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HomeMy WebLinkAboutCT 2017-0004; SIX ON MADISON; GEOTECHNICAL INVESTIGATION; 2017-01-23ALLIED EARTH TECHNOLOGY 7915 SILVERTON AVENUE, SUITE 317 SAN DIEGO, CALIFORNIA 92126 TEL : (858) 586-1665 (619) 447-4747 E-MAIL : R QBE R T A £ T A 0 L, C 0 Tvl ROBERT CHAN, P.E. GEOTECHNICAL INVESTIGATION PROPOSED SIX-UNIT CONDOMIIUM BUILDING SITE 3095 MADISON STREET CARLSBAD, CALIFORNIA FOR OAK & MADISON LLC PROJECT NO. 17-1106ES JANUARY 23, 2017 RECEIVED AUG U:i 2017 CITY OF CARLSBAD PLr.^!^J!^i3 D!V!£10M ALLIED EARTH TECHNOLOGY 7915 SILVERTON AVENUE, SUITE 317 SAN DIEGO, CALIFORNIA92126 TEL : (858) 586-1665 (619) 447-4747 e-mail: LCROBERTAETOAOL.COM ROBERT CHAN, P.E. January 24, 2017 Oak &. Madison LLC 7851 Mission Center Court San Diego, CA. 92108 Attn Mr. Mehran Saberi Subject: Project No. 16-1106E5 Geotechnical Investigation Proposed Six-Unit Condominium Building Site 3095 Madison Street Carlsbad, California Gentlemen : In accordance vi/ith your request, we have completed the geotechnical investigation for the proposed six-unit condominium building site on subject property, more specifically referred to as being Lot Nos. 31 and 32, in Block No.' 39 and adjacent street closing, according to Map thereof No. 775 (APN 203-305-10-00), in the City of Carlsbad, State of California.. We are pleased to submit the accompany geotechnical investigation report to present our findings, conclusions and recommendations relative to the proposed development of the site. The geotechnical Investigation was conducted under the supervision of the undersigned. The scope of our Investigation included field exploration, laboratory testing and soil engineering analysis. No major adverse geotechnical conditions were encountered which would prohibit the currently proposed development of the site. Project No. 16-1106E5 Oak & Madison LLC 165-175 Pine Avenue 01/24/17 Page 2 This opportunity to be of service is sincerely appreciated. Should you have any questions, please do not hesitate to ^ espectfuiiy subrr^ed, ALLIED EARTH TECUWdlOGY 24613ROBERT CHA^ P.E. CIV\u c;;; 00195 12/31/ TABLE OF CONTENTS Page No. INTRODUaiON 1 DESCRIPTION OF PROJECT 1 SCOPE OF WORK 1 FIELD INVESTIGATION 2 LABORATORY TESTS 3 SITE DESCRIPTION 3 PROPOSED SITE DEVELOPMENT 4 GENERAL GEOLOGY AND SUBSURFACE SOL CONDITIONS Regional Geology 4 Site Geology and Subsurface Soil Conditions 4 Tectonic Setting 5 GROUNDWATER 5 GEOLOGIC HAZARDS Ground Shaking 6 Surface Rupture 6 Liquefaction Potential 7 Landslides 7 FINDINGS, CONCLUSIONS AND RECOMMENDATIONS General 7 Expansion Index of On-Site Soils 8 SulfaTe Content of On-Site Soils 8 TABLE OF CONTENTS (Conf nd) Page No. Grading 8 Foundation and Slab Design 9 Under-Slab Vapor Retarders 10 Retaining Wall Design 11 Seismic Earth Pressures 12 Lateral Loading 12 Seismic Coefficients 13 Concrete Flatwork 14 Surface Drainage and Maintenance 14 Foundation Plans Review 14 LIMITATION AND UNIFORMITY OF CONDITIONS... 14 Figure No. 1 - Site Location Map Figure No. 2 - Approximate Location of Exploratory Trenches Figure Now. 3 to 6, inclusive - Trench Log Sheet Appendix i- General Grading and Earthwork Specifications Appendix II - Laboratory Test Results Appendix ill- References ALLIED EARTH TECHNOLOGY 7915 SILVERTON AVENUE, SUITE 317 SAN DIEGO, CAUFORNIA 92126 TEL:(858)586-1665 (619) 447-4747 E-MAIL: ROBERTAETPAOLCOM ROBERT CHAN, P.E. January 24, 2017 GEOTECHNICAL INVESTIGATION INTRODUCTION This report presents the findings and conclusions of a geotechnical investigation conducted at the site of a 6-unit condominium building on subject property, located at 3095 Madison Street, in the City of Carlsbad, State of California. Subject property is more specifically referred to as being Lot Nos. 31 and 32, in Block No. 39 and adjacent street closing, according to Map thereof No. 775 (APN 203-305-10-00). The location of the property is shown on Figure No. 1, entitled, "Site Location Map". DESCRIPTION OF PROJECT It is our understanding that a 6-unit condominium building is proposed for the site. The proposed structure will consist of 3 stories of condominium space over a parking level; of wood- frame/stucco and slab-on-grade construction. SCOPE OF WORK The objectives of the investigation were to Inspect and determine the subsurface Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 2 3095 Madison Street geotechnlcai conditions and certain physicai engineering properties of the soiis beneath the site, and to evaiuate any potentiai adverse geotechnicai conditions that could affect the proposed project, in order that engineering recommendations could be presented relative to the safe and economical development of the site; and checking and design of foundation for the proposed structure. In order to accomplish these objectives, four exploratory trenches were excavated and inspected, and representative samples of the subsurface soils were collected for laboratory testing and analysis. Tfie data derived from the field observations and laboratory test results were reviewed and analyzed, and a summary of our preliminary findings, opinions and recommendations is presented in this report. FIELD INVESTIGATION The field exploratory phase of our investigation was performed on October 7, 2016, and involved a reconnaissance of the property and the excavation of four exploratory trenches with a tractor-mounted