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HomeMy WebLinkAboutCT 00-22; REDEEMER BY THE SEA LUTHERAN; PRELIM GEOTECH INVESTIGATION PROPOSED;PRELIMINARY GEOTECHNICAL INVESTIGATiON, PROPOSED CHURCH AND RESIDENTIAL DEVELOPMENT REDEEMER-BY-THE-SEA POINSETTIA LANE AND BLACK RAIL ROAD CARLSBAD, CALIFORNIA PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED CHURCH AND RESIDENTIAL DEVELOPMENT REDEEMER-BY-THE-SEA POINSETTIA LANE AND BLACK RAIL ROAD CARLSBAD, CALIFORNIA NOVEMBER 20, 2000 Prepared For: REDEEMER BY THE SEA c/o KEN VOERTMAN 1617 SOUTH PACIFIC STRRET OCEANSIDE, CA 92054 GEX)PACM(2A GEOTECHNICAL CONSULTANTS November 20, 2000 To: Redeemer by the Sea c/o Ken Voertman 1617 South Pacific Street Oceanside, CA 92054 Subject: Preliminary Geotechnical Investigation, Proposed Church and Residential Development, Redeemer by the Sea, Poinsettia Land and Black Rail Road, Carisbad, CA. In accordance with your request and authorization, we have conducted a Geotechnical investigation at the subject site. The accompanying report presents a summary of our Investigation and provides conclusions and recommendations relative to site development. Please do not hesitate to contact this office If you have any questions regarding our report. We appreciate this opportunity to be of service. Respectfully submitted, Geopacifica Inc. ^^imeA *p. 'KttwiifiiM. James F. Knowiton R.C.E. 55754 C.E.G. 1075 3 0 6 0 INDUSTRY ST SUITE 105 OCEANSIDE C A 9 2 0 5 4 TEL: 760.721.5488 FAX: 760.721.5539 TABLE OF CONTENTS Section 1.0 INTRODUCTION 1 2.0 SITE DESCRIPTION AND PROPOSED DEVELOPMENT 1 2.1 Site Description 1 2.2 Proposed Development 1 3.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING .. 4 4.0 GEOTECHNICAL CONDITIONS 4 4.1 Regional Geology 4 4.2 Site Geology 4 4.3 Geologic Structure 5 4.4 Surface and Ground Water 5 5.0 FAULTING AND SEISMICITY 5 5.1 Faulting 5 5.2 Seismicity 6 5.2.1 Lurching and Shallow Ground Rupture 6 5.2.2 Liquefaction and Dynamic Settlement 9 6.0 CONCLUSIONS 9 7.0 RECOMMENDATIONS 10 7.1 Earthwork 10 7.1.1 Treatment of Existing Soils 10 7.1.2 Excavations 11 7.1.3 Trench Excavation and Backflll 11 7.1.4 Fill Placement and Compaction 11 7.1.5 Expansive Soils 11 7.1.6 Slope Stability 12 7.1.7 Surficial Slope Stability 12 7.2 Surface Drainage 12 7.3 Foundation and Slab Design Considerations 12 7.3.1 Foundations - Churcli 13 7.3.2 Foundations - Residential 13 7.3.3 Floor Slabs 15 TABLE OF CONTENTS (Continued) Section 7.3.4 Settlement 16 7.3.5 Moisture Conditioning 16 7.4 Lateral Earth Pressures and Resistance 16 7.5 Retaining Wall Drainage and Backflll 17 7.6 Construction Observation 17 Figures Figure 1 - Site Location Map 3 Figure 2 - Regional Seismicity and Index Map 8 Figure 3 - Boring Location Map Rear of text Tables Table 1 - Seismic Parameters for Active and Potentially Active Faults 7 Appendices Appendix A - References Appendix B - Boring Logs Appendix C - Laboratory Testing Procedures and Test Results Appendix D - General Earthworic and Grading Specifications GEPB^IFTA GEOTECHNICAL CONSULTANTS 1.0 INTRODUCTION This report presents the results of our geotechnical/foundation investigation at the subject site. The purpose ofthe Investigation was to identify and evaluate the Geotechnical conditions present on the site and to provide conclusions and recommendations regarding the proposed development. Our scope of services of the Investigation Included: • Review of available pertinent published and unpublished geologic literature and maps (Appendix A) • Aerial photographic analysis to assess the general geology of the site (Appendix A). • Field reconnaissance of the existing onsite Geotechnical conditions. • Subsurface exploration consisting of the excavation, logging and sampling of nine small diameter borings. The logs of the borings are presented in Appendix B. • Laboratory testing of representative, undisturbed and bulk soil samples obtained from our subsurface exploration program (Appendix C). • Geotechnical analysis of field data and laboratory test results. • Preparation of this report presenting our findings, conclusions and recommendations with respect to the proposed development. 2.0 SITE DESCRIPTION AND PROPOSED DEVELOPMENT 2.1 Site Description The irregulariy shaped subject site is bounded by vacant land to the North and East and the proposed extension of Poinsettia Lane south and Black Rail Road to the west in Carisbad, California (Figure 1). The site Is currently vacant, but has been previously farmed with same grading. Although not encountered during our Investigation, it is possible that buried agricultural fills and debris may be encountered during site development due to the priors use, but was not encountered over most of the site. 2.2 Proposed Development We understand the proposed Redeemer by the Sea Church and proposed Residential deveiopment will include construction of 12 residential pads, several church buildings with parking on the northern portion of the site. Structural Information was not available at the time of this report. However, building loads GE(m:iFKA GEOTECHNICAL CONSULTANTS are assumed typical for these types of structures. Site grading to create the building and parking will include cuts up to depths of approximately +-15 feet. It is anticipated that the proposed cut and fill will encompass the entire site. NORTH 1 Scale 1"=2000' Taken From: Thomas Guide, 2000 Edition LOCATION MAP GEOPACIFICA PROJECT NO. HGURE NO. 1 GEOTECHNICAL CONSULTANTS 3.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING Our subsurface exploratory program consisted of the excavation of 9 small diameter borings drilled to a maximum depth of 30 feet in the proposed building areas. The approximate locations of the borings are shown on the Boring Location Map (Figure 3). The purpose of this program was to evaluate the physical characteristics of the onsite soils pertinent to the site development and check existing ground water levels. The borings were logged and sampled by a geologist from our firm. Bulk and relatively undisturbed samples of the soils were obtained for laboratory testing. Logs of the borings are presented in Appendix B. Logs of the borings are presented in Appendix B. Subsequent to logging and sampling, all borings were backfilled. Laboratory testing was performed on representative samples to evaluate the moisture, density, aind strength characteristics of the subsurface soils. A discussion of the laboratory tests perfomied and a summary ofthe laboratory tests are presented in Appendix C. Moisture and density test results are provided on the boring logs (Appendix B). 4.0 GEOTECHNICAL CONDITIONS 4.1 Regional Geology The subject site is situated in the coastal section of the Peninsular Range Province, a California geomorphic province with a long and active geologic history throughout southern California. Through the last 54 million years, the area known as the San Diego Embayment has undergone several episodes of marine Inundation and subsequent marine regression. This has resulted In a thick sequence of marine and non-marine sediments deposited on rocks of the southem California batholith with relatively minor tectonic uplift of the area. 4.2 Site Geology Based on our subsurface exploration (Appendix B), aerial photographic analysis, and review of pertinent Geotechnical literature and maps (Appendix A), the subject site Is underiain by Pleistocene terrace deposits which are, In turn, underiain by the Tertiary Santiago Fomiation. Minor undocumented fill soils were encountered mantling the terrace deposits and In small canyons on the site. The Pleistocene ten-ace deposits were observed to predominantly consist of red- brown, orange-brown, dry to moist, medium dense to dense, silty, fine-to- medium-grained sand. Based on laboratory testing and visual ciassiflcation, the Pleistocene terrace deposits on the site generally have relatively high shear strength and a very low expansion potential. GEOTECHNICAL CONSULTANTS The Santiago Formation encountered during our investigation primarily consisted of yellow-brown to olive-brown and green-gray, moist, dense to very dense, sllty to slightly clayey, sandy, silt stone and sandstone. Based on visual classification and our experience with similar materials, the typically has relatively high shear strengths and a low to medium expansion potential. Claystones may have a high expansion potential. Fill soils were encountered In Borings B-6 and B-7. These undocumented fill soils were approximately 1-2 feet thick and consisted of brown to red-brown, sllty sand that contained abundant debris. These soils are not considered suitable for the support of structural loads or support of fill In their present condition. 