CITY of FARMINGTON 800 Municipal Drive Farmington, NM 87401-2663 (505) 599-1373 Fax (505) 599-1377

CITY OF FARMINGTON 800 Municipal Drive Farmington, NM 87401-2663 (505) 599-1373 Fax (505) 599-1377 http://www.fmtn.org

IMMEDIATE ATTENTION Civil Works for Twin Peaks Substation, BID #19-127862

ADDENDUM ONE

August 7, 2018

Notice to Bidders: The above referenced bid is hereby amended as follows:

Attached is a redline/strikeout revision of those pages in the bid document with significant changes. The changes made are as follows:

CHANGE: Bid Propsal, AF-3 Form:

Details19-127862, Page 11: Revised Bid Proposal line items. Please see revised form on our website titled, AF3FillableForm19-127862.

Drawings19-127862, Page 9: Delete map from Twin Peaks to Cottonwood Substation (this is no longer relevant to the project)

Add TP-05 Cut and Fill Staking Plan (attached)

Add GeoTechnical Engineering Report (attached)

The following questions or requests for clarification were received regarding this project. Following each question or request for clarification is the response.

1. What are the limits for the contractor verses what the Farmington Electric surveyor will be completing?

A: The four control points have been staked and are visible. The FEUS surveyor will do another TOPO of the site and calculate the volume. Construction staking and layout of the roads will be required by the Awarded contractor.

2. Will you be able to share the FEUS surveying information with us?

A: That information is already included in the plans.

3. Will you provide a CAD file of the Civil information?

A: A CAD file will be provided to the awarded contractor after they submit the signed release form which will be provided at the Pre-Construction Meeting. PURCHASING

4. Will the contractor be responsible for putting in a fence?

A: No. The fence installation is not part of this project.

5. Will any fill-dirt be needed on-site?

A: The last page of the drawings document is a map of the Twin Peaks Substation to the Cottonwood Substation. Initially, we thought you would have to get spoils from the Cottonwood site and bring them out to Twin Peaks Site. That is no longer necessary.

6. Will you have drawing for sub-grade?

A: The document TP-05 is the Cut and Fill Staking Plan and is attached to this Addendum.

7. Do you have a projected start date?

A: Late September.

8. Will soils report information be available to us?

A: Yes. The Geotechnical report is attached in this Addendum.

A pre-bid conference was held in the Farmington Musuem and Visitor's Center: 3041 E. Main Street Farmington, NM 87402 at 9:00 A.M. on August 7, 2018. The purpose of this pre-bid was to answer any questions, as might arise, with respect to the requirements and execution of the proposal. Questions resolved at this meeting are included in the recording and will be kept in the Bid File. Bidders interested in receiving the recording may obtain them by accessing the Purchasing page of the City of Farmington website, www.fmtn.org or by calling (505) 599- 1373.

Receipt of this addendum shall be noted on Form AF-1 (a) in Tab I – Bidding Requirements for the above referenced bid.

If your bid has already been submitted to this office, and this addendum will affect your bid quote, please contact this office and we will return your bid. Any bids that have been received, and are not requested to be returned will remain in this office unopened until August 28, 2018 at 2:00 P.M..

/s/ Emily Milne Emily Milne Buyer II Phone: (505) 599-1370 Fax: (505) 599-1377 Email: [email protected]

PURCHASING GAS

GAS

83 GAS

GAS 1049 82 GAS

81 GAS 82

GAS 80 81 1050 80 79 GAS 79

GAS

78 82

77 77 78 79 1052 80 81 1059 82 1053 83 84

76 1054 85 1060 1055 86 1061 1056 1057 87

1058 82 1064 83 88 81 1062 84 89 85

1000 1001 1002 1003 1004 1005 1063 1006 1065 87 89 88 86 85

1008 1009 1010 1011 1012 1013 1007

85 86 84 87

1015 1016 1017 1018 1019 1020 1014

1022 1023 1024 1025 1026 1027 1021

86 87

89 1029 1030 1031 1032 1033 1034 1028

1036 1037 1038 1039 1040 1041

1035 88

82 87 84 81 85 86 1043 1044 1045 1046 1047 1048 1042

1st Review Issued (By/Date) / 2nd Review SCALE: DRAWN BY: Issued (By/Date) / IFC (T&D) 1"=40' DEM/DBT 1 REVIEW BY CLIENT - - 3-15-18 / Issued (By/Date) DWG NO. SHEET OF IFC (FEUS) No. REVISION DESCRIPTION By Chkd DATE Issued (By/Date) /

SUPPLEMENTAL GEOTECHNICAL ENGINEERING REPORT KIRTLAND ELECTRICAL SUBSTATION KIRTLAND, NEW MEXICO

Submitted To:

Roy Waters, P.E. Farmington Electric Utility System 101 N. Browning Parkway Farmington, New Mexico 87401

Submitted By:

GEOMAT Inc. 915 Malta Avenue Farmington, New Mexico 87401

June 28, 2017 GEOMAT Project 172-2761

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Kirtland Electrical Substation

TABLE OF CONTENTS Page No. INTRODUCTION...... 1

PROPOSED CONSTRUCTION ...... 2

SITE EXPLORATION ...... 2 Field Exploration ...... 2 Laboratory Testing ...... 3

SITE CONDITIONS ...... 3

SUBSURFACE CONDITIONS ...... 4 Soil Conditions ...... 4 Groundwater Conditions ...... 5 Laboratory Test Results ...... 5

OPINIONS AND RECOMMENDATIONS ...... 5 Geotechnical Considerations ...... 5 Foundations ...... 6 Site Classification ...... 9 Lateral Earth Pressures ...... 10 Slopes ...... 10 Soil Resistivity ...... 11 Corrosivity ...... 11 Earthwork ...... 13 General Considerations ...... 13 Site Clearing ...... 13 Excavation...... 14 Foundation Preparation ...... 14 Slab Subgrade Preparation ...... 14 Fill Materials ...... 14 Placement and Compaction ...... 15 Compliance ...... 15 Drainage ...... 16 Surface Drainage ...... 16 Subsurface Drainage ...... 16

GENERAL COMMENTS ...... 16

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Kirtland Electrical Substation

TABLE OF CONTENTS (continued)

APPENDIX A Site Plan Logs of Borings Unified Soil Classification Drilling and Exploration Procedures

APPENDIX B Laboratory Test Results Laboratory Test Procedures

APPENDIX C Important Information About This Geotechnical Engineering Report (Taken From GBA)

SUPPLEMENTAL GEOTECHNICAL ENGINEERING REPORT KIRTLAND ELECTRICAL SUBSTATION KIRTLAND, NEW MEXICO GEOMAT PROJECT NO. 172-2761

INTRODUCTION

This report contains the results of our supplemental geotechnical engineering exploration for the proposed Kirtland Electrical Substation to be located approximately 2,000 feet west of the intersection of Roads 6500 and 6480 on the northern edge of Kirtland, New Mexico, as shown on the Site Plan in Appendix A of this report.

