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HomeMy WebLinkAboutCT 04-26; ROBERTSON RANCH EAST VILLAGE PA 16, 17, & 18; REPORT OF ROUGH GRADING; 2009-02-161 .1 REPORT OF ROUGH GRADING PLANNING AREA 16 OF ROBERTSON RANCH, EAST VILLAGE CARLSBAD SITE DEVELOPMENT PLAN 04-26 DRAWING 453-8A, CARLSBAD SAN DIEGO COUNTY, CALIFORNIA FOR BROOKFIELD SAN DIEGO BUILDERS, INC. 12865 POINTE DEL MAR, SUITE 200 SAN DIEGO, CALIFORNIA 92014 W.O. 5353B1-SC FEBRUARY 16, 2009 C. cdoslQw --.._ Geotechnical Geologic Coastal Environmental 5741 Palmer Way Carlsbad, California 92010 (760) 438-3155 FAX (760) 931-0915 February 16, 2009 K.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 16 of Robertson Ranch, East Village (Lots 44 through 63, 89 through 99, 117 through 140, and 160 through 189.) Carlsbad Tract 04-26, Drawing 453-8A, Carlsbad, San Diego County, California Dear Ms. McHugh: This report presents a summary of the geotechnicat testing and observation services provided by GeoSoils, Inc. (GSI) during the rough earthwork construction phase of development associated with the development of Planning Area 16 (PA-1 6) 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 March 2007, and was generally completed in October 2008. PURPOSE OF EARTHWORK The purpose of grading was to prepare building pads and associated street areas for the construction of 109 single-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 terrace deposits/formational material were removed to suitable earth material (as defined in the approved report for the site), and either exported from the site or recompacted as fill. Rough grading is generally completed throughout PA-16. The approximate limits of grading under the purview of this report are shown on the Geotechnical Maps (Plates 1 and 2), which use the 40-scale grading plan for this project, prepared by O'Day Consultants (2008), 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 surficial deposits of colluvium (topsoil), and alluvium, underlain by terrace deposits (considered bedrock), and formational sediments belonging to the Santiago Formation (also considered bedrock). The subsurface conditions exposed were generally as anticipated per our approved geotechnical report (GSI, 2007b). 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 G'Sl (2004 and 2007b). GROUNDWATER Groundwater was not encountered during site grading within this planning area. 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. Toe drains were constructed locally (see Plates 1 and 2) in order to mitigate anticipated perched water conditions along the toe of the slopes. However, perched groundwater conditions may develop in the future due to rainfaU, excess irrigation, homeowner altered drainage, or damaged utilities, and should be anticipated along cut/fill contacts, zones within compacted fill with contrasting permeabilities, or in cut areas where low permeability sediments/bedrock soils occur at, or near the surface. Should manifestations of perched conditions (i.e, seepage, or ponding), develop in the future, this office should assess the conditions and provide mitigative 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, 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 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1.ror.pal6 Page 2 GeL, be0 Rough Grading Preparation of Existing Ground 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. 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. Lots containing cut/fill transitions, and lots containing non-uniform native soil conditions, 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. Approximate as-built fill depths across any given lot are 'shown in Table 2: 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 and 2, was observed by a representative of GSI. Plates 1 and 2 utilize the 40-scale grading plan (Sheets 10 and 13, DWG 453-8A), prepared by O'Day Consultants (2008), as a base map. Fill Placement Fill consisted of onsite and import materials which were placed in thin lifts, approximately 4t0 8 inches in thickness, brought to at least optimum moisture content, and compacted to attain a minimum 90 percent relative compaction. 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. Slopes Graded Slopes Graded slopes constructed under the purview of this report are generally on the order of 10 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). Brookfield San Diego Builders, Inc. W.O. 5353-81-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp8\5300\5353b1 .ror.pal6 Page 3 Ge, Inc. Fill slopes, constructed under the purview of this report, were provided with abasal bench, or keyway, excavated into suitable earth material in general accordance with the approved GSI recommendations Cut slopes were constructed using cut and fill grading techniques in general accordance with the approved GSI recommendations (GSI, 2007b), and exposed suitable formational earth material(s). As a result of recent rain storms during the winter of 2007/2008, and 2008/2009, some surficiàl erosion of the site slopes was observed. Prior to improvements construction, the. site should be reviewed by the geotechnical consultant and recommendations provided for slope repair, as necessary. Typical recommendations may include, but not be limited to, the removal/recompaction of loose soil, moisture conditioning, and additional compactive effort applied to the slope face. Site soils, and soils comprising slopes, are considered erosive. Temporary Slopes Any proposed/future temporary construction slopes may be constructed at a gradient of 1:1 (horizontal:vertical [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 thO 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 5 feet from the top of any temporary slope. 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-16 Subd ra inage "Toe drains" were constructed (per GSI, 2007b) throughout PA-16, and are shown schematically on Plates 1 and 2. These drains are planned to outlet into future, planned storm drain systems, however, at present, these drains are "stubbed out" via a vertical riser and must be connected to the storm drain system prior to foundation construction. General toe drain recommendations, and schematics, are presented in a later section .of this report Surveys performed on toe drain subdrain pipes were provided in the field by the project surveyor (Project Design Consultants, 2008). Canyon subdrain systems were provided within the two main canyons trending through the site in the vicinity of Lots 91, 125, and 132, and southeast of Lot 99 (see Plate 2). These drains ultimately outlet into existing storm drain systems located offsite. Brookfield San Diego Builders, Inc. W.O.5353-B 1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353h1 .ror.pal6 Page 4 GeoSs Inc. 11 Field Testing Field density tests were performed using the sand-cOne method (ASTM D 1556) and nuclear (densometer) method (ASTM D 2922, D 3017). Tests taken for the Robertson Ranch project were taken in consecutive numerical order. Only tests within the subject site, under the purview of this report, are presented in Table 1 at the end of the text. The approximate locations of field density tests are shown on the Geotechnical Maps (Plates 1 and 2), which utilize the 40-scale grading plan (Sheets 10 and 13, DWG. 453-8A), prepared by O'Day Consultants (2008), as a base map. 