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Home My WebLink AboutCT 2017-0006; ROOSEVELT TOWNHOMES; GEOTECHNICAL INVESTIGATION; 2018-11-30- - ALLIED EARTH TECHNOLOGY 7915 SILVERTON AVENUE, SUITE 317 SAN DIEGO, CALIFORNIA 92126 TEL: (858) 586-1665 (619) 447-4747 E-MAIL: ROBERTAET@AOL.COM ~r-,... • • ._-.,.l -_,.,,,.,~,., . ~ !] ~ . ,. ' , .. ii .; .. :J DEC 12 2018 r·-· -. . ~) ===========================--================================-====-===-====== ROBERT CHAN, P.E. CT 2017-0006/RP2017-0012 GEOTECHNICAL INVESTIGATION PROPOSED FIVE-UNIT CONDOMINIUM BUILDING SITE 2569 ROOSEVELT STREET CARLSBAD, CALIFORNIA FOR 2569 ROOSEVELT LLC PROJECT NO. 17-1106ES NOVEMBER 30, 2018 - ALLIED EARTH TECHNOLOGY 7915 SILVERTON AVENUE, SUITE 317 SAN DIEGO, CALIFORNIA92126 TEL: {858) 586-1665 {619) 447-4747 e-mail: LCROBERTAET@AOL.COM =======================================================------====----=-=------ ROBERT CHAN, P.E. February 27, 2017 Revised November 30, 2018 2569 Roosevelt LLC 4040 McArthur Boulevard Newport, CA. 92107 Subject: Gentlemen: Project No. 17-1106E5 Geotechnical Investigation Proposed Five-Unit Condominium Building Site 2569 Roosevelt Street carlsbad, California In accordance with your request, we have completed the geotechnical investigation for the proposed five-unit condominium building site on subject property, more specifically referred to as being a portion of Lot No. 22 of Seaside Lands, according to Map thereof No. 1722 (APN 203- 101-35-00), 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. 17-ll0GES 2569 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Page 2 Revised 11/30/2018 This opportunity to be of servis:,e.45 · erely appreciated. Should you have any questions, please do not -~~$ita~r office. Respectfully subm· ed1// ALLIED EARTH T NOLOGY TABLE OF CONTENTS INTRODUCTION ................................................................. . DESCRIPTION OF PROJECT ................................................ . SCOPE OF WORK ................................................................ . FIELD INVESTIGATION ....................................................... .. LABORATORY TESTS ........................................................... . SITE DESCRIPTION .............................................................. . PROPOSED SITE DEVELOPMENT ..................................... .. GENERAL GEOLOGY AND SUBSURFACE SOL CONDITIONS Regional Geology ....................................................... . Site Geology and Subsurface Soil Conditions ....... . Tectonic Setting ......................................................... . GROUNDWATER ..•...••......•.•...........•.....•......•..•...•.•................••.• GEOLOGIC HAZARDS Ground Shaking ........................................................... . Surface Rupture ......................................................... . Liquefaction Potential ................................................ . Landslides ...................................................................... . FINDINGS, CONCLUSIONS AND RECOMMENDATIONS General .......................................................................... . Expansion Index of On-Site Soils ............................... . Sulfate Content of On-Site Soils ................................ .. Page No. 1 1 2 2 3 3 4 4 5 5 5 6 6 7 7 7 8 8 TABLE OF CONTENTS (Cont'nd) Grading ............................................................ . Foundation and Slab Design ........................ .. Under-Slab Vapor Retarders ...................... .. Retaining Wall Design ................................. .. Seismic Earth Pressures .............................. . Lateral Loading .............................................. . Seismic Coefficients ..................................... . Concrete Flatwork ...................................... . Surface Drainage and Maintenance ......... . Foundation Plans Review .......................... . LIMITATION AND UNIFORMITY OF CONDITIONS ... Figure No. 1-Site Location Map Figure No. 2 -Approximate Location of Exploratory Trenches Figure Now. 3 to 5, inclusive -Trench log Sheet Appendix I-General Grading and Earthwork Specifications Appendix II -Laboratory Test Results Appendix Ill-References Page No. 8 10 11 11 12 13 14 14 14 15 15 - ALLIED EARTH TECHNOLOGY 7915 SILVERTON AVENUE, SUITE 317 SAN DIEGO, CALIFORNIA 92126 TEL:(858)586-1665 (619)447-4747 E-MAIL: ROBERTAET@AOL.COM ==============================----========-=========-=-=-========--====--==--- ROBERT CHAN, P.E. INTRODUCTION February 27, 2017 Revised November 30, 2018 GEOTECHNICAL INVESTIGATION