CONTRACT CONDITIONS

FOR

UNDERGROUND CHILLED AND HEATING WATER PIPING

UPGRADES

AT

FRISCO CAMPUS

FRISCO, TEXAS

COLLIN COLLEGE

Project Manual

ENGINEER

RWB CONSULTING ENGINEERS

12222 MERIT DRIVE

SUITE 400

DALLAS, TEXAS 75251

RWB Project No. 26015.00

June 15, 2026

6/15/26

COLLIN COLLEGE – FRISCO CAMPUS

UNDERGROUND CHILLED AND HEATING WATER PIPING UPGRADES

26015.00

June 15, 2026 00 01 10 – TABLE OF CONTENTS - 1

SECTION 00 01 10

TABLE OF CONTENTS

DIVISION 00 – PROCUREMENT AND CONTRACTING REQUIREMENTS

00 00 00 COVER

00 01 02 SEALS PAGE

00 01 10 TABLE OF CONTENTS

00 03 00 EXISTING SOILS REPORT

DIVISION 01 – GENERAL REQUIREMENTS

01 01 00 SUMMARY OF WORK

01 02 00 ALLOWANCES

01 02 50 MEASUREMENT AND PAYMENT

01 03 00 ALTERNATES

01 04 00 COORDINATION

01 04 50 CUTTING AND PATCHING

01 05 00 FIELD ENGINEERING

01 06 00 REGULATORY REQUIREMENTS

01 07 00 DEFINITIONS AND TERMINOLOGY

01 12 00 ALTERATION PROJECT PROCEDURES

01 20 00 PROJECT MEETINGS

01 30 00 SUBMITTALS

01 40 00 QUALITY CONTROL

01 50 00 CONSTRUCTION FACILITIES AND TEMPORARY CONTROLS

01 56 39 TREE PROTECTION REMOVAL AND PRUNING

01 60 00 MATERIALS AND EQUIPMENT

01 70 00 CONTRACT CLOSEOUT

01 73 00 OPERATION AND MAINTENANCE DATA

DIVISION 09 – FINISHES

09 90 00 PAINTING

DIVISION 22 – PLUMBING

22 05 00 COMMON WORK RESULTS FOR PLUMBING

22 14 00 STORM DRAINAGE SYSTEM

22 14 29 SUMP PUMPS

June 15, 2026 00 01 10 – TABLE OF CONTENTS - 2

DIVISION 23 – HEATING, VENTILATING, AND AIR CONDITIONING (HVAC)

23 00 00 HEATING, VENTILATING, AND AIR CONDITIONING (HVAC) WORK

23 05 00 COMMON WORK RESULTS FOR HVAC

23 05 53 IDENTIFICATION FOR HVAC DUCTWORK, PIPING, AND EQUIPMENT

23 07 00 INSULATION

23 09 00 CONTROLS AND INSTRUMENTATION

23 21 12 UNDERGROUND HYDRONIC PIPING

23 21 13 HYDRONIC PIPING

23 25 13 HVAC WATER TREATMENT FOR CLOSED-LOOP HYDRONIC SYSTEMS

DIVISION 26 - ELECTRICAL

26 00 00 ELECTRICAL

26 05 19 LOW VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES

26 05 20 CABLE CONNECTIONS

26 05 26 GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS

26 05 32 RACEWAYS

26 05 33 BOXES FOR ELECTRICAL SYSTEMS

26 05 53 IDENTIFICATION FOR ELECTRICAL SYSTEMS

26 27 26 WIRING DEVICES

26 28 16 ENCLOSED SWITCHES AND CIRCUIT BREAKERS

DIVISION 31 – EARTHWORK

31 10 00 SITE CLEARNING

31 22 00 GRADING

31 22 19 FINISH GRADING

DIVISION 32 – EXTERIOR IMRPOVEMENTS

32 01 30 LANDSCAPE MAINTENANCE FOR ONE YEAR

32 13 00 RIGID PAVING

32 13 14 CONCRETE PAVING – ARCHITECTURAL FINISHES AND JOINTS

32 14 13 PRECAST CONCRETE UNIT PAVING

32 17 23 PAVEMENT MARKINGS

32 84 00 LANDSCAPE IRRIGATION SYSTEM

32 92 00 TURF AND GRASSES

32 93 00 LANDSCAPING

DIVISION 33 – SITE UTILITIES

33 40 00 STORM DRAINAGE UTILITIES

33 41 14 LANDSCAPE DRAINAGE SYSTEM

June 15, 2026 00 07 00 –EXISTING SOILS REPORT - 1

SECTION 00 03 00

EXISTING SOILS REPORT

The following soils report was provided by Collin College for the Health Science Center being built on the same campus and provides overall guidance and direction on the general types of soils and conditions that exist at the site.

END OF SECTION

Geotechnical Evaluation Report

Proposed Health Science Building Collin College Preston Ridge Campus Frisco, Texas

Prepared for

Collin College

Douglas P. Ziolkowski, P.E.

Senior Engineer License Number: 57574 August 26, 2024

Project B2405687

Braun Intertec Corporation TBPELS Registration No. F-12228

AA/EOE

Braun Intertec Corporation 1160 Mustang Drive, Ste. 300 Dallas, TX 75261

Phone: 817.786.5999 Web: braunintertec.com

Send USPS mail to: P.O. Box 1685 Grapevine, TX 76099

August 26, 2024 Project B2405687

Mr. Chris Eyle Collin College 3452 Spur 399, Suite 310 McKinney, Texas 75069

Re: Geotechnical Evaluation Report Proposed Health Science Building Collin College Preston Ridge Campus Frisco, Texas

Dear Mr. Eyle:

Braun Intertec Corporation is pleased to present this Geotechnical Evaluation Report for the proposed Health Science Center Building planned on the Collin College Preston Ridge Campus located in the south -central portion of Frisco, Texas. The attached report contains a description of our review of available information, our field exploration program, our engineering evaluation, and interpretation of the results concerning the geotechnical site development, foundation design as well as construction guidelines for the planned project.

