COLE HIGH SCHOOL BAND HALL -...

COLE HIGH SCHOOL BAND HALL

Ft. Sam Houston Independent School District

Ft. Sam Houston San Antonio, TX

PROJECT MANUAL

VOLUME 1

Stantec Project No. 214000210

ISSUED FOR BIDDING & CONSTRUCTION

November 17, 2014

Board of Trustees Deborah E. Seabron President COL Randall Anderson Vice President Dr. Eustace Lewis Secretary Jeanne Warren Member Jane Crow Member

Superintendent

Dr. Gail Siller

ARCHITECT

New Band Hall Stantec Project No. 214000210 Cole High School November 6, 2014 Ft. Sam Houston ISD Issued For: Competitive Sealed Proposals

VOLUME 1 DIVISION 00 GENERAL REQUIREMENTS 00 01 01 TITLE PAGE INSTRUCTIONS TO OFFERORS GEO-TECHNICAL REPORT DIVISION 01 GENERAL CONDITIONS 00 01 01 TABLE OF CONTENTS 00 01 15 DRAWING SHEET INDEX 01 21 00 ALLOWANCES 01 25 00 SUBSTITUTION PROCEDURES 01 26 00 CONTRACT MODIFICATION PROCEDURES 01 31 00 PROJECT MANAGEMENT AND COORDINATION 01 31 19 PROJECT MEETINGS 01 33 00 SUBMITTAL PROCEDURES 11-6-14 01 40 00 QUALITY REQUIREMENTS 01 42 00 REFERENCES 01 43 39 MOCK-UP SUBMITTALS (ROOFING) 01 50 00 TEMPORARY FACILITIES AND CONTROLS 01 57 23 TEMPORARY STORMWATER 01 60 00 PRODUCT REQUIREMENTS 01 73 00 EXECUTION 01 73 29 CUTTING AND PATCHING 01 77 00 CLOSEOUT PROCEDURES 01 78 00 WARRANTIES AND BONDS 07 78 23 OPERATION AND MAINTENANCE DATA 01 78 39 PROJECT RECORD DOCUMENTS 01 79 00 DEMONSTRATION AND TRAINING DIVISION 02 EXISTING CONDITIONS 02 41 19 SELECTIVE DEMOLITION DIVISION 03 CONCRETE 03 11 13 VOID FORMS 03 11 19 INSULATED CONCRETE FORMS 03 15 13 EXP. CONTR. JOINTS AND WATERSTOPS 03 20 00 CONCRETE REINFORCING 03 20 01 CONCRETE REINFORCMENT - CIVIL 03 30 00 CAST IN PLACE CONCRETE - STRUCTURAL 03 30 00.13 COLD WEATHER CONCRETING 03 30 00.16 HOT WEATHER CONCRETING 03 30 01 CAST IN PLACE CONCRETE - CIVIL 03 35 13 POLISHED CONCRETE 03 40 00 PLANT PRECAST CONCRETE BELOW GRADE 03 62 00 NON-SHRINK GROUT DIVISION 04 MASONRY 04 05 23 THROUGH WALL FLASHING 04 20 00 UNIT MASONRY ASSEMBLIES 04 43 13 ANCHORED STONE MASONRY VENEER DIVISION 05 METALS 05 12 00 STRUCTURAL STEEL 05 21 00 STEEL JOISTS AND JOISTS GIRDER 05 31 13 STEEL FLOOR DECKING 05 31 23 STEEL ROOF DECKING 05 40 00 COLD-FORMED METAL FRAMING 05 50 00 METAL FABRICATIONS 05 52 13 PIPE AND TUBE RAILINGS

TABLE OF CONTENTS OF THE CONSTRUCTION DOCUMENTS - PROJECT MANUAL 000110 - PAGE 1 OF 4 2014 SHW GROUP ARCHITECTS | ENGINEERS | PLANNERS


DIVISION 06 WOOD, PLASTICS AND COMPOSITES 06 10 00 ROUGH CARPENTRY 06 20 23 INTERIOR FINISH CARPENTRY 06 40 23 INTERIOR ARCHITECTURAL WOODWORK DIVISION 07 THERMAL AND MOISTURE PROTECTION 07 19 00 WATER REPELLENTS 07 21 00 THERMAL INSULATION 07 22 16 ROOF AND DECK INSULATION 07 27 26 FLUID APPLIED MEMBRANE AIR BARRIER 07 41 23 METAL WALL PANELS AND SOFFIT PANELS 07 52 16 MODIFIED ASPHAL BITUMINOUS ROOFING 07 61 13 STANDING SEAM 07 62 00 SHEET METAL 07 62 13 GUTTERS AND DOWNSPOUTS 07 72 00 ROOF ACCESSORIES 07 81 00 SPRAYED FIRE-RESISTIVE MATERIALS 07 81 36 THROUGH-PENETRATION FIRESTOP SYSTEMS 07 84 46 FIRE RESISTIVE JOINT SYSTEMS 07 92 00 JOINT SEALANTS 07 95 00 EXPANSION CONTROL DIVISION 08 OPENINGS 08 03 85 STEEL ACOUSTICAL DOOR ASSEMBLIES 08 11 13 HOLLOW METAL DOOR AND FRAMES 08 14 16 FLUSH WOOD DOORS 08 31 13 ACCESS DOORS AND FRAMES 04 41 00 ACOUSTICAL WINDOW ASSEMBLY 08 41 13 ALUMINUM ENTRANCES AND STOREFRONTS 08 71 00 FINISH HARDWARE 08 80 00 GLAZING DIVISION 09 FINISHES 09 21 16 GYPSUM BOARD ASSEMBLIES 09 28 00 GYPSUM SHEATHING 09 30 13 CERAMIC TILE 09 51 13 ACOUSTICAL PANEL CEILINGS 09 54 38 WOOD GRILLE CEILING 09 65 13 RESILIENT WALL BASE AND ACCESSORIES 09 65 19 RESILIENT FLOOR TILE 09 77 23 ACOUSTICAL WALL PANELS 09 91 13 PAINTING DIVISION 10 SPECIALTIES 10 11 00 VISUAL DISPLAY UNITS 10 14 00 SIGNAGE 10 21 13 TOILET COMPARTMENTS 10 28 00 TOILET AND BATH ACCESSORIES 10 44 00 FIRE PROTECTION SPECIALTIES DIVISION 11 EQUIPMENT NOT USED DIVISION 12 FURNISHINGS 12 21 13 HORIZONTAL LOUVER BLINDS DIVISION 13 SPECIAL CONSTRUCTION NOT USED



DIVISION 14 CONVEYING EQUIPMENT NOT USED DIVISION 20 MECHANICAL NOT USED VOLUME 2 DIVISION 21 FIRE PROTECTION 21 05 00 COMMON WORK RESULTS FOR FIRE SUPPRESSION 21 13 13 WET PIPE SPRINKLER SYSTEMS DIVISION 22 - PLUMBING 22 05 00 COMMON WORK RESULTS FOR PLUMBING 22 05 23 GENERAL DUTY VALVES FOR PLUMBING PIPING 22 05 29 HANGERS SUPPORTS FOR PLUMBING PIPING AND EQUIPMENT 22 05 53 IDENTIFICATION FOR PLUMBING PIPING AND EQUIPMENT 22 07 00 PLUMBING INSULATION 22 11 00 FACILITY WATER DISTRIBUTION 22 13 00 FACILITY SANITARY SEWERAGE 22 14 00 FACILITY STORM DRAINAGE 22 14 29 SUMP PUMPS 22 33 00 ELECTRIC DOMESTIC WATER HEATERS 22 40 00 PLUMBING FIXTURES DIVISION 23 HEATING, VENTILATING AND AIR CONDITIONING (HVAC) 23 05 00 GENERAL MECHANICAL REQUIREMENTS 23 05 03 PIPES AND TUBES FOR HVAC PIPING AND EQUIPMENT 23 05 13 COMMON MOTOR REQUIREMENTS FOR HVAC EQUIPMENT 23 05 29 HANGERS AND SUPPORT FOR HVAC PIPING AND EQUIPMENT 23 05 48 VIBRATION AND SEISMIC CONTROLS FOR HVAC PIPING AND EQUIPMENT 23 05 53 IDENTIFICATION FOR HVAC PIPING AND EQUIPMENT 23 05 93 TESTING, ADJUSTING AND BALANCING FOR HVAC 23 07 00 HVAC INSULATION 23 09 00 DIRECT DIGITAL CONTROL SYSTEM FOR HVAC 23 23 00 REFRIGERANT PIPING 23 31 00 HVAC DUCTS AND CASINGS 23 33 00 AIR DUCT ACCESSORIES 23 34 00 HVAC FANS 23 37 00 AIR OUTLETS AND INLETS 23 81 26 DUCTLESS MINI-SPLIT SYSTEM AIR CONDITIONERS 23 81 28 VARIABLE REFRIGERANT FLOW SYSTEMS DIVISION 26 ELECTRICAL 26 05 00 ELECTRICAL REQUIREMENTS 26 05 19 LOW VOLTAGE ELECTRICAL POWER CONDUCTORS AND CABLES 26 05 26 GROUNDING AND BONDING FOR ELECTRICAL SYSTEMS 26 05 29 HANGERS AND SUPPORTS FOR ELECTRICAL SYSTEMS 26 05 33 RACEWAY AND BOXES FOR ELECTRICAL SYSTEMS 26 05 53 IDENTIFICATION FOR ELECTRICAL SYSTEMS 26 22 00 LOW VOLTAGE TRANSFORMERS 26 24 16 PANEL BOARDS 26 27 26 WIRING DEVICES 26 28 13 FUSES 26 51 00 INTERIOR LIGHTING 26 52 00 EMERGENCY LIGHTING 26 56 00 SITE LIGHTING DIVISION 27 LOW VOLTAGE / TECHNOLOGY 27 10 00 STRUCTURED CABLING SYSTEM 27 13 00 COMMUNICATIONS COAXIAL CABLING



