312011 - Earthwork.pdf

Project No. 438-22-900 Addendum 3 – January 17, 2025 Replace Boiler Plant

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SECTION 31 20 11

EARTHWORK (SHORT FORM)

PART 1 - GENERAL

1.1:DESCRIPTION:

This section specifies the requirements for furnishing all equipment, materials, labor and techniques for earthwork including excavation, fill, backfill and site restoration utilizing fertilizer, seed and/or sod.

1.2 DEFINITIONS:

A. Unsuitable Materials:

1. Fills: Topsoil, frozen materials; construction materials and materials subject to decomposition; clods of clay and stones larger than 75 mm (3 inches); organic materials, including silts, which are unstable; and inorganic materials, including silts, too wet to be stable.

2. Existing Subgrade (except footings): Same materials as above paragraph, that are not capable of direct support of slabs, pavement, and similar items, with the possible exception of improvement by compaction, proof rolling, or similar methods of improvement.

3. Existing Subgrade (footings only): Same as Paragraph 1, but no fill or backfill. If materials differ from reference borings and design requirements, excavate to acceptable strata subject to COR's approval.

B. Earthwork: Earthwork operations required within the new construction area. It also includes earthwork required for auxiliary structures and buildings and sewer and other trenchwork throughout the job site.

C. Degree of Compaction: Degree of compaction is expressed as a percentage of maximum density obtained by test procedures. Refer to Geotechnical report prepared by Geotek Engineering & Testing Services, Inc, dated

June 9, 2023 (herein referred to as “Geotechnical Report”) and included with this specification.

D. The term fill means fill or backfill as appropriate.

1.3 RELATED WORK:

A. Materials testing and inspection during construction: Section 01 45 29, TESTING LABORATORY SERVICES.

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B. Safety Requirements: Section 00 72 00, GENERAL CONDITIONS, Article, ACCIDENT PREVENTION.

C. Protection of existing utilities, fire protection services, existing equipment, roads, and pavements: Section 01 00 00, GENERAL

REQUIREMENTS.

D. Subsurface Investigation: Section 01 00 00, GENERAL REQUIREMENTS, Article, PHYSICAL DATA.

E.

1.4 CLASSIFICATION OF EXCAVATION:

A. Unclassified Excavation: Removal and disposal of pavements and other man-made obstructions visible on the surface; utilities, and other items including underground structures indicated to be demolished and removed; together with any type of materials regardless of character of material and obstructions encountered.

B. Classified Excavation: Removal and disposal of all material not defined as rock.

C. Rock Excavation:

1. Solid ledge rock (igneous, metamorphic, and sedimentary rock).

2. Bedded or conglomerate deposits so cemented as to present characteristics of solid rock which cannot be excavated without blasting; or the use of a modern power excavator (shovel, backhoe, or similar power excavators) of no less than 0.75 m3 (1 cubic yard) capacity, properly used, having adequate power and in good running condition.

3. Boulders or other detached stones each having a volume of 0.4 m3

(1/2 cubic yard) or more.

1.7 SUBMITTALS:

A. Submit in accordance with Section 01 33 23, SHOP DRAWINGS, PRODUCT

DATA, AND SAMPLES.

B. Contractor shall submit procedure and location for disposal of unused satisfactory material. Proposed source of borrow material. Notification of encountering rock in the project. Advance notice on the opening of excavation or borrow areas. Advance notice on shoulder construction for rigid pavements.

C. Furnish to COR results of soil laboratory tests results of proposed off site or on site fill material.

D. Qualifications of the commercial testing laboratory shall be submitted.

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1.8 APPLICABLE PUBLICATIONS:

A. Publications listed below form a part of this specification to the extent referenced. Publications are referenced in the text by the basic designation only.

B. American Nursery and Landscape Association (ANLA):

2004....................American Standard for Nursery Stock

C. American Association of State Highway and Transportation Officials

(AASHTO):

T99-10..................Moisture-Density Relations of Soils Using a 2.5 kg (5.5 lb) Rammer and a 305 mm (12 inch) Drop

T180-10.................Standard Method of Test for Moisture-Density

Relations of Soils Using a 4.54-kg [10 lb]

Rammer and a 457 mm (18 inch) Drop

D. American Society for Testing and Materials (ASTM):

C33-03..................Concrete Aggregate

D698-e1.................Laboratory Compaction Characteristics of Soil

Using Standard Effort

D1140-00................Amount of Material in Soils Finer than the No.

200 (75-micrometer) Sieve

D1556-00................Standard Test Method for Density and Unit

Weight of Soil in Place by the Sand-Cone Method

D1557-09................Laboratory Compaction Characteristics of Soil

Using Modified Effort

D2167-94 (2001).........Standard Test Method for Density and Unit

Weight of Soil in Place by the Rubber Balloon

Method

D2487-06................Standard Classification of Soil for Engineering

Purposes (Unified Soil Classification System)

D6938-10................Standard Test Methods for Density of Soil and

Soil-Aggregate in Place by Nuclear Methods

(Shallow Depth)

E. Standard Specifications of State of South Dakota Department of

Transportation, latest revision.

PART 2 - PRODUCTS

2.1 MATERIALS:

A. As defined in the Geotechnical report prepared by Geotek Engineering &

Testing Services, Inc, dated June 9, 2023 (herein referred to as

“Geotechnical Report”) and included with this specification.

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B. Fills: Materials approved from on site and off site sources having a minimum dry density of 1760 kg/m3 (110 pcf), a maximum Plasticity Index of 6, and a maximum Liquid Limit of 30.