We understand that the project scope has developed since our original geotechnical engineering report for the project was performed (GEOMAT Project No, 122-1647, dated November 19, 2012). The site has been expanded an additional 150 feet to the north of the area previously explored. Dimensions and structural loads have been determined for the structures, and locations have been determined for the transmission line dead end structures and the mobile sub bay. This study is intended to supplement our original report. Copies of the original report may be requested from the City of Farmington, and should be reviewed in conjunction with this supplemental report.

The purpose of these services is to characterize and evaluate subsurface conditions at the expanded (northern) portion of the site not included in our original report, and to confirm and/or modify the recommendations in that report relative to the updated structural load information.

This report provides information and geotechnical engineering recommendations about:

 subsurface soil conditions  groundwater conditions  foundation design and construction  LPILE parameters

The opinions and recommendations contained in this report are based upon the results of field and laboratory testing, engineering analyses, and experience with similar soil conditions, structures, and our understanding of the proposed project as stated below.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 2

PROPOSED CONSTRUCTION

We understand the project will consist of the installation of an electrical substation facility including a control building, a transformer, H-frame deadend structures, mobile deadend structures, bus supports, and switch supports. The transformer will have a below-grade oil- containment moat surrounding the transformer. With the exception of an oil-containment moat around the transformer, no below-grade structures are planned. No significant cuts or fills are expected to be necessary to achieve the planned finished grades.

Dimensions and/or loads for the structures are understood to be as follows:

 Control Building: The control building will have plan dimensions of approximately 32 feet by 36 feet. Maximum structural loads will be 2.5 klf for walls and 20 kips for columns.  Transformer: The weight of the transformer will be on the order of 175 to 225 kips with approximately 180 ft-kips of overturning moment.  H-Frame Deadend Structures: The H-frame deadend structures will likely be of steel- framed construction with a height of 50 feet and a width of 40 feet. The maximum leg overturning moment will be 80 to 100 ft-kips, and maximum axial load will be 5 kips per leg.  Mobile Sub Deadend Structures: The mobile sub deadend structures will be smaller than the H-frame structures, and will have correspondingly smaller loads.  Bus Supports: The bus supports will have a maximum overturning moment of 15 ft- kips. Maximum axial and shear loads will be 1 kip and 10 kips, respectively.  Switch Supports: The switch supports will have a maximum overturning moment of 25 ft-kips. Maximum axial and shear loads will be 2 kips and 10 kips, respectively.

SITE EXPLORATION

Our scope of services performed for this project included a site reconnaissance by a staff geologist, a subsurface exploration program, laboratory testing and engineering analyses.

Field Exploration:

Subsurface conditions at the site were explored on June 6, 2017 by drilling three exploratory borings at the approximate locations shown on the Site Plan in Appendix A. The borings were drilled to depths of approximately 20 feet below existing ground surface using a CME-55 truck- mounted drill rig with continuous-flight, 7.25-inch O.D. hollow-stem auger. The borings were drilled at locations chosen and staked by the client, and were designated C-1, C-2, and C-3 to

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 3

distinguish them from the borings drilled for our original subsurface exploration in 2012 (B-1 through B-5).

The borings were continuously monitored by a geologist from our office who examined and classified the subsurface materials encountered, obtained representative samples, observed groundwater conditions, and maintained a continuous log of each boring.

Soil samples were obtained from the borings using a combination of standard 2-inch O.D. split spoon and 3-inch O.D. ring-lined barrel samplers. The samplers were driven using a 140-pound hammer falling 30 inches. The standard penetration resistance was determined by recording the number of hammer blows required to advance the sampler in six-inch increments. Representative bulk samples of subsurface materials were also obtained.

Groundwater evaluations were made in each boring at the time of site exploration. Soils were classified in accordance with the Unified Soil Classification System described in Appendix A. Boring logs were prepared and are presented in Appendix A.

Laboratory Testing:

Samples retrieved during the field exploration were transported to our laboratory for further evaluation. At that time, the field descriptions were confirmed or modified as necessary, and laboratory tests were performed to evaluate the engineering properties of the subsurface materials.

SITE CONDITIONS

The site of the Kirtland Substation is located approximately 2,000 feet west of the intersection of Roads 6500 and 6480 on the northern edge of Kirtland, New Mexico. The site is located approximately 400 feet south of an unpaved access road, and an existing substation is located approximately 400 feet northwest of the site. The portion of the site explored for this supplemental report (borings C-1 through C-3) is approximately 150 feet north-south by 300 feet east-west, and abuts the area explored for our original report (B-1 through B-5).

The site is characterized by gently rolling terrain, with roughly 3 to 5 feet of elevation differential across the supplemental portion of the site. At the time of our exploration, the site was vegetated by a sparse to moderate growth of grasses, weeds, and shrubs. No evidence of prior structural development was noted at the site.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 4

Based on a review of aerial photography, and our knowledge that an underground coal mining operation is located to the north and west of the site, it appears that subsidence cracks may exist at the ground surface roughly 100 feet northeast of the site. Subsidence cracks are known to exist in the area of the mine. Evaluation of subsidence cracks is beyond the scope of our services for this project; however, the effects of potential subsidence should be considered during design of the project.

The following photograph depicts the site at the time of our exploration.

View to the Northwest

SUBSURFACE CONDITIONS

Soil Conditions:

As presented on the Boring Logs in Appendix A, we encountered clayey soils in all of our borings from the ground surface to depths ranging from approximately 3 to 4 feet below existing ground surface. The clayey soils were generally highly plastic, stiff to very stiff and slightly damp. The clayey soils are likely residuum derived from weathering of the underlying shale.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 5

Below the clayey soils, we encountered formational shale and/or fine-grained sandstone extending to the total depths explored. The formational rock was generally moderately to highly weathered and slightly damp.

Groundwater Conditions:

Groundwater was not encountered in the borings to the depths explored. Groundwater elevations can fluctuate over time depending upon precipitation, irrigation, runoff and infiltration of surface water. We do not have any information regarding the historical fluctuation of the groundwater level in this vicinity.

Laboratory Test Results:

Laboratory analyses of representative samples indicate the shale bedrock has fines contents (silt- and/or clay-sized particles passing the U.S. No. 200 sieve) of approximately 72 percent. In-place dry densities of the shale ranged from approximately 90 to 108 pounds per cubic foot (pcf), with natural moisture contents between approximately 10 and 22 percent.