27 41 00 AUDIO VISUAL SYSTEMS DIVISION 28 ELECTRONIC SAFETY AND SECURITY 28 31 76 INTERIOR FIRE ALARM AND MASS NOTIFICATION SYSTEM DIVISION 31 EARTHWORK 31 00 00 EARTHWORK 31 10 00 SITE CLEARING AND GRUBBING 31 23 00 EXCAVATION AND FILL 31 23 23 FLOWABLE FILL 31 32 11 EROSION AND SEDIMENT CONTROL 31 50 00 EXCAVATION SUPPORT AND PROTECTION 31 63 29 DRILLED PIERS DIVISION 32 EXTERIOR IMPROVEMENTS 32 11 24 GRADED CRUSHED AGGREGATE BASE 32 11 30 LIME TREATED SUBGRADE 32 12 10 HMAC TACK AND PRIME COATS 32 12 17 HMAC PAVEMENT 32 13 13 CONCRETE PAVEMENT 32 16 13 CURBS AND SIDEWALKS 32 17 23 PAVEMENT MARKINGS DIVISION 33 - UTLITIES 33 11 00 WATER DISTRIBUTION 33 33 00 SANITARY SEWERS 33 40 00 STORM DRAINAGE 33 46 00 SUBDRAINAGE SYSTEM END OF SECTION 000110



DOCUMENT 00 01 01 - PROJECT TITLE PAGE

PROJECT MANUAL

NEW BAND HALL COLE HIGH SCHOOL Ft. Sam Houston Independent School District 4005 Winans Rd. Ft. Sam Houston San Antonio, TX 78234 Phone: (210) 368-8700 Fax: (210) 368-8741

Architect Project No. 214000210

Stantec 1344 SOUTH FLORES, SUITE 201 SAN ANTONIO, TEXAS 78204 P 210.223.9588 F 210.223.9589 Web Site: www.stantec.com

ISSUED FOR BIDDING AND CONSTRUCTION

Issued: November 17, 2014

Copyright 2014 Stantec. All rights reserved.

END OF DOCUMENT 00 01 01

PROJECT TITLE PAGE 000101 - 1

http://www.stantec.com/

GEOTECHNICAL ENGINEERING STUDY

FOR

FT SAM HOUSTON ISD BAND HALL AND MUSIC BUILDING

SAN ANTONIO, TEXAS

GEOTECHNICAL ENGINEERING STUDY

For

FT SAM HOUSTON ISD BAND HALL AND MUSIC BUILDING

SAN ANTONIO, TEXAS

Prepared for

FT SAM HOUSTON INDEPENDENT SCHOOL DISTRICT San Antonio, Texas

Prepared by

RABA KISTNER CONSULTANTS, INC. San Antonio, Texas

PROJECT NO. ASA14-066-00

September 15, 2014

Project No. ASA14-066-00 September 15, 2014

TABLE OF CONTENTS

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INTRODUCTION ....................................................................................................................................... 1

PROJECT DESCRIPTION ............................................................................................................................ 1 LIMITATIONS ........................................................................................................................................... 1 BORINGS AND LABORATORY TESTS ......................................................................................................... 2 GENERAL SITE CONDITIONS ..................................................................................................................... 2

SITE DESCRIPTION ......................................................................................................................................... 2 GEOLOGY ....................................................................................................................................................... 3 SEISMIC CONSIDERATIONS ........................................................................................................................... 3 STRATIGRAPHY .............................................................................................................................................. 4 GROUNDWATER ............................................................................................................................................ 4

FOUNDATION ANALYSIS .......................................................................................................................... 5 EXPANSIVE SOIL-RELATED MOVEMENTS ..................................................................................................... 5 OVEREXCAVATION AND SELECT FILL REPLACEMENT .................................................................................. 5

Drainage Considerations ........................................................................................................................ 6

FOUNDATION RECOMMENDATIONS ....................................................................................................... 7

FOUNDATION OPTIONS ................................................................................................................................ 7 SITE GRADING ................................................................................................................................................ 7 AREA FLATWORK ........................................................................................................................................... 8 DRILLED-AND-UNDERREAMED PIERS ........................................................................................................... 8

Pier Shaft Potential Uplift Forces ........................................................................................................... 9 Allowable Uplift Resistance .................................................................................................................... 9

PIER SPACING ................................................................................................................................................ 9 SUSPENDED FLOOR SLAB ............................................................................................................................ 10

ENGINEERED BEAM AND SLAB FOUNDATION ........................................................................................... 10 Allowable Bearing Capacity .................................................................................................................. 10

FOUNDATION CONSTRUCTION CONSIDERATIONS ................................................................................. 11 SITE DRAINAGE ............................................................................................................................................ 11 SITE PREPARATION ...................................................................................................................................... 11

SELECT FILL .................................................................................................................................................. 12 LIME TREATMENT OF SOILS ........................................................................................................................ 12 SHALLOW FOUNDATION EXCAVATIONS .................................................................................................... 13 DRILLED PIERS .............................................................................................................................................. 13

Reinforcement and Concrete Placement ............................................................................................ 13 Temporary Casing ................................................................................................................................. 14


TABLE OF CONTENTS

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EXCAVATION SLOPING AND BENCHING ..................................................................................................... 14 EXCAVATION EQUIPMENT .......................................................................................................................... 14

CRAWL SPACE CONSIDERATIONS ............................................................................................................... 14 Ventilation ............................................................................................................................................ 14 Below Slab Utilities ............................................................................................................................... 15 Drainage ................................................................................................................................................ 15 Carton Forms ........................................................................................................................................ 15

UTILITIES ...................................................................................................................................................... 16

PAVEMENT RECOMMENDATIONS ......................................................................................................... 16 SUBGRADE CONDITIONS ............................................................................................................................. 17 DESIGN INFORMATION ............................................................................................................................... 17 FLEXIBLE PAVEMENT ................................................................................................................................... 17

Garbage Dumpsters .............................................................................................................................. 18

RIGID PAVEMENT ........................................................................................................................................ 18

PAVEMENT CONSTRUCTION CONSIDERATIONS ..................................................................................... 19 SUBGRADE PREPARATION .......................................................................................................................... 19 DRAINAGE CONSIDERATIONS ..................................................................................................................... 19 ON-SITE CLAY FILL ........................................................................................................................................ 20

GEOGRID REINFORCEMENT ........................................................................................................................ 20 FLEXIBLE BASE COURSE ............................................................................................................................... 21 ASPHALTIC CONCRETE SURFACE COURSE .................................................................................................. 21 PORTLAND CEMENT CONCRETE ................................................................................................................. 21

CONSTRUCTION RELATED SERVICES ...................................................................................................... 21

CONSTRUCTION MATERIALS TESTING AND OBSERVATION SERVICES ...................................................... 21 BUDGETING FOR CONSTRUCTION TESTING ............................................................................................... 22

ATTACHMENTS

The following figures are attached and complete this report: Boring Location Map .......................................................................................................................... Figure 1 Logs of Borings .......................................................................................................................... Figures 2 to 3 Key to Terms and Symbols ................................................................................................................. Figure 4 Results of Soil Analyses ...................................................................................................................... Figure 5 Important Information About Your Geotechnical Engineering Report


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INTRODUCTION RABA KISTNER Consultants Inc. (RKCI) has completed the authorized subsurface exploration and foundation analysis for the proposed band hall and music building for the Ft Sam Houston ISD located at the existing school campus on Ft Sam Houston in San Antonio, Texas, as illustrated on Figure 1. This report briefly describes the procedures utilized during this study and presents our findings along with our recommendations for foundation design and construction considerations, as well as for pavement design and construction guidelines.

PROJECT DESCRIPTION The facilities being considered in this study include a new band hall and music building located at the existing school campus on Ft Sam Houston in San Antonio. It is our understanding that at the time of this study, site grading plans and proposed structural loads were not yet available. The proposed single-story building is anticipated to create relatively light loads which will be carried by the foundation system. Also included in the report will be general guidelines for construction of parking and drive pavements for the project.