C. Granular Fill:

1. Under concrete slab, granular fill shall consist of clean, poorly graded crushed rock, crushed gravel, or uncrushed gravel placed beneath a building slab with or without a vapor barrier to cut off the capillary flow of pore water to the area immediately below.

Fine aggregate grading shall conform to ASTM C33 with a maximum of 3 percent by weight passing ASTM D1140.

2. Bedding for sanitary and storm sewer pipe, crushed stone or gravel graded from 13 mm (1/2 inch) to 4.75 mm (No. 4).

D. Fertilizer: (5-10-5) delivered to site in unopened containers that clearly display the manufacturer's label, indicating the analysis of the contents.

E. Seed: Grass mixture comparable to existing turf delivered to site in unopened containers that clearly display the manufacturer's label, indicating the analysis of the contents.

F. Sod: Comparable species with existing turf. Use State Certified or

State Approved sod when available. Deliver sod to site immediately after cutting and in a moist condition. Thickness of cut must be 19 mm to 32 mm (3/4 inch to 1 1/4 inches) excluding top growth. There shall be no broken pads and torn or uneven ends.

G. Requirements For Offsite Soils: Offsite soils brought in for use as backfill shall be tested for TPH, BTEX and full TCLP including ignitability, corrosivity and reactivity. Backfill shall contain less than 100 parts per million (ppm) of total hydrocarbons (TPH) and less than 10 ppm of the sum of Benzene, Toluene, Ethyl Benzene, and Xylene

(BTEX)and shall not fail the TCLP test. TPH concentrations shall be determined by using EPA 600/4-79/020 Method 418.1. BTEX concentrations shall be determined by using EPA SW-846.3-3a Method5030/8020. TCLP shall be performed in accordance with EPA SW-846.3-3a Method 1311.

Provide Borrow Site Testing for TPH, BTEX and TCLP from a composite sample of material from the borrow site, with at least one test from each borrow site. Material shall not be brought on site until tests have been approved by the COR.

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H. Buried Warning and Identification Tape: Polyethylene plastic and metallic core or metallic-faced, acid- and alkali-resistant polyethylene plastic warning tape manufactured specifically for warning and identification of buried utility lines. Provide tape on rolls, 3 inch minimum width, color coded as specific below for the intended utility with warning and identification imprinted in bold black letters continuously over the entire tape length. Warning and identification to read, “CAUTION, BURIED (intended service) LINE BELOW” or similar wording. Color and printing shall be permanent, Unaffected by moisture or soil. Warning tape color codes:

Red: Electric

Yellow: Gas, Oil, Dangerous Materials

Orange: Telephone and Other Communications

Blue: Water Systems

Green: Sewer Systems

White: Steam Systems

Gray: Compressed Air

I. Warning Tape for Metallic Piping: Acid and alkali-resistant polyethylene plastic tape conforming to the width, color, and printing requirements specified above. Minimum thickness of tape shall be 0.076 mm (0.003 inch). Tape shall have a minimum strength of 10.3 MPa (1500 psi) lengthwise, and 8.6 MPa (1250 psi) crosswise, with a maximum 350 percent elongation.

J. Detectable Warning Tape for Non-Metallic Piping: Polyethylene plastic tape conforming to the width, color, and printing requirements specified above. Minimum thickness of the tape shall be 0.102 mm

(0.004 inch). Tape shall have a minimum strength of 10.3 MPa (1500 psi) lengthwise and 8.6 MPa (1250 psi) crosswise. Tape shall be manufactured with integral wires, foil backing, or other means of enabling detection by a metal detector when tape is buried up to 0.9 m(3 feet) deep. Encase metallic element of the tape in a protective jacket or provide with other means of corrosion protection.

K. Detection Wire For Non-Metallic Piping: Detection wire shall be

Insulated single strand, solid copper with a minimum of 12 AWG.

PART 3 - EXECUTION

3.1 SITE PREPARATION:

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A. Clearing: Clearing within the limits of earthwork operations as described or designated by the COR. Work includes removal of trees, shrubs, fences, foundations, incidental structures, paving, debris, trash and any other obstructions. Remove materials from the Medical

Center.

B. Grubbing: Remove stumps and roots 75 mm (3 inches) and larger diameter.

Undisturbed sound stumps, roots up to 75 mm (3 inches) diameter, and nonperishable solid objects which will be a minimum of 900 mm (3 feet) below subgrade or finished embankment may be left.

C. Trees and Shrubs: Trees and shrubs, not shown for removal, may be removed from the areas within 4500 mm (15 feet) of new construction and

2250 mm (7’-6”) of utility lines if such removal is approved in advance by the COR. Remove materials from the Medical Center. Trees and shrubs, shown to be transplanted, shall be dug with a ball of earth and burlap wrapped in accordance with the latest issue of the, "American Standard for Nursery Stock", of the American Association of Nurserymen, Inc.

Transplant trees and shrubs to a permanent or temporary position within two hours after digging. Maintain trees and shrubs held in temporary locations by watering as necessary and feeding semi-annually with liquid fertilizer with a minimum analysis of 5 percent nitrogen, 10 percent phosphorus and 5 percent potash. Maintain plants moved to permanent positions as specified for plants in temporary locations until the conclusion of the contract. Protect from damage, existing trees and shrubs which are not shown to be removed in the construction area. Repair immediately damage to existing trees and shrubs by trimming, cleaning and painting damaged areas, including the roots, in accordance with standard industry horticultural practice for the geographic area and plant species. Building materials shall not be stored closer to trees and shrubs that are to remain, than the farthest extension of their limbs.

