Attachment 3 - Straits SP Geotechnical Report 10-22-19.pdf

October 22, 2019

Nowak & Fraus Engineers

46777 Woodward Avenue

Pontiac, Michigan 48342

Attention: Mr. Steven Sutton

Regarding: Straits State Park Bathroom & Shower Project

720 Church Street

St. Ignace, Chippewa County, Michigan

Project No. 2019.1246

Dear Mr. Sutton:

Soils & Structures is pleased to present the report of the geotechnical investigation for the above referenced project.

The investigation included two (2) test borings drilled to depths of 10.0 and 13.5 feet in accordance with ASTM D 1586 procedures. Two test borings performed in 2003 for previous projects in the area of the current project were also utilized for this investigation.

The report, test boring location plan and test boring logs are enclosed. The report provides recommendations for site preparation, spread foundations, fill, floors and pavement.

We appreciate the opportunity to be of service to you. If you have a question concerning the report please contact our office.

Sincerely, Soils & Structures, Inc.

David W. Hohmeyer, P.E.

DWH/dh

File No. 2019.1246

Table of Contents

Page

Location of Soil Investigation

Purpose of Investigation

Design Information

Tests Performed

Description of Soil

Description of Groundwater Conditions

Description of Site

Settlement

Recommendations

Building Pad & Site Preparation

Foundations

Floors

Lateral Earth Pressure

Excavations

Fill

Groundwater Management

Hot Mix Asphalt (HMA) Pavement

Concrete Pavement

Quality Control Testing

General Conditions & Reliance

Appendix

Test Boring Location Plan

General Soil Profile

Test Boring Logs

Laboratory Tests

General Soil Information

Page – Straits State Park

St. Ignace, Chippewa County, Chippewa County, Michigan

October 22, 2019 - Project No. 2019.1246

Location of Soil Investigation

The soil investigation was located at the Straits State Park at 720 Church Street in St. Ignace, Chippewa County, Michigan.

Purpose of Investigation

The purpose of the investigation is to provide soil related recommendations for two building renovations or replacements and pavement.

Design Information

The buildings will be a one-story structures with an area of less than 2500 square feet. The structures are anticipated to be either wood stud or masonry walls. The floor will be a slab on grade.

The maximum axial column load is anticipated to be less than 25,000 pounds. The maximum of wall load is anticipated to be less than 3000 pounds per linear foot. The floor live load used for design is are anticipated to be 40 pounds per square foot. Allowable settlements of 0.6 inches for total settlement and 0.4 inches for differential settlement are assumed.

The floor elevation is anticipated to match the existing floor levels. The thickness of fill reuired below the buildings is anticipated to be less than 1.0 feet. The fill required for this project is anticipated to be obtained off site from a source still to be determined.

The maximum excavation depth is anticipated to be less 4.0 feet or less. The excavation of greatest depth will be for the construction of foundations and utilities.

The pavement is assumed to be subjected to primarily automobile traffic with only occasional truck traffic. An Equivalent Axle Load (EAL) of 5000 and a service life of twenty years were assumed for the pavement subgrade recommendations. The subgrade is assumed to be prepared as recommended in this report.

Tests Performed

Two test borings were drilled to depths of 10.0 and 13.5 feet in accordance with ASTM D

1586 procedures at approximately locations determined jointly by Nowak & Fraus Engineers and Soils & Structures. The ASTM D 1586 standard describes the procedure for testing the soil and is included in the appendix. An automatic hammer was used to obtain the soil samples.

Two test borings performed in 2003 for previous projects involving these buildings were utilized for this investigation. These test borings were performed in accordance with the ASTM

D 1586 Standard. The depth of the 2003 test borings is 15.0 feet.

The test boring locations and the surface elevations at the test boring locations were obtained with a level using standard surveying methods. Surface elevations at the test boring locations and additional points of reference were obtained with a Global Navigation Satellite System

(GNSS) Receiver. The receiver was connected to the local MDOT CORS base station. Through this system vertical measurements are obtained and referenced to a U.S. Geological Survey

(USGS) datum. Horizontal measurements are also obtained of the locations which are referenced to a property corner, building corner or other site specific control point. Both the vertical and horizontal measurements have an accuracy of approximately 0.5 inches. The test borings locations and surface elevations are provided in Table One.

