John Dunn_FINAL Geotech Rpt_20210927 REV.pdf

SUBMITTED TO:

HDR Engineering, Inc.

835 N Post Street Spokane, Washington 99201

BY:

Shannon & Wilson 1321 Bannock St., Suite 200 Denver, Colorado 80204

(303) 825-3800 www.shannonwilson.com

GEOTECHNICAL REPORT

NM FLAP TAO B007(1)

John Dunn Bridge

TAOS COUNTY, NEW MEXICO

September 2021 Shannon & Wilson No: 104002-001

NM FLAP TAO B007(1)

John Dunn Bridge

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CONTENTS

1 Introduction

2 Project and Site Description

3 Subsurface Explorations and Laboratory Testing

3.1 Field Investigation

3.2 Geotechnical Laboratory Testing

4 Regional Geology and Subsurface Conditions

4.1 Regional Geology

4.2 Site Soil and Bedrock Observations

4.3 Subsurface Conditions

4.4 Subsurface Variations

5 Geologic Hazard Evaluation

5.1 Seismic Hazards

5.2 Corrosion

6 Geotechnical Recommendations

6.1 Micropiles

6.2 Lateral Earth Pressures

7 Construction Considerations

7.1 Micropile Installation

7.2 Earthwork and Grading

7.2.1 Excavation

7.2.2 Fill Placement and Compaction

8 Closure

9 References

Exhibits Exhibit 4-1: Geologic map of the Arroyo Hondo Quadrangle Exhibit 4-2: Cliff exposures on the south side of the canyon Exhibit 4-3: Cliff exposures on the north side of the canyon Exhibit 4-4: Bouldery alluvium observed in the Arroyo Hondo Exhibit 5-1: Seismic Design Ground Motion Parameters Exhibit 6-1: Recommended Lateral Earth Pressure Design Parameters

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Figures Figure 1: Vicinity Map Figure 2: Site and Exploration Plan Figure 3: Recommended Surcharge Loading for Temporary and Permanent Walls

Appendices Appendix A: Suburface Explorations Appendix B: Laboratory Test Results Appendix C: Drilling Photographs Important Information

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ONYMS

1 INTRODUCTION

This report presents the results of our subsurface exploration program and provides geotechnical engineering recommendations for the proposed John Dunn Bridge Replacement Project (the Project) in Taos County, New Mexico (Figure 1). The report summarizes our subsurface explorations, laboratory testing and geotechnical engineering studies, and presents conclusions and recommendations for design of bridge foundations.

Our services were conducted in general accordance with our Task Order Agreement No.

022/1000100055503 with HDR Engineering, Inc. (HDR) dated October 12, 2020.

We understand this report will be used for design of the proposed replacement bridge project. This report should not be used for other purposes without Shannon & Wilson’s review. Our scope of services included:

The limitations of our approved scope, schedule, and budget described in our contract;

Our understanding of the Project and information provided by HDR;

Subsurface conditions observed in the borings at the time our explorations were completed; and

The results of testing performed on samples collected from the explorations.

The objective of our geotechnical studies was to provide recommendations and construction considerations, as presented herein, for the proposed bridge replacement. The authorized scope of services was based on this objective and this report should not be used for other purposes without Shannon & Wilson’s review. If a service is not specifically indicated in this report, do not assume that it was performed.

2 PROJECT AND SITE DESCRIPTION

The Project is located in Taos County, New Mexico, near Arroyo Hondo. The proposed bridge replacement is for a northwest-southeast oriented, one-lane, Rio Hondo Bridge crossing the Rio Hondo along County Road B-007 (Figure 2). For purposes of this report the bridge is considered north-south oriented. The proposed replacement bridge is east of the existing John Dunn Bridge, which crosses the Rio Grande. The bridge to be replaced is approximately 40 feet long and 19 feet wide. As-builts for the existing bridge are not available; however, HDR indicated that the structure appears to be founded on masonry shallow foundations. The proposed replacement bridge will consist of an approximately 60-

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104002-001 September 2021 foot-long single-span structure founded on micropiles. Short abutment and wing walls may be required as part of the project.

3 SUBSURFACE EXPLORATIONS AND LABORATORY

TESTING

3.1 Field Investigation

Shannon & Wilson conducted a field exploration program on October 20 and 21, 2020, to explore subsurface conditions at the proposed replacement bridge location. The subsurface exploration program consisted of drilling and sampling two borings designated SW-01 and SW-02, as shown in Figure 2.

Appendix A presents a discussion of the drilling and sampling procedures used to complete the borings. Appendix A also presents the individual exploration logs and an explanation of the symbols and terminology used. Photographs of the drilling locations are included in Appendix C.

3.2 Geotechnical Laboratory Testing

Geotechnical laboratory tests were completed on selected samples retrieved from the borings to estimate index and engineering properties. Index tests included natural water content, grain size analysis, and Atterberg limits. Engineering properties tests included unconfined compressive strength test and corrosion testing. Laboratory test results and a discussion of the testing procedures are included in Appendix B. The natural water content, fines content, and Atterberg limits are also shown on the individual boring logs included in Appendix A.

4 REGIONAL GEOLOGY AND SUBSURFACE

CONDITIONS

4.1 Regional Geology

The Geologic Map of the Arroyo Hondo Quadrangle, Taos County, New Mexico (Kelson and Bauer, 2006) indicates that the surficial geology at the site consists of Servilleta Formation basalt flows that were emplaced during the Pliocene Epoch (age dated to approximately 3.1 to 4.8 million years ago). This basalt forms the columnar-jointed cliffs in the Rio Grande Gorge with individual basalt flows reported to be up to about 50 feet thick.

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Individual basalt flows are present in sequences of up to ten flows and are locally separated by interflow sedimentary units ranging in thickness from about 15 feet to more than 500 feet in some locations. Refer to Exhibit 4-1 for a regional geology map indicating that the project area is mapped as Servilleta Formation Basalt.

