geotechnical engineering report - timbercon

Geotechnical Engineering Report

Crosspoint Fellowship Church Additions 2600 Roy Richards Road

Schertz, Texas September 30, 2009

Terracon Project No 90095129

Prepared For: Crosspoint Fellowship Church

2600 Roy Richards Road Schertz, Texas 78154

Prepared By: Terracon Consultants, Inc.

San Antonio, Texas

Geotechnical Engineering Report Crosspoint Fellowship Church Additions ■ Schertz, Texas September 30, 2009 ■ Terracon Project No. 90095129

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TABLE OF CONTENTS

INTRODUCTION ..............................................................................................................................1 PROJECT INFORMATION...............................................................................................................1

Project Description......................................................................................................................1 Site Location and Description ....................................................................................................2

SUBSURFACE CONDITIONS..........................................................................................................2 Site Geology.................................................................................................................................2 Typical Subsurface Profile..........................................................................................................2 Groundwater Conditions.............................................................................................................3

RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION.......................................................3 Geotechnical Considerations .....................................................................................................3 Pad Preparation ...........................................................................................................................4 Slab Foundation...........................................................................................................................5 Spread Footings ..........................................................................................................................6 Drilled Pier Foundations .............................................................................................................7 Seismic Considerations ............................................................................................................11 Interaction with Existing Structures ........................................................................................11 Pavements..................................................................................................................................12 Earthwork ...................................................................................................................................16

GENERAL COMMENTS.................................................................................................................19 TABLE

Table 1 - Slab Foundation Design Criteria

APPENDIX A – FIELD EXPLORATION Vicinity Map Bore Location Plan Boring Logs Field Exploration Description

APPENDIX B – LABORATORY TESTING

Laboratory Testing APPENDIX C – SUPPORTING DOCUMENTS

General Notes Unified Soil Classification ASFE Information

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GEOTECHNICAL ENGINEERING REPORT CROSSPOINT FELLOWSHIP CHURCH ADDITIONS

2600 ROY RICHARDS ROAD SCHERTZ, TEXAS

TERRACON PROJECT NO 90095129

SEPTEMBER 30, 2009 INTRODUCTION Terracon Consultants Inc. (Terracon) is pleased to submit this document which presents the results of our geotechnical engineering services performed for this project. The project involves a building addition to existing church and new pavement areas. The purpose of this report is to describe the subsurface conditions observed at the seven borings drilled for this study, analyze and evaluate the test data, and provide recommendations with respect to:

subsurface soil conditions groundwater conditions earthwork pavements

foundation design and construction

PROJECT INFORMATION Project Description

ITEM DESCRIPTION Site layout See Appendix A, Figures 1 and 2.

Structures New one-story building with a 30-feet parapet height. New pavement areas

Building construction The new building will be constructed of load-bearing CMU blocks and structural steel. The new building may be supported on a slab on grade foundation system.

Finished floor elevation Not available at this time (Anticipated to be at or near existing grades).



Site Location and Description

ITEM DESCRIPTION

Location At 2600 Roy Richards Road, Schertz, Texas

Existing improvements The site is currently undeveloped and is covered with grass and tall trees.

Surrounding developments Existing church and pavement areas.

Existing topography Based on our visual observation, the site is relatively flat. SUBSURFACE CONDITIONS

Site Geology The San Antonio Sheet (1983) of the Geologic Atlas of Texas published by the Bureau of Economic Geology of the University of Texas at Austin has mapped the Pecan Gap Formation (Kpg) of the Upper Cretaceous geologic age in the vicinity of this site. The Pecan Gap Formation typically consists of weathered limestone, chalk and chalky marl. However, this unit typically has a deep weathering profile characterized by deep deposits of expansive clayey soil. Typical Subsurface Profile

Based on the results of the borings, subsurface conditions on the project site can be generalized as follows:

Description Approximate Depth of Stratum (feet) Material Encountered Consistency/Density

Stratum I 0 to 2½ SANDY FAT CLAY1 Very Stiff to Hard

Stratum II 0 to 2½ SANDY LEAN CLAY2 Very Stiff to Hard

Stratum III 2 to 30 WEATHERED LIMESTONE3

Hard

Stratum IV 22 to 30 MARL4 Hard

1 The native SANDY FAT CLAY (CH) materials encountered are expected to have high potential for experience volumetric changes (shrink/swell) with fluctuations in moisture content.

2 The native SANDY LEAN CLAY (CL) materials encountered are expected to have medium to high potential for experience volumetric changes (shrink/swell) with fluctuations in moisture content.

3 WEATHERED LIMESTONE is volumetrically stable when considered for expansive soil-related movements. This material will likely require rock excavation techniques when encountered during construction.



Description Approximate Depth of Stratum (feet) Material Encountered Consistency/Density

4 MARL is defined in ASTM D 653-90 Standard Terminology Relating to Soil, Rock and Contained Fluids as a "…calcareous clay usually containing from 35 to 65 percent calcium carbonate". The calcium carbonate is an indication of a cemented matrix of sand, silt or clay. When submerged in water, marl will begin to slake. However, when being excavated or drilled this material typically behaves more like a rock than soil thereby requiring construction equipment and procedures typically used for rock.

Conditions encountered at each boring location are indicated on the individual boring logs. Stratification boundaries on the boring logs represent the approximate location of changes in soil types; in-situ, the transition between materials may be gradual. Details for each of the borings can be found on the boring logs in Appendix A. Groundwater Conditions

The boreholes were observed while drilling and after completion for the presence and level of groundwater. Groundwater was not encountered in any of the borings during or upon completion of the drilling operations. Groundwater levels are influenced by seasonal and climatic conditions, which generally result in fluctuations in the elevation of the groundwater level over time. Therefore, the foundation contractor should check the groundwater conditions just before foundation excavation activities. RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION Geotechnical Considerations Grading for the proposed addition was not available at the time of this report. However, we anticipate limited cuts and/or fill will be necessary. The Finished Floor Elevation (FFE) was also not available. Accordingly our recommendations are based on assuming a FFE at or near existing grade at the time of our field activities. If this information changes, we should be contacted to review and revise our recommendation as appropriate. The foundations being considered to provide support for the planned structure must satisfy two independent engineering criteria with respect to the subsurface conditions encountered at this site. One criterion is the foundation system must be designed with an appropriate factor of safety to reduce the possibility of a bearing capacity failure of the soils underlying the foundation. The other criterion is movement of the foundation system due to compression (consolidation or shrinkage) or expansion (swell) of the underlying soils must be within tolerable limits for the structure. The field and laboratory data acquired during this study indicate that the soils at this site have competent strength characteristics to support the proposed structure provided that the foundations are properly designed and constructed. The near surface (upper



