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HomeMy WebLinkAboutCT 73-50; JEFFERSON STREET; SOISL REPORT; 1974-06-12, SOIL AND ::MATERIAL TESTING LABORATORY OF' NORTH COUNTY, INC. 12 June 1974 423 HALE AVE. -ESCONOIDO, OAL!"F'."~2025 Mr. John McKeand 2525 Jefferson Ave., Apt. K Carlsbad, California 92008 ESCONDIOO -"746-2333 Re: Job No. 74-68 Subject: Grading Recommendations Dear Mr. McKeand: Proposed Apartment Complex Escondido Tract 73-50 2535 Jefferson Avenue Carlsbad, California . Enclosed are our grading recommendations_and observations on soil conditions as you requested for your above referenced project legally describ-ed as a Portion of Sec.l, T12S, R5Ll, S.B.B.&: M., City of Carlsbad, state of California. It is understood the site is intended to be developed fbr three two and three story wood frame apartment buildings. There will also be a one story building towards the front of the site. The building foundations will consist of concrete slab-on-grade with continuous concrete wall footings. The maximum cuts and fills will be in the order of 9 and 2 feet respectively. On 11 June 1974 I inspected the site and reviewsd the Grading ,Plan by E. Brian Smith, Eng., Carlsbad. The subject tract is a parcel B8 feet fronting Jefferson Street, and extending 495 f~et towards the lagoon in the west. The site is gently sloping wester~y and' contains an existing house, shed, and some treftE CETVE D central porfion. These features are ·to be removed during grading. , J;l;lN 1 8 1974. CITY OF CARLSBAD Englnee.ring Department This laboratory did the fill control and foundation recemmen- d~tions for the apartment directly to the south (Appleby -Job No. 71-41) and the apartments directly to the north (McKeand-Job No. 72-87). Experience gained from these jobs and inspection of the • site indicate no adverse soil conditions are to be expected on the subject site. There are no obvious slides or known slides in the araa. Inspection of the footing trenches for the westerly most bui~ding on the McKeand job revealed the footings were founded in a weakly cemented sandstone: These same conditions are anticipated for the westerly most building on the ~ubje8t project. The grading ( plan however indicates this building will be located fUrther away from the bluff and hence in a more stable position. The root system of large trees and any large buried objects encountered during grading should be removed and the voids back- filled with compacted soil. Any clay found within two feet of final grade should be uhder- cut and replaced with compacted ron expansive soil which is !sun- d.ant on site. Enclosed is a copy of our general grading specifications. Please notify us at least several days before grading starts to discuss the grading operation and testing reqUired. Respectfully submitted, SOIL AND MATERIAL TESTING LABORATORY OF NORTH COUNTY, INC. Claude B. Parker Registered Civil Engineer #18,987 Certified Engineering Geologist #922 Distribution: 44 Addressee mb SOIL AND MATERIAL TESTING LABORATORY CF' NCRTH CCUNTY. INC. 2 J SOIL AND MATERIAL TES'l'ING LABORATORY OF NORTH COUNTY, INC. 423 HALE AVE. -ESCONDIDO, CALIF. 92025 ESCONDIDO -746-2333 SPECIFICATIONS FOR CONSTRUCTION OF CONTROLLED FILLS GENERAL DESCRIPTION: The construction of controlled fills shall consist of adequate preliminary soil inv~stigations, and clearing, removal of existing structures and foundations, preparation of land to be filled, excavation of earth and rock from cut area, compaction and control of the fill, and all other work necessary to complete the grading of the filled areas to conform with the lines, grades, and slopes as shown on the' accepted plans. CLEARING AND PREPARATION OF AREAS TO BE FILLED: (a) All fill control projects shall have a preliminary soil investigation or a visual examination, depending upon the nature of the job, by a qual- ified soil engineer prior to grading. (b) All timber, trees, brush, vegetation, and other rubbish shall be re- moved, piled and burned, or otherwise disposed of to leave the prepared areas with a finished appearance free from unsightly debris. (c) Any soft, swampy or otherwise unsuitable areas, shall be corrected by drainage or removal of compressible material, or both, to the depths in- dicated on the plans or as directed by the soil engineer. (d) The natural ground which is determined to be satisfactory for the support of the filled ground shall then be plowed or scarified to.a depth of at least six inches (6") or deeper as specified by the soil engineer, and until the surface is free from ruts, hummocks, or other uneven fea- tures which would tend to prevent uniform compaction by the equipment to be used. (e) No fill shall be placed until the prepared native' ground has been approved by the soil engineer. (f) Where fills are made on hillsides with slopes greater than 5 (hori- zontal) to 1 (vertical), horizontal benches shall be cut into firm un- disturbed natural ground to provide lateral and vertical stability. The initial bench at the toe of the fill shall be at least 10 feet in width on firm undisturbed natural ground at the elevation of the toe stake. The soil engineer shall determine the width and frequency of all suc- ceeding benches which will vary with the soil conditions and the steep- ness of slope. (g) After the natural ground has been prepared, it shall be brought to the proper moisture content and compacted to not less than 90% of max- imum density, A.S.T.M. D1557-64T. <l. '. (h) Expansive soils may require special compaction specifications as directed in the preliminary soil investigation by the soil engineer. (i) The cut portions of building pads in which rock-like material exists may require excavation and recompaction for density compatibility with the fill as directed by the soil engineer. MATERIALS: The fill soils shall consist of select materials graded so that at least 40 percent of the material passes the No. 4 sieve. The material may be obtained from the excavation, a borrow pit, or by mixing soils from one or more sources. The material used shall be free