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Home My WebLink AboutPARK SOUTH PUD, 3RD REPLAT - PRELIMINARY & FINAL - 46-88G - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTREPORT OF A GEOTECHNICAL INVESTIGATION FOR PARK SOUTH P.U.D. FORT COLLINS, COLORADO MIDDEL REALTY FORT COLLINS, COLORADO PROJECT NO. 6780-86 BY EMPIRE LABORATORIFS, INC. 301 NORTH HOWFS STREET FORT COLLINS, COLORADO 80521 TAPLE OF CONTENTS Table of Contents .............................................. i Letter of Transmittal .......................................... ii Report.................. 1 AppendixA .................................................... A -1 Test Boring Location Plan .................................... A-2 Key to Borings ............................................... A-3 Log of Borings ............................................... A-4 Depth to Ground Water Contour Map .......................... A-8 Depth to Bedrock Contour Map ............................... A -9 Appendix B.................................................... B-1 Consolidation Test Data ...................................... B-2 Hveem Stabilometer Data ..................................... B-5 Summary of Test Results ..................................... B-6 Appendix C.................................................... C -1 Empire Laboratories, Inc. GEOTECHNICAL ENGINEERING & MATERIALS TESTING December 11 , 1986 Middel Realty 1407 South College Avenue Fort Collins, Colorado 80525 Attention: Mr. Marc Middel Gentlemen: P.O Box 503 • (303) 484-0359 301 No Howes • Fort Collins, Colorado 80522 We are pleased to submit our Report of a Geotechnical Investigation prepared for the proposed Park South P.U.D„ located at the southwest corner of Horsetooth Road and Manhattan Avenue in south Fort Collins, Colorado. Based upon our findings in the subsurface, we feel that the site is suitable for the proposed construction, providing the design criteria and recommendations set forth in this report are met. The accompanying report presents our findings in the subsurface and our recommendations based upon these findings. Very truly yours, E:�7 PIRE LABORATORI S, INC. Sherrod Senior Engineering Geologist Reviewed by: Chester C. Smith, P.E. President cic P.O. Box 1135 Longmont, Colorado 80502 (303) 776-3921 ��111t11::1lfltr.. C� C" 4BUE-1 0_Ir DUI` Branch Offices P.O. Box 1744 Greeley, Colorado 80632 (303) 351.0460 Member of Consulting Engineers Council P.O. Box 10076 Cheyenne. Wyoming 82003 (307) 632-9224 REPORT OF A GEOTECHNICAL INVESTIGATION SCOPE This report presents the results of a cgeotechnical evaluation prepared for the proposed residential and commercial development located south of Horsetooth Road and west of Manhattan Avenue in south Fort Collins, Colorado. The investigation included test borings and laboratory testing of samples obtained from these borings. The objectives of this study were to (1) evaluate the subsurface conditions at the site relative to the proposed construction, (2) make recommendations regarding the design of the substructures, (3) recommend certain precautions which should be taken because of adverse soil and/or ground water conditions, and (4) make recommendations regarding pavement types and thicknesses for the proposed street sections to be constructed at the site. SITE EXPLORATION The field exploration, carried out on December 1, 1986, consisted of drilling, logging, and sampling thirteen (13) test borings. The locations of the test borings are shown on the Test Boring Location Plan included in Appendix A of this report. Boring logs prepared from the field loqs are shown in Appendix A. These logs show soils encountered, location of sampling, and ground water at the time of the exploration. Field resistivity tests were performed in selected areas throughout the site exploration. The borings were advanced with a four -inch diameter, continuous - type, power -flight auger drill. During the drilling operations, a geotechnical engineer from Empire Laboratories, Inc. was present and made continuous observations of the soils encountered. SITE LOCATION AND DESCRIPTION The proposed site is located south of Horsetooth Road and west of Manhattan Avenue in south Fort Collins, Colorado. More particularly, the site is described as Park South P.U.D. , situate in the Northeast 1 /4 of Section 35, Township 7 North, Range 69 West of the Sixth P.M., Larimer County, Colorado. The site is a vacant field currently vegetated with grass and weeds. Several irrigation laterals traverse the site in are east -west direction. The property is bordered on the north by Horsetooth Road and on the east by Manhattan Avenue, both of which are paved. Piles of fill were located along Manhattan Drive south of Boulder Street. The property is relatively flat and has positive drainage to the east. LABORATORY TESTS AND EVALUATION Samples obtained from the test borings were subjected to testing in the laboratory to provide a sound basis for evaluating the physical properties of the soils encountered. Moisture contents, dry unit weights, unconfined compressive strengths, water soluble sulfates, pH, swelling potentials, and the Atterberg limits were determined. A summary of the test results is included in Appendix, B. Consolidation, swell -consolidation