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HomeMy WebLinkAboutCT 01-16; CASA LAGUNA; GEOTECHNICAL INVESTIGATION; 2001-12-07ame 17 December 2001 Job No. 0-252-104400 Mr. Michael Roletti RESG, Inc. 31225 La Baya Drive, Suite 103 Westlake Village, CA 91362 RE: Geotechnical Update Letter, Casa Laguna, 670 Laguna Drive, Carlsbad, California, CT 01-16, SDP 01-15. References: 1. AGRA, 2000, Geotechnical Report. Laguna Carlsbad Condominiums, 670 Laguna Drive, Carlsbad, California, Job No. 0-252-104400,dated 24 August 2000 2. Pacific Coast Civil, Inc, 2001, Project Plans, 670 Laguna Drive, Carlsbad, California, dated 25 October 2001, Sheet 1 of 1 Dear Mr. Roletti: In accordance with your request, AMEC Earth & Environmental, Inc. (formerly AGRA) has conducted a geotechnical review of the above referenced plans by Pacific Coast Civil, Inc. for the proposed development at 670 Laguna Drive in Carlsbad, California. We understand that the proposed development has been reduced to 11 units in a total of 6 buildings. Based on the results of our review, it is our opinion that the conclusions and recommendations as presented in our 24 August 2000 report remain valid for the current project design. We appreciate this opportunity to be of service. If you have any questions regarding AMEC's report, please do not hesitate to contact the undersigned. Respectfully submitted, AMEC Earth & Environmental, Inc. Joseph^. Franzone, ROE 39552 /ising Engineering Distribution: (6) Addressee (3) AMEC report dated 24 August 2000 AMEC Earth & Environmental, Inc. 5510 Morehouse Drive San Diego, CA 92121 Tel 1 (858) 458-9044 Fax 1 (858) 458-0943 www.amec.com RECEIVED JAN 0 7 2002 CITY OF CARLSBAD PUNNING DEPT. ame(P GEOTECHNICAL REPORT 670 LAGUNA DRIVE CONDOMINIUMS CARLSBAD, CALIFORNIA Submitted To: RESG, INC. 31225 LA BAYA DRIVE, SUITE 103 WESTLAKE VILLAGE, CALIFORNIA 92008 Submitted By: AGRA EARTH & ENVIRONMENTAL 16760 WEST BERNARDO DRIVE SAN DIEGO, CALIFORNIA 92127-1904 August 24, 2000 Job No. 0-252-104400 amecP August 24, 2000 Job No. 0-252-104400 Mr. Michael Roletti RESG, Inc. 31225 La Baya Drive, Suite 103 Westlake Village, CA 91362 RE: GEOTECHNICAL REPORT LAGUNA CARLSBAD CONDOMINIUMS 670 LAGUNA DRIVE CARLSBAD, CALIFORNIA Dear Mr. Roletti: In accordance with your request and authorization, AGRA Earth 8i Environmental, Inc. (AGRA), an AMEC company, has conducted a geotechnical investigation for the proposed condominium development at 670 Laguna Drive in Carlsbad, Califomia (Figure 1, Site Location Map). Based on the results of AGRA's study, it is our opinion that the development of the site is feasible provided the recommendations presented, herein, are incorporated into the design and construction ofthe proposed improvements. The accompanying report presents a summary of our current findings and provides geotechnical conclusions and recommendations relative to the proposed site development. We appreciate this opportunity to be of service. If you have any questions regarding AGRA's report, please do not hesitate to contact the undersigned. Respectfully submitted, AGRA Earth 8i Environmental, Inc. (Joseph Q'. Franzone, RCE ^ing Engineering iSpavid L. Perry, CEG, 2040 ^ enior Engineering Geologist JGF/TMM/drs Distribution: (6) Addressee \\D8calco\public\0252104400 RESG LasunaDi\0252104400 RESG Laguna DriveCarisbadCondo 08 24 OO.rpt.wpd amecP Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (I) TABLE OF CONTENTS Page 1.0 INTRODUCTION 1 1.1 PURPOSE AND SCOPE 1 1.2 SITE LOCATION AND DESCRIPTION 1 1.3 PROPOSED DEVELOPMENT 3 2.0 SUBSURFACE EXPLORATION AND L^BORATORY TESTING 3 3.0 SUMMARY OF GEOTECHNICAL CONDITIONS 5 3.1 GEOLOGIC SETTING 5 3.2 SITE-SPECIFIC GEOLOGY 5 3.2.1 Undocumented Fill Soils 5 3.2.2 Colluvium 5 3.2.3 Ten-ace Deposits 6 3.2.4 Santiago Fomiation 6 3.3 GROUNDWATER 6 4.0 FAULTING AND SEISMICITY 6 4.1 FAULTING 6 4.2 SEISMICITY 8 4.2.1 Lurching and Shallow Ground Rupture 9 4.2.2 Liquefaction and Dynamic Settlement 9 4.2.3 Tsunamis and Seiches 9 4.2.4 UBC Criteria 9 5.0 CONCLUSIONS 10 6.0 RECOMMENDATIONS 11 6.1 GENERAL EARTHWORK 11 6.1.1 Site Preparation 11 6.1.2 Removals 11 6.1.3 Stnjctural Fills 12 6.2 PRELIMINARY FOUNDATION DESIGN 12 6.2.1 Post-tensioned Foundation Design 12 6.2.2 Conventional Foundation Design 14 6.2.3 Moisture Conditioning 15 6.3 SETTLEMENT 16 6.4 U^TERAL EARTH PRESSURES AND RETAINING WALL DESIGN CONSIDERATIONS 16 6.5 PRELIMINARY PAVEMENT DESIGN 17 ame Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (ii) TABLE OF CONTENTS (continued) Page 6.6 CONTROL OF SURFACE WATER AND DRAINAGE CONTROL 19 6.7 SOIL CORROSIVITY 19 6.8 FLATWORK RECOMMENDATIONS 20 7.0 CONSTRUCTION OBSERVATION, LIMITATIONS, AND PLAN REVIEW 20 8.0 REFERENCES 21 TABLES Table 1 - Seismic Parameters for Active Faults 8 FIGURES Figure 1 - Vicinity Map 2 Figure 2 - Boring Location Map 4 Figure 3 - Fault Map 7 APPENDICES Appendix A Boring Logs Appendix B Laboratory Data Analysis Appendix C General Earthwork and Grading Specifications for Rough Grading ame Mr. Michael Roletti RESG. Inc. August 24. 2000 Project No. 0-252-104400 Page (1) 1.0 INTRODUCTION 1.1 PURPOSE AND SCOPE This report presents the results of our geotechnical study forthe proposed residential development of the approximate 1%-acre property at 670 Laguna Drive in Carisbad, Califomia (Figure 1). The purpose of our study was to evaluate the existing significant geotechnical conditions present at the site and to provide preliminary conclusions and geotechnical recommendations relative to the proposed development. Our scope of services included: • Review of available pertinent, reference documents regarding the geotechnical conditions at the site. • A geologic/geotechnical reconnaissance of the site. • Excavation of five exploratory borings across the site. (Underground Service Alert was contacted prior to drilling.) • Geologic logging of the borings. • Obtained representative soil samples during drilling for laboratory testing and analysis purposes, as appropriate. • Geotechnical analysis of data obtained. • Preparation of this report addressing the geotechnical conditions at the site with respect to the proposed development. 1.2 SITE LOCATION AND DESCRIPTION The project site, 670 Laguna Drive, is located northwest of the intersection of Laguna Drive and Madison Street in Carisbad, California (Figure 1). The site is composed of Lots 8 and 9 of Block 223, Map 2492, Buena Vista Gardens. Currently, a single-family residence occupies the property and is located in the southwestem portion of the property. A wooden fence approximately delineates the property boundary in the backyard area. A chain fence with a locked gate divides the front yard from the backyard. The surface of the site is relatively level and partially covered with dry grasses and scattered shrubs and trees. The site surface elevation is about 40 feet above mean sea level (MSL). Mr. Michael Roletti RESG, Inc. Job No. 0-252-104400 August 30. 2000 Page (2) 0 mi 0.3 mi 0.6 mi 1.2 mi Approximate Graphic Scale 1 in = 0.3 mi Approx. North Reference: Streets98. Microsoft Expedia. Version 6.0 LAGUNA CARLSBAD CONDOMINIUMS 670 Laguna Drive CARLSBAD. CALIFORNIA Figure 1 - Vicinity Map AGRA Engineering Global Solutions AlF —stiff 1—xrmj:— 8/00 0-252-104400 ame Mr. Michael Roletti RESG, Inc. August 24. 2000 Project No. 0-252-104400 Page (3) 1.3 PROPOSED DEVELOPMENT It is our understanding that the proposed development will include minor grading and the construction of a 24-unit condominium complex. Condominium units are planned to be 2-story structures. Associated concrete flatwori<, asphalt concrete roadways/pari<ing, and landscaping are also planned. Preliminary foundation design or structural loads were not provided prior to preparation of this report. 2.0 SUBSURFACE EXPLORATION AND LABORATORY TESTING Subsurface exploration was performed on August 8,2000. Five exploratory borings were drilled with a hollow stem auger drill rig across the site. The approximate locations of the borings are shown on Figure 2. The borings were drilled to approximately 21 feet below the ground surface. The purpose of the exploratory borings was to evaluate the physical characteristics and engineering properties of the on-site soils pertinent to the proposed development. An AGRA engineer logged the exploratory borings. Representative ring and bulk samples were obtained for laboratory testing. Relatively undisturbed (ring) samples were obtained using a 2.5- inch I.D. sampler driven by a 140-pound hammer falling 30 inches. SPT samples were also obtained. Bulk samples were obtained from drill cuttings. After logging and sampling, the excavations were backfilled with the drill cuttings. Laboratory testing was performed on ring samples from the borings to evaluate the in-situ moisture and density, grain-size distribution, shear strength, potential consolidation, R-value, expansion potential and corrosivity characteristics ofthe subsurface soils. Conrosivity testing included pH and minimum resistivity, sulfate content, and chloride content testing. A discussion of the laboratory tests performed and a summary of the laboratory test results are presented in Appendix B. In-situ moisture and density test results performed on ring samples are provided on the boring logs in Appendix A. Mr. Michael Roletti RESG, Inc. Job No. 0-252-104400 August 30, 2000 Page (4) B-5 TD=2r B-4~~' TD=21.5'i Approximate Location of Existing Residence B-3 TD=21' B-2 TD=2r| ^XXXXXXXX 1 TD=21' I LAGUNA DRIVE EXPLANATION B-5 ^ APPROXIMATE •Qr BORING LOCATION TD=21' with TOTAL DEPTH WOODEN FENCE CHAIN LINK FENCE XXXXX GATE DRAWING NOT TO SCALE N t LAGUNA CARLSBAD CONDOMINIUMS 670 LAGUNA DRIVE CARLSBAD, CALIFORNIA FIGURE 2 - BORING LOCATION MAP AGRA Earth & Environmental nuFT iVPROVED Joa HO. TMM 8/00 0-2S2-104400 ame Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (5) 3.0 SUMMARY OF GEOTECHNICAL CONDITIONS 3.1 GEOLOGIC SETTING The project site is situated on the coastal plain of the Peninsular Range Physiographic Province. The project vicinity area is underiain by sedimentary strata of Late Cretaceous, Tertiary and Quatemary age resting unconformably on a basement rock of the Southern Califomia batholith. Tertiary, predominantly marine, sediments are capped by Quatemary marine and non-marine sediments deposited on a series of coastal terraces forming a belt along the modem shoreline. Each marine tenrace was wave-cut during a Pleistocene sea transgression (sea-level high stand), followed by deposition of sediments during the sea regression, and has undergone tectonical uplift. Four ten^aces are recognized in the site vicinity area, with the oldest ten-ace occupying the highest elevation that, reportedly, is con-elated with the Linda Vista Formation. The project site is located on the youngest ten-ace (at the lowest elevation). The tenrace surface is dissected by Buena Vista Creek drainage north of the site. Quatemary terrace deposits underiying the project site consist of reddish brown, pooriy bedded, poorly to moderately indurated sandstone, siltstone and conglomerate (Tan and Kennedy, 1996). These deposits unconformably overiie the Eocene-aged Santiago Fomiation, represented by light- colored sandstone interiayered with siltstone and claystone. 