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Home My WebLink AboutCDP 2016-0004; 148 TAMARACK AVENUE; GEOTECHNICAL INVESTIGATION; 2017-05-03~ -~_Jff;~PPLIED CONSULTANTS M>Vir(>()l1V()tO/ ge<>/ogy 4l Mglr>IUN'ing May 3, 2017 1941-A Friendship Drive El Cajon, CA 92020 TEL (619) 258-9000 FAX (619) 258-9004 ·€iE1Vffl1 JUN 2 4 2019 Mr. Jeff Parshalle jeff@jparch.net LAND DEVELOPMENT ENGINEERING Geotechnical Investigation for the Subject Property Located at 148 Tamarack, CarJsbad, CA 92008 Subject: Dear Mr. Parshalle: In accordance with your request we have prepared this geotechnical investigation report for the subject property located at 148 Tamarack, Carlsbad, CA 92008. The purpose of this geotechnica] investigation was to determine various parameters of the subsurface soils needed construction of the addition can begin. The proposed development is the demolition of an existing single family residence and construction of a new three story residence at the subject property. Our work consisted of geotechnical observations, subsurface exploration, soil sampling, laboratory testing, calculations and analyses, and the preparation of this report. Location of the site, relative to general topography, streets and landmarks, is shown on the attached Figure 1. GEOTECHNICAL INVESTIGATION CONCLUSIONS After reviewing the results of our geotechnical investigation Applied Consultants concludes that there are no significant geotechnical or geologic constraints that cannot be mitigated by proper planning, design, and the utilization of sound construction practices. Consequently, it is our opinion that the development of the site is feasible from a geotechnical standpoint. Prior to development the existing structures shall be removed from the site. The. upper thirty six inches of the soils within a five foot offset of the proposed r~idence footprint shall be removed and recompacted. The key shall be scarified and moisture condition to 2% over optimum moisture content. Local soils may be used as fill and compacted to greater than 90% of optimum compaction io the required grade. Design of the foundation of the property shall be based on a 2000 Pounds per Square Foot bearing capacity for a 18" wide and 18" embedded footing. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 1 of26 We appreciate this opportunity to be of service. Should you have any questions,. please call our office at (619) 258-9000. Sincerely, Bernard J. Luther, CEO 148 Tamarack Ave-Geotechnical Investigation Joshua E. Devera, PE 77618 President JED/BJL 5/3/2017 Page 2 of 26 TABLE OF CONTENTS 1.0 SITE DESCRIPTION .......................................................................................................... 4 Geographic Location ................................................................................. , ........... ; ..................... 5 Fig. 1 ............................................................................................................................................... 5 2.0 SURFACE AND GROUND WATER ................................................................................. 6 3.0 SITE GEOLOGY ................................................................................................................. 6 3.1 Geologic Literature Review and Field Findings .............................................................. 6 Geographic Location: 148 Tamarack Avenue .......................................................................... 7 Fig. 2 ............................................................................................................................................... 7 3.2 Seismic Design Recommendations .................................................................................. 8 USGS-Provided Output .............................................................................................................. 9 3.3 Liquefaction, Flooding, and Landslides ......................................................................... 10 Fig. 3 ............................................................................................................................................. 11 4.0 FIELD WORK AND SOIL SAMPLING ............................................................. , ............ 12 4-.1 Subsurface Investigation ....................................................... : ........................................ 12 4.2 Soil San1ple Analyses ..................................................................................................... 12 5.0 FINDINGS ......................................................................................................................... 13 5.1 Soils Laboratory Analyses Findings ............................................................................... 13 Table 2: Applied Consultants' Soils Analyses Results ......................................................... 