LIMITATIONS This engineering report has been prepared in accordance with accepted Geotechnical Engineering practices in the region of south/central Texas and for the use of the Ft Sam Houston Independent School District (CLIENT) and its representatives for design purposes. This report may not contain sufficient information for purposes of other parties or other uses. This report is not intended for use in determining construction means and methods. The attachments and report text should not be used separately. The recommendations submitted in this report are based on the data obtained from two borings drilled at this site, our understanding of the project information provided to us, and the assumption that site grading will result in only minor changes in the existing topography. If the project information described in this report is incorrect, is altered, or if new information is available, we should be retained to review and modify our recommendations. This report may not reflect the actual variations of the subsurface conditions across the site. This is particularly true of this site with respect to the depth of the upper surficial fill materials. The nature and extent of variations across the site may not become evident until construction commences. The construction process itself may also alter subsurface conditions. If variations appear evident at the time of construction, it may be necessary to reevaluate our recommendations after performing on-site observations and tests to establish the engineering impact of the variations. The scope of our Geotechnical Engineering Study does not include an environmental assessment of the air, soil, rock, or water conditions either on or adjacent to the site. No environmental opinions are presented in this report.


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If final grade elevations are significantly different from existing grades (more than plus or minus 1 ft), our office should be informed about these changes. If needed and/or if desired, we will reexamine our analyses and make supplemental recommendations.

BORINGS AND LABORATORY TESTS Subsurface conditions at the site were evaluated by 2 borings drilled at the locations shown on the Boring Location Map, Figure 1. These locations are approximate and distances were measured using a hand-held, recreational-grade GPS locator; tape; angles; pacing; etc. The borings were drilled to depths of approximately 40 ft below the existing ground surface using a truck-mounted drilling rig. During drilling operations, 22 Split-Spoon samples (with Standard Penetration Tests) were collected. Each sample was visually classified in the laboratory by a member of our geotechnical engineering staff. The geotechnical engineering properties of the strata were evaluated by the following tests:

Type of Test Number Conducted

Natural Moisture Content 22

Atterberg Limits 5

Percent Passing a No. 200 Sieve 4

The results of all laboratory tests are presented in graphical or numerical form on the boring logs illustrated on Figures 2 through 3. A key to classification terms and symbols used on the logs is presented on Figure 4. The results of the laboratory and field testing are also tabulated on Figure 5 for ease of reference. Standard Penetration Test results are noted as blows per ft on the boring logs and Figure 5, where blows per ft refers to the number of blows by a falling hammer required for 1 ft of penetration into the soil/weak rock (N-value). Where hard or dense materials were encountered, the tests were terminated at 50 blows even if one foot of penetration had not been achieved. When all 50 blows fall within the first 6 in. (seating blows), refusal ref for 6 in. or less will be noted on the boring logs and on Figure 5. Samples will be retained in our laboratory for 30 days after submittal of this report. Other arrangements may be provided at the request of the Client.

GENERAL SITE CONDITIONS SITE DESCRIPTION The project site is a tract of partially developed land located at the existing school campus on Ft Sam Houston in San Antonio. This site visually appeared to have been used as a staging area for various projects performed at the school in the past. An existing school building is located immediately to the south of the proposed music and band hall building. The topography generally slopes downward toward


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the north with vertical relief of about 5 ft across the site. Surface drainage is visually estimated to range from poor to fair. Although not encountered in the 2 borings drilled as a part of this study the presence of buried structures in the existing fill at this site (old foundations, pavements, brick, debris, abandoned utilities, etc.) are possible and should be anticipated during construction. GEOLOGY A review of the Geologic Atlas of Texas, San Antonio Sheet, indicates that this site is naturally underlain by fluviatile terrace deposits which are stream bed deposits typically consisting of clays, sands, silts, and gravels. Such deposits can contain point bars, cutbanks, oxbows, and abandoned channel segments associated with variations in stream bed activity. As a result, soil profiles in terrace deposit areas may vary greatly over relatively short distances. Key geotechnical engineering concerns for development supported on this formation are the expansive nature of the clays, the consistency or relative density of the deposits, and the absence/presence as well as thickness of potentially water-bearing gravels. SEISMIC CONSIDERATIONS Based upon a review of Section 1613 Earthquake Loads Site Ground Motion of the 2012 International Building Code, the following information has been summarized for seismic considerations associated with this site.

Site Class Definition (Chapter 20 of ASCE 7): Class C. Based on the soil borings conducted for this investigation, the upper 100 feet of soil may be characterized as very dense soil and soft rock.

Risk-Targeted Maximum Considered Earthquake Ground Motion Response Accelerations for the Conterminous United States of 0.2-Second Spectral Response Acceleration (5% Of Critical Damping) (Figure 1613.3.1(1)): Ss = 0.080g. Note that the value taken from Figure 1613.3.1(1) is based on Site Class B and is adjusted per 1613.3.3.

Risk-Targeted Maximum Considered Earthquake Ground Motion Response Accelerations for the Conterminous United States of 1-Second Spectral Response Acceleration (5% Of Critical Damping) (Figure 1613.3.1(2)): S1 = 0.031g. Note that the value taken from Figure 1613.3.1(2) is based on Site Class B and is adjusted per 1613.3.3.

Values of Site Coefficient (Table 1613.3.3(1)): Fa = 1.2 Values of Site Coefficient (Table 1613.3.3(2)): Fv = 1.7 Where g is the acceleration due to gravity.

The Maximum Considered Earthquake Spectral Response Accelerations are as follows:

0.2 sec, adjusted based on equation 16-37: Sms = 0.096g 1 sec, adjusted based on equation 16-38: Sm1 = 0.052g


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The Design Spectral Response Acceleration Parameters are as follows:

0.2 sec, based on equation 16-39: SDS = 0.064g 1 sec, based on equation 16-40: SD1 = 0.035g

Based on the parameters listed above, Tables 1613.3.5(1) and 1613.3.5(2), and calculations performed using the United States Geological Survey (USGS) website, the Seismic Design Category for both short period and 1 second response accelerations is A. As part of the assumptions required to complete the calculations, a Risk Category of IV was selected. STRATIGRAPHY The subsurface stratigraphy at this site can be described by four generalized strata. Each stratum has been designated by grouping soils that possess similar physical and engineering characteristics. The boring logs should be consulted for more specific stratigraphic information. The lines designating the interfaces between strata on the boring logs represent approximate boundaries. Transitions between strata may be gradual. Stratum I is fill generally consisting of medium dense to dense, dark brown, clayey gravel with chert. A portion of these samples that passed a No. 40 sieve are classified as plastic to highly plastic with measured plasticity indices ranging from 37 to 44. Measured moisture contents range from 7 to 15 percent. Standard Penetration Test (SPT) N-values range from 24 to 45 blows per ft. Based on grain size analyses, the percentage of fines (percent passing a No. 200 sieve) ranges from 18 to 52 percent. This stratum extends to depths ranging from 6 to 8 ft below the existing ground surface in our borings. Stratum II consists of stiff to very stiff, dark brown clay. These clays are classified as highly plastic with a single measured plasticity index of 47. Measured moisture contents range from 21 to 25 percent. SPT N-values range from 11 to 18 blows per ft. This stratum extends to a depth of approximately 13 ft below the existing ground surface in Boring B-1. This stratum was not encountered in Boring B-2. Stratum III consists of very stiff to hard, tan and gray clay. These clays are classified as highly plastic with measured plasticity indices ranging from 44 to 51. Measured moisture contents range from 18 to 22 percent. SPT N-values range from 29 to 50 blows per ft. This stratum extends to depths ranging from 24 to 28 ft below the existing ground surface in our borings. Stratum IV consists of hard, gray clayshale. Measured moisture contents range from 9 to 18 percent. SPT N-values range from 50 blows for 6 in. of penetration to refusal for 1 in. of penetration. This stratum extends to at least the termination depth in our borings. GROUNDWATER Upon completion of the drilling operations, groundwater levels were measured in Boring B-2 to be approximately 13 ft below the existing ground surface. Based on observations noted by our drill crew during drilling operations, groundwater seepage was first observed at a depth of approximately 8 ft in Boring B-2. We expect that this water is not associated with permanent water table in this area but


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instead is localized perched water, located at the base of the fill material encountered at this site. Based on these observations we estimate that subsurface water could be encountered at depths as shallow as about 8 ft below the existing ground surface. Boring B-1 remained dry during the field exploration phase. Fluctuations in groundwater levels are possible due to variations in rainfall and surface water run-off. The construction process itself may also cause variations in the groundwater levels.

