B05 A3-3 221172.00 Rosebud Health Care Facility -- FMG Geotech (FINAL).pdf

FMG ENGINEERING 3700 Sturgis Road • Rapid City, SD • fmgengineering.com • 605-342-4105

Civil Engineering Geotechnical Engineering Materials Testing Laboratory Land Surveying Environmental Services Water Resources

April 5, 2023

Mr. David Martin

Senior Project Manager

Seven Generations Architecture & Engineering dmartin@7genae.com

Re: Geotechnical Evaluation

Rosebud Health Care Facility

Atrium Infill

Rosebud, SD

Dear Mr. Martin:

As requested, we have performed a geotechnical evaluation for the referenced project. The purpose of this evaluation was to identify the subsurface characteristics, suggest suitable foundation systems for the proposed structures and provide the geotechnical design parameters.

INTRODUCTION

We understand the existing open-air, two-story atrium at the entrance of the Rosebud Health care

Facility in Rosebud, South Dakota will be reconstructed as a two-story, two-floor space. The reconstruction will require the addition of framing which will transmit loads to the existing foundation system. Additionally, the existing open-air entrance canopy is proposed to be enclosed.

FMG Engineering was retained by Seven Generations Architecture & Engineering (Seven

Generations) to perform a geotechnical evaluation of the project area. If proposed construction or locations differ significantly from that described herein, our office should be contacted to re-evaluate the recommendations contained in this report.

Field tests were generally accomplished in accordance with current ASTM and AASHTO procedures, where applicable. This report presents geologic logs and a discussion of our field sampling & testing procedures, materials present, and geotechnical recommendations and construction considerations.

FIELD SAMPLING & TESTING PROCEDURES

A total of three boreholes were drilled to identify the subsurface characteristics at the locations shown on Figures 1 and 2. The borings were drilled using hand auger methods. The borehole locations were selected by Seven Generations and were adjusted in the field as necessary by FMG to avoid existing utilities. If, during subsequent planning, the project areas change significantly from that described in this report, we recommend drilling additional boreholes to verify soil conditions in unexplored areas.

Geologic logs of the boreholes were maintained by a field geologist and the materials were classified in accordance with Figure 3. The geologic logs include the depths of the major changes in the character of the subsurface materials, visual description of the materials, field-testing data and

Geotechnical Evaluation

Rosebud Health Care Facility Atrium Infill locations, and groundwater data. The geologic logs and a legend that describes the geologic log symbols and notes are presented as Appendix A.

The geologic logs and related information depict our approximation of the conditions, interfaces, and materials encountered at the specific borehole location and at the time designated on the logs.

Soil conditions at other locations may be different from those encountered at the drilled borehole locations. Also, the passage of time may produce a changed subsurface and/or soil condition. We have extrapolated the data obtained from the boreholes and our conclusions and recommendations assume that the materials encountered are representative of the soils that exist over the site.

Anomalies may be present around the boreholes.

MATERIALS PRESENT

The existing floor system consisted of a 4-inch concrete slab overlying approximately 7 inches of crushed limestone base course with a plastic vapor barrier in between. The subsurface profile encountered consisted of silty sand to poorly graded sand fill material to the total depths explored.

The silty sand to poorly graded sand fill material was found to be pale brown, dry to moist, non-plastic, and medium dense.

A shallow groundwater table was not encountered at the site. However, groundwater presence and levels should be anticipated to vary in response to seasonal changes in precipitation, bedrock fracture patterns, high precipitation events, and snow melt, and may not be accurately delineated within the normal scope of a geotechnical evaluation.

The geologic logs indicate the specific soil characteristics observed throughout the profiles in the borehole advanced within the proposed project alignment.

GEOTECHNICAL CONSIDERATIONS

From our subsurface soil exploration and engineering analysis, we have arrived at the following conclusion and recommendation regarding the proposed reconstruction.

The existing subgrade soils within the atrium footprint are adequate for shallow foundations. We recommend that a net allowable bearing capacity of 2,500 psf be considered when evaluating the existing foundation for additional loading.

The existing subsurface conditions at the entrance canopy are also suitable for shallow foundations designed for an allowable bearing capacity of 2500 psf. The design parameters presented below in

Table 1 should be observed for the existing entrance canopy foundation system.

Geotechnical Evaluation

Rosebud Health Care Facility Atrium Infill

Table 1 – Existing Entrance Canopy Foundation System

Parameter Value

Subgrade Preparation Scarify, moisture condition, and recompact 6” of native soils to provide a uniform surface.

Net Allowable Bearing Capacity (FS=3.0) 2,500 psf

Static/Dynamic Modulus of Subgrade Reaction 200 pci for engineered fill

Frost Penetration Depth 48 inches

Sliding Friction Coefficient 0.42

Passive Earth Pressure 225 psf

CONCLUDING STATEMENT

If any changes in the nature, design or location of the project are planned, the conclusions and recommendations contained in this addendum report shall not be considered valid unless the changes are reviewed, and conclusions of this report modified or verified in writing.

