ST. CHARLES ELEMENTARY ADDITION & …...joint. Therefore, we recommend implementing a detailed maintenance program to seal and/or fill any cracks and joints. The maintenance program

NCF-0002 (8/17)

St Charles Public Schools600 East 6th Street

St. Charles, MN 55972

ST. CHARLES ELEMENTARY ADDITION & RENOVATIONSVOLUME I – Sections 00 - 12

Request for Bids

Bid Details:St. Charles Elementary

925 Church AvenueSt. Charles, MN 55972

Document Date:April 01, 2020

Drawings Date:March 27, 2020

Bid Request Prepared By:

6885 Sycamore Ln. NorthSuite 200

Maple Grove, MN 55369763.201.8400

PROJECT TITLE PAGE SECTION – 00 0001

St. Charles Public SchoolsSt. Charles ElementaryAddition and Renovations Page 1 of 2

SECTION 00 0001

PROJECT TITLE PAGE

1.1 Owner:St. Charles Public School District600 East 6th StreetSt Charles, MN 55972Contact: Mr. Jeff Apse - Superintendent of Schools

A.1.2 Owners Program Manager:

Nexus Solutions, LLC6885 Sycamore Lane NorthSuite 200Maple Grove, MN 55369

1.3 Project Manager:Nexus Solutions, LLC6885 Sycamore Lane NorthSuite 200Maple Grove, MN 55369Contact: Adam FrankenbergPhone: 952-913-5785Email: [email protected]

1.4 Architect:HSR Associates, Inc.100 Milwaukee StreetLa Crosse, WI 54603Contact: Lee QuPhone: (608) 784-1830Email: [email protected]

1.5 Structural Engineer:Sandman SE10900 Noble Avenue NorthChamplin, MN 55316Contact: Greg DuerrPhone: (763) 560-5300Email: [email protected]

1.6 Foodservice Consultant:LJG Design, LLC6451 Pleasant Park DriveChanhassen, MN 55317Contact: Len GroschenPhone: (952) 405-8121Email: [email protected]

mailto:[email protected]:[email protected]:[email protected]:[email protected]

PROJECT TITLE PAGE SECTION – 00 0001


1.7 Mechanical Engineer:Nexus Solutions, LLC6885 Sycamore Lane NorthSuite 200Maple Grove, MN 55369Contact: Russ SchumacherPhone: (763) 201-8400Email: [email protected]

1.8 Electrical Engineer:Galileo Consulting Group2920 East Avenue SouthLa Crosse, WI 54601Contact: Pat PopowichPhone: (608) 787-9106Email: [email protected]

1.9 Civil Engineer:Larson Engineering, Inc.3524 Labore RoadWhite Bear Lake, MN 55110Contact: Matt WoodruffPhone: 651-481-9120Email: [email protected]

END OF SECTION

mailto:[email protected]:[email protected]:[email protected]

TABLE OF CONTENTS 00 0005


TABLE OF CONTENTSVol 1. – Sections 00 – 12Vol. 2 – Sections 20 – 33

SPECIFICATIONS No. of Pages

DIVISION 00 – BIDDING & CONTRACT REQUIREMENTS00 0001 Project Title Page........................................................................................... 200 0005 Table of Contents........................................................................................... 400 0010 Certifications.................................................................................................. 400 1100 Call for Bids................................................................................................... 100 2000 Instructions to Bidders (AIA Document A701 – 2018)................................. 700 3119 Existing Conditions........................................................................................ 4500 3126 Existing Hazardous Material Information ..................................................... 1300 4100 Bid Form ........................................................................................................ 500 4200 Responsible Contractor Affidavit .................................................................. 100 4325 Substitutions Request..................................................................................... 200 4340 Bid Security (AIA Document A310 – 2010) ................................................. 300 5200 Form of Agreement (AIA Document A132 – 2009)...................................... 1200 5202 Responsible Contractor Verifications of Compliance ................................... 100 6100 Performance and Payment Bonds (AIA Document A312 – 2010) ................ 900 6200 Certificate of Insurance.................................................................................. 100 7010 General Conditions (AIA Document A232 – 2009) ...................................... 5900 9100 Addenda ......................................................................................................... 1

DIVISION 01 - GENERAL REQUIREMENTS01 0200 Milestone Schedule........................................................................................ 101 1000 Summary of Work......................................................................................... 3201 2300 Alternates ....................................................................................................... 101 2900 Payment Procedures....................................................................................... 401 3100 Project Management and Coordination ......................................................... 501 3126 Electronic Communication Protocol.............................................................. 201 3300 Submittal Procedures ..................................................................................... 401 4000 Quality Requirements .................................................................................... 401 5000 Temporary Facilities ...................................................................................... 401 5200 Safety ............................................................................................................. 301 7123 Field Engineering........................................................................................... 101 7329 Cutting and Patching...................................................................................... 301 7413 Progress Cleaning .......................................................................................... 201 7700 Closeout Procedures ...................................................................................... 401 7823 Operations and Maintenance Data................................................................. 101 7900 Demonstration and Training .......................................................................... 2

DIVISION 02 – EXISTING CONDITIONS02 1000 Selective Demolition - Civil .......................................................................... 202 4100 Demolition - Architectural............................................................................. 2

DIVISION 03 – CONCRETE03 1000 Concrete Forming and Accessories ............................................................... 303 2000 Concrete Reinforcing..................................................................................... 303 3000 Cast in Place Concrete ................................................................................... 10



DIVISION 04 – MASONRY04 0511 Mortar and Masonry Grout ............................................................................ 404 2000 Unit Masonry ................................................................................................. 704 7200 Cast Stone Masonry ....................................................................................... 5

DIVISION 05 – METALS05 1200 Structural Steel Framing ................................................................................ 305 2100 Steel Joist Framing......................................................................................... 205 3100 Steel Decking ................................................................................................. 305 5000 Metal Fabrications ......................................................................................... 205 5133 Metal Ladders ................................................................................................ 3

DIVISION 06 – WOOD, PLASTICS AND COMPOSITES06 1000 Rough Carpentry............................................................................................ 206 2000 Finish Carpentry ............................................................................................ 106 4100 Architectural Wood Casework....................................................................... 406 6100 Cast Polymer Fabrications ............................................................................. 2

DIVISION 07 – THERMAL AND MOISTURE PROTECTION07 0553 Fire and Smoke Assembly Identification....................................................... 207 2100 Thermal Insulation ......................................................................................... 307 2119 Foamed-In-Place Insulation ........................................................................... 607 5300 Elastomeric Membrane Roofing .................................................................... 507 6200 Sheet Metal Flashing and Trim...................................................................... 207 8123 Intumescent Fire Protection ........................................................................... 207 8400 Firestopping ................................................................................................... 507 9100 Preformed Joint Seals .................................................................................... 207 9200 Joint Sealants ................................................................................................. 607 9513 Expansion Joint Cover Assemblies................................................................ 2

DIVISION 08 – OPENINGS08 1113 Hollow Metal Doors and Frames................................................................... 408 1416 Flush Wood Doors ......................................................................................... 308 1613 Fiberglass Doors ............................................................................................ 608 3313 Coiling Counter Doors................................................................................... 208 4313 Aluminum Framed Storefronts ...................................................................... 508 6200 Unit Skylights ................................................................................................ 308 7100 Door Hardware............................................................................................... 1008 8000 Glazing........................................................................................................... 508 8723 Safety and Security Films .............................................................................. 2

DIVISION 09 – FINISHES09 0561 Common Work Results for Flooring Preparation.......................................... 409 2116 Gypsum Board ............................................................................................... 609 3000 Tile ................................................................................................................. 209 5100 Acoustical Ceiling.......................................................................................... 309 6500 Resilient Flooring .......................................................................................... 309 6623 Resinous Matrix Terrazzo Flooring............................................................... 309 6813 Tile Carpeting ................................................................................................ 2