Thank you for making Braun Intertec Corporation your geotechnical consultant for this project. If you have questions about this report or if there are other services that we can provide in support of our work to date, please contact us.

Sincerely, BRAUN INTERTEC CORPORATION

TBPELS Firm Registration No. F-12228

Douglas P. Ziolkowski. P.E.

Senior Engineer

Randy Deatherage, P.E.

Senior Manager | Senior Engineer

Table of Contents

Description Page

A. Introduction

A.1. Project Description A.2. Site Conditions and History A.3. Purpose A.4. Background Information and Reference Documents A.5. Scope of Services

B. Results B.1. Geologic Overview B.2. Subsurface Conditions B.3. Depth to Rock B.4. Free Water B.5. Laboratory Test Results

C. Recommendations C.1. Design and Construction Discussion

C.1.a. Expansive Soil Conditions C.1.b. Foundation-Type Structure Support and Floor Slab Types C.1.c. Reuse of On-Site Soils C.1.d. Groundwater C.1.e. Weather

C.2. Site Grading and Subgrade Preparation C.2.a. Site Grading C.2.b. Excavated Slopes C.2.c. Excavation Dewatering C.2.d. Excavated Surface C.2.e. Building and Pavement Subgrade Proof Roll C.2.f. Fill Materials and Compaction C.2.g. Inspections of Soils C.2.h. Moisture Density Relations Testing C.2.i. Mixing of Fill Lifts and Benching C.2.j. Rock Fragments C.2.k. Blasting and Excavation

C.3. Straight Drilled Shafts C.3.a. Design Parameters for Drilled Shaft Foundations C.3.b. Group Effects for Axial Loads C.3.c. Drilled Shaft Support C.3.d. Adhesion Uplift C.3.e. Lateral Loading Considerations C.3.f. Grade Beams and Pier Caps C.3.g. Drilled Shaft Construction Considerations C.3.h. Special Inspections of Drilled Shafts

C.4. Suspended Slab C.4.a. Suspended Slabs Constructed over a Crawl Space C.4.b. Suspended Slab Constructed on Void Forms

C.5. Floor Slab-on-Grade C.5.a. Slab-on-Grade Subgrade Preparation Discussion

Table of Contents (continued)

C.5.b. Slab-on-Grade Subgrade Modification- Method 2 C.5.c. General Discussion C.5.d. Excavation Observations

C.6. Additional Floor Slab Considerations C.6.a. Membrane under Slab C.6.b. Utilities through Slab C.6.c. Utilities below Suspended Slab

C.7. Design Parameters for Lightly Loaded Structures C.8. Lateral Earth Pressures

C.8.a. Drainage C.8.b. Selection, Placement, and Compaction of Wall Back Fill C.8.c. Configuring and Resisting Lateral Loads

C.9. Pavements C.9.a. Design Sections C.9.b. Concrete Pavements C.9.c. Performance and Maintenance

C.10. Flatwork C.11. Drainage Considerations

C.11.a. Below Grade Areas C.12. Landscaping and Trees C.13. Seismic Site Classification C.14. Equipment Support

D. Procedures D.1. Test Borings D.2. Exploration Logs

D.2.a. Log of Boring Sheets D.2.b. Geologic Origins

D.3. Material Classification and Testing D.3.a. Visual and Manual Classification D.3.b. Laboratory Testing

D.4. Groundwater Measurements E. Qualifications

E.1. Variations in Subsurface Conditions E.1.a. Material Strata E.1.b. Groundwater Level

E.2. Continuity of Professional Responsibility E.2.a. Plan Review E.2.b. Construction Observations and Testing

E.3. Use of Report E.4. Standard of Care

Appendix A- Site Figures Figure 1- Site Vicinity Map Figure 2- Site Topographical Map Figure 3- Site Geologic Map Figure 4- Boring Location Plan with Layout

Table of Contents (continued)

Appendix B – Test Boring Logs Log of Borings: Sheets B-01 through B-09

Appendix C – Test Results Table C.1- Summary of Free Swell Test Results Unconfined Compression Test Results (2 sheets)

A. Introduction

A.1. Project Description

We understand the project will include the design and construction of a new Health Science Center

Building for Collin College. The new building is planned at the Collin College Preston Ridge Campus in south-central Frisco, Texas as shown on the Site Vicinity Map included as Figure 1 within Appendix A. It is our understanding that the building will be a 3 to 4 story, concrete-framed structure with floor plates of approximately 30,000 square feet. Total square footage for the building will be between 90,000 to

120,000 square feet. A mechanical penthouse may be constructed on the building roof. Some small new surface parking areas and drives will be required to support the new building. The Boring Location Plan included as Figure 4 in Appendix A depicts the building layout as provided to Braun Intertec. The following tables provide additional project details.

Table 1. Building Description

Aspect Description

Below grade levels None

Above grade levels 3 to 4 Stories

Finished floor elevation (FFE) 759.5 feet MSL per RLK Engineering

Column loads (kips) 150 to 1,050 kips per IMEG

Floor Slab Load (psf) 100 to 125 psf assumed

Nature of construction Cast in place concrete construction supported on drilled shafts with floor slab either structurally supported or constructed on modified subgrade

Cuts or fills for building Fills of up to 3½ feet and cuts of up to ½ foot to achieve finished subgrade elevation of 759.0 feet MSL

Tolerable foundation movement ¾ -inch total per IMEG

Collin College Proposed Health Science Center August 26, 2024

Table 2. Additional Site Features

Aspect Description

Pavement type Concrete Pavement for cars, light trucks, fire vehicles and occasional large trucks and trash collecting vehicles.