FOUNDATION ANALYSIS EXPANSIVE SOIL-RELATED MOVEMENTS The anticipated ground movements due to swelling of the underlying soils at the site were estimated for slab-on-grade construction using the empirical procedure, Texas Department of Transportation (TxDOT) Tex-124-E, Method for Determining the Potential Vertical Rise (PVR). PVR values ranging from 4 to 4-3/4 in. were estimated for the stratigraphic conditions encountered in our borings. A surcharge load of 1 psi (concrete slab and sand layer), an active zone of 15 ft, and dry moisture conditions were assumed in estimating the above PVR values. The TxDOT method of estimating expansive soil-related movements is based on empirical correlations utilizing the measured plasticity indices and assuming typical seasonal fluctuations in moisture content. If desired, other methods of estimating expansive soil-related movements are available, such as estimations based on swell tests and/or soil-suction analyses. However, the performance of these tests and the detailed analysis of expansive soil-related movements were beyond the scope of the current study. It should also be noted that actual movements can exceed the calculated PVR values due to isolated changes in moisture content (such as due to leaks, landscape watering....) or if water seeps into the soils to greater depths than the assumed active zone depth due to deep trenching or excavations. OVEREXCAVATION AND SELECT FILL REPLACEMENT To reduce expansive soil-related movements in at-grade construction, a portion of the upper highly expansive subgrade clays in the building area could be removed by overexcavating and backfilling with a suitable select fill material. The surficial fill is gravelly in nature and does not contribute as significantly to the PVR as the Stratum II clays. However, in order to effect a PVR reduction to the order of 1 to 1-1/2 in. all of the Stratum I materials and from 2 to 4 feet of the stratum II clays will have to be removed and replaced with select fill. Lime treated on-site clays could be considered for use as select fill at this site. We anticipate that the Stratum I fill soils will be too gravelly for lime stabilization but the Stratum II clays could be considered for this option. We do not anticipate that there will be enough of the Stratum II clays excavated to construct the entire building pad it could be used for construction of the lower lifts of the building pad and imported select structural fill could be used to construct the building pad up to the required building pad elevation. PVR values have been estimated for overexcavation and select fill replacement to various depths below the existing ground surface and are summarized in the table below. Recommendations for the selection and placement of select backfill materials are addressed in a subsequent section of this report.


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Depth of Overexcavation and Select Fill Replacement

(ft)*

Estimated PVR

(in.)

0 4-3/4

2 3-3/4

4 2-3/4

6 2-1/4

8 1-3/4

10 1 *below the ground surface elevation existing at the time of our study.

To maintain the estimated PVR values, subsequent fill placed in the building area should consist of select fill material in accordance with the Select Fill section of this report. Drainage Considerations When overexcavation and select fill replacement is selected as a method to reduce the potential for expansive soil-related movements at any site, considerations of surface and subsurface drainage may be crucial to construction and adequate foundation performance of the soil-supported structures. Filling an excavation in relatively impervious plastic clays with relatively pervious select fill material creates a bathtub beneath the structure, which can result in ponding or trapped water within the fill unless good surface and subsurface drainage is provided. Water entering the fill surface during construction or entering the fill exposed beyond the building lines after construction may create problems with fill moisture control during compaction and increased access for moisture to the underlying expansive clays both during and after construction. Several surface and subsurface drainage design features and construction precautions can be used to limit problems associated with fill moisture. These features and precautions may include but are not limited to the following:

Installing berms or swales on the uphill side of the construction area to divert surface runoff away from the excavation/fill area during construction;

Sloping of the top of the subgrade with a minimum downward slope of 1.5 percent out to the base of a dewatering trench located beyond the building perimeter;

Sloping the surface of the fill during construction to promote runoff of rain water to drainage features until the final lift is placed;

Sloping of a final, well maintained, impervious clay or pavement surface (downward away from the building) over the select fill material and any perimeter drain extending beyond the building lines, with a minimum gradient of 6 in. in 5 ft;

Constructing final surface drainage patterns to prevent ponding and limit surface water infiltration at and around the building perimeter;


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Locating the water-bearing utilities, roof drainage outlets and irrigation spray heads outside of the select fill and perimeter drain boundaries; and

Raising the elevation of the ground level floor slab. Details relative to the extent and implementation of these considerations must be evaluated on a project-specific basis by all members of the project design team. Many variables that influence fill drainage considerations may depend on factors that are not fully developed in the early stages of design. For this reason, drainage of the fill should be given consideration at the earliest possible stages of the project.

FOUNDATION RECOMMENDATIONS FOUNDATION OPTIONS The following recommendations are based on the data obtained from our field and laboratory studies, our past experience with geotechnical conditions similar to those at this site, and our engineering design analyses. The following alternatives are available to support the structure:

Drilled-and-underreamed piers; Rigid-engineered beam and slab foundation.

Due to the highly expansive nature of the clays at this site, a deep foundation system with a structurally suspended floor system is expected to provide the foundation system least susceptible to expansive soil related movements. We recommend that consideration be given to founding the structure on deep drilled-and-underreamed piers with a structurally suspended floor system and superstructure. For this option a permanent void space (crawl space) would be constructed beneath the building. A rigid engineered slab on grade foundation is not recommended unless it is constructed on a properly engineered select structural fill pad that reduces the expansive soil related movements (PVR) to acceptable structural and operational tolerances. The owner may select either one of these foundation systems depending on the performance criteria established for this structure. Cost analyses have not been conducted for any foundation system and are beyond the scope of this study. SITE GRADING Site grading plans can result in changes in almost all aspects of foundation recommendations. We have prepared all foundation recommendations based on the existing ground surface and the stratigraphic conditions encountered at the time of our study. If site grading plans differ from existing grade by more than plus or minus 1 ft, RKCI must be retained to review the site grading plans prior to bidding the project for construction. This will enable RKCI to provide input for any changes in our original recommendations that may be required as a result of site grading operations or other considerations.


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AREA FLATWORK It should be noted that ground-supported flatwork such as walkways, courtyards, etc. will be subject to the same magnitude of potential soil-related movements as discussed previously (see Expansive Soil-Related Movement section). Thus, where these types of elements abut rigid building foundations or isolated/suspended structures, differential movements should be anticipated. As a minimum, we recommend that flexible joints be provided where such elements abut the main structure to allow for differential movement at these locations. Where the potential for differential movement is objectionable, it may be beneficial to consider methods of reducing anticipated movements or to consider structurally suspending critical areas to match the adjacent building performance. If differential movement of the flatwork connected to or adjacent to a slab on select fill structure is unacceptable then the ground modification/treatment for the building should be extended to beneath the areas of critical utilities and/or flatwork. Short structural bridging elements, constructed partially on cardboard carton forms (void forms), can provide a hinge or transition from the at-grade flatwork to an adjoining suspended structure. The structural bridging element will need to be doweled into the structures at either end of each element to create a flexible hinge/joint. As the carton forms decompose, this will create a void space giving the underlying highly expansive clay a space to expand without damaging the overlying flatwork. Cardboard carton forms would be used to create a void space beneath the edge of the short structural bridging element at the adjoining suspended structure to prevent it from being sheared off at the hinge interface during the anticipated soil movements. This detail is intended to provide a smooth transition between the slab on grade walkways and the suspended structure. The recommendations above should also be used for transitioning slab on grade walks into building entrances to prevent the slab on grade walkway from heaving and blocking entry doors from opening to the outside and from creating trip hazards. Precautions must be taken not to undermine or damage existing grade beams, footings, and/or utility lines where excavations adjacent to existing structures are required. DRILLED-AND-UNDERREAMED PIERS Drilled-and-underreamed piers bearing in/on the Stratum IV clayshale may be considered to support the structure. We recommend that piers extend to a minimum depth of 30 ft below the ground surface existing at the time of our study. The piers should be designed as end bearing units using a maximum allowable bearing pressure of 18 ksf. This bearing pressure was evaluated using a calculated factor of safety of at least 3 with respect to the design shear strength. Based on the 40-ft maximum depth of exploration, pier depth should not exceed a depth of 40 ft below the ground surface existing at the time of our study. Furthermore, as discussed in a previous section of this report, it has been our past experience that shallow groundwater seepage will be encountered at this project site. Therefore, we recommend that the bid documents require the foundation contractor to specify unit costs for different lengths of casing that may be required for the successful construction of the drilled piers.


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Pier Shaft Potential Uplift Forces The pier shafts will be subject to potential uplift forces if the surrounding expansive soils within the active zone are subjected to alternate drying and wetting conditions. The maximum potential uplift force acting on the shaft may be estimated by:

Fu = 80*D where:

Fu = uplift force in kips; and D = diameter of the shaft in feet.

Allowable Uplift Resistance Resistance to uplift forces exerted on the drilled piers will be provided by the sustained axial compressive force (dead load) plus the allowable uplift resistance provided by the soil. The resistance provided by the soil depends on the bearing capacity of the soils located above the pier underream (bell) and below the active zone. The allowable uplift resistance for underreamed piers founded at the depth recommended above may be estimated using:

Ru = 14*(B2 - D2) where:

Ru = uplift resistance in kips; B = diameter of the underream in feet; and D = diameter of the shaft in feet.

We recommend that the bell-to-shaft diameter ratio be a minimum of 2, and not exceed 3. Reinforcing steel will be required in each pier shaft to withstand a net force equal to the uplift force minus the sustained compressive load carried by the pier. We recommend that each pier be reinforced to withstand this net force or an amount equal to 1 percent of the cross-sectional area of the shaft, whichever is greater. PIER SPACING Where possible, we recommend that the piers be spaced at a center to center distance of at least three bell-diameters for underreamed piers. Such spacing will not require a reduction in the load carrying capacity of the individual piers. If design and/or construction restraints require that piers be spaced closer than the recommended three bell diameters, RKCI must re-evaluate the allowable bearing capacities presented above for the individual piers. Reductions in load carrying capacities may be required depending upon individual loading and spacing conditions.


