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Home My WebLink AboutCDP 2017-0024; Highland James Subdivision (Highland Drive Portion); Geotechnical Investigation; 2016-11-09 GEOTECHNICAL INVESTIGATION PROPOSED 5-UNIT RESIDENTIAL SUBDIVISION 3980 HIGHLAND DRIVE CARLSBAD, CALIFORNIA Prepared for: VECK INVESTMENT PROPERTIES, LLC MS. ELIZABETH TEMPLE 3276 HIGHLAND DRIVE CARLSBAD, CALIFORNIA 92008 Prepared by: CONSTRUCTION TESTING & ENGINEERING, INC. 1441 MONTIEL ROAD, SUITE 115 ESCONDIDO, CALIFORNIA 92026 CTE JOB NO.: 10-12998G November 9, 2016 Construction Testing & Engineering, Inc. Inspection I Testing I Geotechnical I Environmental & Construction Engineering I Civil Engineering I Surveying 1441 Montiel Road, Suite 115 I Escondido, CA92026 I Ph (760) 746-4955 I Fax (760) 746-9806 I www.cte-inc.net TABLE OF CONTENTS 1.0 INTRODUCTION AND SCOPE OF SERVICES ................................................................... 1 1.1 Introduction ................................................................................................................... 1 1.2 Scope of Services .......................................................................................................... 1 2.0 SITE DESCRIPTION ............................................................................................................... 2 3.0 FIELD INVESTIGATION AND LABORATORY TESTING ................................................ 2 3.1 Field Investigation ........................................................................................................ 2 3.2 Laboratory Testing ........................................................................................................ 3 3.3 Percolation Testing ....................................................................................................... 3 4.0 GEOLOGY ............................................................................................................................... 4 4.1 General Setting ............................................................................................................. 4 4.2 Geologic Conditions ..................................................................................................... 5 4.2.1 Quaternary Undocumented Fill (unmapped) ................................................. 5 4.2.2 Quaternary Old Paralic Deposits (Qop) ......................................................... 5 4.3 Groundwater Conditions ............................................................................................... 5 4.4 Geologic Hazards .......................................................................................................... 6 4.4.1 Surface Fault Rupture .................................................................................... 6 4.4.2 Local and Regional Faulting .......................................................................... 6 4.4.3 Liquefaction and Seismic Settlement Evaluation .......................................... 7 4.4.4 Tsunamis and Seiche Evaluation ................................................................... 8 4.4.5 Landsliding .................................................................................................... 8 4.4.6 Compressible and Expansive Soils ................................................................ 8 4.4.7 Corrosive Soils ............................................................................................... 9 5.0 CONCLUSIONS AND RECOMMENDATIONS ................................................................. 10 5.1 General ........................................................................................................................ 10 5.2 Site Preparation ........................................................................................................... 10 5.3 Site Excavation ........................................................................................................... 11 5.4 Fill Placement and Compaction .................................................................................. 11 5.5 Fill Materials ............................................................................................................... 12 5.6 Temporary Construction Slopes ................................................................................. 13 5.7 Foundations and Slab Recommendations ................................................................... 13 5.7.1 Foundations .................................................................................................. 14 5.7.2 Foundation Settlement ................................................................................. 15 5.7.3 Foundation Setback ...................................................................................... 15 5.7.4 Interior Concrete Slabs ................................................................................ 15 5.8 Seismic Design Criteria .............................................................................................. 16 5.9 Lateral Resistance and Earth Pressures ...................................................................... 17 5.10 Exterior Flatwork ...................................................................................................... 19 5.11 Pavements ................................................................................................................. 20 5.12 Drainage .................................................................................................................... 21 5.13 Slopes ........................................................................................................................ 22 5.14 Plan Review .............................................................................................................. 22 5.15 Construction Observation ......................................................................................... 22 6.0 LIMITATIONS OF INVESTIGATION ................................................................................. 23 FIGURES FIGURE 1 SITE LOCATION MAP FIGURE 2 GEOLOGIC/ EXPLORATION LOCATION MAP FIGURE 3 REGIONAL FAULT AND SEISMICITY MAP FIGURE 4 CONCEPTUAL RETAINING WALL DRAINAGE APPENDICES APPENDIX A REFERENCES APPENDIX B FIELD EXPLORATION METHODS LOGS APPENDIX C LABORATORY METHODS AND RESULTS APPENDIX D STANDARD GRADING SPECIFICATIONS APPENDIX E SITE INSPECTION REPORT BY SOIL TESTERS Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 1 1.0 INTRODUCTION AND SCOPE OF SERVICES 1.1 Introduction This report presents the results of the geotechnical investigation, performed by Construction Testing and Engineering, Inc. (CTE), and provides preliminary conclusions and recommendations for the proposed improvements at the subject site located in Carlsbad, California. This investigation was performed to supplement the previous field investigation performed by Soil Testers (2005) which is attached in Appendix E. Information from the test pit logs and laboratory data from the previous study is incorporated into this report, as applicable. This investigation was performed in general accordance with the terms of CTE proposal G-3702B, dated September 23, 2016. CTE understands the proposed site improvements are to consist of five residential structures with associated parking, utilities, landscaping, and other ancillary improvements. Preliminary recommendations for excavations, fill placement, and foundation design for the proposed improvements are presented in this report. Additionally, percolation test results are provided from previous testing. Reviewed references are provided in Appendix A. 1.2 Scope of Services The scope of services provided included:  Review of readily available geologic and geotechnical reports.  Coordination of utility mark-out and location.  Excavation of exploratory borings and soil sampling utilizing limited-access manually operated excavation equipment.  Laboratory testing of selected soil samples.  Description of site geology and evaluation of potential geologic hazards. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 2  Engineering and geologic analysis.  Preparation of this geotechnical investigation report. 2.0 SITE DESCRIPTION The project site is located at 3980 Highland Drive in Carlsbad, California (Figure 1). The site is bounded by Highland Drive to the southwest and James Drive to the northeast with residential structures to the northwest and southeast. The project area generally descends to the northeast with elevations ranging from approximately 168 feet msl (above mean sea level) in the southwestern portion of the site to approximately 132 feet msl to the eastern portion of the site. 3.0 FIELD INVESTIGATION AND LABORATORY TESTING 3.1 Field Investigation CTE performed the recent field investigation on October 11, 2016. The field work consisted of site reconnaissance, and excavation of six borings. Due to limited access conditions, the explorations were excavated utilizing a manually operated three-inch diameter auger that was advanced to a depth of approximately 7.0 feet below the ground surface (bgs). Bulk samples were collected from the cuttings. The soils were logged in the field by a CTE Geologist and were visually classified in general accordance with the Unified Soil Classification System. The field descriptions have been modified, where appropriate, to reflect laboratory test results. Boring logs, including descriptions of the soils encountered, are included in Appendix B. The approximate locations of the borings are presented on Figure 2. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 3 3.2 Laboratory Testing Laboratory tests were conducted on selected soil samples for classification purposes, and to evaluate physical properties and engineering characteristics. Laboratory tests included: Gradation and Chemical Characteristics. Test descriptions and laboratory test results for the selected soils are included in Appendix C. 3.3 Percolation Testing CTE previously performed three percolation tests in specified areas of the site in general accordance with the County of San Diego Department of Environmental Health (SD DEH) procedures. The percolation test holes were excavated with a manually operated hand-auger on March 3, 2016 to depths ranging from approximately 2.0 to 4.0 feet below existing grade. The percolation tests were performed in accordance with SD DEH Case I and III methods. The Case I method is performed when presoak water remains in the test hole overnight and Case III is performed when presoak water percolates through the test hole overnight. The approximate percolation test locations are presented on Figure 2. The percolation test results are presented in the table below. The infiltration rates are presented without a factor of safety applied. TABLE 3.3 Test Location Soil Type San Diego County Percolation Procedure Depth (ft) Percolation Rate (minutes/inch) Infiltration Rate (inches per hour) P-1 Qop Case III 2.0 21 0.5 P-2 Qop Case III 2.0 10 1.1 P-3 Qop Case I 7.0 480 0.02 Qop = Quaternary Old Paralic Deposits Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 4 The percolation test results were obtained in accordance with City and County standards and performed with the standard of care practiced by other professionals practicing in the area. However, percolation test results can significantly vary laterally and vertically due to slight changes in soil type, degree of weathering, secondary mineralization, and other physical and chemical variabilities. As such, the test results are considered to be an estimate of percolation and converted infiltration rates for design purposes. No guarantee is made based on the percolation testing related to the actual functionality or longevity of associated infiltration basins or other BMP devices designed from the presented infiltration rates. 4.0 GEOLOGY 4.1 General Setting Carlsbad is located within the Peninsular Ranges physiographic province that is characterized by northwest-trending mountain ranges, intervening valleys, and predominantly northwest trending regional faults. The greater San Diego Region can be further subdivided into the coastal plain area, a central mountain–valley area and the eastern mountain valley area. The project site is located within the coastal plain area that is characterized by Cretaceous, Tertiary, and Quaternary sedimentary deposits that onlap an eroded basement surface consisting of Jurassic and Cretaceous crystalline rocks. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 5 4.2 Geologic Conditions Based on the regional geologic map prepared by Kennedy and Tan (2007), the near surface geologic unit underlying the site consists of Quaternary Old Paralic Deposits, Unit 2-4. Based on the recent explorations, Undocumented Fill was observed overlying the Quaternary Old Paralic Deposits. Descriptions of the geologic and soil units encountered are presented below. 