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1994-4072 G ----------.---.-- ------- -.. ---- Street Address QifL5:__- Category 'fo 7 û f!¡ Name / 13813 Serial # Description Plan ck. # Year ._- ---'---,. 'a onsultants November 29, 1 994 Project No. 25A61.1 To: Ms. Jennifer Hewitson c/o Mr. Jack Buxton 930 Via Mil Cumbres, No. 55 Solana Beach, California 92075 Subject: As-Graded Geotechnical Report, Proposed Single-Family Residence, 1145 Wotan Drive, Encinitas, California Reference: Soils Investigation, Proposed Single-Family Residence, East Side of Wotan Drive, Encinitas, California, by Southland Geotechnical Consultants, dated September 16, 1994 Introduction Southland Geotechnical Consultants has performed field observation and testing services during grading at the s~bject property located at 1145 Wotan Drive, Encinitas, California. This as-graded geotechnical report summarizes our observations and test results and presents recommendations, from a geotechnical standpoint, for design and construction of the proposed single-family residence on the property. Grading Ooerations Grading of the subject property was accomplished during the period of November 22 through 24, 1994. Grading observation and testing of compacted fill were performed by a field technician from our firm who was on site as needed during site grading. Site grading generally conforms with the project grading plan entitled "Grading Plan for: Hewitson Residence, 1145 Wotan Drive, Encinitas, CA 92024," prepared by Tri- Dimenstional Engineering, Inc., dated October 18, 1994. Prior to grading, areas of the site to receive fill were stripped of surface vegetation, debris, and loose soils. Prior to filling, the natural ground was scarified, brought to near-optimum moisture conditions, and compacted to at least 90 percent of the laboratory maximum dry density as determined by ASTM D1557. Fill soils were brought to near-optimum moisture conditions, placed in approximately 8- to 10-inch lifts, and compacted by mechanical means to at least 90 percent of the laboratory maximum dry density as determined by ASTM D1557. . 1238 GREENFIELD DRIVE, SUITE A EL CAJON, CALIFORNIA 92021 . (619J442-8022 . FAX (619J442-7859 Project No. 25A61 .1 Cut-Fill Transition Condition As shown on the grading plan, it was anticipated that site grading would result in a transition (cut-fill) condition underlying the building pad. To reduce the potential for structural damage due to differential settlement across the transition, the cut portion of the pad was overexcavated to a minimum depth of 3 feet below finished pad grade and replaced as moisture-conditioned, properly compacted fill soils. Field and laboratorv Tests Field density tests were performed in general accordance with AsTM D1556 (Sand- Cone Method). The results of the field density tests for the subject property are presented in Appendix A (Summary of Field Density Tests). The approximate locations of the field density tests and the approximate locations of the area of compacted fill placed during grading of the site are presented on Figure 1 (Field Density Test location Map). The laboratory maximum dry density and optimum moisture content of the fill soils were determined in general accordance with AsTM D1557. The results of the laboratory tests are presented in Appendix A (Maximum Density Test Results). CONCLUSIONS AND RECOMMENDATIONS Our observations and field and laboratory test results indicate that the structural fill soils placed during grading of the subject property have been compacted to at least 90 percent relative compaction as evaluated using test methods AsTM D1556 and AsTM D1557. The fill soils placed on site generally consisted of orange-brown, silty fine-grained sand. These soils are similar to soils in the general area found to have very low expansion potential when tested in accordance with UBC Test Standard 29-2. Recommendations for foundations, floor slabs and other construction considerations for the proposed structures are presented in the following sections (and are, in general, reiterated from our referenced report). Foundations Foundations should be designed in accordance with structural considerations and the following recommendations. These recommendations assume that the soils encountered during foundation excavation will have a very low to low expansion 2 S1& Project No. 25A61.1 potential. The proposed residence may be supported on isolated or continuous footings bearing in properly compacted soils at a minimum depth of 12 inches beneath the lowest adjacent grade for a one-story structure or 18 inches for a two-story structure. At these depths, footings may be designed for an allowable soil-bearing value of 2,000 pounds per square foot. This value may be increased by one-third for loads of short duration, such as wind or seismic forces. Footings should have a minimum width of 12 inches, and reinforcement consisting of two No.4 rebars (one near the top and bottom of each footing). Slabs Slabs should have a minimum thickness of 4 inches and be