Laboratory consolidation/expansion testing was performed on a representative undisturbed ring sample of the shale bedrock obtained from boring C-2. Results of this test indicate that the shale undergoes moderate compression when subjected to anticipated foundation stresses at the existing moisture contents. When subjected to increased moisture conditions at these stresses, it undergoes significant expansion (swell). Based on the results of this test, the shale was characterized as highly expansive.

Results of all laboratory tests are presented in Appendix B.

OPINIONS AND RECOMMENDATIONS

Geotechnical Considerations:

The site is considered suitable for the proposed structures based on the geotechnical conditions encountered and tested for this report. The results of our supplemental exploration and laboratory testing indicate that subsurface conditions at the northern “supplemental” portion of the site are generally similar to those encountered during our original exploration on the southern portion.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 6

Based on the results of our original and supplemental subsurface exploration and laboratory testing, and our engineering analyses based on the updated dimensions and load information, all of the recommendations provided in our original report (GEOMAT Project No. 122-1647, dated November 19, 2012) remain valid and are included in this report. We are also providing updated recommendations for supporting the structures that were not included in our original report.

Additionally, we are providing recommended soil strength parameters for use in designing drilled shaft elements using the LPILE program. We understand that an LPILE analysis will be performed by others. GEOMAT is available to perform the LPILE analysis if requested.

The site is considered suitable for the proposed substation based on the geotechnical conditions encountered and tested for the original and supplemental reports. The clay soils and shale bedrock on the site are expansive; if these materials experience an increase in their existing moisture contents, they could cause heaving of structures supported on conventional shallow foundations and/or slabs-on-grade. Our recommendations have been formulated to reduce the potential for damage due to expansive soil movements for the building, transformer, and associated equipment. To reduce the potential movements, the equipment and building should be supported on drilled shafts bearing in the shale or sandstone. The control building should have a suspended, structural floor system.

If there are any significant deviations from the assumed finished elevations, structure locations and/or loads noted at the beginning of this report, the opinions and recommendations of this report should be reviewed and confirmed/modified as necessary to reflect the final planned design conditions.

Foundations:

Drilled Shaft Design:

Drilled shafts should bear a minimum of eight feet below finished grade, or two feet into formational shale/sandstone, whichever is deeper.

Drilled shafts should be designed on an equivalent end-bearing basis using an allowable bearing pressure of 10,000 psf for vertical downward loads. Uplift load capacities could be calculated using the weight of the drilled shaft plus an adhesion value of 600 pounds per square foot of the contact area between the concrete in the drilled shaft and the adjacent soil/rock. Since the top portion of the soil adjacent to the shaft may become disturbed during drilling, we recommend neglecting the upper two feet of soil/concrete area in the calculation of the allowable uplift capacity due to the adhesion. Good surface drainage near the foundations is important to prevent moisture buildup in the shallow soils which could cause heaving of the near-surface soils and uplift on the foundation elements.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 7

The following soil strength parameters are recommended for use in designing drilled shaft elements using the LPILE program. We recommend neglecting the upper two feet of the soil/concrete area in the calculation of the allowable lateral capacity.

Design Design Design Design Design Lateral Material Unit Friction N Cohesion Adhesion Modulus ε50 Type Wt Angle Value (psf) (psf) k (pci) (pci) ø (deg) Fat Clay 30 0.052 14 3,000 2,250 1,000 0.005

Shale 50+ 0.061 24 8,000 6,000 4,000 0.002

Drilled Shaft Construction:

Drilled shafts should be a minimum of two (2.0) feet in diameter. Shafts should not be drilled within 10 feet of another shaft while the adjacent shaft is either open or the concrete in the shaft has not been in place for at least 12 hours.

Concrete should be placed in accordance with the American Concrete Institute (ACI) Specification for the Construction of Drilled Piers (ACI 336.1-01).

Concrete may be placed by free-falling, provided that concrete is guided so as not to hit the reinforcement, hole sides, or anchor bolt assemblies (ACI 336.1-01, Section 3.5.6).

It is recommended that the following items concerning the installation of drilled shafts be addressed in the job specifications.

1. A GEOMAT representative should be present at the site during drilling to observe and document the conditions encountered and to provide alternate recommendations, if applicable. All drilled shaft installation procedures and techniques and concrete placement shall be observed and documented by qualified geotechnical personnel.

2. Holes shall be drilled or bored in such a manner as to provide the full-sized shaft diameter and length as specified on the drawings or in the specifications.

3. Before and after placement of reinforcement cages and before placing concrete, the diameter, depth, and bearing stratum of each borehole must be verified by a representative of the owner (Geotechnical Engineer).

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 8

4. Under no circumstances should concrete be allowed to free fall against shaft sides or reinforcing. Free-falling concrete should be guided so that it does not hit the reinforcement, hole sides, or anchor bolt assemblies.

5. If the Geotechnical Engineer deems the bearing stratum as not capable of providing sufficient bearing support, the shaft length shall be extended as directed, or the diameter of the shaft should be enlarged.

6. All loose material and slough shall be removed from drilled shafts before reinforcing and concrete placement. Excavate shaft bottoms to a level plane, as approved by the Geotechnical Engineer. If caving occurs or “slough” from the surface falls into the borehole after placement of the reinforcement cage, the reinforcement cage shall be removed, the bottom cleaned out, and reinforcement cage reinserted.

7. It is not anticipated that groundwater will be encountered; however, should unforeseen groundwater be encountered or should drilling mud/slurry be necessary, tremie concrete placement methods, as described below, may be used.

a. Drilled shafts shall be cleaned with a clean-out bucket, immediately before concrete placement.

b. The tremie or pump pipe shall have watertight joints.

c. During the initial concrete placement, the concrete tremie or pump pipe shall be extended to the bottom of the drilled shaft before concrete placement.

d. During placement of concrete, the bottom of the pipe shall be maintained below the top of the concrete at all times. If the seal is lost, the pipe shall be re-inserted and the operation restarted.

e. Sufficient embedment of the tremie or pump pipe in concrete shall be maintained throughout concrete placement to prevent re-entry of water. The minimum embedment depth shall be 5 feet

f. The first-placed portion of concrete flow that comes to the top of the shaft shall be wasted, as determined by the Geotechnical Engineer.

g. Under no circumstances shall concrete be allowed to free fall through water or drilling fluid.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 9

8. The placement of concrete for each drilled shaft shall be completed in one placement before commencing the placement of concrete in another.

9. Quantities of concrete placed for each drilled shaft shall be provided to the representative of the Owner.

10. Concrete shall have an ultimate compressive strength of not less than that provided for in the specifications and shall be workable and plastic so that it may be placed without segregation. A slump of 6 to 8 inches is recommended.