4.3 Geologic Structure Observations made during our subsurface exploration and experience with similar units on nearby sites indicate that the Pleistocene terrace deposits and sandstone units of the Tertiary Santiago Formation are generally massive In this area with no significant geologic structure. Pertinent Geotechnical literature (Appendix A) indicates that the sedimentary soils are generally flat lying to gently dipping. No major folding of the sedimentary units is known or expected to exist at the site. 4.4 Surface and Ground Water No surface water was evident at the time of our investigation. Ground water was not encountered in our borings. Ground water is not anticipated to be a constraint to development. However, seasonal fluctuations In rainfall and irrigation, variations In ground surface and subsurface conditions may significantly affect ground water levels. We recommend that all below grade walls be appropriately waterproofed. 5.0 FAULTING AND SEISMICITY 5.1 Faulting The two principal seismic hazard considerations for developmental projects in southern California are damage resulting from earthquake-Induced shaking and surface rupture along active or potentially active fault traces. The criteria followed In this report, relative to fault activity, are those enacted by the State of California and utilized by the California Division of Mines and Geology In the Alquist-Priolo Act. This act establishes special study zones for active or potentially active faults to assure that unwise urban development does not occur across the traces of active faults. The subject site does not lie within the Alquist-Priolo Special Studies Zone. GEOTECHNICAL CONSULTANTS An active fault is a fault, which has had surface displacement within the last 10,000 to 11,000 years (Holocene Epoch). A fault which exhibits ground rupture within the last 2 million years (Quaternary Period), but does not exhibit direct evidence of offsetting Holocene sediments, is considered potentially active. Any fault shown to be older than the Quaternary period is considered inactive. A review of available geologic literature and aerial photographs pertaining to the subject site (Appendix A) Indicates that there are no known active faults crossing the property. Nor was any indication of faulting during our subsurface Investigation. Figure 2 indicates the location of the site in relationship to known major faults in the southern Califomia region. Included on Figure 2 are the approximate epicentral area and magnitude of earthquakes recorded during the period of 1769 to 1973. The nearest significant active regional faults are the Elsinore Fault Zone, located approximately 19 miles northeast ofthe site and the offshore extension ofthe Rose Canyon Fault Zone, located approximately 5 miles to the southwest according to maps prepared by the Califomia Division of Mines and Geology. 5.2 Seismicity The subject site can be considered to lie within a seismically active region, as can all of southern California. Table 1 Indicates potential seismic events that could be produced by maximum probable earthquakes. A maximum probable earthquake is the maximum expectable earthquake produce from a causative fault furring a 100-year Interval. Site-specific seismic parameters Included in Table 1 are the distances to the causative faults, Richter earthquake magnitudes, expected peak/repeatable high ground accelerations (RHGA), and estimated period and duration of ground shaking. The effect of seismic shaking may be mitigated by adhering to the Uniform Building Code or state-of-the-art seismic design parameters of the Structural Engineers Association of California. A number of secondary effects are produced by seismic shaking. These Include soil liquefaction, seismic settlement, and lurching. 5.2.1 Lurching and Shallow Ground Rupture Soli lurching refers to the rolling motion on the surface by the passage of seismic surface waves causing permanent inelastic deformation of surficial soil. Effects of this nature are likely to be significant where the thickness of soft sediments varies appreciably under a structure. Damage to the proposed development should not be significant because of the relatively dense nature of the onsite soils. Breaking of the ground because of active faulting is not likely to occur on site due to the absence of active faults. Cracking due to shaking from TABLE 1 SEISMIC PARAMETERS FOR ACTIVE AND POTENTIALLY ACTIVE FAULTS REDEEMER BY THE SEA Potential Causative Fault Distance from Fault to Site (Miles) Maximum Credible Earthquake Richter Magnitude MAXIMUM PROBABLE EARTHQUAKE (Functional Basis Earthquake) Potential Causative Fault Distance from Fault to Site (Miles) Maximum Credible Earthquake Richter Magnitude Richter Magnitude Peak Bedrock/ Repeatable Horizontal Ground Acceleration** (Gravity) Predominant Period at Site in Seconds Duration of Strong Shaking at Site in Seconds Elsinore 21 7.6 7.3 0.27 0.35 25+ Rose Canyon (offshore) 5 7.1 6.2 0.49/0.33 0.28 15+ Newport-Ingle-wood (offshore) 18 7.0 6.5 0.17 0.29 15 Coronado Bank (offshore) 20 6.5 6.0 0.11 0.26 8 San Jacinto 45 7.6 7.3 0.11 0.44 15 San Andreas 58 8.5 8.3 0.12 0.61 6+ San Clemente (offshore) 55 7.5 7.0 0.05 0.42 6 La Nacion * 34 6.5 NA — — — • This fault is considered "potentially active" based on our current knowledge of the geologic conditions ofthe San Diego County area. For design purposes, the repeatable horizontal ground acceleration may be taken as 65 percent ofthe peak acceleration for the site within approximately 20 miles of the epicenter (after Ploessel and Slosson 1974). MAJOR EARTHQUAKES AND RECENTLY ACTIVE FAULTS IN THE SOUTHERN CALIFORNiA REGION ACTIVE FAULTS Total length of fault zona that biaaln Holeeana dapoate or Ifiat has had saiMnie activily. EXPLANATION* Fauft Mgmant with Iniptim during an historic aarthquaka. or wtt) asatemle fauft craap. 4 Holocana volcanio acUvfty (Amboy, Plagah, Cam PiMo and Safton Buttes) EARTHQUAKE LOCATIONS Appradmaia aplcantrai area of aarthquaka* that occurrad 1760-1933. Magnftuda* not raeordad by Instrumanta prior to 1906warn astimtfsd trom damaga raporta asalgnad an ifTteosfly V8 (MocBfiad Marcali scala) or graatar; ttiis Is roughly aquivalant to RwMar M 6.0. 31 modafate** aarthquakas, •even major and ona great aarthquak* (1657) were reported in tha 194-year period 1769-1933. Earthquake apicenten siiwa 1933, plotted from jmprovied fcistrumenta. 29 moderate** and three maior aaftltquidcea were recorded in th* 40-year period 1933-1973. See Lamar. Msriiaht Pnctor p^MT haiain far addRhMd axplMialkm of 1^ Coda lacowmandilteni by ft. Stmctural Sr^^ a ncttar Magnkida of 7 3/4 or giealH: a malor aarthquaka 7 to 7 94; a modarato oarttiqu^ «lo 7. Watar Raaowce* BuMIn 116-2 (1964); sdectfans from buHeOns of ttie Qaofagieal md Saisnalogical ScsJ-^^fAmarica: Imn CF^^ ElawantaiySaiamoteqy(19ga>; and ttn Nattonal Alla«.p.6e. « «ni«ncB: irom v.r. REGIONAL SEISMICITY INDEX MAP Project No. ^ - • < •. • Project Name . Redeemerrby-the-Sea Date 11/20/00 Figure No L CM^IFICA GEOTECHNICAL CONSULTANTS near by faults is expected to be minimal and will not affect the structural integrity of the buildings. 5.2.2 Liquefaction and Dynamic Settlement Liquefaction and dynamic settlement of soils can be caused by strong vibratory motion due to earthquakes. Both research and historical data indicate that loose, saturated, granular soils are susceptible to liquefaction and dynamic settlement while the stability of sllty clays and clays is not adversely affected by vibratory motion. Liquefaction is typified by a total loss of shear strength in the affected soil layer, thereby causing the soil to flow as a liquid. This effect may be manifested by excessive settlements and sand boils at the ground surface. Settlement may also occur In loose and cohesion-less material as a result of rapid, seismically induced shaking. The onsite Pleistocene terrace soils and the Santiago Formation are not considered liquefiable due to their density and the absence of a near-surface ground water table. 