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HomeMy WebLinkAboutEVERGREEN PARK, 2ND FILING - 3RD REPLAT OF SUBDIVISION - 24-96 - SUBMITTAL DOCUMENTS - ROUND 1 - GEOTECHNICAL (SOILS) REPORTSUMMARY OF TEST RESULTS s BORING DEPTH % DRY DENSITY UNCONFINED COMPRESSIVE STRENGTH-P.S.F. WATER SOLUBLE SULFATES-% PENETRATION BLOWS/INCHES NO. FT. MOISTURE P.C.F. 18 1.5-2.5 22.7 98.8 2,660 2.5-3.5 8/12 7,.0-7.7 17.1 50/8 14.5-15.5 7.9 /12 31/12 19 2.0-3.0 16.8 99.7 7,270 .125 3.0-4.0 8/12 7.5-8.5 11.7 40/12 14.5-15.2 10.0 50/8 20 2.0-3.0 8.6 114.0 10,280 3.0-4.0 31/12 6.0-6.8 5.7 50/91 14,5-14.9, 9.8 50/4 CKADIDC I A0nDATn DICC IAIP SUMMARY OF TEST RESULTS BORING NO. DEPTH FT. % MOISTURE DRY DENSITY P.C.F. UNCONFINED COMPRESSIVE STRENGTH-P.S.F. WATER SOLUBLE SULFATES-% PENETRATION BLOWS/INCHES 12 2.0-2,8 3,4 50/91 6,0-6,7 2.9 50/8 13,5-14.3 10,2 50/9 13 2.0-3.0 17.5 109.7 1,830 3.0-4.0 4/12 6.0-7.0 4.7 40/12 i 13.5-14.5 6.4 48/12 14 2.0-3.0 +. 18.6 108.8 1,900 .150 3.0-4.0 12/12 7.0-8.0 13.9 25/12 13.5-14.4 7.7 50/10 15 1.5-2.5 27.6 96.4 4,440 .205 2.5-3.5 4/12 7.0-8.0 16.1 29/12 13.5-14.2 8.6 50/71 16 1.5-2.5 2.5-3.3 22.3 1.6 104.3 2,760 50/9 6.0-6.8 12.4 50/8 13.5-14.4 8.0 50/101 17 2.0-3.0 12.2 112.3 1,800 3.0-4.0 38/12 7.0-8.0 20.4 20/12 14.5-15.3 7.2 50/9 I ' FMDIQF I ARCIQATC1QIFi. INC SUMMARY OF TEST RESULTS BORING DEPTH % DRY DENSITY UNCONFINED COMPRESSIVE STRENGTH-P.S.F. WATER SOLUBLE SULFATES-% PENETRATION BLOWS/INCHES NO. Fr. MOISTURE P.C.F. 6 1.5-2,5 11,0 111,9 11430 17/12 2,5-3.5 2.9 50/6 6,0-6,5 1,9 32/12 13,5-14.5 8,0 7 3.6-3.5 7.2 107.3 50/7 3.5-4.1 3.5 50/3 7.0-7.3 2.1 50/81 13.5-14.2 6.7 8 2.0-2.8 . 3:8 .053 50/81 37/12 6.0-7.0 1.7 32/12 13.5-14.5 9.1 1 = 9 3.0-4.0` 20.3 104.7 1,050 47/12 4.0-5.0 1.9 50/9 7.0-7.8 3.9 50/8 13.5-14.2 7.3 10 3.0-4.0 8,4 111,7 -680 4.0-5,0 1,9 38/12 7,0-8,0 8,8 50/11 13,5-14,4 6,5 50/10 11 2.0-3.0 21.0 91.5 1,530_ .063 3.0-4.0 2.1 41/12 6.0-6.6 3.8 50/7 13.5-14.4 8.0 50/10 II r l nIOC I A0nDATr%0ICC Wr SUMMARY OF TEST RESULTS BORING NO. DEPTH FT. % MOISTURE DRY DENSITY P.C.F. UNCONFINED COMPRESSIVE STRENGTH-P.S.F. WATER SOLUBLE SULFATES-% PENETRATION j BLOWS/INCHES I 1 1,5-2.5 14.7 115.0 10,130 2,5-3,5 5.2 17/12 7.5-8.3 3,8 50/91 13.5-14.2 18.0 50/8 1 2 1.5-2.5 18.1 104.4 2,070 .063 2.5-3.5 8/12 7.0-7.5 2.8 50/51 13.5-14.2 6.6 50/8 3 1.5-2.5 19.2 107.4 5,660 2.5-3.5•' 5.1 47/12 7.0-7.5 1.9 50/61 13:5-14.5 6.5 40/12 4 1.5-2.5' 18.6 110.5 5,500 2.5-3.5 9.3 17/12 6.0-6.5 2.9 50/5 13.5-14.5 9.0 50/12 5 1.5-2.5 17.6 110.7 3,250 2'.5-3.5 4.0 26/12 7.0-7.8 2.7 50/9 13.5-14.3 12.1 50/9 FAIADIDF 1 AQn0ATPIDIFC INr I : i .57 .56 0 .55 .54 .53 CONSOLIDATION --SWELL TEST QI 0.5 1.0 APPLIED PRESSURE—TONS/SQ. FT. f/Oxavr,1 0.1 0.5 1.0 APPLIED PRESSURE-TONS/SQ. FT. FM PIDF 1AR7�AT(1DIF[ INS' BORING NO 19 DEPTH Z • U DRY DENSITY 106.4#/ft. _. % MOISTURE 16. R& 5 10 5 10 .69 .68 0 .67 0 0 .66 .65 .64 .63 J J W z 2 0 H Q J a 3 z 0 u CONSOLIDATION --SWELL TEST BORING NO. 15 DEPTH DRY DENSITY— .ra#Lft % MOISTURE 27.6% 0.1 0.5 1.0 5 10 APPLIED PRESSURE—TONS/SQ. FT. j of 0.5 I .v v APPLIED PRESSURE—TONS/SQ. FT. EMPIRE '1.A6904TORIES. INC. w Lf -CONSOLIDATION-SWELL TEST .43 A( ! lj I. �■■�11111�BORING , '�■■�IIIII�DRY MEN�1IIII=■■111111 = E: �:!111=■■111111 MEM111111MEM111111 =Emllllllmlmmllllll MEM111111MEM111111 mmollillimmoollill MEM111111MEM111111 0.1 0.5 1.0 5 10 APPLIED PRESSURE-TONS/SQ. FT. 0.1 0.5 1.0 APPLIED PRESSURE-TONS/SQ. FT. FMDIRP' l0 f iiAw wr Wf CONSOLIDATION --SWELL TEST .76 .75 .74 .73 o .72 0 o .71 :70 .69 .68 . 7 BORING NO 1 DEP DRY DENSITY_",24� % MOISTURE 21 _0% 6 0.1 0.5 1.0 5 10 APPLIED PRESSURE TONS/SQ. FT. 0.5 1.0 APPLIED PRESSURE—TONS/SQ. F,MPIRF LABORATORIES. INC a .4 r .62 o .61 c o .60 .59 . 58' CONSOLIDATION --SWELL TEST BORING NO. 2 DEPTH 1 . 