and Hveem stabilometer characteristics were also determined, and curves showing this data are included in Appendix B. SOIL AND GROUND WATER CONDITIONS The soil profile at the site consists of strata of materials arranged in different combinations. In order of increasing depths, they are as follows: (1) Silty Topsoil and Fill t0aterial: The majority of the site is overlain by a six (6) inch layer of silty topsoil. The topsoil has been penetrated by root growth and organic matter and should not be used as bearing soil or as a fill and/or backfill -2- material. A four and one-half (4-1/2) foot layer of fill material was encountered at the surface of Boring 1. The fill consists of a mixture of brown silty clay and red sandy silty clay. It is not known whether the fill has been uniformly or properly compacted; therefore, it should not be used as a foundation material. (2) Silty Clay: A layer of brown silty clay underlies the topsoil in Borings 2 through 13 and extends to the lower clay stratum and/or the bedrock below. The upper silty clay contains minor amounts of sand, is plastic and exhibits generally moderate bearing characteristics in its dry to damp in situ condition. When wetted, the upper clay stratum exhibits slight to moderate swell potential; and upon loading, consolidation occurs. (3) Sandy Silty Clay: A layer of red sandy silty clay underlies the fill and upper clays. The silty clay was encountered in Borings 1 through 9, 11 and 13 at depths one (1 ) to four and one-half (11-1 /2) feet below the surface and extends to the sand and gravel stratum, bedrock and/or the depths explored. The red silty clay contains varying amounts of sated and/or gravel, lenses of sand and gravel, and exhibits generally moderate bearing characteristics in its damp to moist in situ condition. When wetted, the drier clayier portion of this stratum exhibits moderate swell potential, while the more moist, sandier portions of the stratum exhibit slight swell potential. Upon loading, consolidation occurs. (4) Silty Sand and Gravel: The gravel stratum was encountered within the clay layer in Borings 3 and 4 and below the clay layers in Borings 6, 7 and 10 at depths one (1) to ten (10) feet below the surface and extends to depths seven (7) to thirteen (13) feet below the surface. The sand and gravel is poorly graded, is medium dense, and exhibits moderate bearing -3- characteristics. The sand and gravel contains varying amounts of silt and minor amounts of clay and exhibits moderate bearing characteristics. (5) Sands tone-Siltstone-Claystone Pedrock: The bedrock was encountered below the upper subsoils in Borings 5 through 13 at depths two and one-half (2-1/2) to thirteen (13) feet below the surface and extends to greater depths. The upper two and one-half (2-1 /2) to seven (7) feet of the bedrock is highly weathered. However, the underlying interbedded sandstone, siltstone and claystone is firm and exhibits very high bearing characteristics. When wetted, the weathered Siltstone-claystone portion of the bedrock exhibits slight to moderate swell potential. The firm Siltstone and claystone exhibits moderate to high swell potential. (6) Ground Water: At the time of the investigation, free ground water was encountered in all test borings at depths seven (7) to eleven and one-half (11-1/2) feet below the surface. Water levels in this area are subject to change due to seasonal variations and irrigation demands on and/or adjacent to the site. In addition, where ground water is not already encountered on top of the bedrock stratum, surface water may percolate through the upper subsoils and become trapped on the relatively impervious bedrock stratum, forming a perched ground water condition. RECOMMENDATIONS AND DISCUSSION It is our understanding that the northern portion of the site in the area of Borings 1 through 5 is to be developed for commercial use. A preliminary investigation was prepared for this portion of the site since building locations are not known and street locations and lot sizes may vary. The remainder of the site is to be developed for single-family -4- residential construction, and a complete geotechnical investigation has been prepared for this portion of the project area. Site Gradinq and Utilities Specifications pertaining to site grading are included below and in Appendix C of this report. It is recommended that all existing fill be removed from below building and paved areas and stockpiled for reuse or wasted from the site. All topsoil should be stripped from building, filled and paved areas and stockpiled for reuse in planted areas. The upper six (6) inches of the natural subgrade below building, paved and filled areas should be scarified and recompacted two percent (2%) wet of optimum moisture to at least ninety-five percent (95°) of Standard Proctor Density ASTM D 698-78. (See Appendix C.) Fill should consist of the on -site soils, existing fill devoid of debris, or imported material approved by the geotechnical engineer. Fill should be placed in uniform six (6) to eight (8) inch lifts and mechanically compacted two percent (2%) wet of optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density ASTM D 698-78. Bedrock encountered at the site may be used as fill material in selected areas. Heavy-duty