Geotechnical_Report_BRIDGE_B104_0002.pdf

REPORT COVER PAGE

Geotechnical Engineering Report

Kickapoo Bridge Replacement

Near Horton, Kansas

March 7, 2023

Terracon Project No. 14225103.2

Prepared for:

Kickapoo Tribe c/o BG Consultants, Inc.

Manhattan, Kansas

Prepared by:

Terracon Consultants, Inc.

Topeka, Kansas

Terracon Consultants, Inc. 2016 SW 37 th Street Topeka, Kansas 66611

(785) 267 3310 terracon.com

REPORT COVER LETTER TO SIGN

March 7, 2023

Kickapoo Tribe c/o BG Consultants, Inc.

4806 Vue Du Lac Place

Manhattan, Kansas 66503

Attn: Mr. Brady Hedstrom, P.E.

P: (785) 712 2676

E: brady.hedstrom@bgcons.com

Re: Geotechnical Engineering Report

Kickapoo Bridge Replacement

130th Street over the Delaware River

Near Horton, Kansas

Terracon Project No. 14225103.2

Dear Mr. Hedstrom:

We have completed the Geotechnical Engineering services for the above referenced project. This study was performed in general accordance with Terracon Proposal No. P14225103 dated

December 21, 2022. This report presents the findings of the subsurface exploration and provides geotechnical recommendations concerning earthwork and the design and construction of foundations for the proposed project.

We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report or if we may be of further service, please contact us.

Sincerely, Terracon Consultants, Inc.

Michael A. Snapp, P.E. Jamie M. Klein, P.E.

Geotechnical Engineer Senior Associate

Kansas PE: 27005 Kansas PE: 22112

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REPORT TOPICS

INTRODUCTION

SITE CONDITIONS

PROJECT DESCRIPTION

GEOTECHNICAL CHARACTERIZATION

GEOTECHNICAL OVERVIEW

EARTHWORK

DEEP FOUNDATIONS

LATERAL EARTH PRESSURES

GENERAL COMMENTS

ATTACHMENTS

Note: This report was originally delivered in a web-based format. For more interactive features, please view your project online at client.terracon.com.

ATTACHMENTS

EXPLORATION AND TESTING PROCEDURES

SITE LOCATION AND EXPLORATION PLAN

EXPLORATION RESULTS

• Boring Logs with Laboratory Data

• GeoModel

• Rock Core Photo Log

SUPPORTING INFORMATION

• General Notes

• Unified Soil Classification System

• Description of Rock Properties

Note: Refer to each individual Attachment for a listing of contents.

http://client.terracon.com/

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Kickapoo Bridge Replacement

130th Street over the Delaware River

Near Horton, Kansas Terracon Project No. 14225103.2

March 7, 2023

INTRODUCTION

This report presents the results of our subsurface exploration and geotechnical engineering services performed for the proposed bridge replacement located where 130th Street crosses over the Delaware River approximately 7 miles northwest of Horton, Kansas. The purpose of these services is to provide information and geotechnical engineering recommendations relative to:

■ Subsurface soil and rock conditions ■ Site preparation and earthwork

■ Groundwater conditions ■ Foundation design and construction

The geotechnical engineering Scope of Services for this project included the advancement of

2 test borings to depths ranging from approximately 33.5 to 43 feet below existing site grades.

Maps showing the site and boring locations are shown in the Site Location and Exploration

Plans section. The results of the laboratory testing performed on soil samples obtained from the site during the field exploration are included on the boring logs in the Exploration Results section.

SITE CONDITIONS

The following description of site conditions is derived from our site visit in association with the field exploration and our review of publicly available geologic and topographic maps.

Item Description

Parcel Information

The project is located where 130th Street crosses over the Delaware River northwest of Horton, Kansas.

Approximate Coordinates: 39.696264, -95.662559

Existing

Improvements

Based upon provided plans, we understand the existing structure is a

70.5-foot steel girder span bridge.

Existing Topography

The roadway is elevated above the creek channel and associated low-lying areas with the road embankment having moderate to steep side-slopes.

Based on the provided plan/profile sheets, the creek channel is incised approximately 25 feet below 130th Street.

Kickapoo Bridge Replacement ■ Near Horton, Kansas

March 7, 2023 ■ Terracon Project No. 14225103.2

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PROJECT DESCRIPTION

Our initial understanding of the project was provided in our proposal and was discussed during project planning. A period of collaboration has transpired since the project was initiated, and our final understanding of the project conditions is as follows:

Item Description

Information Provided

Our understanding of the project is from conversation and email correspondence with the BG Consultants and provided Preliminary Plan and

Profile Sheets for Bridge B104.

Project Description

We understand the improvements at the project site are anticipated to include removal of the existing bridge and construction of a new, three-span reinforced concrete haunched slab (RCSH) bridge. Bridge B104 will be located along the existing roadway alignment and likely have span lengths of 36 ft.–48 ft.–36 ft.

We understand the abutments and the intermediate bents are planned to be supported by driven piles.

Grading/Slopes

Preliminary site grading plans were being develop during the exploration. We expect general site grading to include less than approximately 5 feet of cut and fill to possibly reshape the channel and side slopes of the existing road embankments.

Slope Stability

As there is an existing bridge present at the site, it may not be necessary to perform global slope stability analysis of the spill slopes unless the slopes are steepened. We could provide a proposal for these services upon request.