5.2.3 Seismic Shaking Parameters Based on the site conditions, Chapter 16 of the Uniform Building Code (International Conference of Building Officials, 1997) and Peterson and others (1996), the following seismic parameters are provided. Seismic zone (per Figure 16-2*) 4 Seismic Zone Factor (per Table 16-1*) 0.40 Soil Profile Type (per Table 16-J*) So Seismic Coefficient Ca (per Table 16-Q*) 0.44 NA Seismic Coefficient Cv (per Table 16-R*) 0.64 Nv Near Source Factor NA(per Table 16-S*) 1.0 Near Source Factor Nv (per Table 16-T*) 1.0 Seismic Source Type (per Table 16-U*) B Distance to Seismic Source 5.7 mi. (9.2Km) Upper Bound Earthquake Mw6.9 * Figure and Table references from Chapter 16 of the Uniform Building Code (1997). 6.0 CONCLUSIONS Based on the results of our Geotechnical investigation of the site, it is our opinion that the proposed development is feasible from a Geotechnical standpoint provided the following conclusions and recommendations are incorporated into the project plans and specifications. The following is a summary of the main Geotechnical factors, which may affect development of the site. GE(m:iFK:A GEOTECHNICAL CONSULTANTS a a a Based on laboratory testing and visual classification, the onsite formational soils have relatively high shear strength characteristics and a low expansion potential, both of which are favorable for design of foundations and slabs. Loose fill soils encountered on the site are potentially compressible and are not considered suitable for structural loads or support of fill In their present condition. It Is anticipated that site grading will remove all of these undocumented fill soils. However, some undocumented fills may need to be removed and recompacted. Active faults are not known to exist on or in the immediate vicinity of the site. The maximum anticipated bedrock acceleration on the site is estimated to be approximately 0.49g based on a maximum probable earthquake of Richter Magnitude on the active Rose Canyon fault. Ground water was not encountered. Ground water is not anticipated to have an impact on the proposed development based on the currently proposed grading. Excavation ofthe onsite soils should generally be feasible with conventional, heavy- duty earthwork equipment in good condition. Localized cemented zones may require the use of rock breakers or localized blasting. Based on the success of our drilling program, the extent of such cemented zones should be minimal. Oversize rock materials are unlikely to be generated from excavations In the onsite soils. These materials should be disposed of off site, if encountered 7.0 RECOMMENDATIONS 7.1 Earthwork We anticipate that earthwork at the site will consist of site preparation, excavation and backfill. We recommend that earthwork on site be performed in accordance with the following recommendations and the General Earthwork and Grading Specifications included in Appendix D. In case of conflict, the following recommendations shall supersede those In Appendix D. 7.1.1 Treatment of Existing Soils In areas to receive fill, the existing ground will need to be over-excavated 3 feet and recompacted. Some areas may need deeper removals. Areas of undocumented fill and in canyon, areas may require up to 4-8 feet of recompaction. 10 GECm:iFICA G E O T E C t CONSULTANTS 7.1.2 Excavations Excavation of the onsite soils may be accomplished with conventional, heavy-duty grading equipment. Due to the locally friable nature of the sandy terrace deposits, temporary excavations such as utility trenches with vertical sides may not be stable. Temporary excavations deeper than 5 feet should be shored or laid back to 1:1 (horizontal to vertical) in undisturbed Santiago Formation and Terrace deposits. Shoring recommendations can be provided If needed when final plans are available. All excavations should be made in accordance with OSHA requirements. 7.1.3 Trench Excavation and Backfill Excavation of utility trenches and foundations in the onsite soils appears to be generally feasible with heavy-duty backhoe equipment. The onsite soils may be used as trench backfill provided they are screened of organic matter, debris, and rock fragments greater than 6 inches in maximum dimension. Trench backflll should be compacted in uniform lifts (not exceeding 8 Inches In thickness) by mechanical means to at least 90 percent relative compaction (ASTM Test Method Dl 557-78). 7.1.4 Fill Placement and Compaction The onsite soils are generally suitable for use as compacted fill provided they are free of organic material and debris. All fill soils including retaining wall backfill should be brought to near-optimum moisture conditions and compacted In uniform lifts to at least 90 percent relaitive compaction based on laboratory standard ASTM Test Method Dl 557-78. The optimum lift thickness required to produce a uniformly compacted fill will depend on the type and size of compaction equipment used. In general, fill should be placed In lifts not exceeding 8 inches in thickness. Placement and compaction of fill should be performed in general accordance with local grading ordinances, sound construction practice, and the General Earthwork and Grading Specifications presented in Appendix D. Materials placed within 3 feet of finished grade should be comprised of low expansive soils and contain no rock fragments over 6 inches in maximum dimension. . 7.1.5 Expansive Soils Soils encountered on site should have a very low to medium potential for expansion. Expansive soils are not expected to be a constraint to development. 11 GEOTECHNICAL CONSULTANTS 7.1.6 Slope Stability Our review of the project grading plan Indicates that cut and fill slopes at inclinations of 2:1 (horizontal to vertical) or flatter with an approximate maximum heights of 15 feet respectively are proposed on site. The proposed slopes were analyzed for gross stability utilizing Janbu's analysis method for earth slopes. Slope heights were based on the Figure 3. The strength parameters assumed In our analyses are based on our laboratory test results (Appendix C), our experience with similar units and our professional judgement. 7.1.7 Surficial Slope Stability Our analysis of properiy compacted fill slopes Indicates an adequate factor of safety against surficial failures assuming adequate protection against erosion. However, the outer 2 to 3 feet of fill slopes generally become less dense with time. All slopes should be constructed in accordance with the General Earthwork and Grading specifications (Appendix D) and City of Carisbad grading ordinances. Berms should be provided at the tops of fill slopes, and brow ditches should be constructed at the tops of cut slopes. Drainage should be directed such that surface runoff on slope feces is minimized. Inadvertent oversteepening of cut and fill slopes should be avoided during fine grading and construction. If seepage is encountered in slopes, special drainage features may be recommended by the Geotechnical consultant. Erosion and/or surficial failure potential of fill slopes may be reduced If the following measures are Implemented during design and construction of the slopes. 7.2 Surface Drainage Surface drainage should be controlled at all times. Positive surface drainage should be provided to direct surface water away from the structure, toward the street or suitable drainage facilities. 7.3 Foundation and Slab Design Considerations Foundations and slabs should be designed in accordance with structural considerations and the following recommendations. These recommendations assume the soils encountered within 4 feet of pad grade will have a very low to low potential for expansion. This should be evaluated as necessary during grading. Sub-grade soils should be thoroughly moistened prior to placement of concrete or moisture barriers. The following preliminary foundafion design parameters are based on a proposed lowest finish floor elevation of approximately 327 feet above mean sea level. 12 cjym:iFrA GEOTECHNICAL CONSULTANTS 7.3.1 Foundations - Church Any proposed multi-story structures (church buildings) may be supported by conventional, continuous perimeter, or isolated spread footings extending a minimum of 24 inches beneath the lowest adjacent finished grade. Footings may be designed for a maximum allowable bearing pressure of 3,000 pounds per square foot if founded into competent, formational soils or compacted fill. The allowable pressures may be increased by one-third for loads of short durafion such as wind or seismic forces. Continuous foofings should have a minimum width of 24 inches and 36 inches for Isolated spread foofings. Footings should be reinforced in accordance with the recommendations of the structural engineer. 