LEGEND: Qal = stream channel and valley-floor alluvium, and active floodplains; Qfy = young alluvial-fan and stream terrace deposits;

Qt6/Qt5/Qt4/Qt3/Qt2 = stream terrace deposits; Qt2rg/Qt1rg = stream terrace deposits flanking Rio Grande; QTrg = stream gravel deposited by ancestral Rio Grande; QTg = old alluvium; QTbh = Blueberry Hill deposit; Tb = Servilleta Formation, basalt.

Exhibit 4-1: Geologic map of the Arroyo Hondo Quadrangle. From Kelson and Bauer, 2006.

Project Location

QTg

QTbh

QTrg

Qt6

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4.2 Site Soil and Bedrock Observations

While onsite, we made generalized visual observations of soil and bedrock exposures adjacent to the roadway on the south abutment. This effort did not include performing detailed rock mass structure mapping.

Along the south abutment, we noted exposures of Servilleta Formation Basalt forming the lowermost, approximately 20-foot-high, 1V:1H (vertical to horizontal) slope adjacent to the roadway (see Exhibit 4-2). The cliff exposures in this lower slope consisted of strong to very strong (estimated unconfined compressive strength ranging from about 7,200 to 36,000 pounds per square inch [psi]), dark brown basalt. We noted that this basalt exposure was cut by both an approximately horizontal discontinuity set and apparently randomly oriented joints. We observed that individual fracture traces adjacent to the road were very closely to widely spaced (discontinuity spacing of about 2.5 inches to 6 feet), forming a fractured, interlocking rock mass with individual block sizes with maximum dimensions commonly on the order of about 4 inches to 3 feet. We observed the joints to have variable degrees of dilation, with some joints displaying dilation on the order of about one inch.

Exhibit 4-2: Cliff exposures on the south side of the canyon. View to the southwest.

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Higher in the basalt slope, we noted a nearly vertical, approximately 20-foot-high horizon with prominent, high-angle, undulating columnar joints with spacing on the order of about 5 to 10 feet. We did not observe cliffs with columnar rock mass at the road elevation on either side of the bridge.

Exhibit 4-3: Cliff exposures on the north side of the canyon. View to the northwest.

To the east of the basalt exposure along the south abutment and on the slopes above the east abutment, we observed colluvium slopes extending through gaps in the lower canyon basalt cliffs to the canyon rim approximately 350 feet above. Colluvium slopes were observed to stand at approximate slope angles on the order of 1V:2H with deposits of silty or clayey sand with gravel, cobbles, and boulders on the surface. Higher on the south slopes, aerial photos indicate talus-like deposits with individual boulders up to approximately 10 feet in diameter. From the roadway, we observed these colluvium deposits to contain angular basalt boulders up to about 6 feet in maximum dimension.

We observed bouldery alluvium deposits in Arroyo Hondo, with individual boulders primarily consisting of basalt lithology. The alluvial deposits included boulders up to about 3 feet in diameter.

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Exhibit 4-4: Bouldery alluvium observed in the Arroyo Hondo. View to the northeast.

4.3 Subsurface Conditions

Boring SW-01, completed approximately 25 feet from the proposed north bridge abutment location, encountered approximately 2 feet of aggregate surfacing overlying overburden materials consisting of very loose to loose sand with varying percentages of silt and clay and an approximately 1-foot thick sandy clay layer. At a depth of 14.6 feet below ground surface (bgs), basalt was encountered to the termination depth of the boring at approximately 45.0 feet.

Subsurface conditions at the southern bridge abutment in boring SW-02, which was completed approximately 12 feet from the proposed abutment, consisted of approximately 3 feet of aggregate surfacing. Below the aggregate surfacing very loose, clayey sand with gravel was encountered to a depth of approximately 7 feet. Basalt bedrock with multiple hard clay seams ranging from 1 to 13 inches in thickness was then encountered, and extended to the bottom of the boring, which terminated at a depth of 25 feet. The deposits encountered below 7 feet in boring SW-02 could potentially be interpreted as a colluvium deposit consisting of basalt cobbles and boulders with a hard, sandy clay infilling between

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104002-001 September 2021 clasts. Regardless of the uncertainty in the characterization of the geologic origin of this material, the design and construction considerations presented herein are applicable for both interpretations.

During drilling, groundwater was encountered in borings SW-01 and SW-02 at a depth of 5 feet bgs, which approximately corresponded to the water surface elevation of Rio Hondo.

The groundwater level at the time of drilling is noted on each boring log included in Appendix A. Groundwater fluctuations are likely and will depend on seasonal variations, local precipitation and runoff, and other factors, but will primarily be influenced by water levels in the Rio Hondo and flood events.

4.4 Subsurface Variations

The explorations were performed to evaluate subsurface conditions at the Project site. The borings were completed as close as possible to the proposed abutment locations while keeping the roadway open during the drilling operations. Our observations are specific to the locations, depths, and times noted on the logs and may not be applicable to all areas of the site. No amount of explorations or testing can precisely predict the characteristics, quality, or distribution of subsurface and site conditions. Potential variation includes, but is not limited to:

The conditions between explorations may be different.

The passage of time or intervening causes (natural and manmade) may result in changes to site and subsurface conditions.

If conditions different from those described herein are encountered during construction, we should review our description of the subsurface conditions and reconsider our conclusions and recommendations.

5 GEOLOGIC HAZARD EVALUATION

5.1 Seismic Hazards

The Project is within the San Luis Basin of the Rio Grande rift zone. Based on a recent geologic map by the U.S. Geological Survey (USGS), the nearest fault to the Project is one of the Los Cordovas Faults, approximately 1,450 feet to the northwest (Kelson and Jochems, 2015). These faults have an estimated slip rate of less than 0.2 millimeters per year.

