Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
PD 2022-0001; ISBELL RESIDENCE; REPORT OF LIMITED GEOTECHNICAL INVESTIGATION; 2021-08-03
C. W. la Moruie Company lmc. Soil and Foundation Engineers REPORT OF LIMITED GEOTECHNICAL INVESTIGATION Proposed Single-family Residence Vacant Lot Adjacent to 2936 Cacatua St. Carlsbad, CA APN 215-390-35 JOB NO. 21 7424 August 30, 2021 Prepared for: Scott and April Isbell Cfo MLA General Contractor P.O. Box 733 Bonsall, CA 92003 Attn: TJ Amos 7840 EL CAJON BLVD., SUITE 200 ■ LA MESA, CALIFORN IA 91942 Phon e: (619) 462-9861 ■ Email: Clamonte@Flash.Net ■ Fax: (619) 462-9859 C. W. La Monte Company Inc. Soil and Foundation Engineers 7840 EL CAJON BLVD., SUITE 200 ■ LA MESA, CALIFORNIA 91942 Phone: (619) 462-9861 ■ Email: Clamonte@Flash.Net ■ Fax: (619) 462-9859 August 03 , 2021 Job No. 21 7424 TO: Scott and April Isbell C/ o MLA General Contractor P.O. Box 733 Bonsall, CA 92003 Attn: TJ Amos SUBJECT: Report of Limited Geotechnical Investigation Proposed Single-family Residence Vacant Lot Adjacent to 2936 Cacatua St. Carlsbad, CA APN 215-390-35 In accordance with your request and our proposal dated August 12, 2021 we have performed a geotechnical investigation for the proposed residential project. We are presenting herewith our findings, conclusions, and recommendations. In general, we found the site suitable for the proposed project provided that the recommendations contained herein are adhered to. Our subsurface explorations revealed the site to exist as a cut ground lot excavated into competent sedimentary bedrock. The project will only require minimal site preparation mitigation, assuming the s tructure will be constructed at or near the existing pad grade. If you should have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, C. W. La Monte Company Inc. ~t,)-~~ Clifford W. La Monte, R.C.E. 25241, G.E. 0495 r~ W.t.o, ~ Exp. 12/31/2021 No. 495 TABLE OF CONTENTS PROJECT DESCRIPTION ............................................................................................... 1 SCOPE OF WORK ........................................................................................................... 1 FINDINGS ......................................................................................................................... 3 SITE DESCRIPTION AND HISTORY ........................................................................... 3 DESCRIPTION OF SUBSURFACE SOIL CONDITIONS ........................................... 4 GROUND WATER .......................................................................................................... 4 SEISMICITY AND FAUL TING ...................................................................................... 5 SEISMIC DESIGN PARAMETERS ................................................................................ 6 GEOLOGIC HAZARDS .................................................................................................. 7 CONCLUSIONS ............................................................................................................... 8 RECOMMENDATIONS .................................................................................................. 9 EARTH WORK AND GRADING .................................................................................. 9 Specifications and Preconstruction ......................................................................... 9 Site Preparation ......................................................................................................... 9 Compaction and Method of Filling ........................................................................ 9 Surface Drainage ..................................................................................................... 10 Erosion Control ........................................................................................................ 10 Temporary Cut Slopes ............................................................................................ 10 FOUNDATIONS ............................................................................................................ 11 Dimensions and Embedment ................................................................................ 11 Reinforcement .......................................................................................................... 12 Anticipated Settlements ......................................................................................... 12 Foundation Plans Review ...................................................................................... 