reinforced at mid height in the slab with No.3 rebars at 18 inches on center each way. Slabs should be underlain by a 2-inch layer of clean sand which is underlain by a 6-mil moisture barrier. The potential for slab cracking may be lessened by careful control of water/cement ratios. The use of low slump concrete is recommended. Appropriate curing precautions should be taken during placement of concrete during hot weather. We recommend that a slipsheet or equivalent be used if crack-sensitive flooring is planned directly on the concrete slab. Retaining Walls We recommend that retaining walls be provided with appropriate drainage provisions (Appendix B of the referenced report contains a typical detail for drainage of retaining walls). Appropriate waterproofing treatments and alternative wall drainage products are available commercially. Wall backfill should be compacted by mechanical means to at least 90 percent relative compaction (AsTM D1557). Care should taken when using compaction equipment in close proximity to retaining walls so that the walls are not damaged by excessive loading. siooe landscaoina and Site Drainage Slopes should be provided with appropriate surface drainage features and landscaped with drought-tolerant, slope-stabilizing vegetation as soon as possible after grading to reduce the potential for erosion. Berms should be provided at the tops of fill slopes and brow ditches should be constructed at the tops of cut slopes. We recommend that measures be taken to properly finish grade the lot such that drainage is directed away from foundations (4 percent minimum for a distance of at least 5 feet). Drainage should be directed away from tops of slopes and foundations toward the 3 SGC Project No. 25A61.1 street or collected and tightlined to appropriate discharge points. lot drainage should be directed such that surface runoff on slope faces is minimized. Inadvertent oversteepening of cut and fill slopes should be avoided during fine grading and building construction. landscape requiring a heavy irrigation schedule should not be planted adjacent to foundations. The use of eave gutters with downspouts that discharge to the street or other appropriate discharge point should be considered to control roof runoff. Water, either natural or from irrigation, should not be permitted to pond or saturate the surface soils or flow over the tops of any slopes. Construction Observation and Testina The recommendations provided in this report are based on our understanding of the proposed construction and our evaluation of the onsite soil conditions as tested during site grading. Construction inspection of foundations and field density testing of any additional compacted fill should also be performed by the geotechnical consultant to check that construction is in accordance with the recommendations of this report. If you have any questions regarding this report, please do not hesitate to contact our office. Sincerely, SOUTHLAND GEOTECHNICAL CONSULTANTS ~~~~ Gene Custenborder, CEG 1319 Principal Engineering Geologist Attachments: Figure 1 - Field Density Test location Map Appendix A - Field and laboratory Test Results Distribution: (3) Addressee 4 S1& I I I I I I> . r èi:: \ \ J'" I ~ \ 1"1>' \ i~ ~\ I ~ ì.. \ \ I ¡fSl '. .. \ \ ,0 \ '-I ¡ ~ ~i \ I ~. \ I 8. \, ~, ~ ~~, " % ii." .,. BUILDING STeIl RfTAINING WAil HnGHT O.S IT TO 1.5 FT IIAX LEGEND 58 , Approximate limits of compacted fill placed during ,A grading reported herein FIELD DENSITY TEST LOCATION MAP BASE MAP: Adapted from plan entitled "Grading Plan for: Hewitson Residence, 1145 Wotan Drive, Encinitas, CA 92024," prepared by Tri- Dimentsional Engineering, Inc., dated October 18,1994 Project No. 25A61.1 FIGURE 1 SGC . ~ . Project No. 25A61.1 APPENDIX A - FIELD AND LABORATORY TEST RESULTS SUMMARY OF FIELD DENSITY TESTS Field density tests were performed in general accordance with ASTM D1556 (Sand- Cone Method). The results of the test are presented below: TEST ELEVATION SOIL FIELD DRY MAXIMUM FIELD OPTIMUM RELATIVE (feet) DENSITY DRY DENSITY MOISTURE MOISTURE COMPACTION NO. DATE TYPE (pef) (pef) (%) (%) (%) 1 11/22/94 383 A 119.7 126,2 8,6 8.8 95 2 11/23/94 384 A 124.1 126,2 10.1 8.8 98 3 11/24/94 385 A 122.4 126,2 11.0 8.8 97 4 11/24/94 385 A 114.6 126.2 8,9 8.8 91 5 11/24/94 385 A 115.9 126.2 9.8 8.8 92 MAXIMUM DENSITY TEST RESULTS A maximum dry density and optimum moisture content test was performed on a representative sample of the fill soils. The test was performed in general accordance with ASTM D1557. The results of the test are presented below: SAMPLE MAXIMUM OPTIMUM NUMBER SAMPLE DESCRIPTION DRY DENSITY MOISTURE (pcf) (%) A Orange-brown, silty, 126.2 8.8 fine-grained sand (sM) S1& Tri- Dimensional Engineering, Inc. November 28, 1994 City of Encinitas 505 Vulcan Drive Encinitas, CA 92024 Re: Hewitson Residence 1145 Wotan Encinitas, CA Gentlemen: Tri-Dimensional Engineering, Inc. certifies the grading for the house pad for the above captioned project has been completed in substantial confonnance with the approved grading plan. The a) line and grade of all engineered drainage devices; b) location and slope ratios of all manufactured slopes; and c) construction of earthen benns and positive building pad drainage are in confonnance with the approved plans. The building location was staked in confonnance with the approved plans and does not encroach on any building setback lines. Sincerely, Tti1DimeDSi.pp.