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HomeMy WebLinkAboutCT 06-25; Robertson Ranch PA 21; Robertson Ranch PA 21; 2008-11-24REPORT OF ROUGH GRADING PLANNING AREA 21 OF ROBERTSON RANCH, EAST VILLAGE CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA FOR BROOKFIELD SAN DIEGO BUILDERS, INC. 12865 POINTE DEL MAR, SUITE 200 SAN DIEGO, CALIFORNIA 92014 oy W.O. 5353-B1-SC NOVEMBER 24, 2008 0 CO ULJ CO 00 co oui o Geotechnical * Geologic • Coastal • Environmental 5741 Palmer Way • Carlsbad, California 92010 • (760)438-3155 • FAX (760) 931-0915 November 24, 2008 W.O. 5353-B1-SC Brookfield San Diego Builders, Inc. 12865 Pointe Del Mar, Suite 200 Del Mar, California 92014 Attention: Ms. Teri McHugh Subject: Report of Rough Grading, Planning Area 21 of Robertson Ranch, East Village Carlsbad, San Diego County, California Dear Ms. McHugh: This report presents a summary of the geotechnical testing and observation services provided by GeoSoils, Inc. (GSI) during the rough earthwork construction phase of development associated with the development of Planning Area 21 (PA-21) of Robertson Ranch East Village, in the City of Carlsbad, San Diego County, California. Earthwork was performed in conjunction with the grading of the larger Robertson Ranch East Village. Earthwork commenced in April 2007, and was generally completed in July 2008. PURPOSE OF EARTHWORK The purpose of this phase of grading was to prepare building pads and associated street areas for the construction of approximately 84 multi-family residential structures, one recreation area, and associated surface and subsurface improvements. Cut-and-fill grading techniques were utilized to attain the desired graded configurations. Existing colluvium (topsoil), alluvium, and weathered formational material were removed to suitable earth material (as defined in the approved report for this portion of the project tract), and either exported from the site or recompacted as fill. Rough grading is generally completed throughout PA-21. The approximate limits of grading under the purview of this report are shown on the Geotechnical Maps (Plates 1 through 4), which use the 20-scale grading plan for this project, prepared by O'Day Consultants (O'Day, 2007), as a base. ENGINEERING GEOLOGY Subsurface geologic conditions exposed during the process of rough grading were observed by a representative of GSI. Prior to grading, earth materials onsite consisted of surflcial deposits of colluvium (topsoil), and alluvium, underlain by terrace deposits (considered bedrock), orformational sediments belonging to the Santiago Formation (also considered bedrock). The subsurface conditions exposed were generally as anticipated per our approved geotechnical report (GSI, 2007b). Perimeter grading, along the south side of PA-21, as indicated on Plates 1 through 4, was performed prior to this phase of earthwork with geotechnical observation and testing services provided by GSI (2006e and 2007a). Grading of PA-21 was completed at the same time as grading of the larger Robertson Ranch East Village project, to the west, north, and east, of PA-21. GEOLOGIC STRUCTURE As observed onsite, the bedding structure observed within terrace deposits is generally thickly bedded and sub-horizontal. Bedding structure was not well developed within the thickly-bedded Santiago Formation, but generally dips on the order of 5 to 10 degrees to the northwest, based on mapping in the vicinity and a review of GSI (2004 and 2007b). GROUNDWATER Naturally occurring perched groundwater was encountered during rough grading at depths generally less than 10 feet below the pre-construction grades, or approximately 40 to 45 feet below as-graded pads, near the former bedrock/alluvium contact. Where feasible, subdrains were constructed, as discussed herein. Regional groundwater should not significantly affect the performance of the fill, provided that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions may develop in the future due to rainfall, excess irrigation, homeowner altered drainage, or damaged utilities, and should be anticipated along cut/fill contacts or areas within compacted fill with contrasting permeabilities. Should manifestations of perched conditions (i.e., seepage, develop in the future), this office should assess the conditions and provide rnitigative recommendations, as necessary. A discussion of subdrainage constructed during grading is presented in a later section of this report. EARTHWORK CONSTRUCTION Earthwork operations have been completed in general accordance with the City grading ordinance, approved recommendations provided by GSI (see the Appendix), and the guidelines provided in the field by this office. Observations during grading included removals, excavation, and fill placement, along with general grading procedures of compacted fills by the contractor. Table 1 presents a summary of compaction test results. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 Me:e:\wp9\5300\5353b1 ror.pa21 Page 2 GeoSoils, Inc. Rough Grading Preparation of Existing Ground 1. Deleterious material, such as concentrated organic matter and miscellaneous debris, were stripped from the surface and disposed of beyond the limits of grading for the subject area, prior to placing any fill. 2. Loose surficial materials (i.e., existing topsoils, colluvium, alluvium, and unsuitable formational soils), were removed to expose suitable bearing soils, as defined in the approved report for the site. 3. Lots containing cut/fill transitions, lots containing non-uniform native soil conditions, and lots exposing terrace deposits or bedrock near finish grade, were undercut per the approved report. In general, undercuts were completed to depths no less than 3 feet across a given lot, and/or to minimum depths no less than about one-third the maximum fill depth across any given lot (i.e., to create a minimum to maximum fill thickness ratio of 1:3). Approximate as-built fill depths are indicated in Table 2. 4. Subsequent to completing removals, areas to receive compacted fill were scarified, moisture conditioned, and then compacted to attain a minimum relative compaction of 90 percent (ASTM D 1557). These areas were then brought to grade with fill compacted to a minimum 90 percent relative compaction, based on field observations. 5. All processing of original ground in areas to receive fill, shown on Plates 1 through 4, was observed by a representative of GSI. Plates 1 through 4 utilize the 20-scale grading plans prepared by O'Day (2007), as a base map. Fill Placement Fill consisted of onsite and import materials which were placed in thin lifts, approximately 4 to 8 inches in thickness, brought to at least optimum moisture content, and compacted to attain a minimum 90 percent relative compaction per ASTM 1557. Approximate as-built fill depths are shown in Table 2. The presence of scattered rock fragments, on the order of 12 inches in size, more or less, cannot be precluded from occurring within any of the fills onsite. Compaction test results for fills are presented in the attached Table 1. Fill containing rock fragments up to approximately 24 inches in size, more or less, were placed at depth, below about 5 to 10 feet, per the approved report (GSI, 2007b), in the general vicinity of Lots 13 through 52. Where fills contained a significant amount of rock, precluding testing in accordance with ASTM D1556, D 2922, and D 3017, a "method only" (Nichols, 1976) technique was employed in conjunction with areas where testing, using the procedures described above, could be performed. In these areas, the material was spread Brookfield San Diego Builders, Inc. W.O. 5353-81-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1 ror.pa21 Page 3 GeoSoils, Inc. out in lifts on the order of 1 to 2 feet thick, mixed with sandy materials, flooded with water, and rolled with fully loaded, heavy rock trucks. Rolling was completed until further movement of the material was not observed. Once an areas was compacted, test pits were completed to evaluate moisture content and the presence of void spaces. Where adverse conditions were observed, these areas were re-excavated and replaced with a suitable soil rock mixture until satisfactory. Oversize material was placed in general accordance with recommendations presented in the approved report (GSI, 2007b), and placed no closer than approximately 5 to 10 feet from finish grade. Nonetheless, shallow excavation may encounter oversize materials. Slopes Graded Slopes Graded slopes constructed under the purview of this report are generally on the order of 10 to 20 feet in height, or less, and should typically perform satisfactorily with respect to gross and surficial stability under normal conditions of care, maintenance, and rainfall (semi-arid). Fill slopes, constructed under the purview of this report, were provided with a basal bench, or keyway, excavated into suitable earth material in general accordance with the approved GSI recommendations (see References [Appendix A]). Cut slopes were not constructed during this phase of grading. Temporary Slopes Any proposed/future temporary construction slopes may be constructed at a gradient of 1:1 (horizontahvertical [h:v]), or flatter, in compacted fill (provided adverse conditions are not present, as evaluated by GSI prior to workers entering trenches), provided seepage or groundwater is not present. Utility trenches may be excavated in accordance with guidelines presented in Title 8 of the California Code of Regulations for Excavation, Trenches, and Earthwork, with respect to "Type B" soil (compacted fill), again provided seepage or groundwater is not present. Construction materials and/or stockpiled soil should not be stored within 'H' from the top of any temporary slope, where 'H' is the height of the slope, in feet. Temporary/permanent provisions should be made to direct any potential runoff away from the top of temporary slopes. Natural Slopes Natural slopes are not present within PA-21. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1 ,ror.pa21 Page 4 <GeoSoils, Inc. Subdrainaqe A canyon subdrain system, constructed in general accordance with the approved report (GSI, 2007b) and GSI field recommendations, was placed within a pre-existing canyon area in Planning Area 18 (north of PA-21) and continues into PA-21, in the general vicinity of Building Pads 25,29,30,32,33,37, and 38 (see Plate 1). The subdrain system ultimately is connected to the storm drain system near Cannon Road. Field Testing 1. Field density tests were performed using the sand-cone method (ASTM D1556) and nuclear (densometer) method (ASTM D 2922 and D 3017). Tests taken for the Robertson Ranch project were taken in consecutive numerical order. However, only tests within the subject site, under the purview of this report, are presented in Table 1 at the end of the text, therefore test sequencing may be periodically non-consecutive, but consistent with the testing on the tract as a whole. The approximate locations of field density tests are shown on the Geotechnical Maps (Plates 1 through 4), which utilize the 20-scale grading plans, prepared by O'Day (2007), as a base map. 2. Field density tests were taken at periodic intervals and random locations to check the compactive effort provided by the contractor. Rock corrections were applied during testing of fill with significant rock fragments, as appropriate. Based on the operations observed, test results presented herein are generally considered representative of the fills observed under the purview of this report. 