589A4-20-158 GeoTech Report.pdf

1000 W Nifong Blvd, Bldg 1 • Columbia, MO 65203 Phone: 573-447-0292 www.CrockettEngineering.com

GEOTECHNICAL ENGINEERING REPORT

FOR

CLH ARCHITECTS, P.C.

VA HOSPITAL WAREHOUSE

COLUMBIA, MISSOURI

DECEMBER 31, 2020

Crockett GTL Project Number: G20602

1000 W Nifong Blvd. – Building 1 Columbia, Missouri 65203

(573) 447-0292

December 31, 2020

CLH Architects, P.C.

3705 North 200th Street Elkhorn, Nebraska 68022

Attn: Mr. Richard J. Onken, AIA

Re: Geotechnical Engineering Report

VA Hospital Warehouse Columbia, Missouri

Dear Mr. Onken:

Crockett Geotechnical – Testing Lab (Crockett GTL) has completed the geotechnical engineering services for the referenced project. This report should be read in its entirety. This report presents the results of our field explorations, laboratory testing, and recommendations for design and construction of the referenced project.

We appreciate the opportunity to be of service and look forward to working with you during the construction phase of this project. If you have any questions concerning this report, or if we may be of further service, please contact us.

Sincerely, Aaron Grimm, E.I.T. Eric H. Lidholm, P.E.

Project Manager Principal Engineer Missouri: E-23265

Enclosures cc: 1 – Client (.PDF)

1 – File

TABLE OF CONTENTS

1 INTRODUCTION

2 SITE AND PROJECT INFORMATION

2.1 Site Location and Description

2.2 Project Description

3 SUBSURFACE CONDITIONS

3.1 Field Exploration and Laboratory Testing

3.2 Encountered Subsurface Conditions

3.3 Groundwater

4 GEOTECHNICAL RECOMMEDATIONS

4.1 Uncontrolled Fill

4.2 Undocumented Fill

4.3 Shrink/Swell Prone Soils

4.3.1 Swell Test Results

4.3.2 Estimated Swell

4.3.3 Swell Discussion

4.4 Earthwork

4.4.1 Site Preparation

4.4.2 Structural Fill Material Requirements

4.4.3 Structural Fill Compaction Requirements

4.4.4 Grading and Drainage

4.4.5 Underground Utilities

4.4.6 Earthwork Construction

4.4.7 Temporary Excavations

4.5 Foundations

4.5.1 Shallow Foundation Design Recommendations

4.5.2 Shallow Foundation Construction Considerations

4.5.3 Pin Pile Foundation Recommendations

4.5.4 Pile Group Effect – Axially Loaded Piles

4.5.5 Pile Group Effect – Laterally Loaded Piles

4.6 New Floor Slab Areas

4.7 Seismic Considerations

4.8 Lateral Earth Pressures

4.9 Special Inspection Requirements

5 GENERAL COMMENTS

APPENDIX

Site Location Map Boring Location Plan Boring Logs Boring Log Legend and Nomenclature Swell Test Results

Geotechnical Engineering Report VA Hospital Warehouse

Columbia, Missouri Crockett Project Number: G20602

December 31, 2020

1 INTRODUCTION

Crockett Geotechnical - Testing Lab (CGTL) has conducted a geotechnical exploration for the proposed development. The purpose of our exploration was to:

Characterize and evaluate the subsurface conditions, Provide design and construction recommendations for:

o uncontrolled and undocumented fill o shrink/swell prone soils o earthwork o foundations o new floor slabs on-grade o seismic considerations o lateral earth pressures o special inspection requirements

2 SITE AND PROJECT INFORMATION

2.1 SITE LOCATION AND DESCRIPTION

Item Description

Location

This project is located at the existing VA Hospital Warehouse facility located at 800 Hospital Drive in Columbia, Missouri.

Specifically the project site is located approximately 200 feet east of the intersection of Tiger Avenue and East Stadium Boulevard in Columbia, Missouri

A Site Location Map showing the approximate location of this project is included in the Appendix of this report

Approximate GPS Coordinates 38.936306, -92.329975

Existing improvements Existing warehouse and driving/loading areas

December 31, 2020 Page 2

VA Hospital Warehouse – Columbia, Missouri

Current ground cover Existing warehouse, pavement, grass

Existing topography The site has been altered significantly by prior site grading and construction activities

2.2 PROJECT DESCRIPTION

Proposed structure

The western half of the existing structure will be replaced by a two story structure

The eastern half of the existing structure will remain but may require retrofitting and additional support

Building Construction Steel framed with masonry block walls

Maximum Loads (provided) Column Loads: 185 kips

Strip Loads: 3.0 klf

Fished Floor Elevation (FFE)

723.3 feet (MSL) – obtained from a Boundary and Topography plan prepared by Engineering Surveys & Services and dated 6- 30-16

Grading (approximate) We anticipate general site grading to consist of less than approximately 3 feet of cut or fill

Slopes Final slopes are assumed to be no steeper than 3H:1V (Horizontal to Vertical)

Free-standing retaining walls None anticipated

Below grade areas Stem walls

3 SUBSURFACE CONDITIONS

3.1 FIELD EXPLORATION AND LABORATORY TESTING

Four (4) borings were drilled for this project at the approximate locations indicated on the Boring Location Plan included in the Appendix of this report. Additional information follows:

December 31, 2020 Page 3

Field Exploration

Boring Locations 1 Designated and staked by a Crockett GTL geotechnical engineer

Boring Elevations 1

The boring locations and elevations were obtained from a Boundary and Topographic Survey prepared by Engineering Surveys & Services and dated 6-30-16

Drill Rig CME45 track-mounted drill rig equipped with 4-inch solid stem augers

Sampling Methods 2 Representative samples were obtained using thin-walled tube sampling and split-barrel tube sampling procedures

1. The location and elevation of the borings should be considered accurate only to the degree implied by the means and methods used to define them

2. A CME automatic SPT hammer was used to advance the split-barrel sampler in the borings performed on this site

The samples were tagged for identification, sealed to reduce moisture loss and taken to our laboratory for further examination, testing, and classification. Information provided on the boring logs attached to this report includes material descriptions, consistency evaluations, boring depths, sampling intervals, and groundwater conditions. The borings were backfilled with auger cuttings prior to the drill crew leaving the site.

