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Sonic Addition-SY 940506 GEOTECHNICAL INVESTIGATION SONIC RESTAURANT COPPELL, TEXAS thru WAINSCOT7 & ASSOCIATES, INC. Dallas, Texas General In accordance with your authorization of our Proposal dated 25 April 1994, we have completed a Geotechnical Investigation for the captioned project. The site is located on the west side of Denton Tap Road and noah of Sandy Lake Road. in Coppell, Texas. The proposed facilities will consist of a new single story, brick veneer structure and su~ace parking. Purpose and Scop__e_ The purpose of this investigation was to develop specific geotechnica! data at the site of the proposed new restaurant by means of subsurface exploration and laboratory testing. This the results of the basic field and laboratory data and report presents provides recommendations pertinent to the design and construction of foundation elements for the proposed structures and pavement for the parking lots and driveways. Recommendations to facilitate design and construction were made based on the ,-,~ .... bo, ,~ and para~,-neters obtained from the investigation. The qeo!ogical "~'~; ' ~'~ interpretation of these data is considered appropriate to the extent that the investigated locations are typical of condiLions present at the project site. HENLEY JOHNSTON & ASSOCIATES, INC. Field Investigation The field or subsurface investigation conducted for this study consisted of drilling and sampling two (2) borings at the approximate locations shown on Plate 1. The boring locations were approximated ill tt~e field by the drill crew using a tape measure arid measuring wneei. Boring locations should be considered accurate only to the degree implied by the method used. The borings were advanced to a depth of about 21 feet by means of a truck-mounted rotary drilling rig utilizing wet rotary techniques. Soil samples were taken near-continuously to a depth of ten (10) feet and at intervals of five (5) feet b~,.,~v that depth to the top of rock. Near continuous cores of the bedrock were taken to termination depth. Soil materials were sampled by means of a shelby tube sampler in cohesive soils in general accordance with ASTM D 1587 and a split spoon sampler in granular soils using the Standard Penetration Test Procedures of ASTM D 1586. Samples of the bedrock materials were obtained by a double tube core barrel fi~ed with an appropriate cutting bit. Soil samples and selected rock cores were encased in polyethylene plastic to prevent changes in moisture content and to preserve in situ physical properties. Samples were classified as to basic type and texture in the field, labeled as to appropriate boring number and depth, and placed in core boxes for transport to the laboratory. Laboratory _.T. es_ti_n_g Samples received in the laboratory were visually classified by an experienced engineering geologist. The in situ unconfined compressive strength of each cohesive sample was estimated with a hand-operated pocket penetrometer. These values are used to estimate the consistency of the clays, and are noted on the individual boring logs. All soil samples were classified in accordance with the Unified Soil Classification System as shown on the enclosed sheet entitled "Legend, Lithology, Soil Consistency & Relative Rock Hardness". Bedrock samples were described using standard geologic nomenclature. To aid in the soil c!assificatio~ process, a series of Atterberg Limits and HENLEY JOHNSTON & ASSOCIATES, INC. -2- Grain Size Analysis (percent passing the number 200 sieve) were conducted. In addition, moisture content tests were performed on representative samples. All of the above test data are sum~,-narized on Plate 2. Grain size analyses were pedormed on selected granular materials recovered from the borinqs. This test is performed bypassinma sample over asieve or aseries of sieves with successively smalier openings and determining the weight of material retained on each. The percentage of weight retained to total sample weight is