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Home My WebLink AboutCDP 2016-0004; 148 TAMARACK AVENUE; PLAN REVIEW; 2019-06-04Bernard J. Luther,RCE 63653, CEG 1356 CEO ç.OFE C63653 (PA NO CEG1356 CIVI \Y CA CA ir APPLIED 1941-A Friendship Drive CONSULTANTS enwra,menta/ Qeo!ogj/ & El Cajon, CA 92020 June 4, 2019 Thi, (619) 258-9000 FAX (619) 258-9004 www.applied-consultants.com Mr. Jeff Parshalle jeff@jparch.net Subject: Plans review letter for the Subject Property located at 148 Tamarack, Carlsbad, CA 92008 Dear Mr. Parshalle: In accordance with your request we have reviewed the grading plans prepared by bHa, Inc DWG 517-7A, and the structural plans prepared by Mike Suprenant and Associates dated August 11, 2017 (revised 6/4/19) for the new single family residence with detached garage for the aforementioned address. Specifically, we have reviewed sheets Sheet 1 and Sheet 2 of the grading plans and sheets S-I, S-2, S-3, SD-1 and SD-6 of the structural plans. The purpose of our review was to determine if the recommendations from our geotechnical investigation report for the subject property 148 Tamarack, Carlsbad, CA 92008 were incorporated into the construction documents. We certify that our recommendations for the subject property 148 Tamarack, Carlsbad, CA 92008 were incorporated into the construction documents. We appreciate this opportunity to be of service. Should you have any questions, please call our office at (619) 258-9000. Sincerely. 148 Tamarack Ave —Plans Review JLVG/BJL 6/4/19 Page I oil 1941-A Friendship Drive El Cajon, CA 92020 _________ 71L (61 258-9000 APPLIED FAX(619) 258-9004 CONSULTANTS June 3, 2019 www.app!ied-consultants.com environmental geology & engineering Mr. Jeff Parshalle jeffjparch.net Subject: Response to Third-Party Geotechnical Review (First Review) dated April 24, 2019 for the Subject Property located at 148 Tamarack, Carlsbad, CA 92008 Dear Mr. Parshalle: In accordance with your request, we have provided this Addendum Geotechnical report in response to the City Carlsbad, Third-Party Geotechnical Review (First Review) dated April 24, 2019 by Herrington Engineering, Inc for the Subject Property located at 148 Tamarack, Carlsbad, CA 92008 The following are our responses to the Third-Party Geotechnical Review (First Review): Issue #1 Due to the age of the "Geotechnical Investigation..." (Reference 1), the Consultant should provide an updated geotechnical report addressing the plans, and provide updated grading and foundation recommendations consistent with the 201 California Building Code, as necessary. See Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - Grading and foundation recommendations have been revised to be consistent with the 2016 California Building Code Issue #2 The Consultant should review the project grading and foundation plans, provide any additional geotechnical recommendations considered necessary, and confirm that the plans have been prepared in accordance with the geotechnical recommendations provided in the referenced reports. See Plans review letter for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - A plan review letter has been included as part of this response. 148 Tamarack Ave - Third Patty Geology review (1st review) JLVG/BJL 6/3/2019 Page 1 of 4 Issue #3 The Consultant should provide an updated geotechnical map/plot plan utilizing the latest grading plan for the project to clearly show (at a minimum) a) existing site topography, b) proposed structures/improvements, c) proposed finished grades d) locations of the subsurface exploration, e) geologic contacts, and f) remedial grading limits. See Figure A - Geologic / Geotechnical Map of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - We have provided and updated geotechnical map utilizing the latest grading plan and showing minimum requirements accordingly. Issue #4 The Consultant should provide a detailed description of proposed site grading, structures/improvements, foundation type etc. See page 1, and pages 17 to 20 of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - Detail description of proposed site grading, structures/improvements and foundation type has been provided accordingly. Issue #5 The Consultant should discuss regional geologic conditions, geologic structure, and faulting. See pages 6 to 10 of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - Discussion of the regional geologic conditions, geologic structure and faulting has been provided accordingly. Issues #6 & 7 The Consultant should identify the geologic units encountered on the boring logs. The "Borings Location" plan depicts two boring number B-I's. Please revise or clarify. See Exploratory Boring Logs and Figure A: Geologic / Geotechnical map of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - The geologic unit encountered has been noted on the boring logs and the Geotechnical map has been revised to depict correct boring numbers. 148 Tamarack Ave - Third Party Geology review (l's review) JLVG/BJL 6/3/2019 Page 2 of 4 Issue #8 The Consultant should provide the ASTM standards used for the laboratory testing. See Section 4.2 Soil Sample Analyses (page 14) of the .Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - ASTM Standards used for the laboratory testing have been provided accordingly. Issue #9 The Consultant should provide a statement regarding the impact of the proposed grading and construction on adjacent properties and improvements. See Section 3.3 Geologic Hazards (page 11) of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - Statement regarding impact of the proposed grading and construction on adjacent properties has been provided accordingly. Issue #10 to 12 The Consultant should clarify if the remedial grading recommendations apply to the detached garage structure. The Consultant should provide remedial grading recommendations for proposed driveway/hardsoape areas. The Consultant should provide a description of what are considered approved foundation embedment materials. See pages 1 and 17 to 20 of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - Clarification on remedial grading and approved embedment materials has been provided accordingly. Issue #13 The Consultant should address expected total and differential settlement due to grading and foundation loads. See Section 3.3 Geologic Hazards (page 11) of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - Expected total and differential settlement due to grading and foundation loads has been provided accordingly. 148 Tamarack Ave - Third Party Geology review (1st review) JLVG/BJL 6/3/2019 Page 3 of 4 Issues #14& 15 The Consultant should provide hardscape recommendations (thickness, reinforcement, joints, etc.). The Consultant should specify the sulfate exposure category (ACI 318) based on soluble sulfate testing and provide recommendations for sulfate resistant concrete, if necessary, or default to a severe exposure category, if testing is not available. See Section 7.0 Recommendations (pages 19 & 20) of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 -, Hardscape recommendations and sulfate exposure category have been provided accordingly. Issue #16 The Consultant should provide a list of recommended observation and testing during site grading and construction. See Section 7.1 Grading / Observation and testing (page 18) of the Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 - A list of recommended observation and testing during site grading and construction has been provided accordingly. We appreciate this opportunity to be of service. Should you have any questions, please call our office at (619) 258-9000. Bernard J. Luth, RCE 63653, CEG 1356 CEO 148 Tamarack Ave - Third Party Geology review (1's review) JLVGIBJL 6/3/2019 Page 4 of 4 I .1941-A. Friendship. Drive. El Cajon, GA 92020 TEL (6/9) 258-9000 - _---'i'JJED FAX (619) 258-9004 June 3, 20.19. wwwappliedconsultants.corn CONSULTANTS geotechnical & forensic engineering :uii r Ill 'T11E IIJ I . Mr; Jeff Parshalle JUN 0 4 2019 I jeff@jparch.net . LAND DEVELOPMENT ENGINEERING Subject Updated Geotechnical Investigation for the Subject Property Located at 148 I . Tamarack, Carlsbad, CA 92008 Dear Mr. Parshalle: I 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 I geotechnical investigation was to determine various parameters of the subsurface soils needed construction of the addition can begin. I The proposed development is the demolition of an existing single family residence and construction of a new two story residence and a new detached two story structure for a garage with a dwelling unit above The residential units will be designed with a shallow foundation I system. The proposed project will include a new concrete driveway and pervious concrete payers Remedial grading is proposed for the soils that will underlie the new two residential I .structures and the area of the proposed concrete driveway. 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 I 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 I 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 remedial grading. shall consist of the removal and recompaction of the upper thirty six inches of the I site soils within a five foot offset of the proposed development footprint. 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. Over-excavation I near existing footings shall be maintained to a 1:1 slope from bottom of footing to bottom of excavation. I P 148 Tamarack Ave- Updated Geotechnical Investigation JLVGLBJL 6/3/2019 Page 1 of 29 I Prior to preparation and placement of the proposed footings the Geotechnical consultant shall evaluate the bottom of the footings trenches to be satisfactory to achieve the design bearing capacity. 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 firm ground as approved by the consultant. Approved foundation embedment materials shall consists of local fill soils compacted to greater than 90% of optimum compaction.: Design of a shallow foundation system of the proposed two-story structures shall be based on a 2,000 psf allowable bearing capacity for recompacted soils. We appreciate this opportunity to be of service. Should you have any questions, please call our office at (619) 258-9000. Sincerely, 7 / EIT 164277 'Bernard. J. Luther, RCE 63653, CEG .1356 effer . . CEO Ss, SSION44 0, LIF I I I I I I I I I I I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 . : Page 2 of 29 I I TABLE OF CONTENTS 1.0 SITE DESCRIPTION ................................................ .. ........... ...... .. ........ .. ............... ..................4 Fig. 1 Site Location .......................................................................................................................... 5 20 SURFACE AND GROUND WATER 6 3.0 SITE GEOLOGY ................................................... . ........... .6 3.1 Geologic Literature Review and Field Findings .• ................................................................ Fig. 2 Regional Geology.................................................................................... .... .. .. 