09 8430 Sound Absorbing Wall and Ceiling Units ..................................................... 209 9113 Exterior Painting ............................................................................................ 409 9123 Interior Painting ............................................................................................. 6

DIVISION 10 – SPECIALTIES10 2800 Toilet, Bath and Laundry Accessories........................................................... 310 4400 Fire Protection Specialties ............................................................................. 210 5113 Metal Lockers ................................................................................................ 2

DIVISION 11 – EQUIPMENT11 4000 Foodservice Equipment ................................................................................. 3011 6623 Gymnasium Equipment.................................................................................. 2

DIVISION 12 – FURNISHINGS12 2400 Window Shades ............................................................................................. 212 6823 Folding Cafeteria Tables................................................................................ 3

DIVISION 20 - MECHANICAL COMMON WORK RESULTS20 1000 Mechanical General Provisions ..................................................................... 920 1010 Basic Materials and Methods......................................................................... 1220 1020 Motors ............................................................................................................ 720 1030 Pipe Expansion Fittings and Loops ............................................................... 320 1040 Meters and Gauges......................................................................................... 520 1050 Valves ............................................................................................................ 620 1060 Hangers and Supports .................................................................................... 1320 1070 Mechanical Vibration Control ....................................................................... 720 1080 Mechanical Identification .............................................................................. 620 1090 Penetration Firestopping................................................................................ 820 1100 Piping Insulation ............................................................................................ 1020 1200 Duct Insulation............................................................................................... 8

DIVISION 21 - FIRE SUPPRESSION21 1050 Fire Protection - Remodel.............................................................................. 5

DIVISION 22 – PLUMBING22 1116 Domestic Water Piping Systems.................................................................... 922 1125 Domestic Water Pumps.................................................................................. 422 1313 Sanitary and Storm Waste Piping Systems.................................................... 1022 4000 Plumbing fixtures........................................................................................... 9

DIVISION 23 – HEATING VENTILATING AND AIR CONDITIONING23 1123 Natural Gas Piping......................................................................................... 823 2113 Hydronic Piping Systems............................................................................... 1223 2123 Hydronic and Domestic Water Pumps........................................................... 523 2500 HVAC Water Treatment ................................................................................ 423 3113 Metal Ducts.................................................................................................... 1023 3300 Duct Accessories............................................................................................ 1123 3417 Exhaust Fans .................................................................................................. 523 3600 Air Terminal Units......................................................................................... 423 3713 Diffusers, Registers and Grilles ..................................................................... 323 5200 Boilers and Accessories ................................................................................. 8



23 7410 Packaged Rooftop Units ................................................................................ 1023 8233 Finned Tube Radiation................................................................................... 323 8238 Suspended Unit Heaters................................................................................. 323 8239 Cabinet Unit Heaters...................................................................................... 4

DIVISION 24 – CONTROLS, TESTING AND BALANCING, COMMISSIONING24 0100 Instrumentation and Control for HVAC ........................................................ 2624 0200 Sequence of Operations for HVAC controls ................................................. 2324 0500 Testing Adjusting and Balancing................................................................... 1924 0700 HVAC System Commissioning ..................................................................... 4

DIVISION 26 – ELECTRICAL26 0500 Common Work Results for Electrical............................................................ 926 0502 Electrical Demolition for Remodeling........................................................... 205 0504 Cleaning, Inspection and Testing Electrical Equipment................................ 326 0514 Variable Frequency Drive.............................................................................. 426 0519 Low Voltage Electrical Power Conductors and Cables................................. 626 0523 Control-Voltage Electrical Power Cables...................................................... 426 0526 Grounding and Bonding for Electrical Systems ............................................ 426 0529 Hangers and Supports for Electrical Systems................................................ 226 0533 Raceways and Boxes for Electrical Systems ................................................. 826 0536 Cable Trays .................................................................................................... 626 0553 Identification for Electrical Systems.............................................................. 426 2416 Panelboards .................................................................................................... 326 2702 Electrical Wiring Systems ............................................................................. 526 2726 Wiring Devices .............................................................................................. 626 2728 Disconnect Switches ...................................................................................... 226 2813 Fuses .............................................................................................................. 126 2816 Enclosed Switches and Circuit Breakers ....................................................... 226 2900 Low-Voltage Controllers ............................................................................... 426 5113 LED Lighting Fixtures................................................................................... 3

DIVISION 27 – COMMUNICATIONS27 5116 Public Address Systems................................................................................. 4

DIVISION 28 – ELECTRICAL SAFETY AND SECURITY28 3100 Fire Alarm Detection System......................................................................... 14

DIVISION 31 – EARTHWORK31 2000 Earth Work..................................................................................................... 1131 2323.43Geofoam......................................................................................................... 231 2500 Temporary Erosion Control ........................................................................... 331 3000 Geotextiles and Fabrics.................................................................................. 3

DIVISION 32 – EXTERIOR IMPROVEMENTS32 0500 Aggregates ..................................................................................................... 532 1000 Plant Mix Bituminous Pavement ................................................................... 832 2000 Concrete Pavement ........................................................................................ 832 2400 Pavement Striping.......................................................................................... 232 2600 Signs............................................................................................................... 3



32 5000 Fences and Gates ........................................................................................... 432 5800 Landscaping ................................................................................................... 4

DIVISION 33 – UTILITIES33 3000 Sanitary Sewer ............................................................................................... 333 4000 Storm Drainage System ................................................................................. 433 4200 Drain Tile....................................................................................................... 2

St. Charles Public Schools St. Charles Elementary Addition and Renovations Page 1 of 2

ARCHITECTURAL SPECIFICATION

ST. CHARLES PUBLIC SCHOOLS

ST. CHARLES ELEMENTARY ADDITION AND RENOVATIONS

I hereby certify that this specification was prepared by me or under my direct supervision and

that I am duly licensed Professional Engineer under the laws of the State of Minnesota. QIULI QU Registration # 56867


This Sheet Left Blank Intentionally


CIVIL SPECIFICATION



I hereby certify that this specification was prepared by me or under my direct supervision and that I am duly licensed Professional Engineer under the laws of the State of Minnesota.

Justin Nielsen Registration # 52687


MECHANICAL SPECIFICATION



I hereby certify that this specification was prepared by me or under my direct supervision and that I am duly licensed Professional Engineer under the laws of the State of Minnesota.

Russell D. Schumacher Registration # 26440

CALL FOR BID 00 1100


CALL FOR BIDS

INDEPENDENT SCHOOL DISTRICT NO. 858

St. Charles Public Schools

Independent School District #858, St. Charles Public Schools will receive sealed bids in duplicate for: St. Charles Public Schools – St. Charles Elementary Addition and Renovations – until 10:00 AM on Thursday April 23, 2020.

Bids will be received by the Superintendent of Schools – Jeff Apse at the District #858 District Offices, 600 E 6th St. Charles, MN 55972 then publicly opened and read aloud. There is no agent for the receipt of bids other than the Superintendent of Schools – Jeff Apse.

Bids shall be submitted on bid form provided by the Bid Documents. The completed bid form shall be submitted without alterations, additions or erasures. Envelopes containing bids must be sealed marked separately “St. Charles Public Schools – St. Charles Elementary Addition and Renovations” with the name and address of the bidder, and the date and hour of the opening. Bids shall be delivered to:

Mr. Jeff ApseSuperintendent of SchoolsIndependent School District #858 - District Office600 E 6th StSt Charles, MN 55972

Lump sum bids for the defined work scopes are solicited from contractors specializing in, highly experienced in this work.