Terracon should be notified if any of the above information is inconsistent with the planned construction, especially the grading limits, as modifications to our recommendations may be necessary.

GEOTECHNICAL CHARACTERIZATION

Geology

The site is located within the Delaware River floodplain which typically consists of Quaternary aged alluvial (water-deposited) soils generally comprised of clay and sand/gravel materials. The soils overlie Carboniferous aged bedrock from the Wabaunsee Group. Based on our review of

Brown County geology, we believe the bedrock encountered in the borings is part of the Wood

Siding Formation which includes the Brownville Limestone, Pony Creek Shale, Grayhorse

Limestone, Plumb Shale, and Nebraska City Limestone Members.

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Subsurface Profile

We have developed a general characterization of the subsurface conditions based upon our review of the subsurface exploration, laboratory data, geologic setting and our understanding of the project. This characterization, termed GeoModel, forms the basis of our geotechnical calculations and evaluation of site preparation and foundations. Detailed conditions encountered at each exploration point are indicated on the individual logs. The individual boring logs and

GeoModel can be found in the Exploration Results section of this report. Stratification boundaries on the boring logs and GeoModel represent the approximate location of changes in stratum type; however, in situ the transition between native materials may be gradual while in existing fill changes could be abrupt.

Groundwater Conditions

The boreholes were observed while auger drilling for the presence and level of groundwater.

Groundwater was not observed in Boring B-1 nor observed in Boring B-2 prior to the introduction of drilling fluid. However, this does not necessarily mean the borings were completed above groundwater. A longer period of time may be required for groundwater to develop and stabilize in a borehole. Longer term observations in piezometers or observation wells, sealed from the influence of surface water, are often required to define groundwater levels.

We would generally expect the groundwater level at this site to be near or above the water level in the river. However, groundwater level fluctuations occur due to seasonal variations in the amount of rainfall, runoff, the water level in the river and other factors not evident at the time the borings were performed. In addition, perched water can develop over low permeability soil or rock strata.

Therefore, groundwater levels during construction or at other times in the life of the structure may be higher or lower than the observations made during our subsurface exploration. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project.

GEOTECHNICAL OVERVIEW

Based on the subsurface conditions, planned construction, and our analysis, it is our opinion the proposed bridge can be supported as planned by driven steel piles or straight sided drilled shafts.

All foundation elements would derive capacity from the underlying weathered shale or limestone bedrock. We anticipate pre-boring may be required for the driven piles or rock coring for drilled shafts to develop sufficient pile/shaft lengths for scour protection and/or lateral capacity.

With seasonal water level fluctuations in the Delaware River, it is difficult to predict the near surface groundwater conditions that will be present during construction. The potential for soft subgrade soils during earthwork activities for the project should be anticipated by the contractor.

Accordingly, stabilization of subgrade soils prior to placement of embankment soils should be

Responsive ■ Resourceful ■ Reliable 4 anticipated and considered when budgeting for the project. Additional considerations regarding stabilization are included in the Earthwork section of this report below. Further, the potentially shallow groundwater conditions resulting from the proximity to the river indicate that the contractor should be prepared for dewatering at the site.

We recommend the exposed subgrade be thoroughly evaluated after site stripping and the removal of unsuitable existing fill, but prior to the start of any fill operations. We recommend the geotechnical engineer be retained to evaluate and observe earthwork operations and foundation installation procedures. 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.

The recommendations presented in the following sections consider the proposed structure, site grading, and the location of the project are as outlined earlier within this report. Terracon should be contacted immediately if conditions are different than described as this may impact our recommendations.

EARTHWORK

Site Preparation

Once all cuts have been performed to accommodate the planned construction, the subgrade soils should be evaluated prior to placement of the new fill. Unsuitable materials, including vegetation, topsoil, construction debris and unsuitable fill should be removed to full depth. Wet or dry material should also be removed; if otherwise suitable, such materials can be moisture conditioned and placed with moisture and density control in engineered fills. The exact depth of remediation, if any, should be determined in the field during site grading based on the actual extent of unsuitable material encountered.

After stripping and removal of unsuitable soils (if any) the subgrade should be proof-rolled where possible to aid in locating loose or soft areas. Proof-rolling can be performed with a loaded tandem axle dump truck or other equipment providing an equivalent subgrade loading. Where proofrolling is not possible, we recommend the subgrade be evaluated by other means, possibly including the use of a steel T-probe, test pits, or Shelby tube samples. Soft, dry and low-density soil should be removed, compacted in place prior to placing fill or stabilized as recommended in the Earthwork Construction Considerations section.

New Fill Materials and Placement

Newly placed engineered fill should consist of approved materials that are free of organic matter and debris. Based on the results of our borings, material suitable for re-use as engineered fill may be present at the site provided any deleterious materials, if present, are removed. Off-site

Responsive ■ Resourceful ■ Reliable 5 borrow material should be approved by the geotechnical engineer of record prior to being imported to the site. Samples of each proposed off-site borrow material should be submitted to the geotechnical engineer of record for classification testing. Frozen material should not be used, and fill should not be placed on a frozen subgrade.

