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HomeMy WebLinkAboutPD 2019-0029; 3559 CORTE ESPERANZA ADDITION; PROPOSED RETAINING WALL SITE; 2019-11-06I,' M M" ow P.O. Box 1195 Lakeside, California 92040 November 6, 2019 gv, (619) 443-0060 Britt Styr & Allen Chalepas 3559 Corte Esperanza Carlsbad, California 92009 RECORD Copy Initial Date SUBJECT: File No. 1148A4-19 SITE INSPECTION Proposed Retaining Wall Site 3559 & 3561 Corte Esperanza City of Carlsbad Dear Ms. Styr & Mr. Chalepas: SCOPE In accordance with your request, a Site Inspection has been performed at the subject site. The purpose of this investigation was to examine existing site conditions and provide engineering recommendations for the proposed accessory dwelling unit and garage both one story with slab construction and restraining walls up to 6 feet in height, and retaining walls up to six feet in height. The proposed accessory dwelling unit will be located on the northeast side of the property and theproposed garage will be on the north end of the property by the driveway. There will be a retaining wall between the two structures. The estimated loading for continuous footings is 120 psf per foot and for isolated footings the estimated maximum loading is 800 psf. FIELD INSPECTION In order to accomplish this purpose, a representative of this firm visited the site, reviewed the topography and site conditions and visually and textually classified the surface and near surface soils. Representative samples of the on-site soils were obtained from a test excavation approximately 5 feet in height and tested for density, shear strength and expansive characteristics. 1 Britt Styr & Allen Chalepas File No. 1148A4-19 November 6,2019 SITE CONDITIONS The subject site is located on the southeast side at the end of the east cul-de-sac on Corte Esperanza. The site is relatively level in the house pad area and approximately 2 feet above street level. There is a 2:1 approximately 10 foot high slope at the rear or southeast portion of the property sloping down into the open space. There is an approximate 20+/- foot high engineered fill upsiope along the northeastern property line. The property is occupied by a single family residence, swimming pool and a covered patio. Neighboring properties are occupied by residential structures. Fill materials for landscaping were approximately 12 inches in depth; soft fill soils were encountered to a depth of 5 feet during the course of this inspection. Based on a review of the grading plans, it does not appear that the proposed temporary cuts will undermine the improvements on the neighboring property. The temporary cuts if required, should comply with OSHA standards. The proposed cuts will be a minor disturbance to the slope. Any deviation and we should be contacted. A stability fill slope with a buttress keyway was created on the cut slope of the north northeastern slope. The stability fill slope key was excavated along the toe of slope a minimum of 5 feet in depth and a minimum of 15 feet wide. A subdrain was placed at the bottom of the stability fill backcut for the slope between lots 34 to 38 and has been outletted into the open space south of the subject site. The approximate location of this subdrain is shown on Plate I. This subdrain should be located a minimum of 5 feet in depth and is surrounded by 3 cubic feet of clean /4 inch gravel and wrapped in Marifi 140N geofibric. During the grading excavation, if the contractor encounters the subdrain, care should be taken to not damage it. Any damage should be repaired and replaced in kind. GEOLOGY AND SOIL CONDITIONS Soils encountered in the test exploration fill soils consisting of loose, dark brown, sandy loam to approximately 1 foot in depth. These surface soils were underlain with soft, grey to tan, silty sandy clays sands to the bottom of the excavation approximately 5 feet in depth. Density of the soils was determined by visual inspection and probe method. Please see Plate II for more detail. Reference to the geologic and Landslide Hazard Identification Map of the Rancho Santa Fe Quadrangle Tan (1986) indicates that the property is underlain (beneath any fill that may be present) by the Scripps Formation. This Eocene-aged geologic unit is composed of interbedded white to gray brown medium-grained sandstone and interbeds of brown claystone and sandy claystone. Bedding, except where affected by faulting, generally dips to the west and southwest at inclinations of 5 to 15 degrees. For additional geologic statement about the existing soil type see 3.0 Engineering Geologic Summary, subsections 3.1 through 3.5 of the referenced Leighton Engineering Report. 