4.2.1 Quaternary Undocumented Fill (unmapped) Where observed, the Quaternary Undocumented Fill generally consists of loose to medium dense, reddish brown, fine grained silty to clayey sand. This unit was observed to a depth of less than one foot bgs during the investigation, however, localized deeper fills will likely be encountered during grading and construction. 4.2.2 Quaternary Old Paralic Deposits (Qop) Quaternary Old Paralic Deposits were found to be the underlying geologic unit at the site. Where observed, these materials generally consist of medium dense to dense, reddish brown to light reddish brown clayey to silty fine grained sandstone. 4.3 Groundwater Conditions While groundwater conditions may vary, especially following periods of sustained precipitation or irrigation, it is generally not anticipated to affect the proposed construction activities or completed improvements, if proper site drainage is designed, installed, and maintained as per the recommendations of the project civil engineer of record. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 6 4.4 Geologic Hazards Geologic hazards that were considered to have potential impacts to site development were evaluated based on field observations, literature review, and laboratory test results. It appears that the geologic hazards at the site are primarily limited to those caused by shaking from earthquake-generated ground motions. The following paragraphs discuss the geologic hazards considered and their potential risk to the site. 4.4.1 Surface Fault Rupture Based on the site reconnaissance and review of referenced literature, the site is not within a State of California-designated Alquist-Priolo Earthquake Fault Studies Zone or Local Special Studies Zone and no known active fault traces underlie, or project toward, the site. According to the California Division of Mines and Geology, a fault is active if it displays evidence of activity in the last 11,000 years (Hart and Bryant, revised 2007). Therefore, the potential for surface rupture from displacement or fault movement beneath the proposed improvements is considered to be low. 4.4.2 Local and Regional Faulting The California Geological Survey (CGS) and the United States Geological Survey (USGS) broadly group faults as “Class A” or “Class B” (Cao, 2003; Frankel et al., 2002). Class A faults are generally identified based upon relatively well-defined paleoseismic activity, and a fault-slip rate of more than 5 millimeters per year (mm/yr). In contrast, Class B faults have comparatively less defined paleoseismic activity and are considered to have a fault-slip rate Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 7 less than 5 mm/yr. The nearest known Class B fault is the Rose Canyon Fault, which is approximately 8.9 kilometers west of the site (Blake, T.F., 2000). The nearest known Class A fault is the Temecula segment of the Elsinore Fault, which is located approximately 38.4 kilometers east of the site. The site could be subjected to significant shaking in the event of a major earthquake on any of the faults noted above or other faults in the southern California or northern Baja California area. 4.4.3 Liquefaction and Seismic Settlement Evaluation Liquefaction occurs when saturated fine-grained sands or silts lose their physical strengths during earthquake-induced shaking and behave like a liquid. This is due to loss of point-to-point grain contact and transfer of normal stress to the pore water. Liquefaction potential varies with water level, soil type, material gradation, relative density, and probable intensity and duration of ground shaking. Seismic settlement can occur with or without liquefaction; it results from densification of loose soils. The site is underlain at shallow depths by dense Old Paralic Deposits. In addition, loose surficial soils within proposed improvement areas are to be overexcavated and compacted as engineered fill. Therefore, the potential for liquefaction or significant seismic settlement at the site is considered to be low. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 8 4.4.4 Tsunamis and Seiche Evaluation According to State of California Emergency Management Agency mapping, the site is not located within a tsunami inundation zone based on distance from the coastline and elevation above sea level. Damage resulting from oscillatory waves (seiches) is considered unlikely due to the absence of nearby confined bodies of water. 4.4.5 Landsliding According to mapping by Tan (1995), the site is considered to be “Generally Susceptible” to landsliding, however, no landslides are mapped in the site area. In addition, landslides or similar associated features were not observed during the recent field exploration. Based on the investigation findings, landsliding is not considered to be a significant geologic hazard at the site. 4.4.6 Compressible and Expansive Soils Undocumented Fill Soils are considered to be potentially compressible. Therefore, these soils should be overexcavated, processed, and placed as a properly compacted fill as recommended herein. Based on the field data, previous laboratory testing, and site observations, the underlying formational deposits are not considered to be subject to significant compressibility under the proposed loads. Based on observation and previous laboratory test results, soils at the site are generally anticipated to exhibit Very Low to Low expansion potential (Expansion Index of 50 or less). Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 9 Therefore, expansive soils are not anticipated to present significant adverse impacts to site development. Additional evaluation of near-surface soils should be performed based on field observations during grading activities. 4.4.7 Corrosive Soils Chemical testing was performed to evaluate the potential effects that site soils may have on concrete foundations and various types of buried metallic utilities. Soil environments detrimental to concrete generally have elevated levels of soluble sulfates and/or pH levels less than 5.5. According to American Concrete Institute (ACI) Table 318 4.3.1, specific guidelines have been provided for concrete where concentrations of soluble sulfate (SO4) in soil exceed 0.1 percent by weight. These guidelines include low water: cement ratios, increased compressive strength, and specific cement type requirements. Based on the results of the Sulfate and pH testing performed, onsite soils are anticipated to generally have a negligible corrosion potential to Portland cement concrete improvements. A minimum resistivity value less than approximately 5,000 ohm-cm, and/or soluble chloride levels in excess of 200 ppm generally indicate a corrosive environment to buried metallic utilities and untreated conduits. Based on the obtained resistivity value of 5,010 ohm-cm and soluble chloride level of 43.2 ppm, onsite soils are anticipated to have a moderate corrosion potential for buried uncoated/unprotected metallic conduits. Based on these Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 10 results, at a minimum, the use of buried plastic piping or conduits would appear logical and beneficial, where feasible. The results of the chemical tests performed are presented in the attached Appendix C. However, CTE does not practice corrosion engineering. Therefore, a corrosion engineer or other qualified consultant could be contacted if site specific corrosivity issues are of concern. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 General CTE concludes that the proposed improvements at the site are feasible from a geotechnical standpoint, provided the recommendations in this report are incorporated into the design and construction of the project. Recommendations for the proposed earthwork and improvements are included in the following sections and Appendix D. However, recommendations in the text of this report supersede those presented in Appendix D should variations exist. These recommendations should either be evaluated as appropriate and/or updated during or following rough grading at the site. 5.2 Site Preparation Prior to grading, the proposed improvement areas should be cleared of existing debris and deleterious materials. Vegetation and other materials not suitable for structural backfill should be properly disposed of off site. In areas to receive structures, existing undocumented fills and any loose or disturbed soils should be removed to the depth of competent native material. In order to provide relatively uniform conditions under proposed structures, overexcavation should extend to a Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 11 minimum depth of two feet below proposed foundations. Where feasible, overexcavation should extend laterally at least five feet beyond the limits of the proposed improvements, or a distance equal to the depth of the overexcavation, whichever is greater. Overexcavation in proposed pavement or flatwork areas should be conducted to a minimum depth of two feet below proposed grade or to competent underlying materials, whichever depth is shallower. A CTE representative should observe the exposed ground surface prior to placement of compacted fill to document and verify the competency of the encountered subgrade materials. After approval by this office, the exposed subgrades to receive fill should be scarified a minimum of nine inches, moisture conditioned, and properly compacted prior to fill placement. 5.3 Site Excavation Generally, excavation of site materials may be accomplished with heavy-duty construction equipment under normal conditions. However, the Old Paralic Deposits are locally very granular and could be sensitive to caving and/or erosion, and may not effectively remain standing vertical, even at shallow or minor heights. 5.4 Fill Placement and Compaction Granular fill and backfill should be compacted to a minimum relative compaction of 90 percent at a moisture content of at least two percent above optimum, as evaluated by ASTM D 1557. The optimum lift thickness for fill soil will depend on the type of compaction equipment used. Generally, backfill should be placed in uniform, horizontal lifts not exceeding eight inches in loose Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 12 thickness. Fill placement and compaction should be conducted in conformance with local ordinances. 5.5 Fill Materials Properly moisture-conditioned very low to low expansion potential soils derived from the on-site excavations are considered suitable for reuse on the site as compacted fill. If used, these materials should be screened of organics and materials generally greater than three inches in maximum dimension. Irreducible materials greater than three inches in maximum dimension should generally not be used in shallow fills (within three feet of proposed grades). In utility trenches, adequate bedding should surround pipes. Imported fill beneath structures, flatwork, and pavements should have an Expansion Index of 20 or less (ASTM D 4829). Imported fill soils for use in structural or slope areas should be evaluated by the geotechnical engineer before being imported to the site. Retaining wall backfill located within a 45-degree wedge extending up from the heel of the wall should consist of soil having an Expansion Index of 20 or less (ASTM D 4829) with less than 30 percent passing the No. 200 sieve. The upper 12 to 18 inches of wall backfill could consist of lower permeability soils, in order to reduce surface water infiltration behind walls. The project structural engineer and/or architect should detail proper wall backdrains, including gravel drain zones, fills, filter fabric, and perforated drain pipes. A conceptual wall backdrain detail, which may be suitable for use at the site, is provided as Figure 4. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 13 5.6 Temporary Construction Slopes The following recommended slopes should be relatively stable against deep-seated failure, but may experience localized sloughing. On-site soils are considered Type B and Type C soils with recommended slope ratios as set forth in Table 5.6. However, due to the at least locally granular and erodible nature of the onsite soils, maximum 1.5:1 temporary slopes are anticipated to be more reliable, and vertical excavations may not remain standing. TABLE 5.6 RECOMMENDED TEMPORARY SLOPE RATIOS SOIL TYPE SLOPE RATIO (Horizontal: vertical) MAXIMUM HEIGHT B (Old Paralic Deposits) 1:1 (OR FLATTER) 10 Feet C (Undocumented Fill) 1.5:1 (OR FLATTER) 10 Feet Actual field conditions and soil type designations must be verified by a "competent person" while excavations exist, according to Cal-OSHA regulations. In addition, the above sloping recommendations do not allow for surcharge loading at the top of slopes by vehicular traffic, equipment or materials. Appropriate surcharge setbacks must be maintained from the top of all unshored slopes. 5.7 Foundations and Slab Recommendations The following recommendations are for preliminary design purposes only. These recommendations should be reviewed after completion of earthwork to document that conditions exposed are as anticipated and that the recommended structure design parameters are appropriate. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 14 5.7.1 Foundations Following the preparatory grading recommended herein, continuous and isolated spread footings are anticipated to be suitable for use at this site. It is anticipated that the proposed footings will be founded entirely on at least 24 inches of properly compacted fill placed as recommended herein. Footings should not straddle cut-fill interfaces. If deeper footings are proposed, additional overexcavation and compaction may be recommended in order to provide a minimum of 24 inches of fill beneath all foundation elements. Foundation dimensions and reinforcement should be based on an allowable bearing value of 2,500 pounds per square foot for footings founded in suitable fill materials and embedded a minimum of 18 inches below the lowest adjacent rough subgrade elevation. Continuous footings should be at least 15 inches wide; isolated footings should be at least 24 inches in least dimension. The above bearing values may be increased by one third for short duration loading which includes the effects of wind or seismic forces. Minimum footing reinforcement for continuous footings should consist of four No. 4 reinforcing bars; two placed near the top and two placed near the bottom, or as per the project structural engineer. The structural engineer should design isolated footing reinforcement. Footing excavations should generally be maintained above optimum moisture content until concrete placement. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 15 5.7.2 Foundation Settlement The maximum total static settlement is expected to be on the order of one inch and the maximum differential static settlement is expected to be on the order of ½ inch over a distance of approximately 40 feet. Due to the absence of a shallow groundwater table and the dense to very dense nature of underlying materials, dynamic settlement is not expected to adversely affect the proposed improvements. 5.7.3 Foundation Setback Footings for structures should be designed such that the horizontal distance from the face of adjacent slopes to the outer edge of the footing is at least 10 feet. In addition, footings should bear beneath a 1:1 plane extended up from the nearest bottom edge of adjacent trenches and/or excavations. Deepening of affected footings may be a suitable means of attaining the prescribed setbacks. 5.7.4 Interior Concrete Slabs Lightly loaded concrete slabs should be a minimum of 4.5 inches. Minimum slab reinforcement should consist of #4 reinforcing bars placed on maximum 18-inch centers each way, at above mid-slab height, but with proper cover. Slabs subjected to heavier loads may require thicker slab sections and/or increased reinforcement. Subgrade materials should be maintained above optimum moisture content until slab underlayment or concrete are placed. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 16 In moisture-sensitive floor areas, a suitable vapor retarder of at least ten-mil thickness (with all laps or penetrations sealed or taped) overlying a four-inch layer of consolidated minimum ½-inch crushed aggregate gravel should be installed per the current building code. An optional maximum two-inch layer of similar aggregate material may be placed above the vapor retarder to further protect the membrane during steel and concrete placement, if desired. This recommended moisture protection is generally considered typical of the area. However, CTE is not an expert at preventing moisture penetration through slabs. If proposed floor areas or coverings are considered especially sensitive to moisture emissions, additional recommendations from a specialty consultant could be obtained. A qualified architect or other experienced professional should be contacted if moisture penetration is a more significant concern. 5.8 Seismic Design Criteria The seismic ground motion values listed in the table below were derived in accordance with the ASCE 7-10 Standard and 2013 CBC. This was accomplished by establishing the Site Class based on the soil properties at the site, and then calculating the site coefficients and parameters using the United States Geological Survey Seismic Design Maps application using the site coordinates of 33.1536 degrees latitude and -117.3289 degrees longitude. These values are intended for the design of structures to resist the effects of earthquake ground motions. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 17 TABLE 5.9 SEISMIC GROUND MOTION VALUES PARAMETER VALUE CBC REFERENCE (2013) Site Class D ASCE 7, Chapter 20 Mapped Spectral Response Acceleration Parameter, SS 1.128 Figure 1613.3.1 (1) Mapped Spectral Response Acceleration Parameter, S1 0.433 Figure 1613.3.1 (2) Seismic Coefficient, Fa 1.049 Table 1613.3.3 (1) Seismic Coefficient, Fv 1.567 Table 1613.3.3 (2) MCE Spectral Response Acceleration Parameter, SMS 1.183 Section 1613.3.3 MCE Spectral Response Acceleration Parameter, SM1 0.678 Section 1613.3.3 Design Spectral Response Acceleration, Parameter SDS 0.789 Section 1613.3.4 Design Spectral Response Acceleration, Parameter SD1 0.452 Section 1613.3.4 Peak Ground Acceleration PGAM 0.469 ASCE 7, Section 11.8.3 5.9 Lateral Resistance and Earth Pressures Lateral loads acting against structures may be resisted by friction between the footings and the supporting soil or passive pressure acting against structures. If frictional resistance is used, we recommend allowable coefficients of friction of 0.30 (total frictional resistance equals the coefficient of friction multiplied by the dead load) for concrete cast directly against compacted fill. A design passive resistance value of 250 pounds per square foot per foot of depth (with a maximum value of 1,250 pounds per square foot) may be used. The allowable lateral resistance can be taken as the sum of the frictional resistance and the passive resistance, provided the passive resistance does not exceed two-thirds of the total allowable resistance. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 18 Retaining walls up to approximately eight feet high and backfilled using granular soils (either select onsite or suitable import) may be designed using the equivalent fluid weights given in Table 5.9 below. Lateral pressures on cantilever retaining walls (yielding walls) over six feet high due to earthquake motions may be calculated based on work by Seed and Whitman (1970). The total lateral thrust against a properly drained and backfilled cantilever retaining wall above the groundwater level can be expressed as: PAE = PA + ΔPAE For non-yielding (or “restrained”) walls, the total lateral thrust may be similarly calculated based on work by Wood (1973): PKE = PK + ΔPKE Where PA = Static Active Thrust (given previously Table 5.9) PK = Static Restrained Wall Thrust (given previously Table 5.9) ΔPAE = Dynamic Active Thrust Increment = (3/8) kh γH2 ΔPKE = Dynamic Restrained Thrust Increment = kh γH2 TABLE 5.9 EQUIVALENT FLUID UNIT WEIGHTS (pounds per cubic foot) WALL TYPE LEVEL BACKFILL SLOPE BACKFILL 2:1 (HORIZONTAL: VERTICAL) CANTILEVER WALL (YIELDING) 30 48 RESTRAINED WALL 60 75 Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 19 kh = 2/3 Peak Ground Acceleration = 2/3 (PGAM) H = Total Height of the Wall γ = Total Unit Weight of Soil ≈ 135 pounds per cubic foot The increment of dynamic thrust in both cases should be distributed trapezoidally with a line of action located at 0.3H above the bottom of the wall. These values assume non-expansive backfill and free-draining conditions. Measures should be taken to prevent moisture buildup behind all retaining walls. Drainage measures should include free- draining backfill materials and sloped, perforated drains. These drains should discharge to an appropriate off-site location. Figure 4 shows conceptual wall drainage details that may be appropriate for proposed walls at the subject site. Waterproofing should be as specified by the project architect. 5.10 Exterior Flatwork To reduce the potential for cracking in exterior flatwork for non-traffic areas caused by minor movement of subgrade soils and typical concrete shrinkage, it is recommended that such flatwork measure a minimum 4.5 inches thick and be installed with crack-control joints at appropriate spacing as designed by the project architect. Additionally, it is recommended that flatwork be installed with at least No. 3 reinforcing bars on maximum 18-inch centers, each way, at above mid-height of slab but with proper concrete cover, or other reinforcement per the project consultants. Doweling of flatwork joints at critical pathways or similar could also be beneficial in resisting minor subgrade movements. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 20 All subgrades should be prepared according to the earthwork recommendations previously given before placing concrete. Positive drainage should be established and maintained next to all flatwork. Subgrade materials shall be maintained at, or be elevated to, above optimum moisture content prior to concrete placement. 5.11 Pavements If proposed at near grade elevations, pavement sections provided are based on an estimated Resistance “R”-Value and traffic indices, and the assumption that the upper foot of compacted fill subgrade and overlying aggregate base materials are properly compacted to a minimum 95% relative compaction at a minimum of two percent above optimum moisture content (as per ASTM D 1557). Beneath proposed pavement areas, loose or otherwise unsuitable soils are to be removed to the depth of competent native material as recommended in Section 5.2. TABLE 5.11 RECOMMENDED AC OR PCC PAVEMENT SECTION THICKNESSES Traffic Area Assumed Traffic Index Preliminary Subgrade “R”-Value Asphalt Pavements Portland Cement Concrete Pavements On Subgrade (INCHES) AC Thickness (INCHES) CalTrans Class II or Crushed Miscellaneous Aggregate Base Thickness (INCHES) Auto Parking Areas 5.0 20+ 3.0 6.0 6.5 Moderate Drive Areas 6.0 20+ 4.0 9.0 7.0 Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 21 Asphalt paved areas should be designed, constructed, and maintained in accordance with, for example, the recommendations of the Asphalt Institute, or other widely recognized authority. Concrete paved areas should be designed and constructed in accordance with the recommendations of the American Concrete Institute or other widely recognized authority, particularly with regard to thickened edges, joints, and drainage. The Standard Specifications for Public Works construction (“Greenbook”) or Caltrans Standard Specifications may be referenced for pavement materials specifications. 5.12 Drainage Surface runoff should be collected and directed away from improvements by means of appropriate erosion-reducing devices, and positive drainage should be established around proposed improvements. Positive drainage should be directed away from improvements and slope areas at a minimum gradient of two percent for a distance of at least five feet. However, the project civil engineer should evaluate the on-site drainage and make necessary provisions to keep surface water from affecting the site. Generally, CTE recommends against allowing water to infiltrate building pads or adjacent to slopes and improvements. However, it is understood that some agencies are encouraging the use of storm- water cleansing devices. Therefore, if storm water cleansing devices must be used, it is generally recommended that they be underlain by an impervious barrier and that the infiltrate be collected via subsurface piping and discharged off site. If infiltration must occur, water should infiltrate as far away from structural improvements as feasible. Additionally, any reconstructed slopes descending Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 22 from infiltration basins should be equipped with subdrains to collect and discharge accumulated subsurface water (Appendix D contains general or typical details for internal fill slope drainage). 5.13 Slopes Based on observed conditions and anticipated soil strength characteristics, cut and fill slopes should be constructed at ratios of 2:1 (horizontal: vertical) or flatter. These fill slope inclinations should exhibit factors of safety greater than 1.5. Although properly constructed slopes on this site should be grossly stable, the soils will be somewhat erodible. Therefore, runoff water should not be permitted to drain over the edges of slopes unless that water is confined to properly designed and constructed drainage facilities. Erosion-resistant vegetation should be maintained on the face of all slopes. Typically, soils along the top portion of a fill slope face will creep laterally. CTE recommends against building distress- sensitive hardscape improvements within five feet of slope crests. 