The findings in this letter report were prepared following accepted soil mechanics procedures and practices. We make no other warranty, either implied or expressed. The conclusions of this letter report are based upon the results of the field exploration boring, field tests, and analysis. We have extrapolated the data obtained from the test borehole locations to the surrounding soils. Anomalies can exist around the borings. The data presented on the boring logs represent the conditions as encountered in that particular test hole on the date drilled and logged. If, during planning and construction, conditions are different from those indicated, please notify us so that we can modify the conclusions and recommendations.

We trust this information is sufficient at this time. If you have any questions, or desire any additional information, please call us at your earliest convenience. Thank you for the opportunity to be of service.

Respectfully submitted, FMG, Inc.

John Lucas, P.E. Alex Fisher, P.E.

Enclosures: Figure 1 – Borehole Location Map

Figure 2 – Borehole Location Cross Section

Figure 3 – Soil Classification

Appendix A – Geologic Logs

Drawn By:

Revision / Date

Figure Number:

Sheet Name:

Checked By:

Surveyed By:

Date:

File Number:

Location:

FM

G

E N

G

IN

EE

RI

N G

S tu rg is

R oa d R ap id

C ity

, S D

5.

2.

fm ge ng in ee rin g.

co m A p ri l

XXX

XXX

XXX

XXX

221172

XXX

XXX

Legend

BH#1 Borehole Location

Borehole Location Plan

R o s e b u d

H e a lt h

C a re F a c il it y A tr iu m I n fi ll

R o s e b u d

S o u th D a k o ta

BH-3

BH-1

BH-2

Main Level

Basement Level

BH-2

Drawn By:

Revision / Date

Figure Number:

Sheet Name:

Checked By:

Surveyed By:

Date:

File Number:

Location:

FM

G

E N

G

IN

EE

RI

N G

S tu rg is

R oa d R ap id

C ity

, S D

5.

2.

fm ge ng in ee rin g.

co m A p ri l

XXX

XXX

XXX

XXX

221172

XXX

XXX

Legend

BH#1 Borehole Location

Borehole Location

Cross Section

R o s e b u d

H e a lt h

C a re F a c il it y A tr iu m I n fi ll

R o s e b u d

S o u th D a k o ta

B H

#1

B H

#3

0 10 20 30 40 50 60 70 80 90 100 110

P la s ti c it y I n d e x

P I)

Liquid Limit (LL)

PLASTICITY CHART

MH or OH

CH or OH

CL or

CL-ML

ML or OL

"A" Line

CLASSIFICATION OF SOILS FOR ENGINEERING PURPOSES

ASTM Designation: D 2487-90 and D 2488-90 (Unified Soil Classification System)

Soil Classification Criteria for Assigning Group Symbols and Group NamesA Group Symbol NameB

COARSE-GRAINED SOILS Gravels Clean Gravels Cu > 4 and 1 < Cc < 3E GW Well-Graded GravelF

More than 50% retained on More than 50% of coarse Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly Graded GravelF the No. 200 sieve fraction retained on No. 4 sieve Gravels with Fines Fines classify as ML or MH GM Silty GravelF,G,H

More than 12% finesC Fines classify as CL or CH GC Clayey GravelF,G,H

Sands Clean Sands Cu > 6 and 1 < Cc < 3E SW Well-Graded SandI

50% or more of coarse Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly Graded SandI fraction passes No. 4 sieve

Sands with Fines Fines classify as ML or MH SM Silty SandG,H,J

More than 12% finesD Fines classify as CL or CH SC Clayey SandG,H,I

FINE-GRAINED SOILS Silts and Clays inorganic PI>7and on or above "A" lineJ CL Lean ClayK,L,M

50% or more passes the Liquid limit less than 50 soils PI<4 or plots below "A" lineJ ML SiltK,L,M No. 200 sieve organic Liquid limit-oven dried

Organic ClayK,L,M,N

----------------------------<.75 OL

soils Liquid limit-not dried Organic SiltK,L,M,O

Silts and Clays inorganic PI plots on or above "A" line CH Fat ClayK,L,M

Liquid limit 50 or more soils PI plots below "A" line MH Elastic SiltK,L,M organic Liquid limit-oven dried

Organic ClayK,L,M,P

----------------------------<.75 OH

soils Liquid limit-not dried Organic SiltK,L,M,Q

HIGHLY ORGANIC SOILS Primarily organic matter, dark in color, and organic odor PT Peat

A. Based on the material passing the 3-in. (75-mm) sieve. G. If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM B. If field sample contained cobbles or boulders, or both, H. If fines are organic, add "with organic fines" to group name.

add "with cobbles and boulders, or both" to group name. I. If soil contains > 15% gravel, add "with gravel" to group name.

C. Gravels with 5% to 12% fines require dual symbols: J. If Atterberg limits plot in hatched area, soil is a CL-ML, silty clay.

GW-GM well-graded gravel with silt K. If soil contains 15% to 29% plus No. 200, add "with sand" or GW-GC well-graded gravel with clay "with gravel," whichever is predominant.

