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CF-Fire Station 1-SY 950501
Geotechnical Exploration PROPOSED FIRE STATION Southwestern Boulevard CoppeR, Texas ATEC Report No. 25-02-95-00091 City of Coppell 500 Southwestern Boulevard Coppell, Texas 75019 Attention: Mr. Clay Phillips May 1, 1995 ATEC Associates, Inc. ~' '~t:,.~¢"~.~;' 11356 Mathis Avenue :~. :.i~* ,?-¢'. ,~ ~,,~ Dallas, Texas 75229-3157 ~!~.~ (214) 556-2204, FAX (214) 556-1753 May 1, 1995 City of Cop~ll 5~ Southwestern ~ulev~d Cop~ll, Texas 75019 Attention: Mr. Clay Phillips Subj~t: G~t~hnicfl Exploration PRO~S~ ~ STATION Sou~weste~ ~ulev~d Cop~H, Texas A~C Re~ No. 25-02-95-~91 D~ Mr. Philips: A~C Ass~iates, Inc. (ATEC) has complet~ ~e geotechni~ explora~on at ~e above referenc~ proj~t site. This study was complet~ in accord~ce with ATEC Pro~s~ No. 25- 02-95-~217 dat~ Feb~ 27, 1995 ~d au~ofiz~ by your Purchase Order Number 012378 dat~ M~ch 9, 1995. ~is re~ con,ns the results of our ~md~gs, ~ engin~fing inte~remfion of these with reset to ~e av~lable project ch~actefisfics ~d r~ommenda~ons to ~d design ~d cons~cfion of founda~ons ~d o~er ~ connec~ phases of this project. We wish to remind you that ~1 soil ~d rock ~mples ob~n~ dung the field ~ves~gation will be re~n~ for a ~fiod of 30 days ~d then disc~d~ unless you r~uest othe~ise. We appr~iate the op~unity to be of se~ice on this project. After you have had oppo~uni~ to review this re~, we will contact you to ~swer ~y ques~ons you may have. ~ ~e m~fime, if we c~ be of fu~er assis~ce, pl~se c~l us at (214) 556-2204. Sincerely, ~-~ Or ATEC ASSOCIATES, INC. C. R~d~ French, E.I.T. Dou~ P. cc: (3) Client (1) Phillips Swager Associates - G. Schon C~/DPZ:crf American Testing and Engineering Corporation Consulting Environmental, Geotechnical and Offices in Major U.S. Cities/Since 1958 Materials Engineers TABLE OF CONTENTS 1.0 INTRODUCTION ........................................ 1 2.0 PROJECT CHARACTERISTICS ............................... 1 3.0 GENERAL SUBSURFACE CONDITIONS ......................... 2 3.1 General Area Geology ................................ 2 3.2 Soil Profile ...................................... 3 3.3 Groundwater Conditions .............................. 4 4.0 DESIGN RECOMMENDATIONS .............................. 5 4.1 General Considerations ............................... 5 4.2 Drilled Shaft and Grade Beam Foundation Systems .............. 8 4.2.1 Underreamed (belled) Shaft Foundations ................ 8 4.2.2 Uplift Considerations and General Design Recommendations .... 8 4.3 Floor Slab on Improved Subgrade Material ................... l0 4.3.1 Cut/Fill Only (Option 1) .......................... 10 4.3.2 Lime Slurry/Water Injection (Option 2) ................. 11 4.3.3 General Recommendations ......................... 13 4.4 Pavement Design ................................... 13 4.5 Drainage ........................................ 16 5.0 GENERAL CONSTRUCTION PROCEDURES AND RECOMMENDATIONS . . . 17 5.1 Site Preparation and Grading ............................ 17 5.2 Drilled Shaft Excavations .............................. 18 5.3 Lime Slurry and Water Pressure Injections ................... 19 5.4 Fill Placement and Compaction .......................... 20 5.5 Groundwater ..................................... 21 6.0 QUALIFICATIONS OF RECOMMENDATIONS ..................... 21 IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL REPORT APPENDIX Figure 1 - Boring Location Plan Field Investigation Procedures Laboratory Investigation Procedures Table 1 - Free Swell Test Results Record of Soil Exploration Sheets (Boring Logs) Key to Soil Symbols and Classification Guideline Specifications for Lime Slurry/Water Pressure Injections Geotechnical Exploration PROPOSED FIRE STATION Southwestern Boulevard Coppell, Texas ATEC Report No. 25-02-95-00091 1.0 INTRODUCTION ATEC Associates, Inc. (ATEC) was retained by the City of Coppell, Texas to perform a geotechnical exploration for the proposed fire station facility to be constructed along Southwestern Boulevard, just west of its intersection with Coppell Road in Coppell, Texas. The site and our understanding of the proposed construction are described in more detail in Section 2.0. The purpose of this geotechnical exploration was to determine the general subsurface conditions at the proposed construction site by drilling test borings and evaluating these with respect to the foundation concept and design. The subsurface conditions found in the five test borings drilled for this project are summarized in Section 3.0. The design recommendations for the foundation, floor slab, and pavement systems are presented in Section 4.0. Also included is an evaluation of the site with respect to potential construction problems and recommendations dealing with the earthwork quality control testing during construction. The recommendations pertaining to construction are included in Section 5.0. Qualifications of our recommendations are discussed in Section 6.0. Text figures, field and laboratory investigation procedures and test results are included in the Appendix along with the boring logs. 2.0 PROJECT CHARACTERISTICS The subject site for the proposed facility is located on the northern side of Southwestern Boulevard, just west of its intersection with Coppell Road in Coppell, Texas. The property is approximately 1.3 acres in size. It is bound on the west by vacant, undeveloped land. An elevated water tank for the City of Coppell is located contiguous to the sites northern border. City of Coppell fire and administration offices are located east of the subject property. The subject property has frontage and is accessed from Southwestern Boulevard on its southern boundary. The property for the proposed fire station was covered with various short to medium height grasses and weeds on the dates of our field activities. The topography of the site is fairly flat with slight undulations scattered about the property. The site did hold ponded water after rainfall events during the completion of our field activities. The elevation change across the site is on the order of 1 to 3 feet. It is our understanding that the proposed structure will consist of a single-story, steel-framed structure with a brick facade. It is anticipated that the new structure will be supported on a deep, drilled shaft, foundation system with the floor slab constructed on an improved subgrade. Anticipated building loads were not provided prior to the submission of this report. 3.0 GENERAL SUBSURFACE CONDITIONS The subsurface conditions at the site were investigated by reviewing the available published information for the site geologic characteristics and by drilling five test borings at the locations shown on the Boring Location Plan, Figure 1 in the Appendix. Shelby tube samples and standard penetration test samples were obtained in the subsurface soil strata. The underlying shale bedrock was cored at one location using conventional NX sized rock coring equipment. Further discussion on the test borings can be found in Section 3.2 of this report. 3.1 General Area Geology According to available regional geologic information, the site is located within an area underlain by the lower Woodbine Geologic Formation of Cretaceous age. The lower Woodbine consists primarily of interbedded sandstone and shale layers with some sand 2 and clay layers. The sandstone can be very thinly to massively bedded with some beds of ironstone. The clays are slightly to very sandy and primarily red, brown and gray. 3.2 Soil Prof'fle In general, within the maximum 49-foot depth explored, the subsurface materials were found to consist primarily of probable fill and natural clay, silty clay and silty sand soils. These natural sandy and clayey soils are depositional materials consistent with those of the Woodbine Formation. The general stratigraphy and characteristics of the soil materials encountered within the test borings initiated for this exploration are summarized as follows: Depth, feet Description 0 to 1.5-2.0 PROBABLE FILL, Brown, tan, reddish brown and dark (Borings TH-2, gray, soft to stiff, SANDY CLAY and CLAY TH-4 and TH-5) Unified Soil Classification: CL,CH Moisture Content: 15 to 30% Liquid Limit: 33 Plastic Limit: 14 Plasticity Index: 19 0-2.0 to 7.0-13.0 Dark gray to grayish brown, medium stiff to very stiff, CLAY Unified Soil Classification: CH Moisture Content: 28 to 32% Liquid Limit: 75 Plastic Limit: 26 Plasticity Index: 49 7.0-13.0 to 17.0-18.0 Light gray and tan, very stiff to hard, SILTY CLAY to CLAY with trace calcareous deposits Unified Soil Classification: CL Moisture Content: 20 to 28 % Liquid Limit: 35 Plastic Limit: 15 Plasticity Index: 20 Unconfined Compressive Strength: 2.1 to 2.4 tsf 17.0-18.0 to 38.0 Light tan and tan, medium dense to dense, fine to medium coarse SILTY SAND with trace small gravel Unified Soil Classification: SM Moisture Content: 5 to 20% Standard Penetration Resistance: 15 to 82 blows per 12 inches penetration 38.0 to boring Dark gray SHALE termination depth Moisture Content: 16 to 17% Unconfined Compressive Strength: 16.1 to 25.9 tsf Based on the test results and our experience in the site area, the upper clay soils at the site are regarded as highly plastic and therefore are considered potentially highly expansive. 3.3 Groundwater Conditions Continuous flight and standard hollow stem augers were used to advance the test borings during the field activities for this exploration. Groundwater was indicated on the drilling tools at boring locations TH-i, TH-2 and TH-3 at depths ranging from 22 to 23 feet below the ground surface. Upon completion of the borings, the groundwater levels were measured at depths of 18 and 21 feet below the ground surface at locations TH-3 and TH- 1, respectively. Due to the introduction of water into the boring for the rock coring activities, within TH-2, an accurate measurement of the groundwater level after completion of the rock core was not possible. The borings drilled for this study were backfilled with the drill cuttings immediately upon completion. 