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Home My WebLink AboutCDP 2016-0004; 148 TAMARACK AVENUE; UPDATED GEOTECHNICAL INVESTIGATION; 2019-06-03-• ----.. .. -.. .. -... .. ---.. .. ----... - -.. .. --- - == -~WAPPLIED CONSULTANTS geotechnical & forensic engineering Mr. Jeff Parshalle jeff@jparch.net June 3, 2019 1941-A Friendship Drive El Cajon, CA 92020 TEL (619) 258-9000 FAX (619) 258-9004 www.applied-consultants.com Subject: Updated Geotechnical Investigation for the Subject Property Located at 148 Tamarack, Carlsbad, CA 92008 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 geotechnical 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 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 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. 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 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. 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page I of29 ... ---.. --.. .. -.. -.. .. -.. -.. -.. -... -.. ---.. -.. .. - • .. 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 oflocal 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, Bernard J. Luther, RCE 63653, CEG 1356 CEO 148 Tamarack Ave-Updated Geotechnical Investigation JL VG/BJL 6/3/2019 Page 2 of 29 -.. -TABLE OF CONTENTS .. -1.0 SITE DESCRIPTION .......................................................................................................... 4 -Fig. 1 Site Location ........................................................................................................................ 5 2.0 SURF ACE AND GROUND WATER ................................................................................. 6 -3.0 SITE GEOLOGY ................................................................................................................. 6 -3.1 Geologic Literature Review and Field Findings .............................................................. 6 -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 ........................................................................................................... 11 ◄ Fig. 4 Liquefaction Hazard Map ................................................................................................. 12 .. Fig. 5 FEMA Flood Rate Insurance Map .................................................................................... 13 4.0 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 ......................................................... 15 Table 2: Calculated Soil Pressures and Load Bearing Capacities ......................................... 15 6.0 CONCLUSIONS ................................................................................................................ 16 .. 6.1 Impact of Geologic Hazards upon Subject Property ...................................................... 16 6.2 Geotechnical Investigation Conclusions ........................................................................ 16 7.0 RECOMMEN·DATIONS ................................................................................................... 17 • 7 .1 Grading ........................................................................................................................... 17 7 .2 Shallow Foundations ...................................................................................................... 18 7 .3 Concrete Slabs On-Grade ............................................................................................... 19 -7 .4 Sulfate exposure category .............................................................................................. 19 7 .5 Earth Retaining Structures .............................................................................................. 20 7.6 Minimum Driveway Pavement Recommendations ........................................................ 20 .. 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 of29 - ... • ... .. • .. -.. -.. ... .. • -.. ,. - .. • -.. .. .. -.. Ill .. -.. .. 1.0 SITE DESCRIPTION The location of the property is at latitude 33° 8'53"N and longitude 117°20'4l"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 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 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 Geotechnical Investigation JL VG/BJL 6/3/20 I 9 Page 4 of 29 Gfoac,phlc 40£ttfen -APPLIED CONSULTANTS •'"' '"'"'"•·11111/ t c·olo;J 11 c'lfl(UU't'""' 141 Tamarack Avenue, Carlsbad, CA IZOOI Site Location Map 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page .5 of 29 .• , Fig. 1 . ,,,· ,' .f .l; / ,, ·' .f t N ---.. ---.. 