Loading...
HomeMy WebLinkAboutSDP 2018-0011; GOMEZ RENOVATION; REPORT OF LIMITED GEOTECHNICAL INVESTIGATION; 2019-03-11to f Y it r --- ------- SOil and Foundation Engineers REPORT OF LIMITED GEOTECHNICAL INVESTIGATION Proposed Single-family Residence 315.9B Madison Street Carlsbad, CA JOB NO. 197113 March 11, 2019 Prepared for: Darren Machuisky 3508 Woodland Way Carlsbad, CA. 92008 RECEWED APR 22 2319 LAND DEVELOPMENT ENGINEERING .7840 EL CAJON BLVD., SUITE 200 • LA MESA, CALIFORNIA 91942 Phone: (619) 462-9861 • Email: Clamonte@Flash.Net • Fax: (619) 462-9859 F] ca" W11a' La Nkmk cwnpary Int Soil and Foundation Engineers - Ti 1 7840 EL CAJON BLVD., SUITE 200 • LA MESA, CALIFORNIA 91942 Phone: (619) 462-9861 • Email: ClamonteFlash.Net • Fax: (619) 462-9859 March ll,2019 job No. 197113 TO: Darren Machuisky 3508 Woodland Way Carlsbad, CA. 92008 SUBJECT: Report of Limited Geotechnical Investigation Proposed Single-family Residence 3159B Madison Street Carlsbad, CA In accordance with your request, we have performed a geotechnical investigation for the proposed residential development. We are presenting herein our findings and recommendations. The above referenced geotechnical investigation, conducted in 1998, and included the subject-property as well as the adjacent parcels to the east and west. The findings of this investigation have been incorporated into this report as well as the findings of our independent site exploration. In general, we found the property suitable for the proposed project provided that the recommendations contained herein are adhered to. We found the proposed project site to be overlain with up to 4 feet of loose fill and topsoil. The property is underlain at depth with competent sedimentary bedrock. Much of the loose surficial soils will be removed by future cut and export operations. Remaining loose surface soils may require mitigation by remedial grading in some locations. Detailed earthwork and foundation recommendations are provided in the ensuing report. If you should have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to he of professional service is sincerely appreciated. Respectfully submitted, Exp. eo Jerry Re No. 25241 No. 495 . 1io19% CliffoV. La Monte, R.C.E. 2524-1G .E. 0495 C 0 TABLE OF CONTENTS PROJECT DESCRIPTION . 1 • SCOPE OF WORK ...........................................................................................................1 FINDINGS..................................................... . ..................................................................... 3 SITE DESCRIPTION ................ ........................................................................................ 3 DESCRIPTION OF SUBSURFACE SOIL CONDITIONS. ........................................... 3 GROUNDWATER ...........................................................................................................4 • SEISMICITY AND FAULTING ........................................................................................ 5 SEISMIC DESIGN PARAMETERS ................................................................................ .6 GEOLOGIC HAZARDS ........................... .............................. . ........................................ 7 CONCLUSIONS................................................................................... . ............................ 8 RECOMMENDATIONS.......................................................... ..........................................9 EARTH WORK AND GRADING .................................................................................... 9 Specifications and Preconstruction ............... ............................................................ 9. Compaction and Method of Filling ..........................................................................10 TemporaryCut Slopes ............................................................................................... 11 Excavation Characteristics ...................................................................................... 11 Excavation Characteristics......................................................................................11 SurfaceDrainage .......................................................................................................11 ErosionControl ........................................................................................................ 12 Grading Plans Review ................... . ......................................................................... 12 • FOUNDATIONS .......... .....................................................................................................12 General......................................................................................................................12 Foundation Embedment .......................................................................................... 12 SoilBearing Value ................................................................................................... 13 Lateral Load Resistance..........................................................................................13 • Foundation Reinforcement ...................................... .............................................. 13 Anticipated Settlements .........................................................................................14 Foundation Excavation Observation .......................... .14 Foundation Plan Review ...................................... .................................................. 14 Horizontal Distance of Footings from Slopes ....................................................14 • CONCRETE SLABS-ON-GRADE .............................. .................................................. 14 SLAB MOISTURE BARRIERS . ..................................................................................... 15 Interior Slab Curing Time ......................................................................................16 DESIGN PARAMETERS FOR EARTH RETAINING STRUCTURES....................16 Passive Pressure ......................................................................................................16 • Soil Bearing Value...................................................................................................17 Active Pressure for Retaining Walls ..................................................................... 17 Retaining Wall Foundations .................................................................... .............. 17 Waterproofing and Subdrain Observation..........................................................17 Backfill........................................................................................................................ 18 FIELD INVESTIGATION.................................................................................................18 LABORATORY TESTS AND SOIL INFORMATION ................................................ 19 LIMITATIONS................................................................................................................. 19 TABLES Table I Mapped Spectral Acceleration Values and Design Page 6 Table II Foundation Embedment Page 13 Table III Equivalent fluid weights Page 17 L) ATTACHMENTS FIGURES Figure No. 1 Figure No. 2A Figure No. 2B Figure No.3 A and 3B Figure No. 4 Figure No. 5 Site Location Map (Tope.) Plot Plan and Geotecimical Map Site Plan -Proposed Development Test Boring Logs Regional Geologic Map Excerpt (2005) Regional Fault Activity Map ri APPENDICES Appendix "A"- Standard Grading Specifications Appendix "B" - Unified Soil Classification Chart 0 Proposed Residence March Ii, 2019 3159B Madison St. Carlsbad, CA Page 2 REPORT OF LIMITED GEOTECHNICAL INVESTIGATION . Proposed Single-family Residence. 