D. Stripping Topsoil: Unless otherwise indicated on the drawings, the limits of earthwork operations shall extend anywhere the existing grade is filled or cut or where construction operations have compacted or otherwise disturbed the existing grade or turf. Strip topsoil as defined herein, or as indicated in the geotechnical report, from within the limits of earthwork operations as specified above unless specifically indicated or specified elsewhere in the specifications or shown on the drawings. Topsoil shall be fertile, friable, natural

31 20 11 - 7 topsoil of loamy character and characteristic of the locality. Topsoil shall be capable of growing healthy horticultural crops of grasses.

Stockpile topsoil and protect as directed by the COR. Eliminate foreign material, such as weeds, roots, stones, subsoil, frozen clods, and similar foreign materials, larger than 0.014 m3 (1/2 cubic foot) in volume, from soil as it is stockpiled. Retain topsoil on the station.

Remove foreign materials larger than 50 mm (2 inches) in any dimension from topsoil used in final grading. Topsoil work, such as stripping, stockpiling, and similar topsoil work, shall not, under any circumstances, be carried out when the soil is wet so that the tilth of the soil will be destroyed.

1. Concrete Slabs and Paving: Score deeply or saw cut to insure a neat, straight cut, sections of existing concrete slabs and paving to be removed where excavation or trenching occurs. Extend pavement section to be removed a minimum of 300 mm (12 inches) on each side of widest part of trench excavation and insure final score lines are approximately parallel unless otherwise indicated. Remove material from the Medical Center.

E. Disposal: All materials removed from the property shall be disposed of at a legally approved site, for the specific materials, and all removals shall be in accordance with all applicable Federal, State and local regulations. No burning of materials is permitted onsite.

3.2 EXCAVATION:

A. Shoring, Sheeting and Bracing: Shore, brace, or slope to the angle of repose banks of excavations to protect workmen, banks, adjacent paving, structures, and utilities, in compliance with OSHA requirements.

1. Extend shoring and bracing to the bottom of the excavation. Shore excavations that are carried below the elevations of adjacent existing foundations.

2. If the bearing of any foundation is disturbed by excavating, improper shoring or removal of shoring, placing of backfill, and similar operations, provide a concrete fill support in compliance with Specification Section 31 23 23.33, FLOWABLE FILL, under disturbed foundations, as directed by COR, at no additional cost to the Government. Do not remove shoring until permanent work in excavation has been inspected and approved by COR.

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B. Excavation Drainage: Operate pumping equipment, and/or provide other materials, means and equipment as required, to keep excavations free of water and subgrades dry, firm, and undisturbed until approval of permanent work has been received from COR. Approval by the COR is also required before placement of the permanent work on all subgrades. When subgrade for foundations has been disturbed by water, remove the disturbed material to firm undisturbed material after the water is brought under control. Replace disturbed subgrade in trenches by mechanically tamped sand or gravel. When removed disturbed material is located where it is not possible to install and properly compact disturbed subgrade material with mechanically compacted sand or gravel, the COR should be contacted to consider the use of flowable fill.

Groundwater flowing toward or into excavations shall be controlled to prevent sloughing of excavation slopes and walls, boils, uplift and heave in the excavation and to eliminate interference with orderly progress of construction. French drains, sumps, ditches or trenches will not be permitted within 0.9 m (3 feet) of the foundation of any structure, except with specific written approval, and after specific contractual provisions for restoration of the foundation area have been made. Control measures shall be taken by the time the excavation reaches the water level in order to maintain the integrity of the in-situ material. While the excavation is open, the water level shall be maintained continuously, at least 3 feet below the working level.

Operate dewatering system continuously until construction work below existing water levels is complete. Submit performance records weekly.

Measure and record performance of dewatering system at same time each day by use of observation wells or piezometers installed in conjunction with the dewatering system. Relieve hydrostatic head in pervious zones below subgrade elevation in layered soils to prevent uplift, if applicable.

C. Blasting: Blasting shall not be permitted.

D. Building Earthwork:

1. Excavation shall be accomplished as required by drawings, specifications, and the Geotechnical Report.

2. Excavate foundation excavations to solid undisturbed subgrade.

3. Remove loose or soft material to the elevations shown for foundation installation.

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4. Fill excess cut under footings or foundations with structural fill.

Refer to Geotechnical Report.

3. Do not tamp earth for backfilling in footing bottoms, except as specified.

E. Trench Earthwork:

1. Utility trenches (except sanitary and storm sewer):

a. Excavate to a width as necessary for sheeting and bracing and proper performance of the work.

b. Grade bottom of trenches with bell-holes, scooped-out to provide a uniform bearing.

c. Support piping on suitable undisturbed earth unless a mechanical support is shown. Unstable material removed from the bottom of the trench or excavation shall be replaced with select granular material placed in layers not exceeding 150 mm (6 inches) loose thickness.

d. The length of open trench in advance of pipe laying shall not be greater than is authorized by the COR.

e. Provide buried utility lines with utility identification tape.

Bury tape 300 mm (12 inches) below finished grade; under pavements and slabs, bury tape 150 mm (6 inches) below top of subgrade.

f. Bury detection wire directly above non-metallic piping at a distance not to exceed 300 mm (12 inches) above the top of pipe.

The wire shall extend continuously and unbroken, from manhole to manhole. The ends of the wire shall terminate inside the manholes at each end of the pipe, with a minimum of 0.9 m (3 feet) of wire, coiled, remaining accessible in each manhole. The wire shall remain insulated over its entire length. The wire shall enter manholes between the top of the corbel and the frame, and extend up through the chimney seal between the frame and the chimney seal. For force mains, the wire shall terminate in the valve pit at the pump station end of the pipe.

g. Bedding shall be of the type and thickness show. Initial backfill material shall be placed and compacted with approved tampers to a height of at least one foot above the utility pipe or conduit. The backfill shall be brought up evenly on both sides of the pipe for the full length of the pipe. Care shall be taken to ensure thorough compaction of the fill under the

31 20 11 - 10 haunches of the pipe. Except as specified otherwise in the individual piping section, provide bedding for buried piping in accordance with AWWA C600, Type 4, except as specified herein.