backhoe equipped with a 24-lnch bucket. The exploratory trenches were excavated at accessible locations on the site where the most useful information relative to subsurface geotechnicai conditions may be obtained. The Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 3 3095 Madison Street exploratory trenches were excavated to depths varying from 7 to 9 feet below existing ground surface. The location of the exploratory trenches is shown on Figure No. 2, entitled, "Approximate Location of Exploratory Trenches". The soil types encountered In the exploratory trenches were recorded at the time of excavation, and Is shown on Figure Nos. 3 to 6, Inclusive, each entitled, "Trench Log Sheet". The soils were visually and texturally classified by the field Identification procedures set forth on the Unified Soil Classification Chart. Representative samples were obtained at varlouls depths In the exploratory trenches. LABORATORY TESTS The samples collected during our field Investigation were subjected to various tests In the laboratory to evaluate their engineering characteristics. The tests were performed In accordance with current A.S.T.M. testing standards or other regulatory agency testing procedures. A summary of the tests that were performed and the final test results are presented in Appendix II hereto. SITE DESCRIPTION Subject property Is a rectangular-shaped lot of 8,400 square feet, situated In the northwest corner of Oak Avenue and Madison Street. Currently, the site Is vacant,, and covered with a sparse growth of grass and weeds. Project No. 16-1106E5 Oak & Madison LLC Ql/1^/11 Page 4 3095 Madison Street The property is located in a developed area of Carlsbad. The site is bounded on the east by Madison Street; on the south by Oak Avenue; on the west by an alley, and on the north by a converted office building. PROPOSED SITE DEVELOPMENT Site development will consist of the construction of a 3 story condominium building over a street level parking garage. The proposed structure will be of wood-frame/stucco and slab-on- grade construction. GENERAL GEOLOGY AND SUBSURFACE SOIL CONDITIONS Regional Geology The subject property is located within the southern coastal strip region of the Peninsular Range Geomorphic Province of California. This geomorphic province is characterized by mountainous terrain to the east composed mostly of Mesozoic igneous and metamorphic rocks and relatively low-lying coastal terraces to the west underlain by late Cretaceous, Tertiary and Quaternary sedimentary rocks. This area of the City of Carlsbad, including the site, occurs within the westerly region and is underlain by Quaternary sedimentary rocks. Site Geology and Subsurface Soil Conditions A review of geologic maps as well as observations made during our subsurface exploration indicates that the general area is underlain by late to middle Pleistocene Old Paralic Deposits Unit 6-7. On subject property, these Old Paralic Deposits were encountered in the form of medium Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 5 3095 Madison Street dense to dense brown fine sands. The Old Paralic Deposits were overlain by a loose residual/topsoil layer on the order of 6 to 12 inches in thickness. Tectonic Setting No evidence of faulting was noted during our subsurface reconnaissance or in our exploratory trenches. A review of available geologic literature did not reveal any major faulting in the area, it should be noted that much of southern California, including much of the City of Carlsbad, is characterized by a series of Quaternary-age fault zones which typically strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as active while others are classified as only potentially active according to the criteria of the California Division of Mines and Geology. A review of available geologic maps indicate that the subject property is approximately 15 miles (9.4 km) from the Newport-lnglewood Fault zone, and 20 miles (12.5 km) from the Elsinore-Julian Fault zone. GROUNDWATER No groundwater was encountered in the exploratory trenches to the maximum depth of exploration at 9 feet; and no groundwater was encountered to a depth of 25 feet at a nearby site, approximately Y* mile to the southwest. No major groundwater related problems, either during or after construction, are anticipated. However, it should be recognized that minor Project No. 16-1106E5 Oak & Madison LLC 0/12/17 Page 6 3095 Madison Street seepage problems may occur after development of a site even where none were present before development. These are usually minor phenomena and are often the results of an alteration of the permeability characteristics of the soils; an alteration in drainage patterns due to grading; and an increase in the use of irrigation water. Based on the permeability characteristics of the soils and anticipated usage of the development, it is our opinion that any seepage problems which may occur will be minor in extent. It is further our opinion that these problems can be most effectively corrected on an individual basis if and when they develop. GEOLOGIC HAZARDS Ground Shaking -_The most likely geologic hazard to affect the site is ground shaking as a result of movement along one of the active fault zones mentioned above. For seismic design purposes, soil parameters in accordance with the 2013 edition of the California Building Code were