Amendment_2_-_BATB_Lagoon_Replacement_-_Issued_0002.pdf

(x)

140L3624R0004 x x

1 copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted ; or (c) By separate letter or electronic communication which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGEMENT TO BE

RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR

OFFER. If by virtue of this amendment you desire to change an offer already submitted , such change may be made by letter or electronic communication, provided each letter or electronic communication makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

x

LMA

BILLINGS MT 59101

5001 SOUTHGATE DR

BLM MT-STATE OFCMT935

02/28/20240002

13. THIS ITEM ONLY APPLIES TO MODIFICATION OF CONTRACTS/ORDERS. IT MODIFIES THE CONTRACT/ORDER NO. AS DESCRIBED IN ITEM 14.

12. ACCOUNTING AND APPROPRIATION DATA (If required) is not extended.is extended, Items 8 and 15, and returning

Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended , by one of the following methods: (a) By completing

The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offers

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

FACILITY CODE CODE

10B. DATED (SEE ITEM 13)

10A. MODIFICATION OF CONTRACT/ORDER NO.

9B. DATED (SEE ITEM 11)

9A. AMENDMENT OF SOLICITATION NO.

CODE

8. NAME AND ADDRESS OF CONTRACTOR (No., street, county, State and ZIP Code)

7. ADMINISTERED BY (If other than Item 6)CODE 6. ISSUED BY

PAGE OF PAGES

4. REQUISITION/PURCHASE REQ. NO.3. EFFECTIVE DATE2. AMENDMENT/MODIFICATION NO. 5. PROJECT NO. (If applicable)

1. CONTRACT ID CODE

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT

02/01/2024

CHECK ONE A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority) appropriation data, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(b).

E. IMPORTANT: Contractor is not is required to sign this document and return __________________ copies to the issuing office.

ORDER NO. IN ITEM 10A.

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)

Project Title: Billings Retardant Air Tanker (BRAT) Base Retardant System Comprehensive

Condition Assessment (CCA) / Design - Phase I, Billings, Montana.

See Page 2 of 50 for changes incorporated by this amendment.

16A. NAME AND TITLE OF CONTRACTING OFFICER (Type or print)15A. NAME AND TITLE OF SIGNER (Type or print)

15C. DATE SIGNED 16B. UNITED STATES OF AMERICA 15B. CONTRACTOR/OFFEROR 16C. DATE SIGNED

(Signature of person authorized to sign) (Signature of Contracting Officer)

Christine Mundt

STANDARD FORM 30 (REV. 11/2016)

Prescribed by GSA FAR (48 CFR) 53.243

Previous edition unusable

Except as provided herein, all terms and conditions of the document referenced in Item 9 A or 10A, as heretofore changed, remains unchanged and in full force and effect .

BLM - Montana State Office (Attn: C. Mundt) 5001 Southgate Drive Billings, MT 59101

OR

via email to BLM_MT_Procurement@blm.gov

Solicitation No: 140L3624R0004 PROJECT DESCRIPTION: BRAT Base Retardant System CCA / Design – Phase I

Amendment No. 0002

Description of Changes - This amendment incorporates the following information:

1. In Section J, “List of Documents, Exhibits and Other Attachments,” include the new document herby incorporated by this amendment entitled “Attachment 12 – Geotechnical Investigation Report.”

2. For informational purposes only, the Government is providing the Second Site Visit Attendance Records from the organized site visit that the Government held on February 22, 2024, at 10:00 am Mountain Time.

3. The Government is providing the attached second round of Questions received from interested offerors and the associated Answers provided by the Government.

Acknowledgement - See Block 11 above regarding how to acknowledge this amendment. The Government must receive the acknowledgement at the place designated for receipt of offers (See Block 8 of the Standard Form 1442).

Proposal Response Date - The hour and date for receipt of proposals remains unchanged as 5:00 pm Mountain Time on March 4, 2024.

Third Party – If you have given a copy of the solicitation to someone else, please forward this amendment accordingly.

SITE INSPECTION TOUR / PREBID CONFERENCE RECORD

SECOND ORGANIZED SITE VISIT

The Government strongly urges offerors to inspect the site to gain a better understanding of the work requirements and to satisfy themselves regarding all general and local conditions that may affect the cost of performance. In no event shall failure to inspect the site constitute grounds for a claim after award.

Solicitation Number: 140L3624R0004 Project Title: Billings Retardant Air Tanker (BRAT) Base Retardant System Comprehensive Condition Assessment (CCA) / Design – Phase I, Billings, Montana Date and Time: Thursday, February 22, 2024 at 10:00 am Mountain Time Meeting Place(s): Billings Retardant Air Tanker Base; 1299 Rimtop Drive; Billings, MT 59105 Conducted by: Tanner Cahill, Bureau of Land Management District Civil Engineer

Attended by:

Name Firm

Dane Swartz Askin Construction

Dennis Ross Askin Construction

Solicitation No: 140L3623R0004

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SECOND SET OF QUESTIONS AND ANSWERS

Offerors shall submit questions by February 26, 2024, at 5:00 pm, Mountain Time. Questions submitted after this date and time will not be accepted.