4 The true groundwater level at the site could only be determined after several days observation in a cased monitor well. The clayey and sandy soils encountered at the site are generally regarded as slightly permeable to moderately impermeable and exhibit a slow to moderate response to groundwater movement. The predominant path of groundwater seepage appears to be within a silty sand layer approximately 18 to 20 feet below the existing ground surface. Groundwater may also be encountered within permeable sand layers closer to the surface. However, the groundwater level at the site is anticipated to fluctuate seasonally depending on the amount of rainfall, prevailing weather conditions and subsurface drainage characteristics. Further details concerning the subsurface materials and groundwater conditions encountered can be obtained from the laboratory test results and boring logs included in the Appendix of this report. 4.0 DESIGN RECOMMENDATIONS The following design recommendations have been developed on the basis of the previously described project characteristics and subsurface conditions. If there is any change in the project criteria, a review should be made by this office to determine if modifications in the recommendations will be required. 4.1 General Considerations The upper natural clayey soils encountered at the site were found to be highly plastic and are considered highly expansive. These soils were found to have natural moisture contents slightly above their respective plastic limits and a consistency of medium stiff to very stiff. These soils are expected to experience vertical movements as a result of soil moisture content changes which are anticipated beneath areas of the site covered by the proposed building floor slab and pavement. Based on the depths of the clays, the plasticity indices, the moisture contents, and the laboratory free swell results of the soils 5 tested, it is estimated that a total potential vertical rise (PVR) of up to 3 inches or slightly more could occur beneath the proposed building slab if it is constructed at existing grade. This potential vertical rise is based upon current conditions and can be used for design purposes if construction takes place within the next 2 to 3 months. The potential vertical rise could increase to 4 to 5 inches or greater if construction proceeds during or at the end of the dry summer season. Foundation Alternatives Several foundation alternatives were considered for this project to support the proposed fire station structure. These consisted of the following: 1. Drilled and underreamed (belled) piers bearing in silty clay to clay soils at depths of 14-15 feet below the existing ground surface. 2. Drilled straight shaft piers extending into an underlying competent bedrock strata. The light gray and tan silty clay to clay layer can be used to support the proposed fire station. Care should be taken not to penetrate the silty sand layer located immediately beneath this beating strata. Competent shale bedrock was encountered in test boring TH-2 at a depth of 38 feet below the ground surface. Therefore, either of these foundation systems could be used to adequately support the fire station building. Based upon the depth to the shale bedrock, we feel that the site is best suited for utilizing a drilled and underreamed (belled) pier foundation system bearing on the light gray and tan silty clay to clay materials. Recommendations for the design of drilled and underreamed piers at this site are provided in Section 4.2 of this report. Floor Slab Alternatives It has been our past experience that the floor slab for structures of this type are generally designed to withstand 1 inch of total movement or less. Therefore, we feel that the soil related 6 movements as described previously after grading are excessive for consideration of slab-on-grade construction at this site unless improvement of the underlying soils is performed. To reduce the swell potential and variability of the soil conditions beneath the proposed building location, special site improvements must be performed beneath the floor slab to reduce the potential vertical movements to 1 inch or less. ATEC evaluated several different options to reduce the soil movements to 1 inch or less after construction. These consisted of the following: 1) Undercutting of existing soil, removing the soils from the building pad area, and replacement with select fill to final subgrade. 2) Utilizing a combination of lime-slurry pressure injection of the building subgrade soils and a lesser depth of select fill than would be required in option 1. Option 1 consists of undercutting the existing clayey soils and removing them from the building area. The resulting excavation would then be backfilled with well compacted select fill brought in from off site. Based on our calculations, the depth of select fill below the existing ground surface required to reduce potential vertical rise movement to 1 inch or less was approximately 6 feet at the site. Option 2 consists of constructing the building pad to an elevation of approximately 2.5 feet below the final ground surface elevation. The exposed pad would then be injected with a minimum of 2 lime slurry and 2 water injections to a total depth of 7 feet below the exposed pad. This lime slurry and water injection process would be performed as an attempt to pre-swell the remaining expansive clay soils. Upon successful completion of the injection process (to be determined by laboratory testing), the building pad would be filled with a layer of non-expansive select fill soil up to the proposed finished floor subgrade elevation. For the purpose of our evaluation, we have assumed that the final finished floor subgrade surface would be at or near the existing ground surface. 7 Recommendations for option 1, cut and fill only, are provided in section 4.3.1 of this report. Recommendations for option 2, lime slurry/water injection, are provided in section 4.3.2 of this report. 4.2 Drilled Shaft and Grade Beam Foundation Systems Once the site grading operations are complete, our findings indicate that the structural frame and walls for the proposed fire station can best be supported by a system of drilled shafts. Following are our recommendations for design of drilled and underreamed (belled) shaft foundations. 4.2.1 Underreamed (belled) Shaft Foundations The shafts should be brought to bear in the light gray and tan silty clay to clay soils at a depth of 14-15 feet below the existing ground surface elevation for bearing capacity purposes. The presence of a silty sand layer was observed in the three deep borings at depths just below the recommended beating depth. Some field adjustment in the bearing depth may be required in order to properly construct the underream excavation. At the first sign of any silty sandy soils being encountered, the drilled shaft should be stopped and the underream constructed. A minimum bearing depth of 14 feet below the existing ground surface is recommended. Bell to shaft diameter ratios of between 2.5 and 3 to 1 should be maintained for these drilled shaft excavations. The shafts should be dimensioned based on a net allowable end bearing pressure of 5.0 kips/square foot. A minimum center to center spacing of 3.0 times the largest bell diameter is recommended for the piers. 4.2.2 Uplift Considerations and General Design Reconunendations Based on the proposed construction and depending on the soil conditions below the proposed structure, the drilled shafts will need to be designed to accommodate uplift 8 pressures due to expansive soil conditions. Swelling clays and overlying soils in contact with the shaft perimeters will cause such uplift pressures to develop in upward skin friction. The magnitude of uplift pressure due to soil swell along the drilled shafts is estimated not to exceed about 1.0 kips/square foot. The soil swell pressure should generally act over the portion of shafts above the underream encountering the highly expansive clay soils to a total depth of 10 feet below the finished grade. The uplift resistance for underreamed shafts bearing at the recommended bearing depth can be achieved by underreaming the bottom of the shafts. Again, it is recommended that the underreamed portion be at least 2.5 but no more than 3 times the diameter of the shaft. All shafts should be adequately reinforced due to uplift pressures caused by either potential swelling soils and/or structural loading conditions. Reinforcing steel should extend the full length of the shaft. Provided the underreamed piers are designed as outlined above, total settlement beneath properly constructed foundation elements is estimated to be minor, generally on the order of 0.5 inch or less. Such settlement normally occurs as elastic deformation during construction. During installation of any piers, the cross section of the shafts should not be allowed to increase at the ground level. A "mushroom" at the top of the shafts could create uplift pressures related to soil swelling which could be detrimental to the shafts at some locations. Any pier caps over expansive clays, if required, should be constructed over a void space. Also, all grade beams constructed over clays should be formed with a nominal 6-inch void with soil retainers using cardboard box forms or other equivalent materials made for this purpose. On-site clay soils should be used to backfill around perimeter grade beams shortly after removing concrete forms. The backfill should be 9 well compacted to prevent water from entering the void space during or after construction and inducing swelling of the underlying soils. 