Loading...
CiCi's Addition-SY080806(8/3112009) DiWanna Baskins - rp1543101.pdf PROJECT N0.15431 MAY, 2008 GEOTECHNICAL INVESTIGATION CICI'S PIZZA DISTRIBUTION ADDITION BETHEL ROAD COPPELL, TEXAS Presented Ta: ELEMENTS OF ARCHITECTURE, INC. FORT WORTH, TEXAS Page (8/3112009) DiWanna Baskins - rp1543101.pdf I~EE^ E~IGlf~IEEF~IrIG GEOTECHNICAL AND G R ^ U P ENVIRONMENTAL CONSULTANTS May 12, 2008 Project No. 15431 Elements~of Architecture, lnc. 500 W. 7 Street, Suite 502 Fort Worth, Texas 76102 ATTN: Mr. Dallas Proctor, AlA GEOTECHNICAL INVESTIGATION CICI'S PIZZA DISTRIBUTION ADDITION BETHEL ROAD COPPELL, TEXAS Gentlemen: Transmitted herewith are copies of the referenced report. Should you have any questions concerning our findings or if you desire additional information, do not hesitate to call. Sincerely, • e • ~ /~ • • ~.i ' ~ ' ~~~~~~r~~~~s^~~~~~~~~ ~ R~QNA~.D F REED, RE. i • s Ronald F. Reed, P.E. ~~~ ~ ~ ~ ~ ,481~74~ ~ ~ ~ ~~~ . ~ ~ • ~ ' '~ 1,~ •.( 5 0;• ~ ~ / ~ DGW/RFR/apv ~ ~ ~,~~.''~EN, ~~'~~~~' ~~ ~``~NA` ~~= ~~. copies submitted: (3} Page 2 2424 STUTZ DRIVE, SUITE 400 DALLAS,TX 75235 GEOTECHNICAL ENGINEERING tel 214.350.5b00 fax 214.350.0019 ENVIRONMENTAL CONSULTING www.reed-engineering.com CONSTRUCTION MATERIALS TESTING (8/3112009) DiWanna Baskins - rp1543101.pdf TABLE OF CONTENTS PAGE INTRODUCTION .. . . . ............................. . ............................................................... l Project Description ...................................................................................... i Autharization ............................................................................................... 1 Purpose and Scope ....................................................................................... l FIELD AND LABORATORY INVESTIGATIONS ........................................... 2 General .......................................................................................................... 2 Field Investigation ....................................................................................... 2 Laboratory Testing ...................................................................................... 3 GENERAL SITE CONDITIONS ...........................................................................4 Geology and Stratigraphy ...........................................................................4 Ground Water .............................................................................................. 5 Texas Health and Safety Cade and TCEQ Comment .............................. 5 Seismic Site Classification ........................................................................... b ANALYSIS AND RECOMMENDATIONS ..........................................................6 Potential Vertical Movements ..................................................................... b Foundation Type, Depth and Allowable Loading ................................... 7 Grade BeamslTilt-Wall Panels ...................................................................10 Floor Slab ..................................................................................................... 11 Retaining Walls ............................................................................................ 20 Earthwork .................................................................................................... 22 Pavement ..................................... . ................................................................. 24 Pavement Joints ........................................................................................... 29 Construction Observation and Testing Frequency .................................. 32 Page 3 i- (8/3112009) DiWanna Baskins - rp1543101.pdf TABLE OF CONTENTS (Continued) ILLUSTRATIONS PLATE PLAN OF BORINGS .............................................................................................. 1 BORING LOGS ...................................................................................................... 2-S KEYS TO TERMS AND SYMBOLS USED ........................................................ 6&7 LABORATORY TEST RESULTS ........................................................................ 8&9 ABSORPTION PRESSURE-SWELL TEST RESULTS .....................................10 SPECIFICATIONS PAGE WATER INJECTION WI"SELECT" FILL CAP ............................................... 1 WATER INJECTION WILIME-MODIFIED CAP ............................................. ~ Page 4 -ii- (8/3112009) DiWanna Baskins - rp1543101.pdf INTRODUCTION Project Description This report presents the results of a geotechnical investigation performed for an addition to the Cici's Pizza Distribution building on Bethel Raad in Coppell, Texas. The general orientation of the existing building and addition is shown an the Plan of Borings, Plate 1 of the report Illustrations. The project consists of a 150-foot by 42-foot addition north of the existing building. Finished floor has been set at 545.0 to match the existing finished floor. Authorization This investigation was authorized by signature of our Proposal No. 4-28 an April 16, 2008. Purpose and Scope The purpose of this investigation has been to evaluate the general subsurface conditions and provide recommendations for: • design of the foundation system; • floor slab; • below-grade and retaining walls; • pavement subgrade; and • site preparation and earthwork compaction criteria. The investigation has included drilling sample borings, performing laboratory testing, analyzing engineering and geologic data and developing geotechnical recommendations. The fallowing sections present the methodology used in this investigation. Page 5 Project No.15431 -1 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Recommendations provided herein are site-specific and were developed for the project discussed in the report Introduction. Persons using this report for other than the intended purpose do so at their own risk. FIELD AND LABORATORY INVESTIGATIONS General The field and laboratory investigations have been conducted in accordance with applicable standards and procedures set forth in the 2007 Annual Baok of ASTM Standards, Volumes 04.08 and 04.09, "Soil and Rock.'" These volumes should be consulted for information on specific test procedures. Field Investigation Subsurface conditions were evaluated by four sample borings drilled to depths of b to 27 feet in April 2x08. The locations of the borings are shown on Plate 1 of the report Illustrations. Borings were advanced between sampling intervals by means of atruck-mounted drilling rig equipped with continuous flight augers. Samples of cohesive soils were obtained with 3-inch diameter Shelby tubes (ASTM D 1587). Unweathered shale was evaluated in-situ using the Texas Department of Transportation (TxDOT) cone penetrometer test. Delayed water level observations were made in the open boreholes to evaluate ground water conditions. The borings were backfilled at completion of field operations. Page 6 Project No.15431 - 2 - May 12, 2008 8/3112009) DiWanna Baskins - rp1543101.pdf Page (8/3112009) DiWanna Baskins - rp1543101.pdf TABLE ~ TESTS CONDUCTED AND ASTM DESIGNATIONS Continued) Type of Test ASTM Designation Soil Suction D 529$ Unconfined Compression (Soil) D 216G The results of these tests are summarized on Plates 8 and 9. The expansive characteristics ofthe severely weathered shale were also evaluated by means of a single absorption pressure-swell test conducted in accordance with general procedures discussed by Johnson and Snethenl. Results of