GM); grey-brown, low plasticity silt, wet, fine to coarsesand, fine to coarse gravel, subangular to subroundedgravel, organics consist of wood debris, (alluvium).

Very dense silty ROCK FRAGMENTS (GM);grey-brown, low plasticity silt, wet, fine to coarsesand-sized and fine to coarse gravel-sized basalt rockfragments, angular, relict rock texture, (residual soil).

Very weak to weak (R1 to R2) BASALT; grey, slightlyweathered, (Basalt of Yachats).BOTTOM OF BORING

0.5

1.3

5.0

10.0

12.5

17.5

20.0

24.0

25.1

SS-1-1

SS-1-2

SS-1-3

SS-1-4

SS-1-5

SS-1-6

SS-1-7

SS-1-8

SS-1-9

Capped withAC cold

patch andgravel

Backfilledwith

bentonitechips


Moisture, %

RQD., %


Elev.

Depth Water Table0 50 100

Depth

Feet

Soil and Rock Descriptionand

CommentsLog

SPT,

0 50 100

Depth

Feet


CommentsLog

SPT,N-Value

DepthSamples

Installations/N-Value

Water Table

Moisture, %

RQD., %Recovery

Elev.Samples

Installations/

Recovery

Surface Elevation:

Boring Log: BH-1

September 9, 2016

Surface Elevation: Eckman Creek Culvert Replacement


1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

Date of Boring:

2161081Project No.:

Eckman Creek Culvert Replacement

Project No.:

Page 1 of 1Page 1 of 1


Boring Log: BH-1

September 9, 2016Date of Boring:

2161081

N/A

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

0.0

35

7

11

6

5

11

42

75

50/1st 1"

35

7

11

6

5

11

42

75

50/1st 1"

35

7

11

6

5

11

42

75

50/1st 1"

35

7

11

6

5

11

42

75

50/1st 1"

ASPHALTIC CONCRETE (±6 inches).Dense CRUSHED ROCK (GP); grey, damp, ±¾-inchminus, angular, (base rock).Dense silty GRAVEL, trace sand (GM); brown, lowplasticity silt, damp, fine to coarse sand, fine to coarsegravel, angular gravel, (fill).

Dense silty SAND, trace gravel (SM); brown, lowplasticity silt, moist, fine to coarse sand (?), finegravel, angular to subrounded gravel, (fill).

Medium dense silty SAND, trace gravel, scatteredorganics (SM); grey, low plasticity silt, wet, fine sand,fine gravel, subangular gravel, organics consist ofwood debris, (alluvium).

Soft clayey SILT, trace to some sand, scattered rockfragments (MH); grey and brown, medium plasticity,wet, fine to medium sand, coarse gravel-sizedsandstone rock fragments, (alluvium).

Loose silty SAND, some gravel, scattered organics(SM); grey-brown, low plasticity silt, wet, fine to coarsesand, fine to coarse gravel, subrounded to roundedgravel, organics consist of wood debris, (alluvium).

Medium dense GRAVEL, some sand, trace silt (GP);grey, wet, fine to coarse sand, fine to coarse gravel,subrounded gravel, (alluvium).

Very dense GRAVEL, some silt and sand, scatteredcobbles (GP); grey-brown, low plasticity silt, wet, fineto coarse sand, fine to coarse gravel, subrounded torounded gravel, cobbles up to ±6 inches in diameter,(alluvium).

Medium dense silty SAND, trace gravel (SM); grey,low plasticity silt, wet, fine to coarse sand, fine gravel,subrounded gravel, (alluvium).

BOTTOM OF BORING

0.5

1.3

5.0

10.0

12.5

15.0

17.5

20.0

28.0

31.5

SS-2-1

SS-2-2

SS-2-3

SS-2-4

SS-2-5

SS-2-6

SS-2-7

SS-2-8

SS-2-9

SS-2-10

Capped withAC cold

patch andgravel

Backfilledwith

bentonitechips


Moisture, %

RQD., %


Elev.

Depth Water Table0 50 100

Depth

Feet


CommentsLog

SPT,

0 50 100

Depth

Feet


CommentsLog

SPT,N-Value

DepthSamples

Installations/N-Value

Water Table

Moisture, %

RQD., %Recovery

Elev.Samples

Installations/

Recovery

Surface Elevation:

Boring Log: BH-2

September 9, 2016

Surface Elevation: Eckman Creek Culvert Replacement


1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

Date of Boring:

2161081Project No.:


Project No.:

Page 1 of 1Page 1 of 1


Boring Log: BH-2

September 9, 2016Date of Boring:

2161081

N/A

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

0.0

31

36

47

16

3

8

27

50/1st 5"

56

21

31

36

47

16

3

8

27

50/1st 5"

56

21

31

36

47

16

3

8

27

50/1st 5"

56

21

31

36

47

16

3

8

27

50/1st 5"

56

21

Appendix C Laboratory Test Results

ProfessionalGeotechnicalServices



Eckman Creek Culvert

Project 2161081

Table 1C. Natural Water Contents and Percent Fines

Sample

Number

Sample

Depth (ft)

Natural Water

Content

(percent)

Percent

Fines

SS-1-1 2.5 – 4.0 19.0

SS-1-2 5.0 – 6.5 28.2

SS-1-3 7.5 – 9.0 24.6

SS-1-4 10.0 – 11.5 47.5

SS-1-5 12.5 – 14.0 34.3 26.2

SS-1-6 15.0 – 16.5 40.1

SS-1-7 17.5 – 19.0 14.9

SS-1-8 20.0 – 21.5 19.1

SS-1-9 25.0 – 25.5 11.5

SS-2-1 2.5 – 4.0 21.7

SS-2-2 5.0 – 6.5 24.4

SS-2-3 7.5 – 9.0 19.6

SS-2-4 10.0 – 11.5 38.4 39.8

SS-2-5 12.5 – 14.0 53.5

SS-2-6 15.0 – 16.5 45.4 24.9

SS-2-7 17.5 – 19.0 14.2

SS-2-8 20.0 – 20.4 11.5

SS-2-9 25.0 – 26.5 15.5

SS-2-10 30.0 – 31.5 29.4



Project 2161081

Table 2C. Summary of Resistivity Testing

Location Pin Spacing

(ft.)

Resistivity

(-cm)

West of BH-2

6 21,831

9 16,890

12 12,064

Table 3C. pH Test Results (ASTM G51)

Sample

Number

Sample

Depth (ft) Sample Description pH

SS-1-4 10.0 – 11.5 Stiff, silty CLAY with

scattered organics (CL) 5.9

SS-2-5 12.5 – 14.0 Soft, clayey SILT with

scattered rock fragments (MH) 5.8

Documents

Foundation Engineering, Inc. · 9/29/2016 · meter (ASTM G57). The resistivity test was located west of BH-2. The approximate location is identified as R-1 on Figure 2A. The 4-pin