Offerors for this RFP, including subcontractors and teammates, shall consolidate questions related to this solicitation and site visit in a Request for Information (RFI) formatted Word document. Any RFI is to be emailed as an editable attachment to Christine Mundt (cmundt@blm.gov) with the subject line: RFI – 140L3624R0004 BRAT Base Retardant System CCA / Design – Phase I. Only written RFI’s will be considered and responded to. BLM responses to the RFI will be posted as an amendment to the solicitation on https://sam.gov/content/opportunities.

Solicitation Number: 140L3624R0004 Project Title: Billings Retardant Air Tanker (BRAT) Base Retardant System Comprehensive Condition Assessment (CCA) / Design – Phase I, Billings, Montana

Q8: This project does not appear to have any Geomembrane Liners in the plans or specs. Is this accurate?

A8: Geomembrane Liners will be used for the new pond liners under Phase Two of the project and are therefore NOT included in this solicitation/requirement.

Q9: Are the low profile barricades the responsibility of the contractor?

A9: Yes, they are the contractors responsibility.

Q10: Is there a Geotech report for this project?

A10: Attachment 12 – “Geotechnical Investigation Report” is hereby incorporated by this amendment. This is an old (April 2005) geotechnical report for an office additional up at the BRAT.

Q11: Is this project tax exempt?

A11: No

Q12: The solicitation states to hold pricing for 120 days. Pricing is still constantly fluctuating from suppliers making this a difficult timeline to hold. Can this be reduced to 60 days?

A12: No. The 120 days acceptance is the maximum amount of time the Government is requesting offerors to honor their pricing for Government acceptance after the date offers are due.

Q13: What is the anticipated NTP date for this project?

A13: Proposals are currently due on March 4, 2024, at BLM's Montana State Office, 5001 Southgate, Billings, Montana. Offerors may submit electronic proposals as a response to the anticipated solicitation. Electronic proposals will be subject to the same rules as paper proposals. The Government anticipates award of this procurement on or around March 22, 2024. The successful offeror shall submit appropriate performance and payment bonds within 10 days in accordance with FAR 52.228-15. The Government anticipates issuing the Notice to Proceed after acceptable bonds have been received and the Preconstruction Conference (FAR 52.236-

26) has been conducted.

Q14: Can a site visit list be provided for the 2nd site visit please?

Q14: Yes, it is included with Amendment Number 0002.

Q15: Will option items be awarded with base bid items, or does the government intend to award options at a later date?

A15: Depending on availability of funding, the Government intends to award all items listed in the Base Price Schedule and all items listed in the Option for Increased Quantities – Separately Priced Line Item Price Schedule. BLM will pay the actual quantities for Items 11, 12, and 13 used by the contractor during performance and as evidenced by the Quantity Survey Clause (FAR 52.236-16).

Q16: Please confirm the length of time our pricing for option items need to be valid for.

A16: The 120 days acceptance period after the date offer are due applies to the Option for Increased Quantity Schedule.

Q17: Is the period of no construction from June 1 to Sept 30 applicable to this project?

A17: Yes. Based on past experience, the Government prefers no construction between June 1 and September 30, but this may vary based on current fire season activities. The Government will require coordination of on-site work and the current fire season.

Q18: Please confirmed red lined as-builts are acceptable.

A18: Redlined as-built plans are acceptable as long as they are electronic. Reference local clause “Drawings” under Section H and FAR clause 52.236-21 Alternate II.

Q19: Are any specific permits required for working at this location?

A19: Contractor is responsible for obtaining any necessary permits for constructions, if any. Please reference FAR clause 52.236-7.

Q20: Please confirm no sod is required in disturbed areas.

A20: Please refer to the Turf and Grasses section of the specification.

Q21: Please confirm contractor is not responsible for watering or maintaining seed after demobilization.

A21: Please refer to the Turf and Grasses section of the specification. The contractor will not be responsible for watering after construction.

Q22: Drawings state for two employees to obtain badging. However, please confirm only ONE personnel from the general contractor is required to be onsite at all times.

A22: Yes. Please in accordance with airport policy and police on their badging requirements.

Q23: What bid item did you account for the vault coring?

A23: Include the concrete coring work in the bid item for concrete work.

SECTION J – LIST OF DOCUMENTS, EXHIBITS AND OTHER ATTACHMENTS

NUMBER DESCRIPTION

NUMBER

OF

PAGES

Technical Specifications - U.S. Department of the Interior Bureau of Land Management BRAT Base Retardant System CCA / Design – Phase I (October 2022)

Technical Drawings – U.S. Department of the Interior Bureau of Land Management BRAT Base Retardant System CCA / Design Phase 1

Technical Photographs - U.S. Department of the Interior Bureau of Land Management BRAT Base Retardant System CCA / Design Phase 1

4 General Decision Number: MT20240068 (01/05/2024) 9 5 Reference List 2 6 Past Performance Questionnaire (PPQ) 2 7 Financial Responsibility Required Documentation 1 8 Bid Bond (Standard Form 24) 2 9 Performance Bond (Standard Form 25) 2 10 Payment Bond (Standard Form 25A) 2 11 Release of Claims (DI-137 – July 1996) 1 12 Geotechnical Investigation Report – April 20, 2005 42

Solicitation No: 140L3623R0004

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GEOTECHNICAL INVESTIGATION REPORT

PROPOSED BLM OFFICE ADDITION

AND REMODEL

111 GARRYOWEN ROAD

MILES CITY, MONTANA

April 20, 2005 Project No. 05-117-01

Prepared for:

LA Olson & Associates Company 2526 Grand Avenue

Billings, Montana 59102

Prepared by:

Rimrock Engineering, Inc.