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SUSPENDED FLOOR SLAB Floor slabs which have high performance criteria or which are movement sensitive in nature, should be structurally suspended because of the anticipated ground movements. A positive void space of at least 12 in., preferably more, should be provided between the slab and the underlying soils (see also Crawl Space Considerations). Areas of critical entry/exit points to the building, such as doorways, should consider using a suspended system to relieve those areas of heave stresses caused by expansive soils. We recommend that the grade beams interconnecting the piers be structurally suspended due to the anticipated ground movements. A positive void space of at least 12 in., preferably more, should be provided between the soffits of grade beams and the underlying soils.

ENGINEERED BEAM AND SLAB FOUNDATION Shallow, slab-on-grade foundations may be considered to support the structure. The proposed structure may be founded on a stiffened engineered beam and slab foundation, provided the selected foundation type can be designed to withstand the anticipated soil-related movements (see Expansive Soil-Related Movements) without impairing either the structural or the operational performance of the structure. If a shallow foundation is to be considered, we recommend that overexcavation and select fill replacement be utilized to reduce expansive soil-related movements to within acceptable structural and operational tolerances. Allowable Bearing Capacity Shallow foundations founded on compacted, select fill should be proportioned using the design parameters tabulated below.

Minimum depth below final grade 18 in.

Minimum beam width 12 in.

Minimum widened beam width 18 in.

Maximum allowable bearing pressure for grade beams 2,500 psf

Maximum allowable bearing pressure for widened beams 3,000 psf

The above presented maximum allowable bearing pressures will provide a calculated factor of safety of about 3 with respect to the measured shear strength, provided that fill is selected and placed as recommended in the Select Fill section of this report. We recommend that a vapor barrier comprised of polyethylene or polyvinylchloride (PVC) sheeting be placed between the supporting soils and the concrete floor slab.


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FOUNDATION CONSTRUCTION CONSIDERATIONS SITE DRAINAGE Drainage is an important key to the successful performance of any foundation. Good surface drainage should be established prior to and maintained after construction to help prevent water from ponding within or adjacent to the building foundation and to facilitate rapid drainage away from the building foundation. Failure to provide positive drainage away from the structure can result in localized differential vertical movements in soil supported foundations and floor slabs (which can in turn result in cracking in the sheetrock partition walls, and shifting of ceiling tiles, as well as improper operation of windows and doors). Current ordinances, in compliance with the Americans with Disabilities Act (ADA), may dictate maximum slopes for walks and drives around and into new buildings. These slope requirements can result in drainage problems for buildings supported on expansive soils. We recommend that, on all sides of the building, the maximum permissible slope be provided away from the building. Also to help control drainage in the vicinity of the structure, we recommend that roof/gutter downspouts and landscaping irrigation systems not be located adjacent to the building foundation. Where a select fill overbuild is provided outside of the floor slab/foundation footprint, the surface should be sealed with an impermeable layer (pavement or clay cap) to reduce infiltration of both irrigation and surface waters. Careful consideration should also be given to the location of water bearing utilities, as well as to provisions for drainage in the event of leaks in water bearing utilities. All leaks should be immediately repaired. Other drainage and subsurface drainage issues are discussed in the Expansive Soil-Related Movements section of this report and under Pavement Construction Considerations. Furthermore, as discussed in a previous section of this report, it has been our past experience that shallow groundwater seepage may be encountered at this project site. Based on proposed site grading, we recommend that drainage related issues be thoroughly addressed by the design team. SITE PREPARATION Building areas and all areas to support select fill should be stripped of all vegetation and organic topsoil. Furthermore, as discussed in a previous section of this report, if a ground-supported floor system is chosen for the proposed structure, we recommend that overexcavation and select fill replacement be utilized to reduce expansive soil-related movements to within acceptable structural and operational tolerances. Exposed subgrades should be thoroughly proofrolled in order to locate weak, compressible zones. A fully-loaded dump truck or a similar heavily-loaded piece of construction equipment should be used for planning purposes. Proofrolling operations should be observed by the Geotechnical Engineer or their representative to document subgrade condition and preparation. Weak or soft areas identified during proofrolling should be removed and replaced with suitable, compacted on-site clays, free of organics, oversized materials, and degradable or deleterious materials.


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Upon completion of the proofrolling operations and just prior to fill placement or slab construction, the exposed subgrade should be moisture conditioned by scarifying to a minimum depth of 6 in. and recompacting to a minimum of 95 percent of the maximum density determined from TxDOT, Tex-114-E, Compaction Test. The moisture content of the subgrade should be maintained within the range of optimum moisture content to 3 percentage points above optimum moisture content until permanently covered. SELECT FILL Select fill material can consist of lime treated Stratum II clays and/or imported granular select fill. Imported materials used as select fill and for final site grading preferably should be crushed stone or gravel aggregate. We recommend that materials specified for use as select fill meet the TxDOT 2004 Standard Specifications for Construction and Maintenance of Highways, Streets and Bridges, Item 247, Flexible Base, Type A or C, Grades 1 through 3. Soils classified as CH, CL, MH, ML, SM, GM, OH, OL and Pt under the USCS are not considered suitable for use as select fill materials at this site. The native soils at this site are not considered suitable for use as select fill materials. However, provided that they are treated in accordance with the recommendations presented in the Lime Treatment of Soils section of this report the Stratum II clays may be used for the construction of the deeper lifts of the select fill building pad. Select fill should be placed in loose lifts not exceeding 8 in. in thickness and compacted to at least 95 percent of maximum density as determined by TxDOT, Tex-113-E, Compaction Test. The moisture content of the fill should be maintained within the range of 2 percentage points below to 2 percentage points above the optimum moisture content until final compaction. LIME TREATMENT OF SOILS Lime treatment of the Stratum II clays should be in accordance with the TxDOT Standard Specifications, Item 260. A sufficient quantity of hydrated lime should be mixed with the clay soils to reduce the soil-lime mixture plasticity index to 15 or less. For estimating purposes, we recommend that 5 percent lime by weight be assumed for treatment. For construction purposes, we recommend that the optimum lime content of the clay soils be determined by laboratory testing. Lime-treated clay soils should be compacted to a minimum of 95 percent of the maximum density at a moisture content within the range of optimum moisture content to 3 percentage points above the optimum moisture content as determined by Tex-114-E. If lime treatment is considered as a method to partially construct a select fill building pad it is recommended to perform additional laboratory testing to determine the concentration of soluble sulfates in the clay soils, in order to investigate the potential for a recently reported adverse reaction to lime in certain sulfate-containing soils. The adverse reaction, referred to as sulfate-induced heave, has been known to cause cohesive subgrade soils to swell in short periods of time, resulting in pavement heaving and possible failure.


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SHALLOW FOUNDATION EXCAVATIONS Shallow foundation excavations should be observed by the Geotechnical Engineer or their representative prior to placement of reinforcing steel and concrete. This is necessary to observe that the bearing soils at the bottom of the excavations are as recommended for the rigid engineered beam and slab foundation system and that excessive loose materials and water are not present in the excavations. If soft pockets of soil are encountered in the foundation excavations, they should be removed and replaced with a compacted non-expansive fill material or lean concrete up to the design foundation bearing elevations. It should also be noted that the surficial fill materials located at this site are gravelly in nature; consequently, these soils will be very susceptible to small changes in moisture content and to disturbance from foot traffic during the construction of utility trenches, particularly in periods of inclement weather. Disturbance from such foot traffic and from the accumulation of excess water can result in sloughing of trench walls and increased settlement. If inclement weather is anticipated at the time construction, consideration should be given to protecting the bottoms of beam trenches by placing a thin mud mat (layer of flowable fill or lean concrete) at the bottom of trenches immediately following excavation. This will reduce disturbance from foot traffic and will impede the infiltration of surface water. The side slopes of the trench excavations may also need to be flattened to reduce sloughing in cohesionless soils. All necessary precautions should be implemented to protect open excavations from the accumulation of surface water runoff and rain. DRILLED PIERS Each drilled pier excavation must be examined by an RKCI representative who is familiar with the geotechnical aspects of the soil stratigraphy, the structural configuration, foundation design details and assumptions, prior to placing concrete. This is to observe that:

The shaft and/or bell has been excavated to the specified dimensions at the correct depth established by the previously mentioned criteria;

An acceptable portion of the shaft penetrates intact clayshale versus weathered and/or clay seams;

The bell is concentric with the pier shaft; The shaft has been drilled plumb within specified tolerances along its total length; and Excessive cuttings, buildup and soft, compressible materials have been removed from

the bottom of the excavation. Due to the presence of clayshale, high-powered, high-torque drilling equipment should be anticipated for drilled pier construction at this site (see also Excavation Equipment). Reinforcement and Concrete Placement Reinforcing steel should be checked for size and placement prior to concrete placement. Placement of concrete should be accomplished as soon as possible after excavation to reduce changes in the moisture


