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1994-4274 CN/G Street Address 3/6 4 5 Category Serial # c>L �{ , Name Description Plan ck. # Year recdescv -THE INEIRNG IGNGROUP GEOTECHNICAL AND STRUCTURAL CONSULTANTS FOR RESIDENTIAL AND LIGHT COMMERCIAL CONSTRUCTION DRAINAGE CALCULATIONS RICHARDS RESIDENCE APN 260 -29-14 CITY OF ENCINITAS, CA - Q�OEESSE� � z APR 12 1995 ,�,�w � y 5 ENG,INjEEt?iN' ' �l,�'F�`� No. GI "�Y OF Eta ' IXP. r 475 CARMEL STREET • SAN MARCOS, CA • 92069 • (619) 752 -7010 • FAX (619) 752 -7092 THE NORTH COUNTY BY: SN DATE: X-0- ENGINEERING DESIGN GROUP Page No: 1 PROJECT: RICHARDS RESIDENCE, APN 260- 29-14. REFERENCE: PLAN FILE NO: WATERSHED LESS THAN .5 SQUARE MILE USE RATIONAL METHOD Q = CIA C =.65 1100 = 5 IN /HR (SEE ATTACHED PAGES) A = .25 (APPROX) Q, -- = (,,651(51(.25) = .81 CF /S SAY 1 CBS * SEE ATTACHED COMPUTER ANALYSIS FOR PIPE SIZING AND ASSOCIATED ANALYSIS. PER ATTACHED COMPUTER ANALYSIS, USE 6 INCH DIAMETER SCHEDULE 40 OR SDR 35 PIPE LAID AT A MINIMUM 2% SLOPE FOR ALL YARD AND DRIVEWAY DRAINS THE OUTLETS OF ALL DRAIN SYSTEMS TO HAVE RIP RAP (SEE DETAIL D -2) AT ALL PIPE OUTLETS. JOB NO. 475 CARMEL STREET . SAN MARCOS • CA • 92069 • (619)752 -7010 • (619)752 - 7092 -FAX Circular Channel Analysis & Design Solved with Manning's Equation Open Channel - Uniform flow Worksheet Name: RICHARDS Description: RICHARDS DRAINAGE ANALYSIS Solve For Full Flow Diameter Given Constant Data; Mannings n......... 0.011 Variable Input Data Minimum Maximum Increment By Slope 0.0200 0.0500 0.0100 Discharge 1.00 2.00 1.00 COMPUTED VARIABLE VARIABLE COMPUTED COMPUTED COMPUTED Diameter Channel Mannings Discharge Depth Velocity Capacity ft Slope 'n' cfs ft fps Full ft /ft cfs 0.51 0.0200 0.011 1.00 0.51 4.85 1.00 0.47 0.0300 0.011 1.00 0.47 5.65 1.00 0.45 0.0400 0.011 1.00 0.45 6.29 1.00 0.43 0.0500 0.011 1.00 0.43 6.84 1.00 0.66 0.0200 0.011 2.00 0.66 5.77 2.00 0.62 0.0300 0.011 2.00 0.62 6.72 2.00 0.58 0.0400 0.011 2.00 0.58 7.49 2.00 0.56 0.0500 0.011 2.00 0.56 8.14 2.00 1 1 EIT ..i. 1 t : 1 ' ' I NI CD T 0 cl ell w r N N I�1 t+S•P�a tA1p101 � � t�T • • • to O t71 O tsar O vrOv/Ow0 '" x (sayL} UO vz �dj,�a id anoH -g » -Vkb� w ro o r tD O O �_ e�+ �-► ate+ C —t 7V - tl► 'n rn 4 at _ w o- oft � 0 O a am 40 z CD 0 R -+• C to S N C N ai4 et t a+ � e+ e+ D CO C 3 O G • CL d O/ O -+ n S -2 =r CM Up • IL 'M ID :s e+ � O -�� 9 n O l u ID _n o -•. o ar to 0. to o - Ch •• c 'Q N C •• IT C+ S CD co e+= O J M er Or 'O �..a. • ID /D S •S n n =r _% Cf lc► .r -. tla O 2. _. •r . 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LIN cp — — , L! r CD cp ej ca Cr ca lcm cm uv tN � t , a a .. i Ab CD .: cm 1 HE 1 ESIGN GROUP 1 T OTECHNICAL AND STRUCTURAL CONSULTANTS FOR RESIDENTIAL AND LIGHT COMMERCIAL CONSTRUCTION 1 GEOTECHNICAL INVESTIGATION AND FOUNDATION RECOMMENDATIONS, PROPOSED SINGLE FAMILY RESIDENCE, TO BE LOCATED ON A.P.N. 260- 292.14 1 CITY OF ENCINITAS, CALIFORNIA 1 1 Project No. 95928 -1 1 April 18, 1995 1 APR 18 1995 ES 1Pf;' c`E V!CE- 1 PREPARED FOR: CrTY of= E, ;N ,NI?'AS, Larry Richards j 1 L.D. RICHARDS COMPANY 1315 Crest Drive i Encinitas, CA 92024 1 i { 475 CARMEL STREET • SAN MARCOS, CA • 92069 • (619) 752 -7010 • FAX (619) 752 -7092 TABLE OF CONTENTS ' SCOPE ................................. ............................... 2 ' SITE AND PROJECT DESCRIPTION ............ ............................... 2 GEOLOGIC HAZARDS AND SEISMICITY ......... ............................... 2 GROUNDWATER ......................... ............................... 3 CONCLUSIONS AND RECOMMENDATIONS GENERAL......................... ............................... 4 ' EARTHWORK ........................ ............................... 4 FOUNDATIONS ....................... ............................... 5 ' CONCRETE SLABS ON GRADE ........... ............................... 6 RETAINING WALLS .................... ............................... 7 ' SURFACE DRAINAGE .................. ............................... 8 CONSTRUCTION OBSERVATION AND TESTING .............................. 8 MISCELLANEOUS .......................................................... 8 ATTACHMENTS ' Site Vicinity Map ......................... .........................Figure No. 1 Site Location Map .................. ............................... Figure No. 2 ' Site Plan ......................... ............................... Figure No. 3 .General Earthwork and Grading Specifications ............................. Appendix -A- Job No. 95928 -1 Page No. 1 1 ICOPE 1 This report gives the results of our geotechnical investigation for the proposed single family residence to be on APN 260- 292 -14, in the City of Encinitas, California. Please see Figure No. 1 1, "Site Vicinity Map ", and Figure No. 2, "Site Location Map°. The scope of our work, conducted on -site to date, has included a visual reconnaissance of the property and neighboring properties, consultations with the project contractor, preparation of a grading and drainage plan, and preparation of this report presenting our findings, conclusions, and recommendations. SITE AND PROJECT DESCRIPTION The subject property consists of a irregularly shaped lot located on the west side of Oxford Avenue, in the City of Encinitas, California. The site is bordered to the north, south, and west ' by similarly developed residential properties and to the east by Oxford Avenue. Currently the site is vacant of structures. 