350 S. Billings Boulevard, Suite 4A

Billings, Montana 59101

April 20, 2005

LA Olson & Associates 2526 Grand Avenue Billings, MT 59102

Attention: Mr. Mark Olson

SUBJECT: Geotechnical Investigation Report Proposed BLM Office Addition and Remodel Miles City, Montana

Dear Mr. Olson:

The attached report presents the results of our geotechnical investigation for the proposed BLM Office Addition and Remodel to be located at 111 Garryowen Road in Miles City, Montana. Our work consisted of subsurface exploration, laboratory testing, engineering analyses, and preparation of this report.

Based on our work completed to date, we have drawn the following general conclusions:

• The borings for the building additions and parking lots were covered by asphalt, crushed base course, or grass in the landscaped areas. Below the surface layers we encountered lean clay and sandy silty clay down to depths ranging from 6 to 15 feet.

Below the fine grained soils we encountered dense gravel and sand at depths from 11 to 14.8 feet below the existing site grades. Groundwater was encountered in some of the borings at a depths ranging from 11 to 14 feet below site grades during our investigation. The lean clay encountered in our investigation is moderately compressible and has a low swell potential. The lean clay soils were stiff to very stiff near the surface turning soft to very soft 3 to 4 feet below the existing surface.

• Conventional spread and continuous footings may be utilized to support structural loads. Foundations designed and constructed in accordance with the recommendations of this geotechnical report will require over-excavation and replacement with structural fill.

05-117-01 Page 1 of 2 April 20, 2005 Rimrock Engineering, Inc.

These and other conclusions and recommendations, along with restrictions and limitations on these conclusions, are discussed in the attached report.

We appreciate this opportunity to be of service to you, and look forward to future endeavors. If you have any questions regarding this report or need additional information or services, please feel free to call one of the undersigned.

Sincerely, RIMROCK ENGINEERING, INC.

Robert W. Kukes, P.E. Wade K. Reynolds Principal Staff Geologist

Enclosures: Report (3 Bound)

05-117-01 Page 2 of 2 April 20, 2005

TABLE OF CONTENTS

PAGE

PROPOSED BLM BUILDING ADDITIONS

1.0 INTRODUCTION AND SCOPE

1.1 Project Description

1.2 Purpose and Scope of Work

1.3 Authorization

1.4 References

2.0 METHODS OF STUDY

2.1 Field Exploration

2.2 Laboratory Testing

3.0 DISCUSSION

3.1 Site Conditions

3.2 Subsurface Conditions

3.3 Laboratory Test Results

3.4 Analytical Methods

4.0 CONCLUSIONS

5.0 RECOMMENDATIONS

5.1 Site Clearing and Preparation

5.2 Earthwork

5.2.1 General Site Grading

5.2.2 Temporary Unconfined Excavations

5.2.3 Temporary Trench Excavation and Backfill

5.3 Foundations

5.4 Concrete Slab-on-Grade Construction

5.5 Pavement Sections

5.6 Site Drainage

5.7 Soil Corrosion and Reactivity

6.0 ADDITIONAL SERVICES

6.1 Project Bid Documents

6.2 Construction Observation/Testing and Plan Review

7.0 LIMITATIONS

APPENDICES

A Plates B Suggested Specifications for Earthwork and Pavement Construction C Application for Authorization to Use

05-117-01 June 28, 2007

GEOTECHNICAL INVESTIGATION REPORT

PROPOSED BLM BUILDING ADDITIONS

111 GARRYOWEN ROAD

MILES CITY, MONTANA

1.0 INTRODUCTION AND SCOPE

1.1 Project Description

This report presents the results of our geotechnical investigation for the proposed BLM Building Additions to be located at 111 Garryowen Road in Miles City, Montana. The site location is shown on the attached Vicinity Map (Plate 1). We understand that the project will include construction of two additions to the main office building and improvements to the adjacent parking areas. The building additions will be wood framed construction with concrete foundation, surrounded by paved parking and landscaped areas. It is not anticipated that earthwork to level the site will require cuts or fills of more than 3 feet, except in landscape areas.

Structural loads were provided by Krivonen & Associates are not expected to exceed 22 kips at isolated columns and 2 to 3 kips per linear foot along continuous wall foundations for long-term loading conditions. Cuts and fills for building pad construction are anticipated to be typically on the order of 3 feet, and are not expected to exceed 4 feet. The site is currently occupied by BLM buildings and parking areas.

1.2 Purpose and Scope of Work

The purpose of this study is to evaluate the feasibility of the proposed development with respect to the observed subsurface conditions, and to provide our geotechnical recommendations and opinions as outlined in our proposal dated January 11, 2005, and summarized below.

