GEOTECHNICAL INVESTIGATION I-15 MILE POST CL 120

GEOTECHNICAL INVESTIGATION

I-15 MILE POST CL 120 INTERCHANGE

MESQUITE, NEVADA

PREPARED FOR:

HORROCKS ENGINEERS2162 WEST GROVE PARKWAY, SUITE 400

PLEASANT GROVE, UTAH 84062

ATTENTION: BRIAN ATKINSON, [email protected]

PROJECT NO. 2100948 MAY 19, 2011 (Revised June 22, 2011)

TABLE OF CONTENTS

EXECUTIVE SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1

SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 3

SITE CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 5

FIELD STUDY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 5

SUBSURFACE CONDITIONS AND LABORATORY TESTING . . . . . . . . . . . . . . . . . Page 5

SUBSURFACE WATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 10

PROPOSED CONSTRUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 11

RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12A. Site Grading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 12B. Permanent Shallow Foundations . . . . . . . . . . . . . . . . . . . . . . . . . Page 24C. Temporary Pile Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 27D. Concrete Slab-on-Grade/Curb . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 31E. Lateral Earth Pressures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 31F. Seismicity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 33G. Liquefaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 34H. Water Soluble Sulfates and Cement Type . . . . . . . . . . . . . . . . . . Page 35I. Corrosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 35J. Construction Testing and Observation . . . . . . . . . . . . . . . . . . . . . page 36

LIMITATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 37

FIGURES

Vicinity Map Figure 1Site Plan Figure 2Logs of Test Pits Figure 3Logs of Exploratory Borings Figures 4-9Legend and Notes of Test Pits and Exploratory Borings Figure 10Consolidation Test Results Figures 11-23Direct Shear Test Results Figures 24-29Gradation and Moisture-Density Relationship Results Figures 30-35Sieve Analysis Test Report Figures 36-45Factored Bearing Resistance vs Effective Footing Width Figure 46Driven H-Pile Capacities Figure 47Pile Head Deflection Figure 48Maximum Moment Figure 49Pile Deflection Figures 50-53

Summary of Laboratory Test Results Table 1Summary of Chemical Laboratory Test Results Table 2Subcontracted Laboratory Tests Appendix

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APPLIED GEOTECHNICAL ENGINEERING CONSULTANTS, INC. 2100948

EXECUTIVE SUMMARY

1. The subsurface soil profile observed in the test pits excavated and the borings drilledat the site generally consists of varying thicknesses of site grading fill overlying naturalpoorly graded sand with silt to silty sand. The fill thickness observed varies fromapproximately 1 foot to approximately 31 feet. Fill was not encountered in Test Pit TP-4 and Borings B-10 through B-13 on the eastern portion of the site. Poorly gradedgravel with sand was encountered near the surface in Borings B-11 through B-13. Fatclay was encountered near the bottom of B-13 at a depth of approximately 27 feet anda layer of lean clay was encountered in Test Pit TP-2 at a depth of approximately 10feet.

2. Subsurface water was not encountered in the borings and test pits by AGEC to themaximum depth investigation, approximately 70 feet with the exception of boring B-12. Groundwater was encountered at approximately 37 feet in Boring B-12 at the timeof the exploration. This corresponds to an elevation of approximately 1,558½ feet.Review of the “Baseline Geotechnical Investigation” indicates groundwater wasencountered at depths ranging from approximately 67 to 75 feet below the existinggrade. This corresponds to an elevation ranging from approximately 1,557½ feet to1,561 feet. Fluctuations in groundwater level may occur over time. We anticipate thegroundwater depth/elevation will likely remain relatively constant throughout the year.

3. The subject site is suitable to support the proposed construction providedrecommendations included within this report are followed.

4. Observations, penetration values (blow counts) and laboratory testing indicates the fillobserved is generally moderately to well compacted and consists of silty sand to poorlygraded sand with varied amounts of gravel mixed with some clay.

5. The proposed bridge overpass may be permanently supported on conventional spreadfootings bearing on a properly compacted subgrade as provided in the PermanentShallow Foundations section of the report. Factored bearing resistances are providedon Figure 46.

6. Observations and laboratory testing indicate the on-site fill soils and natural sand soils(including soils sampled by NDOT during preparation of the Baseline GeotechnicalInvestigation), are suitable for use as Borrow, Selected Borrow and Backfill inaccordance with Sections 203 and 207 of the State of Nevada DOT, “StandardSpecifications for Road and Bridge Construction”, 2001 and “Pull Sheets” from thecontract documents. Chemical tests conducted by NDOT and by AGEC should bereferred to if corrosion to buried structures is a concern.

7. Geotechnical information related to foundations, subgrade preparation, excavation,compaction and materials, retaining structures and seismic design criteria are includedwithin this report.

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8. Information presented in this summary should not be used independent of thatcontained within the body of the report.

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SCOPE

This report presents the results of a geotechnical investigation for the proposed I-15 Mile Post

CL120 Interchange in Mesquite, Nevada at the approximate location shown on Figure 1. This

report presents the subsurface conditions encountered, laboratory test results, and

recommendations for the geotechnical aspects of the project. Geotechnical aspects include

temporary and permanent bridge foundation support recommendations, material

suitability/grading recommendations, retaining design parameters and seismic characteristics

of the subsurface soils.

Field exploration was conducted to obtain information on the subsurface conditions. Samples

obtained from the field investigation were tested in the laboratory to determine physical and

engineering characteristics of the on-site soil. Information obtained from the field and

laboratory along with information contained in the Baseline Geotechnical Investigation was

used to define conditions at the site for our engineering analysis and to develop

recommendations for the proposed construction.

This report has been prepared to summarize the data obtained during the study and to present

our conclusions and recommendations based on the proposed construction and the subsurface

conditions encountered. Design parameters and a discussion of geotechnical engineering

considerations related to construction are included in the report.

The geotechnical design criteria and recommendations are based upon the following

supporting documents and information:

1. “Geotechnical Policies and Procedures Manual”, 2005, Nevada DOT.

2. “Baseline Geotechnical Report , I-15 Milepost CL120 Interchange, Design

Build”, July, 2010, prepared by Nevada DOT, Material Division.

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3. Subsurface investigation and laboratory testing completed by AGEC.

4. “AASHTO LRFD Bridge Design Specifications”, Fifth Edition, 2010.

5. “Guide Design Specification for Bridge Temporary Works”, published by

AASHTO, 1995.

6. “Standard Specifications for Road and Bridge Construction”, State of Nevada

DOT, 2001.

7. “West Mesquite Interchange Design-Build Project”, Part 9 - Contract Documents

Appendix A Pull Sheets, April 4, 2011.

8. Drawings and plans, prepared by Horrocks Engineers.

9. “Structures Manual”, Nevada DOT, September, 2008.

10. “Manual for Design & Construction Monitoring of Soil Nail Walls”, Publication

No. FHWA-SA-96-069R, October 1998.

11. “Geotechnical Circular No. 7", Report No. FHWA0-IF-03-017, prepared for

FHWA, March 2003.

12. “Foundation Analysis and Design”, Fourth Edition, Joseph E. Bowles.

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SITE CONDITIONS

The subject site is located in Mesquite, Clark County, Nevada at the I-15 mile post CL120

interchange as shown on Figure 1. There is currently an existing 3 span bridge super

structure. We understand the existing bridge is supported on conventional spread footings.

The existing bridge facilitates the travel of the north and south bound I-15 traffic over Falcon

Ridge Parkway. Falcon Ridge Parkway is aligned beneath the overpass extending east and

intersects Mesquite Blvd. There is cultivated, undeveloped property and residences to the east

and developed commercial portions of Mesquite to the east and west.