3. Visual classification of the soils in the field, as well as random laboratory testing, was the basis for determining which maximum dry density value to use for a given density test. 4. Testing and observations were performed on a full time basis. LABORATORY TESTING Moisture-Density Relations The laboratory maximum dry density and optimum moisture content for each major soil type occurring within PA-21 was determined in general accordance with test method ASTM D 1557. Non-consecutive lettering indicated in the following table is a result of soil types being part of the soil type sequence for the larger Robertson Ranch development. The following table presents the test results: Brookfield San Diego Builders, Inc. W.O. 5353 81-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1 ror.pa21 Page 5 GeoSoils, Inc. SOIL TYPE A - Brown, Silty SAND B - Dark Brown. Clayey SAND C - Gray Brown, Clayey SAND D - Brown, Silty SAND E Dark Brown. Silty SAND F- Gray Brown, Gravelly SAND H - Gray Brown, Gravelly SAND J - Gray, Clayey SAND L - Olive Brown, Silty CLAY M -Yellow Brown, Silty SAND (import) Q - Yellowish Gray, Silty SAND (import) S -Yellowish Gray. SAND w/CLAY (import) X - Dark Red Brown. Silty SAND (import) Y - Brown, Clayey SAND AA - Brown, Silty SAND BB - Grav. Siltv CLAY MAXIMUM DRY DENSJTY focfl 127.0 114.0 120,5 128.0 126.0 134.0 134.0 121.0 111.0 123.0 127.0 124.0 131.5 119.0 123.0 113.5 OPTIMUM MOISTURE CONTENT (%) 10.0 13.0 13.0 10.0 11.0 8.0 9.0 12.5 18.5 12.5 11.0 11.0 9.0 14.5 11.5 13.5 Expansion Index Expansion Index (E.I.) tests were performed for the representative foundation soil types exposed near finish grade in general accordance with ASTM D 4829 in groups of three to four pads, or if there was a significant change in expansive character. An E.I. test summary is presented in Table 2, at the end of this report. Atterberg Limits Laboratory testing was performed to evaluate the Atterberg Limits (liquid limit, plastic limit, and plasticity index) in general accordance with ASTM D 4318 for representative soils exposed near finish grade that exhibited an E.I. greater than 20 or had high fines (-200 sieve) content. The results of Atterberg Limit testing are presented in Table 2. Corrosion Analysis Representative samples of the site materials has been analyzed for soluble sulfates, soil pH, and saturated resistivity by Schiff Associates, Inc. (Corrosion Consultants). Based upon the laboratory testing, the majority of site soils are considered to be negligible (sulfate class SO, American Concrete Institute [ACI] 318-08) with respect to water soluble sulfate exposure to concrete. This classification is in accordance with Tables 4.2.1 and 4.3.1 of ACI 318-08 (California Building Code [CBC], California Building Standards Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch. East Village File:e:\wp9\5300\5353b1 .ror.pa21 W.O. 5353-B1-SC November 24, 2008 Page 6 fceoSoils, Inc. Commission [CBSC], 2007). Soils are relatively neutral with respecttosoil acidity/alkalinity (pH = 7.4 [Romanoff, 1957]), and are very corrosive to exposed ferrous metals in a saturated state (saturated resistivity <1,000 ohm-cm). The chloride ion content in soil for the lots was also noted to be below action levels per Caltrans (1999) (i.e., <300 ppm). It is our understanding that standard concrete cover over reinforcing steel is usually appropriate for these conditions; however, a corrosion engineer should be consulted to provide specific recommendations regarding foundations and buried piping, etc. A summary of the results of the soil sulfate evaluation are presented in Table 2. FOUNDATION RECOMMENDATIONS In the event that information concerning the proposed development plan is not correct, or any changes in the design, location or loading conditions of the proposed structure are made, the conclusions and recommendations contained in this report shall not be considered valid unless the changes are reviewed and conclusions of this report are modified or approved in writing by this office. The conclusions and recommendations presented in GSI (2007b) are generally considered valid and applicable unless specifically superceded in the text of this report. Recommendations for conventional and post-tensioned foundation systems are provided in the following sections. RECOMMENDATIONS - CONVENTIONAL FOUNDATIONS General The foundation design and construction recommendations are based on laboratory testing and engineering analysis of onsite earth materials by GSI. The foundation systems may be used to support the proposed structures, provided they are founded in competent bearing material (i.e., founded entirely in compacted fill or rippable bedrock), with no exposed transitions. Conventional foundations may be used for very low to low expansive soil subgrades, where the soils plasticity index (P.I.) is 15, or less. For low to medium expansive soil conditions where the P.I. is greater than 15, conventional foundations may be used, provided that they are designed in accordance with Chapter 18 (Section 1805A.8) of the CBC (CBSC, 2007). When soils have an E.I. >21 and P.I. >15, this implies that the Code may require the use of more onerous foundations (i.e., post-tension, mat, etc.). The information and recommendations presented in this section are minimums and not meant to supercede design (s) by the project structural engineer. Upon request, GSI could provide additional information/consultation regarding soil parameters, as related to foundation design. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch. East Village November 24, 2008 File:e:\wp9\5300\5353b1 ror.pa21 Page 7 &eo£oils, Inc. As-Built Conditions As-built soil conditions to be minimally considered in foundation design and construction are presented in Table 2 of this report. Foundation Design Based on the as-graded conditions, the minimum geotechnical recommendations for foundation design and construction are presented below. Bearing Value 1. The foundation systems should be designed and constructed in accordance with guidelines presented in the latest edition of the CBC (CBSC, 2007). 2. An allowable bearing value of 2,000 pounds per square foot (psf) may be used for the design of continuous footings at least 12 inches wide and 12 inches deep, and isolated column footings at least 24 inches square and 24 inches deep, connected by a grade beam back to the main foundation in at least one direction. The bearing surface is assumed to be approved compacted fill, placed as part of the overall site grading. This value may be increased by 20 percent for each additional 12 inches in depth to a maximum of 3,000 psf. No increase in bearing value is recommended for increased footing width. The allowable bearing pressure may be increased by one-third under the effects of temporary loading, such as seismic or wind loads. Lateral Pressure 1. For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a concrete to compacted fill soil contact when multiplied by the dead load. 2. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pounds per cubic foot (pcf) with a maximum lateral earth pressure of 2,500 psf. 3. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third and the previously noted maximum lateral earth pressure applied. Differential Settlement AH foundation systems (conventional and post tension) should be designed to minimally accommodate a differential settlement of at least 1 inch in a 40-foot span. This includes long-term static as well as dynamic effects. Brookfield San Diego Builders, Inc. W.0.5353-B1 -SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 8 &eoSoils, Inc. Seismic Shaking Parameters The table below summaries the site-specific design criteria obtained per the 2007 CBC. We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the U.S.G.S. The short spectral response uses a period of 0.2 seconds. CBC SEISMIC DESIGN PARAMETERS FOR SITE CLASS "D" SOILS PARAMETER Site Class Spectral Response - (0.2 sec), Ss Spectral Response - (1 sec) S, Site Coefficient, F, Site Coefficient, Fy Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec) S^ Maximum Considered Earthquake Spectral Response Acceleration (1 sec), SM1 5% Damped Design Spectral Response Acceleration (0.2 sec), SDS 5% Damped Design Spectral Response Acceleration (1 sec), Sn, VALUE D 1.15g 0.44g 1.04 1.56 1.20g 0.68g 0.79g 0.46g CBC REFERENCE Table 1613.5.2 Figure 161 3.5(3) Figure 161 3.5(4) Table 1613.5.3(1) Table 161 3.5.3(2) Section 1613.5.3 (Eqn 16-37) Section 1613.5.3 (Eqn 16-38) Section 1613.5.4 (Eqn 16-39) Section 1613.5.4 (Egn 16-40) A probabilistic peak horizontal ground acceleration (PHSA) of 0.28 g was evaluated for this site (GSI, 2007b). This value was chosen as it corresponds to a 10 percent probability of exceedence in 50 years (or a 475-year return period). Conformance to the criteria above for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur in the event of a large earthquake. The primary goal of seismic design is to protect life, not to eliminate all damage, since such design may be economically prohibitive. Construction The following foundation construction recommendations are presented as a minimum criteria from a soils engineering standpoint. Recommendations by the project's design-structural engineer or architect, which may exceed the soils engineer's recommendations, should take precedence over the following minimum requirements. Minimal conventional foundation recommendations are presented in the following Table A, followed by an explanation of the "Foundation Category," and other minimal criteria. Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village File: e:\wp9\5300\5353b1 .ror.pa21 W.O. 5353-81-SC November 24, 2008 Page 9 Inc. TABLE A - CONVENTIONAL PERIMETER FOOTINGS; AND SLABS, ROBERTSON RANCH EAST VILLAGE FOUNDATION CATEGORY 1 II III MIN, FOOTING SIZE 12"Widex 12" Deep 12" Wide x 18" Deep 12-Widex 24' Deep Mia INTERIOR SLAB " THICKNESS 4' Thick 4" Thick 5" Thick MIN. REINFORCING STEEt, 1-No.4Bar Top & Bottom 2 No. 4 Bars Top & Bottom 2-No. 5 Bars Top & Bottom MIN. INTERIOR SLAB, REINFORCEMENT No. 3 Bars® 18* o.c. Both Directions No. 3 Bare® 18" o.c. Both Directions No. 3 Bars® 18" o.c. Both Directions MIN.:• UNDER-SLAB - TREATMENT 2" Sand Over 10-MB vapor retardar Over 2" Sand Base 2" Sand Over 10/1 SAW vapor retarder Over 2* Sand Base (15-mil (or medium expansive soils only) 2" Sand Over 15-Mil vapor retarder Over 3" Sand Base (highly expansive soils only) MIN. GARAGE SLAB REINFORCEMENT 6"X6" (10/10) welded wire fabric (WWF) ffxef (6/6) WWF, or No. 3 Bars © 18" o.c Both Directions for Low Same as Interior Slab EXTERIOR FLATWORK REINFORCING None 6-X6" 10x10 WWF 6"x6" (6/6) WWF Category Criteria Category I: Max, Fill Thickness is less than 201 and E.I. is less than, or equal to, 50 (P.I. <15) and Differential RII Thickness is less than 10' (see Note 1). Category II: Max. RII Thickness is less than 30* or E.I. is less than, or equal to, 90 or Differential FiS Thickness is between 10 and 20* (see Note 1). Presoaking required. Category III: Max. Fill Thickness exceeds 30*. or E.I. exceeds 90 but is less than 130, or Differential RII Thickness exceeds 20* (see Note 1). Presoaking required. Notes: 1. Conventional foundations shall also be designed per Section 1 SOSA.8, Chapter 18 of the CBC (CBSC, 2007) where the P.I. is 15, or greater. 2. Post-tension-foundations are required where maximum fill exceeds 30", or the ratio of the maximum fill thickness to the minimum till thickness exceeds 3:1, or where the E.I. exceeds 90, or in areas underlain with alluvial soil len in place. Differential settlements discussed in the body of the report should be incorporated into foundation design by the structural engineer/slab designer. 3. Fooling depth measured from lowest adjacent compacted/suitable subgrade. 