3.2 SITE-SPECIFIC GEOLOGY Based on our subsurface exploration and review of pertinent geologic literature and maps, the site is underiain by undocumented fill, colluvium, terrace deposits, and the Santiago Formation. A brief description of the geologic units encountered on the site is presented below. 3.2.1 Undocumented Fill Soils The thickness of the fill soils appears to be up to 4 feet, as encountered in our borings. The fill soils were generally composed of brown, loose, silty sand. Expansion testing on this unit indicates a very low expansion potential (Appendix B). 3.2.2 Colluvium Colluvium was encountered underiying the fill at Borings B-1 to B-4 and at the existing ground surface at Boring B-5. The colluvium was encountered to depths of 7 to 8% feet below the ground surface in Borings B-1, B-3, B-4, and B-5 and to a depth of approximately 4 feet in Boring B-2. This unit generally consists of medium stiff to stiff sandy clay. Based on laboratory testing on one sample of the colluvium, this unit was found to have a high expansion potential (Appendix B). ame Mr. Michael Roletti RESG. Inc. August 24. 2000 Project No. 0-252-104400 Page (6) 3.2.3 Terrace Deposits Terrace deposits were encountered underiying the colluvium. The tenrace deposits were encountered to a depth of 8 to 11 feet below the ground surface. This unit generally consists of medium dense clayey sand. 3.2.4 Santiago Formation The Santiago Fonmation was encountered underiying the terrace deposits and was encountered to the maximum depth of each boring, or 20 to 21 feet. This unit, as encountered, consists of weakly to moderately cemented clayey sandstone. This unit is not anticipated to be encountered during grading. 3.3 GROUNDWATER During our investigation, groundwater was encountered at depths ranging from 15 to 1814 feet below the existing ground surface. It is important to recognize that groundwater levels can fluctuate due to rainfall, irrigation and surface run-off. 4.0 FAULTING AND SEISMICITY 4.1 FAULTING Our discussion of faults on the site is prefaced with a discussion of Califomia legislation and policies conceming the classification and land-use criteria associated with faults. By definition of the Califomia Mining and Geology Board, an "active" fault is a fault that has had surface displacement within Hoiocene time (about the last 11,000 years). The state geologist has defined a "potentially active" fault as any fault considered to have been active during Quaternary time (last 1,600,000 years). This definition is used in delineating Earthquake Fault Zones as mandated by the Alquist-Priolo Geologic Hazards Zones Act of 1972 and as subsequentiy revised in 1975, 1985, 1990, 1992, and 1994. The intent of this act is to assure that unwise urtjan development and certain habitable structures do not occur across the traces of active faults. The subject site is not included within any Earthquake Fault Zones as established by the State Geologist around known active faults. Our review of published and in-house geologic literature (Section 8.0) and maps indicates that there are no known major or active faults on or in the immediate vicinity of the site. The nearest active regional faults are the Newport-Inglewood - Rose Canyon Fault Zone, Coronado Bank Fault and Whittier - Elsinore Fault Zone located approximately 4, 21, and 24 miles from the site, respectively (see Figure 3 for regional tectonic framework). Mr. Michael Roletti RESG, Inc. Job No. 0-252-104400 August 30, 2000 Page (7) ame Mr. Michael Roletti RESG, Inc. Project No. 0-252-104400 August 24, 2000 Page (8) 4.2 SEISMICITY The site can be considered to lie within a seismically active region, as can all of Southem Califomia. Table 1 (below) identifies potential seismic events that could be produced by the maximum probable and credible earthquake events. A maximum probable earthquake is the largest earthquake expected on a given fault during a specified period of time. The Califomia Division of Mines and Geology cunrentiy uses a 63% probability of being exceeded in a 100-year period as the criterion for establishing the maximum probable earthquakefor a particular fault. The maximum credible earthquake is the largest earthquake that might be expected to occur based on the tectonic frameworic of the region as it is cun-ently understood. Site-specific seismic parameters included in Table 1 are the distances to the causative faults, earthquake magnitudes, and expected ground accelerations. TABLE i Seismic Parameters For Active Faults Fault Zone (Seismic Source) Distance to Site (Miles) Maximum Credible Earthquake Maximum Probable Earthquake Design Earthquake (g) Fault Zone (Seismic Source) Distance to Site (Miles) Moment Magnitude Peak Horizontal Ground Acceleration (g) Moment Magnitude Peak Horizontal Ground Acceleration (g) Design Earthquake (g) Rose Canyon 4 7.0 0.48 6.5 0.31 0.28 Coronado Bank 21 7.5 0.18 6.7 0.09 0.28 Elsinore 24 7.5 0.15 6.6 0.07 0.28 As indicated in Table 1, the Rose Canyon Fault is the nearest to the site and is considered to be the source ofthe strongest potential ground shaking. The maximum credible earthquake from the Rose Canyon has 7.0 moment magnitude, generating peak horizontal bedrock accelerations of 0.48g at the project site. The maximum probable earthquake from the Rose Canyon Zone is considered to have a magnitude of 6.5, generating a peak horizontal bedrock acceleration of 0.31 g at the project site. Earthquakes on other faults also could affect the site, but the estimated earthquake effects from other faults are predicted to be less severe than those which could be generated by the Rose Canyon Fault. ame Mr. Michael Roletti RESG. Inc. August 24. 2000 Project No. 0-252-104400 Page (9) From a probabilistic standpoint, the design ground motion is defined as the ground motion having a 10 percent probability of being exceeded in 50 years. This ground motion is referred to as the design ground motion (UBC, 1997). The design ground motion atthe site is predicted to be 0.28g. The effect of seismic shaking may be mitigated by adhering to the Uniform Building Code and state-of-the-art seismic design parameters of the Structural Engineers Association of Califomia (see Section 4.2.5). Secondary effects that can be associated with severe ground shaking following a relatively large earthquake include ground lurching and shallow ground mpture, soil liquefaction and dynamic settlement, seiches and tsunamis. These secondary effects of seismic shaking are discussed in the following sections. 4.2.1 Lurching and Shallow Ground Rupture Soil lurching refers to the rolling motion on the ground surface by the passage of seismic surface waves. Effects of this nature are likely to be significant where the thickness of soft sediments vary appreciably under structures. Damage to the proposed development should not be significant since a relatively large differential colluvium/fill thickness does not exist below the site. 4.2.2 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 soils with a clay content of 15 percent or more and nonsensitive clays are 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. Due to the relatively dense and clayey nature of the colluvial soils and formational material, the potential for liquefaction is considered to be very low at the site. 4.2.3 Tsunamis and Seiches Based on the elevation of the site with respect to sea level, the distance between the site and large, open bodies of water, and barriers behveen the site and the open ocean, the possibility of seiches and/or tsunamis is considered to be low. 4.2.4 UBC Criteria Geotechnical parameters for design to resist seismic forces in accordance with Intemational Council of Building Officials procedures (UBC, 1997) are contained in Table 2. Mr. Michael Roletti RESG, Inc. Project No. 0-252-104400 ame August 24, 2000 Page (10) TABLE 2 UBC Seismic Design Parameters UBC Table Coefficient/Factor Value 16-1 Seismic Zone Factor Z Zone 4; Z = 0.40 16-J Soil Profile Type Sc 16-Q Seismic Coefficient C. 0.40/V. 16-R Seismic Coefficient Cy 0.56/Vy 16-S Near-Source Factor N, 1.0 16-T Near-Source Factor 1.15 16-U Seismic Source Type Type B M>= 6.5; SR<2 5.0 CONCLUSIONS Based on the results of our preliminary geotechnical evaluation 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 geotechnical factors that may affect development of the site. • Based on our subsurface exploration and laboratory testing, the colluvial soils are generally considered to have a high expansion potential (Appendix B) while the overiying fill soils have a very low expansion potential. Removal and recompaction is anticipated to provide a medium expansion potential belowthe structures. Accordingly, we recommend the use of reinforced conventional foundations or post-tension slabs. • Based on subsurface exploration of the fill and colluvial soils present on the site, we anticipate that these materials should be generally rippable with conventional medium-duty earthwork equipment. • Laboratory test results indicate the soils present on the site have a negligible potential for sulfate attack on concrete. However, these soils are also considered to be severely corrosive to ferrous metals. The design earthquake, having a 10 percent probability of being exceeded in 50 years, is expected to produce a peak ground surface acceleration at the site of 0.28g. ame Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (11) • Groundwater was encountered at a depth of 15 to 1834 feet below the existing ground surface during our subsurface exploration. Groundwater is not anticipated to be encountered during site grading and construction. Seepage should be anticipated after episodes of precipitation or near areas of irngation. Groundwater is not expected to significantly impact the at-grade proposed development provided the recommendations regarding drainage outlined in this report are implemented. • Based on our analysis, there is a very low potential for liquefaction of the on-site soils. 