1 The overall topography of the site area consists of gently to moderately rolling coastal terrain. The lot itself slopes gently to moderately to the west. Based on our conversations with the property owner and review of the grading and drainage plan, we understand the proposed site ■ improvement will consist of a new one and two story single family residence. Also, we ■ understand the construction will consist of conventional wood framing with perimeter stemwalls and structural wood floors. In addition, a masonry block or keystone retaining wall system, six 1 feet in maximum height, is also planned along the western portion of the site. ' GEOLOGIC HAZARDS AND SEISMICITY A review of pertinent published geologic maps, suggests that no geologic hazards such as special studies zone faults, potential landslides, or areas of suspected soil liquefaction exist within the project boundaries. Based on this information, it appears that no active or potentially active ' fault exists at or in the immediate vicinity (250 ft.) of the site, and none were observed during our investigation. It is our opinion that the site could be subjected to moderate to severe ground shaking in the event of a major earthquake along any of the faults in the Southern California 1 region; however, the seismic risk at this site is not significantly greater than that of the surrounding developed area. Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earthquakes. 1 Research and historical data indicate that loose, granular soils underlain by a near-surfacea ground water table are most susceptible to liquefaction, while the stability of most silty clays and 1 clays is not adversely affected by vibratory motion. Because of the dense nature of the formational materials underlying the site and the absence of a near surface groundwater table, the potential for liquefaction or seismically- induced dynamic settlement at the site is considered low. The effects of seismic shaking can be reduced by adhering to the most recent edition of Job No. 95928-1 Page No. 2 I i the Uniform Building Code and current design parameters of the Structural Engineers Association ' of California. GROUND WATER Ground water is not anticipated to be a significant concern to the project provided the ' recommendations of this report are followed. ' Job No. 95928 -1 Page No. 3 CONCLUSIONS AND RECOMMENDATIONS G ENERAL In eneral, it is our opinion the proposed site improvement, as described herein, is 9 P P P P feasible from a geotechnical standpoint, provided the recommendations of this report ' and generally accepted construction practices are followed. EARTHWORK Site grading may be conducted in accordance with the following recommendations and Appendix A of this report. Site Prey Prior to starting excavations, the site should be cleared of vegetation, debris and other deleterious materials. Removed materials not suitable for backfill should be disposed ' of off site. Approximately three tree stumps were observer within the limits of proposed grading. Removal of trees should include their root systems, and during grading the ' associated excavations backfilled as outlined below. ExcavationlRemovals ' In areas where structural improvements are to be founded on fill, topsoils should be removed to competent formation materials and recompacted to a minimum of 90 percent of the maximum dry density (based on ASTM D1557 -78). Removals should be accomplished a minimum of 5 feet (measured laterally) beyond proposed settlement sensitive improvements. Removal depths are anticipated up to ' approximately 3.0 feet. Actual depths of removal should be visually evaluated during excavation by a representative of our firm and may be locally deeper based on actual field conditions. ' r than To satisfy OHSA requirements, excavations deeps 5 feet should be shored or laid back to 1:1 (horizontal to vertical). Excavations should be periodically monitored by the project contractor for sloughing or caving. If excessive sloughing or caving is observed, excavations should be filled immediately and our office notified. Fills The onsite soils are generally suitable for reuse as compacted fill provided they are ' free of organic materials and debris. All areas to receive fill and /or other surface Job No. 95928 -1 Page No. 4 improvements should be scarified to a depth of 6 inches, brought to approximately ' 2 percent above optimum moisture condition, and recompacted to at least 90 percent relative compaction (based on ASTM D1557 -78). The optimum lift thickness required to produce a uniformly compacted fill will depend on the type and size of compaction equipment used. In general, fill should be placed in uniform lifts not exceeding 6 inches in thickness. Material greater than 4 inches in maximum dimension should not be utilized in fills. Fill soils should be placed at least 2 percent above optimum moisture content and compacted to a minimum