5' DRY DENSITY A na _ AM3 % MOISTURE 1 R _ 1 £ 0.1 0.5 1.0 5 10 APPLIED PRESSURE—TONS/SQ. FT. 01 0.5 1.0 5 10 APPLIED PRESSURE—TONS/SQ. FT. FMPIDF 1 ag% 1DAR APIFC It f LOG OF BORINGS fLEri4t/0 0 /T o, /B o. /J o. D 4960 4955 4950 4945 4940 an0 owl fill �c : rI c itid! 4935 NOTE: Bench Mark, Top of bonne. bolt of fire hydrant at SW corner of Conifer Street & Redwood Street Elevation = 4963.38' EMPIRE LABbRATORIES, INC. LOG OF BORINGS fZ6 4T/O 4960 4955 4950 4945 4940 �I �®�= • OBI-�� - .94 ■� EMPIRE LABORATORIES, INC. C . LOG OF BORINGS E�Erario o. 9 0. o o. o 4960 4955 4950 4945 4940 4935 �, 11ZA • . . ." . 47 12 • • ' 50 9 �� o' e•O V�50/ i . . y�- OAY • p �.,� 50 8•.►••• . off 0. 50 10 A � 0 ' 50 10 .D 50/9 EMPIRE ,LABORATORIES, -INC. - I 4965 4960 4955 4950 4949 LOG OAF BORINGS 7TIM 7771 26/12 CP 17/12 -!,.1;; 50/7 •50/84 50/9 50/65 A Z,37,/12, 3 C" 0; A. ?Ao 32/12 50/84 EMPIRE- LA:Bbl4tORIES, INC. M LOG OF BORINGS 4965 4960 4955 495( Ad�. v71 8 12 ► i ��.; 47 12 % i / ►17117 0/5 .� •i,� �.e ems✓ ei.. •�•r 505 ! 50/ 8 e a • — /' 40 12 " '/ • _ e 4945 4940 EMPIRE LABORATORIES, INC. • C KEY TO BORING LOGS TOPSOIL �••; GRAVEL ® FILL SAND & GRAVEL SILT i SILTY SAND & GRAVEL CLAYEY SILT :p COBBLES •/�' /. % SANDY SILT v • �. SAND, GRAVEL &COBBLES ® CLAY ® WEATHERED BEDROCK SILTY CLAY PH SILTSTONE BEDROCK SANDY CLAY ® - CLAYSTONE BEDROCKLid QSAND r1 SANDSTONE BEDROCK / /• SILTY SANG LIMESTONE CLAYEY SAND GRANITE • ' SHELBY TUBE SAMPLE STANDARD PENETRATION DRIVE SAMPLER WATER TABLE 41 HOURS AFTER DRILLING C HOLECAVED 5/12 Indicates that 5 blows of a 140 pound hammer falling 30 inches was required to penetrate 12 inches. —12— TEST BORING LOCATION PLAN Caftal Tao e/ 6endt/6e/1 i/ 1/[ A ✓.drf>f 15 / ,. a of Conifer jrl e Ao1wi F_M.010F 1 Apo-dAToRIFS, INC. `GENERAL COMMENTS The analysls and recommendations submitted In this report are based upon the data obtained from the soil borings performed at the locations indicated on the Test Boring Location Plan. This report does not reflect any variations which may occur between these borings. The nature and extent of variations between the borings may not become evident until construction. If variations are evident, It will be necessary for a re-evaluation of the recommendations of this report to be made after performing on -site observations during the construction period and noting the characterlstics of any variations. 9 o � ■ (2) Finished grade should be sloped away from the structures on all sides to give positive drainage. It is suggested that ten percent (10%)'for the first ten (10) feet away from the structures be provided. (3) Backflli around the outside perimeter of the structures should be mechanically compacted at optimum moisture to at least ninety percent (90%) of Standard Proctor Density. Puddling should not be permitted as a method of compaction. (See Appendix A.) (4) All plumbing and utility trenches underlying slabs and paved areas should be backfliled with an approved material compacted to at least ninety-five percent (95%) of Standard Proctor Density. Puddling should not be permitted as a method of compaction. (See Appendix A.) ; (5) Gutters and downspouts should be provided on the structures In such a manner that water from the roof area Is discharged well beyond the backflli area. (6) An attempt should be made to proportion footing sizes in such a manner that the unit loads applied to the soil are nearly equal In order that dlfferentlal-settlements will be minimized. i (7) It is recommended that all compaction requirements specified herein be verified In the field with density tests performed under the supervision of an experienced soils engineer. (6) It Is recommended that a. registered professional engineer design the substructures