This report presents the findings and conclusions of a geotechnical investigation conducted at the site of a five-unit condominium building on subject property, located at 2569 Roosevelt Street, in the City of Carlsbad, State of California. Subject property is more specifically referred to as being a portion of Lot No. 22 of Seaside Lands, according to Map thereof No. 1722 (APN 203-101-35-00). The location of the property is shown on Figure No. 1, entitled, "Site Location Map". DESCRIPTION OF PROJECT It is our understanding that the existing older residence and detached garage on the site will be demolished to accommodate the proposed development, which will consist of a 5-unit condominium building complex. The proposed structure will consist of 2 stories of condominium space over a parking level; of wood-frame/stucco and slab-on-grade construction. ---------------------------------.---------.. Project No. 17-1106ES SCOPE OF WORK 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 The objectives of the investigation were to inspect and determine the subsurface Page 2 geotechnical conditions and certain physical engineering properties of the soils beneath the site, and to evaluate any potential adverse geotechnical 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 structures. In order to accomplish these objectives, three exploratory trenches were excavated and inspected, and representative samples of the subsurface soils were collected for laboratory testing and analysis. The 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 February 8, 2017, and involved a reconnaissance of the property and the excavation of three exploratory trenches with a tractor-mounted backhoe equipped with a 24-inch bucket. The exploratory trenches were excavated at accessible locations on the site where the Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 3 most useful information relative to subsurface geotechnical conditions may be obtained. The exploratory trenches were excavated to depths varying from 8 to 10 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 5, 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 various 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 9,642 square feet, situated on the west side of Roosevelt Street, approximately 200 feet south of Laguna Drive. The topography Project No. 17-ll0GES 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page4 of the general area may be described as relatively level; with surface drainage in a westerly direction An older residence and detached garage currently occupy the site. All existing structures and improvements will be demolished to accommodate the proposed development. The property is located in a developed area of Carlsbad. The site is bounded on the east by Roosevelt Street; and on the north, west and south by existing commercial buildings. PROPOSED SITE DEVELOPMENT Site development will consist of the construction of five-unit condominium complex. The proposed buildings will be 2 stories over a street level parking garage. The proposed structures 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. Project No. 17-1106ES 2669 Roosevelt LLC 2569 Roosevelt Street Site Geology and Subsurface Soll Conditions 02/27/17 Revised 11/30/18 Page 5 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 dense to dense brown/light brown silty fine sands. The Old Paralic Deposits were overlain by a loose residual/topsoil layer on the order of 12 to 18 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-Inglewood 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 Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 6 exploration at 10 feet; and no groundwater was encountered to a depth of 25 feet at a nearby site, approximately ½ mile to the southwest. No major groundwater related problems, either during or after construction, are anticipated. However, it should be recognized that minor 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. - Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 7 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 a possibility as a result of a significant seismic event on a regional active fault. Liquefaction Potential -In consideration of the competent formational 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 formational 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 feasible 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 -------------------------------------------- Project No. 17-1106ES 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page8 recommendations may have to be presented, depending on the actual subsurface conditions encountered during construction. 