then computed. For this investigation, the percent material passing the No. 200 sieve only was determined. The test was performed in general accordance with ASTM D 422 procedures. Percentage of fines (Fnaterial passing the No. 200 sieve) determined by the grain size analysis is tabulated on Plate 2. Atterberg Limits were determined on portions of selected samples to determine their plasticity characteristics. The Plasticity Index (PI) is representative of this characteristic and is bracketed by the Liquid Limit (LL) and the Plastic Limit (PL). The Liquid Limit is the moisture content at or above which the soil will flow as a heavy viscous fluid; the Plastic Limit is the moisture content at or above which the soil becomes plastic. These indices were determined in general accordance with ASTM D 4318 procedures; the results are tabulated on Plate 2 and are presented graphically on the Plasticity Chart on Plate 3. Strength properties of the overburden soils were estimated with a pocket penetrometer. Strength properties of the primary formation were investigated in the laboratory by a series of Unconfined Compression tests. In the Unconfined Compression test, axial load is applied to a laterally unsupported cylindrical sample until failure occurs within the sample. The test is performed fairly rapidly (failure achieved within 2 to 10 minutes) resulting in an undrained test for the samples. Peak stress values are tabulated on Plate 2. I HENLEY JOHNSTON & ASSOCIATES, INC. -3- Subsurface Conditions Based on the exploratory borings conducted for this investigation, overburden materials present in the area of the proposed new facilities are about '15 feet thick. The specific type, depth and character of material penetrated by each of the borings may be seen in detail on the "Log of Boring" illustrations. In general, the overburden soils at the site consist of a!ternating layers of sandy clay and sand, with sand predorrfinatin9 in the deeper soil sections. The primary geologic formation is identified as strata of the Eagle Fort Shale Formation of Cretaceous Age, which consist of a firm to moderately hard calcareous shale. The borings indicate that the overp, urcten soils extend to depths from 14.4 to 15.1 feet below ground surface at this site. The soils are alluvia! sandy clays, silty sands, and sands with occasional gravel. The near surface soils, typicaily less than three to four feet in thickness, contain some varying percentages of sand, silt and clay and occasional organics and are tan to reddish brown in color. Below these upper soils, are Iow plasticity clays which are stiff to hard in consistency. The soils below the clays become generally sandier with depth with some gravels occurring sporadically through the section, but with increased abundance near the soil bedrock interface. Unweathered primary materials of the Eagle Ford Shale Formation were encountered at depths ranging from 15.1 feet in Boring No. I to about 14.4 feet in Boring No. 2. The weathered portion of the Eagle Ford Shale Formation was not encountered in this investigation, but is generally characterized by a softer consistency and a tan color. The fresh share is firm to hard and in co[or. moderately gray Groundwater levels could no~ be definitively to rotary determined due the wet drill techniques utilized in the drilling processl however, the character of the soils suggest that a perched groundwater table will be present within the granular soils. We have inferred that perched groundwater should be anticipated for drilling of the foundation piers. HENLEY dOHNSTON & ASSOCIATES, INC. -4- Foundation Desig_n Criteria Based on the results of this investigation, primarily the close proximity of the unweathered shale to the ground surface, we recommend that structural loads be supported on auger excavated, cast in place concrete, straight shaft foundation piers based in the gray shale at depths of at least 2 feet into the unweathered shale or on shallow foundations based at least 2 feet below final