the swell test are presented graphically on Plate 10. GENERAL SITE CONDITIONS Geology and Stratigraphy Subsurface conditions encountered in the borings consist of alluvial soils over severely weathered grading to unweathered shale of the Cretaceous Eagle Ford Formation. The alluvial soils consisted of 2-112 to 5-112 feet of dark brown to brawn to grayish-brown, high plasticity (CH) clay. Below the alluvial clay, olive-yellow to yellowish-brown and pale brown, severely ~ Johnson, L.D., & Snethen, D.R. (1978). "Prediction of Potential Heave of Swelling Soil." Geotechnical Testing Journal, ASTM 1 (3), 117-124. Page 8 Project Na.15431 - 4 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf weathered shale and silty shale was encountered. The severely weathered shale and silty shale possesses the engineering properties of CH clay and silty clay. The alluvial clays and severely weathered shale and silty shale were hard to stiff at the time of the investigation. Below depths of 20 to 22 feet, dark gray, soft (rock classification}, weathered shale was encountered. The weathered shale contained iron stains and iron-stained laminations. The weathered shale graded into dark gray, unweathered shale below depths of 21-112 to 23-112 feet (Elev. 519.5 to 518.5}. The unweathered shale was encountered through the termination depths of both of the deeper borings. Ground Water Ground water seepage was encountered during drilling in one baring at a depth of 14 feet. Ground water was encountered in both of the deeper borings at depths of 9 to 16 feet approximately three days following drilling. The ground water is perched above the relatively impermeable, unweathered shale within fractures in the overlying severely weathered shale. The depth ta, and amount of ground water, will fluctuate with variations in seasonal and yearly rainfall. Texas Health and Safety Code and TCEQ Comment Pursuant to the Texas Health and Safety Code, Chapter 361, §361.538 and 30 Texas Administrative Code 330, §330.953, Reed Engineering Group, Ltd. has performed appropriate soil tests as required by these regulations to demonstrate that the subject property does not overlie a closed municipal solid waste landfill. The site observations and subsurface data da Page 9 Project No.15431 - 5 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf not indicate the presence of buried municipal solid waste at this site. Based on these data, development of this site should not require a Development Permit, as described in §361.532 and §§33x.951-33x.9b3, Subchapter T. Seismic Site Classi~catian The site has been classified with respect to seismic design criteria contained in the 2x43 International Building Code (IBC}, Section 1 b 15.1.5. The criteria require characterization of the upper lxx feet of subsurface materials. Based on the 1BC criteria, the site is classified as Site Class C in accordance with Table 1 b 15.1.1. ANALYSIS AND RECOMMENDATIONS Potential Vertical Movements Potential Vertical Movements (PVM} were evaluated using an empirical procedure developed by McDowell2 and modified by the Texas Department of Transportation, TxDOT Test Method 124-E~ in conjunction with the soil suction and absorption pressure-swell tests. Based on the PVM calculations and past experience, potential movements are estimated to be on the order of four to five inches. Movement will be associated with seasonal changes in soil moisture. Ground-supported improvements (i.e., sidewalks and paving} will move in response to changes in soil moisture. The movement will be observed as heave if the soils are dry at the time the pavement or sidewalk is constructed. The movement will be observed as settlement if the soils a McDowell, C. "The Relation of Laboratory Testing to Design for Pavements and Structures on Expansive Sails." Quarterly of the Colorado School of Mines, Volume 54, No, 4, 127-153. Page 10 Project No. 15431 - b - May 12, 24x8 (8/3112009) DiWanna Baskins - rp1543101.pdf are moist at the time of construction. Generally, settlement will be limited to the outer perimeter (outer four to five feet) of larger slabs. Prudent watering during extended dry climatic periods can control settlement. Recommendations are provided to limit movement below the building; however, same movement of site paving and sidewalks should be anticipated. The estimated PVM is based on existing site grades. if significant cut and fill will be required below the building to establish finished grade, this office should be consulted for additional analysis and recommendations. Foundation Type, Depth and Allowable Loading Foundation support for concentrated column loads should be provided by auger-excavated, reinforced concrete piers. The piers maybe founded within either the severely weathered shale or the underlying dark gray, unweathered shale. Minimum pier depths and recommended bearing values are provided in Table 2. 3 "Method far Determining the Potential Vertical Rise, PVR." (1978). Texas Department of Transportation, Test Method Tex-124-E. Page 11 Project No. 15431 - 7 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf TABLE 2. RECOMMENDED BEARING Minimum Allowable Skin~3~ Pier Typel Penetration End Bearing Friction Bearing Strata feet) (ksf} (ksf) Underreametl "Belled" Piersl 20.0~'~ 6.5~z~ n.a. Severely Weathered Shale Straight-Shaft Piersl 2.0 18.0 4.5 Dark Gray, Unweathered Shale 1. Minimum penetration for underreamed piers is measured from a Finished Floor of 545.0. Underreametl piers can be belled directly on top of ground water, if encountered. 2. Six and one-half X6.5) kips per square foot ksf) dead load or eight X8.0) ksf total load, whichever governs. 3. Recommended skin friction is applicable for the portion of the pier below the minimum penetration. Based on the borings, the top of dark gray, unweathered shale is anticipated to be located at depths of 21-112 to 23-112 feet {Elev. 519.5 to 518.5} below April 2008 grades. Bid depths should be adjusted based on final site grading. Piers proportioned in accordance with these allowable bearing and skin friction values will have a minimum factor of safety of three considering a shear or plunging failure. The weight of the pier concrete below final grade may be neglected in determining foundation loads. Properly constructed straight-shaft piers should undergo negligible post-construction settlement. Elastic settlement of properly constructed underreamed piers should be limited to approximately''/z inch. Page 12 Project Na. 15431 - 8 - May 12, 20x8 (8/3112009) DiWanna Baskins - rp1543101.pdf A minimum pier-to-pier spacing of two shaft diameters, center-to-center, is recommended for straight-shaft piers. A minimum of two bell diameters, center-to-center is recommended for underreamed piers. If a pier spacing of less than these values is required, this office should be contacted for additional analysis. Piers will be subjected to uplift associated with swelling within the upper clays. The piers should contain reinforcing steel throughout the pier to resist the tensile uplift forces. Reinforcing requirements may be estimated based on an uplift pressure of 1.3 ksf acting over the top 8 feet of pier surface area. The calculated uplift value is considered a working load. Appropriate factors of safety should be applied in calculating the percent of reinforcement. "Mushrooming", or widening of the upper portion of the pier shaft, will significantly increase the uplift pressure from the upper clays. "Mushrooms" should be removed from the piers prior to backfill operations. Pier caps should not be used with