2 feet) soils have a high potential to experience volumetric changes (swelling and shrinkage) with fluctuations in their moisture contents. We anticipate that the preferred foundation type for the structure is a slab-on-grade foundation. The suitability and performance of a soil supported foundation for a structure depends on many factors including the magnitude of soil movement expected, the type of structure, the intended use of the structure, the construction methods available to stabilize the soils, and our understanding of the owner’s expectations of the completed structure's performance. Based upon the results of our field and laboratory programs and using the Texas Department of Transportation (TxDOT) Method TEX-124-E, we estimate that the soils in the area of the borings exhibit a Potential Vertical Rise (PVR) about 1 to 1½ inch in its present condition. The majority of the PVR is due to the presence of Stratum I and II Expansive soils. The desired shallow slab-on-grade foundation system may be used at this site provided the pad and foundation are designed and constructed as recommended in this report. Due to the relative thin, two feet thick layer of expansive soil at this site and due to the fact that majority of this relative thin stratum will be removed during vegetation removal, it may seem prudent to remove all of this material within the building limits. Removing all of the expansive surface clay is described in the “Pad Preparation” section of this report and should result in a PVR of less than 1 inch. Pad Preparation We have provided the following subgrade preparation recommendations which are intended to reduce the magnitude of soil movements beneath the grade supported structures to less than 1 inch:

Strip any existing vegetation, loose topsoil and any other deleterious material from the building area. The building area is defined as the area that extends at least 3 feet beyond the perimeter of the slab, including any flatwork that abuts the structure such as sidewalks.

Excavate and remove the upper 2 feet thick of the on-site dark brown Stratum I

and Stratum II soil from the structure area to expose the Stratum III WEATHERED LIMESTONE.

Due to the possibility of void and caves features at this site; we recommend that the rock subgrade be thoroughly proofrolled as discussed above. if the exposed subgrade is MARL, After proofrolling, scarify and moisture condition the top 6 inches of the exposed MARL between -2 and +3 percentage points of the optimum moisture content. Compact the subgrade to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698.



Select fill then should be placed within the building area in order to achieve the finish floor elevation. Recommendations for the select fill are included in the “Select Fill Materials” section of this report. Maximum lift thickness should be 8 inches loose, to achieve about 6 inches compacted. Select fill soil should be moisture conditioned to between -2 and +3 percentage points of the optimum moisture content and compact the subgrade to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698.

To provide an “all-weather” working surface and to provide a more uniform slab

support, we recommend that the final 6 inches, or “cap” of the pad consist of granular select fill meeting the requirements given in the “Select Fill Materials” section of this report.

Preparing the building pad as discussed above would meet the requirements of Section 1805.8.3, Removal of Expansive Soils, of the 2006 International Building Code (IBC).

Slab Foundation A slab and grade beam foundation may be considered for this project. Parameters commonly used to design this type of foundation are provided in Table 1 at the end of this text. The slab foundation design parameters presented in Table 1 are based on the criteria published by the Prestressed Concrete Institute (PCI), the Building Research Advisory Board (BRAB) and the Post-Tensioning Institute (PTI 3rd Edition). These are essentially empirical design methods and the recommended design parameters are based on our understanding of the proposed project, our interpretation of the information and data collected as a part of this study, our area experience, and the criteria published in the PCI, BRAB, and PTI design manuals. We recommend that the grade beams be at least 24 inches below the FFE. These recommendations are for proper development of bearing capacity for the continuous beam sections of the foundation system and to reduce the potential for water to migrate beneath the slab foundation. These recommendations are not based on structural considerations. Grade beam depths may need to be greater than recommended herein for structural considerations and should be properly evaluated and designed by the Structural Engineer. The grade beams or slab portions may be thickened and widened to serve as spread footings at concentrated load areas. For a slab foundation system designed and constructed as recommended in this report, post construction settlements should be less than 1 inch. Settlement response of a select fill supported slab is influenced more by the quality of construction than by soil-structure interaction. Therefore, it is essential that the recommendations for foundation construction be strictly followed during the construction phases of the building pad and foundation.



Construction Considerations. Grade beams for the slab and footing foundations should preferably be neat excavated. Excavation should be accomplished with a smooth-mouthed bucket. If a toothed bucket is used, excavation with this bucket should be stopped 6 inches above final grade and the grade beam excavation completed with a smooth-mouthed bucket or by hand labor. If neat excavation is not possible then the foundation should be overexcavated and formed. All loose materials should be removed from the overexcavated areas and filled with lean concrete or compacted cement stabilized sand (two sacks cement to one cubic yard of sand) or flowable fill. Debris in the bottom of the excavation should be removed prior to steel placement. Rock drilling equipment may be required at this site.

Steel should be placed and the foundation poured the same day of excavation. If not, a seal slab consisting of lean concrete should be poured to protect the exposed foundation soils. The foundation excavations should be sloped sufficiently to create internal sumps for runoff collection and removal of water. If surface runoff water or subsurface water seepage in excess of 1 inch accumulates at the bottom of the foundation excavation, it should be collected and removed and not allowed to adversely affect the quality of the bearing surface. Special care should be taken to protect the exposed soils from being disturbed or drying out prior to placement of the concrete or the select fill pad. Spread Footings

Spread footings may also be used to support the planned structures. The individual footings should not bear shallower than 30 inches below the final grades and may bear in compacted fill or the Stratum III WEATHERED LIMESTONE. The footings should be designed for a total load net bearing pressure of 3,000 psf or a dead load net bearing pressure of 2,000 psf, whichever results in a larger bearing surface. These bearing pressures include a factor of safety of approximately 2 and 3, respectively. The spread footings can provide some uplift resistance for those structures subjected to wind or other induced structural loading. The uplift resistance of a spread footing may be computed using the effective weight of the soil above the spread footing along with the weight of the spread footing and structure. A soil unit weight of 100 pcf may be assumed for the on-site soils placed above the footing, provided the fill is properly compacted. These design soil criteria are for single, isolated spread footings. Footings on different levels should be placed such that a downward 1(V):2(H) projection from the leading edge of the upper footing passes below the adjacent, deeper foundation unit. All footings should be located such that their edge-to-edge spacing is at least 25 percent of the width of the largest footing involved. If a closer footing spacing is necessary, we should be contacted to evaluate if the single footing capacity is still valid or if a reduction in the single footing capacity is necessary due to the close foundation spacing. The final footing layout should be reviewed by the Geotechnical Engineer.



Settlements should be less than 1 inch for properly designed and installed spread footing foundations. Settlement of spread footings will be more sensitive to installation techniques than to soil-structure interaction.

Construction Considerations. Spread footing foundations should be neatly excavated.

Excavation should be accomplished with a smooth-mouthed bucket. If a toothed bucket is used, excavation with this bucket should be stopped 6 inches above the final bearing surface and the excavation completed with a smooth-mouthed bucket or by hand labor. If neat excavation is not possible then the foundation should be overexcavated and formed. All loose materials should be removed from the overexcavated areas and filled with lean concrete or compacted cement stabilized sand (two sacks cement to one cubic yard of sand) or flowable fill. Rock drilling equipment may be required at this site.

