B08_Solit_SCBL_152851_Attach_08_Geotech_Report.pdf

Final

Geotechnical Investigation Report

Scotts Bluff National Monument

190276 Old Oregon Trail Road

Gering, Nebraska 69341

Yeh Project No.: 216-362

January 6, 2017

Prepared for:

Anderson Hallas Architects 715 Fourteenth Street

Golden, Colorado 80401 Attn: Ms. Nan Anderson

Prepared by:

Yeh and Associates, Inc.

2000 Clay Street, Suite 200

Denver, Colorado 80211

Phone: 303-781-9590 Fax: 303-781-9583 i

Table of Contents

1. PURPOSE AND SCOPE OF STUDY

2. PROPOSED CONSTRUCTION

3. GEOLOGICAL SETTING AND SITE CONDITIONS

4. SUBSURFACE INVESTIGATION

4.1 FIELD EXPLORATION

4.2 LABORATORY TESTING

5. SUBSURFACE CONDITIONS AND SEISMICITY

5.1 GROUNDWATER CONDITIONS

5.2 SEISMICITY

6. FOUNDATION DESIGN RECOMMENDATIONS

6.1 SPREAD FOOTINGS

6.2 EXTERIOR SLABS

6.3 LATERAL EARTH PRESSURES

6.4 FLOOR SLAB DESIGN AND CONSTRUCTION

6.5 DRAINAGE

7. CONSTRUCTION RECOMMENDATIONS

7.1 SITE GRADING CONSIDERATIONS

7.2 SUBGRADE PREPARATION

7.3 FILL MATERIALS AND PLACEMENT

7.4 EXCAVATION AND TRENCH CONSTRUCTION

7.5 DRAINAGE CONSIDERATIONS

8. OTHER DESIGN CONSIDERATIONS

8.1 WATER-SOLUBLE SULFATES

8.2 CORROSION POTENTIAL

9. LIMITATIONS

Figures

FIGURE 1 ─ BORING LOCATION PLAN SHEET

List of Appendices

APPENDIX A BORING LOGS AND LEGEND

APPENDIX B LABORATORY TEST RESULTS

APPENDIX C SITE PHOTOGRAPHS

Final Geotechnical Report Project No. 216-362 Scotts Bluff National Monument January 06, 2017

1. PURPOSE AND SCOPE OF STUDY

This report presents the results of our geotechnical engineering investigation. Yeh and

Associates, Inc. (Yeh) prepared this report to present the results from the site investigation for the proposed addition to the Scotts Bluff National Monument Visitor Center, located at Scotts

Bluff National Monument, Gering, Nebraska.

The study was performed in accordance with our proposal to Ms. Nan Anderson dated August

11, 2016 and your notice to proceed.

The existing building was constructed in the 1930s with 2 subsequent additions in the late

1930s and mid-1940s. Most of the existing building has a full-depth basement. The mid-1940s east wing addition has a slab on grade first floor. There is also a detached adobe restroom building (built in the mid-1930s on a concrete foundation). All of the existing foundations consist of concrete stems or basement walls over strip footings that vary in width from 1’-5” to 1’-9” at the widest. The mid-1940s addition has settled slightly relative to the original building.

2. PROPOSED CONSTRUCTION

The new addition will be single story, 2,532 square-foot, wood-framed building with a slab-on-grade floor (like the existing building). An exterior concrete stair on grade will be constructed under the new addition (a tunnel essentially) accessing the existing basement. The footings for the tunnel will be at the existing basement elevation which is roughly 10 feet below exterior grade.

3. GEOLOGICAL SETTING AND SITE CONDITIONS

The Scotts Bluff National Monument Visitor Center is located in a geologically unique setting.

Outcropping units of the Arikaree Group surround the center. Units of the Brule Formation as well as quaternary deposits underlie the center. The Arikaree Group is primarily identified by staggering cliffs above the North Platte River. The group is split into three major units; however, the group overall is predominantly volcaniclastic sediments of eolian or fluvial origin. Outcrops of sandy Siltstone, silty Sandstone, and Claystone of yellowish-grey to pale yellowish-brown are common.