3159 B Madison Street Carlsbad, CA PROJECT DESCRIPTION The following report presents the results of a limited geotechnical investigation performed for the proposed residential project. The project site is a developed residential lot located at 3159B Madison Street in the City of Carlsbad, California. . Figure Number 1 (attached) provides a vicinity map showing the approximate location of the property and area topography. The project site is currently improved a one-story single-family residence. We understand the existing residence will be removed to make way for a new 2-story single-family residence. The existing residence at 3159A Madison Street will remain. The existing shed will be relocated to a central portion of the lot. The proposed structure will be a founded on conventional shallow foundations with slab-on-grade floors. The structure will be constructed at or near the grade of the existing home so ,planned grading is anticipated to be minor. This report has been prepared for the exclusive use of the stated client and his design consultants for specific application to the project described herein. Should the project be changed in any way, the modified plans should be submitted to C. W. La Monte Company, Inc. for review to determine their conformance with our recommendations and to determine if any additional subsurface investigation, laboratory testing and/or recommendations are necessary. Our professional services have been performed, our findings obtained and our recommendations prepared in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties, expressed or implied. CA SCOPE OF WORK The scope of this investigation was limited to: surface reconnaissance, research of readily available geotechnical literature pertinent to the site, subsurface exploration, laboratory testing, engineering and geologic analysis of the field and laboratory data and preparation of this report. More specifically, the intent of this investigation was to: Review available geotechni:al reports and maps pertinent to the subject site. S Identify the subsurface conditions of the site to the depths influenced by the proposed construction. Based on laboratory testing and our experience with similar sites in the area, identify the engineering properties of the various strata that may influence the proposed construction, including the allowable soil bearing pressures, expansive characteristics and settlement potential. Describe possible geotechrrical factors that could have an effect on the site development. Provide mapped spectral acceleration parameters from USGS Seismic Design Maps. Address potential construction difficulties that may be encountered due to soil conditions and groundwater, and provide recommendations concerning these problems. • Recommend an appropriate foundation system for the proposed structure and develop soil engineering design criteria for the recommended foundation designs. Present our opinions in this written report, which includes in addition to our findings and recommendations, a site plan showing the location of our subsurface explorations, logs of the test trenches and a summary of our laboratory test results. It was not within our scope Df work to evaluate the site for hazardous materials contamination. Further, we did not perform laboratory tests to evaluate the chemical characteristics of the on-site soils in regard to their potentially corrosive impact to on- grade concrete and below grade improvements. The soil bearing conditions of the existing home, to remain, were not evaluated. Proposed Residence March 11, 2019 Page 2 3159B Madison St. Carlsbad, CA FINDINGS S SITE DESCRIPTION The property is located 3159 Madison Street in the City of Carlsbad, California. The lot alignment is skewed in a northeast-southwest alignment; to simplify discussions north is assumed to be oriented towards the northwest in alignment with Madison Street. Using this convention the property is bounded on the north and south with single-family homes, on the west with an alley, and on the east with Madison Street. A legal description of the property is Assessor's Parcel Number 204-084-05-00. The property is rectangular-shaped and is approximately 25 feet wide and a 140 feet deep. The lot is improved with two, one-story single-family homes. A residence at 3159A occupies the eastern portion of the lot and fronts on Madison Street. The subject 3159B residence occupies the western portion of the lot and fronts on the alley. A shed is located between the structures. A privacy fence separates the two homes. Topographically, the property is relatively level and appears to drain by sheet flow S to the alley and street. Survey information concerning actual elevations was not available at the time of our investigation. However, a review of area topographic maps indicates elevations on the order of 50 feet MSL. DESCRIPTION OF SUBSURFACE SOIL CONDITIONS The site is located within the coastal plain section of the Peninsular Ranges Geomorphic Province of California. The coastal plain generally consists of subdued landforms underlain by tertiary to quaternary aged marine sedimentary deposits. The site was found to be underlain Quaternary aged sedimentary formational deposits with associated surficial materials and minor fills. These soil types are described individually below in order of increasing age. Also refer the attached Test Boring Logs, Figure No. 3A&3B. A Plot Plan and Geotechnical Map is attached as. Figure No. 2A with the test boring locations a mapping of the encountered units. An 5 excerpt from a regional geologic map is included as Figure No. 4. Fill: Localized fills soils were encountered in Test Boring B-3. The fills were about 2.5 feet and consist of dark brown, loose to medium dense, silty sand Proposed Residence March 11, .2019 Page 3 3159B Madison St. Carlsbad, CA S S with a little solid trash debris. Topsoil: The site is capped with about 3 feet of topsoil materials. The topsoil consists primarily of dark reddish brown, loose to medium dense, silty sand (SM). The topsoils are moderately compressible and require remedial grading. Based on our visual and textural classification plus our past experience with similar soils in the vicinity of the subject site, these materials are anticipated to possess a "very low" expansion potential. Old Paralic Deposits (Qop): According to the Di gital Geologic Map of the Oceanside 30' X 60' Quadrangle, Southern California (2005), by Kenned5i Tan (Kenned and Tan, 2005), the site is underlain at depth with competent and Quaternary-aged old paralic deposits. The encountered formational materials consist primarily of reddish brown to light brown, silty sands Based on our visual and textural classification plus our past experience with similar soils in the vicinity of the subject site, the above materials are anticipated to possess a "very low" expansion potential. GROUND WATER No groundwater was encountered in our test excavations at the time of our investigation, which extended to a maximum depth of 8 feet. Based on our past experience and area reconnaissance, groundwater is anticipated at depths greater than 20 feet. It should be kept in mind, that any required grading operations might change surface drainage patterns and/or reduce permeability due to the densification of compacted soils. Such changes of surface and subsurface hydrologic conditions, plus irrigation of landscaping or significant increases in rainfall, may result in the appearance of surface or near-surface water at locations where none existed previously. The damage from such water is expected to be minor and cosmetic in nature, only if good positive drainage is implemented at the completion of construction. Corrective action should be taken on a site-specific basis if, and when, it becomes necessary. Proposed Residence March 11, 2019 Page 4 3159B Madison St. Carlsbad, CA 41 SEISMICITY AND FAULTING I No faults are known to traverse the site, thus it is not considered susceptible to surface rupture as a result of on-site faulting. The probability of soil cracking caused by shaking from close or distant fault sources is also considered to be low. It should be noted that much of Southern California, including the San Diego County area is characterized by a series of Quaternary-age fault zones, which typically consist of several individual, en echelon faults that generally strike in a northerly to north- westerly direction. Some of these fault zones (and the individual faults within the zones) are classified as active while others are classified as only potentially