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content or the state of stress of the foundation materials. No foundation element should be left open overnight without concreting. Temporary Casing Groundwater seepage was observed in one of the test borings at the time of our subsurface exploration. Groundwater seepage and/or side sloughing is likely to be encountered at the time of construction, depending on climatic conditions prevalent at the time of construction. Therefore, we recommend that the bid documents require the foundation contractor to specify unit costs for different lengths of casing that may be required. EXCAVATION SLOPING AND BENCHING If utility trenches or other excavations extend to or below a depth of 5 ft below construction grade, the contractor or others shall be required to develop a trench safety plan to protect personnel entering the trench or trench vicinity. The collection of specific geotechnical data and the development of such a plan, which could include designs for sloping and benching or various types of temporary shoring, are beyond the scope of the current study. Any such designs and safety plans shall be developed in accordance with current OSHA guidelines and other applicable industry standards. EXCAVATION EQUIPMENT Our boring logs are not intended for use in determining construction means and methods and may therefore be misleading if used for that purpose. We recommend that earth-work and utility contractors interested in bidding on the work perform their own tests in the form of test pits to determine the quantities of the different materials to be excavated, as well as the preferred excavation methods and equipment for this site. CRAWL SPACE CONSIDERATIONS If a structurally suspended floor system is selected for this structure several special design issues should be considered for the resulting subfloor crawl space. These issues are discussed below. Ventilation Observations by members of our firm of open crawl spaces have indicated a need for adequate subfloor ventilation for suspended floor systems. Such ventilation helps promote evaporation of subgrade moisture which may accumulate in spite of special surface and subsurface drainage features. As a minimum, free flowing passive vents may need to be installed along the perimeter beam to provide cross ventilation. If structural configurations will limit the free flow of air through passive vents, forced air, power vents should be installed. All vents should be designed such that they will not allow the drainage of surface water into the crawl space.


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Below Slab Utilities A minimum clearance of 12 in. has been recommended between both the grade beams and floor slab and the underlying finished subgrade should a suspended floor system be employed. Such a minimum clearance is also recommended between the subgrade and any utilities which may be suspended from the underside of the floor. This clearance will allow swell-related subgrade movements without damaging the utilities. It is recommended that the utility clearance not be provided by the addition of narrow trenches running parallel to and immediately below the utilities, unless proper slopes and drainage outlets are provided to prevent ponding of water in the trenches. Drainage As discussed throughout this report, positive drainage is a key factor in the long term performance of any foundation. This is not only critical around the perimeter of the structure, but also in any subfloor crawl spaces. In crawl areas, surface drainage should be established that will direct water away from and will prevent water from ponding adjacent to piers. This positive drainage should be maintained both prior to and after construction. Compaction control of the backfill around the perimeter of the building following the placement of soil retainer blocks is critical to the drainage away from the building following construction. Materials for the backfill around the perimeter of the building should be the on-site clays. These materials should be compacted in uniformly thin lifts (8-inch maximum loose thickness) to at least 90 percent of the maximum dry density as determined by TxDOT Test Method TEX-114-E. These clays should be placed and compacted at optimum to plus 3 percent above optimum moisture content. Compaction by hand operated mechanical tampers will help to avoid damage to the soil retainer blocks. Following backfilling operations the soil retainer blocks should be checked to see that they have not been broken or collapsed during the compaction operations. Any soil retainer blocks that are broken or collapsed should be repaired or replaced. Carton Forms When carton forms are used to form subfloor void spaces, the forms often get wet or sometimes absorb water from humid air. This can result in collapse of the forms during the placement of concrete, thus diminishing the design void space. Conversely, if the carton forms are too strong and do not decompose sufficiently with time, they may not collapse as soil heave occurs, resulting in heave damage to the floor slab. Where there is sufficient moisture to cause the appropriate deterioration after construction, there may be a resulting moisture problem in the floor slab as a result of poor ventilation and the accumulation of condensation within the resulting unventilated void space. The lack of ventilation may also result in increased soil movements that will diminish the design void space. For these reasons, we recommend that where possible, consideration be given to methods other than the use of carton forms to form the recommended void space beneath floor slabs. If project specifics require the use of carton forms, then as a minimum, care should be taken to ensure that the carton forms are designed for use in the project location, and that carton forms are properly stored, protected, and installed during construction.


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UTILITIES Utilities which project through slab-on-grade, slab-on-fill, a suspended floor slab or any other rigid unit should be designed with either some degree of flexibility or with sleeves. Such design features will help reduce the risk of damage to the utility lines as vertical movements occur. Our experience indicates that significant settlement of backfill can occur in utility trenches, particularly when trenches are deep, when backfill materials are placed in thick lifts with insufficient compaction, and when water can access and infiltrate the trench backfill materials. The potential for water to access the backfill is increased where water can infiltrate flexible base materials due to insufficient penetration of curbs, and at sites where geological features can influence water migration into utility trenches (such as fractures within a rock mass or at contacts between rock and clay formations). It is our belief that another factor which can significantly impact settlement is the migration of fines within the backfill into the open voids in the underlying free-draining bedding material. To reduce the potential for settlement in utility trenches, we recommend that consideration be given to the following:

All backfill materials should be placed and compacted in controlled lifts appropriate for the type of backfill and the type of compaction equipment being utilized and all backfilling procedures should be tested and documented.

Curbs should completely penetrate base materials and be installed to a sufficient depth to reduce water infiltration beneath the curbs into the pavement base materials.

Consideration should be given to wrapping free-draining bedding gravels with a geotextile fabric (similar to Mirafi 140N) to reduce the infiltration and loss of fines from backfill material into the interstitial voids in bedding materials.

PAVEMENT RECOMMENDATIONS

Recommendations for both flexible and rigid pavements are presented in this report. The Owner and/or design team may select either pavement type depending on the performance criteria established for the project. In general, flexible pavement systems have a lower initial construction cost as compared to rigid pavements. However, maintenance requirements over the life of the pavement are typically much greater for flexible pavements. This typically requires regularly scheduled observation and repair, as well as overlays and/or other pavement rehabilitation at approximately one-half to two-thirds of the design life. Rigid pavements are generally more "forgiving", and therefore tend to be more durable and require less maintenance after construction. For either pavement type, drainage conditions will have a significant impact on long term performance, particularly where permeable base materials are utilized in the pavement section. Drainage considerations are discussed in more detail in a subsequent section of this report.


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SUBGRADE CONDITIONS We have assumed the subgrade in pavement areas will consist of the recompacted on-site clays, placed and compacted as recommended in the On-Site Clay Fill section of this report. Based on our experience with similar subgrade soils, we have assigned a California Bearing Ratio (CBR) value of 3.0 for use in pavement thickness design analyses. DESIGN INFORMATION The following recommendations were prepared using the DARWin 3.01 software program which utilizes a procedure based on the 1993 Guide for the Design of Pavement Structures by the American Association of State Highway and Transportation Officials (AASHTO). The following recommendations were prepared assuming a 20-yr design life and Equivalent Single Axle Loads (ESALs) listed in the table below. The number of ESALs per bus was evaluated assuming two axles, with a 10-kip load acting on the front axle and a 20-kip load acting on the rear axle. At the time of this report, we did not have specific traffic loading information, so we have provided information for various numbers of buses per day. Therefore, the Project Civil Engineer and/or Architect should review anticipated traffic loading and frequencies to verify that the assumed traffic loading and frequency is appropriate for the intended use of the facility. If loading conditions differ from those assumed in this report, RKCI should be notified so that we may revise our recommendations.

Pavement Type Assumed Traffic Type and Frequency Assumed

ESALs

Light Duty Pavements Automobiles and pickup trucks only 15,000

Medium Duty Pavements Entrances, driveways, and channelized traffic

and/or bus traffic of 3 buses, twice a day 50,000

Heavy Duty Pavement w/ 10 Buses 10 buses, twice a day 160,000

Heavy Duty Pavement w/ 30 Buses 30 buses, twice a day 480,000

FLEXIBLE PAVEMENT Flexible pavement sections recommended for this site are as listed in the table below:

Flexible Pavement Components

Flexible Base (in.)

Surface Course (in.)

Light Duty Pavements 8 2

Medium Duty Pavements 9 2-1/2

Heavy Duty Pavements w/ 10 Buses 10 3

Heavy Duty Pavements w/ 30 Buses 12 3-1/2


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As previously reported the gravelly nature of the surficial fill soils make lime treatment of these materials impractical therefore lime treated subgrade is not considered to be an option at this site. Past experience with flexible base pavement sections on expansive soils indicates that the use of a geogrid base reinforcement (such as TENSAR TX-5) provides considerable tensile strength to the pavement section. This tensile strength is achieved without making the section more brittle, as occurs with many other subgrade or base stabilization methods. The added tensile strength and flexibility allows the pavement section to move and flex, as the expansive clays undergo the normal shrink and swell with changes in climatic conditions, with considerably less cracking and premature deterioration than otherwise typically occurs. For these reasons, consideration may be given to adding geogrid to both the pavement sections for this project. In these instances we do not recommend that the pavement sections be decreased from those recommended in the table above. Garbage Dumpsters Where flexible pavements are constructed at any site, we recommend that reinforced concrete pads be provided in front of and beneath trash receptacles. The dumpster trucks, if any, should be parked on the rigid pavement when the receptacles are lifted. It is suggested that such pads also be provided in drives where the dumpster trucks make turns with small radii to access the receptacles. The concrete pads at this site should be a minimum of 6 in. thick and reinforced with conventional steel reinforcing bars or welded wire mats. RIGID PAVEMENT We recommend that rigid pavements be considered in areas of channelized traffic, particularly in areas where bus traffic is planned, and particularly where such traffic will make frequent turns, such as described above for garbage dumpster areas. We recommend that rigid pavement sections at this site consist of the following:

Traffic Type Portland Cement Concrete

Light Duty Traffic 6 in.