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. 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 fora given density test. Testing and observations were performed on a full- and part-time basis, as solely determined by the general contractor. LABORATORY TESTING Moisture-Density Relations The laboratory maximum dry density and optimum moisture content for each major soil type was determined in general accordance with test method ASTM D 1557. The following table presents the test results: SôIL1i'PE .' ; .MAxIUM DRY. DENSITY (pcf) OPTIMUM MOISTURE CONTENT A - Brown, Silty SAND 127.0 10.0 B - Dark Brown, Clayey SAND 114.0 13.0 C - Gray Brown, clayey SAND 120.5 13.0 E - Dark Brown, Silty SAND 126.0 11.0 F - Gray Brown Gravelly SAND 134.0 8.0 J - Gray Clayey, SAND 121.0 12.5 Brookfield San Diego Builders, Inc. W.O. 5353-81-Sc PA 16 Robertson Ranch, East Village February 16, 2009 Fi1e:e:\wp9\5300\5353b1 .ror.pal6 Page 5 GeoSiwiJs9 Inc. MAXIMUM DRY OPTIMUM MOISTURE :cOrrErr(°,) K- Dark Gray, CLAY 102.0 21.0 L - Olive Brown, Silty CLAY 111.0 18.5 M - Yellow Brown, Silty SAND (import) 123.0 13.0 0 - Yellow Brown, Clayey SAND (import) 119.5 11.5 P - Yellowish Brown, Clayey SAND (import) 124.5 10.5 Expansion Index Expansion Index (El) tests were performed for the representative foundation soil types exposed near-finish grade in general accordance with ASTM D 4829 in groups of about three to five lots, or if there was a significant change in expansive character. The E.I. test results are 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, site soils are considered to range from negligible (sulfate class SO), to moderate (sulfate class Si) with respect to water soluble sulfate exposure to concrete, per Table 4.2.1 and 4.3.1 of the American Concrete Institute (ACI) document 318-08 (California Building Code [CBC], California Building Standards Commission [CBSC], 2007). Site specific soil sulfate classifications are presented in Table 2. Soils are relatively neutral with respect to soil acidity/alkalinity (pH range of 6.8 to 7.6) (Romanoff, 1989), and are very corrosive to exposed ferrous metals in a saturated state (saturated resistivity <1,000 ohm-cm). The chloride ion content in soil was also noted to generally be below action levels (300 ppm) per Caltrans (1999), for a majority of the lots; however, Lots 121 through 127, and Lots 136 through 140 were evaluated to have chloride ion levels on the order of 500 to 600 ppm, and should be protected accordingly. 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 piping, etc. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\vip9\5300\5353b1.ror. pal 6 Page 6 GeoSoils, Inc. 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 - CONVENTIONAL FOUNDATIONS General The foundation design and construction recommendations are based on laboratory testing and engineering analysis of onsite earth materials by GSl. Recommendations for conventional, and post tensioned foundation systems are provided in the following sections. The foundation systems may be used to support the proposed structures, provided they are founded in competent bearing material. Foundations should be 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.1.) 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 P1 >15, this implies that the Code may require the use of more onerous foundations (i.e., post-tension, mat, etc.).. Where alluvium has been left- in-place, post-tension foundations are required. The information and recommendations presented in this section are not meant to supercede design by the project structural engineer. Upon request, GSl could provide additional input/consultation regarding soil parameters, as related to foundation design. 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-built conditions, general recommendations for minimal foundation design and construction are presented below. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1.ror.pal6 Page 7 GeS, Bearing Value 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. 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 isrecommended 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 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. 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 2,5,00 psf. 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. ifferential Settlement All 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. 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 US.G.S. The short spectral response uses a period ol 0:2 seconds. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1 .10rpa16 Page 8 !nc CBC SEISMIC DESIGN PARAMETERS.FOR SITECLASS "D"SOILS PARAMETER 'VALUE IcBc:REFEnENcE Site Class 0 Table 1613.5.2 Spectral Response- (0.2 sec), S 115g Figure 1613.5(3) Spectral Response - (1 sec) S, 0.44g Figure 1613.5(4) Site Coefficient, F. 1.04 Table 1613.5.3(1) Site Coefficient, F 156 Table 1613.5.3(2) Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec) SMS 1.20g Section 1613.5.3 (Eqn 16-37) Maximum Considered Earthquake Spectral Response Acceleration (1 sec), SM1 0.68g Section 1613.5.3 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (0.2 sec), S 0.79g Section 1613.5.4 (Eqn 16-39) 5% Damped Design Spectral Response Acceleration (1 sec), S.,, 0.46g 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. W. 0. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1 .ror.pal6 Page 9 GeoSis, Inc. 'C9N(ENT19NAL PERiitETE OPTINGS.A .SLADS,]IQBERTSpN RANCH EAST VILLAG.E:i777771 L U N MIN TERIOR MIN MIN INTERIOR MIN , MIN EXTERIOR ICATEGORY FOOTING 1'5L.AB REINFORCING SLAB UNDER-SLAB GARAGE SLAB FLATWORK -:STEEL: 'EINFORCE NT. REINFORCEMENT REINFORCING Tli~I(NESS 12'W 1-No. 4 Bar No.3 Bars @ 18. 2" Sand Over 10-Mil vapor 6" x 6" 12 Deep 4 Thick Top and Bottom o.c. Both Directions retarder Over 2" Sand (10/10) welded wire None Base fabric (WWF) 2" Sand Over 10/1 5-Mil 6"x 6" 12" Wide x 2-No. 4 Bars No.3 Bars @ 18 vapor retarder Over 2" (6/6) WWF. or 6" x 6" 18 Deep 4" Thick Top and Bottom o.c. Both Directions Sand Base (1 5-milfor No.3 Bars @18" 10x10 WWF medium expansive soils o.c Both Directions only) for Low 2" Sand Over 15-Mi) vapor 111 12"'Widex Thick 2-No5Bars No. 3 Bars @18" retarder Over 3"Sand Same as 6"x6" 24" Deep lop and Bottom o.c. Both Directions Base (highly expansive Interior Slab (616) WWF soils only) IV PT ONLY PT ONLY 1 PT ONLY PT ONLY PTONLY I PT ONLY PTONLY Category Criteria Category I: Max. Fill Thickness is less than 20' and E.I. is less than, or equal to, 50 (P.1. <15) and Differential Fill Thickness is less than 10' (see Note 1). Category If: Max. Fill Thickness is less than 30' or E.I. is less than, or equal to, 90 or Differential Fill Thickness is between 10 and 20' (see Note 1). Presoaking required. Category Ill: Max. Fill Thickness exceeds 30', or E.I. exceeds 90 but is less than 130, or Differential Fill Thickness exceeds 20' (see Note 1). Presoaking required. Category IV: Very Highly Expansive soil conditions (Expansion Index greater than 130). Post-tension foundations only. Notes: 1. Conventional foundations shall also be designed per Section 1805A.8, Chapter 18 of the CBC (CI3SC. 2007) where the P.I. is 15, or greater. Post-tension foundations are required where maximum fill exceeds 30', or the ratio of the maximum fill thickness to the minimum fill thickness exceeds 3:1, or where the E.I. exceeds 90, or inareas underlain with alluvial soil left in place. Differential settlements discussed in the body of the report should be incorporated into foundation design by the structural engineer/slab designer. Footing depth measured Irom lowest adjacent compacted/suitable subgrade. The allowable soil bearing pressure is 2,000 psf. Concrete for slabs and footings shall have a minimum compressive strength of 2,500 psi 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 E.I. >90. The vapor retarder 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). Isolated footings shall be connected to foundations per soils engineer's recommendations (see report). B. Sand used for base under slabs shall be a "clean" granular material, and have SE >30. 