6.0 RECOMMENDATIONS 6.1 GENERAL EARTHWORK Earthwork should be performed in accordance with the General Earthwori< and Grading Specifications in Appendix C and the following recommendations. The recommendations contained in Appendix C are general grading specifications provided for typical grading project and may not be strictly applicable to this project. The specific recommendations contained in the text of this report supersede the general recommendations in Appendix C. The contract with the earthwork contractor should be worded such that it is the responsibility of the contractor to place the fill properiy and in accordance with the recommendations of this report and the specification in Appendix C, not withstanding the testing and observation of the geotechnical consultant. 6.1.1 Site Preparation Following demolition ofthe structures that are to be removed, the surface ofthe site should be stripped to remove existing vegetation, debris, other deleterious materials and pavements. Existing irrigation, drainage and utility lines, or other existing subsurface structures which are not utilized, should be removed, destroyed or abandoned in compliance with current regulations. If a pipe which extends off the property is to be abandoned, it should be properiy capped at the project boundary. Holes resulting from removal of buried obstructions such as foundations or below-grade structures that extend below finished site grades should be filled with properiy compacted soil under the observation and testing of the geotechnical engineer. Mixing of different types of on-site soils or mixing of soil and lime (Section 6.2.2) to reduce expansion potential should be performed by appropriate equipment that provides thorough mixing without clay clumps. Mixing should be performed under the observation and testing of the geotechnical consultant. 6.1.2 Removals Based on laboratory testing, the colluvial soils have a high expansion potential and the fill soils have a very low expansion potential. "Mixing" of these soils is recommended to create a fill blanket of moderate expansion potential (less than 90 per UBC 18-2). Import soil, if ame Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (12) necessary, should be granular soil with an expansion index (El) less than 50. The depth of recommended removals across the site is a minimum depth of 4 feet below the proposed pavement or slab subgrade elevation. Removals should extend at least 5 feet beyond the perimeter of the foundation footprints. All excavation/removal bottoms should expose firm and competent material and all bottoms should be observed by the geotechnical engineer. Mixing of on-site soil (to a depth of 3 feet below structures and 2 feet below the flatNOtk and pavement) with 4% quick lime is recommended for conventional foundations (Section 6.2.2). 6.1.3 Structural Fills The on-site surficial soils are generally suitable for use as compacted fill. Import soils should be tested by the geotechnical consultant prior to site delivery. Fills placed within 4 feet of finish pad grade should consist of soils with an expansion potential less than 90 based on UBC Standardi8-2 and with a maximum size less than 8 inches. Asphalt concrete and concrete should not be placed below the water table or within 5 feet of pad grade. Asphalt and concrete should be broken up to a maximum size of 8 inches in structural fills. The area to receive fill should be scarified to a minimum depth of 6 inches, brought to a moisture content of 3% above optimum moisture content, and recompacted to at least 90 percent relative compaction (based on Modified Proctor, ASTM D1557). The optimum lift thickness to produce a uniformly compacted fill will depend on the type and size of compaction equipment used. In general, fill should be placed in uniform lifts not exceeding 8 inches in loose thickness. Fill soils should be placed at a minimum of 90 percent relative compaction (based on ASTM D1557) and moisture conditioned to 3 percent above optimum moisture content. Placement and compaction of fill should be performed in accordance with the local grading ordinance under the observation and testing of the geotechnical consultant. 6.2 PRELIMINARY FOUNDATION DESIGN We anticipate that moderately expansive soils will be at the proposed bottom of footing elevation. AGRA recommends that either a conventional or a post-tension foundation system be used to support the proposed structures. Separate foundation design parameters are presented in this section for both options. 6.2.1 Post-tensioned Foundation Design We understand the proposed residential structures will be one- to hvo-story, of wood-frame construction. Based on the moderately expansive soil anticipated at the proposed grade, we recommend a post-tensioned slab-on-grade floor system to provide a better perfonning foundation system to reduce the potential for expansive-soil related distress. Foundations and slabs should be designed by a stmctural engineer in accordance with stmctural ame Mr. Michael Roletti RESG, Inc. Project No. 0-252-104400 August 24, 2000 Page (13) considerations and the following recommendations. These recommendations assume that the soils in the upper 4 feet of finish grade will have a moderate potential for expansion (an expansion index less than 90 per UBC Standard 18-2). The actual expansion potential of the finish grade soils ofthe building pads should be evaluated upon completion ofthe fine- grading operations so that final geotechnical design recommendations can be made. We recommend that post-tensioned slabs be designed in accordance with the following design parameters presented in Table 3 and the criteria of the 1997 edition of the Uniform Building Code (ICBO, 1997). TABLE 3 Post-tensioned Slab Design Recommendations Expansion Index (UBC 18-I-B) Design Criteria Moderate (50 to 90) Edge Moisture Variation, e^ Center Lift: Edge Lift 5.5 feet 2.5 feet Differential Swell. y„ Center Lift: Edge Lift: 3.0 inches 1.0 inches Minimum Perimeter Footing Embedment 18 inches The post-tensioned slabs should be designed in accordance with the recommendations of the stmctural engineer. Slabs should be underiain by a 2-inch layer of clean sand (sand equivalent greater than 30) to aid in concrete curing, which is underiain by a 10-mil (or heavier) moisture banier, which is in tum underiain by 2 inches of clean sand to act as a capillary break. All penetrations through the moisture banier and laps should be sealed. Slab subgrade soils should be presoaked in accordance with the recommendations presented in Section 6.2.3. Our experience indicates that use of reinforcement in slabs and foundations can generally reduce the potential for drying and shrinkage cracking. However, some cracking should be expected as the concrete cures. Minor cracking is considered normal; however, it is often aggravated by a high water/cement ratio, high concrete temperature at the time of placement, small nominal aggregate size, and rapid moisture loss due to hot, dry, and/or windy weather conditions during placement and curing. Cracking due to temperature and moisture fluctuations can also be expected. The use of low slump concrete (not exceeding 4 inches at the time of placement) can reduce the potential for shrinkage cracking. Moisture barriers can retard, but not eliminate vapor movement from the underiying soils up through the slab. We recommend that the floor-covering contractor test the moisture ame(P Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (14) vapor flux rate prior to attempting application of moisture-sensitive flooring. "Breathable" floor covering or special slab sealants should be considered if the vapor flux rates are high. Floor covering manufacturers should be consulted for specific recommendations. To reduce the potential for future cosmetic distress due to concrete shrinkage cracks and minor soil movement, AGRA recommends that any proposed inflexible floor coverings, such as ceramic tile or decorative stone, be installed on a 1 %-inch thick, wire-reinforced mortar bed over a cleavage membrane, as recommended by the Ceramic Tile Institute. The purpose of the mortar bed and cleavage membrane is to allow minor slab movement under an inflexible floor covering without significant impact to the covering. Altemate means of providing the same level of protection may also be considered if recommended by a qualified tile contractor. Flexible joint material should be used where crack-sensitive flooring overiies concrete joints. 6.2.2 Conventional Foundation Design We anticipate that soils of moderate expansion potential will exist after site grading. Subgrade should be treated with lime (see Section 6.1.2) for this option. Footings bearing in properiy compacted, stmctural fill should have a minimum depth of 18 inches belowthe lowest adjacent compacted soil grade. At a depth of 18 inches, footings may be designed using an allowable soil-bearing value of 2.000 pounds per square foot (psf). This value may be increased by one-third for loads of short duration including wind or seismic forces. Continuous footings should be reinforced with a minimum reinforcement of four No. 4 rebars, two near the top and two near the bottom of the footing. Isolated-spread footings should be reinforced with a minimum reinforcement of four No. 4 rebars, hvo top and two bottom, per foot of width and depth. Isolated-spread footings shall have a minimum base dimension no less than 24 inches. Where the foundation is within 3 feet (horizontally) of adjacent drainage swales, the adjacent footing should be embedded a minimum depth of 12 inches below the swale flow line. Conventional foundations provide a less rigid slab system to reduce the potential for minor slab cracking. All floor slabs should have a minimum thickness of 4 inches. Minimum reinforcement should consist of No. 3 rebars at 18 inches on center (each way) or No. 4 rebars at 24 inches on center (each way). We emphasize that it is the responsibility of the contractor to ensure that the slab reinforcement is placed at slab mid-height. Slabs should be underiain by a 2-inch layer of clean sand (sand equivalent greater than 30) to aid in concrete curing, which is underiain by a 10-mil (or heavier) moisture barrier, which is in tum underiain by 2 inches of clean sand to act as a capillary break. All penetrations through the moisture barrier and laps should be sealed. The subgrade soil should be presoaked in accordance with the recommendations of Section 6.2.3. Mr. Michael Roletti RESG, Inc. Project No. 0-252-104400 amecP August 24. 