11. Concrete shall be cast-in-place against undisturbed earth in the holes in such a manner to provide for the exclusion of foreign matter in the concrete.

12. The Geotechnical Engineer should review drilled shaft spacing at the time of construction. In order to prevent blowout between drilled shafts, it may be necessary to place concrete and allow it to harden for at least 8 hours before drilling adjacent shafts.

The test drilling was performed using truck-mounted, CME-45 (2012) and CME-55 (2017) drill rigs with 7.25-inch-diameter augers. It is not possible to accurately correlate the auger drilling results with the ease or difficulty of excavation at the site with other types of equipment. We present the following general comments regarding excavatability for the designers’ information with the understanding that they are opinions based on the test boring data. More accurate information regarding excavatability should be evaluated by contractors or other interested parties from test excavations using the equipment that will be used during construction. Based on the conditions encountered in our test borings, we anticipate that drilling to design depths may be possible with appropriate rotary or single-flight power augers.

Final concrete quantities should be expected to exceed ideal geometric quantities, due to raveling and sloughing of the drilled shafts.

Site Classification:

Based on the subsurface conditions encountered in the borings, we estimate that Site Class C is appropriate for the site according to Table 1613.5.2 of the 2009 International Building Code. This parameter was estimated based on extrapolation of data beyond the deepest depth explored, using methods allowed by the code. Actual shear wave velocity testing/analysis and/or exploration to a depth of 100 feet were not performed as part of our scope of services for this project.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 10

Lateral Earth Pressures:

For soils above any free water surface, recommended equivalent fluid pressures for unrestrained foundation elements are presented in the following table:

 Active: Granular soil backfill (on-site sand)...... 35 psf/ft Undisturbed subsoil ...... 30 psf/ft

 Passive: Shallow foundation walls ...... 250 psf/ft Shallow column footings...... ………...... 350 psf/ft

 Coefficient of base friction: ...... 0.40 The coefficient of base friction should be reduced to 0.30 when used in conjunction with passive pressure.

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

 At rest: Granular soil backfill (on-site sand) ...... 50 psf/ft Undisturbed subsoil ...... 60 psf/ft

Fill against grade beams and retaining walls should be compacted to densities specified in Earthwork. Medium to high plasticity clay soils should not be used as backfill against retaining walls. Compaction of each lift adjacent to walls should be accomplished with hand-operated tampers or other lightweight compactors. Over compaction may cause excessive lateral earth pressures that could result in wall movement.

Slopes:

Assuming fill specifications, compaction requirements, and recommended setbacks provided in this report are followed, cut and fill slopes as steep as to 2.5:1 (horizontal:vertical) should be stable. Depending upon specific project conditions, adequate factors of safety against slope failure may be available for steeper configurations. However, such a determination would require additional analysis.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 11

Soil Resistivity:

In-situ electrical resistivity of the subsurface materials was measured on the existing ground surface during our original field exploration in 2012. The results of those tests are presented in our original report, and are also shown below for reference. We understand the results of our resistivity testing will be used by others to design a grounding system for the substation.

The resistivity measurements were performed using the Wenner four-pin method. Resistivity measurements were taken along roughly north-south and east-west trending straight lines originating near the center of the original portion of the site. Multiple measurements were taken along each line with electrode spacings of 20, 40, and 60 feet. The results of the measurements are presented in the tables below.

In-Situ Soil Resistivity Test (2012) North-South Origin at Approximate Center of Site Pin Spacing, ft 20 40 60 Reading, ohms 0.17 0.080 0.061 Resistivity, ohm-cm 651 613 701

In-Situ Soil Resistivity Test (2012) East-West Origin at Approximate Center of Site Pin Spacing, ft 20 40 60 Reading, ohms 0.130 0.100 0.021

Resistivity, ohm-cm 498 766 241

Corrosivity:

In addition to the field resistivity testing, laboratory corrosivity testing was performed on selected representative samples from our original and supplemental borings to help evaluate the potential for the subsurface materials to corrode buried metal and/or concrete. The samples were tested for pH, soluble sulfates, soluble chlorides, and electrical resistivity. Results of these tests are presented in the following table.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 12

Corrosivity Test Results

Sample Sample Resistivity Sulfates Chlorides Boring No. pH No. Depth (ft) (ohm-cm) (ppm) (ppm) B-3+B-5 13742 0 - 5 -- 307 13,100 -- (composite) 5254 C-1 10 7.36 86.9 6,720 139

Corrosion of Concrete:

The soluble sulfate contents of the samples tested were 13,100 and 6,720 ppm, which is characterized as severe to very severe (class S2 to S3) sulfate exposure according to American Concrete Institute Building Code 318, Table 4.3.1. For this level of sulfate exposure, ACI 318 recommends the use of Type V cement plus fly ash. Additionally, it recommends the use of concrete with a minimum 28-day compressive strength of 4,500 psi and a maximum water- cementitious material ratio of 0.45. Calcium chloride admixture is not permitted in concrete for this class of sulfate exposure. All concrete should be designed, mixed, placed, finished, and cured in accordance with the guidelines presented by the Portland Cement Association (PCA) and the American Concrete Institute (ACI).

Corrosion of Metals:

Corrosion of buried ferrous metals can occur when electrical current flows from the metal into the soil. As the resistivity of the soil decreases, the flow of electrical current increases, increasing the potential for corrosion. A commonly accepted correlation between soil resistivity and corrosion of ferrous metals is shown in the following table.

Resistivity (ohm-cm) Corrosivity 0 to 1,000 Severely Corrosive 1,000 to 2,000 Corrosive 2,000 to 10,000 Moderately Corrosive >10,000 Mildly Corrosive

The samples tested in the laboratory under saturated conditions had resistivity values of 307 and 86.9 ohm-cm. Based on these laboratory results and the table above, the on-site soils and rock would be characterized as severely corrosive toward ferrous metals. The potential for corrosion should be taken into account during the design process.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 13

Earthwork:

General Considerations:

The opinions contained in this report for the proposed construction are contingent upon compliance with recommendations presented in this section. Although underground facilities such as foundations, septic tanks, cesspools, basements and irrigation systems were not encountered during site reconnaissance, such features could exist and might be encountered during construction.

Site Clearing:

1. Strip and remove any existing pavement, fill, debris and other deleterious materials from the proposed substation area. Any existing structures should be completely removed from below any structure, including foundation elements and any associated development such as underground utilities, septic tanks, etc. All exposed surfaces below the building area should be free of mounds and depressions that are large enough to prevent uniform compaction.

2. If unexpected fills or underground facilities are encountered during site clearing, we should be contacted for further recommendations. All excavations should be observed by GEOMAT prior to backfill placement.

