GEOTECHNICAL ENGINEERING REPORT STONEGATE …

Office Locations: Junction City, KS / Kansas City, MO / Lenexa, KS / Salina, KS / Emporia, KS / Wichita, KS

GEOTECHNICAL ENGINEERING REPORT

STONEGATE ELEMENTARY SCHOOL

PAVEMENT IMPROVEMENTS

900 SOUTH FOXRIDGE DRIVE

RAYMORE, MISSOURI

Prepared For:

HTK ARCHITECTS, INC.

9300 West 110th Street

Overland Park, Kansas 66210

Prepared By:

KAW VALLEY ENGINEERING, INC.

14700 West 114th Terrace

Lenexa, Kansas 66215

January 11, 2021

Project No. C20G0818

January 11, 2021 C20G0818

Mr. Brad Kiehl

HTK Architects, Inc.

9300 West 110th Street

Overland Park, Kansas 66210

RE: GEOTECHNICAL ENGINEERING REPORT

STONEGATE ELEMENTARY SCHOOL

PAVEMENT IMPROVEMENTS

900 SOUTH FOXRIDGE DRIVE

RAYMORE, MISSOURI

Dear Mr. Kiehl:

This report presents the results of a subsurface exploration conducted for the referenced project.

This exploration was conducted in general accordance with our fee letter dated December 4,

2020. Authorization to proceed with geotechnical services for this site was provided previously.

The purpose of this study was to define the subsurface conditions at the site and develop

geotechnical information for the proposed improvements to the site.

EXECUTIVE SUMMARY

Information, conclusions, and recommendations which, in our opinion, are significant to the

design and construction of this project, are provided below. Additional details, the general

subsurface profile, other related items, and general information regarding the various phases of

our exploration are included in the main body of the report.

Typical pavement conditions encountered throughout the project consist of 4.8 to 8.5 inches of

asphalt pavement. The subgrade soils consisted of lean to fat (medium plastic), lean (low

plastic), and fat (high plastic) clays. Based upon the conditions encountered during the

exploration, it is our opinion the majority of existing pavement are of adequate thickness to be

milled and overlaid, if desired.

PROJECT AND SITE DESCRIPTION

The proposed Stonegate pavement improvement project includes parking lot and drive

improvements at the Stonegate Elementary School in Raymore, Missouri. The Stonegate

Elementary School is located at 900 South Foxridge Drive. Specific improvement plans include

the possible mill and overlay on the north, northwest, and west side of the existing school.

Traffic counts were not supplied at the time of this report. Minor grading changes are anticipated

for the proposed construction areas. The site and surrounding area are displayed on Plate 1.

Kaw Valley Engineering, Inc. Stonegate Elementary School – Raymore, Missouri – C20G0818

Geotechnical Engineering Report Page 2

FIELD EXPLORATION

The field exploration was performed on December 22, 2020 and included drilling nine test borings,

identified as C-1 through C-9. The boring locations were selected by Kaw Valley Engineering.

The boring locations are displayed on Plate 1.

The pavement was cored using an electric drill with diamond core barrel. The subgrade materials

were measured and sampled using hand augering equipment. Grab soil samples were obtained

using the cuttings at various locations. Dynamic cone penetration (DCP) tests were performed at

various locations to determine existing subgrade strengths. These results are included in

Appendix A.

The borings were logged in the field by the driller, based upon visual classifications of materials

encountered during drilling, as well as the driller’s interpretation of the subsurface conditions

between samples. Final conditions encountered included with this report represent the engineer’s

interpretation of the field logs and include revisions based upon results of the laboratory testing.

LABORATORY TESTING PROGRAM

The laboratory testing program was designed to determine the pertinent engineering and index

properties of the soil. Atterberg limits and moisture contents were determined for select soil

samples. Results of the laboratory tests are presented below. All tests were performed in general

accordance with applicable ASTM standards.