5.14 Plan Review CTE should be authorized to review the project grading, shoring, and foundation plans, prior to commencement of earthwork to identify potential conflicts with the intent of the geotechnical recommendations. 5.15 Construction Observation The recommendations provided in this report are based on preliminary design information for the proposed construction and the subsurface conditions observed in the explorations performed. The interpolated subsurface conditions should be checked in the field during construction to verify that Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 23 conditions are as anticipated. Foundation recommendations may be revised upon completion of grading and as-built laboratory test results. Recommendations provided in this report are based on the understanding and assumption that CTE will provide the observation and testing services for the project. Earthwork should be observed and tested to verify that grading activities have been performed according to the recommendations contained within this report. CTE should evaluate all footing trenches before reinforcing steel placement. 6.0 LIMITATIONS OF INVESTIGATION The field evaluation, laboratory testing, and geotechnical analysis presented in this report have been conducted according to current engineering practice and the standard of care exercised by reputable geotechnical consultants performing similar tasks in this area. No other warranty, expressed or implied, is made regarding the conclusions, recommendations and opinions expressed in this report. Variations may exist and conditions not observed or described in this report may be encountered during construction. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 24 The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether they are due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. CTE’s conclusions and recommendations are based on an analysis of the observed conditions. If conditions different from those described in this report are encountered, this office should be notified and additional recommendations, if required, will be provided. The opportunity to be of service on this project is appreciated. If you have any questions regarding this report, please do not hesitate to contact the undersigned. Geotechnical Investigation Proposed 5-Unit Residential Subdivision 3980 Highland Drive, Carlsbad, California November 9, 2016 CTE Job No.: 10-12998G \\Esc_server\projects\10-12000 to 10-12999 Projects\10-12998G\Rpt_Geotechnical.doc Page 25 Respectfully submitted, CONSTRUCTION TESTING & ENGINEERING, INC. Dan T. Math, GE #2665 Jay F. Lynch, CEG #1890 Principal Engineer Principal Engineering Geologist Aaron J. Beeby, CEG #2603 Project Geologist AJB/JFL/DTM:nri SITE~ atrick ooJic C Qo,I •~e ~ie fl pe A.BC Time-re prgct,ool c~ Construction Testing & Engineering, Inc. ~c 1441 Montiel Rd S1e 115, Escondido, CA 92026 Ph (760) 746-4955 SITE INDEX MAP PROPOSED 5-UNIT RESIDENTIAL SUBDIVISION 3980 WGHLAND DRIVE CARLSBAD, CALIFORNIA SCALE: AS SHOWN CTE JOB NO.: 10-12998G DATE: 10/16 FIGURE: 1 P-3P-1P-2TP-3QopB-3B-1QopB-2TP-2B-4B-6TP-1B-5B-6Approximate Boring LocationLEGENDP-3Approximate Percolation Test LocationT-3Approximate Test Pit Location(Soil Testers 2005)O'I :I: "O .....:. (0 .... I 0 .... ....... N Q) I... :::, O'I 5 " IX) O> O> N I 0 ;;, 1/l .... u -~ 0 I... a.. O> O> O> N I 0 0 .... 0 0 0 N I 0 ;;, 1/l .... u -~ 0 I... J, I... ~ Q) 1/ll u 1/l ~ . m ;·1 It. _""/ j ------X I RT) I , I APN 207-,130-68 (EXISTING) L ____ _J N 28 "08'06" W (13.33') 6.67' Ii()()()' __ _ ,---rt z ~f--_-:__-::.cr::_-;_~~~ -48" SD--4B" SD---48" ~ ~~~--~-"'-'=-----F--W'~ -.. ~~ ~ 10" S£ IE 6" V -6" -6" v--6" v--6" v--6" v 50' 0 25' 50' Cl~ Construction Testing & Engineering, Inc. ~L. 1441 Montiel Rd ste 115, Escondido, CA 92026 Ph (760} 746--4955 GIOLOGIC/BIPLORlTION LOCATION KAP SCALE: DATE: PROPOSED 5-UNIT SUBDIVISION 1 •=50' 10/16 3980 filGHLAND DRIVE CTE JOB NO.: FIGURE: CARISBAD, CALIFORNIA 10-12998G 2 APPROXIMATESITE LOCATIONLEGENDHISTORIC FAULT DISPLACEMENT (LAST 200 YEARS)HOLOCENE FAULT DISPLACEMENT (DURING PAST 11,700 YEARS)LATE QUATERNARY FAULT DISPLACMENT (DURING PAST 700,000 YEARS) QUATERNARY FAULT DISPLACEMENT (AGE UNDIFFERENTIATED)PREQUATERNARY FAULT DISPLACEMENT (OLDER THAN 1.6 MILLION YEARS)>7.06.5-6.95.5-5.95.0-5.4PERIOD1800- 1869- 1932-1868 1931 2010LAST TWO DIGITS OF M > 6.5EARTHQUAKE YEARMAGNITUDE\ \. OTES: FAULT ACTIVITY MAP OF CAID'ORNIA. 2010, CALIFORNIA GEOLOGIC DATA MAP SERIES MAP NO. 8; EPICRNTRHS or AND AREAS DAMAGED BY ~ 5 CAUFORNIA EARTHQUAKIS, 1800-1999 ADAPTED AF1'D TOPPOZAD!, BRANUII, PETRRSEN, HmSl'ORM, CRAMER, AND REICIILR, 2000, CDIIG MAP Silffl 4-9 REF!RINCE FOR ADDfflONAL EXPLANATION; IIODIPIIID WITH CISN AND USGS SEISIIIC KAPS ~ CTEJNC ~ --·······?-M E Construction Testing & Engineering, Inc. 1441 Montiel Rd ste 115, Escondido, CA 92026 Ph (760) 746-4955 12 0 6 12 ~---I __ I 1 inch = 12 mi. 0 0 0 0 X I ..--. C • • 0 0 0 0 J. 1' MIN 3/4" GRAVEL SURROUNDED BY FILTER FABRIC (MIRAFI 14O N, OR EQUIVALENT) -OR- PREFABRICATED DRAINAGE BOARD RETAINING WALL FINISH GRADE 4" DIA. PERFORATED PVC PIPE (SCHEDULE 40 OR EQUIVALENT). MINIMUM 1% GRADIENT TO SUITABLE OUTLET WALL FOOTING 12" TO 18" OF LOWER PERMEABILITY NATIVE MATERIAL COMPACTED TO 90% RELATIVE COMPACTION SELECT GRANULAR WALL BACKFILL COMPACTED TO 90% RELATIVE COMPACTION WATERPROOFING TO BE SPECIFIED BY ARCHITECT CTE JOB NO: DATE:FIGURE: SCALE: 10/16 NO SCALERETAINING WALL DRAINAGE DETAIL 10-12998G 4 ~ ' V . < > ' -....-r-r........,...,,.~~.....-r-r.,............-1 A ' ~> ~ >' I> 0 d tJ ~~ ► ,. .: 0 ° . ~ 0~ p . . <,. ~ o.., ~,q "'• .l::,. I> • ,, t>t>_ 0 ·o ---o~~ ~&~~~ ~~~ ~~ crP' Construction Testing & Engineering, Inc . ......__J/j;(~ 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 746-4955 APPENDIX A REFERENCES REFERENCES 1. American Society for Civil Engineers, 2010, “Minimum Design Loads for Buildings and Other Structures,” ASCE/SEI 7-10. 2. ASTM, 2002, “Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort,” Volume 04.08 3. Blake, T.F., 2000, “EQFAULT,” Version 3.00b, Thomas F. Blake Computer Services and Software. 4. California Building Code, 2013, “California Code of Regulations, Title 24, Part 2, Volume 2 of 2,” California Building Standards Commission, published by ICBO, June. 5. California Division of Mines and Geology, CD 2000-003 “Digital Images of Official Maps of Alquist-Priolo Earthquake Fault Zones of California, Southern Region,” compiled by Martin and Ross. 6. California Emergency Management Agency/California Geological Survey, “Tsunami Inundation Maps for Emergency Planning. 7. County of San Diego Department of Environmental Health Land and Water Quality Division, 2010, Design Manual for Onsite Wastewater Treatment Systems dated March 22 updated November 25, 2013. 8. Frankel, A.D., Petersen, M.D., Mueller, C.S., Haller, K.M., Wheeler, R.L., Leyendecker, E.V., Wesson, R. L., Harmsen, S.C., Cramer, C.H., Perkins, D.M., Rukstales,K.S.,2002, Documentation for the 2002 update of the National Seismic Hazard Maps: U.S. Geological Survey Open-File Report 2002-420, 39p 9. Hart, Earl W., Revised 2007, “Fault-Rupture Hazard Zones in California, Alquist Priolo, Special Studies Zones Act of 1972,” California Division of Mines and Geology, Special Publication 42. 10. Jennings, Charles W., 1994, “Fault Activity Map of California and Adjacent Areas” with Locations and Ages of Recent Volcanic Eruptions. 11. Kennedy, M.P. and Tan, S.S., 2008, “Geologic Map of the Oceanside 30’ x 60’ Quadrangle, California”, California Geological Survey, Map No. 2, Plate 1 of 2. 12. Reichle, M., Bodin, P., and Brune, J., 1985, The June 1985 San Diego Bay Earthquake swarm [abs.]: EOS, v. 66, no. 46, p.952. 13. SEAOC, Blue Book-Seismic Design Recommendations, “Seismically Induced Lateral Earth Pressures on Retaining Structures and Basement Walls,” Article 09.10.010, October 2013. 14. Seed, H.B., and R.V. Whitman, 1970, “Design of Earth Retaining Structures for Dynamic Loads,” in Proceedings, ASCE Specialty Conference on Lateral Stresses in the Ground and Design of Earth-Retaining Structures, pp. 103-147, Ithaca, New York: Cornell University. 15. Simons, R.S., 1979, Instrumental Seismicity of the San Diego area, 1934-1978, in Abbott, P.L. and Elliott, W.J., eds., Earthquakes and other perils, San Diego region: San Diego Association of Geologists, prepared for Geological Society of America field trip, November 1979, p.101-105. 16. Soil Testers, 2005, Site Inspection, Proposed Residential Building Site, 3980 Highland Avenue, City of Carlsbad, Subject: Filr No. 1106F3-05, dated September 2. 17. Tan, S. S., and Giffen, D. G., 1995, “Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California: Oceanside and San Luis Rey Quadrangles, Landslide Hazard Identification Map No. 35”, California Department of Conservation, Division of Mines and Geology, Open-File Report 95-04, State of California, Division of Mines and Geology, Sacramento, California. 18. Wood, J.H. 1973, Earthquake-Induced Soil Pressures on Structures, Report EERL 73-05. Pasadena: California Institute of Technology. APPENDIX B EXPLORATION LOGS DEFINITION OF TERMS PRIMARY DIVISIONS SYMBOLS SECONDARY DIVISIONS WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES LITTLE OR NO FINES POORLY GRADED GRAVELS OR GRAVEL SAND MIXTURES, LITTLE OF NO FINES SILTY GRAVELS, GRAVEL-SAND-SILT MIXTURES, NON-PLASTIC FINES CLAYEY GRAVELS, GRAVEL-SAND-CLAY MIXTURES, PLASTIC FINES WELL GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES POORLY GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES SILTY SANDS, SAND-SILT MIXTURES, NON-PLASTIC FINES CLAYEY SANDS, SAND-CLAY MIXTURES, PLASTIC FINES INORGANIC SILTS, VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS, SLIGHTLY PLASTIC CLAYEY SILTS INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY, SANDY, SILTS OR LEAN CLAYS ORGANIC SILTS AND ORGANIC CLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SANDY OR SILTY SOILS, ELASTIC SILTS INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTY CLAYS PEAT AND OTHER HIGHLY ORGANIC SOILS GRAIN SIZES GRAVEL SAND COARSE FINE COARSE MEDIUM FINE 12" 3" 3/4" 4 10 40 200 CLEAR SQUARE SIEVE OPENING U.S. STANDARD SIEVE SIZE ADDITIONAL TESTS (OTHER THAN TEST PIT AND BORING LOG COLUMN HEADINGS) MAX- Maximum Dry Density PM- Permeability PP- Pocket Penetrometer GS- Grain Size Distribution SG- Specific Gravity WA- Wash Analysis SE- Sand Equivalent HA- Hydrometer Analysis DS- Direct Shear EI- Expansion Index AL- Atterberg Limits UC- Unconfined Compression CHM- Sulfate and Chloride RV- R-Value MD- Moisture/Density Content , pH, Resistivity CN- Consolidation M- Moisture COR - Corrosivity CP- Collapse Potential SC- Swell Compression SD- Sample Disturbed HC- Hydrocollapse OI- Organic Impurities REM- Remolded FIGURE: BL1 GW SILTS AND CLAYS LIQUID LIMIT ISLESS THAN 50 SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50 SANDS MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE GRAVELS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE CLEAN GRAVELS < 5% FINES GRAVELS WITH FINES CLEAN SANDS < 5% FINES SANDSWITH FINESCOARSE GRAINED SOILSMORE THAN HALF OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZEGP GM GC SW SP SM SC ML CL OL MH CH OH PTFINE GRAINED SOILSMORE THAN HALF OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZEHIGHLY ORGANIC SOILS SILTS AND CLAYSCOBBLESCOBBLESBOULDERS Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 746-4955 PROJECT:DRILLER:SHEET:of CTE JOB NO:DRILL METHOD:DRILLING DATE: LOGGED BY:SAMPLE METHOD:ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/FootDry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogBORING LEGEND Laboratory Tests DESCRIPTION Block or Chunk Sample Bulk Sample Standard Penetration Test Modified Split-Barrel Drive Sampler (Cal Sampler) Thin Walled Army Corp. of Engineers Sample Groundwater Table Soil Type or Classification Change ??????? Formation Change [(Approximate boundaries queried (?)] "SM"Quotes are placed around classifications where the soilsexist in situ as bedrock FIGURE: BL2 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 746-4955 -0 - -~ - --- -X - -- -5- - - - - ~'" - - - - .... 