Grade changes Cuts of up to up to 1 foot and fill placement of up to 4 feet estimated from information provided by RLK Engineering

Retaining Walls None

A.2. Site Conditions and History

The proposed Health Science Building will be located on the Collin College Preston Ridge Campus which is located at the northwest corner of Wade Boulevard and Ohio Drive in the south-central portion of Frisco, Texas. The new Health Science Center Building will be constructed within the northeast portion of the school campus on a currently unused section of the campus as shown on Figure 1- Site Vicinity Map included within Appendix A. The area of the new building is surrounded by the IT Center of Excellence building to the west, concrete paved parking lot to the north, concrete paved fire lane and drive to the south and additional vacant land and campus drives to the east.

The site of the proposed building is open land covered by native grasses, weeds, and bare soil, sand and rock fragment covered areas. The boring location plan provided as Figure 4 within Appendix A depicts the current site as it appeared at the time of drilling our test borings. There is a drainage swale and collection area for storm drainage at the northwest corner of the open area where the new building is planned. The collection area is lined by stone rip rap and there is headwall that drains into a box culvert that traverses to the north under the adjacent north parking lot.

Based on the Site Topographical Map (refer to Figure 3 in Appendix A), the site slopes downward from the southeast to the northwest. From information provided by RLK Engineering, the site elevations range from near Elevation 761 feet MSL (Mean Sea Level) near the southeast corner of the open land area down to approximately Elevation 749 feet MSL at the northwest corner within the stormwater collection area, providing approximately 12 feet of relief across the entire site. Within the proposed building area, the site surface elevations vary from approximately Elevation 759.5 feet at the east end down to approximately Elevation 755.5 feet at the northwest corner, providing approximately 4 feet of gentle relief across the building area. According to information provided to us, the new Health Science Building will have a Finished Floor Elevation (FFE) of Elevation 759.5 feet MSL. It appears that fill placement of approximately 3½ feet and soil excavation (cut) of up to ½ foot will be required to achieve finished subgrade elevation within the building. Based on the existing grades, it is estimated that cuts of up to 1 foot and fill placement of up to 4 feet will be required to achieve near subgrade elevation within the proposed parking lot and drive areas around the new building.

A.3. Purpose

The purpose of our geotechnical evaluation is to provide geotechnical recommendations for the design and construction of the proposed new Health Science Cener Building. In support of this effort, we characterized the subsurface geologic conditions at selected exploration locations and evaluated their impact on the proposed project. We performed our services in accordance with generally accepted engineering practices prevailing at the time and in the geographical area of the project location.

A.4. Background Information and Reference Documents

We reviewed the following information:

Historical aerial images (ranging from 1995 to 2023) of the project site using Google Earth™.

Site Vicinity and Site Topographical Maps from USGS Topoview program, Hebron Quadrangle, dated 2022 (used for Figures 1 and 2 in Appendix A.)

Site Geology Map- Geologic Atlas of Texas; Sherman Sheet, Revised 1987- Refer to Figure 3 in Appendix A.

Boring Location Plan with Site Layout by PBK Architects – Used for Figure 4 in Appendix A.

We have described our understanding of the proposed construction and site to the extent others reported it to us. Depending on the extent of available information, we may have made assumptions based on our experience with similar projects. If we have not correctly recorded or interpreted the project details, the project team should notify us. New or changed information such as a revised finished floor elevation could require additional evaluation, analyses, and/or revised recommendations.

A.5. Scope of Services

We performed our scope of services for the project in accordance with our proposal to Mr. Chris Eyle with Collin College as described within QTB197629REV2 dated June 12, 2024. The work was subsequently authorized by receipt of Collin College Purchase Order No. 127187 dated June 13, 2023.

The following list describes the geotechnical tasks completed in accordance with our authorized scope of services:

Reviewed the background information and reference documents previously cited.

Coordinated the staking and clearing of the exploration locations for checking the locations for underground utilities. We selected and staked the exploration locations for nine (9) test borings. The Boring Location Plan- Figure 4 included in Appendix A shows the approximate locations of the completed borings.

Performed nine test borings. Borings (B--01 through B-09) were drilled in the proposed Health Science Building area to depths of 30 to 35 feet below ground.

Performed laboratory testing on selected samples to aid in soil classification and engineering analysis.

Discussed the site conditions we anticipate will impact structure design and performance, qualified the nature of their impact, and outlined alternatives for mitigating their impact.

Discussed the reuse of on-site materials during construction and the potential impact of groundwater on construction.

Provided recommendations for preparing structure subgrades including the selection, placement, and compaction of excavation backfill and other structural fill. We also estimated potential soil heave. The report includes our recommendations for subgrade modification to reduce the potential soil heave below slab on grade floor to a design criteria of ¾ inch or less as requested by the project structural engineer.

Provided deep foundation design parameters for straight-sided drilled shafts.

Provided recommendations for light, medium and heavy-duty pavements.

Provided recommendations for design of below grade walls including active, passive and at-rest pressures for various backfill types.

Our scope of services did not include environmental services or testing, and the persons performing this evaluation were not trained to provide environmental services or testing. We can provide these services or testing at your request.