~.l,: Ê.', ngID.., eeriqg. ' Inc. I' (! I \ .., f ;' -v ,f', --. ,,' .( , ~ " " ' '!..- , " .'- ! ,,/,/.j,'\./ ..' lJc...~v~-'- II., v - Ernest Grabbe, RCE cc: Jack Buxton P. 0, Box 791 . Poway, CA 92074. (619) 748-4306. Fax (619) 748-4371 . . S G C Sou hland Geotechnical Cons ftan s /' SOILS INVESTIGATION PROPOSED SINGLE-FAMilY RESIDENCE EAST SIDE OF WOTAN DRIVE ENCINITAs, CALIFORNIA Project No. 25A61 September 16, 1994 ¡ n I ;',.1 ',c, , , h.. 1>-I)pl: !;.¡I;\>il¡CI...," UlO l'J ~'!J c, I "; ,",'! ",' , --'" ""'I I .. -' '-.. j ¡ t , ¡j~ OCT 20 1994'--" ENG!~',-~f=QI~IG S~RV'IC . ~"ll. i:: E'"' CITY OF ENCif\lITj-'ì.S -;:, Prepared for: MR. KEVIN FARREll Farrell Design Associates Inc. Architects 2211 Cambridge Avenue, Suite B Cardiff, California 92007 . 1238 GREENFIELD DRIVE, SUITE A EL CAJON, CALIFORNIA 92021 . (619J442-8022 . FAX (619J442-7859 S G C Southland Geotechnical Consultants September 16, 1994 Project No. 25A61 To: Farrell Design Associates Inc. Architects 2211 Cambridge Avenue, Suite B Cardiff, California 92007 Attention: Mr. Kevin Farrell Subject: Soils Investigation, Proposed Single-Family Residence, East Side of Wotan Drive, Encinitas, California Introduction In accordance with your request, Southland Geotechnical Consultants has performed a soils investigation for the proposed single-family residence at the subject property. This report presents a summary- of our studies and provides our recommendations, from a geotechnical standpoint, relative to the proposed development. Puroose and scooe The purpose of our investigation was to evaluate the soil conditions at the site and provide recommendations relative to the proposed construction. The scope of our investigation included the following: Review of project plans and geotechnical literature for the site and vicinity. A list of the documents reviewed is provided in Appendix A. Field reconnaissance to observe the existing site conditions. Investigation of the near-surface soil conditions by manually excavating and sampling an exploratory pit. Geotechnical analysis of the data obtained. Preparation of this report summarizing the results of our soils investigation and presenting recommendations, from a geotechnical standpoint, for the proposed development. . 1238 GREENFIELD DRIVE, SUITE A EL CAJON, CALIFORNIA 92021 . (619J442-8022 . FAX (619J442-7859 Project No. 25A61 Proiect Descriotion The subject property consists of an undeveloped, relatively level lot located on the eastern side of Wotan Drive in Encinitas, California (see Figure 1). Developed residential properties exist to the north, east and south of the site. Site vegetation consists of grasses, some shrubs and trees. lawn and yard trimmings have been dumped on portions of the property. Rodent burrows were also observed on the property. We understand that proposed development at the subject property will consist of the construction of a two-story, wood-frame, single-family residential structure and a one- story, wood-frame, detached garage. The structures will utilize conventional isolated and/or continuous footings with slab-on-grade floors. Site grading is not currently proposed at the site. Building loads are assumed to be typical for this type of relatively light construction. Soil Conditions Our subsurface investigation consisted of one exploratory pit near the northwestern corner of the proposed residence. The exploratory pit was manually excavated into formational materials' and a sample of the near-surface soils encountered was obtained. Based on our review of a geologic map and our onsite observations, the subject property appears to be underlain by Quaternary-aged marine terrace deposits consisting of silty fine sandstone. A topsoil veneer is developed from the weathering of, and is gradational with, the underlying terrace deposits. The topsoil is anticipated to be found to a depth of approximately 1 to 1.5 feet below the existing ground surface. The potentially compressible topsoil is not considered suitable for the support of structural loads in its present condition. The topsoil encountered in our exploratory pit consisted of silty fine sand and is similar to soil in the general site vicinity found to have a very low expansion potential when tested in general accordance with UBC Standard No. 29-2. Ground Water Indications of a near-surface ground water table were not observed or encountered during our investigation. Ground water is not anticipated to a constraint to the proposed development. 