10-- - -I -- - - -I - - - -15- - - - - ~ - - - - ~----------------------------------------------------------------------- 20---------------- -\_ - - - - - - 25- - - I PROJECT:SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/6"Dry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogDESCRIPTION "SM" Total Depth: 4' (Refusal in medium dense Paralic Deposits)No Groundwater Encountered 1 10-12998G HAND AUGER 10/11/2016 5-UNIT SUBDIVISION DRILLER: AJB 1 AJB BULK ~162 FEET BORING: B-1 Laboratory Tests QUATERNARY OLD PARALIC DEPOSITS:Medium dense, slightly moist, light reddish brown, silty fine to medium grained SANDSTONE, oxidized, massive porous. GS B-1 0 5 10 15 20 25 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I PROJECT:SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/6"Dry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogDESCRIPTION "SC/SM" Total Depth: 2' (Refusal in medium dense Paralic Deposits)No Groundwater Encountered 5-UNIT SUBDIVISION DRILLER:AJB 1 1 10-12998G HAND AUGER 10/11/2016 AJB BULK ~153 FEET BORING: B-2 Laboratory Tests QUATERNARY OLD PARALIC DEPOSITS:Medium dense, slightly moist, reddish brown, silty fine to mediumgrained SANDSTONE, oxidized, massive porous. B-2 0 5 10 15 20 25 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I PROJECT:SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/6"Dry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogDESCRIPTION "SC/SM" Total Depth: 2' (Refusal in medium dense Paralic Deposits)No Groundwater Encountered 5-UNIT SUBDIVISION DRILLER:AJB 1 1 10-12998G HAND AUGER 10/11/2016 AJB BULK ~157 FEET BORING: B-3 Laboratory Tests QUATERNARY OLD PARALIC DEPOSITS:Medium dense, slightly moist, light reddish brown, silty fine to medium grained SANDSTONE, oxidized, massive, porous. B-3 0 5 10 15 20 25 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I PROJECT:SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/6"Dry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogDESCRIPTION SM "SM/SC" Total Depth: 2' (Refusal in medium dense Paralic Deposits)No Groundwater Encountered 5-UNIT SUBDIVISION DRILLER:AJB 1 1 10-12998G HAND AUGER 10/11/2016 AJB BULK ~138 FEET BORING: B-4 Laboratory Tests QUATERNARY UNDOCUMENTED FILL:Loose, dry, brown, silty fine grained SAND, roots throughout.QUATERNARY OLD PARALIC DEPOSITS:CHMMedium dense, slightly moist, reddish brown, fine to mediumgrained SANDSTONE, massive, porous, oxidized, moderately B-4 cemented. 0 5 10 15 20 25 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 - - -i -"' - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I PROJECT:SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/6"Dry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogDESCRIPTION "SC/SM" Total Depth: 2' (Refusal in medium dense Paralic Deposits)No Groundwater Encountered 5-UNIT SUBDIVISION DRILLER:AJB 1 1 10-12998G HAND AUGER 10/11/2016 AJB BULK ~132 FEET BORING: B-5 Laboratory Tests QUATERNARY OLD PARALIC DEPOSITS:Medium dense, slightly moist, reddish brown, silty to clayey fine to medium grained SANDSTONE, oxidized, massive, porous. B-5 0 5 10 15 20 25 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I PROJECT:SHEET: of CTE JOB NO: DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION:Depth (Feet)Bulk SampleDriven TypeBlows/6"Dry Density (pcf)Moisture (%)U.S.C.S. SymbolGraphic LogDESCRIPTION "SC/SM" "ML" Total Depth: 7' (Refusal in medium dense Paralic Deposits)No Groundwater Encountered 5-UNIT SUBDIVISION DRILLER:AJB 1 1 10-12998G HAND AUGER 10/11/2016 AJB BULK ~134 FEET BORING: B-6 Laboratory Tests QUATERNARY OLD PARALIC DEPOSITS:Medium dense, dry to slightly moist, reddish brown, clayey tosilty fine to medium grained SANDSTONE, oxidized, massive, porous, burrowed in the upper 0.5 feet. Stiff, moist, dark reddish brown, fine grained sandy SILTSTONE,massive, oxidized.GS B-6 0 5 10 15 20 25 Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 -----t----t------~~----------------------------- - - - - - - - - - -- -----t----t--------------------------------------1 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I APPENDIX C LABORATORY METHODS AND RESULTS APPENDIX C LABORATORY METHODS AND RESULTS Laboratory Testing Program Laboratory tests were performed on representative soil samples to detect their relative engineering properties. Tests were performed following test methods of the American Society for Testing Materials or other accepted standards. The following presents a brief description of the various test methods used. Classification Soils were classified visually according to the Unified Soil Classification System. Visual classifications were supplemented by laboratory testing of selected samples according to ASTM D2487. The soil classifications are shown on the Exploration Logs in Appendix B. Particle-Size Analysis Particle-size analyses were performed on selected representative samples according to ASTM D 422. Chemical Analysis Soil materials were collected with sterile sampling equipment and tested for Sulfate and Chloride content, pH, Corrosivity, and Resistivity. LOCATION RESULTS ppm B-4 110.2 LOCATION RESULTS ppm B-4 43.2 LOCATION RESULTS B-4 6.73 LOCATION RESULTS ohms-cm B-4 5010 DEPTH 0-2 (feet) 0-2 RESISTIVITY CALIFORNIA TEST 424 DEPTH (feet) CHLORIDE DEPTH (feet) 0-2 p.H. SULFATE DEPTH (feet) 0-2 LABORATORY SUMMARY CTE JOB NO. 10-12998G Construction Testing & Engineering, Inc. 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 7 46-4955 PARTICLE SIZE ANALYSISSample Designation Sample Depth (feet) Symbol Liquid Limit (%) Plasticity Index ClassificationB-10-400SMB-6 4.9-700MLCTE JOB NUMBER: 10-12998GFIGURE: C-101020304050607080901000.0010.010.1110100PERCENT PASSING (%)PARTICLE SIZE (mm)U. S. STANDARD SIEVE SIZE2"1"3/4"1/2"3/8"481016203040501002001.5"------- ---- - - -~ ~ ----r--~, \ ' \ \ .... ' "'-'~ \ ■ t \ \ \ " r-,~ • ~ Construction Testing & Engineering, Inc. • CT~c 1441 Montiel Rd Ste 115, Escondido, CA 92026 Ph (760) 746-4955 ■ APPENDIX D STANDARD SPECIFICATIONS FOR GRADING Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 1 of 26 Page D-1 Section 1 - General Construction Testing & Engineering, Inc. presents the following standard recommendations for grading and other associated operations on construction projects. These guidelines should be considered a portion of the project specifications. Recommendations contained in the body of the previously presented soils report shall supersede the recommendations and or requirements as specified herein. The project geotechnical consultant shall interpret disputes arising out of interpretation of the recommendations contained in the soils report or specifications contained herein. Section 2 - Responsibilities of Project Personnel The geotechnical consultant should provide observation and testing services sufficient to general conformance with project specifications and standard grading practices. The geotechnical consultant should report any deviations to the client or his authorized representative. The Client should be chiefly responsible for all aspects of the project. He or his authorized representative has the responsibility of reviewing the findings and recommendations of the geotechnical consultant. He shall authorize or cause to have authorized the Contractor and/or other consultants to perform work and/or provide services. During grading the Client or his authorized representative should remain on-site or should remain reasonably accessible to all concerned parties in order to make decisions necessary to maintain the flow of the project. The Contractor is responsible for the safety of the project and satisfactory completion of all grading and other associated operations on construction projects, including, but not limited to, earth work in accordance with the project plans, specifications and controlling agency requirements. Section 3 - Preconstruction Meeting A preconstruction site meeting should be arranged by the owner and/or client and should include the grading contractor, design engineer, geotechnical consultant, owner’s representative and representatives of the appropriate governing authorities. Section 4 - Site Preparation The client or contractor should obtain the required approvals from the controlling authorities for the project prior, during and/or after demolition, site preparation and removals, etc. The appropriate approvals should be obtained prior to proceeding with grading operations. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 2 of 26 Page D-2 Clearing and grubbing should consist of the removal of vegetation such as brush, grass, woods, stumps, trees, root of trees and otherwise deleterious natural materials from the areas to be graded. Clearing and grubbing should extend to the outside of all proposed excavation and fill areas. Demolition should include removal of buildings, structures, foundations, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, mining shafts, tunnels, etc.) and other man-made surface and subsurface improvements from the areas to be graded. Demolition of utilities should include proper capping and/or rerouting pipelines at the project perimeter and cutoff and capping of wells in accordance with the requirements of the governing authorities and the recommendations of the geotechnical consultant at the time of demolition. Trees, plants or man-made improvements not planned to be removed or demolished should be protected by the contractor from damage or injury. Debris generated during clearing, grubbing and/or demolition operations should be wasted from areas to be graded and disposed off-site. Clearing, grubbing and demolition operations should be performed under the observation of the geotechnical consultant. Section 5 - Site Protection Protection of the site during the period of grading should be the responsibility of the contractor. Unless other provisions are made in writing and agreed upon among the concerned parties, completion of a portion of the project should not be considered to preclude that portion or adjacent areas from the requirements for site protection until such time as the entire project is complete as identified by the geotechnical consultant, the client and the regulating agencies. Precautions should be taken during the performance of site clearing, excavations and grading to protect the work site from flooding, ponding or inundation by poor or improper surface drainage. Temporary provisions should be made during the rainy season to adequately direct surface drainage away from and off the work site. Where low areas cannot be avoided, pumps should be kept on hand to continually remove water during periods of rainfall. Rain related damage should be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress and other adverse conditions as determined by the geotechnical consultant. Soil adversely affected should be classified as unsuitable materials and should be subject to overexcavation and replacement with compacted fill or other remedial grading as recommended by the geotechnical consultant. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 3 of 26 Page D-3 The contractor should be responsible for the stability of all temporary excavations. Recommendations by the geotechnical consultant pertaining to temporary excavations (e.g., backcuts) are made in consideration of stability of the completed project and, therefore, should not be considered to preclude the responsibilities of the contractor. Recommendations by the geotechnical consultant should not be considered to preclude requirements that are more restrictive by the regulating agencies. The contractor should provide during periods of extensive rainfall plastic sheeting to prevent unprotected slopes from becoming saturated and unstable. When deemed appropriate by the geotechnical consultant or governing agencies the contractor shall install checkdams, desilting basins, sand bags or other drainage control measures. In relatively level areas and/or slope areas, where saturated soil and/or erosion gullies exist to depths of greater than 1.0 foot; they should be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where affected materials exist to depths of 1.0 foot or less below proposed finished grade, remedial grading by moisture conditioning in-place, followed by thorough recompaction in accordance with the applicable grading guidelines herein may be attempted. If the desired results are not achieved, all affected materials should be overexcavated and replaced as compacted fill in accordance with the slope repair recommendations herein. If field conditions dictate, the geotechnical consultant may recommend other slope repair procedures. Section 6 - Excavations 6.1 Unsuitable Materials Materials that are unsuitable should be excavated under observation and recommendations of the geotechnical consultant. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic compressible natural soils and fractured, weathered, soft bedrock and nonengineered or otherwise deleterious fill materials. Material identified by the geotechnical consultant as unsatisfactory due to its moisture conditions should be overexcavated; moisture conditioned as needed, to a uniform at or above optimum moisture condition before placement as compacted fill. If during the course of grading adverse geotechnical conditions are exposed which were not anticipated in the preliminary soil report as determined by the geotechnical consultant additional exploration, analysis, and treatment of these problems may be recommended. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 4 of 26 Page D-4 6.2 Cut Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent cut slopes should not be steeper than 2:1 (horizontal: vertical). The geotechnical consultant should observe cut slope excavation and if these excavations expose loose cohesionless, significantly fractured or otherwise unsuitable material, the materials should be overexcavated and replaced with a compacted stabilization fill. If encountered specific cross section details should be obtained from the Geotechnical Consultant. When extensive cut slopes are excavated or these cut slopes are made in the direction of the prevailing drainage, a non-erodible diversion swale (brow ditch) should be provided at the top of the slope. 6.3 Pad Areas All lot pad areas, including side yard terrace containing both cut and fill materials, transitions, located less than 3 feet deep should be overexcavated to a depth of 3 feet and replaced with a uniform compacted fill blanket of 3 feet. Actual depth of overexcavation may vary and should be delineated by the geotechnical consultant during grading, especially where deep or drastic transitions are present. For pad areas created above cut or natural slopes, positive drainage should be established away from the top-of-slope. This may be accomplished utilizing a berm drainage swale and/or an appropriate pad gradient. A gradient in soil areas away from the top-of-slopes of 2 percent or greater is recommended. Section 7 - Compacted Fill All fill materials should have fill quality, placement, conditioning and compaction as specified below or as approved by the geotechnical consultant. 7.1 Fill Material Quality Excavated on-site or import materials which are acceptable to the geotechnical consultant may be utilized as compacted fill, provided trash, vegetation and other deleterious materials are removed prior to placement. All import materials anticipated for use on-site should be sampled tested and approved prior to and placement is in conformance with the requirements outlined. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 5 of 26 Page D-5 Rocks 12 inches in maximum and smaller may be utilized within compacted fill provided sufficient fill material is placed and thoroughly compacted over and around all rock to effectively fill rock voids. The amount of rock should not exceed 40 percent by dry weight passing the 3/4-inch sieve. The geotechnical consultant may vary those requirements as field conditions dictate. Where rocks greater than 12 inches but less than four feet of maximum dimension are generated during grading, or otherwise desired to be placed within an engineered fill, special handling in accordance with the recommendations below. Rocks greater than four feet should be broken down or disposed off-site. 7.2 Placement of Fill Prior to placement of fill material, the geotechnical consultant should observe and approve the area to receive fill. After observation and approval, the exposed ground surface should be scarified to a depth of 6 to 8 inches. The scarified material should be conditioned (i.e. moisture added or air dried by continued discing) to achieve a moisture content at or slightly above optimum moisture conditions and compacted to a minimum of 90 percent of the maximum density or as otherwise recommended in the soils report or by appropriate government agencies. Compacted fill should then be placed in thin horizontal lifts not exceeding eight inches in loose thickness prior to compaction. Each lift should be moisture conditioned as needed, thoroughly blended to achieve a consistent moisture content at or slightly above optimum and thoroughly compacted by mechanical methods to a minimum of 90 percent of laboratory maximum dry density. Each lift should be treated in a like manner until the desired finished grades are achieved. The contractor should have suitable and sufficient mechanical compaction equipment and watering apparatus on the job site to handle the amount of fill being placed in consideration of moisture retention properties of the materials and weather conditions. When placing fill in horizontal lifts adjacent to areas sloping steeper than 5:1 (horizontal: vertical), horizontal keys and vertical benches should be excavated into the adjacent slope area. Keying and benching should be sufficient to provide at least six-foot wide benches and a minimum of four feet of vertical bench height within the firm natural ground, firm bedrock or engineered compacted fill. No compacted fill should be placed in an area after keying and benching until the geotechnical consultant has reviewed the area. Material generated by the benching operation should be moved sufficiently away from Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 6 of 26 Page D-6 the bench area to allow for the recommended review of the horizontal bench prior to placement of fill. Within a single fill area where grading procedures dictate two or more separate fills, temporary slopes (false slopes) may be created. When placing fill adjacent to a false slope, benching should be conducted in the same manner as above described. At least a 3-foot vertical bench should be established within the firm core of adjacent approved compacted fill prior to placement of additional fill. Benching should proceed in at least 3-foot vertical increments until the desired finished grades are achieved. Prior to placement of additional compacted fill following an overnight or other grading delay, the exposed surface or previously compacted fill should be processed by scarification, moisture conditioning as needed to at or slightly above optimum moisture content, thoroughly blended and recompacted to a minimum of 90 percent of laboratory maximum dry density. Where unsuitable materials exist to depths of greater than one foot, the unsuitable materials should be over-excavated. Following a period of flooding, rainfall or overwatering by other means, no additional fill should be placed until damage assessments have been made and remedial grading performed as described herein. Rocks 12 inch in maximum dimension and smaller may be utilized in the compacted fill provided the fill is placed and thoroughly compacted over and around all rock. No oversize material should be used within 3 feet of finished pad grade and within 1 foot of other compacted fill areas. Rocks 12 inches up to four feet maximum dimension should be placed below the upper 10 feet of any fill and should not be closer than 15 feet to any slope face. These recommendations could vary as locations of improvements dictate. Where practical, oversized material should not be placed below areas where structures or deep utilities are proposed. Oversized material should be placed in windrows on a clean, overexcavated or unyielding compacted fill or firm natural ground surface. Select native or imported granular soil (S.E. 30 or higher) should be placed and thoroughly flooded over and around all windrowed rock, such that voids are filled. Windrows of oversized material should be staggered so those successive strata of oversized material are not in the same vertical plane. It may be possible to dispose of individual larger rock as field conditions dictate and as recommended by the geotechnical consultant at the time of placement. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 7 of 26 Page D-7 The contractor should assist the geotechnical consultant and/or his representative by digging test pits for removal determinations and/or for testing compacted fill. The contractor should provide this work at no additional cost to the owner or contractor's client. Fill should be tested by the geotechnical consultant for compliance with the recommended relative compaction and moisture conditions. Field density testing should conform to ASTM Method of Test D 1556-00, D 2922-04. Tests should be conducted at a minimum of approximately two vertical feet or approximately 1,000 to 2,000 cubic yards of fill placed. Actual test intervals may vary as field conditions dictate. Fill found not to be in conformance with the grading recommendations should be removed or otherwise handled as recommended by the geotechnical consultant. 7.3 Fill Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent fill slopes should not be steeper than 2:1 (horizontal: vertical). Except as specifically recommended in these grading guidelines compacted fill slopes should be over-built two to five feet and cut back to grade, exposing the firm, compacted fill inner core. The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved, the existing slopes should be overexcavated and reconstructed under the guidelines of the geotechnical consultant. The degree of overbuilding shall be increased until the desired compacted slope surface condition is achieved. Care should be taken by the contractor to provide thorough mechanical compaction to the outer edge of the overbuilt slope surface. At the discretion of the geotechnical consultant, slope face compaction may be attempted by conventional construction procedures including backrolling. The procedure must create a firmly compacted material throughout the entire depth of the slope face to the surface of the previously compacted firm fill intercore. During grading operations, care should be taken to extend compactive effort to the outer edge of the slope. Each lift should extend horizontally to the desired finished slope surface or more as needed to ultimately established desired grades. Grade during construction should not be allowed to roll off at the edge of the slope. It may be helpful to elevate slightly the outer edge of the slope. Slough resulting from the placement of individual lifts should not be allowed to drift down over previous lifts. At intervals not Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 8 of 26 Page D-8 exceeding four feet in vertical slope height or the capability of available equipment, whichever is less, fill slopes should be thoroughly dozer trackrolled. For pad areas above fill slopes, positive drainage should be established away from the top-of-slope. This may be accomplished using a berm and pad gradient of at least two percent. Section 8 - Trench Backfill Utility and/or other excavation of trench backfill should, unless otherwise recommended, be compacted by mechanical means. Unless otherwise recommended, the degree of compaction should be a minimum of 90 percent of the laboratory maximum density. Within slab areas, but outside the influence of foundations, trenches up to one foot wide and two feet deep may be backfilled with sand and consolidated by jetting, flooding or by mechanical means. If on-site materials are utilized, they should be wheel-rolled, tamped or otherwise compacted to a firm condition. For minor interior trenches, density testing may be deleted or spot testing may be elected if deemed necessary, based on review of backfill operations during construction. If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, the contractor may elect the utilization of light weight mechanical compaction equipment and/or shading of the conduit with clean, granular material, which should be thoroughly jetted in-place above the conduit, prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate, upon review of the geotechnical consultant at the time of construction. In cases where clean granular materials are proposed for use in lieu of native materials or where flooding or jetting is proposed, the procedures should be considered subject to review by the geotechnical consultant. Clean granular backfill and/or bedding are not recommended in slope areas. Section 9 - Drainage Where deemed appropriate by the geotechnical consultant, canyon subdrain systems should be installed in accordance with CTE’s recommendations during grading. Typical subdrains for compacted fill buttresses, slope stabilization or sidehill masses, should be installed in accordance with the specifications. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 9 of 26 Page D-9 Roof, pad and slope drainage should be directed away from slopes and areas of structures to suitable disposal areas via non-erodible devices (i.e., gutters, downspouts, and concrete swales). For drainage in extensively landscaped areas near structures, (i.e., within four feet) a minimum of 5 percent gradient away from the structure should be maintained. Pad drainage of at least 2 percent should be maintained over the remainder of the site. Drainage patterns established at the time of fine grading should be maintained throughout the life of the project. Property owners should be made aware that altering drainage patterns could be detrimental to slope stability and foundation performance. Section 10 - Slope Maintenance 10.1 - Landscape Plants To enhance surficial slope stability, slope planting should be accomplished at the completion of grading. Slope planting should consist of deep-rooting vegetation requiring little watering. Plants native to the southern California area and plants relative to native plants are generally desirable. Plants native to other semi-arid and arid areas may also be appropriate. A Landscape Architect should be the best party to consult regarding actual types of plants and planting configuration. 