2000 Page (15) Our experience indicates that use of reinforcement in slabs and foundations can generally reduce the potential for drying and shrinkage cracking. However, some cracking should be expected as the concrete cures. Minor cracking is considered normal; however, it is often aggravated by a high water/cement ratio, high concrete temperature at the time of placement, small nominal aggregate size, and rapid moisture loss due to hot, dry, and/or windy weather conditions during placement and curing. Cracking due to temperature and moisture fluctuations can also be expected. The use of low slump concrete (not exceeding 4 inches at the time of placement) can reduce the potential for shrinkage cracking. Moisture barriers can retard, but not eliminate vapor movement from the underiying soils up through the slab. We recommend that the floor-covering contractor test the moisture vapor flux rate prior to attempting application of moisture-sensitive flooring. "Breathable" floor covering or special slab sealants should be considered if the vapor flux rates are high. Floor covering manufacturers should be consulted for specific recommendations. To reduce the potential for future cosmetic distress due to concrete shrinkage cracks and minor soil movement, AGRA recommends that any proposed inflexible floor coverings, such as ceramic tile or decorative stone, be installed on a 1 %-inch thick, wire-reinforced mortar bed over a cleavage membrane, as recommended by the Ceramic Tile Institute. The purpose of the mortar bed and cleavage membrane is to allow minor slab movement under an inflexible floor covering without significant impact to the covering. Altemate means of providing the same level of protection may also be considered if recommended by a qualified tile contractor. Flexible joint material should be used where crack-sensitive flooring overiies concrete joints 6.2.3 Moisture Conditioning The slab subgrade soils underlying the post-tensioned foundation systems should be presoaked in accordance with the recommendations presented in Table 4 prior to placement of the moisture barrier and slab concrete. Lime-treatment should be perfomied below conventional foundations. The subgrade soil moisture content should be checked by a representative of the geotechnical consultant prior to slab constmction. TABLE 4 Minimum Presaturation Recommendations for Foundation Subgrade Soils Expansion Potential (UBC 18-I-B) Presoaking Recommendations Very Low to Low (or Lime-Treated) Near-optimum moisture content to a depth of 6 inches Medium Minimum of 1.3 times the optimum moisture content to a minimum depth of 18 inches below slab subgrade ame Mr. Michael Roletti RESG, Inc. Project No. 0-252-104400 August 24, 2000 Page (16) Presoaking or moisture conditioning may be achieved in a number of ways. Based on our professional experience, we have found that minimizing the moisture loss on pads that have been completed (by periodic wetting to keep the upper portion of the pad from drying out) and/or berming the lot and flooding for a short period of time (days to a few weeks) are some of the more efficient ways to meet the presoaking recommendations. If flooding is performed, a couple of days to let the upper portion of the pad dry out and form a cmst so equipment can be utilized should be anticipated. 6.3 SETTLEMENT The recommended allowable bearing capacity is generally based on a total static settlement of 3/4 inche. Differential settlement is likely to be approximately one-half of the total settlement shortly after application of the building load. 6.4 LATERAL EARTH PRESSURES AND RETAINING WALL DESIGN CONSIDERATIONS The recommended lateral pressures forthe site soil (expansion index less than 90 per UBC Table 18-I-B) or either granular on site soils or import soils (expansion index less than 30) for level backfill conditions are presented in Table 5. TABLE 5 Lateral Earth Pressures Conditions Equivalent Fluid Weight (pcf) Conditions Expansive Onsite Soils (El <90) Import Soils or Granular Onsite Soils (EIOO) Active 45 35 At-Rest 70 55 Passive 325 325 Embedded stmctural walls should be designed for lateral earth pressures exerted on them. The magnitude of these pressures depends on the amount of deformation that the wall can yield under load. If the wall can yield enough to mobilize the full shear strength of the soil, it can 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 stmcture moves toward the soils, the resulting resistance developed by the soil is the "passive" resistance. For design purposes, the recommended equivalent fluid pressure foreach case for walls founded above the static ground water and backfilled with import soils of very low to low expansion potential or onsite (moderately expansive soils) is provided in Table 5. The equivalent fluid pressure values assume free-draining conditions. If conditions other than those assumed above ame Mr. Michael Roletti RESG. Inc. August 24. 2000 Project No. 0-252-104400 Page (17) are anticipated, the equivalent fluid pressure values should be provided on an individual-case basis by the geotechnical engineer. Surcharge loading effects from the adjacent stmctures should be evaluated by the geotechnical engineer. All retaining wall structures should be provided with appropriate drainage and appropriately waterproofed. The outlet pipe should be sloped to drain to a suitable outlet Typical wall drainage design is illustrated in Appendix C. For sliding resistance, the friction coefficient of 0.35 may be used at the concrete and soil interface. In combining the total lateral resistance, the passive pressure or the frictional resistance should be reduced by 50 percent. Wall footings should be designed in accordance with stmctural considerations. The passive resistance value may be increased by one-third when considering loads of short duration such as wind or seismic loads. The backfill soils should be compacted to at least 90 percent relative compaction (based on ASTM Test Method D 1557). The walls should be constmcted and backfilled as soon as possible after back-cut excavation. Prolonged exposure of back-cut slopes may result in some localized slope instability. Foundations for retaining walls in competent formational soils or properiy compacted fill should be embedded at least 18 inches below lowest adjacent grade. At this depth, an allowable bearing capacity of 2,000 psf may be assumed. 6.5 PRELIMINARY PAVEMENT DESIGN For preliminary design purposes, we have utilized a design R-value of 12 for the pavement subgrade soils based on our laboratory test results. It is recommended that representative samples of actual subgrade materials be obtained after grading and tested to provide the final pavement design. The project architect should review the provided traffic index indices prior to final design. Utilizing the design procedures outlined in the cun-ent Caltrans Highway Design Manual and a design R-value of 12, we provide the following preliminary pavement sections for planning purposes. We are presenting the preliminary pavement sections based on 2 traffic indices. The project civil engineer/architect should determine the appropriate traffic index. • Traffic Index = 4.5 (20 vear design life) 3.0 inches of asphalt concrete over 7.0 inches of Caltrans Class 2 aggregate base • Traffic Index - 5.0 (20 vear design life) 3.0 inches of asphalt concrete over 8.5 inches of Caltrans Class 2 aggregate base, or 3.5 inches of asphalt concrete over 7.5 inches of Caltrans Class 2 aggregate base, or 4.0 inches of asphalt concrete over 6.5 inches of Caltrans Class 2 aggregate base ame Mr. Michael Roletti RESG, Inc. August 24, 2000 Project No. 0-252-104400 Page (18) A traffic index of 4.5 is typically used for parking areas for passenger vehicles with an average daily traffic index of less than 200 vehicles. A traffic index of 5.0 is similar to a cut-de-sac or local street with an average daily traffic of less than 1,200 passenger vehicles with minor tmck traffic. For pavement areas subject to trash tmck or other heavy loading a Portland Cement Concrete (PCC) pavement is recommended. We recommend a minimum of 6 inches of PCC on native soils. The PCC pavement should be provided with appropriate steel reinforcement and crack- control joints as designed by the project stmctural engineer. Minmum reinforcement should consist of No. 3 rebars at 18 inches (on center) at slab midheight which continues through all crack-control joints but not through expansion joints. If saw-cuts are used, they should be a minimum depth of 1/4 ofthe slab thickness and made within 24 hours of concrete placement. We recommend that sections be as neariy square as possible. A 3.250 psi concrete mix should be utilized. Asphalt Concrete (AC) and Class 2 base materials should conform to and be placed in accordance with the latest revision of the California Department of Transportation Standard Specifications (Caltrans). The pavement subgrade should be finm and unyielding when the pavement section is placed. The upper 12 inches of subgrade soils should be moisture conditioned and compacted to at least 95 percent relative compaction based on ASTM Test Method D1557 prior to placement of aggregate base. The base layer should be compacted to at least 95 percent relative compaction as determined by ASTM Test Method D1557. Untreated Class 2 aggregate base (not processed miscellaneous base) shouid meet the four criteria of Section 26-1.02A of the most recent Caltrans specifications. We recommend that the cutts, gutters, and sidewalks be designed by the civil engineer or stmctural engineer. Curbs adjacent to paved areas should have bases in the subgrade material, not the aggregate base course, to provide a cut-off to reduce water migration into the subgrade soils. We suggest control joints, at appropriate intervals, as determined by the civii or stmcture engineer, be considered. We also suggest welded-wire mesh reinforcement and a minimum thickness of 4 inches for sidewalk slabs. We recommend steps be taken to prevent the subgrade soils from becoming saturated. Paved areas should be properiy sloped so that water does not pond and infiltrate into the pavement subgrade. Concrete swales should be designed in roadway or paridng areas subject to concentrated surface mnoff. amecP Mr. Michael Roletti RESG, Inc. August 24. 