2 SGC Project No. 25A61 Conclusions and Recommendations Based on the results of our soils investigation, it is our opinion that construction of the proposed structures is feasible from a geotechnical standpoint. The following sections provide recommendations, from a geotechnical standpoint, which should be considered for design and construction of the proposed project. If site earthwork is performed, it should be in accordance with the following recommendations and the Recommended Earthwork Specifications contained in Appendix B. Site Preoaration No site grading is currently anticipated for the proposed development. Prior to construction activities at the site, the building areas should be cleared of vegetation, dumped lawn trimmings, debris and loose topsoil. Vegetation and loose debris should be properly disposed of off site. Holes resulting from removal of buried obstructions which extend below finished site grades should be filled with properly compacted fill soils. Structural Fill Placement Areas to receive fill and/or other surface improvements should be scarified to a minimum depth of 6 inches, brought to near-optimum moisture conditions, and recompacted to at least 90 percent relative compaction, based on laboratory standard AsTM D1557. Fill soils should be brought to near-optimum moisture conditions and compacted in uniform lifts to at least 90 percent relative compaction (AsTM D1557). The optimum lift thickness to produce a uniformly compacted fill will depend on the size and type of construction equipment used. In general, fill should be placed in loose lift thicknesses not exceeding 8 inches. Foundation Recommendations We understand that the proposed residence and garage will consist of wood-frame structures supported on conventional isolated and/or continuous footings with slab-on- grade floors. Foundations and slabs should be designed in accordance with structural considerations and the following recommendations. These recommendations assume that the soils encountered during foundation excavation will have a very low to low expansion potential. 3 Sf& Project No. 25A61 The proposed structures may be supported on isolated or continuous footings bearing in firm, natural soils at a minimum depth of 12 inches beneath the lowest adjacent grade for a one-story structure (or 18 inches for a two-story structure). At these depths, footings may be designed for an allowable soil-bearing value of 2,000 pounds per square foot. This value may be increased by one-third for loads of short duration, such as wind or seismic forces. Footings should have a minimum width of 12 inches, and reinforcement consisting of two No.4 rebars (one near the top and bottom of each footing). Slabs should have a minimum thickness of 4 inches and be reinforced at midheight in the slab with No.3 rebars at 18 inches on center each way (or No.4 rebars at 24 inches on center each way). Slabs should be underlain by a 2-inch layer of sand which is underlain by a 6-mil moisture barrier. The potential for slab cracking may be lessened by careful control of water/cement ratios. The use of low slump concrete is recommended. Appropriate curing precautions should be taken during placement of concrete during hot weather. We recommend that a slipsheet or equivalent be used if crack-sensitive flooring is planned directly on the concrete slab. Footings and slabs founded in firm, natural soils may be designed for a passive lateral bearing pressure of 350 pounds per square foot per foot of depth. A coefficient of friction against sliding between concrete and soil of 0.4 may be assumed. These values may be increased by one-third when considering loads of short duration, such as wind or seismic forces. . Surface Drainage Drainage at the site should be directed away from foundations and collected and tightlined to an appropriate discharge point. Consideration may be given to collecting roof drainage by eave gutters and directing it away from foundations via non-erosive devices. Water, either natural or from irrigation, should not be permitted to pond, saturate the surface soils, or flow over the tops of any slopes. Seismic Considerations The principal seismic considerations for most structures in southern California are surface rupturing of fault traces and damage caused by ground shaking or seismically- induced ground settleme,nt or liquefaction. The possibility of damage due to ground rupture is considered minimal since no active faults are known to cross the site. 4 SGC Project No. 25A61 The seismic hazard most likely to impact the site is ground shaking resulting from an earthquake on one of the major active regional faults. The effects of seismic shaking can be reduced by adhering to the most recent edition of the Uniform Building Code and current design parameters of the Structural Engineers Association of California. Because of the very dense nature of the underlying soils and absence of a near-surface ground water table, it is our opinion that the potential for liquefaction or seismically- induced ground settlement at the site due to an earthquake is very low. Construction Observation and Testing The recommendations provided in this report are based on