of 90 percent relative compaction (based on ASTM D1557 -78). Placement and compaction of fill should be performed under the observation and testing of our office. FOUNDATIONS ' In deriving new foundation recommendations for this site, the subsoil conditions and the proposed new construction were evaluated. We anticipate that the new foundation ' system for the structure will utilize perimeter stemwall footings with structural wood floors. Foundation systems may be designed as follows: ' xt ri r footings should be founded within competent com 1. All new interior and e e o g p formational materials or founded on properly compacted fill materials (see Earthwork). ' 2. Footings bearing in formational materials or properly compacted fill may be designed based on a maximum allowable soils pressure of 2,000 psf. ' 3. Bearing values may be increased by 33% when considering wind, seismic, or other short duration loadings. 4. All loose soil found at the base of footings, when the excavation is opened, shall be removed and extended to firm, undisturbed soils. ' 5. The following parameters should be used as a minimum, for designing footing width and depth below lowest adjacent grade (low expansive soil): Depth Below Lowest Adjacent Floors Supported Width Grade 1 15 inches 18 inches 2 15 inches 18 inches 3 18 inches 24 inches ' Job No. 95928-1 Page No. 5 6. All footings should be reinforced with a minimum of two #4 bars at the top ' and two #4 bars at the bottom (3 inches above bottom of footing). For footings over 30 inches in depth, additional reinforcement, and possibly a stem wall system, will be necessary. This detail should be reviewed on a ' case by case basis by our office prior to construction. 7. All isolated spread footings should be designed utilizing the above given ' bearing values and footing depths, and be reinforced with a minimum of #4 bars at 12 inches o.c. in each direction (3 inches above bottom of footing). Isolated spread footings should have a minimum width of 24 inches. ' 8. For footings adjacent to slopes, a minimum 7 feet horizontal setback in formational material or properly compacted fill should be maintained. Setback measurement should be taken as the horizontal distance from the bottom of the footing to slope daylight. ' 9. All excavations should be performed in general accordance with the contents of this report, applicable codes, OSHA requirements and applicable city and /or county standards. CONCRETE SLABS ON GRADE Concrete slab on grade floors should be designed and constructed in accordance with the following design parameters. 1. Concrete slabs on grade should have a minimum thickness of 4 inches, and should be reinforced with #3 bars at 18 inches o.c., each way. 2. All required fills used to support slabs, should be placed in accordance with I the "Earthwork" section of this report and compacted to 90% Modified Proctor Density, ASTM D -1557. ' 3. A uniform layer of 4 inches (minimum) of clean sand is recommended under the slab in order to uniformly support the slab, help distribute loads to the soils beneath the slab, and act as a capillary break. In addition, a visqueen ' layer (6 mil) should be placed mid - height in the sand bed to act as a vapor barrier. ' 4. Adequate control joints (minimum of every 400 s.f., 1 inch vertical cut) should be installed to control the unavoidable cracking of concrete that takes place when undergoing its natural shrinkage during curing. The control joints should be well located to direct unavoidable slab cracking to Job No. 95928 -1 Page No. 6 I' i 1 areas that are desirable by the designer. 1 5. Brittle floor finishes placed directly on slab on grade floors may crack if concrete is not adequately cured prior to installing the finish or if there is 1 minor slab movement. To minimize potential damage to movement sensitive flooring, we recommend the use of slip sheeting techniques which allows for foundation and slab movement without transmitting this ' movement to the floor finishes. 1 RETAINING WALLS Based on our review of the project grading and drainage plans, retaining walls up to 1 approximately six feet in height are proposed as part of the improvement. Retaining walls may be constructed in accordance with the following recommendations and 1 design parameters: 1. Retaining wall footings should be designed in accordance with the allowable bearing criteria given in the "Foundations" section of this report. 1 2. Unrestrained cantilever retaining walls should be designed using an active 1 equivalent fluid pressure of 35 pcf. This assumes that granular, free draining material will be used for backfill, and that the backfill surface will be level. For sloping backfill, the following parameters may be utilized: 1 Condition 2:1 Slope 1.5:1 Slope Active 45 55 1 Any 9 other surcharge loadings shall be analyzed in addition to the above values. 