Steel and concrete for spread footings should be placed the same day of excavation. If not, a seal slab consisting of lean concrete should be constructed to protect the exposed foundation soils. The bearing surface should be excavated with a slight slope to create an internal sump for runoff water collection and removal. If surface runoff water accumulates at the bottom of the excavation, it should be pumped out prior to concrete placement. Under no circumstances should water be allowed to adversely affect the quality of the bearing surface. If the spread footing is buried, backfill above the foundation may be the excavated on-site soils or select fill soils. Backfill soils should be compacted to at least 95 percent of the maximum dry unit weight as determined by the standard moisture/density test (ASTM D 698) at moisture contents ranging from -2 to +3 percentage points of the optimum moisture content. The backfill should be placed in thin, loose lifts not to exceed 8 inches, with compacted thickness not to exceed 6. Drilled Pier Foundations As an alternative to shallow footings, drilled piers may be considered to support the proposed structure. Due to the presence of limestone, it is considered impractical to construct underreamed piers. Therefore, only straight-sided piers should be considered to support the buildings. Principal column loads for the buildings may be supported on straight-sided piers bearing at least of one pier diameter into natural Stratum III WEATHERED LIMESTONE and at least 10 feet below the FFE, whichever results in a deeper pier. The piers may be designed for a net allowable bearing pressure of 30,000 psf based on total load, or 20,000 psf based on dead load plus long-term live load, whichever results in a larger bearing surface. These bearing pressures include a factor of safety against a bearing capacity failure of approximately two and three, respectively. The above bearing pressures assume that the bearing surface will be free and clean of clay filled fractures or voids, soft or moist material, and loose debris. Piers should not extend deeper than 20 feet below the existing ground surface without contacting our office.



Used in conjunction with the end bearing values, an average allowable side shear value of 2,000 psf (with an assumed factor of safety of at least two) may be used in the natural rock for drilled pier design to aid in resisting axial compressive loads for the proposed structure. Due to the presence of highly weathered limestone and marl seams, the side-shear should be neglected for the upper 1 foot of rock, within one pier diameter of the shaft base, and for any portion of the shaft extending in select fill. Side shear should also be neglected for any clay layers greater than 6 inches in thickness encountered in the pier excavation. In addition to the axial compressive loads on the piers, these piers will also be subjected to axial tension loads due to swelling of the near surface clay soils and possibly due to other induced structural loading conditions. To compute the axial tension force due to the swelling soils along the pier shaft, the following equation may be used.

Qu = 10 ● d Where: Qu = Uplift force due to expansive soil conditions in kips (k) d = Diameter of pier shaft in feet (ft)

This calculated force can be used to compute the longitudinal reinforcing steel required in the pier to resist the uplift force induced by the swelling clays. However, the cross-sectional area of the reinforcing steel should not be less than ½ percent of the gross cross-sectional area of the drilled pier shaft. The reinforcing steel should extend from the top to the bottom of the shaft to resist this potential uplift force. The ultimate uplift resistance of the non-underreamed drilled piers can be evaluated using the following equation:

Qr = 7·π·d·Dp + Wp + PDL Where: Qr = Ultimate uplift resistance of pier in kips (k)

d = Diameter of pier shaft in feet (ft)

Dp = Length of pier shaft in contact with natural rock in feet (ft)

Wp = Weight of the drilled pier in kips (k)

PDL = Dead load acting on the drilled pier in kips (k) We recommend that a factor of safety of at least two be applied to the computed ultimate uplift force. For adjacent piers, we recommend a minimum edge-to-edge spacing of at least one pier diameter (or two pier diameters center-to-center) based on the larger diameter of the two adjacent piers. In locations where this minimum spacing criterion cannot be accomplished, Terracon should be contacted to evaluate the locations on a case-by-case basis.



Settlement Considerations. For piers, total settlements, based on the indicated bearing pressures, should be about 1 inch or less for properly designed and constructed drilled piers. Settlement beneath individual piers will be primarily elastic with most of the settlement occurring during construction. Differential settlement may also occur between adjacent piers. The amount of differential settlement could approach 50 to 75 percent of the total pier settlement. For properly designed and constructed piers, differential settlement between adjacent piers is estimated to be less than ¾ of an inch. Settlement response of drilled piers is impacted more by the quality of construction than by soil-structure interaction.

Improper pier installation could result in differential settlements significantly greater than we have estimated. In addition, larger magnitudes of settlement should be expected if the soil is subjected to bearing pressures higher than the allowable values presented in this report.

Construction Considerations. The pier excavations should be augered and constructed in a continuous manner. Steel and concrete should be placed in the pier excavations immediately following drilling and evaluation for proper bearing stratum, embedment, and cleanliness. In no circumstances should the pier excavations remain open overnight. Subsurface water was not encountered during or upon completion of the drilling. Subsurface water levels are affected by seasonal and climatic changes and may be present during periods of wet weather. Therefore, the contractor should be prepared to use temporary casing to reduce the water flow into the excavation and/or sloughing of the excavation sidewalls should this occur. The casing method is discussed in the following paragraphs. High torque “Rock” drilling equipment will be required at this site. Casing will provide stability of the excavation walls and will reduce water influx; however, casing may not completely eliminate subsurface water influx potential. In order for the casing to be effective, a “water tight” seal must be achieved between the casing and surrounding soils. The drilling subcontractor should determine casing depths and casing procedures. Water that accumulates in excess of 6 inches in the bottom of the pier excavation should be pumped out prior to steel and concrete placement. If the water is not pumped out, a closed-end tremie should be used to place the concrete completely to the bottom of the pier excavation in a controlled manner to effectively displace the water during concrete placement. If water is not a factor, concrete should be placed with a short tremie so the concrete is directed to the bottom of the pier excavation. The concrete should not be allowed to ricochet off the walls of the pier excavation nor off the reinforcing steel. If this operation is not successful or to the satisfaction of the foundation contractor, the pier excavation should be flooded with fresh water to offset the differential water pressure caused by the unbalanced water levels inside and outside of the casing. The concrete should be tremied completely to the bottom of the excavation with a closed-end tremie.



Removal of casing should be performed with extreme care and under proper supervision to minimize mixing of the surrounding soil and water with the fresh concrete. Rapid withdrawal of casing or the auger may develop suction that could cause the soil to intrude into the excavation. An insufficient head of concrete in the casing during its withdrawal could also allow the soils to intrude into the wet concrete. Both of these conditions may induce “necking”, a section of reduced diameter, in the pier. All aspects of concrete design and placement should comply with the American Concrete Institute (ACI) 318-99 Code Building Code Requirements for Structural Concrete, ACI 336.1-98 Standard Specification for the Construction of Drilled Piers, and ACI 336.3R-93 entitled Suggested Design and Construction Procedures for Pier Foundations. Concrete should be designed to achieve the specified minimum 28-day compressive strength when placed at a 7 inch slump with a ±1 inch tolerance. Adding water to a mix designed for a lower slump does not meet the intent of this recommendation. If a high range water reducer is used to achieve this slump, the span of slump retention for the specific admixture under consideration should be thoroughly investigated. Compatibility with other concrete admixtures should also be considered. A technical representative of the admixture supplier should be consulted on these matters. Successful installation of drilled piers is a coordinated effort involving the general contractor, design consultants, subcontractors, and suppliers. Each must be properly equipped and prepared to provide their services in a timely fashion. Several key items of major concern are:

Proper drilling rig with proper high power, high torque “Rock Drilling” equipment (including casing and augers).

