ATTACHMENT 03 - 655-401 Geotechnical Report 10-27-2021.pdf

Report on Geotechnical Investigation

VA Saginaw 1500 Weiss Street

Saginaw, Michigan 48602

Latitude 43.446767˚ N Longitude 83.960833˚ W

Prepared for:

Alliance / 7GAE JV 600 E. Michigan Avenue, Suite B

Kalamazoo, Michigan 49007

G2 Project No. 190124 June 10, 2019

01 00 00 - A1

GENERAL REQUIREMENTS - APPENDIX A - GEOTECHNICAL REPORT

June 10, 2019

Sara Tripp, AIA, LEED AP Alliance / 7GAE JV 600 E. Michigan Avenue, Suite B Kalamazoo, Michigan 49007

Re: Report on Geotechnical Investigation VA Saginaw 1500 Weiss Street Saginaw, Michigan 48602 G2 Project No. 190124

Dear Ms. Tripp:

We have completed the geotechnical investigation for the improvements to the campus of the VA Saginaw hospital located at 1500 Weiss Street in Saginaw, Michigan. This report presents the results of our field investigation, our observations and analyses, and our recommendations for subgrade preparation, foundation design, and construction considerations as they relate to the geotechnical conditions at the site.

As always, we appreciate the opportunity to be of service to Alliance and look forward to discussing the recommendations presented herein. In the meantime, if you have any questions regarding this report or any other matter pertaining to the project, please call us.

Sincerely, G2 Consulting Group, LLC

Nathan M. Zaporski, E.I.T. Jennifer M. Casey, P.E.

Staff Engineer Project Manager

Noel J. Hargrave-Thomas, P.E.

Principal

NMZ/JMC/NJHT/ljv

Enclosures

APPENDIX A GEOTECHNICAL REPORT

G2 Project No. 190124

EXECUTIVE SUMMARY

We understand the project includes several proposed improvements to the existing VA hospital facility located in Saginaw, Michigan, inclusive of construction of a warehouse building, utilities building, backflow preventer building, outpatient mental health building, and outpatient physical therapy building on an approximately 10-acre site east of the existing campus. Underground stormwater detention, parking, access drives, and underground utilities will also be constructed. It should be noted that soil borings for the utilities and “FT” buildings (corresponding to borings B-03 through B-05) were not drilled due to soft ground and standing water on numerous attempts from early March through the end of May.

Approximately 2 to 14 inches of topsoil, 8 to 12 inches of sandy gravel, or 2 to 4 inches of bituminous concrete are present at the surface of the soil borings. Fill soils, generally consisting of soft to very stiff silty clay and very loose clayey sand, underlie the topsoil, gravel or bituminous concrete and extend to approximate depths of 1-1/2 to 6-1/2 feet. Buried topsoil is present at depths between 1 and 3-1/2 feet within soil borings B-01, B-06, B-07, B-08, and B-14. The underlying native soils are predominately cohesive and consist of primarily stiff to hard silty clay and sandy clay extending to the explored depths of 10 to 25 feet. Layers of native soft to medium cohesive soils are present between depths of 3-1/2 to 9 feet within soil borings B-09, B-11, and B-15 through B-17. A layer of native very loose sandy silt is present within soil boring B-12 from approximate depths of 3-1/2 to 5-1/2 feet. Groundwater was observed at depths of 1-1/4 to 7-2/3 feet during or upon completion of drilling.

We recommend the proposed buildings be supported on conventional spread and strip footing foundations extending through any existing fill soils, buried topsoil, or loose soils, and bearing in the underlying native silty clay. We recommend foundations for the proposed warehouse bear within the native hard silty clay and be designed for a net allowable bearing capacity of 5,000 psf. We recommend foundations for the proposed outpatient mental health building bear within the native stiff to very stiff silty clay and be designed for a net allowable soil bearing capacity of 2,500 psf. Based on the subsurface conditions at the boring locations, foundations may need to extend to depths of up to 6-1/2 feet to extend through the fill soils and buried topsoil. We recommend foundations for the proposed outpatient physical therapy building bear within the native medium to very stiff silty clay. Foundations bearing on these soils can be designed for a net allowable soil bearing capacity of 2,000 psf. Based on the subsurface conditions at the boring locations, foundations may need to extend to depths of up to 5-1/2 feet to extend through the fill soils.

No information was available regarding the proposed backflow preventer building at the time of this report. However, we anticipate that this structure will be below grade. We recommend the proposed backflow preventer be supported on conventional spread and strip footings, extending through the existing fill soils and medium silty clay and bearing within the underlying hard silty clay. For foundation depths between 3-1/2 and 11 feet, foundations can be designed for a net allowable soil bearing capacity of 6,000 psf. If the depth of foundations exceeds 11 feet, then a reduced net allowable soil bearing capacity of 2,000 psf should be used.

Exterior footings should bear at a minimum depth of 3-1/2 feet below finished grade for protection against frost heave. Interior foundations can bear at shallower depths provided suitable bearing soils are present and foundations are protected from frost during construction. Based on fill depths foundations will bear at depths up to 6-1/2 feet below existing grade. We recommend a G2 engineer be on site during construction to observe all foundation construction activities. Caving and sloughing of the existing fill soils and buried topsoil may occur during excavation operations for the proposed foundations. The contractor should be prepared to over excavate and form the footings within existing fill soils, as necessary.