determined, and presented hereinafter. Surface Rupture - Surface rupture is the result of movement of an active fault reaching the surface. According to available geologic maps, there are no earthquake faults on the property, or in the general area, and no faults were observed during our site investigation. Based on our observations and experience, it is our opinion that there is little probability of surface rupture due to faulting beneath the site. However, lurching and ground cracking are Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 7 3095 Madison Street a possibiiity as a result of a significant seismic event on a regional active fault. Liquefaction Potential - in consideration of the competent formationai soils underlying the site; the soil types encountered; and the lack of a high groundwater level, It is our opinion that the soil liquefaction does not present a significant geotechnical hazard to the proposed site development. Landslides Subject property is situated on level terrain and underlain by competent formationai soils. A review of available geologic maps did not reveal the presence of any ancient landslides on subject or adjacent properties. The potential for landslides on subject or adjacent properties is considered minimal. FINDINGS. CONCLUSIONS AND RECOMMENDATIONS General 1. Based on the results of the investigation, It is our opinion that the currently proposed site development Is feasiible from a geotechnical engineering standpoint, provided that the recommendations presented in this report are incorporated into the design plan(s) and are properly Implemented during the construction phase. 2. It Is noted that some of the recommendations may have to be modified and supplemental recommendations may have to be presented, depending on the actual subsurface conditions encountered during construction. Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 8 3095 Madison Street Site grading and earth work construction wiii not impact the adjacent properties provided our recommendations are incorporated into the final design and implemented during the construction phase. Additional field recommendations, however, may also be necessary and should be given by the project geotechnicai consultant for the protection of adjacent properties and should be anticipated. Expansion Index of On-Site Soils 4. The soils encountered on the site possess very low expansion potential (Expansion lndex= 8). Sulfate Content of On-Slte Soils 5. The soils encountered on the site are subject to negligible sulfate exposure (sulfate content of 15). Grading 6. it is recommended that ail earthwork be accomplished in accordance with the Grading Ordinance of the City of Carlsbad, current edition of the California Building Code, Appendix I attached hereto, entitled, "General Grading and Earthwork Specifications", and recommendations as presented in this Section. 7. Where the recommendations of this Section of the report conflict with those of Appendix I, this Section of the report takes precedence. Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 9 3095 Madison Street 8. Grading should begin with the clearing and grubbing of the site. Ail debris should be hauled away and hauled away to a City-approved dump site. 9. After clearing and grubbing of the site is completed, it is recommended that the upper soils be scarified to a depth of 12 Inches, and then properly moistened, prior to the placement of any additional fill soils. 10. Additional fill soils may be required to achieve proposed finished grade. It is recommended that these import fill soils consist of soils having low expansion potential (expansion index < 50); and be approved at the borrow source by our firm prior to importation. 11. All fill soils are to be compacted to at least 90 percent of maximum dry density at near optimum moisture content in accordance with ASTM D1557. Foundation and Slab Design • 12. it is recommended that a safe allowable soil bearing value of 2,000 pounds per square foot be used for the design and checking of continuous footings that are 12 inches in minimum horizontal dimension, and isolated pier footings that are 15 inches in minimum horizontal dimension; and are embedded at least 18 inches below the lowest adjacent ground surface. Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 10 3095 Madison Street The above safe allowable soil bearing value may be increased by one-third when considering wind and/or seismic forces. 13. The settlement of foundation, when designed and loaded as outlined above, are expected to be less than % inch total and K inch differential over a span of 40 feet. 14. It is recommended that all continuous footings be reinforced with a minimum of 4 #5 rebars; two rebars located near the top, and the other two rebars near the bottom of the footings. All isolated per footings should be reinforced with a minimum of 2 #5 rebars in both directions, placed near the bottom of the footings. 