Reinforcing steel cages tied to meet project specifications;

Proper scheduling and ordering of concrete for the piers; and

Monitoring of installation by design professionals.

Pier construction should be carefully monitored to assure compliance of construction activities with the appropriate specifications. A number of items of concern for pier installation include those listed below.

Pier locations Vertical alignment Competent bearing Casing removal (if needed)

Concrete properties and placement Steel placement Proper casing seal for subsurface water

control (if needed)



If the contractor has to deviate from the recommended foundations, Terracon should be notified immediately so additional engineering recommendations can be provided for an appropriate foundation type. Seismic Considerations

DESCRIPTION VALUE

2006 International Building Code Site Classification (IBC) 1 C2

Maximum Considered Earthquake 0.2 second Spectral (SS) Acceleration 0.09g

Maximum Considered Earthquake 1.0 second Spectral Acceleration (S1) 0.03g 1 The site class definition was determined using SPT N-values in conjunction with Table 1613.5.2 in

the 2006 IBC. The Spectral Acceleration values were determined using publicly available information provided on the United States Geological Survey (USGS) website. The above criteria can be used to determine the Seismic Design Category using Tables 1613.5.6 (1) and 1613.5.6 (2) in the 2006 IBC.

2 Note: The 2006 International Building Code (IBC) requires a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope does not include the required 100 foot soil profile determination. Borings extended to a maximum depth of 30 feet, and this seismic site class definition considers that similar soil continues below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration.

Interaction with Existing Structures The construction of additions to an existing structure can often create a situation that leads to the formation of distress in both structures if both structures are connected to each other. Typically, such distress occurs due to the use of different foundations and as a result of the structures having different framing stiffness. These differences often lead to dissimilar performances between the additions and existing structure. Such performance dissimilarities typically manifest themselves as differential movements and can cause significant amounts of distress. The risks associated with dissimilar performances between the additions and existing structure may be reduced by the following:

Design the foundation of the addition using the type and geometry similar to the existing foundation system (when appropriate);

Dowel the addition and existing foundations/floor slabs together to prevent

differential vertical movements across the joint; and

Construct an expansion joint between the new and existing structure to allow for differential horizontal movement between the addition and existing structure.

Excavating adjacent to the existing foundation should be performed with care. Excavations adjacent to the existing structure could cause the foundation to become undermined and the foundation or structure could suffer damages. We recommended that the contractor monitor the



existing foundation carefully during construction and be prepared to brace the existing foundation if necessary. Pavements Both flexible and rigid pavement systems may be considered for the project. Both “Light” and “Heavy” traffic loading conditions are also being considered for this project. For this project “Light” refers to general parking areas (automobile traffic) and “Heavy” refers to service area drives, main access drives and portions of the pavement subject to truck traffic. The flexible pavement section was designed using the National Asphalt Pavement Association (NAPA) Information Series (IS-109) method. The rigid pavement section was designed using the American Concrete Institute (ACI 330R-01) method. We can revise our pavement recommendations if different traffic information is provided to us.

FLEXIBLE PAVEMENT SYSTEM Material Thickness, inches

With Modified Subgrade

Without Modified Subgrade

Component Light Heavy Light Heavy Hot Mix Asphaltic Concrete Granular Base Material Modified Subgrade Moisture Conditioned Subgrade

2.0 6.0 6.0 ---

2.0 10.0 6.0 ---

2.0 10.0 --- 6.0

2.0 14.0 --- 6.0

Please note the following:

Asphaltic base material may be used in place of granular, unbound base material. Every 2 inches of granular base material may be replaced with 1 inch of asphaltic base material. The thickness of the asphaltic base material should be at least 4 inches.

We estimate a California Bearing Ratio (CBR) value of about 3 for design of asphaltic cement concrete pavement sections constructed on subgrades prepared as recommended in the “Earthwork Recommendations and Guidelines” section of this report. A modulus of subgrade

RIGID PAVEMENT SYSTEM Material Thickness, inches

With Modified Subgrade

Without Modified Subgrade

Component Light Heavy Light Heavy Reinforced Concrete Modified Subgrade Moisture Conditioned Subgrade

5.0 6.0 ---

6.0 6.0 ---

5.5 --- 6.0

6.5 --- 6.0



reaction (k) value of about 100 is estimated for design of Portland cement concrete pavement sections. Proper perimeter drainage is very important and should be provided so infiltration of surface water from unpaved areas surrounding the pavement is minimized. We do not recommend installation of landscape beds or islands in the pavement areas. Such features provide an avenue for water to enter into the pavement section and underlying soil subgrade. Water penetration usually results in degradation of the pavement section with time as vehicular traffic traverses the affected area. Above grade planter boxes, with drainage discharge onto the top of the pavement or directed into sewers, should be considered if landscape features are desired. Curbs should extend through the base and at least 3 inches below the base course. This will help reduce migration of subsurface water into the pavement base course from adjacent areas. A crack sealant compatible to both asphalt and concrete should be provided at all concrete-asphalt interfaces. Pavement areas that will be subjected to heavy wheel and traffic volumes, such as entrance/exit ramps, and delivery areas, should be a rigid pavement section constructed of reinforced concrete. The concrete pavement areas should be large enough to properly accommodate the vehicular traffic and loads. The pavement section has been designed using generally recognized structural coefficients for the pavement materials. These structural coefficients reflect the relative strength of the pavement materials and their contribution to the structural integrity of the pavement. If the pavement does not drain properly, it is likely that ponded water will infiltrate the pavement materials resulting in a weakening of the materials. As a result, the structural coefficients of the pavement materials will be reduced and the life and performance of the pavement will be shortened. The Asphalt Institute recommends a minimum of 2 percent slope for asphalt pavements. The importance of proper drainage cannot be overemphasized and should be thoroughly considered by the project team.

Pavement Section Materials. Presented below are selection and preparation guidelines for various materials that may be used to construct the pavement sections. Submittals should be made for each pavement material. The submittals should be reviewed by the Geotechnical Engineer and appropriate members of the design team and should provide test information necessary to verify full compliance with the recommended or specified material properties.