Do not consider this summary separate from the entire text of this report, with all the conclusions and qualifications mentioned herein. Details of our analysis and recommendations are discussed in the following sections and in the Appendix of this report.

APPENDIX A - GEOTECHNICAL REPORT

PROJECT DESCRIPTION

We understand the project includes several proposed improvements to the existing VA hospital facility located in Saginaw, Michigan, inclusive of construction of a warehouse building, utilities building, backflow preventer building, outpatient mental health building and outpatient physical therapy building on an approximately 10-acre site east of the existing campus. Underground stormwater detention, parking, access drives and underground utilities will also be constructed. It should be noted that soil borings for the utilities and “FT” buildings (corresponding to borings B-03 through B-05) were not drilled due to soft ground and standing water on numerous attempts from early March through the end of May.

Structural loading conditions for proposed buildings were not available at the time of this report.

However, we understand that the warehouse building will be a single-story masonry structure. We anticipate the loading conditions for the buildings will be relatively light, with anticipated wall loads ranging between 3 and 8 kips per lineal foot. Final grades were also unavailable at the time of this report. However, we anticipate that final grades will be near existing grades. G2 must be notified when actual loading conditions and final grades have been determined so that we may review the recommendations presented herein.

SCOPE OF SERVICES

Field operations, laboratory testing, and engineering report preparation were performed under the direction and supervision of a licensed professional engineer. Our services were performed according to generally accepted standards and procedures in the practice of geotechnical engineering in this area.

Our scope of services for this project is as follows:

1. We drilled a total of thirteen (13) soil borings, with 2 extending to a depth of 20 feet within the footprint of the proposed warehouse, 2 extending to a depth of 20 feet within the footprint of the proposed outpatient mental health building, 2 extending to a depth of 20 feet within the footprint of the proposed outpatient physical therapy building, 2 extending to 15 feet, 1 extending to 20 feet and 1 extending to 25 feet within the proposed stormwater detention area, and 3 extending to 10 feet within the areas of the proposed new pavements and access drive.

2. We performed laboratory testing, including visual engineering classification, natural moisture content, organic matter content, dry density, and unconfined compressive strength determinations on representative samples obtained from the soil borings.

3. We prepared this engineering report. Our report includes recommendations regarding foundation types suitable for the soil conditions encountered, allowable bearing capacities of the anticipated bearing soils, estimated settlement, floor slab and pavement design recommendations, and construction considerations related to foundation construction and site development.

FIELD OPERATIONS

Alliance / 7GAE JV, in conjunction with G2 Consulting Group, LLC (G2), selected the number, depth, and location of the soil borings. The soil borings were located in the field by a G2 staff engineer by measuring from existing site features, landmarks, and building corner survey stakes using conventional taping methods and hand-held GPS technology. The approximate soil boring locations are shown on the Soil Boring Location Plan, Plate No. 1. Ground surface elevations were not available at the time of this report. We recommend that the boring locations be surveyed so that soil stratigraphy may be properly correlated to elevation throughout the site.

The soil borings were drilled using a truck-mounted rotary drilling rig and/or an ATV-mounted rotary drilling rig. Continuous-flight, 3-1/4 inch inside diameter, hollow-stem augers were used to advance the boreholes. Soil samples were generally obtained at intervals of 2-1/2 feet within the upper 10 feet and at intervals of 5 feet below that depth. These samples were obtained by the Standard Penetration Test Method (ASTM D 1586), which involves driving a 2-inch diameter split-spoon sampler into the soil with a 140-pound weight falling 30 inches. The sampler is generally driven three successive 6-inch increments, with the number of blows for each increment recorded. The number of blows required to advance the sampler the last 12 inches is termed the Standard Penetration Resistance (N). Blow counts for each six-inch increment and resulting N-values are presented on the individual soil boring logs.

The soil samples were placed in sealed containers in the field and brought to our laboratory for testing and classification. During field operations, drilling representatives maintained soil boring logs of the subsurface conditions, including changes in stratigraphy and observed groundwater levels. The final boring logs are based on the field logs supplemented by laboratory soil classification and test results.

The soil borings were backfilled with auger cuttings upon completion of drilling operations.

LABORATORY TESTING

Representative soil samples were subjected to laboratory testing to determine soil parameters pertinent to foundation design and site preparation. An experienced geotechnical engineer classified the samples in general conformance with the Unified Soil Classification System. Laboratory testing on representative samples included:

ASTM D 2216 – Moisture Content & Dry Density ASTM D 2166 – Unconfined Compressive Strength ASTM D 2974 – Moisture, Ash Organic Matter Content (LOI)

The unconfined compressive strengths were determined by ASTM Test Method D 2166 and using a spring-loaded hand penetrometer. Per ASTM Test Method D 2166, the unconfined compressive strength of cohesive soils is determined by axially loading a small cylindrical soil sample under a slow rate of strain. The unconfined compressive strength is defined as the maximum stress applied to the soil sample before shear failure. If shear failure does not occur prior to a total strain of 15 percent, the unconfined compressive strength is defined as the stress at a total strain of 15 percent. The hand penetrometer estimates the unconfined compressive strength to a maximum of 4-1/2 tons per square foot (tsf), which is converted to psf, by measuring the resistance of the soil sample to the penetration of a calibrated spring-loaded cylinder.