'Pea" gravel may he substituted for the basal sand layer in order to improve water transmission mitigation. Additional exterior flatwork recommendations are presented in the text of this report. 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. Pre-welting is recommended for all soil conditions as follows: very low 1010w expansive (at least optimum moisture content to a depth of 18 inches, medium expansive (at least 2-3% over optimum to a depth 0118 inches), highly to very highly expansive (at least 4-5% over optimum to a depth of 24 inches). POST-TENSIONED 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. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1.ror. pal 6 Page 10 GeoScUs, Inc. 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 (PTl) Method (31d Edition). Alternatives to the PTI method may be used if equivalent systems can be proposed which 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 VERY LOW MEDIUM HIGH VERY HIGH POTENTIAL (E 1=050) (E I = 51 90) (El = 91 130) (E I >130) e0, center lift 9.0 feet 8.7 feet 8.5 feet 7.5 feet e edge lift 5.2 feet 4.5 feet 4.0 feet 3.25 feet y, center lift 0.3 inches 0.49 inches 0.66 inches 1.1 inches y0 edge lift 0.7 inch 1.3 inch 1.7 inches 2.5 inches Bearing Value 1,000 psf 1,000 psf 1,000 psf 1,000 psf Lateral Pressure 250 psf 250 psf 250 psf 250 psf Subgrade Modulus (k) 100 pci/inch 85 pci/inch 70 pci/inch 60 pci/inch Foundation Category Category I PT Category II PT Category Ill PT Category IV PT per GSI (2007b, see Reference) Minimum Perimeter Footing Embedment 12 nches inches 18 inches 24 inches 30 inches Internal bearing values within the perimeter of the post-tension slab may be increased to 2,000 psf for a minimum embedment of 12 inches, then by 20 percent for each additional foot of embedment to a maximum of 3,000 psf. 121As measured below the lowest adjacent compacted subgrade surface. Note: The use of open bottomed raised planters adjacent to foundations will require more onerous design parameters. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1 .ror.pal6 Page 11 GeoSoils, Inc. 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. 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 above. Pie-wetting of the slab subgrade soil prior to placement of steel and concrete will likely be recommended and necessary, in orderto achieve optimum moisture conditions. Soil moisture contents should be evaluated at least 72 hours prior to pouring concrete. If pie-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.l. of 50, or less), the floor slab should be underlain with 2 inches of sand, over a lO-mil polyvinyl membrane Brookfield San Diego Builders, Inc. W.O. 5353-131-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1 .ror.pal6 Page 12 tSwk, Inc. (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 [GSl, 2004]), and constructed in accordance with ACI 302.1 R-04. All vapor retarders should be. placed per ASTM F 1745 and the CBC (CBSC, 2007). Medium Expansive Soils For floor slabs bearing on medium expansive soil subgrades (E.l. 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. All vapor retarders should be placed per ASTM E-1 643 and the CBC (CBSC, 2007). 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. Highly to Very Highly Expansive Soils For floor slabs bearing on highly to very highly expansive soil subgrades (E.l. greater than 90), the slab should be underlain with 2 inches of pea gravel (SE >30), over a 15-mil vapor retarder, over a minimum 2-inch pea gravel base. The water/cement ratio of the concrete shall not be more than O.S. All vapor retarders should be placed per ASTM E-i 643 and the CBc (CBSC, 2007). 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 Brookfield San Diego Builders Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 Fi1e:e:\wp9\5300\5353b1 .ror.pal6 Page 13 oSk9 Inc. 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. Additionally, as indicated in GSl (2007b), site soils are considered moderately to highly erosive. This condition should be considered prior to, and during any future development. 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 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 upon the laboratory testing, site soils are considered to range from negligible (sulfate class SO), to moderate (sulfate class Si) with respect to water soluble sulfate exposure to concrete, per Table 42.1 and 43.1 of the American Concrete Institute (ACI) document 318-08 (California Building Code [CBC], California Building Standards Commission [CBSC], 2007). Site specific soil sulfate classifications are presented in Table 2. Soils are relatively neutral with respect to soil acidity/alkalinity (pH range of 68 to 7.6) (Romanoff, 1989), and are very corrosive to exposed ferrous metals in a saturated state (saturated resistivity <1,000 ohm-cm). The chloride ion content-in soil was also noted to generally be below action levels (300 ppm) per Caltrans (1999), for a majority of the lots, however, Lots 121 through 127, and Lots 136 through 140 were evaluated to have chloride ion levels on the order of 500 to 600 ppm, and should be protected accordingly. 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 piping, etc. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1 .ror.pal6 Page 14 GS@iLc, Inc. 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, 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 loading, per Table 1610.1 of the CBC (2007) for USCS soil classification SM-SC. For areas of male or reentrant 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. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1 .ror.pa16 Page 15 GSoUs, Inc. 'suflFACE RETAINED MATERIAL WEIGHT P CF (SELECT WEIGHT P C F (HORIZONTAL VERTICAL)' PRE-APPROVED BACKFILL**) (NATIVE BACKFILL*) Level* 35 45 2tol 50 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. El. <50, SE >20. and P1 <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 geofabric 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 ½-inch to 3/4-inch gravel wrapped in approved filter fabric (Mirafi 140, or equivalent) should be used behind 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 El 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.l. <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. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 FiIe:e:\wp9\5300\5353b1 .ror.pal6 Page 16 GeoSeils, Inc. 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 minimum of a 2-foot overexcavation and recompaction of cut materials for a distance of 2H, from the point of transition. Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints or crack control joints) such that a angular distortion of 11360 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 aflexible, non-shrink grout. C) Embed the footings entirely into native formational material (i.e., deepened footings). 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. Brookfield San Diego Builders, Inc. W.0. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 Fi1e:e:\wp9\5300\5353b1.rorpa16 Page 17 GeoSoik, Inc. 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- 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. 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 prior to pouring concrete. lf.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. 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. 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 Brookfield San Diego Builders, Inc. W.O. 5353-81-SC PA 16 Robertson Ranch, East Village February 16, 2009 File :e:\wp9\5300\5353b1 .ror.pal6 Page 18 GeSh, Inc. 1 Ofeet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from thefoundations and sidewalks with expansion/shrinkage joint filler material. 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. 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. Planters and walls should not be tied to the house. 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. 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. Positive site drainage should be maintained at all times. Finish grade on the lots 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. 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. 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. Brookfield San Diego Builders, Inc. W.O.5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1 .ror.pals Page 19 GeSos, Inc. 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 A-value data estimated for the area. Parking Lot Stalls/Cul De Sac! 4.5 9 4.0 5.0 Low Traffic Private Streets Private Streets 5.0 9 4.0 7.0 1(1) Denotes Class 2 Aggregate Base "R"~78, SE >25). I Final pavement sections shall be based on site specific A-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. 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 ([FE). 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 thelife 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) Brookfield San Diego Builders, Inc. W.O. 5353-131-SC PA 16 Robertson Ranch, East Village February 16, 2009 'File: e:\wp9\5300\5353b1.ror.pal6 Page 20 GeoSoils, Inc. 13 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 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 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 LEE 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 [FE. 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 (ie., 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 Brookfield San Diego Builders, Inc. W.O. 5353-B 1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1 .ror.pal6 Page 21 Ge$oHs9 Inc. 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 otherfibrous 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 landscaping. Drainage Adequate lot 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. Lot 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 lots 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. 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. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1.ror. pal 6 Page 22 GeoSoils, Inc. 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 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. Toe-of-Slope Drains/Toe Drains Where significant slopes intersect pad areas, surface drainage down the slope allows for some seepage into the subsurface materials, sometimes creating conditions causing or contributing to perched and/or ponded water. Toe-of-slope/toe drains may be beneficial in the mitigation of this condition due to surface drainage. The general criteria to be utilized by the design engineer for evaluating the need for this type of drain is as follows: Is there a source of irrigation above or on the slope that could contribute to saturation of soil at the base of the slope? Are the slopes hard rock and/or impermeable, or relatively permeable, or; do the slopes already have or are they proposed to have subdrains (i.e., stabilization fills, etc.)? Was the lot at the base of the slope overexcavated or is it proposed to be overexcavated? Overexcavated lots located at the base of a slope could accumulate subsurface water along the base of the fill cap. Arethe slopes north facing? North facing slopes tend to receive less sunlight (less evaporation) relative to south facing slopes and are more exposed to the currently prevailing seasonal storm tracks. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 Fi1e:e:\wp9\5300\5353b1 .ror.pal6 Page 23 Ges, Inc. What is the slope height? It has been our experience that slopes with heights in excess of approximately 10 feet tend to have more problems due to storm runoff and irrigation than slopes of a lesser height. Do the slopes "toe out" into a residential lot or lot where perched or ponded water may adversely impact its proposed use? Based on these general criteria, the construction of toe drains may be considered by the design engineer along the toe of slopes, or at retaining walls in slopes, descending to the rear of such lots. Following are Detail 1 (Schematic Toe Drain Detail) and Detail 2 (Toe Drain Along Retaining Wall Detail). Other drains may be warranted due to unforeseen conditions, homeowner irrigation, or other circumstances. Where drains are constructed during grading, including subdrains., the locations/elevations of such drains should be surveyed, and recorded on the final as-built grading plans by the design engineer. It is recommended thatthe above be disclosed to all interested parties, including homeowners and any homeowners association. Toe drains were constructed at the completion of grading in general accordance with the recommendations provided by this office The approximate locations of toe drains constructed are shown on Plates 1 and 2. These drain are presently "stubbed out" and will require connections to the storm drain system once, it is installed. 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. Brookfield San Diego Builders, Inc. W.O. 5353-BI-SC PA 16 Robertson Ranch, East Village February 16, 2Q09 Filc:e:\wp9\5300\5353b1.ror.pal6 Page 24 GeoSofls, Inc. Pad grade / Drain pipe Drain may be constructed into, or• at, the toe-of-slope Soil cap compacted to 90 percent relative compaction. Permeable material may be gravel wrapped in filter fabric (Mirafi 140N or equivalent). 4-inch--diameter, perforated pipe (SDR-35 or equivalent) with perforations down. Pipe to maintain a minimum 1 percent fall. Concrete cut-off wall to be provided at transition to solid outlet pipe. Solid outlet pipe to drain to approved area. Cleanouts are recommended at each property line. I SCHEMATIC TOE DRAIN DETAIL Detail 1 Mirafi 140. filter fabric or equivalent nch crushed gravel -I Ret Finish grad Wall fo 2:1 (H:V) slope (typical) Backfill with compacted native soils Top of wall 1to2feet-' -- inches i NOTES: Soil cap compacted to 90 percent relative compaction. Permeable material may be gravel wrapped in filter fabric (Mirafi 140N or equivalent). 