11111 --.. -------- .. -.. .. -.. - -------- 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 Regional Geology: We reviewed the General Geologic Map of California (Guitierrez, Bryant, Salcedo & 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 Geology: 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. 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 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 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. 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 6 of29 • ,. -.. -- • ---.. - .. ---.. .. .. .. .. .. .. -------.. ---- 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-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 7 of29 Geographic Location Qoa # _____ •• _¥ -APPLIED CONSULTANTS f'IIIINlll,.('lftfllJll'"'""' !IC ,,,,.1,.,c·n1t,t ♦ • • • 141 T•m•rack Avenue, Carlabad, Callfomla 12001 Regional Geology Geologic Map of California (2010) 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 8 of29 i N Fig . 2 Geographic Loc1t1on: -APPLIED CONSULTANTS ,·,11 ,ru•••••1al i,·,1l0,v· CC-,.,,.,,.. ..,.,,,, 141 T1111t11rwck Annue C11rlsbo4, C111ifor11M '20H Old p■ralk deposits, Ualt 7 (late to middle Plelatocene}-Moatly poorly sorted, moderately permeable, reddish-brown, interfingered atrandline, beaeh, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the 9-11 m Bird R.ock temce (Fig. 3) Old parallc deposits, Unit 6 (late to middle Pleiatocene}-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 22-23 m Nestor terrace (Fig. 3) Geologic Map Oceanside Quadrangle 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 9 of29 i N Fig. 3 -.. -.. ---.. .. -.. .. .. --.. - Ill .. -... Ill .. .. .. .. ----.. -... -.. -- 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 . 3.3 Seismic Design Recommendations The proposed development shall be designed in accordance with seismic considerations contained in the 2016 California Building Code (2016 CBC), 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: Seismic Importance Factor (I): Occupancy Category: Site Class: Spectral Response Coefficient (Sos) Spectral Response Coefficient (SDI) Seismic Design Category 148 Tamarack Ave~ Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 10 of29 1.0 (ASCE 7-16) II (2016 CBC) D (2016 CBC) 0.802g (ASCE 7 Hazard Tool Online) 0.462g (ASCE 7 Hazard Tool Online) D (2016 CBC) ----------.. -.. .. .. .. .. -... .. --.. .. • ----... ----·• 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 6.4: 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 of adjacent structures and improvements . 148 Tamarack Ave-Updated Geotecbnical Investigation JLVG/BJL 6/3/2019 Page 11 of29 -APPLIED CONSULTANTS ,·,n "'"''"I'"'"' lfl'fllo,e, .. l'IIJIIU'r'rlllll SUBJECT PROPERTY 141 Tamarack Avenue, Carlsbad, California 12001 Potential Liquefaction ~ Riverwash ~ Tidal flats ~ Tujunp sand, 0 to 5 percent slopes ~ Other Hazard Liquefaction Hazards Map City of Carlsbad General Plan Geologic and Seismic Hazards 148 Tamarack Ave-Updated Geotecbnical Investigation JLVG/BJL 6/3/2019 Page 12 of29 t N Fig. 4 Geographic Location -APPLIED CONSULTANTS ,·11,·,ro••,~•1•1 ~••nhtlJ' d t'11tl•1·.-r,11i 141 Tamarack Avenue, Carlsbad, California 12001 FEMA Flood Insurance Rate Map 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 13 of29 ZONEA i N Fig. 5 --------------... .. --... ·• -.. ... ... .. ... -.. -.. ------ 4.0 FIELD WORK AND SOIL SAMPLING 4.1 Subsurface Investigation 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 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 #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: 4.2 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. 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: Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates -ASTM Cl36/C136M Optimum Moisture Content and Maximum Density-ASTM D1557 Standard Test Method for Expansion Index of Soils -ASTM D4829 Direct Normal "Remolded" Shear Resistance Value -ASTM D3080 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 14 of29 .. .. -.. -.. --.. -.. -.. --.. ----' -.. - ----.. .. -.. -.. ---- 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: A lied Consultants' Soils Anal ses Results Opt. Max Remolded Shear Expansion Index Moist. Density Phi Cohesion 24"-36" 10.5 121 50 2 (Ve 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 Load Bearing Sample ID Ca acit Direct Normal B-1 @24"-36" Act-Active Pass -Passive 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 15 of29 --------------.. ------------.. ---.. -- --- 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: 6.2 • 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. • 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 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. 