4.3 Floor Slab on Improved Subgrade Material As stated in Section 4.1, due to the presence of highly expansive clay soils present within the proposed construction area, the proposed new fire station will be subjected to upwards of 3 inches or slightly more of potential vertical movement if construction proceeds within the next 2 to 3 months. 4.3.1 Cut/Fill Only (Option 1) In order to reduce the total potential vertical movements to a more desirable design level on the order of 1.0 inch or less, the following subgrade improvements are recommended for the proposed fire station structure: 1) Existing vegetation should be stripped and removed from the site. 2) The building area should be excavated as necessary to a minimum depth of 6 feet below the existing site grades. The expansive clay soils excavated should be removed from the site, or stockpiled on the site for use as grade raise fill outside the building foundation area. 3) Following excavation and prior to select fill placement, the exposed pad should be proofrolled to expose any weak, soft, wet, or otherwise unsuitable soils. Proofrolling should be performed as described in Section 5.1 of this report. 4) Following proofrolling, the exposed subgrade clay soils should be scarified to a depth of 6 inches, wetted to within + 3% of optimum moisture content and compacted to at least 95 % of the Standard maximum dry density for the subgrade materials (ASTM D-698 Method A). 10 5) Select fill soil should be used as the final 6 feet of fill within the building area. Select fill should be brought in from off site and placed in 8-inch thick horizontal lifts within the building area, moisture conditioned to within -3 % to + 3 % of optimum moisture content and compacted to 95 % of the Standard maximum dry density for the select fill materials. Select fill should be placed in accordance with the recommendations outlined in Section 5.3. 6) Filling should then proceed up to finished subfloor grade. The exposed surface of the select fill soils should be kept moist during shaft drilling operations and be moistened just prior to placing the floor slab. Preferably the select fill should not extend outside the limits of the structure in areas which will not be sealed with flatwork or pavement. When placing the select fill, care should be taken to avoid water ponding in the select fill layer. This could cause post construction movements which exceed the estimated values. Care must be taken to prevent landscape watering, surface drainage, leaking utility lines or other sources of water from entering the select fill. 4.3.2 Lime Slurry/Water Injection (Option 2) As described in Section 4.1, recommendations for preparing the building pad subgrade utilizing option 2 are provided in this section. Option 2 consists of stripping the existing surficial soils within the proposed building pad and five feet outside the building limits to a depth of 2.5 feet below the proposed finished floor subgrade elevation. The entire exposed pad would then be injected to a total depth of 7 feet below the exposed pad elevation with a minimum of 2 lime slurry and 2 water injection passes. The purpose of the lime slurry and water injections would be to provide the clay soils with free moisture in an attempt to pre-swell the clay soils. Upon successful completion of the water injections (to be determined by laboratory testing) the exposed pad would be filled with a layer of non-expansive select fill soil imported from off-site. Filling would proceed up to the finished floor subgrade elevation. 11 We recommend that a minimum of two lime and two water passes over the entire building area be performed initially. It is possible that additional passes with water may be necessary, especially if construction proceeds during or just after dry summer months. It is our opinion that the construction budget should have a contingency for additional passes. The success of the injection procedure depends upon the ability to inject lime slurry and water under pressure into the seams and fissures in the otherwise impervious clay soils. Details concerning the injection depths, associated construction procedures and confirmation testing are described in Section 5.3 and in the Appendix. Upon satisfactory completion of the injection process, the upper six inches of the subgrade should be scarified and properly compacted. In an attempt to provide a uniform bearing material for the foundation slab and further reduce potential floor slab movement, then following subgrade preparation, non-expansive select fill should be installed as described earlier to achieve the desired final design grade. If all of the above recommended improvements are successfully performed, and drainage considerations described below are maintained, then the potential post construction foundation slab moisture induced movements should be limited to 1-inch or less. Differential movements will be on the order of 0.75 inch over the length of the building. The horizontal limits of select fill should be limited to those areas where a reduction in potential soil movements is desired. These may include paving and flatwork areas directly adjacent to the structure such as at doorways and entrances. The select fill should not extend outside the limits of the building in areas which will not be sealed with flatwork or pavement. A description of select fill, its placement and compaction requirements are provided in Section 5.4 of this report. When constructing select fill, care should be taken to avoid water ponding in the select fill layer. This could cause post construction movements which exceed the estimated values. Care must be taken to prevent landscape watering, surface drainage, leaking utility lines or other sources of water from entering the select fill. 12 4.3.3 General Recommendations Due to the weight of the fire trucks that will be used at 'maintained at the fire station, ATEC recommends that the floor slab portion of the building, where the trucks are parked, be an 8-inch thick reinforced concrete section. The remaining area of the building can be a conventional thickness for this type of building. 4.4 Pavement Design We anticipate that once the site grading is complete, moderately expansive fill and highly expansive natural clay soils will be exposed at the surface on the majority of the site outside building areas. Because these soils exhibit a potential for shrinking and swelling, it is likely that pavements constructed on-site will be subject to movement from the soils below. The result of these movements causes distress within the pavement section which typically leads to higher maintenance frequency and costs than for pavements constructed over non-expansive clays. Some differential movements of the expansive subgrade soils should be anticipated once grading is completed. Therefore, the pavement surfaces should be finished and sloped for positive drainage. Good perimeter drainage around the pavements is also recommended. Both total and differential movements should be taken into consideration at locations where pavements transition into structures. Generally, it is common practice to lime stabilize the upper 6 to 8 inches of subgrade soil beneath pavements within this area. The purpose of this stabilization is not to reduce the movements beneath the pavements, but instead to improve the bearing value of the pavement subgrade soils and provide uniform soil conditions on which to construct the pavements. To reduce the movements beneath the pavement areas generally requires additional pavement subgrade preparation in conjunction with the pavement design. 13 For this project, it is recommended that once the final grade haq been established, representative samples of the subgrade materials be obtained for laboratory testing. Lime - series tests should be performed on the soil samples to determine the optimum lime concentration to reduce the Plasticity Index to 15 or below and to raise pH levels to a minimum of 12.4. The exposed surface of the soils should be scarified to a depth of at least 6 inches and mixed with the required amount of lime (determined in the lime - series tests) in accordance with the procedures described in the Standard Specifications for Public Works Construction, North Central Texas, Item 4.6, prepared by the North Central Texas Council of Governments (NCTCOG). For estimating purposes only, 6 percent hydrated lime is commonly used. The sealed soil-lime mixture should be allowed to cure for a minimum time of 48 hours, then be remixed. The remixing and pulverization operation, as described in NCTCOG Item 4.6, should proceed until the soil is uniformly broken down and meets the gradation limits provided in that specification. The resulting mixture should then be brought to near optimum (optimum to plus 3 percentage points above) moisture condition and uniformly compacted to a minimum of 95 percent of standard Proctor (ASTM D-698) density. The compacted material should then be covered immediately with paving or kept moist until the paving is placed. In all areas where hydrated lime is used to stabilize the subgrade soils, routine gradation tests should be performed at a rate of one test every 10,0t30 square feet of paving area and at least one test per day. Gradation percentages outlined in NCTCOG Item 4.6 should be utilized. These tests will confirm that the material has been adequately broken down. Should any areas be out of conformance on these tests, then additional lime or remixing must be performed to bring the soil into compliance for the 10,000 square feet area represented by the deficient tests. Field density testing should also be performed at the above recommended frequency to confirm proper compaction. 