The field logs were prepared by the drill crew. Final logs included with this report represent the engineer’s interpretation of the field logs and include modifications based upon laboratory tests and observation made of the samples. Detailed information regarding the material encountered and the results of field sampling and laboratory testing are shown on the Boring Logs included in the Appendix of this report. The descriptions of the soil on the final boring logs are in general accordance with the Unified Soil Classification System which is included in the Appendix of this report.

3.2 ENCOUNTERED SUBSURFACE CONDITIONS

From the ground surface in borings B-1, B-3 and B-4 was topsoil that ranged in thickness from approximately 2 to 8-inches. From the ground surface in boring B-2 was approximately 8-inches of concrete. Surficial material thickness should be expected to vary between borings.

Underlying the topsoil in boring B-1 was uncontrolled fill. Uncontrolled fill is fill material that is variable in strength, density, moisture content, and composition. This particular uncontrolled fill appeared to drill as if it was comprised of construction debris. The boring was abandoned at a depth of 12.5 feet while still within the uncontrolled fill after encountering difficult drilling and impenetrable obstructions while drilling with 4-inch solid stem augers. The thickness and aerial

December 31, 2020 Page 4 extent of this uncontrolled fill could not be determined and should be expected to vary elsewhere on the site.

Underlying the concrete in boring B-2 was base rock that extended to approximate depth of

7.0 feet. Base rock thickness should be expected to vary elsewhere on this site.

Underlying the topsoil in borings B-3 and B-4 was undocumented fill. Undocumented fill is fill material that appears to be compacted to a relatively high degree but for which no compaction test records are available to verify satisfactory compaction and moisture control was achieved during construction of the fill. The undocumented fill extended to depths ranging from approximately 7.0 to 8.0 feet in these borings and should be expected to vary elsewhere on the site.

Underlying the base rock in boring B-2 and the undocumented fill in boring B-3 was native gravelly lean to fat clay or lean to fat clay that was visually identified as glacial drift. The glacial drift extended to depths ranging from approximately 13.5 to 19.0 feet in these borings.

Underlying the undocumented fill in boring B-4 was native shaley fat clay. The shaley fat clay extended to an approximate depth of 20.0 feet.

Underlying the glacial drift in borings B-2 and B-3 and the shaley fat clay in boring B-4 was weathered limestone. Auger refusal was achieved in these borings within the weathered limestone at depths ranging from approximately 12.5 to 19.3 feet.

Detailed descriptions of the encountered materials are listed on the individual boring logs included in the Appendix of this report. Strata lines indicate the approximate location of changes in material types. The transition between material types may be gradual.

3.3 GROUNDWATER

The boreholes were observed while drilling and after completion of drilling for the presence and level of groundwater. In addition, delayed groundwater levels were also obtained in some borings.

The groundwater levels observed are noted on the attached boring logs, and are summarized below:

Groundwater Levels

Boring Number

Depth to Groundwater (feet)

At Time of Drilling At End of Drilling After Completion of Drilling

B-1 6.0 Not encountered Not encountered @ ¼ hrs

December 31, 2020 Page 5

Groundwater Levels

Number

Depth to Groundwater (feet)

At Time of Drilling At End of Drilling After Completion of Drilling

B-2 Not encountered Not encountered Not encountered @ ¼ hrs

B-3 Not encountered Not encountered Not encountered @ ¼ hrs

B-4 Not encountered Not encountered Not encountered @ ¼ hrs

Due to the low permeability of the soils encountered in the borings, a relatively long period of time may be necessary for a groundwater level to develop and stabilize in a borehole in these materials. Long term observations in piezometers or observation wells sealed from the influence of surface water are often required to define groundwater levels in materials of this type.

Pockets, lenses, and stringers of sand are sometimes encountered in the soil types encountered in the vicinity of the referenced project. These sand pockets are normally discontinuous and often contain water of variable quality and quantity. These sand pockets may be encountered during foundation excavation.

Perched groundwater can develop over low permeability soil or rock strata. This possibility should be considered when developing design and construction plans and specifications for the project. Groundwater levels depend on seasonal and climatic variations and may be present at different levels in the future. In addition, without extended periods of observation, accurate groundwater level measurements may not be possible, particularly in low permeability soils.

The boreholes were backfilled prior to departing the project site. Groundwater records are indicated on the boring logs included in the Appendix of this report.

4 GEOTECHNICAL RECOMMEDATIONS

4.1 UNCONTROLLED FILL

Uncontrolled fill was encountered in boring B-1 which was located about 27 feet west-northwest of the northwestern corner of the existing warehouse structure. Uncontrolled fill is fill material that is variable in strength, density, moisture content, and composition. This particular uncontrolled fill appeared to drill as if it was comprised of clay and construction debris. The boring was abandoned at 12.5 feet while still within the uncontrolled fill due to difficult drilling conditions and impenetrable obstructions while drilling with 4-inch solid stem augers. The

December 31, 2020 Page 6 thickness and aerial extent of the uncontrolled fill could not be determined and should be expected to vary elsewhere on the site. The uncontrolled fill as encountered in boring B-1 is not suitable for the support of foundations and/or floor slabs.

4.2 UNDOCUMENTED FILL

Undocumented fill was encountered in boring B-3 and B-4 to depths ranging from about 7.0 to

8.0 feet and base rock was encountered in boring B-2 to a depth of about 7.0 feet. These borings were located immediately south of the existing warehouse structure. It is not known if undocumented fill is present within the building footprint. Undocumented fill is fill material that appears to be compacted to a relatively high degree but for which no compaction test reports are available to verify satisfactory compaction and moisture control was achieved throughout the fill area. The undocumented fill, as encountered in borings B-2 through B-4, is not recommended for support of foundations under the anticipated structural loads.

4.3 SHRINK/SWELL PRONE SOILS

The following recommendations are for new floor slab on grade areas. Soil that has the capability to shrink or swell with variations in moisture content is present on this site. This report provides recommendations to help mitigate the effects of soil shrinkage and expansion.