preliminary project plans and subsurface soil conditions exposed during our investigation. The interpolated subsurface conditions should be checked in the field during construction. Foundation excavation observation and field density testing of compacted fill should also be performed by the geotechnical consultant to check that cònstruction is in accordance with the recommendations of this report. If you have any questions regarding our report, please do not hesitate to call. Sincerely, SOUTHLAND GEOTECHNICAL CONSULTANTS C~~~;O2 Project Engineer Attachments: Distribution: (3) Addressee 5 SGC SITE LOCATION MAP iN Project No. 25A61 Scale (approximate): 1 inch = 2,200 feet Base Map: Pleistocene Marine Terrace and Eocene Geology, Encinitas and Rancho Santa Fe Quadrangles, San Diego County, California, by Leonard Eisenberg, 1 983 FIGURE 1 SGC APPEN DIX A REFERENCES 1. Eisenberg, L., 1985, Pleistocene marine terrace and Eocene geology, Encinitas and Rancho Santa Fe quadrangles, San Diego County, California, in Abbott, P.L., ed., On the manner of deposition of the Eocene strata in northern San Diego County: San Diego Association of Geologists fieldtrip guidebook. 2. Farrell Design Associates Inc. Architects, undated, untitled site plan. 3. Greensfelder, R.W., 1974, Maximum credible rock acceleration from earthquakes in California: California Division of Mines and Geology, Map Sheet 23. 4. Hart, E.W., 1992, Fault-rupture hazard zones in California: California Division of Mines and Geology, Special Publication 42, revised. SI& RECOMMENDED 'EARTHWORK SPECIFICATIONS 1.0 General Intent These specifications are presented as general procedures and recommendations for grading and earthwork to be used in conjunction with the approved grading plans. These general earthwork specifications are considered a part of the recommendations contained in the geotechnical report and are superseded by recommendations in the geotechnical report in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations which could supersede these specifications or the recommendations of the geotechnical report. It shall be the responsibility of the contractor to read and understand these specifications, as well as the geotechnical report and approved grading plans. 2.0 Earthwork Observation and Testina Prior to grading, a qualified geotechnical consultant should be employed for the purpose of observing earthwork procedures and testing fill placement for conformance with the recommendations of the geotechnical report and these specifications. It shall be the responsibility of the contractor to keep the geotechnical consultant apprised of work schedules and changes, at least 24 hours in advance, so that he may schedule his personnel accordingly. No grading operations shall be performed without the knowledge of the geotechnical consultant. The contractor shall not assume trlat the geotechnical consultant is aware of all site grading operations. It shall be the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes and agency ordinances, recommendations of the geotechnical report, and the approved grading plans. If, in the opinion ,of the geotechnical consultant, unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of work less than recommended in the geotechnical report and the specifications, the consultant will be empowered to reject the work and recommend that construction be stopped until the conditions are rectified. 3.0 Preoaration of Areas to be Filled 3.1 Clearina and Grubbina: Sufficient brush, vegetation, roots, and all other deleterious material should be removed or properly disposed of in a method acceptable to the owner, design engineer, governing agencies and the geotechnical consultant. ' SGC .. ,,- 3.2 3.3 3.4 3.5 3.6 3.7 The geotechnical consultant should evaluate the extent of these removals depending on specific site conditions. In general, no more than one percent (by volume) of the fill material should consist of these materials. In addition, nesting of these materials should not be allowed. Processina: The existing ground which has been evaluated by the geotechnical consultant to be satisfactory for support of fill, should be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory should be overexcavated as specified in the following section. Scarification should continue until the soils are broken down and free of large clay lumps or clods and until the working surface is reasonably uniform, flat, and free of features which would inhibit uniform compaction. Overexcavation: Soft, dry, organic-rich, spongy, highly fractured, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be overexcavated down to competent ground, as evaluated by the geotechnical consultant. For purposes of determining pay quantities of materials overexcavated, the services of a licensed land surveyor or civil engineer should be used. Moisture Conditionina: Overexcavated and processed soils. should be watered, dried, or blended as necessary to attain a uniform near- optimum moisture content as determined by test method ASTM 