Procurement of documents: Nexus Solutions6885 Sycamore LN. N., Ste. 200Maple Grove, MN 55369Amy SeiberlichPhone: [email protected]

Bidding documents will be available on or about April 3, 2020. Each bid of $10,000 or greater shall be accompanied by a certified or cashier’s check, or a bid bond in the amount of at least five (5%) percent of the amount of the bid made payable to ISD #858 as bid security that, if the bid is accepted, the contractor will execute the contract and file the required performance and payment bonds within the allotted time period after notice of award of contract.

Pre-Bid Walk through scheduled for Tuesday April 14th, 2020 at 10:00am. Located at the St. Charles Elementary School 925 Church Ave St Charles, MN 55972.

The Board of Education reserves the right to accept or reject any or all bids or parts of bids and waive any formalities or irregularities in the bidding. No bid may be withdrawn for a period of forty-five (45) days after bid opening without consent of the Board of Education.

ST. CHARLES PUBLIC SCHOOLSSt. Charles, Minnesota

Publication Dates via ISD #858 Official Paper: The St. Charles PressDates of Publication: April 9, 2020 and April 16, 2020

mailto:[email protected]

EXISTING CONDITIONS INFORMATION 00 3119


SECTION 00 3119 – EXISTING CONDTIONS INFORMATION

PART 1 - GENERAL

1.1 Scope

A. This section provides information resulting from subsurface investigations completed at the site as part of this project. This section may contain information applicable to ALL sitework, and other technical specification sections, as well, as required. All Contractors are expected to review this information as part of their duties to familiarize themselves with the site. Results of the site borings apply only to the locations at which data was collected, at the specific time it was collected. Geotechnical conditions may differ elsewhere on the site. Geotechnical investigations completed by Bidder shall comply with all applicable requirements of Division 01 through Division 34 of this project. This report is for information only.

B. Prior to making additional investigations of their own using test pits, borings, or other methods; Bidder shall first gain permission from Owner and Nexus Project Manager.

1.2 Related Requirements

A. Applicable provisions of Division 01 govern work under this section1. 00 0200 Instruction to Bidders

PART 2 - PRODUCTS

NOT USED

PART 3 – EXECUTION

NOT USED

ATTACHMENTS:

Geotechnical Evaluation Report – St. Charles School District Referendum Project – Elementary School

END OF SECTION 00 3119

Geotechnical Evaluation Report St. Charles School District Referendum Project – Elementary School 925 Church Avenue St. Charles, Minnesota Prepared for

St. Charles Public Schools ISD #858 Professional Certification: I hereby certify that this plan, specification, or report was prepared by me or under my direct supervision and that I am a duly licensed Professional Engineer under the laws of the State of Minnesota.

Ray A. Huber, PE Vice President, Principal Engineer License Number: 15329 March 11, 2020 Project B2001024 Braun Intertec Corporation

AA/EOE

Braun Intertec Corporation 4210 Highway 14 East Rochester, MN 55904

Phone: 507.281.2515 Fax: 507.281.5303 Web: braunintertec.com

March 11, 2020 Project B2001024 Mr. Jeff Apse St. Charles Public Schools ISD #858 600 East 6th Street St. Charles, MN 55972 Re: Geotechnical Evaluation St. Charles School District Referendum Projects – Elementary School 925 Church Avenue St. Charles, Minnesota Dear Mr. Apse: We are pleased to present this Geotechnical Evaluation Report for the St. Charles Elementary School Addition in St. Charles, Minnesota. Thank you for making Braun Intertec your geotechnical consultant for this project. If you have questions about this report, or if there are other services that we can provide in support of our work to date, please contact Connor Burke at 507.884.5474 or [email protected]. Sincerely, BRAUN INTERTEC CORPORATION Connor R. Burke, EIT Staff Engineer

Ray A. Huber, PE Vice President, Principal Engineer c: Shawn Anderson, Nexus Solutions Adam Frankenberg, Nexus Solutions Pete Johnson, Nexus Solutions Wayne Linderman, Sandman Structural Engineers Justin Nielsen, Larson Engineering, Inc

Table of Contents

Description Page A. Introduction ...................................................................................................................................... 1

A.1. Project Description .............................................................................................................. 1 A.2. Site Conditions and History ................................................................................................. 3 A.3. Purpose ................................................................................................................................ 3 A.4. Background Information and Reference Documents .......................................................... 4 A.5. Scope of Services ................................................................................................................. 4

B. Results .............................................................................................................................................. 6 B.1. Geologic Overview .............................................................................................................. 6 B.2. Boring Results ...................................................................................................................... 6 B.3. Bedrock ................................................................................................................................ 8 B.4. Groundwater ....................................................................................................................... 9 B.5. Laboratory Test Results ....................................................................................................... 9

C. Recommendations ......................................................................................................................... 10 C.1. Design and Construction Discussion ................................................................................. 10 C.2. Site Grading and Subgrade Preparation ............................................................................ 11

C.2.a. Building Subgrade Excavations ............................................................................. 11 C.2.b. Excavation Oversizing ........................................................................................... 12 C.2.c. Excavated Slopes .................................................................................................. 13 C.2.d. Excavation Dewatering ......................................................................................... 14 C.2.e. Pavement and Exterior Slab Subgrade Preparation ............................................. 14 C.2.f. Pavement Subgrade Proofroll .............................................................................. 14 C.2.g. Engineered Fill Materials and Compaction .......................................................... 15 C.2.h. Special Inspections of Soils ................................................................................... 16

C.3. Spread Footings ................................................................................................................. 17 C.4. Construction Adjacent to Existing Structures .................................................................... 17

C.4.a. Excavations ........................................................................................................... 17 C.4.b. Settlement ............................................................................................................ 18

C.5. Interior Slabs ..................................................................................................................... 18 C.5.a. Subgrade Modulus ............................................................................................... 18 C.5.b. Moisture Vapor Protection .................................................................................. 18

C.6. Frost Protection ................................................................................................................. 19 C.6.a. General ................................................................................................................. 19 C.6.b. Frost Heave Mitigation ......................................................................................... 19

C.7. Pavements and Exterior Slabs ........................................................................................... 21 C.7.a. Design Sections .................................................................................................... 21 C.7.b. Bituminous Pavement Materials .......................................................................... 21 C.7.c. Subgrade Drainage ............................................................................................... 21 C.7.d. Performance and Maintenance ........................................................................... 21

C.8. Utilities .............................................................................................................................. 22 C.8.a. Subgrade Stabilization .......................................................................................... 22 C.8.b. Corrosion Potential .............................................................................................. 22

St. Charles Public Schools ISD #858 Project B2001024 March 11, 2020 Page 2

C.9. Equipment Support ........................................................................................................... 23 D. Procedures...................................................................................................................................... 23

D.1. Penetration Test Borings ................................................................................................... 23 D.2. Exploration Logs ................................................................................................................ 23

D.2.a. Log of Boring Sheets ............................................................................................. 23 D.2.b. Geologic Origins ................................................................................................... 24

D.3. Material Classification and Testing ................................................................................... 24 D.3.a. Visual and Manual Classification .......................................................................... 24 D.3.b. Laboratory Testing ............................................................................................... 24

D.4. Groundwater Measurements ............................................................................................ 24 E. Qualifications .................................................................................................................................. 25

E.1. Variations in Subsurface Conditions .................................................................................. 25 E.1.a. Material Strata ..................................................................................................... 25 E.1.b. Groundwater Levels ............................................................................................. 25

E.2. Continuity of Professional Responsibility .......................................................................... 25 E.2.a. Plan Review .......................................................................................................... 25 E.2.b. Construction Observations and Testing ............................................................... 26

E.3. Use of Report..................................................................................................................... 26 E.4. Standard of Care ................................................................................................................ 26

Appendix Soil Boring Location Sketch Fence Diagram Log of Boring Sheets ES-1 through ES-9 Descriptive Terminology of Soil Descriptive Terminology of Rock

A. Introduction

A.1. Project Description

This Geotechnical Evaluation Report addresses the proposed design and construction of the Elementary

School, located in St. Charles, Minnesota. The project will include the construction a building addition,

new pavements, and associated site utilities. Tables 1 and 2 provide project details.