and that he take Into account the findings and recommendations of this report. f n 0 All topsoil, organic matter and other unsuitable materials should be stripped and removed from the street subgrade prior to placing any fill material, subbase, or base course. The finished subgrade should be a minimum of three (3) feet above existing groundwater elevations. All subbase, base course, and asphaltic concrete shall meet City of Fort Collins specifications and should be placed in accordance with these specifications. Retention Pond It is our understanding that a retention pond Is proposed In the area of Boring 2. The material encountered within the proposed excavation consists of silty clays, and sands and gravels. The clay and gravel can be excavated by conventional equipment; however, dewatering will be required or a drag line will have to be used to excavate below existing groundwater. If a berm Is provided around the pond, It should be constructed with the upper silty clays removed from the -pond area. The berm should be com- posed of the silty clay compacted at optimum moisture to at least ninety-five percent (95%) of Standard Proctor Density. The berm should be constructed on slopes no steeper than 3:1. The silty clay and pit run gravel materials are suitable for use as fill under building and paved areas. However, It Is recommended that the plastic clays not be placed within the upper one (1) foot, and preferably the upper eighteen (18) Inches, of the finished subgrade below slabs on grade. This material should be compacted slightly wet of optimum moisture to at least ninety percent (90%) of Standard Proctor Density. The gravel material excavated from the pond area Is suitable for fill In paved areas, as well as under slabs on grade. I . GENERAL RECOMMENDATIONS (1) * Laboratory test results Indicate that water soluble sulfates In the soil are positive, and a Type 11 cement should be.used In all ,concrete exposed to the soil. -a_ 6 • a All remaining streets between Redwood Street and Lodgepole Drive, including these streets, should be designed for the thicknesses listed below. Residential Streets Select Subbase S° Select Gravel Base Course 4• Asphaltic Concrete _29 _ Total Pavement Thickness 11" Collector Streets Select Subbase 68 Select Gravel Base Course 68 Asphaltic Concrete 2" Total Pavement Thickness 140 Arterial Streets Select Subbase 100 Select Gravel Base Course 6• Asphaltic Concreto 2' Total Pavement Thickness low In areas where streets are cut such that the gravel below forms tho subgrade then the following minimum pavement thicknesse's may be used. Residential Streets Select Gravel Base Course 2" Asphaltic Concrete 48 Total Pavement Thickness 6" Collector S Arterial -Streets Select Gravel Base Course 65 Asphaltic Concrete 2• Total Pavement Thickness 8" M The upper clay soils encountered at the site are plastic and may be susceptible to additional swelling if they are allowed to be dried out below their In -situ moisture contents and then rewetted. Therefore, It Is recommended that all foundation and building excavations not be allowed to remain open for long periods of time to allow drying of the clay soils below their In -place moisture contents. Streets Soils are classified and group Indexes were determined at various locations within the proposed subdivision for the purpose of developing criteria for the pavement design. Group Indexes of the upper soils at the site range from 1.4 to 19.0 . Due to variations In the soil conditions at the site, several pavement designs wl I I be developed fm the sU4dlvlslort the northern portion of the site Including Coulter Circle, Foxtall Street, Brewer Circle, Sugarpine Street, Sitka Street, Monterey Circle, and Redwood Street east of Lodgepole