3. Stripped materials consisting of vegetation and organic materials should be removed from the site, or used to re-vegetate exposed slopes after completion of grading operations. If it is necessary to dispose of organic materials on-site, they should be placed in non-structural areas, and in fill sections not exceeding 5 feet in height.

4. Sloping areas steeper than 5:1 (horizontal:vertical) should be benched to reduce the potential for slippage between existing slopes and fills. Benches should be level and wide enough to accommodate compaction and earth moving equipment.

5. All exposed areas which will receive fill, if required, once properly cleared and benched where necessary, should be scarified to a minimum depth of eight inches, conditioned to near optimum moisture content, and compacted to at least 95% of standard proctor (ASTM D698).

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 14

Excavation:

1. We present the following general comments regarding our opinion of the excavation conditions for the designers’ information with the understanding that they are opinions based on our boring data. More accurate information regarding the excavation conditions should be evaluated by contractors or other interested parties from test excavations using the equipment that will be used during construction. Based on our subsurface evaluation it appears that shallow excavations in soils at the site will be possible using standard excavation equipment. Excavations that encounter formational rock are expected to be difficult and may necessitate the use of heavy-duty equipment and/or specialized techniques.

2. On-site soils may pump or become unstable or unworkable at high water contents. Dewatering may be necessary to achieve a stable excavation. Workability may be improved by scarifying and drying. Over-excavation of wet zones and replacement with granular materials may be necessary. Lightweight excavation equipment may be required to reduce subgrade pumping.

Foundation Preparation:

All loose and/or disturbed soils should be removed from the bottoms of drilled shafts prior to placement of reinforcing steel and/or concrete.

Slab Subgrade Preparation:

Due to the highly expansive soil/rock at the site, slabs-on-grade are not recommended. The control building should have a suspended, structural floor system. After site clearing is complete, the existing soil below the building area should be prepared as recommended in the Site Clearing section of this report. Soils should be removed as necessary to provide a minimum six-inch void space below the structural floor system.

Fill Materials:

1. The existing soils are highly plastic and expansive, and are not suitable for use as structural fill. Imported soils with low expansive potentials could be used as fill material for the following:

 general site grading  foundation backfill

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 15

2. Select granular materials should be used as backfill behind walls that retain earth.

3. On site or imported soils to be used in structural fills should conform to the following:

Percent finer by weight Gradation (ASTM C136) 3" ...... 100 No. 4 Sieve ...... 50-100 No. 200 Sieve ...... 50 Max

Maximum expansive potential (%)* ...... 1.5 * Measured on a sample compacted to approximately 95 percent of the ASTM D698 maximum dry density at about 3 percent below optimum water content. The sample is confined under a 144-psf surcharge and submerged.

Aggregate base should conform to Type I Base Course as specified in Section 303 of the 2014 New Mexico Department of Transportation (NMDOT) “Standard Specifications for Road and Bridge Construction.”

Placement and Compaction:

1. Place and compact fill in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift.

2. Un-compacted fill lifts should not exceed 10 inches loose thickness.

3. Materials should be compacted to the following:

Minimum Percent Material (ASTM D698)

Miscellaneous backfill ...... 90

4. Imported soils should be compacted at moisture contents near optimum.

Compliance:

Recommendations for drilled shafts depend upon compliance with Foundations recommendations. To assess compliance, observation and testing should be performed by GEOMAT.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 16

Drainage:

Surface Drainage:

1. Positive drainage should be provided during construction and maintained throughout the life of the proposed project. Infiltration of water into utility or foundation excavations must be prevented during construction. Planters and other surface features that could retain water in areas adjacent to the building or pavements should be sealed or eliminated.

2. Protective slopes be provided with a minimum grade of approximately 5 percent for at least 10 feet from the perimeter of the foundation. Backfill against footings, and in utility trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration.

3. Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving.

4. Sprinkler systems should not be within 5 feet of foundation walls. Irrigated landscaping adjacent to the foundation system should be minimized or eliminated.

Subsurface Drainage:

Free-draining, granular soils containing less than five percent fines (by weight) passing a No. 200 sieve should be placed adjacent to walls, which retain earth. A drainage system consisting of either weep holes or perforated drain lines (placed near the base of the wall) should be used to intercept and discharge water which would tend to saturate the backfill. Where used, drain lines should be embedded in a uniformly graded filter material and provided with adequate clean-outs for periodic maintenance. An impervious soil should be used in the upper layer of backfill to reduce the potential for water infiltration.

GENERAL COMMENTS

It is recommended that GEOMAT be retained to provide a general review of final design plans and specifications in order to confirm that grading and foundation recommendations in this report have been interpreted and implemented. In the event that any changes of the proposed project are planned, the opinions and recommendations contained in this report should be reviewed and the report modified or supplemented as necessary.

Supplemental Geotechnical Engineering Report GEOMAT Project No. 172-2761 FEUS Electrical Substation 17

GEOMAT should also be retained to provide services during excavation, grading, foundation, and construction phases of the work. Observation of footing excavations should be performed prior to placement of reinforcing and concrete to confirm that satisfactory bearing materials are present and is considered a necessary part of continuing geotechnical engineering services for the project. Construction testing, including field and laboratory evaluation of fill, backfill, pavement materials, concrete and steel should be performed to determine whether applicable project requirements have been met.

The analyses and recommendations in this report are based in part upon data obtained from the field exploration. The nature and extent of variations beyond the location of test borings may not become evident until construction. If variations then appear evident, it may be necessary to re- evaluate the recommendations of this report.

Our professional services were performed using that degree of care and skill ordinarily exercised, under similar circumstances, by reputable geotechnical engineers practicing in this or similar localities at the same time. No warranty, express or implied, is intended or made. We prepared the report as an aid in design of the proposed project. This report is not a bidding document. Any contractor reviewing this report must draw his own conclusions regarding site conditions and specific construction equipment and techniques to be used on this project.

This report is for the exclusive purpose of providing geotechnical engineering and/or testing information and recommendations. The scope of services for this project does not include, either specifically or by implication, any environmental assessment of the site or identification of contaminated or hazardous materials or conditions. If the owner is concerned about the potential for such contamination, other studies should be undertaken. This report has also not addressed any geologic hazards that may exist on or near the site.

This report may be used only by the Client and only for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both on and off site), or other factors may change over time and additional work may be required with the passage of time. Any party, other than the Client, who wishes to use this report, shall notify GEOMAT in writing of such intended use. Based on the intended use of the report, GEOMAT may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements, by the Client or anyone else, will release GEOMAT from any liability resulting from the use of this report by an unauthorized party.