The results of the moisture content, organic matter content, dry density, and unconfined compressive strength laboratory tests are indicated on the boring logs at the depths the samples were obtained. The unconfined compressive strength determined using ASTM D2166 is also presented graphically on the Unconfined Compressive Strength Tests, Figure Nos. 18 and 19. We will hold the soil samples for 60 days from the date of this report, after which time they will be discarded. If you would like to retain the samples beyond that date, please let us know.

SITE CONDITIONS

The improvements to the existing VA facility are located on a partially vacant 10-acre lot on the east side of the VA campus. The southern portion of the parcel is used for parking and is covered by heavily-distressed bituminous concrete pavement. An outbuilding is located within the central portion of the parcel. The northern portion of the parcel is heavily wooded. Standing water and soft ground conditions between March and May of 2019 made some of the borings inaccessible. These will need to be drilled at a later date. An abandoned rail spur is present in the northeast corner of the parcel. The parcel is bounded to the north by railroad tracks, to the west by the existing VA facilities, to the east by commercial property and to the south by Weiss Street.

SOIL CONDITIONS

Warehouse (B-01 and B-02)

Approximately 2 to 14 inches of topsoil are present at the surface of soil borings B-01 and B-02. Fill soils, consisting of clayey sand and silty sand underlie the topsoil and extend to approximate depths of 2 to 3-1/2 feet. A layer of buried topsoil is present within soil boring B-01 between approximate depths of 1-1/2 and 2 feet. Native silty sand underlies the fill soils within soil boring B-02 and extends to an approximate depth of 3-1/2 feet. Native silty clay underlies the fill and native sand and extends to the explored depth of 20 feet within both borings.

The granular fill soils are very loose to loose with Standard Penetration Test (SPT) N-values ranging 4 and 5 blows per foot and an organic matter content of 4.6 percent. The native silty sand within soil boring B-02 is loose with an SPT N-value of 5. The native silty clay soils are very stiff to hard in consistency to approximate depths of 18 and 13-1/2 feet within soil borings B-01 and B-02, respectively, with natural moisture contents ranging between 9 and 16 percent, dry densities ranging between 121 and 123 pounds per cubic foot (pcf) and unconfined compressive strengths ranging between 6,140 and 9,000 pounds per square foot (psf). The underlying native cohesive soils are generally medium to very stiff in consistency, with natural moisture contents of approximately 15 percent, a dry density of 118 pcf and unconfined compressive strengths ranging between 1,000 and 5,000 psf.

Outpatient Mental Health (B-06 and B-07)

Approximately 8 to 12 inches of topsoil are present at the surface of soil borings B-06 and B-07.

Cohesive fill soils consisting of silty clay and sandy clay underlie the topsoil and extend to approximate depths of 6 to 6-1/2 feet. Buried topsoil layers are present in both soil borings between approximate depths of 2 and 3-1/2 feet within soil boring B-06 and 3-1/2 to 4 feet within soil boring B-07. Native silty clay underlies the fill and buried topsoil and extends to the explored depth of 20 feet within both soil borings.

The cohesive fill soils are generally medium to stiff in consistency, with moisture contents ranging between 18 and 23 percent, an organic matter content of approximately 4 percent, and unconfined compressive strengths ranging between 1,000 and 4,000 psf. The native silty clay is generally stiff to very stiff in consistency with natural moisture contents ranging between 13 and 17 percent, dry densities ranging between 109 and 124 pcf, and unconfined compressive strengths ranging between 2,000 and 4,880 psf. However, a layer of hard silty clay is present between approximate depths of 8 and 13 feet within soil boring B-06 with a natural moisture content of 8 percent and an unconfined compressive strength of 9,000 psf.

Outpatient Physical Therapy (B-08 and B-09)

Approximately 10 inches of topsoil are present at the surface of soil boring B-09. Cohesive fill soils are present at the surface of soil boring B-08 and underlie the topsoil within soil boring B-09, extending to approximate depths of 3-1/2 feet within soil boring B-08 and 5-1/2 feet within soil boring B-09. A layer of buried topsoil is present between approximate depths of 2 and 3-1/2 feet within soil boring B-08.

Native silty clay underlies the fill soils and extends to the explored depth of 20 feet within both borings.

The cohesive fill soils are generally very stiff in consistency, with moisture contents ranging between 12 and 14 percent, an organic matter content of approximately 4 percent, and unconfined compressive strengths ranging between 6,000 and 6,500 psf. However, the cohesive fill soil between approximate depths of 3 and 5-1/2 feet within soil boring B-09 is soft in consistency, with a moisture content of 24 percent and an unconfined compressive strength of 500 psf. The native silty clay is generally stiff to very stiff in consistency with natural moisture contents ranging between 12 and 15 percent, dry densities ranging between 122 and 126 pcf, and unconfined compressive strengths ranging between

3,000 and 6,710 psf. A layer of hard silty clay is present within soil boring B-08 between approximate depths of 8 and 13 feet with a natural moisture content of 12 percent and an unconfined compressive strength of 9,000 psf. A layer of medium silty clay is present between approximate depths of 5-1/2 feet and 9 feet within soil boring B-09 with a natural moisture content of 20 percent, a dry density of 115 pcf, and an unconfined compressive strength of 1,530 psf.