13 Table 3: Calculated Soil Pressures and Load Bearing Capacities ......................................... 13 6.0 CON.CLUSIONS ............................................................................... .-................................ 13 6.1 Impact of Geologic Hazards upon Subject Property ...................................................... 13 6.2 Geotechnical Investigation Conclusions ........................................................................ 14 7.0 RECOMMENDATIONS ................................................................................................... 15 7.1 Grading ............................................................................................................................ I 5 7 .2 Foundations .................................................................................................................... 15 7 .3 Concrete Slabs On-Grade ............................................................................................... 16 7.4 Earth Retaining Structures .............................................................................................. 16 8.0 REVIEW, OBSERVATIONS, AND TESTING ............................................................... 17 FIGURES ....................................................................................................................................... 19 EXPLORATORY TEST PIT LOGS ............................................................................................. 20 SOILS LABORATORY ANALYSIS WORKSHEETS ............................................................... 21 GENERAL EARTHWORK AND GRADING ............................................................................ 22 GU ID ELIN.ES ............................................................................................................................... 22 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 3 of26 1.0 SITE DESCRIPTION The location of the property is at latitude 33° 8'53°N and longitude 117°20'41 "W. The subject property is located in a residential neighborhood of Carlsbad, California (Figure 1 ). For the purpose of this report the front of the subject property which faces Tamarack Avenue is assumed to be south. The subject property is bounded on the north, west, and east by other existing residential or multi-family units; and to the south by Tamarack Avenue. Review of the current topographic map for the site indicates that the subject property is at approximately 56 feet above average mean sea level (USGS -San Luis Rey Quadrangle, 7.5 Minutes Selies). The proposed development is the demolition of an existing single family residence and construction of a new three story residence at the subject property. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 4 of26 Gt9fuVhlc Loc1t1on 141 Tamarack Avenue, Carlsbad, CA 12001 Site Location Map 148 Tamarack Ave-Geotechnical Investigation JED/BJL S/3/2017 Page 5 of26 '\ •;.;».:,;.<.. -~ ' 1,11'1 ,' ,. , ,.,✓• .r ,,. ; ~ ,/ ,i . ~- Fig. 1 t N 2.0 SURFACE AND GROUND WATER On April 10, 2017, a representative of this firm visited the site to perform physical reconnaissance and field work at the subject property. Soil samples were taken from the proposed site to be evaluated. We hand augered two borings as part of our reconnaissance. The borings were taken within the footprint of the proposed development and were terminated at a depth of fifty four inches and thirty six inches below existing grade. No ground water was encountered during our site reconnaissance. 3.0 SITE GEOLOGY 3.1 Geologic Literature Review and Field Findings We reviewed the Geologic Map of the Oceanside 30'x60' Quadrangle, California (Kennedy & Tan, 2005) for references concerning the geologic formation underlying the subject property and surrounding areas. Review of the aforementioned geologic map indicates that the underlying geologic formation at the subject property consists of Qop6-7 Qop6 is defined as: Old Parlic deposits, Unit 6 (late to middle Pieistocene) -Mostly poorly sorted, moderately permeable, reddish-brown, interfingered strand.line, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the 22-23 m Nestor terrace. Oop7 is defined as: Old Paralic deposits, Unit 7 (late to middle Pleistocene)-Mostly poorly sorted, moderately permeable, reddish brown, interfingered strandline, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the 9-11 m Bird Rock terrace. Locally the materials encountered are: Boring#l: Topsoil from grade to three inches below grade was encountered. From three inches below grade to fifty four inches below grade a fine to coarse graded, orangish brown silty sand (SM) was encountered. Boring#2: Topsoil from grade to three inches below grade was encountered. From three inches below grade to eighteen inches below grade a fine to coarse graded, orangish dark brown silty sand (SM) was encountered. From eighteen inches below grade to thirty six inches below grade a fine to coarse graded, orangish brown silty sand (SM) was encountered. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 6 of 26 Gfoac,phlc Logtion; -APPLIED CONSULTANTS , .• , ,,_,,.., .• ,,,, 6C'tlhtl) .. ,.,.., .. ..,,._ ,,, r ... ,wcl ANIIW C.,.,_d, Cllllfon1l• 92HI Geologic Map 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 7 of26 i N Fig. 2 ---.. --.. - --.. ------ -.. .. -.. .. - 11111 .. .. Ill ------ 3.2 Seismic Design Recommendations The proposed development should be designed in accordance with seismic considerations contained in the 2013 California Building Code (2013 CBC), American Society of Civil Engineers/Structural Engineering Institute (ASCE/SEI) Standard 7-10: Minimum Design Loads for Buildings and other Structures and City of Carlsbad requirements. Based on Section 1613 of the 2013 CBC and Sections 4, 11, & 12 of the ASCE/SEI 7-10, the following parameters may be considered for design: Seismic Importance Factor (I): Occupancy Category: Site Class: Spectral Response Coefficient (Sos) Spectral Response Coefficient (Soi) Seismic Design Category (Sos -based): Seismic Design Category (801 -based): 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 8 of26 1.0 (ASCEISEI 7-10, Table 11.5-1) II (2013 CBC, Table 1604.5) D (2013 CBC, Table 1613.5.2)) 0.802g (USGSINEHRP 2003 Seismic Design Provisions) 0.462g (USGSINEHRP 2003 Seismic Design Provisions) D (2013 CBC, Table 1613.5.6(1)) D (2013 CBC, Table 1613.5.6(2)) IIUSGS Design Maps Summary Report • Report Title148 Tamarack Ave Wed May 3, 201 7 22:03:54 UTC • Building Code Reference Document ASCE 7-10 Standard (which utilizes USGS hazard data available in 2008) • Site Coordinates 33.14796°N, 117.34469°W • Site Soil Classification Site Class D -"Stiff Soil" • Risk Category VII/III USGS-Provlded Output Ss • 1.162 g S1-= 0.445 g SMs • 1.203 g SM1 -0.692 g Sos= 0.802 g S01., 0.462 g For information on bow the SS and S 1 values above have been calculated from probabilistic (risk-targeted) and deterministic ground motions in the direction of maximum horizontal response, please return to the application and select the "2009 NEHRP" building code reference document. For PGAM, T 1., CllS, and C1t1 values, please view the detailed report. Although this information is a product of the U.S. Geological Survey, we provide no warranty, expressed or implied, as to the accuracy of the data contained therein. This tool is not a substitute for technical subject-matter knowledge. 148 Tamarack Ave-Gcotechnical Investigation JED/BJL S/3/2017 Page 9 of 26 .. .. -.. ---.. .. .. -.. .. ----.. .. • .. .. .. .. -... -... • .. .. -.. .. .. .. - 3.3 Liquefaction, Flooding, and Landslides Liquefaction of cohesionless soils can be caused by strong cyclic accelerations resulting from nearby earthquakes. Research and historical data indicate that loose, granular materials saturated by a near-surface groundwater table are most susceptible to liquefaction. The soil underlying the subject property generally exhibits low cohesive properties. However, due to the topography and the absence of a ground water table the potential for soil liquefaction is low. Additionally, the City of Carlsbad Geology General Plan-Chapter 3.5: Geology, Soils and Seismicity does not indicate that the subject property is located in a liquefaction area . The elevation of the subject property is fifty six feet above sea level -potential flooding risk is considered low and the surrounding topography does not indicate that water will pond at the subject property . No visible evidence of earth movement was seen during the site inspection and field work conducted at the subject property. The soils at the subject property are known for their favorable characteristics. We feel that the potential landslide risk at the subject property is low. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 10 of26 Geographic Location 141 Tamarack Avenue, Carlsbad, C.llfomla 12001 FEMA Flood Insurance Rate Map 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 11 of 26 ZONEA i N Fig. 3 .. • .. .. -.. .. 411 -.. -.. --------.. .. .. .. ... .. - -.. -- - - 4.0 4.1 FIELD WORK AND SOIL SAMPLING Subsurface Investigation On April 10, 2017, a representative from Applied Consultants conducted the field investigation. Boring # I was augered adjacent to the existing garage at the rear of the property to a depth of fifty four inches below existing grade. Boring #2 was augered adjacent to the existing residence at the side yard of the property to a depth of thirty six inches below existing grade. A bulk soil sample was collected from 24 to 36 inches below existing grade. Boring#l: Topsoil from grade to three inches below grade was encountered. From three inches below grade to fifty four inches below grade a fine to coarse graded, orangish brown silty sand (SM) was encountered. Boring#2: Topsoil from grade to three inches below grade was encountered. From three inches below grade to eighteen inches below grade a fine to coarse graded, orangish dark brown silty sand (SM) was encountered. From eighteen inches below grade to thirty six inches below grade a fine to coarse graded, orangish brown silty sand (SM) was encountered. 