• General soil and groundwater conditions at the project site, with emphasis on how the conditions are expected to affect the proposed construction;

• Suggested specifications for earthwork construction, including site preparation recommendations, a discussion of reuse of existing near surface soils as structural or non-structural fill, and a discussion of remedial earthwork recommendations, if warranted;

• Recommendations for temporary excavations and trench backfill;

05-117-01 Page 1 of 12 June 28, 2007

• Conventional shallow spread foundation design including soil bearing values, minimum footing depth, resistance to lateral loads and estimated settlements;

• Preliminary structural sections for asphalt concrete pavement;

• Concrete reactivity potential of site soils; and

• Subgrade preparation for slab-on-grade concrete

Our scope of services consisted of background review, site reconnaissance, field exploration, laboratory testing, engineering analyses, and preparation of this report. This study did not include evaluations of site seismicity, liquefaction, faulting, or other potential geologic or environmental hazards.

1.3 Authorization

Authorization to proceed with our work on this project was provided on March 17, 2005.

1.4 References

The following information was provided to Rimrock Engineering in the course of this study and serves as the basis of our understanding of the project type and scope.

• A preliminary site plan (not to scale) showing the proposed location of the building additions on the site. This drawing was the basis for the Site Map shown on Plate 2 of this report.

• NRCS 2004 DOQ – Miles City, Montana, Custer County. This map was the basis for the Vicinity Map shown on Plate 1 of this report.

2.0 METHODS OF STUDY

2.1 Field Exploration

Our selection of field exploration locations was based on the anticipated project layout and site access. The subsurface exploration consisted of eight (8) test borings in the proposed construction area using a drill rig equipped with hollow stem augers. Boring depths ranged from about 5 to 16 feet below the existing ground surface. Locations of the borings shown on the

05-117-01 Page 2 of 12 June 28, 2007

Site Map (Plate 2, Appendix A) were approximated by measuring from the existing buildings and parking areas shown on the site map. These locations should be considered accurate only to the degree implied by the method used.

Soil conditions encountered are presented on the boring logs which are included as Plates 3 through 10. A description of the Unified Soil Classification System used to identify the site soils and a boring log legend are presented on Plates 11 and 12 (Appendix A).

Rimrock Engineering personnel logged the soil conditions exposed in the borings and collected relatively undisturbed Shelby tube samples, and driven penetration samples for laboratory testing. Soil samples were obtained by driving a 2-inch ID, Standard Penetration Sampler, into the bottom of the boring. The number of blows required to drive the last 12 inches of an 18-inch drive with a 140 pound hammer dropping 30 inches is recorded as the blows per foot (Blow Count) on the boring logs. When the sampler was withdrawn from the boring, samples were removed, examined by the field engineer, labeled and sealed to preserve the natural moisture content for laboratory testing. After borings were completed, they were checked for groundwater and backfilled with excavated soil using the equipment at hand.

2.2 Laboratory Testing

Laboratory testing is useful for evaluating both index and engineering properties of soils.

Typical index tests evaluate soil moisture content, soil particle gradation and plasticity characteristics. We performed laboratory testing on selected soil samples to assess the following:

• Soil Classification (ASTM D422, D1140, and D4318)

• Unit Weight and Moisture Content (ASTM D2937 and D2216)

• Consolidation (ASTM D2435)

• CBR (ASTM 1883)

In addition, the following analytical tests were performed by Northern Analytical Laboratories.

• Soluble Sulfate Content

Individual laboratory test results can be found on the boring logs and on Plates 13 through 18, Appendix A, at the end of this report.

05-117-01 Page 3 of 12 June 28, 2007

3.0 DISCUSSION

3.1 Site Conditions

Access to the project site is provided by the Garryowen Road. The project is bordered by Highway 10 on the northeast and commercial properties on the remaining sides. The site is presently part of the BLM complex of buildings. The ground surface in the area of the proposed building appears to be generally level. A total relief of less than two feet is currently present at the entire project site. Drainage on the site consisted of natural infiltration and sheetflow to the northeast.

3.2 Subsurface Conditions

The following paragraphs summarize the results of our field exploration. The boring logs should be reviewed for a more detailed description of the subsurface conditions at the locations explored.

encountered lean clay and sandy silty clay down to depths ranging from 6 to 15 feet.

Below the fine grained soils we encountered dense gravel and sand at depths from 11 to 14.8 feet below the existing site grades. Groundwater was encountered in some of the borings at a depths ranging from 11 to 14 feet below site grades during our investigation. The lean clay encountered in our investigation is moderately

Groundwater was encountered in some of the borings at 11 to 14 feet during our exploration (April 2005). Fluctuations in the level of the groundwater and soil moisture conditions as noted in this report may occur due to variations in precipitation, land use, irrigation, and other factors.

3.3 Laboratory Test Results

Laboratory testing was performed as previously discussed in Section 2.2. The test data were evaluated in combination with our field exploration information to assess the engineering properties of the predominant soil types. Atterberg limits tests indicated the clay has a low plasticity, while the consolidation tests indicated a low to moderate compressibility and low swell potential. The sulfate content test results indicated that the soils have a negligible potential for concrete reactivity.

05-117-01 Page 4 of 12 June 28, 2007

3.4 Analytical Methods

Field and laboratory data are useful when combined with engineering fundamentals to assess specific behavior such as bearing capacity, settlement, and other design parameters. The following approaches were used in developing the conclusions and recommendations presented in subsequent sections of this report.

• Allowable bearing pressures were computed using Terzaghi’s general bearing capacity formula.

• Settlements were computed using classical consolidation theory where saturated, fine-grained soils were present.

• Pavement sections were developed using the AASHTO pavement design procedure.

4.0 CONCLUSIONS

The following conclusions are based on the data collected during this assessment and are subject to the limitations stated in this report. These conclusions may change if additional information becomes available. Based on the results of our study, no severe soil or groundwater constraints were observed which would preclude development. The following is a summary of our conclusions.

encountered lean clay and sandy silty clay down to depths ranging from 6 to 15 feet.

Below the fine grained soils we encountered dense gravel and sand at depths from 11 to 14.8 feet below the existing site grades. Groundwater was encountered in some of the borings at a depths ranging from 11 to 14 feet below site grades during our investigation. The lean clay encountered in our investigation is moderately

• Conventional spread and continuous footings may be utilized to support structural loads. Foundations designed and constructed in accordance with the recommendations of this geotechnical report will require over-excavation and replacement with structural fill.

05-117-01 Page 5 of 12 June 28, 2007

Specific recommendations for project design and construction including mitigation of potential problems described above are presented in Section 5.0.

5.0 RECOMMENDATIONS

5.1 Site Clearing and Preparation

Prior to construction, surface vegetation and organic soils should be stripped and removed from the site or stockpiled for use in non-structural areas. It appears about 6 inches can be used as a reasonable estimate for average depth of stripping. Deeper stripping/grubbing of organic soils, tree roots, etc., may be required in localized areas. Tree root balls should be removed and the resulting voids backfilled with adequately compacted backfill soil. All man-made debris including dumped fills or trash should be removed from the site. The geotechnical engineer should be present during stripping and site preparation operations to observe stripping and grubbing depths, and to evaluate whether buried obstacles such as underground utilities, wells, and foundations are present. Excavations resulting from removal operations should be cleaned of all loose material and widened as necessary to permit access to compaction equipment.

5.2 Earthwork

5.2.1 General Site Grading

Site preparation and grading should conform to the requirements contained in this report and in the suggested specifications which are provided as Appendix B of this report. We anticipate that site grading can be performed with conventional earthmoving equipment. Prior to fill placement, the exposed native soils should be scarified to a minimum depth of six inches, moisture conditioned as necessary, and compacted to a minimum of 95% relative compaction in accordance with the ASTM D698 compaction test method.

Where fill is necessary, materials should meet the gradation and plasticity requirements listed for “structural fill” in Appendix B. The existing site soils are not capable of meeting recommended requirements for structural fill. Fill placement and compaction requirements presented in Appendix B should be followed.

The near surface soils appear to be stiff and at a low enough moisture content that pumping of subgrade soils under equipment loading should not be a problem. If the subgrade should become wet, or excavations extend to near the groundwater level, soft and pumping subgrade conditions could be experienced. This might require the use of a geotextile for stabilization, the use of small equipment, or other methods to prevent pumping.

05-117-01 Page 6 of 12 June 28, 2007

5.2.2 Temporary Unconfined Excavations

The contractor is ultimately responsible for the safety of workers and should strictly observe federal and local OSHA requirements for excavation shoring and safety. All temporary slopes should comply with OSHA requirements for Type A soils. During wet weather, runoff water should be prevented from entering excavations.

5.2.3 Temporary Trench Excavation and Backfill

It appears that excavation for footings and utility trenches can be readily made with either a conventional backhoe or excavator in the native soil. We expect the walls of the footing trenches to stand near vertically in the on-site soils without significant sloughing. If trenches are extended deeper than five feet or are allowed to dry out, the excavations may become unstable and should be evaluated to verify their stability prior to occupation by construction personnel.

Shoring or sloping of any deep trench walls may be necessary to protect personnel and provide temporary stability. All excavations should comply with current OSHA safety requirements for Type A soils. (Federal Register 29 CFR, Part 1926).

Backfills for trenches or other excavations within pavement areas, beneath slabs, and adjacent to foundations should be compacted in six to eight inch layers with mechanical tampers. Jetting and flooding should not be permitted. We recommend all backfill be compacted to a minimum compaction of 97% of the maximum dry density as determined by ASTM D698. The moisture content of compacted backfill soils should be within 2% of the optimum. Poor compaction in utility trench backfill may cause excessive settlements resulting in damage to the pavement structural section or other overlying improvements. Compaction of trench backfill outside of improvement areas should be a minimum of 90% relative compaction

5.3 Foundations

Alternative foundation systems were not considered, since spread footing foundations bearing on over-excavated and re-compacted structural fill can be used. Exterior continuous footings and interior column footings should be over-excavated 2 feet in depth and extend laterally 2 feet beyond the edge of the foundation. Utilizing the structural loads provided in Section 1.1, and an allowable bearing pressure of 1,500 pounds per square foot, a settlement of ¾ to 1 inch was estimated.

Due to the underlying soft clay soils, it is recommended that the structural fill be reinforced with geogrid placed at mid height in the structural fill for the isolated column foundations only. The MSE (mechanically stabilized earth) footings should contain a layer of Tensar Biaxial Geogrid BX 1300 or equivalent. The geogrid should be placed according to manufacturers recommendations.