the piers unless a minimum void of b inches (Factor of Safety of 1.2) is created below the portion of the cap extending beyond the shaft diameter. Uplift resistance for underreamed piers will be provided by the weight of the soil overlying the bell and the dead load from the structure. A minimum bell-to-shaft diameter ratio of two to one (2:1) is recommended to resist uplift associated with swelling of the upper soils. A maximum bell-to-shaft diameter ratio of 3:1 is recommended to limit possible caving of the bells. Page 13 Project No. 15431 - 9 - May 12, 2008 8/3112009) DiWanna Baskins - rp1543101.pdf Page 1 (8/3112009) DiWanna Baskins - rp1543101.pdf The void can be created below grade beams by use of wax-impregnated cardboard forms or beneath tilt panels by over-excavating the required void space prior to panel erection. Retainer boards along the outside of the grade beam or tilt-wall panel will not be necessary. Grade beams should be double-formed. Earth-forming of beams below ground is not recommended because of the inability to control the beam excavation width. Fill an the outside of perimeter grade beams and/or tilt walls should be placed in a controlled manner. Backfill should consist of site-excavated clays, or equal, placed and compacted in accordance with the Earthwork section. If bedding soils must be used adjacent to the perimeter of the building, the claylbedding soil interface should be sloped to drain away from the building. Compaction criteria are included in the Earthwork section. Floor Slab A number of factors affect the performance of the floor slab, to include traffic and wheel loads, quality of the concrete, joint treatment and condition of the subgrade. The two factors, which affect the condition of the subgrade, are related to post-construction movement and strength of the subgrade. The following sections address the potential for movement and alternatives to reduce the potential and/or probability of the movement occurring. The strength of the subgrade is addressed in the Modulus of subgrade Reaction subsection. Page 15 Project No. 15431 -11 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Potential movements associated with heave from a dry condition to a moist condition are estimated to be an the order of four to five inches. Additional movement is possible if the clays become saturated, such as can happen from utility leaks and excessive ponding adjacent to the perimeter walls. Two types of floor systems are considered feasible; a suspended floor and aground-supported (or "floating"} slab. The suspended floor is considered the most expensive but does provide the highest degree of conf dente that post-construction movement of the floor will not occur. if this alternative is desired, a minimum void of 10 inches (approximate F.S. of 2} is recommended. Use of aground-supported floor is feasible, provided the risk of some post-construction floor movement is acceptable. The otp ential movement can be reduced by proper implementation (i.e., construction} of remedial earthwork recommended in the following paragraphs. The risk of the potential movement occurring can be reduced by implementation of positive grading of surface water away from the building and backfilling immediately adjacent to the structure with on-site clays. Several options and alternatives are provided in the following sections. The purpose of the alternatives is to provide optimum performance of aground-supported slab while limiting unnecessary costs. This office can assist with optimization of the alternatives upon review of proposed finished grades. Page 16 Project No.15~31 -12 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf The most economical way of limiting the potential for post-construction floor movement, and the most positive from a design perspective, is to reduce the potential for heave-related movement prior to construction of the floor. This can be accomplished by either: • mechanically excavating the upper clays, mixing the clays with water, then recampacting the clays at an elevated moisture in controlled lifts; or • preswelling via multiple passes of water pressure injection. of these two, the least expensive, most positive and easiest if erfp ormed rp aperly, is to preswell via the injection process. Both options are presented in the following sections. For the injection alternative, a compacted soil "cut-off wall" will need to be constructed adjacent to the existing building. The cut-off wall should begin at the bottom of the existing grade beam or tilt-wall panel and then be sloped at one horizontal to one vertical (1 H:1 V) to a depth of 12 feet. The excavated soils should then be recampacted in lifts to required grade. The injection process should then be performed outside the area of the "cut-off' wall. At completion of either the injection process or excavation and recompaction process, a surface seal will be required to maintain the desired moisture. Three types of surface seals can be provided: • a minimum of 12 inches of "select" fill; • a minimum of 6 inches of "flexible base"; or • lime stabilization of the top 6 inches of soil with a minimum of 6 percent hydrated lime at completion of reworking ar injection. Page 17 Proj ect No. 15431 -13 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Experience has shown comparable performance for each of the recommended surface treatments. The specific recommendations and general procedures for each of the alternatives are presented in the following subsections. Recommendations relevant to both alternatives are presented in the Other Considerations subsection following the alternative discussions. Finished floor has been set for the building addition at Elev. 545.0. If this finished floor elevation is modified, this office should be consulted. The specific construction schedule is unknown. Currently, the subgrade is relatively moist, and the potential for additional movement is approximately one inch. It is recommended that three 12-foot borings be performed prior to construction to evaluate the in-situ moisture and need far subgrade modification. Pressure Injection 4ptian -This option consists of performing cut and fill balance followed by injection, then providing a surface seal. The performance of an injected subgrade is dependent upon the quality of the workmanship. Therefore, water pressure injection is not recommended unless a representative of this office is present full-time to observe all injection operations. Page 18 Project No. 15431 -14 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Procedures consist of the following. 1, Strip vegetation and dispose of the organic materials in accordance with the project specifications. 2. Cut and fill balance with an-site soils to desired subgrade, dependent upon the specific type of surface seal, Place and compact soils in accordance with recommendations in the Earthwork section. • Note: if insufficient on-site fill exists to achieve the proposed subgrade for the '"select" fill option, all imported fill for use below the building should consist of "select" soils. Balance on-site soils to provide a uniform thickness of "select.'" 3, Perform three 12-foot borings within the building area to evaluate the in-situ moisture, if dry conditions prevail, proceed to Item 4. If moist conditions prevail, proceed to Item 6. 