FIELD STUDY

On March 14, 15, 16 and 17, an engineer from AGEC visited the site and observed the

excavation of 5 test pits and the drilling of 13 borings at the approximate locations shown on

the site plan, Figure 2. The test pits were excavated using a rubber tired backhoe. Borings

were drilled utilizing a truck mounted drill rig equipped with 8-inch diameter hollow-stem

augers. The test pits and borings were logged and soil samples obtained by an engineer from

AGEC. Logs of the subsurface conditions encountered in the test pits and borings are shown

graphically on Figures 3-9 with the Legend and Notes of Test Pits and Borings shown on

Figure 10.

SUBSURFACE CONDITIONS AND LABORATORY TESTING

The subsurface soil profile observed in the test pits excavated and the borings drilled at the

site generally consists of varying thicknesses of site grading fill overlying natural poorly graded

sand with silt to silty sand. The fill thickness observed varies from approximately 1 foot to

approximately 31 feet. Fill was not encountered in Test Pit TP-4 and Borings B-10 through

B-13 on the eastern portion of the site. Poorly graded gravel with sand was encountered near

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the surface in Borings B-11 through B-13. Fat clay was encountered near the bottom of B-13

at a depth of approximately 27 feet and a layer of lean clay was encountered in Test Pit TP-2

at a depth of approximately 10 feet. Asphaltic concrete pavement overlying base course was

encountered at the surface in Boring B-6.

Descriptions of the subsurface soils and encountered in the test pits and borings follows:

Asphalt - Moderate condition and black in color.

Base Course - Appears well compacted, moist and brown in color.

Cultivated soil - The cultivated soil consists of silty to clayey sand. It is loose to

medium dense, moist, contains roots and is brown in color.

Fill - (USC Soil Classification: SM to SC, AASHTO Soil Classification: A-2-4) - The fill

consists of silty sand to poorly graded sand mixed with varied amounts of gravel and

clay. It generally appears moderately to well compacted, moist, non to low plastic and

light brown in color.

Laboratory tests conducted on samples of the fill indicate in-place moisture contents

ranging from 3 to 12 percent, in-place dry densities ranging from 103 to 113 pounds

per cubic foot (pcf), gravel contents (percent retained on the No. 4 sieve) ranging from

0 to 28 percent and fines contents (percent passing the No. 200 sieve) ranging from

9 to 25 percent. Atterberg Limits tests conducted on samples of the fill indicate the

material tests is non-plastic. Moisture-density Relationship (modified proctor) tests

conducted on samples of the fill indicate maximum dry densities ranging from 122.5

to 134.5 pcf with optimum moisture contents ranging from 6.5 to 11.0 percent. R-

value tests conducted on samples of the fill indicate R-values ranging from 64 to 75

at 300 psi exudation pressure.

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Direct shear tests conducted on samples of the fill remolded at approximately 95

percent of the maximum dry density and near the optimum moisture content indicate

peak friction angles ranging from 40 to 42 degrees and peak cohesion values ranging

from 340 to 550 pounds per square foot (psf). A direct shear test conducted on a

sample of the fill in its existing condition indicates a peak friction angle of 32 degrees

and peak cohesion value 780 psf.

Several water soluble sulfate tests conducted on samples of the fill indicate water

soluble sulfate concentrations ranging from 300 to 1,200 parts per million (ppm).

Laboratory resistivity tests conducted on the fill indicate resistivities ranging from 450

to 1,400 ohm-cm. Chloride concentrations ranging from 11 to 161 ppm and pH values

ranging from 8.1 to 9.0 were also measured on samples of the fill.

A one-dimensional consolidation test conducted on a sample of the fill indicates it is

slightly moisture sensitive (collapsible) when wetted under a constant pressure of

approximately 1,000 psf and slightly compressible under additional loading. We

anticipate a portion of the measured collapse in the boring drive sample is related to

disturbance during the sampling process.

Sandy lean clay to fat clay - (USC Soil Classification: CL to CH, AASHTO Soil

Classification: A-4 to A-7-5) - The clay is medium stiff to very stiff, moist, low to high

plastic and brown in color.

Laboratory tests conducted on samples of the clay indicate in-place moisture contents

ranging from 12 to 21 percent, in-place dry densities ranging from 99 to 111 pcf and

fines contents ranging from 51 to 69 percent. Atterberg Limits tests conducted on a

samples of the clay indicate liquid limits ranging from 22 to 58 percent and a plasticity

indices ranging from of 7 to 39 percent.

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A one-dimensional consolidation test conducted on a sample of the clay (at a depth of

29 feet) indicates it is non moisture sensitive when wetted under a constant pressure

of approximately 2,000 psf and slightly compressible under additional loading.

Silty sand - (USC Soil Classification: SM, Soil Classification: AASHTO A-2-4) - The silty

sand is dense to very dense, moist, fine-grained and light brown in color.

Laboratory tests conducted on samples of the silty sand indicate in-place moisture

contents ranging from 3 to 10 percent, in-place dry densities ranging from 97 to 117

pcf, a gravel content of 2 percent and fines contents ranging from 13 to 28 percent.

A direct shear test conducted on a sample of the silty sand in its existing condition

indicates a peak friction angle of 33 degrees and peak cohesion value 350 psf.

Several one-dimensional consolidation tests conducted on samples of the silty sand

indicate the material is non to slightly moisture sensitive (collapsible) when wetted

under constant pressures of approximately 1,000 and 2,000 psf and slightly

compressible under additional loading with the exception of the near surface soil in test

pit TP-5. The consolidation tests indicate the near surface soils tested are moderately

collapsible when wetted under a constant pressure of 500 psf. We anticipate a portion

of the measured collapse in the boring drive samples is related to disturbance during

the sampling process.

Poorly graded sand with silt - (USC Soil Classification: SP-SM, AASHTO Soil

Classification: A-2-4 to A-3 to A-1-b) - The poorly graded sand with silt contains

interbedded silty sand layers and occasional gravel. It is loose to very dense, moist to

slightly moist, fine-grained, and light brown in color.

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Laboratory tests conducted on samples of the poorly graded sand with silt indicate in-

place moisture contents ranging 1 to 8 from percent, in-place dry densities ranging

from 101 to 126 pcf, a gravel content ranging from 0 to 19 percent and fines contents

ranging from 5 to 12 percent.

Several one-dimensional consolidation tests conducted on samples of the poorly graded

sand with silt indicate it is non to slightly moisture sensitive (collapsible) when wetted

under constant pressures of approximately 1,000, 2,000 and 4,000 psf and slightly

compressible under additional loading with the exception of the near surface soil in test

pit TP-5 and Boring B-4. The consolidation tests indicate these near surface soils (in

the area of TP-5 and B-4) tested are moderately collapsible when wetted under a

constant pressure of 500 psf. We anticipate a portion of the measured collapse in the

boring drive samples is related to disturbance during the sampling process.

Poorly graded gravel with sand - (USC Soil Classification: GP, AASHTO Soil

Classification: A-1-a to A-1-b) - The poorly graded gravel with sand contains occasional

cobbles. It is medium dense to very dense, moist, sub-rounded gravel and brown in

color.

Laboratory tests conducted on samples of the poorly graded gravel with sand indicate

in-place moisture contents ranging from 2 to 3 percent, gravel contents ranging from

60 to 71 percent and fines contents ranging from 2 to 4 percent.

Logs of the subsurface conditions encountered in the test pits and borings are shown

graphically on Figures 3-9 with the Legend and Notes of Test Pits and Borings shown on

Figure 10. Results of the laboratory tests are also shown on Figures 3-9 and are summarized

on the Summary of Laboratory Test Results, Table 1 and the Summary of Chemical Test

Results, Table 2. One-dimensional consolidation test results are shown graphically on Figures

11-23. Direct shear test results are shown on Figures 24-29. Moisture-Density Relationship

(Proctor) and Gradation/Soil Classification Test Results are shown on Figures 30-35.