Backflow Preventer Building (B-10)

Approximately 3 inches of bituminous concrete are present at the surface of soil boring B-10, underlain by approximately 5 inches of sandy gravel aggregate base and 5 inches of silty sand fill. Native silty clay underlies the fill soils and extends to the explored depth of 20 feet.

The native silty clay between approximate depths of 1 and 3-1/2 feet is medium in consistency with a natural moisture content of 21 percent, an organic matter content of 3 percent and an unconfined compressive strength of 1,500 psf. Below 3-1/2 feet, the silty clay is generally very stiff to hard to an approximate depth of 18 feet with natural moisture contents ranging between 12 and 15 percent and unconfined compressive strengths ranging between 6,000 and 9,000 psf. The underlying silty clay is medium to stiff in consistency with a natural moisture content of 15 percent and an unconfined compressive strength of 2,000 psf.

Stormwater Detention (B-11 through B-14)

Approximately 2 to 4 inches of bituminous concrete is present at the surface of soil borings B-11 through B-13, underlain by approximately 6 to 8 inches of sandy gravel aggregate base and approximately 6 to 8 inches of silty sand fill. Approximately 8 inches of sandy gravel aggregate base material is present at the surface of soil boring B-14, underlain by approximately 8 inches of buried topsoil. Silty clay fill with organic matter underlie the pavement section within soil borings B-11 through B-13 and extends to approximate depths of 3 to 3-1/2 feet. Native silty clay generally underlies the fill soils within borings B-11 through B-13, and topsoil within B-14 and extends to the explored depths.

However, a layer of native sandy silt is present between approximate depths of 3-1/2 and 5-1/2 feet within soil boring B-12.

The silty clay fill is generally soft to medium in consistency with moisture contents ranging between 20 and 24 percent, organic matter contents ranging between 4 and 8 percent, and unconfined compressive strengths of approximately 500 psf. The native silty clay is generally very stiff to hard in consistency with natural moisture contents ranging between 11 and 17 percent and unconfined compressive strengths ranging between 5,000 and 9,000 psf. A layer of medium native silty clay is present between approximate depths of 3 and 5-1/2 feet within soil borings B-11 and B-13, with natural moisture contents ranging between 16 and 24 percent and unconfined compressive strengths ranging between 1,000 and 2,000 psf. Stiff to very stiff silty clay is present within soil borings B-13 and B-14 below depths of 18 feet and 13 feet, respectively, with natural moisture contents ranging between 12 and 17 percent and an unconfined compressive strength of 2,500 psf.

Access Drive and North Parking Lot Pavements (B-15 through B-17)

Approximately 12 inches of topsoil is present at the surface of soil boring B-15. Approximately 8 to 12 inches of sandy gravel fill is present at the surface of soil borings B-16 and B-17. Cohesive fill soils consisting of sandy clay and silty clay underlie the topsoil and sandy gravel fill and extend to approximate depths of 3 to 4-1/2 feet within soil borings B-15 through B-17. Native silty clay underlies the fill soils and extends to the explored depth of 10 feet within soil borings B-15 through B-17.

The cohesive fill soils are generally soft medium in consistency with moisture contents ranging between 15 and 26 percent, an organic matter content of approximately 6 percent, and unconfined compressive strengths ranging between 1,000 and 1,500 psf. However, the cohesive fill soils within soil boring B-17 are very stiff in consistency with a moisture content of 13 percent and an unconfined compressive strength of 5,000 psf. The upper native silty clay extending to depths of 6 to 8 feet is medium to soft in consistency, with natural moisture contents ranging between 17 and 22 percent and unconfined compressive strengths ranging between 1,000 and 1,500 psf. The deeper native silty clay is generally very stiff to hard in consistency with natural moisture contents ranging between 12 and 14 percent, and unconfined compressive strengths ranging between 6,500 and 9,000 psf.

General

The stratification depths shown on the soil boring logs represent the soil conditions at the boring locations. Variations may occur away from the boring locations. Additionally, the stratigraphic lines represent the approximate boundary between soil types. The transition may be more gradual than what is shown. We have prepared the boring logs on the basis of the field logs of soils encountered supplemented by laboratory classification and testing.

The Soil Boring Location Plan, Plate No. 1, and Soil Boring Logs, Figure Nos. 1 through 17, are presented in the Appendix. The soil profiles described above are generalized descriptions of the conditions encountered at the boring locations. The unconfined compressive strength determined in accordance with ASTM D2166 is also presented graphically on the Unconfined Compressive Strength Tests, Figure Nos. 18 and 19. General Notes Terminology defining the nomenclature used on the soil boring logs and elsewhere in this report is presented on Figure No. 20.