4. Excavate and recompact the "cut-off wall" adjacent to the existing building as described above, 5. Preswell the upper clays via pressure injection with water, Perform injections to Elev. 533.0. Guideline specifications for performance of the injection process are included in the report Specifications. Two guideline Specifications are included; one for the "select" fill and one for the lime stabilization option. (The "select" fill specification should be modified if the flexible base option is used as a cap.} 6. Place and compact the surface moisture barrier, consisting of either: • 12 inches of "select" fill; • 6 inches of TxDOT "Flexible Base", Grade 2, Type D or better; or • stabilize the top 6 inches of injected soil with a minimum of 6 percent hydrated lime. Page 19 Proj ect No. 15431 -15 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf The actual number of injection passes required will be dependent upon the soil moisture conditions at the time of construction. For estimating purposes, and considering dry conditions at the time of construction, three injection passes should be anticipated. Placement recommendations for "select" fill and "Flexible Base" is included in the Earthwork section. Lime stabilization should be conducted in accordance with TxD~T "Standard Specif cations for Construction of Highways, Streets and Bridges," 2004 Edition, Item 260. Lime-stabilized soils should be compacted to a minimum of 95 percent of Standard Proctor density, ASTM D 698. The footprint of the injected area should be extended a minimum of five feet beyond the general building lines. The injection footprint should be increased to 10 feet beyond the building at entrances to limit the potential for differential movement between the structure and sidewalks or entrance pavement. Excavation and Recompaction Option - An alternative method of pre-wetting the upper sails to reduce the potential for post-construction swell consists of excavation of the upper clays, mechanically mixing the clays with water, then recompaction of the excavated clays in controlled lifts, This method of re-wettin the soils is not effective unless the water is uniforml blended with the soil. Simply wetting the surface of the soil will not achieve the required result. Page 20 Project No. 15431 -16 - May 12, 2008 8/3112009) DiWanna Baskins - rp1543101.pdf Page 2 (8/3112009) DiWanna Baskins - rp1543101.pdf The footprint of the reworked area should be extended a minimum of five feet beyond the general building lines. The reworked footprint should be increased to 10 feet beyond the building at entrances to limit the potential for differential movement between the structure and sidewalks or entrance pavement, dther Considerations -The "select" fill, flexible base, or lime caps should be placed within approximately seven working days following completion of either the injection process ar the excavation and recompaction operations to limit moisture lass. Careful consideration should be given to the actual area treated with either of the two alternatives to reduce movement. The potential for post-construction heave will be reduced in the treated areas; however, areas left untreated will result in differential movement. In general, it is recommended the treated area extend beyond the building at entrances to reduce the potential for differential movement among the building, the sidewalk and entrance pavement or in areas where site paving is relatively flat because of drainage or ADA considerations. Potential floor movements associated with heave, considering a properly preswelled or reworked subgrade, are anticipated to be on the order of/z to 1 inch. Positive drainage of water away from the structure must be provided and maintained after construction. Architectural detailing of interior finishes should allow for approximately '/z to 1 inch of differential floor movement, Page 22 Project No.15431 -18 - May 12, 20x8 (8/3112009) DiWanna Baskins - rp1543101.pdf A minimum six-mil thick polyethylene sheet is recommended below the floor to limit migration of moisture through the slab from the underlying soils, This is of particular importance below sections of the floor covered with carpeting, paint or tile. Penetrations and lapped joints should be sealed with a waterproof tape. Ground-supported floors over expansive soils may be subject to settlement if the underlying clays dry during the Life of the structure. Natural desiccation will be limited to the outer four to five feet along the perimeter where surface pavement does not abut the structure. However, roots from trees and shrubs can grow below the structure and increase the zone of desiccation. This process typically requires 8 to 10 years to develop. An effective means of limiting plant root growth is construction of a vertical moisture barrier adjacent to the foundation or extension of paving to the perimeter of the building. if utilized, the barrier should consist of a minimum six-inch wide, five-foot deep lean concrete wall. Trees and shrubs should be planted outside the barrier. Modulus of Subgrade Reaction -- The preceding sections discussed alternatives to reduce the potential andlor probability of post-construction floor movement. Three alternatives were provided to seal the moisture into the Subgrade to reduce construction-related moisture loss. The alternatives included lime stabilization of approximately 6 inches of clay, placement of 6 inches of flexible base, and placement of 12 inches of "select" fill. Considering any of these three options, it is recommended the floor slab be designed using a modulus of Subgrade reaction, k, of 150 pounds per cubic inch (pci). This value is applicable considering placement of a minimum of 12 inches of "select" fill, b inches of flexible base, or Page 23 Project No. 15431 -19 - May I2, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf lime stabilization of 6 inches of subgrade with a minimum of G percent hydrated lime aver the prepared subgrade. To achieve the recommended modulus, compaction of the "select" fill, flexible base, and lime-stabilized clay to the specified density will be required. Materials disturbed by the construction equipment immediately prior to placement of the concrete will reduce the allowable modulus. Various alternatives are available to increase the effective modulus of subgrade reaction. One alternative consists of stabilization of the top six inches of "select" fill with a minimum of six percent cement. Another alternative consists of placement and compaction of a minimum of 6 inches of flexible base on top of compacted "select" fill ar lime-stabilized clay, or increasing the flexible base thickness to 12 inches. Either of the two alternatives would increase the k value to approximately 225 pci. Other combinations to increase the allowable modulus are feasible and will be addressed if desired. Retaining Walls Lateral earth pressures against retaining walls will be a function of the backfill within the "active zone" of earth pressure. The "active zone" can be estimated as an included angle of 35° from the vertical, extended upward from the base of the wall. Considering backfill using site-excavated materials, lateral earth pressures can be estimated based on an equivalent fluid pressure of 60 pounds per cubic foot (pcf) for active conditions, or 80 pcf for at-rest conditions. Alternatively, imported "select" fill may be used as backfill in the active zone. Considering "select" fill, lateral earth pressures can be estimated based on an equivalent fluid pressure of 35 pcf, active conditions, or 50 pcf at-rest conditions. Page 24 Project No. ] 5431 - 20 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Rotation, or lateral movement on the tap of the wall, equal to 0.02 times the height of the wall will be necessary