14 The following reinforced concrete pavement sections have been developed based on the noted traffic loading conditions for consideration at this site. Light Traffic (automobiles, occasional light trucks, parking arms) 5.0 in. Reinforced concrete 6.0 in. Lime stabilized and compacted subgrade Heavy Traffic (fire lanes, service drives, fire engine traffic areas) 7.0 in. Reinforced concrete 6.0 in. Lime stabilized and compacted subgrade All concrete use on site should exhibit the following properties: Compressive Strength @ 28 days ...................... 3500 psi min. Air Content ........................................ 4 - 6% A relatively close joint spacing of 15 feet is preferred. Local area practice often includes the use of No. 3 reinforcing steel bars in each direction at spacing of 12 to 24 inches with an 18-inch spacing being commonly used. Expansion joints should be sawed as soon as the concrete will allow. If construction joints are provided, these joints should be keyed. Proper design and sealing of joints will help minimize moisture in-flow in the subgrade. A properly graded and drained pavement subgrade to minimize the trapping of water under the pavement must also be provided. Proper concrete finishing and curing practices must be employed. All paving materials should comply with the Texas Department of Transportation Standard Specifications for Construction of Highways, Streets and Bridges, Item 360, 1993. Loading (traffic) must not be allowed until the concrete has reached 75 percent of its design strength. The pavement sections described above are considered suitable for general purpose usage for the anticipated subgrade conditions. A comprehensive analysis of the pavement 15 system was not within the scope of work for this exploration. This analysis would include consideration of traffic loads, frequency, subgrade drainage, design life and the overall economics. An aggressive maintenance program to keep joints and cracks sealed to prevent moisture infiltration will help extend the pavement life. 4.5 Drainage Positive surface drainage must be incorporated into the final grading plan to reduce seasonal variations in moisture content of the foundation soils. All pavements and sidewalks must be sloped away from the proposed fire station building to prevent ponding of water near the foundation. The foundation slab should be set at a high enough level to permit a final exterior downward grade slope of at least 1 foot (vertical) to 10 feet (horizontal) for a distance of at least 5 feet (but preferably 10 feet) away from the building. Roof downspouts should discharge at least 3 feet away from the foundation slab. We recommend that area paving or exterior flatwork extend to the building lines, if possible, rather than have planters or other open areas adjacent to the structure. If planters are located adjacent to the building, they should be self-contained to eliminate a possible source of moisture gain or loss to the soils beneath the building slab. All trees should be a minimum of one-half their mature height away from the building or pavement edges to reduce potential for moisture fluctuations in the foundation soils. Careful control of irrigation water within planters is essential. No water must be allowed to percolate down to any remaining underlying potentially active soils below the building. Therefore, we recommend that the exposed backfill soils extending beyond the building lines be capped with a 18 inch thick cover of well compacted, impervious clay with a plasticity index between 15 and 25 or be covered with pavements. The purpose of the 16 clay cap or pavements is to minimize potential moisture losses or gains beneath the building. 5.0 GENERAL CONSTRUCTION PROCEDURES AND RECOMMENDATIONS It is possible that variation in subsurface conditions will be encountered during construction. In order to permit correlation during construction between the test boring data and the actual subsurface conditions encountered during construction, it is recommended that a registered geotechnical engineer or his representative be retained on a continuing basis to perform observations during construction. Some construction problems, particularly as to degree or magnitude, cannot be anticipated until the course of construction. The recommendations offered in the following paragraphs are not intended to limit or preclude conceivable solutions, but rather to provide the client with our observations based on our experience and our understanding of the project characteristics and subsurface conditions. 5.1 Site Preparation and Grading In general, site preparation should include necessary stripping of vegetation and proofrolling. After excavation and prior to placing any fill, we recommend that the exposed subgrade be carefully inspected by proofrolling to help compact pockets of loose soil and expose additional areas of weak, soft, or wet soils. This proofrolling will be critical in areas of the site which may have been previously filled such as those observed in borings TH-2, TH-4 and TH-5. This must be accomplished prior to placing any grade raise fill and drilling any shafts. The proofrolling operation must be performed under the observation of a qualified geotechnical engineer. Proofrolling consists of rolling the entire subgrade with a heavily loaded tandem axle dump truck or other approved equipment capable of appl)/ing similar 17 wheel loads. Any soft, wet or weak fill or natural soils disclosed by proofrolling should be removed and replaced with well compacted material as outlined in Section 5.3. Care should be exercised during the grading operations at the site. The traffic of heavy equipment, including heavy compaction equipment, may create a general deterioration of the shallower soils. Therefore, it should be anticipated that some construction difficulties could be encountered during periods when these soils are saturated and that it may be necessary to improve, remove or simply stay off of the saturated soils. 5.2 Drilled Shaft Excavations All drilled shaft excavations must be carefully observed to confirm that foundation elements will bear on satisfactory materials. Materials exposed in the base of all satisfactory shaft excavations should be protected against any detrimental change in condition. Surface runoff water should be drained away from the drilled shaft excavations and not be allowed to collect. All concrete for drilled shafts should be placed the same day the excavation is made and not more than 2 hours after completion of drilling. All drilled shafts should be at least 1.5 feet in diameter to facilitate clean out of the base and proper observation. Based upon the groundwater conditions observed at the time of our field study, it is possible that minor groundwater seepage into the shaft holes may occur. It is anticipated that by having concrete ready on-site to pour into the shaft holes within 120 minutes upon completion and setting of steel reinforcement, that the shafts can be completed without pumping water. If the groundwater accumulation within any shaft hole exceeds 1.5 inches, the water should be removed by pumping prior to placing concrete in the shaft. It is also recommended that all shaft concrete be placed through a tremie to minimize the potential for aggregate segregation. 18 5.3 Lime Slurry and Water Pressure Injections If Option 2 for the soil improvement below the floor slab is selected, then after excavation and following proofrolling, the proposed building area and five feet outside the building limits should be pressure injected to a depth of at least seven feet. The purpose of this procedure is to partially pre-swell the existing soils and to introduce a water-lime mixture that will aid in controlling natural variations in moisture content of the clay soils. Satisfactory completion of the injection process will have been achieved when the desired moisture content and free swell potential have been reached, based on results of additional field and laboratory soil tests. A total of four pressure injection passes (2 lime slurry and 2 water) must be made initially. The number of additional water injections required to achieve the desired moisture content will depend upon the condition of the clays prior to injection. If construction of the foundation slabs is initiated after a prolonged dry period, as many as two more water injections may need to be performed. Soil samples must be obtained from test holes taken during this procedure to confirm that a satisfactory moisture level is achieved. As described in Section 4.4, there is some risk that the injection process may not elevate the soils to the proper moisture content. Additional select fill would then be necessary to achieve the design potential vertical rise of 1.0 inch. The subgrade surface must not be allowed to dry during or following the injection process. Maximum benefits of this procedure can only be achieved if the entire process is carefully inspected and monitored by a qualified representative of the project geotechnical engineer. Guideline construction specifications for the lime and water slurry pressure injection process are provided in the Appendix. Immediately following successful completion of the injection process, the subgrade should be scarified, brought to proper moisture content and compacted. A uniform 19 thickness of select fill should then be installed within the building limits to achieve finished floor subgrade elevation. Specific recommendations on placement, compaction and extent of the select fill is described in Sections 4.3.1 and 5.4. Select fill should comply with the recommendations outlined in Section 5.4 for select