Therefore, in our opinion, the potential for ground surface fault rupture is low.

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Liquefaction may occur in loose, saturated, cohesionless soils when subjected to earthquake ground shaking. Based on the subsurface conditions encountered at the site and the relatively low peak ground acceleration (PGA) for this area, it is our opinion that the risk of liquefaction is low.

Using the American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifications (AASHTO, 2020) criteria, and based on subsurface conditions encountered in our borings at the proposed bridge (assuming that similar conditions are present from the maximum depth of our boring to a depth of 100 feet), we recommend Site Class D for the proposed bridge.

Ground motion parameters were determined for the Project site using the USGS AASHTO 2009 Web Service Documentation Web Application (USGS, 2009) and procedures recommended by AASHTO (2020). Exhibit 5-1 presents recommended seismic design ground motion parameters.

Exhibit 5-1: Seismic Design Ground Motion Parameters

Design Parameter Value

Peak Ground Acceleration 1 (PGAB) 0.088 g

Site Class D

Short-period Spectral Acceleration, SS 0.206 g

Long-period Spectral Acceleration, S1 0.066 g

Site Factor, FPGA 1.6

Site Factor, Fa 1.6

Site Factor, Fv 2.4

Peak Design Spectral Acceleration, AS 0.141 g

Short-period Design Spectral Acceleration, SDS 0.329 g

Long-period Design Spectral Acceleration, SD1 0.157 g

T0 0.10 sec.

TS 0.48 sec.

Seismic Zone 2

NOTES:

PGAB = peak ground acceleration for a site underlain by Site Class B soil (soft rock) Based on AASHTO 2020 Guide Specifications.

g = gravitational acceleration; sec. = seconds

5.2 Corrosion

The soil encountered at the project site can be corrosive to substructure elements. To assist in estimating the corrosion potential at the site, selected samples were tested for pH, Geotechnical Report

104002-001 September 2021 resistivity, water soluble sulfates, and chlorides. The results are presented in Table B-1 in Appendix B.

The resistivity measured in the samples ranged from 1,103 to 5,255 ohm-centimeters. Based on correlations developed by Roberge (2012), these values suggest a highly corrosive to corrosive subsurface conditions for metal in contact with subsurface materials across the site.

The concentration of water-soluble sulfates measured in the samples was less than 0.001 to 0.003% by weight. Based on classifications as defined by ACI-318-19 (ACI, 2019), these test results suggest an exposure class S0 on concrete exposed to site soils.

The test results and the above discussion are provided to assist the designer in the selection of project materials, concrete type, or other features with respect to corrosion. As appropriate, the designer should consider protective measures, such as coatings, upsizing for section loss, or using alternative materials to reduce the corrosion potential.

6 GEOTECHNICAL RECOMMENDATIONS

As discussed in Section 2.0, we understand the proposed bridge will consist of a single-span structure founded on micropiles. The borings indicate that bedrock was encountered at a depth of approximately 14.6 feet and 9.3 feet bgs in borings SW-01 and SW-02. In our opinion, micropiles are a cost-effective and appropriate foundation system for the bridge based on the subsurface conditions encountered at the site.

6.1 Micropiles

The following summarizes our recommendations for the geotechnical design of micropiles to support the abutments. Structural design of the micropiles will be completed by HDR.

Permanent casing should extend from the pile cap to at least the basalt bedrock contact.

The axial compression of the micropiles should be based on a nominal grout bond strength of 10 kips per square foot (ksf) in uncased basalt. The contractor should be responsible for determining the appropriate construction method to achieve this bond strength.

The minimum bond length (below the bottom of casing) should be 10 feet.

Micropiles should be spaced a minimum of 3 diameters center-to-center.

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In accordance with AASHTO, we recommend a resistance factor of 0.70 for nominal bond strength in compression and uplift, assuming sacrificial load testing is completed as discussed below.

Axial resistance should be ignored within the cased section of micropiles.

Corrosion protection is required for the reinforcing center bar according to the FHWA Micropile Design and Construction Manual (Sabatini and others, 2005). The corrosion protection should include grout cover. In addition, because of the permanent nature of the micropiles, we recommend one of the following: epoxy coating, galvanization, or encapsulation.

Corrosion protection for permanent casing should include a sacrificial steel section loss of 0.063 inches in accordance with the FHWA Micropile Design and Construction Manual (Sabatini and others, 2005).

We understand that HDR will account for lateral loads by using batter piles

Total settlement of individual micropiles is anticipated to be less than ½ inch.

Differential settlement between adjacent micropiles would be expected to be about 50 to 75% of this value. This assumes the micropiles are constructed using good installation techniques and equipment based on criteria described in FHWA Micropile Design and Construction Manual (Sabatini and others, 2005).

To verify the assumed bond strengths used for design, a sacrificial (verification) load test should be completed at the south abutment in accordance with the FHWA Micropile Design and Construction Manual (Sabatini and others, 2005). The verification load test can be conducted in either tension or compression. The micropile used for the verification test should be loaded to at least 2.0 times the design load of the installed micropile.

Production proof tests should be completed at each substructure unit. The micropile used for proof testing should be loaded to 1.6 times the design load of the installed micropile. Provided the proof tests meet the test requirements, the micropiles may be incorporated as production micropiles.

If the required capacities are not demonstrated in the verification test, longer micropiles may be required depending on the installation means and methods of the contractor.

As described in Section 4.3, there is potential for the material described as bedrock in boring SW-02 to be colluvium consisting of cobbles and boulders with clay infilling. To the extent that this material in boring SW-02 could be colluvium, the recommendations provided herein consider the uncertainty in the characterization of this material and would still be applicable.

The bond strengths provided herein used the lowest strength rock tested onsite and accounted for clay seams by assuming zero adhesion for the clay seams as observed in

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104002-001 September 2021 boring SW-02. The value was further reduced by a factor of approximately 2.5 to account for the potential subsurface variability encountered within the basalt bedrock. .