1 3. If retaining walls are restrained from movement, they should be designed for an additional uniform soil pressure of 7XH psf, where H is the height of 1 the wall in feet. 4. Passive soil resistance may be calculated using an equivalent fluid pressure 1 of 250 pcf. This value assumes that the soil being utilized to resist passive pressures, extends horizontally 2.5 times the height of the passive pressure wedge of the soil. Where the horizontal distance of the available passive 1 pressure wedge is less than 2.5 times the height of the soil, the passive pressure value must be reduced by the percent reduction in available 1 horizontal length. 1 Job No. 95928 -1 Page No. 7 5. A coefficient of friction of .35 between the soil and concrete footings may ' be utilized to resist lateral loads in addition to the passive earth pressures above. ' 6. Retaining walls should be braced and monitored during compaction. If this cannot be accomplished, the compactive effort should be included as a surcharge load when designing the wall. 7. All walls shall be provided with adequate back drainage to relieve ' hydrostatic pressure (see Appendix A). All exterior site retaining walls shall have the strike mortar omitted in the lowest course to allow for drainage. ' 8. Retaining wall backfill should be placed and compacted in accordance with the "Earthwork" section of this report. ' SURFACE DRAINAGE ' Adequate surface drainage precautions at this site are imperative. Under no circumstances should water be allowed to pond against or adjacent to footings, foundation walls or retaining walls. The ground surface surrounding the building should be relatively impervious in nature, and slope to drain away from the building in all directions, with a minimum slope of 2% for a horizontal distance of 5 feet. Area drains or surface swales should then be provided to accommodate runoff and avoid ' any ponding of water. Roof gutters, downspouts and drains should be considered for the new structure. Surface and area drains should not be connected to any wall ' drainage or underdrain system. ' CONSTRUCTION OBSERVATION AND TESTING The following services should be conducted by our office prior /during construction. ' 1. Observation of bottom of removal prior to fill placement. 2. Observation of fill placement & associated compaction testing. 3. Observation of foundation excavations. ' MISCELLANEOUS It must be noted that no structure or slab should be expected to remain totally free ' of cracks and minor signs of cosmetic distress. The flexible nature of wood and steel structures allows them to respond to movements resulting from minor unavoidable settlement of fill or natural soils, the swelling of clay soils, or the motions induced from i' seismic activity. All of the above can induce movement that frequently results in cosmetic cracking of brittle wall surfaces, such as stucco or interior plaster or interior Job No. 95928 -1 Page No. 8 ' brittle slab finishes. Data for this report was derived from surface observations at the site, knowledge of ' local conditions, and a visual observation of the soils exposed in the exploratory test pits. The recommendations in this report are based on our experience in conjunction with the limited soils exposed at this site and neighboring sites. We believe that this ' information gives an acceptable degree of reliability for anticipating the behavior of the proposed structure; however, our recommendations are professional opinions and ' cannot control nature, nor can they assure the soils profiles beneath or adjacent to those observed; therefore, no warranties of the accuracy of these recommendations, beyond the limits of the obtained data, is herein expressed or implied. This report is ' based on the investigation at the described site and on the specific anticipated construction as stated herein. If either of these conditions is changed, the results would also most likely change. Man -made or natural changes in the conditions of a property can occur over a period of time. In addition, changes in requirements due to state of the art knowledge ' and /or legislation, are rapidly occurring. As a result, the findings of this report may become invalid due to these changes. Therefore, this report for the specific site, is subject to review and not considered valid after a period of one year, or if conditions ' as stated above are altered. It is the responsibility of the owner or his representative to insure that the information ' in this report be incorporated into the plans and /or specifications and construction of the project. It is advisable that a contractor familiar with construction details typically used to deal with the local subsoil and seismic conditions, be retained to ' build the structure. If you have any questions regarding this report, or if we can be of further service, ' please do not hesitate to contact us. We hope the report provides you with necessary information to continue with the development of the project. t Very truly yours, THE NORTH C NTY ING DESIGN GROUP .._ Steven orris California RCE #47672 LU h1o. 47672 ' F C ' Job No. 95928 -1 Page No. 9 y� Ric J J •1 �- _f!! "_ 'u, do ..-yam � _� 1 . ` •� w �K; . M Z i omi _ rT J • I i i I 'va Y 17� jel- • �. , —�� � ...rev •- --,.