non-expansive soil. 5.4 Fill Placement and Compaction All soil materials used as fill should be free of decomposable or otherwise deleterious material. All on-site or fill soils with a plasticity index greater than 15 can be used as grade raise fill outside building foundation areas. All clay soils should be compacted to a dry density of at least 93 percent, but not exceeding 98 percent, of the Standard maximum dry density (ASTM D-698 Method A) outside the building foundation area. The compacted moisture content of the clays during placement should be at optimum and not exceeding 6 percentage points above the optimum moisture content. Recommendations for preparation and compaction of soils within the upper 6 inches below the pavement sections are discussed in Section 4.4. Materials brought in from off-site and used as select fill beneath the building should consist of a uniform, homogeneous,non-expansive sandy clay or clayey sand soil with a liquid limit (LL) between 20 to 35 and have a plasticity index (PI) of not less than 5 or greater than 15. All select fill should be moisture processed within -3 to +3 percentage points of the materials optimum moisture content and compacted to a dry density of at least 95 percent of the Standard maximum dry density. Compaction should be accomplished by placing the fill in 6 to 8 inch thick loose lifts and compacting each lift to at least the specified minimum dry density. It is imperative that the fill materials not exceed four inches in maximum size. If larger fragments or clods are encountered during grading, then these clods must be broken down prior to final placement and compaction in the fill. 20 In order for the fill materials to perforTM as intended, the fill material must be placed in a manner which produces a good uniform fill compacted within the density and moisture ranges outlined in the preceding paragraphs. Density testing must be performed on fill soils to confirm this performance as construction progresses. In the building area fills, we recommend that each lift be tested at a frequency of no less than 1 test per lift per each 5,000 square feet. In remaining areas on-site, a testing frequency of 1 test per lift per each 10,000 square feet should be sufficient. 5.5 Groundwater As described in Section 5.2, minor groundwater seepage may occur in random drilled shaft excavations. By placing steel reinforcement and concrete in the shaft holes within 120 minutes after completion, groundwater accumulation is anticipated to be minor and no pumping would be required. If the groundwater accumulation depth reaches above 1.5 inches within any open shaft hole, the water should be removed by pumping prior to placing concrete. Any groundwater in shallow excavations should be removed by pumping. 6.0 QUALIFICATIONS OF RECOMMENDATIONS Our evaluation of foundation design and construction conditions has been based on an understanding of the site and project information and data obtained during our field investigation. The general subsurface conditions utilized have been based on interpolation of the subsurface data between the borings. Regardless of the thoroughness of a subsurface investigation, there is always the possibility that conditions between borings will be different from those at the boring locations, that conditions are not as anticipated by the designers, or that the construction process has altered the soils conditions. Therefore, experienced geotechnical engineers or their representative should inspect the earthwork and foundation construction to confirm that the conditions anticipated in design actually exist. Otherwise, we assume no responsibility for construction compliance with the design concepts, specifications or recommendations. 21 In our experience, ATEC has found it beneficial that once the final construction plans and specifications have been completed, that we be allowed to review such plans and related documents. The purpose of the review will be to confirm that the design documents and details are consistent with the recommendations included in this report. The design recommendations presented in this report have been developed on the basis of the previously described project characteristics and subsurface conditions. If there is any change in these project criteria, including project location on the site, a review should be made by this office to determine if any modifications in the recommendations will be required. The findings of such a review should be presented in a supplemental report. The nature and extent of variation between the borings may not become evident until the course of construction. If significant variations then appear evident, it will be necessary to reevaluate the recommendations of this report after performing on-site observations during the construction period and noting the characteristics of any variation. However, only minor variations that can be readily evaluated and adjusted for during construction are expected. Our professional services have been performed, our findings obtained and our recommendations prepared in accordance with generally accepted geotechnical engineering principles and practices. This warranty is in lieu of all other warranties either expressed or implied. This company is not responsible for the conclusions, opinions or recommendations made by others based on these data. 22 As the client of a consulting geot~hnical engineer, you MOST GEOTECHNICA~ FINDINGS ARE should know that site subsurface conditions cause more PROFESSIONAL JUDGMENTS construct/on problems than any other factor. ASFF_/T'he Site ~xploration identifies actual subsurface conditions Association of Engineering Finns Practicing in the only at those points where samples are taken. The data Geosdences offers the following suggestions and were extrapola~'ed by your ~eatechnicat engineer who observations to help you manage your dsks. t~en applied judgment to render an opinion about overall subsurface conditions. The actual interface A (;EOTECHNICAL ENGINEERING P,,EPORT IS BA~ED between materials may be far more gradual or abrupt ON A UNIOUE SET OF PROJECT-SPECIFIC FACTORS than your report indicates. A~ual conditions in areas Your geotechnicaI engineering report is based on a not sampled may differ from those predicted in your subsurface exploration plan designed to consider a report. While nothing can be done to prevent such unique set of project-specific factors. These factors situations, you and your geotechnicaI engineer can L'ypicaily include: the general nature of the structure together to hetp minimize their impact. Retaining your involved, its size. and configuration; the location of the geotechnical engineer to obse.we construction can be structure on the site; other improvements, such as particularly beneficial in this respect. access roads, parking lots. and underground utilities~ and the additional dsk created by scope-of-service A REPORT'S RECOMMENDATIONS limitations imposed by the client. To help avoid costly CA/N ONLY BE PRELIMINARY problems, ask your geotechnical engineer to evaluate The construction recommendations included in your how factors that change subsequent to the date of the geotechnical engineer's report are preliminary, because report may affect the report's recommendations, they must be based on the assumption that conditions revealed through se!ective exploratory sampling are Unless your geotechnical engineer indicates otherwise, indicative of actual conditions throughout a site. do not use your geotechnic~l engineering report: Because actual subsurface conditions can be discerned only during earthwork, you should retain your geo- · when the nature of the proposed structure is technical engineer to observe actual conditions and to changed, for example, if an office building will be finalize recommendations. Only the geotechnical erected instead of a parking garage, or a refrigerated engineer who prepared the report [s ~ully familiar with warehouse will be built instead of an unret:rigerated the background information needed to determine one: whether or not the report's recommendations are valid · when the size, eIevation, or configuration of the and whether or not the contractor is abiding, by appli- proposed structure is altered: cable recommendations. The ~eotechnical engineer who · when the location or orientation of the proposed developed your report cannot assume responsibility or structure is modified; liability for the adequac/of the report's recommenda- · when there is a change of ownership: or tians if another party is retained to observe construction. · for application to an adiacent site. GEOTEC, J-INiCAL SERVICES ARE PERFORMED Geotechnical engineers cannot accept responsibility for FOR SPECIFIC PURPOSES AND PERSONS problems that may occur if they are not consulted after Consulting geotechnica[ engineers prepare reports to ~actors considered in their report's development have meet the spedfic needs of specific individuals. A report changed, prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. SUBSURFACE CONDITIONS CAN CHANGE Unless indicated otherwise, your geotechnical engineer A geotechnical engineering report is based on condi- prepared your report expressly for you and expressly ~or tions that existed at the time of subsurface exploration, purposes you indicated. No one other than you should Do not base construction decisions on a geotechnica[ apply this report for its intended purpose without first engineering report whose adequacy may have been conferring, with the geotechnical engineer. No party affected by time. Speak with your geotechnical consult- should apply this report for any purpose other than that ant to learn if additional tests are advisable before originally contemplated without first conferring with the