6.2 Lateral Earth Pressures

The lateral earth pressures on abutment and wing walls depend on many factors, including surcharge loads, the soil type, drainage provisions, and whether or not the top of the wall can yield or deflect laterally/rotate during and after excavation. Where walls are free to deflect, they can be designed for the active condition. Where a deflection greater than

0.001 times the height of the wall (0.001H) cannot occur, walls should be designed for at-rest conditions. Active and at-rest earth pressures provided in Exhibit 6-1 assume the walls are backfilled with properly compacted onsite clayey sands or Structural Backfill in accordance with FP-14 Section 704.04 in a 1V:1H zone extending upward from the base of the wall from a point 1.5 feet behind the wall.

Exhibit 6-1: Recommended Lateral Earth Pressure Design Parameters

Design Parameter

Design Value

On-site Clayey Sand Fill

Structural Backfill - FP-14 Section 704.04

Total Unit Weight (pcf) 125 135

Effective Friction Angle (degrees) 28 34

Cohesion (psf) 0 0

Active Earth Pressure Coefficient, KA 0.36 0.28

Equivalent Fluid Density for Active Conditions (pcf) 45 40

At-Rest Earth Pressure Coefficient, KO 0.53 0.44

Equivalent Fluid Density for At-Rest Conditions (pcf) 65 60

NOTES:

Does not include water pressure, see below.

pcf = pounds per cubic foot; psf = pounds per square foot

Surcharge loads from motor vehicles/traffic and construction equipment will induce additional lateral loads on walls. The pressures provided in Exhibit 6-1 do not account for surcharge loads. Lateral loads due to various types of surcharges may be calculated by multiplying the surcharge by the active or at-rest earth pressure coefficient (KA or KO). The earth pressure coefficients are also shown in Exhibit 6-1. Surcharge loads should be applied as recommended on Figure 3.

The parameters provided in Exhibit 6-1 assume a free-draining backfill condition. It will be important to control surface water and to provide drainage measures that reduce the

Geotechnical Report

104002-001 September 2021 potential for water to accumulate behind walls, particularly considering the proximity of walls to the Rio Hondo.

Surface water behind the wall should not be allowed to discharge directly into the wall backfill materials. In addition, water should not be allowed to discharge or pond around retaining structures. We recommend sloping the ground surface in front of walls a minimum of 5% away from the wall face for a minimum horizontal distance of 10 feet measured from the face of the wall (or until a paved surface is encountered, whichever is less).

In general, materials with greater than about 3% fines content are not considered free draining. Assuming on-site clayey sand fill or structural backfill is used, the backfill will not be free draining, and a rapid drawdown condition could occur following flood events, i.e., water could be trapped in the backfill after flood waters recede. This condition could be addressed by designing the wall for appropriate water pressures or by including internal drainage features to reduce the potential for water to accumulate in the backfill.

Appropriate drainage features could include:

Placement of a 12-inch thick drainage layer on the back face of the wall, with a discharge system (e.g., weep holes or a perforated collector pipe at the base of the drainage layer, daylighting to a suitable discharge point).

Installation of geocomposite drainage boards on the back face of the wall, with a suitable discharge system (e.g., weep holes or a perforated collector pipe, daylighting to a suitable discharge point)

Limiting the fines content of the wall backfill to 3%.

7 CONSTRUCTION CONSIDERATIONS

The applicability of the design parameters in Section 6.0 is contingent on good construction practice. Poor construction techniques may alter conditions from those upon which our recommendations are based, and therefore result in poor performance. Our analyses assume that this project will be constructed according to FP-14 U.S. Customary Units (FHWA, 2014) standards. The following sections provide additional construction considerations for this project.

7.1 Micropile Installation

Micropiles should be constructed in accordance with our recommendations, the guidelines in the Section 567 of FP-14 (FHWA, 2014), and the FHWA Reference Manual, “Micropile

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Design and Construction” (Sabatini and others, 2005). Micropile contractors should be prepared to install battered micropile installation through the clay seams encountered in boring SW-02, as well as the potential for grout loss in the basalt. The drilling and grouting process should be relatively continuous with minimal stoppage of work between the completion of drilling and cleaning the hole and placement of grout after setting the reinforcing bar, and under no circumstances after the day of drilling. We anticipate that the micropiles will be constructed below the groundwater and that the grout should be placed using a tremie tube.

We recommend that micropile contractors who participate on this project be required to demonstrate that they have suitable equipment for this project and adequate experience in construction with similar subsurface conditions.

7.2 Earthwork and Grading

Earthwork, including site preparation, placement of fill, and subgrade preparation, should conform to the requirements provided in Division 200 of the Standard Specifications for Construction of Roads and Bridges on Federal Highway Projects, FP-14 (FHWA, 2014).

7.2.1 Excavation

The overburden and surficial soils may contain boulders as discussed in Section 4.2, and the contractor will need to provide a means to excavate such boulders.

7.2.2 Fill Placement and Compaction

Subgrade material and fill should be placed in accordance with FP-14 Section 204.11.

8 CLOSURE

This report has been prepared for the exclusive use of HDR and Central Federal Lands Highway Division for the purpose of providing geotechnical recommendations for the John Dunn Bridge project. This geotechnical design report should not be used without our approval if any of the following occurs:

Assumptions stated in this report have changed.

Project details change or new information becomes available such that our analysis and recommendations may be affected.

A substantial period of time has passed since the date of this report.

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If any of these occur, we should be retained to review the applicability of our analyses and recommendations.

Within the limitations of scope, schedule and budget, the analyses, conclusions and recommendations presented in this report were prepared in accordance with generally accepted professional geotechnical and geological principles and practice in this area at the time this report was prepared. We make no other warranty, either express or implied.