2 Britt Styr & Allen Chalepas File No. 11 48A4-19 November 6, 2019 Some of the soils we encountered were considered to be critically expansive with respect to change in volume with change in moisture content. CONCLUSIONS AND RECOMMENDATIONS A representative sample of the foundation soil was remolded to 90% of maximum dry density. Based on the following test results, a safe allowable bearing value of at least 1500 pounds per square foot based on 12 inch deep footings may be used in designing the foundations and slab for the proposed structures. This is for bearing value only and not an indication of proposed footing depth. This value may be increased by one third for wind and/or seismic loading. This value may be increased by 20 percent for each additional foot of depth and or width to a maximum of 3 times the designated value. The tests were performed in general accordance with ASTM standards and other accepted methods. The critically expansive soils encountered during this inspection should not be used to support the proposed structure. It is our recommendation that these soils in the proposed building areas be removed to a minimum depth of 3 to 5 feet and the critically expansive soils exported. It is our understanding that the proposed excavation will extend 5 feet in depth for the restraining walls and the proposed structures and 3 feet in depth for the patio area. The excavation should extend at least 5 feet outside the proposed building footprints and a minimum of 3 feet on the side where the open space limits space. Prior to placing fill, Tencate Mirafi RS280i should be installed on the native soils per manufacturer's instructions. Import soils that are not detrimentally expansive (El <30) should be placed and compacted to 90 percent compaction in accordance with the Grading Specifications in this report. The import soils should used for the proposed retaining wall backfill. Any organic or other deleterious material that may be encountered should be removed prior to recompaction. During the grading operation, the critically expansive soils encountered should not be placed within 3 feet of finish grade. Any critically expansive soils within the top 3 feet must be removed from the building area to achieve uniformly non-expansive soils for the building foundation. It is our understanding that the retaining wall will be constructed separate or isolated from the proposed structures. If the footings for the retaining wall will be founded in the critically expansive onsite soils, the area under the footing should be lined with 3 inch minus angular crushed rock to a depth of 6 inches and compacted in. We should be present to observe the placement and compaction of the rock. If this is not the case, the soils under the wall footings must be removed and replaced in accordance with the previous recommendations. The contractor has the responsibility to consider 3 Britt Styr & Allen Chalepas File No. 11 48A4-19 November 6, 2019 the construction stage measurement to determine if temporary shoring is required. If it is required, he should consult the engineer of record for the design. Structural footings should be founded on a uniform soil type and entirely on uniformly placed on structural fill or competent native soils. The estimated maximum values for the Total Settlement is 1 ¼ inch and for the Differential Settlement is 5/8 inch. Once the critically expansive soils are capped with nonexpansive soils the following recommendations may be used for the proposed structures and restraining walls. Conventional spread footings founded a minimum of 24 inches below lowest adjacent grade and having a width determined by the allowable soil bearing value as detailed above are recommended for foundation support. Footing widths should be at least 12 inches for continuous footings and 24 inches for square footings due to practical considerations as well as Building Code requirements. These recommendations are based upon the soil type encountered and do not take into consideration the proposed bearing load. The actual footing width should be determined by the design engineer based on his