Areas where fill is required to develop design grades and areas undercut to remove unsuitable or soft materials should be filled with controlled engineered fill. Fill should be placed and compacted in loose lifts of 9 inches or less and compacted to at least 95% of the material's standard Proctor maximum dry density (KDOT Type AA Compaction). The moisture content of the fill at the time of compaction should be within 3 percentage points of the material’s standard Proctor optimum moisture content (KDOT MR-3-3 Moisture Range).

Where fill is placed on existing slopes steeper than 5H:1V, benches should be cut into the existing slopes prior to fill placement. The benches should have a minimum vertical face height of 1 foot and a maximum vertical face height of 3 feet and should be cut wide enough to accommodate the compaction equipment. This benching will help provide a positive bond between the fill and natural soils and reduce the possibility of failure along the fill/natural soil interface. Furthermore, we recommend that fill slopes be over filled and then cut back to develop an adequately compacted slope face.

Earthwork Construction Considerations

With seasonal water level fluctuations in the Delaware River, it is difficult to predict the near surface groundwater conditions that will be present during construction. The potential for soft subgrade soils during earthwork activities for the project should be anticipated by the contractor.

Accordingly, stabilization of subgrade soils prior to placement of embankment soils should be anticipated and considered when budgeting for the project.

Should unstable subgrade conditions be encountered, the methods described below could be considered to improve subgrade strength. Common methods include scarification, moisture conditioning and recompaction, and removal of unstable materials and replacement with granular fill (with or without geosynthetics). The appropriate method of improvement, if required, depends on factors such as schedule, weather, the size of area to be stabilized, and the nature of the instability.

If the exposed subgrade becomes unstable, methods outlined below can be considered.

◼ Scarification and Recompaction - It may be feasible to scarify, dry, and recompact the exposed soils. The success of this procedure would depend primarily upon favorable weather and sufficient time to dry the soils. Stable subgrades likely would not be achievable if the thickness of the unstable soil is greater than about 1 foot, if the unstable soil is at or near groundwater levels, or if construction is performed during a period of wet or cool weather when drying is difficult.

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◼ Crushed Stone - The use of crushed stone or crushed gravel is the most common procedure to improve subgrade stability. Typical undercut depths would be expected to range from about

6 to 30 inches below finished subgrade elevation. The use of high modulus geotextiles (i.e., engineering fabric or geogrid) could also be considered after underground work such as utility construction is completed. Prior to placing the fabric or geogrid, we recommend that all below grade construction, such as utility line installation, be completed to avoid damaging the fabric or geogrid. Equipment should not be operated above the fabric or geogrid until one full lift of crushed stone fill is placed above it. The maximum particle size of granular material placed over geotextile fabric or geogrid should not exceed 1½ inches.

Further evaluation of the need and recommendations for subgrade stabilization should be provided by a qualified geotechnical engineer during construction as the subgrade conditions are exposed on a broad scale.

Temporary excavations will probably be required during grading operations. The grading contractor, by his contract, is usually responsible for designing and constructing stable, temporary excavations and should shore, slope or bench the sides of the excavations as required, to maintain stability of both the excavation sides and bottom. All excavations should comply with applicable local, state and federal safety regulations, including the current Occupational Safety and Health Administration (OSHA) Excavation and Trench Safety Standards.

Construction Observation and Testing

The earthwork efforts should be monitored under the direction of the Geotechnical Engineer.

Monitoring should include documentation of adequate removal of vegetation and top soil, evaluation of existing fill materials, proof-rolling and mitigation of areas delineated by the proof-roll to require mitigation.

Each lift of compacted fill should be tested, evaluated, and reworked as necessary until approved by the Geotechnical Engineer prior to placement of additional lifts. In areas of shallow foundation excavations, the bearing subgrade should be evaluated under the direction of the Geotechnical

Engineer. In the event unanticipated conditions are encountered, the Geotechnical Engineer should prescribe mitigation options.

In addition to the documentation of the essential parameters necessary for construction, the continuation of the Geotechnical Engineer into the construction phase of the project provides the continuity to maintain the Geotechnical Engineer’s evaluation of subsurface conditions, including assessing variations and associated design changes.

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DEEP FOUNDATIONS

Based on the subsurface conditions encountered at the boring locations, it is our opinion the planned bridge could be supported by deep foundations consisting of driven piles or straight-sided drilled shafts which would derive primary capacity from the shale or limestone bedrock. As previously described, pre-boring for driven piles and rock coring for drilled shafts will likely be required to develop sufficient depth for scour protection and/or lateral capacity.

Recommendations for the design and construction of driven piles and drilled shafts are discussed in the following sections.

Driven Steel Pile Design Parameters

Steel H-piles (HP sections) should be driven through the native soils to achieve bearing in the underlying weathered limestone or shale, using an appropriately sized hammer. The table below provides the upper elevation of bedrock as encountered in the borings and the depth at which we anticipate the piles will achieve the recommended capacity.

Based on Section 10.7.3.2.3 of the AASHTO LRFD Bridge Design Specifications (2012), the nominal resistance of piles driven to point bearing on competent bedrock is controlled by the structural limit state. The nominal compressive resistance of the piles for various limit states should be designed in accordance with Section 6 of the referenced AASHTO specifications.

According to Section 6.5.4.2 of the referenced AASHTO specifications, a structural resistance factor of 0.50 is applicable for H-piles (with pile tips) due to potential damage to the pile while driving through the alluvial materials and into competent bedrock.

