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HomeMy WebLinkAboutCT 72-24; Spanish Village Unit 1; Soils Report; 1978-01-24WILLIAM S. KROOSKOS 6. ASSOCIATES w. s. KROOSK05. C1”IL ENGINEER FOUNDATION ENGlNEERlNG I\L “ENTON. ENGlNEERlNG GEOLOGIST ENGlNEERlNG GEOLOG” ‘,‘, 4320 “ANDEVER AVENUE . SAN DIEGO. CALlFORNlA 92120 . PHONE 283.6506 .January 24, 1978 Ivlr. Cd Elliott YcMillin Construction Company 30th street & "B" Avenue rlational City, California 92050 Job h-0. 78-5560 RECEIVED SUBJECT: ?cport of Soil Investiqation Lots 7, 80, 87, 92 b 107 JP,>1 2; jcJ70 Spmish 1'171 age Unit ::o. Anillo LGaj & Palenquc Street CITY OF CARLSBAD car1 slxld, California Building Department Dear Yr. Elliott: In accordance with your request wc !mve conducted an investigation of the surface and sul~surfacc soils at the subject lots of Spanish Villa:lc Vnit :jo. 1. The cnclosr:d report sumnrarizes the results of the subsurface crplorations, test results of the typical bearing soils, and the recom:c~ntlations made by our firm for the proper design of tile stmctxcs to lx> located on the subject lots. Our investigation reveals that sofie of the lots contain low cxp;insivc clayey sands and some of the lots contain wlodicrately expansive clayc:v sands to s;indy clays. It is our opinion, that if the founrlat~ions for the ]~rolmscd structures arc properly designed in accord;lnce with the rccormcndations o:ltlincd in this rf,gort, the proposed structures will he frtx Ii-or, any adverse effects frorl tllc low to modcratc cl~a\rr>:; soils. 'Phj.s opportunity to he of service is sincerely a;>preciatcd. Very truly yours, ~!Il,I,IAFI S. KROOCKOS bi ASSOCL\TES P!SK : skm REPORT OF SOIL I~WESTIGRTI@l: LOTS 7, 80, 87, 92 L 107 SPANISII VILLAGE UNIT :JO. 1 ANILLO WAY & PALIXgQIJE STREET CARLSBAD, C/ZI,IFOKI!IA SCOPE : This report presents the findings and results of our invest- igation at the site of the proposed rtsidcnces. It is our understanding that the proposrd structures arc to be constructed of conventional tvoe foundations and footinas and of standard i I type building materials, not exceeding two !<o grading is contemplated, since the pads constructed with an existing subdivision. already been installed. stories in height. have been previously Streets and curbs have With the above in mind, this soil investigation was undertaken in 'order to: 1. Classify the existing bearing soils to an approximate depth of 5 feet below the top of existing ground and determine the prescncc and cffcct of any expansive soils that could cause detrimental damage to the proposed structures and the other improvements. 2. Dcterminc the safe soil bearing value of the firm natural ground soils and the compacted fill soils (compacted to at least 90 pcrccnt of maximum dry density). 3. Determine any construction problems that may develop at the building site as a result of the soil characteristics encountered. SITE: -- The sites havt been previously graded and arc part of Spanish Village Subdivision Unit iJo. 1 (Carlsbad Tract 72-24). The recent heavy rains has created a washout in the southwest corner of Lot 12. This depression should be refilled and recompactcd prior to construction. PRCVIOIJS b7ORI:: Please reference the Final Report on Compacted Filled Ground of Spanish Village Unit :lo. 1, prepared by Ecnton Engineering, Inc., dated january 8, 1975, their Project ::o. 73-ll-12D. Please also rcfcrcncc their Report of Preliminary Soils Investigation of Spanish Village Unit Kos. 1 and 2, prcparcd by Benton Engineering, rnc., dated llay 10, 1973. Page 2 Report of Soil Investigation Lots 7, 80, 87, 92 & 107 Spansih Village llnit No. 1 Anillo Way & Palcnque Street Carlsbad, California Job Xo. 78-5569 FIELD 1NVESTIGATIO:JS: One hand dug exploratory boring was advanced in the midst of each of the subject lots. The borings were advanced by our engineering geologist on January 23, 1973. The borings wre excavated into the existing bearing soils by means of hand tools. Disturbed samples of the soils were obtained from the borings and were hrouqht to the laboratory for testing. Boring Loqs wore prepared on the basis of an inspection of the boring excavations and the results. are summarized on the enclosed Figure No. II. LABORATORY TESTS: The following tests were performed on the sampled soils in order to properly classify them and to determine their physical and mechanical characteristics. Yechanical Analysis: This test is conducted on each soil type in order to determine the percentage of grain size. The analysis is made in conformance with A.S.T.X. 422-541'. The potential expansivity of clay soils can be determined from this test, since expansivity is a function of percentage of Colloids (fines less than .OOlmm). Compaction Test: The laboratory compaction test is performed on the typical natural ground bearing soils in accordance with A.S.T.