4.2 Soil Sample Analyses The purpose of collecting the bulk soil sample was to determine the soil physical characteristics through laboratory testing. The soil sample was analyzed for the following: Optimum Moisture Content and Maximum Density -ASTM D 1557 Direct Normal ''Remolded" Shear Resistance Value -ASTM D3080 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 12 of 26 -.. -.. .. --- .. -.. .. --- • ,. -• .. -.. .. --.. -.. .. -- ---.. ... 5.0 FINDINGS 5.1 Soils Laboratory Analyses Findings Applied Consultants chose to analyze the sample collected near the assumed elevation of the bottom of the new footings. The following table (Table 2) is a compilation of Applied Consultants' soils analyses results from the sample collected within the proposed footprint of the new construction: Table 2: A lied Consultants' Soils Ana ses Results Opt. Max Remolded Shear Expansion Index Moist. Phi %) 10.5 2 (Ve low) E.I. -Expansion Index Pot. -Potential pcf -pounds per cubic foot psf -pounds per square foot Using the determined soil parameters and proposed footing dimensions of 18-inches wide by 18- inches deep, Applied Consultants calculated that the load bearing capacity of the underlying soils (Lamb & Whitman, 1969). The table below contains the calculated soil pressures and load bearing capacities for the site (Table 3): 6.0 6.1 Table 3: Calculated Soil Pressures and Load Bearing Capacities Sample ID Direct Normal B-1 @24"-36" Act-Active Pass -Passive CONCLUSIONS Depth {ft) 3 Pressure Act. Pass (psf) (psf) 45 350 Impact of Geologic Hazards upon Subject Property Load Bearing Capacity (pst) 2000 In Applied Consultants' professional opinion, geologic hazards of significant magnitude are not present. Based upon our field work and historical research results, Applied Consultants makes the following conclusions: • Ground Shaking is a likely hazard to the site. Seismic activity on any active and potentially active faults would cause ground movement at the subject property that will be proportional to the magnitude of seismic event. Ground movement at the subject property would be moderated by the distance from the epicenter of the seismic event. It is expected that the structure will have to endure this to some degree. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 13 of26 • .. -• .. ------• ----.. ----.. -• .. -.. .. -.. -.. --.. --- 6.2 • Liquefaction. Groundwater was not encountered at the site. Due to the geologic formation of the subject property and elevation the potential for soil liquefaction at the subject site is low. • Flooding. Given the topography of the site, the risk of flooding is considered low. • Landslide and Earth Movement is not a likely hazard to the site. The topography and geology of the subject property are not susceptible to earth movement, the risk is low for failure in landslide or earth movement. Geotechnical Investigation Conclusions After reviewing the results of our geotechnical investigation Applied Consultants concludes that there are no significant geotechnical or geologic constraints that cannot be mitigated by proper planning, design, and the utilization of sound construction practices. Consequently, it is our opinion that the development of the site is feasible from a geotechnical standpoint. Prior to development the existing structures shall be removed from the site. The upper thirty six inches of the soils within a five foot offset of the proposed residence footprint shall be removed and recompacted. The key shall be scarified and moisture condition to 2% over optimum moisture content. Local soils may be used as fill and compacted to greater than 90% of optimum compaction to the required grade. Design of the foundation of the property shall be based on a 2000 Pounds per Square Foot bearing capacity for a 18" wide and 18" embedded footing. 148 Tamarack Ave-Geotechnical lnvestigation JED/BJL 5/3/2017 Page 14 of26 -• .. ... -- -.. -.. .. .. .. -----.. - • -.. .. -.. -.. .. -.. --.. -- 7.0 RECOMMENDATIONS 7.1 Grading 7.2 a. General All earthwork should comply with the grading requirements of the City of Carlsbad, California Building Code, except where specifically superseded in this section. Prior to grading a representative of Applied Consultants should be present to discuss the current conditions of the site, grading guidelines and schedule of the earthwork to be completed . b. Grubbing/ Clearing Grading should begin with the removal of all structures and improvements as well as all vegetation. These materials should be hauled off the site to a suitable location . C. Site Preparation Prior to development