active, according to the criteria of the California Division of Mines and Geology (currently California Geological Survey). Active fault zones are those that have shown conclusive evidence of faulting during the Holocene Epoch (the most recent 11,000 years), while potentially active fault zones have demonstrated movement during the Pleistocene Epoch (11,000 to 2 million years before the present) but no movement during Holocene time. An excerpt from the 2010 Fault Activity Map of California (California Geological Survey) is attached as Figure No. 5 and provides the recency of faulting in the site vicinity. Current geologic literature indicates that the Rose Canyon / Newport-Englewood Fault Zone is the nearest active fault with the nearest segment mapped offshore about 2 miles west of the site. According to the 2008 National Seismic Hazard Maps - Fault Parameters (USGS website), the Maximum Magnitude earthquake on the Rose Canyon / Newport-Inglewood Fault Zone is 6.9 (Ellsworth) or 6.7 (Hanks) with a slip rate of 1.5. The Rose Canyon Fault Zone is currently classified as a Type "B" fault (California Probabilistic Seismic Hazard Maps, June 2003. O Other nearby faults, as shown on Figure Number 5, includes several unnamed Pre- Quaternary (inactive) faults located within 5 miles of the site and located to the north, south and east. Also the La Nacion Fault Zone and other Quaternary faults are located over 25 miles south of the property. These faults are considered potentially active, inactive, presumed inactive, or activity unknown, by the City of San Diego Seismic Safety Study [potentially active faults have demonstrated movement during the Pleistocene Epoch (11,000 to 1.6 million years before the present) but no movement during Holocene (recent) times]. The Elsinore and San Jacinto Fault Zones located about 37 and 57 miles (respectively) northeast of the site. The City of San Diego Seismic Safety Element estimates the maximum probable earthquake for both the San Jacinto and the Elsinore fault zones is between M 6.9 and 7.3, with a repeat interval of approximately 100 years. The maximum credible earthquake for both fault zones is estimated at M 7.6. • Proposed Residence March 11, 2019 Page 5 3159B Madison St. Carlsbad, CA 41 Other active fault zones in the region that could possibly affect the site include the Coronado Bank and San Clemente Fault Zones to the southwest, and the Earthquake Valley Fault and San Andreas Fault Zones to the northeast. However, a Maximum Magnitude Earthquake on the Rose Canyon or Elsinore Fault Zones is anticipated to generate ground accelerations on the site, greater than any of the other nearby fault According to the Official Map of Aiquist-Priolo Earthquake Fault Zones of California, by the California Division of Mines and Geology (currently. California Geological Survey) (CDMG, 1991) the site IS NOT located an Alquist-Priolo Earthquake Fault Zone map. SEISMIC DESIGN PARAMETERS We have re-determined the mapped spectral acceleration values for the site utilizing current U.S. Seismic Design Maps from the USGS website. The analysis included the following input parameters: Design Code Reference Document: ASCE7- 16 Standard Site Soil Classification: Site Class D Risk Category: II Site Coordinates: 33.15910°N, 117.34585°W The values generated by the Design Map Report are provided in the following table: TABLE I Site Coefficients and Spectral Response Acceleration Parameters Ss S1 Fa F Sms Smi Sd Sd1 PGA 1.077 0.389 1.069 null 1.151 null 0.768 null 0.475 Application to the criteria in Table I for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if ever seismic shaking-occurs. The primary goal of seismic design is to protect life, not to avoid all damage, since such design may be economically prohibitive. 0 Proposed Residence March 11, 2019 Page 6 3159B Madison St. Carlsbad, CA 0 . GEOLOGIC HAZARDS 7 General: No geologic hazards of sufficient magnitude to preclude development of the site as currently proposed are known to exist. In our professional opinion and to the best of our knowledge, the site is suitable for the proposed development. Ground Shaking: A likely geologic hazard to affect the site is ground shaking resulting from movement along one of the major active fault zones mentioned above. Probable ground shaking levels at the site could range from slight to severe, depending on such factors as the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience the effects of at least one moderate to large earthquake during the life of the proposed structures. Construction in accordance with the minimum requirements of the current building codes and local governing agencies should minimize potential damage due to seismic activity. Landslide Potential and Slope Stability: A detailed, deterministic slope stability analysis was not included within our scope of services. However, as part of this investigation we reviewed the publication, "Landslide Hazards in the Southern Part of the San Diego Metropolitan Area" by Tan and Giffen, 1995. This reference is a comprehensive study that classifies San Diego County into areas of relative landslide susceptibility. The subject site is located in Area 3. The 3 classification is typically assigned to areas generally susceptible to slope movement. The site is further located in Subarea 3-1 within the 3 classification. Slopes within the 3-1 subarea generally occupy steeper and higher slopes which are marginally stable and potentially susceptible to landslides and other slope failures. Due to the sites underlying stable bedrock and gentle topography, deep-seating landsliding does not appear to present a significant geotechnical hazard. Liquefaction: The materials at the site are not subject to significant liquefaction due to such factors as soil density, grain-size distribution, and groundwater conditions. Soil Expansion: Generally, the soils encountered at the site are considered to possess a very low-expansive potential. Flooding: The site is located outside the boundaries of both the 100-year and the 500-year floodplains according to the maps prepared by the Federal Emergency Management Agency. Proposed Residence March 11, 2019 Page 7 3159B Madison St. Carlsbad, CA 9 Tsunamis and Seiches: Tsunamis are great sea waves produced by submarine earthquakes or volcanic eruptions. Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs. Based on the project's elevated location, the site is considered to possess a low risk potential from tsunamis, or seiche activity. I CONCLUSIONS I In general, our findings indicate that the project site is suitable for the proposed structures, provided the recommendations presented herein are followed. The most significant geotechnical conditions that will influence site development are summarized below. The lot is overlain with about 3 to 4 feet of potentially compressible topsoils and localized fills. Therefore, an "undercut" grading operation is recommended to mitigate this condition. The loose surficial materials should be removed down to competent material and be replaced back in the excavation as compacted fill (as needed to achieve design elevations). Where possible the removals should extend at least 4 feet beyond the perimeter of the structure. No groundwater was encountered in our test explorations that extended to a maximum depth of approximately 8 feet below the existing grade. Therefore, groundwater should not present issues to the proposed development. • The foundation level materials encountered at the site are considered to possess a very low to low expansion potential (expansion index [El] less than 50) as defined by ASTM 4829. Recommendations for heaving soils are not required. We do not anticipate a significant transition (cut/fill) we be generated by the recommended site grading. FJ Proposed Residence March 11, 2019 Page 8 3159B Madison St. Carlsbad, CA 0 RECOMMENDATIONS 1 EARTH WORK AND GRADING Specifications and Preconstruction All grading should conform to the guidelines presented in this report, Sections 1804 and Appendix "J" of the 2016 California Building Code, the minimum requirements of the City of Carlsbad and the Recommended Grading Specifications