2000 Project No. 0-252-104400 Page (19) 6.6 CONTROL OF SURFACE WATER AND DRAINAGE CONTROL Positive drainage of surface water away from structures is very important No water should be allowed to pond adjacent to buildings. Positive drainage may be accomplished by providing drainage away from buildings at a gradient of at least 2 percent for a distance of at least 5 feet and further maintained by a swale or drainage path at a gradient of at least 1 percent Where limited by 5-foot side yards, drainage should be directed away from foundations for a minimum of 3 feet and into a collective swale or pipe system. Where necessary, drainage paths may be shortened by use of area drains and collector pipes. Eave gutters are recommended to reduce water filtration into the subgrade soils. Landscaping should be of a drought-tolerant variety and use drip irrigation systems or other methods to reduce water infiltration in the subsurface per the landscape architect. 6.7 SOIL CORROSIVITY In general soil environments that are detrimental to concrete have high concentrations of soluble sulfates and/or pH values of less than 5.5. Table 19-A-4 of UBC, 1997 provides specific guidelines for the concrete mix-design when the soluble sulfate content of the soil exceeds 0.1 percent by weight or 1000 ppm. The minimum amount of chloride ions in the soil environment that are corrosive to steel, either in the form of reinforcement protected by concrete cover, or plain steel substmctures such as steel pipes or piles is 500 ppm per California Test 532. The results of our laboratory tests on representative soils from the site indicated a soluble sulfate content of 0.024 percent suggests that the concrete should be designed in accordance with the Negligible Category of Table 19-A-4 of UBC, 1997. The test result also indicates a chloride content of barely less than 500 ppm, and a minimum resistivity of 935 ohm-cm, which indicates that the soil is severely corrosive with respect to ferrous metals. The test results are provided in Appendix B. Based on the results of the minimum resistivity testing, it is recommended that reinforcing bars within concrete which is in contact with the soil be covered by 3 or more inches of concrete. It is also recommended that buried metal pipes not be used or should be provided with some form of corrosion protection such as epoxy coating or cathodic protection. Although the sulfate content results indicate a negligible sulfate exposure, AGRA also recommends the use of Type II modified Portland cement The above provides general guidelines for the on-site soils. For the appropriate evaluation and mitigation design for the proposed stmctures and other substances with potential influence from corrosive soils, a corrosion engineer may be consulted. These other substances include, but are not necessarily limited to, buried copper tubing, aluminum elements in close vicinity of soils, or stucco finish that can be potentially influenced. ame(P Mr. Michael Roletti RESG, Inc. August 24. 2000 Project No. 0-252-104400 Page (20) 6.8 FLATWORK RECOMMENDATIONS Since the site is underiain by expansive soils, differential heave ofthe site flatwork will likely occur over the life of the project This heave can be reduced by using a 4-inch (minimum) thickness for all flahvoric and one of the following methods: • Flatwork should be underiain by a minimum of 4 inches of Class 2 Base or pea gravel. Flatwork should be reinforced with 6x6-6/6 welded wire mesh at slab midheight, or • Flatwork should be underiain by native soils. Flatwork should be reinforced with No. 3 rebars at 18 inches on center (each way), at slab midheight For both cases, slabs should have crack control joints at appropriate spacings and near all comers. Slab subgrade should be presoaked in accordance with the recommendations in Section 6.2.3. 7.0 CONSTRUCTION OBSERVATION, LIMITATIONS, AND PLAN REVIEW The conclusions and recommendations in this report are based in part upon data that were obtained from a limited number of observations, site visits, excavations, samples, and tests which were deemed representative ofthe site conditions at the time ofthe subsurface investigation. The nature of many sites is such that differing geotechnical or geological conditions can occur within small distances and under varying climatic conditions. Changes in subsurface conditions can and do occur overtime. Therefore, the findings, conclusions, and recommendations presented in this report can be relied upon only if AGRA has the opportunity to observe the subsurface conditions during grading and constmction of the project, in order to confirm that our preliminary findings are representative for the site. In addition, we recommend that this office have an opportunity to review the final grading and foundation plans in order to provide additional site-specific recommendations. ame Mr. Michael Roletti RESG. Inc. August 24. 2000 Project No. 0-252-104400 Page (21) 8.0 REFERENCES CDMG. 1996. Probabilistic Seismic Hazard Assessment for the State of Califomia. Open-File Report No. 96-08. Hart, 1994, Fault-Rupture Hazard Zones in Califomia, Alquist-Priolo Special study Zones Act of 1972 with Index to Special Study Zones Maps: Department of Conservation, Division of Mines and Geology, Special Publication 42. Housner, G.W. 1970, Strong Ground Motion, jn Earthquake Engineering, Robert Wiegel (ed.), pp. 75-92. International Conference of Building Officials. 1997, Uniform Building Code. Ishihara, K.. 1985, "Stability of Natural Deposits during Earthquakes", Proceedings ofthe Eleventh International Conference of Soil Mechanics and Foundation Engineering, A.A. Belkema Publishers, Rotterdam, Netheriands. Ken Stocton Architect. 2000. 24-Unit Housing Development 670 Laguna Drive. Carisbad. CA, dated, Febmary 5, 2000, Sheets No. Al and A2 Marcuson. W.F., HI. and W.A. Bieganousky. 1977, "SPT and Relative Density in Coarse Sands", Journal ofthe Geotechnical Engineering Division, ASCE 103 (FT11): 1295-1309. National Research Council, 1985, "Liquefaction of Soils During Earthquakes" Report No.: CETS- EE-001, National Academy Press. Washington, D.C. Schnabel, P.B., and Seed, H.B., 1973, Accelerations in Rock for Earthquake in the Westem United States, Seismological Society of America Bulletin. Vol. 63, No. 2, pp. 501-575. Seed, H.B., and Idriss, I.M., 1971, "Simplified Procedure for Evaluating Soil Liquefaction Potential", Journal ofthe Soil mechanics and Foundation Division, ASCE 97 (SM9): 1249- 1273. , 1982. "Ground Motions and Soil Liquefaction During Earthquake", Monograph Series, Earthquake Engineering Research Institute, Bericeley, Califomia. Seed, H.B., Idriss, I.M., and Kiefer, F.W., 1969, Characteristics of Rock Motions During Earthquakes, JSMFD, ASCE, WE95, No. SMS, pp. 1199-1218. amecP Mr. Michael Roletti RESG. Inc. August 24. 2000 Project No. 0-252-104400 Page (22) Seed, H.B., Murarida, R., Lysmer, J., and Idriss, I., 1975, "Relationships Behveen Maximum Acceleration, Maximum Velocity, Distance from Source and Local Site Conditions for Moderately Strong Earthquake", Report No. EERC 75-17, University of California, Berkeley. , 1976, Relationships of Maximum Accelerations, Maximum Velocity, Distance from Source and Local Site Conditions for Moderately Strong Earthquakes, Bull, Seism, Soc. Amer., 66:4, dated August Tan, S. S., and Kennedy, M. P., 1996, Geologic Maps of the Northwestem Part of San Diego County. Califomia. Plate I. Geologic Map of Oceanside, San Luis Rey, and San Marcos 7.5' Quadrangles, San Diego County Califomia, map scale 1:24,000. Mualchin. L.. 1996. Califomia Seismic Hazard Map: State of Califomia Department of Transportation, map scale 1:1,500,000. Unifomi Building Code, 1997, International Conference of Building Officials, Vol. 2, with Maps of Known Active Fault Near-Source Zones in Califomia and Adjacent Portions of Nevada, map scale 1:156.000. United States Department of Agriculture. Aerial Photograph, Flight No. AXN-14, Frame No. 19, dated 5/2/53. APPENDIX A RESG. Inc. Job. No. 0-252-104400 09/03/2000 Page A-1 UNIFIED SOIL CLASSIFICATION Ft Highly Organic ^ils Silts and Clays Liquid Limit >50% Silts and Clays Liquid Limit <50% Fine Grained Soils (more than 50% is smaller than No. 200 sieve) SC SM Sands with Fines Clean Sands >12% Fines I <5% Fines SP SW Sands - more than 50% of coarse fraction is smaller than No. 4 sieve 3ravels with Fines >12% Fines Clean Gravels <5% Fines . Gravels - more than 50% of coarse fraction is larger than No, 4 sieve Coarse Grained Soils (more than 50% is larqer than No. 200 sieve) 2 a O / •yl y M (or nor LOI OL LOI OL LABORATORY CLASSIFICATION CRITERIA GW and SW: Cu = •„ /D^ greater than 4 for GW, greater than 6 for SW Cc = Djo'/Deo X D,o between 1 and 3 GP and SP: Clean gravel or sand not meeting requirements for GW and SW GM and SM: Atterberg Limits below "A" LINE and PI less than 4 GC and SC: Atterberg Limits above "A" LINE and PI greater than 7 Silt or Clay Fine Sand Medium Sand Coarse Sand Fine Gravel Coarse Gravel Cobble Boulder Sieve2( Size >o 40 10 4 3/4" 3 1 2" 20 40 60 80 LIQUID LIMIT Classification of earth materials is based on field inspection and should not be construed to imply laboratory analysis unless so stated MATERIAL SYMBOLS Asphalt Calcaerous Sandstone Concrete Conglomerate Sandstone Silty Sandstone Clayey Sandstone Siltstone Sandy Siltstone Clayey Siltstone /Silty Claystone Claystone/Shale Marl Limestone 7~y-. / / Dolostone zzz: A A i .1 Breccia Volcanic Ash/Tuff •7—V V V V + + • • + + + + CONSISTENCY CLASSIFICATION FOR SOILS According to the Standard Penetration Test Blows / Foot* Granular Blows / Foot* Cohesive 0-5 Very Loose 0-2 Very Soft 6-10 Loose 2-4 Soft 11-30 \1edium Dense 4-8 Medium Stiff 31-50 Dense 8-15 Stiff 50 Very Dense 15-30 Very Stiff >30 Hard ' using 140-lb. hammer with 30" drop = 350 ft-lb/blow LEGEND OF BORING Metamorphic Rock Unit Chanae Metamorphic Rock Bulk Sample 1 -q Quartzite Extrusive Igneous Rod Driven Sample Water Level ^ Unconformity. . Material_Chang6 _ Intrusive Igneous RocK -Bottom of the Borina "NSR" indicates NO SAMPLE RECOVERY RESG, Inc. Job. No. 0-252-104400 09/03/2000 Page A-2 TEST BORING LOG BORING: B-1 Sheet 1 of 1 Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21 Hole Diameter (in): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor: C & K Drilling Depth to Groundwater (ft): 16 Boring Completion: Backfilled w/cuttings on 8/8/0(f Caving: None observed 116 14.5 17 36 122 12.3 1.4" Bulk 2.5" 45 -62 1.4" 2.5" V/. 