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2006-324 I CONSTRUCTION TESTING & ENGINEERING, INC SAN DIEGO,CA RIVERSIDE,CA VENTURA,CA TRACY,CA SACRAMENTO,CA N.PALM SPRINGS,CA 1441 Montiel Road 12155 Magnolia Ave. 1645 Pacific Ave. 242 W.Larch 3628 Madison Ave. 19020 N.Indian Ave. Suite 115 Suite 6C Suite 107 Suite F Suite 22 Suite 2-K Escondido,CA 92026 Riverside,CA 92503 Oxnard,CA 93033 Tracy,CA 95376 N.Highlands,CA 95660 N.Palm Springs,CA 92, (760)746-4955 (951)352-6701 (805)486-6475 (209)839-2890 (916)331-6030 (760)329-4677 (760)746-9806 FAX (951)352-6705 FAX (805)486-9016 FAX (209)839-2895 FAX (916)331-6037 FAX (760)328-4896-FAX PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED STREBE RESIDENCE 525 BIRMINGHAM DRIVE ENCINITAS, CALIFORNIA r�fvr f 4i',..G SERj PS S Prepared for: CHRISTY AND MATTHEW STREBE 525 BIRMINGHAM DRIVE ENCINITAS, CALIFORNIA 92007 Prepared by: CONSTRUCTION TESTING & ENGINEERING, INC. 1441 MONTIEL ROAD, SUITE 115 ESCONDIDO, CA 92026 CTE JOB NO. 10-7457G FEBRUARY 14, 2005 GEOTECHNICAL I ENVIRONMENTAL I CONSTRUCTION INSPECTION AND TESTING I CIVIL ENGINEERING I SURVEYING TABLE OF CONTENTS 1.0 INTRODUCTION AND SCOPE OF SERVICES...................................................................1 1.1 Introduction..................................................................................................................1 1.2 Scope of Services.........................................................................................................1 2.0 SITE DESCRIPTION ..............................................................................................................2 3.0 FIELD AND LABORATORY INVESTIGATIONS...............................................................2 3.1 Field Investigation........................................................................................................2 3.2 Laboratory Investigation..............................................................................................3 4.0 GEOLOGY ..............................................................................................................................3 4.1 General Setting.............................................................................................................3 4.2 Geologic Conditions ....................................................................................................4 4.2.1 Topsoils.........................................................................................................4 4.2.2 Quaternary Terrace Deposits.........................................................................5 4.3 Groundwater Conditions..............................................................................................5 4.4 Geologic Hazards.........................................................................................................5 4.4.1 Local and Regional Faulting.........................................................................6 4.4.2 Site Near Source Factors and Seismic Coefficients......................................6 4.4.3 Liquefaction Evaluation................................................................................7 4.4.4 Seismic Settlement Evaluation 4.4.5 Tsunamis, Seiche, and Flooding Evaluation.................................................8 4.4.6 Landsliding or Rocksliding...........................................................................8 - 4.4.7 Compressible and Expansive Soils...............................................................8 4.4.8 Corrosive Soils..............................................................................................9 5.0 CONCLUSIONS AND RECOMMENDATIONS...................................................................9 5.1 General ........................................................9 ................................................................. 5.2 Site Preparation............................................................................................................9 5.3 Site Excavation ..........................................................................................................10 5.4 Fill Placement and Compaction.................................................................................10 5.5 Fill Materials..............................................................................................................11 5.6 Temporary Construction Slopes.................................................................................11 5.7 Foundations and Slab Recommendations..................................................................12 5.7.1 Foundations.................................................................................................12 5.7.2 Foundation Settlement................................................................................13 5.7.3 Foundation Setback.....................................................................................13 5.7.4 Interior Concrete Slabs................................................................................14 5.8 Lateral Resistance and Earth Pressures......................................................................14 5.9 Exterior Flatwork.......................................................................................................15 5.10 Drainage...................................................................................................................16 5.11 Slopes.......................................................................................................................16 5.12 Construction Observation ........................................................................................17 5.13 Plan Review.............................................................................................................17 6.0 LIMITATIONS OF INVESTIGATION.................................................................................18 FIGURES FIGURE 1 SITE INDEX MAP FIGURE 2 EXPLORATION LOCATION MAP APPENDICES APPENDIX A REFERENCES CITED APPENDIX B EXPLORATION LOGS APPENDIX C LABORATORY METHODS AND RESULTS APPENDIX D STANDARD GRADING SPECIFICATIONS Preliminary Geotechnical Investigation Page 1 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No. 10-7457G 1.0 INTRODUCTION AND SCOPE OF SERVICES 1.l Introduction This report presents the results of Construction Testing and Engineering,Inc.'s("CTE")preliminary geotechnical investigation and provides conclusions and engineering criteria for the proposed development. It is our understanding that the property is to be developed by constructing a three- story residential structure consisting of a two-story residence over a basement.Additional proposed construction includes re-grading of the western portion of the property to allow direct access to the basement from Birmingham Drive, and other associated improvements (driveways, utilities, landscaping,etc). Specific recommendations for excavations,fill placement,and foundation design for the proposed structures are presented in this report. The investigation for this report included field exploration, laboratory testing, geologic hazard evaluation, and engineering analysis, and preparation of this report. 1.2 Scope of Services The scope of services provided included: • Review of readily available geologic and soils reports pertinent to the site and adjacent areas. • Exploration of subsurface conditions to the depths influenced by the proposed construction. • Laboratory testing of representative soil samples to provide data to evaluate the geotechnical design characteristics of the soils. • Definition of the general geology and evaluation of potential geologic hazards at the site. - • Soil engineering design criteria for the proposed improvements. 0 Preparation of this summary report of the investigations performed including geotechnical construction recommendations. References cited in this report are presented in Appendix A. \\Cte_ser er\projects\10-7457G\Rpt_Geotechnical.doc _ Preliminary Geotechnical Investigation Page 2 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No. 10-7457G 2.0 SITE DESCRIPTION The site is located in the residential community of Cardiff by the Sea, at the corner of Birmingham Drive and Mackinnon Avenue. Presently,a single-story residence with a detached garage is situated on the site. This residence is surrounded be lawn,except for a concrete patio adjacent to the back of the house. It is our understanding that the existing residence will be demolished and replaced with the proposed three-story residential structure consisting of a two-story residence over a basement. Site elevations,from a site survey completed by Pasco Engineering,Inc.,range from approximately 220 feet above mean sea level in the southeast corner of the property to 218 feet above mean sea level in the northwest corner of the property. This equates to a slight west to northwest surface gradient across the site. Adjacent to Birmingham Drive the site is bounded by a two-to three foot retaining wall with an approximate 1.5 : 1 (H:V) slope from top wall to the lawn elevation(Figure - 2). This retaining and slope taper eastward and daylight with graded topography within the property limits. 