design load. Footings for the proposed accessory dwelling structure should be placed a minimum of 8 feet back from the top of slope or deepened such that the face of the footing at the level of the bottom is at least 8 feet from the face of slope at that level. Reinforcing in footings should consist of at least one #4 steel bar placed continuously in the top and bottom of continuous footings regardless of structural requirements. Reinforcing for isolated footings is dictated by the structural requirements. These recommendations are based upon on the soil type encountered and do not take into consideration the proposed bearing load. Footings deeper than 24 inches should have an additional #4 steel bar for each additional foot of depth. The onsite soils encountered during the site inspection should not be used to backfill the retaining wall. The backfill material should be SE30 sand or better. The wall should not be backfilled until the masonry has reached an adequate strength per the structural design engineers' design, 28 days after the pour or upon approval by the special inspector. Based on a review of the grading plans Carlsbad Trract No 89-18, Lot 32, in our professional opinion, it does not appear that the proposed temporary cuts will undermine the improvements on the neighboring property or of the stability of the slope. The temporary cuts should comply with OSHA standards; however, we do not know the means and methods of the contractor so we cannot give recommendations or Britt Styr & Allen Chalepas File No. 11 48A4-19 November 6,2019 the possible need for shoring. If shoring is required, the engineer of record should be contacted. The engineered fill slope along the northeasterly property side is approximately 20+/- feet high. This site demonstrates that inactions of 2:1 (H:V) or flatter. No visual evidence of slope disturbance was noted at the time of our inspection of the site. Based on our experience with similar conditions, the slope, which is comprised of landscaped, dense, clays, will demonstrate a minimum factor of safety against deep seated failures in excess 1.5. If shoring is required, OSHA standards should be used for Type A soil. All benched excavations 20 feet or less in depth shall have a maximum allowable slope of 3/4 to 1 and maximum bench dimensions as follows: A 1 20' M".3/4 SIMPLE BENCH It should be noted that the contractor is solely responsible for designing and constructing stable, temporary excavations and may need to shore, slope, or bench the sides of trench excavations as required to maintain the stability of the excavation sides. The contractor's "competent person", as defined in the OSHA Construction Standards for Excavations, 29 CFR,, Part 1926, should evaluate the soil exposed in the excavations as part of the contractor's safety process. Temporary cut slopes should be constructed in accordance with the recommendations presented in this section. In no other case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations. If a Concrete Slab-On-Grade, SOG is proposed, it should be designed by the project's structural engineer based on anticipated loading conditions. We recommend that conventional reinforced concrete SOG for this project be founded on 6 inches of Class II Virgin Aggregate Base (with approximately 2% +/- over optimum moisture content and 90% compaction, relative to the lab maximum dry density, ASTM D 1557), overlying a 12 inch thick zone of adequately placed and compacted structural fill. We recommend that a moisture barrier be provided by a 5 Britt Styr & Allen Chalepas File No. 1148A4-19 November 6, 2019 membrane, visqueen 10 culls in minimum thickness or equivalent, be placed at top of well compacted Class II Aggregate Base, then covered with 2 inches of moist clean sand having a minimum sand equivalent of 30 when tested in accordance with the American Society of Testing and Materials test method 'ASTM D1555 or as an alternative the updated AC! standard recommends that a moisture barrier of 15 mils in minimum thickness or equivalent, be placed at top of well compacted Class II Aggregate Base without the 2 inches of sand between the moisture barrier and the concrete. Floor slabs, as a minimum, should be 5 inches thick with #4 reinforcing steel at 16" on-center each way. Reinforcement should be placed at mid-height of the slab. The final slab thickness and reinforcement should be