Table 1. Building Description

Aspect Description

Below grade levels None (Provided)

Above grade levels Two – West portion of addition One – East portion of addition

(Provided)

Lowest level floor elevation 1135.04 MSL (Provided)

Column loads (kips) 22 kips (Provided)

Wall loads (kips per linear foot) 6 (Provided)

Nature of construction

Cast-in-place spread footings, and foundation walls, and grade beams supported on helical piers where

tying into existing building. There will be CMU walls, and steel framing.

Cuts or fills for buildings Less than 1-foot (Assumed)

Tolerable building settlement Less than 1 inch of total settlement.

Less than 1/2 inch of differential settlement. (Assumed)

Table 2. Site Aspects and Grading Description

Aspect Description

Pavement type(s) Bituminous

Assumed pavement loads Light-duty: 50,000 ESALs*

Grade changes Less than 1-foot cut and 1-foot fill feet (Provided)

*Equivalent 18,000-lb single axle loads based on 20-year design.


The figure below shows an illustration of the proposed site layout.

Figure 1. Site Layout

Figure provided by Larson Engineering, Inc dated February 21, 2020.


A.2. Site Conditions and History

Currently, the site exists as an elementary school with associate grass areas and pavements.

Current grades range from 1134.4 to 1135.2 MSL across the proposed building footprint based on our

boring locations and from 1131.9 to 1132.8 across the proposed parking lot based on our boring

locations. Generally, the site is flat.

In the proposed parking lot area on the north side of the school, a house once impacted the site which

since has been demolished. As shown in Photograph 1 below, you will note the location of the house.

Photograph 1. Aerial Photograph of the house on site in April of 2015.

Photograph provided by Google Earth ™ captured on March 3, 2020.

A.3. Purpose

The purpose of our geotechnical evaluation was to characterize subsurface geologic conditions at

selected exploration locations and evaluate their impact on the design and construction of the building

addition and pavement improvements.


A.4. Background Information and Reference Documents

We reviewed the following information:

▪ Preliminary civil drawings prepared by Larson Engineering, Inc and dated February 21, 2020.

▪ Preliminary structural drawings prepared by Sandman Structural Engineers, undated.

▪ Preliminary architectural drawings prepared by HSR Associates, Inc and dated November 4, 2019.

▪ Correspondences with the project team with Nexus Solutions regarding project plans.

▪ Correspondence with Wayne Linderman with Sandman Structural Engineers regarding structural loads.

▪ Surficial Geology of Winona County, County Atlas Series Atlas C-34, Part A-Plate 3, prepared by Lusardi, Adams, and Hobbs in 2014.

▪ Bedrock Geology of Winona County, County Atlas Series Atlas C-34 Part A-Plate 2, prepared by Steenberg in 2014.

▪ Aerial imagery of the site provided by Google Earth ™.

We have described our understanding of the proposed construction and site to the extent others

reported it to us. Depending on the extent of available information, we may have made assumptions

based on our experience with similar projects. If we have not correctly recorded or interpreted the

project details, the project team should notify us. New or changed information could require additional

evaluation, analyses and/or recommendations.

A.5. Scope of Services

We performed our scope of services for the project in accordance with our Proposal to perform a

Geotechnical Evaluation, dated January 28, 2020, and authorized on January 28, 2020. The following list

describes the geotechnical tasks completed in accordance with our authorized scope of services.

▪ Reviewing the background information and reference documents previously cited.


▪ Staking and clearing the exploration location of underground utilities. Nexus Solutions selected and we staked the new exploration locations. We acquired the surface elevations and locations with GPS technology using the State of Minnesota’s permanent GPS base station network. The Soil Boring Location Sketch included in the Appendix shows the approximate locations of the borings.

▪ Performing nine (9) standard penetration test (SPT) borings, denoted as ES-1 to ES-9, to nominal depths of 10 to 20 feet below grade across the site.

▪ Performing laboratory testing on select samples to aid in soil classification and engineering analysis.

▪ A CAD sketch showing project components, limits, and exploration locations.

▪ Logs of the borings describing the materials encountered and presenting the results of our groundwater measurements, laboratory tests, and thickness of pavement and aggregate base material, if applicable.

▪ A summary of the subsurface profile and groundwater conditions.

▪ Discussion identifying the site conditions that will impact structure design and performance, qualifying the nature of their impact, and outlining alternatives for mitigating their impact.

▪ Discussion regarding the reuse of on-site materials during construction and the impact of groundwater on construction.

▪ Recommendations for preparing building addition and pavement subgrades, including excavation support, if applicable, and the selection, placement and compaction of excavation backfill and other structural fill.

▪ Recommended bearing capacity and expected settlement for the design of spread footing foundations.

▪ Providing recommended pavement section thicknesses for pavement reconstruction based on assumed subgrade parameters.

Our scope of services did not include environmental services or testing and our geotechnical personnel

performing this evaluation are not trained to provide environmental services or testing. We can provide

environmental services or testing at your request.


B. Results

B.1. Geologic Overview

The surficial geology consisted of alluvium, glacial till, and bedrock from the Shakopee Formation.

We based the geologic origins used in this report on the soil types, in-situ and laboratory testing, and

available common knowledge of the geological history of the site. Because of the complex depositional

history, geologic origins can be difficult to ascertain. We did not perform a detailed investigation of the

geologic history for the site.

B.2. Boring Results

Table 3 provides a summary of the soil boring results, in the general order we encountered the strata.

Please refer to the Log of Boring sheets in the Appendix for additional details. The Descriptive

Terminology sheets in the Appendix include definitions of abbreviations used in Table X.

Table 3. Subsurface Profile Summary*

Strata

Soil Type - ASTM

Classification

Range of Penetration Resistances Commentary and Details

Pavement section

--- ---

▪ Overall thickness ranges from 8 to 14 inches. ▪ Bituminous thickness 3 to 5 inches. ▪ Suspected Aggregate base is 5 to 9 inches.** ▪ Boring ES-9 encountered two pavement sections

due to prior overlay.

Topsoil fill CL 10 blows per foot

(BPF)

▪ Encountered in borings ES-6 and ES-7 ▪ Predominantly CL. ▪ Generally wet when thawed. ▪ Black ▪ Contained roots. ▪ Thicknesses at boring locations varied from 11

inches to 4 feet. ▪ Moisture condition generally (dry, moist or wet).

Fill SM, SC, CL 3 to 42 BPF

▪ Encountered in all borings except ES-2. ▪ General penetration resistance of 4 to 10 BPF.

Frost appeared to influence samples pertaining to the higher blow counts.

▪ Moisture condition generally moist. ▪ Generally dark brown, and brown.


Strata

Soil Type - ASTM

Classification

Range of Penetration Resistances Commentary and Details

▪ Extended at boring locations varied to a depth of 4 to 7 feet.

▪ Borings ES-7 appeared to contain organics.

Alluvial SP-SM, SM 4 to 11 BPF (sands)

▪ Encountered in borings ES-2 and ES-3. ▪ General penetration resistance of 4 to 8 BPF in

the sandy soil indicating a relative density of very loose to loose.

▪ Moisture condition generally moist. ▪ Generally light brown and brown. ▪ Varying amounts of gravel.