2 10 15 20 1 i. SM CL FILL Brown, damp, loose SILTY SAND. COLLUVIUM: Brown, moist, very stiff SANDY CLAY interiayered with medium dense CLAYEY SAND. GC TERRACE DEPOSITS: Presence of gravel and cobbles indicates terrace deposits as encountered in near-by borings. SANTIAGO FORMATION: White to light yellow-brown, moist CLAYEY SANDSTONE, weakly to moderately cemented. ...saturated. 25 NOTES: 1. Approximate surface elevation obtained from USGS 7.5' Topographic Series, Encinitas Quadrangle, map scale 1:24000. 2. Sampler driven by 140-lb hammer falling from 30" height. a> Q. (0 p lU^ 0.9- Q ® UJ '£ 2« «) I" Q Q. Q O O so 1 o o « II 0) a li" » a E n CO o z _« a E ca OT « ll IS Q Q. 0) « «) QS:, c _ o 5 « OT o xi£ « OT - OT C « 30 THIS BORING LOG SUMMARY APPLIES ONLY AT THE TIME AND LOCATION INDICATED. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND TIMES. Logged by: TMM RESG, inc. Job. No. 0-252-104400 09/03/2000 Page A-3 TEST BORING LOG BORING: B-2 Sheet 1 of 1 Date(s) Drilled: 8/8/00 Surface Elevation (ft): ~40 Total Depth of Boring (ft): 21 Hole Diameter (in): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor: C & K Drilling Depth to Groundwater (ft): 15 Boring Completion: Backfilled w/cuttings on8/8j0^aving: None observed 117 21 11.1 113 16.9 Bulk 1.4" 40 70 -84 2.5" I 1= 10 1.4" 2.5" 20 _]: SM CL SC FILL Brown, damp, loose SILTY SAND. COLLUVIUM: Brown, moist, medium stiff SANDY CLAY. TERRACE DEPOSITS: Greenish brown, moist, medium dense CLAYEY SAND; white and orange streaks; scattered gravel. ...increased gravel. SANTIAGO FORMATION: White to light yellow-brown, wet CLAYEY SANDSTONE, weakly to moderately cemented. .saturated. 25 NOTES: 1. Approximate surface elevation obtained from USGS 7.5' Topographic Series, Encinitas Quadrangle, map scale 1:24000. 2. Sampler driven by 140-lb hammer falling from 30" height. •^. "> ^ o 0) a a. OT u 0.9- LU B OT Q a O O So O w II ma 0) a >> £ a. E n OT a E m OT n fl IS a £ O. o c ll •OS .£ « C M "E « 30 THIS BORING LOG SUMMARY APPLIES ONLY AT THE TIME AND LOCATION INDICATED. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND TIMES. Logged by: TMM RESG. Inc. Job. No. 0-252-104400 09/03/2000 Page A-4 TEST BORING LOG BORING: B-3 Sheet 1 of 1 Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21.5 Hole Diameter (in): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor: C & K Drilling Depth to Groundwater (ft): 18 Boring Completion: Backfilled w/cuttings on Caving: None observed "BuII< 107 17.9 120 14.2 10 30 -62 62 2.5" 1.4" 2.5" 1.4" 10 20 j: 25 1 15 2 SM CL SC FILL: Brown, damp, loose SILTY SAND. COLLUVIUM: Brown, moist, medium stiff SANDY CLAY. TERRACE DEPOSITS: Greenish brown, moist, medium dense SILTY SAND; scattered gravel. SANTIAGO FORMATION: White to light yellow-brown, moist CLAYEY SANDSTONE, weakly to moderately cemented. ...saturated. NOTES: 1. Approximate surface elevation obtained from USGS 7.5' Topographic Series, Encinitas Quadrangle, map scale 1:24000. 2. Sampler driven by 140-lb hammer falling from 30" height. B a> c O a. OT o uJtS 0.9-z 5 Q « UJ b I" Q If 5 o So I? O 18 ll me « a >< I- 0 a E i« OT O z 9) a. E m OT (0 ll i=S Q. V fl> 4) c _ o OT u 2 « E « DO THIS BORING LOG SUMMARY APPLIES ONLY AT THE TIME AND LOCATION INDICATED. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND TIMES. Logged by: TMM RESG, Inc. Job. No. 0-252-104400 09/03/2000 Page A-5 TEST BORING LOG BORING: B-4 Sheet 1 of 1 Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21.5 Hole Diameter (In): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor: C & K Drilling Depth to Groundwater (ft): 18 Boring Completion: Backfilled w/cuttings on Caving: None observed "BOUT 106 17.1 122 13.2 36 42 68 2.5" 1.4" 2.5" 1.4" 10 15 20 I. SM CL GC FILL: Brown, damp, loose SILTY SAND. COLLUVIUM: Brown, moist, medium stiff SANDY CLAY. TERRACE DEPOSITS: Presence of gravel and cobbles, up to 6" diameter, indicates terrace deposits as encountered in near-by borings. SANTIAGO FORMATION: White to light yellow-brown, moist CLAYEY SANDSTONE, weakly to moderately cemented. ...saturated. 25 NOTES: 1. Approximate surface elevation obtained from USGS 7.5' Topographic Series, Encinitas Quadrangle, map scale 1:24000. 2. Sampler driven by 140-lb hammer falling from 30" height. S c O 0. OT O 0.9-z 5 UJ B m I's Q a o ic i8 O w II « a >> I- ffl a E OT « a E n OT S .EE o Q. O a it c _ o O'S OT o T5£ « M I? M Ci2 30 THIS BORING LOG SUMMARY APPLIES ONLY AT THE TIME AND LOCATION INDICATED. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND TIMES. Logged by: TMM RESG, Inc. Job. No. 0-252-104400 09/03/2000 Page A-6 TEST BORING LOG BORING: B-5 Sheet 1 of Date(s) Drilled: 8/8/00 Surface Elevation (ft): -40 Total Depth of Boring (ft): 21 Hole Diameter (In): 8 3/4 Rig Type: Hollow Stem Auger Drilling Contractor: C & K Drilling Depth to Groundwater (ft): 18.5 Boring Completion: Backfilled w/cuttings on 8/8/0(7 Caving: None observed 123 12 12 -68 1.4" 2.5" 48 121 14 -98 1.4" Bulk 2.5" 10 I I 2 15 I 20 COLLUVIUM: Brown, moist, stiff SANDY CLAY; minute voids. GC "SC TERRACE DEPOSITS: , Greenish brown, moist, medium dense CLAYEY \ J^?^^Y^^ scattered cobbles. j GreenisFbrown, rnoist, mediurn dense (IL/WEY SAND; scattered gravel and cobbles. SANTIAGO FORMATION: White to light yellow-brown, moist CLAYEY SANDSTONE, weakly to moderately cemented. .saturated. 25 NOTES: 1. Approximate surface elevation obtained from USGS 7.5' Topographic Series, Encinitas Quadrangle, map scale 1:24000. 2. Sampler driven by 140-lb hammer falling from 30" height. P c o a. OT o UJ^ O.S-z 5 Ui B OT Q Q. a o o So 1 o iiS O OT ll o a. >. « a E (0 OT 0) Q. E n OT ll Q. O c ll •oE ,2 « C OT E « 30 THIS BORING LOG SUMMARY APPLIES ONLY AT THE TIME AND LOCATION INDICATED. SUBSURFACE CONDITIONS MAY DIFFER AT OTHER LOCATIONS AND TIMES. Logged by: TMM APPENDIX B Mr. Tim Carroll O'Day Consultants Project No. 0-252-103800 July 21.2000 Page (B-1) APPENDIX B Laboratory Testing Procedures and Test Results Expansion Index Tests: The expansion potential of selected materials was evaluated by the Expansion Index Test U.B.C. Standard No. 18-2. Specimens are molded under a given compactive energy to approximately the optimum moisture content and approximately 50 percent saturation or approximately 90 percent relative compaction. The prepared 1-inch thick by 4-inch diameter specimens are loaded to an equivalent 144 psf surcharge and are inundated with tap water until volumetric equilibrium is reached. The results of these tests are presented in the table below: Sample Location Sample Description Compacted Dry Density (pen Expansion Index Expansion Potential B-1 @ 6" Brown clayey sand 94.0 108 High B-3 @ 0'-4' Brown silty sand 115.6 0 Very Low Consolidation/Collapse Testing: Selected samples were loaded in a consolidometer to the proposed overburden pressure. The samples were then inundated with water and the percent hydrocollapse was measured and recorded below. A negative value indicates swell. Sample Location % Hydrocollapse B-3. 5' -0.83 @ 1000 psf (expansion) Classification or Grain Size Tests: Typical materials were subjected to mechanical grain-size analysis by sieving from U.S. Standard brass screens (ASTM Test Method D422). Hydrometer analyses were performed where appreciable quantities of fines were encountered. The data was evaluated in determining the classification of the materials. The grain-size distribution curves are presented in the test data and the Unified Soil Classification (USCS) is presented in both the test data and the logs. Below is a summary of the percent passing the No. 200 Sieve. Mr. Tim Carroll O'Day Consultants Project No. 0-252-103800 July 21. 2000 Page (B-2) Sample Location Percent Passing No. 200 Sieve B-1. 5*-7' 64 B-2. 2'-5' 50 Chloride Testing: Representative soil samples were obtained for testing for chloride content in accordance with Califomia Test Method 422. The results are presented in the following table. Sample Location Chloride Content, ppm Chloride Attack Potential* B-2. 2'-5' 490 Moderate 1 *Per Cal Test Method 532 and City of San Diego Program Design Guidelines for Consultants, 1992. | Minimum Resistivity and pH Tests: Minimum resistivity and pH tests were performed in general accordance with California Test Method 643. The results are presented in the table below: Sample Location Minimum Resistivity (ohms-cm) Corrosion Potential* B-2. 2'-5' 8.0 937 Very High * per City of San Diego Program Design Guidelines for Consultants, 1992. "R"-Value: The resistance "R"-value was determined by the California Materials Method No. 301 for base, subbase, and basement soils. The samples were prepared and exudation pressure and "R"-value determined. The graphically determined "R"-value at exudation pressure of 300 psi is reported. Sample Number R-Value B-1,5'-7' 12 Mr. Tim Carroll O'Day Consultants Project No. 0-252-103800 July 21, 2000 Page (B-3) Moisture and Density Determination Tests: Moisture content and dry density determinations were performed on relatively undisturbed samples obtained from the test borings. The results of these tests are presented in the boring logs. Where applicable, only moisture content was determined from "undisturbed" or disturbed samples. Soluble Sulfates: The soluble sulfate contents of selected samples were determined by standard geochemical methods. The test results are presented in the table below: Sample Location Soluble Sulfate Content {%) 1 Sulfate Exposure* B-2, 2'-5' 0.024 Negligible * Based on the 1997 edition of the Uniform Building Code, Table No. 19-A-4, prepared by the International Conference of Building Officials (ICBO, 1997). Direct Shear Tests: Direct shear tests were performed 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 testing apparatus at a strain rate of 0.0025 inches per minute. The test results are presented in the test data. Sample Location Sample Description Friction Angle (degrees) Apparent Cohesion (psf) B-3, 5'-6' Sandy Clay 25 300 APPENDIX C GENERAL EARTHWORK AND GRADING SPECIFICATIONS FOR ROUGH GRADING 1.0 General 1.1 Intent: These General Earthwork and Grading Specifications are for the grading and earthwork shown on the approved grading plan(s) and/or indicated in the geotechnical report(s). These Specifications are a part of the recommendations contained in the geotechnical report(s). In case of confiict, the specific recommendations in the geotechnical report shall supersede these more general Specifications. Observations of the earthwork by the project Geotechnical Consultant during the course of grading may result in new or revised recommendations that could supersede these specifications or the recommendations in the geotechnical report(s). 