- � • • t i - s •_ i ' m 9 O w i 1 APPENDIX A ' GENERAL EARTHWORK AND GRADING SPECIFICATIONS i 1.0 General Intent These specifications are presented as general procedures and recommendations for i grading and earthwork to be utilized in conjunction with the approved grading plans. These general earthwork and grading specifications are a part of the recommendations contained in the geotechnical report and shall be superseded by the 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 1 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 Testing i Prior to the commencement of radin a qualified g g, q ed geotechnical consultant should be employed for the purpose of observing earthwork procedures and testing the fills ' for conformance with the recommendations of the geotechnical report and these specifications. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes, at least 24 hours in ' advance, so that he may schedule his personnel accordingly. No grading operations should be performed without the knowledge of the geotechnical consultant. The i contractor shall not assume that the geotechnical consultant is aware of all grading operations. i 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 in the geotechnical report, and the approved grading plans not withstanding the testing and observation of the geotechnical consultant. If, in the opinion of the consultant, unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction, 1 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. Maximum dry density tests used to evaluate the degree of compaction should be performed in general accordance with the latest version of the American Society for i Testing and Materials test method ASTM D1557. 1 A -,- ' APPENDIX A Cont'd.) ' Pr eparation f Areas t Filled 3.0 o eas o e ll ' in Sufficient brush vegetation, 3.1 Clearing and Grubbin Suffi eg , 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. The geotechnical consultant should evaluate the extent of these removals depending on specific site conditions. In general, no more than 1 percent (by ' volume) of the fill material should consist of these materials and nesting of these materials should not be allowed. 3.2 Processing 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 day lumps or clods and until the working surface is reasonably uniform, flat, and free of uneven features which would inhibit uniform compaction. ' 3.3 v r x cav ion : Soft, dry, organic-rich, spongy, highly fractured, or otherwise e e g unsuitable ground, extendingto 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 quantities of materials overexcavated, a licensed land ' surveyor /civil engineer should be utilized. ' 3.4 Moisture Conditioning Overexc avated and processed soils should be watered, dried -back, blended, and /or mixed, as necessary to attain a uniform ' moisture content near optimum. ' 3.5 Recom aeon 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 or as otherwise recommended by the geotechnical consultant. I I' A -2- APPENDIX A (Cont'd.) ' 3.6 n hin : Where fills are to be placed on ground with slopes 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, at least 2 feet into competent material as evaluated by the geotechnical consultant. Other benches should be excavated 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. 3.7 Evaluation of Fill Areas All areas to receive fill, including processed areas, removal areas, and toe -of -fill benches, should be evaluated by the geotechnical consultant prior to fill placement. 4.0 Fill Material 4.1 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 too placement Soils of poor gradation, expansion, or strength characteristics should be placed as recommended by the geotechnical consultant or mixed with other soils to achieve satisfactory fill material. ' 4.2 Oversize: Oversize material, defined as rock or other irreducible material with a maximum dimension greater than 6 inches, should not be buried or placed in fills, unless the location, materials, and disposal methods are specifically recommended by the geotechnical consultant. Oversize P disposal operations P should be such that nesting of oversize material does not occur, and such that the oversize material is complete surrounded b compacted r IY y o densfied fill. Oversize material al sho i u d not be placed within 10 feet vertically of finish grade, within 2 feet of future utilities or underground construction, or within 15 feet horizontally f ' o slope faces, in accordance with the attached detail. A -3- } APPENDIX A (Cont'd.) ' 4.3 Import If importing of fill material is required for grading, the import material should meet the requirements of Section 4.1. Sufficient time should be given ' to allow the geotechnical consultant to observe (and test, if necessary) the proposed import materials. 5.0 Fill Placement and Compaction ' 1 : Fill material should be laced in areas prepared and previously 5. Fill Letts P P P P ly evaluated to receive fill, 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 throughout. soils should be watered dried -back blended 5.2 Moisture Condrttoninq Fill so s , and /or mixed, as necessary to attain a uniform moisture content near optimum. 5.3 Compaction 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 (unless otherwise specified). 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. 