However, even if these procedures are followed, some movement and at least minor cracking in the structure should be anticipated. The severity of cracking and other cosmetic damage such as uneven floor slabs will probably increase if any modification of the site results in excessive wetting or drying of the expansive soils. Eliminating the risk of movement and cosmetic distress may not be feasible, but it may be possible to further reduce the risk of movement if significantly more expensive measures are used during construction.

The procedures for constructing a low volume change zone, as recommended in this report, may not eliminate all future subgrade volume change and resultant floor slab movements.

However, the procedures outlined should significantly reduce the potential for subgrade volume change. Additional reductions in floor slab movements could be achieved by using a thicker low volume change zone. Details regarding this low volume change zone are provided in the Floor Slab section of this report. Any compacted structural fill placed in the upper 30-inches beneath new floor slab areas should meet the requirements for Low Volume Change (LVC) Material which is defined in the Earthwork section of this report.

In addition, all grades must provide effective drainage away from the building during and after construction. Water permitted to pond next to the building can result in greater soil movement and can result in unacceptable structural performance. After building construction has been completed, we recommend verifying final grades to document effective drainage has been

December 31, 2020 Page 7 achieved. Grades around the structure should also be periodically inspected and adjusted as necessary, as part of the structure’s maintenance program.

4.3.1 Swell Test Results

Two (2) swell tests were performed on a thin-walled tube sample to help evaluate the potential for soil swell. The results of this test follow:

Swell Test Results 1

Number

Sample Number

Sample Depth, ft

Confining Pressure, psf

Measured Swell, %

B-3 S-1 2.0 60 3.2

B-4 S-1 2.0 60 3.3

1. Additional results and details are provided on the One-Dimensional Swell Potential of Cohesive Soils report(s) included in the Appendix of this document

4.3.2 Estimated Swell

A swell estimation technique that uses soil index properties (liquid limit, dry density, and moisture content) was utilized to evaluate the potential for swell of the existing soils at the floor slab on-grade level. Based upon the results of this method, the potential swell of the existing near surface soils is estimated to in the range of 1.0 to 5.25 and averaged about 3.0%.

4.3.3 Swell Discussion

Literature indicates swell greater than 1.5% is considered high, or critical. Swell less than 0.5% is considered low or non-critical. Swell on the order of 0.5% to 1.5% is considered marginal.

Because of the estimated swell potential of the near surface soils, differential movement of lightly loaded, grade supported structures (i.e. floor slabs) is possible.

4.4 EARTHWORK

We recommend the exposed subgrade be thoroughly evaluated before the start of any fill operations. We recommend the geotechnical engineer be retained to evaluate the bearing material for the foundations and subgrade soils. Subsurface conditions, as identified by the field and laboratory testing programs have been reviewed and evaluated with respect to the proposed project plans known to us at this time.

4.4.1 Site Preparation

All unsuitable material should be removed from the construction areas prior to placing structural fill. After stripping and grubbing, the site should be proofrolled to aid in locating loose or soft

December 31, 2020 Page 8 areas. Proofrolling can be performed with a loaded tandem axle dump truck. Soft, wet, dry and low-density soil should be removed or be moisture conditioned and recompacted in place as structural fill prior to placing new structural fill.

4.4.2 Structural Fill Material Requirements

Compacted structural fill should consist of approved materials free of organic matter and debris.

Frozen material should not be used and fill should not be placed on a frozen subgrade. A sample of each material type should be submitted for evaluation prior to use.

Structural Fill Material Requirements

Material Type USCS Classif ication Acceptable Uses

Lean Clay and Clayey Sand CL & SC (LL<40) All locations

Lean to Fat Clay CL-CH (40<LL<50) > 30-inches below floor slab

Fat Clay CH (LL≥50+) > 30-inches below floor slab

Low Volume Change Material

Similar to MoDOT Type 1 or 5 crushed limestone aggregate, limestone screenings, or granular material such as sand, gravel or crushed stone containing at least 18% low plasticity fines

Low plasticity cohesive soil or granular soil having at least 18% low plasticity fines

Can also consist of soil treated with chemicals (hydrated lime, Code-L, etc.)

4.4.3 Structural Fill Compaction Requirements

Structural Fill Compaction Requirements

Soil Fill Lif t Thickness

9 inches or less when using heavy self-propelled compaction equipment

6-inches or less when using hand guided or light self-propelled equipment

December 31, 2020 Page 9

Structural Fill Compaction Requirements

Compaction Requirements 1, 2

95% of standard Proctor dry density (ASTM D-698)

1. We recommend engineered fill be tested for moisture content and compaction during placement. Should the results of the in-place density tests indicate the specified moisture or compaction limits have not been met, the area represented by the test should be reworked and retested as required until the specified moisture and compaction requirements are achieved

2. As stated within ASTM D698, this procedure is intended for soils with 30% or less material larger than ¾”. Accordingly, we recommend full time proof-roll observation be performed instead of moisture density testing for materials containing more than 30% aggregate retained on the ¾“ sieve

Compaction Moisture Content Requirements

Lean to Fat Clay and Fat Clay

Optimum moisture content (OMC) to 4% above the standard Proctor optimum moisture content

Lean Clay and Silt 2% below to 3% above standard Proctor OMC

Granular Workable moisture content. Shall not pump when proofrolled

4.4.4 Grading and Drainage

Final surrounding grades should be sloped away from the structure on all sides to prevent ponding of water. Gutters and downspouts that drain water a minimum of 10 feet beyond the footprint of the proposed structure is recommended. This can be accomplished through the use of splash-blocks, downspout extensions, and flexible pipes designed to attach to the end of the downspout. Flexible pipe should only be used if it is daylighted in such a manner that it gravity-drains collected water. Splash-blocks should also be considered below hose bibs and water spigots.

4.4.5 Underground Utilit ies

Underground utilities can provide a pathway for water to migrate below at-grade slabs. Drain and utility pipes beneath at-grade slabs should have tight joints to prevent leakage. If utility trenches are backfilled with relatively free-draining granular material, they should be effectively sealed to restrict water intrusion and flow through the trenches that could migrate below the structure and at-grade slabs. In addition, we recommend constructing an impermeable cut-off consisting of an effective clay plug at least 3 feet in length where underground utilities enter or exit the perimeter of the structure.

December 31, 2020 Page 10

With the exception of individual service lines to the building that intersect foundations perpendicularly, below grade utilities should not be located within the stress influence zone of the building foundations. Accordingly, below grade utilities should be located outside a zone extending 45-degrees downward and outward from the edge of the footings.

4.4.6 Earthwork Construction

In periods of dry weather, the surficial soils may be of sufficient strength to allow fill construction on the stripped and grubbed ground surface. However, unstable subgrade conditions could develop if the soils are wet or subjected to repetitive construction traffic. Should unstable subgrade conditions be encountered, stabilization measures will need to be employed.

Upon completion of filling and grading, care should be taken to maintain the subgrade moisture content prior to construction. Construction traffic over the completed subgrade should be avoided to the extent practical. The site should also be graded to prevent ponding of surface water on the prepared subgrades or in excavations. If the subgrade should become frozen, desiccated, saturated, or disturbed, the affected material should be removed or these materials should be scarified, moisture conditioned, and recompacted prior to construction.

The geotechnical engineer should be retained during the construction phase of the project to observe earthwork/fill placement and to perform necessary tests and observations during subgrade preparation; proof-rolling; placement and compaction of structural fills; backfilling of excavations into the completed subgrade, and just prior to construction.

4.4.7 Temporary Excavations

The Occupational Safety and Health Administration (OSHA) has developed regulations to provide for the safety of workers entering excavations. Temporary excavations will probably be required during grading operations. All operations should be performed under the supervision of qualified site personnel in accordance with OSHA Excavation and Trench Safety Standards.

4.5 FOUNDATIONS

Due to the anticipated structural loads and corresponding unsatisfactory settlement expected if a shallow foundation system is utilized to carry the loads, we recommend a deep foundation system be utilized. This would likely involve the use of a pin pile system such as micro-piles or push-piles to provide the additional support needed by the existing foundation system.

Lightly loaded incidental foundations unrelated to the structural support of the warehouse structure can be supported by a shallow spread-footing foundation system bearing on suitable

December 31, 2020 Page 11 native soil, thoroughly investigated and approved undocumented fill or on new structural fill.

Design recommendations and construction considerations for shallow foundations follow:

4.5.1 Shallow Foundation Design Recommendations

Design recommendations for lightly loaded incidental shallow foundations are as follows:

Shallow Foundation Design Recommendations

Allowable bearing pressure

Isolated foundations Continuous foundations Allowable overstress for transient loads (i.e. snow, wind, seismic)

1. Assumes all foundations will bear directly upon suitable native soil, thoroughly investigated and approved undocumented fill or on new structural fill

2,000 psf 1,700 psf

33%

Minimum foundation dimensions

Isolated foundations Continuous foundations

30 inches

12 inches

Ultimate passive pressure (equivalent f luid pressure)

1. The sides of the spread footing foundation excavations must be nearly vertical and the concrete should be placed neat against the vertical faces for the passive earth pressure values to be valid

2. Passive resistance in the frost zone should be neglected

3. Some movement of the footing will be required to mobilize resistance from passive pressure and sliding friction

270 pcf

Ultimate coeff icient of sliding friction 0.32

Minimum embedment below f inished grade for frost protection 30 inches

Uplif t Resistance

Soil Total Unit Weight Concrete Total Unit Weight

1. Only the soil directly overlying the foundation should be used for uplift resistance

2. Unit weight values do not include factors of safety

3. Assumes foundations are drained and are constructed above the highest groundwater level

120 pcf 150 pcf

Approximate Foundation Settlement

Total Differential

1. Assumes maximum footing size of 5.0 feet for isolated foundations and 1.5 foot for continuous foundations

< 1 inch

< ¾ inch

December 31, 2020 Page 12

4.5.2 Shallow Foundation Construction Considerations

The base of all foundation excavations should be free of water and loose soil and rock prior to placing concrete. Concrete should be placed soon after excavating to reduce bearing soil disturbance. Should the soil at the foundation bearing level become excessively dry, disturbed, saturated, or frozen the affected soil should be removed prior to placing concrete. Place a lean concrete mud-mat over the bearing soils if the excavations must remain open over night or for an extended period of time. It is recommended the geotechnical engineer be retained to observe and test the soil foundation bearing materials.

Groundwater was encountered in some of the borings and conditions may develop such that it may be encountered during foundation excavation. In addition, some surface and/or perched groundwater may enter foundation excavations during construction. It is anticipated any water entering foundation excavations from these sources can be removed using sump pumps or gravity drainage.

If unsuitable bearing soils are encountered in footing excavations, the excavations should be extended deeper to suitable soils and the footings should bear directly on these soils at the lower level or on lean concrete backfill placed in the excavations. The footings could also bear on properly compacted backfill extending down to the suitable soils. Overexcavation for compacted backfill placement below footings should extend laterally beyond all edges of the footings at least 8 inches per foot of overexcavation depth below footing base elevation. The overexcavation should then be backfilled up to the footing base elevation with well graded granular material placed in lifts of 9 inches or less in loose thickness and compacted to at least 98 percent of the material's maximum standard effort maximum dry density (ASTM D 698). The lean concrete backfill and overexcavation-and-backfill procedures are described in the diagram below.

December 31, 2020 Page 13

4.5.3 Pin Pile Foundation Recommendations

A pin-pile foundation system could be considered to supplement the load carrying capability of new and existing foundations. Many of these pin-pile systems are proprietary in nature and require specialized contractors for installation. Further, pin-pile foundation elements are usually part of the foundation contractor’s design-build system. Therefore, the subsurface exploration information contained in this report should be provided to the foundation contractors for detailed analysis and design and cost information.

Feasible types of pin pile elements could be broadly categorized as being installed by statically pushing the structural element into place or by drilling the structural element into place.