Appendix A

915 Malta Avenue Farmington, NM 87401 Tel (505) 327-7928 Borehole C-1 Fax (505) 326-5721 Page 1 of 1

Project Name: Kirtland Electrical Substation Date Drilled: 6/6/2017 Project Number: 172-2761 Latitude: Not Determined Client: Farmington Electric Utility System Longitude: Not Determined Site Location: Kirtland, New Mexico Elevation: Not Determined Rig Type: CME-55 Boring Location: See Site Plan Drilling Method: 7.25" O.D. Hollow Stem Auger Groundwater Depth: Not Encountered Sampling Method: Ring and Split spoon samples Logged By: SY Hammer Weight: 140 lbs Remarks: None Hammer Fall: 30 inches

Laboratory Results

Soil Description (pcf) Index Depth (ft) Recovery Blows per 6" Moisture Soil Symbol Plasticity & Length (in) & Length % Passing Material Type Sample Type Sample #200 Sieve Dry Density Content (%) Sandy fat CLAY, tan, very stiff, slightly damp 1 CH 2 12-11-15 R 18 3 92.8 47 26 17.2 SHALE, gray-green, weakly fissile/friable, slightly damp, 4 orange mottling and salt nodules

15-15-14 SS 5 18 6 7

RK 8 9 10 104.9 10.2 28-50/5 R 11 11 12 13 SANDSTONE, tan to green-gray, fine grained, slightly damp, 14 weakly to moderately cemented

14-43- SS 15 50/3 15 16 RK 17 18 19 gray with orange mottling 31-30/1 SS 20 7 21 Total Depth 20½ feet 22 23 24 25 A = Auger Cuttings R = Ring-Lined Barrel Sampler SS = Split Spoon G = Manual Grab Sample GEOMAT 172-2761.GPJ GEOMAT.GDT 6/28/17 GEOMAT172-2761.GPJ 915 Malta Avenue Farmington, NM 87401 Tel (505) 327-7928 Borehole C-2 Fax (505) 326-5721 Page 1 of 1

Laboratory Results

Soil Description (pcf) Index Depth (ft) Recovery Blows per 6" Moisture Soil Symbol Plasticity & Length (in) & Length % Passing Material Type Sample Type Sample #200 Sieve Dry Density Content (%) Sandy fat CLAY, green-gray to tan, very stiff, slightly damp 1 trace salt nodules 2 10-16-18 SS CH 18 3 4 5 90.0 72 21.6 20-19-22 R SHALE, dark gray-purple, fissile/friable, slightly damp 18 6 7 8 9

12-19-24 SS 10 green-gray with orange mottling 18 11 RK 12 13 14

50/6 R 15 6 16 17 18 SANDSTONE, light tan-gray, fine grained, slightly damp, 19 RK moderatedly weathered 50/4 SS 20 4 21 Total Depth 20½ feet 22 23 24 25 A = Auger Cuttings R = Ring-Lined Barrel Sampler SS = Split Spoon G = Manual Grab Sample GEOMAT 172-2761.GPJ GEOMAT.GDT 6/28/17 GEOMAT172-2761.GPJ 915 Malta Avenue Farmington, NM 87401 Tel (505) 327-7928 Borehole C-3 Fax (505) 326-5721 Page 1 of 1

Laboratory Results

Soil Description (pcf) Index Depth (ft) Recovery Blows per 6" Moisture Soil Symbol Plasticity & Length (in) & Length % Passing Material Type Sample Type Sample #200 Sieve Dry Density Content (%) Sandy fat CLAY, tan-green, very stiff, slightly damp 1 CH 2 10-9-13 SS 18 3 SHALE, green-gray with orange mottling, slightly damp 4 5 108.2 12.9 25-44- R 50/3 trace salt nodules 9 6 7 8 9

21-29-35 SS 10 Purple-gray, fissile/friable, highly weathered 18 11 12 RK 13 14

27-50/5 R 15 11 16 17 18 19

41-39-40 SS 20 moderately weathered, damp 18 21 22 Total Depth 21½ feet 23 24 25 A = Auger Cuttings R = Ring-Lined Barrel Sampler SS = Split Spoon G = Manual Grab Sample GEOMAT 172-2761.GPJ GEOMAT.GDT 6/28/17 GEOMAT172-2761.GPJ UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE Group DENSITY CRITERIA Major Divisions Symbols Typical Names

Well-graded gravels and gravel-sand Standard Penetration Test GW mixtures, little or no fines Density of Granular Soils Clean Gravels Gravels Poorly graded gravels and gravel-sand Penetration GP Resistance, N 50% or more of mixtures, little or no fines (blows/ft.) Relative Density coarse fraction retained on No. 4 GM Silty gravels, gravel-sand-silt mixtures sieve Gravels with 0-4 Very Loose Coarse- Fines Clayey gravels, gravel-sand-clay Grained Soils GC mixtures 5-10 Loose

More than 50% Well-graded sands and gravelly sands, retained on No. SW little or no fines 11-30 Medium Dense 200 sieve Clean Sands Poorly graded sands and gravelly Sands SP sands, little or no fines More than 50% of 31-50 Dense coarse fraction passes No. 4 sieve SM Silty sands, sand-silt mixtures Sands with >50 Very Dense Fines SC Clayey sands, sand-clay mixtures Standard Penetration Test Density of Fine-Grained Soils

Inorganic silts, very fine sands, rock Penetration Unconfined ML flour, silty or clayey fine sands Resistance, N Compressive (blows/ft.) Consistency Strength (Tons/ft2) Silts and Clays Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, Liquid Limit 50 or less CL silty clays, lean clays <2 Very Soft <0.25 Fine-Grained Soils Organic silts and organic silty clays of OL low plasticity 2-4 Soft 0.25-0.50 50% or more Inorganic silts, micaceous or passes MH diatomaceous free sands or silts, elastic No. 200 sieve silts 4-8 Firm 0.50-1.00

Silts and Clays Inorganic clays of high plasticity, fat CH clays Liquid Limit greater than 50 8-15 Stiff 1.00-2.00

Organic clays of medium to high OH plasticity 15-30 Very Stiff 2.00-4.00

Highly Organic Soils PT Peat, mucic & other highly organic soils >30 Hard >4.0 U.S. Standard Sieve Sizes

>12'' 12'' 3" 3/4" #4 #10 #40 #200 Boulders Cobbles Gravel Sand Silt or Clay coarse fine coarse medium fine

MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS Dry Absence of moist, dusty, dry to the touch trace 0-5% R Ring Sample Slightly Damp Below optimum moisture content for compaction few 5-10% S SPT Sample Moist Near optimum moisture content, will moisten the hand little 10-25% B Bulk Sample Very Moist Above optimum moisture content some 25-45% ▼ Ground Water Wet Visible free water, below water table mostly 50-100%

BASIC LOG FORMAT: Group name, Group symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum, coarse particles, etc.