Scotts Bluff National Monument January 06, 2017

Bedrock underlying the visitor center includes there members of the Brule Formation. The members vary between mudstone, siltstone, and sandstone and are composed of either eolian or fluvial volcaniclastic sediments. Coloring varies from greyish-brown to yellowish-orange.

Quaternary Deposits immediately underlie the center. These deposits consist of silt, sand, and minor gravel. The coloring can vary between brown and yellowish-grey. Although principally occurring on valley slopes, thicknesses can range between 10 and 80 feet thick.

4. SUBSURFACE INVESTIGATION

4.1 Field Exploration

The scope of the services performed for this project included site reconnaissance by a representative of Yeh and Associates, a subsurface exploration, laboratory testing and engineering analysis.

Yeh observed drilling for 2 borings (labeled YA-B1 and YA-2) on November 16, 2016. The approximate boring locations are shown on the Boring Log Site Plan, Figure 1. The borings logs are in Appendix A. Photographs of the site and boring locations are included in Appendix

C.

The recorded penetration resistance measurements were obtained by driving a California (CA) sampler typically at 5-foot intervals. The CA sampler is 24 inches in length, has an interior diameter of 2.0 inches, an outside diameter of 2.5 inches, and uses 4-inch long brass liners to collect samples. The sampler was seated at the bottom of the test hole, and then advanced by a

140 pound automatic hydraulic or “auto” hammer falling a distance of 30 inches. The driving procedure is similar to ASTM D3550, “Standard Practice for Thick Wall, Ring Lined, Split Barrel, Drive Sampling of Soils”. The sum of blows recorded was registered as the “Penetration

Resistance” of the soil encountered in the boring. The penetration resistance value (blow counts) is a useful index to the consistency and relative density or hardness of the materials encountered.

The borings were located in the field by measuring from existing features. The accuracy of boring locations should only be assumed to the level implied by the method used.

Scotts Bluff National Monument January 06, 2017

4.2 Laboratory Testing

Samples retrieved during the field exploration were tested by Yeh and Associates (Colorado

Analytical did the corrosion testing) and were classified in accordance with the AASHTO and

Unified Soil Classification Systems. An applicable program of laboratory testing was developed to determine engineering properties of the subsurface materials. Following the completion of the laboratory testing, the field descriptions were confirmed or modified as necessary and the boring logs were prepared.

Selected soil samples were tested for the following engineering properties:

Description and Identification of Soils (Visual-Manual Procedure)

Moisture Determination

Unit Weight

Grain Size Analysis

Atterberg Limits

Water Soluble Sulfates pH

One Dimensional Swell-Consolidation

The boring logs and laboratory test results were used for the geotechnical engineering analyses and the development of foundation and earthwork recommendations. Laboratory tests were performed in general accordance with the applicable local or other accepted standards.

Details of laboratory test results are presented in Appendix C, with a summary integrated with the boring logs in Appendix C.

5. SUBSURFACE CONDITIONS AND SEISMICITY

The borings indicate that the subsurface profile consists of a thin layer of topsoil overlying silty sand to 8 feet in YA-B1 and 9 feet in YA-B2. Below the silty sand, interlayered clay and silt of variable thickness was encountered to the full depth of exploration. Bedrock was not encountered on the site within the maximum depth of exploration. Field penetration data indicates that the clay soils vary from medium stiff to hard in consistency and the sand soils are medium dense in relative density. The soil samples tested were classified as CL and SC according to the USCS classification system and had indicated fines contents that varied from

46% to 81% and plasticity indexes from 16 to 23.

Scotts Bluff National Monument January 06, 2017

5.1 Groundwater Conditions

Wet soil lenses were observed, however groundwater did not develop in the test borings at the time of field exploration, nor when checked immediately after drilling. These observations represent only current groundwater conditions at the time of field exploration, and may not be indicative of other times, or at other locations. Groundwater levels should be expected to fluctuate with varying seasonal, irrigation, and weather conditions.