Glacial deposits

SM 5 to 6 BPF

▪ Glacial Till deposits. ▪ Encountered in borings ES-2, ES-3, ES-5, ES-8 and

ES-9. ▪ General penetration resistance of 5 to 6 BPF in

the sandy soil indicating a relative density of loose.

▪ General penetration resistance of 4 to 10 BPF in the clayey soil indicating a consistency of soft to stiff.

▪ Moisture condition generally moist to wet. ▪ Variable amounts of gravel; may contain cobbles

and boulders. ▪

SC, CL 4 to 14 BPF

Bedrock Dolostone

6 BPF to 50 blows for

1 inch of penetration

▪ Encountered in all borings, but sample collected in all but borings ES-2, and ES-3

▪ Top of bedrock varied from elevation 1116.7 (ES-5) to 1130.9 (ES-1).

▪ Retrieved in split-spoon sampler as GM, SM, ML, and CL.

▪ Generally highly weathered to decomposed.

*Abbreviations defined in the attached Descriptive Terminology sheets.

**Noted as suspected aggregate base because no gradation was tested.

For simplicity in this report, we define existing fill to mean existing, uncontrolled or undocumented fill.


B.3. Bedrock

Our borings extended to the Shakopee Formation Dolostone. In most areas where our borings

encountered weathered bedrock, our hollow-stem auger was able to extend into the dolostone

approximately 2.1 to 4.5 feet before meeting auger refusal, however, this is not case in every instance.

This indicates a variable and highly weathered bedrock surface.

Table 4 below summarizes the depths and corresponding elevations at which bedrock was encountered

in our borings. We have assumed the borings that met refusal were terminated on intact Shakopee

Formation in all areas applicable, but this could not be confirmed in every case. However, auger refusal

can occur on more resistant layers or boulders within the weathered bedrock zone such that the

presence of intact bedrock can only be verified by performing rock cores.

Table 4. Approximate Bedrock Elevations

Location Surface

Elevation

Approximate Top of Bedrock Auger or Split-Spoon Sampler

Refusal

Depth (ft)

Elevation Formation Depth

(ft) Elevation

ES-1 1134.9 4.0 1130.9 Shakopee 8.5 1126.4

ES-2 1134.4 20.1* 1114.3 Shakopee 20.1 1114.3

ES-3 1134.4 13.1* 1121.3 Shakopee 13.1 1121.3

ES-4 1135.2 6.0 1129.1 Shakopee 9.2 1125.9

ES-5 1134.7 18.0 1116.7 Shakopee 18.1 1116.6

ES-6 1132.8 7.0 1125.8 Shakopee 10.6 1122.2

ES-7 1132.0 9.0 1123.0 Shakopee 11.0 1121.0

ES-8 1131.9 9.0 1129.9 Shakopee ---** ---

ES-9 1132.5 7.0 1125.5 Shakopee 9.1 1123.4

*Assumed top of bedrock depth, however a sample was unable to be recovered in the split-spoon sampler. **Did not meet refusal as the planned boring termination depth was encountered prior.


B.4. Groundwater

Table 5 summarizes the depths where we observed groundwater; the attached Log of Boring sheets in

the Appendix also include this information and additional details.

Table 5. Groundwater Summary

Location Surface

Elevation

Estimated Depth to Groundwater

(ft)

Corresponding Groundwater Elevation

(ft)

ES-1 1134.9 --- ---

ES-2 1134.4 15 1119 1/2

ES-3 1134.4 --- ---

ES-4 1135.2 --- ---

ES-5 1134.7 15 1119 1/2

ES-6 1132.8 --- ---

ES-7 1132.0 --- ---

ES-8 1131.9 --- ---

ES-9 1132.5 --- ---

At the time of our observation, the groundwater surface elevation appeared to be about elevation 1119

1/2 feet. It is anticipated that groundwater will not be encountered during excavation activities.

B.5. Laboratory Test Results

The boring logs show the results of laboratory testing we performed, next to the tested sample depth.

The moisture content of the soils expected to be excavated during construction activities varied from

approximately 7 to 19 percent, indicating that the material was below to near its probable optimum

moisture content.


Table 6 presents the results of our laboratory tests.

Table 6. Laboratory Classification Test Results

Location

Sample Depth

(ft) Classification

Moisture Content (w, %)

Percent Passing a

#200 Sieve

ES-1 3 CL (FILL) 17 ---

ES-2 3 SM 9 25

ES-3 3 SM (FILL) 9 ---

ES-3 5 CL (FILL) 18 ---

ES-4 1 1/2 SC (FILL) 9 ---

ES-5 3 SM (FILL) 7 ---

ES-5 7 1/2 CL 32 ---

ES-6 2 1/2 SC (FILL) 15 34

ES-7 2 1/2 CL (FILL) 19 ---

ES-8 2 1/2 SC (FILL) 14 ---

ES-9 2 1/2 SC (FILL) 15 ---

C. Recommendations

C.1. Design and Construction Discussion

From a design and construction perspective, it is our opinion that the proposed building can be

supported on traditional spread-footing type foundations. However, the following should be considered

during design and construction:


▪ The existing, uncontrolled fill, being poorly compacted is unsuitable for building support. All

existing fill soils should be removed below the building and associated oversize areas.

▪ The excavated material can be re-used as structural fill provided it is evaluated prior to

placement and meets the criteria within this report.

▪ Due to the shallow bedrock near the areas of the existing building, constructing grade beams

on helical piles should not be considered due to the lack of embedment depth.

▪ Depth of bedrock should be confirmed where the new footings are planned near the existing

foundations.

▪ We anticipate the former house that was located in the area of the north parking lot will

contain debris from demolition. We recommend all debris be removed under the parking

lot.

C.2. Site Grading and Subgrade Preparation

C.2.a. Building Subgrade Excavations

We recommend removing the existing pavement section, fill, and unsuitable materials below the

proposed building footprint and their oversize areas. Based on the borings, we do anticipate soil

corrections below the proposed footing elevations in areas of the building pad. We also recommend

having a geotechnical engineer, or an engineering technician working under the direction of a

geotechnical engineer, (geotechnical representative) evaluate the suitability of exposed subgrade soils to

support the proposed structure.

Table 7 shows the anticipated excavation depths and bottom elevations for each of the borings.


Table 7. Building Excavation Depths

Location

Approximate Surface Elevation

(ft)

Anticipated Excavation Depth

(ft)

Anticipated Bottom Elevation

(ft)

Anticipated Depth Below Floor (FFE =

1135 MSL) (ft)

ES-1 1134.9 4 1131 4

ES-2 1134.4 1 1133 1/2 1 1/2

ES-3 1134.4 7 1127 1/2 7 1/2

ES-4 1135.2 6 1129 6

ES-5 1134.7 7 1127 1/2 7 1/2

Excavation depths will vary between the borings. Portions of the excavations may also extend deeper

than indicated by the borings. A geotechnical representative should observe the excavations to make the

necessary field judgments regarding the suitability of the exposed soils, particulary during the excavation

near the existing foundation to confirm whether the existing footings are bearing on bedrock as well as if

the new footings will also bear on bedrock where tying into the existing foundation.

Prior to the placement of engineered fill or footings, we recommend surface compacting the exposed

soils in the bottoms of the excavations with a minimum of five passes by a large (minimum diameter of

3 1/2 feet), smooth-drum compactor to a minimum of 98 percent of the standard Proctor. Areas that

yield or pump during surface compaction may require additional subcutting.

C.2.b. Excavation Oversizing

When removing unsuitable materials below structures or pavements, we recommend the excavation

extend outward and downward at a slope of 1H:1V (horizontal:vertical) or flatter. See Figure 2 for an

illustration of excavation oversizing.