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 16 of29 ---.. -.. -----.. .. .. ---.. .. .. -.. -.. - -.. --.. .. .. .. .. 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 a. 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 . 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 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 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 D1557) . 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 17 of29 -.. --.. -----.. -.. -.. 111 .. --.. .. ... ---... -.. -... --.. .. -.. .. 7.2 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. e. Observation and testing 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. The Consultant shall provide the following observation and testing during grading and construction: • Observation of subsurface conditions -Observe the site soil conditions through several excavation trenches to check subsurface conditions and soil properties in comparison to the approved geotechnical reports. • Laboratory testing to check soil conditions and strength parameters for design purposes. Tests included maximum dry density, in-place moisture and density. • Observation of engineered fill placement and compaction per Section IV of the attached General Earthwork and Grading Guidelines. Field density testing for compaction of the engineered fill in accordance with ASTM D1556 or ASTM D6938 methods . • Inspection of bottom of the footings trenches to be satisfactory to achieve the design bearing capacity. Shallow Foundations a. General Where foundations 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, 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. 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 18 of29 - .. .. .. .. -----.. -.. .. -• -,. ----.. .. - 1111 .. .. - .. .. ... .. .. 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 7.4 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 . Sulfate exposure category 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 Geotechnical review for the subject property. The concrete used for the 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 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 19 of 29 -.. -.. .. .. ------.. .. .. .. - -.. , .. .. -.. - .. .. -.. .. --.. - 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. 7 .5 Earth Retaining Structures 7.6 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 . Minimum Driveway Pavement Recommendations a. Permeable Interlocking Concrete Pavement (PICP) If PICP is to be used as driveway pavement the section shall meet or exceed the following section: 3 1/8 in. Concrete Pavers (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 D 1557). Saw-cut weakened-plane joints shall be provided at about 15-foot centers both ways and at re., entrant comers. 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 ¼ 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 Geotechnical Investigation JL VG/BJL 6/3/2019 Page 20 of 29 .. ... .. -.. .. .. --.. .. .. .. .. .. .. .. .. .. .. -.. .. ... -.. .. .. -.. .. .. .. 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 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. 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-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 21 of29 ---... --------.. 1111 .. .. --.. .. .. .. ... --.. -• .. -.. .. -- 1. 2. 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. 3. California Building Code (CBC 2016), 2016 4. 5. 6 . 7. 8 . 9 . 10. 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 ~d Geology, Michael P. Kennedy and Siang S. Tan, 2005 . TOPO! [Computer Software] 1997wildflower 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://earthguake.usgs.gov/hazards/designrnaps/javaca1c.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 . 148 Tamarack Ave-Updated Geotechnical Investigation JL VG/BJL 6/3/2019 Page 22 of 29 --.. .. .. -... -• -.. - -.. .. .. .. .. ... .. .. .. .. ---.. ---.. .. ... FIGURES 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 23 of29 -APPLIED CONSULTANTS _.__..,......., .......... 4" M Oll1lET ,,_, IIML ro aJllfCIIE:I( OIMIMY ~ f'A~ fE1t ; ~ I! It: ! NKHm:T'S IUUN: 1'1..ANS~ • o -ClllllC 4" Alllllt tJIIJM IOI .-r~ ;; i •"Mltf!fnt_.,-~1 ~ . "' § O'tfJffAh-. &ii .. m...