Considering the above information, the nominal resistances for HP10x42 and HP12x53 piles composed of steel with a 50 ksi allowable yield stress, driven to refusal in limestone or shale bedrock, and driven with a pile tip, are shown in the following table. If other pile sizes or types will be considered, Terracon should be contacted to provide additional recommendations.

Pile Location Pile Size

Nominal Pile

Resistance 1

(kips)

Factored Pile

Resistance

(kips)

Upper

Elevation 2 of Bedrock

(feet)

Estimated

Tip

Elevation 3, 4

(feet)

West Abutment

Near Boring B-1

HP 10x42 620 310 1004 1001

HP 12x53 775 387.5

East Abutment

Near Boring B-2

HP 10x42 620 310 1006 1001

HP 12x53 775 387.5

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1. These nominal resistance values are applicable if the center-to-center spacing of piles is equal to or greater than 3 times the maximum pile section dimension. If the piles will be spaced closer, a reduction in the design pile capacity would be required based on the geometry of the pile spacing. Terracon should be notified if closer pile spacing is planned.

2. Based on the elevations as shown on the boring logs.

3. All piles should be monitored during driving in order to avoid damage.

4. The quality and strength of the bedrock may vary, and refusal to driving conditions could be encountered at shallower or deeper elevations. Therefore, actual pile lengths may vary. If pre-drilling is required, the values shown above are valid for tip elevations below the elevations shown, provided field observation/PDA testing indicates capacity has been achieved.

We anticipate any uplift forces will be resisted by the weight of the bridge. For driven piles that designed according as recommended in this report, constructed in accordance with KDOT requirements, and observed during construction, we anticipate that the long-term settlement of would be about ½-inch for the Service I Limit State loading, in addition to elastic shortening of the pile materials.

We recommend welding reinforced high strength cast steel tips to the bottom of the H-piles to reduce the potential for pile damage during driving and allow the pile to penetrate into suitable bedrock. We recommend using Associated Pile and Fitting Company (APF) 77600 pile tips, or approved equivalent, such as DFP H-776 or Versabite VB-300P.

Steel piles are subject to corrosion. Selection of a pile section capable of transmitting design loads through the corrosion-reduced section area is a typical method of protection.

Frost action beneath abutments can cause uplift loads on the piles. To avoid potential uplift loads, the base of the abutments should extend a minimum of 3 feet below grade. Requirements of resistance to lateral and uplift loads for the structure were not provided. We estimate that HP piles driven through native soil to refusal in suitable bedrock, or pre-bored into bedrock, would be capable of resisting lateral loads of approximately 5 kips. If piles will be subjected to lateral loads greater than 5 kips, additional analyses, such as LPILE, should be performed to evaluate lateral load capacity. If piles will be subjected to lateral loads greater than 5 kips, additional analyses, such as LPILE, could be performed using the parameters provided in the Drilled Shaft Lateral

Loading section to evaluate lateral load capacity.

Driven Pile Construction Considerations

Driven piles should be installed in accordance with the KDOT Bridge Manual. Pile driving through the upper soils is not expected to be difficult; however, the alluvial soils could contain gravel, cobbles or boulders which result in difficult driving conditions. Furthermore, as described above, penetration into weathered limestone or shale bedrock may occur depending on driving effort and resistance. Therefore, we recommend that point reinforcement and/or flange stiffening be

Responsive ■ Resourceful ■ Reliable 9 considered to protect pile tips from damage during potential hard driving conditions which may occur as the design capacity is being obtained.

Since variations may occur in depth and strength of the bedrock and the strength and composition of the overlying soil layers, piles should be driven until satisfactory driving resistance is developed for the design capacity as evaluated in accordance with an appropriate pile driving formula or by wave equation analysis and verified with a pile driving analyzer.

Care should be taken not to overdrive and damage the piles during installation. Pile installation should be performed by an experienced, knowledgeable contractor who is familiar with the subsurface conditions in the region of the project site. The contractor should be prepared to cut or splice piles, as necessary. Pile installation should be observed by Terracon or other qualified personnel retained to evaluate the installation of the driven piles to assess when adequate bearing has been achieved.

Drilled Shaft Design Parameters

Drilled shafts would derive their capacity from a combination of end bearing and skin friction within the weathered shale or limestone bedrock. We evaluated the nominal tip resistance of drilled shafts based on the design recommendations in the FHWA Drilled Shaft Manual (2010) and the

AASHTO LRFD Bridge Design Specifications (2012). We estimated design strength parameters for the rock based on rock type and our previous experience in similar geologic settings. A geotechnical resistance factor of 0.5 was used for the strength limit state design. The following table summarizes the nominal and factored geotechnical resistance values for drilled shaft design.

Shaft Location

Nominal

Tip

Resistance

(ksf) 1

Factored

Tip

Resistance

(ksf) 1

Nominal

Side

Resistance

(ksf) 2

Factored

Side

Resistance

(ksf) 2

Upper

Elevation of

Bedrock

(feet) 3

Estimated

Tip

Elevation

(feet) 4, 5

West Abutment

Near Boring B-1 60 20 3 1.5 1004 1001

Near Boring B-2 60 20 3 1.5 1006 1001

1. To achieve the listed tip resistance, the drilled shaft should penetration a minimum of 3 ft. into weathered shale or limestone bedrock.