15. The concrete slab-on-grade should be 5 inches in thickness, and be reinforced with #3 rebars @ 18 inches on center in both directions, placed at mid-height of concrete slab. The slab reinforcement should extend into the perimeter footings at least 6 inches. Under-Slab Vapor Retarders 16. The concrete slab should be underlain by 4 inches of clean sand, a 10-mil plastic membrane moisture barrier, and another inch of clean sand cover. The seams of the plastic membrane should be sealed and extend at least 12 inches down the sides of the interior and perimeter footings. The membrane should be placed in accordance with the recommendations and consideration of ACI302, "Guide for Concrete Floor and Slab- Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 11 3095 Madison Street Construction" and ASTM 1643, "Standard Practice for instaliation of Water Vapor Retarder Used in Contact with Earth or Granuiar Fili Under Concrete Siabs". The above foundation and siab reinforcement recommendations are based on soii characteristics, and should be superseded by the requirements of the project architect. Retaining Wall Design 22. it is recommended that retaining waiis be designed to withstand the pressure exerted by equivalent fluid weights given below : Equivalent Backfill Fluid Surface Pressure (horizontal: vertical) (pcf) Level (Active) 35 2:1 " 50 Level (Restrained) 50 2:1 " 65 The above values assume that the retaining waiis have a granuiar backfill. 23. On-site soils having very low expansion potential should be used as backfill behind the retaining waiis. Ail backfill soils are to be compacted to at least 90 percent of maximum dry density in accordance with ASTM D1557. 24. Ail retaining wails should be supplied with a backfill drainage system adequate to prevent Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 12 3095 Madison Street the buildup of hydrostatic pressure. The subdrain should consist of one-inch gravel and a perforated pipe near the bottom of the retaining wall. The width of this subdrain should be at least 12 inches, and extend atieast2/3 height of the retaining wail. The subdrain should be enclosed in a geotextiie fabric such as Mirafi 140N or equal. Manufactured subdrain products such as Miradrain 2000 series or "J" Drain 400 series may also be used. Seismic Earth Pressures 25. Seismic earth pressure for cantilever retaining wail can be taken as an inverted triangular distribution with a maximum pressure at the top equal to 12H pound per square foot (with H being the height of retained earth in feet). For restrained walls, such as basement retaining wails, the seismic earth pressure should be increased to 17H pound per square foot. The above pressures are in addition to the static design wall load. The allowable passive pressure and bearing capacity can be increased by 1/3 in determining the stability of the retaining wail. A factor-of-safety of 1.2 can be used in determining the stability of the retaining wall under seismic conditions. Lateral Loading 26. To resist lateral loads, it is recommended that the pressure exerted by an equivalent fluid weight of 250 pounds per cubic foot be used for footings or shear keys poured neat against competent natural or compacted fill soils. The upper 12 inches of material in areas not protected byfloor slabs or pavements should not be included in the design for passive Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 13 3095 Madison Street resistance. This value assumes that the horizontal distance of the soil mass extends at least 10 feet or three times the height of the surface generating the passive pressure, whichever is greater. 27. A coefficient of sliding friction of 0.35 may be used for cast-in-piace concrete over competent natural or compacted fill soils. Footings can be designed to resist lateral loads by using a combination of sliding friction and passive resistance. The coefficient of friction should be applied to dead load forces only. Seismic Coefficients 28. The seismic design factors were determined in accordance with 2013 California Building Code, and presented as follows : Site Coordinates: Latitude = 33.1597 Longitude = -117.3461 Site Class: = C Spectral Response Acceleration At Short Periods Ss = 1.151 Spectral Response Acceleration At 1-second period SI = 0.441 Sml = 1.151 Sds = 0.767 Sdl = 0.400 Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 14 3095 Madison Street Concrete Flatwork 29. In consideration of the on-slte soil conditions, it is recommended that concrete flatwork be a minimum of 3 34 inches in thickness, and be reinforced with 6x6-W1.4xW1.4 (6x6- 10/10)welded wire fabric, placed at mid-height of concrete slab. One-Inch expansion joints should be provided at 15-foot intervals, with % inch weakened plane contraction joints at 5-foot intervals. Surface Drainage and Maintenance 30. Adequate drainage control and proper maintenance of all drainage facilities are imperative to minimize infiltration of surface water into the underlying soil mass in order to reduce settlement potential and to minimize erosion.; the building pad should have drainage swales which direct storm and excess irrigation water away from the structures and into the street gutters or other drainage facilities. No surface runoff should be allowed to pond adjacent to the foundation of structures. Foundation Plans Review 31. It is recommended that our firm review the final foundation plans for the proposed site development to verify their compliance with our recommendations. UMITATION AND UNIFORMITY OF CONDITIONS 1. The preliminary findings and recommendations contained in this report pertain only to the site investigated and are based on the assumption that the soil conditions beneath I )^ Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 15 ^ 3095 Madison Street ^ the entire site do not deviate substantiaiiy from those disciosed in the expioratory > ^ trenches, if any variations or undesirabie conditions are encountered during grading, or j if the scope of the project differs from that planned at the present time, our firm should I be notified in order that supplemental recommendations can be presented, if necessary. > ^ 2. This report is issued with the understanding that it is the responsibility of the Owner, or ) ^ his representative, to ensure that the information and recommendations presented ) > > > ) or his representative, will also be responsible for taking the necessary measures to ensure > ) that the Contractor and subcontractors properly carry out the recommendations in the >j field. > I 3. Professional opinions and recommendations presented in this report are based partly on our evaluation and analysis of the technical information gathered during the study, partly ^ on the currently available information regarding the proposed project, and partly on our previous experience with similar soil conditions and projects of similar scope. Our study has been performed in accordance with the minimum standards of care exercised by other professional geotechnicai consultants currently practicing in the same locality. We herein are brought to the attention of the Project Architect and Engineer and are incorporated into the plans and specifications for the project. Furthermore, the Owner, Project No. 16-1106E5 Oak & Madison LLC 01/24/17 Page 16 3095 Madison Street do not, however, guarantee the performance of the proposed project in any respect, and no warranties of any kind, expressed or implied, are made or intended in connection with the study performed by our firm. 4. The findings and recommendations contained in this report are valid as of the present date. However, changes in the conditions of the property could occur with the passage of time, whether they be due to naturai processes or due to man-made actions on the subject and/or Adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalided, wholly or partially, by changes outside of our control. Therefore, this report is subject to review by our firm and should not be relied upon after a period of two years. Figure Nos. 1 to 6, inclusive, and Appendices I, li and III are parts of this report. PROJECT NO. 16-1106 E5 FIGURE N0.1 140.00' 1 im ICNEOrEmOSCT)DMaopeoaow.TYT T#1 lAWSCAflNG LfNDSC>m3 140.00' NOT TO SCALE OAK AVENUE APPROXIMATE LOCATION OF EXPLORATORY TRENCHES LEGEND ^5, APPROXIMATE LOCATION OF EXPLORATORY TRENCH PROJECT NO. 16-1106 E5 FIGURE N0.2 TRENCH LOG SHEET FT. TRENCH NO. 1 Elev. 49 msl DESCRIPTION SOIL TYPE -0 1 Bro\A/n, damp, loose (Topsoils) FINE SAND (SP) Brown, moist, medium dense FINE SAND (SP) 2 (Old Paralic Deposit Unit 6-7) • t 3 % ^ 4 ©10.1*113.3*92.5%* 1 5 6 7 Dense t 8 •9 BOTTOM OF TRENCH (No Refusal) LEGEND O - Indicates representative sample ^ - Indicates iin-situ density test Project No. 17-1106E5 Figure No. 3 TRENCH LOG SHEET TRENCH NO. 2 Elev. 49 msl FT.DESCRIPTION SOIL TYPE \ 0 1 Brown, damp, loose (Topsoils) FINE SAND (SP) Brown, moist, medium dense FINE SAND (SP) - 2 (Old Paralic Deposit Unit 6-7) " -3 ' X 4 -5 (T) Dense 10.8*115.0*93.9%* ' 6 i 7 BOTTOM OF TRENCH (No Refusal) Project No. 17-1106E5 Figure No. 4 TRENCH LOG SHEET TRENCH NO. 3 Elev. 48 msl FT.DESCRIPTION SOIL TYPE • 0 1 Brown, damp, loose (Topsoils) FINE SAND (SP) Brown, moist, medium dense FINE SAND (SP) - c 2 (Old Paralic Deposit Unit 6-7) c 3 4 • 5 Dense, slight cementation 6 7 - 8 BOTTOM OF TRENCH (No Refusal) Project No. 17-1106E5 Figure No. 5 TRENCH LOG SHEET TRENCH NO./^ Elev. 48 msl FT.DESCRIPTION SOIL TYPE 0 1 Brown, damp, loose (Topsoils) FINE SAND (SP) - '2 Brown, moist, medium dense (Old Paralic Deposit Unit 5-7) FINE SAND (SP) 3 N i / 4 5 Dense 6 i 7 y 8 BOTTOM OF TRENCH (No Refusal) Project No. 17-1106E5 Figure No. 6 APPENDIX I GENERAL GRADING AND EARTHWORK SPECIFICATIONS 1.0 General 1.1 All earthwork shall be accomplished in accordance with the Grading Ordinance of the Agency having jurisdiction; Chapter 18 and 18 A, and Appendix J of the 2013 edition of the California Building Code; Appendix I hereinafter, and recommendations as presented in the Geotechnical Report. 1.2 These recommended grading and earthwork specifications are intended to be a part of and to supplement the Geotechnical Report(s). In the event of a conflict, the recommendations of the Geotechnical Report(s) will supersede these specifications. Observations during the course of earthwork operations may result in additional, new or revised recommendations that could supersede these specifications and/or the recommendations in the Geotechnical Report(s). 1.3 The Owner or his authorized representative shall procure the services of a qualified Geotechnical Consulting Firm, hereinafter to be referred to as the "Geotechnical Consultanf (often the same entity that produced the Geotechnical Report(s). 1.4 The Geotechnical Consultant shall be given a schedule of work by the Earthwork contractor for the subject project, so as to be able to perform required observations; testing and mapping of work in progress in a timely manner. 1.5 The work herein includes all activities firom clearing and grubbing through fine grading. Included are trenching, excavating, backfill compaction and grading. All work shall be as shown on the approved project drawings. 