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Gradation Test Results are shown on Figures 36-45. R-value and chemical test results

subcontracted to outside laboratories are included in the Appendix of this report.

Laboratory test results were conducted in accordance with the following Test methods:

1. Atterberg Limits: AASHTO T89 and T90.

2. Gradation (Percent passing the No. 200 sieve): AASHTO T11.

3. Gradation (All sieves): AASHTO T27.

4. Soil Class: AASHTO M145.

5. One Dimensional Consolidation: AASHTO T216.

6. Moisture Density Relationship Test (Modified Proctor): AASHTO T180.

7. Direct Shear: AASHTO T236.

8. Chlorides: AASHTO T291.

9. Resistivity: AASHTO T288.

10. Water Soluble Sulfates: AASHTO T290 and SM4500E.

11. R-Value: AASHTO T190.

12. pH: AASHTO T289.

13. Moisture of Soils: AASHTO T265.

SUBSURFACE WATER

Subsurface water was not encountered in the borings and test pits by AGEC to the maximum

depth investigation, approximately 70 feet with the exception of boring B-12. Groundwater

was encountered at approximately 37 feet in Boring B-12 at the time of the exploration. This

corresponds to an elevation of approximately 1,558½ feet. Review of the “Baseline

Geotechnical Investigation” indicates groundwater was encountered at depths ranging from

approximately 67 to 75 feet below the existing grade. This corresponds to an elevation

ranging from approximately 1,557½ feet to 1,561 feet. Fluctuations in groundwater level

may occur over time. We anticipate the groundwater depth/elevation will likely remain

relatively constant throughout the year.

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PROPOSED CONSTRUCTION

We understand it is proposed to construct new, single span bridges at the I-15 mile post CL

120 interchange. The new, single span bridge (overpass) structures will be constructed

adjacent to the existing bridges (on either side, extending over Falcon Ridge Parkway) and will

be temporarily supported on driven pile foundations. The permanent bridge foundations are

proposed to consist of conventional spread footings and will be constructed concurrently to

support the new single span bridge structures in their permanent locations. The single span

bridges will allow for widening of the underpass and Falcon Ridge Parkway.

In order to construct the permanent foundations, the slope beneath the existing bridges will

require cutting on the order of 17 to 19 feet high to provide a location for the new

foundations. In order to safely support the proposed cut, we understand it is proposed to

construct a “staged”, temporary soil nailed wall with a reinforced or shot-crete facing on both

the north and south bridge abutments. The soil nailed wall will also extend to the east and

west to support permanent cuts on either side of Falcon Ridge Parkway.

It is our understanding that upon completion of the temporary soil nailing and the permanent

bridge foundations, the bridge structures will be moved onto and permanently attached to the

new foundations after removal of the existing bridge structures. The foundation walls will

subsequently be backfilled. The new bridge placement is planned to utilize a “Fast Track”

procedure to allow the process to be completed quickly and reduce road closure requirements.

In addition, we understand it is proposed to slightly re-align the existing on and off-ramps as

well as construct roundabouts on the east and west ends of Falcon Ridge Parkway. The

roundabouts will tie into the on-ramps, off-ramps, Falcon Ridge Parkway and Mesquite Blvd.

as shown on Figure 2. In addition, it is proposed to extend Falcon Ridge Parkway south to

Leavitt Lane. This will require fill depths of up to approximately 14 feet to fill eastern portion

of the eastern roundabout and the beginning of the roadway extension. The fill depths are

planned to taper down to near the existing grade at Leavitt Lane. The side slopes of the

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extensions will be graded at 4:1 (Horizontal:Vertical).

The following loading conditions and construction criteria have been provided by Horrocks

Engineers to facilitate our engineering analysis:

1. Temporary foundations will consist of HP 14X89 or HP 14X117 H-piles.

2. Unfactored axial load on the temporary pile foundations = 205 kips per pile.

3. Unfactored axial load on temporary support piles = 70 kips.

4. Unfactored lateral load on the temporary foundations = 12 kips per pile.

5. Strength 1 loading applied to the permanent foundations = 87.4 kips/foot.

6. Service 1 loading applied to the permanent foundations = 66.0 kips/foot.

7. Estimated preliminary foundation footing size = 12 feet wide by 70 feet long.

If the proposed construction or building loads are significantly different from what are

described above, we should be notified so that we can reevaluate the recommendations given.

RECOMMENDATIONS

Based on the subsurface conditions encountered, the referenced Baseline Geotechnical

Investigation, laboratory test results and the proposed construction, the following

recommendations are provided.

A. Site Grading

Based on a description of proposed grading and the preliminary cut/fill map provided

by Horrocks, the following table provides a brief description of the proposed grading:

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Location Description of proposed grading

Permanent bridge foundation Requires cuts on the order of 17 to 19 feet

West roundabout and Underpass - Falcon Ridge

Parkway

Constructed near the existing grade with significant

cuts on either side.

Falcon Ridge Parkway and east of east

roundabout

Requires up to 14 feet of fill tapering to near the

existing grade at Leavitt Lane

East end of east roundabout Requires up to 14 feet of fill

North bound off ramp Will be cut below the existing grade

South bound on and off ramps and north bound

on ramp

Shallow fill or constructed near the existing grade

Bridge approaches Near the existing grade

1. Subgrade Preparation

a. Grubbing: Portions of the proposed alignment contain near surface

vegetation or cultivated soil, particularly along the portions of the on/off

ramps and along the alignment of the east end of Falcon Ridge Parkway.

Prior to placing site grading fill to support roadways, the existing

organics and soil containing roots and organics should be removed. We

anticipate the thickness may vary from approximately 2 to 6 inches in

areas where vegetation is observed. Clearing and grubbing should

follow the requirements of Section 201 of the NDOT Standard

Specifications for Road and Bridge Construction.

b. General: Prior to placing fill, the existing asphalt should be removed the

full depth. Consideration may be given to roto-milling the pavement

section to the full depth and re-using the material for the embankment

fill beneath Falcon Ridge Parkway or as base course beneath roadways,

if acceptable. Use of cold millings as a base layer (in the bottom half)

should be in accordance with the “Pull Sheet” for Section 302 of the

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NDOT Standard Specifications for Road and Bridge Construction. Cold

millings used as embankment fill should meet the requirements of

Section 203 of the NDOT Standard Specifications for Road and Bridge

Construction.

Subsequent to grubbing and asphalt/base removal, undiscovered loose

soils or disturbed soils should also be removed. Prior to placing fill,

base course or concrete, the exposed subgrade should be scarified at

least 8 inches, moisture conditioned and compacted to at least 90

percent of the maximum dry density as determined by Test Method No.

Nev. T101.

c. Dry/Collapsible soil removal: AGEC’s laboratory testing and observations

indicate the near surface soil in the area just east of the cultivated field

(area not currently cultivated) is loose and/or moderately collapsible

when wetted (Test Pit TP-5). The zone appears to extend to

approximately 4 feet below the existing grade. We estimate that on the

order of c inch of post construction settlement (of the roadway) may

occur for each foot of the underlying collapsible soil which is wetted

after construction.

To reduce the potential post construction settlement (resulting from

collapse), we recommend the exposed subgrade be overexcavated (in

this area) to remove the natural soils at least 2 feet below the existing

grade. In addition, the near surface soils along the east edge of

Mesquite Blvd (Boring B-10) were also observed to be loose. We

recommend this area be overexcavated to remove the natural soils at

least 1 foot below the existing grade. The approximate locations which

require additional overexcavation are shown on Figure 2. The

overexcavation should extend at least 2 feet beyond the limits of edge

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of roadway or the embankment.

Subsequent to overexcavation (one or 2 feet) and prior to placing fill or

base course, the exposed subgrade should be scarified 8 inches,

moisture conditioned and compacted to at 90 percent of the maximum

dry density as determined by Test Method No. Nev. T101. The removed

soil may be replaced in properly compacted lifts.