Drive should be designed for the following thicknesses using the above criteria: Residential Streets Select Gravel Base Course S" Asphaltic Concrete 2" Total Pavement Thickness 7" r Collector Streets Select Gravel Base Course 8" Asphaltic Concrete 2" Total Pavement Thickness 10" - Arterial Streets Select Subbase s" Select Gravel Base Course 6" Asphaltic Concrete 2" Total Pavement Thickness 13" LM north of Redwood Street, providing the finished basement floor slabs are placed a minimum of three (3) feet above existing groundwater elevations. Garden level construction Is feasible In the central portion of the proposed development between Redwood and Brlstlecone Streets, west of Lodgepole Drive. The finished lower garden level floors should be placed a minimum of three (3) feet above existing groundwater. Due to the relatively shallow depth to groundwater encountered In the southern portion of the site, it Is our opinion that basement and/or garden level construction Is not feasible In this area. It Is recommended that conventional crawl space or slab -on - grade construction be utilized In the area south of Brlstlecone Street. The bottom crawl space elevation and all slabs on grade In this area should be placed a minimum of three (3) feet above existing groundwater. Slabs on Grade The existing soils encountered near the surface at the site are adequate for supporting normal floor loads. The upper six (6) Inches of topsoll should be removed from within the limits of the structure. Fill material supporting slabs on grade should be an approved material compacted slightly wet of optimum moisture to at least ninety percent (90%) of Standard Proctor Density: (See Appendix A.) All slabs on grade founded on the upper clays and slits should be underlain by a minimum of four (4) Inches of gravel or crushed rock devoid of fines. The gravel layer will act as a capillary break and will help to distribute floor loads. Slab's on grade founded on the gravel stratum should be underlain by a two (2) Inch leveling course composed of gravel or crushed rock devoid of fines. It is further recommended that the clay subgrade below slabs on grade be slightly wetted down prior to placement of any concrete and that slabs on grade in these areas be designed structurally Independent of all bearing members. To minimize and control shrinkage cracks which will develop in slabs on grade, It Is suggested that control Joints be placed every fifteen (15) to twenty (20) feet and that the total area contained within these Joints be not greater than four hundred (400) square feet. r (7) Groundwater: At the time of the Investigation, free groundwater was encountered at depths of one and one-half (11) to eleven and one-half (111) feet below the surface. Water levels In this area are subject to change due to seasonal variations and irrigation . demands on and adjacent to the site. Test Borings 1, 12, 18, and 20 were cased so that groundwater levels could be monitored throughout the Irrigation season. RECOMMENDATIONS AND DISCUSSION Foundation It Is our understanding that conventional single-family residential struc- tures are proposed for the site. In view of the loads transmitted by these types of structures and the soil conditions encountered at the site, It is recommended that the structures be supported by conventional -type spread footings and/or continuous grade beams. All footings and/or continuous grade beams should be founded on the original undisturbed soil a minimum of thirty (30) Inches below finished grade for frost protection. The identification and undisturbed nature of the soil should be verified by an experienced soils engineer prior to placement of any foundation concrete. Footings and/or grade beams founded at the