01557. Recomoaction: Overexcavated and processed soils which have been properly mixed, screened of deleterious material, and moisture- conditioned should be recompacted to a minimum relative compaction of 90 percent as determined by test method AsTM D1557. Benchina: Where fills are placed on ground sloping steeper than 5:1 (horizontal to vertical), the ground should be stepped or benched. The lowest bench should be a minimum of 15 feet wide, excavated at least 2 feet into competent material as evaluated by the geotechnical consultant. Ground sloping flatter than 5:1 should be benched or otherwise overexcavated when recommended by the, geotechnical consultant. Evaluation of Fill Areas: All areas to receive fill, including processed areas, areas of removal, and fill benches should be evaluated by the geotechnical consultant prior to fill placement. Sl& 4.0 Fill Material 4.1 4.2 4.3 General: Material to be placed as fill should be sufficiently free of organic matter and other deleterious substances, and should be evaluated by the geotechnical consultant prior to' placement. Soils of poor gradation, expansion, or strength characteristics should be placed as recommended by the geotechnical consultant. Oversize Material: Oversize fill material, defined as material with a maximum dimension greater than 6 inches should not be buried or placed in fills unless the location, materials, and methods are specifically recommended by the geotechnical consultant. Imoort: If grading operations include importing of fill material, the import material should meet the requirements of Section 4.1. Sufficient time should be given to allow the geotechnical consultant to test and evaluate proposed import as necessary, prior to importing to the site. 5.0 Fill Placement and Comoaction 5.1 5.2 5.3 5.4 Fill lifts: Fill material should be placed in areas properly prepared and evaluated as acceptable to receive fill. Fill should be placed in near- horizontal layers approximately 6 inches in compacted thickness. Each layer should be spread evenly and thoroughly mixed to attain uniformity of material and moisture content throughout. Moisture ConditioninQ: Fill soils should be watered, dried or blended as necessary to attain a uniform near-optimum moisture content as determined by test method AsTM 01557. Comoaction of Fill: After each layer has been evenly spread, moisture conditioned, and mixed, it should be uniformly compacted to not less than 90 percent of maximum dry density as determined by test method AsTM D1557. Compaction equipment should be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified degree and uniformity of compaction. Fill siooes: Compaction of slopes should be accomplished, in addition to normal compaction procedures, by backrolling slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the fill, including the embankment face should be at least 90 percent as determined by test method ASTM D1557. S1& 5.5 Comoaction Testina: Field tests of the moisture content and degree of compaction of the fill soils should be performed by the geotechnical consultant. The location and frequency of tests should be at the consultant's discretion based on observations of the field conditions. In general, the tests should be taken at approximate intervals of 2 feet in elevation gain and/or each 1,000 cubic yards of fill placed. In addition, on slope faces, as a guideline, one test should be taken for each 5,000 square feet of slope face and/or each 10-foot interval of vertical slope height. 6.0 subdrain Construction 'Subdrain systems, if recommended, should be constructed in areas evaluated for suitability by the geotechnical consultant. The subdrain system should be constructed to the approximate alignment in accordance with the details shown on the approved plans or provided herein. The subdrain location or materials should not be modified unless recommended by the geotechnical consultant. The consultant may recommend modifications to the subdrain system depending on conditions encountered. Completed subdrains should be surveyed for line and grade by a licensed land surveyor or civil engineer. 7.0 Excavations Excavations and cut slopes should be evaluated by the geotechnical consultant during grading. If directed by the geotechnical consultant, further excavation, overexcavation, and/or remedial grading of cut slopes (i.e., stability fills or slope buttresses) may be recommended. 8.0 Quantitv Determination The services of a licensed land surveyor or civil engineer should be retained to determine quantities of materials excavated during grading and/or the limits of overexcavation. Sf& .., KEY AND BENCHING DETAILS FILL SLOPE GRO"e;6'~~~ ACE T ;~gJ~: ~ ~ H J z $~:;~t"li~ .:j::~:~-::~--: ; I, --::~:§:~~::j:~=--- ~---~ ~:P;=~ ~ --, ï~;: -: -:\ ,-.JJ ~ø~~~~ "'BENCH :~==2~N.~::~WI\ 2' MIN.C"15' MIN.---J KEY ILOWES+----¡ DEPTH BENCH (KEY) REMOVE UN SUIT ABLE MA TERIAL PROJECT 1 TO 1 UNE FROM TOE OF SLOPE TO COMPETENT MA TëRIAL - Õ~PACTEO~g - -== :f :f:f :f:[ ':! ~ ~ -------~---- - --g ~- ~ -==::?