2. Excavation

We anticipate excavation of the on-site soils can be accomplished with typical

excavation equipment. Excavations of temporary cut slopes should be sloped

in accordance with OSHA Soil Site Class C. This will require the slopes to be

graded at a maximum slope of approximately 1½:1 (horizontal to vertical). As

an alternative, the slopes may be reinforced, shored or retained. We understand

the cut slopes along the north and south sides of Falcon Ridge Parkway

(beneath the bridge) are proposed to be reinforced with a soil nails and a

reinforced facing or shot-crete. The following section provides details which

should be considered for the soil nailed wall design and construction. We

understand the final soil nailed wall design will be provided by others.

3. Soil Nailed Walls

During and after construction, a soil nailed wall and the soil behind it tend to

deform outwards. The deformation has two components: (1) During excavation

and (2) after the soil nails are constructed due to mobilization of the soil to

achieve capacity (interaction between the soil and nail).

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We understand this movement will not be critical in the permanent soil nailed

wall locations where the wall is not supporting the existing bridge spread

footing. Controlling the anticipated movement will be necessary where the

temporary soil nailed wall is constructed adjacent and beneath the existing

bridge footings.

Due to the critical nature of the temporary soil nailed wall and facing system,

it is recommended that the proposed design include construction techniques

and analysis to control movement at the face and subsequent settlement of the

adjacent bridge foundation to allow the bridge to remain in service.

The following options may be considered to reduce potential movement of the

foundation due to lateral movement/bending of the soil nailed wall:

a. The soil nails may be drilled, partially grouted along their length and pre-

tensioned to mobilize some of the nail strength while reducing the soil

mass deformation near the wall face.

b. The spacing of the soil nails may be decreased to reduce the stresses

developed on each nail to reduce mobilization of the soil.

c. The length of the soil nails may be increased to reduce the stresses

developed on each nail which will likely reduce mobilization of the soil.

d. The soil nailed wall facing may be designed and constructed to provide

increased stiffness to assist in reducing movement at the face.

e. The face may be battered.

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Additional recommendations which should be considered for design and

construction of the soil nailed walls are provided below:

a. Preliminary analysis by AGEC indicates additional nail length may be

necessary for the temporary soil nailed walls to increase factors of

safety against failure due to potential deep seated failure resulting from

the underlying looser sand.

b. The construction of the soil nailed walls should incorporate staged

construction methods. This method will be particularly critical adjacent

to the existing bridge footings. We recommend the first cut be

conducted only to allow for installation of the first row of soil nails

beneath the existing spread footings. This may be accomplished by

cutting “notches” for each nail to assist in minimizing movement/caving

until the first row of nails are complete and have achieved strength.

Prior to cutting for the second row, the reinforced wall facing should be

constructed over the first row and allowed to achieve strength. This

process may require alternating between the north and the south

abutment.

c. The soil nailed walls should be designed in accordance with the

referenced FHWA guidelines. Loading combinations (Including dead

load, live load and earth quake) and acceptable factors of safety should

be implemented in the design as provided by FHWA.

d. The soil nailed wall design should consider internal stability, external

stability and global stability in the analysis during various stages of the

construction.

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e. Corrosion of the permanent soil nailed wall should also be assessed. A

Summary of Chemical Laboratory Test Results is attached.

f. We understand the NDOT has expressed concern regarding drainage

behind the soil nailed wall face. We understand a geo-composite drain

will be placed behind the facing and will be specified in the final soil nail

design.

g. Based on observations by AGEC during our field investigation, we

anticipate that the staged cut heights should remain stable temporarily

during construction. We recommend the length of the exposed cut face

be minimized during the staged construction process and the slope face

should be excavated/cut in front of the soil nailing equipment as soil

nailing progresses. All exposed cuts should be nailed the same day as

excavation occurs. Excavations should be made with care to reduce

disturbance. If caving of the cut occurs during drilling or excavation, the

nails may need to be drilled/installed though a stabilizing berm.

h. Due to the granular nature of the soils, casing may be necessary during

drilling operations. The soils behind the proposed soil nailed walls

consist of sandy fill which contains some clay which may allow the nail

borings to remain open.

I. Inspections and load tests should be accomplished (prior to and during

construction) in accordance with the previously referenced FHWA

publications and the “Pull Sheet” for Section 644 - Soil Nail Retaining

Walls.

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j. The soil nail retaining walls should be constructed in accordance with

the Pull Sheet for Section 644 - Soil Nail Retaining Walls. Particular

attention should be paid to the excavation procedures as provided in

section 644.03.04 of the referenced “Pull Sheet”.

4. Fill Slopes/Embankments

We understand an embankment will be constructed to support the east

alignment of Falcon Ridge Parkway and the east end of the adjacent

roundabout. The fill depths are proposed to be approximately 14 feet tapering

down to near the existing grade at Leavitt Lane. Fill slopes constructed with

the on-site soil should be constructed no steeper than 2:1 (horizontal:vertical).

The on-site soils will be susceptible to erosion. We understand the side slopes

on either side of the embankment will be constructed at a 4:1 slope to reduce

the potential for erosion.

Fill slopes should be constructed to assure a properly compacted slope face.

This may be accomplished by wheel rolling the exposed face during grading.

As an alternative, the compacted face may be constructed by overbuilding the

slope and then cutting back the slope face to the desired grade to provide a

properly compacted slope face.

Fill placed on an existing slope should be benched into the existing slope to

provide a level surface for placement and compaction of the fill. This will also

serve to the “key” the fill into the slope and to potentially reduce differential

movement. This will be critical when placing fill to construct the east

roundabout and the east side of Mesquite Blvd. The west portion of the

roundabout is near the existing grade while the east portion requires up to

approximately 14 feet of fill. Fill should be placed in accordance with Section

203.03.12 of the NDOT Standard Specifications for Road and Bridge

Construction.

Page 20


AGEC conducted analysis to estimate the potential settlement of the

embankment resulting from the densification of the underlying support soils.

The proposed embankment will support Falcon Ridge Parkway from the east

roundabout to Leavitt Lane and varies from approximately 14 feet high and

tapers down to near the existing grade at Leavitt Lane.

The estimated settlement was calculated using the Hough method for normally

consolidated, cohesionless soils and is based on a layered profile which was

developed from corrected penetration values (N160). A representative profile

was developed utilizing borings B-11, B-12 and B-13 which indicates alternating

layers of dense and very dense of sand and gravel.

The following table summarizes the estimated settlement of the embankment

depending on the fill depth:

Embankment Height (ft) Estimated Settlement (inches)*

14 1½

10 1c

5 b

*Settlement estimates assume the subgrade beneath the fill is properly prepared.

We predict the estimated settlement will occur rapidly during the construction

process due to the granular nature of the underlying support soils and should

not affect the performance of the roadway or embankment provided the fill is

properly compacted.

Page 21


5. Imported Materials

In accordance with the NDOT Standard Specifications for Road and Bridge

Construction, the table below provided material specifications for soils which

will be imported site grading and structural fill.