8 Fig. 3 Geologic Map .................................................................................................................................9 3.2 Tectonic Setting .............................................................. . .................................................... .10 3.3 Seismic Design Recommendations ....................10 3.3 Geologic Hazards ........................................................................................................................ Fig 4 Liquefaction Hazard Map 12 Fig. 5 FEMA Flood Rate Insurance Map.................. 1. 40 FIELD WORK AND SOIL SAMPLING 14 4.1 Subsurface Investigation ........................................................................................................14 4.2 Soil Sample Analyses ...... ....................................... .14 5.0 FINDINGS .............. .... ......... ...................... .15 5.1 Soils Laboratory Analyses Findings..................................................... 15 Table 1: Applied Consultants' Soils Analyses Results.............. ... Table 2: Calculated Soil Pressures and Load Bearing Capacities ............................................ .15 6.0 CONCLUSIONS.................................................................. .......................................................16 6.1 Impact of Geologic Hazards upon Subject Pro perty .......... ................... ......... . .................. 16 I 6.2 Geotechmcal Investigation Conclusions 16 7.0 RECOMMENDATIONS .............................................. .. ................................................... 17 I 7.1 7.2 Grading...........................................................................................................................17 Shallow Foundations ...................................................................................................... 18 7.3 Concrete Slabs On-Grade ............................................................................................... 19 I 7.4 7.5. Sulfate exposure category ................................................................................................19 .20 Earth Retaining Structures .................................................................... ............. 7.6 Minimum Driveway Pavement Recommendations ..... ....................... ............................. 20 I 8.0 REVIEW, OBSERVATIONS, AND TESTING ...............................................................21 FIGURES......................................................................... . ............................................................ 23 EXPLORATORY TEST PIT LOGS .............................................................................................24 • GENERAL EARTHWORK AND GRADING GUIDELINES ..................................................... 25 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 3 of 29 1.0 SITE DESCRIPTION The location of the property is at latitude 330 8'53"N and longitude 11.7'2041"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 Series). The proposed development is the demolition of an existig.single family residence and construction of a new two story residence and anew detached two story structure for a garage with a dwelling unit above The residential units will be designed with a shallow foundation system The proposed project will include a new concrete driveway and pervious concrete pavers Remedial grading is proposed for the soils that will underlie the new two residential structures and the area of the proposed concrete driveway. 148 Tamarack Ave- Updated Geotecimical Investigation JLVG/BJL 6/3/2019 Page 4 of 29 .4 iwT t - ArcW ç - -. ,• ' . ' CARLSBAD d. .- . SUBJECT PROPERTY AIL A L11 7 ,t•' \\ \ -, Ln . •. - . .. - . -- .4. V p- . -: lie .' I '..•\tp - H -: ....... : A. Geographic Location 148 Tamarack Avenue, Carlsbad, CA 92008 N --APPLIED Site Location Map CONSULTANTS Fig. in IrvIAm. sill! ecu/u-i .4 lavA. iflfl% 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 5 of 29 2.6 SURFACE AND GROUND WATER On April 10, 2017, a representative of this firm visited the site to perform physical I 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 I 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 Reaional Geolov: We reviewed the General Geologic. Map of California (Guitierrez, Bryant, Salcedp & Wills, 2010) for references concerning the regional 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 Old alluvium, lake, playa and terrace deposits (Qoa). The Old alluvium, lake, playa and terrace deposits are commonly defined as Fluvial sediments deposited on canyon floors Consists of moderately well consolidated, poorly sorted, permeable, commonly slightly dissected gravel, sand, silt, and clay-bearing alluvium. Local Geolo I We reviewed the Geologic Map of the Oceanside 30'x60' Quadrangle, California (Kennedy & Tan, 2005) for references concerning the local geologic formation underlying the subject property and surrounding areas. I Review of the aforementioned geologic map indicates that the underlying geologic formation at the subject property consists of Qop6-7: I Qop6 is defined as: Old Panic deposits, Unit 6 (late to middle Pleistocene) - Mostly poorly sorted, moderately permeable, reddish-brown, interfingered strandlirie, beach, estuarine and I coliuvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the 22-23 in Nestor terrace, I 0op7 is defined as: Old Paralic deposits, Unit 7 (late to middle: Pleistocene)- Mostly poorly sorted, moderately permeable, reddish brown, mterflngered strandime, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the