Considering the type of soils encountered in the borings, it is our professional opinion that a drilled system is preferable at this site.

Support of the pin-piles should be derived from the underlying limestone bedrock. The bedrock contact elevation, as encountered in the borings drilled for this investigation, was within the range of elevation 704.5 feet to 708.0 feet; however, the bedrock elevation could change abruptly over small horizontal distances. To account for this possibility, the project specifications should allow adjustment of the pile lengths in the field to ensure appropriate refusal criteria are achieved for end bearing in suitable bedrock.

We recommend a CGTL engineer or their representative be present on a full-time basis during installation of pin-piles to evaluate the materials removed from the excavations (if applicable) and to evaluate that proper construction procedures are used determine when adequate capacity has been developed, to observe the base of the drilled pier to determine the cuttings have been adequately removed, and also to observe the concreting techniques.

4.5.4 Pile Group Effect – Axially Loaded Piles

Piles should be spaced a minimum of 3 diameters center-to-center. Closer spacing may require a reduction in axial load capacity. Axial capacity reduction can be determined by comparing the allowable axial capacity determined from the sum of individual piles in a group versus the capacity calculated using the perimeter and base of the group acting as a unit. The lesser of the two capacities should be used in design.

4.5.5 Pile Group Effect – Laterally Loaded Piles

Laterally loaded piles behave as a group when center to center spacing is less than 8 diameters in the direction of loading. Allowable passive resistance provided by a row of piles in line with the direction of the load should be reduced as determined by multiplying the individual lateral

December 31, 2020 Page 14 resistances of the piles by the number of piles in line and the appropriate reduction factor provided in the following table:

Pile Group Effect 1

Centerline to Centerline Pile Spacing in Direction of Loading

(B = Pile Width)

Group Reduction

Factor

8B 1.0

7B 1.4

6B 1.8

5B 2.2

4B 2.6

3B 3.0

1. Obtained from: Design of Pile Foundations, EM 1110-2-2906, 15 January 1991

Lateral loads acting perpendicular to a row of piles with center-to-center spacing of 3 diameters or less will cause the foundations to react essentially as a vertical wall. For this case, the lateral earth pressures provided in the Lateral Earth Pressures section of this report should be used for the projected pile diameter. With spacing of greater than 3 diameters, the values provided in the previous table for individual piles may be used.

4.6 NEW FLOOR SLAB AREAS

Active soils that are prone to volume change with variations in moisture content are present near the anticipated at-grade floor slab subgrade level. Risk associated with construction on potentially expansive subgrade soils must be assumed by the owner. These risks can be reduced, but not eliminated, by constructing a zone of low volume change material below the floor slab.

New Floor Slab Area Design Recommendations 1, 2

New floor slab support 30-inch low volume change zone

Modulus of subgrade reaction

For point loading conditions

100 (psi/in)

December 31, 2020 Page 15

New Floor Slab Area Design Recommendations 1, 2

Aggregate base course/capillary break

Free draining granular material Free-draining granular material should have less than 5 percent fines

(material passing the #200 sieve)

4 to 6 inches

Aggregate base course can be considered as part of the low volume change zone

1. Floor slabs should be structurally independent of any building footings or walls to reduce the possibility of floor slab cracking caused by differential movement between the slab and foundation. However, if floor slabs are tied to perimeter walls or turn-down slabs to meet structural or other construction objectives, our experience indicates that any differential movement between the walls and slabs will likely be observed in adjacent slab expansion joints or slab cracks that occur beyond the length of the structural dowels. The structural engineer should account for this potential differential movement through use of sufficient control joints, appropriate reinforcing or other means

2. If the subgrade should become desiccated or saturated prior to construction of floor slabs, the affected material should be removed or the materials scarified, moistened, and recompacted. Care should be taken to maintain the recommended subgrade moisture content and density until construction of the building floor slabs

Control joints should be utilized in the slab to help control the location and extent of cracking.

For additional recommendations, refer to the ACI Design Manual. Joints or any cracks that develop should be sealed with a water-proof, non-extruding, compressible compound specifically recommended for heavy duty concrete pavement and wet environments.

The use of a vapor retarder should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet, or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer should refer to ACI 302 and/or ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder.

4.7 SEISMIC CONSIDERATIONS

The International Building Code and ASCE 7 requires the average properties in the upper 100 feet of the subsurface profile be determined for seismic site classification. The drilling scope performed for this project had borings that extended to a maximum depth of 19.3 feet. As such, we provide the following seismic site classification:

Seismic Site Classif ication

Code Used International Building Code & ASCE 7

Site Classif ication C

December 31, 2020 Page 16

Additional exploration to greater depths could be considered to confirm the conditions below the current depth of exploration. Alternatively, a geophysical exploration could be utilized in order to attempt to justify a more favorable seismic site class.

4.8 LATERAL EARTH PRESSURES

Reinforced concrete walls with unbalanced backfill levels may be utilized on this site. Walls should be designed using the earth pressures indicated in the following table. Earth pressures will be influenced by structural design of the walls, conditions of wall restraint, methods of construction and/or compaction and the strength of the materials being restrained. Two wall restraint conditions are shown. Active earth pressure is commonly used for design of free-standing cantilever retaining walls and assumes wall movement. The "at-rest" condition assumes no wall movement. The recommended design lateral earth pressures do not include a factor of safety and do not provide for possible hydrostatic pressure on the walls.