Backfill to top of pipe shall be compacted to 95 percent of ASTM

D 698maximum density. Plastic piping shall have bedding to spring line of pipe. Provide materials as follows:

1) Refer to Geotechnical Report: Angular, 6 to 40 mm (0.25 to 1.5 inches), graded stone, including a number of fill materials that have regional significance such as coral, slag, cinders, crushed stone, and crushed shells.

2) Refer to Geotechnical Report: Coarse sands and gravels with maximum particle size of 40 mm (1.5 inches), including various graded sands and gravels containing small percentages of fines, generally granular and non-cohesive, either wet or dry.

Soil Types GW, GP, SW, and SP are included in this class as specified in ASTM D 2487.

2. Sanitary and storm sewer trenches:

a. Trench width below a point 150 mm (6 inches) above top of the pipe shall be 600 mm (24 inches) for up to and including 300 mm

(12 inches) diameter and four-thirds diameter of pipe plus 200 mm

(8 inches) for pipe larger than 300 mm (l2 inches). Width of trench above that level shall be as necessary for sheeting and bracing and proper performance of the work.

b. The bottom quadrant of the pipe shall be bedded on suitable undisturbed soil or granular fill. Unstable material removed from the bottom of the trench or excavation shall be replaced with select granular material placed in layers not exceeding 150 mm (6 inches) loose thickness.

1) Undisturbed: Bell holes shall be no larger than necessary for jointing. Backfill up to a point 300 mm (12 inches) above top of pipe shall be clean earth placed and tamped by hand.

2) Granular Fill: Depth of fill shall be a minimum of 75 mm (3 inches) plus one-sixth of pipe diameter below the pipe of 300 mm (12 inches) above top of pipe. Place and tamp fill material by hand.

c. Place and compact as specified the remainder of backfill using acceptable excavated materials. Do not use unsuitable materials.

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d. Use granular fill for bedding where rock or rocky materials are excavated.

e. Provide buried utility lines with utility identification tape.

Bury tape 300 mm (12 inches) below finished grade; under pavements and slabs, bury tape 150 mm (6 inches) below top of subgrade.

f. Bury detection wire directly above non-metallic piping at a distance not to exceed 300 mm (12 inches) above the top of pipe.

The wire shall extend continuously and unbroken, from manhole to manhole. The ends of the wire shall terminate inside the manholes at each end of the pipe, with a minimum of 0.9 m (3 feet) of wire, coiled, remaining accessible in each manhole. The wire shall remain insulated over its entire length. The wire shall enter manholes between the top of the corbel and the frame, and extend up through the chimney seal between the frame and the chimney seal. For force mains, the wire shall terminate in the valve pit at the pump station end of the pipe.

g. Bedding shall be of the type and thickness shown. Initial backfill material shall be placed and compacted with approved tampers to a height of at least one foot above the utility pipe or conduit. The backfill shall be brought up evenly on both sides of the pipe for the full length of the pipe. Care shall be taken to ensure thorough compaction of the fill under the haunches of the pipe. Except as specified otherwise in the individual piping section, provide bedding for buried piping in accordance with AWWA C600, Type 4, except as specified herein.

Backfill to top of pipe shall be compacted to 95 percent of ASTM

D698 maximum density. Plastic piping shall have bedding to spring line of pipe. Provide materials as discussed within

“Material Types & Compaction Levels” of the Geotechnical Report.

F. Site Earthwork: Excavation shall be accomplished as required by drawings and specifications. Remove subgrade materials that are determined by the COR as unsuitable, and replace with acceptable material. If there is a question as to whether material is unsuitable or not, the Contractor shall obtain samples of the material, under the direction of the COR, and the materials shall be examined by an independent testing laboratory for soil classification to determine whether it is unsuitable or not. When unsuitable material is

31 20 11 - 12 encountered and removed, the contract price and time will be adjusted in accordance with Articles, DIFFERING SITE CONDITIONS, CHANGES and

CHANGES-SUPPLEMENT of the GENERAL CONDITIONS as applicable. Adjustments to be based on meters (yardage) in cut section only.

G. Finished elevation of subgrade shall be as follows:

1. Pavement Areas - bottom of the pavement or base course as applicable.

2. Planting and Lawn Areas - 100 mm (4 inches) below the finished grade, unless otherwise specified or indicated on the drawings.

3.3 FILLING AND BACKFILLING:

A. General: Do not fill or backfill until all debris, unsatisfactory soil materials, obstructions, and deleterious materials have been removed from the excavation. Proof-roll exposed subgrades with a fully loaded dump truck. Use excavated materials or borrow for fill and backfill, as applicable. Do not use unsuitable excavated materials. Do not backfill until foundation walls have been completed above grade and adequately braced, waterproofing or damp proofing applied, and pipes coming in contact with backfill have been installed, and inspected and approved by COR.

B. Proof-rolling Existing Subgrade: - Proof rolling shall be done on an exposed subgrade free of surface water (wet conditions resulting from rainfall) which would promote degradation of an otherwise acceptable subgrade. After stripping, proof roll the existing subgrade of the parking areas and roadways with as discussed in the Subgrade

Preparation Option 1 – Normal Subgrade Preparation of the Geotechnical

Report. Notify the COR a minimum of 3 days prior to proof rolling.