and Special Provisions (Appendix A) attached hereto, except where specifically superseded in the text of this report. Prior to grading, a representative of C.W. La Monte Company Inc. should be present at the preconstruction meeting to provide additional grading guidelines, if necessary, and to review the earthwork schedule. Fill Suitability On-site excavated materials may be used as compacted fill material or backfill. The on-site materials, typically, possess a very low expansion potential. Any potential import soil sites should be evaluated and approved by the Geotechnical Consultant prior to importation. At least two working days notice of a potential import source should, be given to the Geotechnical Consultant so that appropriate testing can be accomplished. The type of material considered most desirable for import is a non- detrimentally expansive granular material with some silt or clay binder. Observation of Grading Observation and testing by the soil engineer is essential during the grading operations. This observation car range from continuous to an as-needed basis, based on the project situation. This allows the soil engineer to confirm the conditions anticipated by our investigation, to allow adjustments in design criteria to reflect the actual field conditions exposed, and to determine that the grading progresses in general accordance with the recommendations contained herein. Site Preparation Site preparation should begin with the removal of the all improvements designated for removal and all vegetation and other deleterious materials from the portion of the lot that will be graded and/or that will receive improvements. This should include all root balls from the trees removed and all significant root material. The resulting materials should be disposed of off-site. Proposed Residence , March 11, 2019 Page 9 3159B Madison St. Carlsbad, CA After clearing and grubbing, site preparation should continue with the removal all existing topsoil material from areas that will be graded or that will support settlement-sensitive improvements. Topsoil removals are expected to be about 3 feet, but may be thicker in localized areas. Where possible, the removals should extend laterally a minimum of 4 feet beyond the structure perimeter or to a distance equal to the depth of removals (whichever is greater). All removal areas should be approved by a representative of our office prior to the placement of additional fill or improvements. In areas where lateral removals are limited, due to property line constraints, deepened foundations may be used to compensate for deficiencies in lateral removal of unsuitable soils. Prior to placing any fill soils or constructing any new improvements in areas that have been cleaned out to receive fill, the exposed soils should be scarified to a depth of approximately 6 to 12 inches, be moisture conditioned, and compacted to at least 90 percent relative compaction. Compaction and Method of Filling 40 All structural fill placed at the site and should be compacted to a minimum relative compaction of at least 90 percent of its maximum dry density as determined by ASTM Laboratory Test D1557. Any backfill soils supporting first story areas that overhang the basement shall be compacted to at least 95 percent. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick, with each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by our soil technicians or project geologist. All material should be free of rocks or lumps of soil in excess of twelve inches in maximum width. However, in the upper two feet of pad grade, no rocks or lumps of soil in excess of six inches should be allowed. Utility trench backfill within five feet of the proposed structure and beneath all pavements and concrete flatwork should be compacted to a minimum of 90 percent of its maximum dry density. The upper one-foot of pavement subgrade and base material should be compacted to at least 95 percent relative density. All grading and fill placement should be performed in accordance with the local Grading Ordinance, the California Building Code, and the Recommended Grading Specifications and Special Provisions attached hereto as Appendix A. . Proposed Residence March 11, 2019 Page 10 3159B Madison St. Carlsbad, CA 40 Temporary Cut Slopes We anticipate no temporary cut slopes exceeding 4 feet in height and, therefore, specifications for temporary cuts are not provided at this time. It should be noted that the contractor is solely responsible for designing and constructing stable, temporary excavations and may need to shore, slope, or bench the sides of trench excavations as required to maintain the stability of the excavation sides where friable sands or loose soils are exposed. The contractor's "responsible person", as defined in the OSHA Construction Standards for Excavations, 29 CFR, Part 1926, should evaluate the soil exposed in the excavations as part of the contractor's safety process. In no case should slope height, slope inclination, or excavation depth, including utility trench excavation depth, exceed those specified in local, state, and federal safety regulations. Actual safe slope angles should be verified by the geotechnical consultant at the time of excavation. Excavation Characteristics Based on our exploratory excavations, the subsurface materials at the site appear relatively easy to moderate to excavate with conventional earthmoving equipment and will generate good quality silty sand to poorly graded sand material. No significant amounts of oversize rock material are anticipated. Excavation Characteristics Based on our exploratory excavations, the subsurface materials at the site appear relatively easy to moderate to excavate with conventional earthmoving equipment and will generate good quality silty sand. No significant amounts of oversize rock material are anticipated. Surface Drainage Surface runoff into graded areas should be minimized. Where possible, drainage should be directed to suitable disposal areas via non-erodible devices such as paved swalés, gunited brow ditches, and storm drains. Pad drainage should be designed to collect and direct surface water away from proposed structures and toward approved drainage areas and/or LID systems. Section 1804.3 of the California Building Code specifies the following for site grading: The ground immediately adjacent to the foundation shall be sloped away from the building at a slope of not less than one unit vertical in 20 units horizontal (5-percent slope) for a minimum distance of 10 feet measured perpendicular to the face of the wall. If physical obstructions or lot lines prohibit 10 feet of Proposed Residence March 11, 2019 Page 11 3159B Madison St. Carlsbad, CA horizontal distance, a 5-percent slope shall be provided to an approved alternative method of diverting water away from the foundation. Swales used for this purpose shall be sloped a minimum of 2 percent where located within 10 feet of the building foundation. Impervious surfaces within 10 feet of the building foundation shall be sloped at a minimum of 2 percent away from the building... The procedure used to establish the final ground level adjacent to the foundation shall account for additional settlement of the backfill. Erosion Control In addition, appropriate erosion-control measures shall be taken at all times during construction to prevent surface runoff waters from entering footing excavations, ponding on finished building pad or pavement areas, or running uncontrolled over the tops of newly-constructed cut or fill slopes. Appropriate Best Management Practice (BMP) erosion control devices should be provided in accordance with local and federal governing agencies. Grading Plans Review Any future grading plans should be submitted to this office for review to ascertain that the recommendations provided in this report have been followed and that the assumptions utilized in its preparation are still. valid. Additional or amended recommendations may be issued based on this review. • FOUNDATIONS General Foundations for the structure should consist of continuous strip footings and/or isolated spread footings founded in compacted fill or competent natural ground. It appears recommendations for heaving soils are not required. Foundation Embedment Foundations should be constructed in accordance with the recommendations of the project structural engineer and the minimum requirements of the CBC. The following table provides suggested foundation dimensions. Proposed Residence March 11, 2019 Page 12 3159B Madison St. Carlsbad, CA C TABLE II- FOUNDATION DIMENSIONS Number of Floors Supported by TheFoundation Width of Footing (Inches) Embedment Depth Below Undisturbed Soil 1 12 12 2 15 18. 