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Home My WebLink AboutCD 2020-0022; THE BEACON PHASE 3; GEOTECHNICAL EVALUATION LA COSTA TOWNE CENTER TENANT IMPROVEMENTS; 2015-04-17 November 10, 2021 Project No. 9407.1 Log No. 21673 City of Carlsbad Land Development Engineering 1635 Faraday Avenue Carlsbad, California 92008-7314 Attention: Mr. David Rick Subject: THIRD-PARTY GEOTECHNICAL REVIEW (SECOND) Proposed Improvements 7760 & 7770 El Camino Real Carlsbad, California Project ID: CD 2020-0022/GR 2021-0024 References: Attached Dear Mr. Rick: In accordance with your request, Hetherington Engineering, Inc. has provided third-party geotechnical review of Reference 5. Based on our review, the Geotechnical Consultant has responded to our prior comments and we have no additional comments. Observation and testing by the Geotechnical Consultant during grading and construction should be required to verify anticipated conditions or to revise the geotechnical recommendations as considered necessary. A final geotechnical report of grading and construction should be required. The opportunity to be of service is sincerely appreciated. If you have any questions regarding this review, please contact this office at your convenience. Sincerely, HETHERINGTON ENGINEERING, INC. Mark D. Hetherington Civil Engineer 30488 Geotechnical Engineer 397 (expire 3/31/22) Distribution: 1-via e-mail (David.Rick@carlsbadca.gov) 1-via e-mail (LDETrackingdesk@carlsbadca.gov) SOIL & FOUNDATION ENGINEERING ENGINEERING GEOLOGY HYDROGEOLOGY (760) 931-1917 Fax (760) 931-0545 333 Third Street Laguna Beach, CA 92651 (949) 715-5440 Fax (949) 715-5442 Carlsbad, CA 92008-43695365 Avenida Encinas, Suite A HETHERINGTON ENGINEERING, INC. www.hetheringtonengineering.com Project No. 9407.1 Log No. 21673 REFERENCES 1. “Geotechnical Evaluation, La Costa Towne Center Tenant Improvements, El Camino Real and La Costa Avenue, Carlsbad, California,” by Ninyo & Moore, dated April 17, 2015. 2. “Grading Plans for: The Beacon Phase 3, 7760 & 7770 El Camino Real,” by Blue Peak Engineering, Inc., dated May 25, 2021. (Sheets 1 through 4). 3. “Third-Party Geotechnical Review (First), Proposed Improvements, 7760 & 7770 El Camino Real, Carlsbad, California, Project ID: CD 2020-0022/GR 2021-0024”, by Hetherington Engineering Inc., dated July 14, 2021. 4. “Response to Third-Party Review and Plan Review, The Beacon La Costa – Phase 3, 7760 and 7770 El Camino Real, Carlsbad”, by Ninyo & Moore, dated September 13, 2021. (2 Documents) 5. “Update Geotechnical Evaluation, The Beacon La Costa – Phase 3, 7760 and 7770 El Camino Real, Carlsbad, California”, by Ninyo & Moore, dated September 3, 2021. HETHERINGTON ENGINEERING, INC. GEOTECHNICAL EVALUATION LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA PREPARED FOR: AG-CP La Costa Owner, LP 1640 5th Street, Suite 101 Santa Monica, California 90401 PREPARED BY: Ninyo & Moore Geotechnical and Environmental Sciences Consultants 5710 Ruffin Road San Diego, California 92123 April 17, 2015 Project No. 107302005 La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc i TABLE OF CONTENTS Page 1. INTRODUCTION....................................................................................................................1 2. SCOPE OF SERVICES............................................................................................................1 3. SITE AND PROJECT DESCRIPTION ...................................................................................2 4. SUBSURFACE EXPLORATION AND LABORATORY TESTING....................................3 5. SURFACE CONDITIONS.......................................................................................................3 6. GEOLOGY AND SUBSURFACE CONDITIONS.................................................................4 6.1. Regional Geologic Setting............................................................................................4 6.2. Site Geology.................................................................................................................4 6.2.1. Fill.......................................................................................................................5 6.2.2. Possible Landslide Deposits................................................................................5 6.2.3. Delmar Formation...............................................................................................5 6.3. Groundwater.................................................................................................................5 7. GEOLOGIC HAZARDS..........................................................................................................6 7.1. Faulting and Seismicity................................................................................................6 7.1.1. Ground Motion....................................................................................................6 7.1.2. Liquefaction Induced Settlement........................................................................7 7.2. Tsunamis.......................................................................................................................7 7.3. Landslides.....................................................................................................................8 8. CONCLUSIONS ......................................................................................................................8 9. RECOMMENDATIONS..........................................................................................................9 9.1. Earthwork and Site Preparation....................................................................................9 9.1.1. Excavation Characteristics..................................................................................9 9.1.2. Excavation and Shoring....................................................................................10 9.1.3. Materials for Fill ...............................................................................................10 9.1.4. Compacted Fill..................................................................................................11 9.1.5. Pipe Bedding and Modulus of Soil Reaction (E').............................................12 9.1.6. Utility Trench Backfill......................................................................................12 9.1.7. Site Drainage.....................................................................................................13 9.2. Seismic Design Parameters.........................................................................................13 9.3. Foundations.................................................................................................................14 9.3.1. Allowable Bearing Capacity.............................................................................14 9.3.2. Foundation Lateral Resistance..........................................................................15 9.4. Retaining Walls ..........................................................................................................15 9.5. Flexible Pavements.....................................................................................................16 9.6. Concrete Flatwork ......................................................................................................17 9.7. Concrete......................................................................................................................17 9.8. Pre-Construction Meeting...........................................................................................18 9.9. Plan Review and Construction Observation...............................................................18 La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc ii 10. LIMITATIONS.......................................................................................................................19 11. REFERENCES.......................................................................................................................21 Tables Table 1 – 2013 California Building Code Seismic Design Criteria...............................................14 Table 2 – Recommended Preliminary Flexible Pavement Sections ..............................................16 Figures Figure 1 – Site Location Figure 2 – Project Area Figure 3 – Boring Locations Figure 4 – Geology Figure 5 – Fault Locations Figure 6 – Lateral Earth Pressures for Yielding Retaining Walls Figure 7 – Lateral Earth Pressures for Restrained Retaining Walls Figure 8 – Retaining Wall Drainage Detail Appendices Appendix A – Boring Logs Appendix B – Laboratory Testing La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 1 1. INTRODUCTION In accordance with our proposal dated February 18, 2015, we have prepared this geotechnical evaluation for the proposed tenant improvements to the existing La Costa Towne Center. The pro- ject is located at the southeast corner of El Camino Real and La Costa Avenue in the city of Carlsbad, California (Figure 1). The renovation of the existing building at 7710 El Camino Real is addressed in a separate report. This report summarizes our geotechnical work at the site, presents conclusions regarding the geotechnical conditions at the project site, and makes recommendations regarding design and construction of the currently proposed project. 2. SCOPE OF SERVICES Our scope of services included the following:  Reviewing background information including available geotechnical reports (including previ- ous site geotechnical reports), as-built plans, geologic and fault maps, and aerial photographs.  Performing a geologic reconnaissance of the subject site.  Marking the exploratory boring locations for clearance by Underground Service Alert.  Coordinating with the County of San Diego Department of Environmental Health (DEH) to obtain boring permits.  Performing a subsurface exploration consisting of the drilling and logging of six exploratory soil borings with a limited-access drill rig equipped with hollow stem augers (B-1 through B-3) or manual techniques (HA-1 through HA-3). The borings were advanced to depths up to 30.8 feet.  Collecting bulk and in-place soil samples at selected depths from the soil borings and trans- porting them to our in-house geotechnical laboratory for analysis.  Performing geotechnical laboratory testing on representative samples collected during our subsurface exploration.  Compiling and analyzing the data obtained from our research, subsurface exploration, and geotechnical laboratory testing.  Preparing this report presenting our findings, conclusions, and recommendations regarding geotechnical design and construction aspects of the project. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 2 3. SITE AND PROJECT DESCRIPTION The project site is an existing shopping center at the southeast corner of El Camino Real and La Costa Avenue in Carlsbad, California (Figure 2). The shopping center is comprised of a large, single-story anchor structure at the north end of the site with six, one-story and two-story retail structures in the central and southern portions of the site. Further improvements include the shop- ping center’s main parking lot and an upper parking lot are separated by a vegetated slope with a roughly north-south trending concrete masonry unit (CMU) retaining wall approximately 4 feet high. Additional parking areas are located between the central retail structures and along the east- erly edge of the site. Also, roughly north-south trending CMU retaining walls approximately 3 feet high are also present at the eastern and western perimeters of the site. Another approximately 8-foot high retaining wall is situated to the north of the anchor structure. Elevations at the site range from approximately 40 feet above mean sea level (MSL) at the northwestern corner of the site along El Camino Real to approximately 80 feet at the northeast portion of the site. A previous geotechnical investigation performed by Benton Engineering (1977), concluded that an old landslide was present at the site on the eastern slope descending towards the shopping center and rec- ommendations were provided for mitigation of the landslide. Based on the reviewed as-built grading plans for the site (Brian Smith Engineers, 1982), landslide remediation measures were implemented at the time of the construction of the shopping center and included the construction of cast-in-place shear pins and buttress fills placed along the hillside east of the shopping center. Based on our review of the data and our subsurface exploration, the landslide does not extend into the tenant improvement area. Based on our review of the preliminary project plans (Mour, 2015), we understand that the pro- posed project will include minor tenant improvements and additions to the shopping center including new awnings, covered walkways, screen walls and site walls. Additional improvements are anticipated to include additional underground utilities and new concrete and asphalt con- crete (AC) pavements. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 3 4. SUBSURFACE EXPLORATION AND LABORATORY TESTING Our subsurface exploration was conducted on March 12 and 16, 2015, and consisted of excavat- ing six exploratory borings (B-1 through B-3 and HA-1 through HA-3). Borings B-1 through B- 3 were excavated using a limited access drill rig within the anchor structure to depths up to ap- proximately 31 feet. Borings HA-1 through HA-2 were manually excavated using hand tools to depths up to approximately 4 feet. The borings were logged by representatives from our firm. Representative in-place and bulk soil samples were obtained at selected depths from each of the borings for laboratory testing. The approximate locations of the borings are presented on Fig- ure 3. The boring logs are presented in Appendix A. Relatively undisturbed and bulk samples were collected at selected depths from the borings and were transported to our laboratory for geotechnical testing. Laboratory testing for the tenant im- provements project included Atterberg Limits and R-value. The results of the laboratory tests performed are presented in Appendix B. 5. SURFACE CONDITIONS As part of our evaluation, we performed a field reconnaissance of the site to observe the existing conditions. In general, our reconnaissance included observations of the existing the asphalt con- crete (AC) within the parking areas and drive aisles, the existing retaining walls, and the existing slopes. At various locations within the site the existing AC pavements exhibited features consist- ing of alligator cracking, joint cracking, raveling, and potholing. As described earlier, there are various retaining walls at the project site. Some portions of the relatively short retaining walls along the easterly portion of the site exhibit a slight tilt. Also, due to the presence of weep holes, water is seeping through these weep holes onto the existing pave- ment surface. Additionally, water was observed to be seeping through portions of the face of the slopes along the east side of the project site. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 4 Also, the retaining wall to the north of the anchor structure has shown indications of bulging. However, this retaining wall is part of the adjacent property to the north. Accordingly, we under- stand that the property owner to the north will address this wall condition. 6. GEOLOGY AND SUBSURFACE CONDITIONS Our findings regarding regional and site geology, including faulting and seismicity, landslides, and groundwater conditions are provided in the following sections. 6.1. Regional Geologic Setting The project area is located in the western San Diego County section of the Peninsular Ranges Geomorphic Province. This geomorphic province encompasses an area that extends approximately 900 miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja California (Norris and Webb, 1990). The province varies in width from approximately 30 to 100 miles. In general, the province consists of rugged mountains underlain by Jurassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks of the southern California batholith. The portion of the province in San Diego County that includes the project area consists generally of Quaternary-age surficial deposits, under- lain by Tertiary- and Cretaceous-age sedimentary rocks. 6.2. Site Geology As shown on Figure 4, the project site is generally underlain by the Tertiary-age Delmar Formation. Surficial soils consisting of fill materials and possible landslide deposits are also present in the project area. Generalized descriptions of the on-site materials are provided be- low. Additional descriptions are provided on the boring logs (Appendix A). La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 5 6.2.1. Fill Fill soils were encountered in each of our borings underlying the interior concrete slab- on-grade for the building or beneath AC pavements to depths up to approximately 4 feet. As encountered, the fill materials generally consisted of various shades of brown and gray, moist, medium dense, silty to clayey sand and firm to hard, silty clay. 6.2.2. Possible Landslide Deposits As discussed in the Benton report (Benton, 1977), landslide deposits underlie portions of the La Costa Towne Center site. The possible landslide deposits generally consist of material derived from the Delmar Formation. The landslide deposits were not encoun- tered in our borings and are not anticipated to underlie the area of the proposed tenant improvements. 6.2.3. Delmar Formation Materials of the Tertiary-age Delmar Formation were encountered in borings B-1 through B-3 underlying the fill materials to the total depths explored. These materials generally consisted of various shades of olive and gray, dry to moist, weakly to moder- ately indurated, clayey siltstone and moderately to strongly cemented sandy siltstone and silty sandstone. Scattered concretions or very strongly cemented zones are antici- pated to be encountered within the Delmar Formation. 6.3. Groundwater Groundwater was not encountered in our exploratory borings. However, groundwater result- ing from seepage of upslope irrigation has been measured at depths as shallow as 3½ feet in previous borings performed in the project area. Fluctuations in the groundwater level may occur due to variations in tidal fluctuations, ground surface topography, subsurface geologic conditions and structure, rainfall, irrigation, and other factors. The piezometers at the site should continue to be monitored as the project moves towards construction. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 6 7. GEOLOGIC HAZARDS The following sections describe potential geologic hazards at the site, including faulting and seismicity, landsliding, and liquefaction. 7.1. Faulting and Seismicity The subject site is considered to be in a seismically active area. Our review of readily avail- able published geological maps and literature indicate that the there are no known active or potentially active faults (i.e., faults that exhibit evidence of ground displacement in the last 11,000 years and 2,000,000 years, respectively), underlying the proposed site. Major known active faults in the region consist generally of en-echelon, northwest-striking, right-lateral, strike-slip faults. These include the San Andreas, Elsinore, and San Jacinto faults located northeast of the site, and the San Clemente, San Diego Trough, and Coronado Bank faults located to the west of the site (Figure 5). The closest known active fault is the Rose Canyon Fault, which can generate an earthquake magnitude of up to 7.2 (Cao et al., 2003), is located approximately 5 miles west of the site. In general, hazards associated with seismic activity include strong ground motion, ground surface rupture, liquefaction, and seismically induced settlement. Discussion of these con- siderations is included in the following sections. 7.1.1. Ground Motion The 2013 California Building Code (CBC) specifies that the Risk-Targeted, Maximum Considered Earthquake (MCER) ground motion response accelerations be used to evaluate seismic loads for design of buildings and other structures. The MCER ground motion response accelerations are based on the spectral response accelerations for 5 percent damping in the direction of maximum horizontal response and incorporate a target risk for structural collapse equivalent to 1 percent in 50 years with deterministic limits for near-source effects. The horizontal peak ground acceleration (PGA) that corresponds to the MCER for the site was calculated as 0.46g using the United States La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 7 Geological Survey (USGS, 2013) seismic design tool (web-based). Spectral response acceleration parameters, consistent with the 2013 CBC, are also provided in Section 9.2 for the evaluation of seismic loads on buildings and other structures. The 2013 CBC specifies that the potential for liquefaction and soil strength loss be evaluated, where applicable, for the Maximum Considered Earthquake Geometric Mean (MCEG) peak ground acceleration with adjustment for site class effects in accordance with the American Society of Civil Engineers (ASCE) 7-10 Standard. The MCEG peak ground acceleration is based on the geometric mean peak ground acceleration with a 2 percent probability of exceedance in 50 years. The MCEG peak ground acceleration with adjustment for site class effects (PGAM) was calculated as 0.46g using the USGS (USGS, 2013) seismic design tool that yielded a mapped MCEG peak ground acceleration of 0.43g for the site and a site coefficient (FPGA) of 1.074 for Site Class D. 7.1.2. Liquefaction Induced Settlement Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earth- quakes. Research and historical data indicate that loose, granular soils with clay contents of less than 20 percent, which are saturated by a relatively shallow groundwater table, are more susceptible to liquefaction. However, based on the generally dense nature of the formational materials underlying the site, the potential for liquefaction at the site is not a design consideration. 7.2. Tsunamis Tsunamis are long wavelength seismic sea waves (long compared to the ocean depth) gener- ated by sudden movements of the ocean bottom during submarine earthquakes, landslides, or volcanic activity. Based on the elevations of the existing grade of the project site (i.e., ap- proximately 40 to 80 feet MSL), and the distance from the ocean, the potential for tsunamis affecting the site is not a design consideration. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 8 7.3. Landslides Based on our review of referenced geologic maps, there are no mapped landslides underlying the site of the proposed tenant improvements. However, the previous evaluation of the site per- formed by Benton (1977), indicated that an ancient landslide was present east of the site of the proposed tenant improvements based on the presence of claystone and siltstones with slicken- sided surfaces indicating shearing. 8. CONCLUSIONS Based on the results of our background review, subsurface exploration, laboratory testing, and data analysis, construction of the proposed improvements is feasible from a geotechnical stand- point, provided the recommendations of this report are incorporated in the design and construction of the project. Geotechnical considerations include the following:  Based on the evidence presented herein, it is our opinion that active faults are not present on or adjacent to the project site.  Based on the findings from this evaluation and our background research, it is our opinion that possible landslide debris is not present beneath the structures.  The subsurface conditions encountered at the site during our subsurface exploration corre- spond to Site Class D.  The on-site materials are generally excavatable with conventional heavy-duty earth moving construction equipment. However, strongly cemented zones within the formational materials were encountered that may require additional effort in excavation. Additionally, existing fill soils are susceptible to caving and sloughing. Zones of seepage will also exacerbate the cav- ing of on-site soils.  Due to the presence of zones of seepage, the contractor should anticipate encountering wet soils that will require additional moisture-conditioning and aeration prior to reuse as compacted fill.  As a result of the presence of wet soils and zones of seepage the contractor should anticipate encountering yielding subgrade conditions that will require additional processing and/or sta- bilization.  Based on our experience at the site and the close proximity to a lagoonal environment, the site soils should be considered corrosive. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 9  Due to the observed features with the AC pavements and site retaining walls, we anticipate that some of these areas may need to be reconstructed.  We understand that the condition of the retaining wall north of the anchor structure will be addressed by the property owner to the north.  Due to the presence of water seepage onto pavements from the weep holes from site retain- ing walls, additional surface water conveyance systems should be incorporated into the site improvements to drain water from the surface pavements. 9. RECOMMENDATIONS Based on our understanding of the project, the following recommendations are provided for the design and construction of the proposed tenant improvements. The proposed site improvements should be constructed in accordance with the requirements of the applicable governing agencies. Please note, renovation of the building at 7710 El Camino Real is addressed in a separate report. 9.1. Earthwork and Site Preparation Earthwork at the site is anticipated to include removal of existing site improvements, and grad- ing associated with installation of associated improvements including new foundations for tenant improvements, utilities, pavements, driveways, and concrete flatwork. Earthwork opera- tions should be performed in accordance with the requirements of applicable governing agencies and the recommendations presented in the following sections of this report. Ninyo & Moore should be contacted for questions regarding the recommendations presented herein. 9.1.1. Excavation Characteristics In our opinion, the on-site materials are generally expected to be excavatable with conventional heavy-duty earthmoving equipment. However, as noted, strongly cemented zones requiring additional effort should be expected in excavations within the formational materials. Excavations may generate oversize material that may not be suitable for use as fill. Excavations within fill materials and possible landslide debris are prone to caving and sloughing. Also, the contractor should anticipate encountering wet materials in excavations for utilities. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 10 9.1.2. Excavation and Shoring We recommend that trenches and excavations be designed and constructed in accordance with Occupational Safety and Health Administration (OSHA) regulations. These regula- tions provide trench sloping and shoring design parameters for trenches up to 20 feet deep based on a description of the soil types encountered. Trenches over 20 feet deep should be designed by the Contractor’s engineer based on site-specific geotechnical analyses. For planning purposes, we recommend that the following OSHA soil classifications be used: Fill Materials, Possible Landslide Debris Type C Delmar Formation Type B Temporary excavations should be constructed in accordance with OSHA recommenda- tions. The Delmar Formation contains concretions, which will impact excavating, drilling, and trenching operations. For trench or other excavations, OSHA requirements regarding personnel safety should be met by laying back the slopes no steeper than 1.5:1 (horizontal to vertical) for fill and possible landslide debris and 1:1 for mate- rials of the Delmar Formation. Temporary excavations that encounter seepage may be stabilized by placing sandbags or gravel along the base of the seepage zone. Excava- tions encountering seepage should be evaluated on a case-by-case basis. As an alternative to laying back the side walls, the excavations may be shored or braced. 9.1.3. Materials for Fill On-site soils with an organic content of less than 3 percent by volume (or 1 percent by weight) are generally considered suitable for reuse as general fill. However, from our previ- ous experience at the site, some of the on-site soils may possess a medium potential for expansion. Fill material should not contain rocks or lumps over 6 inches in largest dimension, and not more than 30 percent larger than 3/4 inch. Utility trench backfill material should not contain rocks or lumps over 3 inches in largest dimension. Larger chunks, if generated during excavation, may be broken into acceptably sized pieces or disposed of off site. Imported fill material should be a low or very low expansion potential (Expansion Index [EI] of 50 or less) granular soil. Import material should also have low corrosion potential (resistivity of La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 11 1,000 ohm centimeters or more, chloride content less than 500 parts per million [ppm], solu- ble sulfate content of less than 0.1 percent, and pH of 5.5 or more). Materials for use as fill should be evaluated by a Ninyo & Moore representative prior to filling or importing. 9.1.4. Compacted Fill Prior to placement of compacted fill, the contractor should request an evaluation of the ex- posed ground surface by Ninyo & Moore. Unless otherwise recommended, the exposed ground surface should then be scarified to a depth of approximately 8 inches and watered or dried, as needed, to achieve generally consistent moisture contents at or near the opti- mum moisture content. The scarified materials should then be compacted to 90 percent relative compaction as evaluated by the ASTM International (ASTM) Test Method D 1557. The evaluation of compaction by Ninyo & Moore should not be considered to preclude any requirements for observation or approval by governing agencies. It is the contractor's re- sponsibility to notify Ninyo & Moore and the appropriate governing agency when project areas are ready for observation, and to provide reasonable time for that review. Fill materials should be moisture-conditioned to near optimum moisture content prior to placement. The optimum moisture content will vary with material type and other factors. Moisture-conditioning of fill soils should be generally consistent within the soil mass. Prior to placement of additional compacted fill material following a delay in the grading operations, the exposed surface of previously compacted fill should be prepared to receive fill. Preparation may include scarification, moisture-conditioning, and recompaction. Compacted fill should be placed in horizontal lifts of approximately 8 inches in loose thickness. Prior to compaction, each lift should be watered or dried as needed to achieve near optimum moisture condition, mixed, and then compacted by mechanical methods to a relative compaction of 90 percent as evaluated by ASTM D 1557. Successive lifts should be treated in a like manner until the desired finished grades are achieved. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 12 9.1.5. Pipe Bedding and Modulus of Soil Reaction (E') It is our recommendation that the new pipeline (pipes), where constructed in open excava- tions, be supported on 6 or more inches of granular bedding material. Granular pipe bedding should be provided to distribute vertical loads around the pipe. Bedding material and compaction requirements should be in accordance with this report. Pipe bedding typi- cally consists of graded aggregate with a coefficient of uniformity of three or more. The pipe bedding should conform to the specifications presented for pipe zone backfill materi- als. Soils classified as silts or clays should not be used for backfill in the pipe zone. Pipe bedding and pipe zone backfill should have a Sand Equivalent of 30 or more, and be placed around the sides and the crown of the pipe. In addition, the pipe zone backfill should extend 1 foot or more above the crown of the pipe. If open-graded gravel is used as pipe zone backfill, we recommend that the pipe bedding and pipe zone materials be wrapped along to bottom, top, and sides in a non-woven geotextile fabric. The modulus of soil reaction (E') is used to characterize the stiffness of soil backfill placed at the sides of buried flexible pipes for the purpose of evaluating deflection caused by the weight of the backfill over the pipe (Hartley and Duncan, 1987). A soil reaction modulus of 1,200 pounds per square inch (psi) may be used for design provided that granular bedding material is placed adjacent to the pipe, as recommended in this report. 9.1.6. Utility Trench Backfill Based on our subsurface exploration, the on-site earth materials may be suitable for re- use as utility trench zone backfill provided they are free of organic material, clay lumps, debris, and rocks greater than approximately 3 inches in diameter. Trench backfill should be moisture-conditioned to generally above the laboratory optimum. Lift thick- ness for backfill will depend on the type of compaction equipment utilized, but fill should generally be placed in lifts not exceeding 8 inches in loose thickness. Special care should be exercised to avoid damaging the pipe during compaction of the backfill. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 13 9.1.7. Site Drainage Roof, pad, and slope drainage should be diverted away from slopes and structures to suit- able discharge areas by nonerodible devices (e.g., gutters, downspouts, concrete swales, etc.). Positive drainage adjacent to structures should be established and maintained. Posi- tive drainage may be accomplished by providing drainage away from the foundations of the structure at a gradient of 2 percent or steeper for a distance of 5 feet outside the building perimeter, and further maintained by a graded swale leading to an appropriate outlet, in ac- cordance with the recommendations of the project civil engineer and/or landscape architect. Surface drainage on the site should be provided so that water is not permitted to pond. A gradient of 2 percent or steeper should be maintained over the pad area and drainage pat- terns should be established to divert and remove water from the site to appropriate outlets. Care should be taken by the contractor during grading to preserve any berms, drainage terraces, interceptor swales or other drainage devices on or adjacent to the property. Drainage patterns established at the time of grading should be maintained for the life of the project. The property operators should be made very clearly aware that altering drainage patterns might be detrimental to slope stability and foundation performance. Also, the weep holes from existing site retaining walls drain onto site pavements. De- sign considerations to convey water off the surface of pavements should be incorporated into the site design. 9.2. Seismic Design Parameters Design of the proposed improvements should be performed in accordance with the requirements of governing jurisdictions and applicable building codes. Table 1 presents the seismic design parameters for the site in accordance with the CBC (2013) guidelines and adjusted MCER spectral response acceleration parameters (USGS, 2013). La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 14 Table 1 – 2013 California Building Code Seismic Design Criteria Site Coefficients and Spectral Response Acceleration Parameters Values Site Class D Site Coefficient, Fa 1.068 Site Coefficient, Fv 1.583 Mapped Spectral Response Acceleration at 0.2-second Period, Ss 1.080 g Mapped Spectral Response Acceleration at 1.0-second Period, S1 0.417 g Spectral Response Acceleration at 0.2-second Period Adjusted for Site Class, SMS 1.153 g Spectral Response Acceleration at 1.0-second Period Adjusted for Site Class, SM1 0.660 g Design Spectral Response Acceleration at 0.2-second Period, SDS 0.769 g Design Spectral Response Acceleration at 1.0-second Period, SD1 0.440 g 9.3. Foundations Based on our understanding of the project, it is anticipated that the proposed tenant improve- ments may be supported on either shallow continuous or spread footings. The following foundation design parameters are provided based on our preliminary analysis. The foundation design parameters are not intended to preclude differential movement of soils. Minor cracking (considered tolerable) of foundations may occur. Foundations recommendations for the reno- vation of the building at 7710 El Camino Real is addressed in a separate report. 9.3.1. Allowable Bearing Capacity Foundations for new tenant improvements may be founded on either shallow continu- ous or spread footings using an allowable bearing capacity of 3,000 psf for foundations bearing on compacted fill or competent materials of the Delmar Formation. This allow- able bearing capacity may be increased by one-third when considering loads of a short duration such as wind or seismic forces. From a geotechnical standpoint, spread or con- tinuous footings should have an embedment depth of 18 inches. Continuous footings should have a width of 18 inches or more and isolated footings should be 24 inches or more in width. Thickness and reinforcement of the foundations should be in accordance with the recommendations of the project structural engineer. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 15 9.3.2. Foundation Lateral Resistance For resistance to lateral loads, an allowable passive pressure exerted by an equivalent fluid weight of 300 pounds per cubic foot (pcf) may be used for foundations embedded in com- pacted fill or competent materials of the Delmar Formation. This value assumes that the ground is horizontal for a distance of 10 feet or more, or three times the height generating the passive pressure, whichever is greater. For 2:1 descending slope conditions, an allow- able passive pressure exerted by an equivalent fluid weight of 140 pcf may be used. We recommend that the upper 1 foot of soil not protected by pavement or a concrete slab be neglected when calculating passive resistance. For frictional resistance to lateral loads, we recommend a coefficient of friction of 0.3 be used between soil and concrete. If passive pressure and frictional resistance are to be used in combination, we recommend that the friction coefficient be reduced by two- thirds. The passive pressure values may be increased by one-third when considering loads of short duration such as wind or seismic forces. 9.4. Retaining Walls As described earlier, portions of some of the site retaining walls have a slight tilt. These por- tions of the retaining walls may need to be replaced. In areas where a new retaining wall is to be constructed, we recommend the design of a yielding retaining wall that is not re- strained against movement by rigid corners or structural connections, lateral pressures are presented on Figure 6. Restrained walls (non-yielding) may be designed for lateral pressures presented on Figure 7. These pressures assume low-expansive backfill and free draining conditions. Measures should be taken to reduce the potential for build-up of moisture behind the retaining walls. A drain should be provided behind the retaining wall as shown on Fig- ure 8. The drain should be connected to an appropriate outlet. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 16 9.5. Flexible Pavements During our subsurface exploration we encountered pavements sections with AC thicknesses ranging from approximately 2½ to 4¾ inches thick. The AC was then underlain by a subbase material with a thickness range of approximately 0 to 8 inches. Additionally we observed various pavement areas within the project site exhibited signs of alligator cracking, joint cracking, raveling, and potholing. Accordingly, we anticipate that some new AC pavement sections will be constructed at the site. Our laboratory testing indicated R-values of 32, 34, and 44 for site soils. Based on the re- sults of our laboratory testing, subsurface exploration and our experience with soils similar to those encountered at and near the site, we have used an R-value of 30 for the preliminary basis for design of flexible pavements at the project site. Actual pavement recommendations should be based on R-value tests performed on bulk samples of the soils that are exposed at the finished subgrade elevations across the site during paving operations. We understand that traffic will consist primarily of automobiles, delivery trucks, garbage trucks, and fire service vehicles. For design, we have assumed Traffic Indices (TI) of 5.0, 6.0, and 7.0 for site pavements. We have also used the City of Carlsbad (2004) Engineering Standards in our design. The preliminary recommended pavement sections are as follows: Table 2 – Recommended Preliminary Flexible Pavement Sections Traffic Index Design R-Value Asphalt Concrete (in) Class 2 Aggregate Base (in) 5.0 30 4 4 6.0 30 4 7 7.0 30 4 10 It is recommended that the upper 12 inches of the subgrade and base materials be compacted to a relative compaction of 95 percent as evaluated by ASTM D 1557. We recommend that asphalt concrete be compacted to 95 percent relative compaction as compared to the mate- rial’s Hveem density. Ninyo & Moore should re-evaluate the pavement design based on La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 17 actual TI values of the subject pavement areas and the R-value of the subgrade material ex- posed at the time of construction. We suggest that consideration be given to using Portland cement concrete pavements in areas where dumpsters will be stored and where refuse trucks will stop and load. Experience indi- cates that refuse truck traffic can significantly shorten the useful life of AC sections. We recommend that in these areas, 7½ inches of 600 pounds per square inch (psi) flexural strength Portland cement concrete reinforced with No. 3 bars, 18-inches on center, be placed over 6 inches or more of aggregate base materials compacted to a relative compaction of 95 percent. 9.6. Concrete Flatwork Exterior concrete flatwork should be 4 inches in thickness and should be reinforced with No. 3 reinforcing bars placed at 24 inches on-center both ways. Exterior slabs should be un- derlain by 4 inches of clean sand. A vapor retarder is not needed for exterior flatwork. To reduce the potential manifestation of distress to exterior concrete flatwork due to movement of the underlying soil, we recommend that such flatwork be installed with crack-control joints at appropriate spacing as designed by the structural engineer. Before placement of concrete, the subgrade soils should be scarified to a depth of 8 inches, moisture conditioned to generally above the laboratory optimum moisture content, and compacted to a relative compaction of 90 percent as evaluated by ASTM D 1557. Positive drainage should be estab- lished and maintained adjacent to flatwork. 9.7. Concrete Due to the close proximity of the site to a lagoonal environment, we consider the site soils to be corrosive, we recommend that Type V cement be used for concrete structures in contact with soil. In addition, we recommend that concrete in contact with soil possess a compres- sive strength of 4,500 psi and a water to cement ratio of no more than 0.45. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 18 In order to reduce the potential for shrinkage cracks in the concrete during curing, we rec- ommend that the concrete for proposed structures, be placed with a slump of 4 inches based on ASTM C 143. The slump should be checked periodically at the site prior to concrete placement. We also recommend that crack control joints be provided in slabs in accordance with the recommendations of the structural engineer to reduce the potential for distress due to minor soil movement and concrete shrinkage. We further recommend that concrete cover over reinforcing steel for foundations be provided in accordance with ACI 318. The struc- tural engineer should be consulted for additional concrete specifications. 9.8. Pre-Construction Meeting We recommend that a pre-construction meeting be held prior to commencement of grading. The owner or his representative, the agency representatives, the architect, the civil engineer, Ninyo & Moore, and the contractor should be in attendance to discuss the plans, the project, and the proposed construction schedule. 9.9. Plan Review and Construction Observation Ninyo & Moore should review the final project drawings and specifications prior to the commencement of construction. Our design recommendations may be modified depending on our plan review details. Ninyo & Moore should perform the needed observation and testing services during con- struction operations. In the event that it is decided not to utilize the services of Ninyo & Moore during construction, we request that the selected consultant provide the client with a letter (with a copy to Ninyo & Moore) indicating that they fully understand Ninyo & Moore’s recommendations, and that they are in full agreement with the design parameters and recom- mendations contained in this report. Construction of proposed improvements should be performed by qualified contractors utilizing appropriate techniques and construction materials. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 19 10. LIMITATIONS The field evaluation, laboratory testing, and geotechnical analyses presented in this geotechnical report have been conducted in general accordance with current practice and the standard of care exercised by geotechnical consultants performing similar tasks in the project area. No warranty, expressed or implied, is made regarding the conclusions, recommendations, and opinions pre- sented in this report. There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and conditions not observed or described in this report may be encountered during construction. Uncertainties relative to subsurface conditions can be reduced through addi- tional subsurface exploration. Additional subsurface evaluation will be performed upon request. Please also note that our evaluation was limited to assessment of the geotechnical aspects of the project, and did not include evaluation of structural issues. This document is intended to be used only in its entirety. No portion of the document, by itself, is de- signed to completely represent any aspect of the project described herein. Ninyo & Moore should be contacted if the reader requires additional information or has questions regarding the content, interpre- tations presented, or completeness of this document. This report is intended for design purposes only. It does not provide sufficient data to prepare an accurate bid by contractors. It is suggested that the bidders and their geotechnical consultant per- form an independent evaluation of the subsurface conditions in the project areas. The independent evaluations may include, but not be limited to, review of other geotechnical reports prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory testing. Our conclusions, recommendations, and opinions are based on an analysis of the observed site conditions. If geotechnical conditions different from those described in this report are encountered, our office should be notified and additional recommendations, if warranted, will be provided upon request. It should be understood that the conditions of a site could change with time as a result of natural processes or the activities of man at the subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to government ac- tion or the broadening of knowledge. The findings of this report may, therefore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore has no control. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 20 This report is intended exclusively for use by the client. Any use or reuse of the findings, conclu- sions, and/or recommendations of this report by parties other than the client is undertaken at said parties’ sole risk. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 21 11. REFERENCES American Concrete Institute (ACI), 2010, ACI 318 Building Code Requirements for Structural Concrete and Commentary. American Society of Civil Engineers (ASCE), 2010, Minimum Design Loads for Buildings and Other Structures, ASCE 7-10. Anderson, J.G., Rockwell, T.K., and Agnew, D.C., 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region: Earthquake Engineering Research Institute (EERI), Earthquake Spectra, Volume 5, No. 2. Benton Engineering, Inc., 1977, Soils Investigation for Proposed Commercial Development, Southeasterly Area of La Costa Avenue and El Camino Real Intersection, Carlsbad, Cali- fornia: dated December 14. Brian Smith Engineers, Inc., 1982, As-Built Grading Plans for Plaza de la Costa Real: dated February 24. Building News, 2012, “Greenbook,” Standard Specifications for Public Works Construction: BNI Publications. California Building Standards Commission, 2013, California Building Code, Title 24, Part 2, Volumes 1 and 2. California Department of Transportation (Caltrans), 2012, Corrosion Guidelines (Version 2.0), Divi- sion of Engineering and Testing Services, Corrosion Technology Branch: dated November. California Geological Survey, 2008b (revised), Earthquake Shaking Potential for California: Map Sheet 48. California Geological Survey (CGS), 1975, Character and Recency of Faulting, San Diego Met- ropolitan Area, California, Special Report 123. California Geological Survey, 2013, California Historical Earthquake Online Database, http://redirect.conservation.ca.gov/cgs/rghm/quakes/historical/index.htm. Cao, T., Bryant, W. A., Rowshandel, B., Branum, D., and Willis, C. J., 2003, The Revised 2002 California Probabilistic Seismic Hazards Maps: California Geological Survey: dated June. City of Carlsbad, 2004, City of Carlsbad Engineering Standards, Volume 3, Standard Drawings and Specifications. Geotracker, 2015, http://geotracker.swrcb.ca.gov/: accessed in March. Google, Inc., 2015, http://www.googleearth.com: accessed in March. Harden, D.R., 1998, California Geology: Prentice Hall, Inc. La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc 22 Hartley, J.D., and Duncan, J.M., 1987, E′ and Its Variation with Depth: American Society of Civil Engineers (ASCE), Journal of Transportation Engineering, Vol. 113, No. 5: dated September. Jennings, C.W., 2010, Fault Activity Map of California and Adjacent Areas: California Geologi- cal Survey, California Geologic Data Map Series, Map No. 6, Scale 1:750,000 Kennedy, M.P., Tan, S.S, Bovard, K.R., Alvarez, R.M., Watson, M.J., and Gutierrez, C.I., 2007, Geologic Map of the Oceanside 30’ X 60’ Quadrangle, California: California Geological Survey, Regional Geologic Map No. 2, Scale 1:100,000. Mour Group, 2015, Plans for La Costa Repositioning: dated January 30 Ninyo & Moore, In-house proprietary information. Norris, R.M., and Webb, R.W., 1990, Geology of California, Second Edition: John Wiley & Sons, Inc. Tan, 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California, Landslide Hazard Identification Map No. 33, Open-File Report 95-03, Scale 1:24,000. Treiman, J. A., 1993, The Rose Canyon Fault Zone Southern California: California Geological Survey Open-File Report 93-02. United States Department of the Interior, Bureau of Reclamation, 1989, Engineering Geology Field Manual. United States Department of the Interior, 2014, Circular Area Earthquake Search website http://earthquake.usgs.gov/earthquakes/eqarchives/epic/epic_circ.php.: accessed April. United States Geological Survey, 2008, National Seismic Hazard Maps - Fault Parameters, World Wide Web, http://geohazards.usgs.gov/cfusion/hazfaults_search/. United States Geological Survey, 2012, Encinitas Quadrangle, California-San Diego County, 7.5-Minute Series (Topographic): Scale 1:24,000. United States Geological Survey (USGS), 2013, U.S. Seismic Design Maps website, http://geohazards.usgs.gov/designmaps/us/application.php. AERIAL PHOTOGRAPHS Source Date Flight Numbers Scale USDA March 30, 1953 AXN-2M 68 and 69 1:24,000 SOURCE: 2008 THOMAS GUIDE FOR SAN DIEGO COUNTY, STREET GUIDE AND DIRECTORY; MAP © RAND MCNALLY, R.L.07-S-129 NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 1_107302005_SL.mxd AOB"SITE §¨¦8 §¨¦5 §¨¦15 §¨¦805 §¨¦215 MAP INDEX San DiegoCounty 0 2,400 4,8001,200 SCALE IN FEET LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA SITE LOCATION FIGURE 1PROJECT NO.DATE 107302005 4/15 ± ± NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE LEGEND PROJECT AREA " 7710 EL CAMINO REALRENOVATION UNDERSEPARATE REPORT 0 300 600150 SCALE IN FEET PROJECT AREA FIGURE 2PROJECT NO.DATE 2_107089005_PA.mxd AOB107302005 4/15 LA COSTA AVENUE EL CAM INO R EA L SOURCE: Aerial Imagery - Photo Date: Feb 11, 2010, ESRI, i-cubed, USDA FSA, USGS, AEX, GeoEye, Getmapping, Aerogrid, IGP. LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA E L CAM INO REA L @A B-3 TD=30.8'@AB-1 TD=30.5' @A B-2 TD=20.3' @?HA-2 TD=3.5' @?HA-1 TD=4.0' HA-3 TD=3.5'@? LA COSTA AVENUE ± NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 0 250 500125 SCALE IN FEET BORING LOCATIONS FIGURE 3PROJECT NO.DATE 3_107089005_BL.mxd AOB107302005 4/15 SOURCE: Aerial Imagery - Photo Date: Feb 11, 2010, ESRI, i-cubed, USDA FSA, USGS, AEX,GeoEye, Getmapping, Aerogrid, IGP. LEGEND PROJECT AREA @A B-3 TD=30.8' BORING TD=TOTAL DEPTH IN FEET @?HA-3 TD=3.5' HAND AUGER BORING TD=TOTAL DEPTH IN FEET LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA " 7710 EL CAMINO REALRENOVATION UNDERSEPARATE REPORT NOTES: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE SCALE IN FEET GEOLOGY FIGURE 4PROJECT NO.DATE ± SITE SOURCE: KENNEDY, M.P., AND TAN, S.S., 2005, GEOLOGIC MAP OF THE OCEANSIDE 30' X 60' QUADRANGLE, CALIFORNIA 107302005 4/154_107302005_G.mxd AOBMETASEDIMENTARY AND METAVOLCANIC ROCKS UNDIVIDED U D FAULT - SOLID WHERE ACCURATELYLOCATED, DASHED WHERE APPROXIMATE, DOTTED WHERE CONCEALED. ARROW AND NUMBER INDICATE DIRECTION AND ANGLE OF DIP OF FAULT PLANE LEGEND 65 PARALIC ESTUARINE DEPOSITSQpe MZu SANTIAGO FORMATIONTsa YOUNG ALLUVIAL FLOODPLAIN DEPOSITS" "" "" " " "" " """" "" Qya VERY OLD PARALIC DEPOSITS, UNIT 10Qvop11 VERY OLD PARALIC DEPOSITS, UNIT 10Qvop10 TORREY SANDSTONETt DELMAR FORMATIONTd Qvop11 Qvop10 Tsa Td Qya MZu Qoa OLD ALLUVIAL FLOODPLAIN DEPOSITSQoa 0 2,000 4,000 LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA !!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! M E X I C OUSAP a c i f i c O c e a n SAN JACINTO ELSINORE IM P E RIA L WHITTIER SAN ANDREAS NEW PORT-INGLEWOOD C O R O N A D O B A N K S A N DIE G O T R O U G H SAN CLEMENTE S A N T A C RUZ-SANTA CATALINA RIDGE P A L O S VERDES OF F S H O R E Z O N E OF D E F O R M A T I O NGARLOCKWHITE WOLFCLEARWATERS A N GABRIEL SIERRA MADRE BANNING MISSION CREEK BLA C K W A TE RHARPER LOCKHART LEN W O O D CAMP ROCK CALIC O LUDLOW PIS GAHBULLION M O U N T AIN JO HN S O N VALLEY EM ERSO N P IN T O M O UNTAINMANIX MIRAGE VALLEY NORTHHELENDALE FRONTAL CHINO S A N J O S ECUCAMON G A MALIBU COAS T SA N T A MONICA SANCAYETANO SANTASUSANASIMI-S A N T A R O S A N O R T H R ID G E C HA RN O C K S A W P ITCAN Y O N SUPERSTITION HILLS NEVADA CALIFORNIA R O S E C A N YONSan Bernardino County Kern County Riverside CountySan Diego County Imperial County Los Angeles County V e n t u r a C o u n t y Or a n g e C o u n t y Riverside CountySan Bernardino CountyL o s A n g e l e s C o u n t y Kern CountyIndioIrvine Pomona Mojave Anaheim Barstow Temecula Palmdale El CentroSanDiego Escondido Oceanside SantaAna Riverside Tehachapi Long Beach Wrightwood ChulaVista Los Angeles Victorville SanClemente PalmSprings Big Bear CityThousandOaksSanBernardino LakeArrowhead Twentynine Palms Baker DesertCenter ! ! CALIFORNIA 0 30 60 SCALE IN MILES LEGEND HOLOCENE ACTIVE CALIFORNIA FAULT ACTIVITY HISTORICALLY ACTIVE LATE QUATERNARY (POTENTIALLY ACTIVE) STATE/COUNTY BOUNDARY QUATERNARY (POTENTIALLY ACTIVE)"SITE ! SOURCE: JENNINGS, C.W., AND BRYANT, W.A., 2010, FAULT ACTIVITY MAP OF CALIFORNIA, CALIFORNIA GEOLOGICAL SURVEY.5_107302005_F.mxd AOBNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. FAULT LOCATIONS FIGURE 5PROJECT NO.DATE ± 107302005 4/15 LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA aPpP D PASSIVE PRESSURE ACTIVE PRESSURE LATERAL EARTH PRESSURES FOR YIELDING RETAINING WALLS H/3 RESULTANT D/3 NOTES: ASSUMES NO HYDROSTATIC PRESSURE BUILD-UP BEHIND THE RETAINING WALL 1. 2. BEHIND THE RETAINING WALL WALL DRAINAGE DETAIL SHOULD BE INSTALLED DRAINS AS RECOMMENDED IN THE RETAINING3. 5. RECOMMENDED GEOTECHNICAL DESIGN PARAMETERS Equivalent Fluid Pressure (lb/ft /ft) Lateral Earth Pressure Level Backfillwith Granular Soils 2 (1) (2)with Granular Soils2H:1V Sloping Backfill(2) aP pP 300 D 140 D 40 H 65 H Level Ground 2H:1V Descending Ground H AND D ARE IN FEET (H IS LESS THAN 12 FEET) 6.SETBACK SHOULD BE IN ACCORDANCE WITH THE CBC (2013) H RESULTANT 4/15 DATE 107302005 PROJECT NO.6 FIGURE RETAINING WALL 4.SURCHARGE PRESSURES CAUSED BY VEHICLES OR NEARBY STRUCTURES ARE NOT INCLUDED 6 107302005 d-yrw.dwgGRANULAR BACKFILL MATERIALS SHOULD BE USED FOR RETAINING WALL BACKFILL LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA oPpP D PASSIVE PRESSURE AT-REST PRESSURE LATERAL EARTH PRESSURES FOR RESTRAINED RETAINING WALLS H/3 RESULTANT D/3 NOTES: ASSUMES NO HYDROSTATIC PRESSURE BUILD-UP BEHIND THE RETAINING WALL 1. 2. BEHIND THE RETAINING WALL WALL DRAINAGE DETAIL SHOULD BE INSTALLED DRAINS AS RECOMMENDED IN THE RETAINING3. RECOMMENDED GEOTECHNICAL DESIGN PARAMETERS Equivalent Fluid Pressure (lb/ft /ft) Lateral Earth Pressure Level Backfillwith Granular Soils 2 (1) (2)with Granular Soils2H:1V Sloping Backfill(2) OP pP 300 D 140 D 65 H 95 H Level Ground 2H:1V Descending Ground H AND D ARE IN FEET5. SLAB RESULTANT FIGURE 7PROJECT NO.DATE RETAINING WALL OR NEARBY STRUCTURES ARE NOT INCLUDED SURCHARGE PRESSURES CAUSED BY VEHICLES4.7 107302005 d-rrw.dwg4/15 LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA107302005 GRANULAR BACKFILL MATERIALS SHOULD BE USED FOR RETAINING WALL BACKFILL RETAINING WALL DRAINAGE DETAIL SOIL BACKFILL COMPACTED TO 90% RELATIVE COMPACTION * OUTLET 4-INCH-DIAMETER PERFORATED SCHEDULE 40 PVC PIPE OR EQUIVALENT INSTALLED WITH PERFORATIONS DOWN; 1% GRADIENT OR MORE TO A SUITABLE 3/4-INCH OPEN-GRADED GRAVEL WRAPPED IN AN APPROVED GEOFABRIC. 3 INCHES WALL FOOTING FINISHED GRADE RETAINING WALL 12 INCHES 12 INCHES VARIESDATEPROJECT NO.8 FIGURE NOTE: AS AN ALTERNATIVE, AN APPROVED GEOCOMPOSITE DRAIN SYSTEM MAY BE USED. GEOFABRIC *BASED ON ASTM D1557 8 107302005 d-rw.dwg4/15107302005 LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LA COSTA AVENUE CARLSBAD, CALIFORNIA La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc APPENDIX A BORING LOGS Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using bulk samples. Bulk Samples of represen- tative earth materials were obtained from the exploratory borings. The samples were bagged and transported to the laboratory for testing. Field Procedure for the Collection of Relatively Undisturbed Samples Relatively undisturbed soil samples were obtained in the field using the Modified Split-Barrel Drive Sampler. The sampler, with an external diameter of 3.0 inches, was lined with 1-inch long, thin brass rings with inside diameters of approximately 2.4 inches. The sample barrel was driven into the ground with the weight of a 140-pound hammer, in general accordance with ASTM D 3550-01. The driving weight was permitted to fall freely. The approximate length of the fall, the weight of the hammer, and the number of blows per foot of driving are presented on the boring logs as an index to the relative resistance of the materials sampled. The samples were removed from the sample barrel in the brass rings, sealed, and transported to the laboratory for testing. 0 5 10 15 20 XX/XX SM CL Bulk sample. Modified split-barrel drive sampler. 2-inch inner diameter split-barrel drive sampler. No recovery with modified split-barrel drive sampler, or 2-inch inner diameter split-barrel drive sampler. Sample retained by others. Standard Penetration Test (SPT). No recovery with a SPT. Shelby tube sample. Distance pushed in inches/length of sample recovered in inches. No recovery with Shelby tube sampler. Continuous Push Sample. Seepage. Groundwater encountered during drilling. Groundwater measured after drilling. MAJOR MATERIAL TYPE (SOIL):Solid line denotes unit change. Dashed line denotes material change. Attitudes: Strike/Dip b: Bedding c: Contact j: Joint f: Fracture F: Fault cs: Clay Seam s: Shear bss: Basal Slide Surface sf: Shear Fracture sz: Shear Zone sbs: Shear Bedding Surface The total depth line is a solid line that is drawn at the bottom of the boring. BORING LOG Explanation of Boring Log Symbols PROJECT NO. DATE FIGUREDEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.BORING LOG EXPLANATION SHEET SOIL CLASSIFICATION CHART PER ASTM D 2488 PRIMARY DIVISIONS SECONDARY DIVISIONS GROUP SYMBOL GROUP NAME COARSE- GRAINED SOILS more than 50% retained on No. 200 sieve GRAVEL more than 50% of coarse fraction retained on No. 4 sieve CLEAN GRAVELless than 5% fines GW well-graded GRAVEL GP poorly graded GRAVEL GRAVEL with DUAL CLASSIFICATIONS 5% to 12% fines GW-GM well-graded GRAVEL with silt GP-GM poorly graded GRAVEL with silt GW-GC well-graded GRAVEL with clay GP-GC poorly graded GRAVEL with clay GRAVEL with FINES more than 12% fines GM silty GRAVEL GC clayey GRAVEL GC-GM silty, clayey GRAVEL SAND 50% or more of coarse fraction passes No. 4 sieve CLEAN SAND less than 5% fines SW well-graded SAND SP poorly graded SAND SAND with DUAL CLASSIFICATIONS 5% to 12% fines SW-SM well-graded SAND with silt SP-SM poorly graded SAND with silt SW-SC well-graded SAND with clay SP-SC poorly graded SAND with clay SAND with FINES more than 12% fines SM silty SAND SC clayey SAND SC-SM silty, clayey SAND FINE- GRAINED SOILS 50% or more passes No. 200 sieve SILT and CLAY liquid limit less than 50% INORGANIC CL lean CLAY ML SILT CL-ML silty CLAY ORGANIC OL (PI > 4)organic CLAY OL (PI < 4)organic SILT SILT and CLAY liquid limit 50% or more INORGANIC CH fat CLAY MH elastic SILT ORGANIC OH (plots on or above “A”-line)organic CLAY OH (plots below “A”-line)organic SILT Highly Organic Soils PT Peat USCS METHOD OF SOIL CLASSIFICATION Explanation of USCS Method of Soil Classification PROJECT NO.DATE FIGURE APPARENT DENSITY - COARSE-GRAINED SOIL APPARENT DENSITY SPOOLING CABLE OR CATHEAD AUTOMATIC TRIP HAMMER SPT (blows/foot) MODIFIED SPLIT BARREL (blows/foot) SPT (blows/foot) MODIFIED SPLIT BARREL (blows/foot) Very Loose < 4 < 8 < 3 < 5 Loose 5 - 10 9 - 21 4 - 7 6 - 14 Medium Dense 11 - 30 22 - 63 8 - 20 15 - 42 Dense 31 - 50 64 - 105 21 - 33 43 - 70 Very Dense > 50 > 105 > 33 > 70 CONSISTENCY - FINE-GRAINED SOIL CONSIS-TENCY SPOOLING CABLE OR CATHEAD AUTOMATIC TRIP HAMMER SPT (blows/foot) MODIFIED SPLIT BARREL (blows/foot) SPT (blows/foot) MODIFIED SPLIT BARREL (blows/foot) Very Soft < 2 < 3 < 1 < 2 Soft 2 - 4 3 - 5 1 - 3 2 - 3 Firm 5 - 8 6 - 10 4 - 5 4 - 6 Stiff 9 - 15 11 - 20 6 - 10 7 - 13 Very Stiff 16 - 30 21 - 39 11 - 20 14 - 26 Hard > 30 > 39 > 20 > 26 LIQUID LIMIT (LL), %PLASTICITY INDEX (PI), %0 10 107 4 20 30 40 50 60 70 0 20 30 40 50 60 70 80 90 100 MH or OH ML or OLCL - ML PLASTICITY CHART GRAIN SIZE DESCRIPTION SIEVE SIZE GRAIN SIZE APPROXIMATE SIZE Boulders > 12”> 12”Larger than basketball-sized Cobbles 3 - 12”3 - 12”Fist-sized to basketball-sized Gravel Coarse 3/4 - 3”3/4 - 3”Thumb-sized to fist-sized Fine #4 - 3/4”0.19 - 0.75”Pea-sized to thumb-sized Sand Coarse #10 - #4 0.079 - 0.19”Rock-salt-sized to pea-sized Medium #40 - #10 0.017 - 0.079”Sugar-sized to rock-salt-sized Fine #200 - #40 0.0029 - 0.017” Flour-sized to sugar-sized Fines Passing #200 < 0.0029”Flour-sized and smaller CH or OH CL or OL 0 10 20 30 40 SM SC ASPHALT CONCRETE:Approximately 4 inches thick. FILL:Reddish brown, moist, medium dense, silty fine to coarse SAND; micaceous.Mottled grayish olive and reddish brown, moist, medium dense, clayey fine SAND. Total Depth = 4.0 feet. Groundwater not encountered. Backfilled and patched shortly after drilling on 3/16/15. Note: Groundwater, though not encountered at the time of drilling, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report. The ground elevation shown above is an estimation only. It is based on our interpretations of published maps and other documents reviewed for the purposes of this evaluation. It is not sufficiently accurate for preparing construction bids and design documents. BORING LOG LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LACOSTA AVENUE, CARLSBAD, CALIFORNIA PROJECT NO. 107302005 DATE 4/15 FIGURE A-1DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION DATE DRILLED 3/16/15 BORING NO.HA-1 GROUND ELEVATION 64'  (MSL)SHEET 1 OF METHOD OF DRILLING Manual DRIVE WEIGHT N/A DROP N/A SAMPLED BY AQP LOGGED BY AQP REVIEWED BY RDH 1 0 10 20 30 40 SM SC ASPHALT CONCRETE:Approximately 2.5 inches thick. FILL:Reddish brown, moist, medium dense, silty fine to coarse SAND; micaceous.Mottled reddish brown and olive, moist, medium dense, clayey fine SAND.Total Depth = 3.5 feet. Groundwater not encountered. Backfilled and patched shortly after drilling on 3/16/15. Note: Groundwater, though not encountered at the time of drilling, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report. The ground elevation shown above is an estimation only. It is based on our interpretations of published maps and other documents reviewed for the purposes of this evaluation. It is not sufficiently accurate for preparing construction bids and design documents. BORING LOG LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LACOSTA AVENUE, CARLSBAD, CALIFORNIA PROJECT NO. 107302005 DATE 4/15 FIGURE A-2DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION DATE DRILLED 3/16/15 BORING NO.HA-2 GROUND ELEVATION 63'  (MSL)SHEET 1 OF METHOD OF DRILLING Manual DRIVE WEIGHT N/A DROP N/A SAMPLED BY AQP LOGGED BY AQP REVIEWED BY RDH 1 0 10 20 30 40 SM SC ASPHALT CONCRETE:Approximately 4.8 inches thick. FILL:Reddish brown, moist, medium dense, silty fine to coarse SAND; micaceous.Mottled light reddish brown and grayish olive, moist, medium dense, clayey fine SAND.Total Depth = 3.5 feet. Groundwater not encountered. Backfilled and patched shortly after drilling on 3/16/15. Note: Groundwater, though not encountered at the time of drilling, may rise to a higher level due to seasonal variations in precipitation and several other factors as discussed in the report. The ground elevation shown above is an estimation only. It is based on our interpretations of published maps and other documents reviewed for the purposes of this evaluation. It is not sufficiently accurate for preparing construction bids and design documents. BORING LOG LA COSTA TOWNE CENTER TENANT IMPROVEMENTS EL CAMINO REAL AND LACOSTA AVENUE, CARLSBAD, CALIFORNIA PROJECT NO. 107302005 DATE 4/15 FIGURE A-3DEPTH (feet)BulkSAMPLESDrivenBLOWS/FOOTMOISTURE (%)DRY DENSITY (PCF)SYMBOLCLASSIFICATIONU.S.C.S.DESCRIPTION/INTERPRETATION DATE DRILLED 3/16/15 BORING NO.HA-3 GROUND ELEVATION 63'  (MSL)SHEET 1 OF METHOD OF DRILLING Manual DRIVE WEIGHT N/A DROP N/A SAMPLED BY AQP LOGGED BY AQP REVIEWED BY RDH 1 La Costa Towne Center Tenant Improvements April 17, 2015 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302005 107302005 R Improvements.doc APPENDIX B LABORATORY TESTING Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D 2488. Soil classifications are indicated on the logs of the exploratory borings in Appendix A. Atterberg Limits Tests were performed on a selected representative fine-grained soil sample to evaluate the liquid limit, plastic limit, and plasticity index in general accordance with ASTM D 4318. These test re- sults were utilized to evaluate the soil classification in accordance with USCS. The test results and classifications are shown on Figure B-1. R-Value The resistance value, or R-value, for site soils was evaluated in general accordance with Califor- nia Test (CT) 301. Samples were prepared and evaluated for exudation pressure and expansion pressure. The equilibrium R-value is reported as the lesser or more conservative of the two cal- culated results. The test results are shown on Figure B-2. August 9, 2012 Project No. 107302002 Mr. Geoffrey Sherman Excel Trust, Inc. 17140 Bernardo Center Drive, Suite 300 San Diego, California 92128 Subject: Addendum to Geotechnical Report Building 7760 Addition at the La Costa Towne Center El Camino Real and La Costa Avenue Carlsbad, California References: California Building Standards Commission (CBSC), 2010, California Building Code (CBC). Ninyo & Moore, 2012, Geotechnical Evaluation, La Costa Towne Center, El Camino Real and La Costa Avenue, Carlsbad: dated July 13. Dear Mr. Sherman: In accordance with your request, we have prepared this addendum to the referenced geotechnical report. The recommendations presented in this document are considered applicable to the pro- posed additions to the building located at 7760 El Camino Real in Carlsbad, California. These recommendations are not intended to supersede the recommendations in the referenced report (Ninyo & Moore, 2012), but are intended to supplement them. The following recommendations for Building 7760 are based on our geologic reconnaissance of the site performed on July 27, 2012 and our review of the referenced report (Ninyo & Moore, 2012). Based on information provided by the client and our site reconnaissance, the existing building consists of a single-story, wood-frame structure founded on shallow foundations with a concrete slab-on-grade floor system. The structure was previously utilized as a bank facility and has an asphalt concrete (AC) pavement drive-through lane that wraps around the north, west and south sides of the building. Retaining masonry walls up to approximately 8 feet with sloping backfill support the drive-through lane on the north and west sides of the building. Building 7760 Addition at the La Costa Towne Center August 9, 2012 El Camino Real and La Costa Avenue, Carlsbad, California Project No. 107302002 107302002 L Addendum.doc 2 From discussions with the client and our review of schematic plans, we understand that Build- ing 7760 will be remodeled. As part of the remodeling efforts, the drive-through lane along the north, west, and south sides of the existing building will be demolished to allow construction of new improvements. These proposed improvements include a building addition to the west side of the building, a concrete patio with a screen wall along the north side of the building, and various hardscape and landscaping improvements on the north, west, and south sides of the building. After removal of existing improvements (including the drive-through lane) and underground utilities within the proposed areas of improvement around Building 7760, we recommend that the upper 2 feet of the exposed subgrade soils be overexcavated, moisture conditioned to near optimum moisture content, and recompacted to a relative compaction of 90 percent as evaluated by the ASTM International D 1557. The overexcavation should extend a horizontal distance of 2 feet beyond the proposed limits of the improvement areas, where feasible. Based on our site reconnaissance, if shallow foundations are used for the proposed western building addition, a surcharge load will be imposed on the adjacent retaining wall. To mitigate this situation, we recommend that the western building addition be supported on a foundation system consisting of concrete, cast-in-drilled-hole (CIDH) foundations. The CIDH foundations may be designed using an allowable bearing capacity of 1,500 pounds per square foot (psf) in accordance with Table 1806.2 of the California Building Code (CBC) for a clay soil. The CIDH foundations should consist of a grade beam system to support the concrete slab for the western building addition. It is recommended that the proposed slab-on-grade reinforcement be doweled to the exterior foundations of the existing structure. For the design of the screen wall at the patio area, we recommend that the wall be supported on a continuous footing. The continuous footing should have an embedment depth of 24 inches and a width of 15 inches or more. Based on these dimensions, the continuous footing may be designed using an allowable bearing capacity of 1,500 psf in accordance with Table 1806.2 of the CBC for a clay soil. 5710 Ruffin Road | San Diego, California 92123 | p. 858.576.1000 | www.ninyoandmoore.com September 13, 2021 Project No. 108375001 Mr. Will Dukes Asana Partners 11752 San Vicente Boulevard Los Angeles, California 90049 Subject: Response to Third-Party Review and Plan Review The Beacon La Costa – Phase 3 7760 and 7770 El Camino Real Carlsbad, California Dear Mr. Dukes: In accordance with your request, we have reviewed the refer referenced project plans (AO Architects, 2021a and 2021b) for conformance with our updated geotechnical evaluation (Ninyo & Moore, 2021). Based on our review of the project plans, we note the following: Buildings D and E Plans, Sheet S1.1: our report (Ninyo & Moore, 2021) should be referenced. Buildings D and E Plans, Sheet S1.1, Structural Design Criteria Note 3: per 2019 California Building Code (CBC) and American Society of Civil Engineers (ASCE) 7-16 publication, a site specific acceleration response spectra was run and the SDS and SD1 should be = 0.765 and 0.500, respectively. Buildings D and E Plans, Sheet S1.1, Cast-in-Place Concrete Note 5: site soils correspond to site exposure classification S2, therefore concrete with a compressive strength of 4,500 pounds per square inch (psi) should be used for concrete in contact with soil. Based on our review, the project structural plans generally conform to the recommendations and findings presented in the updated geotechnical evaluation report (Ninyo & Moore, 2021), with the exceptions and revisions noted above. We appreciate the opportunity to provide services on this project. Respectfully submitted, NINYO & MOORE Christine M. Kuhns, PE Project Engineer Christina Tretinjak, PG, CEGSenior Project Geologist Ronald S. Halbert, PE Principal Engineer CMK/CAT/RSH/gg Attachment: References Ninyo & Moore | 7760 and 7770 El Camino Real, Carlsbad, California | 108375002 | September 13, 2021 REFERENCES American Society of Civil Engineers (ASCE), 2017, Minimum Design Loads for Buildings and Other Structures, ASCE 7-16. AO Architects, 2021a, Plans for The Beacon La Costa – Phase 3, Building D, Carlsbad, CA 92009: dated July 16. AO Architects, 2021b, Plans for The Beacon La Costa – Phase 3, Building E, Carlsbad, CA 92009: dated July 16. California Building Standards Commission, 2019, California Building Code (CBC): California Code of Regulations, Title 24, Part 2, Volumes 1 and 2, based on the 2018 International Building Code. Hetherington Engineering Inc., 2021, Third-Party Geotechnical Review (First), Proposed Improvements, 7760 & 7770 El Camino Real, Carlsbad, California, Project ID: CD 2020-0022/GR 2021-0024: dated July 14. Ninyo & Moore, 2012, Geotechnical Consulting Services, Former Vons Grocery Store, Carlsbad, California, Project No. 107302004: dated September 14. Ninyo & Moore, 2015a, Geotechnical Evaluation, La Costa Towne Centre Proposed Equinox Fitness Center, 7710 El Camino Real, Carlsbad, California, Project No. 107302005: dated April 17. Ninyo & Moore, 2015b, Geotechnical Evaluation, La Costa Towne Centre Tenant Improvements, El Camino Real and La Costa Avenue, Carlsbad, California, Project No. 107302005: dated April 17. Ninyo & Moore, 2017, Geotechnical Evaluation, The Beacon Project, 7720 to 7750 El Camino Real, Carlsbad, California, Project No. 108375001: dated September 1. Ninyo & Moore, 2021, Geotechnical Evaluation, The Beacon La Costa _Phase 3, 7760 and 7770 El Camino Real, Carlsbad, California, Project No. 108375002: dated September 3. 5710 Ruffin Road | San Diego, California 92123 | p. 858.576.1000 | www.ninyoandmoore.com September 13, 2021 Project No. 108375001 Mr. Will Dukes Asana Partners 11752 San Vicente Boulevard Los Angeles, California 90049 Subject: Response to Third-Party Review and Plan Review The Beacon La Costa – Phase 3 7760 and 7770 El Camino Real Carlsbad, California Dear Mr. Dukes: We have prepared this letter in response to the third-party review letter prepared by Hetherington (2021). Our responses to the third-party comments are presented below. Comment 1: Due to the age of the Geotechnical Evaluation, the Consultant should provide an updated geotechnical report, addressing the plans, and provide updated seismic design criteria, grading and foundation recommendations consistent with the 2019 California Building Code (CBC) and [American Society of Civil Engineers (ASCE) 7-16 Publication], as necessary. Response: We prepared an updated geotechnical report (Ninyo & Moore, 2021a) to update our recommendations per the 2019 CBC and ASCE 7-16. Comment 2: The Consultant should review the project grading and foundation plans, provide any additional geotechnical recommendations considered necessary, and conform that the plans have been prepared in accordance with the geotechnical recommendations. Response: We prepared a plan review letter (Ninyo & Moore, 2021b) . Comment 3: The Consultant should provide a description of proposed site grading and improvements. Response: A description of the proposed site grading and improvements are included in our updated geotechnical report (Ninyo & Moore, 2021a). Comment 4: The Consultant should provide a geotechnical map/plot plan utilizing the latest grading plan for the project to clearly show (at a minimum) a) existing site topography, b) proposed structures/improvements, c) proposed finished grades and d) locations of the subsurface exploration. Response: Figure 1 of this letter shows the existing site topography, proposed structures/improvements, proposed finished grades, and locations of our subsurface explorations. Ninyo & Moore | 7760 and 7770 El Camino Real, Carlsbad, California | 108375002 | September 13, 2021 Comment 5: The Consultant should provide a statement as to the impact of the proposed grading and construction on adjacent properties. Response: The proposed grading operations and improvements at 7760 and 7770 El Camino Real should not have any impacts to the adjacent properties. Respectfully submitted, NINYO & MOORE Christine M. Kuhns, PE Project Engineer Christina Tretinjak, PG, CEG Senior Project Geologist Ronald S. Halbert, PE Principal Engineer CMK/CAT/RSH/gg Attachments: References Figure 1 – Site Plan Ninyo & Moore | 7760 and 7770 El Camino Real, Carlsbad, California | 108375002 | September 13, 2021 REFERENCES American Society of Civil Engineers (ASCE), 2017, Minimum Design Loads for Buildings and Other Structures, ASCE 7-16. AO Architects, 2021a, Plans for The Beacon La Costa – Phase 3, Building D, Carlsbad, CA 92009: dated July 16. AO Architects, 2021b, Plans for The Beacon La Costa – Phase 3, Building E, Carlsbad, CA 92009: dated July 16. California Building Standards Commission, 2019, California Building Code (CBC): California Code of Regulations, Title 24, Part 2, Volumes 1 and 2, based on the 2018 International Building Code. Hetherington Engineering Inc., 2021, Third-Party Geotechnical Review (First), Proposed Improvements, 7760 & 7770 El Camino Real, Carlsbad, California, Project ID: CD 2020- 0022/GR 2021-0024: dated July 14. Ninyo & Moore, 2012, Geotechnical Consulting Services, Former Vons Grocery Store, Carlsbad, California, Project No. 107302004: dated September 14. Ninyo & Moore, 2015a, Geotechnical Evaluation, La Costa Towne Centre Proposed Equinox Fitness Center, 7710 El Camino Real, Carlsbad, California, Project No. 107302005: dated April 17. Ninyo & Moore, 2015b, Geotechnical Evaluation, La Costa Towne Centre Tenant Improvements, Camino Real and La Costa Avenue, Carlsbad, California, Project No. 107302005: dated April 17. Ninyo & Moore, 2017, Geotechnical Evaluation, The Beacon Project, 7720 to 7750 El Camino Real, Carlsbad, California, Project No. 108375001: dated September 1. Ninyo & Moore, 2021a, Geotechnical Evaluation, The Beacon La Costa - Phase 3, 7760 and 7770 El Camino Real, Carlsbad, California, Project No. 108375002: dated September 3. Ninyo & Moore, 2021b, Plan Review, The Beacon La Costa - Phase 3, 7760 and 7770 El Camino Real, Carlsbad, California, Project No. 108375002: dated September 7. @?@?@?@?!H!H @A@A @A HA-3TD=3.5'@@?7760 7770 C-6/IT-2TD=5.0 1_108375002_BL.mxd 9/10/2021 AOBBORING LOCATIONS FIGURE 1 !o 0 60 120 FEET 108375002 | 9/21 THE BEACON LA COSTA - PHASE 37760 AND 7770 EL CAMINO REAL, CARLSBAD, CALIFORNIA LEGEND SITE BOUNDARY NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. | SOURCE: GOOGLE EARTH, 2021 @ HA-3TD=3.5 HAND AUGER BORING(NINYO & MOORE, 2015)TD=TOTAL DEPTH IN FEET@?PREVIOUS BORING/INFILTRATION TEST (NINYO & MOORE, 2017)TD=TOTAL DEPTH IN FEET C-6/IT-2TD=5.0 EL CA MI N O RE AL