05-117-01 Page 7 of 12 June 28, 2007

Exterior foundations should be embedded a minimum of 3.5 feet below lowest adjacent exterior finish grade for frost protection and confinement. Interior footings should be bottomed at least 12 inches below lowest adjacent finish grade for confinement. Wall foundation dimensions should satisfy the requirements listed in the latest edition of the International Building Code.

Reinforcing steel requirements for foundations should be provided by the design engineer.

The allowable bearing pressures, indicated above, are net values, therefore, the weight of the foundation and backfill may be neglected when computing dead loads. Allowable bearing pressures may be increased by one-third for short-term loading such as wind or seismic.

Resistance to lateral loads may be calculated using an allowable passive equivalent fluid unit weight of 180 pounds per cubic foot and an allowable coefficient of friction of 0.31 applied to vertical dead loads. Both passive and frictional resistances may be assumed to act concurrently. An active fluid pressure of 40 pounds per cubic foot may be used.

5.4 Concrete Slab-on-Grade Construction

Prior to constructing concrete slabs, the upper six inches of slab subgrade should be scarified, moisture conditioned to within 2% of optimum, and uniformly compacted to at least 95% of maximum dry density as determined by ASTM D698. Scarification and compaction will not be required if floor slabs are to be placed directly on undisturbed compacted structural fill.

All concrete floor slabs should have a minimum thickness of four inches. Slab thickness and structural reinforcing requirements within the slab should be determined by the design engineer.

At least four inches of crushed base aggregate should be placed beneath slab-on-grade floors to provide uniform support. The aggregate base should be compacted to a minimum of 95% relative compaction.

We recommend that the base course be placed within three to five days (depending on the time of year) after moisture conditioning and compaction of the subgrade soil. The subgrade should be protected against drying until the concrete slab is placed.

In floor slab areas where moisture sensitive floor coverings are planned, an impermeable membrane (e.g. 10-mil thick polyethylene) should be placed over the base course to reduce the migration of moisture vapor through the concrete slabs. The impermeable membrane should be protected by two inches of fine, moist sand placed both above and below the membrane. The sand cover will provide protection for the membrane and will promote uniform curing of the concrete slab. The sand cover should be moistened and tamped prior to slab placement.

5.5 Pavement Sections

The recommended pavement structural sections for the project presented in Table 1 were calculated using the AASHTO pavement design procedure. Traffic loading information was not available at the issue of this report. If traffic loading information becomes available or if loading is anticipated to exceed assumed loading conditions, alternative pavement structural sections

05-117-01 Page 8 of 12 June 28, 2007 should be determined based on the provided loading information. In our analysis, we have assumed a light duty traffic loading conditions of 65,700 18-kip ESAL for the lifetime of the pavement. A CBR value of 4.8 was used for design of the pavement sections.

TABLE 1

PAVEMENT STRUCTURAL SECTIONS

Traffic Condition Recommended Minimum Structural Section* Light Duty Section 3 inches Asphaltic Concrete, 8-inch Base Course

* Aggregate base course thickness may be reduced in each pavement structural section by approximately 20% with the use of a recommended geotextile fabric.

Placement and compaction procedures for materials and construction should conform to the suggested specifications contained in Appendix B of this report. The sections presented in Table 1 are based on CBR tests performed on selected samples obtained during our investigation and should be considered preliminary in nature. We recommend verification of soil conditions as construction progresses so that appropriate revisions can be made if necessary.

Aggregate base course thickness may be reduced in each alternate pavement structural section by approximately 20% with the use of Amoco 4553 or 2002 geotextile fabric or comparable geotextile fabric meeting AASHTO M 288-2000 class 1 requirements. If this alternative is selected, we can provide addition pavement structural sections.

The asphalt pavement structural sections presented in Table 1 are designed for the assumed traffic loadings. However, based on our experience in the area, environmental aspects such as freeze-thaw cycles and thermal cracking will probably govern the life of AC pavements in light traffic areas. Thermal cracking of the asphalt pavements allows more water to enter the pavement section which promotes deterioration and increases maintenance costs.

It should be noted that the subgrade soils are likely to be prone to frost action during the winter and saturation during the wet spring months. The primary impact of frost action and subgrade saturation is the loss of subgrade and aggregate base strength. Pavement life will be increased if efforts are made to reduce the accumulation of excess moisture in the subgrade soils.

Consideration should be given to installing subdrainage in the form of trench drains in low areas, which are daylighted or tied to the storm drain system.

5.6 Site Drainage

Final elevations at the site should be planned so that drainage is directed away from all foundations. Parking areas should be sloped and drainage gradients maintained to carry all surface water off the site. In parking lot areas, curbs adjacent to landscaping should be deepened to act as a cutoff, or a sub-drain system should be constructed to collect excessive water from landscaping irrigation.

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5.7 Soil Reactivity

Analytical testing of selected soil samples was performed to assess the potential for adverse reactivity with concrete. Soluble sulfate tests were performed to evaluate potential sulfate attack against Portland Cement Concrete. Soluble sulfate contents were observed to be less than 0.07%. Therefore, the potential for sulfate attack appears to be negligible and conventional Type II cement may be used according to Table 1904.3 of the 2000 International Building Code.