construction equipment equivalent to a D-8 tractor or a backhoe having a minimum one and one-half cubic yard bucket may be needed to excavate the firm bedrock, and bedrock used as fill should be broken into pieces less than six (6) inches in diameter. Proper placement of the bedrock as fill may be difficult, and a disc or other mixing equipment may be needed to obtain uniform moisture and proper compaction. The bedrock should be used in open and planted areas. The expansive firm claystone and siltstone bedrock should not be used as backfill adjacent to proposed structures. In computing earthwork quantities, an estimated shrinkage factor of eighteen percent (18%) to twenty-three percent (2396) may be used for the on -site soils compacted to the above -recommended density. Utility trenches dug four (4) feet or more into the upper soils should be excavated on stable and safe slopes, or the excavations should be properly shored. The firm hedrock may be excavated on -5- near -vertical slopes. Excavation of the firm bedrock may require the use of heavy-duty construction equipment equivalent to a backhoe having a minimum one and one-half cubic yard bucket. Where utilities are excavated below ground water, dewatering will be needed during placement of pipe and backfilling for proper construction. All piping should be adequately bedded for proper load distribution. Backfill placed in utility trenches in open and planted areas should be compacted in uniform lifts at optimum moisture to at least ninety percent (90%) of Standard Proctor Density ASTM D 698-78 the full depth of the trench. The upper four (4) ' feet of backfill placed in utility trenches under roadways and paved areas should be compacted at or near optimum moisture to at least ninety-five percent (95°) of Standard Proctor Density ASTM D 69R-78, and the lower portion of these trenches should be compacted to at least ninety percent (90%) of Standard Proctor Density ASTM D 698-78. Addition of moisture to and/or drying of the subsoils may be needed for proper compaction. Proper placement of the bedrock as backfill may be difficult. Stripping, grubbing, subgrade preparation, and fill and backfill placement should be accomplished under continuous observation of the geotechnical engineer. Field density tests should he taken daily in the compacted subgrade, fill , and backfill under the direction of the geotechnical engineer. Resistivity tests performed in the field and pH and water soluble sulfate tests performed in the laboratory indicate that the subsoils at the site are noncorrosive, and protection of utility pipe will not, in our opinion, be required. Fni i"Am+innc A complete geotechnical investigation has been prepared for the residential portion of the site. The commercial area located in the northern portion of the site will be discussed in a preliminary manner. Residential Area In view of the loads transmitted by the proposed residential construction and the soil conditions encountered at the site, it is recommended that the structures be supported by conventional -type spread footings and/or grade beams. All footings and/or grade beams should be founded on the original, undisturbed soil or on a structural fill extended to the undisturbed soil a minimum of three (3) feet above the firm bedrock layer and a minimum of thirty (30) inches below finished grade for frost protection. The structural fill should be constructed in accordance with the recommendations discussed in the "Site Grading and Utilities" section of this report. The structural integrity of the fill as well as the identification and undisturbed nature of the soil should be verified by the geotechnical engineer prior to placement of any foundation concrete. Footings and/or grade beams founded at the above levels may be designed for maximum allowable bearing capacity of two thousand (2000) pounds per square foot (dead load plus maximum live load). To counteract swelling pressures which will develop if the subsoils become wetted, all footings and/or grade beams should be designed for a minimum dead load of seven hundred fifty (750) pounds per square foot. The predicted settlement under the above maximum loading, as determined by laboratory consolidation tests, should be less than one (1 ) inch, generally considered to be within acceptable tolerances. The bottom of all footings should be placed a minimum of three (3) feet above the expansive firm bedrock stratum. Structures founded within three (3) feet of the firm bedrock stratum should be supported by a drilled pier foundation system. Usinq this type of foundation system, the structure is supported by piers drilled into the bedrock stratum and structural grade beams spanning the piers. Piers should be straight -shaft and should he drilled within plumh tolerances of one and one-half percent (1-1 /2%) relative to the length of the pier. The piers are supported by the bedrock stratum partially through end bearing and partially through skin friction. It is recommended that all piers have minimum ten (10) foot lengths and that they be drilled a minimum of -7- three (3) feet into the firm bedrock stratum. Piers founded at the above level may be designed for a maximum allowable end bearing pressure of fifteen thousand (15,000) pounds per square foot. It