the existing structures shall be removed from the site. The upper thirty six inches of the soils within a five foot offset of the proposed residence footprint shall be removed and recompacted. The key shall be scarified and moisture condition to 2% over optimum moisture content. Local soils may be used as fill and compacted to greater than 90% of optimum compaction to the required grade. d . Fill Material The materials onsite may be used as compacted fill. If it is necessary to import fill material, the material should be approved by the geotechnical consultant. All fill material must be compacted uniformly to 90% of the maximum dry density (ASTM D 1557). e. Grading Observation It is necessary for a soils engineer, or their representative, to be present and test the compaction during the basic grading operations and placement of fill material. The engineer will be able to confirm the conditions stated in this report and verify that the grading operations are in compliance with all plans and specifications. Foundations a . Dimensions and reinforcement In our opinion the foundation design for this project may be conventional spread or continuous footings. The spread footings should be embedded a minimum of 18 inches for a three-story structure and have a minimum width of 18 inches. The steel reinforcement for the foundation footings should be three #4 rebar placed near the top and bottom of the footing with a minimum of 3" of concrete covering the top and bottom 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 15 of26 ---... ... ---.. .. -.. - ---... .. .. .. .. ... .. - .. .. .. .. .. ... .. .. -.. .. .. 7.3 layers . The continuous footings should be embedded a minimum of 18 inches for a three-story structure below the lowest grade of the finished pad and must have a width of at least 18 inches. The steel reinforcement for the foundation footings should be three #4 rebar placed near the top, and bottom of the footing with a minimum of 3" of concrete covering the top and bottom layers. b . Bearing Capacity A safe soil bearing capacity of 2,000 Pounds per Square Foot may be used in the design of these foundations. Concrete Slabs On-Grade a. Floor Slab If any interior floor slabs are used for this project they should be no less than 4" (actual). For one-story or greater structures, slab reinforcement should consist of #3 rebar placed at 18'' on center. All slab reinforcement should rest on concrete chairs or a suitable substitute. b. Moisture Protection The areas covered by the interior floor slab should be covered with a 10 mil Visqueen moisture barrier. The moisture barrier should rest on finish grade and be overlain by two inches of clean sand . 7.4 Earth Retaining Structures a . Active Pressures It is recommended that structures be able to withstand an active fluid pressure of 45 pcf for unrestrained walls. The retaining structure should have a granular backfill with a level surface and adequate drainage to prevent the buildup of hydrostatic pressures. The architect should provide details for the drainage and waterproofing of the retaining structures . b . Passive Pressures Passive pressures for the soil conditions at the subject site should be 350 pounds per square foot per foot of depth. The pressure may be increased by .25 for seismic loading. The coefficient of friction for concrete against soil should be .25 for the lateral resistance . 148 Tamarack Ave~ Geotechnical Investigation JED/BJL 5/3/2017 Page 16 of26 ------.. .. ... ... .. -.. .. --,. ... • - • -• -- ----.. --.. .. 8.0 REVIEW, OBSERVATIONS, AND TESTING (a) {b) (c) The final grading plans should be provided to our office for review in order to evaluate the acceptability of the recommendations presented herein, and provide additional recommendations, as appropriate . All construction activities during grading and foundation excavations should be continuously monitored and observed by the Geotechnical Engineer and Engineering Geologist of Record . All grading and foundation excavations on-site should be observed and tested as required, by a representative of the Geotechnical Engineer and or Engineering Geologist to verify conformance with the intent of the geotechnical/geological recommendations provided herein and to evaluate the acceptability of these recommendations for the actual site conditions . CONSTRUCTION INSPECTION AND LIMITATIONS The recommendations contained within this report are based upon Applied Consultants' field investigation. The interpolated subsurface conditions should be checked during construction by a representative of Applied Consultants. We recommend that all gradihg operations be observed by a representative of this firm . The recommendations contained within this report are based upon our field study, laboratory analyses, and our understanding of the proposed construction. If any soil conditions are encountered differing from those assumed