3. Site grading and earth work construction will 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 geotechnical 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 Index= 11). Sulfate Content of On-Site Soils 5. The soils encountered on the site are subject to negligible sulfate exposure (sulfate content of 20). Grading 6. It is recommended that all 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. Project No. 17-1106ES 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 9 7. Where the recommendations of this Section of the report conflict with those of Appendix I, this Section of the report takes precedence. 8. Grading should begin with the demolition of the existing structures on the property, and clearing and grubbing of the site. All debris should be hauled away and hauled away to a City-approved dump site. 9. The upper residual/topsoils on the site are loose and compressible to depths as much as 18 inches. In addition, the upper soils will be further disturbed by the demolition of the foundation of the existing structures along the front portion of the property. It is therefore recommended that the on-site soils on the property be removed to a depth of 18 inches. The bottom of the over-excavation should be inspected by our firm. Any loose or unsuitable material beneath this depth should be similarly removed. Upon approval, the bottom of the eve-excavation should be scarified to a depth of 12 inches, properly moistened, and uniformly recompacted, 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< SO); and be approved at the borrow source by our firm prior to importation. Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 10 11. The soils in the exploratory trenches were replaced without much effort in compaction. It is recommended that, during rough grading, the location of these exploratory trenches Be located. The backfill soils should then be removed and uniformly recompacted. 12. 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 01557. Foundation and Slab Design 13. 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. 14. The above safe allowable soil bearing value may be increased by one-third when considering wind and/or seismic forces. 15. The settlement of foundation, when designed and loaded as outlined above, are expected to be less than ¾ inch total and ½ inch differential over a span of 40 feet. 16. 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 Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 11 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. 17. 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 18. 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 ACl302, "Guide for Concrete Floor and Slab- Construction" and ASTM 1643, "Standard Practice for Installation of Water Vapor Retarder Used in Contact with Earth or Granular Fill Under Concrete Slabs". The above foundation and slab reinforcement recommendations are based on soil characteristics, and should be superseded by the requirements of the project architect. Retaining Wall Design 19. It is recommended that retaining walls be designed to withstand the pressure exerted by equivalent fluid weights given on the following page : Project No. 17-1106ES Backfill Surface (horizontal : vertical) 2669 Roosevelt LLC 2569 Roosevelt Street level (Active) 2: 1 " Level (Restrained) 2: 1 " 02/27/17 Revised 11/30/18 Equivalent Fluid Pressure (pd) 35 so so 65 The above values assume that the retaining walls have a granular backfill. Page 12 20. On-site soils having very low expansion potential should be used as backfill behind the retaining walls. All backfill soils are to be compacted to at least 90 percent of maximum dry density in accordance with ASTM 01557. 21. All retaining walls should be supplied with a backfill drainage system adequate to prevent 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 atleast2/3 height of the retaining wall. The subdrain should be enclosed in a geotextile 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 22. Seismic earth pressure for cantilever retaining wall can be taken as an inverted - Project No. 17-1106ES 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 13 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 walls, 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 wall. A factor-of-safety of 1.2 can be used in determining the stability of the retaining wall under seismic conditions. lateral Loading 23. 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 by floor slabs or pavements should not be included in the design for passive 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. 