for on-site soil backfill for the "active" condition. Lateral movement of the top of the wall equal to 0.041 times the height of the wall will be necessary for the "active'" pressure condition for "select" fill backfill. The lateral earth pressures are applicable for horizontal surface grades and non-surcharged, drained conditions. A drainage system should be installed behind the base of the retaining walls to limit development of excess hydrostatic pressures. The drainage system should consist, as a minimum, of 12-inch by 12-inch packet drains spaced 15 feet on-center, installed near the base of the wall. Fill in the pocket drains should consist of durable crushed stone such as ASTM C 33, Sipe b7 ar coarser, wrapped in filter fabric (ADS 600 or equivalent}. Backfill around the gravel drain should consist of site-excavated soils or "select" fill. A compacted clay cap is recommended within the upper two feet of the surface to limit surface-water infiltration behind the walls. Retaining walls may be founded on spread or continuous footings placed a minimum of 18 inches into undisturbed, on-site soils or compacted and tested fill. Footings should be proportioned far a maximum bearing pressure of 3,000 pounds per square foot (psfJ. Movement of the footings and walls should be anticipated. If the potential for differential movement is not acceptable, the walls should be supported on piers and designed using the Foundation section. Page 25 Project No. 15431 w 21- May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Passive resistance to lateral movement can be estimated based on an equivalent fluid pressure of 550 pcf for on-site materials. This value is applicable for footings founded on undisturbed, on-site sails or compacted and tested fill. In addition to passive resistance, a coefficient of friction between the base of the footing and the underlying soil equal to 0.38 maybe used. The lateral earth pressure values do not incorporate specific factors of safety. If applicable, factors of safety should be integrated into the structural design of the wall, Any earth slope greater than eight feet in height should be evaluated for global stability, This also applies to slopes combined with retaining walls that have a combined height in excess of eight feet. Global stability analysis was not within the scope of the present investigation. This office can assist in the analysis if desired. All constructed slopes should be vegetated as soon as possible. Use of erosion control fabric is recommended during vegetation of the slopes. The recommendations above are applicable for retaining walls that are not subject to inundation by water. Modification of the recommendations maybe necessary for wet applications (such as detention ponds, water features and along creek beds}. This office should be provided with grading plans and wall layouts to review for any necessary modifications to the recommendations for wet applications. Earthwork All vegetation and topsoil containing organic material should be cleared and grubbed at the beginning of earthwork construction. Areas of the site that will underlie fill or within the building should be scarified to a depth of 6 inches and recompacted to a minimum of 92 percent Page 26 Project No. 15431 - 22 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf and a maximum of 98 percent of the maximum density, as determined by ASTM D b9$, "Standard Proctor". The moisture content should range from +l to +6 percentage points above optimum. Site-excavated sails should be placed in maximum eight-inch loose lifts and compacted to the moisture and density requirements outlined above. The soils should be uniformly blended with water to achieve the required moisture content. The final b inches of subgrade below pavement should be compacted to a minimum of 9S percent of Standard Proctor, at or above optimum moisture. Areas where compaction utilizing hand-held equipment will be required, such as for site utilities and perimeter "leave-out strips" (tilt-wall construction), should be compacted to a density of between 9S and 98 percent of Standard Proctor, at a moisture content of between +l to +5 percentage paints above optimum. Proper backfilling around the building perimeter will reduce the potential far water seepage beneath the structure. Fill against the perimeter of the foundation should consist of site- excavated clays, or equal, placed and compacted in accordance with the recommendations outlined above. Page 27 Project No. 15431 - 23 - May 12, 2008 8/3112009) DiWanna Baskins - rp1543101.pdf Page 28 (8/3112009) DiWanna Baskins - rp1543101.pdf Information regarding the specific traffic loads and frequency is not available. Therefore, analysis was performed for a range of traffic conditions, and design thickness versus traff c load diagrams were developed. The pavement type has been identified as concrete. Analysis was performed for both 3,000 pounds per square inch (psi) and 4,000-psi compressive strength concrete. Based on correlations between compressive strength and flexural strength and incorporating a factor of safety of 1.33, an allowable working stress of 370 and 425 psi was used for the 3,000- and 4,000-psi concrete, respectively. Control of the water-cement ratio at the design value during placement and use of quality construction will be necessary to achieve the required flexural strength. A 20-year life was used far the analysis. Total pavement life was based an a six~day week. Analysis was performed in accordance with procedures developed by the American Association of State Highway and Transportation Officials (AASHTO). The upper surface soils consist of high plasticity clays. When these soils are moist, they are relatively soft. Far purposes of pavement analysis, the subgrade was assumed to be recompacted in accordance with the density and moisture recommendations in the Earthwork section and in a moist condition. An effective modulus of subgrade reaction, k, of 100 pci was used for the analysis. Page 29 Project No. 15431 - 25 - May 12, 2x08 (8/3112009) DiWanna Baskins - rp1543101.pdf The effective k value of the subgrade can be increased to 150 pci by stabilization of the upper 6 inches with a minimum of 6 percent hydrated lime. Lime should be placed and compacted in accordance with ltem 260 of the current edition of TxDOT "Standard Specifications for Construction of Highways, Street and Bridges." The lime-stabilized subgrade should be compacted to a minimum of 100 percent of ASTM D 698 density {Standard Proctor). Generally, it is mare cost-effective to increase the pavement thickness and construct over a nan- lime stabilized subgrade. However, stabilization does provide an all-weather working platform far the contractor, and this may be beneficial from a construction perspective, especially if construction will occur during the wetter part of the year. Stabilization is also recommended if the traffic speed exceeds 30 miles per hour (mph), Considering the above discussion, analysis was made for both unlimited repetitions of cars and light trucks and far multiple repetitions of loaded tractor trailers. Analysis indicates a pavement thickness of 4.5 inches of 3,000-psi concrete will be adequate far car and light truck traffic. A minimum five-inch section over a scarified and recompacted subgrade is recommended. Pavements subject to multiple repetitions of tractor-trailer traffic were analyzed using both 3,000- and 4,000-psi concrete. Trailers were assumed to be loaded to the maximum allowable weight, SO kips, consisting of two sets of