B. Results

B.1. Geologic Overview

The site is situated within the Austin Chalk geologic formation (refer to Kau on Figure 3- Site Geologic Map within Appendix A). This formation is typically composed of residual fat and lean clay soils that are weathered from the underlying chalk, marl, and limestone formation. Soils developed on the Austin Chalk Formation are typically composed of highly plastic fat clays and less plastic lean clays with weathered rock seams. The plastic soils observed exhibit expansive characteristics. The soils transition into tan, weathered tan rock, which generally becomes less weathered and denser with depth, and extends to unweathered rock, which at this site is gray in color. Some of the observed material at this site is considered an intermediate geomaterial (IGM) with strength characteristics between soil and rock and with some characteristics of a marl soil and other characteristics of limestone or marlstone. The IGM readily breaks into soil with manipulation of construction equipment and sufficient water, including milling machines, bulldozers, and sheepsfoot compactors. The intact, unweathered rock materials are relatively strong and can support significant loads.

The geology maps used as part of this study typically did not include ground verification of the boundaries between geologic formations even though the maps were originally developed by others using aerial photography. As a result, the mapped boundaries should be considered approximate. The soils, IGM, and rock observed at the site are generally consistent with the anticipated geology. We note that apparent fill and possible fill materials were observed beginning at the ground surface within eight of the nine test borings. It should be anticipated that other areas of the new building area will encounter fill materials of unknown depth. The fill materials were likely placed during past grading and construction of the adjacent campus buildings to the west and south.

B.2. Subsurface Conditions

Table 3 below provides a subsoil strata summary of the material observed in the borings performed at the site. Please refer to the Logs of Borings sheets provided in Appendix B for additional details. Within Appendix B following the boring logs, we have also provided descriptive terminology sheets for soils and rock that include definitions of abbreviations used in Table 3.

Table 3: Subsoil Strata Summary

B.3. Depth to Rock Tan weathered rock (limestone) was observed at depths ranging from 8 to 17 feet below the existing grade within the nine test borings. Gray unweathered rock (limestone) was observed at depths ranging from 8 to 17 feet below the existing grade within the nine test borings. We note that a false layer of unweathered rock was encountered at a depth from 9 to 12 feet within test boring B-2. Table 4 summarizes the depth to weathered and unweathered rock in each boring location.

Strata Soil Type -

ASTM

Classification

Relative Density/

Consistency

Approximate Depth to

Bottom of Stratum

Commentary and Details

Fill, Possible Fill and

Natural Fat Clay and Lean

Clay

CH, CL

1.0 to 4.5+ tsf

8 to 77 bpf

5 – 12½ feet

Dark brown to brown to tan Medium to hard in consistency Contains varying amounts of calcareous nodules and weathered limestone fragments and seams.

Fill and possible fill material encountered in eight of the nine borings to depths of 2 to 4 feet.

Weathered

Rock (Limestone)

SPT-

50/3”

TCP-

100/2” to 88/10”

8 to 17 feet

Tan to tan and gray Limestone is slightly to moderately weathered with occasional thin lean clay seams

Layer of gray unweathered limestone encountered above the tan weathered limestone from 9 to 12 feet in boring B-02.

Unweathered

Rock (Limestone)

TCP-

100/0.25” to 100/3”

Termination Gray Extends to beyond 30-35 feet depth in borings B-01 through B-09

Table 4. Rock Depth Summary

*Denotes false layer of gray rock was encountered from 9 to 12 feet within test boring B-2.

B.4. Free Water

During drilling, no free water was observed within any of the nine test borings. At completion of the individual test borings, all nine borings were found to be dry prior to backfilling. A groundwater study was not included in our scope of work. Details regarding the observed free water levels are included in the Logs of Boring included in Appendix B.

It is difficult to accurately predict the magnitude of subsurface water fluctuations that may occur following periods of inclement weather. Free water can be present above any of the less permeable soils or rock and can flow through fissures and sandier soils, creating a temporary perched water condition, particularly during wetter seasons. Therefore, water levels should be expected to fluctuate throughout the year with variations in weather, precipitation runoff, irrigation, site topography, utilities, and water levels from nearby surface water features and other factors that are unknown or not evident at the time of this study.

Boring ID Approximate Depth to

Tan Weathered Rock (ft)

Approximate Depth to Gray

Unweathered Rock (ft)

B-01 12½ 16

B-02 12* 17

B-03 7½ 12

B-04 8 14

B-05 7 13

B-06 7 10

B-07 5 8

B-08 11½ 12½

B-09 9 13

Long-term observations would be required to provide an accurate evaluation of the water levels and their fluctuations. If these services are desired, Braun Intertec would be pleased to provide water level monitoring as an additional scope of services.

B.5. Laboratory Test Results

Laboratory testing was performed on selected samples recovered from the borings to confirm visual classification and estimate the pertinent engineering properties of the observed soils. The following paragraphs summarize the selected data. Atterberg limit tests, moisture content tests, and percent passing the No. 200 sieve tests were performed on selected soil samples. The individual test results can also be found on the Logs of Boring sheets provided within Appendix B.

The measured in-situ moisture content of the soils ranged from approximately 6 to 41 percent. Liquid limits of the tested samples ranged from 42 to 90 with corresponding plasticity indices varying from 29 to 60, which indicates a moderate to very high soil plasticity. A high plasticity index is generally associated with a high potential for active clay soils to shrink and swell in response to changes in the soil moisture content.

In addition to the index testing outlined above, four one-dimensional swell tests were performed. The test results ranged from 0.4 to 5.9 percent swell for each test and are presented on Table C.1 in Appendix C. The free swell test result indicates a low to high risk of heave at the time of our field exploration activities.

We also performed two unconfined strength tests (ASTM D2166) on selected samples of the upper clay soil strata. The test results varied from 1.1 to 2.4 tsf and are presented on the boring logs provided in Appendix B. The test results are also presented in graphic form within Appendix C.