24. A coefficient of sliding friction of 0.35 may be used for cast-in-place 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 - Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street should be applied to dead load forces only. Seismic Coefficients 02/27/17 Revised 11/30/18 Page 14 25. The seismic design factors were determined in accordance with 2013 California Building Code, and presented as follows : Site Coordinates : Latitude = 33.1647 Longitude = -117.3517 Site Class: = C Spectral Response Acceleration At Short Periods Ss = 1.158 Spectral Response Acceleration At 1-second period Sl = 0.444 Sml = 1.158 Sds = 0.772 Sdl = 0.401 Concrete Flatwork 26. In consideration of the on-site soil conditions, it is recommended that concrete flatwork be a minimum of 3 ½ inches in thickness, and be reinforced with 6x6-Wl.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 ¼ inch weakened plane contraction joints at 5-foot intervals. Surface Drainage and Maintenance 27. 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 Project No. 17-1106ES 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 15 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. Surface drainage should have a minimum 2 percent positive drainage away from the building foundation for a minimum distance of 5 feet. Foundation Plans Review 28. It is recommended that our firm review the final foundation plans for the proposed site development to verify their compliance with our recommendations. LIMITATION 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 the entire site do not deviate substantially from those disclosed in the exploratory trenches. If any variations or undesirable conditions are encountered during grading, or if the scope of the project differs from that planned at the present time, our firm should 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 Project No. 17-1106ES 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 16 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, 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 field. 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 geotechnical consultants currently practicing in the same locality. We 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 natural processes or due to man-made actions on the subject and/or adjacent properties. In addition, changes in applicable or appropriate Project No. 17-1106E5 2669 Roosevelt LLC 2569 Roosevelt Street 02/27/17 Revised 11/30/18 Page 17 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 5, inclusive, and Appendices I, II and Ill are parts of this report. • • • • • • • • • • • • • • • • • • • • • • • • • LOCltl"Ul . NOTTO SCALE PROJECT NO. 17-1106 ES FIGURE N0.1 •••••• • •••••• • • • I'-™' ri·---··-··-··-··-··1-·---··-··---··-··-··-··-.. -··-··-··-··-··'""•""-••-··-··-··-·--··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-··-.. -··-··---, jt j i • , ,. v· 1, r , 1 .,·1 ,-~ , ,, ~ ,. ~ :· · 1 . ,. .. • ,. , : ii I ..... -:-•1-c-.---·---.···•---··•,--,-,1 ,~,,.,1.:."._1.i,-';(fi ... ,! 11 ---, ---. '~;;L>,41 t,--··· -. "',*'._.,., .. II-"l ·1 I . I I ·' I 1-1 I ·I ;\,. ' I .. I I I • i ' -~ '. f I C 11 I 11. i' I • • I I! : I ,; • I 1 t I ;j • ; I!' , I 1 " D , I ' ,' I i I ~: ., I i : !l . . . 1; .... j .. . .L . " . . . . . i1 . l : T#2 )1 ~1 ii ~ i i I [ ·: ... " l l ,f· 1.1.(11,.t••'\I> 'i .., . ..-\ '11 •.. . ·ij 1'... i . ,, . !,: I : ,. .~· .... ~~-i, • !f I . . I '"'i! I .-.!~'° I l I ' l l . ,r I "! . I I ! ::: .. I •• , ~ 1 11 i r1t I l: l·I ..... ! l' I I 1'·· l I I I I I 'I ii. l ! !1 !t. ! i .. -... ·-··-··-··-··-··---··-··-··-··--···-·--;,-·.:-.s;;-;;;..~--.....-;;---.-·--···-··-··-··-··-··-··--··-··--;;--•;-,.;,;;.-....,;;;,;;.-...;.-.·.;;,.•·--··--·•--.... ..:.;. .. ·---···..,,;.;-.·.--· •. -.• ...,;···--··-··-··-··JJ APPROXIMATE LOCATION OF EXPLORATORY TRENCHES PROJECT N0.17-1106 ES 157.00' FIGURE N0.2 NOT TOSCALE LEGEND ~ APPROXIMATE LOCATION OF EXPLORATORY TRENCH ~ 0 Q , en ~ m !:; ~ :::0 m !!l • ... FT. 0 1 2 -3 0 4 5 6 7 8 9 - Project No. 17-1106ES TRENCH LOG SHEET TRENCH NO.1 Elev. 43' msl DESCRIPTION Brown, moist, loose (Topsoils) Brown, moist, medium dense (Old Paralic Deposit Unit 6-7) Dense BOTTOM OF TRENCH (No Refusal) LEGEND SOIL TYPE SILTY FINE SAND (SM} Sil TY FINE SAND (SP) 10.1 *112.0*91.8%* 0 -Indicates representative sample ,.,. -Indicates iin-situ density test Figure No. 3 FT. ' ; 0 1 2 3 4 - s CD -. -6 7 8 I 9 10 Project No. 17-1106ES TRENCH LOG SHEET TRENCH NO. 2 Elev. 42 msl DESCRIPTION Brown, moist, loose (Topsoils) Brown, moist, medium dense (Old Paralic Deposit Unit 6-7) Dense BOTTOM OF TRENCH (No Refusal} SOIL TYPE SILTY FINE SAND (SM) SILTY FINE SAND (SM) 9.8*115.0*94.3%* Figure No. 4 FT. t i ._ 0 1 r • 2 3 4 ' ' 5 j I 6 7 I 8 l Project No. 17-1106ES TRENCH LOG SHEET TRENCH NO. 3 Elev. 42 msl DESCRIPTION Brown, damp, loose (Topsoils) Brown, moist, medium dense (Old Paralic Deposit Unit 6-7) Dense, slight cementation BOTTOM OF TRENCH (No Refusal) SOIL TYPE SILTY FINE SAND (SM SILTY FINE SAND (SM Figure No. 5 1.0 APPENDIX I GENERAL GRADING AND EARTHWORK SPECIFICATIONS General 1.1 All earthwork shall be accomplished in accordance with the Grading Ordinance of the Agency having jurisdiction: Chapter 18 and 18A, 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 Consultant'· (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 from 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 geotechrucal 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. Subsurface areas to be geotechnically observed, mapped, record elevations or tested included cleared natural growid 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 guidelines 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 fill 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 ground to receive fill, moisture condition and processing of fill and compacting fill. 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 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 infonn the 0\\ner 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 all 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 gradmg plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soils, --------------------------------------------------- APPENDIX I Page 3 2.0 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 until the conditions are rectified. Preparation of Areas to be Filled 2.1 Clearing and grubbing : vegetation, such as brush, grass. roots. and other deleterious materials shall be sufficiently remo,ed 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. Chapter 30, Article 9 and 10; 40 CRF; 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 from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a \~Titten 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 v,:ith 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 : Existing 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 ground that is not satisfactory shall be over-excavated as specified in the follov,ing section. Scarification shall continue until soils are broken do\\-n 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 geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich highly fractured or otherwise unsuitable ground shall be over- excavated to competent ground as evaluated by the Geotechnical 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 Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical 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 Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical 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 ., ? -'·- 3.3 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. 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 Geotechnical 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 \\-ithin 10 vertical feet of finished grade or ~ithin 2 feet of future utilities or underground construction. 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 importing begins so that its suitability can be determined and appropriate tests performed. 4.0 Fill Placement and Compaction 4.1 Fill 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 Dl 557). 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 frequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify 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 shall 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 ofl 00 feet and vertically less than 5 feet apart from potential test locations shall be provided. APPENDIX I Page 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 shov.n on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical 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. I 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 applicable 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 of90 percent of maximum dry density from 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. APPENDIX I Page 8 7.5 Lift thickness of trench back.fill shall not exceed those allowed in the Standard Specifications of Public Works Construction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum 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~ SURFA~~--=,) :_:-::· ;7-~ ___ ..