determined by the structural design engineer. We recommended concrete mix should use Type 5 cement, water cement ratio 0.4, concrete compressive strength of 4500psi. Concrete curing method can be blanket cover, spray retarding compound or spraying water regularly. Control joints should be provided in accordance with the recommendations of the structural design engineer. Resistance to horizontal movement may be provided by allowable soil passive pressure and/or coefficient of friction of concrete to soil. The allowable passive pressure may be assumed to be 250 psf at the surface and increasing at the rate of 150 psf per foot of depth. These pressures assume a frictionless vertical element, no surcharge and level adjacent grade. If these assumptions are incorrect, we should be contacted for values that reflect the true conditions. The values are for static conditions and may be increased 1/3 for wind and/or seismic loading. The coefficient of friction of concrete to soil may be safely assumed to be 0.3. Active pressures for the design of unrestrained, cantilevered, individually supported retaining walls, capable of slight movement away from load may be considered to be equivalent to the pressures developed by a fluid with a density of 45 pcf. This value assumes a vertical, smooth wall and level drained backfill. We should be contacted for new pressures if these assumptions are incorrect. Restrained walls, incapable of movement away from load without damage such as basement walls, should be designed for the additional equivalent fluid of 36 pcf applied triangularly for cohesionless type soils and trapezoidally for cohesive type soils. If the back fill is 2:1 slope behind the top of the wall, the wall should be designed as the additional wall height for the actual wall height divided by 2. e.g.: If the actual retaining wall is 6 feet from the top of footing to the top of the wall, then the wall height design load should be 6 feet plus 672 = 3 feet. The wall should be designed for 9 feet in height. Britt Styr & Allen Chalepas File No. 1148A4-19 November 6, 2019 The above design values and foundation design assume that the retaining walls are located in soils similar to those we tested during our site inspection. SEISMIC LOADING FOR RETAINING WALLS The seismic event induced dynamic load should be added to the lateral static pressures on basement, foundation and retaining walls for projects located in seismic design categories D, E or F. The following is the calculation for the dynamic load, which should be applied in addition to the static loads. References: USGS and IBC 2012/2016 Site Address: 3559 Corte Esperanza, Carlsbad Site Soil Classification: Site Class "D" S= 1.029g S= 1.120g Sth=0.747g Si = 0.398 g Smi = 0.639 g SdI = 0.426 g Kh =Peak Ground Acceleration= Sds 12.5 = 0.747 12.5 = 0.30 BackFill Density (Assumed 90% compaction) = 109.5 * (0.90) = 98.6 PCF H =The height of the level backfill behind the wall in FT Dynamic Load, for Yielding Wall= (.375) (0.30) (98.6 PCF) (H) = 11.1 lbs/ft (H2) Dynamic Load, for Non-Yielding Wall= (0.30) (98.6 PCF) (H2) = 29.6 lbs/ft (H2) The resultant dynamic load acts at a height of 0.6H above the base of the wall. The dynamic load is represented as an inverted triangular pressure distribution. These lateral earth pressures assume the walls are totally drained with no water behind them and assume there is no. surcharge applied. If there is any surcharge applied, it should be considered accordingly. 7 I 14- PO-01 -- Britt Styr & Allen Chalepas File No. 1148A4-19 November 6, 2019 See Figure below: FINISH GRADE DNDITICN Th £QUI VALENT FLUID PRESSURE (pft) fFORCE PER UNIT WiDTH OF WALL (11am) 10.3 ti Pa FINISH GRADE OP4DrnON UUM EQUIVALDIT FWDPREUR.E(pO) I Th FORCE PER UNIT WIDTH Of WALl. (fl) 27.5 W I. ASSUMES NO HYDROSTATIC BUILDUP BEHIND ThE RETAINING WALLS. 2.UISINFEET. 