GP-GM poorly graded gravel with silt L. If soil contains > 30% plus No. 200, predominantly sand, add GP-GC poorly graded gravel with clay "sandy" to group name.

D. Sands with 5% to 12% fines require dual symbols: M. If soil contains > 30% plus No. 200, predominantly gravel, add SW-SM well-graded sand with silt "gravely" to group name.

SW-SC well-graded sand with clay N. PI > 4 and plots on or above "A" line.

SP-SM poorly graded sand with silt O. PI < 4 or plots below "A" line.

SP-SC poorly graded sand with clay P. PI plots on or above "A" line.

E. Cu = D

/D

Cc=(D

)2/D xD

Q. PI plots below "A" line.

F. If soil contains > 15% sand, add "with sand" to group name.

Equation of "A" - line: Horizontal at PI = 4 to LL = 25.5, then PI = 0.73(LL-20) (Chart is for general graphic presentation purposes only)

-- Figure 3

Appendix A

Geologic Logs

Fill B1A

B1B

B1C

B1D

B1E

Conc

VG

SM

Concrete Floor: 4 inches in thickness, plastic vapor barrier underneath.

Crushed Limestone Basecourse: 7 inches in thickness

Silty Sand: Pale brown, dry, non-plastic, medium dense. Some pieces of sandstone also present. Could be fill from previous excavation.

- Chunk of concrete.

- End of borehole at 5 feet. No groundwater encountered while sampling.

PROJECT: GEOLOGIC LOG BORING LOCATION: Basement

Rosebud Health Care Facility OF Employee Lounge

LOCATION: Rosebud, SD BOREHOLE 1 GROUND ELEVATION:

PROJECT #: 221172.00 DATUM:

DATE STARTED: 12/29/22 COMP.: 12/29/22 BORING DIAMETER: 3"

CONTRACTOR: FMG, Inc 605-342-4105 3700 Sturgis Road

Rapid City, SD 57702 fmgengineering.com

COLLAPSE DEPTH: n/a

DRILL METHOD: Hand Auger FILL DEPTH: n/a

SEE ATTACHED KEY FOR ABBREVIATIONS, NOTES & DESCRIPTIONS

ELEVATION /

DEPTH

W A

T E

R

GEOLOGY

GRAPHIC

Sample Info Type,#/Blows

USCS DESCRIPTION

NM

DD

(pcf)

LL

PI

Qu (psf) phi (deg)

Swell (ksf) sheet 1 of 1

B2A Conc

SP

Concrete Floor: 4 inches in thickness, with rebar.

Poorly Graded Sand: Pale brown, dry to moist, non-plastic, medium dense.

- End of borehole at 5 feet. No groundwater encountered while sampling.

PROJECT: GEOLOGIC LOG BORING LOCATION: Hole

Rosebud Health Care Facility OF Outside front entrance

LOCATION: Rosebud, SD BOREHOLE 2 GROUND ELEVATION:

PROJECT #: 221172.00 DATUM:

DATE STARTED: 12/29/22 COMP.: 12/29/22 BORING DIAMETER: 3"

CONTRACTOR: FMG, Inc 605-342-4105 3700 Sturgis Road

Rapid City, SD 57702 fmgengineering.com

COLLAPSE DEPTH: n/a

DRILL METHOD: Hand Auger FILL DEPTH: n/a

SEE ATTACHED KEY FOR ABBREVIATIONS, NOTES & DESCRIPTIONS

ELEVATION /

DEPTH

W A

T E

R

GEOLOGY

GRAPHIC

Sample Info Type,#/Blows

USCS DESCRIPTION

NM

DD

(pcf)

LL

PI

Qu (psf) phi (deg)

Swell

Fill B1A

B1B

B1C

B1D

B1E

Conc

VG

SM

Concrete Floor: 4 inches in thickness, plastic vapor barrier underneath.

Crushed Limestone Basecourse: 7 inches in thickness

Silty Sand: Pale brown, dry, non-plastic, medium dense. Some pieces of sandstone also present. Could be fill from previous excavation.

- Chunk of concrete.

- End of borehole at 5 feet. No groundwater encountered while sampling.

PROJECT: GEOLOGIC LOG BORING LOCATION: Main Level

Rosebud Health Care Facility OF In Front of Nurses Station

LOCATION: Rosebud, SD BOREHOLE 3 GROUND ELEVATION:

PROJECT #: 221172.00 DATUM:

DATE STARTED: 12/29/22 COMP.: 12/29/22 BORING DIAMETER: 3"

CONTRACTOR: FMG, Inc 605-342-4105 3700 Sturgis Road

Rapid City, SD 57702 fmgengineering.com

COLLAPSE DEPTH: n/a

DRILL METHOD: Hand Auger FILL DEPTH: n/a

SEE ATTACHED KEY FOR ABBREVIATIONS, NOTES & DESCRIPTIONS

ELEVATION /

DEPTH

W A

T E

R

GEOLOGY

GRAPHIC

Sample Info Type,#/Blows

USCS DESCRIPTION

NM

DD

(pcf)

LL

PI

Qu (psf) phi (deg)

Swell