SUBSURFACE CONDITIONS

Stratigraphy. Typical pavement conditions encountered throughout the project consist of 4.8 to

8.5 inches of asphalt pavement. lean to fat (medium plastic), lean (low plastic), and fat (high

plastic) clays. The conditions encountered at the boring location are presented in Table 1 below.

Table 1 - Conditions Encountered

Core location

Asphalt

Thickness (in) Subgrade Material

C- 1 6.5 CH: Fat clay

C- 2 7.3 CL: Lean clay


C- 4 5.8 CL-CH: Lean to fat clay



C- 7 4.8 CL: Lean clay



The Atterberg limit and moisture test results performed on select soil samples are presented below

in Table 2.



Table 2 – Atterberg and Moisture Laboratory Test Results

Core Moisture Atterberg Limits Classification

Number Content LL PL PI

C-2 32.4 44 26 18 CL

C-4 29.2 48 21 28 CL-CH

C-6 30.8 48 27 21 CL-CH

C-8 32.9 66 23 43 CH

Dynamic cone penetration (DCP) tests were also conducted at various locations. These tests

indicated estimated in-place California Bearing Ratio (CBR) values in the subgrade ranging from

3 to 72. The CBR values are within normal values for subgrades in this geographic area. The data

sheets for these tests are included in Appendix A of this report.

Groundwater. Groundwater was not encountered within the depths explored. However, it should

be understood that the level of the groundwater may fluctuate due to rainfall and other climatic

factors, and that groundwater may or may not be present during construction or at other times

during the life of the project.

DESIGN CONSIDERATIONS AND RECOMMENDATIONS

The on-site soils at the pavement subgrade elevation are of low to high plasticity and are considered

to be swell sensitive. Therefore, KVE recommends low volume change imported materials or soil

stabilized onsite materials of the upper 8 inches in areas for which full depth replacement may be

utilized.

Site Preparation. Initial site preparation for the proposed project should commence with the

stripping and removal of any deleterious materials deemed unsuitable by the geotechnical

engineer.

If full depth replacement is utilized, the following recommendations should be adhered to.

Immediately following the removal of the upper 8 inches, the moisture content of the exposed soils

should be evaluated. Depending on the in-situ moisture content of the soils exposed, moisture

conditioning of the exposed grade may be required prior to proofrolling and/or fill placement. The

moisture content of the exposed grade in these fill areas should be adjusted to within the range

recommended for structural fill to allow the exposed material to be compacted to a minimum

density of 95 percent as determined by the standard Proctor compaction procedure. Extremely wet

or unstable areas that hamper compaction of the subgrade may require undercutting and

replacement with structural fill or other stabilization techniques.

Structural Fill. The existing on-site soils may be used as structural fill with the exception of 8

inches beneath the pavement’s base materials. Imported fill material, if required, should consist

of low swell potential cohesive soils with a liquid limit less than 45 and a plasticity index between

10 and 25. All fill soils should be free of topsoil, organic matter, rock fragments larger than 3

inches, and other deleterious materials. The geotechnical engineer should approve all fill

material. Approval requires that a moisture/density relationship and Atterberg limits be performed

for each proposed fill material prior to its placement. In lieu of importing low swell potential

materials, the on-site clay soils can be chemically modified. Crushed stone aggregate base similar

to KDOT AB-3 or MoDOT Type 5 may be utilized for low volume change materials.



All fill should be placed in lifts having a maximum loose lift thickness of 8 inches, and should be

compacted to a minimum of 95% of the material’s maximum dry density as determined by ASTM

D 698 (standard Proctor compaction). The moisture content of the fill at the time of compaction

should be within a range of 1% below optimum moisture to 3% above optimum moisture content

as defined by the standard Proctor compaction procedure. Moisture contents should be maintained

within this range until completion of the pavement.

Prior to placement of fill, sloping areas steeper than 5:1 (horizontal:vertical) should be benched to

reduce the potential for slippage between existing slopes and new fills. Benches should be level,

with vertical heights between 12 and 36 inches, and wide enough to accommodate compaction and

earth moving equipment.

