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PD 2023-0008; 3229 HIGHLAND; UPDATED PRELIMINARY GEOTECHNICAL INVESTIGATION FOR 3229 HIGHLAND; 2023-07-27
--=== ~~ APPLIED CONSULTANTS geotechnica/ & forensic engineering JC Collins and Jeannine Woo 2633 Lincoln Blvd, Unit 941 Santa Monica, CA 90405 July 27, 2023 1941-A Friendship Drive El Cajon, CA 92020 TEL (619) 258-9000 www.applied-consultants.com Subject: Updated Preliminary Geotechnical Investigation for the Subject Property Located at 3229 Highland Drive, Carlsbad, CA, 92008 Dear Mr. Collins & Mrs. Woo, In accordance with your request, we have prepared this geotechnical investigation report for the subject property located at 3229 Highland Drive, 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 construction of a new two-story residence with a partial daylight basement and a detached single-story ADU and a below grade swimming pool. 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. PRELIMINARY GEOTECHNICAL INVESTIGATION CONCLUSIONS After reviewing the results of our geotechnical investigation, we conclude 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. Remedial grading shall be performed prior to construction of the proposed development and shall consist of removal of existing loose fill soils until competent soils are encountered and the recompaction of the fill soils to the required grade. Contact with competent materials is expected within four feet below existing grade. The bottom of excavations shall be approved by a representative of our firm. Upon approval, the upper 6" of the base of excavation shall be scarified, and the fill soils recompacted to equal to or greater than 90% of optimum compaction to the required finish grade. The building pad shall be underlain by a minimum of three feet of recompacted fill. Driveways and parking areas shall be underlain by a minimum of one foot of recompacted fill. Root system of adjacent longevous trees extends into the area of the proposed development. An arborist shall be consulted, and mitigation shall be performed such that the root system is terminated at least five feet outside the proposed development footprint. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page I of32 The bottoms of the excavations shall be approved by our project geologist, engineer, or technician supervisor prior to placing fills or constructing improvements. If the subsurface materials are determined to be unsuitable when observed, they shall be removed to below contact with competent material. We appreciate this opportunity to be of service. Should you have any questions, please call our office at (619) 258-9000. Sincerely, nzalez, PE 92051 Project Engineer 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 2 of32 TABLE OF CONTENTS 1.0 SITE DESCRIPTION .......................................................................................................... 4 1.1 PRIOR USAGE / HISTORIC AERIAL PHOTOGRAPHS REVIEW ................................ 4 Fig. 1 ............................................................................................................................................... 6 2.0 SURFACE AND GROUND WATER ................................................................................. 7 3.0 SITE GEOLOGY ................................................................................................................. 7 3 .1 Geologic Literature Review and Field Findings .............................................................. 7 Fig. 2 ............................................................................................................................................... 9 Fig. 3 ............................................................................................................................................. 10 3.2 Tectonic Setting .............................................................................................................. 11 3.3 Seismic Design Recommendations ................................................................................ 11 3.3 Geologic Hazards ........................................................................................................... 12 Fig.4 ............................................................................................................................................. 13 4.0 FIELD WORK AND SOIL SAMPLING .......................................................................... 14 4.1 Subsurface Investigation ................................................................................................ 14 4.2 Soil Sample Analyses ..................................................................................................... 14 5.0 FINDINGS ......................................................................................................................... 14 5.1 Soils Laboratory Analyses Findings ............................................................................... 14 Table 1: Applied Consultants' Soils Analyses Results ......................................................... 14 6.0 CONCLUSIONS ................................................................................................................ 15 6.1 Impact of Geologic Hazards upon Subject Property ...................................................... 15 6.2 Geo technical Investigation Conclusions ........................................................................ 15 7.0 RECOMMENDATIONS ................................................................................................... 16 7.1 Grading ........................................................................................................................... 16 7 .2 Shallow Foundations ...................................................................................................... 19 7 .3 Concrete Slabs On-Grade ............................................................................................... 19 7.4 Exterior Concrete Flatwork ............................................................................................ 20 7 .5 Earth Retaining Structures .............................................................................................. 