Earth Pressure Coeff icients

Backf ill Type Active (Ka) At Rest (Ko) Passive (Kp)

Cohesive

Equivalent Fluid Unit Weights 50 pcf 70 pcf 280 pcf

Granular

Equivalent Fluid Unit Weights 40 pcf 60 pcf 360 pcf

December 31, 2020 Page 17

Earth Pressure Coeff icients

Backf ill Type Active (Ka) At Rest (Ko) Passive (Kp)

Surcharge Pressure, P1 (psf)

Cohesive

Granular

(0.42)S

(0.33)S

(0.58)S

(0.46)S

Earth Pressure, P2 (psf)

Cohesive

Granular

(50)H

(40)H

(70)H

(55)H

Sliding Resistance 0.32 (coefficient of friction)

The values are applicable when the surface of the backfill behind the wall is horizontal. Increased values will result with steeper than horizontal slopes

No safety factor included in soil parameters Does not include loading from heavy compaction equipment No hydrostatic pressures acting on wall Backfill compacted to at least 95% standard Proctor dry density, or at least 80% relative density, as appropriate for material type Soil backfill unit weight a maximum of 120 pcf No dynamic loading For active earth pressure, wall must rotate about base, with top lateral movements of about 0.002 H to 0.004

H, where H is wall height For passive earth pressures to develop, the wall must move horizontally Ignore passive pressure in the frost zone For the granular values to be valid, the granular backfill must extend out from the base of the wall at an angle of at least 45 and 60 degrees from vertical for the active and passive cases, respectively Exterior granular backfill should be capped with approximately 2 feet of cohesive soil to reduce the potential for surface water infiltration into the granular backfill Uniform surcharge, where S is surcharge pressure

We recommend all below-grade walls be provided with a drainage system. A minimum 4-inch diameter, perforated drain pipe should be placed at the foundation level. Granular drainage material, consisting of 1-inch clean crushed rock, classified as GP by ASTM D 2487, with less than 5 percent passing the No. 200 sieve, should be placed a minimum of 6 inches in all directions around the drainage pipe. Synthetic filter fabric, such as Mirafi 140N or equivalent, should encapsulate the drainpipe and granular drainage material.

The pipe should be sloped to drain by gravity or through weep holes located on approximately 10-foot centers for above-grade retaining walls, or to a sump with a pump for below-grade walls where positive drainage by gravity cannot be achieved. Any interior sumps must be isolated “watertight” from the interior subgrade to prevent the movement of moisture from the sump into the underlying soils.

December 31, 2020 Page 18

4.9 SPECIAL INSPECTION REQUIREMENTS

The following items require special inspections in accordance with Chapter 17 of the International Building Code:

Schedule of Special Inspection Services 1, 2

Material/Activity Service Applicable to this Project

Y/N Extent

1705.6 Soil Y

Verify materials below shallow foundations are adequate to achieve the design bearing capacity

Field Inspection Y Periodic

Verify excavations are extended to proper depth and have reached proper material

Field Inspection Y Periodic

Perform classification and testing of controlled fill materials. Field Inspection Y Periodic

Verify use of proper material, densities, and lift thicknesses during placement and compaction of controlled fill

Field Inspection Y Continuous

Prior to placement of controlled fill, observe subgrade and verify site has been prepared properly

Field Inspection Y Periodic

1705.7 Driven Deep Foundations Y

1705.8 Cast-In-Place Deep Foundations Y

Observe drilling operations and maintain complete and accurate records for each element

Field Inspection Y Continuous

Verify placement locations and plumbness, confirm element diameters, bell diameters (if applicable), lengths, embedment into bedrock (if applicable), and adequate end bearing strata capacity. Record concrete or grout volumes

Field Inspection Y Continuous

For concrete elements, perform additional inspections in accordance with section 1705.3

See section 1705.3

Y See section 1705.3

Perform additional inspections and tests in accordance with the construction documents

Field Inspection and Testing

Y In accordance with the construction documents

1705.9 Helical Pile Foundations N

1. Testing and inspections services shall be performed by an approved agency in general accordance with section 1703 of the International Building Code

2. This section references 2015 IBC. Other code years may have a differing section number for concrete elements

The contractor shall request special inspection of the items listed above prior to those items becoming inaccessible and unobservable due to the progression of work.

December 31, 2020 Page 19

5 GENERAL COMMENTS

The recommendations provided herein are for the exclusive use of our client. Our recommendations are specific only to the project described herein and are not meant to supersede more stringent requirements of local ordinances or codes. The recommendations are based on subsurface information obtained at our boring locations, sample locations, our understanding of the project as described in this report, and geotechnical engineering practice consistent with the current standard of care. No warranty is expressed or implied. CGTL should be contacted if conditions encountered are not consistent with those described.

CGTL should be provided with a set of final plans and specifications, once they are available, to review whether our recommendations have been understood and applied correctly and to assess the need for additional exploration or analysis. Failure to provide these documents to CGTL may nullify some or all of the recommendations provide herein. In addition, any changes in the planned project or changes in site conditions may require revised or additional recommendations on our part.

The final part of our geotechnical service should consist of direct observation during construction to observe that conditions actually encountered are consistent with those described in this report and to assess the appropriateness of the analyses and recommendations contained herein. CGTL cannot assume liability or responsibility for the adequacy of recommendations without being retained to observe construction.

APPENDIX

PROJECT NO.: G20602

SITE LOCATION MAP

VA HOSPITAL WAREHOUSE

COLUMBIA, MISSOURI

Prepared By:

1000 W. Nifong Blvd, Building 1 Columbia, MO 65203

573-447-3981 www.CrockettGTL.com

Project Site

Prepared By:

1000 W. Nifong Blvd, Building 1 Columbia, MO 65203

573-447-3981 www.CrockettGTL.comPROJECT NO: G20602

BORING LOCATION PLAN

VA HOSPITAL WAREHOUSE

COLUMBIA, MISSOURI

B-3

B-2

B-1

B-4

ST

ST

SPT

5-3-5 (8)

105 22

722.5

710.5

0.5

12.5

TOPSOIL (6-inches)

UNCONTROLLED FILL: Clay soil, dark brown and brown, trace to with gravel, mixed with apparent construction debris

--: with gravel to gravelly

--: becomes gravelly, with possible cobbles and boulders

--: obstructions present from 10.0' - 12.5'

Hole abandoned at 12.5 feet.

Bottom of borehole at 12.5 feet.