5.4 Fill Slopes Compacting of slopes should be accomplished, in addition to normal compacting procedures, by backrolling of 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 out to the slope face would be at least 90 percent. ' A -4- APPENDIX A (Cont'd.) 5.5 Compaction Testing Feld tests of the moisture content and degree of compaction of the fill soils should be performed at the consultant's discretion based on field conditions encountered. In general, the tests should be taken at approximate intervals of 2 feet in vertical rise and /or 1,000 cubic yards of compacted fill soils. In addition, on slope faces, as a guideline approximately one test should be taken for each 5,000 square feet of slope face and /or each 10 feet of vertical height of slope. 6.0 Subdrain Installation ' Subdrain systems, if recommended, should be installed in areas previously evaluated for suitability by the geotechnical consultant, to conform to the approximate alignment and details shown on the plans or herein. The subdrain location or ' materials should not be changed or modified unless recommended by the geotechnical consultant. The consultant, however, may recommend changes in subdrain line or grade depending on conditions encountered. All subdrains should be surveyed by a licensed land surveyor /civil engineer for line and grade after installation. Sufficient time shall be allowed for the survey, prior to commencement of filling over the subdrains. ' 7.0 Excavation Excavations and cut slopes should be evaluated by a representative of the ' geotechnical consultant (as necessary) during grading. If directed by the geotechnical consultant, further excavation, overexcavation, and refilling of cut areas and /or remedial grading of cut slopes (.e., stability fills or slope buttresses) may be ' recommended. 8.0 Qui ' y Determination For purposes of determining quantities of materials excavated during grading and /or ' determining the limits of overexcavation, a licensed land surveyor /civil engineer should be utilized. A -5- r THE 1 "'IGN GROUP WoTECHNICAL AND STRUCTURAL CONSULTANTS FOR RESIDENTIAL AND LIGHT COMMERCIAL CONSTRUCTION r r Date: June 20 , 1995 r To: Larry Richards 1 L.D. RICHARDS CO. 1315 Crest Drive Encinitas, CA. 92024 r Re: Richards Residence , Located at 1830 Oxford Avenue, Encinitas, CA. 1 Subject: Interim Compactio n Report for General Site Grading and Retaining Wall p 1 Backfill. Ref: * " Geotechnical Investigation and Foundation Recommendations, Proposed Single Family Residence, to be Located on A.P.N. 260- 292 -14, City of 1 ,Encinitas, California ", prepared by Engineering Design Group, dated April 27, 1995. 1 * "Grading and Drainage Plan Richards Residence, APN 260- 292 -14 City of Encinitas," prepared by North County Engineering Design Group, dated 1 April 13, 1995. 1 INTRODUCTION In accordance with your request and authorization, we have reviewed the referenced 1 geotechnical report, provided geotechnical observation and compaction testing services, during rough grading and retaining wall backfll operations at the subject property. This interim report consists of geotechnical observations and compaction test results through 6/12/95. Additional 1 fill placement will be required for proposed finish pad grades for garage and driveway subgrade, and backfilling of the stemwalls for the residential structure. 1 GRADING OPERATIONS 1 Page No: 1 1 Project No: 9592 8-4 475 CARMEL STREET - SAN MARCOS, CA - 92069 - (619) 7S2 -7010 - FAX (619) 752 -7092 1 was performed in general accordance with the recommendations of the referenced geotechnical report for the proposed improvement. Prior to the start of grading, areas ' improvement where stripped of vegetation and unsuitable material. Site grading generally consisted of the cutting of a keyway for the fill slope onsite, benching out of loose topsoils to competent formational material, undercutting of the building pad to 3+ feet below finish pad grade (5 ft. outside footprint where possible), and general fill placement & compaction to finish grade elevation. Relatively minor amounts of on -site soils were generally mixed with import material prior to placement as fill material. The bottom of keyways and pad undercuts were ' scarified to a depth of approximately 12 inches and moisture conditioned. Bottoms of removal were observed by an engineer from our firm prior to the placement of fill. Fill soils were placed under the full time observation and testing of our personnel. ' Soils 99 9 were aced during grading predominately derived from import sources, in addition to pad p undercuts and keyways. Based on experience with similar soil types, fill materials placed are ' generally non expansive in nature. During grading, fill soils were generally mixed, moisture conditioned, and compacted to a minimum of 90 percent of the maximum dry density (ASTM D1557 -78). Compaction was accomplished by tracking utilizing a CAT D6H, and water hose. ' retaining walls stem was conducted during the Backfill of the keystone y 9 eriod of 6/2/95 P through 6/9/95. Compaction was accomplished by a Bomag vibratory drum roller and water hose. Backfill material was placed under the part