12 CONCRETE SLABS-ON-GRADE ................................................................................ 12 Exterior Concrete Flatwork .................................................................................... 12 SLAB MOISTURE BARRIERS ...................................................................................... 13 Interior Slab Curing Time ...................................................................................... 14 DESIGN PARAMETERS FOR EARTH RETAINING STRUCTURES .................... 14 Passive Pressure ...................................................................................................... 14 Soil Bearing Value ................................................................................................... 14 Active Pressure for Retaining Walls ..................................................................... 14 Retaining Wall Foundations .................................................................................. 15 Waterproofing and Subdrain Observation .......................................................... 15 Backfill ....................................................................................................................... 16 FIELD INVESTIGATION .............................................................................................. 16 LABORATORY TESTS AND SOIL INFORMATION ............................................... 16 LIMITATIONS ................................................................................................................ 17 TABLES Table I Table II Table III Mapped Spectral Acceleration Values and Design Foundation Embedment Equivalent fluid weights ATTACHMENTS FIGURES Figure No. 1 Figure No. 2 Site Location Map (Topo) Plot Plan and Geotechnical Map Test Boring Logs Page6 Page 13 Page 17 Figure No. 3 A through 3E Figure No. 4 Figure No. 5 Figure No. 6 Regional Geologic Map Excerpt (2005) Regional Fault Activity Map Landslide Hazard Map Figure No. 7 Suggested Retaining Wall Details APPENDICES Appendix 11A"-Standard Grading Specifications Appendix 11B11 -Unified Soil Classification Chart REPORT OF LIMITED GEOTECHNICAL INVESTIGATION Proposed Single-family Residence Vacant Lot Adjacent to 2936 Cacatua St. Carlsbad, CA APN 215-390-35 PROJECT DESCRIPTION The following report presents the results of a limited geotechnical investigation performed for the proposed residential project. The project site is a vacant residential lot, approximately 1/3 of an acre in size and located west of and adjacent to 2936 Cacatua 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. It is our understanding the site is being developed to receive a custom home, which is still in the planning phase. We anticipate the proposed structure will be a maximum of two-stories in height and will be founded on conventional shallow foundations with a slab-on-grade floor. The structure will be constructed at or near the existing lot grade. To aid in the preparation of this report, we were provided with an undated, unreferenced topographic map provided by the client. This plan was used for our field mapping and to prepare our Plot Plan and Geotechnical Map (Figure 2), 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. 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 geotechnical reports and maps pertinent to the subject site. • 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 geotechnical 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 of 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. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page2 FINDINGS SITE DESCRIPTION AND HISTORY The vacant property is located west of and adjacent to 2936 Cacatua Street in the City of Carlsbad, California. The site is bounded on the north, east and west with single- family homes and on the south with Cacatua Street. A legal description of the property is Assessor's Parcel Number 215-390-35-00. The property is irregular- shaped and is approximately 13,000 square feet in area with about 70 feet of slightly radial frontage along Cacatua Street. Vegetation consists of a light growth of grass weeds, and shrubs. The lot was graded as a relatively level, cut ground building pad. A cut slope approximately 7 feet in maximum height, ascends along the east side of the property. A review of historic aerial photographs (HistoricAerials.com) indicates that grading for the site and surrounding subdivision occurred in the late 1970's. The slope was constructed at an approximate 1.7:1.0 (horizontal to vertical) to 2.0:1.0 inclinations. A cut slope approximately 5 feet in maximum height, descends from the southwest corner of the lot to the adjacent street. This cut is inclined at approximately 3.5:1. A concrete lined drainage ditch crosses the north end of the site and provides drainage control for this portion of the subdivision. Elevations on the site range from a high of approximately 506 feet (MSL) along the top of the easterly cut slope to a low of about 492 feet in the bottom of the drainage ditch near the northwest property corner. The average building pad elevation is on the order of 497 feet. Prior to grading the site topography consisted of hillside terrain sloping moderately to the west. An excerpt from a historic topographic map is presented below depicting the pregrading topography. Proposed Residence Cacatua St. Carlsbad, CA . Excerpt from USGS Topographic Map, 1968, 7.5' August 30, 2021 Page3 DESCRIPI'ION 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 Tertiary-aged sedimentary formational deposits with associated surficial materials and minor surficial fills. These soil types are described individually below in order of increasing age. Also refer the attached Test Boring Logs, Figure No. 3A through 3E. A Plot Plan and Geotechnical Map are attached as Figure No. 2 with the test boring locations a mapping of the encountered units. An excerpt from a regional geologic map is included as Figure No. 4. Fill: The building pad is capped with a thin veneer of disturbed fill soils consisting of brown, loose, sandy silts. The encountered fills ranged in thickness from just a few inches to about 8 inches. Santiago Formation (Tsa): According to the Digital Geologic Map of the Oceanside 30' X 60' Quadrangle, Southern California (2005), l?J Kennet!, -Tan (Kenned and Tan, 2005), the site is underlain at depth with competent and Tertiary-aged sediments. The formation is exposed at or near the ground surface on the building pad and forms the onsite cut slopes (described previously). The encountered formational materials consist primarily of light brown to light gray, very dense, silty sandstone and greenish-gray, hard siltstone. GROUNDWATER No groundwater was encountered in our test excavations at the time of our investigation. 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 Cacatua St. Carlsbad, CA August 30, 2021 Page4 SEISMICITY AND FAULTING 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 are 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" faults (California Probabilistic Seismic Hazard Maps, June 2003. 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 Cacatua St. Carlsbad, CA August 30, 2021 PageS 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 Alquist-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 Standards 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 St Fa Fv Sms Smt Sds Sdt PGA 0.934 0.342 1.2 1.5 1.121 0.513 0.747 0.342 0.406 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. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page6 GEOLOGIC HAZARDS 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 to medium-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 Cacatua St. Carlsbad, CA August 30, 2021 Page7 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. CONCLUSIONS 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 exists with a level cut ground building pad exposing competent sedimentary bedrock at or near the ground surface of the building pad. The exposed formational deposits will provide adequate support for proposed structural improvements. Therefore, only minimal site preparation is required, assuming the proposed structure will be constructed at or near the existing pad grade. We anticipate all building footings will be founded in competent formational bedrock. • Minor loose fills overlie the pad ranging from a few inches to about 8 inches in thickness. Only minimal site preparation is anticipated to develop the site. Due to potential disturbance by site clearing and surficial fills, the floor slab subgrade may require processing. • Existing cut slopes, a maximum of 7 feet in height, are excavated into competent formational deposits and are considered stable. Except for possible use of structural retaining walls, we understand the project will not include any significant modifications to the existing slopes. • The building site is not underlain with a cut-fill transition. • The foundation level materials encountered at the site are considered to possess a very low to medium expansion potential ( expansion index [EI] less than 20) as defined by ASTM D4829. Recommendations for heaving soils are not required. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page8 RECOMMENDATIONS EARTH WORK AND GRADING Specifications and Preconstruction Any future grading should conform to the guidelines presented in this report, Sections 1804 and Appendix "J" of the 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. Site Preparation Site preparation should begin with the removal of all vegetation and any other deleterious materials from the area of the proposed construction. The resulting organic materials and debris should be disposed of in an appropriate off-site facility. No significant additional site grading is anticipated. As such, only minimal grading specifications have been included in this report. Should the scope of the project change to include significant grading, we should be contacted to provide the necessary site preparation recommendations and grading specifications. The subgrade for any areas receiving a new interior and exterior slab-on-grade, should be scarified to a depth of approximately 8 inches, moisture conditioned, and compacted to at least 90 percent relative compaction. Compaction and Method of Filling Any structural fill placed at the site should be compacted to a relative compaction of at least 90 percent of its maximum dry density as determined by ASTM Laboratory Test D1557 guidelines. 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. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page9 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. Surface Drainage Per Section 1804 of the California Building Code, in general, the ground immediately adjacent to foundations 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 (3048 mm) measured perpendicular to the face of the wall. If physical obstructions or lot lines prohibit 10 feet (3048 mm) of 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 (3048 mm) of the building foundation. Impervious surfaces within 10 feet (3048 mm) of the building foundation shall be sloped a minimum of 2 percent away from the building. Exceptions are allowed where climatic or soil conditions warrant, the slope of the ground away from the building foundation shall be permitted to be reduced to not less than one unit vertical in 48 units horizontal (2-percent slope). 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. Temporary Cut Slopes No temporary cuts exceeding 4 feet in height are anticipated, therefore, specific recommendations for temporary slopes are not included in this report. However, 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 Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 10 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. FOUNDATIONS Based on the findings of our investigation, it is our opinion the proposed structures may be supported by conventional continuous and isolated spread footings deepened if necessary to bear in competent natural ground. The on-site materials generally possess a low to moderate expansive potential and therefore, consideration for heaving soils is included in our recommendations. Soil Design Values The bearing level soils are anticipated to be comprised of dense, bedrock formational deposits. Using Table 1806A.2 (Presumptive Load-Bearing Values) as a guideline the below soil design values may be used in the design of foundations: Allowable Foundation Pressure: 3000 pounds square foot (psf) (Bearing in firm natural ground) Lateral Pressure: 350 pounds/ square ft. / ft. of depth Lateral Sliding Coefficient: 0.3 This bearing value may be increased by one-third for loads of short duration including wind or seismic forces. Dimensions and Embedment Foundations should be constructed in accordance with the minimum requirements of the California Building Code and the recommendations of the project structural engineer or architect. Due to potentially expansive subgrade conditions it is recommended all new perimeter foundations be embedded at least 18 inches below the lowest adjacent grade. The foundation width shall be 12 and 15 inches (respectively) for one and two-story structures. In addition to the above minimum embedment, footings may require deepening if unexpected deeper fills are encountered. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 11 Reinforcement Any required foundation reinforcement shall be determined by the project structural engineer and architect. However, any new continuous footings should be reinforced with at least two No. 5 steel bars; one reinforcing bar shall be located near the top of the foundation, and one bar near the bottom. Anticipated Settlements Based on our experience with the soil types on the subject site, the soils supporting the structure should experience settlement in the magnitude 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 Plans Review The finalized, foundation 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. CONCRETE SLABS-ON-GRADE We understand the proposed addition will be on raised floor and therefore recommendations for interior slabs are not included in this report. Exterior slab recommendations are provided below: 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 18 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 Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 12 the American Concrete Institute specifications. Foundations they should be doweled into the footings. Site Preparation for Slabs-on-Grade Floors The upper 8 inches of subgrade soil supporting new slabs should be processed and recompacted. The exposed soils should be scarified and/ or removed to a depth of approximately 6 to 8 inches, be moisture conditioned, and compacted to at least 90 percent relative compaction. 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 ACI publication 302 ( Guide to Concrete Floor and 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 Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 13 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 masonry retaining walls. Passive Pressure The passive pressure for the prevailing soil conditions may be considered to be 350 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 0.35 for the resistance to lateral movement. When combining frictional and passive resistance, the friction value should be reduced by one-third. Soil Bearing Value Conventional spread footings with the above minimum dimensions may be designed for an allowable soil bearing pressure of 2,000 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. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 14 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 imported or onsite granular soils will be used as backfill. Table II Equivalent Fluid Weights (efw) For Calculating Lateral Earth Pressures (Using "Select" Backfill) Surface Slope Of Cantilever Equivalent Restrained Equivalent Retained Material Fluid weight Fluid Weight (Horizontal To Vertical) (active pressure) ( at-rest pressure) (pcf) (pcf) LEVEL 38 60 2:1 51 76 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 project architect. Also refer to American Concrete Institute ACI 515.R (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. Typical retaining wall detail options are attached as Figure No. 7. 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 Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 15 the typical gravel and pipe subdrain system. TenCate's MiraDrain (and similar products) provide a 11low-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 Five 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 3C. 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 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. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 16 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. EXPANSION INDEX: Expansion Index testing on a remolded sample was performed on a representative sample in accordance with ASTM D4829 as a guideline. EXPANSION INDEX TEST Sample Location: B-2 , 0.5' -1.5' Initial Moisture Content: 15.0% Initial Dry Density: 105.0 Final Moisture Content: 20% Expansion Index: 48 CBC Classification: Low to Medium 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 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 Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 17 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 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 Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 18 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. Proposed Residence Cacatua St. Carlsbad, CA August 30, 2021 Page 19 SITE LOCATION AND TOPOGRAPHIC MAP ,· fAt-AC,A sr l,u\..-' Scale: 1 :9 028 Zoom Leve : 16 0 ~" 600ft '<· -~--1l724533.118Degree5 "' Excerpt from USGS Topographic Map, Rancho Santa Fe Quadrangle, 7.5-Minute Series, National Map Website C.W. La Monte Company Inc. tJ" Soil and Foundation Engineers Figure No. 1 \ ' ~497.7 • \ Tsa \ I • \· ' r4975 \ ' B-2 ' \ ~ r497.2 ' !\ ~\ .. ' i\ \ I \ .