All utility trenches should be backfilled with either on-site or imported fill material. Granular

materials such as clean sand or gravel should not be used to bed utilities or backfill trenches unless

the bottom of the trench is graded so that water flows away from the pavement.

Continuous observation by the geotechnical engineer or his representative should be maintained

during site preparation and compaction of all fill and backfill material.

Chemical Stabilization. If high plasticity soils are encountered within 8 inches of the pavement

base materials, they may be chemically stabilized using lime, cement, or fly ash. Scarify and

moisture condition each lift to a moisture content of 5 to 8% above optimum moisture. Add 5%

hydrated lime, 5% Portland cement, or 15% Type C fly ash by dry weight, and blend with moisture-

conditioned soil utilizing a Bomag pulvamixer or approved equivalent. Recompact each soil

mixture lift to a minimum dry density of 95% of the maximum dry density, with the moisture

content between optimum and 3% above optimum as determined by ASTM D 698. Compaction

of the chemically stabilized soil should be completed within 2 hours of the incorporation of the

chemical stabilizer. Stabilization of the pavement areas may be accomplished in one lift.

Pavement Sections. Based upon the conditions encountered during the exploration, it is our

opinion the majority of existing pavement have adequate thickness to be milled and overlaid. We

recommend an existing pavement thickness of a minimum of 5 inches in order to mill.

In areas of milling, KVE recommends milling 2 inches, sealing cracks and patches as needed, and

replacing with a minimum of 2 inches of asphalt. Some areas of full depth pavement replacement

may be required in the highly deteriorated areas. The subgrade replacement of 8 inches of low

volume change materials or stabilized onsite soils is required for the full depth pavement

replacement areas.

The CBR value for the soil types encountered on the site are typically estimated to be a minimum

of 3; therefore, the following 20-year life pavement sections are recommended for both flexible

and rigid pavements are presented in Table 3.



Table 3 – Recommended Pavement Sections for Full Depth Pavement Sections

Loading Type Concrete Asphaltic Concrete Light Traffic (employee/customer parking, and small

delivery truck

parking)

5″ Portland Cement Concrete

4″ Well Graded Granular Base

8" Low Volume Change Imported Materials

or Soil Stabilized Onsite Materials

6″ Hot-Mixed Asphalt Concrete



Heavy Traffic (delivery drives and

loading docks)

8″ Portland Cement Concrete

4″ Well Graded Granular Base



8″ Hot-Mixed Asphalt Concrete



Mixes selected for the Hot-Mix Asphalt Concrete alternate can be MoDOT SP125FEEF or APWA

Type 6-01. If a Marshall designed mix is desired, any 50-blow Marshall mix may be selected

meeting the aggregate and gradation requirements of APWA Type 2 or 3, MoDOT BP-1 or 2, or

other locally produced Marshall mix that is equivalent to KDOT BM-2. Any submitted 50-blow

Marshall mix design should also be checked for resistance to stripping during design using

AASHTO T 283 to determine if an antistripping agent is needed for the same asphalt concrete

chosen for the project. The index of retained strength shall exceed 75%.

Portland cement concrete for pavement, sidewalks, and curbs must meet the current requirements

of the Kansas City Metropolitan Materials Board specifications, the 2015 MoDOT Standard

Specifications for on-grade concrete.

Pavement in any dumpster area should be the Portland cement concrete section as recommended

in the truck access and drives section. Also, preventive maintenance action(s) may be needed for

the asphaltic concrete parking and drives in order to maintain the service condition (i.e. crack

sealing).

Landscaping. Consideration should be given to limiting landscaping and irrigation adjacent to

the pavement areas. Trees and large bushes can draw moisture from subgrade soils resulting in

settlement of pavements.

Excavations. Bedrock was not encountered within the depths of the borings, below proposed site

grading depths, and therefore is not anticipated to be present during to construction of the project.

Drainage. The site should be graded so that surface water flows away from the pavement area

and is not allowed to accumulate near the pavement.