1.6 The Geotechnical Consultant or a qualified representative shall be present on the site as required, to observe, map and document the subsurface exposures so as to verify the geotechnical design suppositions. In the event that observed conditions are found to be significantly different from the interpreted conditions during the design phase, the Geotechnical Consultant shall notify the Owner, recommended appropriate changes in the design to suit the observed conditions and notify the agenc(ies) having jurisdiction, where required. Subsiuface areas to be geotechnicaUy observed, mapped, record elevations or tested included cleared natural groimd for receiving fill or structures, "remedial removal" areas, key bottoms and benches. APPENDIX I Page 2 1.7 The guidelines contained herein and any standard details attached herewith represent this firm's recommendations for the grading and all associated operations on the subject project. These guidelines shall be considered to be a part of these Specifications. 1.8 If interpretation of these guidehnes or standard details result in a dispute(s), the Geotechnical Consultant shall conclude the appropriate interpretation. 1.9 The Geotechnical Consultant shall observe the processing of subgrade and fidl materials and perform the necessary compaction testing. The test results shall be provided to the Owner and the Contractor and if so required, to the agenc(ies) having jurisdiction. 1.10 The Geotechnical Consultant shall not provide "supervision" or any "direction" of work in progress to the Earthwork Contractor, or to any of the Contractor's employees or to any of the Contractor's agent. 1.11 The Earthwork Contractor ; The Earthwork Contractor (contractor) shall be qualified, experienced and knowledgeable in earthwork logistics; preparation and processing of groxmd to receive fiU, moisture condition and processing of fill and compacting fiU. The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance n with the plans and specifications. The Contractor shall prepare and submit to the Owner and the Geotechnical Consultant a work plan that indicates the sequence of earthwork grading, the number of "spreads" of work and the estimated quantities of daily earthwork contemplated for the site prior to commencement of grading. The Contractor shall inform the Owner and the Geotechnical Consultant of change in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of aU grading operations. The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading Codes and agency ordinances, these Specifications and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soils. APPENDIX I Page 3 improper moisture conditions, inadequate compactions, insufficient buttress key size, adverse weather, etc. are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the Owner that construction be stopped imtil the conditions are rectified. 2.0 Preparation of Areas to be Filled 2.1 Clearing and grubbing : vegetation, such as brush, grass, roots, and other deleterious materials shall be sufficiently removed and properly disposed of in a method acceptable to the Owner, governing agencies, and the Geotechnical Consultant. The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fill lifts shall contain more than 5 percent of organic matter. Nesting of the organic materials shall not be allowed. If potentially hazardous materials are encountered, the Contractor shall stop work in the affected areas, and a hazardous material specialist shall be informed immediately for proper evaluation and handling of these materials prior to continuing to work in that area. As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fine and/or imprisonment and shall not be allowed. Materials used for fill, either imported or on-site, shall not contain hazardous materials as defined by the California Code of Regulations, Title 22, Division 4, n Chapter 30, Article 9 and 10; 40 CRT; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request firom the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials are not hazardous as defined by applicable laws and regulations. APPENDIX I Page 4 2.2 Any asphaltic pavement material removed during clearing operations should be properly disposed of at an approved off-site facility. Concrete fragments which are free of reinforcing steel may be placed in fills, provided that they are placed in accordance with Section 3.1 of this document. 2.3 During grading, soil or groundwater conditions other than those identified in the Geotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the significance of the unanticipated conditions. 2.4 Processing : Existiug ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Existing grmmd that is not satisfactory shall be over-excavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay clumps or clods and the working surface is reasonable uniform, flat, and free of uneven features that would inhibit uniform compaction. 2.5 Over-excavation ; In addition to removals and over-excavations recommended in the approved geotechmcal report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich highly fiactured or otherwise unsuitable ground shall be over- excavated to competent ground as evaluated by the Geotechmcal Consultant during grading. 