\T l B-2 TO 36" +-------''------L-----...J IIWf • B-1 TO 54" ! BELOW GROUND :": ::=:, BELOW GROUND •SURFACE · .. --__ . \ . ~ SURFACE ) ,,,,,,,...,. (4" t:atc./4" Al).· 5UD,r /H.1J f'NJ A REFERENCE: This map was prepared from an existing Grading plan by bHa, Inc. and from the field investigation perfonned by APPLIED CONSULTANTS. FIFURE A: GEOLOGIC/ GEOTECHNICAL MAP 148 TAMARACK AVE, CARLSBAD, CALIFORNIA 92008 LEGEND: Qop6-7 -OLD PARALIC :~ DEPOSITS, UNITS 6-7 ,----, , ___ J PROPERTY LINE LIMITS OF REMEDIAL GRADING Date : 6/3/19 Drawn by: JL VG ASCE. Nll1£NI SOCllYlf CM. ENGINIBIS Address: 1"8 Tamarack Ave C8r1sbed, California 92008 https://asce 7h~ardtool.onlinel ASCE 7 Hazards Report Standard: ASCE/SEI 7-10 Risk Category: II Soil Class: D -Stiff Soil Page 1 of 4 Elevation: 53.54 ft (NAVO 88) Latitude: 33.147985 Longitude: -117.344666 ..... I" ( r-._...._. ~:..-~¾/, ~~ ' pa-.rAM< • "1\ : .., ,1f I .,_,1). .,, ? " -,.. , Mon Jun 03 20111 ASCE. N6JIDII SOQflY!YCM.OONl!IIS Seismic Site Soll Class: RHults: Ss: S1: Fa : F. : s .. Sw1 lelamlc DH'9n Category D -Stiff Soil 1.162 0.445 1.035 1.555 1.203 0.692 D Sos S01 TL : PGA : PGAw : FPGA ,. 0.802 0.462 8 0.464 0.481 1.036 1 MC& ReaponH Spectrum 0.G Design RnponM Spectrum 1 2 1.0 0 8 0.6 04 0.2 0 0 2 } 4 S8 (g) VI T(I) Data AccNHCI: Date Soun:•: https://asce7hazardtool.online/ 5 08 07 0 6 05 0.4 03 0.2 0.1 0 15 7 8 9 0 2 ~ 4 S.(U) YI T(I) 5 6 7 8 Mon Jun 03 2018 USGS Se11mlc Design Maps based on ASCE/SEI 7-10, lnc:orporating Supplement 1 mM1 errata of Matdl 31, 2013, Ind ASCE/SEI 7-10 Table 1.5-2. Additional datll for de epecific ground motion procedures In ac:cordance with ASCE/SEI 7-10 Ch. 21 .,. availllble from USGS. Page 2 of4 Mon Jun 03 20111 9 Flood Results: Flood Zone Categorization: X (unshaded) Base Flood Elevation: Data Source: o ... AccesNd: FIRM Panel: Insurance Study Note: https://asce 7hazardtool .online/ Refer to map for local elevations and interpolate according to the Authority HavinQ Jurildiction. FEMA National Flood Hazard Layer -Effective Flood Hazard Layer for US, where modernized <httos·J/msc tema.goyJoortal/search) Mon Jun 03 2019 If available, download FIRM panel ~ Downk>lld FEMA Flood IMUrance Study for this area ~ Page 3 of 4 Mon Jun 03 2019 -------------------- - .. .. -.. .. .. ... ---.. The ASCE 7 Hazard Tool is provided for your convenience, for informational purposes only, and is 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 Tool to 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. 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 provided by the ASCE 7 Hazard Tool. https://asce 7hazardtool.online/ Page4 of4 Mon Jun 03 2019 ... - .. -----------.. -.. --.. -... -.. .. ... .. ... ... ---.. .. - EXPLORATORY TEST PIT LOGS 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 24 of29 -------.. ---- ... ----.. .. .. -.. .. --.. ... .. .. .. .. -.. - Project Name: 148 TAMARACK AVE Address: 148 TAMARACK AVE CARLSBAD, CA Location: WESTERN PORTION/ BEHIND (E) GARAGE Boring /Test pit ID: B-1 4/10/2017 JLVG NA Depth 1--.....-S_am_p_I_e --.---tDiscrete Bulk L. h l & F · i' Soil Description it O ogy ooting (Inches) Sample Sample Details 'fl Type ID MC% Interval Interval 6 Grade-+-------------+--+---+---+---+---+----------1---.1 6 12 18 24 30 36 42 48 Silty Sand (SM): fine to coarse graded, orangish brown silty sand (SM) Old Paralic deposits, Units 6-7 Qop 6-7 B-1 5.6% 541--•-----------4 END OF BORING@ 54" 60 66 PLIED CONSULTANTS --~-BORING LOG: BORING 1 148 TAMARACK A VE, CARLSBAD, CA DATE: 4/10/2017 Drawn By: JL VG 6 12 18 24 30 36 42 48 54 60 66 72 .. .__ _____________________________________________ __, -.. --.. -.. .. --.. - • .. • ... --.. --... .. .. Project Name: 148 TAMARACK A VE Date: 4/10/2017 Address: 148 TAMARACK A VE Logged By: JLVG CARLSBAD2 CA Reviewed By: JF.D Location: WESIBRN SIDE/ ADJACENT TO (E) FTG Footing Thickness (in.): NA Excavation Method: AUGER Boring /Test pit ID: B-2 SamJ1e~e: BULK Tot De t ft: 3 Depth Sample (Inches) Soil Description Type ID MC% Grade ---- 6 Silty Sand (SM): fine to coarse graded, orangish dark brown silty 12 sand (SM) (Planter soil) 18 ----- Silty Sand (SM): fine to coarse 24 graded, orangish brown silty sand (SM) 30 Old Paralic deposits, Units 6-7 B-2 6.8% Qop6-7 36 END OF BORING@ 36" 42 48 5 60 66 PIJED CONSULTANTS --·- BORING LOG: BORING 2 148 TAMARACK A VE, CARLSBAD, CA Discrete Sample Interval Depth to Water (ft): Caving: De th ofFootin : Bulk Lithology & Footing Sample Interval Details DA TE: 4/10/2017 Drawn By: JL VG ,...._ ~ -5 6 6 12 18 24 30 36 42 48 54 60 66 72 .. .. ----------------.. .. -.. ---.. • --.. -... .. .. - GENERAL EARTHWORK AND GRADING GUIDELINES 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 25 of29 -.. ... ---.. -.. .. ... .. - ◄ .. .. .. .. ... .. .. ... -- -.. -.. --- - 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 performed in accordance with the American Society for Testing and Materials Test Method ASTM: D 1557-82 . IL 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 1 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 uniform 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 firm ground as approved by the consultant. 