C. Recommendations

C.1. Design and Construction Discussion

The following conclusions and recommendations are based on our site observations, our interpretation of the field and laboratory data obtained during this exploration, our discussions with the project team, and our experience with similar subsurface conditions. Soil and rock penetration data, and rock compressive strengths were considered in developing our estimate of allowable bearing pressures.

When developing these estimates, we also considered previous correlations of penetration data and allowable foundation bearing pressures. Subsurface conditions in unexplored locations may vary from those observed in the borings. If anything changed from the above understanding such as building finished floor elevations, Braun Intertec must be advised so that we may reevaluate and possibly revise our recommendations. If these characteristics or the layout of the proposed project changes, we should be contacted to review the changes and provide further recommendations as needed.

C.1.a. Expansive Soil Conditions The current site stratigraphy beneath the proposed Health Science Center building consists of fat to lean clays extending to depths ranging from approximately 5 to 12½ feet below the existing grade. These soils typically provide sufficient support when maintained in a moist condition. However, our analysis showed that the native clay subgrade soils have expansive properties and will tend to shrink and swell in response to changes in moisture. These shrinking and swelling movements can cause the unsatisfactory performance of the foundation and slab-on-grade systems and reducing the magnitude of these movements, through either mitigation and/or moisture control, will be paramount to the success of structures bearing on them.

The potential for soil heave was estimated using the Texas Department of Transportation Potential Vertical Rise (PVR) method (Test Procedure TEX-124-E) and free swell test results. The PVR value from a dry to wet state obtained at the existing grade and heave estimates based on the swell test results were estimated to vary from 2 inches up to 4 inches. The surficial soils observed in the borings for the proposed building are considered to have high to very highly expansive properties.

Depending on the magnitude of grading performed beneath the building to establish the final grade, the magnitude of potential heave may either exceed or be less than the estimated values presented above.

The potential for increases in the total soil-related movement becomes more likely if fat clay soils obtained on-site are placed in a dry or nearly dry condition beneath areas covered by slab, flatwork, or pavement. The estimated shrink/swell movements are based on the soil moisture variations from a dry to a wet condition. The actual soil movements that will occur depending on various factors. The soil movements could be less than the calculated PVR if the moisture remains fairly consistent. However, extreme moisture fluctuations resulting from extended droughts, flooding, shallow groundwater, poor site drainage, and/or leaking irrigation lines may result in shrinking or swelling values in excess of the calculated PVR.

C.1.b. Foundation-Type Structure Support and Floor Slab Types

Braun Intertec was not provided a site grading plan; however, we did receive a site topographic drawing from RLK Engineering. Based on the provided finished floor elevation described in Table 1 (FFE of 759.5 feet MSL) the building will require approximately 3½ feet of fill and cuts of up to ½ foot to achieve the proposed finished subgrade elevation at 6 inches below the finished floor elevation.

The project structural engineer has requested that the maximum soil related movement below slabs-on-grade below the building structure be ¾-inch or less. Based on the subgrade modifications that will be required to reduce the soil potential vertical movement, it is our opinion that a ¾- inch movement cannot be achieved for this project site for slab-on-grade systems. We feel that with the subgrade recommendations provided in Section C.5 of this report, that a 1-inch design movement can be obtained. If this movement potential is not acceptable to the client and design team, then a structural slab system as discussed in Section C.4 will need to be utilized.

As indicated in Section C.1.a, the estimated potential heave beneath the new Health Science Building was estimated to be within 2 to 4 inches. During our evaluation, we considered several soil modification methods for the site slab on grade as well as the use of a structural slab system. The soil modification methods included:

Method 1 - Remove a specific depth of the surficial, high-plasticity, clay soils and replace with imported select fill;

Method 2 - Remove a specified depth of the surficial, high-plasticity, clay soils, moisture condition the soils and place the moisture-conditioned materials back into the excavation to a specified depth and complete the balance with imported select fill or flexible base to achieve the desired final grade;

Method 3 - Electrochemically pressure inject and in-situ stabilize the surficial clays and install a surface layer of special fill or flexible base; or, Utilize some combination of the above three methods.

The select fill referenced in Methods 1 and 2 consists of low plasticity silty clay, sandy clay, or clayey sand soils with a plasticity index between 7 and 18. Historically, these soils were normally imported from borrow pits located near existing or former river and/or stream channels, however, presently, these soils are often manufactured and imported to the project site. Select fill materials do not naturally occur in the Austin Chalk Formation and therefore would not be expected on this site. Select fill materials will need to be imported from an approved off-site source.

Braun Intertec recommends using Method 2, as described above, for subgrade modification beneath slab-on-grade floor system for the new Health Science building. Method 1 (undercut and replace with select fill) is anticipated to be very costly as it will require 8-10 feet of select fill to be placed to reduce the potential vertical movements to within the specified range. Settlement of select fill soils may additionally be a concern. Method 3 is also not considered practical for the site based on the variable depth to weathered limestone and the presence of weathered limestone seams at relatively shallow depths. Our specific recommendations utilizing Method 2 are provided in detail within Section C.5 of this report.

Foundations We recommend using straight-sided, drilled shafts socketed into gray, unweathered rock (limestone) to support the new building and to resist uplift pressures from the expansive clays. Our recommendations for drilled shaft foundation systems are presented in Section C.3 of this report.

Small lightly-loaded signs and dumpster areas which are not considered movement-sensitive may be supported on shallow mats or stiffened or post-tensioned slab foundations provided the subgrade has been modified below the foundations. Recommendations for shallow foundation systems are discussed within Section C.7.