5.2 Seismicity

Based upon the nature of the subsurface materials, a Site Class D should be used for the design of the structure for the proposed project (ASCE 7-10 Standard, Site coordinates 41.8286

N, 103.7073 W). The project site is located in seismic area with a mapped maximum short period (SS) and 1-second period (S1) ground motion, respectively, of 0.114 g and 0.0.045 g as indicated on Figures 22-1 and 22-2. The site coefficients, Fa and Fv, for the same periods are

1.6 and 2.4, respectively.

6. FOUNDATION DESIGN RECOMMENDATIONS

The site appears suitable for the proposed construction based upon geotechnical conditions encountered in the borings. Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, we recommend that the proposed building structure be supported on a spread footing foundation system bearing on native soils or engineered fill.

Design and construction details for the foundation options are given for Allowable Stress Design

(ASD).

6.1 Spread Footings

As previously stated, spread footing foundation bearing upon undisturbed soils and/or engineered fill is recommended for support of the proposed structure. The building footings may be designed for a maximum allowable bearing pressure of 2,000 pounds per square foot

(psf). The design bearing pressure applies to dead loads plus design live load conditions. The design bearing pressure may be increased by 1/3 or as allowed by local code when considering total loads that include wind or seismic conditions. Recommended minimum widths of column and wall footings are 24 inches and 18 inches, respectively.

Exterior footings should be placed a minimum of 3 feet below finished grade for frost protection and to provide confinement for the bearing soils. Interior footings should bear a minimum of 12

Scotts Bluff National Monument January 06, 2017 inches below finished grade. Finished grade is the lowest adjacent grade for perimeter footings and floor level for interior footings.

Footings should be proportioned to reduce differential foundation movement. Proportioning on the basis of equal total movement is recommended; however, proportioning to relative constant dead load pressure will also reduce differential movement between adjacent footings. Total movement is estimated to be on the order of 1 inch or less. Differential movement should be on the order of ½ to ¾ of the estimated total movement. Additional foundation movements could occur if water from any source infiltrates the foundation soils, therefore, proper drainage should be provided in the final design and during construction.

Areas of loose soils may be encountered at foundation bearing depth. When such conditions exist beneath planned footing areas, the subgrade soils should be compacted prior to placement of the foundation system. If unsuitable materials or construction debris are encountered in the footing excavations, they should be removed and replaced with engineered fill, placed and compacted as discussed in the Earthwork section.

Footings, foundations and masonry walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities and at periodic intervals on long masonry walls is recommended.

Foundation excavations should be observed by the geotechnical engineer. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required.

6.2 Exterior Slabs

Some of the on-site soils, whether in-place or used in fills, have susceptibility to frost heave.

There is the potential for frost to develop in the soils adjacent to the building during the winter season. Covering of the native soils and/or introduction of moisture from irrigation or concentrated precipitation may increase the moisture content of the soils and result in frost heave. Therefore, movement may occur in exterior concrete slabs, which can result in off-sets, tilting and cracking. The movement and cracking may affect the appearance and performance of the slabs and can affect the slab’s compliance with ADA requirements. There are several mitigation measures to improve the slab’s appearance and performance; however, these options are not solely related to the geotechnical aspects so input from the design team is

Scotts Bluff National Monument January 06, 2017 suggested. In areas where movement is to be mitigated we believe these options can be considered.

The upper 24 inches of the native subgrade soils could be removed and replaced with imported granular non-plastic fill with less than 10 percent fines content.

At entrances to the building, the exterior slab may be structurally tied to the building foundation. This detail would reduce offsets between the exterior slab and the building interior; however, the movement may be translated to other portions of the exterior slab.

The structural engineer should also include uplift loads from the exterior slab in designing the foundation.

Moisture is one of the key elements; therefore, elimination of irrigation around the exterior slabs, directing roof discharges away from these slabs and preventing snow accumulation adjacent to the slabs can reduce the potential for movement.

Use of plants that do not require irrigation and will help absorb the moisture beneath the exterior slab without creating large root masses, which could cause slab movement, may also reduce potential movement.

Yeh and Associates is available to discuss other options and the potential risk of exterior slab movement if requested.