1.2 The Geotechnical Consultant of Record: Prior to commencement of work, the owner shall employ the Geotechnical Consultant of Record (Geotechnical Consultant). The Geotechnical Consultants shall be responsible for reviewing the approved geotechnical report(s) and accepting the adequacy of the preliminary geotechnical findings, conclusions, and recommendations prior to the commencement of the grading. Prior to commencement of grading, the Geotechnical Consultant shall review the "work plan" prepared by the Earthwork Contractor (Contractor) and schedule sufficient personnel to perform the appropriate level of observation, mapping, and compaction testing. During the grading and earthwork operations, the Geotechnical Consultant shall observe, map, and document the subsurface exposures to verify the geotechnical design assumptions. If the observed conditions are found to be significantly different than the interpreted assumptions during the design phase, the Geotechnical Consultant shall inform the owner, recommend appropriate changes in design to accommodate the observed conditions, and notify the review agency where required. Subsurface areas to be geotechnically observed, mapped, elevations recorded, and/or tested include natural ground after it has been cleared for receiving fill but before fill is placed, bottoms of all "remedial removal" areas, all key bottoms, and benches made on sloping ground to receive fill. The Geotechnical Consultant shall observe the moisture-conditioning and processing of the subgrade and fill materials and perfonn relative compaction testing of fill to determine the attained level of compaction. The Geotechnical Consultant shall provide the test results to the owner and the Contractor on a routine and frequent basis. 1.3 The Earthwork Contractor: The Earthwori< Contractor (Contractor) shall be qualified, experienced, and knowledgeable in earthwori< logistics, preparation and processing of ground to receive fill, moisture-conditioning and processing of fill, and compacting fill. The Contractor shall review and accept the plans, geotechnical report(s), and these Specifications prior to commencement of grading. The Contractor shall be solely responsible for performing the grading in accordance with the plans and specifications. The Contractor shall prepare and submit to the owner and the Geotechnical Consultant a wori< plan that indicates the sequence of earthwork grading, the number of "spreads" of wori< and the estimated quantities of daily earthwork contemplated forthe site priorto commencement of grading. The Contractor shall inform the owner and the Geotechnical Consultant of changes in work schedules and updates to the work plan at least 24 hours in advance of such changes so that appropriate observations and tests can be planned and accomplished. The Contractor shall not assume that the Geotechnical Consultant is aware of all grading operations. The Contractor shall have the sole responsibility to provide adequate equipment and methods to accomplish the earthwork in accordance with the applicable grading codes and agency ordinances, these Specifications, and the recommendations in the approved geotechnical report(s) and grading plan(s). If, in the opinion of the Geotechnical Consultant, unsatisfactory conditions, such as unsuitable soil, improper moisture condition, inadequate compaction, insufficient buttress key size, adverse weather, etc., are resulting in a quality of work less than required in these specifications, the Geotechnical Consultant shall reject the work and may recommend to the owner that construction be stopped until the conditions are rectified. 2.0 Preparation of Areas to be Filled 2.1 Clearing and Grubbing: Vegetation, such as bmsh, grass, roots, and other deleterious material shall be sufficiently removed and properly disposed of in a method acceptable to the owner, goveming agencies, and the Geotechnical Consultant The Geotechnical Consultant shall evaluate the extent of these removals depending on specific site conditions. Earth fill material shall not contain more than 1 percent of organic materials (by volume). No fill lift shall contain more than 5 percent of organic matter. Nesting ofthe organic materials shall not be allowed. If potentially hazardous matierials are encountered, the Contractor shall stop work in the affected area, and a hazardous material specialist shall be infonmed immediately for proper evaluation and handling of these materials priorto continuing to work in that area. As presently defined by the State of California, most refined petroleum products (gasoline, diesel fuel, motor oil, grease, coolant, etc.) have chemical constituents that are considered to be hazardous waste. As such, the indiscriminate dumping or spillage of these fluids onto the ground may constitute a misdemeanor, punishable by fines and/or imprisonment, and shall not be allowed. 2.2 Processing: Existing ground that has been declared satisfactory for support of fill by the Geotechnical Consultant shall be scarified to a minimum depth of 6 inches. Existing ground that is not satisfactory shall be overexcavated as specified in the following section. Scarification shall continue until soils are broken down and free of large clay lumps or clods and the working surface is reasonably unifomi, flat, and free of uneven features that would inhibit uniform compaction. 2.3 Overexcavation: In addition to removals and overexcavations recommended in the approved geotechnical report(s) and the grading plan, soft, loose, dry, saturated, spongy, organic-rich, highly fractured or otherwise unsuitable ground shall be overexcavated to competent ground as evaluated by the Geotechnical Consultant during grading. 2.4 Benching: Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal to vertical units), the ground shall be stepped or benched. Please see the Standard Details for a graphic illustration. The lowest bench or key shall be a minimum of 15 feet wide and at least 2 feet deep, into competent material as evaluated by the Geotechnical Consultant. Other benches shall be excavated a minimum height of 4 feet into competent material or as otherwise recommended by the Geotechnical Consultant Fiil placed on ground sloping flatterthan 5:1 shall also be benched or otherwise overexcavated to provide a flat subgrade for the fill. 2.5 Evaluation/Acceptance of Fill Areas: All areas to receive fill, including removal and processed areas, key bottoms, and benches, shall be observed, mapped, elevations recorded, and/or tested prior to being accepted by the Geotechnical Consultant as suitable to receive fill. The Contractor shall obtain a written acceptance from the Geotechnical Consultant prior to fill placement A licensed surveyor shall provide the survey control for determining elevations of processed areas, keys, and benches. 3.0 Fill Material 3.1 General: Material to be used as fill shall be essentially free of organic matter and other deleterious substances evaluated and accepted by the Geotechnical Consultant prior to placement Soils of poor quality, such as those with unacceptable gradation, high expansion potential, or low strength shall be placed in areas acceptable to the Geotechnical Consultant or mixed with other soils to achieve satisfactory fill material. 3.2 Oversize: Oversize material defined as rock, or other irreducible material with a maximum dimension greater than 8 inches, shall not be buried or placed in fill unless location, materials, and placement methods are specifically accepted by the Geotechnical Consultant. Placement operations shall be such that nesting of oversized material does not occur and such that oversize material is completely surrounded by compacted or densified fill. Oversize material shall not be placed within 10 vertical feet of finish grade or within 2 feet of future utilities or underground construction. 3.3 Import: If importing of fill material is required for grading, proposed import material shall meet the requirements of Section 3.1. The potential import source shall be given to the Geotechnical Consultant at least 48 hours (2 working days) before importing begins so that its suitability can be determined and appropriate tests performed. 4.0 Fill Placement and Compaction 4.1 Fill Layers: Approved fill material shall be placed in areas prepared to receive fill (per Section 3.0) in near-horizontal layers not exceeding 8 inches in loose thickness. The Geotechnical Consultant may accept thicker layers if testing indicates the grading procedures can adequately compact the thicker layers. Each layer shall be spread evenly and mixed thoroughly to attain relative uniformity of material and moisture throughout 4.2 Fill Moisture Conditioning: Fill soils shall be watered, dried back, blended, and/or mixed, as necessary to attain a relatively uniform moisture content at or slightly over optimum. Maximum density and optimum soil moisture content tests shall be performed in accordance with the American Society of Testing and Materials (ASTM Test Method D1557-91). 4.3 Compaction of Fill: After each layer has been moisture-conditioned, mixed, and evenly spread, it shall be uniformly compacted to not less than 90 percent of maximum dry density (ASTM Test Method Dl 557-91). Compaction equipment shall be adequately sized and be either specifically designed for soil compaction or of proven reliability to efficiently achieve the specified level of compaction with uniformity. 4.4 Compaction of Fill Slopes: In addition to nonnal compaction procedures specified above, compaction of slopes shall be accomplished by backrolling of slopes with sheepsfoot rollers at increments of 3 to 4 feet in fill elevation, or by other methods producing satisfactory results acceptable to the Geotechnical Consultant Upon completion of grading, relative compaction of the fill, out to the slope face, shall be at least 90 percent of maximum density per ASTM Test Method Dl 557-91. 