4-inch7diameter, perforated pipe (SDR-35 or equivalent) with perforations down. Pipe to maintain a minimum 1 percent fall. Concrete cut-off wall to be provided at transition to solid outlet pipe. .6. Solid outlet pipe to drain to approved area. Cleanouts are recommended at each property line. Effort to compact should be applied to drain rock. RETAINING WALL DETAIL Detail 2 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 backfllling after rough grading has been completed. This includes any grading, utility trench and retaining wall .backfills, flatwork, etc Additional Grading This office should be notified in advance of any fill placement, supplemental regrading of the site, or trench backlilling 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-1 8. However, the area of the site is only "sheet" graded in the vicinity of Lots 195 through 206, due to the presence of large stockpiles of aggregate base, and other rock products generated during mass grading. Upon removal of these stockpiled materials additional grading will be necessary to bring these lots to the desired grades. Earth materials used to complete these lots shall be compatible with existing, as-built soil conditions described in Table 2. 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. 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 206 through 218,233 through 259,268 through 304, and 309.may require overexcavation for the pool shell due to the presence of fill with a high percentage of rock fragments at depths potentially as shallow as 5 feet below pad grade. Overexcavation depths should be reviewed on a lot by lot basis, as plans are developed. The equivalent fluid pressure against a cantilever wall free to yield at the top, may minimally be assumed as 62 pcf. Brookfield San Diego Builders, Inc. - W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1 .ror.pal6 Page 27 GeoSik, 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. 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. 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. An allowable coefficient of friction between soil and concrete of 0.35 may be used with the dead load forces. When combining passive pressure and frictional resistance, the passive pressure component should be reduced by one-third- 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). All aspects of construction should be reviewed and approved by the geotechnical consultant, including during excavation, prior to the placement of any additional fill, prior to the placement of any reinforcement or pouring of any concrete. Where pools are planned near structures, appropriate surcharge loads need to be incorporated into design and construction by the pool designer. 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). The pool structure should be set back from any adjacent descending slope in accordance with the CBC (CBSC, 2007). 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 Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 Fi1e:e:\wp9\5300\5353b1 .ror.pal6 Page 28 GeSils, Inc. 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 minimizethe effects of expansive soils, soils placed above the undercut should be low expansive (E.l. <50). Hydrostatic pressure relief valves should be incorporated into the pool and spa designs. Apool under-drain system should also be considered, with an appropriate outlet for discharge, depending on pool location. 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. An elastic expansion/shrinkage joint (waterproof sealant) should be installed to prevent water from seeping into the soil at all deck joints. Reinforced grade beams should be placed around skimmer inlets to, provide support and mitigate cracking around the skimmer face. Pool decking/f latwork should be pre-wet/pre-soaked per the Foundation Section of this report. 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 construption. 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 atthattime. 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 trench 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. Brookfield San Diego Builders, Inc. W.O. 5353-Bl-SC PA 16 Robertson Ranch, East Village February 16, 2009 FiIe:e:\wp\5300\5353b1ror.pa16 Page 29 GeSUs, Inc. Utility Trench Backfill 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. 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. All trench excavations should conform to Cal-OSHA and localsafety codes. 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. Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 Fi1e:e:\wp9\5300\5353b1.ror.pa1 Page 30 GSk, Inc. 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 sales documents to homeowners/homeowners associations for geotechnical aspects, including irrigation practices, the conditions 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 order to 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. Brookfield San Diego Builders, Inc. W.O.5353-B1SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353h1 .ror.pal6 Page 31 Ges, Inc. 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. 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. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File: e:\wp9\5300\5353b1 .ror. pal 6 Page 32 Inc. The opportunity to be of service is sincerely appreciated If you should have any questions, please do not hesitate to call our office. Respectfully submitted, GeoSoils, Inc. /ac;> No. 1,934 \ OFEj0 (cf Cerflfied CE 4785 Robl Crismar \tJ David W. Skelly Engineering Geologi Civil Engineer, RC C,vtJ Reviewed by:co F ?. I) (i 134 .O I / J eenno ohn P. Franklin €GeologiW - (jE g ngineering Geolo CA R G C/ATG/D WS/J PF/jh Attachments: Table 1 - Field Density Test Results Table 2 - Lot Characteristics Appendix - References Plates 1 and 2 - As-Graded GeOtechnical Maps Distribution: (4) Addressee Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 16, 2009 File:e:\wp9\5300\5353b1 .ror.pa16 Page 33 GeoSs, Inc. Table 1 FIELD DENSITY TEST RESULTS TEST NO DATE TEST: LOCATION. TRACT NO ELEV. OR MOISTURE CONTENT DR' DENSITY COMP METHOD SOIL TYPE 78 4/20/07 Lot 310 PA-16 48.0 15.8 102.6 90.0 ND 13-- 83 4/20/07 Lot 310 PA-16 51.0 13.8 111.1 91.8 ND J 92 4/23/07 Lot 310 PA-16 56.0 18.6 100.9 90.9 ND L 94 4/23/07 Lot 310 PA-16 56.0 19.7 99.9 90.0 SC L 111 4/24/07 Lot 310 PA-16 60.0 18.9 100.6 90.6 ND L 112 4/24/07 Lot 310 PA-16 61.0 20.0 100.7 90.7 REL......ST ND L 113 4/24/07 Lot 310 PA-16 63.0 19.1 101.5 91.4 ND L 114 4/24/07 Lot 310 PA-16 63.0 13.6 109.7 90.7 SC J 171 5/1/07 Lot 90 PA-16 62.0 21.0 100.2 90.3 sc L 172 5/1/07 Lot 91 PA-16 62.0 19.7 100.8 90.8 ND L 173 5/1/07 Lot 92 PA-16 63.0 18.9 100.6 90.6 ND L 174 5/1/07 Lot 91 PA-16 65.0 24.6 93.8 92.0 ND K 175 5/1/07 Lot 90 PA-16 65.0 21.7 91.8 90.0 ND K 176 5/1/07 Lot 92 PA-16 6.5.0 22.4 92.4 90.6 SC K 243 5/7/07 Glen Ave 16+50 PA-16 68.0 14.6 102.6 90.0 ND B 247 5/8/07 Glen Ave 15+50 PA-16 72.0 12.5 109.5 90.5 ND J 250 5/8/07 Glen Ave 16+00 PA-16 77.0 13.7 110.4 91.2 