2. The side resistance should be neglected at the bottom of the shaft for a length equal to 1 shaft diameter.

3. The upper elevation of bedrock at the pier and abutment locations were estimated from the nearest boring, actual bedrock elevations at each drilled shaft should be expected to vary.

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4. The drilled shaft estimated tip elevation includes the recommended minimum 3 ft. penetration into moderately weathered bedrock; however if additional shaft length is needed for scour protection and/or lateral capacity, the parameters provided above are valid for elevations below this.

5. Actual bedrock conditions, and the suitability of the bedrock at the design tip elevations, should be evaluated by a Terracon representative during construction of the drilled shafts. We recommend add/deduct unit rate costs be requested for drilled shafts as part of the bidding process.

Drilled shafts should have a minimum diameter of 30 inches to facilitate cleanout of the excavations and evaluation of the bearing materials. For drilled shafts that designed according as recommended in this report, constructed in accordance with KDOT requirements, and observed during construction, settlements of ½ inch or less are expected.

Drilled Shaft Lateral Loading

The following table lists input values for use in LPILE analyses. LPILE will estimate values of kh and E50 based on strength; however, non-default values of kh should be used where provided.

Since deflection or a service limit criterion will most likely control lateral capacity design, no safety/resistance factor is included with the parameters.

Material / Bottom of

Layer Elevation

L-Pile Soil Model Su (psf)

2 (pcf) 2, 3 ε50

K

(pci) qu

(psi)

Existing Fill /

3 ft. from surface

Stiff Clay w/o

Free Water 750 120 Ignore Ignore ---

Soft to Medium Stiff Clays

1005 feet

Stiff Clay w/o

Free Water 750 120 0.015 125 ---

Limestone and Shale Weak Rock 6,000 130 0.004 2,000 250

1. The soil values/elevations are for use at the abutments and are based on the results of Borings B-1 and B-2.

The rock values are for use at the abutments and piers. See Subsurface Profile in Geotechnical

Characterization for more details on Stratigraphy.

2. Definition of Terms:

Su: Undrained shear strength

Moist unit weight ε50: Non default E50 strain

K: Non-default soil modulus – static. Refer to software guidelines for cyclic loading.

qu: Unconfined compressive strength of rock.

3. Buoyant unit weight values should be used below water table.

Lateral deflections of shafts/piles should be evaluated using an appropriate analysis method, and will depend upon the pile’s diameter, length, configuration, stiffness and “fixed head” or “free head” condition. We can provide additional analyses and estimates of lateral deflections for

Responsive ■ Resourceful ■ Reliable 11 specific loading conditions upon request. The lateral load-carrying capacity of drilled shafts may be increased by increasing the shaft diameter and/or length.

Drilled Shaft Construction Considerations

The design capacity of drilled shafts depends on the installation procedures and observations during construction. Drilled shafts should be installed in accordance with the KDOT Bridge Construction

Manual. The drilled shaft construction should be performed by an experienced, knowledgeable contractor who is familiar with the subsurface conditions in the area of the project site.

Temporary steel casing may be required to stabilize the sides of the shaft excavations in the soft overburden soils. Difficult drilling conditions should be expected within the weathered bedrock, and the potential for hard bedrock drilling conditions should also be anticipated. Rock bits or core barrels will likely be required to advance the shaft excavations into the harder shale and limestone bedrock units. Terracon should be retained to perform observation and testing during drilled shaft excavation.

Care should be taken to not disturb the sides and bottom of the excavation during construction.

The bottom of the shaft excavation should be free of loose material before concrete placement. If possible, excess water should be evacuated from the casing to place concrete in the "dry.” If water cannot be pumped from the excavation, then the water level should be allowed to stabilize and then concrete should be placed using the tremie method. Concrete should be placed as soon as possible after the foundation excavation is completed, to reduce potential disturbance of the bearing surface.

If concrete will be placed as the temporary casing is being removed, we recommend the concrete mixture be designed with a slump of about 5 to 7 inches to reduce the potential for arching when removing the casing. Concrete should be directed into the shaft utilizing a centering chute. While withdrawing casing, care should be exercised to maintain concrete inside the casing at a sufficient level to resist earth and hydrostatic pressures acting on the casing exterior. Arching of the concrete, loss of seal and other problems can occur during casing removal and result in contamination of the drilled shaft. These conditions should be considered during the design and construction phases. Placement of loose soil backfill should not be permitted around the casing prior to removal.

Gas could be encountered in the drilled shaft excavations during construction. The contractor should check for gas and/or oxygen deficiency prior to any workers entering the excavation for observation and manual cleanup.

We recommend that a representative of Terracon be present during drilling activities to evaluate the materials removed from the drilled pier excavations to determine when adequate capacity has been developed, to observe the base of the drilled pier to determine that the cuttings have been adequately removed, and also to observe the concreting techniques.

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LATERAL EARTH PRESSURES

Design Parameters

Structures with unbalanced backfill levels on opposite sides should be designed for earth pressures at least equal to values 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 below. 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 and is commonly used for basement walls, loading dock walls, or other walls restrained at the top.