3. ASSUMEI LEVEL GRANULAR BACKFILL COMPACTED TO MINIMUM 90 PERCENT AND WIThIN 2 PERCENT OF OPTIMUM. & 5tIRCflMCE LOADS HAVE NOT BEEN INCLUDED. RETAINING WALL DRAINAGE For the restraining walls, the waterproofing: BG 2000 by Multicoat Corporation, being a water base coating, follows the manufacture for their recommendation. Place coating on top of footing and up on the inside of cmu wall to the top below the proposed slab (or equal). All wall drains shall be of 4 inch slotted drain pipe by (SDR-35-4") with a sock coverage throughout. The pipe shall have a minimum of 1 percent fall. Place Tencate geosynthectics- mirafl N-140, nonwoven (or equal) in a burrito wrap around the % inch washed crushed rock. The minimum thickness of crushed rock around the pipe is 4 inches on all sides. The contractor shall vibrate every 2 feet of lift to interlock the rock. For the retaining wall, the contractor can either follow the recommendations above or install a slotted pipe design or every six feet have a block turned on its side at 6-foot intervals and place half-inch galvanize wire between two layers of Tencate geosynthectics-mirafi N-140, nonwoven with 3/4 inch crushed rock behind for the full width and length of the block. All pipes shall have the labels up and glued and inspected prior to backfilling. F;] Britt Styr & Allen Chalepas File No. 11 48A4-19 November 6, 2019 SURFACE DRAINAGE It is with the understanding that no surface drainage system ties together with the retaining wall drainage system. The minimum slope for the surface drainage system shall be 2 percent fall and for self cleaning slope shall be 3 percent fall. When you go below 2 percent fall slope than you will need to increase the pipe size one size larger and if you go below 1 percent fall than the pipe size will be the minimum of 6 inch pipe. Connecting catch basins, down spots, landscape area drains to the main drainage system tie into the pipe using street ells or large sweeps. This will permit the use of snakes, and cameras for maintaining the drainage lines. Contractor shall place a clean out at the property line on all drainage pipes prior to discharge. The design of all drainage systems shall be shown and labeled/identified on the plan. All drainage pipes shall have either a headwall or projecting out from a retaining wall, face of curb, and be shown as a detail on the plans if a discharge at grade. All pipes shall have the labels up and glued and inspected prior to backfiuing. SITE EROSION CONTROL During the construction, surface water should be controlled via berms, gravel bags and/or sandbags, silt fence, straw wattles, siltation basins, while maintaining positive surface grades or other methods to avoid damage to the finish work or adjoining properties. All site entrances and exits must have coarse gravel or steel shaker plates to minimize offsite sediment tracking. Best management Practices (BMP's) must be used to protect storm drains and minimize pollution. The contractor should take measures to prevent erosion of graded areas until such time as permanent drainage and erosion control measures have been installed. After completion of grading, all excavated surfaces should exhibit positive drainage and eliminate areas where water might pond. SITE AND SURFACE DRAINAGE Drainage at the site should be directed away from foundations, collected and tight lined to appropriate discharge points. 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 towards the foundation. Landscaping requiring a heavy irrigation schedule should not be planted adjacent to foundations or paved areas. The type of drainage issues found within Britt Styr & Allen Chalepas File No. 1148A4-19 November 6, 2019 the project and materials specified and used should be determined by the Engineer of Record. GROUNDWATER AND SURFACE WATERS There was no indication of a near-surface groundwater table within our exploratory trench or perched groundwater. Although groundwater is not expected to be a significant constraint to the proposed development, our experience indicates that near-surface groundwater conditions can develop in areas where no such groundwater conditions previously existed, especially in areas where a substantial increase in surface water infiltration results from landscape irrigation or unusually heavy precipitation. It is anticipated that site development will include appropriate drainage provisions for control and discharge of surface water runoff. The type of drainage issues found within the project and materials specified and used should be determined by the Civil Engineer. The type of plants and soil specified along with proper irrigation used should be determined by the Landscape Architect. The following grading specifications should be utilized. RECOMMENDED GRADING SPECIFICATIONS For Proposed Residential Building Site 3559 & 3561 Corte Esperanza City of Carlsbad GENERAL: Soil Testers and 'Engineer' are synonymous hereinafter