7.3.2 Foundations - Residential The following foundation construction recommendations are presented as a minimum criteria from a soils engineering standpoint. Our experience in the site vicinity indicates onsite soils will likely vary from low to medium in expansion potenfial (expansion index 21 to 55), based upon which earth material is exposed at finished grades. The following foundation construction recommendafions are presented as a minimum criteria from a soils engineering standpoint. The onsite soils expansion potentials are generally in the low to medium (expansion index 21 to 55). It is anticipated that the finish grade materials will have a low to medium expansion potenfial. However, recommendafions for low and medium, are presented herein for your convenience. Recommendafions by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendafions, should take precedence over the following minimum requirements, Final foundation design will be provided based on the expansion potential of the near surface soils encountered during grading. Low Expansion Potential (Expansion Index 21 to 50) 1. Conventional confinuous footings should be founded at a minimum depth of 18 Inches below the lowest adjacent ground surface for one-story structural loads and 24 inches below the lowest adjacent ground surface for two-story structural loads, interior foofings may be founded at a depth of 18 inches below the lowest adjacent ground surface. Footings for one-story structural loads should have a minimum width of 12 inches, and footings for two-story structural loads should have a minimum width of 15 inches. All footings should have one No. 4 reinforcing bar placed at the top and one No. 4 13 GEOBCIFICA GEOTECHNICAL CONSULTANTS reinforcing bar placed at the bottom of the foofing. Isolated interior or exterior piers and columns should be founded at a minimum depth of 24 Inches below the lowest adjacent ground surface. 2. A grade beam, reinforced as above, and at least 12 inches square, should be provided across the garage entrances. The base of the reinforced grade beam should be at the same elevation as the adjoining footings. 3. Residential concrete slabs, where moisture condensation Is undesirable, should be underiain with a vapor bamer consisting of a minimum of 6 mil polyvinyl chloride or equivalent membrane with all laps sealed. This membrane should be covered above and below with a minimum of 2 inches of sand (total of 4 inches) to aid In uniform curing of the concrete and to protect the membrane forni puncture. 4. Residential concrete slabs should be a minimum of 5 inches thick, and should be reinforced with No. 3 reinforcing bar at 18 Inches on center in both directions. All slab reinforcement should be supported to ensure placement near the vertical midpoint of the concrete. "Hooking" the wire mesh is not considered an acceptable method of positioning the reinforcement. 5. Residential garage slabs should be reinforced as above and poured separately from the stmctural footings and quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. 6. Pre-saturation is not required for these soil conditions. The moisture content of the sub-grade soils should be equal to or greater than optimum moisture In the slab areas. Prior to placing visqueen or reinforcement, soil moisture content should be verified by this office vwthin 72 hours of pouring slabs. Medium Expansion Potential (Expansion Index 51 to 90) 1. Exterior and Interior footings should be founded at a minimum depth of 18 Inches for one-story floor loads, and 30 inches below the lowest adjacent ground surface for two-story floor loads. All footings should be reinforced with two No. 4 reinforcing bars, one placed near the top and one placed near the bottom of the footing. Footing widths should be as indicated in the Unifonn Building Code (Intemational Conference of Building Officials, 1997). 2. A grade beam, reinforced as above, and al least 12 Inches wide should be provided across large (e.g. doorways) entrances. The 14 GEOTECHNICAL CONSULTANTS base of the grade beam should be at the same elevation as the bottom of adjoining footings. Residential concrete slabs, where moisture condensation Is undesirable, should be underlain with a vapor barrier consisting of a minimum of 6 mil polyvinyl chloride or equivalent membrane with all laps sealed. This membrane should be covered above and below with a minimum of 2 Inches of sand (total of 4 Inches) to aid in uniform curing of the concrete and to protect the membrane from puncture. Residential concrete slabs should be a minimum of 5 Inches thick, and should be reinforced with No. 3 reinforcing bar at 18 inches on center in both directions. No. 3 reinforcing bar at 18 inches on center should be doweled behveen the exterior footing and 3 feet into the slab. All slab reinforcement should be supported to ensure piacement near the vertical midpoint of the concrete. "Hooking" the wire mesh is not considered an acceptable method of positioning the reinforcement. Residential garage slabs should be reinforced as above and poured separately from the structural footings and quartered with expansion joints or saw cuts. A positive separation from the footings should be maintained with expansion joint material to permit relative movement. Pre-saturation is recommended for these soil conditions. The moisture content of the sut)-grade soils should be equal to or greater than 120 percent of optimum moisture content to a depth of 18 inches below grade in the slab areas. Prior to placing visqueen or reinforcement, soil pr-saturation should be verified by this office within 72 hours of pouring slabs. 7.3.3 Floor Slabs Floor slabs should be at least 5 Inches in thickness and have a minimum reinforcement consisting of No. 3 rebar spaced 18 inches on center in both directions. Reinforcement should be placed mid-height In the slab. Slabs should be underiain by a 2-Inch layer of clean sand over a 6-mll Visqueen moisture bamer, over a 3-inch sand layer. The potential for slab cracking maybe reduced by careful control of water/cement ratios. The contractor should take appropriate curing precautions during the pouring of concrete in hot weather to minimize cracking of slabs. Cracking can be further controlled by providing saw cuts at column lines. We recommend that a sipsheet (or equivalent) be utilized if grouted tile, marble tile or other crack-sensitive floor covering is 15 GEOTECHNICAL CONSULTANTS planned directly on concrete slabs. All slabs should be designed in accordance with structural considerations. 7.3.4 Settlement The recommended allowable bearing capacity (for isolated spread footings and for a mat foundation) is generally based on a maximum total and differential settlement of 1 inch and % inch, respectively. Actual settlement can be estimated on the basis that settlement is roughly proportional to the net contact bearing pressure and only after column loadings, locations, and footing elevations have b»een designed. Since settlement is a function of footing size and contact bearing pressure, some differential settlement can be expected behween adjacent columns or walls where a large differential loading condition exists. However, for most cases, differential settlements are considered unlikely to exceed Yz Inch. With increased footing depth/width ratios, differential settlements should be less. 7.3.5 Moisture Conditioning The building pads and footing excavafions should be thoroughly moistened prior to placement of concrete or moisture barriers. 