from vegetable matter, and other deleterious substances, and shall not contain rocks or lumps greater than 6 inches in diameter. If excessive vegetation, rocks, or soils with unacceptable physical characteristics are encountered, these materials shall be disposed of in waste areas designated on the plans or as directed by the soil engineer. If soils are encountered during the grading operation which were not reported in the preliminary soil invest- igation, further testing will be required to ascertain their engineering properties. Any special treatment recommended in the preliminary or sub- sequent soil reports not covered herein shall become an addendum to these specifications. No material of a perishable, spongy, or otherwise unstable nature shall be used in the fills. PLACING, SPREADING AND COMPACTING FILL MATERIAL: (a) The sslsctsd fill material shall be placed in layers which shall not excsed six inches (6") whsn compactsd. Each layer shall be spread evsnly and shall bs thoroughly blade-mixed during the spreading to insure uniformity of material and moisturs in sach layer. (b) Whsn the moisture content of ths fill matsrial is below that speci- fisd by the soil snginssr, water shall be added until the moisturs con- tsnt is nsar optimum as determined by the soil enginssr to assure thor- ough bonding during the compacting process. (c) Whsn ths moisturs contsnt of the fill material is above that speci- fisd by ths soil engineer, the fill material shall bs asrated by blading and scarifying, or othsr satisfactory methods until the moisture content is nsar optimum as determined by the soils enginssr. (d) Aftsr sach laysr has been placed, mixed and sprsad svsnly, it shall bs thoroughly compactsd to not lsss than ths spscified maximum density in accordancs with A.S.T.M. D1557-64T. Compaction shall bs by msans of tamping or shespsfoot rollers, multipls-whesl pneumatic-tired rollers, or othsr typss of rollsrs. Rollsrs shall be of such design that thsy will bs abls to compact ths fill to ths spscifisd dsnsity. Rolling of each laysr shall bs continuous ovsr its entire area and the roller shall maks sufficisnt passss to obtain the desirsd density. Ths sntire area to bs filled shall bs compactsd to the specified density. SOIL AND MATERIAL TESTING LABORATORY OF" NORTH COUNTY, INC. -2- (e) Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compacting operations shall be continued until the slopes are stable but not too dense for planting and until there is no appreciable amount of loose soil on the slopes. Compacting of the slopes shall be accomplished by backrolling the slopes in increments .of 3 to 5 feet in elevation gain or by other methods producing satisfactory • results. (f) Field density tests shall be made by the soil engineer for approx- imately each foot in elevation gain after compaction, but not to exceed two feet in vertical height between tests. The location of the tests in plan shall be spaced to give the best possible coverage and shall be taken no farther than 100 feet apart. Tests shall be taken on corner and terrace lots for each two feet in elevation gain. The soil engineer may take additional tests as considered necessary to check on the uniform- ity of compaction. Where sheepsfoot rollers are used, the tests shall be taken in the compacted material below the disturbed surface. No additional layers of fill shall be spread until the field densi·ty tests indicate that the specified density has been obtained. (g) The fill operation shall be continued in six inch (6") compacted layers, as specified above, until the fill has been brought to the fin- ished slopes and grades as shown on the accepted plans. SUPERVISION: Supervision by the soil engineer shall be made during the filling and compacting operations so that he can certify that the fill was made in accordance with accepted specifications. The specifications and soil testing of subgrade, subbase, and base materials for roads, or other public property shall be done in accordance with specifications of the governing agency. SEASONAL LIMITS: No fill material shall be placed, spread, or rolled during unfavorable weather conditions. When the work is interrupted by heavy rain, grading shall not be resumed until field tests by the soil engineer indicate that the moisture content and density of the fill are as previously specified. In the event that, in the opinion of the engineer, soils unsatisfactory as foundation material are encountered, they shall not be incorporated in the grading and disposition will be made at the engineer's discretion. SOIL AND MATERIAL TESTING LABORATORY OF NORTH COUNTY. INC. -3- " ~ED SOIL CLASSIFICATION ~ IDENTIfYING CRITERIA I. II. COARSE GRAINED (lYIore than 50% #200 sieve) GRAVELS (lYIore than 50% #4 sieve but smaller than 3 inches) Non Plastic SANDS (More than 50% smaller than #4 sieve) Non Plastic fINE GRAINED (More than 50% smaller than #200 sieve) Liquid Limit less than 50 Liquid Limit greater than 50 III. HItHLY ORGANIC SOILS GROUP SOIL SYIYIBOL DESCRIPTION GUJ GP GIYI GC SUJ SP SM SC IYIL CL OL MH CH OH PT GRAVEL, well graded gravel- sand mixture, little or no fines. GRAVEL, poorly graded gravel- sand mixture, little or no fines, GRAVEL, SILTY, poorly graded gravel-sand-silt mixtures o GRAVEL, CLAYEY, poorly graded gravel-sand-clay mixture. SAND, well graded, gravelly sands, little or no fines. SAND, poorly graded, gravelly sands, little or no fines. SAND, SILTY, poorly graded sand-silt mixtures, SAND, CLAYEY, poorly graded sand-clay mixtures. SILT, INORGANIC, silt and fine sand, sandy silt or clayey- silt-sand mixtures with slight plastici ty. CLAY, INORGANIC, clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. SILT, ORGANIC, silts and or- ganic silt-clays of low plasticity. SILT, INORGANIC, silts micaceous or dictomaceous fine sandy or silty soils, elastic silts. CLAY, INORGANIC, clays of med- ium to high plasticity, fat clays. CLAY, ORGANIC, clays of medium to high plasticity. PEAT, other highly arganic swamp soils. SOIL AND MATERIAL TESTING LABORATORY OF" NORTH COUNTY, INC.