3 18 24 Soil Bearing Value The bearing level soils are anticipated to be comprised primarily of competent, silty sand (SM). Silty sands are considered Class of Materials 4, based on classification of these soils in accordance with the 1806A.2 Presumptive Load-Bearing Values of the California Building Code. Using Table 1806A.2 as a guideline the Allowable Foundation Pressure is 2000 pounds square foot (psf). The values presented herein are for dead plus live loads and may be increased by one-third when considering transient loads due to wind or seismic forces. Lateral Load Resistance Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be 0.4. The passive resistance may be considered to be equal to an equivalent fluid weight of 300 pounds per cubic foot in recompacted fill or firm natural ground material. This assumes the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced .by one- third. Foundation Reinforcement It is recommended that continuous footings be reinforced with at least four No. 4 steel bars; two reinforcing bars shall be located near the top of the foundation, and two bars near the bottom. The steel reinforcement will help prevent damage due to normal, post construction settlement or heaving, resulting from variations in the subsurface soil conditions. The minimum reinforcement recommended herein is based on soil characteristics • Proposed Residence March 11, 2019 Page 13 3159B Madison St. Carlsbad, CA only and is not intended to replace reinforcement required for structural considerations). Anticipated Settlements Based on our experience with the soil types on the subject site, the soils should experience settlement in the rnag:iitude of less than 0.5 inch under proposed structural loads. It should be recognized that minor hairline cracks normally occur in concrete slabs and foundations due to shrinkage during curing and/or redistribution of stresses and some cracks may be anticipated. Such cracks are not necessarily an indication of excessive vertical movements. Foundation Excavation Observation All foundation excavations should be observed by the Geotechnical Consultant prior to placing reinforcing steel and formwork in order to verify compliance with the foundation recommendations presented herein. All footing excavations should be excavated neat, level and square. All loose or unsuitable material should be removed prior to the placement of concrete. Foundation Plan Review The finalized, foundation plans should be submitted to this office for review to ascertain that the recommendat:ons provided in this report have been followed and that the assumptions utilized in its preparation are still valid. Additional or amended recommendations may be issued based on this review. Horizontal Distance of Footings from Slopes According to Section 1808.7 (Foundation on or adjacent to slopes), of the California Building Code, foundations on or adjacent to slope surfaces shall be founded in firm material with an embedment and set back from the slope surface sufficient to provide vertical and lateral support for the foundation without detrimental settlement. Generally, foundation setbacks should conform to Figure 1808A.7.1. CONCRETE SLABS-ON-GRADE It is our understanding that the floor system of the proposed structures will consist of concrete slab-on-grade floors. We anticipate that the concrete slabs-on-grade will be supported by non-detrimentally expansive, competent formation and/or properly compacted fill material. The following recommendations assume that the subgrade Proposed Residence Varch 11, 2019 Page 14 3159B Madison St. Carlsbad, CA 40 soils have been prepared in accordance with the recommendations presented in the "Grading and Earthwork" section of this report. In addition, the following recommendations are considered the minimum slab requirements based on the soil conditions and are not intended in lieu of structural considerations. Interior Floor Slabs: We recommend a minimum floor slab thickness of four inches (actual) is recommended for slab-on-grade floors. The floor slabs should be reinforced with at least No. 3 bars placed at 18 inches on center each way. Slab reinforcing should be supported by chairs and be positioned at mid-height in the floor slab. An expandable or compressible water stop is recommended at all foundation and floor slab joints and abutments that are below grade. Exterior Concrete Flatwork: On-grade exterior concrete slabs for walks and patios should have a thickness of four inches and should be reinforced with at least No. 3 reinforcing bars placed at 24 inches on center each way. Exterior slab reinforcement should be placed approximately at mid-height of the slab. Reinforcement and control joints should be constructed in exterior concrete flatwork to reduce the potential for cracking and movement. Joints should be placed in exterior concrete flatwork to help control the location of shrinkage cracks. Spacing of control joints should be in accordance with the American Concrete Institute specifications. When slabs abut foundations they should be doweled into the footings. Vehicular traffic should be avoided until the slab concrete is adequately cured. SLAB MOISTURE BARRIERS A moisture barrier system is recommended beneath interior slab-on-grade floors with moisture sensitive floor coverings or coatings to help reduce the upward migration of moisture vapor from the underlying subgrade soil. A properly selected and installed vapor retarder or barrier is essential for long-term moisture resistance and can minimize the potential for flooring and environmental problems related to excessive moisture. "Above-grade" interior floor slabs should be underlain by a minimum 10-mil thick moisture retarder product over a four-inch thick layer of clean sand material. (Please note additional moisture reduction and/or prevention measures may be needed, depending on the performance requirements for future floor covering products). All moisture retarder/moisture barrier products used should meet or exceed the performance standards dictated by ASTM E 1745 Class A material and be properly installed in accordance with ACT publication 302 (Guide to Concrete Floor and 0 Proposed Residence March 11, 2019 Page 15 3159B Madison St. Carlsbad, CA 49 Slab Construction) and ASTM E1643 (Standard Practice for Installation of Water Vapor Retarder Used in Contact with Earth or Granular Fill Under Concrete Slabs). Moisture Retarders and Installation Vapor retarder joints must have at least 6-inch-wide overlaps and be sealed with mastic or the manufacturer's recommended tape or compound. No heavy equipment, stakes or other puncturing instruments should be used on top of the liner before or during concrete placement. In actual practice, stakes are often driven through the retarder material, equipment is dragged or rolled across the retarder, overlapping or jointing is not properly implemented, etc. All these construction deficiencies reduce the retarders' effectiveness. It is the responsibility of the contractor to ensure that the moisture retarder is properly placed in accordance with the project plans and specifications and that the moisture retarder material is free of tears and punctures and is properly sealed prior to the placement of concrete. Interior Slab Curing Time Following placement of concrete floor slabs, sufficient drying time must be allowed prior to placement of floor coverings. Premature placement of floor coverings may result in degradation of adhesive materials and loosening of the finish floor materials. Prior to installation, standardized testing (calcium chloride test and/or relative