3.0 FIELD AND LABORATORY INVESTIGATIONS 3.1 Field Investigation Our field exploration was conducted on January 5, 2005, and included a visual site reconnaissance and the excavation of three exploratory soil borings to evaluate the condition of the underlying soil materials. The borings were advanced within accessible areas of the subject site using a limited access drill rig equipped with continuous flight augers to the maximum explored depth of 16.5 feet \Tte_server\projects\l 0-7457G\Rpt_Geotechnica1.doc Preliminary Geotechnical Investigation Page 3 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No. 10-7457G below grade (fbg). Select undisturbed soil samples were collected using a modified California sampler and disturbed soil samples were collected with a Standard Penetration Test(SPT)sampler, Bulk samples were collected from drill cuttings and stored in burlap sample bags. Soils were logged in the field by a CTE geologist and visually classified according to the Unified Soil Classification System. Samples were transported to CTE Certified Geotechnical Laboratory in Escondido,California for analysis.The field descriptions have been modified,where appropriate,to reflect laboratory teat results. Exploration logs including descriptions of the soils encountered are included in Appendix B. Approximate exploration locations are shown on Figure 2. 3.2 Laboratory Investi ag tion Laboratory tests were conducted on representative soil samples for classification purposes and to evaluate physical properties and engineering characteristics. Soil samples were analyzed for Direct Shear, Particle-Size Analysis, Modified Proctor, Expansion Index Testing, In-Place Moisture and Density,and Chemical Analysis. Test method descriptions and laboratory test results are included in Appendix C. 4.0 GEOLOGY 4.1 General Setting Encinitas is located with the Peninsular Ranges physiographic province that is characterized by its -- northwest-trending mountain ranges, intervening valleys, and predominantly northwest trending active regional faults. The region can be further subdivided into the coastal plain area, a central \\Cte_server\projects\10-7457G\Rpt_Geotechnical.doc Preliminary Geotechnical Investigation Page 4 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No. 10-7457G mountain—valley area and the eastern mountain valley area. The project site is located within the coastal plain area. This subprovince ranges in elevation from approximately sea level to 1200 feet above mean sea level and is characterized by Cretaceous and Tertiary sedimentary deposits that onlap an eroded basement surface consisting of Jurassic and Cretaceous crystalline rocks. More specifically,the site lies on an uplifted marine terrace in an area characterized by westward sloping terraces incised by streams draining toward the Pacific Ocean. 4.2 Geologic Conditions Based on geologic mapping by Tan and Kennedy (1996), soils at the site consist of Quaternary Terrace Deposits that are correlative with the Quaternary Bay Point Formation. The soils encountered during our investigation consisted primarily of medium dense to very dense,moist,red- brown,orange-brown,brown, silty sand to hard sandy silt. A thin layer of loose,moist,dark brown topsoil was present in the lawn areas of the property. These findings are consistent with the mapping of Tan and Kennedy,and the soils are interrupted to be Quaternary Terrace Deposits of the Bay Point Formation. The nature and depth of basement rocks below the Quaternary Terrace Deposits are unknown. 4.2.1 Topsoils Topsoils were observed to a maximum depth of approximately two feet below existing grade -- in the area of B-2, and extended typically less than one-foot below grade throughout the remainder of the site. This soil consisted of loose to medium dense,moist,silty fine-grained SAND with abundant organics. These materials are not considered suitable for support of the \\Cte_server\projects\10-7457G\Rpt_GeotechnicaI doc Preliminary Geotechnical Investigation Page 5 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G proposed improvements primarily because of their high organic content. However, these materials are anticipated to be removed during construction grading activities for the proposed structures. Remaining amounts of these materials may be placed in non-structural landscape areas. 4.2.2 Quaternary Terrace Deposits Quaternary Terrace Deposits were observed underlying the topsoils. This material primarily consisted of medium dense to very dense,moist,red-brown,orange-brown,brown,silty fine- to medium-grained sand and some hard,moist,sandy silt. These materials were encountered to the maximum explored depth of 16.5 feet below existing grade.These soils are considered suitable for support of the proposed structure and the addition of fill,as recommended herein. 4.3 Groundwater Conditions Groundwater was not encountered in any of our borings to the maximum explored depth of 16.5 feet below existing grade. While groundwater conditions will likely vary, especially during periods of sustained precipitation,is not expected to affect the proposed improvements if proper site drainage is maintained. However, subdrains may be required based on our observations during grading and/or construction. 4.4 Geoloszic Hazards From our investigation it appears that geologic hazards at the site are primarily limited to those caused by violent shaking from earthquake generated ground motion waves. The potential for damage from displacement or fault movement beneath the proposed structures is considered low. \Tte_sever\projects\10-7457G\Rpt_Geotechnical.doc - Preliminary Geotechnical Investigation Page 6 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G 4.4.1 Local and Regional Faulting Based on our site reconnaissance,evidence from our exploratory soil borings, and a review of appropriate geologic literature, it is our opinion that no known fault traces underlie the site. Active offshore segments of the Rose Canyon fault are located approximately 7.5 kilometers from the site, and potentially active offshore segments of the Rose Canyon fault - system are located approximately four kilometers from the site (Jennings, 1994; Treiman, 1993). The Uniform Building Code(1997)considers the entire offshore Rose Canyon Fault System as an active near-source fault zone. We have adopted this interpretation in estimating distances to the nearest active fault;therefore,the four kilometer distance is considered the closest distance to an active fault from the site. Other principal active regional faults include the Elsinore, Coronado Banks, San Clemente, San Jacinto, and San Andreas faults. According to the California Division of Mines and Geology, a fault is zoned active if it displays evidence of activity in the last 11,000 years and potentially active if evidence of activity is between 1.8 million years to 11,000 years b.p. (Hart, 1994). 4.4.2 Site Near Source Factors and Seismic Coefficients In accordance with the California Building Code 2001 edition, Volume 2, Figure 16-2, the referenced site is located within seismic zone 4 and has a seismic zone factor of Z=0.4. The nearest active fault, the Rose Canyon Fault Zone, is approximately four kilometers to the west and is considered a Type B seismic source. Based on the distance from the site to the Rose Canyon Fault Zone,near source factors ofNv=1.33 and Na 1.1 are appropriate. Based \\Cte_server\projects\I 0-7457G\Rpt_Geotechnica1.doc Preliminary Geotechnical Investigation Page 7 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G on the shallow subsurface explorations and our knowledge of the area, the site has a soil profile type of SD and seismic coefficients of Cv=0.85 and Ca 0.48. 4.4.3 Liquefaction Evaluation -... Liquefaction occurs when saturated fine-grained sands or silts lose their physical strengths during earthquake induced shaking and behave as a liquid. This is due to loss of point-to-point grain contact and transfer of normal stress to the pore water. Liquefaction potential varies with water level,soil type,material gradation,relative density,and probable intensity and duration of ground shaking. Due to the absence of shallow groundwater condition and the medium dense to dense nature of the underlying native soils, it is our opinion that the potential for liquefaction should be considered low in all areas of the project. 