2.6 Benching : Where fills are to be placed on ground with slopes steeper than 5 ; 1 (horizontal : vertical), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep into competent material as evaluated by the Geotechmcal Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechmcal Consultant Fill placed on ground sloping flatter than 5 : 1 (horizontal: vertical) shall also be benched or otherwise over-excavated to provide a flat subgrade for the fill. 2.7 Evaluation/Acceptance of Fill Areas : All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded and/or tested prior to being accepted by the Geotechmcal Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechmcal Consultant prior to fill placement. A licensed surveyor shall provide the survey control for determining elevation of processed areas, keys and benches. APPENDIX I Page 5 3.0 Fill Material 3.1 General: Materials to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement Soils of poor quality, such as those with unacceptable gradation, high expansion potential or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill materials. 3.2 Oversized Material : Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches shall not be buried or placed in fill unless location, materials and placement methods are specifically accepted by the Geotechmcal Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finished grade or within 2 feet of future utihties or underground construction. 3.3 Import : If importing of fill materials is required for grading, proposed import material shall meet the requirements of Section 3.1 The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before unporting begins so that its suitability can be determined and appropriate tests performed.' 4.0 Fill Placement and Compaction 4.1 FiU Layer : Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near vertical layers generally not exceeding 8 inches in thickness when compacted. The Geotechnical Consultant may accept thicker layers if testing indicates that the grading procedure can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout 4.2 Fill Moisture Conditioning : Fill soils shall be watered, dried back blended, and/or mixed as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557). APPENDIX I Page 6 4.3 Compaction of Fill : After each layer has been moisture-conditioned, mixed and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM D1557). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity. 4.4 Compaction of Fill Slopes ; In addition to normal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increment of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant. Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum dry density per ASTM Test Method D1557. 4.5 Compaction Testing ; Field tests for moisture content and relative compaction of the fill soils shall be performed by the Geotechnical Consultant. Location and firequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations wiU not necessarily be selected on a random basis. Test locations shall be selected to verily adequacy of compaction levels in areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches). 4/6 Frequency of Compaction Testing : Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment. In addition as a guideline, at least one test shaU be taken on slope faces for each 5,000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill construction is such that the testing schedule can be accomplished by the Geotechnical Consultant The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met 4.7 Compaction Test Locations : The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant cdan determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance oflOO feet and vertically less than 5 feet apart fi*om potential test locations shaU be provided. APPENDIX I p,g,7 5.0 Subdrain Installation Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. 6.0 Excavation Excavations, as well as over-excavation for remedial purpose, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shaU be determined by the Geotechmcal Consultant based on the field evaluation of exposed conditions during grading. Where fill-overcut slopes are to be graded, the cut portion of the slopes shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction of the fill portion of the slope, unless otherwise recommended by the Geotechnical Consultant. 7.0 Trench Backfill 7.1 The Contractor shall follow all OSHA and Cal/OSHA requirements for safety of trench excavations. 7.2 All bedding and backfill of utility trenches shall be done in accordance with the appUcable provisions of Standard Specifications of Public Works Construction. Bedding material shall have a Sand Equivalent greater than 30 (SE > 30). The bedding shall be placed and compacted to at a minimum of 90 percent of maximum dry density fix)m 1 foot above the top of the conduit to the surface. 