Figure 2. Generalized Illustration of Oversizing

C.2.c. Excavated Slopes

Based on the borings, we anticipate on-site soils in excavations will consist of previously disturbed fill

soils. These soils are typically considered Type C Soil under OSHA (Occupational Safety and Health

Administration) guidelines. OSHA guidelines indicate unsupported excavations in Type C soils should have

a gradient no steeper than 1 1/2H:1V. Slopes constructed in this manner may still exhibit surface

sloughing. OSHA requires an engineer to evaluate slopes or excavations over 20 feet in depth.

An OSHA-approved qualified person should review the soil classification in the field. Excavations must

comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P, “Excavations and Trenches.” This

document states excavation safety is the responsibility of the contractor. The project specifications

should reference these OSHA requirements.

1. Engineered fill as defined in C.3 2. Excavation oversizing minimum of 1 to 1

(horizontal to vertical) slope or flatter 3. Engineered fill as required to meet

pavement support or landscaping requirements as defined in C.3

4. Backslope to OSHA requirements


C.2.d. Excavation Dewatering

Although not anticipated, we recommend removing groundwater from the excavations. Project planning

should include temporary sumps and pumps for excavations.

C.2.e. Pavement and Exterior Slab Subgrade Preparation

We recommend the following steps for pavement and exterior slab subgrade preparation, understanding

the site will have a grade change of 1-foot or less. Note that project planning may need to require

additional subcuts to limit frost heave.

1. Surface compact the subgrade with a self-propelled vibratory sheep foot compactor.

2. Have a geotechnical representative observe the excavated subgrade to evaluate if additional

subgrade improvements are necessary.

3. Slope subgrade soils to areas of sand or drain tile to allow the removal of accumulating

water.

4. Place pavement engineered fill to grade and compact in accordance with Section C.2.g to

bottom of pavement and exterior slab section. See Section C.6 for additional considerations

related to frost heave.

5. Proofroll the pavement or exterior slab subgrade as described in Section C.2.f.

To improve long-term pavement performance, we recommend incorporating 1-foot of sand engineered

fill in paved areas, in addition to the recommendations above, as a sand subbase.

Section C.7.a provides recommended pavement design sections with and without the sand subbase.

Note, we recommend sloping subgrade soils to promote drainage and removal of accumulated water.

Note, we recommend sloping subgrade soils to promote drainage and removal of accumulated water

C.2.f. Pavement Subgrade Proofroll

After preparing the subgrade as described above and prior to the placement of the aggregate base, we

recommend proofrolling the subgrade soils with a fully loaded tandem-axle truck. We also recommend

having a geotechnical representative observe the proofroll. Areas that fail the proofroll likely indicate

soft or weak areas that will require additional soil correction work to support pavements.

The contractor should correct areas that display excessive yielding or rutting during the proofroll, as

determined by the geotechnical representative.


Possible options for subgrade correction include moisture conditioning and recompaction, subcutting

and replacement with soil or crushed aggregate, chemical stabilization and/or geotextiles. We

recommend performing a second proofroll after the aggregate base material is in place, and prior to

placing bituminous or concrete pavement.

C.2.g. Engineered Fill Materials and Compaction

Table 8 below contains our recommendations for engineered fill materials.

Table 8. Engineered Fill Materials*

Locations To Be Used Engineered Fill Classification

Possible Soil Type

Descriptions Gradation Additional

Requirements

▪ Below foundations ▪ Below interior

slabs Structural fill

SP, SP-SM, SM, SC, CL

100% passing 2-inch sieve < 10% passing the #200 sieve

< 2% Organic Content (OC)

▪ Non-frost-susceptible

▪ Free-draining ▪ Non-frost-

susceptible fill GP, GW, SP, SW

100% passing 1-inch sieve < 50% passing #40 sieve < 5% passing #200 sieve

< 2% OC

Pavements Pavement fill SP, SM, SC, CL 100% passing 3-inch sieve < 2% OC PI < 20%

Below landscaped surfaces, where subsidence is not a concern

Non-structural fill

--- 100% passing 6-inch sieve < 10% OC

* More select soils comprised of coarse sands with < 5% passing #200 sieve may be needed to accommodate work occurring in periods of wet or freezing weather.

We recommend spreading engineered fill in loose lifts of approximately 8 inches thick. We recommend

compacting engineered fill in accordance with the criteria presented below in Table 9. The project

documents should specify relative compaction of engineered fill, based on the structure located above

the engineered fill, and vertical proximity to that structure.


Table 9. Compaction Recommendations Summary

Reference

Relative Compaction, percent

(ASTM D698 – Standard Proctor)

Moisture Content Variance from Optimum, percentage points

< 12% Passing #200 Sieve (typically SP, SP-SM)

> 12% Passing #200 Sieve (typically CL, SC, ML, SM)

Below foundations and oversizing zones

98 -4 to +2 -1 to +3

Below interior slabs 98 -4 to +2 -1 to +3

Within 3 feet of pavement subgrade

100 -4 to +2 -2 to +1

More than 3 feet below pavement subgrade

95 -4 to +2 ±3

Below landscaped surfaces

90 ±5 ±5

*Increase compaction requirement to meet compaction required for structure supported by this engineered fill.

The project documents should not allow the contractor to use frozen material as engineered fill or to

place engineered fill on frozen material. Frost should not penetrate under foundations during

construction.

We recommend performing density tests in engineered fill to evaluate if the contractors are effectively

compacting the soil and meeting project requirements.

C.2.h. Special Inspections of Soils

We recommend including the site grading and placement of engineered fill within the building pad under

the requirements of Special Inspections, as provided in Chapter 17 of the International Building Code,

which is part of the Minnesota State Building Code. Special Inspection requires observation of soil

conditions below engineered fill or footings, evaluations to determine if excavations extend to the

anticipated soils, and if engineered fill materials meet requirements for type of engineered fill and

compaction condition of engineered fill. A licensed geotechnical engineer should direct the Special

Inspections of site grading and engineered fill placement.

The purpose of these Special Inspections is to evaluate whether the work is in accordance with the

approved Geotechnical Report for the project. Special Inspections should include evaluation of the

subgrade, observing preparation of the subgrade (surface compaction or dewatering, excavation

oversizing, placement procedures and materials used for engineered fill, etc.) and compaction testing of

the engineered fill.


C.3. Spread Footings

Table 9 below contains our recommended parameters for foundation design.

Table 9. Recommended Spread Footing Design Parameters

Item Description

Maximum net allowable bearing pressure (psf) 4,000 (on engineered fill or native soil)

10,000 (on Shakopee Formation Dolostone)

Minimum factor of safety for bearing capacity failure 3.0

Minimum width (inches) 18

Minimum embedment below final exterior grade for heated structures (inches)

42

Minimum embedment below final exterior grade for unheated structures or for footings not protected from

freezing temperatures during construction (inches) 60

Total estimated settlement (inches) Less than 1 inch

Differential settlement Typically about 1/2 of total settlement*

* Actual differential settlement amounts will depend on final loads and foundation layout. When tying into the existing buildings, the total settlement of this new building will be differential to the existing building. We can evaluate differential settlement based on final foundation plans and loadings.

C.4. Construction Adjacent to Existing Structures

C.4.a. Excavations

Excavations for the building addition may extend near or below existing footing grades. To reduce the

risk of undermining the existing foundations, we recommend starting the excavation away from the

exterior footing 2 feet horizontally then follow a 1H:1V excavation slope down to the bottom of the soil

correction.

After reaching the design depth, a geotechnical representative should observe the excavation bottom to

evaluate the suitability of the soils near the existing foundation for support of the new floor slab and

foundation. We recommend contacting us if excavations need to extend beyond the limits described

above, as this may warrant additional construction such as ground improvement, retention or

underpinning.