10.2 - Irrigation Irrigation pipes should be anchored to slope faces, not placed in trenches excavated into slope faces. Slope irrigation should be minimized. If automatic timing devices are utilized on irrigation systems, provisions should be made for interrupting normal irrigation during periods of rainfall. 10.3 - Repair As a precautionary measure, plastic sheeting should be readily available, or kept on hand, to protect all slope areas from saturation by periods of heavy or prolonged rainfall. This measure is strongly recommended, beginning with the period prior to landscape planting. If slope failures occur, the geotechnical consultant should be contacted for a field review of site conditions and development of recommendations for evaluation and repair. If slope failures occur as a result of exposure to period of heavy rainfall, the failure areas and currently unaffected areas should be covered with plastic sheeting to protect against additional saturation. Appendix D Standard Specifications for Grading STANDARD SPECIFICATIONS OF GRADING Page 10 of 26 Page D-10 In the accompanying Standard Details, appropriate repair procedures are illustrated for superficial slope failures (i.e., occurring typically within the outer one foot to three feet of a slope face). FINISH CUT SLOPE ---- 5'MIN ----------- BENCHING FILL OVER NATURAL FILL SLOPE 10' TYPICAL SURFACE OF FIRM EARTH MATERIAL 15' MIN. {INCLINED 2% MIN. INTO SLOPE) BENCHING FILL OVER CUT FINISH FILL SLOPE SURFACE OF FIRM EARTH MATERIAL 15' MIN OR STABILITY EQUIVALENT PER SOIL ENGINEERING (INCLINED 2% MIN. INTO SLOPE) NOTTO SCALE BENCHING FOR COMPACTED FILL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 11 of 26 -- --- MINIMUM DOWNSLOPE KEY DEPTH TOE OF SLOPE SHOWN ON GRADING PLAN FILL __ -------------- -------~ ...... --~ -__ .,,,,,. ~'\~~~ .,,,,,..,,,,,..,,,,,. .,,,,,. ~~~ .,,,,,..,,,,,. .,,,,,..,,,,,..,,,,,. ~~~~ .,,,,,..,,,,,. _.,,,,,. :"\~~\.; .,,,,,..,,,,,. _.,,,,,. ~sux ~_.,,,,,. _________ _ ---\j .,,,,,. .,,,,,. .,,,,,. .,,,,,. 1 O' TYPICAL BENCH // .,,,,,. .,,,,,. .,,,,,. WIDTH VARIES 4' ~1 .,,,,,..,,,,,..,,,,,. / 1 __ .,,,,,..,,,,,. COMPETENT EARTH / --MATERIAL - 2% MIN --- 15' MINIMUM BASE KEY WIDTH TYPICAL BENCH HEIGHT PROVIDE BACKDRAIN AS REQUIRED PER RECOMMENDATIONS OF SOILS ENGINEER DURING GRADING WHERE NATURAL SLOPE GRADIENT IS 5:1 OR LESS, BENCHING IS NOT NECESSARY. FILL IS NOT TO BE PLACED ON COMPRESSIBLE OR UNSUITABLE MATERIAL. NOT TO SCALE FILL SLOPE ABOVE NATURAL GROUND DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 12 of 26 U) ~ z CJ ► Jl CJ U) ""CJ ""CJ m Ill(") cc -CD Jl ...I.(") w► 0 :::! -h 0 I\) z C) U) "Tl 0 Jl Ci) ~ CJ z Ci) -REMOVE ALL TOPSOIL, COLLUVIUM, AND CREEP MATERIAL FROM TRANSITION CUT/FILL CONTACT SHOWN ON GRADING PLAN CUT/FILL CONTACT SHOWN ON "AS-BUILT" NATURAL __ TOPOGRAP~Y __ ---------_ --CUT SLOPE* --------- - ---;_? ~€.\\!lo\J€. FILL ------:::-ul<l~ocl'.€ --------col.l--\)v' ...... --,o?so\\._:.. - - - - ---1 rr~---------14'TYPIGAL I ---2%MIN --15' MINIMUM NOTTO SCALE 10' TYPICAL BEDROCK OR APPROVED FOUNDATION MATERIAL *NOTE: CUT SLOPE PORTION SHOULD BE MADE PRIOR TO PLACEMENT OF FILL FILL SLOPE ABOVE CUT SLOPE DETAIL ---- [ SURFACEOF COMPETENT MATERIAL --~-------------~ -..... ' ,,,,,, .,,,,,. \'\ COMPACTED FILL /'/ \\ // \ / TYPICAL BENCHING \ \ / \' / / ....___ , _,,,,,, A...-~ SEE DETAIL BELOW MINIMUM 9 FT3 PER LINEAR FOOT OF APPROVED FILTER MATERIAL CAL TRANS CLASS 2 PERMEABLE MATERIAL FILTER MATERIAL TO MEET FOLLOWING SPECIFICATION OR APPROVED EQUAL: ' / REMOVE UNSUITABLE DETAIL 14" MATERIAL INCLINE TOWARD DRAIN AT 2% GRADIENT MINIMUM MINIMUM 4" DIAMETER APPROVED PERFORATED PIPE (PERFORATIONS DOWN) 6" FILTER MATERIAL BEDDING SIEVE SIZE PERCENTAGE PASSING APPROVED PIPE TO BE SCHEDULE 40 POLY-VINYL-CHLORIDE (P.V.C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 psi 1" ¾" ¾" NO.4 NO.8 NO. 30 NO. 50 NO. 200 100 90-100 40-100 25-40 18-33 5-15 0-7 0-3 PIPE DIAMETER TO MEET THE FOLLOWING CRITERIA, SUBJECT TO FIELD REVIEW BASED ON ACTUAL GEOTECHNICAL CONDITIONS ENCOUNTERED DURING GRADING LENGTH OF RUN NOTTO SCALE INITIAL 500' 500' TO 1500' > 1500' PIPE DIAMETER 4" 6" 8" TYPICAL CANYON SUBDRAIN DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 14 of 26 TYPICAL BENCHING CANYON SUBDRAIN DETAILS --""' ----,, ,,,,,..,,, [ SURFACEOF COMPETENT MATERIAL ,'' COMPACTED FILL / ~ \\ // \ / \ \ / ,, // --,_,,,,,. __ ..._ ' / REMOVE UNSUITABLE MATERIAL SEE DETAILS BELOW TRENCH DETAILS 6" MINIMUM OVERLAP INCLINE TOWARD DRAIN AT 2% GRADIENT MINIMUM OPTIONAL V-DITCH DETAIL MINIMUM 9 FP PER LINEAR FOOT OF APPROVED DRAIN MATERIAL MIRAFI 140N FABRIC OR APPROVED EQUAL 6" MINIMUM OVERLAP --------0 24" MINIMUM MIRAFI 140N FABRIC OR APPROVED EQUAL APPROVED PIPE TO BE SCHEDULE 40 POLY- VINYLCHLORIDE (P.V.C.) 24" MINIMUM MINIMUM 9 FP PER LINEAR FOOT OF APPROVED DRAIN MATERIAL OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 PSI. DRAIN MATERIAL TO MEET FOLLOWING SPECIFICATION OR APPROVED EQUAL: PIPE DIAMETER TO MEET THE FOLLOWING CRITERIA, SUBJECT TO FIELD REVIEW BASED ON ACTUAL GEOTECHNICAL CONDITIONS ENCOUNTERED DURING GRADING SIEVE SIZE 1 ½" 1" ¾" ¾" NO. 200 PERCENTAGE PASSING 88-100 5-40 0-17 0-7 0-3 LENGTH OF RUN INITIAL 500' 500' TO 1500' > 1500' NOT TO SCALE GEOFABRIC SUBDRAIN STANDARD SPECIFICATIONS FOR GRADING Page 15 of 26 PIPE DIAMETER 4" 6" 8" FRONT VIEW CONCRETE CUT-OFF WALL SUBDRAIN PIPE SIDE VIEW -•. . . _,.. -, .. -.. -. .-, .... , ... , l!trr.'' ltt.'' t..'' ... . ' 6" Min. .... . ' .. ----~---· ·-·-~ 6" Min. 24" Min. 6" Min. ~ 12" Min.~ 6" Min. CONCRETE CUT-OFF WALL __ _..,• .• -:..►.-.. • . ' ... ' 6" Min . -... -... SOILD SUBDRAIN PIPE •.-, ., "' 'i "' ' PERFORATED SUBDRAIN PIPE . ' . ' . . . . . . NOT TO SCALE RECOMMENDED SUBDRAIN CUT-OFF WALL STANDARD SPECIFICATIONS FOR GRADING Page 16 of 26 FRONT VIEW SUBDRAIN OUTLET PIPE (MINIMUM 4" DIAMETER) SIDE VIEW ALL BACKFILL SHOULD BE COMPACTED IN CONFORMANCE WITH PROJECT SPECIFICATIONS. COMPACTION EFFORT SHOULD NOT DAMAGE STRUCTURE I • ' -• I I ► -'► -'► - , ,·b.. ,·brr.. ,·brr. • .!,. • ' .... • ' i" . ' ► -'► -'►-, ,, • b. ' ' • b. • ' ' brr. • .:i.,,6,,6,, -... . -.... -.... ► - , ► - , ►-, ,, I b. I 1, I b. I ' I brr. I .i0rr..,.i0rr..,.6.., t---24" Min. >----24" Min. NOTE: HEADWALL SHOULD OUTLET AT TOE OF SLOPE OR INTO CONTROLLED SURFACE DRAINAGE DEVICE ALL DISCHARGE SHOULD BE CONTROLLED THIS DETAIL IS A MINIMUM DESIGN AND MAY BE MODIFIED DEPENDING UPON ENCOUNTERED CONDITIONS AND LOCAL REQUIREMENTS NOT TO SCALE 24" Min. 12" TYPICAL SUBDRAIN OUTLET HEADWALL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 17 of 26 4" DIAMETER PERFORATED PIPE BACKDRAIN 4" DIAMETER NON-PERFORATED PIPE LATERAL DRAIN SLOPE PER PLAN FILTER MATERIAL BENCHING AN ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY-DIMENSION PER SOILS ENGINEER (GENERALLY 1/2 SLOPE HEIGHT, 15' MINIMUM) DIMENSIONS ARE MINIMUM RECOMMENDED NOT TO SCALE TYPICAL SLOPE STABILIZATION FILL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 18 of 26 4" DIAMETER PERFORATED PIPE BACKDRAIN 4" DIAMETER NON-PERFORATED PIPE LATERAL DRAIN SLOPE PER PLAN FILTER MATERIAL 2%MIN 1 1 ' ........,.._I I I 111 I 11- 1 I ' BENCHING H/2 ~1 ===.. ~. IFF.:,=, ,:rr· 1 "'T""'!, ........ , • ,......,_JI" I · ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR SLOPE IN EXCESS OF 40 FEET HIGH. KEY-DIMENSION PER SOILS ENGINEER DIMENSIONS ARE MINIMUM RECOMMENDED NOTTO SCALE TYPICAL BUTTRESS FILL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 19 of 26 20' MAXIMUM FINAL LIMIT OF EXCAVATION OVEREXCAVATE OVERBURDEN (CREEP-PRONE) DAYLIGHT LINE FINISH PAD OVEREXCAVATE 3' AND REPLACE WITH COMPACTED FILL COMPETENT BEDROCK TYPICAL BENCHING LOCATION OF BACKDRAIN AND OUTLETS PER SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST DURING GRADING. MINIMUM 2% FLOW GRADIENT TO DISCHARGE LOCATION. EQUIPMENT WIDTH (MINIMUM 15') NOTTO SCALE DAYLIGHT SHEAR KEY DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 20 of 26 NATURAL GROUND PROPOSED GRADING ------------------COMPACTED FILL ----------------------------------------------- PROVIDE BACKDRAIN, PER BACKDRAIN DETAIL. AN ADDITIONAL BACKDRAIN AT MID-SLOPE WILL BE REQUIRED FOR BACK SLOPES IN EXCESS OF BASE WIDTH "W" DETERMINED BY SOILS ENGINEER NOTTO SCALE 40 FEET HIGH. LOCATIONS OF BACKDRAINS AND OUTLETS PER SOILS ENGINEER AND/OR ENGINEERING GEOLOGIST DURING GRADING. MINIMUM 2% FLOW GRADIENT TO DISCHARGE LOCATION. TYPICAL SHEAR KEY DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 21 of 26 FINISH SURFACE SLOPE 3 FT3 MINIMUM PER LINEAR FOOT APPROVED FILTER ROCK* CONCRETE COLLAR PLACED NEAT A COMPACTED FILL 2.0% MINIMUM GRADIENT A 4" MINIMUM DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REQUIREMENTS 4" MINIMUM APPROVED PERFORATED PIPE** (PERFORATIONS DOWN) MINIMUM 2% GRADIENT TO OUTLET DURING GRADING TYPICAL BENCH INCLINED TOWARD DRAIN **APPROVED PIPE TYPE: MINIMUM 12" COVER SCHEDULE 40 POLYVINYL CHLORIDE (P.V.C.) OR APPROVED EQUAL. MINIMUM CRUSH STRENGTH 1000 PSI BENCHING DETAIL A-A OMPACTE BACKFILL 12" MINIMUM TEMPORARY FILL LEVEL MINIMUM 4" DIAMETER APPROVED SOLID OUTLET PIPE *FILTER ROCK TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EQUAL: SIEVE SIZE 1" ¾" ¾" N0.4 NO. 30 NO. 50 NO. 200 PERCENTAGE PASSING 100 90-100 40-100 25-40 5-15 0-7 0-3 NOTTO SCALE TYPICAL BACKDRAIN DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 22 of 26 FINISH SURFACE SLOPE MINIMUM 3 FT3 PER LINEAR FOOT OPEN GRADED AGGREGATE* TAPE AND SEAL AT COVER CONCRETE COLLAR PLACED NEAT COMPACTED FILL A 2.0% MINIMUM GRADIENT A MINIMUM 4" DIAMETER SOLID OUTLET PIPE SPACED PER SOIL ENGINEER REQUIREMENTS MINIMUM 12" COVER *NOTE: AGGREGATE TO MEET FOLLOWING SPECIFICATIONS OR APPROVED EQUAL: SIEVE SIZE PERCENTAGE PASSING 1 ½" 100 1" 5-40 ¾" 0-17 ¾" 0-7 NO. 200 0-3 TYPICAL BENCHING DETAIL A-A OMPACTE BACKFILL 12" MINIMUM NOT TO SCALE MIRAFI 140N FABRIC OR APPROVED EQUAL 4" MINIMUM APPROVED PERFORATED PIPE (PERFORATIONS DOWN) MINIMUM 2% GRADIENT TO OUTLET BENCH INCLINED TOWARD DRAIN TEMPORARY FILL LEVEL MINIMUM 4" DIAMETER APPROVED SOLID OUTLET PIPE BACKDRAIN DETAIL (GEOFRABIC) STANDARD SPECIFICATIONS FOR GRADING Page 23 of 26 SOIL SHALL BE PUSHED OVER ROCKS AND FLOODED INTO VOIDS. COMPACT AROUND AND OVER EACH WINDROW. 10' i FILL SLOPE 1 CLEAR ZONE __/ EQUIPMENT WIDTH STACK BOULDERS END TO END. DO NOT PILE UPON EACH OTHER. 0 0 0 0 ~ 10' MIN O NOT TO SCALE 0 ROCK DISPOSAL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 24 of 26 STAGGER ROWS FINISHED GRADE BUILDING 10' SLOPE FACE 0 NO OVERSIZE, AREA FOR FOUNDATION, UTILITIE~~l AND SWIMMING POOL:_i_ 0 0 STREET 1--d 4•L-. WINDROW~ 0 5' MINIMUM OR BELOW DEPTH OF DEEPEST UTILITY TRENCH (WHICHEVER GREATER) TYPICAL WINDROW DETAIL (EDGE VIEW) GRANULAR SOIL FLOODED TO FILL VOIDS HORIZONTALLY PLACED COMPACTION FILL PROFILE VIEW NOT TO SCALE ROCK DISPOSAL DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 25 of 26 GENERAL GRADING RECOMMENDATIONS CUTLOT ------------ ------, --UNWEATHERED BEDROCK OVEREXCAVATE AND REGRADE COMPACTED FILL ~ -----TOPSOIL, COLLUVIUM ,--AND WEATHERED ., BEDROCK ,,.- ----,,.- CUT/FILL LOT (TRANSITION) ~ ~ ---- UNWEATHERED BEDROCK NOT TO SCALE TRANSITION LOT DETAIL STANDARD SPECIFICATIONS FOR GRADING Page 26 of 26 _.......-:: ORIGINAL ,,. ,,. ,,. ,,. , GROUND 'MIN 3'MIN OVEREXCAVATE AND REGRADE APPENDIX E SITE INSPECTION REPORT BY SOIL TESTERS 2005 111111, TRITEU :fl ______________ _ P.O. Box 1195 September 2, 2005 Lakeside, California 92040 (619) 443-0060 MikeO,Gara P. 0. Box 1633 Carlsbad, California 92018 Subject: File No. 1106F3-05 SITE INSPECTION Proposed Residential Building Site 3980 Highland Avenue City of Carlsbad Dear Mr. O'Gara: SCOPE In accordance with your request, a Site Inspection has been performed at the subject sit.e. The purpose of this investigation was to examine existing site conditions and provide engineering recommendations for the five, proposed two-story over basement, single-family residential structures. FIELD INSPECTION In order to accomplish this purpose, a representative of this firm visited the site, reviewed the topography and site conditions and visually and textually classified the surface and near surface soils. Representative samples of the on-site soils were obtained from three test explorations approximately four to fifteen feet in depth and tested for density, shear strength and expansive characteristics. SITE CONDIDONS The suiject site is a residential parcel located on the easterly side of Highland Drive. The property is located at the top of a rise with the east side of the property fronting James Drive approximately 15 to 20 feet lower than the west side. A IO-foot, 2: 1 cut slope extends midway through the site from the south to north. A 2 to 3 feet fill slope is located at the top of the cut on the north end. The property is presently occupied by a one-story single-family residence with detached garage. There is a four-foot retaining wall behind the garage and a 3-foot rock retaining wall behind the house. Adjacent properties are occupied by residential structures. 