Fill Type/Use Material Requirements

Borrow / Embankment and SiteGrading

Non-expansive granular soilR value $ 45

Selected Borrow / Embankmentand Site Grading - Surfacebeneath paved areas

Non-expansive granular soilR value $ 45Percent Passing 3" Sieve: 100

Backfill / Behind retainingwalls/below grade structuresunless granular backfill isspecified

Percent Passing 3" Sieve: 100

Granular Backfill / Behindretaining walls/below gradestructures

Percent Passing 3" Sieve: 100Percent Passing No. 4 sieve: 35 - 100Percent Passing No. 30 sieve:20 - 100Percent Passing No. 200 sieve 0 - 12LL = 35 max., PI = 10 max.pH = 5 to 9 - Concrete and steel, pH 4.0 min. - AluminumResistivity = 1000 ohm-cm min. - Concrete and steelResistivity = 500 ohm-cm min. - Aluminum

Shouldering Material Approved base aggregate - See NDOT StandardSpecifications for Bridge and Road Construction

Base Aggregate / AsphaltSupport, Concrete Slab and curbSupport

Approved base aggregate - See NDOT StandardSpecifications for Road and Bridge Construction

Base Aggregate / Drain Rock Crushed AggregatePercent Passing 2" Sieve: 100Percent Passing the No. 200 Sieve: 0-2

All materials should be free of sod and organicsLL=Liquid Limit, PI = Plasticity Index

Page 22


6. Material Suitability of On-site Soils

AGEC conducted laboratory testing on soil samples obtained during our field

investigation to determine suitability for use as fill. Areas included the cut

behind the bridge abutments (Borings B-4, B-5 and B-7) and the infield cut areas

between the north bound traffic lane and the north bound off ramp (Test Pits

TP-1, TP-2 and TP-3).

The following laboratory test results were conducted by AGEC and are

provided:

AASHTO Soil Classification = A-2-4.

USCS Soil Classification = Mainly SM, and occasional SP-SM.

R-value = 64 to 75.

PI = non-plastic.

Water Soluble Sulfates = 300 to 1,200 ppm.

pH= 8.1 to 9.0.

Resistivity = 450 to 1,400 ohm-cm.

The following summary of the particle size distribution is provided:

Sieve Size Percent Passing

3" 100

No. 4 70 to 99

No. 30 56 to 98

No. 200 9 to25

Page 23


Based the listed laboratory test results, the on-site soils encountered are

suitable for use as Borrow, Selected Borrow and Backfill in accordance with

Sections 203 and 207 of the NDOT Standard Specifications for Bridge and

Road Construction and “Pull Sheets” from the contract documents. Testing

indicates most of the soil tested does not meet the No. 200 sieve for Granular

Backfill and a portion of the resistivity results are too low (3 of 5 are less than

1,000). A layer of lean clay was encountered at a depth of 10 feet in Test Pit

TP-2. This layer of soil is not suitable for use as Borrow, Selected Borrow and

Backfill.

AGEC’s test results correlate with results provided in the Baseline Geotechnical

Investigation with the exception of resistivity. AGEC’s resistivity results are

generally lower in magnitude, thus indicating more corrosive soils. We

anticipate this may be due to the different test methods utilized and/or

shallower depths that AGEC’s samples were obtained. NDOT followed Nevada

test methods while AGEC followed AASHTO test methods. Further, NDOT

samples ranged from 13 to 36 feet below the existing grade while AGEC’s

samples ranged from 1 to 14 feet below the existing grade.

7. Compaction

Compaction of fill materials placed at the site should equal or exceed the

following percentages:

Area/Location Compaction

Structure foundation subgrade $ 95%

Wall backfill $ 95%

Embankment $ 90%

Pipe backfill $ 90%

Base Course $ 95%

Natural Subgrade $ 90%

Page 24


Compaction of materials placed at the site should be compared to the maximum

dry density as determined by Test Method No. Nev. T101. To facilitate the

compaction process, fill should be compacted at a moisture content within 2

percent of the optimum moisture content as determined by Test Method No.

Nev. T101.

Fill placed for the project should be frequently tested to verify compaction. The

moisture content of the on-site fill soils and natural soils are varied from below

to above the optimum moisture content. Fill should be placed in loose lifts

which do not exceed 8-inches in thickness.

8. Drainage

The ground surface should be sloped to provide positive site drainage during

and following construction. Maintaining positive site drainage during and

following construction should be implemented. Ponding of water should be

minimized. Methods should also be implemented to reduce infiltration of water

into the subsurface soils behind retaining structures.

The collection and diversion of drainage away from the pavement surface is

extremely important to the satisfactory performance of the pavement section.

Proper drainage should be provided

B. Permanent Shallow Foundations

The proposed bridge overpass may be permanently supported on conventional spread

footings as provided below:

1. Bearing Resistance

Footings/foundations may designed using the factored bearing resistances

plotted on Figure 46.

Page 25


The following table summarizes resistance factors used to calculate the factored

bearing resistances provided on Figure 46:

Limit State Resistance Factor (Nb)*

Service I 1.0

Strength I 0.45

Extreme Event I 1.0

*In accordance with Section 10 (specifically Sections 10.5.5.1, 10.5.5.2 and 10.5.5.3) of AASHTO LRFD

Bridge Design Specifications, 2010.

Bearing capacity analysis in the strength limit state is based a theoretical

analysis method (Section 10.6.3.1 of AASHTO LRFD Bridge Design

Specifications, 2010) for cohesionless soils. This method uses corrected

penetration values measured in the field during drilling/sampling to estimate the

soil strength (friction angle) and associated bearing capacity factors. Direct

shear data was compared the estimated soil friction angle.

The service limit state bearing values correlate to an estimated total settlement

of approximately 1 inch and a differential settlement of approximately ½ inch

after the bridge structure is placed on the permanent foundation.

Prior to placing concrete, we recommend the exposed subgrade be compacted

to at least 95 percent of the maximum dry density as determined by Test

Method No. Nev. T101.

Page 26


A 12 foot wide footing was selected based on the factored bearing resistances

provided on Figure 46. With this footing width, the following table summarizes

the limit states and associated bearing resistances:

Location Bearing Soil

Limit State*

Service Limit I Strength Limit I Extreme Event I

qn

(ksf)

qr

(ksf)

qn

(ksf)

qr

(ksf)

qn

(ksf)

qr

(ksf))

All

abutments

Compacted

sand

5.5 5.5 17.8 8.0 16.5 16.5

*Where qn = nominal bearing resistance and qr = factored bearing resistance.

2. Settlement

AGEC conducted analysis to estimate the potential settlement of the

foundations to establish the Service Limit State bearing resistance resulting

densification of the underlying support soils.

The estimated settlement was calculated using the Hough method for normally

consolidated, cohesionless soils and is based on a layered profile which was

developed from corrected penetration values (N160). A representative

subsurface profile was developed based on the loosest soil conditions after

reviewing SPT values measured/corrected for AGEC Borings B-4, B-5 and B-7

and NDOT Borings RMI-1 and RMI-4. Corrected penetration values indicated

AGEC Boring B-5 contained the loosest soils. This boring profile was used to

provide a conservative settlement estimate for the subsurface conditions

encountered at various bearing pressures.

Page 27


Based on the analysis described above and the proposed construction, we

estimate total settlement for the permanent foundations designed as indicated

above to be approximately 1 inch after the bridge superstructure is placed on

the permanent foundation. Differential settlement is estimated to be

approximately ½ inch. Foundation settlement will likely occur rapidly due to the

presence of granular soils supporting the foundation.

3. Footing Embedment

Spread footings should be embedded such that at least 2 feet of cover soil is

provided over the footings. This should be measured from the ground surface

to the top of the footing.

4. Foundation Base

The base of foundation excavations should be cleared of loose or deleterious

material prior to concrete placement.

5. Construction Observation

A representative of the geotechnical engineer of record should observe footing

excavations prior to concrete placement.

C. Temporary Pile Foundations

The proposed bridge super structure may be supported on temporary foundations

consisting of driven H-piles (during construction of the bridge structure) as provided

below:

Page 28


1. Pile Axial Capacity

The axial capacity of the temporary piles was derived using a theoretical

analysis method for cohesionless soils. This method uses corrected penetration

values measured in the field during drilling/sampling to estimate the soil strength

(friction angle), the critical depth, skin friction parameters and the associated

bearing capacity factors.

Ultimate axial capacity curves (ultimate capacity vs depth) and ultimate uplift

capacity curves are provided on Figure 47. A depth of “0" feet on the capacity

curves shown on Figure 47 refers to the ground surface elevation at each pile.