Heavy Duty Traffic 7 in.

We recommend that the concrete pavements be reinforced with welded wire mats or bar mats. As a minimum, the welded wire mats should be 6 x 6 in., W4.0 x W4.0, and the bar mats should be No. 3 reinforcing bars spaced 18 in. on center in both directions. The concrete reinforcing should be placed approximately 1/3 the slab thickness below the surface of the slab, but not less than 2 in. The reinforcing should not extend across expansion joints. Joints in concrete pavements aid in the construction and control the location and magnitude of cracks. Where practical, lay out the construction, expansion, control and sawed joints to form square panels, but not to exceed ACI 302.69 Code recommendations. The ratio of slab length-to-width should not exceed 1.25. Recommended joint spacings are 15 ft longitudinal and 15 ft transverse.


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All control joints should be formed or sawed to a depth of at least 1/4 the thickness of the concrete slab. Sawing of control joints should begin as soon as the concrete will not ravel, generally the day after placement. Control joints may be hand formed or formed by using a premolded filler. We recommend that all longitudinal and transverse construction joints be dowelled to promote load transfer. Expansion joints are needed to separate the concrete slab from fixed objects such as drop inlets, light standards and buildings. Expansion joint spacings are not to exceed a maximum of 75 ft and no expansion or construction joints should be located in a swale or drainage collection locations. If possible, the pavement should develop a minimum slope of 0.015 ft/ft to provide surface drainage. Reinforced concrete pavement should cure a minimum of 3 and 7 days before allowing automobile and truck traffic, respectively.

PAVEMENT CONSTRUCTION CONSIDERATIONS SUBGRADE PREPARATION Areas to support pavements should be stripped of all vegetation and organic topsoil and the exposed subgrade should be proofrolled in accordance with the recommendations in the Site Preparation section under Foundation Construction Considerations. After completion of the proofrolling operations and just prior to flexible base placement, the exposed subgrade should be moisture conditioned by scarifying to a minimum depth of 6 in. and recompacting to a minimum of 95 percent of the maximum density determined from the Texas Department of Transportation Compaction Test (TxDOT, Tex-114-E). The moisture content of the subgrade should be maintained within the range of optimum moisture content to 3 percentage points above optimum until permanently covered. DRAINAGE CONSIDERATIONS As with any soil-supported structure, the satisfactory performance of a pavement system is contingent on the provision of adequate surface and subsurface drainage. Insufficient drainage which allows saturation of the pavement subgrade and/or the supporting granular pavement materials will greatly reduce the performance and service life of the pavement systems. Surface and subsurface drainage considerations crucial to the performance of pavements at this site include (but are not limited to) the following:

1) Any known natural or man-made subsurface seepage at the site which may occur at sufficiently shallow depths as to influence moisture contents within the subgrade should be intercepted by drainage ditches or below grade French drains.

2) Final site grading should eliminate isolated depressions adjacent to curbs which may allow surface water to pond and infiltrate into the underlying soils. Curbs should completely penetrate base materials and should be installed to sufficient depth to reduce infiltration of water beneath the curbs.


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3) Pavement surfaces should be maintained to help minimize surface ponding and to provide rapid sealing of any developing cracks. These measures will help reduce infiltration of surface water downward through the pavement section.

ON-SITE CLAY FILL As discussed previously, the pavement recommendations presented in this report were prepared assuming that on-site soils will be used for fill grading in proposed pavement areas. If used, we recommend that on-site soils be placed in loose lifts not exceeding 8 in. in thickness and compacted to at least 95 percent of the maximum density as determined by TxDOT, Tex-114-E. The moisture content of the fill should be maintained within the range of optimum water content to 3 percentage points above the optimum water content until permanently covered. We recommend that fill materials be free of roots and other organic or degradable material. We also recommend that the maximum particle size not exceed 4 in. or one half the lift thickness, whichever is smaller. GEOGRID REINFORCEMENT If utilized geogrid reinforcement should be Tensar TX-5. An approved source of geogrid is The Tensar Corporation, Morrow, GA or their designated representative. The geogrid component shall be integrally formed and produced from a punched sheet of polypropylene which is then oriented in three substantially equilateral directions so that the resulting ribs shall have a high degree of molecular orientation, which continues at least in part through the mass of the integral node. The resulting geogrid structure shall have apertures that are triangular in shape, and shall have ribs with a depth-to-width ratio greater than 1.0. The geogrid shall have the nominal characteristics shown in the table below, and shall be certified in writing by the manufacturer to be TX-5:

Properties Longitudinal Diagonal Transverse General

Rib pitch, mm (in.) 40 (1.60) 40 (1.60) - -

Mid-rib depth, mm (in.) - 1.3 (0.05) 1.2 (0.05) -

Mid-rib width, mm (in.) - 0.9 (0.04) 1.2 (0.05) -

Rib shape - - - Rectangular

Aperture shape - - - Triangular The geogrid should be placed at the bottom of the flexible (granular) base section in all cases. An alternative to the above geogrid should not be considered without approval from RKCI.


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FLEXIBLE BASE COURSE The flexible base course should be crushed limestone conforming to TxDOT Standard Specifications, Item 247, Type A, Grades 1 or 2. Base course should be placed in lifts with a maximum thickness of 8 in. and compacted to a minimum of 95 percent of the maximum density at a moisture content within the range of 2 percentage points below to 2 percentage points above the optimum moisture content as determined by Tex-113-E. ASPHALTIC CONCRETE SURFACE COURSE The asphaltic concrete surface course should conform to TxDOT Standard Specifications, Item 340, Type D. The asphaltic concrete should be compacted to a minimum of 92 percent of the maximum theoretical specific gravity (Rice) of the mixture determined according to Test Method Tex-227-F. Pavement specimens, which shall be either cores or sections of asphaltic pavement, will be tested according to Test Method Tex-207-F. The nuclear-density gauge or other methods which correlate satisfactorily with results obtained from project roadway specimens may be used when approved by the Engineer. Unless otherwise shown on the plans, the Contractor shall be responsible for obtaining the required roadway specimens at their expense and in a manner and at locations selected by the Engineer. PORTLAND CEMENT CONCRETE The Portland cement concrete should be air entrained to result in a 4 percent plus/minus 1 percent air, should have a maximum slump of 5 inches, and should have a minimum 28-day compressive strength of 3,000 psi. A liquid membrane-forming curing compound should be applied as soon as practical after broom finishing the concrete surface. The curing compound will help reduce the loss of water from the concrete. The reduction in the rapid loss in water will help reduce shrinkage cracking of the concrete. The Mr of concrete is a measure of the flexural strength of the concrete as determined by breaking concrete beam test specimens. A Mr of approximately 450 to 550 psi at 28 days was used in the analysis and is typical of local concrete production.

CONSTRUCTION RELATED SERVICES CONSTRUCTION MATERIALS TESTING AND OBSERVATION SERVICES As presented in the attachment to this report, Important Information About Your Geotechnical Engineering Report, subsurface conditions can vary across a project site. The conditions described in this report are based on interpolations derived from a limited number of data points. Variations will be encountered during construction, and only the geotechnical design engineer will be able to determine if these conditions are different than those assumed for design.


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Construction problems resulting from variations or anomalies in subsurface conditions are among the most prevalent on construction projects and often lead to delays, changes, cost overruns, and disputes. These variations and anomalies can best be addressed if the geotechnical engineer of record, RKCI is retained to perform construction observation and testing services during the construction of the project. This is because:

RKCI has an intimate understanding of the geotechnical engineering reports findings and recommendations. RKCI understands how the report should be interpreted and can provide such interpretations on site, on the clients behalf.

RKCI knows what subsurface conditions are anticipated at the site. RKCI is familiar with the goals of the owner and project design professionals, having

worked with them in the development of the geotechnical workscope. This enables RKCI to suggest remedial measures (when needed) which help meet the owners and the design teams requirements.

RKCI has a vested interest in client satisfaction, and thus assigns qualified personnel whose principal concern is client satisfaction. This concern is exhibited by the manner in which contractors work is tested, evaluated and reported, and in selection of alternative approaches when such may become necessary.

RKCI cannot be held accountable for problems which result due to misinterpretation of our findings or recommendations when we are not on hand to provide the interpretation which is required.