7.4 Lateral Earth Pressures and Resistance Embedded structural walls should be designed for lateral earth pressures exerted on them. The magnitude ofthese pressures depends on the amount of defonnation that the walls can yield under load. If the wall can yield enough to mobilize the full shear strength of the soil, it may be designed for "active" pressure. If the wall cannot yield under the applied load, the shear strength of the soil cannot be mobilized and the earth pressure will be higher. Such walls should be designed for "at rest" conditions. If a structure moves toward the soils, the resulting resistance developed by the soil is the "passive" resistance. The recommended equivalent fluid pressure for each case for walls founded above the static ground water table is provided below: Equivalent Fluid Pressure Cantilever wall (yielding) 35 pcf Restrained wall (non-yielding) 50 pcf Passive resistance 350 pcf As an altemate to the above triangular pressure distribution for cantilever walls, the walls may be designed for a rectangular distribution of 25H psf where H is the retained earth height (in feet). 16 GEOB^IFICA GEOTECHNICAL CONSULTANTS The above pressures assume non-expansive, level backfill and free-drainage conditions. Non-expansive backfill should extend horizontally at least 0.5H from the back of the wall where H is the wall height. Retaining walls should be provided with appropriate drainage as shown In Appendix D. Wall footings should be designed in accordance with the previous building foundation recommendations as stated in Section 7.3, and reinforced in accordance with structural considerations. The soil resistance against lateral loading consists of friction of adhesion at the base of foundations and passive resistance against the embedded portion of the structure. Concrete foundations designed using a coefficient of fricfion of 0.35 (total fricfional resistance equals coefficient of friction fimes the dead load). In lateral resistance applications, a passive resistance of 350 psf per foot of depth with a maximum value of 3,500 psf can be used for design. The allowable lateral resistance can be taken as the sum of the fricfional resistance and the passive resistance provided the passive resistance does not exceed two-thirds of the total allowable lateral resistance. The coefficient of friction and passive resistance values can be increased by one-third when considering loads of short duration such as wind or seismic loading. Surface drainage should be controlled at all fimes. The subject structures should have appropriate drainage systems to collect roof runoff. Positive surface drainage should be provided to direct surface water away from the structures toward the street or suitable drainage facilities. Positive drainage may be accomplished by providing a minimum 2 percent gradient from the structures. Planters should not be designed below grade adjacent to structures unless provisions for drainage such as catch basins and pipe drains are made. In general, ponding of water should be avoided adjacent to the structures. 7.5 Retaining Wall Drainage and Backfill Retaining walls should be provided with appropriate drainage as indicated in the typical detail in Appendix D. For the proposed structures, walls should be designed with consideration of hydrostatic pressure and be provided with drainage as indicated in Appendix D. Walls should be provided with appropriate waterproofing in accordance with the recommendations of the design civil engineer or architect. Retaining wall backfill should be compacted to al least 90 percent ofthe soil's maximum dry density based on ASTM Test Method D1557- 78. Backfill should be mechanically compacted In lifts not exceeding 8 inches in thickness. 7.6 Construction Observation The recommendations provided In this report are based on preliminary structural design infonnation for the proposed facilities and subsurface conditions disclosed by widely spaced borings. The interpolated subsurface condifions should be 17 GEOTECHNICAL CONSULTANTS checked in the field during construction by representatives of Geopacifica Inc. Final project drawings should be reviewed by the Geotechnical engineer prior to beginning construction. Construction observation of all onsite excavafions and field density tests of all compacted fill should be performed by the Geotechnical consultant to document construction is performed in accordance with the recommendations of this report. 18 foam ue i.N 13 ! •ET nm SKK asaerricc//MH a oor jOR RKf j« nr jnt HGT JK soarne Mff JR m J>» aaar oe f<e JB mr Me MC «( 4U OFIU. / Y ?ami( -uk V V — — / ^ \«; ' ~^ ' / — .( -v. u f:Mq.srwp oCTMenvr? EMS' osrceeR^ SBS y / \ 1^ — N x^--. -•— Boring Location Map/Geoloqy Mao GEOPACIFICA nCURE NO. 3 GEOTECHNICAL CONSULTANTS APPENDIX A REFERENCES Abbott, P.L., ed., 1985, On the Manner of Deposition of the Eocene Strata in Northern San Diego County; San Diego Association of Geologists Field Trip Guidebook, April 13. Albee, A.L., and Smith, J.L., 1996, Earthquake Characteristics and Fault Activity Southern Califomia in.Lung, R., and Proctor, R., Eds., Engineering Geology in Southem Califomia, Association of Engineering Geologists, Special Publication, dated October. Bam^ws, A.G., 1974, A Review of the Geology and Earthquake History of the Newport-Inglewood Stmctural Zone, Southem Califomia, Califomia Division of Mines and Geology, Special Report 114. Bolt, B.A., 1973, Duration of Strong Ground Motion, Proc. Fifth World Conference on Earthquake Engineering, Rome, Paper N0.292, pp. 1304-1313, dated June. Bonilla, M.J., 1970, Surface Faulting and Related Effects, in_Wiegel, R., Ed., Earthquake Engineering, New Jersey, Prentice-Hall, Inc., pp. 47-74. Eisenberg, L.L, 1983, Pleistocene Terraces and Eocene Geology, Encinitas and Rancho Santa Fe Quadrangles, San Diego County, Califomia, San Diego State University Master's Thesis (Unpublished) p. 386. , 1985, Pleistocene Faults and Marine Terraces, Northem San Diego County in_Abbott, P.L., Editor, On the Manner of Deposition ofthe Eocene Strata in Northem San Diego County, San Diego Association of Geologists, Field Trip Guidebook, pp. 86-91. Greensfelder, R.W., 1974, Maximum Credible Rock Acceleration From Earthquakes in Califomia, Califomia Division of Mines and Geology, Map Sheet 23. Hannan, D.L., 1975, Faulting in the Oceanside, Carlsbad, and Vista Areas. Northem San Diego County, Califomia jn Ross, A. and Dowlen, R.J., eds.. Studies on the Geology of Camp Pendleton and Westem San Diego County, Califomia, San Diego Association of Geologists Field Trip Guidebook, pp. 56-60. Hart, 1985, Fault-Rupture Hazard Zones In Califomia, Alquist-Priolo Special Studies Zones Act of 1972 With Index to Special Study Zones Maps: Department of Conservation, Division of Mines and Geology, Special Publication 42. Jennings, C.W., 1975, Fault Map of Califomia, Scale 1:750,000, Califomia Division of Mines and Geology, Geologic Map NO. 1. Lamar, D.L, Merifield, P.M., and Proctor, R.J., 1973, Earthquake Recurrence Intervals on Major Faults in Southem Califomia, jn Moran, D.E., Slosson, J.E., Stone, R.O., and Yelverton, C.A., Eds., 1973, Geology, Seismicity, and Environmental Impact, Association of Engineering Geologists, Special Publication. CM^IFKA GEOTECHNICAL CONSULTANTS REFERENCES (Continued) Ploessel, M.R., and Slosson, J.E., 1974, Repeatable High Ground Accelerations From Earthquakes-Important Design Criteria, California Geology, V. 27, NO.9. Schnat)el, R., and Seed, H.B., 1973, Accelerations in Rock From Earthquakes in the Westem United States, Bulletin ofthe Seismological Society of America, V. 63, NO. 2, pp. 501-516. Seed, H.B., and Idriss, I.M., 1982, Ground Motions and Soil Liquefaction During Earthquakes, Monogram Series, Earthquake Engineering Research Institute, Berkeley, Califomia. Seed, H.B., and Idriss, L.M., and Kiefer, R.W., 1969, Characteristics of Rock Motions During Earthquakes, Joumal of Soil Mechanics and Foundations Division, ASCE, V.95, NO. SM5, Proc. Paper 6783, pp. 1199-1218. Weber, F. Harold Jr., 1982, Recent Slope Failures, Ancient Landslides and Related Geology of the North-Central Coastal Area, San Diego County, Califomia, Califomia Division of Mines and Geology, Open File Report 82-12, L.A. Wilson, K.L., 1972, Eocene and Related Geology of a Portion of the San Luis Rey and Encinitas Quadrangles, San Diego, Califomia. MAPS Califomia Division of Mines and Geology, 1975, Fault Map of Califomia, Scale 1 "=750,000'. U.S. Geological Sun/ey, 1975, San Luis Rey, 7.5 Minute Series, Scale 1°=2000'. U.S. Geological Survey, 1968, Encinitas, 7.5 Minute Series, Scale 1''=2000'. AERIAL PHOTOGRAPHS Date Source Flight Photo Nos. Scale 1953 USDA AXN-9M 192 and 193 1"=2000' DRILLING COMPANV: Scotts Drilling RK3: Auger DATE ' iQ/3n/nn BORING DIAMETER: 6" P UJ Ul u. 0. Ul a — 0 DRIVE WEIGHT: 1401 bs . If & Q < u. « ^ O ID to z IU o >•« o o DROP: 30" 00 ^ CO dm « ci ELEVATION; 355 