SC J 270 5/10/07 Lot 89 PA-16 70.0 13.3 102.9 90.3 ND B 271 5/10/07 Lot 89 PA-16 70.0 13.0 104.0 91.2 ND B 272 5/10/07 Lot 90 PA-16 69.0 14.1 103.4 90.7 ND B 273 5/10/07 Lot 90 PA-16 68.5 11.2 114.7 90.3 ND A 274 5/10/07 Lot 91 PA-16 70.0 13.7 108.7 90.2 SC C 275 5/10/07 Lot 91 PA-16 70.0 13.0 102.6 90.0 ND B 276 5/10/07 Lot 89 PA-16 72.0 14.0 104.2 91.4 ND B 277 5/10/07 Lot 90 PA-16 725 14.2 103.3 90.6 ND B 278 5/10/07 Lot 91 PA-16 72.0 13.0 109.3 90.7 ND C 279 5/10/07 Lot 92 PA-16 73.0 13.3 108.5 90.0 sc C 280 5/10/07 Lot 89 PA-16 76.5 10.4 115.4 90.9 ND A 281 5/10/07 Lot 90 PA-16 77.0 13.1 109.7 91.0 ND C 282 5/10/07 Lot 91 PA-16 78.0 14.2 102.9 90.4 ND B 283 5/10/07 Lot 89 PA-16 76.5 10.7 114.6 90.2 ND A 284 5/10/07 Lot 310 PA-16 65.0 10.8 115.4 90.9 SC A 285 5/10/07 Lot 310 PA-16 58.0 11.7 114.7 90.3 ND A 286 5/10/07 Lot 173 PA-16 62.0 10.4 116.3 91.4 ND A 287 5/11/07 Lot 310 PA-16 68.0 14.0 110.1 91.4 ND C 288 5/11/07 Lot 310 PA-16 68.0 13.1 108.7 90.2 ND C 289 5/11/07 Lot 310 PA-16 69.0 13.9 112.1 93.0 SC C 290 5/11/07 Lot 178 PA-16 68.0 13.6 109.2 90.6 ND C 291 5/11/07 Lot 310 PA-16 70.0 14.1 109.1 90.5 ND C 292* 5/11/07 Lot 176 PA-16 73.0 20.5 99.9 90.0 ND L 292A 5/11/07 Lot 176 PA-16 73.0 18.7 101.5 91.4 SC L 293* 5/11/07 Lot 310 PA-1 6 72.0 19.2 102.5 92.3 ND L 293A 5/11/07 Lot 310 PA-16 72.0 20.0 11 100.6 90.6 ND L 294 5/11/07 Lot 175 PA-16 75.0 j 18.7 1 99.9 90.0 ND L Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 2009 Fite: C:\excei\tables\5300\5353bi.ror.pal6 Page 1 GeoSoils, Inc. Table •1 FIELD DENSITY TEST RESULTS TEST NO DATE . TEST LOCATION . TRACT NO ELEV O MOISTURE CONTENT DEPTH (ft). DRY . DENSITY REL COMP TEST METHOD SOIL TYPE 295 5/11/07 Lot 179 PA-16 75.0 13.9 109.5 90.9 ND C 296 5/11/07 Lot 173 PA-16 78.0 14.0 108.7 90.2 ND C 297 5111/07 Lot 310 PA-16 79.0 152 104.5 91.7 SC B 298 5/11/07 Lot 176 PA-16 79.0 14.7 103.3 90.6 ND B 299 5/14/07 Lot 310 PA-16 81.0 11.6 115.1 90.6 ND A 300 5/14/07 Lot 310 PA-16 81.0 13.9 110.1 91.4 ND C 301 5/14/07 Lot 177 PA-16 81.0 15.1 103.4 90.7 ND B 302 5/14/07 Lot 176 PA-16 80.0 14.0 102.6 90.0 ND B 303 5/14/07 Lot 175 PA-16 80.0 13.7 104.0 91.2 SC B 304 5/14/07 Lot 174 PA-iS 81.0. 15.0 103.9 91.0 ND B 305 5/14/07 Lot 173 PA-16 81.0 10.0 115.2 90.7 ND A 306 5/14/07 Lot 178 PA-16 84.0 13.7 108.8 90.3 ND C 307 5/14/07 Lot 176 PA-16 84.0 13.0 108.9 90.4 SC C 308 5/14/07 Lot 174 PA-16 84.0 14.2 109.8 91.1 ND C 309 5/14/07 Lot 179 PA-16 88.0 13.6 103.2 90.5 ND B 310 5/14/07 Lot 177 PA-16 87.0 14.3 103.3 90.6 ND B 311 5/14/07 Lot 175 PA-16 86.5 10.8 116.1 91.4 ND A 312 5/14/07 Lot 173 PA-16 86.0 14.7 103.9 91.0 ND B 313 5/14/07 Lot 179 PA-16 90.0 13.7 103.3 90.6 SC B 314 5/14/07 Lot 178 PA-16 90.0 13.0 103.7 91.0 ND B 315 5/14/07 Lot 177 PA-16 90.0 14.2 102.9 90.3 ND B 316 5/14/07 Lot 179 PA-16 93.0 13.1 108.9 90.4 ND C 317 5/14/07 Lot 178 PA-16 93.0 13.6 109.5 90.9 ND C 318 5/14/07 Lot 179 PA-16 95.0 14.1 103.0 90.4 SC B 319 5/15/07 Lot 127 PA-16 78.0 13.8 109.2 90.6 ND C 320 5/15/07 Lot 126 PA-16 74.0 14.2 108.6 90.1 ND C 321 5/15/07 Lot 125 PA-16 74.0 13.6 104.2 91.4 ND B 322 5/15/07 Lot 127 PA-16 82.0 13.7 102.9 90.3 ND B 323 5/15/07 Lot 126 PA-16 77.0 14.2 103.2 90.7 ND B 324 5/15/07 Lot 125 PA-16 775 15.7 108.7 90.2 ND C 348 5/17/07 G Street PA-16 74.0 18.5 100.0 90.1 ND L 349 5/17/07 G Street PA-16 76.0 14.2 105.2 92.3 ND B 353* 5/17/07 G Street PA-16 77.0 6.8. 108.5 85.4 ND A 353A 5/18/07 GStreet PA-16 77.0 11.1 114.6 90.2 ND A 354* 5/17/07 G Street PA-16 79.0 7.9 110.6 87.1 ND A 354A 5/18/07 G Street PA-16 79.0 10.8 115.2 90.7 ND A 355 5/17/07 Lot 124 PA-16 78.0 13.7 109.4 90.8 ND C 356 5/17/07 Lot 124 PA-16 78.0 14.2 109.9 91.2 ND C 357 5/17/07 Lot 128 PA-16 81.0 13.1 103.4 90.7 ND B 358 5/17/07 Lot 127 PA-iS 83.0 14.9 109.5 90.9 ND C 359 5/17/07 Lot 126 PA-16 84.0 15.2 110.0 91.3 ND C 360 5/17/07 Lot 124 PA-16 86.0 14.7 109.1 90.5 ND C 473-FG 6/6/07 Lot 250 PA-18 74.0 17.2 103.3 90.6 ND B 546 6/13/07 Lot 167 PA-16 99.0 10.5 121.9 95.9 ND A Brook-field San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 2009 File: C:\excel\lables\5300\5353b1.ror.pals Page 2 GeoSoils, Inc. Table 1 FIELD DENSITY TEST RESULTS TEST NO. DATE . TEST LOCATION. . . •. - TRACT NO ELEV. . OR DEPTH (ft) MOISTURE CONTENT (% DRY DENSITY W-1) REL COMP TEST METHOD SOIL TYPE 547 6/13/07 Lot 164 PA-16 101.0 10.2 122.2 96.2 ND A 548 6/13/07 Lot 166 PA-16 103.0 10.7 121.7 95.8 ND A 549 6/13/07 Lot 167 PA-16 101.0 11.4 121.0 95.2 ND A 550 6/13/07 Lot 165 PA-1 6 105.0 11.8 120.7 95.0 SC A 551 6/13/07 Lot 56 PA-16 112.0 11.9 120.5 94.8 ND A 552 6/13/07 Lot 59 PA-16 114.0 10.9 121.5 95.6 ND A 553 6/13/07 Lot 57 PA-16 1160 10.3 122.1 96.1 ND A 554 6/13/07 Lot 131 PA-16 85.0 10.9 121.4 95.5 ND A 555 6/13/07 Lot 132 PA-16 88.0 11.2 120.9 95.1 ND A 556 6/14/07 Lot 127 PA-16 84.0 11.4 121.0 95.2 ND A 557 6/14/07 Lot 125 PA-16 86.0 10.9 121.5 95.6 ND A 558 6/14/07 Lot 123 PA-16 88.0 11.9 120.5 94.8 ND A 559 6/14/07 Lot 126 PA-16 88.0 11.2 120.9 95.1 ND A 560 6/14/07 Lot 58 PA-1 6 117.0 10.2 122.2 96.2 SC A 561 6/14/07 Lot 60 PA-16 117.0 10.3 122.1 96.1 ND A 564 6/14/07 Lot 183 PA-16 105.0 10.1 122.2 96.2 ND A 565 6/14/07 Lot 184 PA-16 107.0 10.7 121.5 95.6 ND A 569 6/15/07 Lot 46 PA-16 116.0 10.1 121.6 95.7 SC A 571 6/15/07 C Street 16+00 PA-16 100.0 10.7 120.5 94.8 ND A 572 6/15/07 Lot 93 PA-16 78.0 11.4 121.1 95.3 ND A 573 6/15/07 Lot 96 PA-16 75.0 11.0 120.8 95.1 ND A 574 6/15/07 Lot 98 PA-16 76.0 11.7 120.7 95.0 ND A 575 6/18/07 Lot 93 PA-16 73.5 14.2 103.2 90.5 ND B 576 6/18/07 Lot 95 PA-16 75.0 13.7 102.6 90.0 ND B 577 6/18/07 Lot 99 PA-16 81.0 13.0 103.5 90.8 ND B 578 6/18/07 Lot 93 PA-16 76.0 13.8 102.9 90.3 ND B 579 6/18/07 Lot 94 PA-16 78.5 14.2 103.9 91.1 SC B 580 6/18/07 Lot 96 PA-16 79.0 14.6 103.4 90.7 ND B 581 6/18/07 Lot 93 PA-16 79.0 13.9 102.8 90.2 ND B 582 6/18/07 Lot 97 PA-16 79.5 14.1 103.3 90.6 ND B 583 6/18/07 Lot 99 PA-16 83.0 13.3 108.5 90.0 ND C 584 6/18/07 Lot 98 PA-16 81.0 13.6 109.4 90.8 SC C 585 6/18/07 Lot 97 PA-lB 82.0 13.4 108.8 90.3 ND C 586 6/18/07 Lot 96 PA-1 6 81.0 13.7 109.6 91.0 ND C 587 6/18/07 Lot 118 PA-16 90.0 14.8 109.3 90.7 ND C 588 6/18/07 Lot 117 PA-16 88.0 14.2 108.8 90.3 ND C 601 6/18/07 Lot 117 PA-16 90.0 13.5 103.3 90.6 SC B 602 6/18/07 Lot 118 PA-16 91.5 14.1 103.0 90.3 ND B 603 6/18/07 Lot 99 PA-16 84.5 13.7 104.0 91.4 ND B 604 6/18/07 Lot 97 PA-1 6 83.0 13.0 103.5 90.8 ND B 605 6/18/07 Lot 95 PA-16 87.9 13.8 109.8 91.1 ND C 606 6/18/07 Lot 95 PA-16 81.0 14.1 108.7 90.2 SC C 607 6/18/07 Lot 93 PA-16 78.0 13.3 103.6 90.9 ND B 608 6/18/07 Lot 98 PA-16 83.0 13.9 104.1 91.3 ND B Brookfield San Diego Builders, Inc. W.O. 5353-61-SC PA 16 Robertson Ranch, East Village February 2009 File: C:\excel\tables\5300\5353b1 .ror.pal 6 Page 3 GeoSoils, Inc. Table 1 FIELD DENSITY TEST RESULTS EST: NO :;.pTE:. :.TEs-J LOCATION. : TRACT NO ELEV . OR DEPTH (ft) MOISTURE CONTENT (%) DRV.