~,. \ ' \ B-1 ~ ~~ s sr42'45" w 35.oa B-3 ~ B-4 ·~ I I ~-An RISER PLOT PLAN AND GEOTECHNICAL MAP LEGEND Approximate Test Boring Location Geologic Unit ~B-2 Tsa = Santiago Formation A '•\ 7 0 10 20 30 --------- TELECOMM BOX c-_-• □ i!.t!°<D ~___:....:;;a.,----:-----:--r------- ST. LIGHT___./".; ~ ELE C BOX C. W .. la~~ lllt. SQillandlJQI ' •. lit~ CONCRETE CURS & GUTTER . . r EXISTING 8" V.C.P. SEWER MAIN PER SHEET 12 OF 25-TM288T-3. OWG NO 1884 -·~------·---·--& -·----·--•------\---·--------- -\__ EXISTING lr'AC WATER MAIN PER SHEET 12 OF 25-TM 2887-3, OWG NO 188- Cacatua St., Carlsbad, CA APN 215-390-35 FIGURE NO. 2 rn G;' TEST EXCAVATION B-1 fa;1 -u .:I E--~ °"4 z °"4 0 --0 C' ! ~ 0 ~ >-5~ Surface Elevation: -496.5' Date: 08/27/2021 ~ r-. E--Logged By: JBR -rn :::::> -C'.) C'.) -rn ... f: Cl rn E--;z; ~ fl.) l'al ~ rn fa;1 ~~ Excavation Method: Hand Auger i -~ 0 0 Q ~ r;i.l ::.: .:I ~ ~ ,.J ~ ~ = C'.) :> = Q DESCRIPTION OF SUBSURFACE CONDITIONS FILL Brown and light brown, dry, loose, sandy silt -ML "' with some small concrete debris - -SANTIAGO FORMATION (Tsa} 1 -~ SM Light brown, dry, very dense, silty sandstone -@ one foot becomes light gray -~ - 2 ~ @ two feet practical refusal with hand auger EXCAVATION BOTTOM - - - 3 - - - - 4 - - - - 5- - - - 6 - t.W .. taM"ma~IImf .. PROJECT: Cacatua St., Carlsbad, CA APN 215-390-35 ~ill and!:huod~•Bngt~IIS3 FIGURE NO. 3 A r:ll -r.. TEST EXCAVATION B-2 r-1 -u ...;i E-~ 0 0... z 0... 0 --0 ~ ~ 0 -~ ~ > ~~ ~ < r.. E-Surface Elevation: -497 .5' Date: 08/27/2021 Logged By: IBR .._.. r:ll -;:;i -uu r:ll ;: ~ ~ Q r:ll E-c z ~ :; r:ll ril ;:i Excavation Method: Hand Auger ; -r-1 ~ 0 0 Q Cl.) < ra-1 ~ ti ...;i ~ ~ ~ = ~ = u ;;;) ; = Q DESCRIPTION OF SUBSURFACE CONDITIONS ML FILL Brown and light brown, dry, loose, sandy silt ~ with some small concrete debris -~ SANTIAGO FORMATION {Tsa} -~ ML Greenish gray, dry, hard, sandy siltstone 1 -~ - -~ - 2 @ two feet practical refusal with hand auger EXCAVATION BOTTOM - - - 3 - - - - 4 - - - - 5- - - - 6 - C. Wo. ILa~~' ko, PROJECT: Cacatua St., Carlsbad, CA APN 215-390-35 ~illandil'QnndatiQlll~ FIGURE NO. 3 B \ \ ' / ,, ~ ~ .! ._, ~ ~ r-1 = - - 1 - - - - 2 - - - 3 - - - - 4 - - - - 5- - - - 6 - Cll G;' TEST EXCAVATION B-3 rilil -u ~ f-1 ~ 0 a.. z a.. 0 --0 ~ 0 > -~ ~~ Surface Elevation: -497 .5' Date: 08/27/2021 r-.. ~ Logged By: IBR 00 ~ -uu -00 5~ Cl Cll f-1 z r;i;;i ~ Cll rilil t'll -' Excavation Method: Hand Auger ~ ..... 0 0 Q ~ :::i :id ti; ~ ~ ~ .I 5 i:i = u IIQ z Q DESCRIPTION OF SUBSURFACE CONDITIONS :::i ML FILL Brown and light brown, dry, loose, sandy silt \. SANTIAGO FORMATION {Tsa) SM Light brown, dry, very dense, silty sandstone @ 1.5 feet refusal on cemented layer or concretion EXCAVATION BOTTOM C.W(Jra~~ .,. PROJECT: Cacatua St., Carlsbad, CA APN 215-390-35 SQjJJamilJ8Jlll®ti~lll~ FIGURE NO. 3 C {I.) " TEST EXCAVATION B-4 la;1 -u .,;i e,. ~ ~ z ~ 0 0 -0 ,;-~ ~ > -~ ~ t;; Cl¾ Surface Elevation: 497' Date: 08/27/2021 ~ e,. Logged By: JBR .._, {I.) -;:i -uu {I.) ;: rJ3 = = 00 e,. z ~ r..i ~ 00 la;1 ~ ;:i Excavation Method: Hand Auger = -=-0 0 Q Cl.) < r-1 ~ ~ ...;i ~ ~ ...;i ~ ..i Cll = u :) 8 IQ z Q DESCRIPTION OF SUBSURFACE CONDITIONS :) FILL Brown and light brown, dry, loose, sandy silt -ML \ with some small concrete debris - -SANTIAGO FORMATION (Tsa} 1 -SM Light brown, dry, very dense, silty sandstone -@ one foot becomes light gray - - 2 @ two feet practical refusal with hand auger EXCAVATION BOTTOM - - - 3 - - - - 4 - - - - 5- - - - 6 - C.W .. laMmm~ Inf .. PROJECT: Cacatua St., Carlsbad, CA APN 215-390-35 SQilland!D'Qund~tiQ~~ FIGURE NO. 3 D 00 -~ TEST EXCAVATION B-5 ~ -u -I Ei-';fe. ~ z =---0 -0 i' ! ~ > -~ ~ Ei-~"¾ Surface Elevation: ~503' Date: 08/27/2021 Logged By: JBR -00 :::> 1-4 uu -r:l.l fi: c,3 i9 Q 00 Ei-z '11:l ~ 00 ci1 .) Excavation Method: Hand Auger ~ 1-4 ~ ~ 0 0 = fl.) < l;a;1 ~ ~ .:i ~ ~ ,..;i = s fl.I = u m ; Q DESCRIPTION OF SUBSURFACE CONDITIONS ML FILL Brown and light brown, dry, loose, sandy silt \ with some small concrete debris -SANTIAGO FORMATION (Tsa} - ML Greenish gray, slightly moist to moist, hard, 1 -sandy, clayey siltstone - - - 2- - - - @ 3 feet practical refusal with hand auger 3 EXCAVATION BOTTOM - - - 4 - - - - 5- - - - 6 - C. W.. Ea~~ ilt. PROJECT: Cacatua St., Carlsbad, CA APN 215-390-35 ~iJJ andf JQuJldalmlll&J~~ FIGURE NO. 3 E GEOLOGY MAP EXCERPT Mzu Excerpt from: GEOLOGIC MAP OF THE OCEANSIDE 30' X 60' QUADRANGl .c, C/11 .!FOR.NJ.A , REGIONAL GEOLOGIC MAP NO. 2 (2007), By Kennedy -Tan C .. W/o. ~ M0nt~i C0~:w •~- ~ill an~ HQun.datj~n.1En~~rs, LEGEND (Localized) Tsa = Santiago Formation Mzu = Metamorphic Rock Fault -Solid where well defined; dashed where inferred. ···••••••••••••••••••••• --- Figure No 4 FIGURE 5-Excerpt from: Fault Activity Map of California, CGS \~·--• r:) ~ / ' .... ~- ' '\,0 )'. S,>CSme," \"\. .,.,( \"---~,..,,, ,~ ~ • I =•/ I .,_ '-, ,,_,_ / '••• , ""~._ 11,,/} \\ • "-,...