4.4.4 Seismic Settlement Evaluation - Seismic settlement occurs when loose to medium dense granular soils densify during seismic events. We anticipate that loose surficial topsoils will be removed during grading. The underlying site materials were generally found to be dense and are not considered likely to experience significant seismic settlement. Therefore,in our opinion,the potential for seismic settlement resulting in damage to site improvements should be considered low. \\Cte_server\projects\10-7457G\Apt_Geotechnical.doc Preliminary Geotechnical Investigation Page 8 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G 4.4.5 Tsunamis Seiche and Flooding Evaluation The potential for tsunami damage at the site is very low due to the site's elevation(greater than 200 feet above sea level). Damage caused by oscillatory waves (seiche) is considered unlikely, as the site is not near any significant bodies of water that could produce such a phenomenon. 4.4.6 Landsliding or Rocksliding According to Tan and Giffen (1995), the site area is designated as generally susceptible to landsliding.However,no landslides have been mapped in the general area of the site,and no evidence of active landsliding was recognized during our site investigation. In addition,the site is mapped within an urbanized boundary and it appears that grading in the vicinity of the site has been properly performed. Therefore, the potential for landsliding or rocksliding to affect the site is considered remote. 4.4.7 Compressible and Expansive Soils Based on geologic observation,the observed Quaternary Terrace Deposits materials exhibit very low to low compressibility characteristics and are considered suitable for support of fill and improvements. Onsite materials were tested and determined to have an expansion index of zero, which corresponds to a material with very low or no expansion potential. Therefore,the presence of expansive materials will not affect the proposed development. \\Cte_smer\projects\I 0-7457G\Rpt_Geotechnical.doc Preliminary Geotechnical Investigation Page 9 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No 10-7457G 4.4.8 Corrosive Soils Analytical test results indicate that materials have a low potential to corrode Portland cement concrete. It also appears that materials have a low potential to corrode buried ferrous metals. A corrosion specialist shall be consulted for additional recommendations, if deemed necessary by the project coordinators or governing authority. 5.0 CONCLUSIONS AND RECOMMENDATIONS 5.1 General We conclude that the proposed construction on the site is feasible from a geotechnical standpoint, provided the recommendations in this report are incorporated into the design and construction of the project. Recommendations for the design and construction of the proposed improvements are presented in the subsequent sections of this report. 5.2 Site Preparation Before any grading occurs, the site should be cleared of existing debris and other deleterious materials. In areas to receive shallow founded structures or distress-sensitive improvements, all - topsoils, surficially eroded, desiccated, burrowed, or otherwise loose or disturbed soils should be removed to the depth of the competent native materials. CTE recommends the removal of the generally loose to medium dense and unsuitable high organic containing soils at the surface of the LL site. Organic and other deleterious materials not suitable for structural backfill should be disposed offsite at legal disposal site. Since basement improvements are proposed beneath the residential structure, overexcavation and recompaction is not required as all foundations will be extended to \Tte_server\projects\10-7457G\Rpt_Geotechnica1.doe - Preliminary Geotechnical Investigation Page 10 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G bear at depth in competent native materials. Thought not anticipated,proposed slab-on-grade areas may require scarification of nine to 12 inches and recompaction for uniform support at a minimum two percent above optimum moisture content. If slab-on-grade improvements are proposed near present grades,overexcavation and recompaction to competent native materials will be required. Organic or oversize materials (greater than three inches in maximum dimension) not suitable for structural backfill within three feet of proposed grade should be disposed of off-site or placed in non- structural planter or landscape areas. 5.3 Site Excavation _ .. Based on our observations, shallow excavations in site materials will generally be feasible with heavy-duty construction equipment under normal conditions. An engineer or geologist from CTE should evaluate the subgrade to verify that mitigative measures(removal of inadequate soils)have been properly carried out. Irreducible materials greater than three inches in maximum diameter were not identified in the preliminary investigation;however if such materials are encountered they should not be used in shallow fills (within three feet of proposed grades) on the site. In utility trenches, adequate bedding should surround pipes. 5.4 Fill Placement and Compaction The geotechnical consultant should verify that the proper site preparation has occurred before fill placement occurs. Following removal of any loose, disturbed soils, areas to receive fills or \\Cte_se"er\projects\10-7457G\Rpt_Geotechnical.doc _ Preliminary Geotechnical Investigation Page 11 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No 10-7457G improvements should be scarified nine inches,moisture conditioned, and properly compacted. Fill and backfill should be compacted to a minimum relative compaction of 90 percent(as evaluated by ASTM D1557) at moisture contents greater than two percent above optimum. The optimum lift thickness for backfill soil will be dependent on the type of compaction equipment used. Generally, backfill should be placed in uniform, horizontal lifts not exceeding eight inches in loose thickness. Backfill placement and compaction should be done in overall conformance with geotechnical recommendations and local ordinances. _ 5.5 Fill Materials The low to non-expansive soils derived from the onsite materials are considered suitable for reuse on the site as compacted fill. If used, these materials should be screened of organic materials and _ materials greater than three inches in a maximum dimension. If encountered, clayey, inorganic, native soils may be blended with granular soils and reused in non-structural fill areas. Imported fill beneath structures,pavements and walks should have an expansion index less than or equal to 30(per UBC 18-I-B)with less than 35 percent passing the no.200 sieve. Imported fill soils for use in structural or slope areas should be evaluated by the soils engineer to determine strength characteristics before placement on the site. 5.6 Temporary Construction Slopes Sloping recommendations for unshored temporary excavations are provided. The recommended slopes should be relatively stable against deep-seated failure, but may experience localized \\Cte_se,er\projects\10-7457G\Rpt_Geotechnical.doc Preliminary Geotechnical Investigation Page 12 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G sloughing. Onsite soils are considered Type B and Type C soils with recommended slope ratios as set forth in Table 1 below. TABLE 1 RECOMMENDED TEMPORARY SLOPE RATIOS SOIL TYPE SLOPE RATIO MAXIMUM HEIGHT (Horizontal: vertical) B (Formational Soils) 1:1 (MAXIMUM) 10 Feet C (Topsoils/Fills 1.5:1 (MAXIMUM) 10 Feet Actual field conditions and soil type designations must be verified by a "competent person" while excavations .exist according to Cal-OSHA regulations. In addition, the above sloping recommendations do not allow for surcharge loading at the top of slopes by vehicular traffic, equipment or materials. Appropriate surcharge setbacks must be maintained from the top of all unshored slopes. 5.7 Foundations and Slab Recommendations The following recommendations are for preliminary planning purposes only. These foundation recommendations should be reviewed after completion of earthworks. 