• DENSITY (pcf) ..REL.: COMP (%) TST. METHOD SOIL TYPE 633 6/20/07 Lot 55 PA-16 116.3 14.3 113.5 94.1 ND C 634 6/20/07 Lot 56 PA-16 117.3 14.0 113.8 94.4 ND C 635 6/20/07 Lot 57 PA-16 118.5 13.7 114.1 94.6 ND C 636 6/20/07 Lot 58 PA-16 119.1 13.2 114.9 95.3 ND C 637 6/20/07 Lot 59 PA-16 119.1 13.9 114.0 94.6 SC C 638 6/20/07 Lot 60 PA-16 119.0 14.7 113.1 93.8 ND C 639 6/20/07 Lot 61 PA-16 118.5 14.5 113.4 94.1 ND C 640 6/20/07 Lot 62 PA-16 118.0 14.0 113.9 94.5 ND C 641 6/20/07 Lot 63 PA-16 117.5 13.5 114.7 95.1 SC C 673-FG 6/22/07 Lot 183 PA-16 107.8 14.1 115.5 95.8 ND C 674-FG 6/22/07 Lot 184 PA-16 109.0 13.8 115.8 96.0 ND C 675-FG 6/22/07 Lot 185 PA-16 109.7 14.3 115.2 95.6 ND C 676-FG 6/22/07 Lot 186 PA-16 109.7 13.9 115.7 96.0 SC C 677-FG 6/22/07 Lot 187 PA-16 108.8 13.5 116.1 96.3 ND C 678-FG 6/22/07 Lot 188 PA-16 107.9 13.7 116.5 96.7 ND C 679-FG 6/22/07 Lot 189 PA-16 107.3 13.3 117.0 97.0 ND C 680-DF 6/22/07 Lot 310 PA-16 70.0 13.1 117.2 97.2 ND C 681-FG 6/22/07 Lot 310 PA-16 80.0 13.4 116.9 97.0 ND C 687 6/25/07 Back Slope, Lot 180 PA-16 103.0 13.4 116.0 96.2 ND C 688 6/25/07 Back Slope, Lot 181 PA-16 111.0 13.2 116.2 96.4 ND C 689 6/25/07 Back Slope, Lot 182 PA-16 112.0 13.9 115.4 95.7 ND C 690 6/25/07 Back Slope, Lot 183 PA-16 110.0 14.2 115.1 95.5 ND C 691 6/25/07 Back Slope, Lot 184 PA-16 114.0 14.7 114.5 95.0 SC C 692 6/25/07 Back Slope, Lot 185 PA-16 115.0 14.9 114.0 94.6 ND C 693 6/25/07 Back Slope, Lot 186 PA-16 115.0 13.8 115.4 95.7 ND C 694 6/25/07 Back Slope, Lot 187 PA-16 116.0 13.1 116.2 96.4 ND C 695 6/25/07 Back Slope, Lot 188 PA-16 114.0 13.7 115.7 96.0 SC C 696 6/25/07 Back Slope, Lot 189 PA-16 113.0 14.0 115.3 95.6 ND C 704 6/27/07 Lot 160 PA-16 106.9 1 11.3 119.4 94.0 ND A 705 6/27/07 Lot 161 PA-16 107.7 11.5 119.1 93.7 ND A 706 6/27/07 Lot 162 PA-16 108.5 10.9 119.8 94.3 ND A 707 6/27/07 Lot 163 PA-16 109.2 12.1 111.0 92.8 SC 0 708 6/27/07 Lot 164 PA-16 109.3 11.7 111.4 93.2 ND 0 709 6/27/07 Lot 165 PA-16 108.7 11.5 111.8. 93.5 ND 0 710 6/27/07 Lot 166 PA-1 6 106.7 11.2 119.5 94.0 SC A 711 6/27/07 Lot 167 PA-16 104.5 10.5 120.2 94.6 ND A 712 6/27/07 Lot 168 PA-16 102.5 11.4 119.3 93.9 ND A- 718 6/28/07 Lot 169 PA-16 100.0 12.3 110.8 92.7 ND 0 719 6/28/07 Lot 170 PA-16 98.0 11.5 111.8 93.5 ND 0 720 6/28/07 Lot 171 PA-16 96.0 13.1 116.8 94.9 ND M 721 6/28/07 Lot 172 PA-16 94.0 12.7 117.2 95.2 ND M 722 6/28/07 Lot 176 PA-16 91.0 11.2 122.0 96.0 ND A 723 6/28/07 Lot 177 PA-16 92.0 10.7 122.5 96.4 ND A 724 6/28/07 Lot 178 PA-16 94.0 11.1 121.9 95.9 SC A Brookfield San Diego Builders, Inc. W.O. 5353-B1-SC PA 16 Robertson Ranch, East Village February 2009 File: C:\excel\tables\5300\5353bi-ror.pal6 Page 4 GeoSoils, Inc. Table 1 FIELD DENSITY TEST RESULTS TEST NO DATE TEST LOCATION TRACT. NO : Ev.:.. OR MOISTURE CONTENT DRY . DENSITY REL. COMP (%) .TEST•. METHOD SOIL TYPE 725 6/28/07 Lot 179 PA-16 97.0 10.5 122.8 96.6 ND A 816 7/18/07 Lot 50 PA-16 117.0 14.1 112.0 92.9 ND C 817 7/18/07 Lot 49 PA-16 118.0 13.7 112.4 93.2 ND C 818 7/18/07 Lot 48 PA-16 119.0 13.2 112.9 936 ND C 819 7/18/07 Lot 47 PA-16 119.0 12.0 109.8 91.9 ND 0 820 7/18/07 Lot 46 PA-16 118.0 12.4 109.4 91.5 ND 0 821 7/18/07 . Lot 45 PA-1 6 117.0 11.6 110.3 92.3 ND 0 830 7/18/07 Glen Ave. Choker S. Side Lot 89 PA-16 71.0 12.1 118.5 94.0 ND E 831 7/18/07 Glen Ave. Choker S. Side Lot 91 PA-16 71.0 12.5 118.1 93.7 ND E 832 7/19/07 Glen Ave. Choker S. Side Lot 93 PA-16 73.0 11.9 118.9 94.3 ND E 834 7/19/07 Glen Ave, Choker S. Side Lot 92 PA-1 6 74.0 12.5 118.1 937 ND E 850 7/24/07 Wind Trail Way, Choker 18+00 PA-16 83.0 13.4 114.0 92.6 ND M 851 7/24/07 Wind Trail Way, Choker 18+40 PA-16 85.0 128 114.7 93.2 ND M 852 7/24/07 Glen Ave, Choker 12+00 PA-16 76.0 12.5 115.1 93.5 ND M 854 7/24/07 Glen Ave, Choker 11+30 PA-16 80.0 13.6 113.8 92.5 ND M 855 7/24/07 Buck Ridge Ave, Choker 10±55 PA-16 112.0 12.7 114.9 93.4 ND M 856 7/24/07 Buck Ridge Ave. Choker 10+20 PA-16 113.0 12.9 114.5 93.0 ND M 871 7/26/07 Glen Ave 10+70 PA-16 72.0 11.4 119.0 94.4 ND E 872 7/26/07 Glen Ave 11+50 PA-16 74.0 11.7 1119.3 94.6 ND 873 7/26/07 Glen Ave 12+40 PA-16 76.0 12.0 118.5 94.0 ND E 895 7/30/07 Lot 140 PA-16 92.0 12.3 1118.9 94.3 SC E 896 7/30/07 Lot 139 PA-16 93.0 12.7 118.4 93.9 ND E 897 7/30/07 Lot 138 PA-16 93.0 11.9 119.4 94.7 ND E 898 7130/07 Lot 137 PA-1 6 93.0 - 11.6 113.6 90.1 ND E 899 7/30/07 Lot 136 PA-16 93.0 11.8 119.5 94.8 SC E 900 7/30/07 Lot 135 PA-16 92.0 12.0 119.3 94.6 ND E 901 7/30/07 Lot 134 PA-iS 92.0 131 115.7 91.8 ND E 902 7/30/07 Lot 133 PA-16 91.0 11.2 120.0 95.2 ND E 903 7/30/07 Lot 132 PA-16 91.0 11.0 120.6 94.9 SC A 904 7/30/07 Lot 131 PA-16 90.0 10.5 121.1 95.3 ND A 905 7/30/07 Lot 130 PA-16 88.0 10.2 121.6 95.7 ND A 906 7/30/07 Lot 129 PA-16 87.0 11.0 120.5 94.8 SC A 907 7/30/07 Lot 128 PA-16 87.0 10.7 120.9 95.1 ND A 912-FG 7/31/07 Lot 182 PA-1 6 105.0 11.3 115.7 92.9 ND P 913-FG 7/31/07 Lot 181 PA-16 103.0 11.0 116.0 93.1 ND P 914-FG 7/31/07 Lot 180 PA-16 100.0 10.6 116.5 93.5 ND P 915-FG 7/31/07 Lot 51 PA-16 96.0 10.5 117.0 93.9 SC P 916-FG 7/31/07 Lot 52 PA-16 100.0 10.8 116.8 93.8 ND P 917-FG 7/31/07 Lot 53 PA-16 105.0 11.4 115.5 92.7 ND P 918-FG 7/31/07 Lot 54 PA-16 108.0 11.7 115.1 92.4 ND P 919-FG 7/31/07 Lot 125 PA-16 90.0 12.0 116.0 92.0 SC E 920-FG 7/31/07 Lot 126 PA-16 90.0 11.0 117.0 92.8 ND E 921-FG 7/31/07 Lot 127 PA-16 89.0 12.3 115.7 91.8 ND E 934-FG 8/3/07 Lot 124 PA-16 1 91.0 12.3 112.0 93.7 ND 0 Brookfield San Diego Builders, Inc. W. 0. 5353-B1 SC PA 16 Robertson Ranch, East Village February 2009 File: C:\excel\tables\5300\5353bl.ror. pal 6 Page 5 GeoSoils, Inc. Table 1 FIELD DENSITY TEST RESULTS tEsT .DATE Y:..fro.:..:..............,..;........'''.''..S:: . tESiLb.Anc'N.........rnAc1 1ELEv MOisTURE 'Ei (ft)(%) ENlT. COM TEST 'lETHob 'SOIL °PE 935-FG 8/3/07 Lot 123 PA-16 '910 11.9 112.5 94.1 ND 0 936-FG 8/3/07 Lot 122 PA-16 92.0 11.5 113.2 94.7 ND 0 937-FG 8/3/07 Lot 121 PA-16 92.0 12.7 111.4 93.2 SC 0 938-FG 8/3/07 Lot 120 PA-16 93.0 12.0 112.4 94.0 ND 0 939-FG 8/3/07 Lot 119 PA-16 93.0 11.7 113.0 94.5 ND 0 940-FG 8/3/07 Lot 118 PA-16 92.0 11.5 113.2 94.7 ND 0 941-FG 8/3/07 Lot 117 PA-16 92.0 11.9 112.5 94.1 ND 0 969-FG 8/10/07 Lot 99 PA-16 85.0 11.9 112.1 93.8 ND 0 970-FG 8/10/07 Lot 98 PA-1 6 84.0 11.5 112.6 94.2 ND 0 971-FG 8/10/07 Lot 97 PA-16 84.0 12.2 111.8 93.5 ND 0 972-FG 8/10/07 Lot 96 PA-16 83.0 11-7 112.4 94.0 ND 0 973-FG 8/10/07 Lot 95 PA-1 6 83.0 11.0 118.0 92.9 ND A 974-FG 8/10/07 Lot 94 PA-16 82.0 10.5 118.6 93.3 ND A 975-FG 8/10/07 Lot 93 PA-16 81.0 10.1 119.0 93.7 ND A 976-FG 8/10/07 Lot 92 PA-1 6 80.0 13.7 110.0 91.2 ND C 977-FG 8/10/07 Lot 91 PA-16 79.0 13.2 110.6 91.7 ND C 978-FG 8/10/07 Lot 90 PA-16 78.0 13.0 111.0 92.1 ND C 979-FG 8/10/07 Lot 89 PA-16 78.0 131 110.8 91.9 ND C 1005-FG 8/16/07 Lot 173 PA-16 89.0 10.6 121.0 95.2 ND A 1006-FG 8/16/07 Lot 174 . PA-16 89.0 10.3 121.3 95.5 ND A 1007-FG 8/16/07 Lot 175 PA-16 90.0 10.7 120.9 95.1 ND A 1060 9/7/07 Lot 310 PA-16 85.0 15.6 102.9 90.3 ND B 1061 9/7/07 Lot 310 PA-16 80.0 14.7 102.7 90.1 ND B 1413-FG 10/15/08 Lot 44 PA-16 117.9 8.2 122.0 91.0 SC F LEGEND: * = Failed Test A = Retest FG = Finish Grade. ND = Nuclear Densometer Test SC = Sand Cone Test Brookfield San Diego Builders, Inc. W.O. 5353B1SC PA 16 Robertson Ranch, East Village February 2009 File: C:\excel\tables\5300\5353b1.ror.pal6 Page 6 GeoSos, Inc. TABLE 2 LOT CHARACTERISTICS PA 16 LOT -E1I.', (PER ASTM D'4829) EXPANSION pOTENTIAL(l).:. SULFATE EXPOSUBE.; PLASTICITY INDEX .