EXAMPLE: SILTY SAND w/trace silt (SM-SP), Brown, loose to med. Dense, fine to medium grained, damp

UNIFIED SOIL CLASSIFICATION SYSTEM

TEST DRILLING EQUIPMENT & PROCEDURES

Description of Subsurface Exploration Methods

Drilling Equipment – Truck-mounted drill rigs powered with gasoline or diesel engines are used in advancing test borings. Drilling through soil or softer rock is performed with hollow- stem auger or continuous flight auger. Carbide insert teeth are normally used on bits to penetrate soft rock or very strongly cemented soils which require blasting or very heavy equipment for excavation. Where refusal is experienced in auger drilling, the holes are sometimes advanced with tricone gear bits and NX rods using water or air as a drilling fluid.

Sampling Procedures - Dynamically driven tube samples are usually obtained at selected intervals in the borings by the ASTM D1586 test procedure. In most cases, 2” outside diameter, 1 3/8” inside diameter, samplers are used to obtain the standard penetration resistance. “Undisturbed” samples of firmer soils are often obtained with 3” outside diameter samplers lined with 2.42” inside diameter brass rings. The driving energy is generally recorded as the number of blows of a 140-pound, 30-inch free fall drop hammer required to advance the samplers in 6- inch increments. These values are expressed in blows per foot on the boring logs. However, in stratified soils, driving resistance is sometimes recorded in 2- or 3-inch increments so that soil changes and the presence of scattered gravel or cemented layers can be readily detected and the realistic penetration values obtained for consideration in design. “Undisturbed” sampling of softer soils is sometimes performed with thin-walled Shelby tubes (ASTM D1587). Tube samples are labeled and placed in watertight containers to maintain field moisture contents for testing. When necessary for testing, larger bulk samples are taken from auger cuttings. Where samples of rock are required, they are obtained by NX diamond core drilling (ASTM D2113).

Boring Records - Drilling operations are directed by our field engineer or geologist who examines soil recovery and prepares boring logs. Soils are visually classified in accordance with the Unified Soil Classification System (ASTM D2487), with appropriate group symbols being shown on the logs.

Appendix B

SAMPLE BORING ASTM D698 MOISTURE DENSITY ATTERBERG LIMITS SWELL CONSOL % PASS LAB NO. DEPTH CLASSIFICATION NO. CONT. (%) (%) TEST #200 SIEVE (ft) Density Moisture WET (pcf) DRY (pcf) LL PL PI

5214 B-1 3 - - 17.2 108.7 92.8 52 26 26 - - - Shale

5215 B-1 10 - - 10.2 115.7 104.9 ------Shale

5213 B-2 5 - - 21.6 109.4 90.0 - - - - Attached 72 Shale

5216 B-3 5 - - 12.9 122.1 108.2 ------Shale

Project Kirtland Electrical Substation

Job No. 172-2761 SUMMARY OF SOIL TESTS Location Kirtland, New Mexico

Date of Exploration 6/6/2017 PROJECT: Kirtland Electrical Substation JOB NO: 172-2761 CLIENT: Farmington Electric Utility System WORK ORDER NO: NA MATERIAL: SHALE LAB NO: 5213 SAMPLE SOURCE: B-2 @ 5' DATE SAMPLED: 6/6/2017 SAMPLE PREP.: In Situ SAMPLED BY: SY

ONE-DIMENSIONAL CONSOLIDATION PROPERTIES OF SOILS (ASTM D2435)

INITIAL VOLUME (cu.in) 4.60 FINAL VOLUME (cu.in) 4.96 INITIAL MOISTURE CONTENT 21.6% FINAL MOISTURE CONTENT 34.8% INITIAL DRY DENSITY(pcf) 90.0 FINAL DRY DENSITY(pcf) 83.2 INITIAL DEGREE OF SATURATION 55% FINAL DEGREE OF SATURATION 77% INITIAL VOID RATIO 0.85 FINAL VOID RATIO 0.99 ESTIMATED SPECIFIC GRAVITY 2.651 SATURATED AT 0.5 tsf

0 Consolidation (% of Initial Height) Initial of (% Consolidation

-1

-2

-3

-4

-5 0.01 0.1 1 10 Surcharge Pressure (tsf) In Situ Moisture Condition Saturation Condition

LABORATORY TESTING PROCEDURES

Consolidation Tests: One-dimensional consolidation tests are performed using “Floating-ring” type consolidometers. The test samples are approximately 2.5 inches in diameter and 1.0 inch high and are usually obtained from test borings using the dynamically-driven ring samplers. Test procedures are generally as outlined in ASTM D2435. Loads are applied in several increments to the upper surface of the test specimen and the resulting deformations are recorded at selected time intervals for each increment. Samples are normally loaded in the in-situ moisture conditions to loads which approximate the stresses which will be experienced by the soils after the project is completed. Samples are usually then submerged to determine the effect of increased moisture contents on the soils. Each load increment is applied until compression/expansion of the sample is essentially complete (normally movements of less than 0.0003 inches/hour). Porous stones are placed on the top and bottom surfaces of the samples to facilitate introduction of the moisture.

Expansion Tests: Tests are performed on either undisturbed or recompacted samples to evaluate the expansive potential of the soils. The test samples are approximately 2.5 inches in diameter and 1.0 inch high. Recompacted samples are typically remolded to densities and moisture contents that will simulate field compaction conditions. Surcharge loads normally simulate those which will be experienced by the soils in the field. Surcharge loads are maintained until the expansion is essentially complete.

Atterberg Limits/Maximum Density/Optimum Moisture Tests: These tests are performed in accordance with the prescribed ASTM test procedures.

Appendix C

Important Information about This Geotechnical-Engineering Report

Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.

While you cannot eliminate all such risks, you can manage them. The following information is provided to help.