Structural Floor Slab or Slab-on-Grade The two most common floor slab systems associated with a pier and grade beam foundation consist of either a suspended structural floor slab system or ground supported floor slab constructed over a modified subgrade. A suspended floor slab structurally connects the floor slab and grade beams directly beneath the floor slab to the drilled shafts and provides separation of the floor slab from the underlying expansive soils by either a formed void system or a crawl space. A suspended floor slab system is not in contact with the underlying expansive clays, therefore, virtually eliminating the effects of post-construction slab movement due to the swelling and shrinking of the underlying soils.

Recommendations for a suspended floor slab system are provided within Section C.4 of the report.

Slab-on-Grade Floor System

An alternative to structurally suspended floor slabs is to support the floor slab system directly on a modified subgrade. When installing a floor slab on a modified subgrade in expansive clays, the owner must accept the risk of soil-related movement beneath the slab. Subgrade modifications must be performed beneath any floor slab areas supported on-grade to reduce the swell potential of properly installed clay fill soils beneath the proposed building. General discussion regarding proposed subgrade modification below the building is provided above. Additional recommendations for subgrade modifications beneath the slab-on-grade system for the new building are provided in Section C.5.

The subgrade recommendations have been prepared to reflect the current site grades known to us and as referenced within this report. If designed and constructed properly, the subgrade modification methods we recommend beneath the new building are intended to reduce the total Potential Vertical Rise to 1 inch or less. The estimated differential movement should be limited to 50 percent or less of the total vertical movement. The resulting soil-related movements are dependent on strict implementation of our recommendations for grading, backfill, and drainage. If our recommendations are not followed, then the risk that greater than predicted movements and the associated distress will be experienced increases significantly.

C.1.c. Reuse of On-Site Soils The near-surface, on-site soils will not meet the requirements for select fill as defined in Section C.2. Any soils that are considered for use as select fill must be imported from an approved off-site source and must be tested to ensure compliance with the material specifications. On-site soils can also be used as grade raise fill beneath building and new pavement areas provided they are processed and installed per the requirements for common fill soils as described in Section C.2 and C.5. We do not recommend reusing existing fill that contains debris or organic material as common fill or moisture-conditioned fill.

C.1.d. Groundwater No free water seepage was observed within any of the nine test borings. During the proposed subgrade modifications, and due to the sloping nature of the site, it should be anticipated that subsurface water may temporarily impact earthwork operations, and if so, the water should be collected in low areas and sump pumps used to remove the water. Also, during construction, and based on our experience on the PRC Campus, free water should be anticipated during the installation of a few randomly located drilled shafts. Some of the soils will collect water from precipitation or surface runoff. We recommend the contractor remove any water that collects in work areas before performing further work. Groundwater conditions may be different at the time of construction. Groundwater conditions typically vary because of seasonal variations in rainfall, landscape irrigation, site drainage, and runoff. Groundwater can also be present within fractures in the weathered and unweathered rock.

C.1.e. Weather To account for potential rainfall during construction, we recommend maintaining construction grades to intercept surface water flow into the area and drain water from the areas to an appropriate collection point. After grading, the contractor should compact the soil surface with a smooth drum roller in an effort to lower infiltration rates. After rain events, the contractor should limit construction traffic until the surface is dry enough that traffic will not mix accumulated surface water into the soil.

C.2. Site Grading and Subgrade Preparation

C.2.a. Site Grading Before proceeding with construction, all vegetation, root systems, and other deleterious, non-soil materials must be stripped from proposed construction areas. Organic material must not comprise more than 5 percent of the soil matrix used as structural fill.

Proper subgrade preparation and placement and construction of the grade raise fill materials will be very critical to the performance of building foundations, floor slabs, and new pavements constructed above or near these soft wet areas and elsewhere on-site. Care should be exercised during the grading operations at the site. The traffic of heavy equipment, including heavy compaction equipment, may create a general deterioration of the shallower, clayey soils. Therefore, it should be anticipated that some construction difficulties could be observed during periods when these soils are saturated and that it may be necessary to improve, remove or simply stay off of the saturated soils.

C.2.b. Excavated Slopes Based on the borings, we anticipate on-site soils and rock in excavations will consist of fat clay, lean clay, and weathered limestone. Table 5 provides OSHA (Occupational Safety and Health Administration) guidelines in reference to soil type.

Table 5. Maximum Allowable Excavation Side Slopes

Slopes constructed in this manner may still exhibit surface sloughing. OSHA requires an engineer to evaluate slopes or excavations over 20 feet in depth. An OSHA-approved qualified person should review the soil classification in the field. Excavations must comply with the requirements of OSHA 29 CFR, Part 1926, Subpart P, “Excavations and Trenches.” This document states excavation safety is the responsibility of the contractor. The project specifications should reference these OSHA requirements.

C.2.c. Excavation Dewatering As previously described, no free water was observed within any of the nine test borings. However, due to the sloping nature of the site and the seasons in which construction takes place, free water may be

Soil Classification Soil Type Slopes (H:V)

Fat and lean Clay or weathered rock Type B 1:1

Fat and lean Clay or weathered rock (with seepage) Type C 1 ½:1 encountered. Therefore, we recommend removing any accumulation of free water that may develop within the excavations using sumps areas to collect the water and remove the water with pumps.

C.2.d. Excavated Surface The bottom of the subgrade excavation for the building may encounter a mix of soils and weathered/unweathered rock. While competent rock does not always require excavation, it is important that where rock is encountered within the building footprint during subgrade modification, that it be ripped and removed and that the full depth of subgrade modification recommended in Section C.5 be obtained before placing moisture-conditioned fill back into the excavation.