in this report, Applied Consultants should be immediately notified so that we can review the situation and make supplementary recommendations. Additionally, if the scope of proposed work changes from that described in this report, Applied Consultants should be notified . This report has been prepared in accordance with generally accepted soil and foundation engineering practices within the greater San Diego area. Professional judgments contained herein are based upon our evaluation of the technical information gathered, our understanding of the proposed work, and our general experience in the geotechnical field. Our engineering work and judgments rendered meet current professional standards. We do not guarantee the performance of the project in any respect. We do not direct the contractor's operations and we cannot be responsible for the safety of field personnel on the site; therefore, the safety of field personnel during construction is the responsibility of the contractor. The contractor shall notify the owner if he considers any of the recommended actions contained herein to be unsafe. It is a pleasure to be of service to you. Should any questions arise, please contact our office at 619-258-9000 . 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page-17 of26 .. .. -.. ---.. .. .. --------.. ---.. --- -.. -.. till -.. ---- REFERENCES 1. American Society of Civil Engineers/Structural Engineering Institute (ASCE/SEI) Standard 7-10. 2. Bearing Capacity for Shallow Foundations -T. William Lambe & Robert V. Whitman, "Soil Mechanics", John Wiley & Sons, 1969 . 3. California Building Code (CBC 2010), 2010 4. California Mines and Geology Division (DMG}, 1974, "Maximum Credible Rock Acceleration From Earthquakes in California", Roger W. Greensfelder. 5. California Department of Conservation, Division of Mines and Geology (CDMG), 1987. "CSMIP Strong-Motion Records from the Whittier, California Earthquake of 1 October, 1987", OMS Report 87-05. 6. Geologic Map of California: San Diego-El Centro, California Division of Mines and Geology, Strand R.G., 1962 7. TOPO! [Computer Software] 1997wildflower productions (www.topo.com) San Francisco, CA: ESRI 8. 2008 USGS National Seismic Hazards Maps -Fault parameters a. http://earthquake.usgs.gov/hazards/ 9. USGS Seismic Design Maps for Engineers -Buildings Pre 2009 -Java Ground Motion Parameter Calculator http://earthguake.usgs.gov/hazards/designmaps/javacatc.php 10. Geologic Map of the Oceanside 30'x60' Quadrangele, California, 2005 Kennedy & Tan 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 18 of 26 .. --.. .. -----.. -- .. --.. .. ... .. -- .. .. • --.. -.. .. .. .. - FIGURES 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 19 of26 -APPLIED CONSULTANTS --·-Borings Location 148 TAMARACK AVE, CARLSBAD, CALIFORNIA 92008 Date : 4/12/17 Drawn by: JLVG -.. -----.. -.. -.. -------------------------- EXPLORATORY TEST PIT LOGS 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 20 of 26 .. .. • .. Date: 4/10/2017 Project Name: 148 TAMARACK AYE Address: 148 TAMARACK A VE CARLSBAD, CA Logged By: _ _.JL-....V..,,.G __________ _ ReviewedBy:__..,ffi.,..p...__ __________ _ Location: WESTERN PORTION I BEHIND (E} GARAGE Footing Thickness (in.): __._N .... A.__ ____ _ Boring /fest pit ID: B-1 Depth (Inches) Soil Description Depth to Water (ft): _ __.,...._ ____ _ Caving: _____ ......... .....,..,___ De ofFootin : 1----,-S_am~p_le"""T""_-;Discrete Bulk Lithology & Footing Details ype ID Sample Sample MC% Interval Interval e--1-------------+--+----11-------1---+----11----------+---rt Topsoil 6 12 18 24 3 36 42 48 54 60 66 Silty Sand (SM): fine to coarse graded, orangish brown silty sand (SM) B-1 5.6% END OF BORING@ 54" BORING LOG: BORING 1 148 TAMARACK AVE, CARLSBAD, CA DATE: 4/10/2017 Drawn By: JLVG 6 12 18 24 30 36 42 48 54 60 66 72 .. ------.. .. -.. .. ----- ... .. .. .. .. Project Name: 14~ I.AMARACK A VE Date: 4/10/2017 Address: 148 TAMARACK A VE Logged.By: JLVG CARLSBAD, CA Reviewed By: JED Location: WESTERN SIDE/ ADJACENT TO {El FTG Footing Thickness (in.): NA Excavation Method· AUGER Depth to Water(ft): NA Boring rrest pit ID: B-2 Samf le T~e: BULK Caving: NQNE Tota Der: <ft): 1.0 Denth ofFootimz: NA Depth Sample Discrete Bulk Lithology & Footing (Inches) Soil Description Sample Sample !Type Details ID MC% Interval Interval Grade Topsoil ---------61----Silty Sand {SM): fine to coarse --graded, orangish dark brown silty 12 -sand (SM) --18 -----------24 --Silty Sand (SM): fine to coarse I graded, orangish brown silty sand -(SM) 30 -B-2 6.8% --·//'-',, 36 ~~% -END OF BORING@36" -42 ---48 ---54 ---60 ----66 ---- 72 -- -APPLIED BORING LOG: BORING 2 DATE: 4/10/2017 148 TAMARACK A VE, Drawn By: JLVG ~W'Nil~ CARLSBAD, CA i .c: u .5 '-' -- 6- -- 12- -- 18- - - 24- -- 30- -- 36- -- 42- -- 48--- 54- - - 60- -- 66- -- 72- ... • .. ... --.. .. .. .. ... • -.. -------.. .. .. ... .. .. -.. .. .. -.. .. • .. ◄ SOILS LABO RA TORY ANALYSIS WORKSHEETS 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 21 of 26 .. --------- • .. ... --... .. .. • ... .. .. -... ... • -• -.. ... .. --.. GENERAL EARTHWORK AND GRADING GUIDELINES 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 22 of26 -.. -... ----.. -.. .. .. .. -.. .. .. .. .. -.. .. .. - - .. .. ... .. .. GENERAL EARTHWORK AND GRADING GUIDELINES I. EARTHWORK OBSERVATION AND TESTING Prior to commencement of grading, a qualified geotechnical consultant should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations of the geotechnical report and these specifications. The consultant is to provide adequate testing and observation so that he may determine that the work was accomplished as specified. It should be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes so that the consultant may schedule his personnel accordingly. The contractor is to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications, and the approved grading plans. If in the opinion of the consultant, unsatisfactory conditions are resulting in a quality of work less than required in these specifications, the consultant may reject the work and recommend that construction be stopped until the conditions are rectified . Maximum dry density tests used to determine the degree of compaction should be perfonned in accordance with the American Society for Testing and Materials Test Method ASTM: D 1557-82 . II . PREPARATION OF AREAS TO BE FILLED 1. Clearing and Grubbing: All brush, vegetation, and debris shall be removed and properly disposed of. The Geotechnical Consultant shall evaluate the extent of removal of these items depending on site conditions. Fill material shall not contain more than I percent of organic material by volume. No fill should contain more than 5 percent organic matter. No fill shall contain hazardous materials or asphalt pavement. If asphalt pavement is removed, it should be disposed of at an appropriate location. Concrete fragments which are free of reinforcing steel may be placed in the fills . 2. Processing: the existing ground which is evaluated to be satisfactory for support of fill shall be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory shall be over-excavated as specified in the following section. Scarification shall continue until the soils are broken down and free of large clay lumps or clods and until the working surface is reasonably uniform and free of uneven features which would inhibit unifonn compaction. 3. Over excavation: Soft, dry, spongy, or otherwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, shall be over- excavated down to finn ground as approved by the consultant. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 23 of 26 -.. ... ----.. ... .. • • .. .. -.. .. - .. • -... • .. tll .. • .. .. 4. Moisture Conditioning: Over-excavated and processed soils shall be watered, dried-back, blended, and/or mixed, as necessary to attain a uniform moisture content approximately 2 percent over optimum. 5. Re-compaction: Over-excavated and processed soils which have been properly mixed and moisture-conditioned shall be compacted to a minimum relative compaction of 90 percent according to ASTM: D1557-82. 6. Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be benched. The lowest bench shall be: a minimum of 15 feet wide, at least 2 feet deep with a minimum 2% slope into the fill bank for horizontal stability, expose firm materials, and be approved by the consultant. Other benches shall excavate into firm material for a minimum width of 4 feet. Ground sloping flatter than 5:1 shall be benched or otherwise over-excavated when considered necessary by the consultant. 7. Approval: All areas to receive fill, including processed areas, removal areas, and toe-of-fill benches shall be approved by the consultant prior to fill placement. III. FILL MATERIAL 1. General: Material to be placed as fill shall be free of organic matter and other deleterious substances, and shall be approved by the consultant. Soils of poor gradation, expansion, or strength characteristics shall be placed in areas designated by the consultant or mixed with other soils until suitable to serve as satisfactory fill material . 2. Oversize: Oversize material defined as rock, or other irreducible material, with a maximum dimension of greater than 12 inches, shall not be buried or placed in fill unless the location, materials, and disposal methods are specifically approved by the consultant. Oversize disposal operations shall be such that nesting of oversized material does not occur, and such that the oversized material is completed surrounded by compacted or densified fill. Oversize material shall not be placed within the range of future utilities or underground construction, unless specifically approved by the consultant. 