BORING NO. 1 SOIL DESCRiPTION 10' EE 16' 20- 25- 30- 26 48 56 58 70 68 108.0 14.0 110.5 16.5 112.5 12.0 Terrace Deposits: Light Brown silty sand. Slightly moist, medi urn dense to dense @14' darker brovyn Santiaqo Formation: Light Green Sandstone,moist h 75 / Total Depth 30' No Water No Caving rd BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-l DRILLING COMPANY: Scotts Drilling RIO: Auqer DATE: 10/30/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401 bs — 0 Ui Ul u. a Ul a < IL. % o oc _J O IB Ul o >« DROP: 30" •u Z K UJ o o s o 0> < ^ J 00 u doo 00 d ELEVATION: 325 BORING NO. SOIL DESCRIPTION Terrace Deposits: Light to Medium brown silty Sand, riioist, dense 40 114.0 11.0 55 Santiaqo Formation: Light green to yellow-brov;n silty to clayey sandstone, moist, very dense IO- IS' 65 Total Depth 16' No Water No Caving 20- as- so- BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-2 DRILLING OOMPANY: Scotts Drilling RIG: Auqer DATE: 10/30/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401 bs DROP: 30" ELEVATION: 350 Ul Ul u. X D. UJ o I— 0 fi. o < u. IE ^ O O I- « z UJ o >« Si Sz H Ul o o 00 .J 00 doo 00 BORING NO. 3 SOIL DESCRIPTION IO- IS- 20' 25- 40 48 50 62 65 Terrace Deposits: Light Brown to Brown Silty Sand, and medium sand, moist, dense to hard 115.2 9.6 113.5 10.0 70 30- Santiago Formation: Light yellow-brown clayey sandstone, moist, dense to hard Total Depth 30' No Water No Caving BORING LOG GEOPACIFICA PROJECT NO. FIGURE NO. B-3 DRILLING COMPANY: Scotts Drilling RIG: Auqer DATE: 10/30/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401bs DROP: 30" ELEVATION: 334 Ul Ul u. a Ul o & o < b. CC _l O ID 0> z Ul o Sl Sz o o z o 00 ZJ 00 «d doo 00 BORING NO. SOIL DESCRIPTION Kl 10' Kl IS' 20- 25-I 30- 28 42 58 56 60 70 107.8 9.0 Terrace Deposits": Brown Silty Sand, Moist,very dense Santiaqo Formation: Light Green to yellow-brown siltstone, moist, very dense Total Depth 30' No Water No Caving BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-4 DRILLING COMPANY: Scotts Drilling RIG: Auger DATE: 10/30/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401bs DROP: 30" ELEVATION: 344 Ul Ul 0. UJ Q & Q S O < u. (C .J a a 00 z ss z Sz Sz O O S U CO < ^ W6 doo o _ 00 C BORiNG NO. SOIL DESCRIPTION IO- IS' I 20' 26- Terrace Deposits: Light Brown Silty Sand. Moist, dense 38 45 60 Total Depth 16' No Water No caving 30'—' «-< 1 1 1 L. E 50RING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-5 DRILLING COMPANY: Scotts Drillinq RIG: Auger DATE: 12/4/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401 bs DROP: 30" ELEVATION: 326 UJ IU 0. UJ o — 0 UJ -I I < oo o < ID 8 Ul _l 0. S < U. " 00 IE _l o a 00 z Ul o ss Sz Sz o O 00 ^ 00 ^ 00 00 w BORING NO. SOIL DESCRIPTION Fill: Dark Brown silty sand.moist, loose Terrace Deposits: Light Brotvn to brown clayey sand, moist, dense 36 60 Santiaqo Formation: Light green and yellow slity to clayey sandstone, moist, very dense IO- IS-60 Total Depth 16' No Water No Caving 20- as- so- BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-6 DRILLING COMPANY: Scotts Drilling RIG: Auger DATE; 12/04/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401 b S DROP; 30" ELEVATION: 225 UJ UJ u. a. UJ o — 0 o. O S 0 < IL. Ul o o -I n > I-« z Ul o >-« ss Sz f= UJ 00 b 5 5 s u 00 00 ^ <Q .J CO O J do» 00 w BORING NO. SOIL DESCRIPTION Fill: Dark Brown silty sand, moist, loose 42 Terrace Deposits: Light brown to brown silty sand, moist, dense 10 < IS' 66 I 56 Santiaqo Formation: Yellow-hrown sandy claystone, Moist, stiff - - yellow-brown sandy siltstone, moist,dense light green clayey sandstone, moist, dense Light reddish brovm claystone, moist, hard 20- as- so- Total Depth 16' No Water No Caving BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-7 DRILLING COMPANY: Scotts Drilling RIG: Auger DATE: 12/04/00 BORING DIAMETER: 6" DRIVE WEIGHT: 1401bs DROP: 30" ELEVATION: 345 p UJ UJ u. z a Ul o a H a o 2 6 < u. « So > 5 QC _l O ID 00 z Ul o >-« ss UJ •_ Sz H UJ Sz o o 00 <^ -I CO dn 00 w BORING NO. 8 SOIL DESCRIPTION 10' 1S- 20- 2S- 30- Terrace Deposits: Light Brown silty Sand, moist. Medium dense 21 39 Total Depth 11' No Water No caving BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-8 DRILLING COMPANY: Scotts Drilling RIG: Auqer DATE: 12/5/00 BORING DIAMETER: 6" P Ul Ul u. X h-Q. Ul o I— 0 DRIVE WEIGHT: 1401bs a K Q. O 3 o < UL oc _J o o >• « z Ul o is DROP: 30" S^ H Ul s g O 5 2 O -1 Ob d» o _ oo w ELEVATION; 377 BORING NO. 9 SOIL DESCRIPTION 10' 15- 20- as- so 45 45 65 71 67 74 Terrace Deposits: Brown silty sand, moist, dense light brown silty sand with gravel, moist, hard 013' brown Total Depth 30' No Water No Caving BORING LOG GEOPACIFICA PROJECT NO. HGURE NO. B-9 GEQB^IFTA GEOTECHNICAL CONSULTANTS APPENDIX C Laboratorv Testing Procedures and Test Results Moisture and Densitv Tests: Moisture content and dry density detenninations were perfonmed on relatively undisturtjed samples obtained from the test borings and/or trenches. The results of these tests are presented in the boring and/or trench logs. Where applicable, only moisture content was determined from "undisturtjed" or disturbed samples. Direct Shear Tests: Direct shear tests were perfomied on selected remolded and/or undisturbed samples which were soaked for a minimum of 24 hours under a surcharge equal to the applied normal force during testing. After transfer of the sample to the shear box, and reloading the sample, pore pressures set up in the sample due to the transfer were allowed to dissipate for a period of approximately 1 hour prior to application of shearing force. The samples were tested under various normal loads, a motor-driven, strain-controlled, direct-shear machine, the motor was stopped and the sample was allowed to "relax" for approximately 15 minutes. The "relaxed" and "peak" shear values were recorded. It is anticipated that, in a majority of samples tested, the 15 minutes relaxing of the sample is sufficient to allow dissipation of pore pressures set up in the samples due to application of shearing force. The relaxed values are therefore judged to be a good estimatbn of effective strength parameters. The test results were plotted on the "Direct Shear Summary". Soluble Sulfates: The soluble sulfate contents of selected samples were detennined by the Califomia Materials Method NO. 417. EXPANSION INDEX TEST SAMPLE SOIL TYPE LOCATION EXPANSION INDEX EXPANSION POTENTIAL B-mv SM 15 VERY LOW 6-2(2)4' SM 18 VERY LOW B-3(a),8' SM 5 VERY LOW MAXIMUM DENSITY TESTS SAMPLE SAMPLE MAXIMUM LOCATION DESCRIPTION DRY DENSITY OPTIMUM MOISTURE CONTENT B-i(2),i' sn .TV SANn 122.5 11.0 6-3(3)8' sn.TYSATsm 116.0 12.0 PH AND MINIMYM RESISTIVITY TESTS SAMPLE LOCATION PH MINIMUM RESISTIVITY B-Kai.r 7.5 7,000 8-3(5)8' 6.9 2,500 SOLUBLE SULFATES SAMPLE LOCATION SULFATE CONTENT (%) POTENTIAL DRYER OF SULFATE ATTACK B-mv <0.015 NEGLIGIBLE 3-2(313' <0.015 NEGLIGBLE LABORATORY TEST RESULTS GEOPACIFICA PROJECT NO. HGURE NO. DIRECT SHEAR TEST SAMPLE LOCATION FRICTION ANGLE COHESION (PSF) B-l@10' B-3@8' B-4(a).]0' 38 36 34 200 250 200 LABORATORY TEST RESULTS GEOPACIFICA PROJECT NO. HGURE NO. GEOTECHNICAL CONSULTANTS APPENDIX D General Earthwork and Grading Specifications 1.0 General intent These specifications are presented as general procedures and recommendafions for grading and earthwork to be utilized in conjunction with the approved grading plans. These general earthwork and grading specifications are a part of the recommendations contained in the Geotechnical report and shall be superseded by the recommendations In the Geotechnical report in the case of conflict. Evaluations performed by the consultant during the course of grading may result in new recommendations, virfilch could supersede these specifications, or the recommendations of the Geotechnical report. It shall t>e the responsibility of the contractor to read and understand these specifications as well as the Geotechnical report and approved grading plans. 