C.2.e. Building and Pavement Subgrade Proof Roll After excavating the building pad and other areas to the depths indicated within Section C.5 and before the placement of moisture-conditioned fill, we recommend proof rolling the subgrade soils per TxDOT Item 216 provided the exposed materials are not intact rock. We also recommend having a geotechnical representative observe the proof roll. Areas that fail the proof roll likely indicate soft or weak areas that will require additional soil correction work to support building foundations and slabs as well as pavements.

The contractor should correct areas that display yielding or rutting. Possible options for subgrade correction include moisture conditioning (ripping and drying or wetting) and re-compaction, excavation (undercutting) and replacement with re-compacted soil or crushed aggregate, chemical stabilization, and/or geotextiles. We recommend performing a second proof roll after the aggregate flexible base material is in place, and before constructing the foundations or pavements.

C.2.f. Fill Materials and Compaction Table 6 contains our recommendations for fill materials. Please note that we have not received any detailed information regarding below grade walls for this site and have provided portions of our recommendations for completeness.

Table 6. Fill Materials*

Locations to Be Used

Fill Classification

Possible Soil Type

Descriptions Gradation Additional Requirements

Below Foundations, floor slabs, utilities

Select fill SC, CL

1. 100% passing 3-inch sieve

2. 60% maximum passing

No. 200 sieve

1. Liquid Limit <35

2. Plasticity Index between 7 and 18

3. < 2% Organic Content (OC)

Moisture Conditioned Soil and Rock

CH, CL,

weathered rock

3. 100% passing 3-inch sieve 4. < 2% Organic Content (OC)

Flexible Base -- Meet the Requirements of TxDOT Item 247, Grade 1-2, Type A or D

Below Pavement and Retaining Walls

General Site Fill

CH, CL,

weathered and unweathered rock

100% passing 3-inch sieve

< 2% Organic Content (OC)

Behind retaining walls

Granular Backfill

GW, GP

5% maximum passing No. 200 sieve

30% maximum passing No. 40 sieve

Granular backfill such as ASTM C-33, No. 57 or 467 with appropriate filter media protection

Below landscaped surfaces, where settlement is not a concern

Non-structural fill

On-site soils 100% passing 4-inch sieve < 5% OC

*Abbreviations are defined in the attached Descriptive Terminology sheets.

All coarse aggregates behind retaining walls should be completely encased in a nonwoven geotextile, such as Mirafi 160N or equal, to prevent the migration of silts and clays into the free-draining backfill. A geotextile layer may be omitted if concrete sand (ASTM C-33 Fine Aggregate) is used.

All fill soils should be installed in loose lifts approximately eight inches thick. We recommend compacting fill per the criteria presented below in Table 7. The project documents should specify the relative compaction of fill, based on the structure located above the fill, and vertical proximity to that structure.

Table 7. Compaction Recommendations Summary

Reference Recommended Compaction, percent

(ASTM D698 – Standard Proctor) Moisture Content Variance from

Optimum, percentage points Select fill soils 97 plus -2 to +3

Moisture conditioned native soils 92 to 96

96 to 98 (upper 6 inches) +5 to +8

+2 to +4 (upper 6 inches) Common fill, below structures, pavements, and utilities

95 to 100 0 to +4

Flexible base 95 plus

Top Lift 100+ -2 to +3

Non-select fill, below landscaped surfaces

93 to 96 ±4

We recommend performing density tests in the fill to evaluate if the contractors are effectively compacting the soil and meeting project requirements. Table 8 contains our recommended frequency of testing for various aspects of the project.

Table 8. Fill Testing Frequency

Zone Designation Fill Testing Frequency Minimum Tests per Soil Lift

Building Pad 1 test per every 5,000 square feet 2

Pavement Areas 1 test per every 2,500 square feet 2

Utility Lines 1 test every 150 linear feet 1 Test per every 1 foot of fill

Grade Beams 1 test every 100-150 linear feet 1 Test per every 6” compacted lift

Manholes –City of Frisco ROW Spiral tests 1 Test per every 2 feet of Fill

C.2.g. Inspections of Soils The purpose of soil inspections is to evaluate whether the work is per the recommendations contained in the Geotechnical Evaluation Report for the project. Inspections should include evaluation of the subgrade, observing the preparation of the subgrade (surface compaction or dewatering, excavation oversizing, placement procedures and materials used for fill, etc.), and compaction testing of the fill.

C.2.h. Moisture Density Relations Testing Moisture density relations testing (field densities) should be performed on each lift by the Geotechnical Engineer or his/her qualified representative to document that the proper moisture content and compaction requirements have been achieved. If the compacted materials fail to meet the moisture and density requirements, the lift should be reprocessed as necessary to obtain the required results.

C.2.i. Mixing of Fill Lifts and Benching All fill materials should be placed in level, uniform lifts with each lift properly moisture treated and compacted as recommended above. Each lift should be thoroughly mixed to help insure the uniformity of the layer.

C.2.j. Rock Fragments Excavated rock materials or rock fragments to be placed as fill, should be completely broken down, distributed as widely as practical across the site, and placed with no nested voids. Placing soil clods or rock fragments larger than a three-inch diameter increases the risk of nested voids and may lead to an unexpected localized settlement that will likely damage site improvements. Rock fragments larger than three inches in size should be removed from the excavation.

C.2.k. Blasting and Excavation Due to the presence of weathered and unweathered limestone observed in the test borings, field operations such as grading, utility excavations, and straight shaft excavations may encounter difficult excavation conditions, especially upon initial penetration into the rock layers. Therefore, the contractor should be prepared to handle these difficulties with special rock removal equipment and rock drilling equipment. Blasting should not be considered for this project site due to the relative softness of the rock observed within the test borings.