GROUNDWATER CONDITIONS

Groundwater observations were made during and upon completion of drilling. Groundwater was encountered during drilling at depths ranging from 1-1/4 to 4-1/2 feet within soil borings B-02, B-09, B-12, and B-16. Upon completion, the water level was measured at depths ranging from 3-1/2 to 7-2/3 feet within soil borings B-02 and B-12, respectively. No measurable groundwater was observed within borings B-02, B-09, and B-16 upon completion of drilling. No measurable groundwater was observed within soil borings B-01, B-06 through B-08, B-10, B-11, B-13 through B-15, and B-17 during or upon completion of drilling.

Fluctuations in perched and long-term groundwater levels should be anticipated due to seasonal variations and following periods of prolonged precipitation. It should also be noted that groundwater observations made during drilling operations in predominantly cohesive soils are not necessarily indicative of the static groundwater level. This is due to the low permeability of such soils and the tendency of drilling operations to seal off the natural paths of groundwater flow.

SITE PREPARATION

We anticipate earthwork operations will consist of clearing all vegetation, topsoil, and pavements from the proposed building and pavement areas, demolishing the existing building and associated foundations, removing and relocating existing utilities, backfilling resulting foundation and utility excavations with engineered fill, proof rolling the exposed subgrade, preparing the subgrade for support of floor slabs and pavements, and excavating and backfilling for the stormwater detention system, new foundations, and new utilities. We recommend all earthwork operations be performed under adequate specifications and properly monitored in the field by qualified geotechnical engineers and technicians.

At the start of earthwork operations, any topsoil, vegetation, and pavement within the proposed building and pavement areas should be completely removed. We recommend the existing pavement in the southern portion of the site remain in place during building construction and used as a laydown area.

The existing pavement should be removed and replaced once substantial completion of the building construction is performed to minimize exposing the existing cohesive soils with organic content and relatively high moisture contents to the environment. This will minimize the potential for pavement subgrade undercuts. Following removal of the existing pavements, utilities and vegetation, we recommend the exposed subgrade be proof compacted if granular, using a large vibratory roller making a minimum of 10 passes in two perpendicular directions. The cohesive fill subgrade soils should be proof-rolled using a heavily-loaded, single axle, dump truck. Any unstable or unsuitable areas noted during proof-rolling/compacting operations should be undercut and replaced with engineered fill.

Based on the presence of organic matter in the upper cohesive fill and buried topsoil layers present throughout the site, we anticipate undercuts will be required. All undercuts backfilled with granular engineered fill should have drain tiles connected to the stormwater management system to promote drainage and prevent water accumulation within the undercut excavations.

Any engineered fill placed within the site should consist of an approved, environmentally clean material.

Engineered fill should be free of organic matter, frozen soil, clods, or other harmful substances. The fill should be placed in uniform horizontal layers, not more than 9 inches in loose thickness. The engineered fill should be compacted to achieve a density of at least 95 percent of the maximum dry density, as determined by the Modified Proctor compaction test (ASTM D 1557). Any granular fill used within the site should be compacted within 2 percent of optimum moisture content. Frozen material should not be used as fill, nor should fill be placed on a frozen subgrade. The existing fill is not suitable for reuse as engineered fill below structures, if required, due to the presence of organic matter.

We recommend using granular engineered fill within confined areas, such as utility trenches and adjacent to foundations, catch basins and the proposed stormwater detention system. Granular engineered fill is generally more easily compacted than cohesive soils within these confined areas.

Additionally, the proper placement and compaction of backfill within these areas is imperative to provide adequate support for overlying floor slabs and pavements.

STORMWATER DETENTION SYSTEM RECOMMENDATIONS

Soil conditions within the proposed stormwater detention area consist predominantly of stiff to hard silty clay extending to the explored depths ranging between 15 and 25 feet. The silty clay has an estimated hydraulic conductivity of less than 1 x 10-7 centimeters per second, which is considered to be practically impermeable. As such, it should be anticipated that collected water will not drain and will need to be discharged by a storm sewer outlet.

FLOOR SLAB RECOMMENDATIONS

Warehouse, Outpatient Mental Health and Outpatient Physical Therapy

The existing fill soils and buried topsoil within the footprints of the proposed warehouse, outpatient mental health, and outpatient physical therapy buildings are marginally suitable for the support of floor slabs. Provided some floor slab settlement can be tolerated, the existing fill soils that pass the proof-rolled/compacted evaluation as described in the Site Preparation section of this report can be used to support the proposed floor slabs. We recommend a subgrade modulus (k) of up to 100 pounds per cubic inch (pci) may be used in the design of floor slab supported on the existing fill.

If the potential for floor slab settlement cannot be tolerated, the existing fill and buried topsoil must be completely removed and replaced with engineered fill for support of the building floor slab. We recommend the existing fill soils be removed beneath the entire building area and a minimum of 10 feet beyond the building footprint in all directions. A subgrade modulus (k) of up to 150 pci may be used in the design of floor slabs supported on the engineered fill overlying native soil.

General

We recommend at least 4 inches of clean coarse sand or pea gravel be placed between the subgrade and the bottom of the floor slab for use as a capillary break to reduce moisture transmission through the concrete floors and to reduce the potential for concrete curling. If moisture sensitive floor coverings are planned or if greater protection against vapor transmission is desired, a vapor barrier consisting of 10 mil plastic sheeting, or equivalent, may be placed on the sand layer beneath floor slabs. The floor slab should be isolated from the foundation system to allow for independent movement.