Proof rolling shall be performed in the presence of the COR. Rutting or pumping of material shall be undercut as directed by the COR and replaced with select material.

C. Placing: Place material in horizontal layers not exceeding 200 mm (8 inches) in loose depth and then compacting. Do not place material on surfaces that are muddy, frozen, or contain frost.

D. Compaction: Use approved equipment (hand or mechanical) well suited to the type of material being compacted. Do not operate mechanized vibratory compaction equipment within 3000 mm (10 feet) of new or existing building walls without the prior approval of the COR. Moisten or aerate material as necessary to provide the moisture content that will readily facilitate obtaining the specified compaction with the

31 20 11 - 13 equipment used. Compact each layer to not less than that prescribed in the Geotechnical Report. Backfill adjacent to any and all types of structures shall be placed and compacted as discussed in Table 10.

Recommended Compaction Level within the Geotechnical Report. .

E. Borrow Material: Borrow material shall be selected to meet the requirements and conditions of the particular fill or embankment for which it is to be used. Borrow material shall be selected by the

Contractor. Unless otherwise provided in the contract, the Contractor shall obtain from the owners the right to procure material, pay royalties and other charges involved, and bear the expense of developing the sources, including rights-of-way for hauling. Unless specifically provided, no borrow shall be obtained within the limits of the project site without prior written approval. Necessary clearing, grubbing, and satisfactory drainage of borrow pits and the disposal of debris thereon shall be considered related operations to the borrow excavation.

3.4 GRADING:

A. General: Uniformly grade the areas within the limits of this section, including adjacent transition areas. Smooth the finished surface within specified tolerance. Provide uniform levels or slopes between points where elevations are indicated, or between such points and existing finished grades. Provide a smooth transition between abrupt changes in slope.

B. Cut rough or sloping rock to level beds for foundations. In unfinished areas fill low spots and level off with coarse sand or fine gravel.

C. Slope backfill outside the building away from the building walls for a minimum distance of 3048 mm (10 feet) at a minimum five percent (5%) slope.

D. The finished grade shall be 150 mm (6 inches) below bottom line of windows or other building wall openings unless greater depth is shown.

E. Place 12 inches of crushed stone followed by placing and compacting granular structural fill up to the bottom-of-the floor elevation. The final 6-inches of granular structural fill beneath the floor slab shall consist of select granular fill, unless otherwise indicated.

F. Finish subgrade in a condition acceptable to the COR at least one day in advance of the paving operations. Maintain finished subgrade in a smooth and compacted condition until the succeeding operation has been accomplished. Scarify, compact, and grade the subgrade prior to further

31 20 11 - 14 construction when approved compacted subgrade is disturbed by contractor's subsequent operations or adverse weather.

G. Grading for Paved Areas: Provide final grades for both subgrade and base course to +/- 6 mm (0.25 inches) of indicated grades.

3.5 LAWN AREAS:

A. General: Harrow and till to a depth of 100 mm (4 inches), new or existing lawn areas to remain, which are disturbed during construction.

Establish existing or design grades by dragging or similar operations.

Do not carry out lawn areas earthwork out when the soil is wet so that the tilth of the soil will be destroyed. Plant bed must be approved by

COR before seeding or sodding operation begins.

B. Finished Grading: Begin finish grading after rough grading has had sufficient time for settlement. Scarify subgrade surface in lawn areas to a depth of 100 mm (4 inches). Apply topsoil so that after normal compaction, dragging and raking operations (to bring surface to indicated finish grades) there will be a minimum of 100 mm (4 inches) of topsoil over all lawn areas; make smooth, even surface and true grades, which will not allow water to stand at any point. Shape top and bottom of banks to form reverse curves in section; make junctions with undisturbed areas to conform to existing topography. Solid lines within grading limits indicate finished contours. Existing contours, indicated by broken lines are believed approximately correct but are not guaranteed.

C. Fertilizing: Incorporate fertilizer into the soil to a depth of 100 mm

(4 inches) at a rate of 12 kg/100 m2 (25 pounds per 1000 square feet).

D. Sodding: Topsoil shall be firmed by rolling and during periods of high temperature the topsoil shall be watered lightly immediately prior to laying sod. Sod strips shall be tightly butted at the ends and staggered in a running bond fashion. Placement on slopes shall be from the bottom to top of slope with sod strips running across slope. Secure sodded slopes by pegging or other approved methods. Roll sodded area with a roller not to exceed 225 kg/m (150 pounds per foot) of the roller width to improve contact of sod with the soil.

E. Watering: The COR is responsible for having adequate water available at the site. As sodding is completed in any one section, the entire sodded area shall be thoroughly irrigated by the contractor, to a sufficient depth, that the underside of the new sod pad and soil, immediately

31 20 11 - 15 below sod, is thoroughly wet. COR will be responsible for sod after installation and acceptance.

3.6 DISPOSAL OF UNSUITABLE AND EXCESS EXCAVATED MATERIAL:

A. Disposal: Remove surplus satisfactory soil and waste material, including unsatisfactory soil, trash, and debris, and legally dispose of it off Medical Center property.

B. Place excess excavated materials suitable for fill and/or backfill on site where directed.

C. Remove from site and dispose of any excess excavated materials after all fill and backfill operations have been completed.

D. Segregate all excavated contaminated soil designated by the COR from all other excavated soils, and stockpile on site on two 0.15 mm (6 mil) polyethylene sheets with a polyethylene cover. A designated area shall be selected for this purpose. Dispose of excavated contaminated material in accordance with State and Local requirements.