time observation and testing of our personnel. t SUBSURFACE CONDITIONS ' The subsoil conditions encountered within the subject area during site grading, are generally similar to those described in the referenced report for the site. FIELD AND LABORATORY TESTING ' The approximate locations of our field density tests are presented in Figure No. 1, "Field Density Test Location Map ". The results of the laboratory and field tests for the referenced site are presented in Table No. 1, "Laboratory and Field Test Results ". Field density tests were performed in accordance with ASTM D1556 -82 (Sand Cone Method). ' Our test results indicate that the fill placed, under our observation and testing, in the areas indicated in Figure No. 1, "Field Density Test Location Map ", have been compacted to at least 90 percent relative compaction, as determined by ASTM D1557 -78. The reported test results ' are representative of the soil conditions at the locations tested. Our observation and field density testing methods are in accordance with normally accepted procedures. The accuracy of the relative compaction values are subject to the precision limitations of the ASTM test Page No: 2 ' Project No: 95928 -4 r r methods. The accuracy of the maximum dry density determination (ASTM D1557 -78) is discussed in the 1985 Annual Book of ASTM Standards, Section 4, Volume 04.08, entitled, Soil r and Rock: Building Stones To date, ASTM has not reported on the accuracy of the field density test procedure (ASTM D1556 -82). Variations of relative compaction values should be expected, laterally and vertically, from the actual test locations. r SUMMARY AND RECOMMENDATIONS r In general, it is our opinion that the fill soils placed at the site at the locations tested, were compacted to a minimum of 90 percent relative compaction (based on ASTM D1557 -78). In r addition, the geotechnical conditions encountered during grading and excavation of the site, were found to be in general conformance with the conditions described in the geotechnical evaluation report for the site. r The following items should be noted: r 1) Compaction testing should be conducted on additional fills placed on the subject site. 2) Footing excavations should be observed by our representative prior to the placement r of reinforcement. r 3) Adequate drainage precautions at this site are imperative and will play an important role on the performance of the structure. Under no circumstances should water be allowed to pond against or adjacent to footings or retaining walls or to sheet flow over slopes. r The ground surface surrounding the building should be relatively impervious in nature, and slope to drain away from the building in all directions, with a minimum slope of 2% for a horizontal distance of 7 feet (where possible). Area drains or surface swales r should then be provided to accommodate runoff and avoid any ponding of water. Roof gutters, downspouts and drains should be considered on the new structure. Surface and area drains should not be connected to any wall drainage, french drain or r underdrain system (see attached Homeowners Maintenance Guidelines). 4) Adequate control joints (minimum of every 400 s.f., 1 inch vertical cut) should be r installed to control the unavoidable cracking of concrete that takes place when undergoing its natural shrinkage during curing. The control joints should be well located to direct unavoidable slab cracking to areas that are desirable by the designer. r 5) Brittle floor finishes placed directly on slab on grade floors may crack if concrete is not adequately cured prior to installing the finish or if there is minor slab movement. To ' minimize potential damage to movement sensitive flooring, we recommend the use of a slip sheet which allows for foundational slab movement, without transmitting this movement to the floor finishes. 1 Page No: 3 t Project No: 9592 8-4 1 ' minimize potential damage to movement sensitive flooring, we recommend the use of a slip sheet which allows for foundational slab movement, without transmitting this ' movement to the floor finishes. CONSTRUCTION OBSERVATION AND TESTING We recommend that any additional fill placement, including building pad and wall backfill, be ' observed by a representative of this office, so that construction is performed in accordance with the recommendations of this report and the referenced geotechnical report. We request a minimum 24 -hour notice prior to any observations, so that proper scheduling of our personnel can be made. If variations of site conditions are encountered during construction, this office may be recommendations or des Chan y should be notified, so that appropr es 9 9 implemented. t ni to be of p rofessional service to you in this matter. If you have We appreciate the opportunity p Y any questions regarding our report, please do not hesitate to contact this office. Very truly yours, ENGINEERI G GROUP Steven Norris ' California RCE #47672 ' Attachments: Table No. 1, "Laboratory and Field Test Results" Figure No. 1, "Field Density Test Location Map" Home Owners Guidelines ' OQ NOFESS /p I Np !