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 Coefficients

Earth Pressure Condition

Coefficient for Backfill Type

Equivalent Fluid

Density (pcf) Surcharge

Pressure, p1 (psf) Earth Pressure, p2 (psf)

Active (Ka)

Granular – 0.3

Lean Clay – 0.42

Lean to Fat Clay – 0.45

(0.3)S

(0.42)S

(0.45)S

(40)H

(50)H

(55)H

At-Rest (Ko)

Granular – 0.47

Lean Clay – 0.59

Lean to Fat Clay – 0.63

(0.47)S

(0.59)S

(0.63)S

(60)H

(70)H

(75)H

Passive (Kp)

Granular – 3.3

Lean Clay – 2.4

Lean to Fat Clay – 2.2

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Applicable conditions to the table above include:

■ 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 pressure to develop, wall must move horizontally to mobilize resistance.

■ Uniform surcharge, where S is surcharge pressure

■ Granular backfill: unit weight = 130 pcf (maximum), and = 32 degrees (minimum)

■ Lean clay soil backfill: unit weight = 120 pcf (maximum), and = 24 degrees (minimum)

■ Lean to fat clay backfill: unit weight = 120 pcf (maximum), and = 22 degrees (minimum)

■ Horizontal backfill, compacted as recommended herein

■ Loading from heavy compaction equipment not included

■ No hydrostatic pressures acting on wall

■ No loading from nearby footings or slabs

■ No dynamic loading

■ No safety factor included in soil parameters

■ Ignore passive pressure in frost zone

Backfill placed against structures should consist of granular soils or low plasticity cohesive soils.

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, 45 and 60 degrees from vertical for the active, at-rest and passive cases, respectively. To calculate the resistance to sliding, a value of 0.32 should be used as the ultimate coefficient of friction between the footing and the underlying soil.

The lateral earth pressure recommendations given in this section are applicable to the design of rigid retaining walls subject to slight rotation, such as cantilever, or gravity type concrete walls.

These recommendations are not applicable to the design of modular block - geogrid reinforced backfill walls (also termed MSE walls). Recommendations covering these types of wall systems are beyond the scope of services for this assignment. However, we would be pleased to develop a proposal for evaluation and design of such wall systems upon request.

Subsurface Drainage for Below-Grade Walls

A perforated rigid plastic drain line installed behind the base of walls and extends below adjacent grade is recommended to prevent hydrostatic loading on the walls. The invert of a drain line around a below-grade building area or exterior retaining wall should be placed near foundation bearing level. The drain line should be sloped to provide positive gravity drainage to daylight or to a sump pit and pump. The drain line should be surrounded by clean, free-draining granular material having less than 5% passing the No. 200 sieve, such as No. 57 aggregate. The free-draining aggregate should be encapsulated in a filter fabric. The granular fill should extend to within 2 feet of final grade, where it should be capped with compacted cohesive fill to reduce infiltration of surface water into the drain system.

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As an alternative to free-draining granular fill, a pre-fabricated drainage structure may be used. A pre-fabricated drainage structure is a plastic drainage core or mesh which is covered with filter fabric to prevent soil intrusion, and is fastened to the wall prior to placing backfill.

GENERAL COMMENTS

Our analysis and opinions are based upon our understanding of the project, the geotechnical conditions in the area, and the data obtained from our site exploration. Natural variations will occur between exploration point locations or due to the modifying effects of construction or weather.

The nature and extent of such variations may not become evident until during or after construction.

Terracon should be retained as the Geotechnical Engineer, where noted in this report, to provide observation and testing services during pertinent construction phases. If variations appear, we can provide further evaluation and supplemental recommendations. If variations are noted in the absence of our observation and testing services on-site, we should be immediately notified so that we can provide evaluation and supplemental recommendations.

Our Scope of Services does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

Our services and any correspondence or collaboration through this system are intended for the sole benefit and exclusive use of our client for specific application to the project discussed and are accomplished in accordance with generally accepted geotechnical engineering practices with no third-party beneficiaries intended. Any third-party access to services or correspondence is solely for information purposes to support the services provided by Terracon to our client.

Reliance upon the services and any work product is limited to our client, and is not intended for third parties. Any use or reliance of the provided information by third parties is done solely at their own risk. No warranties, either express or implied, are intended or made.

Responsive ■ Resourceful ■ Reliable 15

Site characteristics as provided are for design purposes and not to estimate excavation cost. Any use of our report in that regard is done at the sole risk of the excavating cost estimator as there may be variations on the site that are not apparent in the data that could significantly impact excavation cost. Any parties charged with estimating excavation costs should seek their own site characterization for specific purposes to obtain the specific level of detail necessary for costing.

Site safety, cost estimating, excavation support, and dewatering requirements/design are the responsibility of others. If changes in the nature, design, or location of the project are planned, our conclusions and recommendations shall not be considered valid unless we review the changes and either verify or modify our conclusions in writing.

Responsive ■ Resourceful ■ Reliable

ATTACHMENTS

Responsive ■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 1 of 2

EXPLORATION AND TESTING PROCEDURES

Field Exploration

The field exploration program consisted of the following:

Number of Borings Boring Depth (feet) Location

1 33.5 Near west end of existing bridge

1 43 Near east end of existing bridge

1. Below existing ground surface.

2. The boring locations are shown on the attached Exploration Plan

Boring Layout and Elevations: Terracon personnel provided the boring layout using handheld

GPS equipment (estimated horizontal accuracy of about ±10 feet) and referencing existing site features. Approximate ground surface elevations were obtained by interpolation from the provided topographic site plan. If more precise ground surface elevations and/or boring locations are desired, we recommend the borings be surveyed by a professional land surveyor.