FOUNDATION RECOMMENDATIONS

Warehouse (B-01 and B-02)

We recommend the proposed warehouse building be supported on conventional spread and strip footing foundations extending through any existing fill or loose granular soils and bearing within the underlying native very stiff to hard silty clay. Foundations bearing on these soils can be designed for a net allowable soil bearing capacity of 5,000 psf. Based on soil boring B-01 and B-02, all foundations will extend to an approximate depth of 3-1/2 feet below existing grade to bear on native soils. If the existing fill soils are removed and replaced with engineered fill, interior foundations can bear at a shallower depth within the engineered fill placed over the native soils. Foundation bearing within the engineered fill can be designed based on an allowable bearing pressure of 3,000 psf.

Outpatient Mental Health (B-06 and B-07)

We recommend the proposed outpatient mental health building be supported on conventional spread and strip footing foundations extending through any existing fill or buried topsoil and bearing within the underlying native stiff to very stiff silty clay. Foundations bearing on these soils can be designed for a net allowable soil bearing capacity of 2,500 psf. Based on the subsurface conditions at the boring locations, foundations will extend to depths of up to 6-1/2 feet to extend through the fill soils and buried topsoil to bear on native soil.

Alternately, the existing fill may be removed under the zone of influence of proposed foundations and replaced with engineered fill soils. Foundations bearing on engineered fill may bear at conventional depths and may be designed based on a net allowable bearing pressure of 2,500 psf. The foundation zone of influence is defined as illustrated in Figure 1 below.

Undisturbed Native Soil

Foundation

Distance x/2

Engineered Fill

D is ta n ce x

Distance x/2 Existing Fill Soil

Existing Fill Soil

Engineered Fill

Engineered Fill Engineered Fill

Figure 1

If the existing fill soils and buried topsoil are removed and replaced with engineered fill for support of the floor slabs, foundations can bear within the engineered fill placed over native soils at conventional bearing depths. Foundations bearing within the engineered fill may be designed based on an allowable bearing pressure of 2,500 psf.

Outpatient Physical Therapy (B-08 and B-09)

We recommend the proposed outpatient physical therapy building be supported on conventional spread and strip footing foundations extending through any existing fill or buried topsoil soils and bearing within the underlying native medium to very stiff silty clay. Foundations bearing on these soils can be designed for a net allowable soil bearing capacity of 2,000 psf. Based on the subsurface conditions at the boring locations, foundations may need to extend to depths of up to 5-1/2 feet to extend through the fill soils.

Alternately, the existing fill may be removed under zone of influence of proposed foundations and replaced with engineered fill soils. Foundations bearing on engineered fill may bear at conventional depths and may be designed based on an allowable bearing pressure of 2,500 psf. The foundation zone of influence is defined as illustrated in Figure 1 above.

If the existing fill soils and buried topsoil are removed and replaced with engineered fill for support of the floor slabs, foundations can bear within the engineered fill placed over native soils at conventional bearing depths. Foundations bearing within the engineered fill may be designed based on an allowable bearing pressure of 2,500 psf.

Backflow Preventer Building

No information as was available regarding the proposed backflow preventer building at the time of this report. We anticipate that this structure will be below grade. We recommend the proposed backflow preventer be supported on conventional spread and strip footings, extending through the existing fill soils and medium silty clay and bearing within the underlying hard silty clay. For foundation depths between 3-1/2 and 11 feet, foundations can be designed for a net allowable soil bearing capacity of 6,000 psf. If the depth of foundations exceeds 11 feet, then a reduced net allowable soil bearing capacity of 2,000 psf should be used.

General

Exterior footings should bear at a minimum depth of 3-1/2 feet below finished grade for protection against frost heave. Interior foundations can bear at shallower depths provided suitable bearing soils are present and foundations are protected from frost during construction. We recommend a G2 engineer be on site during construction to observe the excavations, measure the bearing depths, and verify the adequacy of the bearing soils.

Continuous wall or strip footings should be at least 16 inches in width and isolated spread footings should be at least 30 inches in their least dimension. To achieve a change in the level of the strip footings, the footings should be gradually stepped at a grade no steeper than two units horizontal to one unit vertical. We recommend all strip footings be suitably reinforced to minimize the effects of differential settlements associated with local variations in subsoil conditions. Adjacent spread footings at different levels should be designed and constructed so the least lateral distance between them is equivalent to or more than the difference in their bearing levels.

Caving and sloughing of the existing fill soils and buried topsoil may occur during excavation operations for the proposed foundations. The contractor should be prepared to over excavate and form the footings that extend through the existing fill soils and buried topsoil or engineered fill used to replace the existing fill and topsoil, as necessary. The sides of the spread and/or strip footing foundations should be constructed straight and vertical to reduce the risk of frozen soil adhering to the concrete and raising the foundations.

If the recommendations outlined in this report are adhered to, total and differential settlements for the completed structure should be within 1 inch and 1/2 inch, respectively. We expect settlements of these magnitudes are within tolerable limits for the type of structure proposed. We recommend all foundations be suitably reinforced to minimize the effects of differential settlements associated with local variations in subsoil conditions.