grade. We recommend that auger excavated, cast in place concrete, straight shaft foundation piers, based at least two feet below the top of the unweathered shale, be proportioned using the following stress transfer values: End Bearing Stress Transfer, tsf = 8.1 Side Shear Stress Transfer, Compression, tsf = 2.6 Side Shear Stress Transfer, Tension, tsf = 1.3 For foundation piers proportioned in accordance with the criteria given above, settlement is expected to be on the order of small fractions of an inch. We recommend that shallow foundations based at least two feet below final grade be proportioned using an allowable net bearing pressure of 2000 psf. For shallow foundations designed in accordance with the above criteria, we estimate that total se~lernent will be about one inch or Jess. Construction Procedures Each pier and footing installation should be vertical (within acceptable tolerances), placed in proper plan location and cleaned prior to concrete placer,-nent. Reinforcing steel cages should be prefabricated in a rigid manner to allow expedient placement of both steel and concrete into the excavation. I[ is essential that drilling or excavation and the placement of both steel and concrete be completed in a continuous operation. In all cases, no portion of the stratum being counted on to provide structural support HENLEY JOHNSTON & ASSOCIATES, INC. should be exposed to atmospheric conditions for more than eight (8) hours following the completion of drilling or excavation prior to the placement of the concrete. Based upon an expected groundwater level within the overburden soils and possibly the primary formation, it is anticipated that temporary casing may be required to complete installation of shafts extendina to th,~, ~,.omm~nd_d be~.r.n.j strata. After the satisfactory installation of any temporary casing, the required shaft penetration may be excavated by machine auger within the casing in a conventional manner. If the groundwater level is above tt;e base of any temporary casing being utilized, extreme care should be maintained at al; times to insure that the head ct the plastic concrete is higher than the static groundwater level outside tbe casing. In actual practice, it is desirable that the head of the plastic concrete be appreciably above the static groundwater level prior to breaking of the seal between the temporary casing and the bearing stratum. Once the seal is broken, the temporary casing may be slowly removed in a vertical direction only (no rotation permitted) while additional concrete is elevated to the top of the casing and placed through a tremie in order to connect with the existing concrete contained within the lower portion of tl~e shaft. Because some layers within the sands and shales may be water bearing, contingency plans should also be made for underwater placement of concrete in pier excavations. In order to verify co[.'npliance with specifications and acceptability of the bearing stratum, a qualified and experienced geotechnical observer familiar with design details must be present at all times during each shaft installation. Floor Slab and Grade Beams Based the enclosed data, the areas covered by new structures will be underlain by on clay soils of Iow volume change po,enba~ and shales of higher volume change potential. ,,,~ ,q~,~,~a Index for the 1 5 feet is 8, Although the recommended ~.~.,,,.,. averaoe~ Plasticity upper . we recommend that a stiffened waf!le type slab be used at this site. Grade beams should be proportioned using the allowable net bearing pressure for shallow foundations given in a previous paragraph. HENLEY dOHNSTON & ASSOCIATES, INC. -6- scarifying and recompacting the upper slx to eight inches of soil subgrade to a dry density of 95 to i00 percent of maximum dry density determined by a Standard Proctor Compaction test (ASTM D698) at a moisture content between minus one and plus three percentage points of the Optimum Moisture Content determined by the above test. The following pavement sections are presented for your consideration: ASPHALTIC CONCRETE Light Vehicular Traffic (_P_a__r_king Lots. Drives. Etc.). 