2. Pile Length

We estimate the piles will need to be driven on the order of 25 feet to achieve

the necessary capacity.

3. Estimated Settlement

The pile settlement was estimated using 2 methods for piles bearing in the zone

of loose to medium dense sand. The first method (by Hannigan) models a

group of piles which act as a large spread footing at b the pile length (See

AASHTO LRFD Bridge Design Specifications, 2010, Section 10.7.2.3). This

method assumes the total load at the surface is transferred to this depth and

does not include skin friction capacity because of the grouped pile affect. It is

our professional opinion that this method would overestimate settlement for

piles with a relatively large spacing.

A second method (By Mindlin) was utilized to model the relatively large pile

spacing for the proposed temporary foundations. This method assumes the pile

capacity includes skin friction which varies depending on the pile spacing. This

method calculates a load or stress transferred to the tip of the pile which is

reduced due to the capacity achieved with skin friction resulting in less

estimated settlement.

Page 29


With the anticipated axial loads and pile lengths, the following table summarizes

the estimated settlement for piles bearing in the underlying loose to medium

dense sand for each of the methods:

Method Estimated Total Settlement (inches) Differential

Settlement

(inch(es))Temp Abutment Temp. Support

Hannigan ¾ to 1½ ½ ½ to 1

Mindlin ½ ¼ <½

It is our professional opinion that the Mindlin method more accurately models

the proposed construction and we anticipate the settlement for piles bearing on

loose to medium dense sand will be on the order of ½ inch. This would include

the North bound abutment - south side. Tip elevations by Horrocks indicate the

piles supporting the North bound abutment - north side and both of the South

bound abutments will bear on or near the underlying dense to very dense sand.

We estimate the total settlement for these abutment piles will be less than ½

inch.

We further stress that these methods are empirical and only provide

“estimates”. The anticipated settlement may be verified/measured in the field

prior to construction by driving a pile to the design depth and conducting a load

test to measure the associated deflection under the proposed loads.

If the risk of settlement for piles bearing in the loose to medium dense sand (as

described above) is not acceptable, the piles may be driven to bear in the

underlying dense to very dense sand. The following Table summarizes the

approximate elevation where the relatively dense sand was encountered.

Page 30


Boring No.Approximate elevation of dense to

very dense sand (feet)

AGEC B-4 1,586

AGEC B-5 1,580

AGEC B-7 1,591

NDOT RMI-1 1,573

NDOT RMI-4 1,575

4. Lateral Capacity

The L-pile analysis was conducted using loads provided by Horrocks Engineers

and the listed soil parameters provided in the following table to model the

subsurface profile. The parameters are based on laboratory test data and

corrected penetration values measured during sampling.

Depth (ft) Soil Type Unit wt (pcf) N (")cohesion

(psf)Kh (pci)

0-25 SM 110 37 0 130

25-55 SM 110 34 0 100

55-65 SM 110 42 0 150

65-70 ML/CL 110 0 2,000 550

Based on the L-pile analysis, we recommend a minimum pile length of 20 feet

for lateral stability. Lateral capacity curves (Pile Head Deflection, Maximum

bending moment and p-y curves) are shown on Figures 47-53.

Page 31


D. Concrete Slab-on-Grade/Curb

Concrete slabs should be supported on a properly prepared and compacted subgrade

as recommended in the Subgrade Preparation and Compaction sections of this report,

pages 13-15 and 23-24, respectively.

A 4-inch layer of free-draining gravel or approved road base material should be placed

below concrete slabs for ease of construction, to promote even curing of the slab

concrete and to provide a firm and consistent subgrade.

E. Lateral Earth Pressures

1. Lateral Resistance for Footings

Lateral resistance for spread footings placed on compacted sand is controlled

by sliding resistance developed between the footing and the subgrade soil. An

ultimate friction value of 0.50 may be used in design for ultimate lateral

resistance of footings bearing on properly compacted on-site sand. Prior to

placing concrete, we recommend the exposed subgrade be compacted to at

least 95 percent of the maximum dry density as determined by Test Method No.

Nev. T101. Sliding resistance for footings should be reduced using a resistance

factor NJ=0.9.

2. Subgrade Walls and Retaining Structures

The following equivalent fluid weights are given for design of subgrade walls

and retaining structures. The active condition is where the wall moves away

from the soil. The passive condition is where the wall moves into the soil and

the at-rest condition is where the wall does not move. The values listed below

assume a horizontal surface adjacent the top and bottom of the wall.

Page 32


Soil Type Active At-Rest Passive

On-site sand 35 pcf 50 pcf 300 pcf

Earth pressure coefficient 0.28 0.44 -

It should be recognized that the above values account for the lateral earth

pressures due to the soil and level backfill conditions and do not account for

hydrostatic pressures. Lateral loading should be increased to account for

surcharge loading if present above the wall and within a horizontal distance

equal to the height of the wall or if the ground surface slopes up away from the

wall.

Lateral loading should be increased to account for surcharge loading if

structures are placed above the wall and are within a horizontal distance equal

to the height of the wall or if the ground surface slopes up away from the wall.

Care should be taken to prevent percolation of surface water into the backfill

material adjacent to the retaining walls. The risk of hydrostatic buildup can be

reduced by placing subdrains behind the walls consisting of free-draining gravel

wrapped in a filter fabric. As an alternative, weep holes may be provided every

10 feet at the base of the wall to assist in drainage of water.

3. Seismic Conditions

Under seismic conditions, the equivalent fluid weight should be modified as

follows according to the Mononobe-Okabe method assuming a level backfill

condition:

Page 33


Lateral Earth

Pressure Condition

Seismic Event

*PGA = 0.23g - 1,000 yr event

Active 18 pcf increase

At-rest ** 0 pcf increase

Passive 41 pcf decrease

* The PGA is adjusted for site conditions (Site Class D), but not reduced as stated on page 11-20 (AASHTO

LRFD Bridge Design Specifications) due to the critical nature of the structure.

** The total equivalent fluid weights (static plus seismic increase) in an “at-rest” condition should not exceed

the total active condition (static plus seismic increase).

We recommend the resultant from the seismic forces be placed at the mid-

height of the retaining wall in accordance with LRFD Methods.

4. Resistance Factors

The values recommended above for active and passive conditions assume

mobilization of the soil to achieve the soil strength. Appropriate resistance

factors for structural analysis for such items as overturning and sliding

resistance should be used in design.

F. Seismicity

Seismic design parameters are provided below for the 1,000 year seismic event as

requested:

Page 34


Description

Seismic Event

1,000 yr event (.7% PE in 75 yrs)*

2010 AASHTO Site Class D**

Site Location Clark County, Nevada

PGA - Site Class B 0.15g

Ss (0.2 second period) - Site Class B 0.40g

S1 (1 second period) - Site Class B 0.15g

FPGA 1.50

Fa 1.48

Fv2.2

SD1 0.33g (AASHTO Seismic Zone 3)

*These values (tabulated in the 2008 NDOT Structures Manual for Clark County) are approximately equivalent to

the Site Specific (by Coordinates) 2,500 year event.

** Based on weighted average (N1)60 values and REMI survey data.

G. Liquefaction

Liquefaction is a condition where a soil loses strength due to an increase in soil pore

water pressures during a dynamic event such as an earthquake. Research indicates

that the soil type most susceptible to liquefaction during a severe seismic event is

loose, clean sand. For the sand to liquefy, it must be located beneath the groundwater

level. The liquefaction potential for soil tends to decrease with an increase in fines

content and density.

Based on our field investigation and the baseline Geotechnical Report (Reference No.

2), the following subsurface conditions exist at the subject site:

1. The groundwater level is on the order of 70 feet below the existing grade (see

Reference No. 2).

Page 35


2. The subsurface soils generally consist of medium dense to very dense sand.

3. The subsurface soils located beneath approximately 30 to 50 feet are very

dense with an average (N1)60 greater than 50 blows per foot.

Based on these conditions, it is our opinion the subsurface soils above the groundwater

level are generally non-liquefiable during a severe seismic event and the soils located

beneath the groundwater level present a very low potential for liquefaction during a

severe seismic event.

H. Water Soluble Sulfates and Cement Type

Laboratory tests results indicate a water soluble sulfate concentration ranging from 300

to 1,200. According to Table 4.2.1 of ACI 318-08, the on-site soils posses a

“moderate” severity for corrosion of buried concrete structures. Therefore, we

recommend that concrete that will be in contact with the on-site soil contain Type V

sulfate resistant cement with 20% Type F pozzolan using a sulfate exposure category

of “moderate”. Further, this is in accordance with the NDOT Standard Specifications

for Road and Bridge Construction.

I. Corrosion

Corrosion tests were performed on samples of the on-site soils. Results of laboratory

tests indicate a chloride range of 14 to 161 ppm and a pH range of 8.1 to 9.0.

Resistivity tests conducted in the laboratory indicate resistivities ranging from 450 to

1,400 ohm-cm at relatively high water contents. The test results indicate the on-site

soil is corrosive to buried metal, particularly under high moisture conditions which

would result from poor drainage. Controlling drainage and infiltration into the

subsurface soils will reduce corrosion.

Page 36


J. Construction Testing and Observation

We recommend testing fill and concrete materials at a frequency which meets or

exceeds project specifications NDOT Standard Specifications for Road and Bridge

Construction. We also recommend the following testing and observations be done as

a minimum.

1. Verify the subgrade is prepared as recommended beneath fill areas.

2. Conduct compaction testing on fill placed in accordance with the State of

Nevada DOT Standard Specifications for Road and Bridge Construction.

3. Verify the subgrade beneath the permanent spread footings is properly

compacted.

4. Verify the capacity of the pile foundations using PDA testing or another

approved method.

5. Conduct special inspections (concrete and steel) as required by LRFD and the

State of Nevada DOT.

A final summary report may be provided for the structures if the recommendations in

this report are followed and verified by AGEC.

Page 37


LIMITATIONS

This report has been prepared in accordance with generally accepted soil and foundation

engineering practices in the area for the use of the client for design purposes. The conclusions

and recommendations included within the report are based on the information obtained from

the borings drilled at the approximate locations indicated on the site plan, the data obtained

from laboratory testing, the referenced Baseline Geotechnical Investigation and our experience

in the area. Variations in the subsurface conditions may not become evident until additional

exploration or excavation is conducted. If the proposed construction, subsurface conditions

or groundwater level is found to be significantly different from what is described above, we

should be notified to reevaluate our recommendations.

APPLIED GEOTECHNICAL ENGINEERING CONSULTANTS, INC.

Arnold DeCastro, P.E.

Reviewed by: Jared Hanks, P.E.

AD/sd P:\2010 Project Files\2010 Project Files\2100900\2100948 - West Interchange, Mesquite\2100948.report.wpd

cc Mike Dobry, P.E. - Horrocks Engineers, [email protected] Matt Horrocks, P.E. - Horrocks Engineers, [email protected] Derek Stonebraker, E.I.T. - Horrocks Engineers, [email protected]

sdabbs

sdabbs

7.58 8 8 8 8

7.56.5

7.0

8.5

10.0

13.0

16.5 16.5 16.5 16.5 16.5 16.5

6

8

10

12

14

16

18

d Be

aring Re

sistan

ce (k

sf)

Factored Bearing Resistance vs Effective Footing Width

Strength Limit State

Service Limit State ‐ Stotal = 1 inch, Sdiff = 1/2 inchExtreme Limit State

Project No. 2100948 Applied Geotech Figure 46

33.75

4.5

66.5

5.54.5 4.5 4.5

0

2

4

6

0 5 10 15 20

Factored

Effective Footing Width (ft)

Where S diff= Differential Settlement.

Note: Bearing resistances are calculated for asouthbound bottom of footing elevation (BOF) = 1,606.5 and a nouthbound BOF elevation = 1,606.0.

0

10

20

30

40

50

60

200 250 300 350 400 450 500 550

Ultimate Axial Capacity (Kips) vs Depth

HP 14X89

HP 14X117

Depth

ft

Note: "0" feet on the verticalaxis refers to the ground surface at each pile.

0

50 100 150 200 250 300

Ultimate Uplift Capacity (Kips) vs Depth

0

10

20

30

40

50

60

HP 14X89

HP 14X117

Depth

ft

Note: "0" feet on the vertical axis refers to the ground surface at each pile.


0.4

0.5

0.6

0.7

ead

Def

lect

ion

(inch

es)

Pile Head Deflection


0

0.1

0.2

0.3

0 4 8 12 16 20 24

Pile

He

Lateral Load (kips)

HP 14x89 (Strong Direction)

HP 14x89 (Weak Direction)



600

800

1000

1200

m M

omen

t (in

ch-k

ips)

Maximum Moment


0

200

400

0 4 8 12 16 20 24

Max

imum

Lateral Load (kips)





0

10

Dep

th (f

eet)

Pile DeflectionHP 14x89 (Strong Direction)


20

30-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

D

Deflection (inches)

3 kips

6 kips

9 kips

12 kips

15 kips

18 kips

21 kips

Lateral Load

0

10

Dep

th (f

eet)

Pile DeflectionHP 14x89 (Weak Direction)


20

30-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

D

Deflection (inches)

3 kips

6 kips

9 kips

12 kips

15 kips

18 kips

21 kips

Lateral Load

0

10

Dep

th (f

eet)

Pile DeflectionHP 14x117 (Strong Direction)


20

30-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

D

Deflection (inches)

3 kips

6 kips

9 kips

12 kips

15 kips

18 kips

21 kips

Lateral Load

0

10

Dep

th (f

eet)

Pile DeflectionHP 14x117 (Weak Direction)


20

30-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

D

Deflection (inches)

3 kips

6 kips

9 kips

12 kips

15 kips

18 kips

21 kips

Lateral Load

* Test remolded at approximately 95% compaction near the optimum moisture content.** Test conducted at its exiting moisture content and density. Page 1 of 5

Applied Geotechnical Engineering Consultants, Inc.

Table 1 - Summary of Laboratory Test Results

I-15 Milepost CL 120 Interchange Project No. 2100948

SampleLocation

NaturalMoistureContent

(%)

NaturalDry

Density(pcf)

Gradation Atterberg Limits Direct ShearMoisture-Density

Relationship

R-v

alue

@ 3

00 p

siEx

udat

ion

Pres

sure

Soil Type/ClassificationTes

t Pi

t/Bor

ing

No.

Dep

th (ft

)

Gra

vel (

%)

San

d (%

)

Silt

/Cla

y (%

)

LiquidLimit(%)

PlasticIndex(%) C

ohes

ion

(psf

)

Fric

tion

Ang

le (°)

MaximumDry

Density(pcf)

OptimumMoistureContent

(%)

TP-1 1-4 0 81 19 NP 340* 42* 122.5 11.0 64 Fill; silty sand mixed with some clay (SM); A-2-4

TP-1 3 9 106 23 Fill; silty sand mixed with some clay (SM); A-2-4

TP-1 11 8 28 Silty sand (SM); A-2-4

TP-2 1-4 15 70 15 NP 129.5 9.0 65 Fill; silty sand with gravel mixed with some clay(SM); A-2-4

TP-2 10½ 12 0 46 54 22 7 Sandy lean clay (CL); A-4

TP-3 1-4 0 81 19 NP 440* 40* 122.5 11.0 Fill; silty sand mixed with some clay (SM); A-2-4

TP-3 2½ 9 106 24 Fill; silty sand mixed with some clay (SM); A-2-4

TP-3 6 8 Fill; silty sand mixed with some clay (SM); A-2-4

TP-3 9 8 21 Fill; silty sand mixed with some clay (SM); A-2-4

TP-4 5 2 60 38 2 Poorly graded gravel with sand (GP)A-1-a

TP-5 1½ 7 102 17 Silty sand (SM); A-2-4

TP-5 4 4 101 11 Poorly graded sand with silt (SP-SM); A-2-4

TP-5 7-11 3 0 95 5 Poorly graded sand with silt (SP-SM); A-3

B-1 0-3 15 73 12 NP 128.5 7.5 67 Fill; silty sand with gravel (SM); A-2-4




SampleLocation


(%)

NaturalDry

Density(pcf)


Relationship

R-v

alue

@ 3

00 p

siEx

udat

ion

Pres

sure


t Pi

t/Bor

ing

No.