Table One: Test Boring Locations and Elevations

Test Boring / Location Elevation

(feet)

Northing

(feet)

Easting

(feet)

Elevation

Point

Description

Test Boring One-2019 683.644 398888.235 26827252.35 Sod

Test Boring Two – 2019 682.252 398858.829 26826935.91 Sod

Test Boring One – 2003 Sod

Test Boring Two – 2003 Sod

Water Fountain Near Test

Boring Two – 2019

683.933

398875.108 26826906.09 Concrete

Base Set Up /VRS1 613.715 398758.676 26831901.06

Base Set Up /VRS2 613.715 398758.676 26831901.06

Soil samples were classified according to the Unified Soil Classification System. This method is a standardized system for classifying soil according to its engineering properties. Please refer to the appendix of this report for the Unified Classification System Chart. The classification is shown in the right hand column of the test boring logs.

The soil strength and the allowable soil bearing value were evaluated using the “N” value. The

“N” value is the number of blows required to drive a soil sampler one foot with a standard 140 pound drop hammer. The sampler is driven a distance of 18.0 inches. The number of blows for each 6.0 inch increment is recorded. The sum of the second and third intervals is the “N” value. The number of blows for each 6.0 inch interval is shown on the test boring logs under the column labeled “Penetration.” The “N” value for each sample is shown in the adjacent column.

Laboratory testing consisted of water content and sieve (particle size) tests. The tests were performed on representative samples of the soil. The tests were performed in accordance with applicable ASTM standards. The sieve test determines the particle distribution which is used to classify the soil and estimate its properties. The water content documents the presence of groundwater in a cohesionless soil.

The U.S. Geological Survey Topographic map and the Quaternary Geology map of Southern

Michigan were reviewed. These maps provide general geological information about the region.

Description of Soil

The general soil profile consists of limestone to a depth of at least 15.0 feet. Topsoil is present at the surface.

The topsoil layer consists of a dark brown clay. The thickness ranges from 9.0 to 10.0 inches.

The limestone is weather and highly fractured. Occasional pockets and seams of clay are present within the limestone. The limestone is silty and has a low and low permeability. The infiltration rate is very low. The “N” Value is very high. For most samples sampler refusal occurred. Sampler refusal is noted by and “N” Value of 100. The limestone will behave as a weak and will provide very high bearing values and will support conventional foundations, slab on grade floors and pavemen.

Description of Groundwater Conditions

Groundwater was not encountered in the test borings. Groundwater may be periodically A water table is present in the sand layer but is below the maximum depth of the test borings of

20.0 feet.

Description of Site

The site is undeveloped and is wooded. The topography is slopes down to the south at a uniform rate. The surface elevation ranges from 625.0 to 630.0 feet.

Photograph #1: View of the area around Test Boring One. The view is to the northwest.

(Project No. 2019.1246, Straits State Park , St. Ignace, Chippewa County, Michigan, September, 2019)

Photograph #2: View of the area around Test Boring Two. The view is to the northwest.

(Project No. 2019.1246, Straits State Park , St. Ignace, Chippewa County, Michigan, September, 2019)

Settlement

The maximum building settlement will be approximately 0.05 to 0.1 inches with spread foundations provided the recommendations in this report are observed. Differential settlement will be approximately three quarters of the maximum value. These levels of settlement should be acceptable for the proposed building.

Recommendations

Building Pad & Pavement Subgrade Preparation

The topsoil should be removed. The topsoil should be removed to the extent that all soil with an organic content of 3.0 percent or greater is removed. Soil containing roots should be removed to the extent that the root content by volume is 5.0 percent or less. All roots over

0.5 inches in diameter should be removed.

Utilities that will be abandoned should be removed.

Proof compaction of the building are is not necessary. Proof compaction will not significantly improve the subgrade.

Fill should be placed over the site as required. The fill should be placed in accordance with the

“Fill” section of this report. The fill should be compacted to 95.0 percent of its maximum density. The soil which will be used for fill should be kept free of topsoil and other organic materials. The existing sand may be used for fill. Compaction tests are recommended to check the compaction of the new fill.

Foundations

Spread foundations are recommended for the proposed buildings. The foundations will bear on weathered limestone or possibly on new fill.

Fill below foundations should be compacted to a density of 95.0 percent of the soil’s maximum density to its full depth. Compaction tests should be performed in the foundation subgrade to verify these levels of compaction. Soil that possesses lower densities should be recompacted.