1-I/2 inch HMAC Surface Wearin9 Course 3 i/2 inch HMAC Base Course 6 inch Compacted Subgrade Fleav_y_ Vehicular Traffic (Service Drives. Trucks. Etc.) 1-i/2 inch HMAC Surface Wearing Course 5 inch FIMAC Base Course 8 inch Compacted Subgrade REINFORCED CONCRETE !_ ia b_!...v___c--_.bi_c..L.,!.~ .r_ T__r8_ffL~ .(E_a. rkLn. g__L__oLs. Drives. Etc. ~ 5 inch Reinforced Concrete Paving (Re-Steel: #3 at 18 inches on center) 6 inch Compacted Subgrade Heavy Vehicular Traffi_c~(Trucks. Service Drives. Etc.). 6 inch Reinforced Concrete Paving (Re-Steel: #-3 at 18 inohes on center) 6 inch Compacted Subgrade Good surface drainage and treatment of landscaping areas to control irrigation water are necessary to minimize moisture changes in the clay subgrade. We recommend that polyethylene plastic, or similar, be placed between the soil surface and the concrete to HENLEY JOHNSTON & ASSOCIATES, INC. provide a vapor barrier, a bond breaker, and a barrier to pumping of soil through joints and cracks in the pavement. In the event reinforced concrete paving is used, it is essential that any and all reinforcing be placed so as to insure a minimum of 1-1/2-inch cover. It is believed that one or more of the above suggested pavement sections may be entirely suitable for use on this project. Selection of the proper section should be based on anticipated traffic loads, frequency, and long term maintenance, as well as project economics. In general, asphaltic concrete sections have a lower initial cost, but require more frequent maintenance than the concrete surface. We appreciate the opportunity to work with you on this phase of the project. Please call us when we can be of further service during later stages of design or during construction. Respectfully submitted, .,.. j ,~/ . ~..~/,~..~ 2" - ~.~-: ..... : .... .':.-~'.,; t~ William D. Flanigan, R.G. ;,.-" ",,t ,. .... : ........................... ~ I'-~HN W JOHNSTON -. o:.'; ........ ~ ............. .. ~ 'P,,'-. ,9,- ,,~;/,'~,, Jolfi'n W. Johnston. P.E. ~'~.k,~.~.-,-~- Henley-Johnston & Associates, Inc. JWJ/WDF:Its HJA No. 6246 May 6, 1994 HENLEY JOHNSTON & ASSOCIATES, INC. -9- I SONIC RESTAURANT COPPELL, TEXAS SUMMARY OF LABORATORY TESTS I SUMMARY OF INDEX PROPERTIES BORING DEPTH LL Pi MC -200 UNIFIED SOIL NUMBER (ft.~ (%) (%) (% finer) CLASSIFICATION 1 0.0-1.5 9.4 1 1.5-3.0 .... 6.8 NON-PLASTIC 1 4.5-6.0 21 6 12.6 CL--ML 1 7.5-9.0 "13.4 2 1.5-3.0 22 9 6 G Ct_ 2 3.0-4.5 21 8 10.7 CL 2 6.0-7.5 .... 2.8 13.2 NON-PLASTIC 2 7.5-9.0 83.6 SUMMAP, Y OF STRfENG-I'I-t I ES,, I PEAK BORING DEPTH STRESS MATERIAL NUMBER (ft.) (psi) TYPE I 1 18.0-18.5 212.1 SHALE. calcareous, dark gray 1 19.2-20 I 218.1 SI-IA! E, calcareoris, dark gray 2 16.3-16.7 ,-_2v.~ St-I,,,[_E. calcareous, dark gray HENLEY JOHNSTON ASSOCIATES, INC. j £],~.~¢:~t:'r~o:' CO~tS~lfCriL~, PLATE 2 70 · 30 '/ n / MH or CH 10i / . /." ~ CL~-~I' /ML or OL 0 10 20 30 40 50 60 70 80 90 100 110 LIQUID LIMIT (LL) SUMMARY OF A'I-r'ERBERG LIMITS BORING SAMPLE LIQUID PLASTICITY UNIFIED SOIL NUMBER DEPTH,ft. LIMIT INDEX CLASSIFICATION 1 1.5-5.0 NON-PLASTIC 1 4.5-6.0 21 6 CL-ML 2 1.5-5.0 22 9 CL 2 5.0-4.5 21 8 CL 2 6.0-7.,5 NON -PLASTIC SONIC RESTAURANT COPPELL, TEXAS SUMMARY OF A-'FrERBERG LIMITS HENLEY-JOHNSTON &: ASSOCIATES,INC. englneering (jeo~clence conaultanta HJA NO.: 6246 J .DATE TESTED: 04/28/94 [ PLATE 5 ;7 ,i :.-dr t'.,.-.pler '¢¢"v i_o3se Less Lho,: .c 32. ~'..q ~'"!,~ '~"' ..... .,,=.. L:*,.T ~.i:_ :'~ """ "" J-/ '' ' ~ "1 ','~"~. -;: ..................................... !/' ,' J L i,,;)'=, ,. ! '-.,: .','-,,:. '.' t · ' Sr. Sigh-'.'.' S2,'O:Cne¢.J with ..q:[e, 20ri be - cfm c:e proker', b), repeated C c. 2;OPi-:-E~L-"_, TEXAS I . , ~--.,...> $,.:n-~s'-.. '.-~ D'"-,TE: [.'.- 5...." 9-'- .... · ,. . RdJr~,T ,No.: 6245 - ub~.U,,~,., BORING No.: 1 ,:~ .... GROUND '~"'~ ~'-~' ................ ' ......... ' ~- ~' "' -'13 ~i.:;'. 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