__ -~"It, ( Pc,,_ 1,1.,rm ; "\. '?~ --~ ,, oo., \ \ ~-~" :,\ ;\,, ,.c ... 'r/ ' \ , / \ ~1 r \~ ~ , '\ ~ l ,, '' ,__ l.... \ . I> -' ' :---,..__ /-,ti~ ' "~ ,q ~, ~l,1,, •d•·~ \' (/ ( • "\ -......,.f.J2 h \ ,,'1~, . '-.l'-'ll>, ),. """ ~ ,-<t '' ~"'-\ ~ . ~-~ ,.r--:~~I~~~ '----~ ,E: ~--~ \ .,,,,,,-I '-~~ ~",j/~ ~' -.~ ',J·"'·-~::, ~~•-52o N_ -. ' rt.,. 70 •. ~ Lo, Co,ai ............ RP ~ y.JIIOll~ --Lu 'f,.,9-4-"" ~ , .k] \ ~ I ~ .,..,., .. ~ ~ ·. 1= ,1llbruok ':-- .-.,,,lPI ' •• ~--"•, \ '\\ ', ' '~---~\ ~ '-, '-\ ,::_ \ \ \ ~oc.,a11~1c1., \ \ ,\ \ ~ ~ (.:111;1,.,,1 \ \ '' ~"-.. '.\ \ ,\ ' \ " '-'---..:.;:._. -' I'\ \ ' ' "\;;_ " ~ 7 ·-\ ••• '~ ' ' ' ' "-., e4·.. \ ~O \ E11a n11;.i:. . ·• ~ " \', I (' • \ ~ 0. ~.. \ ~ '-'-I S, , • ' ,_ "\\ ', ' o+, . I ,,~ ' 'Q V;:ille) / -.: •• • •• V1;1~ ~~IJ~ --~~ I ~-~\~ ;. J -.. I , -fl , ·, •ol.1, 1.ol ,~~\ - . ' "i;, ""~'"" ~ '---.. , ...._ ' s~ • .:in l•,1;:irco, :l: , ,, \ N FFt._,,,__- :t; ~~ " • ., E 5ccmlld o :' • ,,,, \ ~~ 82I J' \ ; %~----~ I ....._ ' ""'411 , <1· / / I Jul""'-) 1(~11, ' 13: / 1 " "' "- ~111. ''-( ~'I!., '\>\ ·.. \~\<' ~'< ~ '\~ -~ ~1< ~" ~ ,, <f-' '"'-. \,-<' 9, '\~-\ ... \ \ " \ \ "o I ~ 1l ~: ,,\: \, /}~ '\ -..._· \ I -, ~ -,\ \ ..,,.,,..,., • ., 1-~)'' 0.. ~ 1 \ \'. , r~ '-~~~--49, ,/ I • l '~"':-, · I ' \ \ // \ ' \ ~]R;:imon., / / '\ ' i ---I I I I ' i I I \A "--J ~ I I \ I \\~ I / e~, /,,\ ~I\ /c_., .. ,.,. \I• u ''"" L;-•. _,, .m.t. R net,, \"' /R·•···•·· ... " \l /\1~,., f ~ , .: I \ ; ( 1!: \' \ .r I / I \ / ~4A l~ , -~I -1 \ I --;--:tp,t.£ \ , ) I / / \'\ ..--,\ Pins: V.:illcy I : I -_ _.,_ ,. Po·,•,.:a, 7 S~•nls:c ";> ,._,1·u·· ... 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. FAULT CLASSIFICATION COLOR CODE (Indicating Recency of Movement) r====--=-=-==-=::::::::::::::: Late Quaternary fault (during past 700,000 years). I ............ , Historic Fault (last 200 years) Holocene fault (during past 11,700 years) without historic record. j ................ j Quaternary fault (age undifferentiated) _______ .............. , Pre-Quaternary fault (older that 1.6 million years) or fault without recognized Quaternary displacement Excerpt from: DMG OPEN-FILE REPORT 95-03, LANDSLIDE HA ZA RDS IN THE NORTHERN PART OF THE SAN DIEGO METROPOL!TAN AREA, SAN DIEGO COUNTY, DMG OPEN-FILE REPORT 95-03, by the California, California Department of Conservation, Division Of Mines and Geology (1995) \.) -1 .-.. ~ ---~-r-: '·-·: .-:::.:.---:::::-- / o -., . ·. '·~:~...... u,,,1....._:::i-,i,.,_,,.i:;___ ..,,...,...~,;i,,,2;~ . ·; ~ .. •,_,· '\ • I / :-=-~ : ( -·-' '-:-..:.: ' 171>,,oL..--( : ( I ,_ o ·:., -. -~--\ --j //. . ...... . ...... , \ .,· ,I: . . ' . ,,,. \ -( .., ( • :__J _. i ) .._ • ~~ ::,....-... ..... _•~-< ........ ,,---··-:. . -,....,..--· \ l ) --• • -: , ✓-. .-.:;_ _____ _.. ---I -~ .... _"",.... ... ilP!--4....., -~ i •/;_.;I f (.?. . '-··· f-·. t· ___ .,.,. . . •• [ / I i -••••• r:-· • · t:: :f 1:~~ ·:.-··.,L::~~--\-· -( .. -.7""' ~-=-' \-.• --·. i \ .;.-· ··:,;.----, -. • ~-/ ---~ ) ·.-;.: . -·•·-'·-'·'\ i ~· , .· ·)t:• .j.J.. , ,_ Oo . . .\ !_ ',(. • • :· "--. --::.'.·-r'" •• • '·-··-···~ . ' : ; ' RELATIVE LANDSLIDE SUSCEPTIBILITY AREAS 1 2 3-1 I 3-2 4-1 I 4-2 Least Marginally Generally Most Susceptible Susceptible Susceptible Susceptible · ---------------------------------Increasing lands] i de suscepti bi 1i ty-------------------------------> C WI.. ~M~nt~~•JF•F h<G. ~ill andlHQtmdati~nt1Jfflgjn~n.s, Figure No. 6 1, CANTILEVER RETAINING WALL DRAINAGE SYSTEM OPTIONS [I] DETAIL [I] DETAIL 6"MIN . • 3 -'G}: III DETAIL . ',I '47 DETAIL L!J~----- NOTES AND DETAILS GENERAL NOTES: 1) THE NEED FOR WATERPROOFING SHOULD BE EVALUATED BY OTHERS. 2) WATERPROOFING TO BE DESIGNED BY OTHERS 3) EXTEND DRAIN TO SUITABLE DISCHARGE POINT PER CIVIL ENGINEER. 4) DO NOT CONNECT SURFACE DRAINS TO SUBDRAIN SYSTEM. DETAILS: (";'\ 4-INCH PERFORATED PVC PIPE ON TOP OF FOOTING, HOLES \!,; POSITIONED DOWNWARD (SOR 35, SCHEDULE 40, OR EQUIVALENT). 0 ¾ INCH OPEN-GRADED CRUSHED AGGREGATE. 0 GEOFARBRIC WRAPPED COMPLETELY AROUND ROCK. G) PROPERLY COMPACTED BACKFILL SOIL. '5' WALL DRAINAGE PANELS (MIRADRAIN OR EQUIVALENT) \.V PLACED PER MANUFACTURER'S REC'S. C.Wr..llai~CQ~k.. SQil1andiltQ1UldatioB1Bngtne.em © UNDERLAY SUBDRAIN WITH AND CUT FABRIC BACK FROM DRAINAGE PANELS AND WRAP FABRIC AROUND PIPE. 0 COLLECTION DRAIN (fOTAL DRAIN OR EQUIVALENT) LOCATED AT BASE OF WALL DRAINAGE PANEL PER MANUFACTURER'S RECOMMENDATIONS. FIGURE NO. 7 [ 1,, r r { I [, I i. i I I '· i Appendix "A" STANDARD GRADING AND CONSTRUCTION SPECIFICATIONS 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 A. 