construction starts Note. too. that additional tests may geotechnical engineer. be required when subsurface conditions are affected by construction operations at or adjacent to the site. or by GEOENVIRONMENTAL CONCERNS natural events such as floods, earthquakes, or ground ARE NOT AT ISSUE water fluctuations. Keep your geotechnical consultant Your g,eotechnical engineering report is not likely to apprised of any such events, relate any findings, conclusions, or recommendations about the potential for hazardous materials existing at mates ,;vas not one of :he specific purposes for which it the site. The equipment, techniques, and personnel was prepared, tn other words, whiIe a contractor may used to perform a geoenvironmental exploration differ gain important knowledge from a report prepared for substantially from those applied in geotechnical another party, the contractor would be well-advised to engineering. Contamination can create major dsks. If discuss the report with your geotechnical engineer and you have no information about the potential for your to perform the additional or alternative work that the site being contaminated, you are advised to speak with contractor believes may be needed to obtain the data your geotechnical consultant for information relating to specifically appropriate for construction cost estimating geoenvironmental issues, purposes.) Some clients believe that it is unwise or unnecessary to give contractors access to their geo- A GEOTECHNICAL ENGINEERING REPORT IS technical engineering reports because they hold the SUBJECT TO MISINTERPRETATION mistaken impression that simply disclaiming responsi- Costly problems can occur when other design profes- bility for the accuray/of subsurface informal:ion always sianals develop their plans based on misinterpretations insulates them from attendant liability'. Providing the of a geotechnical engineering report. To help avoid best available information to contractors helps prevent misinterpretations, retain your geotechnical engineer to costly construction problems. It also helps reduce the work with at. her project design professionals who are adversarial attitudes that can aggravate problems to affected by the geotechnical report. Have your geotech- disproportionate scale. nical engineer explain report implications to design professionals affected by them, and then review those READ RESPONSIBIUTY CLAUSES CLOSELY design professionals' plans and specifications to see Because geotechnical engineering is based extensJve!y how they have incorporated geotechnical factors, on iudgment and opinion, it is far less exact than other Although certain other design professionals may be faro- design disciplines. This situation has resulted in wholly Jliar with geotechnica[ concerns, none knows as much unwarranted ctaims being lodged against geotechnical about them as a competent geotechnical engineer, engineers. To help prevent this problem, geotechnical engineers have developed a number of clauses for use in BODING LOGS SHOULD NOT BE SEPARATED their contracts, reports, and other documenLs. Responsi- FROM THE I~E:PORrT bility douses are not exculpatory clauses designed to Geotechnical engineers develop final bodng logs based transfer geotechnical engineers' liabilities to other upon their interpretation of the field Iog, s (assembled by parties. Instead. they are definitive cfauses that identify site personae!) and laboratory evaluation of field where geotechnical engineers' responsibilities begin and samples. Geotechnical engineers customarily include end. Their use helps all parties involved recognize their only final bodng logs in their reports. Final bodng logs individual responsibilities and take appropriate action. should not under any circumstances be redrawn for Some of these definitive clauses are likely to appear in inclusion in architectural or other design drawings, your geotechnic, nl engineering report. Read them because drafters may commit errors or omissions in the ctosely. Your geotechnical engineer will be pleased to transfer process. Although photographic reproduction give full and frank answers to any questions. eliminates this problem, it does nothing to minimize the possibili~ of contractors misinterpreting the logs during ,m~JELY ON TIIE GEOTECHNICAL ENGINEER bid preparation. When this occurs, delays, disputes, and FOR ADDITIONAL ASSISTANCE unanticipated costs are the all-too-frequent result. Most ASFE-member consulting geotechnical engineer- ing firms are familiar with a vadety of techniques and To minimize the likelihood of bodng log misinterpreta- approaches that can be used to help reduce dsks for all lion, give contractors ready access to the complete parties to a construction proiect, from design through geotechnical engineering report prepared or authorized construction. Speak with your geotechnical engineer not for their use. Ill access is provided only to the report only about geotechnical issues, but others as weil, to prepared for you. you should advise contractors of the learn about approaches that may be of genuine benefit. report's limitations, assuming that a contractor was not You may also wish to obtain certain ASFE publications. one of the specific persons for whom the report was Contact a member of ASFE of ASFE for a complimentary prepared and that developing construction cost esti- directot'y, of ASFE publications. PRO FESSIONAL FIRMS PRACTICING IN THE GEOSCIENCES 881 I COLESVILLE ROAD/SUITE G 106/SILVER SPRING, M D 209 [ 0 TELEPHONE: 301/565-2733 FACSIMILE: 30i/589-2017 CoDyr:,]h[' Igc~2 by '~S;'.~. lac Unless ASF-~ gran:s $tse';.lfi¢ ;ermissfan [o do so. duplication of :h~s dcc:.men: by any means ~ha~soever ~s e.x~.re$~:'/ Droh,bl:.'d B PCO 5g 2.,-~ ':j ~M APPENDIX Figure 1 - Boring Location Plan Field Investigation Procedures Laboratory Investigation Procedures Table 1 - Free Swell Test Results Record of Subsurface Exploration Sheets (Boring Logs) Key to Soil Symbols and Classification Guideline Specifications for Lime Slurry and Water Pressure Injection FIELD INVESTIGATION PROCEDURES Using standard continuous flight and hollow stem auger drilling equipment, a total of five test borings were drilled for this investigation at the approximate locations shown on the Boring Location Plan, Figure 1, included in this Appendix. The number and general location of the borings were chosen by Phillips Swager Associates, the project architect. The depths of the borings were selected by ATEC Associates, Inc. (ATEC). The test boring locations were staked in the field by an ATEC representative using standard taping procedures. Relatively undisturbed samples of the cohesive subsurface materials were obtained by hydraulically pressing 3 inch O.D. thin-wall tubes into the underlying soils at selected depths (ASTM D-1587). These samples were removed from the sampling tubes in the field and examined visually. One representative portion of each sample was sealed in a plastic bag for use in future visual examinations and possible testing in the laboratory. In addition, representative samples of the subsurface materials were obtained employing split- spoon sampling procedures (ASTM D-1586). Relatively disturbed samples were obtained at selected depths in the borings by driving a standard 2 inch O.D. split-spoon sampler 18 inches into the subsurface material using a 140 pound hammer falling 30 inches. The number of blows required to drive the split-spoon sampler the final 12 inches of penetration (N-value) is recorded in the appropriate column of the logs. Samples of the dark gray shale bedrock were obtained in one of the five test borings using conventional bix rock coring equipment. Each rock core sample was retained and transported to our laboratory in appropriate core boxes. Logs of all borings (Record of Subsurface Exploration Sheets) have been included in this Appendix. The logs show visual descriptions of the soil and rock strata encountered using the Unified Soil Classification System. Sampling information, pertinent field data, and field observations are also included. LABORATORY INVESTIGATION PROCEDURES The soil and rock samples were inspected and classified by a geotechnical engineer in accordance with the Unified Soil Classification System and the boring logs were edited as necessary. Natural moisture content tests (ASTM D-2216) and Atterberg limit tests (ASTM D-4318) were performed on selected samples to aid in classifying the subsurface materials and to determine the engineering characteristics of the materials. In addition, hand penetrometer strength tests were performed on selected soil samples. Results of all laboratory tests described above are provided on the accompanying boring logs. The expansive properties of the upper clay layer were further analyzed by performing one free swell test. The free swell test was performed by placing a selected sample in the consolidometer apparatus with a predetermined overburden pressure and allowing the sample to expand by absorbing water. When the sample exhibited very little tendency for further expansion, the final height was recorded and the percent swell and total moisture gain calculated. The result of this test is listed in Table 1 in this Appendix. Unconfined compressive strength tests (ASTM D-2166 and D-2938) were performed on selected soil and rock samples in order to evaluate the potential allowable bearing pressure design values for the clay soils and shale bedrock strata. The results of these tests are listed on the appropriate boring logs. GEOTECHNICAL EXPLORATION PROPOSED FIRE STATION Southwestern Boulevard Coppell, Texas 25-02-95-00091 Boring Depth. (fO Pressure, (tsf} Moisture, (%) Moisture, (%) Swell. (%} B-3 I 2-4 0.059 28.8 I 30.7 I 1.6 ATEC Associates, Inc. 11356 Mathi,- hue Dallas, Texas . ,2S RECORD OF (214) 556-2204 SUBSURFACE EXPLORATION Metro 263-1681 Client City of Col3pell, Texas Boring # TH-1 (Page 1 of 1) Architect Engineer Phillips - Swager Associates Job # 25-02-95-00091 Project Name PROPOSED FIRE STATION Drawn By CRF Project Location Southwestern Blvd/Coppell, Texas Approved By DPZ DRILLING and SAMPLING INFORMATION TEST DATA uate ~tarted ~1.