6.3 Lateral Earth Pressures

Cohesionless soils are recommended for backfilling foundation units. For the on-site cohesionless soils above any free water surface, recommended equivalent fluid pressures for unrestrained foundation elements are:

Active:

Cohesionless soil backfill (on-site sand) ...................................................... 38 psf/ft

Compacted granular backfill ....................................................................... 35 psf/ft

Passive:

Cohesionless soil backfill (on-site sand) .................................................... 327 psf/ft

Coefficient of base friction ................................................................................................ 0.45

Where the design includes restrained elements, the following equivalent fluid pressures are recommended:

At rest:

Cohesionless soil backfill (on-site sand) ...................................................... 57 psf/ft

Compacted granular backfill ........................................................................ 54 psf/ft

Scotts Bluff National Monument January 06, 2017

The lateral earth pressures herein do not include any factor of safety and are not applicable for submerged soils/hydrostatic loading. Additional recommendations may be necessary if submerged conditions are to be included in the design.

Compaction of each lift adjacent to walls should be accomplished with hand-operated tampers or other lightweight compactors. Over compaction may cause excessive lateral earth pressures, which could result in wall movement.

Foundations should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement.

6.4 Floor Slab Design and Construction

Non-expansive or engineered fill will support the floor slab. Some differential movement of a slab-on-grade floor system is possible should the subgrade soils become elevated in moisture content. To reduce potential slab movements, the subgrade soils should be prepared as outlined in section 7.2 of this report.

For structural design of concrete slabs-on-grade, a modulus of subgrade reaction of 100 pounds per cubic inch (pci) may be used for floors supported on existing or engineered fill consisting of on-site soils. A modulus of 200 pci may be used for floors supported on 12 inches of non-expansive, imported fill meeting the specifications of section 7.3.

Additional floor slab design and construction recommendations are as follows:

Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement.

Control joints should be provided in slabs to control the location and extent of cracking.

Interior trench backfill placed beneath slabs should be compacted in accordance with recommended specifications outlined herein.

In areas subjected to normal loading, a minimum 4-inch layer of sand, clean graded gravel or aggregate base course should be placed beneath interior slabs. For heavy loading, reevaluation of slab and/or base course thickness may be required.

If moisture-sensitive floor coverings are used on interior slabs, consideration should be given to the use of barriers to minimize potential vapor rise through the slab.

Floor slabs should not be constructed on frozen subgrade.

Scotts Bluff National Monument January 06, 2017

Other design and construction considerations, as outlined in Section 302.1 R of the "ACI

Design Manual", are recommended.

6.5 Drainage

It is our understanding that the existing building’s basement has experienced ground water seepage as well as standing water in the past.

Perched groundwater occurs when the subsurface soils consisting of relatively higher permeable soils overlay less permeable soils. Considering this site has 8 to 9 feet of cohesionless soils (silty sands) overlying clays, a perched water table developing during high moisture years probably caused the wet basement. This condition may continue to occur in the future. Site development completion, including installation of landscaping and irrigation systems, may lead to additional perched groundwater development.

To reduce the potential for perched groundwater impacting the additions foundation bearing soils, installation of a perimeter drainage system is recommended. The drainage system should be constructed around the exterior perimeter of the foundation and sloped at a minimum ½ percent to a suitable outlet, such as a sump and pump system. The recommended perforated pipe size is 6 inches.

The drainage system should consist of a properly sized, perforated pipe that is embedded in free-draining gravel and placed in a trench at least 12 inches in width. Gravel should extend beneath the bottom of the pipe and at least 12 inches above the bottom of the foundation wall.

The system should be underlain with a polyethylene moisture barrier that is sealed to the foundation walls and extends to at least the edge of the backfill zone. The gravel should be covered with drainage fabric prior to placement of foundation backfill.

7. CONSTRUCTION RECOMMENDATIONS

The following presents recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills on the project.

Earthwork on the project should be observed and evaluated by Yeh and Associates. The evaluation of earthwork should include observation and testing of engineered fills, subgrade preparation, foundation bearing soils and other geotechnical conditions exposed during the construction of the project.

Scotts Bluff National Monument January 06, 2017

7.1 Site Grading Considerations

Strip and remove existing vegetation and other deleterious materials from proposed building and pavement areas. All exposed surfaces should be free of mounds and depressions, which could prevent uniform compaction.