I 9-11 m Bird Rock terrace. I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 - Page 6 of 29 Locally the materials encountered are: Boring #1: 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 Iinches below grade a fine to coarse graded, orangish brown. silty sand (SM) was encountered. I I I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 7 of 29 I SUBJECT E PROPERTY MzV E 148 Tamarack Avenue, Carlsbad, California 92008 K E Geographic Location APPLIED CONSULTANTS an ,ronn,qga! I. ....log. [--~0(11 Oer JtMu1i. take, paya. and Wnaw øep%13 Regional Geology Geologic Map of California (2010) Fig. 2 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 8 of 29 Escondido Jun I Geographic Location: 148 Tamarack Avenue Carlsbad, California 92008 N ;;7 Old paralic deposits, Unit 7 (late to inlddk Pleistocene)—Mostly poorly sorted, moderately permeable, reddish-brown. interfingered strandline, beach, ertuaririe and colluvial deposits composed of siltstone. sandstone and conglomerate. These deposits rest on the 9-11 m Bird Rock terrace (Fig. 3) Qop Old paralic deposits, Unit 6 (late to middle Pleistocene)—Mostly poorly sorted, moderately permeabe, reddish-brown, interfingered strandline, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the 22-23 it Nestw terrace (Fig. 3) LAPPLIED Geologic Map Fig. 3 CONSULTANTS Oceanside Quadrangle 148 Tamarack Ave- Updated Geotechnical Investigation ILVG/BJL 6/3/2019 Page 9 of 29 ( ( 3.2 Tectonic Setting Southern California, including San Diego and surrounding areas, is located in an area of late Tertiary to Quaternary-aged fault zones (Kennedy 1975) which strike conservatively to the northwest Some of these fault zones are known to be active according to the California Division of Mines and Geology. "Active" faults are ones which have had faulting activity, within the Holocene Epoch, or the last 11,000 years (California Division of Mines and Geology). The highest risks originate from the Elsinore fault zone, the Rose Canyon fault zone, and the offshore faults, each with the potential to cause moderate to large earthquakes that would cause ground shaking in Carlsbad and the subject property... Based upon magnitude of the earthquake event and distance from the subject property; an earthquake on any of the above mentioned faults would cause slight to severe shaking at the subject property. I .3 Seismic Design Recommendations The proposed development shall be designed in accordance with seismic considerations I contained in the 2016 California Building Code (2016 CRC), American Society of Civil Engineers (ASCE) Standard 7-10: Minimum Design Loads for Buildings and other Structures and City of Carlsbad requirements. Based on the 2016 CBC and ASCE 7-10, the following parameters may be considered for design: I Seismic Importance Factor (I): 1.0 (ASCE 7-16) Occupancy Category: II (2016 CBC) Site Class: D (2016 CBC) I Spectral Response Coefficient (SDs) 0.802g (ASCE 7 Hazard Tool Online) Spectral Response Coefficient (SD!) 0.462g (ASCE 7 Hazard Tool Online) Seismic Design Category D (2016 CBC) I I I I I 148 Tamarack Ave Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 10 of 29 I I I 3.3 Geologic Hazards 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 64 Geologic and Seismic Hazards 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 Settlement resulting from the grading and anticipated foundation loads should be minimal provided that the recommendations included in this report are considered in design and construction The total settlement is estimated to be less than one inch when using the recommended bearing pressures and differential settlement is estimated to. be one-half of the total settlement. Based upon the relatively low difference in elevation between the subject property and adjacent properties we feel that the proposed grading and construction as recommended will not measurably destabilize neighboring properties nor induce the settlement o. adjacent structures and improvements. 148 Tamarack Ave- Updated Geotechnical Investigation JLVGIBJL 6/3/2019 Page ii of 29 148 Tamarack Avenue, Carlsbad, California 92008 Potential Liquefaction Riverwash Tidal flats Tujunga sand, 0 to 5 percent slopes V/1 Other Hazard Liquefaction Hazards Map APPL1ED City of Carlsbad General Plan CONSULTANTS Geologic and Seismic Hazards 148 'Thmarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 12 of 29 Fig. 4 Geographic Location 2000000 FT CHINQUAPIN AVE A GIJA HEDIONDA LA GOON '- ZONE A ZONEAE (EL 11) 148 Tamarack Avenue, Carlsbad, California 92008 N APPLIED CONSULTANTS , ctIot 4 •qafl,.., FEMA Flood Insurance Rate Map Fig. 5 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2319 Page 13 & 29 I 4.0 FIELD WORK AND SOIL SAMPLING I 4.1 Subsurface Investigation I On April 10, 2017, a representative from Applied Consultants conducted the field investigation. Boring #1 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 I 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. I Boring #1: from grade to three inches below grade. was encountered. I Topsoil From three inches below grade to fifty four inches below grade a fine to coarse graded, I orangish brown silty sand (SM) was encountered. Boring #2: I Topsoil from grade to three inches below grade was encountered. I orangish From three inches below grade to eighteen inches below grade a fine to coarse graded, dark brown silty sand (SM) was encountered. I graded, From eighteen inches below grade to thirty six inches below grade a fine to coarse brown orangish silty sand (SM) was encountered. I 4.2 Soil Sample Analyses I 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: I . Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates - ASTM C136/Cl36M Optimum Moisture Content and Maximum Density - ASTM D 155 I Standard Test Method for Expansion Index of Soils - ASTM D4829 Direct Normal "Remolded" Shear Resistance Value - ASTM D3080 I I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 14 of 29 I 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 1) is a compilation of Applied Consultants' soils analyses results from the sample collected within the proposed footprint of the new construction: Table 1: Annlied Consultants' Soils Analyses Results Sample ID Opt. Moist. Max Density Remolded Shear Expansion Index Cohesion Phi (%) (pcf) (angle) (psf) B-I @ 24"- 36" 10.5 121 32 50 2 (Very low) E.I. - Expansion Index pcf- pounds per cubic foot Pot. - Potential psf, - pounds per square foot 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 2): Table 2: Calculated Soil Pressures and Load Bearing Capacities Sample ID Direct Normal Depth Pressure Load Bearing Capacity Act. Pass (ft) (psf) (psf) (psf) B-1 @ 24"-36" 3 45 350 2,000 Act - Active Pass - Passive 148 Tamarack Ave- Updated Geotechiica1 Investigation JLVG/BJL 6/3/2019 Page 15 of 29 6.0 CONCLUSIONS 6.1 Impact of Geologic Hazards upon Subject: Property 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 I 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 I expected that the structure will have to endure this to some degree. Liquefaction. Groundwater was not encountered at the site... Due to the geologic I formation of the subject property and elevation the potential for soil liquefaction at the subject site is low. I • Flooding. Given the topography of the site, the risk of flooding is considered low. I . 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 I 6.2 Geotechnical Investigation Conclusions I 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 I planning, design, and the utilization of sound construction practices. Consequently, it is: .0W opinion that the development of the site is feasible from a geotechnical standpoint. I Prior to development the existing structures shall be removed from the site. The remedial grading shall consist of the removal and recompaction of the upper thirty six inches of the site soils within a five foot offset of the proposed development footprint., The key shall be scarified and I 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. Over-excavation near existing footings shall be maintained to a 1:1 slope from bottom of footing to bottom of I excavation. Prior to preparation and placement of the proposed footings the Geotechnical consultant shall I evaluate the bottom of the footings trenches to be satisfactory to achieve the design bearing capacity. 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 I firm ground as approved by the consultant Approved foundation embedment materials shall consists of local fill soils compacted to greater than 90% of optimum compaction I 148 Tamarack Ave- Updated Geotechnical Investigation JLVGIBJL 6/3/2019 Page 16 of 29 Design of a shallow foundation system of the proposed two-story structures shall be based on a. 2,000 psf allowable bearing capacity for recompacted soils. 7.0 RECOMMENDATIONS 7.1 Grading General All earthwork should comply with the grading requirements of the City of Carlsbad, 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. 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 remedial• grading shall consist of the removal and recompaction of the upper thirty six inches of the site soils within a five foot offset of the proposed development footprint. 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. Over-excavation near existing footings shall be maintained to a 1:1 slope from bottom of footing to bottom of excavation. Prior to preparation and placement of the proposed footings the Geotechnical consultant shall evaluate the bottom of the footings trenches to be satisfactory to achieve the design bearing capacity. 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 firm ground as approved by the consultant. Approved foundation embedment materials shall consists of local fill soils compacted to greater than 90% of optimum compaction. d. Fill Material I 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 Dl 557). I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 17 of 29 I I e. Grading Observation It is necessary for a soils engineer, or their representative, to be present and test the I 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 I grading operations are in compliance with all plans and specifications. e. Observation and testing I 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 I grading operations are in compliance with all plans and specifications. The Consultant shall provide the following observation and testing during grading and I construction: . Observation of subsurface conditions Observe the site soil, conditions through I several excavation trenches to check subsurface conditions and soil properties in comparison to the approved geotechnical reports. I . Laboratory testing to check soil conditions and strength parameters for design purposes. Tests included maximum 'dry density, in-place moisture and density. I . Observation of engineered fill placement and compaction per Section IV of the attached General Earthwork and Grading Guidelines. Field density testing for I compaction of the engineered fill in accordance with ASTM D15 56 or ASTM D6938 