is estimated that a skin friction of one thousand five hundred (1500) pounds per square foot will be developed for that portion of the pier embedded into the firm bedrock stratum. To counteract swelling pressures which will develop if the subsoils become wetted, all piers should be designed for a minimum dead load of five thousand (5000) pounds per square foot. Where this minimum dead load requirement cannot be satisfied, it is recommended that skin friction from additional embedment into the firm bedrock be used to resist uplift. To help provide the required skin friction, the sides of the pier drilled into the bedrock stratum should be roughened. All piers should be reinforced their full length to resist tensile stresses created by swelling pressures acting on the pier. It is recommended that all grade beams have a minimum four (4) inch void between the bottom of the beam and the soil below. The predicted settlement under the above maximum loading should be negligible. Drilled piers should be designed to resist all induced lateral forces. Since all bedrock is below ground water, temporary casing of the drill holes may be required. However, since the majority of the borings were dry at the time of initial drilling, temporary casing may not be required if piers are poured immediately after drilling. For ease of construction and inspection, it is suggested that all piers should have minimum ten (10) to twelve (12) inch diameters. It is strongly recommended that the geotechnical engineer be present during the drilling operations to (1) identify the firm bedrock stratum, (2) assure that proper penetration is obtained into the sound bedrock stratum, (3) ascertain that all drill holes are thoroughly roughened, cleaned and dewatered prior to placement of any foundation concrete, (4) check all drill holes to assure that they are plumb and of the proper diameter, and (5) ensure proper placement of concrete and reinforcement. -8- Commercial Area In view of the anticipated loads transmitted by light . commercial construction and the soil conditions encountered in the northern portion of the site, it is our opinion that the structures should be supported by conventional -type spread footings and/or grade beams. Footings and/or grade beams should be founded on the original, undisturbed soil or structural fill extended to the undisturbed soil a minimum of thirty (30) inches below finished grade for frost protection. In no case should footings be founded on the existing fill encountered in the northwest portion of the site. Based on preliminary test results, footings and/or grade beams founded at the above levels may be designed for a maximum allowable bearing capacity between one thousand five hundred (1500) and three thousand (3000) pounds per square foot (dead load plus maximum live load). To counteract swelling pressures which will develop if the subsoils become wetted, all footings and/or grade beams should be designed for a minimum dead load between five hundred (500) and one thousand (1000) pounds per square foot. Basements. Dewaterinci Svstems and dabs on Grade Residential Area Due to the depth of bedrock and ground water encountered in the proposed residential areas, it is our opinion that the majority of the site is suitable for basement construction. The finished basement floor slabs should be placed a minimum of three (3) feet above existing ground water and/or the weathered bedrock stratum. In the extreme southeast corner of the project area adjacent to Boring 13, ground water levels were encountered at relatively shallow depths, extensive dewatering may be required for basement construction in this area. It is suggested conventional garden -level, crawl -space or slab -on -grade construction be used in this portion of the site. All finished basement floors placed within three (3) feet of existing ground water or the bedrock stratum I� should be provided with perimeter drainage systems. A depth to ground water contour map and a depth to bedrock contour map is included in Appendix A. The drainage system should contain a four (4) inch diameter perforated pipe running the full length of the trench. The pipe should be surrounded by clean, graded gravel from three -fourths (3/4) inch to the #4 sieve in accordance with ASTM C 33-78, Size No. 67. The gravel should extend from at least three (3) inches below the bottom of the pipe to a minimum of two (2) feet above existing ground water and/or the weathered bedrock stratum above the pipe, the full width of the trench. To minimize the cost of gravel backfill, it is suggested that the excavation be limited to the area necessary for construction; however, the trench should be a minimum of twelve (12) inches wide. We recommend that the drainage pipe be placed at least one (1) foot below the finished lower level floor and have a minimum grade of one -eighth (1 /8) inch per foot. All lower level slabs surrounded by perimeter drains should be underlain by a minimum of eight (8) inches of clean, graded gravel or crushed rock devoid of fines. The top of the gravel medium should be covered with an untreated building paper to help minimize clogging of the medium with earth backfill. To minimize the potential for surface water to enter the system, it is recommended that a