and shall be employed to inspect and test earthwork in accordance with these specifications, the accepted plans, and the requirements of any jurisdictive governmental agencies. They are to be allowed adequate access so that the inspections and tests may be performed. The. Engineer shall be apprised of schedules and any unforeseen soil conditions. Substandard conditions or workmanship, inadequate compaction, adverse weather, or deviation from the lines and grades shown on the plans, etc., shall be cause for the engineer to either stop construction until the conditions are corrected or recommend rejection of the work. Refusal to comply with these specifications or the recommendations and/or interpretations of the engineer will be cause for the engineer and/or his representative to immediately terminate his services. Deviations from the recommendations of the Soil Report, from the plans, or from these Specifications must be approved in writing by the owner and the contractor and endorsed by the engineer. 10 Britt Styr & Allen Chalepas SOIL TEST METHODS: Maximum Density & Opt Moisture Density of Soil In-Place Soil Expansion Shear Strength Gradation & Grain Size Capillary Moisture Tension Organic Content File No. 1148A4-19 November 6, 2019 --ASTM DI5S7-70 -- ASTM D1556, D2922 and D3017 -- UBC STANDARD 29-2 - ASTM D3080-72 -- ASTM D1140-71 - ASTM D2325-68 -- % Weight loss after heating for 24 hours at 300° F and after deducting soil moisture. LIMiTING SOIL CONDITIONS: Minimum Compaction 901/c for 'disturbed soils. (Existing fill, newly placed fill, plowed ground, etc.) 84% for natural, undisturbed soils. 95% for pavement subgrade within 2' of finish grade and pavement base course. Expansive Soils Expansion index exceeding 20 Insufficient fines Less than 40% passing the #4 sieve. Oversized Particles Rocks over 10" in diameter. PREPARATION OF AREAS TO RECEIVE FILL: Brush, trash, debris and detrimental soils shall be cleared from the areas to receive fill. Detrimental soils shall be removed to firm competent soil. Slopes exceeding 20% should be stepped uphill with benches 10' or greater in width. Scarify area to receive fill to 6" depth and compact. FILL MATERIAL shall not contain insufficient fines, oversized particles, or excessive organics. On-site disposition of oversized rock or expansive soils is to be at the written direction of the Engineer. Select fill shall be as specified by the engineer. All fills shall be compacted and tested. SUBDRAINS shall be installed if required by and as directed by and detailed by the engineer and shall be left operable and unobstructed. They shall consist of 3" plastic perforated pipe set in a minimum cover of 4" of filter rock in a 'vee' ditch to intercept and drain free ground from the mass fills. Perforated pipe shall be schedule 40, Poly-Vinyl-Chloride or Acrylonitrile Butadienne Styrene plastic. Rock filter material shall conform to the following gradation: Sieve size: 3/4" #4 #30 #200 %Passing: 90-100 25-50 5-20 0-7 Subdrains shall be set at a minimum gradient of 0.2% to drain by gravity and shall be tested by dye flushing before acceptance. Drains found inoperable shall be excavated and replaced. 11 Britt Styr &. Allen Chalepas File No. 1148A4-19 November 6, 2019 CAPPING EXPANSIVE SOILS: If capping expansive soils with non-expansive soil to mitigate the expansive potential is used, the cap should be compacted, non-expansive, select soil placed for a minimum thickness 3' over the expansive soil and for a minimum distance of 8' beyond the exterior perimeter of the structure. Special precautions should be taken to ensure that the non-expansive soil remains uncontaminated and the minimum thickness and dimensions around the structure are maintained. The expansive soils underlying the cap of non-expansive cap should be pre-saturated to a depth of 3' to obtain a degree saturation exceeding 90% before any construction supported by the compacted cap. The non-expansive soil comprising the cap should conform to the following: Minimum Compaction 90% Maximum Expansion Index 30 Minimum Angle of Internal Friction 33 Deg Cohesion Intercept 100 psf UNFORESEEN CONDITIONS: Soil Testers assume no responsibility for conditions, which differ from those, described in the applicable current reports and documents for this property. Upon termination of the engineer's services for any reason, his fees up to the time of