humidity) should be performed to determine if the slab moisture emissions are within the limits recommended by the manufacturer of the specified floor- covering product. DESIGN PARAMETERS FOR EARTH RETAINING STRUCTURES The below foundation values are provided for conventional shallow foundations. Passive Pressure The passive pressure for the prevailing soil conditions may be considered to be 300 pounds per square foot per foot of depth. This pressure may be increased one-third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be 0.4 for the resistance to lateral movement. When combining frictional and passive resistance, the friction value should be reduced by one-third. Proposed Residence March 11, 2019 Page 16 3159B Madison St. Carlsbad, CA 0 I I S . I S I I I Soil Bearing Value Conventional spread footings with the above minimum dimensions may be designed for an allowable soil bearing pressure of 2,003 pounds per square foot for foundation bearing in compacted fill or firm natural ground. Active Pressure for Retaining Walls Lateral pressures acting against masonry and cast-in-place concrete retaining walls can be calculated using soil equivalent fluid weight. The equivalent fluid weight value used for design depends on allowable wall movement. Walls that are free to rotate at least 0.5 percent of the wall height can be designed for the active equivalent fluid weight. Retaining walls that are restrained at the top (such as basement walls), or are sensitive to movement and tilting should be designed for the at-rest equivalent fluid weight. Values given in the table below are in terms of equivalent fluid weight and assume a triangular distribution. The provided equivalent fluid weight values assume that onsite or imported, sandy soils (SF, SM, SC) with an Expansion Index (E.I.) of less than 20 will be used as backfill. No clay soils (CL-CH) should be used as retaining wall backfill. The retaining walls should be provided with adequate drainage. Expansion Index (E.I.) of less than 50 will be used as backfill. TABLE III Equivalent Fluid Weights (efw) For Calculating Lateral Earth Pressures (Using Non-detrimentally Expansive Backfill) Conditions Native Backfill (SM-SP) Active 30 pcf At-Rest 60 pcf Retaining Wall Foundations Retaining wall foundations shall be designed by the structural engineer based on the appropriate parameters provided in this report. Waterproofing and Subdrain Observation In general, retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and waterproofed as specified by the Proposed Residence March 1, 2019 Page 17 3159B Madison St. Carlsbad, CA • • 0 project architect. Also refer to American Concrete Institute AC! 515.11 (A Guide to the Use of Waterproofing, Damp Proofing, Protective and Decorative Barriers Systems for Concrete). Positive drainage for retaining walls should consist of a vertical layer of permeable material positioned between the retaining wall and the soil backfill. Such permeable material may be composed of a composite drainage geosynthetic or a natural permeable material such as crushed rock or clean sand at least 12 inches thick and capped with at least 12 inches of backfill soil. The gravel should be wrapped in a geosynthetic filter fabric. Provisions should be made for the discharge of any accumulated groundwater. The selected drainage system should be provided with a perforated collection and discharge pipe placed along the bottom of the permeable material near the base of the wall. The drain pipe should discharge to a suitable drainage facility. A typical retaining wall detail is attached as Figure No. 9. If lateral space (due to property line constraints) is insufficient to allow installation of the gravel-wrapped 'burrito" drain, a geocomposite system may be used in lieu of the typical gravel and pipe subdrain system. TenCate's MiraDrain (and similar products) provide a "low-profile drainage system that requires minimal lateral clearance for installation. MiraDRAIN and similar products may also be incorporated into a waterproofing system and provide a slab drainage system (Please note that supplemental manufacturer's details will be required to provide a waterproofed system). Backfill All backfill soils should be compacted to at least 90% relative compaction. Expansive or clayey soils should not be used for backfill material. The wall should not be • backfilled until the masonry has reached an adequate strength. FIELD INVESTIGATION Three test explorations were placed on the lot, using a hand auger sampling system. The excavations were placed specifically in areas where representative soil conditions were expected and/or where the proposed structures will be located. Our investigation also included a visual site reconnaissance. The excavations were visually inspected and logged by our field geologist, and samples were taken of the predominant soils throughout the field operation. Test excavation logs have been prepared on the basis of our inspection and the results have been summarized on Figures No. 3A through 3G. The predominant soils have been classified in conformance with the Unified Soil Classification System (refer to Appendix B). In • addition, a verbal textural description, the wet color, the apparent moisture and the Proposed Residence March 11, 2019 Page 18 3159B Madison St. Carlsbad, CA 0 density or consistency are provided. The density of granular soils is given as very loose, loose, medium dense, dense or very dense. The density of cohesive soils is given as either very soft, soft, medium stiff, stiff, very stiff, and hard. Disturbed and . relatively undisturbed samples of typical and representative soils were obtained from the test excavations and transported to the laboratory for testing. LABORATORY TESTS AND SOIL INFORMATION Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of the tests performed is presented below: CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System. MOISTURE-DENSITY: In-place moisture contents and dry densities were • determined for representative soil samples. This information was an aid to classification and permitted recognition of variations in material consistency with depth. The dry unit weight is determined in pounds per cubic foot, and the in-place moisture content is determined as a percentage of the soil's dry weight. The results are summarized in the test excavation logs. MAXIMUM DRY DENSITY: The maximum dry density and optimum moisture content of a typical soil were determined in the laboratory in accordance with ASTM Standard Test Pounds per square foot-1557, Method A. The results of this test are . presented on the following page. Sample Location B-i @ 1' to 2' Sample Description Dark brown, silty sand (SM-SP) Maximum Density 124 pcf . Optimum Moisture 10.1% LIMITATIONS The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the Geotechnical Engineer and Engineering Geologist so that they may review and verify their compliance with this report and with Appendix A and the • Proposed Residence March 11, 2019 Page 19 3159B Madison St. Carlsbad, CA 0 current California Building Code. It is recommended that C.W. La Monte Company Inc. be retained to provide soil-engineering services during the construction operations. This is to verify compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and/or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the Geotechnical Engineer so that he may make modifications if necessary. This office should be advised of any changes in the project scope or proposed site grading so that we may determine if the recommendations contained herein are appropriate. It should be verified in writing if the recommendations are found to be appropriate for the proposed changes or our recommendations should be modified by a written addendum. The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether they are due to natural processes or the work of man on this or adjacent properties. In addition, changes in the Standards-of-Practice and/or Government Codes may occur: Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and recommendations. In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our borings, surveys, and explorations are made, and that our data, interpretations, and recommendations are based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty • Proposed Residence March 11, 2019 Page 20 3159B Madison St. Carlsbad, CA 40 of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. Our firm will not be responsible for the safety of personnel other than our own on the site; the safety of others is the responsibility of the Contractor. The Contractor should notify the Owner if he considers any of the recommended actions presented herein to be unsafe. It is the responsibility of the stated client or their representatives to ensure that the information and recommendations contained herein are brought to the attention of the structural engineer and architect for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to insure that the contractor and his subcontractors carry out such recommendations during construction. The firm of C.W. La Monte Co. Inc. shall not be held responsible for changes to the physical condition of the property, such as addition of fill soils or changing drainage patterns, which occur subsequent to the issuance of this report. 