>I. Test Yethod 3 1557 (four incll diameter meld, five layers, 25 blows each layer, 10 pound hammer, 18 inch drop, using all material passinq a No. 4 sieve). This test is conducted on the soils in order to determine the optimum moisture and the maximum dry density. The maximum density represents the value to which it is possible to compact the soil in the field wit11 the proper compactive effort. Expansion Test: An expansion test was conducted on the potentially expansive soils. This test was performed in accordance with tho requirements set forth in Chapter G of the County of San Dieqo Ordinance Xo. 2925, Test for Expansive Soils. Expansive soils arc classified as follows: Swell Expansivity 0 to 3 Percent -------------- Low 3 to 6 Percent -------------- Iledium G to 12 Percent ------------- liiqh Above 12 Percent ------------ Very I:iqh Page 3 - - - - - Report of Soil Investigation Lots 7, 80, 87, 92 & 107 Spanish Village Unit Pjo. 1 Anillo Way & Panenque Street Carlsbad, California Job ?Jo. 78-5569 According to the County of San Dicgo Test Eor Expansive Soils, in general, soils that possess a swell less than three percent are considered to bc non-expansive. COFICLUSIONS A:JD RECOMMENDATIO!~S: The followiny summarizcd conclusions and recommendations are based on the analysis of all the data and information obtained from the soil investigation. This includes our visual inspection of the building sites; field investigations and laboratory tests on the typical bearing soils: and our qcncral knowledge and experience with these natural ground and compacted fill soils. 1. The soils on these sites range from low expansive, tan, clayey sands to moderately expansive, tan, clayey sands to sandy clays. 2. Since it is the intention of constructing the proposed structures and improvements on the existing low expansive to moderately expansive soils, then it is recommended that the following work LX performed. These lots dontain soils that possess low expansive characteristics with a swell varying from 2 to 4 percent as measured by the aforfmcntioned expansion test. a. The continuous foundations shall be founded a minimum depth of 12 inches into the firm, natural yround soils. These fouiions shall be reinforced with at least tk?o NO. 4 steel bars; one bar shall bc located near the top of t& foundation and the other bar shall be located near the bottom. b. The concrete floor slabs of the structures shall be founded on at least 2 inchc: tllick of non-expansive soils, such as silts and sands, decomposed yranite, crusher run base, etc., and shall bc reinforced with GxL - 10x10 steel wire nesh. c. IJon-structural concrctc slabs such as patios and sidewalks shall be founded on at lcasi 2 inchk?s thick of non-expansive soils. e&abz&l These lots contain soils that possess moderate laracteristics with a swell varying from 3 to C percent as measured by the aforcnentioncd expansion test. a. The continuous foundation shall he founded a minimum depth of uinchcs into the firm, nautral ground soils. ThfSC Gundatlons' shall be reinforced with at least two I;o. 4 steel bars; one bar shall bc located near the top of the foundation and the other bar shall be located near the bottom. Page 4 Report of Soil Investigation Lots 7, 80, 87, 92 E. 107 Spanish Village Unit No. 1 Anillo Way & Pancnnue Street Carlsbad, California Job iJo. 78-5569 b. The concrete floor slabs of the structures shall be founded on at least 4 inches thick of non-expansive soils, sucii as silts and sands, decomposed qranitc, crusher run base, etc., and shall be reinforced with GxG~- 10x10 steel wire mesh. c. Non-structural concrete slabs such as patios and sidewalks shall be founded on at least 2 inches thick of non-expansive soils. Since the above soils arc classified as having a low to moderate expansivity, then it is our recommendation that no pre-saturation be performed. Our firm would have recommended p?