4. The allowable soil bearing pressure is 2,000 psf. 5. Concrete for slabs and footings shall have a minimum compressive strength of 2,500 psl at 28 days. The maximum slump shall be 5 inches. The water/cement ratio of concrete shall not be more than 0.5 for soils with an El. >9O. 6. The vapor retardar is not required under garage slabs. However, consideration should be given to future uses of the slab area, such as room conversion and/or storage of moisture-sensitive materials and disclosure. All vapor retarders should be placed in accordance with ASTM E 1643, and the CBC (CBSC, 2007). 7. Isolated footings shall be connected to foundations per soils engineer's recommendations (see report). 8. Sand used for base under slabs shall be a 'dean* granular material, and have SE >30. "Pea" gravel may be substituted for the basal sand layer in order to improve water transmission mitigation. 9. Additional exterior flatwork recommendations are presented in the text of this report 10. All slabs should be provided with weakened plane joints to control cracking. Joint spacing should be in accordance with correct industry standards and reviewed by the project structural engineer. 11. Pre-wetting is recommended for all soil conditions as follows: very low to low expansive (at least optimum moisture content to a depth of 18 inches, medium expansive (at least 2-3% over optimum to a depth of 18 inches), highly to very highly expansive (at least 4-5% over optimum to a depth of 24 inches). POST-TENS1ONED SLAB DESIGN Post-tensioned slab foundation systems may be used to support the proposed building. Based on the as-built soil conditions, post-tensioned slabs may be designed for low to highly expansive soil conditions, as indicated below. General The information and recommendations presented in this section are not meant to supercede design by a registered structural engineer or civil engineer familiar with post-tensioned slab design or corrosion engineering consultant. Upon request, GSI could provide additional data/consultation regarding soil parameters as related to post-tensioned slab design during grading. The post-tensioned slabs should be designed in accordance with the Post-Tensioning Institute (PTI) Method (3rd Edition). Alternatives to the PTI method may be used if equivalent systems can be proposed which Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village Fi!e:e:\wp9\5300\5353b1 .ror.pa21 W.O. 5353-81-SC November 24, 2008 Page 10 GeoSoils, Inc. accommodate the angular distortions, expansion potential and settlement noted for this site. Preliminary Foundation Design Based on the as-built graded conditions within the subject lots, the following table in general accordance with the CBC (CBSC, 2007) presents foundation design parameters for post-tensioned slab foundations relative to a specific range of soil expansion potential. Settlement criteria is provided in a previous section of this report, and GSI (2007b). TABLE B - POST-TENSION FOUNDATIONS EXPANSION POTENTIAL em center lift em edge lift ym center lift ym edge lift Bearing Value (1> Lateral Pressure Subgrade Modulus (k) Foundation Category per GSI (2007b) Minimum Perimeter Footing Embedment (2) VERY LOW TO LOW _ (EJ. = 0-50) 9.0 feet 5.2 feet 0.30 inches 0.7 inch 1 ,000 psf 250 psf 1 00 pci/inch Category I PT 12 inches MEDIUM (E.I. = 51-90) 8.7 feet 4.5 feet 0.49 inches 1.3 inch 1,000 psf 250 psf 85 pci/inch Category II PT 1 8 inches HIGH (E.I. =91-120) 8.5 feet 4.0 feet 0.66 inches 1 .7 inches 1,000 psf 250 psf 70 pci/inch Category III PT 24 inches m Internal bearing values within the perimeter of the post-tension slab may be increased to 2,000 psf for a minimum embedment of 1 2 inches, then by 20 percent for each additional foot of embedment to a maximum of 3,000 psf. ^ As measured below the lowest adjacent compacted subgrade surface. Note: The use of open bottomed raised planters adjacentto foundations will require more onerous design parameters. Subgrade Preparation The subgrade material should be compacted to a minimum 90 percent of the maximum laboratory dry density. Prior to placement of concrete, the subgrade soils should be moisture conditioned in accordance with the following discussion. Should the property sit unimproved for a period of 12 months, or longer, remedial treatment of the building pads, including, but not limited to scarification, and removal/recompaction, cannot be precluded and should be anticipated. An updated geotechnical document in accordance with City requirements shall be provided if the site is allowed to sit fallow. Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village Rle:e:\wp9\5300\5353b1,ror.pa21 W.O. 5353-B1-SC November 24, 2008 Page 11 , Inc. Perimeter Footings and Pre-Wetting From a soil expansion/shrinkage standpoint, a fairly common contributing factor to distress of structures using post-tensioned slabs is a significant fluctuation in the moisture content of soils underlying the perimeter of the slab, compared to the center, causing a "dishing" or "arching" of the slabs. To mitigate this possible phenomenon, a combination of soil pre-wetting and construction of a perimeter cut-off wall (minimum 12 inches deep) grade beam/typical footing should be employed. Deepened footings/edges around the slab perimeter must be used to minimize non-uniform surface moisture migration (from an outside source) beneath the slab. Embedment depths are presented in Table B. The bottom of the deepened footing/edge should be designed to resist tension, using cable or reinforcement per the structural engineer. Other applicable recommendations presented under conventional foundation recommendations in the referenced report should be adhered to during the design and construction phase of the project. Floor slab subgrade should be treated in accordance with criteria presented in Table A, Note 11. Pre-wetting of the slab subgrade soil prior to placement of steel and concrete will likely be recommended and necessary, in order to achieve optimum moisture conditions. Soil moisture contents should be evaluated at least 72 hours prior to pouring concrete. If pre-wetting of the slab subgrade is completed prior to footing excavation, the pad area may require period wetting in order to keep to soil from drying out. The level of moisture needed will be dependant on the length of elapsed time between the date of the pad(s) completion and the day of foundation/final improvements. MITIGATION OF WATER VAPOR TRANSMISSION The following methodologies for vapor transmission mitigation are provided below with respect to the Robertson Ranch, East Village Project, are also presented in Table A. The following minimum guidelines have been developed in accordance with the expansive character of the building pad subgrade within about 7 feet of finish grade. Very Low to Low Expansive Soils For floor slabs bearing on very low to low expansive soil subgrades (E.I. of 50, or less), the floor slab should be underlain with 2 inches of sand, over a 10-mil polyvinyl membrane (vapor retarder), over a 2-inch sand base. Sand used should have a minimum sand equivalent of 30. The minimum concrete compressive strength should be 2,500 psi. (upgraded from the prior recommendations [GSI, 2004]), and constructed in accordance with ACI 302.1 R-04. The vapor retarder should comply with the ASTM E 1745 - Class A or B criteria, and be installed in accordance with ACI 302.1 R-04 (ASTM 1643), and the CBC (CBSC, 2007). Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1 .ror.pa21 Page 12 GeoSoils, Inc. Medium to Highly Expansive Soils For floor slabs bearing on medium expansive soil subgrades (E.I. between 51 and 90), the slab should be underlain with 2 inches of sand (SE >30), over a 15-mil vapor retarder, over a minimum 2-inch sand (SE >30) base. The minimum concrete compressive strength should be at least 2,500 psi. The vapor retarder should comply with the ASTM E 1745 - Class A or B criteria, and be installed in accordance with ACI 302.1 R-04 (ASTM 1643). A 2-inch layer of "pea" gravel may be substituted for the sand layer used beneath the vapor retarder if it is desired to further mitigate water/water vapor transmission. A 3-inch layer of "pea" gravel or clean coarse sand is required for highly expansive soils, if present. Other Considerations Regardless of the soils expansion potential, an additional improvement to moisture protection would be to extend the vapor retarder/membrane beneath all foundation elements and grade beams. In addition, because it has been shown that the lateral migration of water from foundation edges may contribute significantly to excess moisture transmission, the vapor retarder/membrane could extend slightly above soils grade around the slab/foundation perimeter and the exposed foundation face could be painted with a latex sealer prior to color coat. Recognizing that these measures go beyond the current standard of care, we recommend that the developer evaluate the construction issues and costs associated with the additional measures above and determine the feasibility of implementing them. While these methods are considered to be overall improvements to the existing recommendations for this project (GSI, 2004 and 2007b), they will only minimize the transmission of water vapor through the slab, and may not completely mitigate it. Floor slab sealants may also be used for a particular flooring product, if necessary. The use of concrete additives that reduce the overall permeability (water reducers) of the concrete may also be considered. Generally, slab moisture emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab (Kanare, 2005), while typical floor covering manufacturers recommend about 3 lbs/24 hours as an upper limit. Accordingly, floor coverings and improvements that can tolerate these anticipated rates should be considered by the developer/owner. SETBACKS All settlement-sensitive improvements should maintain a minimum horizontal setback of H/3 (H-slope height) from the base of the footing to the descending slope face of no less than 7 feet, nor need not be greater than 40 feet. This distance is measured from the improvement or footing face at the bearing elevation. Footings adjacent to unlined drainage swales should be deepened to a minimum of 6 inches below the invert of the Brookfield San Diego Builders, Inc. W.O. 5353 B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 13 £eo$oils, Inc. adjacent unlined swale. Footings for structures adjacent to retaining walls should be deepened so as to extend below a 1:1 projection from the heel of the wall. Alternatively, walls may be designed to accommodate structural loads from buildings or appurtenances, as described in the retaining wall section of this report. SOLUBLE SULFATES/RESISTIVITY Based on our testing and experience in the vicinity, the majority of site soils are anticipated to have a negligible sulfate exposure to concrete per Table 4.2.1 and 4.3.1 of ACI318-08, and the 2007 CBC (see Table 2). Site soils are also anticipated to be very corrosive to buried metal. This level of corrosion was evaluated by saturated resistivity test(s). As such, the amount of soil will influence the variation in soil corrosivity to exposed/buried rnetal improvements. Consultation with a corrosion engineer is recommended, by the designer, and/or developer. WALL DESIGN PARAMETERS Conventional Retaining Walls Retaining walls should be designed in accordance with the CBC (CBSC, 2007). The design parameters provided below assume that either non-expansive soils (Class 2 permeable filter material or Class 3 aggregate base) or native materials (up to and including an E.I. of 50) are used to backfill any retaining walls. The type of backfill (i.e., select or native), should be specified by the wall designer, and clearly shown on the plans. Building walls, below grade, should be water-proofed. The foundation system for the proposed retaining walls should be designed in accordance with the recommendations presented in this and preceding sections of this report regarding conventional foundation design, as appropriate. The bottom of footings should be embedded a minimum of 18 inches below adjacent grade (excluding landscape layer, 6 inches) and should be 24 inches in width. There should be no increase in bearing for footing width. Recommendations for specialty walls (i.e., crib, earthstone, geogrid, etc.) can be provided upon request, and would be based on site specific conditions. Based on the as-built condition of the pad, and the current site development plan (O'Day, 2007, revised 2008), several cut/fill transitions will likely occur within the influence of planned walls. Recommendations for the treatment of transitions are presented in a later section of this report. Restrained Walls Any retaining walls that will be restrained prior to placing and compacting backfill material or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid pressure (EFP) of 100 pcf (native soil) or 60 pcf (select), plus any applicable surcharge Brookfield San Diego Builders, Inc. W.O. 5353-B1 -SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\S353b1.ror.pa21 Page 14 OeoSoils, Inc. loading, per Table 1610.1 of the CBC (CBSC, 2007) for USCS soil classification SM-SC. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for walls less than 3 feet in height may be superceded by City and/or County standard design. Active earth pressure may be used for retaining wall design, provided the top of the wall is not restrained from minor deflections. An equivalent fluid pressure approach may be used to compute the horizontal pressure against the wall. Appropriate fluid unit weights are given below for specific slope gradients of the retained material. These do not include other superimposed loading conditions due to traffic, structures, seismic events or adverse geologic conditions. When wall configurations are finalized, the appropriate loading conditions for superimposed loads can be provided upon request. Traffic load surcharges should be applied within a distance 'H' in feet behind the wall, where 'H' is the height of the wall. Earthquake loads need only be applied for walls that are 6 feet or more of retained earth and/or will impede access to, and from, residences, or the project site. SURFACE SLOPE OF RETAINED MATERIAL (HORIZONTAL:VERTICAL> EQUIVALENT FLUID WEIGHT P.C.F. (SELECT PRE-APPROVED BACKFILL**) EQUIVALENT FLUID WEIGHT P.C.F. (NATIVE BACKFILL***) i*Lave 2to1 35 50 45 60 * Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without a slope for a distance of 2H behind the wall. ** SE >.30 and <10 percent passing No. 200 sieve. *** E.I. <50, SE >20, and PI <15. Values minimally conform to Table 1610.1 of the CBC (CBSC. 2007) Retaining Wall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in goofabric and outlets. A backdrain system is considered necessary for retaining walls that are 2 feet or greater in height. Backdrains should consist of a 4-inch diameter perforated PVC or ABS pipe encased in either Class 2 permeable filter material or 1/2-inch to 3/4-inch gravel wrapped in approved filter fabric (Mirafi 140 or equivalent). For low expansive backfill, the filter material should extend a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For native backfill that has up to medium expansion potential, continuous Class 2 permeable drain materials, or Va-inch to 3A-inch gravel wrapped in approved filter fabric (Mirafi 140, or equivalent) should be used behind Brookfield San Diego Builders, Inc. W.O. 5353-B1 -SC PA 21 Robertson Ranch, East Village November 24, 2008 Filc:e:\wp9\5300\5353b1.ror.pa21 Page 15 j Inc. the wall as backfill within the active zone, defined as the area above a 1:1 projection up from the base of the wall stem. This material should be continuous (i.e., full height) behind the wall. The surface of the backfill should be sealed by pavement or the top 18 inches compacted to 90 percent relative compaction with native soil. For limited access and confined areas, (panel) drainage behind the wall may be constructed. Materials with an E.I. potential of greater than 65 should not be used as backfill for retaining walls, regardless of the criteria for backfill summarized in the preceding table. Any wall drainage plan should be reviewed by this office for approval prior to construction. Wall backfill should be made by relatively light equipment. The contractor should avoid stockpiling earth or any building material within 2H of newly completed/backfilled walls, where H is the height of the wall, in feet. Weeping of the walls in lieu of a backdrain is not recommended for walls greater than 2 feet in height. For walls 2 feet, or less, in height, weepholes should be no greater than 6 feet on center in the bottom coarse of block and above the landscape zone. Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than ±100 feet apart, with a minimum of two outlets, one on each end. The use of only weep holes in walls higher than 2 feet should not be considered. The surface of the backfill should be sealed by pavement or the top 18 inches compacted with native soil (E.I. <50). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of a waterstop should be considered for all concrete and masonry joints. Proper surface drainage should also be provided in order to reduce the potential for surface water penetration. Wall/Retaining Wall Footing Transitions Site walls are anticipated to be founded on footings designed in accordance with the recommendations in this report. Should wall footings transition from cut to fill, the civil designer may specify either: a) A minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. b) Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 1/360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be placed no greater than 20 feet on-center, in accordance with the structural engineer's/wall designer's recommendations, regardless of whether or not transition conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout. c) Embed the footings entirely into native formational material (i.e., deepened footings). Brookfield San Diego Builders, Inc. W.O. 5353-B1 SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 16 &eo$oils, Inc. If transitions from cut to fill transect the wall footing alignment at an angle of less than 45 degrees (plan view), then the designer should follow recommendation "a" (above) and until such transition is between 45 and 90 degrees to the wall alignment. The presence of transitions beneath planned improvements with result in an elevated potential for distress to the particular improvement, unless the recommendations presented above are implemented. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Due to the potential for slope creep (see the "Development Criteria" section for a discussion) for slopes higher than about 10 feet, some settlement and tilting of the walls/fence with the corresponding distresses, should be expected. To mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be constructed on deepened foundations without any consideration for creep forces, where the expansion index of the materials comprising the outer 15 feet of the slope is less than 50, or a combination of grade beam and caisson foundations, for expansion indices greater than 50, comprising the slope, with creep forces taken into account Recommendations for grade beam and caisson foundations can be provided upon request. Deepened foundations should minimally provide for a lateral distance of 7 feet from the outside bottom edge of the footing to the face of slope and provide enough lateral resistance for creep forces. DRIVEWAY. FLATWORK. AND OTHER IMPROVEMENTS The effects of expansive soils are cumulative, and typically occur over the lifetime of any improvements. On relatively level areas, when the soils are allowed to dry, the dessication and swelling process tends to cause heaving and distress to flatwork and other improvements. The resulting potential for distress to improvements may be reduced, but not totally eliminated. To reduce the likelihood of distress, the following recommendations are presented for all exterior flatwork: 1. The subgrade area for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction. If very low to low expansive soils are present, only optimum moisture content, or greater, is required and specific presoaking is not warranted. For medium, or higher expansive soils, the subgrade should be presoaked to 2 to 3 percentage points above (or 125 percent of) the soils' optimum moisture content, to a depth of 12 inches below subgrade elevation. The moisture content of the subgrade should be evaluated by the geotechnical consultant within 72 hours prior to pouring concrete. 2. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 17 GeoSoils, Inc. prior to pouring concrete. If very low to low expansive soils are present, the rock or gravel or sand is not required. The layer or subgrade should be wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. Cut/fill transitions should be mitigated beneath any settlement sensitive improvement. The adverse effects of transitions may be mitigated by undercutting the cut portion of the transition at least 2 feet below the grade, and replacing with compacted fill. 3. Exterior slabs should be a minimum of 4 inches thick. When driveways are placed over rock, gravel or clean sand, driveway slabs and approaches should additionally have a thickened edge which isolates the bedding material from any adjacent landscape area, to help impede infiltration of landscape water under the slab. 4. The use of transverse and longitudinal control joints are recommended to help control slab cracking due to concrete shrinkage or expansion. Two ways to mitigate such cracking are: a) add a sufficient amount of reinforcing steel, increasing tensile strength of the slab; and, b) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. In order to reduce the potential for unsightly cracks, exterior slabs may be reinforced as indicated in Table A. The exterior slabs should be scored or saw cut, to a minimum depth of T/4, where "T" is the thickness of the slabs in inches. Saw cuts should be provided often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion/shrinkage joint filler material. 5. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. Concrete compression strength should be a minimum of 2,500 psi. 6. Driveways, sidewalks, and patio slabs adjacent to a structure should be separated from the structure with expansion/shrinkage joint filler material. In areas directly adjacent to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should be additionally sealed with flexible mastic. 7. Planters and walls should not be tied to the structure. 8. Overhang structures should be supported on the slabs, or structurally designed with continuous footings tied in at least two directions. If very low expansion soils are present, footings need only be tied in one direction. Brookfield San Diego Builders, Inc. W.O. 5353-B1 -SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1 .ror.pa21 Page 18 GeoSoils, Inc. 9. Any masonry landscape walls that are to be constructed throughout the property should be grouted and articulated in segments no more than 20 feet long. These segments should be keyed or doweled together. 