§:-:: ~-:=- - -' EXISTING --=~~~ 'IVA GROUND SURFA~E _~~~-":JI-= -- ---~g~ "'::JlI; '-- - --=-~.:-_;.-= BENCH ----- ~ -~--------.:::-- - - - - ::;-:_-:2~~1~:ti;:- ----- - -- . ..- ..- r.15' MINrl .......""'" ,'" 2' LOWEST ./' - ...~ MIN. BENCH KEY (KEY) DEPTH CUT SLOPE (TO BE EXCAVATED PRIOR TO FILL . PLACEMENT) / ",/' EXISTING / / ' GROUND // SURFACE~/ / r :?' / ~l~ CUT SLOPE / ¿ \\\ (TO Be eXCAVATED, / PRIOR TO FILL -~:f.:#J PLACEMENT) ::ï::-::---:~ _~~---REMOVE --:~=::::~~ U~SUIT ABLE --:~--:--~.!!! MA TERIAL - .=.-.T-.----ø:--:>:. ~ ~cf(~---- ~:t~ ~~~=~~=~ ~BENCH --------~---~i,\ (. - -j;';:i=f:-j:====i=~; , -==~~~7-~~::~'" ~ S' MIN.--I 2' MIN.! &':OWEST I KEY DEPTH BeNCH . (KEY) REMOVE UNSUITABLE MATERIAL FILL-OVER-CUT SLOPE , CUT-OVER-FILL SLOPE NOTE: Sack drain may be recommended by the geotechnical consultant based on actual field conditions encountered. Bench dimension recommendations may aJso be altered based on field conditions encountered. SGC TRANSITION LOT DETAILS CUT-FILL LOT EXISTING GROUND SURFACE 1- --- ..---- -- -- --- -- 5' -- -- ~............. MIN. '~---------:::..~:-:::_~~~~~*-::::::::-::-~-:--:..-~-::-::-:--- ---::=::_-:-::-::-:-:-:-::::::----- H ... =1 '-:~~~~?A CI~~~::3:3=~~~~;-~~~!,-:..-_-::-!~i=i=#j:i=~~:j:j:i=j:~j:::::~::~ 36M IN. ._--,Flk1..-------~-------' e. ,¡.þ.. --- - Ifl(-ell 1/ IIt-II\---¡- ~~§3::~~~"t\~--~~~~~:~:f~:t - - - f :?-~~j:-O--~i' ~!t~-:..=-=:~---::_---~~~~:--::-:- OVEREXCA VA TE '~~~~s.~-.:::-~~-j:::;. - AND RECOMPACT "-i=::-::-i-::§----- _-:..-:::--~~------ , IIL=V¡f1l COMPETENT BEDROCK, / ----- OR MATERIAL EVALUATED ~ I' BY THE GEOTECHNICAL CONSULTANT CUT LOT EXISTING GROUND SURFACE J-- ---- --- -- ---- -- -- I ...,,- --- --~UN~~~T~~7.E~ ~..--- --- 5'- - --- MATERIAL --- MIN. '~-i:-:-'_-:-:: -::-::-::~~:t- ~~*-:~ =-~----::-_- ~-::-?::- §-: - - ~-::~ -::-:: : -::-::-:: -::-:: ~ -::-:: -: -:: -::-:: -::-:: ~ -:: -:: -:: ~ ~~~ ~ 3 6. M IN'" ,:":;;;::' --:-::-::-°::c 0 M PA C TED ~--::-:-----------------~.::-_-=::::~:-::r:--:..-:..-_-:..---:..-:..-:..-:..-:..-_-:..-:..-:..-:'-:"-:"-_-:'---=--=--: . '.~j::=k-:-::-:FILL -:..-=--=--:.~~=~:=--- 1;'I/~I~_-:/~---- ---:"-:"-_-:"-:"--~-:"~~~~-~];~I~----- - - - T ::f~~~~~~J~¡¡if:~-~~~~:¡:=3:= -, - OVEREXCA~ATE . . ::':::::E.f~~~~~7~~ AND R E COM PAC T COMPETENT BEDROCK ,/ ~R MATERIAL EVALUATED~ BY THE GEOTECHNICAL CONSUL TANT --- -- "'NOTE: Deeper or laterally more extensive overexcåvation and recompaction may be recommended by the geotechnical consultant based on actual field conditions encountered and locations of proposed improvements SGC ROCK DISPOSAL DETAIL PINiSH ~ACe ------- -....- -- - ---- SLO PE FA C E ------:;.:;.:;.:;. :;.:;.~ ~ ~ ~ ~.;:.;:~"-,:.;:-- _c: = -----~-:;- ~ ":~-' . - ~ ~ ~fiJJj~iiJ~fffflffll:~J~ . - ~ Š T M ï Ñ -- -:.. -:.. -- - CY'"'r-..-=£t -- -- -=--- ---- -- n:=-:-:=- -:.. -:.. -=- -=- -:: -::-::~---_-! - --:=-::- :~~j:~ -:..:f~ ~~~~-=- --- -i~~~~ ~~~~=§ _-:-g::~ --::~-:=t ~~::-:=-:=-:=-:=-::=- :------~ 9 M PAC TED FILk ~-j:j:j _-::~~~~~~~~~ - :I~~~~~~¡¡l¡~¥~~~~? _-:..--------~----------_-:..---------- --":'5' MtN -~-:.-:..-:..----::;t::- GRANULAR SOIL (S.E..?: 30) TO BE CENSIFIED IN PLACE BY FLOOCING DETAIL --------------- -------------- --------------- nr~UC)r]- - - - -:-- - - -.- - - -- --------------- -------------- --------------- TYPICAL PROFILE ALONG WINDROW 1) Rock with maximum dimensions greater than 6 inches should not be used within 10 feet vertically of finish grade (or 2 feet below depth of lowest utility whichever is greater). and 15 feet horizontaJly of slope faces. 2) Rocks with maximum dimensions greater than 4 feet should not be utilized in fills. 3) Rock placement, flooding of granular soil, and fill placement should be observed by the geotechnical consultant. . 4) Maximum size and spacing of windrows should be in accordance with the above details Width of windrow should not exceed 4 teet. Windrows should be staggered verticaJly (as depicted). S) Rock should be placed in excavated trenches. Granular soil (S.E. greater than or equal. to 30) should be flooded in the windrow to completely fill voids around and beneath rocks. SGC .. RETAINING WALL DRAINAGE DETAIL RETAINING WALL WALL WATERPROOFING PER ARCHITECT'S SPECIFICA TlONS FINISH GRADE SOIL BACKFILL, COMPACTED TO 80 PERCENT RELATIVE COMPACTION* - --- . -- - --- -- -- - --- -------- -------------- -- --------- ------------- --- -------- ------------ --- -------- ----------- --- ------- ----------- liitillllitt ~~~'j:-- 3/4--1-1/2- CLEAN GRAVEL ** 4- (MIN.) DIAMETER PERFORATED PVC PIPE (SCHEDULE 40 OR EQUIV ALENT) WITH PERFORATIONS ORIENTED DOWN AS DEPICTED MINIMUM 1 PERCENT GRADIENT TO SUITABLE OUTLET ------------ ----- - -. ------------------------------ ------------------------------ ------------------------------ ------------------------------ --: -::=;'=;~~~~~ t ~-~~~=~~~~~~~ ~ ~ W ALL FOOTING NO.T TO SCALE SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size % Pass inq , 1" 100 3/4" 90-100 3/8" 40-100 No.4 25-40 No.8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 Sand Equivalent>75 COMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE GEOTECHNICAL CONSULTANT * BASED ON ASTM D 1557 * * IF CAL TRANS CLASS 2 PERMEABLE MATERIAL (SEE GRADATION TO LEFT) IS USED IN PLACE OF 3/4--1-112- GRAVEL, FILTER FABRIC MAY BE DELETED. CAL TRANS CLASS 2 PERMEABLE MATERIAL SHOULD BE COMPACTED TO 90 PERCENT RELATIVE COMPACTION * NOTE:COMPOSITE DRAINAGE PRODUCTS SUCH AS ~RADRAJN lOR J-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR CLASS 2. INSTALLATION SHOULD BE PERFORtvED IN ACCORDANCE '.MTH MANUFACTURER'S SPECIACA TION5. .SGC . ~~Ì"Ì' ~'fiË -"'1 f ;<!i~'~ '¡';¡¡~~CJ:~~~ ~_:o þ; :~~;;;t c;; l ]E'.