C.3. Straight Drilled Shafts

C.3.a. Design Parameters for Drilled Shaft Foundations The bearing stratum at this site is gray, unweathered rock (limestone) which was observed at approximately 8 to 17 feet depth below the existing grade within the area of the proposed new Health Science Center building. We recommend the straight, drilled shafts be designed to have at least two feet of penetration into the intact, gray rock (or below any temporary casing, whichever is deeper) to achieve the allowable end bearing and skin friction values. We also recommend allowable skin friction only be considered for that portion of the shaft embedded more than two feet in the intact, gray rock and below any temporary casing, if required. However, variations in the rock surface should be anticipated. The final depth of penetration will be determined by a representative of the geotechnical engineer in the field. We recommend that drilled shafts be a minimum of 18 inches in diameter for shafts less than 30 feet in length. Due to the difficulty in observing and confirming the cleanliness of the shaft excavations prior to concrete placement, we recommend that the minimum shaft diameter be at least 24 inches for piers extending below a depth of 30 feet. Table 9 below contains our recommended design parameters for the straight, drilled shafts.

Table 9. Recommended Drilled Shaft Design Parameters

Bearing Stratum Approximate Depth Range*

Allowable End Bearing Resistance

Allowable Skin Friction -

Compression Allowable Skin

Friction – Tension

Gray Rock (Limestone)

8 to 17 feet 70,000 psf 10,500 psf 8,400 psf

Note: *See individual boring logs for depth to rock below existing grade.

Settlement of a properly constructed drilled shaft founded in unweathered gray rock (limestone) is expected to occur as the drilled shaft is loaded. Total and differential settlements are estimated to be less than 1/4-inch.

C.3.b. Group Effects for Axial Loads To develop allowable bearing resistance given in Table 9, we recommend that adjacent shafts maintain a minimum center-to-center spacing of three times the diameter of the larger shaft. Pier groups closer than three diameters (center-to-center) should be reduced from full capacity at three diameters to 50 percent capacity at 2 diameters. Linear interpolation can be applied to pier groups closer than three diameters should also bear at the same elevation. The total capacity of the shafts in the group should also be checked against block type failure mode (See FHWA-NHI-10-016 14-2 and 14-3 for further discussion). If piers will be closer than two diameters, we should review the configuration to determine appropriate reduction factors. The same load reductions should apply when deep utility trenches are within 1 ½ pier diameters of an individual pier.

Groups of three or more shafts, or groups of shafts with uplift loads, should be evaluated on a case-by-case basis by this office. Alternative installation sequences should be implemented during group shaft installation to allow for a minimum of 48 hours of curing time for concreted shafts, before installation of adjacent shafts.

C.3.c. Drilled Shaft Support We anticipate that a few, random drilled shafts may require casing to prevent the infiltration of groundwater and maintain the integrity of the shaft excavation.

C.3.d. Adhesion Uplift Consideration should be given to potential uplift generated through soil-to-shaft adhesion of expansive clay soils within the active zone. Although these conditions may vary with location and soil conditions at the time of placement, it may be assumed for design purposes that the active zone extends approximately eleven feet below the final ground surface regardless of shaft location. Additionally, the average adhesive stress acting upward on the exterior surface (perimeter) of the drilled shaft throughout this zone may be assumed to be approximately 1,500 psf. If the soils are moisture-conditioned and capped with select fill per Section C.5, this value can be reduced to 750 psf acting over the top 11 feet of the shaft regardless of the location. Care must be taken to prevent desiccation of the soils. If the area will be left open for greater than 48 hours, the moisture-conditioned soils should be protected with a select fill cap of at least 3 feet in thickness. Uplift resistance for wind loads will be provided by side friction developed within the rock and the deadweight of the drilled shaft element.

C.3.e. Lateral Loading Considerations Our recommended lateral load design parameters for use in the L-Pile computer program are provided in Tables 10 and 11. Table 10 presents design values for the soil and weathered limestone materials observed in the upper 0 to 8-17 feet below existing ground surface. Table 11 presents design values for the gray unweathered limestone rock. Due to possible soil shrinkage, the upper five feet should not be considered for lateral loading conditions in shaft design.

Table 10. Recommended L-Pile Soil Design Parameters

Stratum Soil Type

Depth Range

(ft.) p-y Model

Effective Unit

Weight (pcf)

Undrained Shear

Strength (ksf)

Strain Factor ε50

Friction Angle

(degrees) ks value

(pci)

Natural Fat Clay (CH)

0-5 Neglect 125 Neglect Neglect Neglect Neglect

1 and 2

Fat Clay, Lean Clay

(CH/CL)

and weathered Limestone

5 to 8-

Stiff clay w/out free water 115 3 0.005 0 1,000

Table 11. Recommended L-Pile Rock Design Parameters

Stratum Type Depth Range

(ft)

Unit Weight

(pcf)

Uniaxial Compressive

Strength (psi)

Young’s Modulus, Er (psi)

Rock Quality

Designation, RQD, (%)

Strain Factor, krm

Unweathered Limestone – Weak Rock

(Reese)

Below 8-17 140 2,500 100,000 70 0.0004

The program models the shaft behavior using a finite difference method and determines the non-linear response of the soil using various soil resistance-pile deflection (p-y) criteria. The program accommodates the analysis of various shaft types subjected to axial load, lateral load, and bending moments. Braun Intertec recommends the designers size the drilled shafts and select appropriate reinforcing steel to resist the anticipated forces.

C.3.f. Grade Beams and Pier Caps The cross-section of the pier shafts should not be allowed to increase (mushroom) at or near the ground surface during the installation of the piers.