2.0 Earthwork Observation and Testing Priorto the commencement of grading, a qualified Geotechnical consultant should be employed for the purpose of observing earthwork procedures and testing the fills for conformance with the recommendations ofthe Geotechnical report and these specifications. It shall be the responsibility of the contractor to assist the consultant and keep him apprised of work schedules and changes, at least 24 hours In advance, so that he may schedule his personnel accordingly. No grading operations should be perfonned without the knowledge of the Geotechnical consultant. The contractor shall not assume that the Geotechnical consultant is aware of all grading operations. It shall be the sole responsibility of the contractor to provide adequate equipment and methods to accomplish the work In accordance with applicable grading codes and agency ordinances, recommendations In the Geotechnical report and the approved grading plans not withstanding the testing and observation of the Geotechnical consultant. If, in the opinion of the consultant, unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting in a quality of wori^ less than recommended in the opinion of the consultant, unsatisfactory conditions, such as unsuitable soil, poor moisture condition, inadequate compaction, adverse weather, etc., are resulting In a quality of work less than recommended in the Geotechnical report and the specifications, the consultant will be empowered to reject the work and recommend that construction be stopped until the conditions are rectified. E p, T E C H N I C A L CONSULTANTS Maximum dry density tests used to evaluate the degree of compaction should be perfonned In general accordance with the latest version of the American Society for Testing and Materials test Method ASTM D1557. 3.0 Preparation of Areas to be Filled 3.1 Clearing and Grubbing: Sufficient brush, vegetation, roots, and all other deleterious material should be removed or properiy disposed of in a method acceptable to the ovmer, design engineer, goveming agencies, and the Geotechnical consultant. The Geotechnical consultant should evaluate the extent of these removals depending on specific site conditions. In general, no more than 1 percent (by volume) of the fill material should consist of these materials should not be allowed. 3.2 Processing: The existing ground which has been evaluated by the Geotechnical consultant to be satisfactory for support of fill, should be scarified to a minimum depth of 6 inches. Existing ground which is not satisfactory should be over-excavated as specified in the following section. Scarification should continue until the soils are broken down and free of large clay lumps or clods and until the woridng surface is reasonably unifonn, flat, and ft-ee of uneven features which would inhibit unifonn compaction. 3.3 Over-excavation: Soft, dry, organic-rich, spongy, highly fractured, or othenwise unsuitable ground, extending to such a depth that surface processing cannot adequately improve the condition, should be over- excavated down to competent ground, as evaluated by the Geotechnical consultant. For purposes of determining quantities of materials over- excavated, a licensed land surveyor/civil engineer should be uitillzed. 3.4 Moisture Conditioning: Over-excavated and processed soils should be watered, dried-back, blended, and/or mixed, as necessary to attain a unifonn moisture content near optimum. 3.5 Recompaction: Over-excavated and processed soils which have been properiy mixed, screened of deleterious material, and moisture- conditioned should be recompacted to a minimum relative compaction of 90 percent or as othenwise recommended by the Geotechnical consultant. 3.6 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical), the ground should be stepped or benched. The lowest bench should be a minimum of 15 feet wide; at least 2 feet into competent material as evaluated by the Geotechnical consultant. Other benches should be excavated Into competent material GEOTECHNICAl CONSULTANTS as evaluated by the Geotechnical consultant. Ground sloping flatter than 5:1 should be benched or othenwise over-excavated when recommended by the Geotechnical consultant. 3.7 Evaluation of Fill Areas: All areas to receive fill, including processed areas, removal areas, and toe-of-fill benches, should be evaluated by the Geotechnical consultant prior to fill placement. 4.0 Fill Material 4.1 General: Material to be placed as fill should be sufficiently free of organic matter and other deleterious substances, and should be evaluated by the Geotechnical consultant prior to placement. Soils of poor gradation, expansion, or strength characteristics should be placed as recommended by the Geotechnical consultant or mixed with other soils to achieve satisfactory fill material. 4.2 Oversize: Oversize material, defined as rock or other in-educible material with a maximum dimension greater than 6 inches, should not be buried or placed in fills, unless the location, materials, and disposal methods are specifically recommended by the Geotechnical consultant. Oversize disposal operations should be such that nesting of oversize material does not occur, and such that the oversize material is completely surrounded by compacted or densified fill. Oversize materials should not be placed within 10 feet vertically of finish grade, within 2 feet of future utilities or underground constmction, or within 15 feet horizontally of slope faces, in accordance with the attached detail. 4.3 Import: ff Importing of fill material is required for grading, the import material should meet the requirements of Section 4.1. Sufficient time should be given to allow the Geotechnical consultant to observe (and test, If necessary) the proposed import materials. 5.0 Fill Piacement and Compaction 5.1 Fill Lifts: Fill material should be placed in areas prepared and previously evaluated to receive fill. In near-horizontal layers approximately 6 inches in compacted thickness. Each layer should be spread evenly and thoroughly mixed to attain unifonnity of material and moisture throughout. 5.2 Moisture Conditioning: Fill soils should be watered, dried-back, blended, and/or mixed, as necessary to attain a unifonn moisture content near optimum. GEOTECHNICAL CONSULTANTS 5.3 Compaction of Fill: After each layer has been evenly spread, moisture- conditioned, and mixed, it should be uniformly compacted to not less than 90 percent of maximum dry density (unless otherwise specified). Compaction equipment should be adequately sized and be either specifically designed for soil compaction or of proven reliability, to efficiently achieve the specified degree and uniformity of compaction. 5.4 Fill Slopes: Compacting of slopes should be accomplished, in additional to normal compacting procedures, by back-rolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation gain, or by other methods producing satisfactory results. At the completion of grading, the relative compaction of the fill out to the slope face should be at least 90 percent. 5.5 Compaction Testing: Field tests of the moisture content and degree of compaction of the fill soils should be perfonned by the Geotechnical consultant. The location and frequency of tests should be at the consultant's discretion based on field conditions encountered. In general, the tests should be taken at approximate intervals of 2 feet In vertical rise and/or 1,000 cubic yards of compacted fill soils. In addition, on slope faces, as a guideline approximately one test should be taken for each 5,000 square feet of slope face and/or each 10 feet of vertical height qf the slope. 6.0 Sub-drain Installation Sub-drain systems If recommended should be installed in areas previously evaluated for suitability by the Geotechnical consultant, to confonn to the approximate alignment and details shovim on the plans or herein. The sub-drain location or materials should not be changed or modified unless recommended by the Geotechnical consultant. The consultant, however, may recommend changes in sub-drain line or grade depending on conditions encountered. All sufc)-drains should be surveyed by a licensed land surveyor/civil engineer for line and grade after installation. Sufficient time shall be allowed for the surveys, prior to commencements of filling over the sub-drains. 7.0 Excavation Excavations and cut slopes should be evaluated by a representative of the Geotechnical consultant (as necessary) during grading. If directed by the Geotechnical consultant, further excavation, over-excavation, and refilling of cut areas and/or remedial grading of cut slopes (i.e., stability fills or slope buttresses) may be recommended. 