10. Utilities should be enclosed within a closed utilidor (vault) or designed with flexible connections to accommodate differential settlement and expansive soil conditions. 11. Positive site drainage should be maintained at all times. Rnish grade on the pads should provide for an adequate fall to the street, per the design civil engineer. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are not periodically maintained by the homeowner or homeowners association. 12. Air conditioning (A/C) units should be supported by slabs that are incorporated into the building foundation, or constructed on an isolated rigid slab with flexible couplings for plumbing and electrical lines. A/C waste water lines should be drained to a suitable outlet. 13. Shrinkage cracks could become excessive if proper finishing and curing practices are not followed. Finishing and curing practices should be performed per the Portland Cement Association Guidelines. Mix design should incorporate rate of curing for climate and time of year, sulfate content of soils, corrosion potential of soils, and fertilizers used on site. If spray on typical curing is employed, apply as soon as possible after finishing. Use Hunt's curing compound, or equivalent. PRELIMINARY PAVEMENT DESIGN Preliminary pavement section design was performed in general accordance with the California Department of Transportation (Caltrans) Highway Design Manual of Instructions (2006), traffic index data provided by the project civil engineer, and the minimum sections per the City. Pavement sections are based on the aforementioned criteria, the City of Carlsbad (1993) design criteria, and the resistance R-value data estimated for the area. TRAFFIC AREA Parking Lot Stalls/Cul De Sac/ Low Traffic Private Streets Private Streets T.I. 4.5 5.0 SUBGRADE R-VALUE 9 9 A.C. THICKNESS (Inches) 4.0 4.0 AGGREGATE BASE THICKNESS™ (Inches) 5.0 7.0 (1) Denotes Class 2 Aggregate Base "FTsJS, SE >^25). Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village File:e;\wp9\5300\5353b1.ror.pa21 W.O. 5353-B1-SC November 24, 2008 Page 19 GeoSoils, Inc. Final pavement sections shall be based on site specific R-value testing upon completion of underground improvements. All pavement construction should be performed in accordance with the currently approved, and applicable specifications, and the standard of practice. Best management construction practices should be followed at all times, especially during inclement weather. Due to the relatively low R-value(s) of the soil samples obtained from finished subgrade, GSI recommends that drainage of the subgrade and provisions for irrigation and other water should not be allowed to penetrate street subgrades. GSI will assist the civil designer to reduce this potential. DEVELOPMENT CRITERIA Slope Deformation General Compacted fill slopes, designed using customary factors of safety for gross or surficial stability, and constructed in general accordance with the design specifications, should be expected to undergo some differential vertical heave, or settlement, in combination with differential lateral movement in the out-of-slope direction, after grading. This post-construction movement occurs in two forms: slope creep; and, lateral fill extension (LFE). Slope Creep Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (i.e., separations and/or cracking), placed near the top-of-slope, generally within a horizontal distance of approximately 15 feet, measured from the outer, deepest (bottom outside) edge of the improvement, to the face of slope. The actual width of the zone affected is generally dependant upon: 1) the height of the slope; 2) the amount of irrigation/rainfall the slope receives; and, 3) the type of materials comprising the slope. This movement generally results in rotation and differential settlement of improvements located within the creep zone. Suitable mitigative measures to reduce the potential for distress due to lateral deformation typically include: setback of improvements from the slope faces (per the 2007 CBC); positive structural separations (i.e., joints) between improvements; and, stiffening and deepening of foundations. Per Section 1805.3.1 of the 2007 CBC, a horizontal setback (measured from the slope face to the outside bottom edge of the building footing) of H/3 is provided for structures, where H is the height of the fill slope in feet, and H/3 (to be minimally 7 feet), need not be greater than 40 feet. Alternatively, in consideration of the discussion presented above, site conditions and Section 1805.3.1 of the 2007 CBC, H/3 Brookfield San Diego Builders, Inc. W.O 5353-B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 20 OeoSoils, Inc. generally need not be greater than 20 feet for the development. As an alternative to a deepened footing, where the adjacent slope is greater than 45 feet in height and the building/footing is within 20 feet from the slope face, a differential settlement of 0.5 inch (additional) may be applied to the design of that portion of the structure(s). Any settlement-sensitive improvements (i.e., walls ,spas, flatwork, etc.) should minimally consider the above. Lateral Fill Extension (LFE) LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Based on the generally very low expansive character of onsite soils, the potential component of slope deformation due to LFE is considered minor, but may not be totally precluded. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by generally placing the fill throughout the slope region, wet of the fill's optimum moisture content, as was done on this project. Summary It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the CBC [CBSC, 2007]); positive structural separations (i.e., joints) between improvements; stiffening; and, deepening of foundations. All of these measures are recommended for design of structures and improvements and minimizing the placement of "dry" fills. Slope Maintenance and Planting Water has been shown to weaken the inherent strength of all earth materials. Slope stability is significantly reduced by overly wet conditions. Positive surface drainage, away from slopes, should be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements and cause perched groundwater conditions. Graded slopes constructed utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopes would tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting, or other fibrous covers, may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc. to develop. A rodent control program to prevent burrowing should be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended. Over-steepening of slopes should be avoided during building construction activities and Brookfield San Diego Builders, Inc. W.0.5353-81-SC PA 21 Robertson Ranch, East Village November 24. 2008 Rle:e.\wp9\530G\53S3b1.ror.pa21 Page 21 OeoSoils, Inc. landscaping. All landscaping plans should be reviewed by a qualified civil engineer with respect to site drainage and compatibility with adjoining properly uses. Drainage Adequate pad surface drainage is a very important factor in reducing the likelihood of adverse performance of foundations, hardscape, and slopes. Surface drainage should be sufficientto prevent ponding of water anywhere on a lot, and especially near structures and tops of slopes. Pad surface drainage should be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care should be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within pads and common areas should be provided and maintained at all times. Drainage should not flow uncontrolled down any descending slope. Water should be directed away from foundations and not allowed to pond and/or seep into the ground. In general, the area within 3 feet around a structure should slope away from the structure. We recommend that unpaved lawn and landscape areas have a minimum gradient of 1 percent sloping away from structures, and whenever possible, should be above adjacent paved areas. Consideration should be given to avoiding construction of raised planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage should be directed toward the street or other approved area(s). Although not a geotechnical requirement, roof gutters, down spouts, or other appropriate means may be utilized to control roof drainage. Down spouts, or drainage devices, should outlet a minimum of 3 feet from structures or into an alternate, approved area, such as a drainage system swale. Areas of seepage may develop due to irrigation or heavy rainfall, and should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage develop, recommendations for minimizing this effect could be provided upon request. Geotechnical recommendations for drainage practices are included herein. The civil consultant and landscape planner(s) should provide additional recommendations in accordance with local practices. Erosion Control Cut and fill slopes will be subject to surficial erosion during and after grading. Onsite earth materials have a moderate to high erosion potential. Consideration should be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We recommend that any open-bottom, raised box planters adjacent to proposed structures be restricted for a minimum distance of 10 feet. As an alternative, closed-bottom type raised planters could be utilized. An outlet placed in the bottom of the planter could be Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch, East Village November 24. 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 22 GeoSoils, Inc. installed to direct drainage away from structures or any exterior concrete flatwork. If raised box planters are constructed adjacent to structures, the sides and bottom of the planter should be provided with a moisture retarder to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint, leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided the recommendations contained in this report are incorporated into final design and construction, and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Perched groundwater conditions, along zones of contrasting permeabilities, may not be precluded from occurring in the future due to site irrigation, poor drainage conditions, or damaged utilities, and should be anticipated. Should perched groundwater conditions develop, this office could assess the affected area(s) and provide the appropriate recommendations to mitigate the observed groundwater conditions. Groundwater conditions may change with the introduction of irrigation, rainfall, or other factors. Tile Flooring Tile flooring can crack, reflecting cracks in the concrete slab below the tile, although small cracks in a conventional slab may not be significant. The tile installer should consider installation methods that reduce possible cracking of the tile such as slipsheets, a vinyl crack isolation membrane, or other approved method by the Tile Council of America/Ceramic Tile Institute. Site Improvements If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the site, recommendations concerning the geological or geotechnical aspects of design and construction of said improvements could be provided upon request. Pools and/or spas should not be constructed without specific design and construction recommendations from GSI, and this construction recommendation should be provided to the homeowners association or other interested/affected parties. This office should be notified in advance of any fill placement, grading of the site, or trench backfilling after rough grading has been completed. This includes any grading, utility trench and retaining wall backfills, flatwork, etc. Brookfield San Diego Builders, Inc. W.O. 5353-B1 -SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9V5300\5353b1 .ror.pa21 Page 23 GeoSoils, Inc. Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the street and parking areas and utility trench and retaining wall backfills. Rough grading is generally completed throughout PA-21. Preliminary Pool/Spa Design Recommendations The following minimal preliminary recommendations are provided for consideration in pool/spa design and planning. The following recommendations should be provided to any contractors and/or subcontractors, etc., that may perform such work. 1. The pool system should be designed and constructed in accordance with guidelines presented in the latest adopted edition of the CBC (CBSC, 2007). The pool shell should be embedded entirely into properly compacted fill. Pools proposed in the vicinity of Lots 20 through 24 may require overexcavation for the pool shell due to the presence of hard rock. Rock fragments should be anticipated within any excavation, especially in the vicinity of Lots 37 through 43,64 through 72, 100 through 103, 113 through 116, 141 through 145, 152 through 159, and 190 through 194. Overexcavation depths should be reviewed on a lot by lot basis, as plans are developed. 2. The equivalent fluid pressure against a cantilever wall free to yield at the top, may minimally be assumed as 62 pcf. 3. The equivalent fluid pressure against a non-yielding wall or a wall restrained from movement at the top, may be minimally assumed as 100 pcf, per the CBC (CBSC, 2007) for these soil conditions. 4. The preceding unit weights do no include superimposed loading from expansive soil pressure, earthquakes, traffic or adjacent building/wall loads. These loads could be provided upon request. 5. Passive earth pressure may be computed as an equivalent fluid having a density of 250 pcf, to a maximum earth pressure of 2,500 psf. 6. An allowable coefficient of friction between soil and concrete of 0.35 may be used with the dead load forces. 7. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third. Brookfield San Diego Builders, Inc. W.O. 5353-81-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror pa21 Page 24 GeoSoils, Inc. 8. The geotechnical consultant should review and approve all aspects of pool/spa and flatwork design prior to construction. Recommendations for pool flatwork are presented in a following section. A design civil engineer should review all aspects of such design, including drainage and setback conditions, per the CBC (CBSC, 2007), 9. All aspects of construction should be reviewed and approved by the geotechnical consultant, including during excavation, priorto the placement of any additional fill, prior to the placement of any reinforcement or pouring of any concrete. 10. Where pools are planned near structures, appropriate surcharge loads need to be incorporated into design and construction by the pool designer. 11. All pool walls should be designed as "free standing" and be capable of supporting the water in the pool without soil support per Section 1805.3.3, Chapter 18 of the CBC (CBSC, 2007). 12. The pool structure should be set back from any adjacent descending slope in accordance with the CBC (CBSC, 2007). 13. The soil beneath the pool/spa bottom should be uniformly moist with the same stiffness throughout. If a fill/cut transition occurs beneath the pool bottom, the cut portion should be overexcavated to a minimum depth of 24 inches, and replaced with compacted fill. The fill should be placed at a minimum of 90 percent relative compaction, at over-optimum moisture conditions. The potential for grading and/or re-grading of the pool bottom, and attendant potential for shoring and/or slot excavation, needs to be considered during all aspects of pool planning, design, and construction. If pool subgrade conditions are wet, or saturated, provisions for drying back overexcavated soils, or importing/mixing with drier soils may be necessary. In order to minimize the effects of expansive soils, soils placed above the undercut should be low expansive (E.I. <50). 14. Hydrostatic pressure relief valves should be incorporated into the pool and spa designs. A pool under-drain system should also be considered, with an appropriate outlet for discharge, depending on pool location. 15. All fittings and pipe joints, particularly fittings in the side of the pool or spa, should be properly sealed to prevent water from leaking into the adjacent soils materials. 16. An elastic expansion/shrinkage joint (waterproof sealant) should be installed to prevent water from seeping into the soil at all deck joints. 17. Reinforced grade beams should be placed around skimmer inlets to provide support and mitigate cracking around the skimmer face. Brookfield San Diego Builders, Inc. W.O. 5353-81 -SC PA 21 Robertson Ranch, East Village November 24. 2008 Fi!e:e:\wp9\5300\5353b1.ror.pa21 Page 25 GeoSoils, Inc. 18. Pool decking/flatwork should be pre-wet/pre-soaked per the Foundation Section of this report. 19. Regardless of the methods employed, once the pool/spa is filled with water, should it be emptied, there exists some potential that if emptied, significant distress may occur. Accordingly, once filled, the pool/spa should not be emptied unless evaluated by the geotechnical consultant. Footing Trench Excavation All footing excavations should be observed by a representative of this firm subsequent to trenching and prior to concrete form and reinforcement placement The purpose of the observations is to verify that the excavations are made into the recommended bearing material and to the minimum widths and depths recommended for construction. If loose or compressible materials are exposed within the footing excavation, a deeper footing or removal and recompaction of the subgrade materials would be recommended at that time. Footing trench spoil and any excess soils generated from utility trench excavations should be compacted to a minimum relative compaction of 90 percent, if not removed from the site. Trenching Considering the nature of the onsite soils, it should be anticipated that caving or sloughing could be a factor in subsurface excavations and trenching. Shoring or excavating the Irench walls at the angle of repose (typically 25 to 45 degrees) may be necessary and should be anticipated. All excavations should be observed by one of our representatives and minimally conform to Cal-OSHA and local safety codes. Utility Trench Backfill 1. All interior utility trench backfill should be brought to at least 2 percent above optimum moisture content and then compacted to obtain a minimum relative compaction of 90 percent of the laboratory standard. As an alternative for shallow (12-inch to 18-inch) under-slab trenches, sand having a sand equivalent value of 30 or greater may be utilized and jetted or flooded into place. Observation, probing and selective testing should be provided to evaluate the desired results. 2. Exterior trenches adjacent to, and within areas extending below a 1:1 plane projected from the outside bottom edge of the footing, and all trenches beneath hardscape features and in slopes, should be compacted to at least 90 percent of the laboratory standard. Sand backfill, unless excavated from the trench, should not be used in these backfill areas. Selective compaction testing and observations, along with probing, should be accomplished to verify the desired results. Brookfield San Diego Builders, Inc. WO. 5353-81-SC PA ?1 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353bI.ror pa21 Page 26 GeoSoils, Inc. 3. All trench excavations should conform to Cal-OSHA and local safely codes. 4. Utilities crossing grade beams, perimeter beams, or footings should either pass below the footing or grade beam utilizing a hardened collar or foam spacer, or pass through the footing or grade beam in accordance with the recommendations of the structural engineer. SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND TESTING We recommend that observation and/or testing be performed by GSI at each of the following construction stages: • During grading/recertification. • After excavation of building footings, retaining wall footings, and free standing walls footings, prior to the placement of reinforcing steel or concrete. Prior to pouring any slabs or flatwork, after presoaking/presaturation of building pads and other flatwork subgrade, before the placement of concrete, reinforcing steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders (i.e., visqueen, etc.), as necessary. • During retaining wall subdrain installation, prior to backfill placement. • During placement of backfill for area drain, interior plumbing, utility line trenches, and retaining wall backfill, as necessary. • During slope construction/repair. • When any unusual soil conditions are encountered during any construction operations, subsequent to the issuance of this report. When any developer or homeowner improvements, such as flatwork, spas, pools, walls, etc., are constructed. A report of geotechnical observation and testing and/or field testing reports, should be provided at the conclusion of each of the above stages as necessary, in order to provide concise and clear documentation of site work, and/or to comply with code requirements. • GSI should review project sates documents to homeowners/homeowners associations for geotechnical aspects, including irrigation practices, the conditions Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 21 Robertson Ranch, East Village November 24, 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 27 GeoSoils, Inc. outlined above, etc., prior to any sales. At that stage, GSI will provide homeowners maintenance guidelines which should be incorporated into such documents. OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer, structural engineer, post-tension designer, architect, landscape architect, wall designer, etc., should review the recommendations provided herein, incorporate those recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. This report presents minimum design criteria for the design of slabs, foundations and other elements possibly applicable to the project. These criteria should not be considered as substitutes for actual designs by the structural engineer/designer. The structural engineer/designer should analyze actual soil-structure interaction and consider, as needed, bearing, expansive soil influence, and strength, stiffness and deflections in the various slab, foundation, and other elements in order to develop appropriate, design-specific details. As conditions dictate, it is possible that other influences will also have to be considered. The structural engineer/designer should consider all applicable codes and authoritative sources where needed. If analyses by the structural engineer/designer result in less critical details than are provided herein as minimums, the minimums presented herein should be adopted. It is considered likely that some, more restrictive details will be required. If the structural engineer/designer has any questions or requires further assistance, they should not hesitate to call or otherwise transmit their requests to GSI. In orderto mitigate potential distress, the foundation and/or improvement's designer should confirm to GSI and the governing agency, in writing, that the proposed foundations and/or improvements can tolerate the amount of differential settlement and/or expansion characteristics and design criteria specified herein. HOMEOWNERS/HOMEOWNERS ASSOCIATIONS It is recommended that the developer should notify, and/or make available the findings, conclusions and recommendations presented in this report to any homeowners or homeowners association, in order to minimize any misunderstandings regarding the design and performance of earth structures, and the design and performance of existing and/or future or proposed improvements. PLAN REVIEW Any additional project plans generated for this project should be reviewed by this office, prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Brookfield San Diego Builders, Inc. W.0.5353-B1 -SC PA 21 Robertson Ranch, East Village November 24. 