1 :MikeO'Gara File No. l 106F3-05 September 2, 2005 Man-made fill soils were encountered to a depth of approximately one to three feet during the course of this inspection; however, native soils were loose and compress1l>le to approximately 15 feet in depth. son, CONDfflONS Soils encountered in Test Exploration No. 3 at the higher elevation off Highland Drive were generally firm to medium dense, cemented, red brown silty sands becoming more dense with depth to the bottom of the excavation, approximately four feet in depth. Test Explorations Nos. 1 and 2 were located below the cut at the lower elevation off James Drive. Soils encountered in these explorations were generally loose to firm granular sands to l O to 15 feet in depth. Dense formational soils were not encountered at the lower elevation. None of the soils we encountered were considered to be detrimentally expansive with respect to change in volume with change in moisture content. CONCLUSIONS AND RECOMMENDATIONS 1. The loose native soils we encountered at the lower elevations should not be utilized to support the proposed new structures. In order to provide adequate support, the loose soils should be removed to at least five feet below the lowest footing and the bottom of the excavation compacted using a vibratory compacter. The bottom of the excavation should be tested to insure that compaction is at least 90 percent of maximum dry density. The soils may then be replaced and recompacted to at least 90 percent of maximum dry density in accordance with the Grading Specifications in this report. The recompaction should extend at least 5 feet outside the proposed building footprint. An.y deleterious material that may be encountered should be removed prior to recompaction. · 2. We anticipate that basement excavations for the structures located in the higher elevations will achieve suitable soils for adequate support. The basement excavations should be inspected by a representative of this firm to insure that proper soil strata have been achieved. 3. No special foundation design to resist expansive soil is necessary. Conventional spread footings founded a minimum of 12 inches below lowest adjacent grade and having a width determined by the allowable soil bearing value as detailed above may be used for foundation support. Footing widths should be at least 12 inches for continuous footings and 24 inches for square footings due to practical considerations as well as Building Code requirements. These recommendations are based upon the soil type only and do not take into consideration structural requirements. 2 MlkeO'Gara File No. I 106F3-05 September 2, 2005 4. Reinforcing in footings should consist of at least one #4 steel bar placed continuously in the top and bottom of continuous footings regardless of structural requirements. Reinforcing for isolated footings are dictated by the structural requirements. These recommendations are based upon the soil type encountered and do not take into consideration the proposed bearing load. 5. Concrete slabs-on-grade should be constructed to have a nominal thickness of 4!1 and underlain with a sand blanket of 3 inches in thickness. Provide minimum temperature reinforcement consisting of 6X6-l0/10 welded wire mesh. The sand subbase (sand blanket) should have a sand equivalent exceeding 30 per ASTM D2419. All slabs should either have a conventional thickened edge or be poured monolithically with continuous footings at the slabs perimeter. Conventional thickened edges should be 8" thick at slab edge, unifonnly tapering to 4" thick at 2' from slab edge. The thickened edges or monolithic footings should extend completely around the slab's perimeter. Construction and expansion joints should be considered slab edges. Maximum spacing of expansion joints is 50' for interior slabs and 30' for exterior slabs. 6. A representative sample of the foundation soil was remolded to 90% of maximum dry density. Based on the following test results, a safe allowable bearing value of at least 2500 pounds per square foot for 12 inch deep footings may be used in designing the foundations and slab for the proposed structures. This value may be increased by one third for wind and/or seismic loading. Soil Description Depth of Sample Angle of internal friction Cohesion Unit weight Maximum Dry Density Optimum Moisture Content Expansion Index Red brown silty sand 3' 39° 243 psf 121.0 pcf 133.4 pcf 8.5% 31 7. Resistance to horizontal movement may be provided by allowable soil passive pressure and/or coefficient of fiiction of concrete to soil. The allowable passive pressure may be assumed to be 500 psf at the surface and increasing at the rate of 500 psf per foot of depth. These pressures assume a fiictionless vertical element, no surcharge and level adjacent grade. If these assumptions are incorrect, we should be contacted for values that reflect the true conditions. The values are for static conditions and may be increased 1/3 for wind and/or seismic loading. The coefficient of friction of concrete to soil may be safely assumed to be O .5. 3 :MikeO'Gara File No. 1106F3-05 September 2, 2005 8. Active pressures for the design of unrestrained, cantilevered, individually supported retaining walls capable of slight movement away from load may be considered to be equivalent to the pressures developed by a fluid with a density of30 pcf This value assumes a vertical, smooth wall and level drained backfill. We should be contacted for new pressures if these assumptions are incorrect. Restrained walls, incapable of movement away from load without damage such as basement walls, should be designed for the additional equivalent fluid of 24 pcf applied triangularly for cohesionless type soils and trapezoidally for cohesive type soils. The above design values and foundation design assume that the basement wall excavations will expose soils similar to those we tested during our site inspection. We should inspect the cut to insure that the soils exposed are the same as those we tested. For any grading proposed or. contemplated for this project, the following grading specifications should be utilized. RECOMMENDED GRADING SPECIFICATIONS Proposed Residential Building Site 3980 Highland Avenue City of Carlsbad GENERAL: Soil Testers and 'Soil Engineer' are synonymous hereinafter and shall be employed to inspect and test earthwork in accordance with these specifications, the accepted plans, and the requirements of any jurisdictive governmental agencies. They are to be allowed adequate access so that the inspections and tests may be performed. The Soil Engineer shall be apprised of schedules and any unforeseen soil conditions. Substandard conditions or workmanship, inadequate compaction, adverse weather, or deviation from the lines and grades shown on the plans, etc., shall be cause for the soil engineer to either stop construction until the conditions are corrected or recommend rejection of the work. Refusal to comply with these specifications or the recommendations and/or interpretations of the soil engineer will be cause for the soil engineer and/or his representative to immediately tenninate his services. Deviations from the recommendations of the Soil Report, from the plans, or from these Specifications must be approved in writing by the owner and the contractor and endorsed by the soil engineer. 4 MikeO'Gara SOIL TEST METHODS: Maximum Density & Opt Moisture Density of Soil In-Place Soil Expansion Shear Strength Gradation & Grain Size File No. l 106F3-05 September 2, 2005 -AS1MD1557-70 --AS1M Dl556, D2922 and D3017 -UBC STANDARD 29-2 --AS1M D3080-72 -AS1M Dl 140-71 --AS1M D2325-68 Capillary Moisture Tension Organic Content -% Weight loss after heating for 24 hours at 300° F and after deducting soil moisture. LIMITING SOIL CONDIDONS: Minimum Compaction 900/o for 'disturbed' soils. (Existing fill, newly placed fill, plowed ground, etc.) 84% for natural, undisturbed soils. Expansive Soils Insufficient fines Oversized Particles 95% for pavement subgrade within 2' of finish grade and pavement base course. Expansion index exceeding 20 Less than 40% passing the #4 sieve. Rocks over 1 O" in diameter. PREPARATION OF AREAS TO RECEIVE FILL: Brush, trash, debris and detrimental soils shall be cleared from the areas to receive fill. Detrimental soils shall be removed to firm competent soil. Slopes exceeding 20% should be stepped uphill with benches 1 0' or greater in width. Scarify area to receive fill to 6n depth and compact. FllL MATERIAL shall not contain insufficient fines, oversized particles, or excessive organics. On-site disposition of oversized rock or expansive soils is to be at the written direction of the Soil Engineer. Select fill shall be as specified by the soil engineer. Alt 611s shall be campacte.d and tested SUBDRAJNS shall be installed if required by and as directed by and detailed by the soil engineer and shall be left operable and unobstructed. They shall consist of 3" plastic perforated pipe set in a minimum cover of 4" of filter rock in a 'vee' ditch to intercept and drain free ground from the mass fills. Perforated pipe shall be schedule 40, Poly-Vmyl-Chloride or Acrylonitrile Butadienne Styrene plastic. Rock filter material shall conform to the following gradation: Sieve size: %Passing: 3/411 90-100 #4 25-50 ,5 #30 5-20 #200 0-7 MikeO'Gara File No. 1106F3-05 September 2, 2005 Subdrains shall be set at a minimum gradient of0.2% to drain by gravity and shall be tested by dye flushing before acceptance. Drains found inoperable shall be excavated and replaced. CAPPING EXPANSIVE SOILS: If capping expansive soils with non-expansive soil to mitigate the expansive potential is used, the cap should be compacted, non-expansive, select soil placed for a minimum thickness 3' over the expansive soil and for a minimum distance of 8' beyond the exterior perimeter of the structure. Special precautions should be taken to ensure that the non-expansive soil remains uncontaminated and the minimum thickness and dimensions around the structure are maintained. The expansive soils underlying the cap of non-expansive cap should be pre-saturated to a depth of3' to obtain a degree saturation exceeding 90% before any construction supported by the compacted cap. The non-expansive soil comprising the cap should conform to the following: Minimum Compaction Maximum Expansion Index Minimum Angle of Internal Friction Cohesion Intercept 90% 30 33Deg IO0psf UNFORESEEN CONDfilONS: Soil Testers assume no responsibility for conditions, which differ from those, described in the applicable current reports and documents for this property. Upon termination of the soil engineer's services for any reason, his fees up to the time of termination become due and payable. If it is necessary for the soil engineer to issue an unfavorable report concerning the work that he has been hired to test and inspect, the soil engineer shall not be held liable for any damages that might result from his 'unfavorable report'. If we can be of any further assistance, please do not hesitate to contact our office. This opportunity to be of service is sincerely appreciated. Respectfully submitted, 6 [;ii T-2. i:. -r-3 LOCATION OF EXPLORATION TRENCHES ~ EXPLORATION TRENCH 11421 Woodside Ave., Suite C Santee, California 92071 ( 619) 562-0500 L--------------'-------------'------- Mike O'Gara Plate No. 2 EXPLORATION NUMBER l Date Logged: Date Reported: 6/28/05 9/02/05 D h U "fi dCl ept Ill le "fi asst 1cat10ns 0to6' SM Red brown, 6 to 15' SM Red brown, File No. 1106F3-05 September 2, 2005 S ·10 01 humid, loose, humid, firm, Equipment Used: Groundwater: Refusal: escnpt10n Backhoe Not Encountered Not Encountered s ii o Type SIL TY SAND with clay binder 1 (Native) SJL TY SAND with clay binder l (Native) Darker brown, wet, firm, SIL TY SAND Limit of Equipment MikeO'Gara Plate No. 3 EXPLORATION NUMBER 2 Date Logged: Date Reported: 6/28/05 9/02/05 h "ti d l "ti Dept Um 1e C ass1 1cat10ns 0 to 10' SM Red brown, SILTY SAND IO to 11' SM Tan moist, File No. 1106F3-05 Equipment Used: Groundwater: Refusal: S ·10 01 escnot10n moist, firm to medium dense, loose, cemented, granular, Bottom of trench September 2, 2005 Backhoe Not Encountered Not Encountered S ·1 01 Type cemented, I (Native) SILTY SAND (Native) MikeO'Gara Plate No. 4 EXPLORATION NUMBER 3 Date Logged: Date Reported: D h U ·ri d Cl ept ru 1e 0to4' SM 6/28/05 9/02/05 ifi ass 1cat10ns Red brown, File No. l l06F3-05 Equipment Used: Groundwater: Refusal: S ·10 f 01 escnp 10n September 2, 2005 Backhoe Not Encountered Not Encountered S ·1 T 01 ype humid, medium dense, SILTY SAND I (Native) bottom of trench SOIL TEST RESULTS ON REMOLDED SAMPLES .------REMOLDED SPECIMENS-----, Soil Type rlassification Sample Tested I I General Description V V V V Id Clsf v Color Texture 1 SM T1@3' Red brown SIL TY SAND Maximum! Density (pcf) Optimum Moistur I S'iiflC V V V Yrnx OMc Gs 133.4 8.5 2.65 Density (pcf) J Compaction Friction (deg) ravity I Moisture I Cohesion (psf) Expansio lnde>4 I Saturation I V V V V V V V El Yd Re We Ds Fr c 20 121.4 91% 6.4% 75% 39 243