8.0 GBOB^IFTA Quantity Determination GEOTECHNICAL ONSULTANTS For purposes of determining quantities of materials excavated during grading and/or determining the limits of over-excavation, a licensed land surveyor/civil engineer should be utilized. CANYON SUBDRAIN PROPOSED GRADING COMPACTED FILL BEDROCK -i^e^ UNSIUTABLE BENCH: VERTICAL 4' MIN HORIZONTAL 6' MIN DOZER TRENCH •///^^^jir//m/ CANYON SUBDRAIN DRAINS ALONG CANYON WALLS AS RECOMMENDED BY THE GEOTECHNICAL CONSULTANT. INSTALL AS NEEDED PER BUTTRESS BACKDRAIN DETAIL. GEOFABRIC ALTERNATIVE FILTER MATERIAL 9 CU. FT./FT. DOZER TRENCH ALTERNATE FOR FILLS OF 50' 6" MIN 6'' MIN BACKHOE TRENCH 1" OR 1 1/2" OPEN GRADED ROCK. 9 C.F./LF. NOMINAL 2-3 SEPARATION GEOFABRIC ALTERNATIVE * • A: •.•CL 24" MIN 6" MIN GEOFABRIC: MINIMUM 4% OPEN AREA, EOS = 70 - 140 1*^ MIN OVERLAP NOMINAL 2 - 3" FILTER MATERIAL 9 CU. FT./FT. N9tes; 1. Pipe should be 4" minimum diameter, 6" minimum for runs of 500', 8" minimum for runs of 1000' or greater. 2. Pipe should be Schedule 40 PVC for fills less than 100', Scheduie 80 for fills to 150'. Upstream ends should be capped. 3. Pipe should have 8 unifbrmly spaced 3/8" perforations per foot placed at 90° offset on underside of pipe. Rnai 20 foot of pipe should be nonperforated. 4. Filter material should be California Class 11 F>ermeabie MateriaL 5. Appropriate gradient shouid be provided for drainage; 2% minimum is recommended. 6. For the Geofabric Altemathres and gradients of 4% or greater, pipe may be omitted from the upper 500*. For runs of 500', 1000', and 1500' or greater, 4", 6", and 8" pipe, respecth/ely, should be provkted. 7. Concrete cutoff weli shall be instaiied at end of perforated pipe. STANDARD DETAIL NO. 1 GEOPACinCA PROJECT NO. HGURE NO. FILL OVER NATURAL SLOPE RENCONTOUR, SLOPE TO DRAIN. OR PROVIDE PAVED DRAINAGE SWALES AND DOWN DRAINS BENCH: VERTICAL 4' MIN HORIZONTAL 6' MiN BACKCUT NOT STEEPER THAN 1:1 2' MIN KEY DEPTH AT TOE. TIP KEY V NOMINAL OR 4% INTO SLOPE FILL OVER CUT SLOPE BENCH: VERTICAL 4' MIN HORIZONTAL 6' MIN BACKCUT NOT STEEPER THAN 1:1 Notes: 1. If overfilling and cutting back to grade is adopted, 15' fill width may be reduced to 12' minimum. In no case shouid the fill width be less than 1/2 the height of fill remaining. 2. Badcdrain as recommended by Geotechnical Consultant per Buttress Backdrain Detail. STANDARD DETAIL NO. 2 GEOPACIFICA PROJECTNO. HGURE NO. STABILIZATION FILL 3' MIN CAP (2) 2' MIN 3' MIN BUTTRESS FILL • 15', BACKCUT 1:1 MAX MAINTAIN 15' MIN FILL WIDTH BENCH: VERTICAL 4' MIN HORIZONTAL 6' MIN BACKDRAIN SYSTEM IF RECOMMENDED BY GEOTECHNICAL CONSULTANT 3"^ MIN CAP (2) Dt (4) Dh (5) f^BEDDING PLANES OR OTHER ADVERSE GEOLOGIC CONDmON BACKCUT 1:1 MAX MAINTAIN 15' MIN WIDTH -BENCH: VERTKJAL 4' MIN HORIZONTAL 6' MIN BACKDRAIN SYSTEM PER STANDARD DETAILS Notes: 1. If overfilling and cutting back to grade is adopted, 15" may be reduced to 12*. In no case should the fill width be less than half the fill height remaining. 2. A3' blanket fiii shall be provided above stabiiization and buttress fills. The thickness may be greater as recommended by the Geotechnkxil Consultant 3. W = designed wkfth of key. 4. I>t = designed depth of key at toe. 5. Dh = depth of key at heei; unless otherwise specified, Dh=Dt +1 foot STANDARD DETAIL NO. 3 GEOPACIFICA PROJECT NO. HGURE NO. BUTTRESS BACKDRAIN SYSTEM HORIZONTAL SPACING OF OUTLETS SHOULD BE LIMITED TO ABOUT lOO'^ BLANKET FILL. 3' MIN 1' NOMINAL a' NOMINAL CONVENTIONAL BACKDRAIN SEE DETAILS BELOW FOR H ^ ao' ADDITIONAL UPPER DRAIN MAY BE OMITTED CALIFORNIA CLASS 2 PERMEABLE MATERIAL. 3 CU. FT./FT. V 3' NOMINAL 1 a' MIN -4" MIN GEOFABRIC ALTERNATIVE GEOFABRIC: MINIMUM 4% OPEN AREA EOS = 70-100, 1' MIN OVERLAP Notes: 1. Pipe should be 4" diameter Scheduie 40 PVC. 2. Gradients shouM be 4% or greater. 3. Cap ail upstream ends. 4. Trenches for outlet pipes shouki be backfilled with compacted native soil 5. Backdrain pipe shouid have 8 uniformly spaced perforations per fbot placed 90° offset on underskle of pipe. Outlet pipe shouid be non- perforated. 6. ' For the geofabrk: altemative the backdrain pipe may be omitted provkled at least 20 feet (i.e. 10' each skle of outlet) of perforated pipe is provided to lead into each outlet 7. At each outiet the geofabric shoukl be appropriately overliyiped (1") at cuts in fabric or otherwise sealed or taped around the pipe. 2' MIN NOMINAL CLEAN. OPEN GRADED ROCK. PEA GRAVEL STANDARD DETAIL NO. 4 GEOPACIFICA PROJECT NO. HGURE NO. FUTURE CANYON FILL VIEW ALONG CANYON PROPOSED FUTURE GRADE CURRENT LIMIT OF ENGINEERED FILL. ^^,^p^„.ov «RADE TO PHOVinF DRAINAGE. GSi5^ FUTURE REMOVAL OF UNSUITABLE MATERIAL EXISTING ENGINEERED FILL SURVEY END OF SUBDRAIN VIEW OF CANYON SIDEWALL PROPOSED FUTURE GRADE FUTURE LIMIT OF ENGINEERED FILL FUTURE LIMIT OF ENGINEERED FILL BEDROCK ^^^^^ h* ^FUTURE BENCHING BEDROCK STANDARD DETAIL NO. 5 GEOPACIFICA PROJECTNO. HGURE NO. TRANSITION LOT OVEREXCAVATION CUT LOT PER GRADING PLAN FINISHED GRADE MIN ^BENCH: VERTICAL 4' MIN HORIZONTAL 6' MIN 6" MIN SCARIFICATION IN PLACE AND RECOMPACTION OVEREXCAVATE AND REPLACE AS ENGINEERED FILL CUT-FILL LOT PER GRADING PLAN BENCH: VERTICAL 4' MIN HORIZONTAL 6' MIN 6' MIN SCARIFICATION- IN PLACE AND RECOMPACTION OVEREXCAVATE AND REPLACE AS ENGINEERED FILL Notes: 1. Topsoil,. colluvium, weathered bedrock and otherwise unsuitable materials shoukl be removed to firm natural ground as klentified by the Geotechnical Consultant 2. The minimum depth of overexcavatton shouki be considered subject to review by the Geotechnkal Consuitairt. Steeper transitions may reepjire deeper overexcavatkjn. 3. The iaterai extent of overexcavatnn shoukl be 5' minimum but may inciude the entire lot as recommended by the Geotechnteal Consultant 4. The contractor shoukl notify the Geotechnical Consultant in advance of achieving final grades (Le. wHhin 5") in order to evaluate overexcavation recommendations. Addittonal staking may be requested to aid in the evaluation of overexcavatnns. STANDARD DETAIL NO. 6 GEOPACIFICA PROJECTNO. HGURE NO. ROCK DISPOSAL FINISHED GRADE UTILITY r V MIN^ / CD..^__2oi 5' VERTICAL o STAGGER LOCATIONS OF ROCK WINDROWS NOMINAL SPACING SEPARATION WINDROW SECTION FILL SURFACE DURING GRADING 20' NOMINAL SPACING DOZER V-DITCH OR FILL THOROUGHLY COMPACTED TO A SMOOTH UNYIELDING CONDITION (E.G. BY WHEEL ROLLING) WINDROW PROFILE FILL SURFACE PURWG GRADING CLEAN GRANULAR MATERIAL (SE-> 30} SHOULD BE THOROUGHLY FLOODED TO FILL VOIDS AROUND ROCK COMPACTED FILL 'ROCK SHOULD BE PLACED END TO END. ROCK SHOULD NOT BE NESTED Notes: 1. Fbllowing placement of rock, flooding of granular material and placement of compacted fill adjacent to windrow, each windrow shoukl be thoroughly compacted from the surface. 2. The contractor shoukl provkle pians to the Geotechnnai Consultent prepared by surveys documenting the tocation of buried R>ck. 3. Disposal in streets may be subject to more restrictive requiremente by the goveming authorities. » a STANDARD DETAIL NO. 7 GEOPACIFICA PROJECT NO. HGURE NO. MINOR SLOPE REPAIR MAINTAIN 5' MIN FILL WIDTH ORIGINAL SLOPE SURFACE TO-BE RECONSTRUCTED SLUMP DEBRIS BE REMOVED EARTH BERM 2% BENCH: VERTICAL 2'MIN HORIZONTAL 4^ MIN BACKDRAIN SYSTEM (SEE DETAJLS BELOW). VERTICAL SPACING 8' NOMINAL. OUTLET WITH NON- PERFORATED-PIPE ATrSO' MAX SPACING. PLAN FIRST LEVlEL OF DRAINS TO OUTLET 1-2' ABOVE TOE OF SLOPE. EXCAVATE KEY INTO FIRM UNDERLYING UNAFFECTED MATERIAL' CALIFORNIA CLASS 2 PERMEABLE MATERIAL. 2 CU. FT./FT. MIN SLUMP FAILURE SURFACE OR BASE OF EROSION GEOFABRIC: MIN 4% OPEN AREA, EOS 70-100 1* MIN OVERLAP OPEN GRADED ROCK 3/4 OR 1". 1 CU.FT./Ff. MIM ,4% CONVENTIONAL DRAIN PLACE PIPE ON 4" MIN BED OF RECOMMENDED- PERMEABLE MATERIAL 3" PERFORATED SCH 40 PVC (3/8" PERFORATIONS AT 90» PLACED DOWN) GRADED AT 4%. OUTLET PIPES NON-PERFORATED AND SPACED AT SO' MAX. GEOFABRIC ALTERNATIVE PLACE PIPE ON 2" NOMINAL BED OF RECOMMENDED OPEN GRADED ROCK CALIFORNIA CLASS 2 PERMEABLE MATERIAL. 1 CU.FT./FT. MIN 'DRAIN GUARD' PIPE 3" 'DRAIN GUARD' PIPE OR SIMILAR PLACED ON THIN BED OF SELECT NATIVE OR RECOMMENDED PERMEABLE MATERIAL. GRADE AT 4% TO OUTLET PIPES. NOTE: CAP ALL DRAIN PIPES AT UPSTREAM ENDS STANDARD DETAIL NO. 8 GEOPACIFICA PROJECTNO. HGURE NO. LOT DRAINAGE YARD DRAINS AT 1% OR GREATER. 4" MIN PVC PIPE OR SIMILAR TO SUrrABLE DISPOSAL AREA (E.G. CURB OUTLET) S o i t i Js C ° 1 I _a T- •a o s. •* CM E fll 0 • .a - • i o £ • S-S s ill * «*• O Ol = « 2 iS D) 3 S « ja c "5 ^ >-" o o O IJ: STANDARD DETAIL NO. 9 GEOPACIFICA PROJECTNO. HGURE NO.