The Geoprofessional Business Association (GBA) Typical changes that could erode the reliability of this report include has prepared this advisory to help you – assumedly those that affect: a client representative – interpret and apply this • the site’s size or shape; geotechnical-engineering report as effectively • the function of the proposed structure, as when it’s as possible. In that way, clients can benefit from changed from a parking garage to an office building, or from a light-industrial plant to a refrigerated warehouse; a lowered exposure to the subsurface problems • the elevation, configuration, location, orientation, or that, for decades, have been a principal cause of weight of the proposed structure; construction delays, cost overruns, claims, and • the composition of the design team; or disputes. If you have questions or want more • project ownership. information about any of the issues discussed below, contact your GBA-member geotechnical engineer. As a general rule, always inform your geotechnical engineer of project Active involvement in the Geoprofessional Business changes – even minor ones – and request an assessment of their Association exposes geotechnical engineers to a impact. The geotechnical engineer who prepared this report cannot accept wide array of risk-confrontation techniques that can responsibility or liability for problems that arise because the geotechnical be of genuine benefit for everyone involved with a engineer was not informed about developments the engineer otherwise would have considered. construction project. This Report May Not Be Reliable Geotechnical-Engineering Services Are Performed for Do not rely on this report if your geotechnical engineer prepared it: Specific Purposes, Persons, and Projects • for a different client; Geotechnical engineers structure their services to meet the specific • for a different project; needs of their clients. A geotechnical-engineering study conducted • for a different site (that may or may not include all or a for a given civil engineer will not likely meet the needs of a civil- portion of the original site); or works constructor or even a different civil engineer. Because each • before important events occurred at the site or adjacent geotechnical-engineering study is unique, each geotechnical- to it; e.g., man-made events like construction or engineering report is unique, prepared solely for the client. Those who environmental remediation, or natural events like floods, rely on a geotechnical-engineering report prepared for a different client droughts, earthquakes, or groundwater fluctuations. can be seriously misled. No one except authorized client representatives should rely on this geotechnical-engineering report without first Note, too, that it could be unwise to rely on a geotechnical-engineering conferring with the geotechnical engineer who prepared it. And no one report whose reliability may have been affected by the passage of time, – not even you – should apply this report for any purpose or project except because of factors like changed subsurface conditions; new or modified the one originally contemplated. codes, standards, or regulations; or new techniques or tools. If your geotechnical engineer has not indicated an “apply-by” date on the report, Read this Report in Full ask what it should be, and, in general, if you are the least bit uncertain Costly problems have occurred because those relying on a geotechnical about the continued reliability of this report, contact your geotechnical engineering report did not read it in its entirety. Do not rely on an engineer before applying it. A minor amount of additional testing or executive summary. Do not read selected elements only. Read this report analysis – if any is required at all – could prevent major problems. in full. Most of the “Findings” Related in This Report Are You Need to Inform Your Geotechnical Engineer Professional Opinions about Change Before construction begins, geotechnical engineers explore a site’s Your geotechnical engineer considered unique, project-specific factors subsurface through various sampling and testing procedures. when designing the study behind this report and developing the Geotechnical engineers can observe actual subsurface conditions only at confirmation-dependent recommendations the report conveys. A few those specific locations where sampling and testing were performed. The typical factors include: data derived from that sampling and testing were reviewed by your • the client’s goals, objectives, budget, schedule, and geotechnical engineer, who then applied professional judgment to risk-management preferences; form opinions about subsurface conditions throughout the site. Actual • the general nature of the structure involved, its size, sitewide-subsurface conditions may differ – maybe significantly – from configuration, and performance criteria; those indicated in this report. Confront that risk by retaining your • the structure’s location and orientation on the site; and geotechnical engineer to serve on the design team from project start to • other planned or existing site improvements, such as project finish, so the individual can provide informed guidance quickly, retaining walls, access roads, parking lots, and whenever needed. underground utilities. This Report’s Recommendations Are perform their own studies if they want to, and be sure to allow enough Confirmation-Dependent time to permit them to do so. Only then might you be in a position The recommendations included in this report – including any options to give constructors the information available to you, while requiring or alternatives – are confirmation-dependent. In other words,they are them to at least share some of the financial responsibilities stemming not final, because the geotechnical engineer who developed them relied from unanticipated conditions. Conducting prebid and preconstruction heavily on judgment and opinion to do so. Your geotechnical engineer conferences can also be valuable in this respect. can finalize the recommendationsonly after observing actual subsurface conditions revealed during construction. If through observation your Read Responsibility Provisions Closely geotechnical engineer confirms that the conditions assumed to exist Some client representatives, design professionals, and constructors do actually do exist, the recommendations can be relied upon, assuming not realize that geotechnical engineering is far less exact than other no other changes have occurred. The geotechnical engineer who prepared engineering disciplines. That lack of understanding has nurtured this report cannot assume responsibility or liability for confirmation- unrealistic expectations that have resulted in disappointments, delays, dependent recommendations if you fail to retain that engineer to perform cost overruns, claims, and disputes. To confront that risk, geotechnical construction observation. engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate This Report Could Be Misinterpreted where geotechnical engineers’ responsibilities begin and end, to help Other design professionals’ misinterpretation of geotechnical- others recognize their own responsibilities and risks. Read these engineering reports has resulted in costly problems. Confront that risk provisions closely. Ask questions. Your geotechnical engineer should by having your geotechnical engineer serve as a full-time member of the respond fully and frankly. design team, to: • confer with other design-team members, Geoenvironmental Concerns Are Not Covered • help develop specifications, The personnel, equipment, and techniques used to perform an • review pertinent elements of other design professionals’ environmental study – e.g., a “phase-one” or “phase-two” environmental plans and specifications, and site assessment – differ significantly from those used to perform • be on hand quickly whenever geotechnical-engineering a geotechnical-engineering study. For that reason, a geotechnical- guidance is needed. engineering report does not usually relate any environmental findings, conclusions, or recommendations; e.g., about the likelihood of You should also confront the risk of constructors misinterpreting this encountering underground storage tanks or regulated contaminants. report. Do so by retaining your geotechnical engineer to participate in Unanticipated subsurface environmental problems have led to project prebid and preconstruction conferences and to perform construction failures. If you have not yet obtained your own environmental observation. information, ask your geotechnical consultant for risk-management guidance. As a general rule, do not rely on an environmental report Give Constructors a Complete Report and Guidance prepared for a different client, site, or project, or that is more than six Some owners and design professionals mistakenly believe they can shift months old. unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent Obtain Professional Assistance to Deal with Moisture the costly, contentious problems this practice has caused, include the Infiltration and Mold complete geotechnical-engineering report, along with any attachments While your geotechnical engineer may have addressed groundwater, or appendices, with your contract documents, but be certain to note water infiltration, or similar issues in this report, none of the engineer’s conspicuously that you’ve included the material for informational services were designed, conducted, or intended to prevent uncontrolled purposes only. To avoid misunderstanding, you may also want to note migration of moisture – including water vapor – from the soil through that “informational purposes” means constructors have no right to rely building slabs and walls and into the building interior, where it can on the interpretations, opinions, conclusions, or recommendations in cause mold growth and material-performance deficiencies. Accordingly, the report, but they may rely on the factual data relative to the specific proper implementation of the geotechnical engineer’s recommendations times, locations, and depths/elevations referenced. Be certain that will not of itself be sufficient to prevent moisture infiltration. Confront constructors know they may learn about specific project requirements, the risk of moisture infiltration by including building-envelope or mold including options selected from the report, only from the design specialists on the design team. Geotechnical engineers are not building- drawings and specifications. Remind constructors that they may envelope or mold specialists.

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