tandem axles loaded to 32 kips and one 16-kip axle. Recommended sections for various rates of truck traffic, based an number of repetitions per day for asix-day week, are provided in the following tables. Page 30 Project No. 15431 - 26 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf TABLE 3. (K-=100 PCI~ NUMBER OF TRUCK REPETITIONS VS. PAVEMENT THICKNESS 3,000~PS1 COMPRESSIVE STRENGTH Pavement Thickness inches No. of Repetitions er da 6 minimum recommended for fire Panes) 9 7 22 8 52 9 110 TABLE 4. (K=100 PCI} NUMBER OF TRUCK REPETITIONS VS. PAVEMENT THICKNESS 4,000-PSI COMPRESSIVE STRENGTH Pavement Thickness inches No. of Repetitions er da 6 13 7 33 8 82 9 163 Analysis of Tables 3 and 4 indicates an approximate 50 to 80 percent increase in the number of truck repetitions can be obtained by increasing the concrete strength from 3,000 psi to 4,000 psi. An increase of 100 to 150 percent is realized by increasing the thickness of the pavement by 1 inch. Page 31 Proj ect No. 15431 - 27 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Although not provided herein, analysis of the allowable repetitions was also performed considering a stabilized subgrade. For any given pavement thickness and strength of concrete, an increase in the number of repetitions equal to 20 to 33 percent of the non-stabilized repetitions is realized. Considering the relative costs associated with stabilizing the subgrade, a greater increase in repetitions (i.e., pavement life) is realized by increasing the pavement thickness or strength versus stabilization of the subgrade. Pavements should be lightly reinforced if shrinkage crack control is desired. Reinforcing for 5- and b-inch pavements should consist of the equivalent of #3 bars (metric # 10) at 24 inches on- center, and 18inches on-center for pavements of 7-inch thickness or greater. Pavement sections should be saw cut at an approximate spacing in feet of 2.5 to 3 times the pavement thickness expressed in inches, not to exceed a maximum spacing of 20 feet. (For example, a 5-inch pavement should be saw cut in approximate 12.5- to 15-foot squares.) The actual joint pattern should be carefully designed to avoid irregular shapes. Recommended jointing techniques are discussed in detail in "Guide for Design and Construction of Concrete Parking Lots," published by the American Concrete Institute4. The above sections are based on the stated analysis and traffic conditions. Additional thickness or subgrade stabilization maybe required to meet the City of Coppell development code. a "Guide for Design and Construction of Concrete Parking Lots" (1487). American Concrete Institute, Publication MSP 34, Silver Spring, MD. Page 32 Project No. 15431 - 28 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf Pavement Joints Detailing of the pavement is beyond the proposed scope of geotechnical services. However, the following discussion is offered to assist the pavement designer and reduce the ambiguity associated with joint detailing. There are four common types of pavement joints: contraction or saw joints, isolation joints, construction joints, and expansion joints. Each of these are defined and discussed in the following paragraphs. Contraction Joints -Contraction or saw joints are installed in concrete to reduce the potential for random shrinkage cracks associated with drying of the plastic concrete. Concrete shrinks (contracts} at an approximate rate varying from 0.0002 inch/inch to .0008 inchlinch, dependent upon the specific water to cement ratio. The higher shrinkage is for a higher water to cement ratio. Using an average coefficient of 0.00047 inch/inch results in 0.5~ inches of shrinkage per 100 feet of pavement. The general "rule of thumb" is to space contraction joints three times the concrete thickness, where the thickness is expressed in inches and the spacing is expressed in feet, up to a maximum spacing of 20 feet. Far example, a 6-inch thick pavement should have contraction joints spaced at approximately 18feet an-center. Page 33 Project No. 15431 - 29 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf The joint is commonly constructed by sawing a groove to a depth of approximately 113 the thickness of the slab. The purpose of this groove is to create a weakened plane, thus inducing a shrinkage crack to form. The weakened plane must be constructed while the concrete remains relatively plastic, generally within the first four to six hours of placement, or else shrinkage cracks will have already farmed. A limited amount of mild steel is generally used to reduce formation of random contraction joints. The typical amount of steel is #3 reinforcing bars {metric #10) at approximately 24 inches on-center far 5-and 6-inch pavement. The spacing is typically reduced to 1$ inches on- center for pavements of 7-inch thickness or greater. Local practice is to extend the reinforcing uninterrupted through the saw joint. This practice can restrict formation of the joint, leading to an increase in the potential for shrinkage cracks occurring outside the formed joint. This practice is however, beneficial from an expansive soil perspective in that it reduces the potential for opening of un-reinforced joints associated with heave of the subgrade. Isolation Joints -Isolation joints are placed in concrete to separate various elements. Far example, an isolation joint is generally used where concrete pavement abuts the building foundation. There is generally no structural connection between the two constructed elements. Construction Joints -Construction joints are required by the contractor to delineate various placement operations. An example of a typical construction joint is the bulkhead at the end of a pour, ar the bulkhead used to delineate individual pour strips. Page 34 Project No. 15431 - 30 - May 12, 200$ (8/3112009) DiWanna Baskins - rp1543101.pdf Transfer of stress through a typical contraction (saw) joint is a result of interlocking of the concrete aggregate in the non-sawed portion of the joint and the steel traversing the joint. Because the construction joint is formed, there is no interlocking of the concrete aggregate. Far this reason, it is recommended that as a minimum, the quantity of contraction steel be doubled through a construction joint. For example, if the contraction steel is equal to #3 bars at 1$ inches on-center, it is recommended that additional #3 bars be added, spaced 9 inches from the contraction steel, The added bars should be a minimum of three feet in length centered at the formed joint. Alternatively, smooth dowels can be used to increase the amount of reinforcing through the construction joint. The amount of dowel steel varies and should be detailed by the pavement designer. Expansion Joints -Expansion joints are used in concrete to allow for thermal expansion and/or contraction. The thermal coeff dent of concrete varies dependent upon the coarse aggregate from approximately 6.6 x 10-61°F for quartz to 3.8 x 10-GI°F for limestone. The majority of coarse aggregate used in concrete within the North Texas region consists of limestone, therefore the lower value of the thermal coeff dent is considered to be applicable. Use of 3.8 x 10-b/°F results in an estimated 0.4b inches of expansion ar contraction per 100 feet of concrete per 100°F change in the concrete temperature. Based an the calculation presented for the average plastic shrinkage, the potential far thermal expansion (0.4b inches per 100 feet of concrete per 100°F) is less than the average anticipated plastic shrinkage (0.56 inches per 100 feet of concrete). Page 