methods. I . Inspection of bottom of the footings trenches to be satisfactory to achieve the design bearing capacity. I 7.2 Shallow Foundations I a. General Where foundations are to be located seven feet and further away from the top of slopes, I standard design may take place in conformance with the recommended soil bearing value. In situations where foundations, footings, walls, etcetera, 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 I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 18. of 29 H b. Dimensions and reinforcement: In our opinion the foundation design for this project may be conventional spread and/or continuous footings The spread footings shall be embedded a minimum of 12 inches for a one-story structure and have a minimum width of 12 inches The spread footings shall be embedded a minimum of 18 inches for a two-story structure and have a minimum width of 15 inches The steel reinforcement for the spread footings shall consist of a minimum of two #4 rebar placed near the top and bottom of the footing with a minimum of 3" of concrete covering the top and bottom layers. The continuous footings shall be embedded a minimum of 12 inches for a, one story structure below the lowest grade of the finished pad and must have a width. .of.at least 12 inches. The continuous footings shall be embedded a minimum, of 18 inches for a two story structure below the lowest grade of the finished pad and must have a width of at least 15 inches. The steel reinforcement for the continuous footings shall consist of a minimum of two #4 rebar placed near the top and bottom of the footing with a minimum of 3" of concrete covering the top and bottom layers. C. Bearing Capacity A safe soil bearing capacity of 2,000 Pounds per Square Foot may be used in the design of these foundations. 7.3 Concrete Slabs On-Grade 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. Moisture Protection I 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. I 7.4 Sulfate exposure category I No testing for soluble sulfate concentrations has been performed by our company for the subject property soils. Severe sulfate exposure category has be default as indicated on the Third-Party Geotechrncal review for the subject property. The concrete used for the I proposed development shall consists of Type V, HS cement with a Minimum Design Compressive Strength f'c = 4,500psi and a Maximum Water-Cementitious material ratio by mass of 0.45. We recommend that a competent corrosion expert be retained to I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 19 of 29 I I evaluate the corrosion potential of the site to proposed improvements, to recommend further testing as required, and to provide specific corrosion mitigation methods for the appropriate project. I I 7.5 Earth Retaining Structures 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. Passive Pressures Passive pressures for the soil conditions at the subject site should be 350 pounds per I 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. 7.6 Minimum Driveway Pavement Recommendations I a. Permeable Interlocking Concrete Pavement (PICP) If PICP is to be used as driveway pavement the section shall meet or exceed the I following section: 3 1/8 in. Concrete Payers (ASTM C936) on 0.35 ft. of Class 3 Aggregate Base over 0.70 ft. of Class 4 Aggregate Base over Mirafi 140N (Geotextile) The pavement section shall be placed over undisturbed ground, if fill is needed this shall consists of Class 4 Aggregate Base. b. Concrete Pavement If concrete pavement is to be used as driveway pavement the concrete section shall be not less than 5.5 inches of 520-C-2500 concrete placed over native material compacted uniformly to greater than 95% of the maximum dry density (ASTM D1557). Saw-cut weakened-plane joints shall be provided at about 1 5*foot centers both ways and .at re- entrant corners. The placement slabs should be saw-cut as soon as practical, but no more than 24 hours after the placement of the concrete. The depth of the joint should be 'A of the pavement thickness and its width should not exceed 0.02-feet. Reinforcing steel is not necessary unless it is desired to increase the joint spacing recommended above. Control and isolation joints shall be sealed with elastomeric joint seal. 148 Tamarack Ave- Updated Gebtechnical Investigation JLVGIBJL 6/3/2019 Page 20 of 29 8.0 REVIEW, OBSERVATIONS, AND TESTING I (a) 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 grading 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. I 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 I 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. I . 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 I responsibility of the contractor. The contractor shall notify the owner if he considers any of the recommended actions contained herein to be unsafe. I It is a pleasure to be of service to you. Should any questions arise, please contact our office at 619-258-9000. I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 21 of 29 11 I I I REFERENCES American Society of Civil Engineers/Structural Engineering Institute, (ASCE/SEI) Standard 7-10. Bearing Capacity for Shallow Foundations -T. William Lambe & Robert V. Whitman, "Soil Mechanics" John Wiley & Sons, 1969. California Building Code (CBC 2016), 2016 California Mines and Geology Division (DMG), 1974, "Maximum Credible Rock Acceleration From Earthquakes in California", Roger. W Greensfelder 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. Geologic Map of the Oceanside 30' x 60', California Division of Mines and Geology, Michael P. Kennedy and Siang S. Tan, 2005. TOPO! [Computer Software] 1997w11df1ower productions.. (www.topo.com) San Francisco., CA: ESRI 2008 USGS National Seismic Hazards Maps.