above level may be designed for a maximum allowable bearing capacity of two thousand pounds (2000#) per square foot (dead load plus maximum live load) . To counteract swelling pressures which will develop If the clay subsoils become wetted, all footings and/or grade beams founded on the silty clay and/or. sandy silty clay stratum should be designed for a minimum dead load of five hundred pounds (500#) per square foot. The predicted settlement under the above maximum loading as determined by laboratory consolidatlon.tests should be less than 0.50 Inch, generally considered to be within acceptable tolerances. Basements In our opinion basement construction is feasible only In the northern portion of the subdivision. Basement construction Is feasible in the area r so 7. s ; (3) Sandy Silty Clay: This stratum was encountered below the topsoil and/or upper silty clay layer In Borings 1 through 7 and.exterids to the gravel stratum below. The red to tan silty clay layer contains varying amounts of sand, Is moderately plastic, and exhibits moderate bearing characteristics In Its generally molst In -situ condition. When wetted, the shearing strength of the sandy silty clay stratum Is reduced, and upon loading, consolidation occurs. (4) Sandy Silt: This stratum was encountered In Borings 9, 10, and 13 at depths of one (1) to three (3) feet below the surface and extends to the gravel below. The sandy slits are non -plastic, and exhibit moderate bearing characteristics. When wetted, and upon loading, the silts consolidate readily. (5) Sand, Gravel and Cobbles: The gravel stratum was encountered at depths of one (1) to seven (7) feet below the surface and extends to depths of thirteen (13) to greater than fourteen and one-half (14}) feet below the surface. The gravel stratum Is poorly graded and exhibits moderate to high bearing characteristics In Its medium dense to dense natural state. It Is estimated that the cobbles within the gravel stratum vary In size up to twelve (12) Inches In diameter. (6) Siltstone (Bedrock): The bedrock was encountered In Boring 1 Iat a depth of thirteen (13) feet below the sur- face and extends to greater depths. The upper one-half (}) foot of the bedrock Is highly weathered; however, the underlying siltstone Is firm and exhibits very high bearing characteristics; -f = i. The site consists of Irrigated farm fields planted In grain and corn. A concrete lined Irrigation ditch forms the north property Tine and the Lake Canal forms the south prokrty line. Many small Irrigation laterals transverse the property. The area is relatively flat and has minor drainage to the south and east. LABORATORY TESTS AND EXAMINATION Samples obtained from the test borings were subjected to testing and - Inspection In the laboratory to provide a sound basis for determining the physical properties of the soils encountered. Moisture contents, dry unit weights, unconfined compressive strengths, water soluble sulfates,. swelling potentials, and the Atterberg Limits were determined. A summary of the test results Is included on pages 23 through 27 . Consolidation and swell - consolidation characteristics were also determined, and curves showing this data are Included on pages 18 through 22 . . SOIL AND GROUNDWATER 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: The site Is overlain by a one (1) foot layer of silty topsoil. The upper six (6) inches of the topsoil have been penetrated by plant roots and organic matter and should not be used as a bearing soil or as a backfill material. (2) Silty Clay: This stratum underlies the topsoil In the south portion of the property In Borings 9, 10, 11; 14 through 20, and extends to depths of two (2) to seven (7) feet below the surface. The silty clays are highly