clay backfill be placed over the system and compacted at or near optimum moisture to at least ninety percent (9090) of Standard Proctor Density ASTh1 D 698-78. (See Appendix C.) The drainage system should empty into a sewer underdrain should one adequately sized to accept the anticipated flows exist at the site, or the water from the drain should empty into a sump provided in the lower basement area. The sump should be a minimum of eighteen (18) inches in diameter and three (3) feet deep. A minimum of one (1) foot of clean, graded gravel meeting the above specifications should be placed adjacent to the bottom and sides of the sump. Water from the sump should he disposed of by suitable means well beyond the foundation of the building. Due to the swelling pressures exerted by the materials at subgrade, it is our opinion that the only positive solution for construction of the slab where movement will not occur is a structural floor with a void -10- beneath it. However, the cost of this type of system may be prohibitive. It is our opinion that, with certain precautions and knowing that some risk is involved, a floating floor slab may be a reasonable alternative. If the owner is willing to assume the risk of future slab movement and related structural damage, the following recommendations may reduce slab movement and its adverse effects. Subgrade below slabs on grade at the upper level should be prepared in accordance with the recommendations discussed in the "Site Gradinq and Utilities" section. If the subgrade below slabs on grade is allowed to dry below the required moisture, the subgrade should be rescarified and recompacted to two percent (20) wet of optimum moisture to the required density just prior to placement of underslab gravel and concrete. Slabs on grade should be underlain by a minimum of four (4) inches of clean, graded gravel or crushed rock devoid of fine. Slabs surrounded by perimeter drains should be underlain by a minimum of eight (8) inches of clean, graded gravel or crushed rock devoid of fines. Garage slabs should be reinforced with wire mesh running through the control joints. Slabs on grade should be designed and constructed structurally independent of bearing members. To minimize and control shrinkage cracks which may develop in slabs on grade, we suggest that control joints be placed every fifteen (15) to twenty (20) feet and that the total area contained within these joints be no greater than four hundred (400) square feet. It is emphasized that if the subsoils are kept dry, movement of slabs on grade should be minimal. However, if moisture is permitted to reach the subsoils below the slabs, heaving will probably occur. Commercial Area Basement construction is feasible in the commercial area of the site, provided finished basement floor slabs are placed a minimum of three (3) feet above existing ground water. Easements placed within three (3) feet of existing ground water should be provided with perimeter drainage systems. 'Ground water was encountered at a depth of eight (8) feet - 11 - below the surface in the eastern portion of the commercial area. Free ground water was encountered at approximate depths of eleven (11) feet below the surface in the remainder of the commercial area. Subgrade below slabs on grade should be prepared in accordance with the recommendations discussed in the "Site Grading and Utilities" section of this report. In view of the expansive nature of the subsoils, slabs on grade should be designed as floating slabs. Paved Areas It is our understanding that the northern portion of the site is to be developed for commercial construction. Streets serving this area are to be classified as local commercial streets in accordance with the City of Fort Collins. All other streets within the residential part of the development are to be classified as local or residential streets. Flexible Pavement It is our opinion that flexible pavement is suitable for the proposed street construction at the site. A flexible pavement alternate should consist of asphaltic concrete underlain by crushed aggregate base course or asphaltic concrete underlain by plant mix bituminous base course. Using the City of Fort Collins "Design Criteria and Standards for Streets" dated July 1986, a serviceability index of 2.5 for local commercial streets and 2.0 for residential streets, a regional factor of 0.75, an "R" value of 7 determined from laboratory test results, a twenty (20) year design life, eighteen (18) kip equivalent daily load applications of 25 for local commercial streets and 5 for residential streets as provided by the City of Fort Collins, and weighted structural numbers of 2.80 for local commercial streets and 2.10 for residential streets, the following pavement thicknesses are recommended: -12- Local Commercial Streets Asphaltic Concrete 4" Crushed Aggregate Base Course 9" Total Pavement Thickness 13" Asphaltic Concrete 2" Plant Mix Bituminous Base Course 51" Total Pavement Thickness 71" Residential Streets Asphaltic Concrete 3" Crushed Aggregate Base Course 7" Total Pavement Thickness 10" Asphaltic Concrete 2" Plant Mix Bituminous Base Course 31" Total Pavement Thickness 5111 The crushed aggregate base course should meet City of Fort Collins Class 5 or 6 specifications. The subqrade