Stripped materials consisting of vegetation and organic materials should be wasted from the site or used to revegetate landscaped areas after completion of grading operations.

All exposed areas which will receive fill, once properly cleared, should be scarified to a minimum depth of 12 inches, conditioned to near optimum moisture content, and compacted.

Underground facilities such as septic tanks and utilities could be encountered during construction. If unexpected fills or underground facilities are encountered, such features should be removed and the excavation extended to native materials prior to backfill placement and/or construction.

Based upon the subsurface conditions encountered, subgrade soils exposed during construction are anticipated to be relatively stable. However, the stability of the subgrade may be affected by precipitation, repetitive construction traffic and other factors. If unstable conditions are encountered or develop during construction, stability may be improved by scarifying and drying the subgrade soils. Over excavation of wet zones and replacement with granular materials or crushed rock may be necessary. Use of fly ash, kiln dust, cement or geotextiles could also be considered as stabilization techniques. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction.

7.2 Subgrade Preparation

Subgrade soils beneath interior and exterior slabs should be scarified; moisture conditioned and compacted to a minimum depth of 12 inches. The moisture content and compaction of subgrade soils should be maintained until slab construction.

7.3 Fill Materials and Placement

Clean on-site soils or approved imported materials may be used as fill material. Imported soils

(if required) should be granular soils with no more than 35 percent passing the No. 200 sieve and a Plastic Limit of less than 15. Import fill material should be reviewed by the geotechnical engineer prior to importing to the site.

Scotts Bluff National Monument January 06, 2017

Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce a uniform fill with the recommended moisture contents and densities throughout the lift. Recommended compaction criteria for engineered fill is 95 percent of the maximum dry density as determined by ASTM D698, at a moisture content within 2 percent of optimum for granular soils and 0 to 2 percent above optimum for clay soils.

7.4 Excavation and Trench Construction

Excavations into the on-site soils will encounter a variety of conditions. All excavations must comply with the applicable local, State, and Federal safety regulations, and particularly with the excavation standards of the Occupational Safety and Health Administration (OSHA).

Construction site safety, including excavation safety, is the sole responsibility of the Contractor as part of its overall responsibility for the means, methods, and sequencing of construction operations. Yeh and Associates recommendations for excavation support is provided for the

Client’s sole use in planning the project, in no way do they relieve the Contractor of its responsibility to construct, support, and maintain safe slopes. Under no circumstances should the following recommendations be interpreted to mean that Yeh and Associates is assuming responsibility for either construction site safety or the Contractor’s activities.

We believe the overburden soil encountered on this site will classify as a Type C material, using

OSHA criteria. OSHA requires that unsupported cuts be no steeper than 1½:1 for Type C for unbraced excavations up to 20 feet in height. In general, we believe that these slope ratios will be temporarily stable under unsaturated conditions. Flattened slopes may be required if excavations encounter groundwater or the slopes will be exposed for an extended period of time. Please note that an OSHA-qualified “competent person” must make the actual determination of soil type and allowable sloping in the field.

The soils encountered by the proposed excavations may vary significantly across the site. The preliminary classifications presented above are based solely on the materials encountered in widely spaced exploratory test borings. The contractor should verify that similar conditions exist throughout the proposed area of excavation.

As a safety measure, it is recommended that all vehicles and soil piles be kept to a lateral distance equal to at least the depth of the excavation from the crest of the slope. The exposed slope face should be protected against the elements and monitored by the contractor on at least a daily basis.

Scotts Bluff National Monument January 06, 2017

7.5 Drainage Considerations

Positive drainage should be provided during construction and maintained throughout the life of the proposed project. Proper design of drainage should include prevention of ponding of water on or immediately adjacent to the structures. Surface features that could retain water in areas adjacent to the structures should be sealed or eliminated. In areas where paving does not immediately adjoin the structure, we recommend that, if feasible, protective slopes be provided with a minimum grade of approximately 5 percent for at least 5 feet. Backfill against any kind of structure and in utility line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration and migration. Concentrated runoff should be avoided in areas susceptible to erosion and slope instability. Slopes and other stripped areas should be protected against erosion by re-vegetation or other method.