7.3 The jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant 7.4 The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill. Page 8 appendix I 7.5 Lift thickness of trench backfill shaU not exceed those allowed m the Standari Specifications of Public Works Construction unless the Contractor can demonstrate to the Geoteehnical Consultant that the fill lift can be compacted to the mrmmum relative compaction by his alternative equipment and method. FILL SLOPE PROJECT PLAN 1 TO 1 Min FROM TOE OF SLOPE TO APPROVED GROUND EXISTING GROUND SURFACE FILL OVER CUT SLOPE CH HEIGHT REMOVE NSUITABLE MATERIAL2' Min. KEY DEPTH BENCH KEY NATURAL GROUND REMOVE UNSUITABLE MATERIAL NATURAL GROUND CUT FACE TO BE CONSTRUCTED PRIOR TO FILL X PLACEMENT DESIGN SLOPE NATURAL ROUND CUT FACE SHALL BE CONSTRUCTED PRIOR ^ Min. TO HLL PLACEMENT TO KEY DEPTH ASSURE ADEQUATE GEOLOGIC C0NDJ310KS'''' CUT OVER FILL SLOPE PROJECT PLAN 1 TO I Min. FROM TOE OF SLOPE TO APPROVED GROUND BENCH HEIGHT FOR SUBDRAINSEE STANDARD DETAIL "C DVE UNSUITABLE -MATERIAL BENCHING SHALL BE DONE WHEN SLOPES ANGLE IS EQUAL TO OR THAN 5:1. MAXIMUM BENCH HBGHT SHALL BE 4 FEET. MAXIMUM FILL WIDTH SHALL BE 8 FEEl 2' KEY DEPTH n KEYING AND BENCHING DETAIL A ALLIED EARTH TECHNOLOGY OVER SIZE / WINDROW OVER SIZE ROCK IS lARGER THAN INCHES IN LARGEST DIMENSION EXCAVATE A TRENCH IN THE COMPACTED FILL DEEP ENOUGH TO BURY ALL THE ROCK BACKFILL WITH GRANULAR SOIL JETTED OR FLOODED IN PLACE TO FILL ALL THE ROCK VOIDS DO NOT BURY ROCK WITHIN 10 FEET OF FINISH GRADED. WINDROW OF BURIED ROCK SHALL BE PARALLEL TO THE FINISH SLOPE FILL. JEHED OR FLOODED GRANULAR MATERIAL SECTION JEHED OR FLOODED GRANULAR MATERIAL' PROFILE ALONG WINDROW EXISTING GROUND SURFACE ISUITABLE TERIAL SUE SEE DETAIL BELOW CALTRAN CLASS II PERMEABLE OR # 2 ROCK ( 3 CU. FT/FT) WRAPPED IN FILTER FABRIC 12' Min. OVERLAP FROM THE TO_P HOG RING TIED EVERY 6 FEET POSITIVE SEAL SHOULD BE PROVIDE AT THE JOINT FILTER FABRIC MIRAFI 140 OR APPROVED EQUIV/1 DETAIL OF CANYON SUBDRAIN TERMINAL DESIGN FINISH GRADE OUTLET PIPE (NON PERFORATED PIPE ) T- CON COliECnON PIPE TO OUTLET PIPE "Sr"'' '-V • .V •: -.'t •'> 'V', -V • .V '-V < ,1' 'V • ''' FILTER FABRIC (MIRAFI 140 N OR APPROVED EQUIVALENT 15' Min. , I ,.r NON PERFORATED "|5'Mln:| PERFORATED / \ #2 WRAPPED IN FILTER 6' 0 Min. PIPE (6' Min-P ^ FABRIC OR CALTRANS CLASS II PERMEABLE CANYON SUBDRAIN DETAILS DETAIL C ALLIED EARTH TECHNOLOGY 15' Min. OUTLET PIPES, 4- NGN PERFORATED, 100' Max. O.C. HORIZONTAL, 30' Max. O.C. VERTICAL 2' Min. KEYDE BENCH KEY FILTER FABRIC MIRAFI 140 OR APPROVED QUIVALENTCALTRAN CLASS II 9ERMEABLE OR # 2 ROCK (3 qU. FT/FT) WRAPPED IN FILTER FABRIC 12* Min. OVERLAP FROM THE T HOG RING TIED EVERY 6 FE POSITIVE SEAL SHOULD BE PROVIDE AT THE JOINT 5-0% Min. f-iT'« CTION FOR COLLECTION PIPE TO OUTLET PIPE OUTLET PIPE (NON PERFORATED PIPE ) SUBDRAIN INSTALLATION- subi^rajn collector pipe shall be installed with perforahons down or UNLESS otherwise DESIGNH) BY THE GEOTECHNICAL CONSUITAN. OUTLET SHALL BE NON-PERFORATED PIPE. THE S UBDRAIN PIPE SHALL HAVE AT LEAST 8 PERFORATIONS UNIFORMLY SPACED PER FOOT PERFORATION SHALL BE T/4" TO T/2" IF DRILLED HOLES ARE USED. ALL SUBL5RA1N PIPES SHALL HAVE A GRADIENT AT LEAST 2% TOWARD THE OUTLET SUBDRAIN PIPES-SUBDRAIN PIPE SHALL BE ASTMD 2751, SDR 23.5 OR ASTMD 1527, schedule 40, OR ASTMD 3034, SDR 23.5, schedule 40 polyvbm choride plastic (pvq pipe. ALL outlet pipe shall BE placed IN A TRENCH NO WIDER THAN TWICE THE SUBDRAIN PIPE, PIE SHALL BE IN SOIL OF SE>30 JETTED OR FLOODED IN PLACED EXCEPT FOR THE OUTSIDE 6 FEET WHICH BE NATIVE SOIL BACKFILL BUHRESS OR REPLACEMENT SUBDRAIN DETAIL D ALLIED EARTH TECHNOLOGY EXISTING GROUND PROJECT PLAN 1 TO 1 Min FROM TOP OF SLOPE TO OUTSIDE EDGE OF KEY FINISH SLOPE SURFACE SURFACE in: KEY DEPTH BENCH K .VATION DEPTH AND OMPACnON MAY BE RECOMMENDED E CONSULTAN BASED ON ACTUAL ID CONDITION ENCOUNTERED OVERBURDEN OR UNSUITABLE MATERIAL NOTE: SUBDRAIN DETAILS AND KEY WDTH RECOMMENDATIONS TO BE PROVIDED BASED ON EXPOSED SURFACE CONDITIONS HILLSIDE STABILITY FILL DETAIL E ALLIED EARTH TECHNOLOGY Project No. 16-1106E5 Oak & Madison LLC 01/24/17 3095 Madison Street APPENDiX ii LABORATORY TEST RESULTS 1. The maximum dry density and optimum moisture content of the fiii soiis encountered were determined in accordance with ASTM D1557, Method A. The resuits of the test are presented as follows : Maximum Optimum Soil Dry Density Moisture Content Description (Ibs/cu.ft.) (% Dry Wt.) Trench#! Brown fine sand 122.5 11.5 Sample #1 (SP) Depth 3.0' 2. The Expansion index of the most clayey soils was determined In accordance with ASTM D4928-08. The resuits of the test are presented as follows: Soil Expansion Description Index Trench#! Brown fine sand 8* Sample#! (SP) Depth 3.0' ■^Considered to possess very low expansion potential Project No, 16-1106E5 Oak & Madison LLC 01/24/17 3095 Madison Street APPENDIX il LABORATORY TEST RESULTS (CONT'ND) 3. The suifate content of the soils encountered were determined in accordance with California Test No. 317. The results are presented below : Suifate Soil Content Description (ppm) Trench #1 Brown fine sand 15 Negligible Sample #1 Depth 3.0' Project No. 16-1106E5 Oak & Madison LLC 01/24/17 3095 Madison Street APPENDIX III REFERENCES BGI Architecture - Building Plans for Six On Oak Condominiums. California Building Code, Volume 1 & 2, International Conference of Building Officials, 2001 California Department of Conservation, Division of Mines and Geology (California Geological Survey), 1997. Guidelines for Evaluating and Mitigating Seismic Hazards in California, DMG Special Publications 17. 71p. Foundation and Earth Structures, Naval Facilities Engineering Command, DM7.02 Green Book" Standard Specifications for Public Works Construction, Public Works Standards, 2013 edition. Kennedy, M.P. and Tan S.S., 2005 Geologic Map of the San Diego SCF x 60' Quadrangle, California Geologic Survey and U.S. Geological Survey digital map series.