0 0 0 0 Proposed Residence March 11, 2019 Page 21 3159B Madison St. Carlsbad, CA 0 SITE LOCATION AND TOPOGRAPHIC MAP 'U Buena Vista Lagoon "\ L-U.[NI T "\ lTA E!n. 9:j1N4 v - S EEAL'TIFUL c \OUP M0*4TOPI LUTt IfP,AIt TAN \\ S. klA'.Hot. 14 1 lei St Ptrn:". mt hh .i EkmS± orc6 .' HH Excerpt from USGS Topographic Map, San Luis Rey Quadrangle, 7.5-Minute Series, National Map Website C.W. La Monte Company Inc. Soil and Foundation Engineers LM S MADISON STREET PLOT PLAN AND GEOTECHNICAL MAP LEGEND Approximate Test B-2 Boring Location Geologic Units Qaf = Artificial Fill Qop =Old Paralic Deposits C. W La Monte Company ki 3159 B Madison Street Carlsbad, CA FIGURE NO. 2A sjrrF FLAN PROPOSED DEVELOPMENT LEGEND Approximate Test B-2 Boring Location 3159B = E -i----- L_- T ALLEY ILL1cT T1 . S S S 0 SAMPLE TEST EXCAVATION NO. B-i Elevation: Date: 03/06/20 19 Logged By: Method : Excavation Auger SOIL DESCRIPTION TOPSOIL 1. Dark brown, very moist, loose to medium 2 dense, silty sand 3 115 9.5 OLD PARALIC DEPOSITS (Qop) 4 Reddish brown to light brown, moist, 5 - medium dense to dense, silty sand 6 7. — — EXCAVATION BOTTOM Et SAMPLE TEST EXCAVATION NO. B-2 P Elevation:± Date: 02/18/20 16 Logged By:JBR Method : Excavati o'Hand Auger SOIL DESCRIPTION TOPSOIL 1 Dark brown, very moist, loose to medium 2 dense, silty sand 3 . 4 . .• . .• ------------------...--•---- ----------.--- OLD PARALIC DEPOSITS (Qop) 5 • • Reddish brown to light brown, moist, 6 .-..---- • medium dense to dense, silty sand 7 ................-........................•.......• ............................. ............•• ................................................................................................................................ .- I — — — EXCAVATION BOTTOM c w LMoncnIx Proposed Single-family Residence ,-, -, - - .. ..' - 3159 B Madison Street ....••) Carlsbad, CA -,. . FIGURE NO. 3 A C 0 0 0 AMPLE TEST EXCAVATION NO. B-i 'Elevation: Date: 03/06/2019 Logged By: Excavation Auger SOIL DESCRIPTION FILL 1 - Dark brown, very moist, loose to medium dense, silty sand with a little trash debris 2 3 - TOPSOIL Dark brown, very moist, loose to medium 4 - dense, silty sand - OLD PARALIC DEPOSITS (Qop) 6 - Reddish brown, to light brown, moist, medium dense to dense, silty sand - — — — EXCAVATION BOTTOM 97c, WE '-'"-'-' '''-' Proposed Single-family Residence ''-JJ 3159 B Madison Street ioEngees Carlsbad, CA FIGURE NO. 3B -/ Qop.7 :( GEOLOGY MAP EXCERPT Excerpt from. DIGIT-11. GLoLoc1c; M-IP OF TI-IL OCE4.SJI)L 30'X60, OL.-1DR-L'\GIJ, SOUTHLRX C-tLI1-ORX!A (2005), By Kennedy - Tan LEGEND (Localized) C. W. La Monte Company Inc. Qop = Old paralic deposits Soil and Foundation Engineers Fault - Solid where well defined: dashed where inferred. FIGURE 5 - Excerpt from: 2010 Fault Activity Map of California, Geologic Data Map No. 6 c::1 'N I Ohl 4 do / 0 134 .R .5 \ •',>. '\ok El I 'c" SUMMARY EXPLANATION Fault traces on land are indicated by solid lines where well located, by dashed lines where approximately located or inferred, and by dotted lines where concealed by younger rocks or by lakes or bays. Fault traces are queried where continuation or existence is uncertain. FAIIT CLASSIFICATR)N COLOR ('ODE (Indicating Recency of Movement) Late Quaternary fault (during past 700,000 years). - - -- ' Historic Fault (last 200 years) _______ l--Iolocene fault (during past 11,700 years) without historic record. - - Pre-Quaternary fault (older that 1.6 million years) or fault ...........Quaternary fault (age undifferentiated) without recognized Quaternary displacement. Appendix "A" STANDARD GRADING AND CONSTRUCTION SPECIFICATIONS Ll Ll Appendix "A" STANDARD GRADING AND CONSTRUCTION SPECIFICATIONS These specifications present the usual and minimum requirements for projects on which C.W. La Monte Company is the geotechnical consultant. No deviation from these specifications will be allowed, except where specifically superseded in the preliminary geology and soils report or in other written communication signed by the Soils Engineer or Engineering Geologist of record. GENERAL The Soils Engineer and Engineering Geologist is the Owner's or Builders' representative on the Project. For the purpose of these specifications, participation by the Soils Engineer includes that observation performed by any person or persons employed by, and responsible to, the licensed Civil Engineer signing the soils reports. All clearing, site preparation, or earthwork performed cm the project shall be conducted by the Contractor under the supervision of the Soils Engineer. It is the Contractor's responsibility to prepare the ground surface to receive the fills to the satisfaction of the Soils Engineer and to place, spread, mix, water, and compact the fill in accordance with the specifications of the Soils Engineer. The Contractor shall also remove all material considered unsatisfactory by the Soils Engineer. It is also the Contractor's responsibility to have suitable: and sufficient compaction equipment on the job site to handle the amount of fill being placed. If necessary, excavation equipment will be shut down to permit completion of compaction. Sufficient watering apparatus will also be provided by the Contractor, with due consideration for the fill material, rate of placement, and time of year. A final report shall be issued by the Soils Engineer attesting to the Contractor's conformance, with these specifications. SITE PREPARATION All vegetation and deleterious material shall be disposed of off site. This removal shall be concluded prior to placing fill. Soil, alluvium, or bedrock materials determined by the Soils Engineer, as being unsuitable for placement in compacted fills shall be removed from the site. The Soils Engineer must approve any material incorporated as a part of a compacted fill. After the ground surface to receive fill has been cleaced, it shall be scarified, disced, or bladed by the Contractor until it is uniform and free from ruts, hollows, hummocks, or other uneven features which may prevent uniform compaction. The scarified ground surface shall then be brought to optimum moisture, mixed as required, and compacted as specified. If the scarified zone is greater than 12 inch--s in depth, the excess shall be removed and placed in lifts restricted to 6 inches. Prior to placing fill, the ground surface to receive fill shall be inspected, tested as necessary, and approved by the Soils Engineer.' Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic tanks, wells, pipe lines, or others are to be removed or treated in a manner prescribed by the Soils Engineer and /or governing agency. In order to provide uniform bearing conditions in cut-fill transition lots and where cut lots are partially in soil, colluvium, or un-weathered bedrock materials, the bedrock portion of the lot extending a minimum of 3 feet outside of building lines shall be over excavated a minimum of 3 feet and replaced with compacted fill. 0 Appendix A Standard Grading and Construction Specificatins Page 2 COMPACTED FILLS Any material imported or excavated on the property may be utilized in the fill, provided each material has been determined to be suitable by :he Soils Engineer. Roots, tree branches, and other matter missed during clearing shall be removed from the fill as directed by the Soils Engineer. Rock fragments less than 6 inches in diameter may be utilized in the fill, provided: 1.. They are not placed in concentrated pockets: There is a sufficient percentage of fine-grained material to surround the rocks. The Soils Engineer shall supervise the distribution of rocks. C Rocks greater than 6 inches in diameter shall be taken off site, or placed in accordance with the recommendations of the Soils Engineer in areas designated as suit-able for rock disposal. Material that is spongy, subject to decay or otherwise considered unsuitable should not be used in the compacted fill. Representative samples of material to be utilized as compacted fill shall be analyzed by the laboratory of the Soils Engineer to determine their physical properties. If any material other than that previously tested is encountered during grading, the appropriate analysis of this material shall be conducted by the Soils Engineer as soon as possible. F. Material used in the compaction process shall be evenly spread, watered processed, and compacted in thin lifts not to exceed 6 inches in thickness to obtain a uniformly dense layer. The fill shall be placed and compacted on a horizontal plane, unless otherwise approved by the Soils Engineer. If the moisture content or relative density varies from that required by the Soils Engineer, the Contractor should re-work the fill untii the Soils Engineer approves it. Each layer shall be compacted to 90 Percent of the maximum density in compliance with the testing method specified by the controlling governmental agency. (In general, ASTM D-1 557-91, the five-layer method will be used.) If compaction to a lesser percentage is authorized by the controlling governmental agency because of a specific land use or expansive soils condition, the area to receive fill compacted to less than 90 percent shall either be delineated on the grading plan or appropriate reference made to the area in the soils report. - H. All fills shall be keyed and benched through all topsoil, colluvium, alluvium or creep material, into sound bedrock or firm material excep: where the slope receiving fill exceeds a ratio of five horizontal to one vertical, in accordance with the recommendations of the Soils Engineer. I. The key for hillside fills should be a minimum of 15 feet in width and within bedrock or similar materials, unless otherwise spec:fied in the soil report. Subdrainage devices shall be constructed in compliance with the ordinances of the controlling governmental agency, or with the recommendations of the Soils Engineer or Engineering Geologist. The contractor will be required tD obtain a minimum relative compaction of 90 percent out to the finish - slope face of fill slopes, buttresses, and stabilization fills. This may be achieved by either overbuilding the slope and cutting back to the compacted core, or by direct compaction of the slope face with suitable equipment, or by any other procedure which produces the required compaction. 0 Appendix A Standard Grading and Construction Specifications Page 3 M. All fill slopes should be planted or protected from erosion or by other methods specified in the soils report. N. Fill-over-cut slopes shall be properly keyed through topsoil, colluvium or creep material into rock or firm materials, and the transition shall be stripped of all soil prior to placing fill. CUT SLOPES The Engineering Geologist shall inspect all cut slopes at vertical intervals not exceeding 10 feet. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Soils Engineer, and recommendations shall be made to treat these problems. Cut slopes that face in the same direction as the prevailing drainage shall be protected from slope wash by a non-erodible interceptor swale placed at the top of the slope. Unless otherwise specified in the soils and geological report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of controlling governmental agencies. Drainage terraces shall be constructed in compliance with the ordinances of controlling governmental agencies, or with the recommendations of the Soils Engineer or Engineering Geologist. GRADING CONTROL Observation of the fill placement shall be provided by the Soils Engineer during the progress of grading. in general, density tests should be made at intervals not exceeding 2 feet of fill height or every 500 cubic yards of fill placement. This criteria will vary, depending on soil conditions and the size of the job. In any event, an adequate number of field density tests shall be made to verily that the required compaction is being achieved. C. Density tests may also be conducted on the surface material to receive fills as determined by the Soils Engineer. D. All clean-outs, processed ground to receive fill, key excavations, subdrains, and rock disposals must be inspected and approved by the Soils Engineer or Engineering Geologist prior to placing any fill. It shall be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for inspection. CONSTRUCTION CONSIDERATIONS A. The Contractor shall provide necessary erosion control measures, during grading and prior to the completion and construction of permanent drainage controls. B. Upon completion of grading and termination of inspections by the Soils Engineer, no further filling or excavating, including that necessary for footings, foundations, large tree wells, retaining walls, or other features shall be performed without the approval of the Soils Engineer or Engineering Geologist. C. Care shall be taken by the Contractor during final grading to preserve any berms, drainage terraces, interceptor swales, or other devices of permanent nature on or adjacent to the property. D. In the event that temporary ramps or pads are constructed of uncontrolled fill soils during a future grading operation, the location and extent of the loose fill soils shall be noted by the on-site representative of a qualified soil engineering firm. These materials shall be removed and properly recompacted prior to completion of grading operations. E. Where not superseded by specific recommendations presented in this report, trenches, excavations, and temporary slopes at the subject site shall be constructed in accordance with section 1541 of Title 8, Construction Safety Orders, issued by OSHA. Appendix A Standard Grading and Construction Specifications Page 4 APPENDIX " B" UNIFIED SOIL CL 4SSIFICA HON CHART SO! L DESC RI PT! ON I COARSE GRAINED: More than half of material is largerhan No. 200 sieve size. GRAVELS: More than half of coarse fraction is larger than No.4 sieve size but smaller than 3'. GROUP SYMBOL TYPICAL NAMES CLEAN GRAVELS GW Well graded gravels, gravel-sand mixtures, little or no fines, GP Poorly graded gravels, gravel sand mixtures, little or no fines GRAVELS WITH FINES GM Silty gravels, poorly graded gravel- sand-silt mixtures (Appreciable amount of fines) GC Clayey gravels, poorly graded gravel sand, clay mixtures. SANDS: More than half of coarse fraction is smaller than No. 4 sieve size CLEAN SANDS SW Well graded sand, gravelly sands, little or no fines SP Poorly graded rands, gravelly sands, little or no fines SANDS WITH FINES SM Silty sands, poorly graded sand and silty mixtures. (Appreciable amount of fines SC Clayey sands, poorly graded sand and clay mixtures IL FINE GRAINED: More than half of material is smaller than No. 200 sieve size SILTS AND CLAYS ML Inorganic silts and very fine sands, rock flour, sandy silt • - or clayey-silt .vith slight plasticity. Liquid Limit CL Inorganic clay of low to medium plasticity, Less than 50 gravelly clays, 3andy clays, silty clays, lean clays OL Organic silts and organic silty clays of low plasticity • SILTS AND CLAYS MR Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silt Liquid Limit CH Inorganic clays, of high plasticity, fat clays. greater than 50 OH Organic clays ef medium to high niasticity. HIGHLY ORGANIC SOILS • PT Peat and other highly organic soils.