below the proposed asphalt pavement should be prepared in accordance with the recommendations discussed in the "Site Grading and Utilities" section of this report. Upon proper preparation of the subgrade, the base course should be placed and compacted at optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density ASTM D 698-78. (See Appendix C.) It is recommended that the asphaltic concrete and/or plant mix bituminous base course be placed in two (2) to three (3) inch lifts. All plant mix bituminous base course and asphaltic concrete shall meet City of Fort Collins specifications and should be placed in accordance with these specifications. The crushed aggregate base course shall have an "R" value between 78 and 83, the plant mix bituminous base course shall have an Rt value of 90 or greater, and the asphaltic concrete shall have an Rt value of 95 or greater. The "R" value of the pavement materials used should be verified by laboratory tests. Field density tests should be -13- taken in the aggregate base course, bituminous base course, and asphaltic concrete under the direction of the geotechnical engineer. Riaid Pavement A feasible pavement alternate at the site would be rigid pavement. Using the eighteen (18) kip equivalent daily load applications described above, a modulus of subgrade reaction of one hundred (100) pounds per square inch per inch based on an "R" value of 7, a design life of twenty (20) years, and concrete designed with a modulus of rupture of six hundred (600) pounds per square inch, the following pavement thicknesses are recommended: Local Commercial Streets Nonreinforced Concrete - 51" Residential Streets Nonreinforced Concrete - 5" Subgrade below proposed streets should be prepared in accordance with the recommendations discussed in the "Site Grading and Utilities" section of this report. Concrete pavement should be placed directly on the subgrade that has been uniformly and properly prepared in accordance with the above recommendations. All concrete used in the paving shall meet ASTM specifications, and all aggregate shall conform to ASTM C-33 specifications. The concrete should be designed with a minimum modulus of rupture of six hundred (600) pounds per square inch in twenty-eight (28) days. It is recommended that laboratory mix designs be done to determine the proper proportions of aggregates, cement, and water necessary to meet these requirements. It is essential that the concrete have a low water -cement ratio, an adequate cement factor, and sufficient quantities of entrained air. Joints should be carefully designed and constructed in accordance with the City of Fort Collins "Design Criteria and Standards for Streets" to ensure good performance of the pavement. It is recommended that all concrete pavement be placed in accordance with -14- City of Fort Collins specifications. If paving is done during cold weather, acceptable cold weather procedures as outlined in the City specifications should be utilized. The concrete pavement should be properly cured and protected in accordance with the above specifications. Concrete injured by frost should be removed and replaced. It is recommended that the pavement not be opened to traffic until a flexural strength of four hundred (1100) pounds per square inch is obtained or a minimum of fourteen (14) days after the concrete has been placed. GENERAL RECOMMENDATIONS (1) Laboratory test results indicate that water soluble sulfates in the soil are negligible, and a Tyre I cement may be used in concrete exposed to subsoils. Slabs on grade subjected to de-icing chemicals should be composed of a more durable concrete with low water -cement ratios and higher air contents. (2) Finished grade should be sloped avvay from the structures on all sides to give positive drainage. Teri percent (10%) for the first ten (10) feet away from the structures is the suggested slope. (3) Backfill around the outside perimeters of the residential structures should be mechanically compacted at optimum moisture to at least ninety percent (90°) of Standard Proctor Density ASTM D 698-78. (See Appendix C.) Puddling should not be permitted as a method of compaction. (4) Backfill placed around the interior and exterior perimeters of the structures in the commercial area should be mechanically compacted in uniform lifts. Puddling should not be permitted as a method of compaction. Interior Backfill and exterior backfill below paved areas should be compacted to a minimum of ninety-five percent (950) of Standard Proctor Density ASTM D 698-78. (See Appendix C.) Exterior backfill below planted -15- areas should be compacted to a minimum of ninety percent (90%) of Standard Proctor Density ASTM D 698-78. (5) Gutters and downspouts should be designed to carry roof runoff well beyond the backfill area. (6) Underground sprinkling systems should be designed such that piping is placed a minimum of five (5) feet outside the backfill of the structures. Heads should be designed so that irrigation water is not sprayed onto the foundation walls. These recommendations should be taken into account in the landscape planning. (7) Footing, grade beam and/or pier sizes should be proportioned to equalize the unit loads applied the soil and thus minimize differential settlements. (8) It is