The recommended cover over exterior foundations is 42 inches for protection against frost heave.

Foundations should not be constructed on frozen soil. During cold weather construction the foundation subgrade and foundations should be protected from freezing with insulated blankets until backfill is placed over both sides of the foundation. Foundations that are damaged by frost heave should be replaced.

The site classification for seismic design is “B” based on the Michigan Building Code. The short period acceleration is 7.7 percent and the long period or one second acceleration is 3.8 percent. The design spectral response acceleration parameters (SD) are 0.089g for the short term response and 0.13g for the one second response.

Foundations may be designed using an allowable soil bearing value of 5000 pounds per square foot for column foundations and 4000 pounds provided the recommendations in this report are observed. A 30 percent increase in these loads may be used for the design of foundations to resist wind and earthquake loads. A minimum foundation width of 16.0 inches is recommended.

Floors

A base of 12.0 inches of clean sand is recommended under the floors. The sand should meet

MDOT Class II specifications. Fill under floors should be compacted as specified in the “Fill” section of this report.

A modulus of subgrade reaction of 300 pounds per inches cubed is recommended for the design of slabs on grade.

Lateral Earth Pressure

Sand should be used as backfill behind retaining and foundation walls. The sand should meet

MDOT Class II specifications. The walls should be designed using a soil density of 120 pounds per cubic foot and a coefficient of active earth pressure of 0.30 for level sand backfill. The equivalent fluid pressure is 36 pounds per cubic foot for level backfill. The effects of any surcharge or sloping backfill should also be included in the design. The passive resistance of the existing sand should be calculated using an earth pressure coefficient of 4.0.

Excavations

The limestone is an OSHA type “B” soils. Excavations should be based on OSHA requirements for a type “B” soil. Based on OSHA requirements a maximum allowable side slope of 34 degrees (1.5H:1V) is recommended for excavations 4.0 to 15.0 feet deep. Excavations less than 4.0 feet deep may have vertical side slopes.

The limestone though weathered and fractured may be difficult to excavate. Equipment used to remove concrete may be required for excavations.

Fill

Fill including the aggregate layers under pavement should be compacted to a density of 95.0 percent of its maximum density. The maximum density should be determined in accordance with the ASTM D 1557 standard. A maximum thickness per layer of 6.0 inches is recommended. The lift thickness may be increased to 12.0 inches if a vibratory roller or loader is used for compaction. Compaction tests are recommended to confirm that the fill is compacted to the required density.

Structural fill should be sand meeting MDOT Class II requirements or ASTM requirements for a SP or SW which are the designations for clean sand. The existing sand meets these requirements and may be used for fill.

Groundwater Management

Dewatering should not be required for the construction of the foundations and utilities. The water table is below the anticipated depth of excavations for this project.

A vapor barrier is recommended under the floor in areas that will be enclosed and heated.

The vapor barrier should consist of a 10 mil polyethylene sheet and should be located immediately below the floor slab. The vapor barrier may be omitted in portions of the buildings that will not be heated.

On site of infiltration is not storm water is not recommended. The limestone is essentially impervious.

Drains around the foundation are recommended. The drains should consist of a 4.0 inch diameter slotted plastic pipe wrapped in filter fabric. Pea gravel should be used for backfill within a 6.0 inch circumference of the drain.

Hot Mix Asphalt (HMA) Pavement

A bituminous thickness of 3.5 inches with 8.0 inch thick base of coarse aggregate and a

12.0 inch thick subbase of fine aggregate is recommended.. The recommended gradation for the coarse aggregate is MDOT 21A or 22A. The recommended gradation for the fine aggregate is MDOT Class II. The bituminous layer should be placed in two lifts. The subgrade should be proof compacted prior to placement of fill, subbase or the base gravel.

The subgrade is recommended to be prepared in accordance with the "Site & Subgrade

Preparation" and “Fill” sections of this report.

The paving contractor should submit the proposed mix designs for review. The bituminous paving mixture should meet and be installed to the following criteria:

Table One: Bituminous Mixture Requirements

Criteria Base Course Wearing Course minimum maximum Minimum Maximum

MDOT Mix Type 4E1 5E1

Lift Thickness (inches) 2.0 1.5

The asphalt grade should be PG 58-28. The base coarse should be compacted to 92.0 percent of the Theoretical Maximum Density (TMD). The paving contractor should submit the proposed mix design for review.