NOTES Borehole backfilled upon completion

GROUND ELEVATION 723 ft MSL

LOGGED BY Grimm

DRILLING METHOD 4" SSA

HOLE SIZE 4"

DRILLING CONTRACTOR IPES GROUND WATER LEVELS:

CHECKED BY Lidholm

DATE STARTED 12/16/20 COMPLETED 12/16/20

AT TIME OF DRILLING 6.00 ft / Elev 717.00 ft

AT END OF DRILLING --- Not encountered

0.25hrs AFTER DRILLING --- Not encountered

D E

P T

H (f t)

S A

M P

LE

T

Y P

E N

U M

B E

R

B

LO

W C

O U

N T

S (N

V A

LU

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G R

A P

H

IC

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D R

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IT

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(p cf

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Q

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ID

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LA

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Y

IN

D E

X

ATTERBERG

LIMITS

U N

C

C O

M P

(p sf

R E

C O

V E

R Y

LE

N

G T

HMATERIAL DESCRIPTION

P E

N E

T R

O M

T E

R (p sf

BORING NUMBER B-1

PROJECT NAME VA Hospital Warehouse

PROJECT LOCATION Columbia, Missouri

CLIENT CLH Architects, P.C.

PROJECT NUMBER G20602

S A

M P

LE

L

E N

G T

H R

E P

O R

T

L A

T -L

O N

G T

E M

P

LA

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.G D

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Crockett GTL 1000 W Nifong Blvd Columbia, MO 65203 Telephone: 573-447-0292

ST

SPT

SPT

SPT

13-15-13 (28)

4-5-8 (13)

4-50/3"

722.8

716.5

704.5 704.3

0.7

7.0

19.0 19.3

CONCRETE (8-inches)

BASE ROCK: Gray, with fines

GRAVELLY LEAN TO FAT CLAY: Brown and gray, trace rust stains, trace sand and gravel (glacial drift)

--: zones of fat clay

WEATHERED LIMESTONE: Hard Refusal at 19.3 feet.

Bottom of borehole at 19.3 feet.

NOTES Borehole backfilled upon completion

GROUND ELEVATION 723.5 ft MSL

LOGGED BY Grimm

DRILLING METHOD 4" SSA

HOLE SIZE 4"

DRILLING CONTRACTOR IPES GROUND WATER LEVELS:

CHECKED BY Lidholm

DATE STARTED 12/16/20 COMPLETED 12/16/20

AT TIME OF DRILLING --- Not encountered

AT END OF DRILLING --- Not encountered

0.25hrs AFTER DRILLING --- Not encountered

D E

P T

H (f t)

S A

M P

LE

T

Y P

E N

U M

B E

R

B

LO

W C

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S (N

V A

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G R

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IC

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D R

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N

IT

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(p cf

M O

IS

T

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T E

N T

LI

Q

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ID

LI

M

IT

P

LA

S T

IC

LI

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IT

P

LA

S T

IC

IT

Y

IN

D E

X

ATTERBERG

LIMITS

U N

C

C O

M P

(p sf

R E

C O

V E

R Y

LE

N

G T

HMATERIAL DESCRIPTION

P E

N E

T R

O M

T E

R (p sf

BORING NUMBER B-2

PROJECT NAME VA Hospital Warehouse

PROJECT LOCATION Columbia, Missouri

CLIENT CLH Architects, P.C.

PROJECT NUMBER G20602

S A

M P

LE

L

E N

G T

H R

E P

O R

T

L A

T -L

O N

G T

E M

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LA

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Crockett GTL 1000 W Nifong Blvd

ST

ST

SPT

SPT

50/0"

50/0"

40 17 23

720.8

714.0

707.5

705.0

0.2

7.0

13.5

16.0

TOPSOIL (2-inches) UINDOCUMENTED FILL: Lean to fat clay, brown and dark brown, with gravel to gravelly

--: zones of fat clay

LEAN TO FAT CLAY: Gray and brown, trace sand and gravel (glacial drift)

WEATHERED LIMESTONE: Hard

Refusal at 16.0 feet.

Bottom of borehole at 16.0 feet.

12000

NOTES Borehole backfilled upon completion

GROUND ELEVATION 721 ft MSL

LOGGED BY Grimm

DRILLING METHOD 4" SSA

HOLE SIZE 4"

DRILLING CONTRACTOR IPES GROUND WATER LEVELS:

CHECKED BY Lidholm

DATE STARTED 12/16/20 COMPLETED 12/16/20

AT TIME OF DRILLING --- Not encountered

AT END OF DRILLING --- Not encountered

0.25hrs AFTER DRILLING --- Not encountered

D E

P T

H (f t)

S A

M P

LE

T

Y P

E N

U M

B E

R

B

LO

W C

O U

N T

S (N

V A

LU

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G R

A P

H

IC

LO

G

D R

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N

IT

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(p cf

M O

IS

T

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O N

T E

N T

LI

Q

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ID

LI

M

IT

P

LA

S T

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LI

M

IT

P

LA

S T

IC

IT

Y

IN

D E

X

ATTERBERG

LIMITS

U N

C

C O

M P

(p sf

R E

C O

V E

R Y

LE

N

G T

HMATERIAL DESCRIPTION

P E

N E

T R

O M

T E

R (p sf

BORING NUMBER B-3

PROJECT NAME VA Hospital Warehouse

PROJECT LOCATION Columbia, Missouri

CLIENT CLH Architects, P.C.

PROJECT NUMBER G20602

S A

M P

LE

L

E N

G T

H R

E P

O R

T

L A

T -L

O N

G T

E M

P

LA

T E

.G D

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2/

1/

2:

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P

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\G

2.

G P

J

Crockett GTL 1000 W Nifong Blvd

ST

ST

49 16 33

719.3

712.0

708.0

707.5

0.7

8.0

12.0

12.5

TOPSOIL (8-inches)

UNDOCUMENTED FILL: Lean to fat clay, brown and dark brown, trace sand and gravel

--: gravelly zones

SHALEY FAT CLAY: Light brown and tan, gray, trace to with rust stains

WEATHERED LIMESTONE: Hard

Refusal at 12.5 feet.

Bottom of borehole at 12.5 feet.