Hot Mix Asphaltic Concrete Surface Course - The asphaltic concrete surface course should be plant mixed, hot laid Type C or D Surface meeting the master specifications requirements of 2004 TxDOT Standard Specifications Item 340 and specific criteria for the job mix formula. The mix should be designed for a stability of at least 40 and should be compacted between 91 and 95 percent of the maximum theoretical density as measured by TEX-227-F. The asphalt cement content by percent of total mixture weight should fall within a tolerance of



±0.3 percent asphalt cement from the specific mix. In addition, the mix should be designed so 75 to 85 percent of the voids in the mineral aggregate (VMA) are filled with asphalt cement. The grade of the asphalt cement should be PG 64-22. Aggregates known to be prone to stripping should not be used in the hot mix. If such aggregates are used measures should be taken to mitigate this concern. The mix should have at least 70 percent strength retention when tested in accordance with Tex-531-C. 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 pavement specimens may be used when approved by the Engineer. Unless otherwise shown on the plans, the Contractor shall be responsible for obtaining the required pavement specimens at their expense and in a manner and at locations selected by the Engineer. Concrete - Concrete should have a minimum 28-day design compressive strength of 4,000 psi. Granular Base Material - Base material may be composed of crushed limestone base meeting all of the requirements of 2004 TxDOT Item 247, Type A, Grade 1 or 2; and should have no more than 15 percent of the material passing the No. 200 sieve. The base should be compacted to at least 95 percent of the maximum dry density as determined by the modified moisture-density relation (ASTM D 1557) at moisture contents ranging between -2 and +3 percentage points of the optimum moisture content. Asphaltic Base Course - The asphaltic base material should meet the specification requirements of 2004 TxDOT Standard Specification Item 340, Type A or B or item 292, Grade 1. Modified Subgrade – The subgrade may be treated with hydrated lime in accordance with 2004 TxDOT Items 260 in order to reduce its plasticity, improve its strength and improve its load carrying capacity. If used, the quantity of lime required should be determined after the site is stripped of the loose topsoil and the subgrade soils are exposed. We anticipate that approximately 6 percent hydrated lime will be required. This is equivalent to about 27 pounds of hydrated lime per square yard for a 4 inch treatment depth. However, the actual percentage should be determined by laboratory tests on samples of the clayey subgrade prior to construction. The optimum lime content should result in a soil-lime mixture with a pH of at least 12.4 when tested in accordance with ASTM C 977, Appendix XI and should reduce the PI to 20 percent or less.



The lime should initially be blended with a mixing device such as a Pulvermixer, sufficient water added, and be allowed to cure for at least 48 hours. After curing, the lime-soil should be remixed to meet the in-place gradation requirements of Item 260 and compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698 at moisture contents ranging from optimum to +4 percentage points of the optimum moisture content. If the in-place gradation requirements can be achieved during initial mixing, the remixing after the curing period can be eliminated. Please note that there is a relationship between the time of mixing of the lime and soils with the maximum dry density. The maximum dry density decreases with time, therefore, any mixture older than 3 days will require a new set of compaction curves. Moisture Conditioned Subgrade - The subgrade should be scarified to a depth of 6 inches and moisture conditioned between optimum and +4 percentage points of the optimum moisture content. The subgrade should then be compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698.

Details regarding subgrade preparation and fill placement and compaction are presented in the subsection titled “Earthwork.”

Pavement Joints and Reinforcement. The following is recommended for all concrete pavement sections in this report. Refer to ACI 330 “Guide for Design and Construction of Concrete Parking Lots” for additional information. Contraction Joint Spacing: Contraction joints should be spaced 12½ feet each way for

pavement thickness of 5 inches; 15 feet each way for pavement thickness of 6 inches or greater.

Contraction Joint Depth: At least ¼ of pavement thickness. Contraction Joint Width: One-fourth inch or as required by joint sealant

manufacturer. Construction Joint Spacing: To attempt to limit the quantity of joints in the pavement,

consideration can be given to installing construction joints at contraction joint locations, where it is applicable.

Construction Joint Depth/ Width: Full depth of pavement thickness. Construct sealant

reservoir along one edge of the joint. Width of reservoir to be ¼ inch or as required by joint sealant manufacturer. Depth of reservoir to be at least ¼ of pavement thickness.



Isolation Joint Spacing: As required to isolate pavement from structures, etc. Isolation Joint Depth: Full depth of pavement thickness. Isolation Joint Width: One-half to 1 inch or as required by the joint sealant

manufacturer.

Expansion Joint: None (see note below)

Note: In this locale, drying shrinkage of concrete typically significantly exceeds anticipated expansion due to thermal affects. As a result, the need for expansion joints is eliminated provided all joints (including saw cuts) are sealed. Construction of an unnecessary joint may be also become a maintenance problem. All joints should be sealed. If all joints, including sawcuts, are not sealed then expansion joints should be installed.

Distributed Steel: Steel reinforcement may consist of steel bars described as follows:

No 3 reinforcing steel bars at 12 inches on center each way, Grade 60; or No 4 reinforcing steel bars at 18 inches on center each way, Grade 60

Note: It is imperative that the distributed steel be positioned accurately in the pavement

cross section. All construction joints have dowels. Dowel information varies with pavement thickness as presented as follows.

Pavement Thickness: 5,5.5 inches 6,6.5 inches Dowels: ⅝ inch diameter ¾ inch diameter Dowel Spacing: 12 inches on center 12 inches on center Dowel Length: 12 inches long 14 inches long Dowel Embedment: 5 inches 6 inches

Details about subgrade preparation and fill placement and compaction are presented in the following subsection. Earthwork The comments and suggestions in this section are provided for planning and informational purposes so project specifications can be prepared and to indicate conventional methods to achieve the intent of our design recommendations. Details regarding excavation, dewatering, selection of equipment/machinery, trafficability, project site safety, shoring, and other similar construction techniques that require “means and methods” to accomplish the work is the sole responsibility of the project contractor. It should be recognized that the comments contained in



this report are based on the observations of small diameter boreholes and the performance of larger excavations may differ significantly as a result of the differences in excavation sizes. Construction means and methods selected by the contractor may differ from those described in this report. Any variations may significantly impact the anticipated behavior of the subsurface conditions during the construction process.

Site Access. Proper site drainage should be maintained during the entire construction

phase so ponding of surface runoff does not occur and cause construction delays and/or inhibit site access, particularly in cut areas. During construction, it is possible the surficial soils may become excessively wet as a result of inclement weather conditions. When the moisture content of these soils elevates above what is considered to be the optimum range of moisture for compaction operations, they can become difficult to handle and compact. If such conditions create a hindrance to compaction operations or site access, hydrated lime may be mixed with these soils to improve their workability. The modifier can be mixed in general accordance with TxDOT Item 260. However, the purpose of the modifier is to dry out the subgrade and allow site workability. The strict requirements for curing and the actual modifier percentage can and should be at the discretion of the contractor. The modified subgrade, however, should be compacted to at least 95 percent of the maximum dry density as evaluated by ASTM D 698 at moisture contents between optimum and +4 percentage points of the optimum moisture content.