termination become due and payable. If it is necessary for the engineer to issue an unfavorable report concerning the work that he has been hired to test and inspect, the engineer shall not be held liable for any damages that might result from his 'unfavorable report'. If we can be of any further assistance, please do not hesitate to contact our office. This opportunity to be of service is sincerely appreciated. Plates I through VIII and reference page are parts of this report. Respectfully submitted, e& YFESSIO& Chin C. Chen, RPE C34442 CCC/nilj O C 03"42 J \xp OF C 12 Britt Styr & Allen Chalepas File No. 1148A4-19 November 6, 2019 Plate No. I EXPLORATION NUMBER 1 Date Logged: 07/01/19 Equipment Used: Hand dug Date Reported: 08/08/19 Groundwater: Not Encountered Depth Unified Classifications Soil Descriotion Soil Tvne o to I' SC - Dark brown, moist, loose, SILTY CLAYEY SANDS with roots and organic materials (Landscape Fill) 1 to 4' SC Layered grey to tan, moist, soft, SILTY SANDY CLAYS with roots (Fill) 4 to 5' SC Grey, moist, soft, SILTY SANDY CLAYS 1 L with clay (Fill) bottom of excavation ____ Britt Styr & Allen Chalepas File No. 1148A4-19 November 6, 2019 Plate II LABORATORY TEST RESULTS The maximum dry densities and optimum moisture contents of the fill materials as determined by the A.S.T.M., D1557-78, Method A, which uses 25 blows of a 10 pound rammer falling from a height of 18 inches on each of 5 layers in a 4 inch diameter 1/30 cubic foot compaction cylinder, are presented as follows: Maximum Optimum Dry Density Moisture Soil Type lb./cu.ft. Content dry wt. 1 Grey, silty sandy clay 109.5 19.2 EXPANSION INDEX TESTS (ASTM D4829) Initial Saturated Initial Dry Moisture Moisture Density Expansion Content % Content% (PCF) Index Location 12.8 25.6 97.8 133 Il @4" DIRECT SHEAR TEST (ASTM D6528) Friction Sample Depth Cohesion, Angle (0 Soil Description Location In feet c (psf) (degrees) Type Sandy Clay Ti 3' 318 20 SC ~J. o7Ij L1 I PRO POS ED C IRCui.,.g EXPLORATION TRENCH "NO CAL.E" LOCATION OF EXPLORATION TRENCHES PL4r&Id. I II99AL4I 0I I I I 11421 Woodside Ave., Suite C Santee, California 92071 (619) 562-0500 PLATE' 4/ PROpOSED \. CIRCuL2 I \ VRVEV4 / I'ROVUSED / AR&.G E6N '. 4pproasirno4 Loe4iavi of Geo(ojk i4pproimA7'e £oca.*osl of J4sL ,#ycz^dlve P,11 J1i'e AcY $0 - - - - ft ppro%lm £.Oca+iO#I 0 7 #abLii4y Pi U. 5ubdroiai (so) JOB NO. ____ 0 LOCATION OF I I 14 A '- — 19 sr1qJL/71 ,F/zL JLoPE mo BY g 1171,011A TITIJ KEY ANO JLJ8PRP/AJ DATE - I • ,v'r ,z [ SPECIFICATION FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. STANDARD SIEVE SIZE % PASSING 100 3I4 90-100 3/8w 35-100 No.4 35-60 No. 30 10-30 No. 200 2-9 SAND EQUIVALENT < 30 PLATE VII SOIL BACKFIU., COMPACTED TO 90 PERCENT RELATIVE COMPACTION* :5SE3OSOIL 2:1 SLOPE RETAINING WALL.m.,.. BACK CUT 6'MIN. I-i2." FILTER FABRIC ENVELOPE WALL WATERPROOFING .0 IERLA! (MIRAFI 140N OR APPROVED PER ARCHITECT'S . .. -- EQUIVALENT) SPECIFICATIONS .c c.. uuur BACKFILL 501L 3/4CLEANGRAVEL' : :&• FINISH GRADE t \ \ .• . •. 4(MIN.) DIAMETER PERFORATED \ \ •: PVC PIPE (SDR-35 OR EQUIVALENT) WITH PERFORATIONS ORIENTED - oço -- DOWN AS DEPICTED MINIMUM 1 PERCENTGRADIENTTO - COMPACTED FILL t 8 MIF J j0 -- SUITABLE OUTLET ------ -'- - WALL FOOTING 3M1N. COMPETENT BEDROCK OR MATERIAL AS EVALUATED BYTHE GEOTECHNICAL CONSULTANT *BASED ON ASTM D1557 IF CALTRANS CLASS 2 PERMEABLE MATERIAL (SEE GRADATION TO LEFT) IS USED IN PLACE OF 3/40 GRAVEL FILTER FABRIC MAY BE DELETED. CALTRANS CLASS 2 PERMEABLE MATERIAL SHOULD BE COMPACTED 1090 PERCENT RELATIVE COMPACTION NOTE: COMPOSITE DRAINAGE PRODUCTS SUCH AS MIRADRAIN OR i-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR CLASS 2, INSTALLATION SHOULD BE PERFORMED IN ACCORDANCE WITH MANUFACTURER'S SPECIFICATIONS AND APPROVED BYTHE GEOTECHNICAL CONSULTANT NO SCALE H RETAINING WALL DRAINAGE DETAIL P.O. BOX 1195 LAKESIDE, CA 920401 Britt Styr & Alien Chalepas File No. 1148A4-19 November 6, 2019 References: Reference: Tan, S.S., 1986, Landslide Hazards in the Rancho Santa Fe Quadrangle, San DIego County, California Landslide Hazard Identification Map No. 6, OFR 86-15 - LA Leighton and Associates, Inc. Final As-Graded Report of Rough Grading, The Ranch, Phase I, Lots 1 through 40 and 129 through 131, Carlsbad Tract No. 89-18, Carlsbad California Dated June 19, 1996, Project No. 4940567-003 "As Built" Grading Plan Unit One, Sheet 13 Carlsbad Tract No. 89-18