5.7.1 Foundations Continuous and isolated spread footings are suitable for use at this site. However, footings should not straddle cut/fill interfaces; we anticipate all structural footings will be founded entirely upon competent native materials a minimum three feet below the lowest adjacent \\Cte_server\projects\10-7457G\Rpt_Geotechnical.doc Preliminary Geotechnical Investigation Page 13 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G exterior grade. Foundation dimensions and reinforcement should be based on allowable bearing values of 3,000 pounds per square foot (psf). The allowable bearing value may be increased by one third for short duration loading which includes the effects of wind or seismic forces. Footings should be at least 15 inches wide for two and three story improvements, and founded at least 36 inches below the lowest adjacent exterior subgrade. Reinforcement for continuous footings should consist of four#4 reinforcing bars;two placed near the top and two placed near the bottom. The structural engineer should provide recommendations for reinforcement of any deepened spread footings and footings with pipe penetrations. Foundation excavations shall generally be maintained at above optimum moisture content until concrete placement. 5.7.2 Foundation Settlement In general, for the proposed construction, the maximum post-construction compression settlement is expected to be less than 1.0 inch. Maximum differential settlement of continuous footings is expected to be on the order of 0.5 inches across the building. 5.7.3 Foundation Setback Footings for structures should be designed such that the horizontal distance from the face of adjacent slopes to the outer edge of the footing is a minimum of 10 feet. Excavations for Xte_ser er\project s\10-7457G\Rpt_Geotechnica1.doc Preliminary Geotechnical Investigation Page 14 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G utility trenches within 10 lateral feet should not encroach within a 1:1 plane extending downward from the closest bottom edge of adjacent footings. 5.7.4 Interior Concrete Slabs Lightly loaded concrete slabs should be designed for the anticipated loading, but be a minimum of 4.5 inches thick. Minimum slab reinforcement should consist of#3 reinforcing bars placed on 18-inch centers, each way at mid-slab height. In moisture sensitive floor areas, a vapor barrier of ten-mil visqueen (with all laps sealed or taped), overlying a maximum two-inch layer of consolidated aggregate base (Sand Equivalent greater than 30) shall be installed. A one- to two-inch layer of similar material may be placed above the visqueen to protect the membrane during steel or concrete placement. Slab areas subject to heavier than typical vehicular loads may require increased thickness and reinforcement. This office should be contacted to provide additional recommendations where actual service conditions warrant further analysis. Subgrade materials shall be maintained at slightly above optimum moisture content until slab underlayment or concrete are placed. 5.8 Lateral Resistance and Earth Pressures The following recommendations may be used for shallow footings on the site. Foundations placed in firm, well-compacted fill material may be designed using a coefficient of friction of 0.30 (total _ frictional resistance equals coefficient of friction times the dead load). A design passive resistance value of 300 pounds per square foot per foot of depth(with a maximum value of 1500 pounds per square foot)may be used. The allowable lateral resistance can be taken as the sum of the frictional \\Cte_se"er\projects\10-745 7G\Rpt_Geotechnica1.doc Preliminary Geotechnical Investigation Page 15 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G resistance and the passive resistance,provided the passive resistance does not exceed two-thirds of the total allowable resistance. Retaining walls up to 10 feet high and backfilled using granular soils may be designed using the equivalent fluid weights given in Table 2 below. TABLE 2 EQUIVALENT FLUID UNIT WEIGHTS (pounds per cubic foot WALL TYPE LEVEL BACKFILL SLOPE BACKFILL 2:1 (HORIZONTAL: VERTICAL) CANTILEVER WALL 35 60 (YIELDING) RESTRAINED WALL 55 90 The values above assume non-expansive backfill and free draining conditions. Measures should be taken to prevent moisture buildup behind all retaining walls. Drainage measures should include free draining backfill materials and perforated drains. These drains should discharge to an appropriate offsite location. Basement wall waterproofing shall be as per the project architect. 5.9 Exterior Flatwork To reduce the potential for distress to exterior flatwork caused by minor settlement of foundation soils,we recommend that such flatwork be installed with crack-control joints at appropriate spacing as designed by the project architect. Additionally,we recommend that flatwork be installed with at least minimal reinforcement. Flatwork,which should be installed with crack control joints,includes driveways,sidewalks,and architectural features. All subgrades should be prepared according to the \\Cte_se-er\projects\I 0-7457G\Rpt_Geotechnica1.doc Preliminary Geotechnical Investigation Page 16 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California - February 14, 2005 CTE Job No 10-7457G earthwork recommendations previously given before placing concrete. Positive drainage should be established and maintained next to all flatwork. Subgrade materials shall be maintained at slightly above optimum moisture content until concrete placement. 5.10 Drainage Surface runoff should be collected and directed away from improvements by means of appropriate erosion reducing devices and positive drainage should be established around the proposed improvements. Positive drainage should be directed away from improvements at a gradient of at least two percent for a distance of at least five feet. The project civil engineers should evaluate the on-site drainage and make necessary provisions to keep surface water from affecting the site. 5.11 Slopes Significant slopes are not anticipated at the site. Based on anticipated soil strength characteristics, fill slopes should be constructed at slope ratios of 2:1 (horizontal: vertical)or flatter. These fill slope inclinations should exhibit factors of safety greater than 1.5. Although properly constructed slopes on this site should be grossly stable,the soils will be somewhat erodible. Therefore, runoff water should not be permitted to drain over the edges of slopes unless that water is confined to properly designed and constructed drainage facilities. Erosion resistant vegetation should be maintained on the face of all slopes. \\Cte_Smer\proj ects\10-7457G\Rpt_Geotechnica1.doc Preliminary Geotechnical Investigation Page 17 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G Typically, soils along the top portion of a fill slope face will creep laterally. We do not recommend distress sensitive hardscape improvements be constructed within five feet of slope crests in fill areas or that thickened edges be employed. 5.12 Construction Observation The recommendations provided in this report are based on preliminary design information for the proposed construction and the subsurface conditions found in the exploratory boring locations. The interpolated subsurface conditions should be checked in the field during construction to verify that conditions are as anticipated. Recommendations provided in this report are based on the understanding and assumption that CTE will provide the observation and testing services for the project. All earthwork should be observed and tested to verify that grading activity has been performed according to the recommendations contained within this report. The project engineer should evaluate all footing trenches before reinforcing steel placement. 5.13 Plan Review CTE should review the project foundation plans and grading plans before commencement of earthwork to identify potential conflicts with the recommendations contained in this report. \\Cte_se-er\projects\10-7457G\Rpt_Geotechnical.doc Preliminary Geotechnical Investigation Page 18 Proposed Strebe Residence 525 Birmingham Drive, Encinitas, California February 14, 2005 CTE Job No 10-7457G 6.0 LIMITATIONS OF INVESTIGATION The field evaluation, laboratory testing and geotechnical analysis presented in this report have been conducted according to current engineering practice and the standard of care exercised by reputable geotechnical consultants performing similar tasks in this area. No other warranty, expressed or implied,is made regarding the conclusions,recommendations and opinions expressed in this report. Variations may exist and conditions not observed or described in this report may be encountered during construction. Our conclusions and recommendations are based on an analysis of the observed conditions. If conditions different from those described in this report are encountered,our office should be notified and additional recommendations, if required, will be provided upon request. We appreciate this opportunity to be of service on this project. If you have any questions regarding this report,please do not hesitate to contact the undersigned. Respectfully submitted, CONST ESTING & ENGINEERING, INC. �,\ONAL Dan T. Math, RCE# 61013 _ Martin Siem CEG#2311 O'*ART Senior Engineer Quo �Certified Engineering Geologis ° CERTIF < L j X 714 EPd!3,`d� GEO rt.;,5;: rxp, CO No.2665 m Exp: 12/31/08 \\Cte_smer\projects\10-7457GMpt_Geotechnical.doc !1.9� (.,1":T-,1 n; I.