-~-~1~ Hammer Wt. 140 lbs. Date Completed 4-3-95 Hammer Drop 30 in. Drill Foremen RDC Spoon Sampler OD 2.0 in. I- .__> Inspector Rock Core Dia. in. Client ID # 0122 Co. tinuous Tube OD N/A in. ~' ~ ~= d c~ O'o > . SOIL CLASSIFICATION =E ,= ~. ~. - , , SURFACE ELEVATION' ~ ¢3 ~ ~ Z~ ~ ~ :_c;~w. 50 ~o ~ :~.~' ;;~ ~;~._ Dark gray to gray, stiff, CLAY (CH) -- _ I ST 80 1.4 31.0 _ -medium stiff to stiff below 2' - - 2 ST 90 1.0 30.0 - -stiff below 4' - 5 3 ST 80 1.75 29.0 ;s ;e4e__ -grayish brown to tan and very stiff - - - below 7' _ -- 4 ST 90 2.5 29.0 _ ~ 10 13.0 ; Light gray and tan, very stiff, SILTY - CLAY to CLAY (CL-CH) with trace - 5 ST 100 2.4 3.75 107.8 23.0 _ small calcareous nodules 15 17.0 Light tan, fine, dense, SILTY SAND - - - (SM) - _ -- 6 SS 90 34 7.0 -- ~ 20 -tan, fine to medium coarse, with trace - ~ - - small gravel below 22' - _ -- 7 SS 10(~~ 39 13.0 - Bottom of test boring at 25' 25 SAMPLER TYPE GROUNDWATER DEPTH BORING METHOD SS - SPLIT SPOON-SPT ~ AT COMPLETION 21.00 FT. HSA- HOLLOW STEM AUGER ST - PRESSED SHELBY TUBE ~ AFTER HRS. FT. CFA- CONTINUOUS FLIGHT AUGERS RC - ROCK CORE · WATER ON RODS 22.00 FT. DC - DRIVING CASING THD - TEXAS HIGHWAY DEPARTMENT CONE -i- AT SURVEY FT. RW - ROTARY WASH CU - CUTTINGS HPA- HAND POWER AUGER CT - CONTINUOUS TUBE ATEC Associate_s, Inc. 11356 Mathig hue RECORD OF Dallaa, Texaa ~ ~.,.29 (214) 556-2204 SUBSURFACE EXPLORATION Metro 263-1681 Client Cit~ of Coppell, Texas Boring # TH-2 (Page 1 of 2) Architect Engineer Phillips - Swager Associates Job # 25-02-95-00091 Project Name PROPOSED FIRE STATION Drawn By CRF Project Location Southwestem Blvd/Coppell, Texas Approved By DPZ DRILLING end SAMPMNG INFORMATION TEST DATA uate Started 4-1 ~-~1~ Hammer Wt. 140 lbs. Date Completed 4-13-95 Hammer Drop 30 in. i · Drill Foremen RDC Spoon Samp~ OD 2.0 in. ~- *->- In.pector Rock Core Dia. 2.125 in. § '-~ [ ; .; .~.~ Boring Method "SA Shelby Tube OD 3.0 in. ,., · c,ent ~o # 0122 Continuous Tube OD N/A m SURFACE ELEVATION' ~ uJ C) ~ ~ - .c ¢:,- '; := · POSSIBLE FILL, brown, tan and dark - gray, soft, SANDY CLAY and CLAY - 1 STSO 0.4 20.0 _ .,.m_ .................... - 2.o _ _ Dark gray, stiff, CLAY (CH) _ 2 ST 102 1.5 32.0 _ -grayish brown below 4' - ~ 5 3 ST 90 1.5 31.0 - .brown with trace calcareous nodules - 4 ST 80 1.8 28.0 _ below 9' 10 12.0 CLAY (CL) with trace calcareous - - deposits - 5 ST 100 3.75 20.0 ~s=(- ~ 15 18.0 - (SM) - s ST 70~ S.0 _ 2O -tan, fine to medium coarse below 23' - a - 7 SS 100 39 -- ~ 25 -very dense with trace small gravel - - - below 27' - - -- 8 SS ! O0 82 -- SAMPLER TYPE GROUNDWATER DEPTH BORING METHOD SS - SPMT SPOON-SPT _~ AT COMPLETION FT. HSA- HOLLOW STEM AUGER ST - PRESSED SHELBY TUBE _~ AFTER HRS. FT. CFA- CONTINUOUS FUGHT AUGERS RC - ROCK CORE ~ WATER ON RODS 23.00 FT. DC - DRIVING CASING THD - TEXAS HIGHWAY DEPARTMENT CONE 't- AT SURVEY FT. RW - ROTARY WASH CU - CUTTINGS HPA- HAND POWER AUGER CT - CONTINUOUS TUBE ATEC Associates, Inc. 1 11356 Mathis ''"~ue RECORD OF Dallas, Texas ~ (214) 556-2204 SUBSURFACE EXPLORATION Metro 263-1681 clot City of Coppell, Texas Boring # TH-2 (Page 2 of 2) Architect Engineer PhilliDs - SwaQer Associates Job # 25-02-95-00091 Project Name PROPOSED FIRE STATION Drawn By CRF Project Location Southwestern Blvd/Coppell, Texas Approved By DPZ DRILLING and SAMPLING INFORMATION TEST DATA Date Started 4-13-95 Hammer Wt. 140 lbs. Date Completed 4-13-95 Hammer Drop 30 in. ~ · Drill Foreman RDC Spoon Sampler OD 2.0 in. I- ._-> Inspector Rock Core Dia. 2.125 in. ~, ._o , ~ Boring Method HSA Shelby Tube OD 3.0 in. ~. ~ <~ . ' E Client ID # 0122 Continuous Tube OD N/A in. ~ · · ~" ~ '5 SOIL CLASSIFICATION ~ ~£ ~ <2 ~: ~ § ~' ~ ~ ~ Tan. very dense, medium coarse. - SILTY SAND (SM) - - -grayish tan below 33' - - 9 SS 80 62 20.0 35 38.0 Dark gray SHALE ~o ss lDO ;o~.5' -high angle fracture at 40' 40~ - _bentonite clay seam from 40.8-41' - 25.s 113.9 16.0 _ 11 RC 92 -pyrite nodules at 42' - aB -- ~ .bentonitic clay layer from 44.8-45' 45~ 16.1 lO6.9 17.0 - -trace shell partings at 46.5' 12 RC 97 - 75 -- Bottom of test boring at 49' - 55-- SAMPLER TYPE GROUNDWATER DEPTH BORING METHOD SS - SPLIT SPOON-SPT ~ AT COMPLETION FT. HSA- HOLLOW STEM AUGER ST - PRESSED SHELBY TUBE ~ AFTER HRS. FT. CFA- CONTINUOUS FMGHT AUGERS RC - ROCK CORE ~ WATER ON RODS 23.00 FT. DC - DRIVING CASING THD - TEXAS HIGHWAY DEPARTMENT CONE 'i' AT SURVEY FT. RW - ROTARY WASH CU - CUTTINGS HPA- HAND POWER AUGER CT - CONTINUOUS TUBE ATEC Associates, Inc. V 11356Mathis '"~nue ~ RECORD OF Dallas, Texas ~ .9 (214) 556-2204 SUBSURFACE EXPLORATION Metro 263-I 681 Client City of Coppell, Texas Boring # TH-3 (Page 1 of 1) Architect Engineer Phillips - Swager Associates Job # 25-02-95-00091 Project Name PROPOSED FIRE STATION Drawn By CRF Project Location Southwestern Blvd/Coppell~ Texas Approved By, DPZ DRILLING and SAMPLING INFORMATION TEST DATA Date Started ~-Z~.-~5 Hammer Wt. 140 lbs. Date Completed 3-24-95 Hammer Drop 30 in. = o Drill Foreman RDC Spoon Sampler OD 2.0 in. I~ .-> Inspector Rock Core Dia. in. ~3 o .e ~ > Boring Method CFA She,b, Tuba OD 3.0 in. ~ >~ ~ ~ ~ ~ .'.-[, CliantlD# 0122 ContinuoueTubeOO N/A in. ~_ >>' ~ ~ ! ¥ ~= ~ ~. oc SOIL CLASSIFICATION ~ ~ ~ ~ u© =- c SURFACE ELEVATION ' ' ~ u~ u Z~ ' ' ' Dark gray, stiff, CLAY (CH) - _ I ST 80 1.5 29.0 - - _ 2 ST 100 1.7 28.0 ~s2e4~- 5~ 3 ST 100 1.8 28.0 7.0 CLAY (CL) with trace small calcareous - - deposits - 4 ST BO 3.S 25.0 - ~ 10 -hard with trace ferrous staining below - - -- _ 5 ST 901 2.1 4.5+ 100.5 28.0 - 15 - (SM) - -~ - - _ 6 SS 80 5.0 2O -medium dense, fine to medium - i - - coarse, with trace small gravel below - - - 22, _ 7 ss 100 15 20.0 - ~ 25 -medium coarse below 27" - - -- 8 SS lO0 19 16.0 -- 30 -- Bottom of test boring at 30' - Boring caved at 19' - - SAMPLER TYPE GROUNDWATER DEPTH BORING METHOD SS - SPLIT SPOON-SPT ~ AT COMPLETION 18.00 FT. HSA- HOLLOW STEM AUGER ST - PRESSED SHELBY TUBE _~ AFTER HRS. FT. CFA- CONTINUOUS FLIGHT AUGERS RC - ROCK CORE I WATER ON RODS 22.00 FT. DC - DRIVING CASING THD - TEXAS HIGHWAY DEPARTMENT CONE -I- AT SURVEY FT. RW - ROTARY WASH CU - CUTTINGS HPA- HAND POWER AUGER CT - CONTINUOUS TUBE ATEC Associates, Inc. 11356 Methia ~ue Dallas. Texaa ~ ._~9 RECORD OF (214) 556-2204 SUBSURFACE EXPLORATION Metro 263-1681 Client City of Coppell, Texas Boring # TH-4 (Page 1 of 1) Architect Engineer Phillips - Swager Associates Job # 25-02-95-00091 Project Name PROPOSED FIRE STATION Drawn ay CRF Project Location Southwestem Blvd/Coppell, Texas Approved By DPZ DRILLING and SAMPENG INFORMATION TEST DATA Idate Started ~1-~.zl.-~ll~ Hammer wt. 140 lbs. Date Completed 3-24-95 Hammer Drop... 30 Drill Foreman RDC Spoon Sampler OD 2. Inape~tor Rock Core Dia. in. ¢~ .~ [ ~, .~' ·x Boring Method CFA Shelby Tube OD 3.0 in. ,, >; ~ = S = ,., SURFACE E[~tAT~0N ' PROBABLE FIkL, reddish brown, stiff, - SANDY CLAY (CL) - I ST 60 1.4 15.0 ~3 141; _ - -D~-k-g-r~y~ ~n-e~l~'u~n-~f: ~_~ ~H) 2'0 _ -- 2 ST 80 0.8 32.0 _ -stiff below 4' 3 ST 100 1.3 - Bottom of test boring at 5' 5 32.0 - (Dry upon completion) - - 10 ~ 15~ 20 ~ 25 __ SAMPLER TYPE GROUNDWATER DEPTH BORING METHOD SS - SPMT SPOON-SPT ~Z AT COMPLETION FT. HSA- HOLLOW STEM AUGER ST - PRESSED SHELBY TUBE ~ AFTER HRS. FT. CFA- CONTINUOUS FLIGHT AUGERS RC - ROCK CORE · WATER ON RODS FT. DC - DRIVING CASING THD - TEXAS HIGHWAY DEPARTMENT CONE -t' AT SURVEY FT. RW - ROTARY WASH CU - CUTTINGS HPA- HAND POWER AUGER CT - CONTINUOUS TUBE ATEC Associate_s, Inc. V 11356 Mathi~ hUe RECORD OF Dallas, Texas , Z9 (214) 556-2204 SUBSURFACE EXPLORATION Metro 263-1681 Client Cit~ of Coppell, Texas Boring # TH-5 (Page 1 of 1) A~chitect Engineer Phillips - Swager Associates Job # 25-02-95-00091 Project Name PROPOSED FIRE STATION Drawn By CRF Project Location Southwestern Blvd/Coppell, Texas Approved By DPZ DRILLING and SAMPLING INFORMATION TEST DATA Date Started 3-24-95 Hemmer Wt. 140 lbs. Date Completed 3-24-95 Hammer Drop. 30 in. Drill Foreman RDC Spoon Sampler OD 2.0 in. In$1:~tor Rock Core Dia. in. Boring Method CFA Shelby Tube OD 3.0 in. ~. ~,~ -' ' .'~ "~ ~ Client 1{3 # 0122 Continuou, Tube OD N/A in. SURFACE ELEVATION' = ~m g <~ PROBABLE FILL, reddish brown, dark -, gray, medium stiff to stiff, SANDY 1.5 - i ST 80 1.0 30.0 _ Dark gray, stiff, CLAY (CH) _ 2 ST 8O ~.8 29.0 3 ST 10(~ 1 5 2s.o 8ottom of test boring at 5' - (Dry upon completion) - 10 15 ~ 20 25 SAMPLER TYPE GROUNDWATER DEPTH BORING METHOD SS - SPUT SPOON-SPT ~ AT COMPLETION FT. HSA- HOLLOW STEM AUGER ST - PRESSED SHELBY TUBE ~ AFTER HRS. FT. CFA- CONTINUOUS FLIGHT AUGERS RC - ROCK CORE ~ WATER ON RODS FT. DC - DRIVING CASING THD - TEXAS HIGHWAY DEPARTMENT CONE '1' AT SURVEY FT. RW - ROTARY WASH CU - CUTTINGS HPA- HAND POWER AUGER CT - CONTINUOUS TUBE TEG KEY TO SOIL SYMBOLS ~dVD CLASSnrlCATION The abbr~viatioas commonly e~loy~ on ~ch "R~o~ of Sub~fface Exploration' sh~t on ~e fi~r~ ~d ~ ~e ~xt o~ ~e m~R ~ ~ foRows: L SO~ DESC~ON V. SOIL PROPER~ SYMBO~ (A) Coh~io~ Soils N: S~rd Penetration R~is~ce: number of blows by a ~ ~. blows/~, dropp~ 30 ~ches ~uir~ ~ drive a 2' Ve~ ~m 0 m 4 O.D. ~lit-~n ~ple one f~t. ~ 5 ~ 10 ~: Uncon~ comp~ive s~g~. ~f M~ ~ 11 ~ 30 ~: Pene~meter ~con~ co~ive D~ ~ 1 ~ ~0 s~ng~, mf Ve~ D~ ~er 50 Id: N~ml de~i~. ~f v: Apparent gro~dwater level i~ia~ly ~ completion ~) Coh~ve Soils v: Gm~dwater level ~veal houa a~r completion of ddll~g ~ ~- ~f s: Water level noted on ddll~g ~ls Ve~ SoR ~ ~ 0.~ Mc: Water Content ~i 0.