---. --::-.. FILL OVER C UT SLOPE CUT FACE SHALL BE CONSTRUCTED PRIOR TO FILL PLACEMENT TO CUT OVER FILL SLOPE PROJECT PLAN 1 TO 1 Min. FROM TOE OF SLOPE TO APPROVED GROUND KEYING AND BENCHING DETAIL A REMOVE NSUITABLE MATERIAL ----- ----------, -- -- NATURAL GROUND REMOVE UNSUITABLE MATERIAL NATURAL GROUN°), ,,. . ...... , ,. ... CUT FACE TO BE ,,/' ,,..,," CONSTRUCTED / /" PRIOR TO Fill ~./ ~---- PLACEMENT FOR SUBDRAlN SEE STAN DARD DETAIL "C" 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 JffiED OR FLOODED IN PLACE TO FIU ALL THE ROCK VOIDS • DO NOT BURY ROCK WITHIN l O FEET OF FINISH GRADED. • WINDROW OF BURIED ROCK SHALL BE PARALLEL TO THE FINISH SLOPE FILL. FINISH GRADE -------------------- C) SECTION "AA' 0 -,ro· . ··ooo· 0 (J ;· ·~··_ . 0 • ·· .... JETTED OR FLOODED GRANULAR MATERIAL OVER SIZE ROCK DISPOSAL PROFILE ALONG WINDROW DETAIL B ALLIED EARTH TECHNOLOGY DETAIL OF CANYON SUBDRAIN TERMINAL CALTRAN CLASS II PERMEABLE OR # 2 ROCK ( 3 CU. FT /FT} WRAPPED IN FILTER FABRIC 12n Min. OVERLAP FROM THE TOP HOG RING TIED EVERY 6 FEET POSITIVE SEAL SHOULD BE PROVIDE AT THE JOINT OUTLET PIPE ( NON PERFORATED PIPE ) T-CONNfCTIO FO ' - COLLECTION PIPE TO OUTLET PIPE EXISTING / GROUND~ A " SURFACE ) ,,. /" . 7----/....;.,:-✓;--_ FILTER FABRIC (MIRAFI 140 N ~::'t'"-OR APPROVED EQUNALENT -c #2 WRAPPED IN FILTER FABRIC OR CALTRANS CLASS II PERMEABLE CANYON SUBDRAIN DETAILS ALLIED EARTH TECHNOLOGY DETAIL C 12~ OUTLET PIPES, 4" NON PERFORATED, 100' Mox. 0.C. HORIZONTAL, 30' Mox. 0 . C. VERTICAL 2' Min .• -----· 1 KEYDEPTHT l ....._ ___________ ..J r 15' Min. LOWEST BENCH ( KEY) POSITIVE SEAL SHOULD BE PROVIDE AT THE JOINT 7 5.0o/~ Min. ~ OUTLET PIPE ( NON _j PERFORATED PIPE ) - FILTER FABRIC MIRAFI 140 OR APPROVED EQUIVALENT t L T-0 ' ECilON FOR COLLECTION PIPE TO OUTLET PIPE SUBORAIN INSTALLATION-SUBORAIN COLLECTOR PIPE SHALL BE INSTALLED WITH PERFORATIONS DOWN OR UNLESS OTHERWISE DESIGNED BY THE GEOTECHNICAL CONSULTAN. OUTLET SHALL BE NON-PERFORATED PIPE. THE S UBORAIN PIPE SHALL HAVE AJ LEAST 8 PERFORATIONS UNIFORMLY SPACED PER FOOT. PERFORATION SHAU BE 1/4" TO 1/2" IF DRILLED HOLES ARE USED. All SUBDRAIN PIPES SHALL HAVE A GRADIENT AJ LEAST 2% TOWARD THE OUTLET. SUBORAIN PIPES-SUBDRAIN PIPE SHALL BEASTMO 2751, SOR 23.5 ORASTMO 1527. SCHEDULE 40, OR ASTMO 3034, SOR 23.5. SCHEDULE 40 POLYVINYL CHORIDE PLASTIC (PVC) PIPE. All OUTLET PIPE SHALL BE PlACED IN A TRENCH NO WIDER THAN TWICE THE SUBORAIN PIPE, PIE SHALL BE IN SOIL Of SE> 30 JElTED OR FLOODED IN PLACED EXCEPT FOR THE OUTSIDE 5 FEET WHICH BE NATIVE SOIL BACKFILL BUTTRESS OR REPLACEMENT SUBDRAIN DETAIL D ALLIED EARTH TECHNOLOGY ,. " I PROJECT PLAN 1 TO 1 Min. FROM TOP OF SLOPE TO OUTSIDE EDGE OF KEY OVERBURDEN OR UNSUITABLE MATERIAL FINISH SLOPE SURFACE ----EXISTING -------GROUND ______ ... .,,,..,,,./ l SURFACE_________ /,.,. ~' // ,,~' / --_,,,/ --.,,,,,,,,,. NOTE: SUBDRAIN DETAILS AND KEY WIDTH RECOMMENDATIONS TO BE PROVIDED BASED ON EXPOSED SURFACE CONDITIONS HILLSIDE STABILllY FILL DETAIL E ALLIED EARTH TECHNOLOGY -------·----- Project No. 17-1106E5 2569 Roosevelt LLC 2569 Roosevelt Street APPENDIX 11 LABORATORY TEST RESULTS -------------------------------------------- 11/30/18 1. The maximum dry density and optimum moisture content of the fill soils encountered were determined in accordance with ASTM 01557, Method A. The results of the test are presented as follows: Trench# 1 Sample #1 Depth 3.0' Soil Description Brown silty fine sand (SP) Maximum Dry Density (lbs/cu.ft.) 122.0 Optimum Moisture Content (% Dry Wt.) 11.5 2. The Expansion Index of the most clayey soils was determined in accordance with ASTM D4928-08. The results of the test are presented as follows: Trench #1 Sample #1 Depth 3.0' Soil Description Brown silty fine sand (SP) Expansion Index 11* *Considered to possess very low expansion potential • Project No. 17-1106ES 2569 RooseveltLLC 2569 Roosevelt Street APPENDIX II 11/30/18 LABORATORY TEST RESULTS (CONT'ND) -------------------------------------------- 3. The sulfate content of the soils encountered were determined in accordance with California Test No. 317. The results are presented below: Trench #1 Sample#l Depth 3.0' Soil Description Brown silty fine sand Sulfate Content (ppm) 20 Negligible • • • Project No. 17-1106ES 2569 Roosevelt LLC 2569 Roosevelt Street APPENDIX Ill REFERENCES 11/30/18 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 Frontis Studio -Site Plan, Roosevelt Apartments "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 30' x 60' Quadrangle, California Geologic Survey and U.S. Geological Survey digital map series .