•:1 r fI-"Gi :.I r, nl rl IF -•I.TI.I, _._. _ _ _.., ..'.. -iii •��411J c_I;V:i.,w� r mtxw arr F i STA't�86Aff/ Std Eldeinitas Ism 911 c E. Uf S 2 I � or t ) r sJ�vG rc.l -J.�i\r".+ y rkr:�t ! '' • \" 'r'°• �; -. n-.1 S ? APPROXIMATE Y r SITE LOCATION 1 x a } m _ Z Cardiff-by.the-.Seap a fi� ��QJlji ar y �� (cm-diff) f 4: -- 5'OldttB Be acb J �! ryN I) r`iz� �., �(`,, � z � } „}(1, • I� a ''�� ;,� � "' S } Y• y I�y STY: -' S ' - 11?.:.FF °Vp •wv'958411?.2SOn.1 w; Ir - I t fin;, Ik o.,III,«M11:•'-I I t hrn..i s f li cnr.� °K CONSTRUCTION TESTING 8-1 ENGINEERING, INC. V°?r' r- Ib.Ill?IINI("\1.ANI7(ON STR(!(:IIONENGIN CERIti(:TESi[NGANDINSPECTION 7iRING.INC '_414 V INE1:ARD-AA ENUL,STE G ESC'ONDIDO CA.92029(7601 716-49 5 5 EVGINI SITE INDEX MAP cTE,o6 N 10-7457G PROPOSED STREBE RESIDENCE 7C A"7 AS SHOWN 525 BIRMINGHAM DRIVE �, FIGURE.: 1 C:1RUIPE-BY=1'IiE-51:;1,CALIFORNIA D-6 /05 w Z oo Ipy g �k+ 9 Cl- CO yf� a �"" mF 3115 ► Z I R C m 2y a N N C� Of �i < W o w � m is �� C LLI �i U p W h U In J s3 <� d rQQ�s a WK 3 O n d d W � gq<'� C� $ Sr1 Li `q� k' O i Hvn,i0i i>f O Q �" Q �i m �W� J u«'61�5� tZ `a ai o Z W z _ o O O �Q] I=U fU KS h ;O O HISON 0! i o v '1O G lJ Ha d J z 6j OC �� Li r b of Ix Oe ~ C �D J z z Of} h W W W O t W a Q Q d vi U OO O Q V CL 1 � 3 ' C55 1 I � 1 I I b -�/ AN fhb �y 1L \\ �y N F�1 .trzc 3.zl,was N CL o R , W L1— m ti to Q 1 9 Fb5�l 1 z Ll CJ O1 � n � LL 2ta W ~ .00 9z R F b 4ti R VJ 30 AIAm3115Y3 i,IL 3MQJ } }� o y }% b ti i 1 1 AB'001�I.L(I.BB.BfN z r— o U APPENDIX A REFERENCES CITED REFERENCES CITED 1. Hart, Earl W., Revised 1994, "Fault-Rupture Hazard Zones in California, Alquist Priolo, Special Studies Zones Act of 1972," California Division of Mines and Geology, Special Publication 42. - 2. Jennings, Charles W., revised 1987, "Fault Map of California with Locations of Volcanoes, Thermal Springs and Thermal Wells." 3. Tan, S. S., and Giffen, 1995, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County,California:Landslide Hazard Identification Map No. 35", California Department of Conservation, Division of Mines and Geology, Open-File -" Report 95-04, State of California, Division of Mines and Geology, Sacramento, California. 4. Tan, S. S., and Kennedy, 1996, "Geologic Map of the Encinitas and Rancho Santa Fe 7.5 Minute Quadrangles, San Diego County, California", California Department of Conservation,Division of Mines and Geology,Open-File Report 96-02,State of California, Division of Mines and Geology, Sacramento, California. APPENDIX B EXPLORATION LOGS ;4CONSTRUCTION TESTING & ENGINEERING, INC, Gp' GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION 2414 VINEYARD AVENUE, SUITE G ESCONDIDO CA. 92029 (760)746-4955 ENOWEERQPG,AC, DEFINITION OF TERMS PRIMARY DIVISIONS SYMBOLS SECONDARY DIVISIONS GRAVELS CLEAN ? GW �. WELL GRADED GRAVELS,GRAVEL-SAND MIXTURES MORE THAN GRAVELS - LITTLE OR NO FINES.77111 Z HALF OF <5%FINES v POORLY GRADED GRAVELS OR GRAVEL SAND MIXTURES, w COARSE GP ' LITTLE OF NO FINES . ... .. . .. .. . . 00 FRACTION IS SILTY GRAVELS,GRAVEL-SAND-SILT MIXTURES, A a w LARGER THAN GRAVELS GM39 w WITH FINES NON-PLASTIC FINES x ¢ , NO.4 SIEVE GC CLAYEY GRAVELS,GRAVEL-SAND-CLAY MIXTURES, Z a vwi _ PLASTIC FINES t� o SANDS CLEAN _jr-+S W :� WELL GRADED SANDS,GRAVELLY SANDS,LITTLE OR NO W O o MORE THAN SANDS _ : FINES HALF OF <5%FINES <`=''' sP,,,j+ J` POORLY GRADED SANDS,GRAVELLY SANDS,LITTLE OR O z COARSE °'`' NO FINES U FRACTION IS SM SILTY SANDS,SAND-SILT MIXTURES,NON-PLASTIC FINES SMALLER THAN SANDS - WITH FINES NO.4 SIEVE SC`:! CLAYEY SANDS,SAND-CLAY MIXTURES,PLASTIC FINES INORGANIC SILTS,VERY FINE SANDS,ROCK FLOUR,SILTY d O a SILTS AND CLAYS ML OR CLAYEY FINE SANDS,SLIGHTLY PLASTIC CLAYEY SILTS O a LIQUID LIMIT IS CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, A LESS THAN 50 GRAVELLY,SANDY,SILTS OR LEAN CLAYS E, z 4 OL ORGANIC SILTS AND ORGANIC CLAYS OF LOW PLASTICITY a O MH INORGANIC SILTS,MICACEOUS OR DIATOMACEOUS FINE z SILTS AND CLAYS SANDY OR SILTY SOILS,ELASTIC SILTS Z LIQUID LIMIT IS CH INORGANIC CLAYS OF HIGH PLASTICITY,FAT CLAYS GREATER THAN 50 ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, OH ORGANIC SILTY CLAYS HIGHLY ORGANIC SOILS PT PEAT AND OTHER HIGHLY ORGANIC SOILS GRAIN SIZES BOULDERS COBBLES GRAVEL SAND COARSE FINE COARSE MEDIUM FIlVE SILTS AND CLAYS 12" 3" 3/4" 4 10 40 200 CLEAR SQUARE SIEVE OPENING U.S. STANDARD SIEVE SIZE ADDITIONAL TESTS (OTHER THAN TEST PIT AND BORING LOG COLUMN HEADINGS) MAX-Maximum Dry Density PM-Permeability PP-Pocket Penetrometer GS- Grain Size Distribution SG-Specific Gravity WA-Wash Analysis SE-Sand Equivalent HA-Hydrometer Analysis y DS-Direct Shear EI-Expansion Index AL-Atterberg Limits RDS-Repeated Direct Shear CHM-Sulfate and Chloride RV-R-Value UC-Unconfined Compression m Content,pH,Resistivity CN-Consolidation MD-Moisture/Density COR-Corrosivity CP-Collapse Potential M-Moisture SD-Sample Disturbed HC-Hydrocollapse SC-Swell Compression REM-Remolded OI-Organic Impurities FIGUEfff BL 1 0 hO$ 'CONSTRUCTION TESTING & ENGINEERING, INC. O GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION `Ot Qe 2414 VINEYARD AVENUE. SUITE G ESCONDIDO CA.92029 (760)746-4955 HNCINPERQ4G,AIC. PROJECT: DRILLER: CTE JOB NO: SHEET: of DRILL METHOD: DRILLING DATE: LOGGED BY: SAMPLE METHOD: ELEVATION: BORING LEGEND Laboratory Tests w Q N N h a � o A U DESCRIPTION 0 Block or Chunk Sample Bulk Sample FS Standard Penetration Test -1 Modified Split-Barrel Drive Sampler(Cal Sampler) rThin Walled Army Corp. of Engineers Sample ^�15 Groundwater Table r __________________________________________ Soil Type or Classification Change Formation Change l(Approximate boundaries queried MI ,.sm" Quotes are placed around classifications where the soils L25 exist in situ as bedrock FIGURE: BL2 'CONSTRUCTION TESTING & ENGINEERING, INC. GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION C 2414 VINEYARD AVENUE. SUITE G ESCONDIDO CA. 92029 (760) 746-4955 EI�GINEERQCG.LVC PROJECT: STREBE RESIDENCE DRILLER: SOUTH COAST SHEET: I of 1 CTE JOB NO: 10-7457G DRILL METHOD: LIMITED ACESS-CONT FLIGHT DRILLING DATE: 1/5/2005 LOGGED BY: MES SAMPLE METHOD: DRIVE MOD CAL&SPT ELEVATION: 218 Laboratory Tests and y BORING: B-1 a x > 3 Q y a Continents 0 DESCRIPTION 0 Lawn covered area 2-3 me es o awn an to soi . Hand Angered BAY POINT FORMATION: to 2.0' Loose,wet,brown, silty SAND(SM),fine-grained sand. EI 2 CHEM 2 3 _ 5 1 Increasing sand%and grain size of SAND fnIe-to-medium Driller reports 1 grained SAND,orange-brown. firming drilling at 3 approx 8' 1 8 Medium dense,moist,orange-brown, fine-grained silty SAND 10 (SM). 13 r► Becomes gray. rReturns to orange brown,becomes very dense. - 1 34 TI 46 59 Total Depth 16.5 on 115105 No Groundwater Observed Backfilled with Native Soil 2 2 Boring B-1 ^� ONSTRUCTION TESTING & ENGINEERING, INC. GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION 2414 VINEYARD AVENUE. SUITE G ESCONDIDO CA 92029 (76n) 746.4955 ENGINEERING,LVC PROJECT: STREBE RESIDENCE DRILLER: SOUTH COAST SHEET: 1 of 1 CTE JOB NO: 10-7457G DRILL METHOD: LIMITED ACESS-CONT FLIGHT DRILLING DATE: 1/5/2005 LOGGED BY: MES SAMPLE METHOD: DRIVE MOD CAL&SPT ELEVATION: 219.6 ry Tests and Laboratory BORING. B-2 w c Q N a Comments 0 DESCRIPTION 0 Lawn an to sot . Loos—e—Aark brown,wet s1 ity SAND. Hand Augere to 2.0' 1 BAY POINT FORMATION• 2 Loose,moist,dark brown to brown,fine-to-meidum grained 3 silty SAND(SM). A-horizon soil developed on upper portions of formational sands. 5 Medium dense to dense, light orange-brown,medium-grained silty SAND(SM). --------------------------------------------------- Driller Reports firmer drilling at 6' MD,DS 13 Very dense,moist,red-brown,fine-to-medium grained silty 22 SAND(SM),weakly developed soil with translocated clays. 1 46 Driller reports harder drilling,augers binding as if in clays. 