recommended that compaction requirements specified herein be verified in the field with density tests performed under the direction of the geotechnical engineer. (9) It is recommended that a registered professional engineer design the substructures and that he take into account the findings and recommendations of this report. GENERAL COMMENTS This complete geotechnical investigation portion of this report has been prepared to aid in the evaluation of the prorerty and to assist the architect and/or engineer in the design of this project. In the event that any changes in the design of the structures or their locations are planned, the conclusions and recommendations contained in this report will not be considered valid unless said changes are reviewed and conclusions of this report modified or approved in writing by Empire Laboratories, Inc. , the geotechnical engineer of record. Every effort was made to provide comprehensive site coverage through careful locations of the test borings, while keeping the site investigation economically viable. Variations in soil and ground water conditions between test borings may be encountered during construction. In order to permit correlation between the reported subsurface conditions and the actual conditions encountered during construction and to aid in carrying out the plans and specifications as originally contemplated, it is recommended that Empire Laboratories, Inc. be retained to perform continuous construction review during the excavation and foundation phases of the work. Empire Laboratories, Inc. assumes no responsibility for compliance with the recommendations included in this report unless they have been retained to perform adeauate on -site construction review during the course of construction. It should be noted that a preliminary investigation was prepared for the commercial portion of this site. Bearing capacities recommended in this portion of the report are based on preliminary tests. Due to the variations in soil conditions and swelling pressures encountered in this portion of the site, it is recommended that additional test borings be made prior to construction. Samples obtained from the borings should be tested in the laboratory to provide a basis for evaluating subsurface conditions. -17- No Text r • - TEST BORING LOCATION PLAN 11% A-2 KEY TO BORING LOGS i'1✓ /✓ �i TOPSOIL ••��• • . . GRAVEL ® FILL •'1• SAND & GRAVEL SILT l - SILTY SAND & GRAVEL CLAYEY SILT o�p v COBBLES i� SANDY SILT moo: SAND, GRAVEL & COBBLES ® CLAY ® WEATHERED BEDROCK SILTY CLAY SILTSTONE BEDROCK Zj SANDY CLAY ® CLAYSTONE BEDROCK El SAND SANDSTONE BEDROCK i. . SILTY SAND Ed LIMESTONE CLAYEY SAND rxx zGRANITE Pxx SANDY SILTY CLAY F-1 ' SHELBY TUBE SAMPLE STANDARD PENETRATION DRIVE SAMPLER WATER TABLE 24 HOURS AFTER DRILLING C T HOLECAVED 5/12 Indicates that 5 blows of a 140 pound hammer falling 30 inches was required to penetrate 12 inches. A-3 rlr-, vP.-,o►_1 dc'. I 110 105 100 95 90 [:, LOG OF BORINGS 0o.Z wMi W AR am W ON MAP • / I. ONPArm V/ 1L TBM, westend of radius @ flora line. Elevation = 100.0' . A-n LOG OF BORINGS ELF-UAto� Lio. 4- do. s I_1o.G 110 105 100 95 m 35 80 a — .WIN WE MAP WIN -WWA- .� • =' _ P • :M IMP A-5 LOG OF BORINGS E-L, C',/A, od do. 7 l.� o .a I.jo. 9 110 105 100 W all 80 rATMr 'sAI _ y l OVA �rAWAAlip, W M WA VA s m m i .a r, - G LOG OF BORINGS F��VATIcd 0,>. I o do. I I I�o. IZ U..13 110 105 100 95 all 35 �d �r WMEW MR Imam— A- OR ia5: — '�i A-3 �I __4_ Lf2lf� w� Flo 0 -0�► LiE. \ A-9 No Text CC'"' D BORING NO.: E; DEPTH: 4. C DRY DENSITY:113.9 PCF MOISTURE: 15.6 i CLD P M171 .58 .56. .54 .52 1-1 .50 48 .46 .44 42 SWELL - CONSOLIDATION TEST PRO. 67B0 BORING NQ.:9 DEPTH: 2.0 DRY DENSITY:104.0 PCF M 0 IS T I -IRE: L 6. 2 Fi 0.1 0, 25 0. 5 1. cl 5 1 cl APPLIED PRESSURE - TSF 8 cl -i 111 4 0 lil 0.0 -4 .0 FH Z 12 A 16 . ci 0.25 0.5 1. cl 5 APPLIED PRESSURE - TSF I cl Et--IF'IF:E LFlE;,::,F:FlTC:,F!IES IN(-7. B-3 A `D .4 10 .39cl .370 C-3 H rl: .350 CLI .310 .290 .270 .250 CONSOLIDnTION TEST PRO. 6700 BORING NO.: 13 DEPTH: 7.0 DRY DENSITY:123.7 PCF MOISTURE: a 0.1 0.25 0.5 1 . cl 5 1 ci APPLIED PRESSURE - TSF 8.0 4 .13 0.0 -16 0.1 0.25 0.5 1.e 5 RPFLIED PRESSURE - TSF EMPIRE LFlBl:DFFlTCiFIES I1,IC:. B-4 RESISTANCE R-VALUE AND EXPANSION PRESSURE OF COMPACTED SOIL CLIENT: MIDDEL REALTY PROJECT: PARK SOUTH P.U.D. LOCATION OF SAMPLE: BORING 9 AT 1.0'-3.0' ic- � SHh1F'LE DATA TEST SPECIMEN 1 2 COMPACTION PRESSURE - PSI 0 40 DENSITY - PCF 103.5 110.5 MOISTURE - : 20.7 17.6 EXPANSION PRESSURE - PSI 0.00 0.00 HORIZONTAL PRESSURE @ 160 psi 152 143 SAMPLE HEIGHT - in. 2.50 2.54 EXUDATION PRESSURE - PSI 159 271 UNCORRECTED R-VALUE 2.2 6.6 CORRECTED R-VALUE 2.2 6.6 R-VALUE AT 300 PSI EXUDATION PRESSURE = 7.2 10 80 w 60 J T- 40 20 80 111.'? 15.9 0.00 140 2.48 310 7.4 7.4 _.... . .........p.......................... j............. .............0............ �..............j. ........ _ ........................... .. .. .. ...j... ..:... .. ..................... j.............. ........ _............. j............. _ ......... ........ ........ ......... _ .. .........4............. �.............j............. .............:............. ..............j........................ ........ ......... ......... ., ......... ................................... ........._.. ...... ..................... _ ........ ........ .........y.......... _ ........ .........�............. {..............:............. ........................... j..............:........... _ ........ ......... ..y.. ..:... ..1... .. � .. ...j... ........j.............b...................................................................i........... ......... _ i.. ............. .........:.............. ............. i............. ............._.............�......................... _ .. ¢.. ..:... ... j... .. 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The geotechnical engineer shall approve all earth materials prior to their use, the methods of placing, and the degree of compaction obtained. "ATFRIAI C Soils used for all compacted fill and backfill shall be approved by the geotechnical engineer prior to their use. The upper two (2) feet of compacted earth backfill placed adjacent to exterior foundation walls shall be an impervious, nonexpansive material. No material, including rock, having a maximum dimension greater than six (6) inches shall be placed in any fill. Any fill containing rock should be carefully mixed to avoid nesting and creation of voids. In no case shall frozen material be used as a fill and/or backfill material. PREPARATION OF SUBGRADE All topsoil, vegetation (including trees and brush), timber, debris, rubbish, and other unsuitable material shall be removed to a depth satisfactory to the geotechnical engineer and disposed of by suitable means before beginning preparation of the subgrade. The subgrade surface of the area to be filled shall be scarified a minimum depth of six (6) inches., moistened as necessary, and compacted in a manner specified below for the subsequent layers of fill. Fill shall not be placed on frozen or muddy ground. C-2 PLACING FILL No sod, brush, frozen or thawing material, or other unsuitable material shall be placed in the fill, and no fill shall be placed during unfavorable weather conditions. All clods shall be broken into small pieces, and distribution of material in the fill shall be such as to preclude the formation of lenses of material differing from the surrounding material. The materials shall be delivered to and spread on the fill surface in a manner which will result in a uniformly compacted fill. Each layer shall be thoroughly blade mixed during spreading to ensure uniformity of material and moisture in each layer. Prior to compacting, each layer shall have a maximum thickness of eight (8) inches, and its upper surface shall be approximately horizontal. Each successive 6" to 8" lift of fill being placed on slopes or hillsides should be benched into the existing slopes, providing good bond between the fill and existing ground. MOISTURE CONTROL While being compacted, the fill material in each layer shall as nearly as practical contain the amount of moisture required for optimum compaction or as specified, and the moisture shall be uniform throughout the fill. The contractor may be required to add necessary moisture to the fill material and to uniformly mix the water with the fill material if, in the opinion of the geotechnical engineer, it is not possible to obtain uniform moisture content by adding water on the fill surface. If, in the opinion of the geotechnical engineer, the material proposed for use in the compacted fill is too wet to permit adequate compaction, it shall be dried in an acceptable manner prior to placement and compaction. COMPACTION When an acceptable, uniform moisture content is obtained, each layer shall be compacted by a method acceptable to the geotechnical engineer and as specified in the foregoing report as determined by applicable standards. Compaction shall be performed by rolling with approved tamping rollers, C-3 pneumatic -tired rollers, three -wheel power rollers, vibratory compactors, or other approved equipment well -suited to the soil being compacted. If a sheepfoot roller is used, it shall be provided with cleaner bars attached in a manner which will prevent the accumulation of material between the tamper feet. The rollers should be designed so that effective weight can be increased. MOISTURE -DENSITY DETERMINATION Samples of representative fill materials to be placed shall be furnished by the contractor to the geotechnical engineer for determination of maximum density and optimum moisture or percent of Relative Density for these materials. Tests for this determination will be made using methods conforming to requirements of ASTM D 698, ASTM D 1557, or ASTM D 2049. Copies of the results of these tests will be furnished to the owner, the project engineer, and the contractor. These test results shall be the basis of control for all compaction effort. DENSITY TESTS The density and moisture content of each layer of compacted fill will be determined by the geotechnical engineer in accordance with ASTM D 1556, ASTM D 2167, or ASTM D 2922. Any material found not to comply with the minimum specified density shall be recompacted until the required density is obtained. Sufficient density tests shall be made and submitted to support the geotechnical engineer's recommendations. The results of density tests will also be furnished to the owner, the project engineer, and the contractor by the geotechnical engineer. C-4