Dep

th (ft

)

Gra

vel (

%)

San

d (%

)

Silt

/Cla

y (%

)

LiquidLimit(%)

PlasticIndex(%) C

ohes

ion

(psf

)

Fric

tion

Ang

le (°)

MaximumDry

Density(pcf)


(%)


B-1 4 1 106 Poorly graded sand with silt (SP-SM); A-2-4

B-2 2½ 8 111 20 NP Fill; silty sand mixed with some clay (SM); A-2-4

B-2 5 5 110 15 Fill; silty sand mixed with some clay (SM); A-2-4

B-3 2½ 6 113 15 Fill; silty sand mixed with some clay (SM); A-2-4

B-3 5 4 109 16 NP Fill; silty sand mixed with some clay (SM); A-2-4

B-4 1-7 28 58 14 NP 550* 42* 134.0 6.5 75 Fill; silty sand with gravel mixed with some clay(SM); A-2-4

B-4 4 5 15 Fill; silty sand mixed with some clay (SM); A-2-4

B-4 6½ 780** 32** Fill; silty sand mixed with some clay (SM); A-2-4


B-4 14 9 16 NP Fill; silty sand mixed with some clay (SM); A-2-4

B-4 24 8 117 19 Silty sand (SM); A-2-4

B-4 34 3 104 6 Poorly graded sand with silt (SP-SM); A-3

B-4 44 4 105 12 Poorly graded sand with silt (SP-SM); A-2-4

B-4 49 5 2 83 15 Silty sand (SM); A-2-4




SampleLocation


(%)

NaturalDry

Density(pcf)


Relationship

R-v

alue

@ 3

00 p

siEx

udat

ion

Pres

sure


t Pi

t/Bor

ing

No.

Dep

th (ft

)

Gra

vel (

%)

San

d (%

)

Silt

/Cla

y (%

)

LiquidLimit(%)

PlasticIndex(%) C

ohes

ion

(psf

)

Fric

tion

Ang

le (°)

MaximumDry

Density(pcf)


(%)


B-4 54 6 110 13 Silty sand (SM); A-2-4

B-4 64 14 105 51 Sandy fat clay (CH); A-7-5

B-5 1-7 25 66 9 NP 490* 42* 130.5 7.5 Fill; poorly graded sand with silt and gravel mixedwith some clay (SP-SM); A-3

B-5 4 6 108 13 NP Fill; silty sand mixed with some clay (SM); A-2-4

B-5 9 6 1 83 16 Fill; silty sand mixed with some clay (SM); A-2-4



B-5 34 350* 33* Silty sand (SM); A-2-4

B-5 39 4 9 Poorly graded sand with silt (SP-SM); A-3


B-5 59 9 25 Silty sand (SM); A-2-4

B-6 6½ 5 102 10 NP Poorly graded sand with silt (SP-SM); A-3

B-6 11½ 6 101 15 Silty sand (SM); A-2-4

B-6 16½ 4 106 8 Poorly graded sand with silt (SP-SM) A-3




SampleLocation


(%)

NaturalDry

Density(pcf)


Relationship

R-v

alue

@ 3

00 p

siEx

udat

ion

Pres

sure


t Pi

t/Bor

ing

No.

Dep

th (ft

)

Gra

vel (

%)

San

d (%

)

Silt

/Cla

y (%

)

LiquidLimit(%)

PlasticIndex(%) C

ohes

ion

(psf

)

Fric

tion

Ang

le (°)

MaximumDry

Density(pcf)


(%)


B-7 1½ 6 11 65 24 Fill; silty sand mixed with some clay (SM); A-2-4

B-7 6½ 5 3 80 17 NP Fill; silty sand mixed with some clay (SM); A-2-4


B-7 16½ 8 1 83 16 Fill; silty sand mixed with some clay (SM); A-2-4




B-7 44 14 56 Sandy lean clay (CL); A-4

B-7 54 5 108 10 Poorly graded sand with silt (SP-SM): A-3


B-7 69 10 108 16 Silty sand (SM); A-2-4




B-10 6½ 5 103 6 Poorly graded sand with silt (SP-SM); A-3




SampleLocation


(%)

NaturalDry

Density(pcf)


Relationship

R-v

alue

@ 3

00 p

siEx

udat

ion

Pres

sure


t Pi

t/Bor

ing

No.

Dep

th (ft

)

Gra

vel (

%)

San

d (%

)

Silt

/Cla

y (%

)

LiquidLimit(%)

PlasticIndex(%) C

ohes

ion

(psf

)

Fric

tion

Ang

le (°)

MaximumDry

Density(pcf)


(%)

B-10 9 3 99 13 Silty sand (SM); A-2-4

B-11 1½ 2 126 5 Poorly graded sand with silt and gravel (SP-SM);A-3

B-11 9-11 3 71 23 6 Poorly graded gravel with sand (GP); A-1-a

B-11 11½ 9 97 Silty sand (SM); A-2-4

B-11 14 17 111 69 Sandy fat clay (CH); A-7-5

B-12 3-5 4 19 76 5 Poorly graded sand with silt and Gravel (SP-SM);A-1-b

B-12 6½ 3 92 4 Poorly graded gravel with sand (GP)A-1-a

B-12 9 7 110 15 Silty sand (SM); A-2-4

B-12 24 5 101 4 Poorly graded sand (SP); A-3


B-13 4 2 4 Poorly graded gravel (GP); A-1-a


B-13 29 21 99 92 58 39 Fat clay (CH); A-7-5

* Test remolded at approximately 95% compaction near the optimum moisture content.** Test conducted at its exiting moisture content and density.

Page 5 of 5

APPLIED GEOTECHNICAL ENGINEERING CONSULTANTS, INC.

TABLE 2SUMMARY OF CHEMICAL LABORATORY TEST RESULTS


SAMPLE LOCATIONCHLORIDE

(PPM)pH RESISTIVITY

(OHM-CM)

WATER SOLUBLESULFATES

(PPM)

SAMPLE CLASSIFICATIONTEST PIT/

BORING #DEPTH(FEET)

TP-1 1-4 32 8.6 1,400 300 Fill; silty sand mixed with some clay (SM); A-2-4

TP-2 1-4 83 8.3 450 500 Fill; silty sand with gravel mixed with some clay (SM); A-2-4

TP-3 1-4 14 8.5 800 400 Fill; silty sand mixed with some clay (SM); A-2-4

B-2 10 300 Fill; silty sand mixed with some clay (SM); A-2-4

B-3 7½ 9.0 Fill; silty sand mixed with some clay (SM); A-2-4


B-4 1-7 11 8.2 1,070 Fill; silty sand mixed with some clay (SM); A-2-4

B-5 1-7 8.2 870 Fill; silty sand mixed with some clay (SM); A-2-4

B-5 14 35 500 Fill; silty sand mixed with some clay (SM); A-2-4


B-7 9 25 8.1 400 Fill; silty sand mixed with some clay (SM); A-2-4

B-9 1½ 161 1,200 Fill; silty sand mixed with some clay (SM); A-2-4