35 Proj ect No. 15431 - 31- May 12, 200$ (8/3112009) DiWanna Baskins - rp1543101.pdf In conclusion, the above analysis indicates that for the average construction project and where limestone is used for the coarse aggregate, expansion joints are not required. Construction Observation and Testing Frequency It is recommended the following items {as a minimum) be observed and tested by a representative of this office during construction. • Fill placement and compaction. • Pressure-injection operations. • Pier construction and concrete placement. Te~ stingy • Earthwork • One test per 5,000 square feet per lift within fills below the building. • One test per 10,000 square feet per lift within Ells in the paving area. • One test per 150 linear feet per lift in utility and grade beam backfill. • One test per 100 linear feet per lift in retaining wall backfill. • Post-injection borings, one boring per 10,000 square feet of injected area. The purpose of the recommended observation and testing is to confirm the proper foundation bearing stratum and the earthwork and building pad construction procedures. Page 36 Project No.15431 - 32 - May 12, 2008 (8/3112009) DiWanna Baskins - rp1543101.pdf ;~ S i } ~. I lY ^ ~ ~ r ~ - _ 4~ ~ I 1 ' I i ... 1 J S~ 1 il~ ` __ I I Page 37 8/3112009) DiWanna Baskins - rp1543101.pdf rccrl anninoarinn .. ~ .. GROUP Cici's Pizza Distribution Addition Project No. 15431 Bethel Road Coppell, Texas Date: 04-25-0$ Location: See Plate 1 ~-' J ~ CORE Pocket Penetrometer Readings Tans Per Sq. Ft. -'~ Z o ~ a ~ Standard Penetration Tests ^ ~ ~-' ~ w v m ~ ~ ~ ~ ~ DESCRIPTION OF STRATA i3iows per Foot - ~ > a~~i N w ~ w " ^ cn N w ~ ~ ~ ~ 1 2 3 A 4.5+ 4.5++ W ° ~ ~ ~ 10 20 3Q 40 50 6(l Q 542 CLAY, dark brown, very stiff (CH) 5 533 5 SILTY CLAY, yellowish-brown ~ pale at r v l 0 4- & 0 . 1o brown, stiff (severely weathered silty shale) (CH) 529 SILTY CLAY, olive-~yellaw, hard, wliron ~ ee a e ur ng dr ' 15 stains, blocky (severely weathered silty shale) (CH) 52a 5 CLAY, olive-brown, hard, w/silt . (severely weathered shale) (CH) 20 wlsome shale seams below 21' 520 __ __= SHALE, dark gray, soft, wlsome iron --- stain laminations, slightly fissile 518.5 25 =_= SHALE, dark gray, soft --- - 1 0 t 1 1 i s 515 o s s Total Depth = 27 feet 30 Seepage encountered @ 14' during drilling. Water @ 21-112' after 5 minutes. Water @ 19-1/2' ~ blocked @ 26' @ end of day. Water @ 9' 6 blocked @ 24' on 04-28-0$. 35 40 BDRING LOG B-1 PLATE 2 r,~nT~nrurrei rrw~ a Teu~~ Page 38 8/3112009) DiWanna Baskins - rp1543101.pdf rnod nnninnnrinn .. ~R~uP Cici's Pizza Distribution Addition Project No. 15431 Bethel Road Coppell, Texas Date: 04-25-08 Location: See Plate 1 ~' ~ cn CORE Pocket Penetro~eter Readings Tons Per Sq. Ft. ~~ Z o _ ~' ~" o w Standard Penetration Tests ~ w ~ U ~ ~ v ~ DESCRIPTION OF STRATA Blows per Foot - + ~ v ~ w w " o cn ~ w © °~ ° ~ 1 2 3 4 4.5+ A.5tt w oe ~ 410 20 30 40 50 60 0 54$ CLAY, brown ~ reddish-brown, hard, 546 5 wlsome fine gravel (CH) . SILTY CLAY, grayish-brawn, hard, 545 w/some calcareous nodules (CL) 5 SILTY CLAY, olive-yellow, hard, wliron 542 stains ~ some calcareous deposit seams, blocky (severely weathered silty shale) (CIS - ~o CL) Total Depth = B feet Dry @ completion. 15 20 25 30 35 40 BORING LOG B-3 PLATE 4 r.~nTGruumei rtwa i~ TaNTc Page 40 8/3112009) DiWanna Baskins - rp1543101.pdf rcori annincarinn aRaul~ Cici's Pizza Distribution Addition Project No. 15431 Bethel Road Coppell, Texas Date: 04-25-OS Location: See Plate 1 _ {-' w ~ N "' o w CORD Packet Penetrometer Readings Tons Per Sq. Ft. -~ Standard Penetration Tests Z O ~' w ~ ~ ~ ~ ~ o DESCRIPTION OF STRATA Blaws per Foot - ~ ~ a~~i w w" ^ ~N w ~ ~ ~ ~ ~ 1 2 3 4 4.5t A.5tt W ~ ~ t 10 20 30 40 50 6(l Q 535 CLAY, dark brown, very stiff (CH) 533 CLAY, brown, hard, w/silt (CW) 532 CLAY, olive-yellow, hard, w/iron stains, ~ some calcareous deposit seams, blocky 529 (severely weathered silty shale) (CH - CL) ~o Tota! Depth = 6 feet Dry @ completion. 15 20 25 34 35 40 BORING LOG B-4 PLATE 5 r,GnrGn.uTr~~ rn~a n re~~~ Page 4 (8/3112009) DiWanna Baskins - rp1543101.pdf 9~9 GROUP rood ^nninoorinn Fill Type of Fill Cici's Pizza Distribution Addition GROUP Project No. 15431 Bethel Road pafe: 04-25-08 COppe, T2XaS Location: See Plate 1 ~ ~ CORE Pocket Penetrometer Readings z _ ~--. ~ ~ ~ 7on5 Per Sq. fit. -~ ~ ; ~ ~ ~ ~ ~ m ~ ~ ~ ~- ~ U ~ DESCRIPTION OF STRATA Standard Penetration Tests Blows per Foot - 0 ~- ~, Q ~ ~~ ^ cn~ o ~ ~ ~ + 4. 5 w 3 p b 10 0 30 40 50 CLAY, dark brown, very stiff (CH) 5 533 5 - SILTY CLAY, yellowish-brown ~ a er l ve o q 2 - g . 10 pale brown, stiff (severely weathered silty shale) (CH) ~ 529.0 - SILTY CLAY, olive-yellow, hard, e p g ur n d i g 15 w/iron stains, blocky (severely weathered Silty shale) (~ ~ I 524.5 CLAY, olive-brown, hard, w/silt ~0 (severely weathered shale) (CHI WI50~e Shale Seal115 b210W 21' 520.0 _= SHALE, dark gray, soft, w/some 5ie.5 25 __= Ir011 5talll Iaf~Inat10C15, Slightly f15511e == SHALE, dark gray, soft ~-- i B io s =- 1- 11 i c 550 Total Depth = 27 feet 30 - Seepage encountered @ 14' during drllling, Water @ 21-112' after 5 minutes. Water @ 19--112' S blocked @ ?6' @ end of day, Water @ 9' ~ blocked @ 24' on 35 pG9--28-08. 0 BORING LOG B-1 PLATE 2 __.. r_~nr~runirrni rn~ici o 7nR~~~ UNDISTURBED (Shelby Tube ~ NX-Core) DISTURBED STANDARD PENETRATION TEST THD CONE PENETROMETER TEST CLAY (CL) (LL<50) CLAY (CH) (LL>50) SILT (ML) (LL<50) SILT (MH) (LL>50) ~, ; CLAYEY SAND (SC) :~ ~: SILTY SAND (SM) .. SAND (SP-SW) CLAYEY GRAVEL (GC) 0~ GRAVEL Op (GP-GW) r (weathered) _ ~ SFEALE -== (unweathered) (weathered) LIMESTONE (unweathered) .~.> (weathered) SANDSTONE '•' (unweathered) V =Water level at time of drilling. Z =Subsequent water level and dale, Page 42 KEYS TO SYMBOLS USED ON BORING LOGS PLATE 6 C~QTEq-NICAL ~SULTANTS 8/3112009) DiWanna Baskins - rp1543101.pdf Page 43 (8/3112009) DiWanna Baskins - rp1543101.pdf Summary of Classificatio ~ Moisture Boring Depth Content No. feet ~%~ B-1 1.5 - 3.0 23.4 n and Index Property Tests Tota Liquid Plastic Plasticity Soil Limit Limit Index Suction ~~ ~ -- -- -- 4, 610 ~, 3.0 - 4.5 26.8 62 19 43 3,450 ~'~, 4.5 - 6.0 27.8 -- -- -- 7, 790 9.0 - 10.0 34.6 56 25 31 1,250 14.0 - 15.0 31.5 -- -- -- 3,880 19.0 - 20.0 29.1 -- -- -- 2,360 ~~ ~, B-2 1.5 - 3.0 28.2 -- -- -- 1,580 3.0 - 4.5 31.8 -- -- -- 3,150 4.5 - 6.0 32.2 77 26 51 3,800 9.0 - 10.0 30.3 -- -- -- 3,180 I, 14.0 - 15.0 ~ 30.0 65 24 41 8, 960 ! 19.0 - 20.0 ',, 26.6 -- -- -- 3,450 SUMMARY OF LA64RATORY TEST RESULTS PLATE 8 Page 44 (8/3112009) DiWanna Baskins - rp1543101.pdf Uly UIILUIIIIIIGU Moisture Unit Compressive Sample Boring Depth Content Weight Strength Legend No. feet °~/~ c ks A B-1 14.0 -15.0 29.5 92.7 5.9 B B-2 19.0 - 20.0 31.0 88.1 4.5 r ~I ~ I' 5 ~4 ~. ~' 3 .~.. 2 1 0 --w A fB 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 strain (%} Page 45 __ _ _ _ _ __ __ - SUMMARY OF LABORATORY TEST RESULTS PLATE 9 (8/3112009) DiWanna Baskins - rp1543101.pdf ~~~za ~n~in~Er~in~ ~r~ou~ Project No. Boring No. Depth (ft? Liquid Limit Plasticity Index Cs alpha Percent Swell 0.8 0.6 .. 