During construction, the contractor should monitor the slope and structure for movement. We also

recommend protecting the slope from disturbance, such as precipitation, runoff or sloughing. The project

team should establish threshold limits of movement and required action, if the movement exceeds the

limits.

C.4.b. Settlement

Due to the existing building not likely settling with the proposed addition, approximately 1/3 inch of

differential settlement could occur between the existing building and the addition. To accommodate this

settlement, we recommend connecting the addition to the building later in the construction process

after most of the dead load is in place on the addition. We also recommend installing expansion joints

between the existing building and the addition or designing the structure to accommodate differential

movement.

C.5. Interior Slabs

Leaving the existing fill in-place beneath the slab could be considered, provided the owner accepts the

risk of potential settlement.

C.5.a. Subgrade Modulus

The anticipated floor subgrade will consist of clayey, silty, and sandy fill material. We recommend using a

modulus of subgrade reaction, k, of 100 pounds per square inch per inch of deflection (pci) to design the

slabs. If the slab design requires placing 6 inches of compacted crushed aggregate base immediately

below the slab, the slab design may increase the k-value by 50 pci. We recommend that the aggregate

base materials be free of bituminous. In addition to improving the modulus of subgrade reaction, an

aggregate base facilitates construction activities and is less weather sensitive.

C.5.b. Moisture Vapor Protection

Excess transmission of water vapor could cause floor dampness, certain types of floor bonding agents to

separate, or mold to form under floor coverings. If project planning includes using floor coverings or

coatings, we recommend placing a vapor retarder or vapor barrier immediately beneath the slab.

We also recommend consulting with floor covering manufacturers regarding the appropriate type, use

and installation of the vapor retarder or barrier to preserve warranty assurances.


C.6. Frost Protection

C.6.a. General

Clayey soil will underlie all or some of the exterior slabs, as well as pavements. We consider clays to be

moderately to highly frost susceptible. Soils of this type can retain moisture and heave upon freezing. In

general, this characteristic is not an issue unless these soils become saturated, due to surface runoff or

infiltration, or are excessively wet in situ. Once frozen, unfavorable amounts of general and isolated

heaving of the soils and the surface structures supported on them could develop. This type of heaving

could affect design drainage patterns and the performance of exterior slabs and pavements, as well as

any isolated exterior footings and piers.

Note that general runoff and infiltration from precipitation are not the only sources of water that can

saturate subgrade soils and contribute to frost heave. Roof drainage and irrigation of landscaped areas in

close proximity to exterior slabs, pavements, and isolated footings and piers, contribute as well.

C.6.b. Frost Heave Mitigation

To address most of the heave related issues, we recommend setting general site grades and grades for

exterior surface features to direct surface drainage away from buildings, across large paved areas and

away from walkways. Such grading will limit the potential for saturation of the subgrade and subsequent

heaving. General grades should also have enough “slope” to tolerate potential larger areas of heave,

which may not fully settle after thawing.

Even small amounts of frost-related differential movement at walkway joints or cracks can create

tripping hazards. Project planning can explore several subgrade improvement options to address this

condition.

One of the more conservative subgrade improvement options to mitigate potential heave is removing

any frost-susceptible soils present below the exterior slab areas down to a minimum depth of 4 feet

below subgrade elevations. We recommend filling the resulting excavation with non-frost-susceptible fill.

We also recommend sloping the bottom of the excavation toward one or more collection points to

remove any water entering the engineered fill. This approach will not be effective in controlling frost

heave without removing the water.

An important geometric aspect of the excavation and replacement approach described above is sloping

the banks of the excavations to create a more gradual transition between the unexcavated soils

considered frost susceptible and the engineered fill in the excavated area, which is not frost susceptible.


The slope allows attenuation of differential movement that may occur along the excavation boundary.

We recommend slopes that are 3H:1V, or flatter, along transitions between frost-susceptible and non-

frost-susceptible soils.

Figure 3 shows an illustration summarizing some of the recommendations.

Figure 3. Frost Protection Geometry Illustration

Another option is to limit frost heave in critical areas, such as doorways and entrances, via frost-depth

footings or localized excavations with sloped transitions between frost-susceptible and non-frost-

susceptible soils, as described above.

Over the life of slabs and pavements, cracks will develop and joints will open up, which will expose the

subgrade and allow water to enter from the surface and either saturate or perch atop the subgrade soils.

This water intrusion increases the potential for frost heave or moisture-related distress near the crack or

joint. Therefore, we recommend implementing a detailed maintenance program to seal and/or fill any

cracks and joints. The maintenance program should give special attention to areas where dissimilar

materials abut one another, where construction joints occur and where shrinkage cracks develop.


C.7. Pavements and Exterior Slabs

C.7.a. Design Sections

Our scope of services for this project did not include laboratory tests on subgrade soils to determine an

R-value for pavement design. Based on our experience with similar clayey soils anticipated at the

pavement subgrade elevation, we recommend pavement design assume an R-value of 10. Note the

contractor may need to perform limited removal of unsuitable or less suitable soils to achieve this value.

Table 10 provides recommended pavement sections, based on the soils support and traffic loads.

Table 10. Recommended Bituminous Pavement Sections

Use Light Duty Light Duty with Sand

Subbase

Minimum asphalt thickness (inches)

4 3 1/2

Minimum aggregate base thickness

(inches) 9 8

Minimum granular subbase

--- 12

C.7.b. Bituminous Pavement Materials

Appropriate mix designs are critical to the performance of flexible pavements. We can provide

recommendations for pavement material selection during final pavement design.

C.7.c. Subgrade Drainage

We recommend installing perforated drainpipes throughout pavement areas at low points, around catch

basins, and behind curb in landscaped areas. We also recommend installing drainpipes along pavement

and exterior slab edges where exterior grades promote drainage toward those edge areas. The

contractor should place drainpipes in small trenches, extended at least 8 inches below the granular

subbase layer, or below the aggregate base material where no subbase is present.

C.7.d. Performance and Maintenance

We based the above pavement designs on a 20-year performance life for bituminous. This is the amount

of time before we anticipate the pavement will require reconstruction. This performance life assumes

routine maintenance, such as seal coating and crack sealing. The actual pavement life will vary depending

on variations in weather, traffic conditions and maintenance.


It is common to place the non-wear course of bituminous and then delay placement of wear course. For

this situation, we recommend evaluating if the reduced pavement section will have sufficient structure to

support construction traffic.

Many conditions affect the overall performance of the exterior slabs and pavements. Some of these

conditions include the environment, loading conditions and the level of ongoing maintenance. With

regard to bituminous pavements in particular, it is common to have thermal cracking develop within the

first few years of placement, and continue throughout the life of the pavement. We recommend

developing a regular maintenance plan for filling cracks in exterior slabs and pavements to lessen the

potential impacts for cold weather distress due to frost heave or warm weather distress due to wetting

and softening of the subgrade.

C.8. Utilities

C.8.a. Subgrade Stabilization

Earthwork activities associated with utility installations located inside the building area should adhere to

the recommendations in Section C.2.

For exterior utilities, we anticipate the soils at typical invert elevations will be suitable for utility support.

However, if construction encounters unfavorable conditions such as soft clay, organic soils or perched

water at invert grades, the unsuitable soils may require some additional subcutting and replacement

with sand or crushed rock to prepare a proper subgrade for pipe support. Project design and construction

should not place utilities within the 1H:1V oversizing of foundations.