24 ♦ Becomes mottled red-brown with yellowish gray, irregular 1 50 sha ed sand infillin ossi le burrows? Total Depth 15' on 115105 No Groundwater observed Backfilled with Native Soil 2 2 ;CONSTRUCTION TESTING & ENGINEERING, INC. 5�r 2Q GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION 2414 VINEYARD AVENUE. SUITE G ESCONDIDO CA. 92029 (760)746_4955 ENGR4EERINGiVC PROJECT: STREBE RESIDENCE DRILLER: SOUTH COAST SHEET: 1 of 1 CTE JOB NO: 10-7457G DRILL METHOD: LIMITED ACESS-CONT FLIGHT DRILLING DATE: 1/5/2005 LOGGED BY: MES SAMPLE METHOD: DRIVE MOD CAL&SPT ELEVATION: 220 c a• BORING: B-3 Laboratory Tests and t ° y Q 'Ei U s Comments DESCRIPTION 0 DIrt rrveiav lops0il loosejurk brown,sil AND(SM). Hand Angered BAY POINT FORMATION• to 2.0' Loose,moist,grayish-brown,silty SAND(SM). ------------------------------------------------------Drillerreportsfirm- very firm soil Hard,dry, light brown with slight yellow and reddish tint, sandy 3 to 3.5'. 5 20 SILT. 26 El 27 TI 50/3" Total Depth 8.5' 1 No Groundwater Observed Backfilled with Native 1 2 2 APPENDIX C LABORATORY METHODS AND RESULTS APPENDIX C LABORATORY METHODS AND RESULTS Laboratory Testing Program Laboratory tests were performed on representative soil samples to detect their relative engineering properties. Tests were performed following test methods of the American Society for Testing Materials or other accepted standards. The following presents a brief description of the various test methods used. Classification Soils were classified visually according to the Unified Soil Classification System. Visual classifications were supplemented by laboratory testing of selected samples according to ASTM D2487. The soil classifications are shown on the Exploration Logs in Appendix B. Expansion Index Expansion testing may have been performed on selected samples of the matrix of the onsite soils according to Building Code Standard No.29-2. Expansion Index results is reported in Appendix C. Chemical Analysis Soil materials were collected with sterile sampling equipment and tested for Sulfate and Chloride content, pH, Corrosivity, and Resistivity. �CONSTRUCTION TESTING & ENGINEERING, INC. ' GEOTECHNICAL AND CONSTRUCTION ENGINEERING TESTING AND INSPECTION yo � 2414 VINEYARD AVENUE.SUITE G ESCONDIDO CA. 92029(760)746-4955 EMMERR:G.LNC EXPANSION INDEX TEST - UBC 18-2 LOCATION DEPTH EXPANSION INDEX EXPANSION (feet) POTENTIAL B-I 0.0 to 3.0 0 VERY LOW B-3 3.0 to 5.0 0 VERY LOW IN-PLACE MOISTURE AND DENSITY LOCATION DEPTH %MOISTURE DRY DENSITY (feet) B-2 8.5 to 10.0 15.7 116.3 - SULFATE LOCATION DEPTH RESULTS - (feet) ppm B-1 5.0 to 6.5 75 CHLORIDE LOCATION DEPTH RESULTS (feet) ppm B-1 5.0 to 6.5 18 CONDUCTIVITY CALIFORNIA TEST 424 LOCATION DEPTH RESULTS (feet) us/cm B-I 5.0 to 6.5 78 RESISTIVITY CALIFORNIA TEST 424 LOCATION DEPTH RESULTS (feet) ohms/cm B-I 5.0 to 6.5 10800 LABORATORY SUMMARY CTE JOB NO. 10-7457G 0 I � _ — I, ---i ------ ---- - - - o O i � I E ooz W 001 I I O UD UD 09 --- � E Ob Q w W N Z o£ - U v� OZ a C6 91 - - Z W 8 -- z o F-- � zo - ' • ` < 4 f- O O O F - - _F _.- ___I- - - z o O O O p C O O O O 00 O O O N O O (%)DMSSVd.LN133Hdd .tio d 0 000 PRECONSOLIDATION SHEARING DATA 5000 0.005 0.010 4000 0.015 d Q v 0 020 W _ U) 3000 — w Z 0 025 Of H Q 0 030 2000 � Q N 0 035 w S U) 0.040 1000 0.045 - /7 _._ 0.050 0 0 2 4 6 8 10 12 14 16 18 20 0.1 1 10 100 1000 TIME(minutes) VERTICAL STRESS 1000 psf STRAIN(%) 3000 psf qnnn - FAILURE ENVELOPE 5000 4000 a 3000 - w H to 0 z a 2000 w cn 1000 d,=0.02 mm./min 0 0 1000 2000 3000 4000 5000 VERTICAL STRESS(psf) SHEAR STRENGTH TEST Sample Desi nation De th(ft) Cohesion An le of Friction Sample Description B-Z 8.5-10' 60 sf 34.0 Initial Moisture (%): 7.6% initial Dry Densit (pcf 15.7 Undisturbed Orange-Brown Silty Sand Final Moisture (%): 125.1% Final Dr Densti ) CTE JOB NO: (0C-2 Y y (pcf) 116.3 FIGURE No: C-2 _ _ _ _ APPENDIX D STANDARD SPECIFICATIONS FOR GRADING ' _ _ _ _ _ - - _ _ - Appendix D Standard Grading Specifications Page D-1 Section 1 - General The guidelines contained herein represent Construction Testing & Engineering's standard recommendations for grading and other associated operations on construction projects. These guidelines should be considered a portion of the project specifications. Recommendations contained in the body of the previously presented soils report shall supersede the recommendations and or requirements as specified herein. The project geotechnical consultant shall interpret disputes arising - out of interpretation of the recommendations contained in the soils report or specifications contained herein. - Section 2 - Responsibilities of Project Personnel The geotechnical consultant should provide observation and testing services sufficient to assure that geotechnical construction is performed in general conformance with project specifications and standard grading practices. The geotechnical consultant should report any deviations to the client or his authorized representative. The Client should be chiefly responsible for all aspects of the project. He or his authorized representative has the responsibility of reviewing the findings and recommendations of the geotechnical consultant. He shall authorize or cause to have authorized the Contractor and/or other consultants to perform work and/or provide services. During grading the Client or his authorized representative should remain on-site or should remain reasonably accessible to all concerned parties in order to make decisions necessary to maintain the flow of the project. The Contractor should be responsible for the safety of the project and satisfactory completion of all grading and other associated operations on construction projects,including,but not limited to,earth work in accordance with the project plans, specifications and controlling agency requirements. Section 3 - Preconstruction Meeting A preconstruction site meeting shall be arranged by the owner and/or client and shall include the grading contractor, the design engineer, the geotechnical consultant, owner's representative and representatives of the appropriate governing authorities. Section 4 - Site Preparation The client or contractor should obtain the required approvals from the controlling authorities for the project prior, during and/or after demolition, site preparation and removals, etc. The appropriate approvals should be obtained prior to proceeding with grading operations. Clearing and grubbing should consist of the removal of vegetation such as brush, grass, woods, stumps, trees, root of trees and otherwise deleterious natural materials from the areas to be graded. Clearing and grubbing should extend to the outside of all proposed excavation and fill areas. \CTE SERVERIPROIECT 10445]G'RPT GFOTECIINICM_p Appendix D Standard Grading Specifications Page D-2 Demolition should include removal of buildings, structures, foundations, reservoirs, utilities (including underground pipelines, septic tanks, leach fields, seepage pits, cisterns, mining shafts, tunnels,etc.)and other man-made surface and subsurface improvements from the areas to be graded. Demolition of utilities should include proper capping and/or rerouting pipelines at the project perimeter and cutoff and capping of wells in accordance with the requirements of the governing authorities and the recommendations of the geotechnical consultant at the time of demolition. Trees, plants or man-made improvements not planned to be removed or demolished should be protected by the contractor from damage or injury. Debris generated during clearing, grubbing and/or demolition operations should be wasted from areas to be graded and disposed off-site. Clearing, grubbing and demolition operations should be performed under the observation of the geotechnical consultant. Section 5 - Site Protection Protection of the site during the period of grading should be the responsibility of the contractor. Unless other provisions are made in writing and agreed upon among the concerned parties, completion of a portion of the project should not be considered to preclude that portion or adjacent areas from the requirements for site protection until such time as the entire project is complete as identified by the geotechnical consultant, the client and the regulating agencies. Precautions should be taken during the performance of site clearing, excavations and grading to protect the work site from flooding, ponding or inundation by poor or improper surface drain e. away from and o Temporary provisions should be made during the rainy season to adequately direct surface drainage ag off the work site. Where low areas cannot be avoided,p to continually remove water during periods of rainfall. umps should be kept on hand Rain related damage should be considered to include, but may not be limited to, erosion, silting, saturation, swelling, structural