— Fault parameters. http://earthquake.usgs.gov/hazards/ USGS Seismic Design Maps for Engineers - Buildings Pre 2009 - Java Ground Motion Parameter Calculator http://earthquake.usgs.gov/hazards/designrnaps/iavacalc.php Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego California California Division of Mines and Geology (CDMG), 1995 Siang Tan and Desmond Giffen. [] h j I I I I I I I I 148 Tamarack Ave- Updated Geotechnkal Investigation JLVG/BJL 6/3/2019 Page 22 of 29 I I I I I I FIGURES I I I I I I I I I I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 23 of 29 I - - - - - - - - - - - - - - - - - - - 4 PVC WhIT 7tJ WAIL PERMEABLE PAVERS PIER DRM I ARTECTS B(DfrIG PL4\ I MW DRAIN I BLUM O%OHrA1 MASONRY__________________ I s,wc - —1B-2 TO 36" 1 OAIIB 1 TO 54" V afclR,c ti - (BELOW GROUND j 7SJ7 BELOW GROUND 7 I V PROJECT UNIX SURFACE I WAU TO um.. SURFACE PAW L 00 WON . lo 11 .L1 5250 C = (WALL TO REMEDIAL LIMITS OF GRADING i a 15170 51.75 IE urn aw L nV 1! 4 54.80 Fr DNEUM LOT 54.13 PAD iz FL QJ PE Lt- PA 1-4 I aT. or—EVST G* C iA u1 * 4 1l4I:2:T HPR6jE B' 12+55 C __ A PROTECT N R" LINES 4I, m Aj LEGEND: r REFERENCE This map was MJWI 05op6-7- OLD PARALIC T GUILET 4* PVC PIPE prepared from an existing TA r,( DEPOSITS, UNITS 6-7 R 7MU CURB FACE PS Ali Grading plan by bHa, Inc. and FLow •— --" PROPERTY LINE from the field investigation LAND _1 V performed by APPLIED r--' LIMITS OF REMEDIAL CONSULTANTS. L.J GRADING APPLIED FIFURE A: GEOLOGIC I GEOTECHNICAL MAP CONSULTANTS 148 TAMARACK AVE, Date : 6/3/19 a CARLSBAD, CALIFORNIA 92008 Drawn by: JLVG ASCE 7 Hazards Report MUCN S1Y OF moo "Em Address: 148 Tamarack Ave Carlsbad, California 92008 Standard: ASCEEI 7-10 Elevation: 53.54 ft (NAVD 88) Risk Category: II Latitude: 33,147985 Sod Class: D - Stif Soil Longitude: -117.344666 https./Iasce7hazardtooI.onlinei Page 1 of 4 Mon Jun 03 2019 1 2 4 5 6 7 8 9 S1(gvs T(s) ASCE ),ICM =OY OF avv. EWNffS Seismic Site Soil Class: D - Stiff Soil Results: Ss : 1.162 SDS: 0.802 S1 : 0.445 Sol : 0.462 F: 1.035 T1 : 8 F : 1.555 PGA: 0.464 SMS : 1.203 PGA M: 0.481 SMI : 0.692 Fpc : 1.036 I. : I 0.9 08 07 06 05 04 03 02 01 0 0 Seismic Design Category D 14 MCER Response Spectrum 12 10 08 • 0.6 ? 04 02 0- 0 Design Response Spectrum 1 2 4 5 6 7 8 9 S1 (g) vs T(s) Data Accessed: Mon Jun 03 2019 Date Source: USGS Seismic Design Maps based on ASCE/SEI 7-10, incorporating Supplement 1 and errata of March 31, 2013, and ASCE/SEI 7-10 Table 1.5-2. Additional data for site-specific ground motion procedures in accordance with ASCE/SEI 7-10 Ch. 21 are available from USGS. https://asce7hazardtool.online/ Page 2 of 4 Mon Jun 03 2019 Asa* MWrAN SIFTY ENMUS Flood Results: Flood Zone Categorization: X (unshaded) Base Flood Elevation: Refer to map for local elevations and interpolate according to the Authority Having Jurisdiction. Data Source: FEMA National Flood Hazard Layer - Effective Flood Hazard Layer for US, where modernized (httDs://msc.fema.govIoortalIsearch Data Accessed: Mon Jun 03 2019 FIRM Panel: If available, download FIRM panel here Insurance Study Note: Download FEMA Flood Insurance Study for this area tit https://asce7hazardtool.onlune/ Page 3 of 4 Mon Jun 032019 I AAlaLeNEBS The ASCE 7 Hazard Tool is provided for your convenience, for informational purposes only, and it, provided as is" and without warranties of any kind The location data included herein has been obtained from information developed produced and maintained by third party providers or has been extrapolated from maps incorporated in the ASCE 7 standard While ASCE has made every effort to use data obtained from reliable sources or methodologies ASCE does not make any representations or warranties as to the accuracy, completeness reliability currency, or quality of any data provided herein Any third party links provided by this Tool should not be construed as an endorsement affiliation, relationship, or sponsorship of such third-party content by or from ASCE. ASCE does not intend, nor should anyone interpret, the results provided by this 100110 replace the sound judgment of a competent professional having knowledge and experience in the appropriate field(s) of practice nor to substitute for the standard of care required of such professionals in interpreting and applying the contents of this Tool or the ASCE 7 standard I In using this Tool, you expressly assume all risks associated with your use. Under no circumstances shall ASCE or its.officers, directors, employees members affiliates or agents be liable to you or any other person for any direct indirect special incidental or consequential damages arising from or related to your use of or reliance on the Tool or any information obtained therein To the fullest extent permitted by law, you agree to release and hold harmless ASCE from any and all liability of any nature arising out of or resulting from any use of data I provided by the ASCE 7 Hazard Tool. https://asce7hazardtool.online/ Page 4 of Mon Jun 03 2019 F_, EXPLORATORY TEST PIT LOGS. I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 24 of 29 I Project Name: 148 TAMARACK AVE Address: 148 TAMARACK AVE CARLSBAD, CA Location: WESTERN PORTION / BEHIND (E) GARAGE Date: 4/10/2017 Logged y: JLVG Reviewed By:_JED Footing Thickness (in.): NA Boring /Test pit ID B-i Excavation Method: AUGER Sample Type BULK Total epth (ft): 4.5 Depth to Water (ft): NA Caving NONE Depth of Footing:NA - Depth (Inches) Grade Soil Description - Sample Discrete sample Interval. Bulk Sample Interval Lithol:ogy & Footing Details Type ID MC% 24 30 — Topsoil Silty Sand (SM): fine to coarse graded, orangish brown silty sand (SM) Old Paralic deposits, Units 6-7 Qop 6-7 END OF BORING @ 54" 6 12 18 24 36- 42- 48- 54 60- 66- 72 6— 12— 18— 2 - B-i 5.6% ____ - - - 36— - 54 72H ____ - 42 48 - 60— 66 ____ APPLIED CONSULTANTS - ,* BORING LOG: BORING 1. 