Subsurface Exploration Procedures: We advanced the borings with a track-mounted rotary drill rig using continuous flight hollow stem augers and rotary wash boring techniques. Three samples were obtained in the upper 10 feet of each boring and at intervals of 5 feet thereafter. In the thin-walled tube sampling procedure, a thin-walled, seamless steel tube with a sharp cutting edge is pushed hydraulically into the soil to obtain a relatively undisturbed sample. In the split-barrel sampling procedure, a standard 2-inch outer diameter split-barrel sampling spoon is driven into the ground by a 140-pound automatic hammer falling a distance of 30 inches. The number of blows required to advance the sampling spoon the last 12 inches of a normal 18-inch penetration is recorded as the

Standard Penetration Test (SPT) resistance value. The SPT resistance values, also referred to as

N-values, are indicated on the boring logs at the test depths. Rock coring was performed using an

NQ sized core barrel.

We also observed and recorded groundwater levels during drilling and sampling. The groundwater levels are shown on the attached boring log.

Our exploration team prepared field boring logs during drilling operations to record sampling depths, penetration distances, other relevant sampling information, visual classifications of materials encountered during drilling, and our interpretation of subsurface conditions between samples. Final boring logs, prepared from field logs, represent the geotechnical engineer's interpretation, and include modifications based on observations and laboratory tests.

Property Disturbance: We backfilled the boring with auger cuttings and bentonite chips after completion. Our services do not include repair of the site beyond backfilling our borehole. Excess

Responsive ■ Resourceful ■ Reliable EXPLORATION AND TESTING PROCEDURES 2 of 2 auger cuttings and drill fluid were dispersed in the general vicinity of the borehole. Because backfill material often settles below the surface after a period, we recommend the borehole be checked periodically and backfilled, if necessary.

Laboratory Testing

The project engineer reviewed the field data and assigned laboratory tests. The laboratory testing program included the following types of tests:

■ Moisture Content

■ Dry Unit Weight

■ Unconfined Compression

The laboratory testing program included examination of soil samples by an engineer or geologist.

Based on the material’s texture and plasticity, we described and classified the soil samples in accordance with the attached Unified Soil Classification System (USCS).

Rock classification was conducted using locally accepted practices for engineering purposes and was based on drilling characteristics and observation of disturbed samples and auger cuttings;

rock core samples and petrographic analysis may reveal other rock types. Boring log rock classification was determined using the Description of Rock Properties.

Responsive ■ Resourceful ■ Reliable

SITE LOCATION AND EXPLORATION PLANS

Contents:

Site Location Plan

Exploration Plan

Note: All attachments are one page unless noted above.

SITE LOCATION PLAN

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MAP 1 PORTRA IT

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS

EXPLORATION PLAN

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When paragraph markers are turned on you may notice a line of hidden text above and outside the table – please leave that alone. Limit editing to inside the table.

The line at the bottom about the general location is a separate table line. You can edit it as desired, but try to keep to a single line of text to avoid reformatting the page.

MAP 2 LANDSCAPE

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT INTENDED FOR CONSTRUCTION PURPOSES MAP PROVIDED BY MICROSOFT BING MAPS

EXPLORATION RESULTS

Boring Logs (B-1 and B-2)

GeoModel

Rock Core Photo Log

3-3-4 N=7

2-3-3 N=6 2-2-3 N=5

2-1-2 N=3

1-2-2 N=4

2-11-27 N=38

16-35-46 N=81

14.5

23.6

20.5

26.3

36.2

17.8

37.6

16.4

4 INCHES ASPHALT

6 INCHES AGGREGATE

FILL - LEAN TO FAT CLAY, trace silt, sand, and gravel, dark gray trace organics LEAN CLAY (CL), dark gray, soft to medium stiff

SILTY CLAY (CL-ML), dark gray, soft to medium stiff with sand, grayish tan

SHALE, gray, completely weathered

LIMESTONE, (per drillers observations) Auger Refusal at 33.4 Feet

0.3 0.8

9.0

14.0

24.0

33.0 33.4

1027.7+/- 1027.2+/-

1019+/-

1014+/-

1004+/-

995+/- 994.6+/-

(HP)

(HP)

(HP)

(HP)

(HP)

9000+

(HP)

9000+

(HP)

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

IS

B

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L O

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R A

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F t.)

W A

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E L

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F

IE

LD

T

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T R

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U

LT

S

W A

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T E

N T

)LOCATION See Exploration Plan

Latitude: 39.6962° Longitude: -95.6627°

G R

A P

H

IC

L O

G

M O

D E

L

LA

Y E

R

DEPTH

Approximate Surface Elev.: 1028 (Ft.) +/-

ELEVATION (Ft.)

Advancement Method:

Hollow Stem Auger

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 14225103

Drill Rig: ATV

BORING LOG NO. B-1

Kickapoo Tribe in KansasCLIENT:

Horton, KS

Driller: LN

Boring Completed: 02-21-2023

PROJECT: Kickapoo Bridge B104 Replacement

Elevations were estimated from provided plans.