� ' C.0 5 2z No. 47 M �x EXP OVIL �P F QF CALIFO� Page No: 4 ' Project No: 95928 -4 TABLE NO. 1 LABORATORY AND FIELD TEST RESULTS ' Laboratory Test Results SOIL TYPE MAXIMUM DENSITY (PCF) OPTIMUM MOISTURE U.S.C.S. CLASSIFICATION 1 Tan, SI.Clayey 122.8 9.5 SM ' Silty Sand ' Field Test Results TEST NO: DATE ELEVATION SOIL DRY DENSITY FIELD MOISTURE RELATIVE ' (FEET) TYPE (PCF) (PERCENT) COMPACTION 1 5/25/95 145 1 111.6 11 91 2 5/25/95 147 1 113.2 11 92 ' 3 5/25/95 149 1 112.3 10 91 4 5/25/95 151 1 112.7 11 92 t 5 5/26/95 153 1 114.3 11.5 93 6 5/26/95 154 1 116.2 9.5 95 7 5/30/95 155 1 116.2 10 95 8 5/30/95 157 1 112.9 11 92 ' 9 5/30/95 157.5 1 112.4 11 92 10 5/30/95 158 1 114.2 11 93 ' 11 6/2/95 148 1 117.2 10 96 12 6/2/95 150 1 117.0 10 95 ' 13 6/5/95 152 1 119.9 11 98 14 6/6/95 154 1 115.2 10 94 15 6/8/95 156 1 118.5 10 97 ' 16 6/8/95 157 1 115.8 10 94 17 6/12/95 *159 1 116.6 10 95 ' 18 6/12/95 *155 1 1 115.9 9 94 ' NOTE: MAXIMUM DENSITY /OPTIMUM MOISTURE CONTENT OF IMPORT MATERIAL PREPARED BY SOIL PACIFIC INC. 1 ' LEGEND 18 APPPROPRIATE LOCATION OF FIELD DENSITY TESTS 1 4 II III t 3 W a:Jr U ,us .� 5 . r ' ......' .. �1 6 ® ,.. \ W •� ' \ \ la r a ' NORTH NOT TO SCALE F7 Tim DIESM GEMP ' SITE VICINITY MAP JOB NO: 95928 -4 BY: KAR I FIGURE NO: 1 ' HOMEOWNERS MAINTENANCE GUIDELINES Residential homesites require periodic maintenance of irrigation and drainage systems to ' insure proper performance and overall retention of property value. Often, homeowners are not aware of the importance of these systems and allow them to deteriorate. ' During the construction phase of development, governing agencies require property developers to utilize specific methods of engineering and construction to protect the public interest. For instance, the developer may be required to grade the property in ' such a manner that rainwater will be drained away from the building pad, install brow ditches & terrace drains, and to plant slopes to minimize erosion. However, once the lot is purchased, it becomes the buyer's responsibility to maintain these safety features by ' observing a prudent program of lot care and maintenance. Failure to make regular inspection and perform necessary maintenance of drainage devices and sloping areas ' may cause severe financial loss. In addition to his /her own property damage, the property owner may be subject to civil liability for damage occurring to neighboring properties as a result of negligence. ' The following maintenance guidelines are provided for the protection of the homeowner's investment. A. All roof gutter and downspout systems, installed on the residence, should ' be tightlined to a suitable outlet away from the structure. Under no circumstances should water be allowed to pond onsite, particularly against the perimeter foundation system. ' B. Soils rades adjacent to the foundation of the structure should be sloped 9 1 to direct water away from the foundation and into a collective drainage ' system. Soil grades should slope at a minimum of 2% for a horizontal distance of 5 feet away from the structure. ' C. The irrigation of planter systems located immediately adjacent to the foundation should be strictly controlled to avoid over watering. Saturation ' of soils in these planters may result in soil settlement /expansion and associated distress. D. Care should be taken to ensure that slopes, terraces, berm, and proper lot drainage are not disturbed. ' E. In general, roof and yard runoff should be directed to either the street or storm drain by non - erosive devices such as sidewalks, drainage pipes, ground gutters, and driveways. Drainage systems should not be altered ' without expert consultation. 1 ' F. All drains should be kept clean and unclogged, including gutters and downspout's. Terrace drains or gunite ditches should be kept free of debris ' to allow proper drainage. During periods of heavy rain, the performance of the drainage systems should be inspected. Problems, such as gullying and ponding, if observed, should be corrected as soon as possible. t G. Any leakage from pools, waterlines, etc. or surface runoff bypassing drains should be repaired as soon as possible. ' H. Animal burrows should be eliminated since they may cause diversion of surface runoff, promote accelerated erosion, and even trigger shallow slope t failures. I. Slopes should not be altered without expert consultation. Whenever a ' homeowner plans a topographic modification of a lot or slope, a qualified geotechnical consultant should be contacted. ' J. If unusual cracking, settling, or earth slippage occurs on the property, the owner should consult a qualified geotechnical consultant immediately. ' K. The most common causes of slope erosion and shallow slope failures are as follows: ' • Gross neglect of the care and maintenance of onsite slopes and drainage devices ' • Inadequate and /or improper planting. Barren areas should be replanted as soon as possible. ' • Excessive or insufficient irrigation or diversion of runoff over the slope. ' L. Property owners should not let conditions on their property adversely impact their neighbors. Cooperation with neighbors could prevent problems ' and increase the aesthetic attractiveness of the community.