2008 File:e:\wp9\5300\5353b1.ror.pa21 Page 28 GeoSoils, Inc. LIMITATIONS The materials encountered on the project site and utilized for our analysis are believed representative of the area; however, soil and bedrock materials vary in character between excavations and natural outcrops or conditions exposed during mass grading. Site conditions may vary due to seasonal changes or other factors. Inasmuch as our study is based upon our review and engineering analyses and laboratory data, the conclusions and recommendations are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty, either express or implied, is given. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. All samples will be disposed of after 30 days, unless specifically requested by the Client, in writing. Brookfield San Diego Builders, Inc. WO. 5353-B1 -SC PA 21 Robertson Ranch, East Village November 24. 2008 File:e:\wp9\5300\5353b1 ror.pa21 Page 29 GeoSoils, Inc. The opportunity to be of service is sincerely appreciated, questions, please do not hesitate to call our office. Respectfully submitted. GeoSoils, Inc. ' "* ^"" r If you should have any Robert G. Cris Engineering Reviewed by: John P. Franklin Engineering Geolog RGC/ATG/JPF/jh Attachments: Andrew T. Guatelli Geotechnical Engineei Distribution: Table 1 - Field Density Test Results Table 2 - Pad Characteristics Appendix - References Plates 1 through 4 - Geotechnical Maps (4) Addressee (2) O'Day Consultants, Attention: Mr. Keith Hansen Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, Fast Village File:e:\wp9\!i300\5353b 1 ,ror.pa21 W.O. 5353-B1-SC November 24, 2008 Page 30 <Geo$oils, Inc. Table 1 FIELD DENSITY TEST RESULTS TEST NO. 1' 2' 3' 4' 5' 6' 7 8' 9' 10' 11' 12' 13' 14' 15' 16' 17' 18' 19' 20' 2V 22' 23' 24' 25' 26' 27' 28' 29' 30' 31' 32' 33' 34' 35' 36' 371 38' 39' 40' 41' 42' 43' 44' DATE 4/23/07 4/23/07 4/23/07 4/23/07 4/24/07 4/24/07 4/24/07 4/24/07 4/25/07 4/25/07 4/25/07 4/25/07 4/25/07 4/26/07 4/26/07 4/26/07 4/26/07 4/27/07 4/30/07 4/30/07 4/30/07 4/30/07 5/1/07 5/1/07 5/1/07 5/1/07 5/1/07 5/2/07 5/2/07 5/2/07 5/2/07 5/2/07 5/3/07 5/3/07 5/3/07 5/3/07 5/4/07 5/4/07 5/4/07 5/4/07 5/4/07 5/4/07 5/7/07 5/7/07 TEST LOCATION Pad El. 73.9 Pad El. 75.5 Pad El. 77.1 Pad El. 77.1 Pad El. 73.9 Pad El. 75.5 Pad El. 77.1 Pad El. 77.1 Pad El. 82.5 Pad El. 84.0 Pad El. 85.4 Pad El. 85.4 Pad El. 85.4 Pad El. 82.5 Pad El. 84.0 Pad El. 85.4 Pad El. 85.4 Pad El. 85.4 Pad El. 86.8 Pad El. 86.8 Pad El. 78.4 A Street Pad El. 86.8 Pad El. 86.8 Pad El. 85.4 Pad El. 84.0 Pad El. 84.0 Pad El. 85.4 Pad El. 85.4 Pad El. 84.0 Pad El. 82.5 Pad El. 84.0 Pad El. 78.4 Pad El. 85.4 Pad El. 86.8 Pad El. 77.1 Pad El. 85.4 Pad El. 86.8 Pad El. 86.8 Pad El. 84.0 Pad El. 86.8 Pad El. 82.5 Glen Ave 19+00 Glen Avs 18+50 TRACT NO.- PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 EUEV OR DEPTH (ft) 54.0 56.0 57.0 59.0 61.0 63.0 65.0 71.0 48.0 50.0 53.0 55.0 58.0 43.0 45.0 47.0 48.0 56.0 58.0 60.0 62.0 65.0 66.0 66.0 67.0 68.0 69.0 69.0 70.0 70.0 71.0 72.0 67.0 68.0 69.0 70.0 71.0 71.0 72.0 73.0 74.0 74.0 60.0 63.0 MOISTURE CONTENT (%) 13.2 12.5 12.4 13.6 13.3 12.9 14.0 13.0 13.6 11.9 13.1 14.0 13.5 13.9 12.9 12.8 13.4 12.8 12.4 13.6 13.1 14.9 12.6 13.3 12.5 13.6 14.0 11.9 13.5 12.6 13.1 12.5 10.0 10.5 10.7 10.9 13.5 13.9 12.9 12.8 13.4 13.6 13.1 13.5 DRY DENSITY (PCO 127.6 126.2 127.9 128.2 126.0 123.9 124.1 125.7 125.1 123.1 124.4 122.9 122.8 125.2 124.3 124.8 124.6 125.9 127.9 128.2 123.1 122.9 123.8 128.1 126.2 128.0 122.9 125.6 122.8 125.9 123.1 123.2 123.0 122.2 125.0 1242 122.8 125.2 124.3 124.8 124.6 128.0 127.1 126.3 REL COMPw 95.2 94.2 95.4 95.6 94.0 92.4 92.5 93.9 93.3 91.8 92.8 91.7 91.6 93.4 92.7 93.1 93.0 93.9 95.4 95.6 91.9 91.7 92.4 95.6 94.1 95.5 91.7 93.7 91.6 94.0 91.9 91.8 91.8 91.2 93.3 92.6 91.6 93.4 92.7 93.1 93.0 95.5 94.8 94.2 TESCT METHOD ND ND ND ND ND SC ND ND ND ND SC ND ND ND ND ND ND SC SC ND ND ND ND ND SC SC ND ND ND ND ND SC ND ND ND ND SC SC ND ND ND ND ND SC SOIL TYPE F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F F Brookfield San Oiego Builders, Inc. PA 21 Robertson Ranch, East Village File: C:\excelttables\5300\5353b1 .ror.paZI , Inc. W.O. 5353-B1-SC November 2008 Page 1 Table 1 FIELD DENSITY TEST RESULTS TEST NO. 47 181* 181 A* 181B 182* 182A* 182B 189 190 191 192 222 223 224 225 226 244 245 248 249 251 252 253 254 255 256 260 262 263 264 265 266 267 268 269 446* 446A 447* 447A 448 449 451 452 454 DATE 5/7/07 5/1/07 5/3/07 5/3/07 5/1/07 5/3/07 5/3/07 5/3/07 5/3/07 5/3/07 5/3/07 5/7/07 5/7/07 5/7/07 5/7/07 5/7/07 5/8/07 5/8/07 5/8/07 5/8/07 5/8/07 5/8/07 5/8/07 5/8/07 5/8/07 5/8/07 5/9/07 5/9/07 5/9/07 5/9/07 5/9/07 5/9/07 5/9/07 5/9/07 5/9/07 6/5/07 6/5/07 6/5/07 6/5/07 6/5/07 6/5/07 6/5/07 6/5/07 6/6/07 TEST LOCATION Glen Ave 17+60 Pad El. 78.4 Pad El. 78.4 Pad El. 78.4 Summit Trail Court Summit Trail Court Summit Trail Court Pad El. 73.9 Pad El. 75.5 Pad El. 88.9 Pad El. 77.5 Pad El. 82.5 Pad El. 82.5 Pad El. 84.0 Pad El. 84.0 Pad El. 80.7 Pad El. 82.5 Pad El. 88.9 Pad El. 78.4 Glen Ave 17+00 Pad El. 86.8 Pad El. 86.8 Pad El. 88.9 Pad El. 88.9 Pad El. 87.8 Pad El. 87.8 A Street Pad El. 84.0 Pad El. 84.0 A Street Pad El. 87.8 A Street Pad El. 86.8 Pad El. 88.9 Pad El. 88.9 Cannon Rd 143 +50 Cannon Rd 143+50 Cannon Rd 143+30 Cannon Rd 143+30 Cannon Rd 142+00 Cannon Rd 141+60 Cannon Rd 143+00 Cannon Rd 141+00 Cannon Rd 142+75 TRACT NO. PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 , ELEV OR DEPTH (ft) 55.0 66.0 66.0 65.0 68.0 68.0 67.5 70.0 70.0 72.0 72.0 74.0 74.0 76.0 76.0 76.0 74.0 74.0 72.0 76.0 76.0 76.0 78.0 78.0 78.0 80.0 81.0 81.0 83.0 83.0 85.0 85.0 84.0 85.0 86.0 64.0 64.0 64.0 64.0 62.0 62.0 66.0 660 68.0 MOISTURE CONTEKT (%) 12.6 13.2 15.8 19.3 14.1 14.9 18.7 13.0 13.7 11.2 11.0 13.1 13.0 13.8 13.0 14.1 13.1 14.2 12.8 13.1 12.8 12.7 13.6 13.0 14.2 13.2 13.6 13.1 13.4 13.0 13.7 13.2 14.3 14.2 13.7 9.9 11.5 10.2 11.9 11.5 11 1 12.0 11.3 12.0 DRY DENSITY (PCD 125.9 95.9 97.9 100.8 96.8 96.5 101.2 108.7 109.3 114.6 114.2 108.7 108.5 109.3 103.3 104.3 110.2 102.7 110.1 110.7 109.8 110.2 102.6 102.9 102.8 103.6 109.4 109.8 109.4 110.1 102.9 103.5 102.7 102.8 102.7 113.0 117.7 112.7 117.1 117.6 118.0 116.9 117.8 116.9 REL COMP (%) 94.0 86.4 88.2 90.8 87.2 86.9 91.2 90.2 90.7 91.0 90.6 90.3 90.0 90.7 90.6 91.4 91.1 90.0 91.0 91.5 90.7 91.1 90.0 90.3 90.1 90.9 90.8 91.1 90.8 91.4 90.3 90.8 90.1 90.3 90.1 89.6 93.4 89.4 92.9 93.3 93.6 92.7 93.4 92.7 TESCT METHOD ND ND ND ND ND ND ND ND ND ND ND ND SC ND ND ND ND SC ND ND ND ND ND ND SC ND SC ND ND ND SC ND ND ND ND ND ND ND ND ND SC ND SC ND SOIL TYPE F L L L L L L C C E E C C C B B J B J J J J B B B B C C C C B B B B B E E E £ E E E E E Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village File: C:\excel\tables\5300\5353b1 .ror.pa21 SeoSoils, Inc. W.O. 5353-B1-SC November 2008 Page 2 TABLE 2 - BUILDING PAD CHARACTERISTICS, PA-21 BLDG. No. 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 E.I. (ASTM D 4829) 25 25 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 21 69 69 69 69 69 69 69 69 21 21 21 21 <20 <20 <20 EXPANSION POTENTIAL*1' Low Low Low Low Low Low Low Low Low I ow Low Low Low Low Low Low Low Low Medium Medium Medium Medium Medium Medium Medium Medium Low Low Low Low Very Low Very Low Very Low SULFATE EXPOSURE12* Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible PLASTICITY INDEX (PI)131 16-20 16-20 s15 .<15 <;15 s15 *15 =s15 *15 <15 ^15 s15 s15 16-20 16-20 s15 16-20 16-20 25-29 25-29 25-29 25-29 25-29 25-29 25-29 25-29 s15 s15 s15 s15 i15 s15 s15 APPROX. DEPTH OF FILL (RANGE IN FT.) 12-19 7-13 25-30 17-30 20-34 30-35 35-38 32-36 36-39 36-39 27-37 36-40 30-36 22-27 15-24 20-30 11-16 12-14 4-8 4-10 3-4 3-4 3-4 3-4 3-5 3-5 3-9 4-8 3-5 3-4 3-4 3-4 3-5 FOUNDATION TYPE(4> I I III III III III III III III III 111 III III II II III I I II II II II II II II II I I I I I I I Brookfield San Diego Builders, Inc. Rle:e:\wp12\5300\5353b1.ror.pa21 Table 2 Page 2 &eoSoils, Inc. TABLE 2 - BUILDING PAD CHARACTERISTICS, PA-21 BLDG. No. 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 Rec.* Lot E.I. (ASTM 0 4829) <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 I" <20 <20 <20 <20 <20 <20 <20 <20 EXPANSION POTENTIAL0' Very Low Low Low Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low Very Low SULFATE EXPOSURE'2' Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible PLASTICITY INDEX (PIL(3) i15 16-20 16-20 16-20 «15 s15 s15 i15 i15 i15 s15 s15 s15 i15 &-\5 s15 *15 i15 APPROX. DEPTH OF FILL (RANGE IN FT.) 3-5 8-15 8-18 16-17 17-21 20-25 20-26 26-27 24-31 29-32 25-31 30-32 32-33 30-33 25-33 33-34 33-34 3-8 FOUNDATION TYPE(4> I I I I II II II II III HI III III III III III III III N/A <" Per ASTM 4829. (2) Per ACI 318-08, Tables 4.2.1 and 4.3.1 (CBC, 2007) <3) The higher value in the range provided, should be used for design purposes. (4> Per GSI (2007b). * Recreation Area - Foundation design to be lot specific based on proposed use; will be provided upon review of site development. N/A - Not Applicable Brookfield San Diego Builders, Inc. File:e:\wp12\5300\5353b1 ,ror.pa21 Table 2 Pages GeoSoils, Inc. Table 1 FIELD DENSITY TEST RESULTS TEST NO. 455 458 802 833 841 842 843 844 845 846 847 853 857* 857A 858 859 860 861 862 863 864 874 875 876 877 881 882 883 884 885 886 887 908 909 910 911 924 925 926 927 928 929 930 931 DATE 6/6/07 6/6/07 7/12/07 7/19/07 7/23/07 7/23/07 7/23/07 7/23/07 7/24/07 7/24/07 7/24/07 7/24/07 7/25/07 7/25/07 7/25/07 7/25/07 7/25/07 7/25/07 7/25/07 7/25/07 7/25/07 7/26/07 7/26/07 7/26/07 7/26/07 7/27/07 7/27/07 7/27/07 7/31/07 7/31/07 7/31/07 7/31/07 7/31/07 7/31/07 7/31/07 7/31/07 8/1/07 8/1/07 8/1/07 8/1/07 8/1/07 8/2/07 8/2/07 8/2/07 TEST LOCATION Cannon Rd 141+50 Cannon Rd 142+00 Glen Ave 18 +50 Glen Ave, Choker S. Side Lot 95 Cannon Rd Pad El. 76.5 Cannon Rd Cannon Rd Pad El. 75.5 Pad El. 76.5 Cannon Rd Glen Ave, Choker 14+40 Pad El. 80.7 Pad El. 80.7 Pad El. 80.7 Pad El. 80.7 Glen Ave, S. Side Choker 15+00 Glen Ave, S. Side Choker 16+00 Glen Ave, S. Side Choker 17+00 Glen Ave, S. Side Choker 18+00 Glen Ave, S. Side Choker 17+50 Pad El. 79.9 Pad El. 79.9 Pad El. 87.8 Pad El. 88.9 Pad El. 87.8 Pad El. 88.9 Pad Ei. 88.9 Pad El. 77.5 Pad El. 77.5 Pad El. 77.5 Pad El. 77.5 Pad El. 75.5 Pad El. 76.5 Pad El. 77.1 Pad El. 77.1 Pad El.77.5 Pad El.76.5 Pad El.77.5 Pad El.76.5 Pad El.77.5 Pad El.77.5 Pad El.76.5 Pad El.77.5 TRACT NO* PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 ELEV OR DEPTH (ft) 68.0 72.0 82.0 73.0 66.0 66.0 68.0 68.0 70.0 70.0 71.0 78.0 74.0 74.0 76.0 78.0 80.0 80,0 82.0 83.0 84.0 73.0 77.0 83.0 83.0 84.0 85.0 86.0 72.0 74.0 76.0 76.0 74.0 74.0 76.0 76.0 68.0 69.0 70.0 71.0 72.0 70.0 71.0 72.0 MOISTURE CONTENT (%) 11.5 11.9 12.9 12.2 14.0 15.3 14.6 13.9 14.3 13.9 14.2 13.1 6.7 14.2 19.9 20.6 12.3 11.8 11.1 12.0 12.6 13.1 13.7 14.0 12.9 13.7 13.0 12.7 14.6 14.1 15.2 15.0 14.6 13.9 13.7 14.8 9.5 10.3 10.6 9.2 9.0 9.2 9.0 9.7 ^RY DENSJTY (pef) 117.4 117.0 109.4 118.3 108.6 110.1 109.3 109.1 112.8 109.5 111.2 114.3 105.6 109.5 101.1 100.3 118.2 118.8 119.7 118.5 117.9 112.0 111.4 110.9 112.4 110.0 110.8 111.3 108.4 109.5 109.1 110.6 111.8 110.8 110.9 112.7 124.5 123.7 123.3 124.9 125.3 124.9 125.2 124.5 REL COMP W 93.1 92.8 90.4 93.8 90.1 91.4 90.7 90.5 93.6 90.9 92.3 92.9 87.6 90.9 91.1 90.4 93.8 94.2 95.0 94.0 93.5 92.6 92.1 91.7 92.9 90.9 91.6 92.0 90.0 j 90.9 90.5 91.8 91.6 90.8 90.9 92.4 94.6 94.0 93.7 94.9 95.5 94.9 95.2 94.6 TESCT METHOD NO ND SC ND ND SC ND ND ND ND ND SC ND ND SC ND ND ND ND ND SC ND ND SC ND ND ND ND ND ND ND SC SC SC SC SC ND ND SC ND ND ND ND SC SOIL TYPE E E J E C C C C C C C M C C L L E E E E E J J J J J J J C C C C Q Q Q Q X X X X X X X X Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village File; C:\excol\tablos\5300VS353b1 .ror pa21 GeoSoils, Inc. W.O. 5353-B1-SC November 2008 PageS Table 1 FIELD DENSITY TEST RESULTS TEST NO. 932 933 942 943 944 945 946 947 948 949* 949A 950* 950A 951* 951 A 952* 952A 953 954 955 956 959 960 961 994-FG 995 996 997 998 999 1000 1001 1002 1003 1004 1008 1009* 1009A 1010 1014'-S 1015-S 1016'-S 1017--S 1018'-S DATE 8/2/07 8/2/07 8/3/07 8/3/07 8/3/07 8/3/07 8/6/07 8/6/07 8/6/07 8/6/07 8/6/07 8/6/07 8/6/07 8/7/07 8/7/07 8/7/07 8/7/07 8/7/07 8/7/07 8/7/07 8/7/07 8/8/07 8/8/07 8/8/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/16/07 8/17/07 8/17/07 8/17/07 8/17/07 8/17/07 8/17/07 8/17/07 8/17/07 8/17/07 TEST LOCATION Pad El.76.5 Pad El.77.5 Pad El. 78.8 Pad El. 78.8 Pad El. 78.8 Pad El. 78.8 Pad El. 78.8 Slope @ Pad El. 78.8 Hilltop St 11 + 10 -11 +40 Pad El. 79.5 Pad E). 