148 Tamarack Ave-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 26 of29 ---.. --.. -.. ------.. ---... -.. .. -.. -.. -.. -- ·• ... -.. 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-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 27 of29 .. .. ----------.. -----... --.. -.. ---.. -.. ----... - 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-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 28 of29 .. .. .. .. -.. -• .. .. -.. --.. • -.. -.. .. - ---.. .. .. -... ---.. .. • 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-Updated Geotechnical Investigation JLVG/BJL 6/3/2019 Page 29 of29 .. .. .. .. -... -.. --.. .. .. .. -.. .. -.. -.. -,. .. .. -.. - ----.. Mr. Jeff Parshalle jeff@jparch.net June 3, 2019 1941-A Friendship Drive El Cajon, CA 92020 TEL (619) 158-9000 FAX(619) 258-9004 www.applied-consultants.com 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. ParshaUe: 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 I. Due to the age of the "Geotechnical Investigation ... " (Reference 1), the Consultant should provide an updated geotechnical report a_ddressi~g the plans, and pro~de u~a~ grading and foundation recommendations cons1stent with the 2016 Caltforma Bmldmg 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 2. The Consultant should review the project grading and foundation plans. provide any additional geotechnical recommendations considered n~essary, and con?11n that_ the plans have been prepared in accordance with the geotechmcal 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 Party Geology review (1 st review) JLVG/BJL 6/3/2019 Page I of4 -- ---.. .. -.. .. -------- ---.. • .. .. .. -.. .. -----... lssue#3 3. The Consultant should provide an updated geotechnical map/plot plan utilizing thehlatesb)t grading plan for the project to clearly show (at a minin:ium) a) existing site to~ograp y, proposed structures/improvementq, c) proposed firush~d grnd~ d) ~ocattons of the subsurface exploration, e) geologic contacts, and f) remedtal grad1~g hm1ts. 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 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 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 6. The Consultant should identify the geologic units encountered on the boring logs . 7. The "Borings Location" plan depicts two boring number B-1,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. l 48 Tamarack Ave -Third Party Geology review (1st review) JLVG/BJL 6/3/2019 Page 2 of4 .. ... .. .. -.. - --.. ------.. .. --.. ... • .. .. .. • .. - .. .. .. .. .. Issue#8 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 9. The Consultant should provide a statement regarding the impact of the proposed grading and constmction on adjacent prope1ties 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 10. The Consultant should clarify if the remedial grading recommendations apply to the detached garage strL1cture . 11. The Consultant should provide remedial grading recommendations for proposed driveway/hardscape areas. 12. 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 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 14. The Consultant should provide hardscape recommendations (thickness, reinforcement, joints, etc.) . 15. 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 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. Sincerely, .,.,e;:.---=:::;;.._--t:::~-----__,.,_--,, Bernard J. Luther, RCE 63653, CEG 1356 CEO .. .. --.. .. -.. .. .. ... ... .. -.. .. -.. • .. .. .. • -.. • .. .. • -.. -• -- Mr. Jeff Parshalle jeff@jparch.net June 4, 2019 1941-A Friendship Drive El Cajon, CA 92020 1'HL (619) 258-9000 FAX (619) 258-9004 www.applied-consultants.com 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-?A, 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-1, 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 1 of l Bernard J. Luther, RCE 63653, CEG 1356 CEO