3. Import: If import fill is necessary for grading, the import material shall be approved by the geotechnical consultant. IV. FILL PLACEMENT AND COMPACTION 1. Fill Lifts: Approved fill material shall be placed in areas prepared to receive fill in near~horizontal layers not exceeding 6 to 8 inches in compacted thickness. The consultant may approve thicker lifts if testing indicates that the grading procedures are such that adequate compaction is being achieved with lifts of greater thickness. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to attain uniformity of material and moisture in each layer. 2. Fill Moisture: Fill layers at a moisture content less than optimum shall be watered and mixed, and wet fill layers shall be aerated by scarification or blended with drier materials. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/312017 Page 24 of26 .. .. -.. .. -.. .. .. .. .. .. .. -.. .. .. .. --.. -.. • .. .. -.. • ---.. .. -- Moisture conditioning and mixing of fill layers shall continue until the fill material is at a uniform moisture content at or near two percent over optimum . 3. Compaction of Fill: After each layer has been evenly spread, moisture conditioned and mixed, it shall be uniformly compacted to not less than 90 percent of maximum dry density in accordance with ASTM: D1557-82. Compaction equipment shall be adequately sized and either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree of compaction . 4. Fill Slopes: Compacting of slopes shall be accomplished, in addition to normal compaction procedures, by backrolling of slopes with sheepsfoot rollers at frequent intervals of 2 to 3 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the slope out to the slope face shall be at least 90 percent. 5. Compaction Testing: Field tests to check the fill moisture and degree of compaction will be performed by the consultant. The location and frequency of tests shall be at the consultant's discretion. In general, the tests shall be taken at an interval not exceeding 2 feet in vertical rise and/or every 1000 cubic yards of embankment. V. SUBDRAIN INSTALLATION Subdrain systems, if required, shall be installed in approved ground to conform to the approximate alignment and details shown on the plans or shown herein. The subdrain location or materials should not be changed or modified without the approval of the consultant. The consultant, however, may recommend and upon approval, direct changes in subdrain line, grade or material. All subdrains shall be surveyed for line and grade after installation and sufficient time allowed for surveys, prior to commencement of filling over the subdrains. VI. EXCAVATIONS Excavations and cut slopes shall be examined during grading. If directed by the consultant, further excavation or overexcavation and refilling of cut areas shall be performed, and/or remedial grading of cut slopes performed. Where fill-over-cut slopes are to be graded, unless otherwise approved, the cut portion of the slope shall be made and approved by the consultant prior to placement of the fill portion of the slope. Excavations may require the consultant to produce an alternate sloping plan if the excavation VII. TRENCH BACKFILL 1. The Contractor shall follow all OSHA and CAUOSHA requirements for maintaining safety of trench excavations . 2. The bedding and backfill of utility trenches should be done with the applicable provisions of Standard Specifications of Public Works Construction. Bedding material should have a sand equivalent of (SE >30). Bedding should be placed 1 foot above the top of pipe. All backfill should be compacted to 90 percent from 1 foot above the pipe to the surface. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 25 of26 .. ----- • .. - -.. -.. --.. .. .. ---... -.. .. -.. • --- .. -.. 3. The geotechnical consultant should test the trench backfill for relative compaction. At least one test should be performed for every 300 feet of trench and every two feet of trench fill. 4. The lift thickness of the trench backfill shall not exceed what is allowed in the Specifications of Public Works Construction unless the contractor can demonstrate that the fill can be compacted by an alternative means to the minimum relative compaction . 5. All work associated with trenches, excavations and shoring must conform to the local regulatory requirements, State of California Division of Industrial Safety Codes, and Federal OSHA requirements. VIII. FOUNDATIONS NEAR TOP OF SLOPES Where foundations, footings, walls and other similar proposed structures are to be located seven feet and further away from the top of slopes, standard design may take place in conformance with the recommended soil bearing value. In situations where foundations, footings, walls, et cetera, are located closer than seven feet from the top of slope they shall be deepened so that the bottom edge of the footing is 7 feet horizontally from daylight in the slope. 148 Tamarack Ave-Geotechnical Investigation JED/BJL 5/3/2017 Page 26 of26