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. B. All clearing, site preparation, or earthwork performed on the project shall be conducted by the Contractor under the supervision of the Soils Engineer. C. 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. D. 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. E. A final report shall be issued by the Soils Engineer attesting to the Contractor's conformance with these specifications. SITE PREPARATION A. All vegetation and deleterious material shall be disposed of off site. This removal shaII be concluded prior to placing fill. B. 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. C. After the ground surface to receive fill has been cleared, 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 inches 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. D. 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. E. 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. Appendix A Standard Grading and Construction Specifications Page 2 COMPACTED FILLS A. Any material imported or excavated on the property may be utilized in the fill, provided each material has been determined to be suitable by the Soils Engineer. Roots, tree branches, and other matter missed during clearing shall be removed from the fill as directed by the Soils Engineer. B. Rock fragments less than 6 inches in diameter may be utilized in the fill, provided: I. They are not placed in concentrated pockets. 2. There is a sufficient percentage of fine-grained material to surround the rocks. 3. 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 suitable for rock disposal. D. Material that is spongy, subject to decay or otherwise considered unsuitable should not be used in the compacted fill. E. 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. G. If the moisture content or relative density varies from that required by the Soils Engineer, the Contractor should re-work the fill until the Soils Engineer approves it. H. 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-1557-91, 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 except 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 specified in the soil report. K. 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. L. The contractor will be required to 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. \. 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 A. The Engineering Geologist shall inspect all cut slopes at vertical intervals not exceeding 10 feet. B. 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. C. 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 A. Observation of the fill placement shall be provided by the Soils Engineer during the progress of grading. B. 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 CLASSIFICATION CHART SOI L DESC RI PTI ON I . COARSE GRAINED: More than half of material is larger than No. 200 sieve size. GRAVELS: More than half of coarse fraction is larger than No. 4 sieve size but smaller than 3". GROUP SYMBOL CLEAN ORA VELS ORA VELS WITH FINES (Appreciable amount of fines) GW GP GM GC TYPICAL NAMES Well graded gravels, gravel-sand mixtures, little or no fines. Poorly graded gravels, gravel sand mixtures, little or no fines Silty gravels, poorly graded gravel-sand-silt mixtures Clayey gravels, poorly graded gravel sand, clay mixtures. SANDS: More than half of coarse fraction is smaller than No. 4 sieve size CLEAN SANDS SANDS WITH FINES (Appreciable amount of fines SW SP SM SC Well graded sand, gravelly sands, little or no fines Poorly graded sands, gravelly sands, little or no fines Silty sands, poorly graded sand and silty mixtures. Clayey sands, poorly graded sand and clay mixtures II. FINE GRAINED: More than half of material is smaller than No. 200 sieve size SILTS AND CLAYS ML Liquid Limit CL Less than50 OL SILTS AND CLAYS MH Liquid Limit CH greater than 50 OH HJGHL Y ORGANIC SOILS PT Inorganic silts and very fine sands, rock flour, sandy silt -or clayey-silt with slight plasticity. Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays Organic silts and organic silty clays oflow plasticity Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silt Inorganic clays of high plasticity, fat clays. Organic clays of medium to high plasticity. Peat and other highly organic soils.