Building and Pavement Subgrade Preparation. Subgrade preparation and earthwork

in the building area should be performed in accordance with the recommendations given in the “Pad Preparation” section of this report. Existing vegetation, loose topsoil any other deleterious material should be removed from the building areas. Subgrade preparation should extend at least 3 feet beyond the horizontal limits of the pavements and building (including all abutting sidewalks and other flatwork).

After site stripping and excavating operations, the exposed subgrade should be proofrolled with appropriate construction equipment weighing at least 20 tons. The purpose of this recommendation is to check the subgrade for weak/soft zones prior to fill or base placement and compaction. This operation should be observed and evaluated by Terracon’s qualified geotechnical personnel experienced in earthwork operations. If weak or soft zones are evidenced during proofrolling operations, the weak material in the subject area should be removed to expose competent subgrade soils in both the horizontal and vertical limits. The select fill can be reused to restore grade at these isolated areas. The select fill soil should be placed in loose lifts of no more than 8 inches, be moisture conditioned between -2 and +3 percentage points of the optimum moisture content, and then compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698. Pavement subgrade areas requiring fill placement should be placed in loose lifts of no more than 8 inches, be moisture conditioned between optimum and +4 percentage points of the optimum moisture content, and then compacted to at least 95 percent of the maximum dry



density determined in accordance with ASTM D 698. Subgrade areas should be moisture conditioned and compacted just prior to fill or base placement so the subgrade maintains its compaction moisture levels and does not dry out.

Select Fill Materials. Grade adjustments for this project should be accomplished with non-expansive (inert) select fill materials such as a low plasticity clayey soil, clayey gravel, crushed stone base material or crushed concrete. All select fill soils should have a PI between 7 and 15 percent. The select fill materials should be relatively free of organic material and debris, and should not contain stones larger than 3 inches in maximum dimension. For building pad construction, granular select fill should consist of 2004 TxDOT Item 247, Type A or B, Grade 1 or 2 crushed limestone or gravel base material. Granular select fill can also consist of crushed concrete meeting the criteria specified in the 2004 TxDOT Item 247, Type D, Grade 1 or 2. It should be noted that gradation requirements for a Grade 1 or 2 materials are much more stringent than for a non-processed select fill. As a result, the stability of a non-processed material may be significantly less than that of a Grade 1 or 2 materials, especially in an unconfined condition. Therefore, the use of a non-processed material may result in more sloughing of the fill during trenching or excavations that may be necessary for utility “rough-in” and foundation installation. Additionally, a Grade 1 or 2 materials is generally more resistant to the effects of hard rain during construction than a non-processed material. Select fill should be placed in loose lifts of no more than 8 inches, be moisture conditioned between -2 and +3 percentage points of the optimum moisture content, and then compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698.

Preconstruction Meeting. Every project and construction site is unique, making it vitally important that all construction drawings, specifications, change orders, and related documents be reviewed by the respective design professionals participating in the project. The performance of the foundations for this project will depend on correct interpretation of our geotechnical engineering report and proper compliance of construction activities with regard to our geotechnical recommendations and to the construction drawings and specifications. We highly recommend that a preconstruction meeting be conducted. One of the purposes of the meeting is to discuss the Special Inspections required on the plan documents. The following are among those that should be discussed at the meeting:

Lines of Communication/Authority;

Reporting (both verbal and written); and

Special Inspections. In particular; what is required; who will perform the inspections; what are the specified frequencies; how should the inspections be scheduled; and, reporting requirements.



GENERAL COMMENTS Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project. The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated location and from other information discussed in this report. This report does not reflect variations that may occur away from our borings, across the site, or due to the modifying effects of weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be immediately notified so that further evaluation and supplemental recommendations can be provided.

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

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.


TABLE


Reliable ■ Responsive ■ Convenient ■ Innovative

TABLE 1 SLAB FOUNDATION DESIGN PARAMETERS

CROSSPOINT FELLOWSHIP CHURCH ADDITIONS SCHERTZ, TEXAS

CONVENTIONAL METHOD PREPARED SUBGRADE 1

Net Allowable Bearing Pressures 2

Total Load 3,000 psf

Dead Load 2,000 psf

Subgrade Modulus (k) 100 pci

Potential Vertical Rise (PVR) Less than 1 inch

BRAB/PCI METHODS

Design Plasticity Index (PI) 3 19

Climatic Rating (Cw) 17

Unconfined Compressive Strength 1.0 tsf

Soil Support Index (C) 0.96

PTI METHOD 3RD EDITION

Thornthwaite Moisture Index (Im) -13

Depth of Constant Soil Suction 7 feet

Constant Soil Suction 3.6 pF

Net Allowable Bearing Pressures 2

Total Load 3,000 psf

Dead Load 2,000 psf

Edge Moisture Variation Distance (em):

Center Lift 9.0 feet

Edge Lift 5.0 feet

Differential Soil Movement (ym):

Center Lift 0.6 inches

Edge Lift 1.0 inches

Coefficient of Slab-Subgrade Friction (μ): 0.75 to 1.00 1 Based on preparing the building pad as discussed in this report.

2 The net allowable bearing pressures provided above include a factor of safety of at least 2 and 3, respectively.

3 The BRAB effective PI is equal to the near surface PI if that PI is greater than all of the PI values in the upper 15 feet. The PCI effective PI is always the weighted average of the PI values in the upper 15 feet.


APPENDIX A

FIELD EXPLORATION

Vicinity Map Bore Location Plan

Boring Log Field Exploration Description

2.5

22.0

25.0

STRATUM ISANDY FAT CLAY; dark brown, graveland rootsSTRATUM IIIWEATHERED LIMESTONE; white to lighttan, interbedded marl layers

STRATUM IVMARL; light tan

Boring Terminated at about 25 feet.

39 57

21

SS

SS

SS

SS

SS

SS

SS

SS

24N=15

N=50/4"

N=ref/3"

N=50/4"

N=ref/0"

N=ref/0"

N=ref/0"

N=ref/5"

31

4

3

4

4

5

5

26

63

Approx. Surface Elevation: Existing GradeGra

phic

Log DESCRIPTION

FIGURE NO.3

See Bore Location Plan

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FREE WATER WAS NOT OBSERVED DURING OURDRILLING OPERATIONS

Crosspoint Fellowship ChurchSchertz, Texas

PROJECT NUMBER

90095129

LOG OF BORING NO. B-1

BORINGLOCATION:

Remarks - The boring was backfilled with cuttings after completion of the subsurfacewater level observations.

STRATIFICATION LINES REPRESENT APPROXIMATEBOUNDARIES BETWEEN SOIL TYPES. IN SITU, THETRANSITION BETWEEN STRATA MAY BE MOREGRADUAL.