BELOW-GRADE WALL RECOMMENDATIONS

We anticipate that the proposed backflow preventer building will incorporate below-grade walls. No information with regard to the design of the proposed backflow preventer building was available at the time of this report. Any below-grade walls should be designed to resist lateral soil loads modeled as an equivalent fluid pressure. Walls considered to be fixed at the top should be designed on the basis of at-rest earth lateral earth pressures corresponding to an equivalent fluid pressure of 55 pounds per square foot per foot of depth for drained soil conditions and 85 pounds per square foot per foot of depth for undrained soil conditions.

We recommend below grade walls be backfilled with free-draining granular soils. Lateral earth pressures are significantly influenced by the type and intensity of backfill compaction. We recommend only relatively small compaction equipment be used to compact backfill placed against below grade walls.

We recommend a perimeter foundation drain system be incorporated at the foundation level to prevent the development of hydrostatic pressures on below-grade floors and walls. The perforated or slotted drain pipe should be protected with coarse aggregates. The drain pipe and aggregate should be wrapped with a non-woven filter fabric to prevent the migration of surrounding soil fines into the aggregate and drain pipe. The drainage system should outlet water to a sump/pump system or storm drain.

In order to make below grade walls more resistant to passage of water vapor from outside and to increase their resistance to capillary penetration of water, the exterior below grade walls should be treated with an impervious membrane, such as MIRA-Dry or equivalent. The continuity and resulting effectiveness in resisting moisture penetration depends on the smoothness and regularity of the concrete surface and workmanship in applying the membrane materials to the dry concrete surface.

PAVEMENT RECOMMENDATIONS

We understand the project includes construction of an access drive along the eastern half of the property, as well as new pavements for parking throughout the site. Proposed grades were not available at the time of this report. We anticipate subgrade soils will consist of the existing fill soils. The subgrade should be properly prepared as outlined above in the Site Preparation section of this report.

For purposes of this design and in consideration of the deeper fill deposits with high organic content and buried topsoil present throughout the site, we have assumed a conservative effective roadbed soil resilient modulus of 4,000 pounds per square inch (psi). We have assumed that traffic will consist mainly of passenger vehicles, as well as occasional sanitation, delivery and emergency vehicles.

We performed pavement design analyses in accordance with the “AASHTO Guide for Design of Pavement Structures”. We anticipate the proposed traffic will consist of car and occasional garbage or delivery vehicles. Based on the anticipated traffic, we have designed a standard-duty pavement section to be used for the pavement areas. The standard-duty pavement section is based on an estimated 75,000 ESALS over a 20-year design life. For evaluation purposes, we estimated a serviceability loss of 2.0, a standard deviation of 0.45, and a reliability factor of 0.85. If any actual traffic volume information becomes available, G2 should be notified so we can re-evaluate our recommendations.

Based on the results of our analyses, we recommend a minimum standard-duty pavement design section consisting of 2 inches of MDOT 5E1 bituminous concrete wearing course and 2 inches of MDOT 3C bituminous concrete leveling course supported on a minimum of 10 inches of MDOT 21AA dense graded aggregate base material. All pavement materials are specified within the 2012 Standard Specifications for Construction from the Michigan Department of Transportation. The bituminous pavement materials are described in Section 501 and can be assigned a structural coefficient number of 0.42. Any new imported aggregate base course material can be assigned a structural coefficient number of 0.14.

Standard Duty Flexible Pavement Section

Material Thickness Structural Coefficient

MDOT 5E1 Bituminous Wearing Course 2 inches 0.42

MDOT 3C Bituminous Leveling Course 2 inches 0.42

MDOT 21AA (dense-graded aggregate) 10 inches 0.14

Total SN = 3.08

The pavement and subgrade should be properly sloped to promote effective surface and subsurface drainage and prevent water ponding. Edge drains should be constructed along the curb and gutters and should be connected to a nearby storm sewer. Regular timely maintenance should be performed on the bituminous pavement to reduce the potential deterioration associated with moisture infiltration through surface cracks. The owner should be prepared to seal the cracks with a hot-applied elastic crack filler as soon as possible after cracking develops and as often as necessary to block the passage of water to the subgrade soils.

CONSTRUCTION CONSIDERATIONS

No significant groundwater accumulations are anticipated in foundation excavations of the depths anticipated for proposed foundations. In general, we expect accumulations of surface run-off water and groundwater seepage at the base of the excavations should be controllable with pumping from properly constructed sumps. As mentioned above, several borings were made inaccessible due to standing water and soft ground. Further instability should be expected following periods of rain. We recommend work be performed in the drier summer months to prevent instability in the largely cohesive subgrade soils.

Caving and sloughing of the existing upper fill soils and buried topsoil may occur during excavation operations for the proposed foundations. The contractor should be prepared to over excavate and form the footings within existing fill soils, as necessary. The sides of the spread and/or strip footing foundations should be constructed straight and vertical to reduce the risk of frozen soil adhering to the concrete and raising the foundations.

All excavations should be safely sheeted, shored, sloped, or braced in accordance with MI-OSHA requirements. If material is stored or equipment is operated near an excavation, stronger shoring must be used to resist the extra pressure due to the superimposed loads.