OBSERVATION OF CONSTRUCTION

The conclusions and recommendations given in this report are based on interpretation of field

boring and laboratory data coupled with our experience. Variations may occur from conditions

observed within test borings; therefore, it is imperative to involve the geotechnical engineer in the

final design and construction process.



Field observation services are viewed as a continuation of the design process. Unless these services

are provided, the geotechnical engineer will not be responsible for improper use of

recommendations, or failure by others to recognize conditions which may be detrimental to the

successful completion of the project.

LIMITATIONS

The analyses, conclusions, and recommendations contained in this report are based on the site

conditions and project layout described herein and further assume that the conditions observed in

the exploratory borings are representative of the subsurface conditions throughout the site, i.e., the

subsurface conditions elsewhere on the site are the same as those disclosed by the borings. If,

during construction, subsurface conditions different from those encountered in the exploratory

borings are observed or appear to be present beneath excavations, we should be advised at once so

that we can review these conditions and reconsider our recommendations where necessary.

If there is a substantial lapse in time between the submittal of this report and the start of work at

the site, or if conditions or the project layout have changed due to natural causes or construction

operations at or adjacent to the site, we recommend that this report be reviewed to determine the

applicability of conclusions and recommendations considering the changed conditions and time

lapse.

We recommend that we be retained to review the project layout and those portions of plans and

specifications which pertain to foundations and earthwork to determine if they are consistent with

our findings and recommendations. In addition, we are available to observe construction,

particularly site grading, earthwork, and foundation construction. We would be available to make

other field observations as may be necessary.

This report was prepared for the exclusive use of the owner, architect, and engineer for evaluating

the design of the project as it relates to the geotechnical aspects discussed herein. It should be made

available to prospective contractors for information on factual data only and not as a warranty of

subsurface conditions included in the report. Unanticipated soil conditions may require that

additional expense be made to attain a properly constructed project. Therefore, some contingency

fund is recommended to accommodate such potential extra costs.

Site Plan and Boring Locations Plate 1a

STONEGATE ELEMENTARY SCHOOL900 South Foxridge DriveRaymore, Missouri Approved By: JAN Not to Scale Project No. C20G0818

North

C-1

C-2

C-3

C-4

C-5

C-6

C-7C-8

C-9

A P P E N D I X A

DYNAMIC PENETRATION TEST RESULTS

Project #:

mm

Number of Blows

Cumulative Blows (mm)

Penetration Between Readings

(mm)

Penetration per Blow

(mm)

DCP Index mm/blow

CBR

1 1 15 15.0 15.00 141 2 14 14.0 14.00 151 3 11 11.0 11.00 201 4 12 12.0 12.00 181 5 8 8.0 8.00 281 6 8 8.0 8.00 281 7 12 12.0 12.00 181 8 8 8.0 8.00 281 9 8 8.0 8.00 281 10 9 9.0 9.00 251 11 10 10.0 10.00 221 12 11 11.0 11.00 201 13 9 9.0 9.00 251 14 10 10.0 10.00 221 15 9 9.0 9.00 251 16 9 9.0 9.00 251 17 10 10.0 10.00 221 18 11 11.0 11.00 201 19 8 8.0 8.00 281 20 10 10.0 10.00 221 21 9 9.0 9.00 251 22 4 4.0 4.00 621 23 5 5.0 5.00 481 24 4 4.0 4.00 621 25 4 4.0 4.00 621 26 4 4.0 4.00 621 27 5 5.0 5.00 482 29 10 5.0 5.00 482 31 10 5.0 5.00 482 33 9 4.5 4.50 547 40 48 6.9 6.86 34

Kaw Valley Engineering, Inc.14700 West 114th TerraceLenexa, Kansas 66215(913) 894-5150 / (913) 894-5977 Fax

340345355365374422

310319323328332336

253262271281292300

196204213223234243

137148160168176188

Initial Reading: 108 Hammer Blow Factor: 1

Cumulative Penetration Reading

(mm)123

DCP DATA SHEET

Project Name : Stonegate Pavement Improvements C20G0818

Location : C-2 Date: 12/22/2020

Project #:

mm

Number of Blows



(mm)