Concrete Pavement

The subgrade should be prepared in accordance with the “Site & Subgrade Pad

Preparation” and “Fill” sections of this report.

A base fine aggregate is recommended below concrete slabs. The recommended fine aggregate is clean sand meeting MDOT Class II specifications. The recommended minimum thickness is 12.0 inches. The existing sand may be left in place and used for the sand base provided it is free of organics, debris/rubble and silt. The pavement subgrade should be proof compacted prior to placement of fill.

A modulus of subgrade reaction of 150 pounds per inches cubed is recommended for the design of concrete pavement provided the recommendations in this report are observed.

The reinforcing should be designed by a structural engineer.

Quality Control Testing

Compaction tests (ASTM D 2922) are recommended to confirm that fill and natural soil are compacted to the specified density. While fill is being placed compaction tests should be performed at the rate of one test per 400 cubic yard of fill and throughout the depth of the fill with a minimum of five tests at each 1.0 foot elevation interval. Compaction tests should be performed under foundations at the rate of one test per 50 linear feet for wall foundations and one test per column foundation. The recommended testing frequency in the floor and pavement subgrade is one test per 2500 square feet. Tests should also be performed in the backfill over foundations and utilities. The maximum density should be determined in accordance with ASTM D 1557 or ASTM D 4253 procedures.

A smooth 0.5 to 0.75 inch diameter rod should be used in conjunction with compaction tests to probe for loose areas under foundations, in fill and under floors.

A dynamic cone should not be substituted for compaction tests for evaluating fill.

Testing should be performed by technicians supervised by a registered geotechnical engineer.

General Conditions & Reliance

The report was prepared in accordance with generally accepted practices of the geotechnical engineering profession. The scope of work consisted of performing two test borings and providing soil related recommendations for the design and construction of two buildings and pavement. The scope of work did not include an environmental study or wetland determination.

The report and the associated test borings were prepared specifically for the previously described project and site. Soils & Structures should be consulted if a significant change in the scope of the project is made.

The test borings represent point information and may not have encountered all of the soil types and materials present on this site. This report does not constitute a guarantee of the soil or groundwater conditions or that the test boring is an exact representation of the soil or groundwater conditions at all points on this site.

The descriptions and recommendations contained in this report are based on an interpretation of the test borings and laboratory tests. The test borings should not be used independently of the report. If soil conditions are encountered which are significantly different from the test borings Soils & Structures should be consulted for additional recommendations.

The report and test borings may be relied upon by Nowak & Fraus Engineers for the design, construction, permitting and financing associated with the construction and or renovations of two building in Straits State Park at 720 Church Street in St. Ignace, Chippewa County, Michigan. The use of the report and test borings by third parties not associated with this project or for other sites has not been agreed upon by Soils & Structures. Soils & Structures does not recommend or consent to third party use or reliance of the report or test borings unless allowed to review the proposed use of these materials. Unless obtained in writing consent to third party use should not be assumed. Third parties using the report or test boring logs do so at their own risk and are offered no guarantee or promise of indemnity.

De pt h

G ra ph ic

Material DescripƟon

TOPSOIL - dark brown clayey

LIMESTONE - extremely compact brown highly fractured (breccia)

CLAY - brown gray silty with limestone LIMESTONE - extremely compact brown highly fractured (breccia)

Ca uƟ on ar y Co nd iƟ on Sa m pl e Ty pe

N um be r

SPT-A

SPT-B

SPT-C

SPT-D

SPT-E

Re co ve ry

RQ

D

Bl ow

Co un ts

N -V al ue

Sh ea r S tr en gt h

(t sf

M oi st ur e

Co nt en t (

5.5

1.4

9.9

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Borehole ID: Test Boring One-2003 Sheet 1 of 1

Project Name: Straits State Park Bathroom and Shower Project Project Number: 2019.1246 Project LocaƟon: Moran Township, Michigan Logged By: B. Fritz Reviewed By:

Client: Nowak & Fraus Engineers Survey Datum: NAD 1983 StatePlane Michigan North Hole Depth: 15.00 Date Started: Feb 27 2003 Completed: Feb 27 2003 Northing: EasƟng: ElevaƟon:

Drilling Method: 3.25" Hollow Stem Auger Ground Water Levels Equipment: Diedrich D-50 At Time of Drilling Feb 27 2003 - Water not encountered Hammer Type: AutomaƟc Hammer End of Drilling Feb 27 2003 - Water not encountered Notes:

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G ra ph ic

Material DescripƟon

CRUSHED LIMESTONE

LIMESTONE - extremely compact gray highly fractured (breccia)

Ca uƟ on ar y Co nd iƟ on Sa m pl e Ty pe

N um be r

SPT-A

SPT-B

SPT-C

SPT-D

SPT-E

Re co ve ry

RQ

D ts

26-50

39-50

N -V al ue

Sh ea r S tr en gt h

(t sf

M oi st ur e

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AƩerberg Limits

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Borehole ID: Test Boring Two-2003 Sheet 1 of 1

Project Name: Straits State Park Bathroom and Shower Project Project Number: 2019.1246 Project LocaƟon: Moran Township, Michigan Logged By: B. Fritz Reviewed By:

Client: Nowak & Fraus Engineers Survey Datum: NAD 1983 StatePlane Michigan North Hole Depth: 15.00 Date Started: Feb 27 2003 Completed: Feb 27 2003 Northing: EasƟng: ElevaƟon:

Drilling Method: 3.25" Hollow Stem Auger Ground Water Levels Equipment: Diedrich D-50 At Time of Drilling Feb 27 2003 - Water not encountered Hammer Type: AutomaƟc Hammer End of Drilling Feb 27 2003 - Water not encountered Notes:

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G ra ph ic

Material DescripƟon

TOPSOIL - (9.0")

LIMESTONE - weather highly fractured silty

LIMESTOME weathered highly fractured silty

Ca uƟ on ar y Co nd iƟ on Sa m pl e Ty pe

N um be r

SPT-A

SPT-B

SPT-C

SPT-D

SPT-E

Re co ve ry

RQ

D ts

12-12-18

11-16-14

7-9-11

39-50

13-50 N

-V al ue

Sh ea r S tr en gt h

(t sf

M oi st ur e

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AƩerberg Limits

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Borehole ID: Test Boring One-2019 Sheet 1 of 1

Project Name: Straits State Park Bathroom and Shower Project Project Number: 2019.1246 Project LocaƟon: Moran Township, Michigan Logged By: B. P Reviewed By: W. Stambaugh Client: Nowak & Fraus Engineers Survey Datum: NAD 1983 StatePlane Michigan North Hole Depth: 13.50 Date Started: Sep 12 2019 Completed: Sep 12 2019 Northing: 398888.2 EasƟng: 26827252.4 ElevaƟon: 683.64 Drilling Method: 3.25" Hollow Stem Auger Ground Water Levels Equipment: Acker Renegade At Time of Drilling Sep 12 2019 - Water not encountered Hammer Type: AutomaƟc Hammer End of Drilling Sep 12 2019 - Water not encountered Notes:

h

G ra ph ic

Material DescripƟon

TOPSOIL - (10.0")

SILT - very sƟī gray sandy and gravelly (limestone), cobbles

LIMESTONE - extremely sƟī gray with sand and gravel

Ca uƟ on ar y Co nd iƟ on Sa m pl e Ty pe

N um be r

SPT-A

SPT-B

SPT-C

SPT-D

Re co ve ry

RQ

D ts

21-19-19

7-20-17

18-50

31-50

N -V al ue

Sh ea r S tr en gt h (t sf

M oi st ur e Co nt en t (

AƩerberg Limits

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Borehole ID: Test Boring Two-2019 Sheet 1 of 1

Project Name: Straits State Park Bathroom and Shower Project Project Number: 2019.1246 Project LocaƟon: Moran Township, Michigan Logged By: B. P Reviewed By: W. Stambaugh Client: Nowak & Fraus Engineers Survey Datum: NAD 1983 StatePlane Michigan North Hole Depth: 10.00 Date Started: Sep 12 2019 Completed: Sep 12 2019 Northing: 398858.8 EasƟng: 26826935.9 ElevaƟon: 682.25 Drilling Method: 3.25" Hollow Stem Auger Ground Water Levels Equipment: Acker Renegade At Time of Drilling Sep 12 2019 - Water not encountered Hammer Type: AutomaƟc Hammer End of Drilling Sep 12 2019 - Water not encountered Notes: