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Home My WebLink AboutPD 2019-0012; BLOCK (WARD) RESIDENCE; REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED WARD RESIDENCE; 2020-10-05 REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED WARD RESIDENCE 3291 HIGHLAND AVENUE CARLSBAD, CALIFORNIA PREPARED FOR BRETT WARD 7043 WHITEWATER STREET CARLSBAD, CA 92011 PREPARED BY CHRISTIAN WHEELER ENGINEERING 3980 HOME AVENUE SAN DIEGO, CALIFORNIA 92105 CHRISTIAN WHEELER E N G I N E E R I N G 3 9 8 0 H o m e A v e nu e S a n Di e g o , C A 9 2 1 05 6 1 9 -5 5 0- 1 7 00 F A X 61 9 - 55 0 - 17 0 1 October 5, 2020 Brett Ward CWE 2200524.01 7043 Whitewater Street Carlsbad, CA 92011] Subject: Report of Preliminary Geotechnical Investigation Proposed Ward Residence, 3291 Highland Drive, Carlsbad, California Dear Mr. Ward: In accordance with your request and our proposal dated September 25, 2020, we have completed a preliminary geotechnical investigation for the proposed residence and associated improvements to be constructed at the subject property. We are presenting herewith a report of our findings and recommendations. It is our opinion and judgment that no geotechnical conditions exist at or in the vicinity of the subject property that would preclude the construction of the subject project, provided the recommendations included in this report are implemented. If you have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, CHRISTIAN WHEELER ENGINEERING Daniel B. Adler, RCE #36037 Daniel J. Flowers, CEG #2686 DBA:djf ec: brettoward@gmail.com CHRISTIAN WHEELER E N G I N E E R I N G 3 9 8 0 H o m e A v e nu e S a n Di e g o , C A 9 2 1 05 6 1 9 -5 5 0- 1 7 00 F A X 61 9 - 55 0 - 17 0 1 CWE 2200524.01 Proposed Ward Residence 3291 Highland Drive Carlsbad, California TABLE OF CONTENTS Page Introduction and Project Description .............................................................................................................................. 1 Scope of Services ................................................................................................................................................................. 2 Findings ................................................................................................................................................................................. 2 Site Description ............................................................................................................................................................... 2 General Geology and Subsurface Conditions ............................................................................................................ 3 Geologic Setting and Soil Description ..................................................................................................................... 3 Artificial Fill ............................................................................................................................................................. 3 Topsoil ...................................................................................................................................................................... 3 Old Paralic Deposits ............................................................................................................................................... 3 Groundwater ................................................................................................................................................................ 3 Tectonic Setting ........................................................................................................................................................... 3 Geologic Hazards ............................................................................................................................................................ 4 General.......................................................................................................................................................................... 4 Slope Stability ............................................................................................................................................................... 4 Liquefaction .................................................................................................................................................................. 5 Flooding ........................................................................................................................................................................ 5 Tsunamis ...................................................................................................................................................................... 5 Seiches ........................................................................................................................................................................... 5 Other Potential Geologic Hazards ........................................................................................................................... 5 Conclusions .......................................................................................................................................................................... 5 Recommendations ............................................................................................................................................................... 6 Grading and Earthwork ................................................................................................................................................. 6 General .......................................................................................................................................................................... 6 Pregrade Meeting ........................................................................................................................................................ 7 Observation of Grading ............................................................................................................................................. 7 Clearing and Grubbing ............................................................................................................................................... 7 Site Preparation ........................................................................................................................................................... 7 Processing of Fill Areas .............................................................................................................................................. 7 Compaction and Method of Filling ........................................................................................................................... 7 Surface Drainage ......................................................................................................................................................... 8 Temporary Slopes ........................................................................................................................................................... 8 Temporary Shoring ......................................................................................................................................................... 9 General.......................................................................................................................................................................... 9 Foundations ..................................................................................................................................................................... 9 General.......................................................................................................................................................................... 9 Dimensions .................................................................................................................................................................. 9 Bearing Capacity ........................................................................................................................................................... 9 Footing Reinforcing ..................................................................................................................................................... 9 Lateral Load Resistance .............................................................................................................................................10 Property Line Foundations .......................................................................................................................................10 Footing Excavation Compaction .............................................................................................................................10 Foundation Excavation Observation .......................................................................................................................10 Settlement Characteristics ........................................................................................................................................10 Expansive Characteristics ..........................................................................................................................................10 Foundation Plan Review ...........................................................................................................................................11 Soluble Sulfates ..........................................................................................................................................................11 Seismic Design Factors ................................................................................................................................................11 On-Grade Slabs .............................................................................................................................................................12 General ........................................................................................................................................................................12 Interior Floor Slabs ....................................................................................................................................................12 CWE 2200524.01 Proposed Ward Residence 3291 Highland Drive Carlsbad, California Under-Slab Vapor Retarders ...................................................................................................................................12 Exterior Concrete Flatwork.....................................................................................................................................12 Earth Retaining Walls ...................................................................................................................................................13 Foundations ...............................................................................................................................................................13 Passive Pressure .........................................................................................................................................................13 Active Pressure ..........................................................................................................................................................13 Waterproofing and Wall Drainage Systems ............................................................................................................13 Backfill .........................................................................................................................................................................13 Pavements .......................................................................................................................................................................14 Concrete Pavements .................................................................................................................................................14 Permeable Pavers ......................................................................................................................................................14 Limitations ..........................................................................................................................................................................14 Review, Observation and Testing ...............................................................................................................................14 Uniformity of Conditions ............................................................................................................................................15 Change in Scope ............................................................................................................................................................15 Time Limitations ...........................................................................................................................................................15 Professional Standard ...................................................................................................................................................15 Client's Responsibility ...................................................................................................................................................16 Field Explorations .............................................................................................................................................................16 Laboratory Testing ............................................................................................................................................................16 ATTACHMENTS FIGURES Figure 1 Site Vicinity Map, Follows Page 1 PLATES Plate 1 Site Plan & Geotechnical Map Plate 2-3 Geologic Cross Sections Plate 4 Typical Retaining Wall Drain System Detail APPENDICES Appendix A Subsurface Exploration Logs Appendix B Laboratory Test Results Appendix C References Appendix D Recommended Grading Specifications-General Provisions PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED WARD RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA INTRODUCTION AND PROJECT DESCRIPTION This report presents the results of a preliminary geotechnical investigation performed for the proposed residential project to be constructed at 3291 Highland Drive, Carlsbad, California. The following Figure Number 1 presents a vicinity map showing the location of the property. We understand that the subject project will consist of the demolition of the existing improvements at the site and construction of a new single-family residence and an attached garage. The residence will be a one and two-story structure with a partially subterranean lower levels under its main section and a portion of the garage. The structure will be of masonry and wood-frame construction, supported by conventional shallow foundations, and will incorporate concrete slab-on-grade floor system. Retaining walls up to about 10 feet in height are anticipated for the proposed structure. Exterior improvements include a swimming pool and masonry retaining walls up to about 5 feet high. It is expected that grading required for the project will consist of cuts up to about 10 feet and fills of less than a few feet from existing grades. To aid us in the preparation of this report, we were provided with grading plans prepared by Omega Engineering Consultants, dated August 17, 2020, structural plans prepared by Mike Surprenant & Associates, dated May 18, 2020, and a set of architectural plans prepared by Friehauf Architects, dated July 7, 2020. A copy of the grading plan has been used as the base for our Site Plan and Geotechnical Map, and is included herein as Plate No. 1. We have also created geologic cross sections A-A’ and B-B’ to depict the proposed construction, topography, and subsurface conditions at the subject site. The geologic cross sections are included on Plate Nos. 2 and 3 of this report. This report has been prepared for the exclusive use of Brett Ward, and his design consultants, for specific application to the project described herein. Should the project be modified, the conclusions and recommendations presented in this report should be reviewed by Christian Wheeler Engineering for conformance with our recommendations and to determine whether any additional subsurface investigation, laboratory testing and/or recommendations are necessary. Our professional services have been performed, CHRISTIAN WHEELER E N G I N E E R I N G 3 9 8 0 H o m e A v e nu e S a n Di e g o , C A 9 2 1 05 6 1 9 -5 5 0- 1 7 00 F A X 61 9 - 55 0 - 17 0 1 PROPOSED WARD RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA DATE:OCTOBER 2020 BY: SRD JOB NO.: 2200524.01 FIGURE NO.: 1 CHRISTIAN WHEELER E N G I N E E R I N G SITE VICINITY 2SHQ6WUHHW0DSFRQWULEXWRUV PROJECT SITE ... ~ (:, t ~ Bueno Vista Logoo11 urJ.a..Driv:!2 '~' Laguna DIM> i,. \ ~/ 11, 't~ ,1o, .• ~,:,• Cl ~~ ~\~- \ "½ "<>; 'I'~ <ll.' ~~ \\ ~,. ~✓ ,-I-~ . CWE 2200524.01 October 5, 2020 Page No. 2 our findings obtained and our recommendations prepared in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties, expressed or implied. PROJECT SCOPE The scope of our investigation consisted of a recent surface reconnaissance of the site and a review of a previously prepared Report of Preliminary Geotechnical Investigation Proposed Block Residence for a project at the subject site that never occurred (CWE 2190330.02) dated July 19, 2019. Data from the previous report was incorporated into this report. The previous investigation included subsurface exploration, obtaining representative soil samples, laboratory testing, analysis of the field and laboratory data, and review of relevant geologic literature. Our scope of service did not include assessment of hazardous substance contamination, recommendations to prevent floor slab moisture intrusion or the formation of mold within the structures, evaluation or design of storm water infiltration facilities, or any other services not specifically described in the scope of services presented below. Although a test for the presence of soluble sulfates within the soils that may be in contact with reinforced concrete was performed as part of the scope of our services, it should be understood Christian Wheeler Engineering does not practice corrosion engineering. If such an analysis is considered necessary, we recommend that the client retain an engineering firm that specializes in this field to consult with them on this matter. The results of the test should only be used as a guideline to determine whether additional testing and analysis is necessary. FINDINGS SITE DESCRIPTION The subject site consists of a developed, irregular-shaped lot located at 3291 Highland Drive, Carlsbad, California. The site is identified as Accessors Parcel Number 205-051-11 and presently supports a one-story, single-family residence and other associated improvements. A detached garage previously existed to the northwest of the residence which has been demolished. The property is bounded on the east by Highland Drive and on the remaining sides by developed residential properties. According to the grading plan (Omega, 2020), the site slopes gently to the west with elevations ranging from approximately156 feet at the westerly property line to approximately 171 feet at the easterly property line. CWE 2200524.01 October 5, 2020 Page No. 3 GENERAL GEOLOGY AND SUBSURFACE CONDITIONS GEOLOGIC SETTING AND SOIL DESCRIPTION: The subject site is located within the Coastal Plains Physiographic Province of San Diego County. Based on the results of our subsurface explorations, and analysis of readily available, pertinent geologic literature, it was determined that the area of the site investigated site is generally underlain by topsoil and sedimentary deposits locally referred to as old paralic deposits. These materials are described below: ARTIFICIAL FILL (Qaf): A layer of artificial fill approximately 1-foot-thick was encountered in test pit P-6. The upper 4 inches of the fill material appeared to be imported DG associated with the existing driveway. Artificial fill may exist in areas of the site not investigated. These materials generally consisted of light gray and light brown, dry, loose, silty sand (SM). The artificial fill was judged to have a very low Expansion Index (EI<20). TOPSOIL: A relatively thin layer of topsoil was encountered underlying the artificial fill or at grade throughout the site, except in test pit P-1 north. As encountered in the test pits, the topsoil layer had a maximum thickness of about 1½ feet (test pit P-3). The topsoil may be thicker in areas of the site not investigated. These materials generally consisted of light grayish-brown and light brown, dry, very loose and loose, silty sand (SM). The topsoil was judged to have a very low Expansion Index (EI<20). OLD PARALIC DEPOSITS (Qop): Quaternary-age old paralic deposits were encountered underlying the surficial soils throughout the site. These materials generally consisted of light brown, orangish-brown reddish-brown and grayish-brown, dry and moist, loose to medium, silty sand (SM). The old paralic deposits were found to be loose to medium dense. The old paralic deposits were judged to have a very low Expansion Index (EI<20). GROUNDWATER: No groundwater or seepage was encountered in our subsurface explorations. However, it should be recognized that minor groundwater seepage problems might occur after construction and landscaping are completed, even at a site where none were present before construction. These are usually minor phenomena and are often the result of an alteration in drainage patterns and/or an increase in irrigation water. Based on the anticipated construction and the permeability of the on-site soils, it is our opinion that any seepage problems that may occur will be minor in extent. It is further our opinion that these problems can be most effectively corrected on an individual basis if and when they occur. TECTONIC SETTING: No faults are known to traverse the subject site. However, it should be noted that much of Southern California, including the San Diego County area, is characterized by a series of Quaternary-age CWE 2200524.01 October 5, 2020 Page No. 4 fault zones that consist of several individual, en echelon faults that generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as “active” according to the criteria of the California Division of Mines and Geology. Active fault zones are those that have shown conclusive evidence of faulting during the Holocene Epoch (the most recent 11,000 years). The Division of Mines and Geology used the term “potentially active” on Earthquake Fault Zone maps until 1988 to refer to all Quaternary-age (last 1.6 million years) faults for the purpose of evaluation for possible zonation in accordance with the Alquist-Priolo Earthquake Fault Zoning Act and identified all Quaternary-age faults as “potentially active” except for certain faults that were presumed to be inactive based on direct geologic evidence of inactivity during all of Holocene time or longer. Some faults considered to be “potentially active” would be considered to be “active” but lack specific criteria used by the State Geologist, such as sufficiently active and well-defined. Faults older than Quaternary-age are not specifically defined in Special Publication 42, Fault Rupture Hazard Zones in California, published by the California Division of Mines and Geology. However, it is generally accepted that faults showing no movement during the Quaternary period may be considered to be “inactive”. Regionally, guidelines of the City of San Diego indicate that since the beginning of the Pleistocene Epoch marks the boundary between “potentially active” and “inactive” faults, unfaulted Pleistocene-age deposits are accepted as evidence that a fault may be considered to be “inactive.” A review of available geologic maps indicates that the nearest active fault zone is the Newport-Inglewood- Rose Canyon Fault Zone (RCFZ), located approximately 3 miles to the west of the site. Other fault zones in the region that could possibly affect the site include the Coronado Bank fault zones to the south west, the San Diego Trough and San Clemente fault zones to the west, the Newport-Inglewood and Palos Verdes fault zones to the northwest, and the Elsinore, Earthquake Valley, San Jacinto, and San Andreas fault zones to the northeast. GEOLOGIC HAZARDS GENERAL: No geologic hazards of sufficient magnitude to preclude the continued residential use or redevelopment of the site are known to exist. In our professional opinion and to the best of our knowledge, the site should be suitable for continued residential use or future redevelopment, provided sound engineering, construction, and site maintenance procedures are followed should the site be redeveloped. SLOPE STABILITY: The Relative Landslide Susceptibility and Landslide Distribution Map of the Oceanside Quadrangle prepared by the California Division of Mines and Geology indicates that the site is situated within Relative Landslide Susceptibility Area 3-1. Area 3 is considered to be “generally susceptible” to slope failures; Subarea 3-1 identifies areas with slopes that are at or near their stability limits due to a combination of weak materials and steep slopes. Most slopes in Subarea 3-1 do not contain landslide CWE 2200524.01 October 5, 2020 Page No. 5 deposits but may be expected to fail, locally, when adversely modified. We have also reviewed the publication, “Recent Slope Failures, Ancient Landslides, and related Geology of the North-Central Coastal Area, San Diego County” by Weber, 1982. This publication does not indicate any slope instability at the subject site. Based on our findings and the relatively flat topography on and surrounding the subject site it is our opinion that the potential for slope instability or landsliding can be considered very low. Further, it is anticipated that the proposed construction will not increase the potential for slope instability on or immediately adjacent to the subject site. LIQUEFACTION: The near-surface soils encountered at the site are not considered susceptible to liquefaction due to such factors as soil density and the absence of shallow groundwater conditions. FLOODING: As delineated on the Flood Insurance Rate Map (FIRM), map number 06073C0762G prepared by the Federal Emergency Management Agency, the site is in Zone X which is considered to be an “area of minimal flood hazard.” Areas of minimal flood hazards are located outside of the boundaries of both the 100-year and 500-year flood zones. TSUNAMIS: Tsunamis are great sea waves produced by a submarine earthquake or volcanic eruption. Review of the referenced Tsunami Inundation Map of the Oceanside/San Luis Rey Quadrangle indicates that the site is outside of both the projected tsunami inundation line and tsunami inundation area (CalEMA, 2009). SEICHES: Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs. Due to the site’s location, it is considered to have a negligible risk potential for seiches. OTHER POTENTIAL GEOLOGIC HAZARDS: Other potential geologic hazards such as, volcanoes or seismic-induced settlement should be considered to be negligible or nonexistent. CONCLUSIONS It is our professional opinion and judgment that no geotechnical conditions exist at or the general vicinity of the subject property that would preclude the construction of the proposed residence and associated improvements provided the recommendations presented herein are followed. The main geotechnical conditions affecting the proposed project consist of potentially compressible artificial fill, topsoil, and old paralic deposits, cut/fill transitions under the proposed structures, and temporary cut slopes. These conditions are discussed hereinafter. CWE 2200524.01 October 5, 2020 Page No. 6 The site was found to be underlain by potentially compressible fill soils, topsoil, and old paralic deposits. These soils are considered unsuitable, in their present condition, for the support of settlement-sensitive improvements. In order to mitigate this condition, it is recommended that these materials be partially removed and replaced as compacted fill. In addition, special consideration, as described hereinafter, will be necessary in areas of the site where this operation is unfeasible. A cut/fill transition is anticipated beneath the proposed structures. This condition will require special grading consideration as described hereinafter. Cut-fill transitions may result in differential settlements detrimental to the propose structure. In order to mitigate this condition, special compaction and slab-on-grade consideration is recommended. Temporary cut slopes up to about 12 feet in depth (including footing excavation) are anticipated for the proposed lower level construction. Due to the characteristics of the old paralic deposits, flatter than usual temporary cut slopes will be recommended. This recommendation may necessitate temporary shoring for temporary cuts near property lines. A swimming pool is proposed to the west of the new residence. No specific details are available regarding the proposed pool; however, it is our understanding that this will be a conventional pool. Additional recommendations, as necessary, will be provided by our firm once the pool plans are available for review. The site is located in an area that is relatively free of geologic hazards that will have a significant effect on the proposed construction. The most likely geologic hazard that could affect the site is ground shaking due to seismic activity along one of the regional active faults. However, construction in accordance with the requirements of the most recent edition of the California Building Code and the local governmental agencies should provide a level of life-safety suitable for the type of development proposed. RECOMMENDATIONS GRADING AND EARTHWORK GENERAL: All grading should conform to the guidelines presented in the current edition of the California Building Code, the minimum requirements of the City of Carlsbad, and the recommended Grading Specifications and Special Provisions attached hereto, except where specifically superseded in the text of this report. CWE 2200524.01 October 5, 2020 Page No. 7 PREGRADE MEETING: It is recommended that a pregrade meeting including the grading contractor, the client, and a representative from Christian Wheeler Engineering be performed, to discuss the recommendations of this report and address any issues that may affect grading operations. OBSERVATION OF GRADING: Continuous observation by the Geotechnical Consultant is essential during the grading operation to confirm conditions anticipated by our investigation, to allow adjustments in design criteria to reflect actual field conditions exposed, and to determine that the grading proceeds in general accordance with the recommendations contained herein. CLEARING AND GRUBBING: Site preparation should begin with the removal of existing improvements slated for demolition. The resulting debris and any existing vegetation and other deleterious materials in areas to receive proposed improvements or new fill soils should be removed from the site. SITE PREPARATION: It is recommended that existing fill soils, topsoil and old paralic deposits underlying the proposed structures, new fills, and any proposed exterior settlement sensitive improvements be removed to a minimum depth 5 feet from existing or proposed grade, whichever is more. Lateral removals limits should extend at least 5 feet beyond the perimeter of the improvements or removal depth, whichever is more. No removals are recommended beyond property lines. All excavated areas should be approved by the geotechnical engineer or his representative prior to replacing any of the excavated soils. The excavated materials can be replaced as properly compacted fill in accordance with the recommendations presented in the “Compaction and Method of Filling” section of this report. However, the existing fill encountered in the test pits was found to contain abundant roots and may have to be thoroughly cleaned prior to placement as compacted fill. 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 should be scarified to a depth of about 12 inches, watered thoroughly, and compacted to at least 90 percent relative compaction. COMPACTION AND METHOD OF FILLING: In general, all structural fill placed at the site should be compacted to a relative compaction of at least 90 percent of its maximum laboratory dry density as determined by ASTM Laboratory Test D1557. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick, with each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by the Geotechnical Consultant. Fill material should be free of rocks or lumps of soil in excess of 3 inches in maximum dimension. CWE 2200524.01 October 5, 2020 Page No. 8 Utility trench backfill within 5 feet of the proposed structures and beneath all concrete flatwork or pavements should be compacted to a minimum of 90 percent of its maximum dry density. SURFACE DRAINAGE: The drainage around the proposed improvements should be designed to collect and direct surface water away from proposed improvements toward appropriate drainage facilities. Rain gutters with downspouts that discharge runoff away from the structures into controlled drainage devices are recommended. The ground around the proposed improvements should be graded so that surface water flows rapidly away from the improvements without ponding. In general, we recommend that the ground adjacent to structure slope away at a gradient of at least 5 percent for a minimum distance of 10 feet. If the minimum distance of 10 feet cannot be achieved, an alternative method of drainage runoff away from the building at the termination of the 5 percent slope will need to be used. Swales and impervious surfaces that are located within 10 feet of the building should have a minimum slope of 2 percent. It is essential that new and existing drainage patterns be coordinated to produce proper drainage. Pervious hardscape surfaces adjacent to structures should be similarly graded. Drainage patterns provided at the time of construction should be maintained throughout the life of the proposed improvements. Site irrigation should be limited to the minimum necessary to sustain landscape growth. Over watering should be avoided. Should excessive irrigation, impaired drainage, or unusually high rainfall occur, zones of wet or saturated soil may develop. TEMPORARY SLOPES Temporary excavation slopes will be required for the construction of the subject project. The contractor is solely responsible for designing and constructing stable, temporary excavations and will need to shore, slope, or bench the sides of trench excavations as required to maintain the stability of the excavation sides. The contractor’s “competent person”, as defined in the OSHA Construction Standards for Excavations, 29 CFR, Part 1926, should evaluate the soil exposed in the excavations as part of the contractor’s safety process. The excavations required for footing construction are considered as part of the temporary slopes. It is recommended that temporary cut slopes be excavated at a continuous 1½:1 (horizontal to vertical) inclination. Our firm should be contacted to observe all temporary cut slopes during grading to ascertain that no unforeseen adverse conditions exist. No surcharge loads such as foundation loads, or soil or equipment stockpiles, vehicles, etc. should be allowed within a distance from the top of temporary slopes equal to half the slope height. CWE 2200524.01 October 5, 2020 Page No. 9 TEMPORARY SHORING GENERAL: Shoring may be necessary for the proposed construction. It is anticipated that the shoring system will utilize soldier beams with wooden lagging. The following design parameters may be assumed to calculate earth pressures on shoring. Angle of friction 32° Apparent cohesion 150 pounds per square foot Soil unit weight 120 pounds per cubic foot (pcf) Active pressures can be applied to shoring that is capable of rotating 0.002 radians. At-rest pressures should be applied to a shoring system that is unyielding and not able to rotate. These values do not include surcharge loads. Construction surcharge loads should be evaluated on a case-by-case basis. Vertical and lateral movements of the temporary shoring are expected to be small assuming an adequate lateral support system. FOUNDATIONS GENERAL: Based on our findings and engineering judgment, the proposed structures and exterior miscellaneous improvements may be supported by new conventional shallow foundations. The following recommendations are considered the minimum based on soil conditions and are not intended to be lieu of structural considerations. All foundations should be designed by a qualified structural engineer. DIMENSIONS: Spread footings supporting the proposed structures should be embedded at least 18 inches below lowest adjacent finish pad grade. Spread footings supporting the proposed light exterior improvements should be embedded at least 12 inches below lowest adjacent finish pad grade. Continuous and isolated footings should have a minimum width of 12 inches and 24 inches, respectively. Retaining wall footings should be at least 24 inches wide. BEARING CAPACITY: Spread footings with a minimum depth and minimum width of 12 inches may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf). This value may be increased by 500 psf for each additional foot of embedment and 400 psf for each additional foot of width up to a maximum of 3,000 psf. These values may be increased by one-third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING REINFORCING: Reinforcement requirements for foundations should be provided by a structural designer. However, based on the expected soil conditions, we recommend that the minimum CWE 2200524.01 October 5, 2020 Page No. 10 reinforcing for continuous footings consist of at least 2 No. 5 bars positioned near the bottom of the footing and 2 No. 5 bars positioned near the top of the footing. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be 0.30. The passive resistance may be considered to be equal to an equivalent fluid weight of 300 pounds per cubic foot. These values are based on the assumption that the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one-third. PROPERTY LINE FOUNDATIONS: Property line footings should extend to a depth such that the footing is at least 24 inches deep and founded at least 6 inches into competent old paralic deposits, whichever is greater. These footings may be designed for an allowable soil bearing pressure of 1,500 pounds per square foot (psf). This value may be increased by one-third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING EXCAVATION COMPACTION: The bottoms of property line footings should be watered thoroughly and compacted to at least 95% relative compaction. Compaction should be confirmed by performing in-place density tests. FOUNDATION EXCAVATION OBSERVATION: All footing excavations should be observed by Christian Wheeler Engineering prior to placing of forms and reinforcing steel to determine whether the foundation recommendations presented herein are followed and that the foundation soils are as anticipated in the preparation of this report. All footing excavations should be excavated neat, level, and square. All loose or unsuitable material should be removed prior to the placement of concrete. SETTLEMENT CHARACTERISTICS: The anticipated total and differential settlement is expected to be less than about 1 inch and 1 inch over 40 feet, respectively, provided the recommendations presented in this report are followed. It should be recognized that minor cracks normally occur in concrete slabs and foundations due to concrete shrinkage during curing or redistribution of stresses, therefore some cracks should be anticipated. Such cracks are not necessarily an indication of excessive vertical movements. EXPANSIVE CHARACTERISTICS: The prevailing foundation soils are assumed to have a very low expansion potential (EI<20). The recommendations within this report reflect these conditions. CWE 2200524.01 October 5, 2020 Page No. 11 FOUNDATION PLAN REVIEW: The final foundation plan and accompanying details and notes should be submitted to this office for review. The intent of our review will be to verify that the plans used for construction reflect the minimum dimensioning and reinforcing criteria presented in this section and that no additional criteria are required due to changes in the foundation type or layout. It is not our intent to review structural plans, notes, details, or calculations to verify that the design engineer has correctly applied the geotechnical design values. It is the responsibility of the design engineer to properly design/specify the foundations and other structural elements based on the requirements of the structure and considering the information presented in this report. SOLUBLE SULFATES: The water-soluble sulfate content of a selected soil sample from the site was determined in accordance with California Test Method 417. The results of this test indicate that the soil sample had a soluble sulfate content of 0.005 percent. Soils with a soluble sulfate content of less than 0.1 percent are considered to be negligible. However, it should be recognized that the sulfate content of surficial soils may increase with time due to soluble sulfate in the irrigation water or fertilized use. SEISMIC DESIGN FACTORS The seismic design factors applicable to the subject site are provided below. The seismic design factors were determined in accordance with the 2019 California Building Code. The site coefficients and adjusted maximum considered earthquake spectral response acceleration parameters are presented in the following Table I. TABLE I: SEISMIC DESIGN FACTORS Site Coordinates: Latitude Longitude 32.163° -117.335° Site Class C Site Coefficient Fa 1.2 Site Coefficient Fv 1.5 Spectral Response Acceleration at Short Periods Ss 1.044 g Spectral Response Acceleration at 1 Second Period S1 0.379 g SMS=FaSs 1.253 g SM1=FvS1 0.569 g SDS=2/3*SMS 0.835 g SD1=2/3*SM1 0.379 g Probable ground shaking levels at the site could range from slight to moderate, depending on such factors as the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience the effects of at least one moderate to large earthquake during the life of the proposed improvements. CWE 2200524.01 October 5, 2020 Page No. 12 ON-GRADE CONCRETE SLABS GENERAL: It is our understanding that the floor systems of the proposed structures will consist of a concrete slab-on-grade. The following recommendations are considered the minimum slab requirements based on the soil conditions and are not intended in lieu of structural considerations. These recommendations assume that the site preparation recommendations contained in this report are implemented. INTERIOR FLOOR SLABS: The minimum slab thickness should be 5 inches (actual) and the slab should be reinforced with at least No. 4 bars spaced at 18 inches on center each way. Slab reinforcement should be supported on chairs such that the reinforcing bars are positioned at mid-height in the floor slab. The slab reinforcement should extend down into the perimeter footings at least 12 inches. New slabs located adjacent to existing footings or slabs should be doweled as recommended by the project structural designer. UNDER-SLAB VAPOR RETARDERS: Steps should be taken to minimize the transmission of moisture vapor from the subsoil through the interior slabs where it can potentially damage the interior floor coverings. Local industry standards typically include the placement of a vapor retarder, such as plastic, in a layer of coarse sand placed directly beneath the concrete slab. Two inches of sand are typically used above and below the plastic. The vapor retarder should be at least 15-mil Stegowrap® or similar material with sealed seams and should extend at least 12 inches down the sides of the interior and perimeter footings. The sand should have a sand equivalent of at least 30, and contain less than 10% passing the Number 100 sieve and less than 5% passing the Number 200 sieve. The membrane should be placed in accordance with the recommendation and consideration of ACI 302, “Guide for Concrete Floor and Slab Construction” and ASTM E1643, “Standards Practice for Installation of Water Vapor Retarder Used in Contact with Earth or Granular Fill Under Concrete Slabs.” It is the flooring contractor’s responsibility to place floor coverings in accordance with the flooring manufacturer specifications. EXTERIOR CONCRETE FLATWORK: Exterior concrete slabs on grade should have a minimum thickness of 4 inches and be reinforced with at least No. 3 bars placed at 18 inches on center each way (ocew). Driveway slabs should have a minimum thickness of 5 inches and be reinforced with at least No. 4 bars placed at 18 inches ocew. Driveway slabs abutting landscape areas should be provided with a thickened edge a least 12 inches deep and 6 inches wide. All slabs should be provided with weakened plane joints in accordance with the American Concrete Institute (ACI) guidelines. Special attention should be paid to the method of concrete curing to reduce the potential for excessive shrinkage cracking. It should be recognized that minor cracks occur normally in concrete slabs due to shrinkage. Some shrinkage cracks should be expected and are not necessarily an indication of excessive movement or structural distress. CWE 2200524.01 October 5, 2020 Page No. 13 EARTH RETAINING WALLS FOUNDATIONS: Foundations for any proposed retaining walls should be constructed in accordance with the foundation recommendations presented previously in this report. PASSIVE PRESSURE: The passive pressure for the anticipated foundation soils may be considered to be 300 pounds per square foot per foot of depth. The upper foot of embedment should be neglected when calculating passive pressures, unless the foundation abuts a hard surface such as a concrete slab. The passive pressure may be increased by one-third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be 0.30 for the resistance to lateral movement. When combining frictional and passive resistance, the friction should be reduced by one-third. ACTIVE PRESSURE: The active soil pressure for the design of “unrestrained” and “restrained” earth retaining structures with level backfill may be assumed to be equivalent to the pressure of a fluid weighing 37 and 57 pounds per cubic foot, respectively. These pressures do not consider any other surcharge. If any are anticipated, this office should be contacted for the necessary increase in soil pressure. These values are based on a drained backfill condition. Seismic lateral earth pressures may be assumed to equal an inverted triangle starting at the bottom of the wall with the maximum pressure equal to 9H pounds per square foot (where H = wall height in feet) occurring at the top of the wall. WATERPROOFING AND WALL DRAINAGE SYSTEMS: The need for waterproofing should be evaluated by others. If required, the project architect should provide (or coordinate) waterproofing details for the retaining walls. The design values presented above are based on a drained backfill condition and do not consider hydrostatic pressures. The retaining wall designer should provide a detail for a wall drainage system. Typical retaining wall drain system details are presented as Plate No. 4 of this report for informational purposes. Additionally, outlet points for the retaining wall drain system should be coordinated with the project civil engineer. BACKFILL: Retaining wall backfill soils should be compacted to at least 90 percent relative compaction. Expansive or clayey soils should not be used for backfill material. The wall should not be backfilled until the masonry has reached an adequate strength. CWE 2200524.01 October 5, 2020 Page No. 14 PAVEMENTS CONCRETE PAVEMENTS: Concrete pavement construction should comply with the requirements set forth in Sections 201-1.1.2 and 302-6 of the Standard Specifications for Public Works Construction. The concrete materials should be a Class 560-C-3250 mix. All slabs should be provided with weakened plane joints in accordance with the American Concrete Institute (ACI) guidelines. Special attention should be paid to the method of concrete curing to reduce the potential for excessive shrinkage cracking. It should be recognized that minor cracks occur normally in concrete slabs due to shrinkage. Some shrinkage cracks should be expected and are not necessarily an indication of excessive movement or structural distress. PERMEABLE PAVERS: Pavers should be installed per manufacture specifications. The suitability of the pavers to support traffic loads should be confirmed by others. Prior to placing the base material, the subgrade soils should be scarified to a depth of 12 inches, moisture-conditioned and compacted to at least 95 percent of its maximum dry density as determined in accordance to ASTM D 1557. Geogrid material such as Tensar TX130S or equivalent is recommended under the crushed rock portion of the paver section within the driveway areas and is optional under the pedestrian areas. The bedding, base, and subbase layers should also extend the full detailed thickness to the perimeter concrete curbs. We also recommend that concrete curbs be poured along the edge of the proposed pavers and that the curbs extend at least 24 inches into the subgrade soil or 12 inches below the bottom of the subgrade rock storage section, whichever is greater. LIMITATIONS REVIEW, OBSERVATION AND TESTING The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the geotechnical engineer and engineering geologist so that they may review and verify their compliance with this report and with the California Building Code. It is recommended that Christian Wheeler Engineering be retained to provide continuous soil engineering services during the earthwork operations. This is to verify compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. CWE 2200524.01 October 5, 2020 Page No. 15 UNIFORMITY OF CONDITIONS The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and/or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the geotechnical engineer so that he may make modifications if necessary. CHANGE IN SCOPE This office should be advised of any changes in the project scope or proposed site grading so that we may determine if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. TIME LIMITATIONS The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether they be due to natural processes or the work of man on this or adjacent properties. In addition, changes in the Standards-of-Practice and/or Government Codes may occur. Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and recommendations. PROFESSIONAL STANDARD In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our borings, surveys, and explorations are made, and that our data, interpretations, and recommendations be based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be CWE 2200524.01 October 5, 2020 Page No. 16 performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. CLIENT'S RESPONSIBILITY It is the responsibility of the Client, or his representatives, to ensure that the information and recommendations contained herein are brought to the attention of the structural engineer and architect for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to insure that the contractor and his subcontractors carry out such recommendations during construction. FIELD EXPLORATIONS Eight subsurface explorations were made on June 14, 2019 at the locations indicated on the Site Plan and Geotechnical Map included herewith as Plate No. 1. These explorations consisted of hand-dug tests pit. The fieldwork was conducted under the observation and direction of our engineering geology personnel. The explorations were carefully logged when made. The logs are presented in the attached Appendix A. The soils are described in accordance with the Unified Soils Classification System. In addition, a verbal textural description, the wet color, the apparent moisture, and the density or consistency is provided. The density of granular soils is given as very loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard. Relatively undisturbed chunk samples and bulk samples of the earth materials encountered were collected and transported to our laboratory for testing. LABORATORY TESTING Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of the tests performed and the subsequent results are presented in Appendix B. P-5P-4P-1P-6P-7P-8P-2P-3QopQopQopQopBB'AA'P-8QopTEST PIT LOCATIONSOLD PARALIC DEPOSITSGEOLOGIC CROSS SECTION*Note: Topsoils and Artificial Fills 1' Not MappedCWE LEGENDDATE: OCTOBER 2020BY: SD JOB NO.: 2200524.01 PLATE NO.: 1SITE PLAN AND GEOLOGIC MAPPROPOSED WARD RESIDENCE3291 HIGHLAND DRIVECARLSBAD, CALIFORNIACHRISTIAN WHEELERE N G I N E E R I N G0020'40'SCALE: 1" = 20'/POOi.. ruwc ElEVAHON=t61.85 ) / . /'~:' \ I I /\ \.... f i fCJ·i snMH ./ I ~ \lft:.:::J~t ro 11: tJ/063 ~/ ~ . (174.tJ.918i:) i r ~ i ~ ~ '-4 rt: ~ MMlEGJ\ ENGINEERING CONSULTANTS 4340 VIEWRIDGEAVE. SUITE B SAN DIEGO, C1 92123 PH:(858) 634-8620 FAX:(858)-634-8627 I fl I < rsH1fi1 CITY OF CARLSBAD I SH7EETS I ~ ENGINEERING DEPARTMENT GRADING PLANS FOR: BLOCK RESIDENCE GR2019-0031 3291 HIGHLAND DRIVE GRADING PLAN APPROVED: JASON S. GELDERT CITY ENGINEER EXPIRES 9 PROJECT NO. PD2019-0012 DATE DRAWING NO. 519-7A PL 190 Al T I .----Proposed Wall I I 170'" I ----150'" P-7 Projected South4~ --..1 i Existing Grade Qop -P-4 Projected North 10' ---1/ t -Proposed Pool Depth Unknown [-Existing Residence-I I-Proposed Residence -J 1 Pad = 161.25' I Topsoil + P-8 Projected North 24' ,__ h + t Projected South 18' ~ Proposed Grade PL I I A' I -190 I I -170 Qop I 150 I I I 60 80 100 L _____ ....1..,_ _____ '!:--------!.~------;:;;-----~----1~·----~·~------i;;;'o----u 130 I I 120 140 160 180 0 W ~ CWELEGEND Qaf Artificial Fill Qop Old Paralic Deposits GEOLOGIC CROSS SECTION A-A' DATE: PROPOSED WARD RESIDENCE 3291 HIGHLAND AVENUE CARLSBAD, CALIFORNIA OCTOBER 2020 JOB NO.: 0 I 2200524.01 BY: SD PLATE NO.: 2 20' 40' SCALE: 1" = 20' CHRISTIAN WHEELER ENGINEERING PL 180 BI I I Qaf-170--I I I I ~ Proposed Garage ~I I Pad -+168' 7 t t--t-=:": -------------~_---_--_---_--_ --- ---t 160 -P-6 Projected East 30' 150 -Existing Grade-Proposed Grade-CWELEGEND Qaf Artificial Fill Qop Old Paralic Deposits GEOLOGIC CROSS SECTION B-B' Existing Residence Proposed Residence Pad= 161.25' P-8 Projected West 15' _t-DATE: BY: PROPOSED WARD RESIDENCE 3291 HIGHLAND AVENUE CARLSBAD, CALIFORNIA OCTOBER 2020 JOB NO.: -►1 --0 2200524.01 SD PLATE NO.: 3 PL B' I -180 170 ---160 150 10' 20' SCALE: 1" = 10' CHRISTIAN WHEELER ENGINEERING 1 3 5 5 5 1 1 3 2 2 3 4 NOTES AND DETAILS 1 GENERAL NOTES: 1) THE NEED FOR WATERPROOFING SHOULD BE EVALUATED BY OTHERS. 2) WATERPROOFING TO BE DESIGNED BY OTHERS (CWE CAN PROVIDE A DESIGN IF REQUESTED). 3) EXTEND DRAIN TO SUITABLE DISCHARGE POINT PER CIVIL ENGINEER. 4) DO NOT CONNECT SURFACE DRAINS TO SUBDRAIN SYSTEM. 4 2 3 4 5 UNDERLAY SUBDRAIN WITH AND CUT FABRIC BACK FROM DRAINAGE PANELS AND WRAP FABRIC AROUND PIPE. COLLECTION DRAIN (TOTAL DRAIN OR EQUIVALENT) LOCATED AT BASE OF WALL DRAINAGE PANEL PER MANUFACTURER'S RECOMMENDATIONS. 4 3 6 4 4 4 4 4 4 7 4-INCH PERFORATED PVC PIPE ON TOP OF FOOTING, HOLES POSITIONED DOWNWARD (SDR 35, SCHEDULE 40, OR EQUIVALENT). 34 INCH OPEN-GRADED CRUSHED AGGREGATE. GEOFARBRIC WRAPPED COMPLETELY AROUND ROCK. PROPERLY COMPACTED BACKFILL SOIL. WALL DRAINAGE PANELS (MIRADRAIN OR EQUIVALENT) PLACED PER MANUFACTURER'S REC'S. DETAILS: 6 7 12" 12"12" 12" 12" MIN. 6" MIN. 6" MIN.6" MIN. 1 DETAIL 2 2 DETAIL DETAIL DETAIL PROPOSED WARD RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA DATE: OCTOBER 2020 BY: SRD JOB NO.: 2200524.01 PLATE NO.: 4 CANTILEVER RETAINING WALL DRAINAGE SYSTEMS CHRISTIAN WHEELER E N G I N E E R I N G □----- i~~~~ 4 . cl 4 • /•~' ,, ' ~/, ~~ cl cl ~ ~ ~---------~~ □----- 0 Q; 0 0 0 □----- ~~~~ 4 cl a « / ~ ~" /~ cl □----- 0 0 I, Appendix A Subsurface Explorations LOG OF TEST PIT P-1 (North) SamEle Ty(!e and LaboratO!)'. Test Legend Cal Modified California Sampler CK Chunk SPT Standard Penetration Test DR Drive Ring ST Shelby Tube Date Logged: 6l14ll9 Equipment: Hand tools MD Max Density DS Direct Shear Logged By: DJF Auger Type: NIA S04 Soluble Sulfates Con Consolidation SA Sieve Analysis EI Expansion Index Existing Elevation: 163.0 feet Drive Type: NIA HA Hydrometer R-Val Resistance Value SE Sand Equivalent Chi Soluble Chlorides Finish Elevation: 162.0 feet Depth to Water: NIA PI Plasticity Index Res pH & Resistivity CP Collapse Potential SD Sample Density ~ c., Z,z-z ~ ..-l i:'-l ~ ~ ~ z 9 0 0 0 i:l-. if!. 0 i:Q i:: ,2 ~ ~f ~~ ~ ~ 0 S:l ~ SUMMARY OF SUBSURFACE CONDITIONS ~ ~ ~~ i:: i:'-l :i <') i5 ~ :i:: <') (based on Unified Soil Classification System) I-<"' ..-l <')~ 0~ i:l-. <') i:'-l ~ i:l-. ~ < i:l-. 01-< i:l-. :i u z ..9 ~ -z ~ ..-l ::s i:Q <') i:'-l <') ~e ;:i Oo ~8£ :s ~ 0 i:'-l c., ;:i <') i:Q ::s u 0 0 SM Old Paralic Dg,osits (QO(!): Light brown, damp, loose to medium dense, very - -fine-to medium-grained, SIL IT SAND, porous, friable, moderately weathered to .. OcS--.. 2 feet . .... .. - -... : .. 1 --·., .. - -: . ,. 15-; -:., ... ,. - - ,:;_ : : ~: 2--.... .. Reddish-brown, moist . . . ~ . - -::. 2.5-- Test pit terminated at 2.5 feet. - -No groundwater or seepage encountered. 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- Notes: --- Symbol Legend PROPOSED BLOCK RESIDENCE y Groundwater Level During Drilling 3291 HIGHLAND DRIVE " '! Groundwater Level After Drilling CARLSBAD, CALIFORNIA '' Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * No Sample Recovery ENGINEEIUNG ** Non-Representative Blow Count BY: SRD APPENDIX: A-2 /rocks oresent) ~ i5 i:l.. ~ 0 0 - - 0.5-- - - 1-- - - 15--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5-- - - 5-- - - 5.5-- - - 6-- - - 6.5-- - - 7-- - - 7.5-- LOG OF TEST PIT P-1 (East) Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ ~ z 0 i:::: ~ ~ SM .... SM : .. ·., .. ,:;_ . : ~: . .... ••• • t 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA ± 164.5 feet Drive Type: NIA 162.0 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) 6" PCC Footing ToEsoil: Light grayish-brown, dry, loose, very tine-to medium-grained, SILTY SAND with rootlets. Old Paralic DeEosits (QoJ>): Light brown, dry, loose, very fine- medium-grained, SIL TY SAND, porous, highly weathered. Crushed rock and 6" clay pipe leach line @l 1.5 to 2.5 feet, abundant roots. Orangish-brown, moist, loose to medium dense . Test pit terminated at 4 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z,z-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: --- Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA SamEle Ty(!e and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ i:l.. if!. 0 ~ ~f ~~ ~ ~ ~~ :i <') .... <')~ 0~ i:l.. ~ < i:l.. Oi--~ -z ~ .... ::s i:Q <') ;:i Oo ~8£ :s ~ <') i:Q ::s u 0 Cal " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGINEEIUNG SRD APPENDIX: A-1 ~ i5 ~ ~ 0 0 - - OcS-- - - 1 -- - - 15--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- LOG OF TEST PIT P-8 Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ c., ~ ..-l z g 0 i:Q 0 S:l ~ i:::: ~ :i:: rJl ~ rJl :i u rJl ~ c., ;::J SM .. .. .... .. .. : .. ·., .. ,. ; SM ; ,. ,. ,:;_ : ' .. .... .. .. ::. .. ... ·' :·} : ... : ·., .. , . ... ' ,. ... ... .. ' ,. ··'• : ,:: 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA 170.0 feet Drive Type: NIA 171.5 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) Topsoil: Grayish-brown, dry, very loose, very fine-to medium-grained, SILTY SAND with trace gravels . Old Paralic Deposits (Qop): Light brown, damp, loose to m~dium dense, very fine-to medium-grained, SIL TY-SAND, porous, friable, highly weathered to 3.5 feet. Reddish-brown, moist . Test pit terminated at 5 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA Sample Type and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ ~ if!. 0 ~ ~f ~~ ~ ~ ~~ :l rJl ..-l <Jl~ 0~ ~ ~ <~ Oi--~ -z ~ ..-l ::s i:Q rJl ;::J Oo ~8£ :s ~ rJl i:Q ::s u 0 " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGINEEIUNG SRD APPENDIX: A-9 ~ i5 i:l.. ~ 0 0 - - OcS-- - - 1 -- - - 15--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- LOG OF TEST PIT P-2 Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ ~ z 0 i:::: ~ ~ SM .... : .. ·., .. ,:;_ . : ~: . .... ... : 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA ± 163.0 feet Drive Type: NIA 162.0 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) 2" PCC Slab Old Paralic DeEosits (QoJ>): Reddish-brown, moist, loose to medium dense, very fine-to medium-grained, SILr SAND, upper 12" slightly Jeathered. Test pit terminated at 3 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: --- Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA SamEle Ty(!e and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ i:l.. if!. 0 ~ ~f ~~ ~ ~ ~~ :i <') .... <')~ 0~ i:l.. ~ < i:l.. Oi--~ -z ~ .... ::s i:Q <') ;:i Oo ~8£ :s ~ <') i:Q ::s u 0 CK " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGINEEIUNG SRD APPENDIX: A-3 ~ i5 i:l.. ~ 0 0 - - OcS-- - - 1-- - - 15--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- LOG OF TEST PIT P-3 Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ ~ z 0 i:::: ~ ~ SM .... : .. ·., .. ,:;_ . SM : . : . .... •••• t ···: ··'•: 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA ± 163.0 feet Drive Type: NIA 162.0 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) TO(!SOil: Light brown to light grayish-brown, dry, very loose, very fine-to medium-grained, SIL TYJ5AND, porous with rootlets and animal burrows. Old Paralic DCJ>Osits (Qo(!): Light brown to orangish-brown, damp, loose to medium dense, very I fine-to medium-grained, SIL TY SAND, friable, porous, moderately weathered to 3.5 feet. Reddish-brown, moist, medium dense. Test pit terminated at 5 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA SamEle Ty(!e and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ i:l.. if!. 0 ~ ~f ~~ ~ ~ ~~ :i <') .... <')~ 0~ i:l.. ~ < i:l.. Oi--~ -z ~ .... ::s i:Q <') ;:i Oo ~8£ :s ~ <') i:Q ::s u 0 CK CK 4.4 101.7 CP CK 6.9 112.4 CP " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGI NEE IUNG SRD APPENDIX: A-4 ~ i5 ~ ~ 0 0 - - 0cS-- - - 1 -- - - 15--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- LOG OF TEST PIT P-4 Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ c., ~ ..-l z 9 0 i:Q 0 S:l ~ i:::: ~ :i:: rJl ~ rJl :i u rJl ~ c., ;::J SM .. .. .... .. .. : .. ·., .. ,. ; SM ; , . .. ,:;_ : ' .. .... .. .. ::. .. ... ·' :·} .. : ... : · .. .. , . ... ' .. ... ... .. ' ,. ··'• : ,:: 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA ± 163.5 feet Drive Type: NIA 162.0 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) Topsoil: Light grayish-brown, dry, loose, very ftne-to medium-grained, SILTY SAND, porous with rootlets and animal burrows . Old Paralic Deposits (Qop): Light brown to orangish-brown, damp, loose to medium dense, very fine-to medium-grained, SIL TY SAND, friable, porous, highly weathered to 3 feet. Reddish-brown, moist . Test pit terminated at 5 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA Sample Type and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ if!. 0 ~ ~f ~~ ~ ~~ ..-l <Jl~ 0~ ~ ~ <~ ~ -z ~ ..-l ::s ;::J Oo ~8£ rJl i:Q ::s u 0 Cal 6.3 114.0 - Cal 9.0 113.1 " ~ ~ :l rJl Oi--i:Q rJl :s ~ SA TMD I DS CP CP Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGINEEIUNG SRD APPENDIX: A-5 ~ i5 i:l.. ~ 0 0 - - OcS-- - - 1 -- - - 1.5--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- LOG OF TEST PIT P-5 Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ ~ z 0 i:::: ~ ~ SM .... : .. ·.,·• SM ,:;_ . : . : . .... •••• t ···: ··'•: 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA 161.0 feet Drive Type: NIA 160.5 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) TO(!SOil: Light grayish-brown, dry, ve,;y loose, ftne-to medium-grained, SILTY SAND with rootlets. J Old Paralic Dg,osits (QO(!): Light brown, damp, loose, very fine-to medium-grained, SIL TY SAND with rootlets, porous, friable, highly weathered to 3 feet. Reddish-brown, moist, loose to medium dense. Test pit terminated at 5 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA SamEle Ty(!e and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ i:l.. if!. 0 ~ ~f ~~ ~ ~ ~~ :i <') .... <')~ 0~ i:l.. ~ < i:l.. Oi--~ -z ~ .... ::s i:Q <') ;:i Oo ~8£ :s ~ <') i:Q ::s u 0 " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGI NEE IUNG SRD APPENDIX: A-6 0 -- OcS-- -- 1-- -- 15--- -- 2-- -- 2.5-- -- 3-- -- 3.5-- -- 4-- -- 4.5 -- -- 5-- -- 5.5-- -- 6-- -- 6.5 -- -- 7-- -- 7.5-- LOG OF TEST PIT P-6 Date Logged: Logged By: Existing Elevation: Finish Elevation: .... SW- SM : •· SM ·., .. '.·: . SM .... •••• t ···: ··'•: 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA 165.0 feet Drive Type: NIA 163.75 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) Artificial Fill (Qat): Light gray, dry, loose, very fine-to coarse-grained, well-graded SAfD with silt. (4" DG driveway). ----- Light brown, chry, loose, very fine-to medium-grainied, SIL TY SAND. TO(!SOil: Light brown to light grayish-brown, damp, loose, very fine-to medium-grainied, SIL TI SAND, porous with roo1s. Old Paralic DeEosits (QoJ>): Reddish-brown, moisu, loose to medium dense, very fine-to medium-grained, SIIJTY SAND, porous, friable, highly weathered to 4 feet. L Test pit terminated at 5 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:: ,2 ~ ~ t ; z ..9 ~e Notes: Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA SamEle Ty(!e and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density i:'-l -~ z ~ i:l-. if!. 0 ~ ~f ~~ ~ i:'-l ~~ :i <') .... <')~ 0~ i:l-. ~ < i:l-. Oi--~ -z ~ .... ::s i:Q <') ;:i Oo ~8£ :s ~ <') i:Q ::s u 0 Cal 4.6 112.4 SD Cal " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGINEEIUNG SRD APPENDIX: A-7 ~ i5 i:l.. ~ 0 0 - - OcS-- - - 1 -- - - 1.5--- - - 2-- - - 2.5-- - - 3-- - - 3.5-- - - 4-- - - 4.5 -- - - 5-- - - 5.5 -- - - 6-- - - 6.5 -- - - 7-- - - 7.5-- LOG OF TEST PIT P-7 Date Logged: Logged By: Existing Elevation: Finish Elevation: ~ ~ z 0 i:::: ~ ~ SM .... : .. ·., .. : SM ,:;_ . : ~: . .... •••• t ···: 6l14ll9 Equipment: Hand tools DJF Auger Type: NIA 159.0 feet Drive Type: NIA 160.5 feet Depth to Water: NIA SUMMARY OF SUBSURFACE CONDITIONS (based on Unified Soil Classification System) To(!SOil: Light grayish-brown, dry, very loose, very fine-to medium-grained, SIL TY SAND with [ootlets and animal burrows. Old Paralic De(!OSits (Qo)'): Light brown, damp, loose, very fine-to medium-grained, SILTY0SAND, friable, porous, highly weatheredfto3.5 feet. Reddish-brwon, moist, loose to medium dense. Test pit terminated at 4.5 feet. No groundwater or seepage encountered. Cal SPT ST MD S04 SA HA SE PI CP Z-.:;-0 0 i:::: ,2 ~ ~ t ; z ..9 ~e Notes: Symbol Legend Groundwater Level During Drilling PROPOSED BLOCK RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA SamEle Ty(!e and LaboratO!)'. Test Legend Modified California Sampler CK Chunk Standard Penetration Test DR Drive Ring Shelby Tube Max Density DS Direct Shear Soluble Sulfates Con Consolidation Sieve Analysis EI Expansion Index Hydrometer R-Val Resistance Value Sand Equivalent Chi Soluble Chlorides Plasticity Index Res pH & Resistivity Collapse Potential SD Sample Density ~ ~ ~ z ~ i:l.. if!. 0 ~ ~f ~~ ~ ~ ~~ :i <') .... <')~ 0~ i:l.. ~ < i:l.. Oi--~ -z ~ .... ::s i:Q <') ;:i Oo ~8£ :s ~ <') i:Q ::s u 0 " Groundwater Level After Drilling Apparent Seepage DATE: JULY 2019 JOB NO.: 2190330.02 CHRISTIAN WHEELER. * ** No Sample Recovery Non-Representative Blow Count /rocks oresent) BY: ENGI NEE IUNG SRD APPENDIX: A-8 Appendix B Laboratory Test Results PROPOSED WARD RESIDENCE 3291 HIGHLAND DRIVE, CARLSBAD LAB SUMMARY BY: DBA DATE: OCT 2020 REPORT NO.:2200524.01 FIGURE NO.: B-1 E n g i n e e r i n g CHRISTIAN WHEELER Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. Brief descriptions of the tests performed are presented below: a) CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System and are presented on the exploration logs in Appendix A. b) MOISTURE-DENSITY: MOISTURE-DENSITY: In-place moisture contents and dry densities were determined for selected soil samples in accordance with ATM D 2937. The results are summarized in the test pit logs presented in Appendix A. c) MAXIMUM DENSITY & OPTIMUM MOISTURE CONTENT: The maximum dry density and optimum moisture content of typical soils were determined in the laboratory in accordance with ASTM Standard Test D1557, Method A. d) DIRECT SHEAR: Direct shear tests were performed on selected samples of the on-site soils in accordance with ASTM D3080. e) GRAIN SIZE DISTRIBUTION: The grain size distribution of a selected sample was determined in accordance with ASTM C136 and/or ASTM D422. f) COLLAPSE POTENTIAL: Collapse potential tests were performed on selected undisturbed soil samples in accordance with ASTM D5333. g) SOLUBLE SULFATE CONTENT: The soluble sulfate content was determined for a representative sample in accordance with California Test Methods 417. :. I I I CWE 2200524.01 October 5, 2020 Appendix B-2 LABORATORY TEST RESULTS PROPOSED WARD RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT (ASTM D1557) Sample Location Test Pit P-4 @ 1.25’-3’ Sample Description Light Brown Silty Sand (SM) Maximum Density 133.0 pcf Optimum Moisture 7.0 % DIRECT SHEAR (ASTM D3080) Sample Location Test Pit P-4 @ 1.25’-3’ Sample Type Remolded to 90% Friction Angle Cohesion 32° 150 psf GRAIN SIZE DISTRIBUTION (ASTM D422) Sample Location Test Pit P-4 @ 1.25’-3’ Sieve Size Percent Passing #4 100 #8 100 #16 99 #30 94 #50 60 #100 32 #200 23 COLLAPSE POTENTIAL (ASTM D 5333) Sample Location Test Pit P-3 @ 2½’ Test Pit P-3 @ 4½’ Initial Moisture Content 4.4 % 6.9 % Initial Density 101.7 pcf 112.4 pcf Consolidation Before Water Added 3.7 % 4.4 % Consolidation After Water Added 8.9 % 6.6 % Final Moisture 13.2 % 12.7 % Sample Location Test Pit P-4 @ 3’ Test Pit P-4 @ 5’ Initial Moisture Content 6.3 % 9.0 % Initial Density 114.0 pcf 113.1 pcf Consolidation Before Water Added 2.9 % 4.8 % Consolidation After Water Added 5.9 % 6.4 % Final Moisture 11.9 % 13.5 % CWE 2200524.01 October 5, 2020 Plate No. B-3 LABORATORY TEST RESULTS (Continued) SOLUBLE SULFATES (CALIFORNIA TEST 417) Sample Location Test Pit P-4 @ 0’-1.25’ Soluble Sulfate 0.005 % (SO4) Appendix C References CWE 2200524.01 October 5, 2020 Appendix C-1 REFERENCES American Society of Civil Engineers, ASCE 7 Hazard Tool, https://asce7hazardtool.online California Emergency Management Agency – California Geological Society – University of Southern California, 2009, Tsunami Inundation Map for Emergency Planning, Oceanside Quadrangle, San Luis Rey Quadrangle, scale 1:24,000, dated June 1, 2009. Christian Wheeler Engineering, Report of Preliminary Geotechnical Investigation, Proposed Block Residence, 3291 Highland Drive, Carlsbad, California, dated July 19, 2019 (CWE 2190330.02) F. Harold Weber, 1982, Recent Slope Failures, Ancient Landslides, and related Geology of the North-Central Coastal Area, San Diego County, CA, DMG Open-File Report 82-12 Federal Emergency Management Agency, 2012, San Diego County, California and Incorporated Areas Flood Insurance Rate Map, Map Panel Number 06073C0762G Friehauf Architects, Architectural Plans, Ward Residence, 3291 Highland Drive, Carlsbad, California, dated July 17, 2020. Giffen, Tan, S.S., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California, California Division of Mines and Geology Open-File Report 95-04 Historic Aerials, NETR Online, historicaerials.com Jennings, C.W. and Bryant, W. A., 2010, Fault Activity Map, California Geological Survey, Geologic Data Map No. 6, http://www.quake.ca.gov/gmaps/FAM/faultactivitymap.html Kennedy, Michael P. and Tan, Siang S., 2007, Geologic Map of the Oceanside 30’x60’ Quadrangle, California, California Geologic Survey, Map No. 2 Mike Surprenant & Associates, Structural Plans, Ward Residence, 3291 Highland Drive, dated May 18, 2020 Omega Engineering, Grading Plans for Block Residence, 3291 Highland Drive, dated August 17, 2020 U.S. Geological Survey, Quaternary Faults in Google Earth, http://earthquake.usgs.gov/hazards/qfaults/google.php Appendix D Recommended Grading Specifications – General Provisions CWE 2200524.01 October 5, 2020 Appendix D, Page D-1 RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS PROPOSED WARD RESIDENCE 3291 HIGHLAND DRIVE CARLSBAD, CALIFORNIA GENERAL INTENT The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the accepted plans. The recommendations contained in the preliminary geotechnical investigation report and/or the attached Special Provisions are a part of the Recommended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for which they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written communication signed by the Geotechnical Engineer. OBSERVATION AND TESTING Christian Wheeler Engineering shall be retained as the Geotechnical Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his representative provide adequate observation so that he may provide his opinion as to whether or not the work was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical Engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer shall be contacted for further recommendations. If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc., construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this work. Tests used to determine the degree of compaction should be performed in accordance with the following American Society for Testing and Materials test methods: CWE 2200524.01 October 5, 2020 Appendix D, Page D-2 Maximum Density & Optimum Moisture Content - ASTM D1557 Density of Soil In-Place - ASTM D1556 or ASTM D6938 All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM testing procedures. PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of. All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6 inches, brought to the proper moisture content, compacted and tested for the specified minimum degree of compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground which is defined as natural soil which possesses an in-situ density of at least 90 percent of its maximum dry density. When the slope of the natural ground receiving fill exceeds 20 percent (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm competent formational soil. The lower bench shall be at least 10 feet wide or 1-1/2 times the equipment width, whichever is greater, and shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the Geotechnical Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedure should be backfilled with acceptable soil that is compacted to the requirements of the Geotechnical Engineer. This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Geotechnical Engineer so that he may determine if any special recommendation will be necessary. All water wells which will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3 CWE 2200524.01 October 5, 2020 Appendix D, Page D-3 feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the well and should be determined by the Geotechnical Engineer and/or a qualified Structural Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the Geotechnical Engineer before being brought to the site. PLACING AND COMPACTION OF FILL Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in compacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to economically compact the layer. Compaction equipment should either be specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minimum degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non-structural fills is discussed in the geotechnical report, when applicable. Field observation and compaction tests to estimate the degree of compaction of the fill will be taken by the Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the Geotechnical Engineer's discretion. When the compaction test indicates that a particular layer is at less than the required degree of compaction, the layer shall be reworked to the satisfaction of the Geotechnical Engineer and until the desired relative compaction has been obtained. Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by sheepsfoot roller shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of CWE 2200524.01 October 5, 2020 Appendix D, Page D-4 two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over-built and cut- back to finish contours after the slope has been constructed. Slope compaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative compaction of at least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions section of this specification. The compaction operation on the slopes shall be continued until the Geotechnical Engineer is of the opinion that the slopes will be surficially stable. Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to determine if the required compaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Geotechnical Engineer or his representative in the form of a daily field report. If the method of achieving the required slope compaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction is obtained, at no cost to the Owner or Geotechnical Engineer. CUT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Geotechnical Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of the controlling governmental agency. ENGINEERING OBSERVATION Field observation by the Geotechnical Engineer or his representative shall be made during the filling and compaction operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or the observation and testing shall release the Grading Contractor from his duty to compact all fill material to the specified degree of compaction. CWE 2200524.01 October 5, 2020 Appendix D, Page D-5 SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before acceptance of work. RECOMMENDED GRADING SPECIFICATIONS - SPECIAL PROVISIONS RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural ground, compacted fill, and compacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper six inches should be compacted to at least 95 percent relative compaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29-2. OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil over 6 inches in diameter. Oversized materials should not be placed in fill unless recommendations of placement of such material are provided by the Geotechnical Engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and recompacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required.