distress and other adverse conditions as determined by the - geotechnical consultant. Soil adversely affected should be classified as unsuitable materials and should be subject to overexcavation and replacement with compacted fill or other remedial grading as recommended by the geotechnical consultant. The contractor should be responsible for the stability of all temporary excavations. Recommendations by the geotechnical consultant pertaining to temporary excavations e. backcuts) are made in consideration of stability of the completed project and,therefore, should of be considered to preclude the responsibilities of the contractor. Recommendations by the geotechnical consultant should not be considered to preclude requirements that are more restrictive by the regulating agencies. The contractor should provide during periods of extensive rainfall plastic sheeting to prevent unprotected slopes from becoming saturated and unstable. When deemed appropriate by the geotechnical consultant or governing agencies the contractor shall install I�CTE SERVER,PROJECT5,10-]45)G,RPT.GEOI'ECIINICMA. Appendix D Standard Grading Specifications Page D-3 checkdams, desilting basins, sand bags or other drainage control measures. In relatively level areas and/or slope areas,where saturated soil and/or erosion gullies exist to depths of greater than 1.0 foot; they should be overexcavated and replaced as compacted fill in accordance with the applicable specifications. Where affected materials exist to depths of 1.0 foot or less below - proposed finished grade,remedial grading by moisture conditioning in-place,followed by thorough recompaction in accordance with the applicable grading guidelines herein may be attempted. If the desired results are not achieved, all affected materials should be overexcavated and replaced as compacted fill in accordance with the slope repair recommendations herein. If field conditions dictate, the geotechnical consultant may recommend other slope repair procedures. Section 6 -Excavations 6.1 Unsuitable Materials Materials that are unsuitable should be excavated under observation and recommendations of the geotechnical consultant. Unsuitable materials include, but may not be limited to, dry, loose, soft, wet, organic compressible natural soils and fractured, weathered, soft bedrock and nonengineered or otherwise deleterious fill materials. Material identified by the geotechnical consultant as unsatisfactory due to its moisture conditions should be overexcavated; moisture conditioned as needed, to a uniform at or above optimum moisture condition before placement as compacted fill. If during the course of grading adverse geotechnical conditions are exposed which were not anticipated in the preliminary soil report as determined by the geotechnical consultant additional exploration, analysis, and treatment of these problems may be recommended. 6.2 Cut Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent cut slopes should not be steeper than 2:1 (horizontal: vertical). The geotechnical consultant should observe cut slope excavation and if these excavations W expose loose cohesionless, significantly fractured or otherwise unsuitable material, the materials should be overexcavated and replaced with a compacted stabilization fill. If encountered specific cross section details should be obtained from the Geotechnical Consultant. When extensive cut slopes are excavated or these cut slopes are made in the direction of the prevailing drainage, a non-erodible diversion swale (brow ditch) should be provided at the top of the slope. "CTE_SERVER,PRWECTSk 10.74570 RPT GLGTECHNICA.IX Appendix D Page D-4 Standard Grading Specifications 6.3 Pad Areas All lot pad areas, including side yard terrace containing both cut and fill materials, - transitions, located less than 3 feet deep should be overexcavated to a depth of 3 feet and replaced with a uniform compacted fill blanket of 3 feet. Actual depth of overexcavation may vary and should be delineated by the geotechnical consultant during grading. For pad areas created above cut or natural slopes, positive drainage should be established away from the top-of-slope. This may be accomplished utilizing a berm drainage swale and/or an appropriate pad gradient. A gradient in soil areas away from the top-of-slopes of 2 percent or greater is recommended. Section 7 - Compacted Fill All fill materials should have fill quality, placement, conditioning and compaction as specified below or as approved by the geotechnical consultant. 7.1 Fill Material Quality Excavated on-site or import materials which are acceptable to the geotechnical consultant may be utilized as compacted fill,provided trash,vegetation and other deleterious materials are removed prior to placement. All import materials anticipated for use on-site should be sampled tested and approved prior to and placement is in conformance with the requirements outlined. Rocks 12 inches in maximum and smaller may be utilized within compacted fill provided sufficient fill material is placed and thoroughly compacted over and around all rock to effectively fill rock voids. The amount of rock should not exceed 40 percent by dry weight passing the 3/4-inch sieve. The geotechnical consultant may vary those requirements as field conditions dictate. Where rocks greater than 12 inches but less than four feet of maximum dimension are generated during grading,or otherwise desired to be placed within an engineered fill,special handling in accordance with the recommendations below. Rocks greater than four feet should be broken down or disposed off-site. 7.2 Placement of Fill Prior to placement of fill material, the geotechnical consultant should inspect the area to receive fill. After inspection and approval,the exposed ground surface should be scarified to a depth of 6 to 8 inches. The scarified material should be conditioned(i.e.moisture added or air dried by continued discing) to achieve a moisture content at or slightly above optimum moisture conditions and compacted to a minimum of 90 percent of the maximum density or as otherwise recommended in the soils report or by appropriate government agencies. - Compacted fill should then be placed in thin horizontal lifts not exceeding eight inches in ,CTE_SERVER PROJLC"fSI l0.)MRPT GEOTECHNIC.LL NK Appendix D Standard Grading Specifications Page D-5 loose thickness prior to compaction. Each lift should be moisture conditioned as needed, thoroughly blended to achieve a consistent moisture content at or slightly above optimum - and thoroughly compacted by mechanical methods to a minimum of 90 percent of laboratory maximum dry density. Each lift should be treated in a like manner until the desired finished grades are achieved. The contractor should have suitable and sufficient mechanical compaction equipment and watering apparatus on the job site to handle the amount of fill being placed in consideration of moisture retention properties of the materials and weather conditions. When placing fill in horizontal lifts adjacent to areas sloping steeper than 5:1 (horizontal: vertical), horizontal keys and vertical benches should be excavated into the adjacent slope area. Keying and benching should be sufficient to provide at least six-foot wide benches and a minimum of four feet of vertical bench height within the firm natural ground,firm bedrock or engineered compacted fill. No compacted fill should be placed in an area after keying and benching until the geotechnical consultant has reviewed the area. Material generated by the benching operation should be moved sufficiently away from the bench area to allow for the recommended review of the horizontal bench prior to placement of fill. Within a single fill area where grading procedures dictate two or more separate fills, temporary slopes (false slopes)may be created. When placing fill adjacent to a false slope, benching should be conducted in the same manner as above described. At least a 3-foot vertical bench should be established within the firm core of adjacent approved compacted fill prior to placement of additional fill. Benching should proceed in at least 3-foot vertical increments until the desired finished grades are achieved. Prior to placement of additional compacted fill following an overnight or other grading delay, the exposed surface or previously compacted fill should be processed by scarification, moisture conditioning as needed to at or slightly above optimum moisture content, thoroughly blended and recompacted to a minimum of 90 percent of laboratory maximum dry density. Where unsuitable materials exist to depths of greater than one foot, the unsuitable materials should be over-excavated. Following a period of flooding, rainfall or overwatering by other means, no additional fill should be placed until damage assessments have been made and remedial grading performed as described herein. Rocks 12 inch in maximum dimension and smaller may be utilized in the compacted fill provided the fill is placed and thoroughly compacted over and around all rock. No oversize material should be used within 3 feet of finished pad grade and within 1 foot of other compacted fill areas. Rocks 12 inches up to four feet maximum dimension should be placed below the upper 5 feet of any fill and should not be closer than 11 feet to any slope face. These recommendations could vary as locations of improvements dictate. Where practical, cm SERVER 17G'•RPl_GEOTECII\IC,V DGC Appendix D Standard Grading Specifications Page D-6 oversized material should not be placed below areas where structures or deep utilities are proposed. Oversized material should be placed in windrows on a clean, overexcavated or unyielding compacted fill or firm natural ground surface. Select native or imported granular soil (S.E. 30 or higher) should be placed and thoroughly flooded over and around all windrowed rock, such that voids are filled. Windrows of oversized material should be staggered so those successive strata of oversized material are not in the same vertical plane. It may be possible to dispose of individual larger rock as field conditions dictate and as recommended by the geotechnical consultant at the time of placement. The contractor should assist the geotechnical consultant and/or his representative by digging test pits for removal determinations and/or for testing compacted fill. The contractor should provide this work at no additional cost to the owner or contractor's client. Fill should be tested by the geotechnical consultant for compliance with the recommended relative compaction and moisture conditions. Field density testing should conform to ASTM - Method of Test D 1556-82, D 2922-81. Tests should be conducted at a minimum of 2 vertical feet or 1,000 cubic yards of fill placed. Actual test intervals may vary as field conditions dictate. Fill found not to be in conformance with the grading recommendations should be removed or otherwise handled as recommended by the geotechnical consultant. 7.3 Fill Slopes Unless otherwise recommended by the geotechnical consultant and approved by the regulating agencies, permanent fill slopes should not be steeper than 2:1 (horizontal: vertical). Except as specifically recommended in these grading guidelines compacted fill slopes should be over-built and cut back to grade,exposing the firm,compacted fill inner core. The actual amount of overbuilding may vary as field conditions dictate. If the desired results are not achieved,the existing slopes should be overexcavated and reconstructed under the guidelines of the geotechnical consultant. The degree of overbuilding shall be increased until the desired compacted slope surface condition is achieved. Care should be taken by the contractor to provide thorough mechanical compaction to the outer edge of the overbuilt slope surface. At the discretion of the geotechnical consultant,slope face compaction may be attempted by -- conventional construction procedures including backrolling. The procedure must create a firmly compacted material throughout the entire depth of the slope face to the surface of the previously compacted firm fill intercore. During grading operations,care should be taken to extend compactive effort to the outer edge of the slope. Each lift should extend horizontally to the desired finished slope surface or more as needed to ultimately established desired grades. Grade during construction should ,�CTE,SERVER,PROXCTS,10-7457GRPT GEOTECNNIC,I X. Appendix D Page D-7 Standard Grading Specifications not be allowed to roll off at the edge of the slope. It may be helpful to elevate slightly the outer edge of the slope. Slough resulting from the placement of individual lifts should not be -- allowed to drift down over previous lifts. At intervals not exceeding four feet in vertical slope height or the capability of available equipment,whichever is less,fill slopes should be thoroughly dozer trackrolled. For pad areas above fill slopes, positive drainage should be established away from the top-of-slope. This may be accomplished using a berm and pad gradient of at least 2 percent. Section 8 - Trench Backfill Utility and/or other excavation of trench backfill should, unless otherwise recommended, be compacted by mechanical means. Unless otherwise recommended,the degree of compaction should be a minimum of 90 percent of the laboratory maximum density. Within slab areas,but outside the influence of foundations,trenches up to one foot wide and two feet deep may be backfilled with sand and consolidated by jetting, flooding or by mechanical means. If on-site materials are utilized,they should be wheel-rolled,tamped or otherwise compacted to a firm condition. For minor interior trenches,density testing may be deleted or spot testing may be elected if deemed necessary, based on review of backfill operations during construction. If utility contractors indicate that it is undesirable to use compaction equipment in close proximity to a buried conduit, the contractor may elect the utilization of light weight mechanical compaction equipment and/or shading of the conduit with clean,granular material,which should be thoroughly jetted in-place above the conduit, prior to initiating mechanical compaction procedures. Other methods of utility trench compaction may also be appropriate, upon review of the geotechnical consultant at the time of construction. In cases where clean granular materials are proposed for use in lieu of native materials or where flooding or jetting is proposed, the procedures should be considered subject to review by the geotechnical consultant. Clean granular backfill and/or bedding are not recommended in slope areas. Section 9 - Drainage Where deemed appropriate by the geotechnical consultant, canyon subdrain systems should be installed in accordance. Typical subdrains for compacted fill buttresses, slope stabilization or sidehill masses, should be installed in accordance with the specifications. Roof,pad and slope drainage should be directed away from slopes and areas of structures to suitable disposal areas via non-erodible devices (i.e., gutters, downspouts, and concrete swales). ,CTE SER%'ER PRGSECTS I G)45)G RPT GF(ITECI iN'ICA4UOC Appendix D Page D-8 Standard Grading Specifications For drainage in extensively landscaped areas near structures,(i.e.,within four feet)a minimum of 5 percent gradient away from the structure should be maintained. Pad drainage of at least 2 percent should be maintained over the remainder of the site. Drainage patterns established at the time of fine grading should be maintained throughout the life of the project. Property owners should be made aware that altering drainage patterns could be detrimental to slope stability and foundation performance. Section 10 - Slope Maintenance 10.1 - Landscape Plants To enhance surficial slope stability,slope planting should be accomplished at the completion of grading. Slope planting should consist of deep-rooting vegetation requiring little watering. Plants native to the southern California area and plants relative to native plants are generally desirable. Plants native to other semi-arid and and areas may also be appropriate. A Landscape Architect should be the best party to consult regarding actual types of plants and planting configuration. 10.2 - Irrigation Irrigation pipes should be anchored to slope faces, not placed in trenches excavated into slope faces. Slope irrigation should be minimized. If automatic timing devices are utilized on irrigation systems, provisions should be made for interrupting normal irrigation during periods of rainfall. 10.3 -Repair As a precautionary measure,plastic sheeting should be readily available,or kept on hand,to protect all slope areas from saturation by periods of heavy or prolonged rainfall. This measure is strongly recommended, beginning with the period prior to landscape planting. If slope failures occur,the geotechnical consultant should be contacted for a field review of site conditions and development of recommendations for evaluation and repair. If slope failures occur as a result of exposure to period of heavy rainfall,the failure areas and currently unaffected areas should be covered with plastic sheeting to protect against additional saturation. "CTE SERVER!PROIECTS• 7457G� GLOTM%[C. .DOC