79.5 Pad El. 77.5 Pad El. 77.5 Pad El. 75.5 Pad El. 75.5 Pad El. 75.5 Pad El. 75.5 Pad El. 74.0 Pad El. 74.0 Pad El. 72.4 Pad El. 72.4 Summit Trail Court Summit Trail Court Summit Trail Court Pad El. 88.9 Pad El. 87.8 Pad El. 80.7 Pad El. 79.9 Pad El. 78.8 Pad El. 79.5 Pad El. 77.5 Pad El. 76.5 Pad El. 75.5 Pad El. 74.0 Pad El. 72.4 Pad El. 75.5 Pad El. 75.5 Pad El. 75.5 Pad El. 77.1 Pad El. 87.8, Slope Pad El. 79.9, Slope Pad El. 79.5, Slope Pad El. 79.5, Slope Pad El. 78.8, Slope TRACT NO, PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 ELEV OR DEPTH (ft) 73.0 74.0 76.0 76.0 78.0 78.0 71.0 74.0 76.0 78.0 78.0 76.0 76.0 73.5 73.5 74.5 74.5 69.0 73.0 69.0 71.0 69.0 69.5 71.0 88.9 87.8 80.7 79.9 78.8 79.5 77.5 76.5 75.5 74.0 72.4 82.6 82.0 82.0 83.0 74.0 69.0 67.0 65.0 78.0 MOISTURE CONTENT (%) 10.4 10.3 10.2 9.3 9.0 10.8 11.5 11.2 14.8 6.3 10.0 7.2 9.8 10.2 15.3 11.4 14.6 14.8 14.5 14.8 15.1 16.1 14.7 15.6 13.1 13.0 13.3 13.7 9.2 9.5 9.0 9.7 9.4 9.0 9.3 9.4 6.3 9.8 14.5 13.8 12.1 14.2 13.6 13.0 DRY DENSITY (Pd) 123.5 123.7 120.7 118.8 120.0 119.3 115.4 118.1 109.5 110.7 119.1 113.2 118.9 107.2 107.9 105.4 108.3 107.5 107.2 108.8 107.8 107.6 107.1 107.9 109.9 109.4 108.7 109.3 119.4 118.5 119.1 119.8 119.4 118.7 118.4 119.3 117.4 118.4 107.5 110.0 114.2 113.5 109.2 109.5 REL COMP W 93.9 94.0 91.8 90.3 91.3 90.7 91.6 ! 93.0 90.9 84.2 90.6 86.1 90.4 90.1 90.7 88.6 91.0 90.3 90.1 91.4 90.6 90.4 90.0 90.7 91.2 90.8 90.2 90.7 90.8 90.1 90.6 91.1 90.8 90.3 90.0 90.7 89.3 90.0 90.3 91.3 90.6 90.1 90.6 90.9 TESCT METHOD NO ND SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC SC ND ND ND ND ND ND ND ND ND ND ND ND SC ND ND ND ND ND ND ND SOIL TYPE X X X X X X E A C X X X X Y Y Y Y Y Y Y Y Y Y Y C C C C X X X X X X X X X X Y C E E C C Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village File: C:\excel\tablcs\S300\5353b1 .ror.pa21 GeoSoils, Inc. WO. 5353-B1-SC November 2008 Page 4 Table 1 FIELD DENSITY TEST RESULTS TEST NO. 1019'-S 1020'-S 1021'-S 1022'-S 1023'-S 1030 1031 1032 1033 1126 1127 1128 1129 1130 1214* 1214A 1215* 1215A 1216* 1216A 1306-FG 1349 1350 1351 1384 1385 1386 1387 1388 1389 DATE 8/17/07 8/17/07 8/17/07 8/17/07 8/17/07 8/28/07 8/28/07 8/28/07 8/28/07 10/1/07 10/1/07 10/1/07 10/1/07 10/1/07 10/19/07 1/21/08 10/19/07 1/21/08 10/19/07 1/21/08 12/14/07 3/12/08 3/12/08 3/12/08 4/2/08 4/2/08 4/2/08 4/2/08 4/3/08 4/3/08 TEST LOCATION Pad El. 78.8, Slope Pad El. 78.8, Slope Pad El. 78.8, Slope Pad El. 78.8, Slope Pad El. 78.8, Slope Pad El. 86.8 Pad El. 86.8 Pad El. 86.8 Pad El. 86.8 Pad El. 73.9 Pad El. 75.5 Pad El. 77.1 Pad El. 77.1 Pad El. 80.7 Pad El. 82.5 Pad El. 82.5 Pad El. 84.0 Pad El. 84.0 Pad El. 86.8 Pad El. 86.8 Pad El. 77.1 Pad El. 85.4 Pad El. 73.9 Pad El. 82.5 Pad El. 86.8 Pad El. 85.4 Pad El. 85.4 Pad El. 84.0 Pad El. 82.5 Pad El. 82.5 TRACT NO, PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 PA-21 ELEV OR DEPTH (ft) 76.0 74.0 72.0 70.0 75.0 75.0 76.0 78.0 77.0 80.0 78.0 82.0 76.0 85.0 80.5 80.5 80.5 80.5 80.5 80.5 71.0 84.0 81.0 81.5 86.8 85.4 85.4 84.0 82.5 82.5 MOISTURE CONTENT(%} 14.0 13.7 13.6 13.9 13.7 10.3 9.8 9.5 10.8 12.0 11.3 11.8 11.0 11.4 8.2 14.8 8.0 16.7 8.1 15.0 11.8 11.8 14.0 11.5 11.4 11.0 11.7 11.2 11.3 11.0 DRY DENSITY (pelf) 102.8 103.4 104.0 108.5 109.2 122.5 124.1 124.8 123.3 114.8 114.2 113.5 114.4 114.0 109.0 109.4 109.3 108.6 109.4 108.8 119.4 116.1 104.1 111.1 119.5 120.0 119.1 119.9 119.6 120.1 mi COMP (%) 90.2 90.7 91.2 90.0 90.6 91.4 92.6 93.1 92.0 91.1 90.6 90.1 90.8 90.5 90.4 90.8 90.7 90.1 90.8 90.3 90.8 93.6 91.7 90.3 94.8 95.2 94.5 95.1 94.9 95.3 TESCT METHOD NO ND ND ND ND ND ND ND SC ND ND ND ND ND ND ND ND ND ND ND L_ ND ND ND ND ND ND ND ND ND ND SOIL TYPE B B B C C H H H H E E E E E C C C C C C X S BB AA E E E E E E LEGEND: 1 = Repeated Test Number * = Failed Test A = Retest FG = Finish Grade ND = Nuclear Densometer S = Slope SC = Sand Cone Note: Test Locations, noted as based on O'Day (2007). O'Day (2007, Revised 2008) was not available during mass grading. Brookfield San Diego Builders, Inc. PA 21 Robertson Ranch, East Village File: C-\exce!\tab!cs\5300\5353b1 ,ror.pa21 GeoSoils, Inc. W.O. 5353-B1-SC November 2008 PageS TABLE 2 - BUILDING PAD CHARACTERISTICS, PA-21 BLDG. No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 E.I. (ASTM D4829) 69 69 69 69 69 69 69 69 69 69 69 69 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 38 25 25 25 25 EXPANSION POTENTIAL'1' Medium Medium Medium Medium Medium Medium Medium Medium Medium Medium Medium Medium Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low Low LOW SULFATE EXPOSURE12* Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible Negligible PLASTICITY INDEX (PI)'3' 26-32 26-32 26-32 26-32 26-32 25-29 26-32 25-29 25-29 25-29 25-29 25-29 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 16-20 12-16 12-16 APPROX. DEPTH OF FILL (RANGE IN FT.) 3-5 3-5 3-5 3-5 3-5 3-5 3-5 3-5 3-5 5-7 3-7 4-6 20-30 16-38 15-30 27-41 38-41 32-41 3641 39-43 40-44 42-47 32-40 29-35 21-31 32-34 40-45 30-43 26-34 15-27 12-23 13-23 20-30 1 9-30 FOUNDATION TYpEw II II II II II II II II II II II II III HI III III! Ill III 111 III III III HI III III III III III III II II II III III GeoSoils, Inc. APPENDIX REFERENCES American Concrete Institute, 2008, Building code requirement for structural concrete (ACI 318-08) and commentary, an ACI standard reported by AC! Committee 318, dated January. , 2004, Guide for concrete floor and slab construction: reported by ACI Committee 302; Designation ACI 302.1 R-04, dated March 23. American Society for Testing and Materials, 1998, Standard practice for installation of water vapor retarder used in contact with earth or granular fill under concrete slabs, Designation: E 1643-98 (Reapproved 2005). , 1997, Standard specification For plastic water vapor retarders used in contact with soil or granular fill under concrete slabs, Designation: E 1745-97 (Reapproved 2004). California Building Standards Commission, 2007, California building code. Caltrans, 1999, Interim corrosion guideline for foundation investigations, Corrosion and Technology Section, Office of Materials and Foundations, dated May. Carlsbad, City of, 1993, Standards for design and construction of public works improvements in the City of Carlsbad. GeoSoils, Inc., 2008, Geotechnical update of seismic design criteria for Robertson Ranch, East Village, City of Carlsbad, San Diego County, California, W.0.5353-B-SC, dated March 17. , 2007a, Compaction report of geotechnical observation and testing services, 84-inch storm drain improvements for Cannon Road, Robertson Ranch East Village, Carlsbad, San Diego County, California, Carlsbad, San Diego County, California, W.O. 5355 D-SC, dated August 16. , 2007b, Updated geotechnical evaluation of the Robertson Ranch, East Village Development, Carlsbad Tract 02-16, Drawing 433-6, Carlsbad, San Diego County, California, W.O. 5353-A-SC, dated January 15. , 2006a, Supplemental recommendations regarding pier supported bridge abutments, Robertson Ranch East Project, City of Carlsbad, San Diego County, California, W.O. 3098-A2-SC, dated November 30. , 2006b, Memorandum: update of the geotechnical report with respect to site grading and the current grading plan, Robertson Ranch East, City of Carlsbad, W.O. 3098-A2-SC, dated November 15. GeoSoils, Inc. , 2006c, Memorandum: discussion of earthwork recommendations in the vicinity of a planned 84-inch storm drain, Cannon Road, Stations 127+- to 136+32, Improvements for Robertson Ranch East, City of Carlsbad, California, W.O. 3098-A2-SC, dated July 28. , 2006d, Supplement to the update geotechnical evaluation regarding the distribution of wick drains, Robertson Ranch East, Carlsbad, San Diego County, California, W.O. 3098-A-SC, dated June . _, 2006e, Report of rough grading, Calavera Hills II, College Boulevard and Cannon Road Thoroughfare, District No. 4 (B&TD), Carlsbad Tract 00-02, Drawing 390-9A, Carlsbad, San Diego County, California, W.O. 3459-B2-SC, dated January 27. , 2004, Updated geotechnical evaluation of the Robertson Ranch property, Carlsbad, San Diego County, California, W.O. 3098-A2-SC, dated September 20. , 2002, Geotechnical evaluation of the Robertson Ranch property, City of Carlsbad, San Diego County, California, W.O. 3098-A1-SC, dated January 29. , 2001 a, Preliminary findings of the geotechnical evaluation, Robertson Ranch Property, City of Carlsbad, California, W.O. 3098-A-SC, dated July 31. , 2001 b, Preliminary geotechnical evaluation, Calavera Hills II, College Boulevard and Cannon Road Thoroughfare, District No. 4 (B&TD), City of Carlsbad, California, W.O. 2863-A-SC, dated January 24. Kanare, Howard, 2005, Concrete floors and moisture, Portland Cement Association, Skokie, Illinois. Nichols, Herbert L, Jr., 1976, Moving the Earth, The Workbook of Excavation, 3rd Edition, McGraw-Hill Publishing Company. O'Day Consultants, 2007, Grading plans for Robertson Ranch PA 21, revised date October 2008. Project Design Consultants, 2007, Alluvial shots to date, 5/09/2007, Robertson Ranch, Job No. 3481. Romanoff, M., 1957, Underground corrosion, National Bureau of Standards Circular 579, Published by National Association of Corrosion Engineers, Houston, Texas, reprinted 1989. State of California, Department of Transportation, 2006, Highway design manual of instructions, sixth edition, September printing. Brookfield San Diego Builders, Inc. Appendix Hle:e:\wp9\S300\5353b1.ror.pa21 Page 2 GeoSoils, Inc. *f i: I ':^^'^ W'-.J 111''!"',' ,' •' liS^J-M "* r I* [ \ +*$&' '^ftk— 1' i rr \ / r3n iS jj.7 TW \ / rrri • rCSE^^^PT^^S ' ' <L - vi-'-iU-r VS^ (ft' J, «-: '-' 7t>n--_,-'f^ ^ '•»,. f, —^ '- !* * ""ffl =ri r-^^irtt^^^ AS-GRADED GEOTECHNICAL MAP (D2006 O'Daj Consultoils. Inc i^/^i] Zr^V"-!--v J" AS-GRADED GEOTECHNICAL MAP PA21 . -•'.... i-'i .. , Iff —Lf~ w , wv " - - t * -"rrH- •---!-- -t- »—'I ^*-|«J B' ^ /z»X5 or mas\ ACiwi oufMsms Mr WRY ONI caeaucooN DOCU&TS BUT mi' OC H SUBSTAMMM. COftmtMCt. ALL LOCATIONS ARE APPROXMATE SECTION T-fmsou BENCHMARK: Inc.RIVERSIDE CO. ORANGE CO. SAN DIEGO CO. AS-GRADED GEOTECHNICAL MAP PA21 WX>. W63-8-SC MTE 11A6 KALE CONSULT ©2006 O'Dcy Conwltixiti, Inc. :;™^ ,. ~L. 1 - ' ' ' 'ji x-«i _*."s aw HMOMCSraces at mu.sATAM/ OUEHSOKS UAf WHY ONoocuaus aur uu.- M SUKU*Mt __ OOT. omf*t mnu-s BENCHMARK: DExnptim s'MDMb v-tp sixff cfif/ SECTION 'G-G' ALL LOCATIONS ARE APPHOXMATC RIVERSIDE CO. ORANGE CO. SAN DIEGO CO. AS-GRADED GEOTECHNICAL MAP PA21 nice acu£