Care should be exercised when excavating near any existing structures, utilities, or pavements to avoid undermining. Under no circumstances should excavations extend below the level of existing footings, utilities, or pavements unless underpinning is planned.

GENERAL COMMENTS

We have formulated the evaluations and recommendations presented in this report relative to site preparation and foundations on the basis of data provided to us relating to the location, type, and grade for the proposed site. Any significant change in this data should be brought to our attention for review and evaluation with respect to the prevailing subsurface conditions. Furthermore, if changes occur in the design, location, or concept of the project, the conclusions and recommendations contained in this report are not valid unless G2 Consulting Group, LLC reviews the changes. G2 Consulting Group, LLC will then confirm the recommendations presented herein or make changes in writing.

The scope of the present investigation was limited to evaluation of subsurface conditions for the support of proposed buildings and other related aspects of the development. No chemical, environmental or hydrogeological testing or analyses were included in the scope of this investigation.

We base the analyses and recommendations submitted in this report upon the data from the soil borings performed at the approximate locations shown on the Soil Boring Location Plan, Plate No. 1. This report does not reflect variations that may occur away from the actual boring locations. The nature and extent of any such variations may not become clear until the time of construction. If significant variations then become evident, it may be necessary for us to re-evaluate our report recommendations.

Accordingly, we recommend G2 Consulting Group, LLC observe all geotechnical related work, including foundation construction, subgrade preparation, and engineered fill placement. G2 Consulting Group, LLC will perform the appropriate testing to confirm the geotechnical conditions given in the report are found during construction.

APPENDIX

Soil Boring Location Plan Plate No. 1

Soil Boring Logs Figure Nos. 1 through 17

Unconfined Compressive Strength Test Figure Nos. 18 and 19

General Notes Terminology Figure No. 20

Scale: NTS

Date: 6/5/19

Drawn by: NMZ

Project No. 190124

Plate No. 1

VA Saginaw 1500 Weiss Street

Saginaw, Michigan 48602Soil borings drilled by BRAX Drilling, Inc. on March 23 and May 28, 2019

Figure No. 20

GENERAL NOTES TERMINOLOGY

Unless otherwise noted, all terms herein refer to the Standard Definitions presented in ASTM 653.

PARTICLE SIZE

Boulders - greater than 12 inches Cobbles - 3 inches to 12 inches Gravel - Coarse - 3/4 inches to 3 inches

- Fine - No. 4 to 3/4 inches Sand - Coarse - No. 10 to No. 4

- Medium - No. 40 to No. 10

- Fine - No. 200 to No. 40

Silt - 0.005mm to 0.074mm Clay - Less than 0.005mm

CLASSIFICATION

The major soil constituent is the principal noun, i.e. clay, silt, sand, gravel. The second major soil constituent and other minor constituents are reported as follows:

Second Major Constituent (percent by weight)

Minor Constituent (percent by weight)

Trace - 1 to 12% Trace - 1 to 12% Adjective - 12 to 35% Little - 12 to 23% And - over 35% Some - 23 to 33%

COHESIVE SOILS

If clay content is sufficient so that clay dominates soil properties, clay becomes the principal noun with the other major soil constituent as modifier, i.e. sandy clay. Other minor soil constituents may be included in accordance with the classification breakdown for cohesionless soils, i.e. silty clay, trace sand, little gravel.

Consistency Unconfined Compressive

Strength (psf) Approximate Range of (N) Very Soft Below 500 0 - 2

Soft 500 - 1,000 3 - 4 Medium 1,000 - 2,000 5 - 8

Stiff 2,000 - 4,000 9 - 15 Very Stiff 4,000 - 8,000 16 - 30

Hard 8,000 - 16,000 31 - 50 Very Hard Over 16,000 Over 50

Consistency of cohesive soils is based upon an evaluation of the observed resistance to deformation under load and not upon the Standard Penetration Resistance (N).

COHESIONLESS SOILS

Density Classification Relative Density % Approximate Range of (N)

Very Loose 0 - 15 0 - 4 Loose 16 - 35 5 - 10

Medium Compact 36 - 65 11 - 30 Compact 66 - 85 31 - 50

Very Compact 86 - 100 Over 50

Relative Density of cohesionless soils is based upon the evaluation of the Standard Penetration Resistance (N), modified as required for depth effects, sampling effects, etc.

SAMPLE DESIGNATIONS

AS - Auger Sample – Cuttings directly from auger flight BS - Bottle or Bag Samples S - Split Spoon Sample - ASTM D 1586 LS - Liner Sample with liner insert 3 inches in length ST - Shelby Tube sample - 3 inch diameter unless otherwise noted PS - Piston Sample - 3 inch diameter unless otherwise noted RC - Rock Core - NX core unless otherwise noted

STANDARD PENETRATION TEST (ASTM D 1586) - A 2.0 inch outside-diameter, 1-3/8 inch inside-diameter split barrel sampler is driven into undisturbed soil by means of a 140-pound weight falling freely through a vertical distance of 30 inches. The sampler is normally driven three successive 6-inch increments. The total number of blows required for the final 12 inches of penetration is the Standard Penetration Resistance (N).