~ ~ 0.50 LL: Liquid Li~t. M~um Stiff 0.50 m I.~ PL: Pl~tic Li~t. Stiff 1.~ to 2.~ 5L: 5~ge Li~t V~ Stiff 2.~ ~ 4.~ Ph Pl~ficity ~dex (LL-PL) ~ ~er 4.~ ~: Liquidi~ ~dex · : Void milo ~' ~~ Gs: S~ific g~vity of ~lid p~cl~ k: C~ci~t of ~bili~ De~ of Pl~tici~ i: Hyd~ulic g~dient Pl~fici~ ~dex q: ~te of di~harge None m Slight 0 to 4 h: Hyd~ulic h~d or potential Slight 5 m I0 M~um I1 ~ 30 ~. D~G ~D 5~PL~G SYMBO~ ~gh m Ve~ ~gh ~er 30 AU: Auger Sample ~- ~~ PROPOR~ONS ~: ~ide Bit DB: Di~ond ~it ~ pe~ent 55: Split-S~l 1 1/8' I.D. md 2' O.D. T~e I ~ 10 except where not~ ~le 11 to 20 ~: Shelby Tube = 3' O.D. except whe~ Some 21 to 3~ ~d 36 to 50 WS: W~h~ Sample ~- P~CLE SI~ ~E~ICATION NOTE: ALL SOILS ~ CLASSED Boulde~ - 8 ~ch diameter or more ACCORDING TO THE UNIF~D SOI~ ~bbl~ - 3 ~ 8 ~ch dieter C~SSIFICATION SYSTEM G~vel: - Co~ - 3/4 ~ 3 ~ch - F~e - ~.0 mm to 3/4 ~ch S~d: -Co~ -2.0~to5.0~ - M~ium - 0.4 ~ to 2.0 ~ - F~e - 0.07 ~ to 0.4 ~ Silt: - 0.~2 ~ to 0.07 ~ Clay: - up to 0.~2 ~ GUIDELINE SPECIFICATIONS FOR LIME SLURRY AND WATER PRESSURE INJECTION Minimum of Two Lime and Two Water Injections A. Scope of Work The purpose of this work is to obtain a relatively uniform, moist, stable zone of soil beneath the structure. Due to the wide variation in qualifications of injection subcontractors, pressure injection is not recommended as a stabilization technique unless a full-time inspector, under the supervision of a professional geotechnical engineer, is retained. The contractor shall furnish all labor, equipment and materials to perform pressure injection of water and lime slurry beneath the structure as described below. B. Site Preparation Prior to the start of injection stabilization, the building pad should be brought to grade (prior to installing select fill where recommended) and staked out to accurately mark the areas to be injected. The injection process should be extended five feet outside the building foundation limits. Allowance should be made for 1 to 3 inches of swelling that may occur as a result of the injection process depending on soil properties and in-situ moisture. C. Materials 1. The lime slurry shall consist of clean fresh water, hydrated lime and suffactant and shall be agitated as necessary to ensure uniformity of mixture. 2. Lime may be delivered to the job site as hydrated lime (calcium hydroxide) and mixed into a slurry or as calcium oxide and slaked on the job site to produce hydrated lime slurry. In either instance, the lime shall conform to the applicable parts of ASTM #C977. 3. A non-ionic 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 water. D. Equipment 1. The injection vehicle shall be capable of forcing injection pipes into the soil with minimum lateral movement to prevent excessive blowbacks and loss of slurry around the injection pipes. The vehicle may be a rubber tire or track machine suitable for the purpose intended. 2. Slurry pumps shall be capable of pumping at least 3,000 GPH at 50-200 psi. 3. Slurry tanks shall have a suitable mechanical agitation system to insure proper mixing a uniformity of slurry. E. Application - Phase I - Lime Slurry Injection (Two Passes) 1. The injection stabilization work shall be accomplished after the site has been brought to grade and prior to installation of any plumbing, utilities, ditches or foundations. 2. Adjust injection pressures within the range of 50-200 psi at the pump. 3. Mix slurry at the rate of 2 1/2 - 3 lbs. lime per gallon of water which will produce a specific gravity of approximately 1.15 to 1.18 at 68° F (20° C). If quicklime is slaked, the specific gravity of the elevated temperature slurry must be adjusted to compensate for the decrease in density of water at slurry temperatures of 175° - 195° F using an appropriate conversion table. The injection contractor shall provide a hydrometer, Baroid Scale or other suitable method to accurately confirm slurry mixes. 4. Space injections not to exceed five feet on center each way, and inject a minimum area of five feet outside the building or foundation limits. 5. Inject lime slurry to a depth of seven feet, or to impenetrable material, whichever comes first. 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 five tons. Injections are to be made in 12" to 18" intervals down to the total depth. The lower portion of the injection pipes shall contain a hole pattern that will uniformly disperse the slurry in a 360 degree radial pattern. Inject at each interval to "refusal" (i.e., until the maximum quantity of slurry has been injected into the soil and slurry is running freely at the surface, from areas where the surface soils have fractured), or until a maximum of seven (7) pounds of hydrated lime per square foot of treated area has been installed (for two passes), whichever comes first. The quantity of lime injected shall be closely monitored on a dally basis by the lime slurry contractor foreman and the geotechnical inspector in an effort to achieve a uniform distribution throughout the treated area. The total tons of lime to be injected shall be determined as follows: The total tons of lime injected shall be confirmed from certified delivery tickets or from quicklime Slaking Batch Reports which calculate the weight of hydrate produced based on weight and purity of the quicklime slaked. If the total tons injected is less than the specified amount, the injection contractor shall, at no additional expense to the customer, re-inject the deficient amount of lime uniformly over the entire treated area or around the perimeter of the treated area, starting on the uphill side when applicable, as determined by the engineer or owner, or the customer will be refunded the price of the deficient amount of lime at the quoted price per ton. 6. The injection holes for the second pass of lime shall be orthogonally offset 2.5 feet from the previous injection pass. F. Application - Phase H - First and Second Water Injection Pass (Orthogonally OffseO 1. Following completion of the lime injection work specified in Phase I, the entire building area and 5 feet outside the building limits shall be injected with water and surfactant in the same manner and to the same total depth as specified for the lime injection. 2. Injections shall be made in approximately 12" - 18" intervals from the surface down to the specified depth, injecting to refusal at each interval. (NOTE: While conditions will vary from one site to another, as a general rule approximately I/3 gallon of water per cubic foot can be injected on a single pass.) The total number of water injection passes required will be determined by the soils engineer upon completion of laboratory testing. 3. A minimum of 24 hours should be allowed between all injection passes and between the beginning of any additional testing. 4. The injection holes for the secOnd pass of water shall be orthogonally offset 2.5 feet from the previous injection pass. G. Application - Phase III - Subsequent Water Injection Passes (Optional) 1. After waiting a minimum of 24 hours, the building pad area may need to be injected additional times. The injection holes on additional passes shall be orthogonally offset 2.5 feet from the previous injection pass. H. Inspection and Testing 1. A full-time inspector working under the supervision of a professional geotechnical engineer will be retained by the Owner to check the specific gravity of the lime slurry, observe the injection operations, record quantities of materials used, coordinate testing of the injected area(s), and other duties as required. 2. After a minimum curing time of 24 hours upon completion of the second water pass, the injected area will be tested as required to determine if additional injections with water are necessary. Tests will include moisture content, free swell, and other tests, as required, on samples obtained .from soil borings drilled in representative injected areas. Test borings should be performed to depths of 10 feet at a spacing of one boring per every 10,000 square feet injected. Samples should be obtained at 1 to 2 foot intervals and tested in accordance with general practice for lime slurry treated soils. 3. The design geotechnical engineer (ATEC) must be involved from the beginning of the lime slurry injection through subsequent water injection passes and testing to determine when the soil strata has been adequately stabilized. An average of laboratory free swell tests of 1 percent or less, with no swell test exceeding 2 percent will be considered as satisfactory injection within any injected area. To be totally responsive to our clients' wants and needs with a constant sense of urgency. To perform high quality services with technically superior personnel. To perform all assignments for a reasonable fee and within budget. To communicate with our clients frequently so there will be no surprises. To complete our assignments and deliver reports when promised. To review reports with our clients to be sure there are no misunderstandings. To deliver accurate invoices to our clients within seven (7) days after the completion of the assignment or as required by the clients. To follow up with the clients to be sure services completely satisfied their wants and needs. ATE¢ Associates, Inc. Corporate Headquarters 866§ Bash Street Indianapolis, IN 46256-1:202 (317) $77-1761 At ATEC, "Client satisfaction with a constant sense of urgency" is our goal. If you have concerns with an ATEC project or service that your local ATEC Representative has not resolved, please call 1-800-800-ATEC, a "hot line" to my office. We will do everything possible to satisfy your concerns. If you have received quality service, we would appreciate knowing that as well. Thank you for allowing us to work on your team. Sincerely, Gerald D. Mann President ATEC Associates, Inc.