CLIENT:

WATER LEVEL OBSERVATIONS

US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %

Schertz, TexasSAMPLES

5

10

15

20

25

PLA

STI

C L

IMIT

, %

Crosspoint Fellowship Church Additions

LIQ

UID

LIM

IT, %

2600 Roy Richards Road

TYP

E

MO

ISTU

RE

CO

NTE

NT,

%

2.0

30.0



38

8

60SS

SS

SS

SS

SS

SS

SS

SS

SS

27

19

N=17

N=58

N=55

N=ref/5"

N=50/5"

N=ref/0"

N=ref/0"

N=ref/0"

N=ref/0"

24

5

5

5

15

5

6

10

8

65

27


phic

Log DESCRIPTION

FIGURE NO.4


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PROJECT NUMBER

90095129


BORINGLOCATION:



CLIENT:


US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %


5

10

15

20

25

30

PLA

STI

C L

IMIT

, %


LIQ

UID

LIM

IT, %


TYP

E

MO

ISTU

RE

CO

NTE

NT,

%

2.0

22.0

30.0




36 55

22

63

SS

SS

SS

SS

SS

SS

SS

SS

SS

25N=28

N=46

N=50/4"

N=ref/0"

N=ref/4"

N=ref/0"

N=ref/0"

N=ref/4"

N=ref/0"

21

6

4

4

4

3

3

25

5

61


phic

Log DESCRIPTION

FIGURE NO.5


DATE DRILLED

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PROJECT NUMBER

90095129


BORINGLOCATION:



CLIENT:


US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %


5

10

15

20

25

30

PLA

STI

C L

IMIT

, %


LIQ

UID

LIM

IT, %


TYP

E

MO

ISTU

RE

CO

NTE

NT,

%

2.5

23.0

25.0

STRATUM IISANDY LEAN CLAY; dark brown, graveland rootsSTRATUM IIIWEATHERED LIMESTONE; white to lighttan, interbedded marl layers



22 47

35

SS

SS

SS

SS

SS

SS

SS

SS

19N=10

N=36

N=ref/3"

N=ref/5"

N=ref/0"

N=ref/0"

N=ref/0"

N=ref/4"

17

13

2

4

2

3

5

26

41


phic

Log DESCRIPTION

FIGURE NO.6


DATE DRILLED

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PROJECT NUMBER

90095129


BORINGLOCATION:



CLIENT:


US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %


5

10

15

20

25

PLA

STI

C L

IMIT

, %


LIQ

UID

LIM

IT, %


TYP

E

MO

ISTU

RE

CO

NTE

NT,

%

2.0

5.0

STRATUM IISANDY LEAN CLAY; dark brown, graveland rootsSTRATUM IIIWEATHERED LIMESTONE; white to lighttan, interbedded marl layers


24 38

49

SS

SS

SS

24N=34

N=61

N=81/6"

20

5

4

48


phic

Log DESCRIPTION

FIGURE NO.7


DATE DRILLED

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PROJECT NUMBER

90095129


BORINGLOCATION:



CLIENT:


US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %


5

PLA

STI

C L

IMIT

, %


LIQ

UID

LIM

IT, %


TYP

E

MO

ISTU

RE

CO

NTE

NT,

%

2.0

5.0



31

48

SS

SS

SS

27N=24

N=69

N=ref/4"

27

4

4

58


phic

Log DESCRIPTION

FIGURE NO.8


DATE DRILLED

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PROJECT NUMBER

90095129


BORINGLOCATION:



CLIENT:


US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %


5

PLA

STI

C L

IMIT

, %


LIQ

UID

LIM

IT, %


TYP

E

MO

ISTU

RE

CO

NTE

NT,

%

2.0

5.0



29 39

87

SS

SS

SS

24N=16

N=64

N=ref/5"

24

5

6

53


phic

Log DESCRIPTION

FIGURE NO.9


DATE DRILLED

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PROJECT NUMBER

90095129


BORINGLOCATION:



CLIENT:


US

CS

SY

MB

OL

PLA

STI

CIT

Y IN

DE

X

CO

MP

RE

SS

IVE

STR

EN

GTH

, TS

F

DE

PTH

, FE

ET

SITE:

PROJECT:

FAIL

UR

E S

TRA

IN, %

CO

NFI

NIN

GP

RE

SS

UR

E, P

SI

N: B

LOW

S/F

TP

: TO

NS

/SQ

FT

T: T

ON

S/S

Q F

T

TESTS

DR

Y D

EN

SIT

Y, P

CF

MIN

US

#20

0S

IEV

E, %


5

PLA

STI

C L

IMIT

, %


LIQ

UID

LIM

IT, %


TYP

E

MO

ISTU

RE

CO

NTE

NT,

%



Field Exploration Description Terracon personnel used the site plan provided by Shanks Architects to establish the bore locations in the field. Location of the boring is shown on the attached “Bore Location Plan.” A truck-mounted, rotary drill rig equipped with continuous flight augers and air rotary was used to advance the boreholes. Soil samples were obtained by split-barrel sampling procedures. In the split-barrel sampling procedure, a standard 2-inch O.D. split-barrel sampling spoon is driven into the ground with a 140-pound hammer falling a distance of 30 inches. The number of blows required to advance the sampling spoon the last 12 inches of a normal 18-inch penetration is recorded as the standard penetration resistance value. These values are indicated on the borings logs at the depths of occurrence. The samples were sealed and transported to the laboratory for testing and classification. Our field representative prepared the field logs as part of the drilling operations. The boring logs included visual classifications of the materials encountered during drilling and our field representative interpretation of the subsurface conditions between samples. Each boring log included with this report represents the engineer’s/geologist’s interpretation of the field logs and include modifications based on visual observations and testing of the samples in the laboratory. The scope of services for our geotechnical engineering services does not include addressing any environmental issues pertinent to the site.


APPENDIX B

LABORATORY TESTING



Laboratory Testing Samples retrieved during the field exploration were taken to the laboratory for further observation by the project geotechnical engineer and were classified in accordance with the Unified Soil Classification System (USCS) described in Appendix C. At that time, the field descriptions were confirmed or modified as necessary and an applicable laboratory testing program was formulated to determine engineering properties of the subsurface materials. Laboratory tests were conducted on selected soil samples and the test results are presented in this appendix. The laboratory test results were used for the geotechnical engineering analyses, and the development of foundation and earthwork recommendations. Laboratory tests were performed in general accordance with the applicable ASTM, local or other accepted standards. Selected soil samples obtained from the site were tested for the following engineering properties:

In-situ Water Content Atterberg Limits Amount of Material In-Soil Finer than the No 200 Mesh (75-µm) Sieve

Sample Disposal All samples were returned to our laboratory. The samples not tested in the laboratory will be stored for a period of 30 days subsequent to submittal of this report and will be discarded after this period, unless other arrangements are made prior to the disposal period.