8. OTHER DESIGN CONSIDERATIONS

8.1 Water-Soluble Sulfates

The concentration of water-soluble sulfates measured in a sample obtained from the borings was 0.010 percent. This concentration of water-soluble sulfates represents a Class 0 degree of sulfate attack on concrete exposed to these geologic materials. The degree of attack is based on a range of Class 0 (negligible) to Class 3 (very severe) as described in the American

Concrete Institute (ACI) Standard 201.2R, “Guide to Durable Concrete” and a Class 0 as presented in the CDOT Section 601, Structural Concrete, of the Standard Specifications for

Road and Bridge Construction, 2011 edition.

Based on this sulfate test results, the soils present a negligible potential for sulfate attack on concrete. Results of soluble sulfate testing indicate that ASTM Type I, Portland cement should be specified for all project concrete on and below grade. However, if there is no (or minimal) cost differential, use of ASTM Type II Portland cement is recommended for additional sulfate resistance of construction concrete.

8.2 Corrosion Potential

The pH was determined for a selected sample. Test results measured pH value of 8.3

(considered slightly basic). A qualified corrosion engineer should review this data to determine the appropriate level of corrosion protection

Scotts Bluff National Monument January 06, 2017

9. LIMITATIONS

The analyses and recommendations presented in this report are based upon our data obtained from the borings at the indicated locations, field observations, laboratory testing, our understanding of the proposed construction and other information discussed in this report. It is possible that subsurface conditions may vary between or beyond the points explored. The nature and extent of such variations may not become evident until construction. If variations in conditions from those described in this report appear, we should be contacted immediately so we can review our report in light of the variations and provide supplemental recommendations as necessary. Before any deviation from recommendations given in the report is taken we should be notified. We should also review the report if the scope of the proposed construction, including the proposed loads, finished elevations or structure design, change from those as described in this report. The conclusions and recommendations contained in this report shall not be considered valid unless Yeh and Associates reviews the changes and either verifies or modifies the conclusions of this report in writing.

We have prepared this report for the exclusive use of Anderson Hallas Architects for the proposed improvements of the Scotts Bluff National Monument Visitors Center Building in

Gering, Nebraska. The report was prepared in substantial accordance with the generally accepted standards of practice for geotechnical engineering as exist in the site areas at the time of our investigation. No warranties, express or implied, are intended or made. The recommendations in this report are based on the assumption that Yeh and Associates will conduct an adequate program of construction testing and observation to evaluate compliance with our recommendations.

Figure 1 ─ Boring Location Plan Sheet

Appendix A

BORING LOGS AND LEGEND

Project Number: 216-362

Scotts Bluff NM

Legend for Symbols Used on Borehole Logs

Yeh and Associates, Inc.

C o n s u l t i n g E n g i n e e r s & S c i e n t i s t s

Sample Types

Auger Cuttings

Modified California Sampler (2.5 inch OD, 2.0 inch ID)

Lithology Symbols

Project:

(see Boring Logs for complete descriptions)

USCS Low Plasticity Clay USCS Silt USCS Silty Sand Topsoil

1. "Penetration Resistance" on the Boring Logs refers to the N value for SPT samples only, as per ASTM D1586. For samples obtained with a Modified California sampler, drive depth was 12 inches, and "Penetration Resistance" refers to the sum of all blows. For all sample types, where blow counts were more than 50 for the last increment, the blows and length for the last increment are reported under "Penetration Resistance."

2. The Modified California sampler used to obtain samples is a 2.5-inch OD, 2.0-inch ID (1.95-inch ID with liners), split-barrel sampler with internal liners, as per ASTM D3550. Sampler is driven with a 140-pound hammer, dropped 30 inches per blow.