3.7 CLEAN-UP:

Upon completion of earthwork operations, clean areas within contract limits, remove tools, and equipment. Provide site clear, clean, free of debris, and suitable for subsequent construction operations. Remove debris, rubbish, and excess material from the Medical Center.

- - - E N D - - -

GEOTEK ENGINEERING

& TESTING SERVICES, INC.

909 East 50th Street North Sioux Falls, South Dakota 57104 Phone 605-335-5512 Fax 605-335-0773

June 9, 2023

Paradigm Engineering and Consulting, PLLC 4350 Plainfield, NE Suite B Grand Rapids, Michigan 49525

Attn: Nicolas Sanchez, AIA

Subj: Geotechnical Exploration Proposed Boiler Plant VA Hospital W. 24th Street & S. Garfield Avenue Sioux Falls, South Dakota GeoTek #23-0352

This correspondence presents our written report of the geotechnical exploration program for the referenced project. Our work was performed in accordance with your authorization. We are transmitting an electronic copy of our report for your use.

We thank you for the opportunity of providing our services on this project and look forward to continued participation during the design and construction phases. If you have any questions regarding this report, please contact our office at (605) 335-5512.

Respectfully Submitted, GeoTek Engineering & Testing Services, Inc.

Nick Bierle

Nick Bierle, PE Project Engineer

Proposed Boiler Plant – VA Hospital Page 2 of 31 Sioux Falls, South Dakota GeoTek #23-0352

GeoTek Engineering & Testing Services, Inc.

TABLE OF CONTENTS

INTRODUCTION

PROJECT INFORMATION

SCOPE OF SERVICES

SITE & SUBSURFACE CONDITIONS

SITE LOCATION & DESCRIPTION

GROUND SURFACE ELEVATIONS & TEST BORING LOCATIONS

SUBSURFACE CONDITIONS

SOIL TYPES

Existing Fill Materials Loess Soils Glacial Till Soils

WATER LEVELS

ENGINEERING REVIEW & RECOMMENDATIONS

PROJECT DESIGN DATA

BOILER PLANT

Discussion Site Preparation – Footing Areas Site Preparation – Floor Slab Areas Alternative Support Option 1 – Rammed Aggregate Piers/Aggregate Piers Alternative Support Option 2 – Helical Piers Building Excavation & Soil Disturbance Dewatering Retaining/Below-Grade Walls Drain Tile Recommendations Seismic Site Classification

UNDERGROUND STORAGE TANKS

PAVEMENT AREAS

Discussion Initial Subgrade Preparation Subgrade Preparation Option 1 – Normal Subgrade Preparation Unstable Subgrade with Subgrade Preparation Option 1 Subgrade Preparation Option 2 – Subgrade Reinforcement Subgrade Preparation Option 3 – Cement Stabilization Pavement Section Thicknesses Earthwork Activities

FROST PROTECTION

Footings Surface Improvements

CORROSIVE POTENTIAL

MATERIAL TYPES & COMPACTION LEVELS

DRAINAGE

Proposed Boiler Plant – VA Hospital Page 3 of 31

CONSTRUCTION CONSIDERATIONS

GROUNDWATER & SURFACE WATER

DISTURBANCE OF SOILS

COLD WEATHER PRECAUTIONS

EXCAVATION SIDESLOPES

OBSERVATIONS & TESTING

EXCAVATION

TESTING

SUBSURFACE EXPLORATION PROCEDURES

TEST BORINGS

SOIL CLASSIFICATION

WATER LEVEL MEASUREMENTS

LABORATORY TESTS

LIMITATIONS

STANDARD OF CARE

APPENDIX A FIGURE 1 – SITE LOCATION MAP

FIGURE 2 – TEST BORING LOCATION MAP

FIGURE 3 – DIPRA 10-POINT SYSTEM

BORING LOGS

SOILS CLASSIFICATION

SYMBOLS & DESCRIPTIVE TERMINOLOGY

Proposed Boiler Plant – VA Hospital Page 4 of 31

GEOTECHNICAL EXPLORATION

PROPOSED BOILER PLANT

VA HOSPITAL

W. 24TH STREET & S. GARFIELD AVENUE

SIOUX FALLS, SOUTH DAKOTA

GEOTEK #23-0352

INTRODUCTION

Project Information

This report presents the results of the recent geotechnical exploration program for the proposed boiler plant located at the existing VA Hospital in Sioux Falls, South Dakota.

Scope of Services

Our work was performed in accordance with the authorization of Nicolas Sanchez with Paradigm

Engineering and Consulting, PLLC. The scope of work as presented in this report is limited to the following:

1. To perform 4 standard penetration test (SPT) borings to gather data on the subsurface conditions at the project site.

2. To perform laboratory tests that include moisture content, dry density, Atterberg limits (liquid and plastic limits), unconfined compressive strength, pH, sulfate content, chloride content, resistivity, redox potential and sulfide content.

3. To prepare an engineering report that includes the results of the field and laboratory tests as well as our earthwork and foundation recommendations for design and construction.

The scope of our work was intended for geotechnical purposes only. This scope of work did not include determining the presence or extent of environmental contamination at the site or to characterize the site relative to wetlands status.

Proposed Boiler Plant – VA Hospital Page 5 of 31

SITE & SUBSURFACE CONDITIONS

Site Location & Description

The site is located at the existing VA Hospital in Sioux Falls, South Dakota. The area designated for the proposed boiler plant is located southeast of the intersection of W. 24th Street and S.

Garfield Avenue. A site location map (Figure 1) is attached showing the location of the site. The topography of the site slopes downward from east to west.