~ ~~:'1f~;~i 1!i~~)¡!I!i;i; 1i¡'¡'5;~J!';f!¡:J.t; ~'E ;££!!'Æ ~ ": ¥: ~~¡;¿:!J~ ¡;,;. ?,~~'iF. 'þ"': ¿~,: ~;;,~-': ,::;~ :', 'i ~ i;'!i~,J~;;¡;:j¿. 'i:::~ !f~;;;f §~w f G:~!iÔ~:t;, ;;i;;;i .; j ~EB' . ¡: .' i . " ~27859 SOUTHLAND GEOTECH. 782 P02 = 21'~ 1~ 't October 21,1994 Project No. 25A61 To: Farrell De ign Associates Inc. Architects 221.1 cã bridge Avenue, Suite B Cardiff, C lifornia 92007 Reference: Soils Inv stigation, Proposed Single-Family Residence, East Side of Wotan rive, Encinitas, California, by Southland Geotechnical Consults s, dated September 16, 1994 Geotechni 'a I Review of Grading Plan, Hewitson Residence, 1 145 Wotan Drive, En initas, California Attention: Subject: Introduction As requested, South I nd Geotechnical Consultants has performed a geotechnical review of the grading Ian for the subject site. The purpose of our review was to check that the rec mmendations presented in our referenced geotechnical investigation were in co porated into the grading plan. This report presents the results of our geotechnical re iew. We have reviewed She t 1 of 1 of the project grading plan entitled "Grading Plan for: Hewitson Residence, 145 Wotan Drive, Encinitas, CA 92024," prepared by Tri- Dimensional Engineerin , Inc, dated October 18, 1994. We have also reviewed the referenced soils invest gation report for the project,' dated September 16, 1994. Our review of the refer nced grading plan indicates that site earthwork will consist of approximately 200 cu ic yards of cut/fill grading to create a relatively level pad for construction of the pr posed residence and detached garage. Although it was our original understanding that no site grading was planned¡ recommendations for site earthwork were ¡nclud d in our referenced soils investigation report. Based on our review, it appears that the recommendations presented in our referenced soils report are applic ble to the proposed grading plan. In addition, the following recommendations were developed based on our review of the project grading plan and should also be consid red for site development. ,( ,"~<¡;~':;~ii?>'!i'i~¡¡;;';¡¡i«!!1i!e'~'f~¿......- . h-:- ~ ,. _...¿7859 SOUTHLRND GEOTECH. 782 P03 OCT 21 '94 10:33 Project No. 25A61 . I Tn' . n - Our review of the project grading plan indicates that site grading may ra ult in a transition (cut-fill) condition in the building pad underlying the p oposed residence. To reduce the potential for damage to the structure due to differential settlement across the transition, we recommend that the cut porti n of the lot be overexcavated to a minimum depth of 3 feat below finished p d grade, moisture-conditioned, and recompacted to at least 90 percent re/at ve compaction (A5TM 01557). The overexcavation should extend a minimu of 5 feet outside of the perimeter of the proposed residence. rue ¡nO S rv i an ti - We recommend that the onsite geotechnical can itions be checked in the field during grading and construction. Construction ins ction of foundations, subdrains, and field density testing of compacted fill, a d backfill should be performed by the geotechnical consUltant to check that co struction is in accordance with the recommendations of the geotechnical rep ft. The recommendations p esented in our referenced report including those regarding site earthwork are stin applic bJe. If you have any questions regarding our report, please do not hesitate to call. Sincerely, SOUTHLAND GEOTEC NfCAL CONSULTANTS ~~~o Gene Custenborder, CE Principal Engineering Ge Distribution: 1319 lagist (1) A dressee (, ) r. Jack Buxton via Fax (') C ty of Encinitas via Fax 2 ;~- ~------------------------------------------------------------------- 10-20-1994 07:17AM FROM Tri-Dimensional Engr'g TO 7555426 P.03 -,._-" Tri-Dimensional Engineering, Inc. I """ October 18, 1994 City of Encinitas 505 Vulcan Street Encinias, CA 92024 Re: Hewitson Residence Hydrology / Hydraulics Gentlemen: The grading of the lots to the east and north of 1145 Wotan Drive have rerouted the existing off-site storm water flows away ITom the tract. The on-site flows flow southwesterly toward Wotan Drive and will not be significantly changed by the proposed grading. Sincerely, Tri~t Ernest Grabbe, RCE ,---., " , , ,,' 'r' t,,' O'i lL; Ii" j"), ii, ¡V,: ;,~" I . -~ ,~) ~:: U 'el I::, ip . ., ¡ ',-' '-" OCT 2 0 1994 ENGINEERING SERVICES CITY OF ENC!N!TAS p. O. Dox 791 . Poway. CA 92074. (619) 748-4306 . fax (619) 745-4J71