Lab Test Standards Other Lab Test Abbreviations pH Soil pH (AASHTO T289-91) S Water-Soluble Sulfate Content (AASHTO T290-91, ASTM D4327)

Chl Water-Soluble Chloride Content (AASHTO T291-91, ASTM D4327)

S/C Swell/Consolidation (ASTM D4546) UCCS Unconfined Compressive Strength (ASTM D2166) R-Value Resistance R-Value (ASTM D2844) DS (C) Direct Shear cohesion (ASTM D3080) DS (phi) Direct Shear friction angle (ASTM D3080) Re Electrical Resistivity (AASHTO T288-91) PtL Point Load Strength Index (ASTM D5731)

Notes

Moisture Content ASTM D2216 Dry Density ASTM D7263 Sand/Fines Content ASTM D421, ASTM C136, ASTM D1140

Atterberg Limits ASTM D4318 AASHTO Class. AASHTO M145, ASTM D3282

USCS Class. ASTM D2487 (Fines = % Passing #200 Sieve Sand = % Passing #4 Sieve, but not passing #200 Sieve)

A-6 (4)

SC46 1638

pH=8.3 S=0.01%

UCCS=2194psf

27.0

30.9

32.7

84.0

85.9

81.3

5-9

6-7

7-8

50:6"-50:2"

37-50:3"

37-50:4"

50:2"

50:3"

50:4"

0.0 - 0.2 ft. 2" TOPSOIL.

0.2 - 8.0 ft. silty SAND, brown, moist, medium dense.

8.0 - 14.0 ft. CLAY and SILT, slightly sandy, brown, moist, stiff.

14.0 - 26.3 ft. CLAY with variable amounts of silt, brown, interlayered moist and stiff to dry and hard.

Bottom of Hole at 26.3 ft.

Total Depth: 26.3 ft

Ground Elevation:

Coordinates: N: E:

Location:

Groundwater Levels:

Logged By: S. Sherwood

Final By: M. Boyd

Symbol Depth Date

Weather Notes: Clear, 50F

Inclination from Horiz.: Vertical

Boring Began: 11/16/2016

Boring Completed: 11/16/2016

Drilling Method(s): Hollow-Stem Auger

Driller: Panhandle Geotechnical

Drill Rig:

Hammer Type:

Night Work:

Project Name:

PAGE

AASHTO

& USCS

Classifi-cations

F in es C on te nt

P la st ic ity In de x

Project Number: 216-362

Scotts Bluff NM

Atterberg Limits

Boring No.: YA-B1 Yeh and Associates, Inc.

E le va tio n (f ee t)

D ep th (f ee t)

S am pl e

T yp e/ A dv an ce m en t M et ho d

C o n s u l t i n g E n g i n e e r s & S c i e n t i s t s

Li qu id Li m it

Field Notes and

Other Lab Tests

B O

R

IN

G L

O G

-3

2.

G P

J

Y E

H A

S S

O C

IA

T

E S

T E

M P

LA

T

E .G

D T

L

IB

R

A R

Y .G

LB

2/

5/

S an d C on te nt

G ra ve l C on te nt

M oi st ur e C on te nt

D ry

D en si ty

(p cf

)Blows per 6 in

P en et ra tio n

R es is ta nc e

Li th ol o gy

Material Description

Soil Samples

A-7-6 (19)

CL

81 2346

S/C=-0.3%

18.6

27.8

28.0

28.1

88.5

86.2

86.3

85.4

5-7

8-7

2-5

9-50:5"

14-50:4"

25-50:6"

50:5"

50:4"

50:6"

0.0 - 0.2 ft. 2" TOPSOIL.

0.2 - 9.0 ft. silty SAND, brown, moist, medium dense.

9.0 - 12.0 ft. sandy SILT, brown, moist, medium stiff.

12.0 - 18.0 ft. CLAY with some sand, brown, moist to wet, hard.

18.0 - 26.5 ft. CLAY, brown, interlayered moist/wet and stiff to dry and hard.

Bottom of Hole at 26.5 ft.

Total Depth: 26.5 ft

Ground Elevation:

Coordinates: N: E:

Location:

Groundwater Levels:

Logged By: S. Sherwood

Final By: M. Boyd

Symbol Depth Date

Weather Notes: Clear, 60F

Inclination from Horiz.: Vertical

Boring Began: 11/16/2016

Boring Completed: 11/16/2016

Drilling Method(s): Hollow-Stem Auger

Driller: Panhandle Geotechnical

Drill Rig:

Hammer Type:

Night Work:

Project Name:

PAGE

AASHTO

& USCS

Classifi-cations

F in es C on te nt

P la st ic ity In de x

Project Number: 216-362

Scotts Bluff NM

Atterberg Limits

Boring No.: YA-B2 Yeh and Associates, Inc.