Ground Surface Elevations & Test Boring Locations

The ground surface elevations at the test boring locations were determined by using the top of manhole cover that is located northwest of test boring 1 as a benchmark datum. An elevation of

1,489.4 was used for the benchmark. Based on the benchmark, the elevations at the test borings were 1,490.2 feet at test boring 1, 1,491.3 feet at test boring 2, 1,492.5 feet at test boring 3 and

1,493.9 feet at test boring 4. A test boring location map (Figure 2) is attached showing the relative location of the test borings.

Subsurface Conditions

We performed 4 test borings at the site on April 5 and April 14, 2023. The subsurface conditions encountered at the test boring locations are illustrated by means of the boring logs included in

Appendix A.

The subsurface profile at the test borings consisted of the following soil types: existing fill materials, topsoil (buried) materials, loess soils and glacial till soils. In addition, concrete (7” thick) and gravel base materials (8” thick) was encountered at the surface of test boring 1. The existing fill materials were encountered at each test boring and extended to depths varying from

2 feet to 9 ½ feet. The buried topsoil materials were only encountered beneath the existing fill materials at test boring 1 and had at thickness of 1 ½ feet. The loess soils were encountered below the existing fill materials at all of the test borings and extended to depths (deeper test boings) varying from 19 ½ feet to 24 ½ feet. The loess soils extended to the termination depth of test boring 4 (shallow test boring). The glacial till soils were encountered beneath the loess soils

Proposed Boiler Plant – VA Hospital Page 6 of 31 at test borings 1, 2 and 3 (deeper test borings) and extended to the termination depth of the test borings.

The consistency or relative density of the soils is indicated by the standard penetration resistance

(“N”) values as shown on the boring logs. A description of the soil consistency or relative density based on the “N” values can be found on the attached Soil Boring Symbols and

Descriptive Terminology data sheet.

We wish to point out that the subsurface conditions at other times and locations at the site may differ from those found at our test boring locations. If different conditions are encountered during construction, then it is important that you contact us so that our recommendations can be reviewed.

Soil Types

Existing Fill Materials

The existing fill materials consisted of lean clay (CL), sandy lean clay (CL) and lean clay with sand (CL). “N” values within the existing fill materials ranged from 3 to 13. The moisture condition of the existing fill materials was moist and wet.

Topsoil Materials

The topsoil materials consisted of lean clay (CL). An “N” value of 5 (consistency of firm) was measured within the topsoil materials at test boring 1. The moisture condition of the topsoil materials was moist.

Loess Soils

Loess soils are soils that have been deposited by wind. The loess soils consisted of lean clay

(CL). “N” values within the loess soils ranged from 3 to 10 (consistency of soft, firm and stiff).

The moisture condition of the loess soils was moist and wet.

Proposed Boiler Plant – VA Hospital Page 7 of 31

Glacial Till Soils

Glacial till soils consist of silt and clay sized particles with sand and gravel intermixed that have been deposited and consolidated by a glacier. The glacial till soils consisted of lean clay with sand (CL). “N” values within the glacial till soils ranged from 7 to 16 (consistency of firm, stiff and very stiff). The moisture condition of the glacial till soils was moist.

Water Levels

Measurements to record the groundwater levels were made at the test boring locations. The time and level of the groundwater readings are recorded on the boring logs. Groundwater was measured at a depth of 8 feet (elevation 1,482.2 feet) at test boring 1 and 9 feet (elevation

1,482.3 feet) at test boring 2. Groundwater did not enter the remaining boreholes at the time of our measurements. However, we expect that similar or shallower groundwater would be encountered as test borings 1 and 2 if the boreholes were to remain open for an extended period of time.

The water levels may or may not be an accurate indication of the depth or lack of subsurface groundwater. The limited length of observation restricts the accuracy of the measurements. Long term groundwater monitoring was not included in our scope of work.

ENGINEERING REVIEW & RECOMMENDATIONS

Project Design Data

We understand that the project will consist of constructing a boiler plant at the existing VA

Hospital in Sioux Falls, South Dakota. The boiler plant will be a slab-on-grade structure with approximate dimensions of 60 feet by 100 feet by 28 feet (tall). In addition, a mezzanine will be located within the boiler plant. We understand that the finished floor of the boiler plant will be

1,491.0 feet. Based on the existing surface grades within the footprint of the boiler plant and the finished floor elevation (FFE), cutting of up to 2 feet will be needed in order to achieve the FFE.

We anticipate that foundation support for the boiler plant will be provided by perimeter footings resting below frost depth and interior footings resting at or slightly below the floor slab. We

Proposed Boiler Plant – VA Hospital Page 8 of 31 understand that the maximum wall loads will be up to 5 klf and the maximum column loads will be up to 170 kips. Regarding floor slab loads, we understand that the floor loads will range from

200 pounds per square foot (psf) to 600 psf. The 600 psf floor slab load will be in the area where the boilers are located.

The project will also consist of constructing pavement areas and installation of three (3) underground storage tanks. Grade changes in the pavement areas will likely include minimal cutting and filling of up to 3 feet in order to achieve the design elevations. The vehicle traffic will likely consist of automobiles and trucks (snow removal and garbage). In regards to the underground storage tanks, we assume that the bottom of the storage tanks will rest approximately 15 feet below finished grade. In addition, each storage tank will have a capacity of approximately 80,000 gallons.

The information/assumptions detailed in the project design data section are important factors in our review and recommendations. If there are any corrections or additions to the information detailed in this section, then it is important that you contact us so that we can review our recommendations with regards to the revised plans.

Boiler Plant

Discussion

The test borings performed for the boiler plant indicate that the existing fill materials extended to depths of 7 ½ feet and 12 feet. In our opinion, the field and laboratory data indicate that the majority of the existing fill materials were not placed and compacted in a controlled manner.