4.5 Compaction Testing: Field tests for moisture content and relative compaction ofthe fill soils shall be performed by the Geotechnical Consultant Location and frequency of tests shall be at the Consultant's discretion based on field conditions encountered. Compaction test locations will not necessarily be selected on a random basis. Test locations shall be selected to verify adequacy of compaction levels in areas that are judged to be prone to inadequate compaction (such as close to slope faces and at the fill/bedrock benches). 4.6 Freguencv of Compaction Testing: Tests shall be taken at intervals not exceeding 2 feet in vertical rise and/or 1,000 cubic yards of compacted fill soils embankment In addition, as a guideline, at least one test shall be taken on slope faces for each 5.000 square feet of slope face and/or each 10 feet of vertical height of slope. The Contractor shall assure that fill constmction is such that the testing schedule can be accomplished by the Geotechnical Consultant The Contractor shall stop or slow down the earthwork construction if these minimum standards are not met 4.7 Compaction Test Locations: The Geotechnical Consultant shall document the approximate elevation and horizontal coordinates of each test location. The Contractor shall coordinate with the project surveyor to assure that sufficient grade stakes are established so that the Geotechnical Consultant can determine the test locations with sufficient accuracy. At a minimum, two grade stakes within a horizontal distance of 100 feet and vertically less than 5 feet apart from potential test locations shall be provided. 5.0 Subdrain Installation Subdrain systems shall be installed in accordance with the approved geotechnical report(s), the grading plan, and the Standard Details. The Geotechnical Consultant may recommend additional subdrains and/or changes in subdrain extent, location, grade, or material depending on conditions encountered during grading. All subdrains shall be surveyed by a land surveyor/civil engineer for line and grade after installation and prior to burial. Sufficient time should be allowed by the Contractor for these surveys. 6.0 Excavation Excavations, as well as over-excavation for remedial purposes, shall be evaluated by the Geotechnical Consultant during grading. Remedial removal depths shown on geotechnical plans are estimates only. The actual extent of removal shall be determined by the Geotechnical Consultant based on the field evaluation of exposed conditions during grading. Where fill-over-cut slopes are to be graded, the cut portion of the slope shall be made, evaluated, and accepted by the Geotechnical Consultant prior to placement of materials for construction ofthe fill portion ofthe slope, unless othen/vise recommended by the Geotechnical Consultant 7.0 Trench Backfills 7.1 The Contractor shall follow all OHSA and Cal/OSHA requirements for safety of trench excavations. 7.2 All bedding and backfill of utility trenches shall be done in accordance with the applicable provisions of Standard Specifications of Public Works Constmction. Bedding material shall have a Sand Equivalent greater than 30 (SE>30). The bedding shall be placed to 1 foot over the top ofthe conduit and densified by jetting. Backfill shall be placed and densified to a minimum of 90 percent of maximum from 1 foot above the top of the conduit to the surface. 7.3 The jetting of the bedding around the conduits shall be observed by the Geotechnical Consultant 7.4 The Geotechnical Consultant shall test the trench backfill for relative compaction. At least one test should be made for every 300 feet of trench and 2 feet of fill. 7.5 Lift thickness of trench backfill shall not exceed those allowed in the Standard Specifications of Public Works Constmction unless the Contractor can demonstrate to the Geotechnical Consultant that the fill lift can be compacted to the minimum relative compaction by his altemative equipment and method. PnOJECTEO PLANE 1 TO 1 MAXS4UM FTOU TO€ OF SLOPE TO APPROVED GftOUND NATURAL GROUND FILL SLOPE REMOVE UNSUrtABLE MATERIAL BENCH HEIGHT 2' MIN. KEY DEPTH L—15' MIN. LOWEST BENCH (KEY) NATURAL GROUND -^V-i «=—1 4'TYPK:AL ^^MPACTED—ru^r: FILL-OVER-CUT SLOPE BENCH HEIGHT -—15* MW.—<-j LOVreST BENCH' REMOVE UNSUrrABLE MATERIAL — 2'MIN. KEY DEPTH CUT FACE SHAa BE CONSmXTH) PRK3R TO HLL PLACEMefl-TO ASSURE ADEQUATE GEOLOOIC CONOmONS CUT FACC TO BE CONSmUCTED PRK>R TO FIX PLACaeiTv OVERBUILT AND TRIM BACK PnOJECTEO PLANE 1 TO 1 MAXIMUM FROM TOE OF SLOPE TO APPROVED GROUND CUT-OVER-FILL •W- SLOPE DESIGN SLOPE REMOVE NSUrrABLE MATERIAL For Subdrains See Standard Detail C 2* MIN. ' KEY DEPTH -BENCH HEIGHT ^S%KflN.-* — .»_15' MIN^^ LOWEST BENCH! (KEY) I5CH1 BQOflNQ SHAa BE DONE WHEN SLOPES ANGLE IS EQUAL TO CR GREATER THAN 5:1 MWMUM BQ«H HEIGHT SHAa BE 4 FEET MINIMUM FU. WIDTH SHAa BE 9 FEET KEYING AND BENCHING GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAILS A ^ AGRA FINISH GRADE SLOPE FACE :10' MIN.zrznr-.COMPACTED RLLrzr^ ^^^^^^^ .OVERSIZE innriWINDROW • Overstre rock Is larger than 8 inches In largest dimensfoa • Excavate a trench in the compacted fill deep erxjugh to bury all the rock. • Backfill with granular soil jetted or fkxxled In place to fill all the vokJs. • Do not bury rock within 10 feet of finish grade. • Windrow of buried rock shafl be paraflel to the fkilshed skjpe fiH JETTED OR FLOODED GRANULAR MATERIAL ELEVATION A-A' PROFILE ALONG WINDROW A JETTED OR FLOODED GRANULAR MATERIAL OVERSIZE ROCK DISPOSAL GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAILS B ^ AGRA NATURAL GROUND BENCHING REMOVE UNSUITABLE MATERIAL 2" MIN. OVERLAP FROM THE TOP HOG RING TIED EVERY 6 FEET CALTRANS CLASS II PERMEABLE OR #2 ROCK (9FT.'/FT.) WRAPPED IN FILTER FABRIC CANYON SUBDRAIN OUTLET DETAIL DESIGN FINISHED GRADE PERFORATED PIPE 6-^ MIN. FILTER FABRIC (MIRAF1140 OR^ APPROVED \COLLECTOR PIPE SHALL EQUIVALENT) BE MINIMUM 6* DIAMETER SCHEDULE 40 PVC PERFORATED PIPE. SEE STANDARD DETAIL D FOR PIPE SPECIFICATION 20' MIN .NON-PERFORAtED 6*<^ MIN. FILTER FABRIC (MIRAF1140 OR APPROVED EQUIVALENT) #2 ROCK WRAPPED IN FILTER TABRIC OR CALTRANS CLASS II PERMEABLE. CANYON SUBDRAINS GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAILS C ^ AGRA OUTLET PIPES 4'<|> NON-PERFORATED PIPE, 100' MAX. O.C. HORIZONTALLY, 30' MAX. O.C. VERTICALLY BACKCUT 1:1 OR FLATTER 2' MIN POSITIVE SEAL SHOULD BE PROVIDED AT THE JOI OUTLET PIPE (NON-PERFORATED) CALTRANS CLASS II PERMEABLE OR #2 ROCK (3Fr.'/FT.) WRAPPED IN FILTER FABRIC 12* MIN. OVERLAP FROM THE TOP HOG RING TIED EVERY 6 FEET \ FILTER FABRIC (MIRAFI140 0R APPROVED EQUIVALENT) / T-CONNECnON FOR COLLECTOR PIPE TO OUTLET PIPE • SUBDRAIN INSTALLATION - Subdrain collector pipe shafl be Instafled with perforations down or, unless otherwise designated by the geotechnical consultant Outiet pipes shall be norvperforated pipe. T?ie sutxjrain pipe shafl have at least 8 perforations unifonnly spaced per foot Perforation shall te y/ to W 9 dniled fides are used. Afl sutxjrain pipes shall have a gradient at least 2% towards the outiet • SUBDRAIN PIPE - Subdrain pipe shall be ASTM D2751, SDR 23.5 or ASTM D1527, Schedule 40, or ASTM D3034, SDR 23.5, Schedule 40 Polyvinyl Chtoride Plastk: (PVC) pipe. • Afl outlet pipe shall be placed In a trench no wider than twk» the subdrain pipe. Pipe shall be in soil of SE>.30 jetted or flooded in place except for the outside 5 feet whteh shafl t>e native sofl backfilL BUTTRESS OR REPLACEMENT FILL SUBDRAINS GENERAL EARTHWORK AND GRADING SPECIFICATIONS STANDARD DETAILS D ^ AGRA STABILITY FILL / BUTTRESS DETAIL OUTLET PIPES 4' 0 NONPERFORATED PIPE. 100' MAX. O.C. HORIZONTALLY, 30' MAX. O.c. VERTICALLY-BACK CUT 1:1 OR FLATTER BENCH SEE SUBDRAIN TRENCH DETAIL LOWEST SUBDRAIN SHOULD BE SITUATED AS LOW AS POSSIBLE TO ALLOW SUITABLE OUTLET KEY DEPTH KEY WIDTH AS NOTED ON GRADING PLANS is' MIN. PERFORATED PIPE NON-PERFORATED OUTLET PIPE I ^ 10* MIN. . " -1 EACH SIDE CAP T-COMNECTION DETAIL 6' MIN OVERLAP 3/4'-1-1/2' CLEAN GRAVEL (3ft.3/ft. MIN.) 4-/21 NON-PERFORATED PIPEs^ FILTER FABRIC ENVELOPE (MIRAFI 140N OR APPROVED EQUIVALENT)* SEE T-CONNECTION DETAIL 6' MIN. COVER 4- 0 PERFORATED PIPE 4* W\H. BEDDING SUBDRAIN TRENCH DETAIL *IF CALTRANS CLASS 2 PERMEABLE MATERIAL IS USED IN PLACE OF 3y4'-1-1/2' GRAVEL, FILTER FABRIC MAY BE DELETED SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size X Passing 1" 100 3/4" 90-100 3/8" • 40-100 No. 4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 Sand Equivalent>75 NOTES: For buttress dimensions, see oeotechnlcal report/plans. Actual dimensions of buttress and. subdrain may be changed by the geotechnical consultant based on field conditions. SUBDRAIN INSTALLATIONTSubdraIn pipe should be installed with perforations down as depicted. At locations recommended by the fleotechnicalvconsuitant, nonperforated pipe should be Installed SUBDRAIN TYPE-SubdraIn type shouid be Acrylon trtle Butadiene Styrene (A.B.S.), Polyvinyl Chloride (PVC) or approved equivalent. Class 125,SDR 32.5 should be used for maximum fill depths of 35 feet. Class 200,SDR 21 should be used for maximum fill depths of 100 feet. ^ AGRA RETAINING WALL DRAINAGE DEtAlL .SOIL BACKFILL, COMPACTED TO 00 PERCENT;RELATIVE COMPACTION* RETAINING WALL- WALL WATERPROOFING PER ARCHltECf'S SPECIFICATIONS o6'.MIN..o OVERLAP 0 o FILTER FABRIC ENVELOPE.. :(MIRAFri40N OR APPROVED EQUIVALENT):** ** -3/4'-1-1/2' CLEAN GRAVEL . 4'(MIN^ DIAMETER PERFORATED PVC PIPE (SCHEDULE 40 OR: EQUIVALENT) WITH PERFORATIONS ORIENTEOtDOWN AS DEPICTED MINIMUM 1* PERCENT GRADIENT TO SUITABLE OUTLET •SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL U.S. Standard Sieve Size % Passing 1" 100 3/4" 90-100 3/8" 40-100 No. 4 25-40 No. 8 18-33 No. 30 5-15 No. 50 0-7 No. 200 0-3 Sand Equivalent>75 MIN. COMPETENT BEDROCK OR MATERIAL AS EVALUATED BY THE GEOTECHNICAL CONSULTANT * BASED ON ASTM D1657 **IF CALTRANS CLASS 2 PERMEABLE MATERIAL (SEE GRADATION TO LEFT) IS USED IN PLACE OF 3/4'-L-1/2' GRAVEL, FILTER FABRIC MAY BE DELETED. CALTRANS CLASS 2 PERMEABLE MATERIAL SHOIH.D BE COMPACTED TO 90. PERCENTVRELATIVE COMPACTION* NOTE:COMPOSITE DRAINAGE PRODUCTS SUCH AS MIRADRAIN OR J-DRAIN MAY BE USED AS AN ALTERNATIVE TO GRAVEL OR CLASS Z INSTALLATION SHOULD BE PERFORlvED IN ACCORDANCE WITH MANUFACTURER'S SPECIRCATIONS. ^ AGRA