NOTES Borehole backfilled upon completion

GROUND ELEVATION 720 ft MSL

LOGGED BY Grimm

DRILLING METHOD 4" SSA

HOLE SIZE 4"

DRILLING CONTRACTOR IPES GROUND WATER LEVELS:

CHECKED BY Lidholm

DATE STARTED 12/16/20 COMPLETED 12/16/20

AT TIME OF DRILLING --- Not encountered

AT END OF DRILLING --- Not encountered

0.25hrs AFTER DRILLING --- Not encountered

D E

P T

H (f t)

S A

M P

LE

T

Y P

E N

U M

B E

R

B

LO

W C

O U

N T

S (N

V A

LU

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G R

A P

H

IC

LO

G

D R

Y U

N

IT

W T

(p cf

M O

IS

T

U R

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O N

T E

N T

LI

Q

U

ID

LI

M

IT

P

LA

S T

IC

LI

M

IT

P

LA

S T

IC

IT

Y

IN

D E

X

ATTERBERG

LIMITS

U N

C

C O

M P

(p sf

R E

C O

V E

R Y

LE

N

G T

HMATERIAL DESCRIPTION

P E

N E

T R

O M

T E

R (p sf

BORING NUMBER B-4

PROJECT NAME VA Hospital Warehouse

PROJECT LOCATION Columbia, Missouri

CLIENT CLH Architects, P.C.

PROJECT NUMBER G20602

S A

M P

LE

L

E N

G T

H R

E P

O R

T

L A

T -L

O N

G T

E M

P

LA

T E

.G D

T

2/

1/

2:

V

P

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C

T S

\G

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Crockett GTL 1000 W Nifong Blvd

BORING LOG LEGEND AND NOMENCLATURE

Sample Type Description Grain Size Terminology

AU Auger sample, disturbed, obtained from auger cuttings Boulders Larger than 12-inches

NR No recovery or lost sample Cobbles 3-inches to 12-inches

RC Rock core, diamond core bit, nominal 2-inch diameter rock sample (ASTM D 2113) Gravel Retained on #4 sieve to 3-inches

ST Thin walled (Shelby) tube sample, relatively undisturbed (ASTM D 1587) Sand Retained on #200 sieve but passes #4 sieve

SPT Split spoon sample, disturbed (ASTM D 1586) Silt or Clay Passes #200 sieve

VA Shear vane (ASTM D 2753)

Descriptor Relative Proportion of Sand and Gravel Relative Proportion of Fines

Trace Less than 15% by dry weight Less than 5% by dry weight

With 15% to 30% by dry weight 5% to 12% by dry weight

Modifier More than 30% by dry weight More than 12% by dry weight

Relative Density of Coarse grained Soils Consistency of Fine Grained Soils

Descriptive Term SPT N-Value, Blows/Foot Descriptive Term SPT N-Value, Blows/Foot Unconfined Compressive Strength, psf

Very Loose 0 - 3 Very Soft 0 – 1 0 – 500

Loose 4 – 9 Soft 2 – 3 501 – 1,000

Medium Dense 10 – 29 Medium 4 – 9 1,001 – 2,000

Dense 30 – 49 Stiff 10 – 29 2,001 – 4,000

Very Dense 50+ Very Stiff 30 – 49 4,001 – 8,000

Hard 50+ > 8,000

USCS Soil Classif ication System

Major Divisions Group

Symbol Group Name coarse grained soils more than

50% retained on #200 sieve gravel >50% of coarse fraction retained on #4 (4.75 mm) sieve clean gravel <5% small than #200 sieve

GW well-graded gravel, fine to coarse gravel

GP poorly graded gravel gravel with >12% fines

GM silty gravel

GC clayey gravel sand >50% of coarse fraction passes #4 (4.75 mm) sieve clean sand SW well-graded sand, fine to coarse sand

SP poorly graded sand sand with >12% fines

SM silty sand

SC clayey sand fine grained soils more than

50% passes #200 sieve silt and clay liquid limit < 50 inorganic ML silt

CL clay organic OL organic silt, organic clay silt and clay liquid limit ≥ 50 inorganic MH silt of high plasticity, elastic silt

CH clay of high plasticity, fat clay organic OH organic clay, organic silt highly organic soils PT peat

Weathering Description of Rock Properties

Fresh No discoloration. Not oxidized.

Slightly weathered Discoloration or oxidation of most surfaces but or short distance from fractures

Moderately weathered Discoloration or oxidation extends from fractures, usually throughout. All fractured surfaces are oxidized or discolored.

Severely weathered Discoloration or oxidation throughout. All fractured surfaces are oxidized or discolored. Surfaces are friable.

Decomposed Resembles a soil. Partial or complete remnant rock structure may be present.

Rock Quality Designator (RQD) Joint, Bedding, and Foliation Spacing in Rock

RQD, % Rock Quality Spacing Joints Bedding/Foliation

90 – 100 Excellent < 2-inches Very close Very thin

75 – 90 Good 2-inches – 1-foot Close Thin

50 – 75 Fair 1-foot – 3-feet Moderately Close Medium

25 – 50 Poor 3-feet – 10-feet Wide Thick

0 - 25 Very poor >10-feet Very Wide Very thick

Client Name: Project No.: Date:

Project Name:

Project Location:

SWELL: 3.2 %

Boring Number: 3 Sample No.: 1 Liquid Limit: 40

Sample Date: 12/21/20 Depth (ft): 2.0 Plastic Limit: 17

Sample Description: Plasticity Index: 23 (NP = Non Plastic)

Initial Moisture Content: 13.1 %

Initial Dry Density: 108.5 pcf

Surcharge Pressure: 60 psf

Test Procedure: Final Moisture Content: 20.2 %

Reviewed by: Final Dry Density: 104.5 pcf

TEST RESULTS

ASTM D 4546, Method B

UNDOCUMENTED FILL: Lean to fat clay, brown and dark brown, with

VA Hospital Warehouse

One-Dimensional Swell Potential of Cohesive Soils

ASTM D 4546

CLH Architects, P.C. G20602 12/31/20

Eric H. Lidholm, P.E.

gravel to gravelly

Columbia, Missouri

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100

S W

E

LL

c ha ng e)

TIME, hours

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

0.01 0.1 1 10 100

S W

E

LL

C ha ng e)

TIME (hours)

Clien…