3 N 0.4 m 0.2 Absorption Pressure Swell Test Initial Final 15431 Moisture Content {%) 30.9 32.3 B-2 Penetrometer (tsf) 4.5+ 3.75 14-15 Dry Unit Weight {pcf) 88.5 88.0 65 Specific Gravity 2,71 2.71 41 Vaid Ratio 0.910 0,921 0.027 Saturation (%) 92 95 0.30 Spec. Volume O.10 0.71 0.6 Swell Pressure (psf) 650 250 0 100 u. ~~ i v v a N o.7a Restraining Swell Pressure (psf~ 1000 30.0 32.0 __ __ . _ MQistur~ Content_~%~ __ _.. ABSORPTION PRESSURE SWELL TEST PLATE 10 Page 46 (8/3112009) DiWanna Baskins - rp1543101.pdf GUIDELINE SPECIFICATIONS SOIL MODIFICATION WATER INJECTION W/"SELECT" FILL CAP FOR CICI'S PIZZA DISTRIBUTION ADDITION BETHEL ROAD COPPELL, TEXAS Site Preparation Prior to the start of injection operations, the building pad should be brought to finished subgrade, minus select fill, and staked out to accurately mark the areas to be injected. Allowance should be made for four to five inches of swelling that may occur as a result of the inj ection process. Materials 1. The water shall be potable, with added surfactant, agitated as necessary to ensure uniformity of mixture. 2. A nonionic surfactant (wetting agent} shall be used according to manufacturer's recommendations; but in no case shall proportions be less than one part (undiluted) per 3,500 gallons of water. Equipment 1. The injection vehicle shall be capable of forcing injection pipes into soil with minimum lateral movement to prevent excessive blowback and loss of slurry around the injection pipes. The vehicle may be a rubber tire or trac machine suitable for the purpose intended. ~. Slurry pumps shall be capable of pumping at least 3,000 GPH at 100 - 200 pounds per square inch {psi}. Application 1. The injection work shall be accomplished after the building pad has been brought to finished subgrade, minus select f 11, and prior to installation of any plumbing, utilities, ditches ar foundations. 2. Adjust injection pressures within the range of 100 - 200 psi at the pump. Project No. 15431 -1 - VL~ater Injection Specifications May 12, 2008 w/"Select" Fill Cap Page 47 (8/3112009) DiWanna Baskins - rp1543101.pdf 3, Space injections not to exceed five feet on-center each way and inject a minimum of five feet outside building area. Inject 10 feet beyond building at entrances. 4, Perform injections to Elev. 533.0. Impenetrable material is the maximum depth to which two injection rods can be mechanically pushed into the soil using an injection machine having a minimum gross weight of 5 tons. Injections to be made in 12-inch to 18-inch intervals down to the total depth with a minimum of 8 stops or intervals. The lower portion of the injection pipes shall contain a hole pattern that will uniformly disperse the slurry in a 360° radial pattern, Inject at each interval to "refusal." Refusal is reached when water is flowing freely at the surface, either out of previous injection holes ar from areas where the surface soils have fractured. Fluid coming up around, or in the vicinity, of one or more of the injection probes shall not be considered as soil refusal. If this occurs around any probe, this probe shall be cut off so that water can be properly injected through the remaining probes until refusal occurs far all probes. In any event, no probe shall be cut off within the first 30 seconds of injection at each depth interval. 5. Multiple injections with water and surfactant will be required. The second injection shall be orthogonally offset from the initial injection by 2-112 feet in each direction. Subsequent injections shall be offset such that existing probe hales are not utilized. 6. A minimum of 48 hours shall be allowed between each injection pass. 7. Injections will be continued until a pocket penetrometer reading of 3.0 tsf or less is obtained on undisturbed soil samples throughout the injected depth. The engineer of retard can waive this requirement if, in his opinion, additional injections will not result in additional swelling. 8. At the completion of injection operations, the exposed surface shall be scarified and recampacted to a density between 92 and 98 percent of maximum ASTM D 698 density, at or above optimum moisture. A minimum of 12 inches of select fill shall be placed over the injected subgrade as soon as is practical after completion of injection operations. Select fill should be placed in maximum loose lifts of 8 inches and compacted to at least 95 percent of maximum density, ASTM D 698, at a moisture content between -2 to +3 percentage paints of optimum. Page 48 Project No. 15431 - 2 - Water Injection Specifications May 12, 200$ wl"Select" Fill Cap (8/3112009) DiWanna Baskins - rp1543101.pdf Observation and Testing 1. A full-time representative of Reed Engineering Group, Ltd. will observe injection operations. 2. Undisturbed soil samples will be obtained continuously throughout the injected depth, at a rate of one test hole per 10,000 square feet of injected area for confirmation. Sampling will be performed a minimum of 48 hours after the completion of the final injection pass. Page 49 Project No. 15431 - 3 - Water Injection Specifications May 12, 2008 wl"Select" Fill Cap 8/3112009) DiWanna Baskins - rp1543101.pdf Page 50 (8/3112009) DiWanna Baskins - rp1543101.pdf 4. Perform injections to Elev. 533.0. Impenetrable material is the maximum depth to which two injection rods can be mechanically pushed into the soil using an injection machine having a minimum gross weight of 5 tans. Injections to be made in 12-inch to 18-inch intervals down to the total depth with a minimum of S stops or intervals. The lower portion of the injection pipes shall contain a hale pattern that will uniformly disperse the slurry in a 360° radial pattern. Inject at each interval to "refusal". Refusal is reached when water is flowing freely at the surface, either out of previous injection holes or from areas where the surface soils have fractured. Fluid coming up around or in the vicinity of one or more of the injection probes shall not be considered as soil refusal. If this occurs around any probe, this probe shall be cut off so that water can be properly injected through the remaining probes until refusal occurs for all probes. In any event, no probe shall be cut off within the first 30 seconds of injection after refusal at each depth interval. (The 30-second criterion is not the maximum time for each depth interval but a minimum time. Additional time may be required to achieve refusal, dependent upon the contractor's equipment.} 5. Multiple injections with water and surfactant will be required. The second injection shall be orthogonally offset from the initial injection by 2-112 feet in each direction. Subsequent injections shall be offset such that existing probe hales are not utilized. 6. A minimum of 48 hours shall be allowed between each injection pass. 7. Injections will be continued until a pocket penetrometer reading of 3.0 tsf or less is obtained on undisturbed sail samples throughout the injected depth. The engineer of record can waive this requirement if, in his opinion, additional injections will not result in additional swelling. 8. At the completion of injection operations, the exposed surface shall be scarified and blended with a minimum of 6 percent hydrated lime, or 27 pounds of lime per square yard to a depth of 6 inches. The subgrade shall then be recompacted to a density of between 95 and 100 percent of maximum ASTM D 698 density at or above optimum moisture. Page 51 Project No. 15431 - 2 - Water Injection Specifications May 12, 2008 w/Lime-Modified Cap (8/3112009) DiWanna Baskins - rp1543101.pdf Observation and Testing 1. A full-time representative of Reed Engineering Group, Ltd. will observe injection operations. 2. Undisturbed sail samples will be obtained continuously throughout the injected depth, at a rate of one test hole per 10,000 square feet of injected area for confirmation. Sampling will be performed a minimum of 48 hours after the completion of the final injection pass. Page 52 Project No. 15431 - 3 - Water Injection Specifications May 12, 2008 wlLime-Modified Cap