Therefore, it is our opinion that the existing fill materials are not suitable for support of the floor slab or footings of the boiler plant. In addition, it is our opinion that the buried topsoil materials are not suitable for support of the floor slab or footings of the boiler plant. The loess soils extended to depths varying from 19 ½ feet to 24 ½ feet within the footprint of the boiler plant.

Based on the consistency (generally soft and firm) and unconfined compressive strength values

(0.2 tons per square foot (tsf) and 0.4 tsf), it is our opinion that the loess soils have low strength levels. In addition, it is our opinion that the loess soils are moderately compressible. Therefore, it is our opinion that in order to provide adequate support for the floor slab and footings of the

Proposed Boiler Plant – VA Hospital Page 9 of 31 boiler plant, we recommend that an overexcavation be performed below the floor slab and footings or an intermediate foundation system be used below the floor slab and footings. The intermediate foundation system would consist of rammed aggregate piers/aggregate piers or helical piers.

Site Preparation – Footing Areas

The site preparation in footing (exterior and interior) areas should consist of removing the pavement, gravel base, vegetation, buried topsoil materials and existing fill materials in order to expose the loess soils. Following the removals, we recommend that additional removals be performed beneath the footings. The depth of the overexcavation will depend on the type of footing. For continuous footings, the overexcavation should extend to a minimum depth of one

(1) footing width beneath the bottom-of-footing elevation (example: a 2 foot wide continuous footing would require a 2 foot overexcavation). For individual column pad footings, the overexcavation should extend to a minimum depth of one-half (½) column pad width below the bottom-of-footing elevation (example: a 8 foot by 8 foot column pad would require a 4 foot overexcavation).

Following overexcavation, we recommend that observations and hand auger borings be performed at the bottom of the excavations. Unstable areas may require additional removals.

Once the bottom of the excavations are approved, the overexcavated areas should be backfilled with 12 inches of crushed rock followed by placing and compating granular structural fill up to the bottom-of-footing elevation.

It is our opinion that a friction factor of 0.45 can be used between the granular structural fill or crushed rock and the bottom of the concrete. The friction value is considered an ultimate value.

We recommend applying a theoretical safety factor of at least 2.0.

The bottom of the excavations should be laterally oversized 1 foot beyond the edges of the footings for each vertical foot of crushed rock or granular structural fill needed below the footings (1 horizontal : 1 vertical).

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If our recommendations are followed during site preparations, then it is our opinion that the footings of the boiler plant could be sized for a net allowable soil bearing pressure of up to 2,000 psf. With the net allowable soil bearing pressure and our site preparation recommendations, we recommend limiting the wall loads to 5 klf and the column loads to 170 kips. If a higher net allowable soil bearing pressure is desired or the load limits are exceeded, then we recommend that we be contacted to provide additional recommendations.

With the load limits, net allowable soil bearing pressure and our site preparation recommendations, total settlement of these footings should be less than 1 inch and differential settlement should be less than ½ inch over 50 feet. Unknown soil conditions at the site that are different from those depicted at the test locations could increase the amount of expected settlement.

Site Preparation – Floor Slab Areas

The site preparation in floor slab areas should consist of removing the pavement, gravel base, vegetation, buried topsoil materials and existing fill materials in order to expose the loess soils.

Following removals, we recommend that observations and hand auger borings be performed at the bottom of the excavations. Unstable areas may require additional removals. Please refer to

Table 1 for a summary of the anticipated minimum excavation depths to remove the unsuitable soils encountered at the test borings performed for the boiler plant. The depth of the excavation may vary within the footprint of the boiler plant. We would like to point out that our recommendations are based on a FFE of 1,491.0 feet. If the FFE is changed, then we recommend that we be contacted to review our recommendations.

Table 1. Estimated Excavation Depths – Floor Slab Test Boring

Number Ground Surface

Elevation, ft Anticipated Excavation

Depth, ft Approximate Excavation

Elevation, ft 1 1,490.2 12 1,478.2 2 1,491.3 7 ½ 1,483.8

Once the bottom of the excavations are approved, the overexcavated areas should be backfilled with 12 inches of crushed rock followed by placing and compacting granular structural fill up to

Proposed Boiler Plant – VA Hospital Page 11 of 31 the bottom-of-floor elevation. The final 6 inches of granular structural fill beneath the floor slab should consist of select granular fill.

If our recommendations are followed during site preparations, then it is our opinion that the floor slabs can be designed using a soil modulus of subgrade reaction (k value) of 125 psi/inch.

Alternative Support Option 1 – Rammed Aggregate Piers/Aggregate Piers

This alternative support option 1 consists of installing rammed aggregate piers or aggregate piers beneath the entire boiler plant (floor slab and footings). Prior to the installation of the rammed aggregate piers or aggregate piers, the design elevations within and around the boiler plant should be achieved by cutting or placing and compacting subgrade fill.

We recommend that the rammed aggregate piers or aggregate piers be designed by a licensed professional engineer specializing in the design of rammed aggregate piers or aggregate piers.

With the rammed aggregate piers or aggregate piers, there are several support and sequencing options that could be considered. Discussions with the rammed aggregate pier or aggregate pier designer should be made to determine the best course of action. The designer will typically provide a net allowable soil bearing pressure (typically in the range of 4,000 pounds per square foot to 5,000 psf), estimated settlements and a coefficient of friction. Additionally, we recommend that discussions with the designer be done regarding any potential time delay. The rammed aggregate piers or aggregate piers should be installed by an experienced licensed rammed aggregate pier or aggregate pier contractor.