Shannon & Wilson has prepared “Important Information about Your Geotechnical Report,” to assist you and others in understanding the use and limitations of our reports.

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9 REFERENCES

American Concrete Institute (ACI), 2019, Building code requirements for structural concrete and commentary, Farmington Hills, Mich., ACI 318-19.

American Association of State Highway and Transportation Officials (AASHTO), 2020, AASHTO LRFD bridge design specifications, Customary U.S. units, 9th edition:

Washington, D.C., American Association of State Highway and Transportation Officials.

Kelson, K., and Bauer, P., 2006, Geologic Map of the Arroyo Hondo Quadrangle, Taos County, New Mexico: New Mexico Bureau of Geology and Mineral Resources Open-File Geologic Map OF-GM 116, scale 1:24,000.

Kelson, K., and Jochems, A., compilers, 2015, Fault number 2022, Los Cordovas faults, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, https://earthquakes.usgs.gov/hazards/qfaults, accessed 10/29/2020.

Roberge, P.R., 2012, Handbook of corrosion engineering, Second Edition: McGraw-Hill, New York, New York.

Sabatini and others, 2005, Federal Highway Administration (FHWA) and National Highway Institute (NHI) Course No. 1320789, Micropile Design and Construction, Publication No. FHWA NHI-05-039, December.

U.S. Department of Transportation (USDOT), Federal Highway Administration (FHWA), 2014, Federal standard specifications for construction of roads and bridges on Federal Highway projects, FP-14 English Units: U.S. Department of Transportation and Federal Highway Administration, available from http://flh.fhwa.dot.gov/resources/pse/specs/.

U.S. Geological Survey (USGS) AASHTO 2009 Web Service Documentation Web Application (USGS, 2009). Available from:

https://earthquake.usgs.gov/ws/designmaps/

VICINITY MAP

FIG. 1SHANNON & WILSON, INC.

Approximate Scale in Miles

0 0.25 0.5

Fi le na m e:

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L og in : A

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Map adapted from aerial imagery provided by Google Earth Pro, reproduced by permission granted by Google Earth ™ Mapping Service.

NOTE

MT

104002-001

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

PROJECT

LOCATION

Project Location

New Mexico Las Cruces

Tucumcari

Socorro

Albuquerque

Santa Fe

Raton

Gallup

Arroyo Hondo

B-007

Ri o

G ra nd e

Rio Hondo

104002-001

SITE AND EXPLORATION PLAN

SHANNON & WILSON, INC.

Fi le

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1-

-2

A ut ho r:

AE

G

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

MT

SW-01

LEGEND

Boring Designation and Approximate Location

NOTES

1. Map adapted from aerial imagery provided by Google Earth

Pro, reproduced by permission granted by Google Earth ™ Mapping Service.

FIG. 2

0 100 200

Approximate Scale in Feet

B-007

John Dunn Bridge

Rio Grande

Proposed Bridge Replacement

SW-01

SW-02

Rio Hondo

For m ≤ 0.4: H = 0.28 (psf) (see Note 3)

Fi le

: I :\E

F\ D

E N

\1

0s

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-T yp

S ur ch ar ge .d e:

2-

-2

A ut ho r:

jc g

W al l

PLAN VIEW

2.0

1.5

D ep th F ac to r, Z/

B

1.0

0.0

0.5

W al l

Z

Wall Line

UNIFORM SURCHARGE

EARTH BERM

(see Note 4)

Note:

H z=nH

Bottom of Excavation x = mH

Point Load in Pounds

H (psf)

ELEVATION VIEW

x = mH

H

Bottom of Excavation

W al l z=nH

H (psf)

Line Load in Pounds/Foot

B) LATERAL PRESSURE DUE TO LINE LOAD

i.e. NARROW CONTINUOUS FOOTING

PARALLEL TO WALL

C) LATERAL PRESSURE DUE TO STRIP LOAD

W al l

W al l

W al l

A) LATERAL PRESSURE DUE TO POINT LOAD

i.e. SMALL ISOLATED FOOTING OR WHEEL LOAD

D) LATERAL PRESSURE DUE TO EARTH BERM

OR UNIFORM SURCHARGE

Bottom of Excavation

Bottom of Excavation

E) LATERAL PRESSURE DUE

TO ADJACENT FOOTING

(see Notes 5 and 6)

0 0.5 1.0

L

B

NOTES

Figures are not drawn to scale.

Applicable surcharge pressures should be added to appropriate temporary and permanent wall lateral earth and water pressure.

If point or line loads are close to the back of the wall such that m 0.4, it may be more appropriate to model the actual load distribution (i.e., Detail E) or use more rigorous analysis methods.

See text for recommended K values.

The stress is estimated on the back of the wall at the center of the length, L, of loading.

The estimated stress is based on a Poisson's ratio of 0.5.

W al l

Bearing Pressure q (psf)

1.

2.

3.

4.

5.

6.

Ip, Influence Factor

H = 2(Ip) qs

Lateral Footing Pressure on Wall

(derived from NAVFAC DM 7.02, 1986; and Sandhu, Earth Pressure on Walls Due to Surcharge, 1974)

(derived from Poulos and Davis, Elastic Solutions for Soil and Rock Mechanics, 1974; and Terzaghi and

Peck, Soil Mechanics in Engineering Practice, 1967)

(NAVFAC DM 7.02, 1986)

(derived from Fang, Foundation Engineering Handbook, 1991)

(NAVFAC DM 7.2, 1986)

Point Load in Pounds

= Unit Weight of Earth Berm

Bearing Pressure

Earth Berm

H = Lateral Pressure in radians

ELEVATION VIEW

(see Note 3) (see Note 3) qs

L 2B

Qp

H2 n2

(0.16 + n2)3

For m > 0.4: H = 1.77 (psf) Qp

H2 m2n2

(m2 + n2)3

Qp

H

'H = H cos2 (1.1 ) (psf)

'H 'H

For m ≤ 0.4: H = 0.20 (psf) (see Note 3) Ql

H n

(0.16 + n2)2

For m > 0.4: H = 1.28 (psf) Ql

H m2n

(m2 + n2)2

QlQp

≤ 33° Hs ≤ 15 Feet

(K)( )(Hs) 2H

Hs

H = (K)qs (see Note 4) qs (psf)

H = ( - sin cos2 ) (psf)2q

L

= 0.25 = 0.5

= 1

H

L 2B

L 2B

L 2B

RECOMMENDED SURCHARGE

LOADING FOR TEMPORARY AND

PERMANENT WALLS

FIG.

104002-001 202

NM FLAP TAO B007(1)

Taos County, New Mexico

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Appendix A: Subsurface Ex plorations

Appendix A

Subsurface Explorations

CONTENTS

A.1 Introduction ........................................................................................................................... A-1

A.2 Explorations ........................................................................................................................... A-1

A.2.1 Soil and Rock Classification System ...................................................................... A-1

A.2.2 Standard Penetration Test (SPT) ............................................................................ A-1

A.2.3 Rock Core Sampling ................................................................................................ A-2

Figures Figure A-1: Soil Description and Log Key Figure A-2: Rock Classification and Log Key Figure A-3 and A-4: Log of Borings SW-01 and SW-02 Figure A-5 and A-6: Rock Core Photographs: Boring SW-01 and SW-02

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A.1 INTRODUCTION

Shannon & Wilson’s field exploration program was conducted on October 20 and 21, 2020, and consisted of drilling two borings, designated SW-01 and SW-02 at the locations shown in Figure 2. Photographs of boring locations are provided in Appendix C. The methods used to conduct the field exploration program are described below.

A.2 EXPLORATIONS

The borings were coordinated (including subcontractor coordination and utility locates) and observed by Shannon & Wilson. Individual boring logs are presented in Figures A-3 and A-

4. These exploration logs represent our interpretation of the contents of the field logs and select results of laboratory testing. The borings were drilled by Vine Laboratories, Inc. of Commerce City, Colorado (under subcontract to Shannon & Wilson) using an ATV mounted CME-750X drill rig. The borings were advanced to depths ranging from 25.2 to

45.0 feet using 6-inch outer diameter hollow-stem-auger drilling techniques and NQ2 rock coring methods. Where groundwater was encountered, our field representative measured the approximate depth to groundwater using an electronic water level indicator. On completion of drilling, the borings were backfilled with cuttings and spread to approximately match the existing grade.

A.2.1 Soil and Rock Classification System

During exploration, our representative collected samples and prepared field logs of the explorations. Soil classification for this project was based on ASTM International (ASTM) Designation: D2487, Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System), and ASTM Designation: D2488, Standard Practice for Description and Identification of Soils (Visual-Manual Procedure). The Unified Soil Classification System is summarized in Figure A-1. The Shannon & Wilson representative classified rock samples in general accordance with the International Society of Rock Mechanics (ISRM) classification method. According to this system, rocks are classified based on the stratigraphic structure, rock strength, degree of weathering, and other properties. The rock classification system is summarized in Figure A-2.

A.2.2 Standard Penetration Test (SPT)

Disturbed samples were obtained in the borings in general accordance with the Standard Penetration Test (SPT) (ASTM Designation: D1586). The SPT consists of driving a 2-inch

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outside diameter, 1.375-inch inside diameter split-spoon sampler a distance of 18 inches with a 140-pound hammer free-falling a distance of 30 inches. An automatic hammer system was used to advance the samplers. The energy transfer ratio (ETR) for the hammer on the CME-750X ATV mounted drill rig was 97% based on a July 2019 report provided by Vine Laboratories. During sampling, the Shannon & Wilson field representative recorded the number of blows for each 6-inch increment of penetration and summed the blow counts for the last two 6-inch increments. This sum is recorded as the penetration resistance number, or N-value. If high penetration resistance prevented driving the total length of the sampler, the Shannon & Wilson field representative recorded the partial penetration depth and blow count. The N-values provide a means for evaluating the relative density or compactness of cohesionless (granular) soils and consistency or stiffness of cohesive (fine-grained) soils (see Figure A-1). The raw N-values are shown on the individual boring logs.

Representative portions of the split-spoon sample obtained in conjunction with the SPT were placed in a screw-top plastic jar and transported to our laboratory.

A.2.3 Rock Core Sampling

Rock samples were collected using NQ2 double tube wireline coring methods (1.875-inch-nominal-diameter rock core). During coring, cuttings were removed from the borehole by circulating water down through the drill rods and back up the annulus of the boring. Core runs were 5 feet in length, except for the first core run, which reamed out disturbed material at the bottom of the borehole.

Percent recovery and rock quality designation (RQD) values are shown on the boring log where coring was completed. Percent recovery is the ratio of the length of recovered core to the total length of the core run. RQD is the ratio, expressed as a percent, of the sum of the length of intact core pieces greater than 4 inches long in a run to the total length of the core run. Following drilling, the core was logged by the Shannon & Wilson field representative, then stored in cardboard core boxes and transported to the Shannon & Wilson laboratory.

Photographs of cores are presented in Figures A-5 and A-6.

FIG. A-3

Sheet 1 of 3

Sheet 2 of 3

Sheet 3 of 3

FIG. A-4

Sheet 1 of 2

FIG. A-4

Sheet 2 of 2

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 1 17.5’ – 20.0’

FIG. A-5

ROCK CORE PHOTOGRAPHS

BORING SW-01

Sheet 1 of 6

FIG

. A

-5 Sheet 1 of 6

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 2 20.0’ – 25.0’

FIG. A-5

ROCK CORE PHOTOGRAPHS

BORING SW-01

Sheet 2 of 6

FIG

. A

-5 Sheet 2 of 6

Photo Match Line

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 3 25.0’ – 30.0’

FIG. A-5

ROCK CORE PHOTOGRAPHS

BORING SW-01

Sheet 3 of 6

FIG

. A

-5 Sheet 3 of 6

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 4 30.0’ – 35.0’

FIG. A-5

ROCK CORE PHOTOGRAPHS

BORING SW-01

Sheet 4 of 6

FIG

. A

-5 Sheet 4 of 6

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 5 35.0’ – 40.0’

FIG. A-5

ROCK CORE PHOTOGRAPHS

BORING SW-01

Sheet 5 of 6

FIG

. A

-5 Sheet 5 of 6

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 6 40.0’ – 45.0’

FIG. A-5

ROCK CORE PHOTOGRAPHS

BORING SW-01

Sheet 6 of 6

FIG

. A

-5 Sheet 6 of 6

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 1 9.3’ – 10.2’

FIG. A-6

ROCK CORE PHOTOGRAPHS

BORING SW-02

Sheet 1 of 4

FIG

. A

-6 Sheet 1 of 4

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 2 10.2’ – 15.2’

FIG. A-6

ROCK CORE PHOTOGRAPHS

BORING SW-02

Sheet 2 of 4

FIG

. A

-6 Sheet 2 of 4

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 3 15.2’ – 20.2’

FIG. A-6

ROCK CORE PHOTOGRAPHS

BORING SW-02

Sheet 3 of 4

FIG

. A

-6 Sheet 3 of 4

John Dunn Bridge

Taos County, New Mexico

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Run 4 20.2’ – 25.2’

FIG. A-6

ROCK CORE PHOTOGRAPHS

BORING SW-02

Sheet 4 of 4

FIG

. A

-6 Sheet 4 of 4

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Appendix B: Laboratory Test Results

Appendix B

Laboratory Test Results

CONTENTS

B.1 Introduction ............................................................................................................................B-1

B.2 Geotechnical Index Tests.......................................................................................................B-1

B.2.1 Water Content............................................................................................................B-1

B.2.2 Grain Size Analysis ...................................................................................................B-1

B.2.3 Atterberg Limits ........................................................................................................B-1

B.3 Geotechnical Engineering Property Tests...........................................................................B-2

B.3.1 Corrosion....................................................................................................................B-2

B.3.2 Uniaxial Compressive Strength ..............................................................................B-2

Table Table B-1: Summary of Laboratory Test Results

Figures Figure B-1: Grain Size Distribution Figure B-2: Plasticity Chart Figure B-3 through B-5: Uniaxial Compressive Strength of Intact Rock Core Specimens:

Boring SW-01, Samples R-5 and R-6;

Boring SW-02, Sample R-4

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B.1 INTRODUCTION

Laboratory tests were completed on soil samples retrieved from the borings in general accordance with American Association of State Highway and Transportation Officials (AASHTO) test methods and ASTM International (ASTM) test methods. The laboratory testing program was performed to classify the materials into similar geologic groups and provide data that can be used for design of the project. The geotechnical laboratory testing was performed at our laboratory in Denver, Colorado and Colorado Analytical Laboratories, Inc. of Brighton, Colorado. A summary of the laboratory test results is presented in Table B-1. The following sections describe the laboratory testing procedures.

B.2 GEOTECHNICAL INDEX TESTS

B.2.1 Water Content

Water content was determined for selected samples in general accordance with AASHTO T265, Laboratory Determination of Moisture Content of Soils. To perform this test, a sample was weighed before and after oven-drying, and the water content was calculated. Water content determinations are shown graphically on the boring logs and are also summarized in Table B-1.

B.2.2 Grain Size Analysis

The grain size distribution of selected samples was determined in general accordance with AASHTO T88, Standard Method of Test for Particle Size Analysis of Soils. Results of these analyses are presented as grain size distribution curves on Figure B-1 and summarized in Table B-1. Selected samples were also tested for the percentage of material passing the No.

200 sieve in general accordance with AASHTO T11, Standard Method of Test for Materials Finer than 75-μm (No. 200) Sieve in Mineral Aggregates by Washing. The percent fines (silt-and clay-sized particles passing the No. 200 sieve) are shown graphically on the boring logs in Appendix A and are also summarized in Table B-1.

B.2.3 Atterberg Limits

Soil plasticity was determined by performing Atterberg limits tests on selected fine-grained samples. The tests were completed in general accordance with AASHTO T89, Standard Test Method for Determining the Liquid Limit of Soils and AASHTO T90, Standard Test Method for Determining the Plastic Limit and Plasticity Index of Soils. The Atterberg limits include liquid limit (LL), plastic limit (PL), and plasticity index (PI equals LL minus PL) and are

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generally used to assist in classification of soils, to indicate soil consistency (when compared to natural water content), and to provide correlation to soil properties. The results of the Atterberg limits tests are plotted on a plasticity chart on Figure B-2, shown graphically on the boring logs in Appendix A, and summarized in Table B-1.

B.3 GEOTECHNICAL ENGINEERING PROPERTY TESTS

B.3.1 Corrosion

Corrosion testing of select samples was performed for pH, resistivity, sulfate content, and chloride content by Colorado Analytical Laboratories, Inc. Testing for pH was completed in general accordance with AASHTO T289-91, Standard Test Method for Measuring pH of Soil for Use in Corrosion Testing. Resistivity testing was completed in accordance with AASHTO T288-91, Standard Method of Test for Determining Minimum Laboratory Soil Resistivity. Sulfate content testing was completed in general accordance with AASHTO T290-91, Standard Method of Test for Determining Water-Soluble Sulfate Ion Content in Soil. Chloride content testing was completed in general accordance with AASHTO T291-91, Standard Method of Test for Determining Water-Soluble Chloride Ion Content in Soil. Test results for sulfate and chloride content are given in units of percent by weight. The test results are summarized in Table B-1.

B.3.2 Uniaxial Compressive Strength

Unconfined compressive strength testing on rock samples was completed in general accordance with ASTM D7012, Standard Test Method for Compressive Strength of Intact Rock Core Specimens. The results of the unconfined compressive strength tests are included on Figures B-3 through B-5 and are also summarized in Table B-1.

Geotechnical Report

Table B-1 - Summary of Laboratory Test Results pH Boring Sample Top Bottom

S-1A 1 2.3 6.5 S-1B 2.3 2.5 17.7 S-3A 6.5 7.6 8.4 5,255 0.003 0.0006

S-4 9 10.5 SM 21 59 20 NV NP NP

R-5 35.1 35.4 1.3 141.1 8,110 R-6 42.7 43 1.5 166.1 22,260 S-1 1 2.5 8.2

S-2 4 5.5 SC 17.8 26 31 43 34 15 19

R-3 18 18.4 CL 75 44 19 25 8.4 1,103 <0.001 0.0002

R-4 22.5 22.8 0.8 126.7 4,500

NOTES:

1. Refer to Appendix A, Figure A-1 for definitions.

2. Gravel defined as particles larger than the No. 4 sieve size. Sand as particles between the No. 4 and No. 200 sieve size. Fines as particles passing the No. 200 sieve size.

3. NP = Non Plastic; NV = No Value

GRAIN-SIZE

ANALYSES²

SW-01

SW-02

SAMPLE DATA

USCS

Symbol¹

Natural Moisture Content

Moist Unit

Weight (pcf)

Depth (feet) Gravel

Sand

Fines (%) Resistivity

(ohm-cm) Sulfates

Chlorides

ATTERBERG LIMITS3

Unconfined

Compressive Strength

(psi)

CORROSION

Liquid Limit

Plastic Limit

Plasticity Index

104002-001 Page 1 of 1 2021

ASTM D7012-14, Method C

UNIAXIAL COMPRESSIVE STRENGTH OF INTACT ROCK CORE SPECIMENS

Point ID Sample Depth

Diameter 1.86 in Length 4.17 in 22,145 lbs

L/D Ratio 2.24 8,110 psi Area 2.73 in2 Minutes

Mass (moist) 422.3 g Seconds Moist Unit Weight 141.1 pcf Intact Break Moisture Content 1.3 % Along Fracture

Stress Rate 100

Max. Compressive Strength

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

SW-01

C he ck ed

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1/

/2

Run 5

35.1 - 35.4 Feet

104002-001 Tested By: DLB Sample Descrip.: BASALT

Specimen Data and Test Results

Specimen Data: Specimen Test Results:

Date of Testing 11/10/2020 Maximum Load

Time to Failure

Sample Break Type

X

PSI/s

-0

A

ST

M

_D

_S

W -0

1, R un -5

.x ls x

/1 0/

-0

FIG. B-3

Specimen Photographs

1321 BANNOCK STREET • SUITE 200 • DENVER, COLORADO • 80204 • MAIN 303-825-3800

Point ID Sample Depth

Diameter 1.87 in Length 4.23 in 61,015 lbs

L/D Ratio 2.26 22,260 psi Area 2.74 in2 Minutes

Mass (moist) 505.6 g Seconds Moist Unit Weight 166.1 pcf Intact Break Moisture Content 1.5 % Along Fracture

Stress Rate 75

Max. Compressive Strength

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

SW-01

C he ck ed

1/

/2

Run 6

42.7 - 43.0 Feet

104002-001 Tested By: DLB Sample Descrip.: BASALT

Specimen Data and Test Results

Specimen Data: Specimen Test Results:

Date of Testing 11/10/2020 Maximum Load

Time to Failure

Sample Break Type

X

PSI/s

-0

A

ST

M

_D

_S

W -0

1, R un -6

.x

0/

-0

FIG. B-4

Point ID Sample Depth

Diameter 1.86 in Length 4.29 in 12,235 lbs

L/D Ratio 2.31 4,500 psi Area 2.72 in2 Minutes

Mass (moist) 388.3 g Seconds Moist Unit Weight 126.7 pcf Intact Break Moisture Content 0.8 % Along Fracture

Stress Rate 75

Max. Compressive Strength

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

SW-02

C he ck ed

1/

/2

Run 4

22.5 - 22.8 Feet

104002-001 Tested By: DLB Sample Descrip.: BASALT

Specimen Data and Test Results

Specimen Data: Specimen Test Results:

Date of Testing 11/10/2020 Maximum Load

Time to Failure

Sample Break Type

X

PSI/s

-0

A

ST

M

_D

_S

W -0

2, R un -4

.x

0/

-0

FIG. B-5

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Appendix C: D rilling Photogra phs

Appendix C

Drilling Photographs Figures Figure C-1: Drilling Photographs

Photograph 1. Drilling Boring SW-01

Photograph 2. Boring SW-01 drilling location.

DRILLING & SITE PHOTOGRAPHS

104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

FIG. C-1

Sheet 1 of 4

Photograph 3. Rock outcrop located above SW-01.

Photograph 4. Drilling Boring SW-02.

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

DRILLING & SITE PHOTOGRAPHS

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Sheet 2 of 4

Photograph 5. Drilling Boring SW-02

Photograph 6. Drilling Boring SW-02.

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

DRILLING & SITE PHOTOGRAPHS

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Sheet 3 of 4

Photograph 1. Drilling Boring SW-01

Photograph 7. Drilling Boring SW-02.

NM FLAP TAO B007(1)

John Dunn Bridge

Taos County, New Mexico

DRILLING & SITE PHOTOGRAPHS

2021 104002-001

SHANNON & WILSON, INC.

Geotechnical and Environmental Consultants

Sheet 4 of 4

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Important Information About Your Geotechnical Report

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