E le va tio n (f ee t)

D ep th (f ee t)

S am pl e

T yp e/ A dv an ce m en t M et ho d

C o n s u l t i n g E n g i n e e r s & S c i e n t i s t s

Li qu id Li m it

Field Notes and

Other Lab Tests

B O

R

IN

G L

O G

-3

2.

G P

J

Y E

H A

S S

O C

IA

T

E S

T E

M P

LA

T

E .G

D T

L

IB

R

A R

Y .G

LB

2/

5/

S an d C on te nt

G ra ve l C on te nt

M oi st ur e C on te nt

D ry

D en si ty

(p cf

)Blows per 6 in

P en et ra tio n

R es is ta nc e

Li th ol o gy

Material Description

Soil Samples

Appendix B

LABORATORY TEST RESULTS

Rev 2 - 8/02 Page 1 of 1

Project No: Date: 12/1/2016

Gradation Atterberg

YA-B1 0-5 Bulk

8.3 0.010

YA-B1 5 CA 27.0 84.0

YA-B1 10 CA 30.9 85.9 0 54 46 38 22 16

A-6 ( 4 ) SC

YA-B1 15 CA 32.7 81.3

YA-B1 20 CA 36.4 80.8

YA-B2 2.5 CA 18.6 88.5

YA-B2 5 CA 27.8 86.2

-0.3

YA-B2 10 CA 28.0 86.3

YA-B2 15 CA 28.1 85.4 0 19 81 46 23 23

A-7-6 ( 19 ) CL

Water Soluble Sulfate

Unconfined Comp-

Strength (psf)

PL PI AASHTO USCS

CLASSIFICATIONSwell [+] / Consolidation [-]

Gravel > #4

Sand

Fines < #200

LLBoring No.

PH

YEH & ASSOCIATES, INC

Summary of Laboratory Test Results

216-362 Project Name: Scott Bluff N.M

Sample Location Natural Moisture Content

Natural Dry

Density (pcf)

Depth (ft) Sample Type

Revised 04/27/2004

Drawn By: MA

Date: 12/01/16

Sieve Size

Passing

Checked By: SCS

3"

2 ½"

2"

⅜"

#4

#10

#40

1 ½"

1"

Sample Description: A-7-6 (19) / CL

Project No.: 216-362

Figure No.: -

Fines (%) 81 PI 23

Scotts Bulff N.M Project Name:

Sample ID: B-2

Sample Depth (ft.): 15

Gravel (%)

Sand (%)

LL

PL

¾ "

½"

#200 81

Yeh & Associates, Inc.

Geotechnical Engineering Consultants

SIEVE ANALYSIS

0.010.11101001000

Pe rc en t P as si ng

Particle Size (mm)

200 40 10 3/8" 4 1/2" 3/4" 3" 12" 6" 1" 30 50 8 16

Sieve Analysis Hydrometer Analysis

Sieve Opening in Inches U.S. Standard Sieves Size of Particles in mm

100 2"

Applied Normal Pressure, ksf

Job No:

M.A

Boring Number Depth, ft

SCS

YEH & ASSOCIATES, INC

216-362 Project Name: Scott Bluff N.M Checked By:

B-2 86.2 27.8% -0.3 Drawn By:

Natural Dry

Density, pcf

Moisture Content, Consolidation(-) /Swell(+), % Soil Classification

SWELL /

CONSOLIDATION

GRAPH

-8.0

-6.0

-4.0

-2.0

0.0

2.0

4.0

6.0

8.0

0.1 1 10 100

C on so lid at io n(

/S w el l(+

WATER ADDED

Appendix C

SITE PHOTOGRAPHS

Drilling Boring YA-B1

Drilling Boring YA-B2

Boring YA-B1 upon Completion

Boring YA-B2 upon Completion