148 TAMARACK AVE ('AThT 1AT (A L't DATE: 4/10/2017 Drawn By: JLVG Project Name: 148 TAMARACK AVE Address: 148 TAMARACK AVE CARLSBAD, CA Location: WESTERN SIDE / ADJACENT TO (E) FTG Date: 4/10/2017 Logged By:_JLVG Reviewed By:__JED Footing Thickness (in): NA Boring /Test pit ID: B2 Excavation Method: AUGER Sample Type: BULK TotalDepth (ft): 3.0 Depth to Water Caving: NONE Depth of Footing: _NA Depth (Inches) 3rade— - Sample - Discrete Bulk Interval Sample Interval Lithology & Footing Details Soil Description Sample Type ID MC% 6 12 24 30 Topsoil Silty Sand (SM): fine to coarse graded, orangish dark brown silty sand (SM) (Planter soil) ----- - Silty Sand (SM): fine to coarse graded,. orangish brown silty sand Old Paralic deposits, Units 6-7 Qop6-7 END OF BORING @ 36" - —(SM) - ____ - ____ ____ 6— - 12— 18— 24 30— 36— - 42- 48- 54- 60- 66- 72— - - 18-- - - - B-2 ____ 6.8% - - 42- 48— 54— 60— 66— 72— ____ APPLIED CONSULTANTS BORING LOG: BORING 2. 148 TAMARACK AVE, AD T QD A A rIJ)J.,rUj, DATE: 4/10/2017 Drawn By: JLVG GENERAL EARTHWORK AND GRADING GUIDELINES I I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 25 of 29 I GENERAL EARTH WORK.AND GRADING GUIDELINES L 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. I 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 I 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 I Maximum dry density tests used to determine the degree of compaction should be performed in accordance with the American Society for Testing and Materials Test Method I ASTM: D 1557-82. IL PREPARATION OF AREAS TOBE FILLED 1 1. Clearing and Grubbing: All brush, vegetation, and debris shall be removed and properly disposed of. I The Geotechiiical Consultant shall evaluate the extent of removal of these items depending on site conditions. Fill material shall not contain more than 1 percent of organic I 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 I 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 I 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 I working surface is reasonably uniform and free of uneven features which would inhibit uniform compaction. I 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 firm ground as approved by the consultant. I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 26 of 29 I I 4. Moisture Conditioning: Over-excavated and processed soils shall be waterid, dried-b ack, blended, and/or mixed, as necessary to attain a uniform moisture content I 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 1 percent according to ASTM: D1557-82. 6 Benching Where fills are to be placed on ground with slopes steeper than 5 1 I (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 I 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. I 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. 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 flu, material. - 2. Oversize: Oversize material defined as rock, or other irreducible material, with a I 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 I the oversized material is completed surrounded by compacted or densifled fill. Oversize material shall not be placed within the range of future utilities or underground construction, unless specifically approved by the consultant. 1 3. Import: If import fill is necessary for grading, the import material shall be approved by the geotechnical consultant. FILL PLACEMENT AND COMPACTION I i. 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 I 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. I 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 I 148 Tamarack Ave- Updated Geotechnical Investigation JLVGIBJL 6/3/2019 Page 27 of 29 I I 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. I 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 I sized and either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree of compaction. Fill Slopes: Compacting. of slopes shall be accomplished, in addition to normal compaction procedures, by backrolhng 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 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. SUBDRAIN IN.STALLATION 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. 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 TRENCH BACKFILL The Contractor shall follow all OSHA and CAL/OSHA requirements for maintaining safety of trench excavations. 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- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 28 of I I I I I FTJ 1 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 1 feet of trench fill. 4 The lift thickness of the trench backfill shall not exceed what is allowed in the I 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. I All work associated with trenches, excavations and. shoring must. conform to the local regulatory requirements, State of California Division of Industrial Safety codes, and I 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, I 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. I I I I I I 148 Tamarack Ave- Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 29 of 29 I