%?? aturation if the clavev soils were of a bcntonitc classification and llad , I swells of over 20 percent. 3. Cxistinq natural ground cut slopes and compacted fill slopes of maximum inclinations of 1.5 llorizontal to 1.0 vertical will be stable For the materials native to these sites. 4. It is our opinion, based on test results and our experience, that thesc natural ground soils and the compacted fill soils (com,pactcd to at least 90 percent of maximum dry density) possess a safe soil bcariny value of 2,000 pounds per square foot. This soil bearing value may be utilized for the design of continuous foundations and spread footings when founded a minimum depth of 12 inches into the compacted non-expansive fill'soils and compacted non-expansive natural ground soils. This soil bcariny value may be increased one-third for design loads that include wind or seismic analysis. 5. Planter areas adjacent to the structures shall be constructed to slope away f ram the foundations and floor slabs (minimum of one percent). Planter boxes adjacent to the structures shall GC constructed with drain tile in gravel directinq the subsurface waters away from the structures towards the lower level of the sites. G. Future swimming pools or other subsurface structures shall be properly desiyncd and reinforced with steel to reflect the expansive clay soils that underlie these sites. The design of these subsurface structures shall follow the rccommcndations of a structural cngincer and soils engineeer. 7. Backfill soils beliind retaining walls and in utility trenchis which support structures, patios, sidewalks, driveways, aspllalt pavcnent, etc., (other than landscaping) shall Le placed and compacted to at least 90 percent of maximum dry density. Page 5 Report of Soil Investigation Lots 7, 80, 87, 92 & 107 Spanish Villaqc Unit plo. 1 Anillo p:ay & Panenque Street Carlsbad, California Job No. 78-5569 8. The compacted fill soils L!lat will occur within five feet of the proposed fill slopes will possess poor laterial stability, even though they will be certified to a relative compaction of 90 percent of maximum dry density or better. Proposed structures and other improvements such as walls, fences, patios, sidewalks, swimming pools, driveways, asphalt pavement, etc., that are located within five feet of the face of compacted fill slope could suffer differential movement as a result of the poor lateral stability of these soils. 9. Foundations and footings of the proposed structures, walls, etc., when founded five feet and further away from the top of compacted fill slopes may be of standard design mcetihg'the requirements of the governing agency and desiqncd in conformance with the recommended soil bcarinc; value. If proposed foundations and footinys are located closer than five feet inside the top of compacted fill slope, they shall be dcepcned one foot below a 1.5 horizontal to 1.0 vertical line :)rojectcd outward and downward from a point five feet horizontal !v inside the top of compacted fill slope (Refer to Figure No.1' ) 10. Adequate measures shall be undertaken to properly finish qradc the site after the structures and the other improvements are in place, such that the drainage waters from this improved site and the adjacent properties are directed away from tile foundations, footings, floor slabs and tops of slopes, via surface swales and subsurface drains towards the lower level of the site or to the natural drainage direction for this area. Proper surface and subsurface drainaye will insure that no waters will seek the level of the bearing soils under the foundations, footings and floor slabs which could result in undermininy and differential settlement of the structures and the other ir::>rovenents. 