20 7.6 Swimming pool construction .......................................................................................... 21 7.7 Permeable pavers ............................................................................................................ 22 7 .8 Sulfate exposure ............................................................................................................. 22 7.9 Temporary Excavation Slopes ........................................................................................ 23 7 .10 Site Drainage ............................................................................................................... 23 8.0 REVIEW, OBSERVATIONS, AND TESTING ............................................................... 24 FIGURES ...................................................................................................................................... 26 EXPLORATORY TEST PIT LOGS ............................................................................................ 27 GENERAL EARTHWORK AND GRADING ............................................................................ 28 GUIDELINES ............................................................................................................................... 28 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 3 of32 1.0 SITE DESCRIPTION The location of the property is at latitude 33° 9'48"N and longitude 117°20'1 0"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 Highland Dr is assumed to be east. The subject property is bounded on the north by Pine Ave; to the east by Highland Drive; and to west and south by other existing residential dwellings. Review of the current topographic map for the site indicates that the subject property is at approximately 171 feet with respect to the North American Vertical Datum of 1988 (NA VD 88) The subject property is a rectangular shaped parcel of approximately 0.48 acres that moderately slopes (10-15%) from east to west. The lot is currently occupied by an existing one-story wood framed single family residence, a single-story companion unit and a detached garage. The proposed development is the construction of a new two-story residence with a partial daylight basement and a detached single-story ADU. 1.1 PRIOR USAGE / HISTORIC AERIAL PHOTOGRAPHS REVIEW i) Historical Aerials (HistoricalAerials.com) We have reviewed historical aerial photographs of the subject property and surrounding area. We noted the following: -The 1938 historical aerial photograph shows the subject property undeveloped. The surrounding properties show equally spaced vegetation. The most probable assumption is that the prior usage of the neighboring properties was agricultural. -The 1947 historical aerial photograph still shows the subject property undeveloped. The surrounding properties show equally spaced vegetation. -The historical aerial photographs after 1953 show the subject property and surroundings as developed. ii) Topographic Maps (USGS) Review of the historical topographic maps of the region indicate that no substantial changes in topography have occurred since 1942. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 4 of32 iii) Prior Geotechnical Reports and Grading plans The subject property did not have readily available previous grading plans or geotechnical reports for review. The only relevant geotechnical report found was from a property located at Highland Drive approximately 250 feet south of the subject property. The report is referenced by: City Of Carlsbad Project# PD 2019-0012 Title: Report of Preliminary Geotechnical Investigation Proposed Ward Residence, 3291 Highland Drive, Carlsbad, California Prepared by: Christian Wheeler Engineering Dated: October 5, 2020. Similar to our site reconnaissance, the field exploration performed by Christian Wheeler Engineering describes contact with old paralic deposits at a shallow depth. According to Christian Wheeler Engineering's report, results of water-soluble sulfate content 0.0005 percent, where soils with soluble sulfate content ofless than 0.1 percent are considered to be negligible. iv) Prior usage conclusions Based upon the available aerials, maps, reports and our field exploration, it is our assumption that the subject property prior usage was a vacant lot until the 1950's and that the subject property was then developed with the existing structures. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JL VG/JED 7/27/2023 Page 5 of 32 i ( ~-------- ll111•11n l .<1ywm Geographic Location 3229 Highland Drive, Carlsbad, CA, 92008 •• -~-·· .. , :~. ·APPLIED CONSULTANTS Site Location Map 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JL VG/JED 7/27/2023 Page 6 of 32 l N Fig. 1 2.0 SURFACE AND GROUND WATER On May 26, 2022, 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 four borings as part of our reconnaissance. The borings were taken within the subject property to a maximum depth of four feet below 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: Pluvial 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 Qop2-4: Qop4 is defined as : Old Parlic deposits, Unit 4 (late to middle Pleistocene) -Mostly poorly sorted, moderately permeable, reddish-brown, interfingered strandline, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JL VG/JED 7/27/2023 Page 7 of32 Locally the materials encountered are: Hand Boring # 1 : From grade to twenty-four inches below grade a fine to medium grained, loose, reddish brown silty sand (SM) was encountered. From twenty-four inches below grade to forty inches below grade a fine to medium grained, dense, reddish light brown silty sand (SM) was encountered. Hand Boring #2: From grade to fourteen inches below grade a fine to medium grained, loose, reddish brown silty sand (SM) was encountered. From fourteen inches below grade to forty-eight inches below grade a fine to medium graded, reddish light brown silty sand (SM) was encountered. Hand Boring #3: From grade to twenty-four inches below grade a fine to medium grained, loose, reddish brown silty sand (SM) was encountered. From fourteen inches below grade to forty-eight inches below grade a fine to medium graded, reddish light brown silty sand (SM) was encountered. Hand Boring #4: From grade to twenty-four inches below grade a fine to medium grained, reddish brown silty sand (SM) was encountered. From fourteen inches below grade to forty-two inches below grade a fine to medium graded, reddish light brown silty sand (SM) was encountered. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 8 of32 Ge :>a 7· ~~;-_-: • . .;---APPLIED CONSULTANTS E Mzv Qoa 3229 Highland Drive, Carlsbad, CA, 92008 Regional Geology Geologic Map of California (2010) 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 9 of32 i N Fig. 2 Geographic Location: 3229 Highland Drive, Carlsbad, CA, 92008 Old paralic deposits, Unit 4 (late to middle Pleistocene)-Mostly poorly sorted, moderately penneable, reddish-brown, interfingered strandline, beach, estuarine and colluvial deposits composed of siltstone, sandstone and conglomerate. These deposits rest on the 34-37 m Stuart Mesa terrace (Fig. 3) i N : -':.:__::·,::,+. APPLIED CONSULTANTS Geologic Map Oceanside Quadrangle Fig. 3 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 10 of32 3.2 Tectonic Setting Southern California, including the City of Carlsbad and surrounding areas, is in an area of late Tertiary to Quaternary-aged fault zones (Kennedy 1975) which strike generally to the northwest. Some of these fault zones are known to be active according to the California Geological Survey. "Active" faults are ones which have had faulting activity within the Holocene Epoch, or the last 11,700 years. The area's most prominent and active faults are those within the Newport- Inglewood-Rose Canyon Fault Zone. Active faults within this fault zone present the most immediate seismic hazards to San Diego and environs. Other Fault zones including the Elsinore fault zone lie in eastern and northern San Diego county. Fault rupture hazard would affect a property if an active fault trace or traces traverse the property. The subject property is not within an Alquist-Priolo Earthquake Fault Zone (Special Studies Zone). The site is about 8.5 miles northeast of faults within the active Newport- Inglewood-Rose Canyon Fault Zone (offshore Oceanside section) with a maximum moment magnitude of 6.9, and 23.8 miles southwest of the Julian section of the active Elsinore Fault Zone with a maximum moment magnitude of 7 .1. Even though direct ground rupture from faulting directly underneath the subject property is not likely, the property will be subjected to considerable ground acceleration and shaking from an earthquake event along nearby faults. The intensity of ground shaking is dependent on distance from faults, earthquake magnitude and duration, and seismic characteristics of foundation soils and bedrock. According to the USGS Seismic Design Maps based on ASCE/SEI 7-16, the most probable peak ground acceleration for the subject property is 0.459g. 3.3 Seismic Design Recommendations The proposed development shall be designed in accordance with seismic considerations contained in the 2022 California Building Code (2022 CBC), American Society of Civil Engineers (ASCE) Standard 7-16: Minimum Design Loads for Buildings and other Structures and City of Carlsbad requirements. Based on the 2022 CBC and ASCE 7-16, the following parameters may be considered for design: Seismic Importance Factor (I): Occupancy Category: Site Class: Spectral Response Coefficient (Sos) Spectral Response Coefficient (Ss) Spectral Response Coefficient (S1) 1.0 (ASCE 7-16) II (2022 CBC) D (2022 CBC) 0.776g (ASCE 7 Hazard Tool) 1.097g (ASCE 7 Hazard Tool) 0.395g (ASCE 7 Hazard Tool) 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 11 of32 3.3 Geologic Hazards 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. 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 near 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 171 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. Provided that our geotechnical recommendations included in this report are followed, it is our professional opinion that the proposed grading and construction will not measurably destabilize nor impact adjacent properties and improvements. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 12 of32 \ \, \ . \ . • \\\ : · --; --.-,. ,··!~:APPLIED CONSULTANTS gf'orec~r.,~ :1 & fo,ens,c er:gmee,,n9 3229 Highland Drive, Carlsbad, California 92008 Potential Liquefaction ~ Riverwash 8 Tidal flats ~ Tujunga sand, 0 to 5 percent slopes ~ Other Hazard Liquefaction Hazards Map City of Carlsbad General Plan Geologic and Seismic Hazards 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 13 of32 t N Fig. 4 4.0 FIELD WORK AND SOIL SAMPLING 4.1 Subsurface Investigation On May 26, 2022, a representative from Applied Consultants conducted the field investigation. Four exploratory borings were hand augered as part of our investigation: Hand Boring #1 (HB-1) was excavated to a depth of three feet and three inches below existing grade located towards the northeast portion of the property. (EL. 170ft) Hand Boring #2 (HB-2) was excavated to a depth of four feet below existing grade located towards the southeast portion of the property. (EL. 168ft) Hand Boring #3 (HB-3) was excavated to a depth of three feet below existing grade located towards the west portion of the property. (EL. 164ft) Hand Boring #4 (HB-4) was excavated to a depth of thirty inches below existing grade located adjacent to the existing carport towards the south of the property. (EL. 158 ft) 4.2 Soil Sample Analyses The purpose of collecting the bulk soil sample was to determine the soil physical characteristics through laboratory testing. The soil sample was analyzed for the following: Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates -ASTM C136 I 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 5.0 FINDINGS 5.1 Soils Laboratory Analyses Findings The following table (Table 1) is a compilation of our soils analyses results from the sample collected within the area of the proposed development. Table 1: Applied Consultants' Soils Analyses Results Sieve Analysis Opt. Max Remolded Shear Expansion Cu Cc %Fines uses Moist. Density Phi Cohesion Index Sample ID (%) (pcf) (angle) (psf) HB-1@ 7.1 2 14.1 SM 10.6 126 31 100 5 (Very Low) 24"-36" pcf -pounds per cubic foot psf -pounds per square foot 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 14 of32 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 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. 6.2 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. Remedial grading shall be performed prior to construction of the proposed development and shall consist of removal of existing loose fill soils until competent soils are encountered and the recompaction of the fill soils to the required grade. Contact with competent materials is expected within four feet below existing grade. The bottom of excavations shall be approved by a representative of our firm. Upon approval, the upper 6" of the base of excavation shall be scarified, and the fill soils recompacted to equal to or greater than 90% of optimum compaction to the required finish grade. The building pad shall be underlain by a minimum of three feet of recompacted fill. Driveways and parking areas shall be underlain by a minimum of one foot of recompacted fill. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 15 of32 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 I 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. The root system of adjacent longevous trees extends into the area of the proposed development. An arborist shall be consulted, and mitigation shall be performed such that the root system is terminated at least five feet outside the proposed development footprint. c. Site Preparation Remedial grading shall be performed prior to construction of the proposed development and shall consist of removal of existing loose fill soils until competent soils are encountered and the recompaction of the fill soils to the required grade. Contact with competent materials is expected within four feet below existing grade. The bottom of excavations shall be approved by a representative of our firm. Upon approval, the upper 6" of the base of excavation shall be scarified, and the fill soils recompacted to equal to or greater than 90% of optimum compaction to the required finish grade. The building pad shall be underlain by a minimum of three feet of recompacted fill. Driveways and parking areas shall be underlain by a minimum of one foot of recompacted fill. Localized areas may require deeper removals. Minimally, the removals should extend a lateral distance of at least five feet beyond the limits of settlement sensitive structures and/or the limits of structural fill. If deeper removals are performed, where possible the removals should extend a lateral distance equal to the depth of removal beyond the improvement limits. Removal bottoms should expose competent materials in a firm and unyielding condition. The extent of removals can best be determined in the field during grading when observation and evaluation can be performed by a representative of our firm. The bottoms of the excavations shall be approved by our project geologist, engineer, or technician supervisor prior to placing fills or constructing improvements. If the subsurface materials are determined to be unsuitable when observed, they shall be removed to below contact with competent material. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 16 of32 After excavation of the proposed basement, the upper 6" of the basement pad key shall be scarified and recompacted to greater than 90% of optimum compaction. Root system of adjacent longevous trees extends into the area of the proposed development. An arborist shall be consulted, and mitigation shall be performed such that the root system is terminated at least five feet outside the proposed development footprint. d. Fill Material The materials onsite may be used as compacted fill. If it is necessary to import fill material, the material should be approved by the geotechnical consultant. All fill material must be compacted uniformly to 90% of the maximum dry density (ASTM D 1557). e. Transition Pad Grading Support of structures partly on cut and partly on fill is not recommended. In order to provide uniform bearing conditions beneath the structures, the cut portion of cut/fill transition pads shall be excavated to three feet and be replaced as uniformly compacted, structural fill material. In this case, the overexcavated area shall be sloped at an inclination of at least two percent towards the fill side of the pad, in such a manner that the water does not become trapped in the overexcavated zone. f. Processing of Fill Areas Prior to placing any new fill soils or constructing any new improvements in areas that have been cleaned out to receive fill, the exposed soils shall be scarified to a depth of six inches, moisture conditioned, and compacted to at least 90 percent relative compaction. In areas to support fill slopes, keys shall be cut into the competent formational material. The keys shall be at least ten feet wide and be sloped back into the hillside at least two percent. The keys shall extend at least one foot into the competent formational material. No other special ground preparation is anticipated at this time. g. Compaction and Method of Filling All structural fill placed at the site shall be compacted to a relative compaction of at least 90% of its maximum dry density as determined by ASTM Laboratory Test D1557. Fills shall be placed at or slightly above optimum moisture content, in lifts six inches thick, with each lift compacted by mechanical means. Fills shall consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by our soil technicians or project geologist. Fill material shall be free of rocks or lumps of soil in excess of 4 inches in maximum dimension. Fills shall be benched into all temporary slopes and into competent natural soils when the natural slope is steeper than an inclination of 5: 1 (horizontal to vertical). Keys shall be constructed at the toe of all fill slopes. The keys shall extend at least 12 inches into firm natural ground and shall be slope back at least two percent into the slope area. Slope keys 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JL VG/JED 7/27/2023 Page 17 of 32 shall have a minimum width of ten feet. Utility trenches backfill within five feet of the proposed structures and beneath all pavements and concrete flatwork shall be compacted to a minimum of 90 percent of its maximum dry density The upper twelve inches of subgrade beneath paved areas shall be compacted to 95 percent of the materials maximum dry density. This compaction shall be obtained by the paving just prior to placing the aggregate base material and shall not be part of the mass grading requirements or operation. h. Imported Fill Material: At this time the need to import fill material is not anticipated. However, if imported fill is necessary, it shall be evaluated and approved by the Geotechnical Consultant prior to being imported. At least two working days' notice of a potential import shall be given to the Geotechnical Consultant so that appropriate testing can be accomplished. The type of material considered most desirable for import is a nondetrimentally expansive granular material with some silt or clay binder. i. Observation and testing It is necessary for a geotechnical consultant, 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 Dl556 or ASTM D6938 methods. • Inspection of bottom of the footings trenches to be satisfactory to achieve the design bearing capacity. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 18 of32 7.2 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. 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 18 inches below the lowest grade for a one-story structure and have a minimum width of 12 inches. The spread footings shall be embedded a minimum of 24 inches below the lowest grade 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 18 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 24 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 shallow foundation with recompacted soils. 7.3 Concrete Slabs On-Grade a. Floor Slab If any interior floor slabs are used for this project they should be no less than 5" (actual). For one-story or greater structures, slab reinforcement should consist of #4 rebar placed at 18" on center. All slab reinforcement should rest on concrete chairs or a suitable substitute. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JL VG/JED 7/27/2023 Page 19 of 32 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 two inches of clean sand and be overlain by two inches of clean sand. 7.4 Exterior Concrete Flatwork Concrete flatwork shall be a mm1mum of 4 inches thick and be reinforced with a minimum of #3 rebar spaced at no more than 18 inches on center. Thickened edges shall be provided adjacent to perimeter slabs and landscape areas and shall be a minimum of 8 inches thick. Controls joints shall be constructed at no more than 10 feet apart in both directions. For sidewalks, control joints shall be provided spaced at no more 6 feet. The control joints shall be sawed, grooved or formed and shall be extended into the slab to a depth of one fourth of the slab thickness. 7.5 Earth Retaining Structures a. Retaining wall foundations The retaining wall foundations shall be embedded to a minimum of twelve inches into competent native soils or into recompacted soils to greater than 90% of optimum compaction. 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 values. 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. b. Design Parameters The following values shall be used for the design of the earth retaining structures for the subject property: Equivalent Fluid Pressure Level Backfill 2: 1 Sloping Backfill Active Pressure (Unrestrained) 42pcf 62 pcf At-rest Pressure (Restrained)* 65 pcf 85 pcf Passive Pressure 350 pcf 350 pcf (Level toe) Passive Pressure 150 pcf 150 pcf (2:1 Descending Slope) 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 20 of32 -Unit weight of soil = 126 pcf -Cohesion = 100 psf -Kh = 0.18, Seismic loading (H > 6 feet) -Strength Level Seismic force factor (Fp/Wp) = 0.20 -Coefficient of friction of soil to concrete = 0.30 -Allowable Bearing Pressure = 2,000 psf * The cantilever retaining wall sections adjacent to retaining wall comers shall be designed to withstand At-rest pressures for an equivalent horizontal distance of H (height of wall) ** The structural designer shall consider surcharge loads from adjacent structures or vehicular loads into the retaining wall design where applicable. ***The retaining structure should have a granular backfill and adequate drainage to prevent the buildup of hydrostatic pressures. The architect should provide details for the drainage and waterproofing of the retaining structures. c. Retaining Wall Subsurface Drainage All retaining walls shall have a subsurface drainage system behind them to prevent buildup of hydrostatic pressures. Conventional concrete or CMU retaining walls shall be backfilled with clean sand and gravel. The immediate twelve inches behind the retaining walls shall be backfilled with ¾" gravel protected with filter fabric. A minimum 4" perforated Schedule 40 PVC or ABS drainpipe shall be installed at bottom of wall. The drainpipe shall positively slope where water can be removed by pumping or gravity. Backfill beyond the gravel drain should consist of clean granular material compacted to greater than 90% of relative compaction. While all backfills should be compacted to the required compaction, extra care should be taken when working close to walls to prevent excessive pressure buildup. Prefabricated drainage composites such as Miradrain 6200, or equivalent, shall be used for shotcrete retaining walls constructed against temporary shoring. d. Allowable horizontal deflection Retaining walls designed with the recommended parameters included in this report are expected to have a maximum horizontal deflection of 1 % of the retained height. 7.6 Swimming pool construction The swimming pool walls shall be capable of supporting the water in the pool without soil support. The swimming pool footings shall be extended such that a minimum 1 0' to daylight is established. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 21 of32 Drainage shall consist of either a drainage composite such as Miradrain 6200, Mirafi G 1 00W or a 12-inch thick free draining gravel blanket. Free draining gravel shall consist of Caltrans Class II permeable material or ¾" clean gravel wrapped in Mirafi 140N filter fabric or equivalent. The drainage shall extend from the swimming pool/jacuzzi water level to bottom of pool shell. The swimming pool/jacuzzi shell bottom shall rest upon a 12" thick drain rock blanket wrapped in filter fabric. A 4" perforated Schedule 40 PVC or ABS drain pipe shall be installed at the deepest point of the spa in the gravel to facilitate the collection of water. The pipe shall slope a minimum two percent slope where water can be removed by pumping or gravity. Concrete for swimming pool/jacuzzi shall have a water cement (w/c) ratio of 0.45 or less 7.7 Permeable pavers a. Driveways and parking Permeable pavers used for the driveway and parking areas shall be rated for vehicular traffic. The upper 12 inches of the subgrade soils and the aggregate base shall be compacted to a minimum of 95 percent relative compaction (ASTM Dl557). After compaction of the subgrade, a layer of geogrid Mirafi 3XT or equivalent installed below the rock storage section. The perimeter of the proposed pavers shall be bounded by a concrete curb with a minimum embedment of 18" below the bottom of the rock storage section. b. Pavers adjacent to foundations The proposed foundations adjacent to permeable pavers are suitable provided that the foundations are extended or cut-off-walls are constructed such that the foundations or cut-off-walls bottoms extend two feet below the bottom of the base rock storage section. The positive side of the foundations/structures adjacent to permeable pavers shall be protected with Miraseal, or equivalent and Miradrain 6200, or equivalent. The sub grade of the pavers shall be graded a minimum of 5% away from all structures. 7.8 Sulfate exposure No testing for soluble sulfate concentrations had been performed by our company for the subject property soils. However, previous reports from the area indicated that negligible corrosion potential for concrete and severe corrosion potential for steel was observed in the near surface soils. Accordingly, no special considerations regarding corrosivity are recommended for this site. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JL VG/JED 7/27/2023 Page 22 of 32 7.9 Temporary Excavation Slopes Temporary excavation slopes in the existing subsurface soils and or bedrock may be made vertical for cuts less than four (4) feet and where no existing structures are located within seven feet or within the 45-degree zone of influence pressure from adjacent structures. Additionally, a combination of a 1: 1 cut slope with vertical cut less than 4' is acceptable; provided that the given condition is inspected immediately by the geotechnical engineer of record to verify that the soils present verify our logs. For deeper cuts, temporary excavation slopes shall be made no steeper than 1 :1 (horizontal to vertical). In areas where soils with little or no binder ( cohesion) are encountered, shoring or flatter excavation slopes shall be made. Your attention is directed to the fact that while caving was not encountered in the test excavations, it is possible that a trench or excavation could react in an altogether different manner. All excavations shall be made in accordance with the governing regulations of the State of California Division of Industrial Safety. These recommended temporary slopes do not preclude local raveling and sloughing. If temporary excavation slopes do not comply with the above, a temporary shoring system shall be designed and installed to withstand surcharge from adjacent structures in addition to the active and passive pressures generated by the vertical cut. 7.10 Site Drainage (a) Surface grades adjacent to buildings should be designed and constructed to direct and facilitate drainage away from structures to approved drainage facilities. Recommended minimum grade in unpaved soil areas around buildings and asphalt-paved areas is 5 percent, and in concrete paved areas is 2 percent. Accumulation of water around buildings should be avoided. Concentrations of surface run-off should be collected and drained to suitable discharge outlets. (b) Approved drainage patterns should be installed and maintained throughout the life of structures. The building and surface drainage facilities should not be altered without the prior review and approval of the Project Civil Engineer. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 23 of32 8.0 REVIEW, OBSERVATIONS, AND TESTING (a) The final grading/ foundation 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. (b) All construction activities during grading and foundation excavations should be continuously monitored and observed by the Geotechnical Engineer and Engineering Geologist of Record. (c) 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. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 24 of32 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. REFERENCES American Society of Civil Engineers/Structural Engineering Institute (ASCE/SEI) Standard 7-16. Bearing Capacity for Shallow Foundations -T. William Lambe & Robert V. Whitman, "Soil Mechanics", John Wiley & Sons, 1969. California Building Code (CBC 2022), 2022 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] 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:! /earthquake. usgs.gov/hazards/ designmaps/javacalc.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. - 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 25 of32 FIGURES 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 26 of32 / ,.._ ' f I/ 0 50 ,oo -2 .. - - ''LEGEND: Qop2-4-OLD PARALIC DEPOSITS, UNITS 6-7 SPHERE SURVEYING AND MAPPING, INC. 330 LUISENOAVcNUE OCEANSIDE, CA. 92!J57 -APPLIED CONSULTANTS --·- SITE ADDRESS: 3229 HIGHLAND AVENUE C4RLSBAD, CA. 92008 HB-1 \. BORING LOCATION FIGURE A: GEOLOGIC / GEOTECHNICAL MAP (TOPO SURVEY BASE) 3229 HIGHLAND DRIVE, CARLSBAD, CA 92008 / -1~- ~ ~ ~ ) I ,,f I I ,, ~ I i REFERENCE: This map was prepared from a Topographic Survey by William Tuck, LS and ml from the field investigation performed by APPLIED si.l CONSULTANTS. Date : 6/5/22 Drawn by: J L VG .APPIJED CONSULTANTS ~fol' ~ It ~ 7 I . 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' ·, ·-1.,'·• PROPOSED I l ' / ,-' : -·· i=--. ·,., 1:?_:~·, .I ', '.·' ~,=-,-· ·1 ,' ( / L._, :. RESIDENCE I 1J ,' ,· I ~ ''T"---· ' • I I .· I ' • I ·.H,.B·-4 _ ,. . ;~~~~:~ ~.o.o,~ ,.:;·1r:1,· 1· I ( ··:~:... 5,976 NET SF I i/·• •• _ I; j J)l!\ I . •"'<;-'-~ H '~R~C"e-1 ·:--~-:=:::-r:·: , ;:.:::-::,. 1\ ,·. ,L-':!; II _fr ' /?-:-_J 1~1.-.\.1/. ·r;r" r --Ii I t B-21 1::.._; •.. :·, / 1' ·' \ '; •• f ''G"-. l j :--1 I I . --, •• "· l '•· '·t , I ·, :· ,... . i.i:::'·-4 ;·· •. • ' . .1:.; ,. I -I • ' I \;:-_,·,:-:<ri:-;J·. :,.... -:··--:J--::--: ~ , /,1 _,; . 1,,.;a,, _;,_;_..... i' ,; n .: I \ r' '. -. . i~:. / I I .. --· . I' p r--""~· b I ;... 1-:-_-:!i 1-'-f='½"-':+':_ __ ;__/_ __ .,... .-! ·I 1 ./ PUK 0 t~GR ,, -1 ./· .. ·,/ , . , 1 1 , ! f/-.J,1 / \ . \ i1 \,, L_ . . I I / ' J ' : ' \ : 1-• q I -;---1----·--,-~-· --: -.:. -:'--J,: ! ,: -=.~ __ ., --. i.~~ ·~ 'I / ' f.i,-l'~~j•,;J \ • I •, ---•. :,~=-=-::---:-.-~ I' ,,. ,, I• LEGEND: Qop2-4-OLD PARALIC DEPOSITS, UNITS 6-7 ~B-1 BORING LOCATION FIGURE B: GEOLOGIC/ GEOTECHNICAL MAP (PRELIMINARY SITE PLAN BASE) 3229 HIGHLAND DRIVE, CARLSBAD, CA 92008 / REFERENCE: This map was prepared from a Preliminary Site Plan by Carlos Architects and from the field investigation performed by APPLIED CONSULTANTS. Date : 6/5/22 Drawn by: JL VG l'l/1& i,VDJUE "''' ~ ~ l'~~~ ":· ;.ie-'t . . ' •• y. @11 I • • @f~✓i, iY. •• " .,, .. ~ I: ~. . '§ "6-.~,, --. '1 11"·. All \ : " ! •:~W-ffl :~'; 1··-----------. . . _____ _,_,,,,..113__ "-'I • ~--• ·~: :;:;:: ':.' • \ /I :;,"""-"""", - 1 \ , -------------·--------·-; • I, I ,"'1 ,,,,ill • __..r'.·~ I • --•"" ~ I /t; '14:,·· 'j:: ~tJ,; • --H ~~ .. ::.7 • ~,.,AN .J,!.}f.P1 1 \ ~.,,__~--• C!:m:: I S.~/'# / ~---:.:;;_ -~: '·.'1'» ~ : .. ,· , r•I , \\ -.. ~!,..-,_r.' __ "'_1,1,; _m t v r / @ ~i!.t 1 , -:~-[;~.. ·~_,.,, t1v." D ·" .,, . : ~-" -~ i' A ~ i ~~-.....!I:.~.t!!~-'lf?l~,~~!,.t:,j~or~~-~,--;:."~~;----~~~~~~L.__:~ i I ~ ',1: ·,i,.~~i......., \ I Jfil : : ~~-'llj.__'l ,,.J ' ·\1 11 I ~ ' ,. = "if".._ 1 ,,,,.._ I I : l I • ---t.!' iiJ.-···~ ..,.___ j :_~,ic:,: 'I APPROX. LIMITS Al ! 1 :--w-1 ~ -, ._.;f JJ&Zi / 'g; • OF REMEDIAL ; ______ ,w_,_ ' ..,,.~' ''T"""t....!.,.-....Y • ' !"-:-·•.: ,-,,~-----ii,-.• -~--y ffi\".itff-.-+: ; ·f--+--_. : ! GRADING "k-tY ,~--~ ~-~ r -1 :"'j --! (DEVELOPMENTFOOTPRINT m:MWl;., 1 I tJ-. · I """' !i '-sc--.-l-f"'{1/Jl .::.:L. j + 5 FEET OFFSET & PAVING ' .. -,,.,_ ""'"-" ~ ' ill>< ' ~1··: HnB·4 ~§-' -:;;-."" ,---·I i"',::::;j" ii'~ ,,.. -~-•-, I: 1 SUB-GRADES) V. : .......... -··1 •-·'.::..: · ' :1," ,. ~~1 ~ /i ' . __.,, ~•M::--' ., f ,iff' ~ ~,M ffi-'·"· '""' l.,..0-~. sm~rl r i?/1 ~•JU~~ rr ,u.J ''fs-!,,.' -·•~~ "-'.,_---~L~~ ' ~. ... m>, ... · ~jl ... ~ '"'fi"--'7~::!l'f'~~~~~~$i~~-../,. • I . rcY./J ' I .._ ~ .-, ----•---·• ;,~ .. 1 -APPLIED CONSULTANTS ~tot~•~ t....::·· . ' ' ~' )'o-"-, ·= [o}\rf,-:~r2·-o.-. ~1m;r.;,,,;~ 1 --=-=•...Jl--..>----1 :l-:-fill ~~lti;J!i ,,, ,:,,,1,,. ~~ , -, ~ • ""' :. ,,.. ,,.1,., • I J ~~I.N66j / < ,. • <, :,IJ r,,• '1J. ©i 'J ~'-),:ti) f,:J. ---,t-...,. , , ,f..., " '· LEGEND: Qop2-4-OLD PARALIC DEPOSITS, UNITS 6-7 ~B-1 BORING LOCATION FIGURE C: GEOLOGIC/ GEOTECHNICAL MAP (GRADING PLAN BASE) 3229 HIGHLAND DRIVE, CARLSBAD, CA 92008 jJ REFERENCE: This map was prepared from a Preliminary Site Plan by Carlos Architects and from the field investigation performed by APPLIED CONSULTANTS. Date : 7/27/23 Drawn by: JLVG REFERENCE: This figure was ---------------------------------------------1 prepared from a Preliminary -~_.., ___ _ ' -----·L. __ 1 __ _ ------ A EL. 190 -~ ____ __. ........ ...,.----.. .. \ -·--.!:. _____ _ I I r.::!:= ~-_.-,-., I Elevation by Andrew Carlos AIA and from the field investigation performed by APPLIED CONSULTANTS. A' ·-------, ------- ·-----....:.... EL.180 ~ EL. 170 :~·-·,· :,, ' . HB-1 I I ' • ·~·-·,:'·•.=-,:·_::'.·<::<>>= ::::~l:'~'.;'~~-:~<~-:/ .. :.c.-:~:x.-·: .. • ... ·., .. ·... ! I l. J ·~ :::_: 6!~~ ·~ .. SCALE: HORIZ. 1" = 1 O' VERT. 1" = 10' -APPLIED CONSULTANTS ~~~~ FIGURE D: GEOLOGIC CROSS SECTION A-A' 3229 HIGHLAND DRIVE, CARLSBAD, CA 92008 Date : 5/5/22 Drawn by: JL VG ASCE #,IRl;ANSOCIEIYCICM.~ Address: 3229 Highland Dr Carlsbad, California 92008 https://asce 7hazardtool.online/ ASCE 7 Hazards Report Standard: ASCE/SEI 7-16 Risk Category: II Soil Class: D. Stiff Soil Page 1 of 4 Elevation: 171.62 ft (NAVO 88) Latitude: 33.163373 Longitude: -117.336071 Tue Jun 14 2022 ASCE MIIDN SOCIEIYIEIM. EJ«IIIEBIS Seismic Site Soil Class: D -Stiff Soil Results: 1.044 0.379 1.083 So1 TL : PGA: NIA 8 0.459 Fv : 0.523 NIA PGAM: S,..s 1.141 1.13 FPGA S,..1 : N/A I. : 1 Sos : 0.753 Cv : 1.309 Ground motion hazard analysis may be required. See ASCE/SEI 7-16 Section 11.4.8. Data Accessed: Tue Jun 14 2022 Date Source: usGs Sejsmjc Desjgn Maps https://asce7hazardtool.online/ Page2of4 Tue Jun 14 2022 ASCE NBr.JJlSOOEIYIFIM.BallllS Flood Results: Flood Zone Categorization: X (unshaded} Base Flood Elevation: Data Source: Date Accessed: FIRM Panel: Insurance Study Note: https://asce 7hazardtool .online/ FEMA National Flood Hazard Layer -Effective Flood Hazard Layer for US, where modernized lhttps;//msc fema,goytportal/search} Tue Jun 14 2022 If available, download FIRM panel~ Download FEMA Flood Insurance Study for this area ~ Page3 of4 Tue Jun 14 2022 ASCE NIEW,M sa:EV~CM.816NBS The ASCE 7 Hazard Tool ls provided for your convenience, for informational purposes only, and Is provided •as 1s• 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. 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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 lnfonnatlon obtained therein. To the fullest extent permitted by law, you agree to release and hold harmless ASCE from any and all llablllty of any nature arising out of or resulting from any use of data provided by the ASCE 7 Hazard Tool. https:/lasce 7hazardtool.onfine/ Page 4 of4 Tue Jun 14 2022 EXPLORATORY TEST PIT LOGS 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 27 of32 Project Name: 3229 HIGHLAND DRIVE Date: ____ 5_/2_6_20_2_2 __________ _ Address: 3229 HIGHLAND DRIVE Logged By:_--'J"""L"-'V._,G==------------- CARLSBAD Reviewed By:____........, ___________ _ Location: NORTHEAST OF PROPERTY (EL. 170 FT) Footing Thickness (in.): Excavation Method: HAND AUGER Depth to Water (ft): -~N=A~-- BORING/Test Boring ID: HB-1 Sample Type: DISCRETE/BULK Caving: ______ N"-'-""O..._N=E,.__ Total De ,th ft : 3.33 De th ofFooting: NA Depth (Inches) Soil Description I-_----.-S_am_p_l_e----.----iD1·screte Bulk ,;;;-Lithology & Footing v Sample Sample Details -§ Type ID MC% Interval Interval ..S Grade-t--------------+--+----+---+---+---+----------t---'--'....i 6 12 18 24 30 36 42 48 54 60 66 72 Silty Sand (SM): fine to medium grained, loose, reddish brown silty sand. Transition to denser materia/@24" - ---- Silty Sand (SM): fine to medium grained, dense, reddish light brown silty sand. Qoe,2-4 -Old e,aralic dee,osits REFUSAL @ 40" HB-1 24"-36" HB-1 32"-40" -APPLIED CONSULTANTS BORING LOG: HB-1 3229 HIGHLAND DRIVE CARLSBAD, CA ~~-~ Roots from adjacent trees were encountered throughout the entirety of the boring DATE: 5/26/2022 Drawn By: JL VG 6 12 18 24 30 36 42 48 54 60 66 72 Project Name: 3229 IDGHLAND DRIVE Date: 5/262022 Address: 3229 HIGHLAND DRIVE Logged By: JLVG CARLSBAD Reviewed By: A.TT Location: SOUTHEAST OF PROPERTY (EL. 168 FT) Footing Thickness (in.): Excavation Method: HAND AUGER Depth to Water (ft): NA BORING/Test Boring ID: HB-2 SampleT~e: DISCRETE/BULK Caving: NONE Total Dept (ft): 4 Depth of Footing: NA Depth Sample Discrete ,......_ Bulk Lithology & Footing V) Soil Description 0 (Inches) Sample Sample ..c; Details <.> Type ID MC% Interval Interval .E Grade ._, -- ._ Silty Sand (SM): fine to medium - 6 -grained, loose, reddish brown silty 6- ._ sand . - ._ Transition to denser Roots from adjacent - 12 ._ material@ 14" trees were 12---------encountered --throughout the - 18 ._ entirety of the boring 18- ._ I --Silty Sand (SM): fine to medium -HB-2 24 -grained, dense, reddish light brown 24--silty sand. 18"-30" Unable to retrieve - ._ ring samples - 30 -30- -- -- 36 -36- -Qoe.2-4 -Old e.aralic dee.osits - -- 42 -42- -- -- 48 48- -TERMINATED @ 48" --- 54 ._ 54- ._ --- 60 -60- ._ - ._ - 66 -66--- -- 72 -72- -APPLlED BORING LOG: HB-2 DATE: 5/26/2022 3229 HIGHLAND DRIVE Drawn By: JLVG CONSULTANTS CARLSBAD, CA .,...__...,...,,.. ~ Project Name: 3229 HIGHLAND DRIVE Date: ___ ..::;.5:..:/2:..::c6:c20=-=2=2 __________ _ Address: 3229 HIGHLAND DRIVE Logged By: _ _,J=L"-'V'""'G"------------- CARLSBAD Reviewed By:__.,,,,.,_. ___________ _ Location: WEST OF PROPERTY (EL. 164 FTI Footing Thickness (in.): Excavation Method: HAND AUGER Depth to Water (ft): -~N~A~-- BORING/Test Boring ID: HB-3 Sample Type: DISCRETE/BULK Caving: ______ N~O~N=E~_ Total De 1th ft : 4 De th of Footing: NA Depth (Inches) Soil Description 1-----.-S_am_p_l_e---r----iDiscrete Bulk ype ID Sample Sample MC% Interval Interval Lithology & Footing Details ,-.. U) "5 C C Grade-+-------------t---t-----t----t-----t----r----------i---.1 6 12 18 24 30 36 42 Silty Sand (SM): fine to medium grained, loose, reddish brown silty sand. Transition to denser materia/@24" Silty Sand (SM): fine to medium grained, dense, reddish light brown silty sand. Qop2-4 -Old para/ic deposits HB-3 28"-40" 481---------------· TERMINATED @ 48" 54 60 66 72 .APPLIED CONSULTANTS ~,..,., . ..,_...., BORING LOG: HB-3 3229 HIGHLAND DRIVE CARLSBAD, CA Roots from adjacent trees were encountered throughout the entirety of the boring Roots found in ring samples DATE: 5/26/2022 Drawn By: JL VG 6 12 18 24 30 36 42 48 54 60 66 72 Project Name: 3229 HIGHLAND DRIVE Date: ___ ...::;5.:..::/2=-=6=-20:::..::2::::2:...._ _________ _ Address: 3229 HIGHLAND DRIVE Logged By: __ J=L._V:....:G,.__ __________ _ CARLSBAD Reviewed By:___.....u..'------------- Location: SOUTH OF PROPERTY/CARPORT(EL. 158 FT) Footing Thickness (in.): Excavation Method: HAND AUGER BORING/Test Boring ID: HB-4 Sample Type: DISCRETE/BULK Total De 1th ft : 4 Depth to Water (ft): _ _._N.,_._._ __ Caving: -------'-'-""NO'-'-N,.,.E"---- De th of Footing: NA Depth (Inches) Soil Description 1--~-S_am_pl_e~-~ Discrete Bulk Lithology & Footing Details ,...._ ~ i:: C Grade-+-------------+---+----+---+----+---+---------+-----ri Sample Sample MC% Interval Interva Type ID 6 12 18 24 30 36 48 54 60 66 72 Silty Sand (SM): fine to medium grained, loose, reddish brown silty sand. Transition to denser materia/@24" Silty Sand (SM): fine to medium grained, dense, reddish light brown silty sand. Qop2-4 -Old paralic deposits TERMINATED@42" HB-4 30"-42" -APPLIED CONSULTANTS BORING LOG: HB-4 3229 HIGHLAND DRIVE CARLSBAD, CA .,.._...~~~ Roots from adjacent trees were encountered throughout the entirety of the boring DATE: 5/26/2022 Drawn By: JL VG 6 12 18 24 30 36 42 48 54 60 66 72 GENERAL EARTHWORK AND GRADING GUIDELINES 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 28 of32 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. II. PREPARATION OF AREAS TO BE FILLED 1. Clearing and Grubbing: All brush, vegetation, and debris shall be removed and properly disposed of. The Geotechnical Consultant shall evaluate the extent of removal of these items depending on site conditions. Fill material shall not contain more than 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. 3229 Highland Drive- Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 29 of32 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. 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 COMP ACTION 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. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 30 of32 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. 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. VII. TRENCH BACKFILL 1. The Contractor shall follow all OSHA and CAL/OSHA 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. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 31 of32 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. 3229 Highland Drive-Updated Preliminary Geotechnical Investigation JLVG/JED 7/27/2023 Page 32 of32