BUDGETING FOR CONSTRUCTION TESTING Appropriate budgets need to be developed for the required construction testing and observation activities. At the appropriate time before construction, we advise that RKCI and the project designers meet and jointly develop the testing budgets, as well as review the testing specifications as it pertains to this project. Once the construction testing budget and scope of work are finalized, we encourage a preconstruction meeting with the selected contractor to review the scope of work to make sure it is consistent with the construction means and methods proposed by the contractor. RKCI looks forward to the opportunity to provide continued support on this project, and would welcome the opportunity to meet with the Project Team to develop both a scope and budget for these services.

* * * * * * * * * * * * * * * * * *

ATTACHMENTS

!?

!?B-2

B-1

BORING LOCATION MAPFT SAM HOUSTON ISD

BAND HALL AND MUSIC BUILDINGSAN ANTONIO, TEXAS

PROJECT No.:ASA14-066-00

DRAWN BY:ISSUE DATE:

REVIEWED BY:CHECKED BY:

2012 by Raba-Kistner Consultants, Inc.c

MJR08/12/2014

GLBMJR

NOT E: Th is Draw in g i s P ro vide d for I l lu s tra tio n O n ly, M ay No t b e to Sca le a nd i s N ot S ui tab le for D es ig n or C o nstr uct io n P ur p oses

LEGEND!? BORING

SOURCE: 20 13 Aerial Photograph Obtained from the City of San Antonio (COSA)

San AntonioTerrell Hills

Kirby

35

410

UV368

BexarFort Sam HoustonFort Sam Houston

SSaa llaa ddoo CC rree eekk

WWaa llzzeemm CC rr

ee ee kk

SITE LOCATION MAP

S I T E

FIGURE 1BEXARCOUNT Y

_

TBPE Firm Number 3257

12821 West Golden LaneSan Antonio, Texas 78249

(210)699-9090 TEL(210)699-6426 FAX

www.rkci.com

0 50 10025FEET

1 INCH = 100 FEET

FILL MATERIAL: GRAVEL, Clayey, MediumDense to Dense, Dark Brown, with chert

- with a gravelly clay seam below 5 ft

CLAY, Stiff to Very Stiff, Dark Brown

CLAY, Hard, Tan and Gray

- with gypsum from 18 to 25 ft

CLAYSHALE, Hard, Gray

37

47

44

49

52

LOG OF BORING NO. B-1

PLA

STIC

ITY

IND

EX

Straight Flight Auger

% -2

00

DRILLINGMETHOD: LOCATION:

PLASTICLIMIT

LIQUIDLIMIT

WATERCONTENT

BLO

WS

PER

FT

10 20 30 40 50 60 70 80

DESCRIPTION OF MATERIAL0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

SHEAR STRENGTH, TONS/FT2

UN

IT D

RYW

EIG

HT,

pcf

N 29.48096; W 98.41974

NO

TE: T

HES

E LO

GS

SHO

ULD

NO

T BE

USE

D S

EPAR

ATEL

Y FR

OM

TH

E PR

OJE

CT R

EPO

RT

DEPTH DRILLED:DATE DRILLED:

DEPTH TO WATER:DATE MEASURED:

5

10

15

20

25

30

35

SYM

BOL

SAM

PLES

Ft Sam Houston ISDBand Hall and Music Building

San Antonio, Texas

Dry8/29/2014

DEP

TH, F

T

38.6 ft8/29/2014

ASA14-066-002

PROJ. No.:FIGURE:

TBPE Firm Registration No. F-3257

45

26

24

11

18

47

38

49

ref/6"

ref/2"

ref/2"

FILL MATERIAL: GRAVEL, Clayey, Dense,Dark Brown, with chert

DRILLER'S NOTE: WATER encoutnered at 8 ft

CLAY, Very Stiff to Hard, Tan and Gray

CLAYSHALE, Hard, Gray

44

51

41

18

LOG OF BORING NO. B-2

PLA

STIC

ITY

IND

EX

Straight Flight Auger

% -2

00

DRILLINGMETHOD: LOCATION:

PLASTICLIMIT

LIQUIDLIMIT

WATERCONTENT

BLO

WS

PER

FT

10 20 30 40 50 60 70 80

DESCRIPTION OF MATERIAL0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

SHEAR STRENGTH, TONS/FT2

UN

IT D

RYW

EIG

HT,

pcf

N 29.48060; W 98.41985

NO

TE: T

HES

E LO

GS

SHO

ULD

NO

T BE

USE

D S

EPAR

ATEL

Y FR

OM

TH

E PR

OJE

CT R

EPO

RT

DEPTH DRILLED:DATE DRILLED:

DEPTH TO WATER:DATE MEASURED:

5

10

15

20

25

30

35

SYM

BOL

SAM

PLES

Ft Sam Houston ISDBand Hall and Music Building

San Antonio, Texas

13 ft8/29/2014

DEP

TH, F

T

38.6 ft8/29/2014

ASA14-066-003

PROJ. No.:FIGURE:

TBPE Firm Registration No. F-3257

33

33

32

39

38

29

50

50/6"

ref/6"

ref/5"

ref/1"


CLAY-SHALE

SAMPLE TYPES

NO INFORMATION

BLANK PIPE

ASPHALT

IGNEOUS

LIMESTONE

FILL

GEOPROBESAMPLER

TEXAS CONEPENETROMETER

DISTURBED

METAMORPHIC

MARL

MUDROTARY

NORECOVERY SPLIT BARREL

SPLIT SPOONNX CORE

SHELBY TUBE

CALCAREOUS

CLAY

CLAYEY

GRAVEL

GRAVELLY

WELL CONSTRUCTION AND PLUGGING MATERIALS

SILTSTONE

CALICHE

CONGLOMERATE

AIRROTARY

GRABSAMPLE

DOLOMITE

BENTONITE

CORE

SOIL TERMS OTHER

NOTE: VALUES SYMBOLIZED ON BORING LOGS REPRESENT SHEARSTRENGTHS UNLESS OTHERWISE NOTED

BASE

KEY TO TERMS AND SYMBOLS

CUTTINGS

SAND

SANDY

SILT

SILTY

CHALK

STRENGTH TEST TYPES

CEMENT GROUT GRAVEL

SAND

POCKET PENETROMETER

TORVANE

UNCONFINED COMPRESSION

TRIAXIAL COMPRESSIONUNCONSOLIDATED-UNDRAINED

TRIAXIAL COMPRESSIONCONSOLIDATED-UNDRAINED

BRICKS /PAVERS

SCREEN

MATERIAL TYPES

VOLCLAY

SANDSTONE

SHALE

ROCK TERMS

WASTE

CONCRETE/CEMENT

PEAT

BENTONITE &CUTTINGS

CONCRETE/CEMENT

CLAYSTONE

ROTOSONIC-DAMAGED

ROTOSONIC-INTACT

PITCHER

FIGURE 4aREVISED 04/2012


KEY TO TERMS AND SYMBOLS (CONT'D)

TERMINOLOGY

RELATIVE DENSITY PLASTICITYCOHESIVE STRENGTH

PenetrationResistance

Blows per ftDegree ofPlasticity

PlasticityIndex

RelativeDensity

ResistanceBlows per ft

0

4

10

30

-

-

-

-

>

4

10

30

50

50

Very Loose

Loose

Medium Dense

Dense

Very Dense

ConsistencyCohesion

TSF

-

-

-

-

>

-

-

-

-

-

>

Benzene

Toluene

Ethylbenzene

Total Xylenes

Total BTEX

Total Petroleum Hydrocarbons

Not Detected

Not Analyzed

Not Recorded/No Recovery

Organic Vapor Analyzer

Parts Per Million

2

4

8

15

30

30

Very Soft

Soft

Firm

Stiff

Very Stiff

Hard

0

2

4

8

15

0

0.125

0.25

0.5

1.0

-

-

-

-

-

>

0.125

0.25

0.5

1.0

2.0

2.0

0

5

10

20

5

10

20

40

40

None

Low

Moderate

Plastic

Highly Plastic

=

=

=

=

=

=

=

=

=

=

=

ABBREVIATIONS

Qam, Qas, Qal

Qat

Qbc

Qt

Qao

Qle

Q-Tu

Ewi

Emi

Mc

EI

Kknm

Kpg

Kau

=

=

=

=

=

=

=

=

=

=

=

=

=

=

Kef

Kbu

Kdr

Kft

Kgt

Kep

Kek

Kes

Kew

Kgr

Kgru

Kgrl

Kh

Quaternary Alluvium

Low Terrace Deposits

Beaumont Formation

Fluviatile Terrace Deposits

Seymour Formation

Leona Formation

Uvalde Gravel

Wilcox Formation

Midway Group

Catahoula Formation

Laredo Formation

Navarro Group and MarlbrookMarl

Pecan Gap Chalk

Austin Chalk

=

=

=

=

=

=

=

=

=

=

=

=

=

Eagle Ford Shale

Buda Limestone

Del Rio Clay

Fort Terrett Member

Georgetown Formation

Person Formation

Kainer Formation

Escondido Formation

Walnut Formation

Glen Rose Formation

Upper Glen Rose Formation

Lower Glen Rose Formation

Hensell Sand

B

T

E

X

BTEX

TPH

ND

NA

NR

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