(mm)

DCP Index mm/blow

CBR

3 3 44 14.7 14.67 142 5 27 13.5 13.50 162 7 31 15.5 15.50 142 9 31 15.5 15.50 142 11 41 20.5 20.50 102 13 46 23.0 23.00 92 15 47 23.5 23.50 92 17 49 24.5 24.50 82 19 52 26.0 26.00 82 21 62 31.0 31.00 62 23 50 25.0 25.00 82 25 40 20.0 20.00 102 27 32 16.0 16.00 132 29 30 15.0 15.00 142 31 25 12.5 12.50 172 33 24 12.0 12.00 182 35 21 10.5 10.50 212 37 19 9.5 9.50 232 39 19 9.5 9.50 232 41 19 9.5 9.50 232 43 17 8.5 8.50 272 45 15 7.5 7.50 312 47 15 7.5 7.50 312 49 17 8.5 8.50 272 51 6 3.0 3.00 852 53 7 3.5 3.50 722 55 7 3.5 3.50 722 57 7 3.5 3.50 722 59 12 6.0 6.00 392 61 13 6.5 6.50 3615 76 95 6.3 6.33 37


DCP DATA SHEET





(mm)74101132163204250297346398460510550582612637661682701720739756771786803809816823830842855950

Project #:

mm

Number of Blows



(mm)


(mm)

DCP Index mm/blow

CBR

2 2 30 15.0 15.00 142 4 21 10.5 10.50 212 6 14 7.0 7.00 332 8 13 6.5 6.50 362 10 14 7.0 7.00 332 12 13 6.5 6.50 362 14 14 7.0 7.00 332 16 16 8.0 8.00 282 18 19 9.5 9.50 232 20 25 12.5 12.50 172 22 32 16.0 16.00 132 24 6 3.0 3.00 852 26 83 41.5 41.50 42 28 52 26.0 26.00 82 30 37 18.5 18.50 112 32 31 15.5 15.50 142 34 31 15.5 15.50 142 36 27 13.5 13.50 162 38 25 12.5 12.50 172 40 22 11.0 11.00 202 42 21 10.5 10.50 212 44 21 10.5 10.50 212 46 19 9.5 9.50 232 48 18 9.0 9.00 252 50 14 7.0 7.00 332 52 16 8.0 8.00 282 54 15 7.5 7.50 312 56 17 8.5 8.50 272 58 13 6.5 6.50 369 67 59 6.6 6.56 3616 83 90 5.6 5.63 42


736751768781840930

627648669688706720

454491522553580605

237256281313319402

153167180194207221



(mm)132

DCP DATA SHEET



Project #:

mm

Number of Blows



(mm)


(mm)

DCP Index mm/blow

CBR

2 2 115 57.5 57.50 32 4 88 44.0 44.00 42 6 61 30.5 30.50 62 8 39 19.5 19.50 102 10 31 15.5 15.50 142 12 27 13.5 13.50 162 14 25 12.5 12.50 172 16 21 10.5 10.50 212 18 20 10.0 10.00 222 20 19 9.5 9.50 232 22 19 9.5 9.50 232 24 15 7.5 7.50 312 26 16 8.0 8.00 282 28 16 8.0 8.00 282 30 7 3.5 3.50 722 32 14 7.0 7.00 332 34 13 6.5 6.50 362 36 15 7.5 7.50 312 38 15 7.5 7.50 312 40 11 5.5 5.50 432 42 12 6.0 6.00 392 44 12 6.0 6.00 392 46 12 6.0 6.00 392 48 11 5.5 5.50 432 50 9 4.5 4.50 542 52 13 6.5 6.50 362 54 10 5.0 5.00 482 56 10 5.0 5.00 482 58 10 5.0 5.00 482 60 10 5.0 5.00 4810 70 49 4.9 4.90 49


730740750760770819

661673685697708717

586593607620635650

481501520539554570

277338377408435460



(mm)189

DCP DATA SHEET



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GEOTECHNICAL ENGINEERING REPORT STONEGATE …