plastic and exhibit moderate bearing characteristics In their damp to moist natural state. When wetted, the drier portion of the clay stratum exhibits slight swelling potentials and precautions should be taken to prevent wetting of the silty clay layer. u REPORT OF A SOILS AND FOUNDATION INVESTIGATION This report presents the results of a Soils and Foundation Investigation prepared for the proposed subdivision located east of Conifer Street In northeast Fort Collins, Colorado. The Investigation was carried out by means of test borings and laboratory testing of samples obtained from these borings. The objectives of this Investigation were to: (1) determine the suitability of the site for construction purposes, (2) make recommendations regarding the design of the substructures, and (3) recommend certain precautions which should be taken because of adverse soil and/or groundwater conditions. SITE INVESTIGATION The field Investigation, carried out on May 17, 19 and June 2, 1976, consisted of drilling, logging, and sampling twenty (20) test borings. The locations of the test borings are shown on the Test Boring Location Plan Included on page 11 of this report. Boring logs prepared from the field logs are shown on pages 13 through 17 . These logs show soils encountered, location of sampling, and groundwater at the time of the Investigation. All borings were advanced with a four -Inch diameter, continuous - type, power -flight auger drill. During the drilling operations, afield engineer from Empire Laboratories, Inc., was present and made a continuous visual Inspection of the soils encountered. SITE LOCATION AND DESCRIPTION The proposed site is located betewen Conffer Street and Llndenmeler Road on the west and oast and the Lake Canal on the south In Fort Collins, Colorado. More particularly, the site Is described as the East 1/2 of Section 1, Township 7 North, Range 69 West of the Sixth P.M., Larimer County, Colorado. -1- M Empire LaMoratories, Inc. P.O. Box 429 e 214 North Howes Fort Collins. Colorado 80522 e Telephone (303) 484.0359 June 8, 1976 Northeast Engineering 817 East Douglas Road Fort Collins, CO 80521 Attention. Mr. F. L. Jackson Gentlemen: We are pleased to submit our Report of a Solis and Foundation Investigation prepared for the proposed subdivision'located in northeast Fort Collins, Colorado, as requested. Based upon our findings In the subsurface, we feel that the site is suitable for the proposed construction, providing the design criteria and recommenda- tions as 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, EMPIRE LABORATORIES, INC. ' i���! Nell R. Sherrod Engineering Geologist nmp Reviewed by: Chester C. Smith, P.E. Executive Vice President 2575 "' AIPG �f4 R S:IE�`�di �r ri161 UQ0 :D 9-at�s��) N 480fe RM MATERIALS AND FOUNDATION ENGINEERS e MEMBER OF CONSULTING ENGINEERS COUNCIL OFFICES AND LABORATORIES IN FORT COLLINS, COLORADO AND CHEYENNE. WYOMING TABLE OF CONTENTS Table of Contents ....................................... Letter of Transmittal .................................... Report .................................................. Test Boring Location Plan ............................... Key to Borings ................................. 0........ Log of Borings .......................................... Consolidation Test Data ................................. Summary of Test Results ................................ Appendix A ............................................. i I I 1-10 11 12- 13-17 18-22 23-27 28-29 REPORT OF A SOILS AND FOUNDATION INVESTIGATION FOR NORTHEAST ENGINEERING FORT COLLINS, COLORADO PROJECT NO. 2323-76 _ RE: EVERGREEN PARK, 2ND FILING FORT COLLINS, COLORADO BY EMPIRE LABORATORIES, INC. 214 NORTH HOWES STREET FORT COLLINS, COLORADO 80521 w