6.0 ADDITIONAL SERVICES

6.1 Project Bid Documents

It has been our experience during the bidding process, that contractors often contact us to discuss the geotechnical aspects of the project. Informal contacts between Rimrock Engineering and an individual contractor could result in incorrect or incomplete information being provided to the contractor. Therefore, we recommend a pre-bid meeting be held to answer any questions about the report prior to submittal of bids. If this is not possible, questions or clarifications regarding this report should be directed to the project Owner or his designated representative. After consultation with Rimrock Engineering, the project Owner (or his representative) should provide clarifications or additional information to all contractors bidding the job.

6.2 Construction Observation/Testing and Plan Review

The recommendations made in this report are based on the assumption that an adequate program of tests and observations will be made during construction to verify compliance with these recommendations. These tests and observations should include, but not necessarily be limited to, the following:

• Observations and testing during site preparation and earthwork.

• Observation of footing trench excavations.

• Observation and testing of construction materials.

• Consultation as may be required during construction.

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We also recommend that project plans and specifications be reviewed by us to verify compatibility with our conclusions and recommendations. Additional information concerning the scope and cost of these services can be obtained from our office.

The review of plans and specifications and the field observation and testing by Rimrock Engineering are an integral part of the conclusions and recommendations made in this report. If we are not retained for these services, the Client agrees to assume Rimrock Engineering’s responsibility for any potential claims that may arise during construction.

7.0 LIMITATIONS

Recommendations contained in this report are based on our field explorations, laboratory tests, and our understanding of the proposed construction. The study was performed using a mutually agreed upon scope of work. It is our opinion that this study was a cost-effective method to evaluate the subject site and evaluate some of the potential geotechnical concerns. More detailed, focused, and/or thorough investigations can be conducted. Further studies will tend to increase the level of assurance, however, such efforts will result in increased costs. If the Client wishes to reduce the uncertainties beyond the level associated with this study, Rimrock Engineering should be contacted for additional consultation.

The soils data used in the preparation of this report were obtained from borings made for this investigation. It is possible that variations in soils exist between the points explored. The nature and extent of soil variations may not be evident until construction occurs. If any soil conditions are encountered at this site which are different from those described in this report, our firm should be immediately notified so that we may make any necessary revisions to our recommendations. In addition, if the scope of the proposed project, locations of structures, or building loads change from the description given in this report, our firm should be notified.

This report has been prepared for design purposes for specific application to the BLM Building Additions project in accordance with the generally accepted standards of practice at the time the report was written. No warranty, express or implied, is made.

Other standards or documents referenced in any given standard cited in this report, or otherwise relied upon by the authors of this report, are only mentioned in the given standard; they are not incorporated into it or “included by reference,” as that latter term is used relative to contracts or other matters of law.

This report may be used only by the Client and for the purposes stated, within a reasonable time from its issuance. Land use, site conditions (both on- and off-site), or other factors including

05-117-01 Page 11 of 12 June 28, 2007 advances in man’s understanding of applied science may change over time and could materially affect our findings. Therefore, this report should not be relied upon after 36 months from its issue. Rimrock Engineering should be notified if the project is delayed by more than 24 months from the date of this report so that a review of site conditions can be made, and recommendations revised if appropriate.

It is the Client’s responsibility to see that all parties to the project including the designer, contractor, subcontractors, etc., are made aware of this report in its entirety. The use of information contained in this report for bidding purposes should be done at the Contractor’s option and risk. Any party other than the Client who wishes to use this report shall notify Rimrock Engineering of such intended use by executing the “Application for Authorization to Use” which follows this document as an appendix. Based on the intended use of the report, Rimrock Engineering 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 Rimrock Engineering from any liability resulting from the use of this report by any unauthorized party.

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APPENDIX B

SUGGESTED SPECIFICATIONS FOR

EARTHWORK AND PAVEMENT CONSTRUCTION

BLM BUILDING ADDITIONS

BILLINGS, MONTANA

1.0 GENERAL

1.1 Scope - The work done under these specifications shall include clearing, stripping, removal of unsuitable material, excavation, preparation of natural soils, placement and compaction of on-site and imported structural fill material, and placement and compaction of pavement materials.

1.2 Contractor's Responsibility - A geotechnical investigation was performed for the project by Rimrock Engineering dated April 20, 2005. The Contractor shall attentively examine the site in such a manner that he can confirm existing surface conditions with those presented in the geotechnical report. He shall satisfy himself that the quality and quantity of exposed materials and subsurface soil or rock deposits have been satisfactory represented by the Geotechnical Engineer's report and Civil Engineer's drawings. Any discrepancy that may be of prior knowledge to the Contractor or that is revealed through his investigations shall be made available to the Owner. It is the Contractor’s responsibility to review the attached report prior to construction. The selection of equipment for use on the project and the order of work will similarly be his responsibility such that the requirements included in following sections have been met.

1.3 Geotechnical Engineer - The work covered by these specifications shall be observed and tested by the Geotechnical Engineer, Rimrock Engineering, who shall be hired by the Owner. The Geotechnical Engineer will be present during the site preparation and grading to observe the work and to perform the tests necessary to evaluate material quality and compaction. The Geotechnical Engineer shall submit a report to the Owner, including a tabulation of all tests performed. The costs of retesting of unsuitable work performed by the Contractor shall be deducted from the payments to the Contractor.