It is possible bedrock is encountered at typical invert elevations. The portions of the bedrock penetrable

with our hollow-stem auger are highly weathered to decomposed. Due to the bedrock formation type, it

should not be assumed that the bedrock can be dislodged and removed using large backhoes equipped

with toothed buckets or large dozers equipped with ripping teeth. Portions of the bedrock may require

alternative excavation methods such as pneumatic hammers.

If bedrock is encountered during installation of utilities, we recommend an overcut of 1/2 to 1-foot take

placed and backfilled with a crushed rock for uniformity.

C.8.b. Corrosion Potential

Based on our experience, the soils encountered by the borings are moderately corrosive to metallic

conduits, but only marginally corrosive to concrete.


We recommend specifying non-corrosive materials or providing corrosion protection, unless project

planning chooses to perform additional tests to demonstrate the soils are not corrosive.

C.9. Equipment Support

The recommendations included in the report may not be applicable to equipment used for the

construction and maintenance of this project. We recommend evaluating subgrade conditions in areas of

shoring, scaffolding, cranes, pumps, lifts and other construction equipment prior to mobilization to

determine if the exposed materials are suitable for equipment support, or require some form of

subgrade improvement. We also recommend project planning consider the effect that loads applied by

such equipment may have on structures they bear on or surcharge – including pavements, buried

utilities, below-grade walls, etc. We can assist you in this evaluation.

D. Procedures

D.1. Penetration Test Borings

We drilled the penetration test borings with an ATV-mounted core and auger drill equipped with hollow-

stem auger. We performed the borings in general accordance with ASTM D6151 taking penetration test

samples at continuous, and 2 1/2- or 5-foot intervals in general accordance to ASTM D1586. The boring

logs show the actual sample intervals and corresponding depths.

We sealed penetration test boreholes meeting the Minnesota Department of Health (MDH)

Environmental Borehole criteria with an MDH-approved grout. We will forward/forwarded a sealing

record (or sealing records) for those boreholes to the Minnesota Department of Health Well

Management Section. A copy of the sealing record follows (or copies of the sealing records follow) the

Log of Boring sheets in the Appendix.

D.2. Exploration Logs

D.2.a. Log of Boring Sheets

The Appendix includes Log of Boring sheets for our penetration test borings. The logs identify and

describe the penetrated geologic materials, and present the results of penetration resistance and other

in-situ tests performed.


The logs also present the results of laboratory tests performed on penetration test samples, and

groundwater measurements. The Appendix also includes a Fence Diagram intended to provide a

summarized cross-sectional view of the soil profile across the site.

We inferred strata boundaries from changes in the penetration test samples and the auger cuttings.

Because we did not perform continuous sampling, the strata boundary depths are only approximate. The

boundary depths likely vary away from the boring locations, and the boundaries themselves may occur as

gradual rather than abrupt transitions.

D.2.b. Geologic Origins

We assigned geologic origins to the materials shown on the logs and referenced within this report, based

on: (1) a review of the background information and reference documents cited above, (2) visual

classification of the various geologic material samples retrieved during the course of our subsurface

exploration, (3) penetration resistance and other in-situ testing performed for the project, (4) laboratory

test results, and (5) available common knowledge of the geologic processes and environments that have

impacted the site and surrounding area in the past.

D.3. Material Classification and Testing

D.3.a. Visual and Manual Classification

We visually and manually classified the geologic materials encountered based on ASTM D2488. When we

performed laboratory classification tests, we used the results to classify the geologic materials in

accordance with ASTM D2487. The Appendix includes a chart explaining the classification system we

used.

D.3.b. Laboratory Testing

The exploration logs in the Appendix note most of the results of the laboratory tests performed on

geologic material samples. The remaining laboratory test results follow the exploration logs. We

performed the tests in general accordance with ASTM or AASHTO procedures.

D.4. Groundwater Measurements

The drillers checked for groundwater while advancing the penetration test borings, and again after auger

withdrawal. We then filled the boreholes or allowed them to remain open for an extended period of

observation, as noted on the boring logs.


E. Qualifications

E.1. Variations in Subsurface Conditions

E.1.a. Material Strata

We developed our evaluation, analyses and recommendations from a limited amount of site and

subsurface information. It is not standard engineering practice to retrieve material samples from

exploration locations continuously with depth. Therefore, we must infer strata boundaries and

thicknesses to some extent. Strata boundaries may also be gradual transitions, and project planning

should expect the strata to vary in depth, elevation and thickness, away from the exploration locations.

Variations in subsurface conditions present between exploration locations may not be revealed until

performing additional exploration work, or starting construction. If future activity for this project reveals

any such variations, you should notify us so that we may reevaluate our recommendations. Such

variations could increase construction costs, and we recommend including a contingency to

accommodate them.

E.1.b. Groundwater Levels

We made groundwater measurements under the conditions reported herein and shown on the

exploration logs, and interpreted in the text of this report. Note that the observation periods were

relatively short, and project planning can expect groundwater levels to fluctuate in response to rainfall,

flooding, irrigation, seasonal freezing and thawing, surface drainage modifications and other seasonal

and annual factors.

E.2. Continuity of Professional Responsibility

E.2.a. Plan Review

We based this report on a limited amount of information, and we made a number of assumptions to help

us develop our recommendations. We should be retained to review the geotechnical aspects of the

designs and specifications. This review will allow us to evaluate whether we anticipated the design

correctly, if any design changes affect the validity of our recommendations, and if the design and

specifications correctly interpret and implement our recommendations.


E.2.b. Construction Observations and Testing

We recommend retaining us to perform the required observations and testing during construction as

part of the ongoing geotechnical evaluation. This will allow us to correlate the subsurface conditions

exposed during construction with those encountered by the borings and provide professional continuity

from the design phase to the construction phase. If we do not perform observations and testing during

construction, it becomes the responsibility of others to validate the assumption made during the

preparation of this report and to accept the construction-related geotechnical engineer-of-record

responsibilities.

E.3. Use of Report

This report is for the exclusive use of the addressed parties. Without written approval, we assume no

responsibility to other parties regarding this report. Our evaluation, analyses and recommendations may

not be appropriate for other parties or projects.

E.4. Standard of Care

In performing its services, Braun Intertec used that degree of care and skill ordinarily exercised under

similar circumstances by reputable members of its profession currently practicing in the same locality.

No warranty, express or implied, is made.

Appendix

CBurkeText Box925 Church Ave

1136 1136

1131 1131

1126 1126

1121 1121

1116 1116

1114.00

Legend KeyAsphalt

Aggreg…

Fill

SM

Dolostone

SP-SM

CL

SC

West to East across Building Pad

Project ID:Vert. Scale:Hor. Scale:Date:

Fence DiagramB2001024 Geotechnical Evalua on1"= xxx' St. Charles School District Referendum ProjectsNTS 925 Church Avenue03-05-2020 St. Charles, Minnesota

WL0.31.0

2.0

4.0

8.5

ES-1

N

20

9

14

REF

WL0.30.7

4.0

6.0

9.2ES

-4

N

53

12

4

REF

REF

WL0.30.9

2.0

4.0

7.0

8.0

9.0

13.1

ES-3

N

34

5

9

4

7

REF

WL0.30.9

4.0

7.0

9.0

12.0

14.0

20.1

ES-2

N

22

7

8

5

4

6

5

REF

WL0.31.0

7.0

12.0

18.018.1

ES-5

N

27

4

4

8

4

6

5

REF

Elev./Depth

ft

1134.70.3

1133.91.0

1132.92.0

1130.94.0

1126.48.5

Wat

erLe

vel Description of Materials

(Soil-ASTM D2488 or 2487; Rock-USACE EM 1110-1-2908)

BITUMINOUS, 3 inches of Bituminous pavementAGGREGATE, 9 inches of Suspected Aggregate BaseFILL: SANDY LEAN CLAY with