APPENDIX C

SUPPORTING DOCUMENTS

General Notes Unified Soil Classification System

ASFE Information

GENERAL NOTES DRILLING & SAMPLING SYMBOLS: SS: Split Spoon - 1-3/8" I.D., 2" O.D., unless otherwise noted HS: Hollow Stem Auger ST: Thin-Walled Tube - 2" O.D., unless otherwise noted PA: Power Auger RS: Ring Sampler - 2.42" I.D., 3" O.D., unless otherwise noted HA: Hand Auger DB: Diamond Bit Coring - 4", N, B RB: Rock Bit BS: Bulk Sample or Auger Sample WB: Wash Boring or Mud Rotary

The number of blows required to advance a standard 2-inch O.D. split-spoon sampler (SS) the last 12 inches of the total 18-inch penetration with a 140-pound hammer falling 30 inches is considered the “Standard Penetration” or “N-value”.

WATER LEVEL MEASUREMENT SYMBOLS: WL: Water Level WS: While Sampling N/E: Not Encountered WCI: Wet Cave in WD: While Drilling DCI: Dry Cave in BCR: Before Casing Removal AB: After Boring ACR: After Casing Removal

Water levels indicated on the boring logs are the levels measured in the borings at the times indicated. Groundwater levels at other times and other locations across the site could vary. In pervious soils, the indicated levels may reflect the location of groundwater. In low permeability soils, the accurate determination of groundwater levels may not be possible with only short-term observations.

DESCRIPTIVE SOIL CLASSIFICATION: Soil classification is based on the Unified Classification System. Coarse Grained Soils have more than 50% of their dry weight retained on a #200 sieve; their principal descriptors are: boulders, cobbles, gravel or sand. Fine Grained Soils have less than 50% of their dry weight retained on a #200 sieve; they are principally described as clays if they are plastic, and silts if they are slightly plastic or non-plastic. Major constituents may be added as modifiers and minor constituents may be added according to the relative proportions based on grain size. In addition to gradation, coarse-grained soils are defined on the basis of their in-place relative density and fine-grained soils on the basis of their consistency.

CONSISTENCY OF FINE-GRAINED SOILS RELATIVE DENSITY OF COARSE-GRAINED SOILS

Unconfined

Compressive Strength, Qu, psf

Standard Penetration or N-value (SS)

Blows/Ft.

Consistency

Standard Penetration

or N-value (SS) Blows/Ft.

Relative Density < 500 <2 Very Soft 0 – 3 Very Loose 500 – 1,000 2-3 Soft 4 – 9 Loose 1,001 – 2,000 4-6 Medium Stiff 10 – 29 Medium Dense 2,001 – 4,000 7-12 Stiff 30 – 49 Dense 4,001 – 8,000 13-26 Very Stiff 50+ Very Dense 8,000+ 26+ Hard

RELATIVE PROPORTIONS OF SAND AND GRAVEL GRAIN SIZE TERMINOLOGY Descriptive Term(s) of other

constituents Percent of Dry Weight

Major Component of Sample

Particle Size

Trace < 15 Boulders Over 12 in. (300mm) With 15 – 29 Cobbles 12 in. to 3 in. (300mm to 75 mm)

Modifier > 30 Gravel 3 in. to #4 sieve (75mm to 4.75 mm)

RELATIVE PROPORTIONS OF FINES Sand

Silt or Clay #4 to #200 sieve (4.75mm to 0.075mm)

Passing #200 Sieve (0.075mm)

PLASTICITY DESCRIPTION Descriptive Term(s) of other constituents

Percent of Dry Weight

Term Plasticity Index

Trace With

Modifiers

< 5 5 – 12 > 12

Non-plastic

Low Medium

High

0 1-10 11-30 30+

Form 111—6/98

UNIFIED SOIL CLASSIFICATION SYSTEM Criteria for Assigning Group Symbols and Group Names Using Laboratory TestsA Soil Classification

Group Symbol

Group NameB

Cu ≥ 4 and 1 ≤ Cc ≤ 3E GW Well-graded gravelF Clean Gravels Less than 5% finesC Cu < 4 and/or 1 > Cc > 3E GP Poorly graded gravelF

Fines classify as ML or MH GM Silty gravelF,G, H

Coarse Grained Soils

More than 50% retained

on No. 200 sieve

Gravels More than 50% of coarse fraction retained on No. 4 sieve Gravels with Fines More

than 12% finesC Fines classify as CL or CH GC Clayey gravelF,G,H

Cu ≥ 6 and 1 ≤ Cc ≤ 3E SW Well-graded sandI Clean Sands Less than 5% finesD Cu < 6 and/or 1 > Cc > 3E SP Poorly graded sandI

Fines classify as ML or MH SM Silty sandG,H,I

Sands 50% or more of coarse fraction passes No. 4 sieve Sands with Fines

More than 12% finesD Fines Classify as CL or CH SC Clayey sandG,H,I

PI > 7 and plots on or above “A” lineJ CL Lean clayK,L,M Silts and Clays Liquid limit less than 50

inorganic

PI < 4 or plots below “A” lineJ ML SiltK,L,M

Liquid limit - oven dried Organic clayK,L,M,N

Fine-Grained Soils 50% or more passes the No. 200 sieve

organic

Liquid limit - not dried < 0.75 OL

Organic siltK,L,M,O

inorganic PI plots on or above “A” line CH Fat clayK,L,M

Silts and Clays Liquid limit 50 or more

PI plots below “A” line MH Elastic SiltK,L,M

Liquid limit - oven dried Organic clayK,L,M,P organic

Liquid limit - not dried < 0.75 OH

Organic siltK,L,M,Q

Highly organic soils Primarily organic matter, dark in color, and organic odor PT Peat

A Based on the material passing the 3-in. (75-mm) sieve B If field sample contained cobbles or boulders, or both, add “with cobbles

or boulders, or both” to group name. C Gravels with 5 to 12% fines require dual symbols: GW-GM well-graded

gravel with silt, GW-GC well-graded gravel with clay, GP-GM poorly graded gravel with silt, GP-GC poorly graded gravel with clay.

D Sands with 5 to 12% fines require dual symbols: SW-SM well-graded sand with silt, SW-SC well-graded sand with clay, SP-SM poorly graded sand with silt, SP-SC poorly graded sand with clay

E Cu = D60/D10 Cc = 6010

230

DxD)(D

F If soil contains ≥ 15% sand, add “with sand” to group name. G If fines classify as CL-ML, use dual symbol GC-GM, or SC-SM.

HIf fines are organic, add “with organic fines” to group name. I If soil contains ≥ 15% gravel, add “with gravel” to group name. J If Atterberg limits plot in shaded area, soil is a CL-ML, silty clay. K If soil contains 15 to 29% plus No. 200, add “with sand” or “with

gravel,” whichever is predominant. L If soil contains ≥ 30% plus No. 200 predominantly sand, add

“sandy” to group name. M If soil contains ≥ 30% plus No. 200, predominantly gravel, add

“gravelly” to group name. N PI ≥ 4 and plots on or above “A” line. O PI < 4 or plots below “A” line. P PI plots on or above “A” line. Q PI plots below “A” line.

geotechnical engineering report - timbercon

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