1.4 Standard Specifications - Where referred to in these specifications, “Standard

Specifications” shall mean the current Montana Public Works Standard Specifications dated March 2003.

1.5 Compaction Test Method - Where referred to herein, relative compaction shall mean the in-place dry density of soil expressed as a percentage of the maximum

Rimrock Engineering, Inc. Page 1 of 5 April 20, 2005 dry density of the same material, as determined by ASTM D698 Compaction Test Procedure. Optimum moisture content shall mean the moisture content at maximum dry density as determined above.

2.0 SITE PREPARATION

2.1 Clearing - Areas to be graded shall be cleared and grubbed of all vegetation and debris. These materials shall be removed from the site by the Contractor.

2.2 Stripping - Surface soils containing roots and organic matter shall be stripped from areas to be graded and stockpiled or discarded as directed by the Owner.

In general, the depth of stripping of the topsoil will be approximately six inches.

Deeper stripping, where required to remove weak soils or accumulations or organic matter, shall be performed when determined by the Geotechnical Engineer. Strippings shall be removed from the site or stockpiled at a location designated by the Owner.

2.3 Removal of Existing Fill - Existing fill soils, trash, and debris in the areas to be graded shall be removed prior to the placing of any compacted fill. Portions of any existing fills that are suitable for use in compacted fill may be stockpiled for future use. All organic material, topsoil, expansive soils, oversize material or other unsuitable material shall be removed from the site by the Contractor or disposed of at a location on site, if so designated by the Owner.

2.4 Ground Surface - The ground surface exposed by stripping shall be scarified to a depth of six inches, moisture conditioned to the proper moisture content for compaction, and compacted as required for compacted fill. Recompaction shall be approved by the Geotechnical Engineer prior to placing fill.

3.0 EXCAVATION

3.1 General - Excavations shall be performed to the lines and grades indicated on the plans. The data presented in the geotechnical investigation report is for information and only the Contractor shall make his own interpretation with regard to the methods and equipment necessary to perform the excavation and to obtain material suitable for fill.

3.2 Materials - Soils which are removed and are unsuitable for fill should be placed in non-structural areas of the project. When necessary, these soils may be placed in deeper fills if approved by the Geotechnical Engineer.

3.3 Treatment of Exposed Surface - The ground surface exposed by excavation shall be scarified to a depth of six inches, moisture conditioned to the proper moisture content for compaction, and compacted as required for compacted fill.

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Recompaction shall be approved by the Geotechnical Engineer prior to placing fill.

4.0 STRUCTURAL FILL

4.1 Limits – Structural fill will be used for fill beneath foundations for exterior continuous footings and interior column footings. In this area, the existing clay will be over excavated by at least 2 feet below the bottom of footings, and laterally 2 feet beyond the edge of footings, and replaced with structural fill.

4.2 Material – Structural fill material shall consist of medium dense to dense gravels.

In areas containing soft lean clay, the spread and continuous footings shall be placed on a gravel pad a minimum of two feet below foundation bottom and extending two feet beyond the perimeter of the footings. We recommend the gradation for structural fill be 100% passing the 3-inch sieve, 25 to 65% passing the No. 4 sieve, and no more than 20% minus No. 200 sized material. The structural fill should have a liquid limit less than 25 and a plasticity index less than 15.

4.3 Placement - All fill materials shall be placed in layers of eight inches or less in loose thickness and uniformly moisture conditioned. The lift should then be compacted with approved compaction equipment to achieve at least 95% relative compaction in areas under structures, utilities, roadways, parking areas, and to at least 90% in undeveloped areas. No fill material shall be placed, spread, or rolled while it is frozen or thawing, or during unfavorable weather conditions.

4.4 Benching - Fill placed on slopes steeper than 5 horizontal to 1 vertical shall be keyed into firm, native soils or rock by a series of benches. Benching can be conducted simultaneously with placement of fill. However, the method and extent of benching shall be checked by the Geotechnical Engineer.

4.5 Compaction Equipment - The Contractor shall provide and use sufficient equipment of a type and weight suitable for the conditions encountered in the field. The equipment shall be capable of obtaining the required compaction in all areas, including those that are inaccessible to ordinary rolling equipment.

4.6 Recompaction - When, in the judgment of the Geotechnical Engineer, sufficient compaction effort has not been used, or where the field density tests indicate that the required compaction or moisture content has not been obtained, or if “pumping” or other indications of instability are noted, the fill shall be reworked and recompacted as needed to obtain a stable fill at the required density and moisture content prior to placing additional fill materials.

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4.7 Responsibility - The Contractor shall be responsible for the maintenance and protection of all embankments and fills made during the contract period and shall bear the expense of replacing any portion which has become displaced due to carelessness, negligent work, or failure to take proper precautions.

5.0 UTILITY TRENCH BEDDING AND BACKFILL

5.1 Material - Pipe bedding shall be defined as all material within six inches of the perimeter of the pipe. Backfill shall be classified as all material within the remainder of the trench. Material for use as bedding shall consist of clean, granular materials, and shall conform to requirements for bedding material listed in Section 02221 of the Standard Specifications.

5.2 Placement and Compaction - Pipe bedding shall be placed in thin layers not exceeding eight inches in loose thickness, and conditioned to the proper moisture content for compaction.

All other trench backfill shall be placed in thin layers not exceeding…