11. All compacted fill slopes and :latursl ground cut slopes (tii‘st do not consist of dense soils or rocks) shall lx planted with an erosion resistant plant following the qcncr.31 requirements of the City of Carlsbad. - The recommendations summarised in tliis report are based on the evidence obtained from the boring excavations; laboratory test results of the encountered natural ground soils: examination of the site by our cnginccrinp geologist and soils enqinecr and experience with the soils native to t!lis site. It is the responsibility of the owner or developer to insure that the recommendations summarised in this report are carried out in the field. Page 6 Report of Soil investigation Lots 7, 80, 87, 92 & 107 Spanish Village Unit No. 1 Anillo Way & Panen,uc Street Carlsbad, California Job IJo. 76-5569 This report and all subsequent reports and addendums automatically become a part of the building specifications. If you have any questions concerning this report, please do not hesitate to call. us. Rcspcctfully submitted, \ilLLIAM s . KROOSKOS & ASSOCIATES WSK : skm (5) Addressee . fzi&lLd.Lk , i\'illiam S. Krooskos, President RCC 11318 - - - - - - ” - \ _I 1 ‘1 - I 3 L -I- 2 ;; “L, BORING SUMMARY SHEET 5: z: tis yk? 2 -0 mz Eorlng NO 1-~-- Elevotlon _ l 5! “$7 E zs?i GC ;j- Fo\” - Mcdiun dcr~sc damp tan to liyht tan fine to mcdi,lr sand with clayey sal:d lenses (SC) ..LL ,____.. .A.. ~_~ ~.A... - Borir:q IGo. 2 Medium dense tan clayey si11 3 mixed : with some sandy clay clurlps (SC-CI.) .-,--.-~- -~-.,.- ~~--- -~--~ ~.-.~ ..~ ~,. . 3 J 0 iloring No. 3 Medium dense brown clayev sa1.d (SC) __.~ ~~~~-~~~ ..~_. ~. ~--- -,-~._~~ ., -~~~--.z~ ~-~~~.~- __.. ..~~_ Medium dense damp ligl,t t;In clayey ,~ar;d.~~to~~~~fir~~c~ sand-~. (.C;C)~ ~~~~- -.,--I 3 '\t)e~,se .tar;-, cle,"" ~sand ~(SRj I ,_~ 0 Boring No. 4 T-‘--'-.. . .._. - ,,_ -\ fii:: - b!edium dense damp cl~aycy sar,J to fine sand (SC-SP) ~-~,._- t-=-T Detise damp tan cemented clean sand (SP) 0 / L..” ._..^_ / I ~1 ~~...-,.,I .._.._.. i PLO. 5 _-.. Medium de~,se light tan moist- clayey ! / ~ I 1.. ,...,_ . Met refusal on cemented sar.A- --d .~~~..lL _.iL .~. .~I,~..~ in ..~ ~. LEQEND Undisturbed Sample +- b4o’er Table DIsturbed Sample (SM ) Unlfled So11 Cl9sslflcotlon 4 Lot.5 7, 80, 87, 92 ti 107 Spanish village unit No. 1 Job NO. 78-5569 Fiaure No. II - - - - - - I40 30 20 IO 30 SO so MECHANICAL ANALYSIS ZERO AIR VOIDS CURVES jf$-zmso SPECIFIC GRAVITY LiiORATORY CO%‘ACTION T:OST 40 SOIL TYPE SOIL CLASSIFICATION IXRING TRENCH DEPTH NO. NO. I Tan Clayey Sand 2 1 33 Tar. Clayey Sand - Fine Sarld 4 1 m Tan Clayey Sand - Fine Sand 5 1 SWELL TEST DATA I 2 3 INITIAL DRY DENSITY (pcf) 106 108 108 INITIAL WATER CONTENTI%) 11 10 12 LOAD tprf) 144 144 144 PERCENT SWELL 5.2 2.7 1.6 IFILL SUIliABIUTY TESTS IJOB NO.%5564 FIGURE NO. III I j. ., I I I I I I I I I I I 11 Proposed Structure Concrete Floor Slab, / ..- _. -. - T - .\ - Reinforcement of Foundations and Floor Slabs:' - - Top of Compacted Compacted Fill Slope Maximum Inclination Engineer - - _'. . : - ._ - Compacted Fill TYPICAL SECTION ( Showing Proposed Foundation Located Within Five Feet of Top of Compacted Fil,l Slope) Job No.78-5569 Figure No. IV - - - - - - - - i - - UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION GROUP SYMBOL TYPICAL NAMES COARSE GRAINED More than half of r"ateGial is larger than a No. 200 sieve. GRAVELS CLEAN GRAVELS More than half of Coarse fraction is larger than No. 4 sieve size but smaller than 3". GRAVELS WITH FINES (Appreciable amount) SANDS CLEAN SANDS * More than half of coarse fraction is smaller than a NO. 4 sieve SANDS WITH FINES (Appreciable amount) GW GP GV GC SW SP SM SC FINE GRAINED More than half of material is smaller than a No. 200 sieve. SILTS AND CLAYS ML Liquid Limit less than 50 -- - SILTS AND CLAYS Liquid Limit greater than 50 HIGHLY ORGANIC SOILS CL OL MlI dell graded gravels, gravel and sand mixtures, little or no fines. Poorly graded gravels, gravel and sand mixtures, little or no fines. Silty gravels, poorly graded gravel-sand-silt mixtures. Clayey gravels, poorly graded gravel-sand-clay mixtures. Well graded sand, gravelly sands, little or no fines. Poorly graded sands, gravelly sands, little or no fines. Silty sands, poorly graded sand and silty mixtures. Clayey sands, poorly graded sand and clay mixtures. Inorganic silts and very fine sands, rock flour, sa::,!y silt or clayey-silt sand nixtures with slight plasticity. Inorganic clays of lot to Medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. Organi~c silts and organic silty clays of low plasticity. lnorg.-:nic silts, micaceous or di,>tomaceous fine sandy or silty soils, elastic silts. Cl! OH PT Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and other highly organic soils. WILLIAM s. KROOSKOS & ASSOCIATES Soil and Foundations Engineers