(pJ)(3).;? APPROX DEPTH OF FILL (RANGEIN.FI-) FOUNDATION TYPE ; 44 13 Very Low Negligible ~15 4-10 la or lb PT (5) 45 13 Very Low Negligible ~15 3-8 la or lb PT (5) 46 13 Very Low Negligible g15 3-4 la or lb PT (5) 47 13 Very Low Negligible g15 3-4 la or lb PT (5) 48 60 Medium Negligible 23-26 3-4 II PT 49* 60 Medium Negligible 23-26 3-4 Il PT 50* 60 Medium Negligible 23-26 3-4 II PT 51 11 Very Low Negligible g15 3-4 la or lb PT (5) 52 11 Very Low Negligible ~15 3-4 la or lb PT (5) 53 11 Very Low Negligible 15 3-4 Ia or lb PT (5) 54 11 Very Low Negligible 15 3-4 la or lb PT (5) 55 54 Medium Negligible 22-25 3-4 II PT 56 54 Medium Negligible 22-25 3-4 II PT 57 66 Medium Negligible 22-25 3-5 Il PT 58 66 Medium Negligible 22-25 3-4 Il PT 59 66 Medium Negligible 22-25 3-4 II PT 60 66 Medium Negligible 22-25 3-4 II PT 61 66 Medium Negligible 22-25 3-5 Il PT 62 66 Medium Negligible 22-25 4-8 II PT 63 66 Medium Negligible 22-25 7-13 Il PT 89 92 1-ugh Moderate 34-38 10-11 III PT 90 92 High Moderate 34-38 5-15 III PT 91 92 High Moderate 34-38 13-19 Ill PT 92 92 High Moderate 34-38 10-18 III PT 93 92 High Moderate 34-38 9-16 III PT 94 >130 Very High Moderate 50-54 7-8 IV PT 95 >130 Very High Moderate 50-54 4-5 IV PT 96 92 High Moderate 34-38 3-4 Ill PT 97 92 High Moderate 34-38 3-4 Ill PT 98 92 High Moderate 34-38 4-5 III PT 99 92 High Moderate 20-23 6-14 Ill PT 117 67 Medium Negligible 25-29 10-17 II PT 118 67 Medium Negligible 24-28 4-10 II PT GeoSoigs, Inc. Ail LOT' (PER ASTM , ...:D EXPANSION POTENTIAL :, -t ' SULFATE :.• EXPOSURE PLASTICITY .. INDEX PI) APPEOX DEP\TH OF FILV (RANGE .iN.FT. FOlJNDATION _______________ 119 67 Medium Negligible 24-28 3-4 II PT 120 67 Medium Negligible 24-28 3-4 II PT 121 42 Low Negligible 16-20 3-4 I PT 122 42 Low Negligible 16-20 3-4 I PT 123 42 Low Negligible 16-20 4-5 I PT 124 42 Low Negligible 16-20 7-16 I PT 125 21 Low Negligible 12-16 18-24 II PT 126 21 Low Negligible 12-16 8-24 II PT 127 21 Low Negligible 12-16 7-21 II PT 128 >130 Very High Moderate 50-54 3-6 IV PT 129 >130 Very High Moderate 50-54 3-4 IV PT 130 >130 Very High Moderate 50-54 3-5 IV PT 131 92 High Moderate 34-38 4-10 Ill PT 132 51 Medium Negligible 18-22 7-13 II PT 133 51 Medium Negligible 18-22 3-4 II PT 134 51 Medium Negligible 18-22 3-4 II PT 135 51 Medium Negligible 18-22 3-4 Il PT 136 72 Medium Negligible 26-30 3-4 II PT 138 72 Medium Negligible 26-30 3-4 II PT 139 72 Medium Negligible 26-30 3-4 II PT 140 72 Medium Negligible 26-30 3-4 II PT 160 3 Very Low Negligible ~15 3-4 la or lb P1(5) 161 3 Very Low Negligible 5 3-4 la or lb PT (5) 162 3 Very Low Negligible K15 3-4 la or lb PT (5) 163 3 Very Low Negligible g15 3-4 la or lb P1(5) 164 3 Very Low Negligible -15 3-4 la or lb PT (5) 165 63 Medium Negligible 23-27 3-4 II PT 166 63 Medium Negligible 23-27 3-4 II PT 167 63 Medium Negligible 23-27 3-4 II PT 168 63 Medium Negligible 23-27 4-5 II PT 169 63 Medium Negligible 23-27 3-4 II PT 170 55 Medium Negligible 20-24 3-4 II PT 171 55 Medium Negligible 20-24 3-4 It PT Brookfield San Diego Builders, Inc. W.O. 5353-61-SC File:e:\wp9\5300\5353b1.PA16 Table 2 Page 2 GeoSoils, Inc LOT CHARACTERISTICS PA 16 LOT...• ASTM ? D4829)* EXPANSION :; POTENTIAL (PER A.PE!AS11CITY SULFATE EXPSIJRE12 . INDEX (PI)P \rAPPRO)C DEPTH OF FILL :(RANGElNFT)' FOUNDATION TYPE 172 55 Medium Negligible 20-24 3-4 II PT 173 4-8 Low Negligible 20-24 16-32 III PT 174 48 Low Negligible 20-24 10-28 II PT 175 48 Low Negligible 20-24 8-21 II PT 176 48 Low Negligible 20-24 6-21 II PT 177 58 Medium Negligible 22-26 9-27 II PT 178 58 Medium Negligible 22-26 8-24 II PT 179 58 Medium Negligible 22-26 9-27 Il PT 180 40 Low Negligible 15-19 3-4 I PT 181 40 Low Negligible 15-19 3-4 I PT 182 40 Low Negligible 15-19 3-5 I PT 183 40 Low Negligible 15-19 3-5 I PT 184 40 Low Negligible 15-19 3-5 I PT 185 21 Low Negligible S15 3-5 I PT 186 21 Low Negligible g15 3-4 I PT 187 21 Low Negligible :515 3-4 I PT 188 21 Low Negligible :515 3-4 I PT 189 21 Low Negligible -15 3-4 I PT 307** Medium - - - 308k* Medium - - - Per ASTM 4829. Per ACI 318-08, Tables 4.2.1 and 4.3.1 (CBC, 2007). Moderate sulfate exposure requires the use of Type II cement. The higher value in the range provided, should be used for design purposes. Per GSI (2007b) and this report. Category la uses the spanability method for very low expansive soils per GSI (2008). * Lots 49 and 50 are undercut to an approximate depth of 3 to 4 feet below pad grade. Foundation design to be based on future fill soils placed within each building pad. Values shown are for estimating only. ** Recreation Area - Foundation design to be lot specific based on proposed use; will be provided upon review of site development. Brookfield San Diego Builders, Inc W.O. 5353-B1-SC File:e:\wp9\5300\5353b1 PAl 6 Table 2 Page 3 GeoSoiis, Inc. REFERENCES American Concrete Institute, 2008, Building code requirement for structural concrete (ACI 318-08) and commentary, an ACt standard reported by ACI Committee 318 dated January. 2004, Guide for concrete floor and slab construction: reported by ACI Committee' 302; Designation ACI 3021 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,,lnc., 2008a, Geotechnical plan review, model Lots 96,97, and 98, planning area 16 of Robertson Ranch, East Village, City of Carlsbad, San Diego County, California, W.0 5353-B1-SC, dated December 22. 2008b, Geotechnical update of seismic design criteria for Robertson Ranch, East Village, City of Carlsbad, San Diego County, California, W.O. 5353-B-SC, dated March 17. 2007a, Compaction report of geotechnicál observation-and testing services, 847inch 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, W0. 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. GeoSoH Inc. 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. 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 19. 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. 3459-132-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-Al-SC, dated January 29. 2001a, 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. O'Day Consultants, 2008, Grading plans for Robertson Ranch PA 16, 17, 18, Sheets 1,0 and 13, Job no. 01-1014, Carlsbad Tract C.T. 004-26, Drawing no.453-8A, dated August- Project Design Consultants, 2008, Survey Of as-built toe drains, Robertson Ranch, Job No. 3481. Romanoff, M., 1989, Underground corrosion, National Bureau of Standards Circular 579, Published by National Association of Corrosion Engineers, Houston, Texas, originally issued April 1, 1957. State of California, Department of Transportation, 2006, Highway design manual of instructions, sixth edition, September printing. Brookfield San Diego Builders, Inc- Appendix File: eAwp9\5300\5353 b l .ror.pal6 Page 2 GeSoils, Inc. LEGEND 0-047 17 At I .. 00J ot m, !EEE... - ITL_ Ai '1 -- — .----- /' J 6 Awl -/ MN Ot ' 6 J ' T •-' I RjY..— - - I j-/2N' ,,,, XRO ' ,5\X047 \0 _O x \At '°° __- / ,t .--- 5 / / , / '•,2 - - -- ,, E IA € - -'-.-- : "• 'o AS-GRADED GEOTECHNICAL MAP PAlO psi. ig 2 FRCArMrHf CONTROL SOP A5L( 5ff SHEET No. ij mm GOALS p-la 1TYOFCARlSBAD1I AST CHMA ZtRrsav RANCH jJ = RNOM 47 IiI C7l. QlT11 XME\: x-, -NOTA PART l-/--w_'.- •'-----I-----I '1- - - - .-- - .-- - 1/7 7'• * I •- .- -.- - - --- -A / 7' / / I' - -_. -A '-l-A_• •A_- - .- A I' / - -- - I / - - _•A i-A ------ ••X A -W A At -W -A -TT74.'-7 NOTAPART - --r A \- 4 / A 'f, t NOT A PARf - - - ALL LOCAIGEG ME .WAOOAXTh ] 'AS BUILT* MA ------------ AS-GRADED GEOTECHNICAL MAP PAlO PEt*22 W.O AGE-El-GE DAlE CAGE WALE r-c CIV lL_;GIETSON RANCH PAALAZ.&I8 1 •.