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

130th Street over the Delaware River Horton, KS

SITE:

Boring Started: 02-21-2023

2016 SW 37th St Topeka, KS

WATER LEVEL OBSERVATIONS

No free water observed

R E

C O

V E

R Y

In

S A

M P

LE

N

U M

B E

R

D R

Y U

N

IT

W E

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T pc f)

LA

B

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A T

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Y H

P ps f)

U N

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3-5-7 N=12

3-3-3 N=6 2-3-3 N=6

2-2-2 N=4

1-2-2 N=4

17-38-43 N=81

19-35-46 N=81

RQD = 56%

RQD = 45%

22.2

22.9

27.2

19.1

21.7

26.2

15.3

15.1

3 INCHES ASPHALT

LEAN TO FAT CLAY (CL/CH), trace sand, dark gray with brown, medium stiff to stiff, (Possible Fill) trace gravel

LEAN CLAY (CL), trace silt, grayish tan, medium stiff

SHALE, gray, very severe weathering

LIMESTONE, light gray, slight weathering

SHALE, gray, severe to moderate weathering

LIMESTONE, gray and light gray, moderate weathering SHALE, gray, severe weathering

Boring Terminated at 43 Feet

0.3

12.0

22.0

32.0

33.8

39.0 40.0

43.0

1027.8+/-

1016+/-

1006+/-

996+/-

994.3+/-

989+/- 988+/-

985+/-

RUN 1

RUN 2

RUN 3

(HP)

(HP)

(HP)

9000+

(HP)

(HP)

(HP)

9000+

(HP)

9000+

(HP)

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

T H

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F t.)

ELEVATION (Ft.)

Advancement Method:

Hollow stem auger to 33 feet, NX core to termination.

Abandonment Method:

Boring backfilled with Auger Cuttings and/or Bentonite

Notes:

Project No.: 14225103

Drill Rig: ATV

BORING LOG NO. B-2

Kickapoo Tribe in KansasCLIENT:

Horton, KS

Driller: LN

Boring Completed: 02-20-2023

PROJECT: Kickapoo Bridge B104 Replacement

Elevations were estimated from provided plans.

See Exploration and Testing Procedures for a description of field and laboratory procedures used and additional data (If any).

See Supporting Information for explanation of symbols and abbreviations.

130th Street over the Delaware River Horton, KS

SITE:

Boring Started: 02-20-2023

2016 SW 37th St Topeka, KS

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

F

IE

LD

T

E S

T R

E S

U

LT

S

W A

T E

R C

O N

T E

N T

)LOCATION See Exploration Plan

Latitude: 39.6963° Longitude: -95.6625°

G R

A P

H

IC

L O

G

M O

D E

L

LA

Y E

R

DEPTH

Approximate Surface Elev.: 1028 (Ft.) +/-

WATER LEVEL OBSERVATIONS

No free water observed prior to the introduction of drilling fluids

R E

C O

V E

R Y

In

S A

M P

LE

N

U M

B E

R

D R

Y U

N

IT

W E

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T pc f)

LA

B

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A T

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Y H

P ps f)

U N

C O

N F

IN

E

D C

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P R

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S

IV

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T R

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G T

H ps f)

S A

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T

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1,000

1,005

1,010

1,015

1,020

1,025

1,030

E L

E V

A T

IO

N

M

S L

(f ee t)

Kickapoo Bridge B104 Replacement Horton, KS Terracon Project No. 14225103

Layering shown on this figure has been developed by the geotechnical engineer for purposes of modeling the subsurface conditions as required for the subsequent geotechnical engineering for this project.

Numbers adjacent to soil column indicate depth below ground surface.

NOTES:

B-1 B-2

GEOMODEL

This is not a cross section. This is intended to display the Geotechnical Model only. See individual logs for more detailed conditions.

Lean Clays, varing amounts of silt and sand, soft to medium stiff.3

Limestone and Shale.4

LEGEND

Asphalt

Aggregate Base Course

Fill

Lean Clay

Silty Clay

Shale

Limestone

Lean Clay/Fat Clay

Model Layer General DescriptionLayer Name

Asphalt and Aggregate1

Lean to Fat Clays, varying amounts of silt, sand, gravel, and organics.2

Cohesive Soil

Bedrock

Surface

Fill and Possible Fill Materials

0.83

33.4

0.25 masnapp Line masnapp Callout Approximate elevation of channel

ROCK CORE PHOTO LOG

Photo #1: Boring B-2, Run 1, 33 to 34 feet, Run 2, 34 to 39 feet, Run 3, 39 to 44 feet.

SUPPORTING INFORMATION

General Notes

Unified Soil Classification System

Description of Rock Properties

GENERAL NOTES – DESCRIPTION OF SYMBOLS AND ABBREVIATIONS

GENERAL NOTES

Sampling Water Level Field Tests

Water levels indicated on the soil boring logs are the levels measured in the borehole at the times indicated. Groundwater level variations will occur over time. In low permeability soils, accurate determination of groundwater levels is not possible with short term water level observations.

N Standard Penetration Test Resistance (Blows/Ft.)

(HP) Hand Penetrometer

(T) Torvane

(DCP) Dynamic Cone Penetrometer

UC Unconfined Compressive Strength

(PID) Photo-Ionization Detector

(OVA) Organic Vapor Analyzer

Descriptive Soil Classification

Soil classification is based on the Unified Soil Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand.