Loading...
HomeMy WebLinkAboutCT 01-05; CALAVERA HILLS VILLAGE W; REPORT OF ROUGH GRADING; 2004-05-12S , I :-~ ~ . '. ~ . ~ . ,,, ~ : ~ . , . ~ .. " . .1 - .. . "~ - . ,~ ., ~ .. , ~ - ;, ~ I I - i , I O I . - . .. . I I "., , ~ . I I : I I .. .,... '.:REpoRToF'RoUcHGRADING' ,.• CALAVERA HILLS, VILLAGER, BUILDING LOTS 1 THROUGH 4 DRAWING N'O 412-31.A CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA FOR 4 ( II 9AL1.AVERA HILLS II, LLC 2727 HOOVER AVENUE NATIONAL CITY, CALIFORNIA 91950 O3459i-SC MAY2, 2004 3, Geotechnical • Geologic • Environmental, 5741 Palmer Way • Carlsbad California 92008 • (760) 438-3155 • FAX (760) 931-0915 1 May 12, 2004 W.O. 3459-1-SC Calavera Hills II, LLC 2727 Hoover Avenue National City, California 91950 . . . Attention Mr. Don Mitchell Subject: Report of Rough Grading, Calavera Hills, Village A, Building Lots 1 through 4, Carlsbad Tfa0'iQj21 Drawing No. 412-3A, Carlsbad, San Diego County, California Dear Mr. Mitchell This report presents a summary of the geotechnical testing and observation services provided by GeoSoils, Inc..(GSI), during the rough earthwork construction phase of development at the subject site. Earthwork commenced in February 2004, and was g'enerally completed in March 2004. This report does not include utility and pavement constructioh testing and observations. A report of observation and testing services for - such-work will be provided under separate 'cover, when requested. •. PURPOSE OF EARTHWORK The purpose of grading was to prepare relatively level pads for the construction of four residential structures'.,Cut-and-fill grading techniques were utilized to attain the desired graded configurations. 'Cut lots and the cut portion, of transition lots were overexcavated in order to provide for more uniform foundation support. Existing topsoils and colluvium were removed to suitable bedrock material and recompacted. The grading plan for this portion of Calavera Hills II, Village A, prepared by O'Day Consultants, print dated October 22, 2003, is included with this report as Plate 1 . : . EARTH MATERIALS Subsurface geologic conditions exposed during the process of rough grading were observed by a representative of GSI. Native earth materials onsite generally consist of dense granitic/metavolcanic rock with a thin, discontinuous surficial veneer of topsoil/colluvium. Dense surficial outcrops of granitic/volcanic bedrock were noted throughout the adjoining areas. Existing compacted fill was also encountered locally. GROUNDWATER Naturally occurring groundwater was not encountered during rough grading of the building pads and should not affect the proposed building construction, provided that the recommendations contained in this report and/or provided by GSl are incorporated into final design and construction, and that prudent surface and subsurface drainage practices are incorporated into the construction plans. Based on the fractured and dense nature of the granitic/metavolcanic bedrock, perched groundwater conditions may develop in the future due to excess irrigation, homeowner altered drainage, or damaged utilities, and should be anticipated. Should manifestations of perched conditions (i.e., seepage) develop in the future, this office could assess the conditions and provide mitigative recommendations as necessary. A discussion of subdrainage is presented in a later section of this report. EARTHWORK CONSTRUCTION Earthwork operations have been completed in general accordance with the City of Carlsbad grading ordinance, and the guidelines provided in the field by this office. Observations during grading included removals, overexcavation, and subdrain construction along with general grading procedures and placement of compacted fills by the contractor. 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 existing fills) were removed to expose competent bedrock in all areas to receive fill. Calavéra Hills II, LLC W.O. 3459-B 1 -Sc Calavera Hills II, village R May 12, 2004 File: e:\wp9\3400\3459b1.r.ror Page 2 GeoSoils, Inc. In order to provide for more uniform support of structures, the cut portion of transition lots were overexcavated to a minimum depth of 3 feet below pad grade, then brought to grade with compacted fill. Cut lots exposing formational earth material were overexcavated a minimum of 3 feet below pad grade in order to facilitate foundation and utility construction. Generally, an attempt was made to slope the overexcavated bottom toward the street area. Thus, subdrainage of these areas does not appear warranted at this time, based on the available data, and lack of suitable cover (i.e.,.more than about 10 feet of fill). Subsequent to completing removals, areas to receivecompacted fill were scarified to a minimum depth of 12 inches, moisture conditioned to at least optimum moisture content, and then compacted to attain a minimum relative dompactionof 90 percent. These areas were then brought to grade with fill compacted to a minimum 90 percent relative compaction. All processing of original ground in areas to receive fill, shown on Plate 1; was. observed by a representative of GSI. Fill Placement Fill consisted of on and import materials which were placed in thin lifts, approximately , 4 to 8 inches in thickness, brought to at least optimum moisture content, and compacted to attain a minimum 90 percent relative compaction. Compaction test results on fills are presented in the attached Table 1. Approximate as-built fill thicknesses are presented in the attached Table 2. The preparation of some of these materials included processing of shot rock and oversize rock through a rock crusher. This process generally produced "6-inch minus" (in one direction) material, in general accordance with guidelines presented in GSI (2002). Fill materials generated onsite, or within the larger Calavera Hills development, from either raw excavation or produced at the crusher site, have been placed in general accordance with recommendations presented in GSI (2002). An additional criteria, developed for this project during grading, has included gradation testing (in general accordance with ASTM D-422) of stockpiled materials produced from the rock crusher. This testing has been performed in order to evaluate the percentage of "fines" included in the stockpile material. For this project, "fines" are considered to be earth materials that are 3/4 of an inch in diameter, or finer. Suitable soil fills are Oonsidered to consist of earth materials with at least ±40 percent finer than 3/4 of an inch (GSI, 2003b and 2003c). Based on our testing, a suitable material gradation was produced and utilized onsite. Calavera Hills II, LLC W. 0. 3459-B 1 -Sc Calavera Hills II, Village R May 12, 2004 File: e:\wp9\3400\3459b1.r.ror Page 3 GeoSoils, Inc. Canyon Subdrains Based on the absence of subsurface water during grading, and the configuration of site grading; including the relatively shallow fill depths within each, lot, subdrainswere not constructed. Slopes Graded Slopes In general, graded slopes constructed under the purview of this report should perform satisfactorily with respect to gross and surficial stability, provided that these slopes are properly maintained, and are subject to the prevailing semi-arid climatic conditions. Fill slopes constructed under the purview of this report were provided with a keyway excavated into suitable bedrock material in general accordance with GSI recommendations. Cut slopes were not constructed during this phase of grading. Temporary Slopes Temporary construction slopes may generally be constructed at a gradient of 1:1(horizontal:vertical [h:v]), or flatter, in compacted fill, and 1/2:1 (h:v) in suitable bedrock material (provided adverse geologic structures are not present, as evaluated by GSI prior to workers entering trenches). Utility trenches may be excavated in accordance with guidelines presented in Title 8 of the California Code of Regulations for Excavation, Trenches and Earthwork with respect to Type B soil (compacted fill) and stable rock (bedrock). Construction materials and/or stockpiled soil should not be stored within 5 feet from the top of any temporary slope. Temporary/permanent provisions shall be made to direct any potential runoff away from the top of temporary slopes. Natural Slopes Natural slopes should generally perform satisfactorily with respect to gross and surficial stability, provided they are subject to the prevailing semi-arid climatic conditions. An analysis of natural slope stability has been completed under separate cover (GSI, 1998c'). Field Testing Field density tests were performed using the sand cone method (ASTM D-1 556) and nuclear densometer method (ASTM D-2922). Tests taken for the entire Calavera Hills project were taken in consecutive numerical order. Only the test results for Village R are presented in Table 1, at the end of this report. The approximate locations of field density tests are shown on the Field Density Test Location Map, Plate 1, which utilize the 20-scale grading plans (sheet 2), prepared by O'Day Consultants, Inc., as a base map; .• Calavera Hills II, LLC . W.O. 3459-131-SC Calavera Hills II, Village A . May 12, 2004 File: e:\wp9\3400\3459b1.r.ror Page 4 GeoSoils, Inc. Field density tests were taken at periodic intervals and random locations to check the compactive effort provided by the contractor. Based on the operations observed, test results presented herein are 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 for a given density test. Rocky soil fills were periodically inspected using dozer pits in order to verify adequate moisture content and relative compaction. Testing and observations were performed on a full-time basis. LABORATORY TESTING Moisture-Density Relations The laboratory maximum dry density and optimum moisture content for each major soil type was determined according to Test Method ASTM D-1 557. The following table presents the test results: - .. . 'MAXIMUM DRY OPTIMUM MOISTURE - soiL 1PE . . -. OENIf(pc. ...CONTENT J - Brown, Silty SAND w/Gravel (processed material) 134.0 8.0 Q - Yellowish Brown, Silty SAND w/Gravel (import) 119.0 14.0 Expansive Soils Expansive soil conditions have been evaluated for the site. Representative samples of soil near pad grade were recovered for classification and expansion testing. Expansion Index (E.l.) testing was performed in general accordance with Standard 18-2 of the Uniform Building Code ([UBC], International Conference of Building Officials [lCBO], 1997). Representative expansion indices indicate that site soils near pad grade, within the subject lots, are very low expansive (E.l. <20). A summary of soil expansion results are presented in the attached Table 2. Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 Fi1e:e:\wp9\3400\3459b1 .r.ror Page 5 GeoSoils, Inc. Corrosion/Sulfate Testing Typical samples of the site materials were analyzed for corrosion/soluble sulfate potential. Soil sulfate testing indicates that the sulfate exposure to concrete is negligible, in accordance with Table 19-A of the UBC (ICBO, 1997). Site soils are considered corrosive to ferrous, materials when wet or saturated. While it is our understanding that standard concrete cover is sufficient mitigation, alternative methods and additional comments should be obtained from a qualified corrosion engineer. Sieve Analysis Sample gradation for various representative samples was determined in general accordance with ASTM Test Method D-422. Test results generally indicated that at least 40 percent of each sample-was finer than. the 3/4 inch sieve in accordance with GSl (2003b and 2003c). RECOMMENDATIONS -FOUNDATIONS General The foundation designand construction recommendations are based on laboratory testing and engineering analysis of onsite earth materials by GSl. Minimum recommendations for conventional or post-tension (PT) 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. The proposed foundation systems shall be designed and constructed in accordance with the guidelines contained in the UBC. All footing designs shall be reviewed and approved by the project structural engineer/foundation designer. Based on soil expansion potential and the as-built fill thicknesses (i.e., differential fill thickness exceeding 3:1, maximum to minimum, across the lot), conventional or PT foundations may be. constructed. - Conventional Foundation Design Conventional spread and continuous footings may be used to support the proposed residential structures provided they are founded entirely in properly compacted fill or other competent bearing material (i.e., bedrock). . Footings shall not simultaneously bear directly on bedrock and fill soils. 2. Analyses indicate that an allowable bearing value of 2,000 pounds per square foot (psf) may be used for design of continuous footings per Table 3, and for design of isolated pad footings 24 inches square and 18 inches deep into properly compacted fill or bedrock. The bearing value may be increased by one-third for seismic or other temporary loads. This value may be increased by 20 percent for Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village A . May 12, 2004 Fiie:e:\wp9\3400\3459b1.r.ror . Page 6 GeoSoils, Inc. each additional 12 inches in depth, to a maximum of 2,500 psf. No increase, in bearing, for footing width is recommended. For lateral sliding resistance, a 0.4 coefficient of friction may be utilized for a concrete to soil contact when multiplied by the dead load. Passive earth pressure may be computed as an equivalent fluid having a density of 300 pounds per cubic foot (pcf) with a maximum earth pressure of 2,500 psf. When combining passive pressure and frictional resistance, the passive pressure component shall be reduced by one-third. Footings shall maintain a horizontal distance or setback between any adjacent slope face and the bottom outer edge of the footing. The horizontal distance may be calculated by using h/3 (where h is the height of the slope). The horizontal setback shall not be less than 7 feet, nor need not be greater than 40 feet (per code). The setback may be maintained by simply deepening the footings. Flatwork, utilities, or other improvements within a zone of h/3 from the top of slope may be subject to lateral distortion. Footings, flatwork, and utility setbacks shall be constructed in accordance with distances indicated in this section, and/or the approved plans. Provided that the recommendations contained in this report are incorporated into final design and construction phase of development, a majority (>50 percent) of the anticipated foundation settlement is expected to occur during construction. Maximum settlement is not expected to exceed approximately 11/2 inches and should occur below the heaviest loaded columns. Differential settlement is not anticipated to exceed 3/4 inch between similar elemenjs, in a40-foot span. Conventional Foundation/Concrete Slab Construction The following construction recommendations are based on generally very low to low expansive bearing soils and maximum fill thicknesses of less than approximately 30 feet. Conventional continuous, footings shall be constructed in accordance with recommendations presented.in Table 3, and in accordance with UBC (lCBO, 1997). guidelines. All footings shall be minimally reinforced per Table 3. Detached isolated interior or exterior piers and columns shall. be founded at a minimum depth of 18 inches .below the lowest adjacent ground surface and tied to the main foundation in at least one direction with a grade beam. Reinforcement shall be properly designed by the project structural engineer. Calavera Hills II, LLC ' W.O. 3459-B1-SC Calavera Hills II, Village A . . May 12, 2004 File:e:\wp9\3400\3459b1 .r.ror . ' Page 7 GeoSoils, Inc. A grade beam, reinforced as above and at least 12 inches square, shall be provided across the garage entrances. The base of the reinforced grade beam shall be at the same elevation as base of the adjoining footings. The residential floor and garage slabs shall have a minimum thickness of 4 inches, in accordance with Table 3. Concrete used in floor slab construction shall have a minimum compressive strength of 2,500 psi. Concrete slabs shall be underlain with a minimum of 4 inches of sand. In addition, a vapor barrier consisting of a minimum of 1 0-mil, polyvinyl-chloride membrane with all laps sealed, shall be provided at the mid-point of the sand layer. The slab subgrade shall be free of loose and uncompacted material prior to placing concrete. Concrete floor slabs (residence and garage) shall be reinforced per Table 3. All slab reinforcement shall be supported to ensure proper mid-slab height positioning during placement of the concrete. "Hooking" of reinforcement is not an acceptable method of positioning. Presaturation is not considered necessary for these soil conditions; however, the moisture content of the subgrade soils shall be equal to, or greater than, optimum moisture to a depth of 12 to 18 inches (depending on footing embedment) below the adjacent ground grade in the slab areas, and verified by this office within 72 hours of the vapor barrier placement. Soils generated from footing excavations to be used onsite shall be compacted to a minimum relative compaction 90 percent of the laboratory standard, whether it is to be placed inside the foundation perimeter or in the yard/right-of-way areas. This material must not alter positive drainage patterns that direct drainage away from the structural areas and toward the street. Proposed pools and other appurtenant structures should consider that excavation difficulties will likely be encountered in some lots at depths greater than approximately 3 feet below existing building pad grades due to the presence of dense granitic rock. Please refer to Table 2 for a listing of lots with relatively shallow (i.e., <10 feet) fills. As an alternative, an engineered PT foundation system may be used. Recommendations for PT slab design are presented in the following section. Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 File:e:\wp9\3400\3459b1.r.ror Page 8 GeoSoils, Inc. PT Slab Foundation Systems PT slabs may be utilized for construction of typical one- and two- story residential structures onsite. The information and recommendations presented in this section are not meant to supercede design by a registered structural engineer or civil engineer familiar with PT slab design or corrosion engineering consultant. From a soil expansion/shrinkage standpoint, a fairly common contributing factor to distress of structures using PT 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 presaturation (if necessary, or after the project has been dormant for a period of time) and construction of a perimeter "cut off' wall grade beam may be employed. For very low to low (E.l. 0 through 50) expansive soils, perimeter and mid span beams shall be a minimum 12 inches 'deep below the lowest adjacent pad grade The perimeter foundations may be integrated into, the slab design or independent of the slab. The perimeter beams shall be a minimum of 12 inches in width. A vapor barrier shall be utilized and be of sufficient thickness to provide an adequate separation of foundation from soils (10 mil thick). The vapor barrier should be adequately sealed to provide a continuous water-resistant barrier under the entire slab. The vapor barrier shall be sandwiched between two 2-inch thick layers of sand (SE>30) for a total of 4 inches of sand. Isolated piers should be incorporated into the PT slab system. Specific soil presaturation for slabs is not required for very low expansive soils; however, the moisture content of the subgrade soils shall be at or above the soils' optimum moisture content to a minimum depth of 12 to 18 inches below grade, depending on the footing embedment. PT slabs shall be designed using sound engineering practice and be in accordance with the Post-Tension Institute (PTl), local, and/or national code criteria and the recommendations of a structural or civil engineer qualified in PT slab design. Alternatives to PTI' methodology may be used if equivalent systems can be proposed which accommodate the angular distortions, expansion parameters, and settlements noted for this project. If alternatives to PTI are suggested by the designer or structural consultant, consideration should be given for additional review by a qualified structural PT designer. Soil related parameters for PT slab design, are presented on the following: Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village A , May 12, 2004 File: e:wp9\34OO\3459b1 .r.ror . . . Page 9 GeoSoils, Inc. Perimeter Footing Embedment** CATEGORY I (PT)* CATEGORY II (PT) 12 inches 12 inches** Allowable Bearing Value 1,000 pSf*** 1,000 pSf*** Modules of subgrade reaction 100 psi/inch 75 psi/inch Coefficient of Friction 0.35 0.35 Passive Pressure 225 pcf 225 pcf Soil Suction (P1) 3.6 3.6 Depth to Constant Soil Suction 5 feet 5 feet Thornthwaite Moisture -20.0 -20.0 em Edge 2.5 2.7 em Center 5.0 5.5 'm edge 0.35 0.5 y, Center 1.1 2.0 Minimum Slab Thickness 5 inches 5 inches * Foundation design using the spanability method may also be used for Category I conditions. ** Lab data indicates E.I. 0-50 for this site. Bearing for slab on grade only, bearing value for interior or perimeter beams shall be in accordance with parameters provided for conventional continuous and isolated spread footings. Provided the recommendations contained in this report are incorporated into the final design and construction phase of development, a majority (>50 percent) of the - anticipated foundation settlement is expected to occur during construction. Maximum total settlement is not expected to exceed approximately 1 1/2 inches, and should occur below the heaviest loaded columns. Differential settlement is not anticipated to exceed 3/4 of an inch between similar elements, in a 40-foot span. Designers of PT slabs shall review the parameters provided for PT slabs and compare using a span distance of 5 feet, using a modules of subgrade reaction of 125 psi in their evaluation. In accordance with guidelines presented in the U BC,. improvements and/or footings shall maintain a horizontal distance, X, between any adjacent descending slope face and the bottom outer edge of the improvement and/or footing. The horizontal distance, X, may be calculated by using X = h/3. X shall not be less than 7 feet, nor need not be greater. than 40 feet. X may be maintained by deepening the footings. Improvements constructed within a distance of h/3 from the top of slope may be subject to lateral distortion. Foundations for any adjacent structures, including retaining walls, should be deepened (as necessary) to below a 1:1 projection upward and away from any proposed lower foundation system. This recommendation may not be considered valid if the additional surcharge imparted by the upper foundation on the lower foundation has been incorporated into the design of the lower foundation. Additional setbacks, not discussed or superceded herein, and presented in the UBC are considered valid. Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 FiIe:e:\wp9\3400\3459b1 .r.ror Page 10 GeoSoils, Inc. EXTERIOR FLATWORK Exterior driveways, walkways, sidewalks, or patios, using concrete slab-on-grade construction, shall be designed and constructed in accordance with the following criteria: Driveway slabs shall be a minimum 4 inches in thickness; all other exterior slabs may be a nominal 4 inches in thickness; however, such nominal slabs will be at increased risk for distress. A thickened edge shall be considered for all flatwork adjacent to landscape areas. Slab subgrade shall be -compacted to a minimum 90 percent relative compaction and moisture conditioned to at, or above, the soils optimum moisture content. The use of transverse and longitudinal control joints shall be considered to help control slab cracking due to concrete shrinkage or expansion. Two of the best ways to control this movement are: 1) add a sufficient amount of properly placed reinforcing steel, increasing tensile strength of the slab such as 6x6, Wi .4xWl .4; and/or, 2) provide an adequate amount of control and/or expansion joints to accommodate anticipated concrete shrinkage and expansion. We would suggest that the maximum control joint spacing be placed on 5- to 8-foot centers, or the smallest dimension of the slab, whichever is least. No traffic should be allowed upon the newly poured concrete slabs until they have been properly cured to within 75 percent of design strength. - Positive site drainage should be maintained at all times. Adjacent landscaping shall be graded to drain into the street/parking area, or other approved area. All surface water shall be appropriately directed to areas designed for site drainage. Concrete compression strength shall be a minimum of 2,500 psi. WALL DESIGN PARAMETERS Conventional Retaining Walls The design parameters provided.below assume that either hon expansive soils (Class 2 permeable, filter material or Class 3 aggregate base) ar native, materials (up to and including an Expansion Index [E.I.] of 65) 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 or damp-proofed, depending on the degree of moisture protection desired. 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, as appropriate. Calavera Hills II, LLC . W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 Fi1e:e:\wp9\3400\3459b1.r.ror . Page 11 GeoSolis, Inc. 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. 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 65 pounds per cubic foot (pcf), plus any applicable surcharge loading. For areas of male or re-entrant corners, the restrained wall design should extend a minimum distance of twice the height of the wall (2H) laterally from the corner. Cantilevered Walls The recommendations presented below are for cantilevered retaining walls up to 10 feet high. Design parameters for. walls less than 3 feet in height may be superseded 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. SURFACE SLOPE OF EQUIVALENT EQUIVALENT RETAINED MATERIAL FLUID WEIGHT P C F FLUID WEIGHT P C F (HORiZONTAL:VERTIcAL. (SELECT BACKFILL•.. . (NATIVE BACKFILL): Level* 35 1 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. RetainingWall Backfill and Drainage Positive drainage must be provided behind all retaining walls in the form of gravel wrapped in geofabric and outlets. A backd rain system is considered necessary for retaining walls that are 2 feet or greater in height. Details 1, 2, and 3, present the back drainage options discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS Calavera Hills II, LLC W.O459-B1-Sc Calavera Hills II, Village A May 12, 2004 File:e:\wp9\3400\3459b1 s.ror Page 12 GeoSoils, Inc. Provide Waterproofing Membrane (option © Weep Hc Finished SUrfaCE DETAILS N.T.S.: WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. © ROCK: 3/4 to 1-1/2" (inches) rock. - © FILTER FABRIC: Mirafi 140N or approved equivalent; place fabric flap behind core. PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1% gradient to proper outlet point. © WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) - TYPICAL RETAINING WALL BACKFILL S . •) ( - AND DRAINAGE DETAIL eooils, InC. DETAIL 1 -. . - Geotechnical • Geologic • Environmental Provide (!)Waterproofing Membrane (a © Weep Finished DETAILS N I S . WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. DRAIN: Miradrain 6000 or 3-drain 200 or equivalent for non-waterproofed walls. Miradrain 6200 or 3-drain 200 or equivalent for waterproofed walls. © FILTER FABRIC: Mirafi 140N or approved equivalent; place fabric flap behind care. PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1% gradient to proper outlet point. © WEEP HOLE: - Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) RETAINING WALL BACKFILL AND SUBDRAIN DETAIL eoi1s,Inc. GEOTEXTILE DRAIN L2 Geotechnical • Geologic • Environmental fllTAll C N.T.S. 2 Native Backfill Provide Surface Drainage Slope or Level J min 0 .:. . Waterproofing 1 Membrane (optional) 1 or Flatter Q clean H ® Weep Hole © Filter Fabric Roc : !nkfill Finished Surface Pipe Heel Width 4 @ WATERPROOFING MEMBRANE (optional): Liquid boot or approved equivalent. CLEAN SAND BACKFILL: Must have sand dequivalent value of 30 or greater; can be densified by water jetting. © FILTER FABRIC: Mirafi 140N or approved equivalent. ROCK: 1 cubic foot per linear feet of pipe or 3/4 to 1-1/2" (inches) rock.' PIPE: 4" (inches) diameter perforated PVC. schedule 40 or approved alternative with minimum of 1% gradient to proper outlet point. WEEP HOLE: Minimum 2" (inches) diameter placed at 20' (feet) on centers along the wall, and 3" (inches) above finished surface. (No weep holes for basement walls.) RETAINING WALL AND SUBDRAIN DETAIL 7fl - CLEAN SAND BACKFILL DETAIL 3 Geotechnical • Geologic • Environmental. L pipe encased in either Class 2 permeable filter material or ½-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 should be used behind the wall. This material should be continuous (i.e., full height) behind the wall, and it should be constructed in accordance with the enclosed Detail 1 (Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined areas, (panel) drainage behind the Wall may be constructed in accordance with Detail 2 (Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an E.I. potential of greater than 65 should not be used as backfill for retaining walls. For more onerous expansive situations, backfill and drainage behind the retaining wall should conform with 'Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill). 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 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. 1. .. 90). Proper surface drainage should also be provided. For additional mitigation, consideration should be given to applying a water-proof membrane to the back of all retaining structures. The use of. a waterstop should be considered for all concrete and masonry joints. 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 1/360 for a distance of 2H on either side of the transition may be accommodated. Expansion joints should be sealed with a flexible, 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. Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 File: e:\wp9\3400\3459b1.r.ror ' . Page 16 GeoSoils, Inc. TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS Slope Creep Soils at the site may be expansive and therefore, may become desiccated when allowed to dry. Such soils are susceptible to surficial slope creep, especially with seasonal changes in moisture content. Typically in southern California, during the hot and dry summer period, these soils become desiccated and shrink, thereby developing surface cracks. The extent and depth of these shrinkage cracks depend on many factors such as the nature and expansivity of the soils, temperature and humidity, and extraction of moisture from surface soils by plants and roots. When seasonal rains occur, water percolates into the cracks and fissures, causing slope surfaces to expand, with a corresponding loss in soil density and shear strength near the slope surface. With the passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials experience a very slow, but progressive, outward and downward movement, known as slope creep. For slope heights greater than 10 feet, this creep related soil movement will typically impact all rear yard flatwork and other secondary improvements that are located within abOut 15 feet from the top of slopes, such as swimming pools, concrete flatwork, etc., and in particular top of slope fences/walls. This influence is normally in the form of detrimental settlement, and tilting of the proposed improvements. The dessication/swelling and creep discussed above continues over the life of the improvements, and generally becomes progressively worse. Accordingly, the developer should provide this information to any homeowners and homeowners association. Top of Slope Walls/Fences Due to the potential for slope creep 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. The grade beam' should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on center, and with a minimum embedment length of 7 feet below the bottom of the grade beam. The strength of the concrete and grout should be evaluated by the structural engineer of record. The proper ASTM tests for the concrete and mortar should be provided along with the slump quantities. The concrete used should be appropriate to mitigate sulfate corrosion, as warranted. The design of the grade beam and caissons should be in accordance with the recommendations of the project structural engineer, and include the utilization of the following geotechnical parameters: Calavera Hills II, LLC W.O. 3459-B 1 -Sc calavera Hills.Il, Village A May 12, 2004 FiIe:e:\wp9\3400\3459b1.r.ror Page 17 GeoSoils, Inc. Creep Zone: 5-foot vertical zone below the slope face and projected upward parallel to the slope face. Creep Load: The creep load projected on the area of the grade beam - should be taken as an equivalent fluid approach, having a V density of 60 pcf. For the caisson, it should be taken as a uniform 900 pounds per linear foot of caisson's depth, located above the creep zone. Point of Fixity: Located a distance of 1 .5 times the caisson's diameter, below the creep zone. Passive. Resistance: Passive earth pressure of 300 psf per foot of depth per foot of caisson diameter, to a maximum value of 4,500 psf may be V • used to determine caisson depth and spacing, provided that V they meet or exceed the minimum requirements stated above. - V To determine the total lateral resistance, the contribution of the V creep prone zone above the point of fixityi to passive V resistance, should be disregarded. V Allowable Axial Capacity: Shaft capacity: V - 350 psf applied below the point of fixity over the ,surface area of the shaft. Tip capacity: 4,500 psf. V • DRIVEWAY FLATWÔRKg AND OTHER IMPROVEMENTS The soil materials on site may be expansive. The effects of expansive soils are cumulative, V V 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 that end, it is recommended that the developer should notify any homeowners or homeowners association of this V long-term potential for distress. To reduce the likelihood of distress, the following V V recommendations are presented for all exterior flatwork: - The subgrade area-for concrete slabs should be compacted to achieve a minimum 90 percent relative compaction, and then be presoaked to 2 to 3 percentage points V above (or'125 percent of) the soils' optimum moisture content, to a depth of 18 inches below subgrade elevation. If very low expansive soils are present, only optimum moisture content,.or greater, is required and specific presoaking is not Calavera Hills II, LLC V V W.O. 3459-B1-SC Calavera Hills II, Village A V V V May 12, 2004 Fi1e:e:\wp9\3400\3459b1 .r.ror V V Page 18 GeoSoils, Inc. warranted. The moisture content of the subgrade should be verified within 72 hours prior to pouring concrete. - 2. Concrete slabs should be cast over a non-yielding surface, consisting of a 4-inch layer of crushed rock, gravel, or clean sand, that should be compacted and level prior to pouring concrete. If very low expansive soils are present, the rock or gravel or sand may be deleted. The layer or subgrade should be wet-down completely prior to pouring concrete, to minimize loss of concrete moisture to the surrounding earth materials. Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and approaches should additionally have a thickened edge (12 inches) adjacent to all landscape areas, 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, slabs should be reinforced at mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each direction. The exterior slabs should be scored or saw cut, ½ to % inches deep, often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or narrow slabs, control joints should be provided at intervals of every 6 feet. The slabs should be separated from the foundations and sidewalks with expansion 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 the house should be separated from the-house with thick expansion 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. Calavera Hills II, LLC . W.O. 3459-B1-SC Calaverá Hills II, Village A May 12, 2004 Fi1e:e:\wp9\3400\3459b1.r.ror . Page 19 GeoSoils, Inc. 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. 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 a minimum of 1 to 2 percent fall to the street, as indicated herein. It should be kept in mind that drainage reversals could occur, including post-construction settlement, if relatively flat yard drainage gradients are n 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 a rigid slab with flexible couplings for plumbing and electrical lines. NC waste water lines should be drained to a suitable non-erosive 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. 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 (LIFE). Slope Creep Slope creep is caused by alternate wetting and drying of the fill soils which results in slow downslope movement. This type of movement is expected to occur throughout the life of the slope, and is anticipated to potentially affect improvements or structures (i.e., separations and/or cracking), placed near the top-of-slope, generally within a horizontal Calavera Hills II, LLC . . . W.O. 3459-B1-SC Calavera Hills II, Village A May 12, 2004 File: e:\wp9\3400\3459 b 1.r.ror . . Page 20 GeoSoils, Inc. distance of approximately 15 feet, measured from the outer, deepest (bottom outside) edge of the improvement, to the face of slope. The actual width of the zone affected is generally dependant upon: 1) the height of the slope; 2) the amount of irrigation/rainfall the slope receives; and, 3) the type of materials comprising the slope. This movement generally results in rotation and differential settlement of improvements located within the creep zone. Suitable mitigative measures to reduce the potential for distress due to lateral deformation typically include: setback of improvements from the slope faces (per the 1997 UBC and/or California Building Code); positive structural separations (i.e., joints) between improvements; and, stiffening and deepening of foundations. Per Section 1806.5.3 of the UBC, 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 1806.5.6 of the UBC, H/3 generally need not be greater than 20 feet for the Calavera Hills II development. As an alternative to a deepened footing, where the ad jacent slope is greater than 45 feet in height and the building/footing is within 20 feet from the slope face, a differential settlement of /2 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.) shall consider the above. Proper disclosure to homeowners and/or homeowners associations is recommended. Lateral Fill Extension (LFE) LFE occurs due to deep wetting from irrigation and rainfall on slopes comprised of expansive materials. Based on the generally very low expansive character of onsite soils, the potential component of slope deformation due to LFE is considered minor, but may not be totally precluded. Although some movement should be expected, long-term movement from this source may be minimized, but not eliminated, by placing the fill throughout the slope region, wet of the fill's optimum moisture content. During grading of the site, GSI observed fill soil moisture contents during, fill placement and compaction. Our observations indicate that the moisture content. of the fill is generally above the soils optimum moisture content, in accordance with our recommendations. SUMMARY It is generally not practical to attempt to eliminate the effects of either slope creep or LFE. Suitable mitigative measures to reduce the potential of lateral deformation typically include: setback of improvements from the slope faces (per the 1997 UBC and/or California Building Code); positive structural separations (i.e., joints) between improvements; stiffening; and, deepening of foundations. All of these measures are recommended for design of structures and improvements and minimizing the placement of "dry" fills. The Calavera Hills II, LLC S W.O. 3459-B1-SC Calavera Hills II, Village R S May 12, 2004 File: e:wp9\34OO\3459b1 .r.ror Page 21 GeoSoils, Inc. ramifications of the above conditions, and recommendations for mitigation, should be provided to each homeowner and/or any homeowners association. 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, shall be maintained and only the amount of irrigation necessary to sustain plant life should be provided for planted slopes. Over-watering should be avoided as it can adversely affect site improvements and cause perched groundwater conditions. Graded slopes constructed Utilizing onsite materials would be erosive. Eroded debris may be minimized and surficial slope stability enhanced by establishing and maintaining a suitable vegetation cover soon after construction. Compaction to the face of fill slopeswould tend to minimize short-term erosion until vegetation is established. Plants selected for landscaping should be light weight, deep rooted types that require little water and are capable of surviving the prevailing climate. Jute-type matting, or other fibrous covers, may aid in allowing the establishment of a sparse plant cover. Utilizing plants other than those recommended above will increase the potential for perched water, staining, mold, etc. to develop. A rodent control program to prevent burrowing should be implemented. Irrigation of natural (ungraded) slope areas is generally not recommended. These recommendations regarding plant type, irrigation practices, and rodent control should be provided to each homeowner. 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 shall be sufficient to prevent ponding of water anywhere on a lot, and especially near structures and 1tops of slopes. Lot surface drainage shall be carefully taken into consideration during fine grading, landscaping, and building construction. Therefore, care shall be taken that future landscaping or construction activities do not create adverse drainage conditions. Positive site drainage within lots and common areas shall be provided and maintained at all times. Drainage shall 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 5 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 planters adjacent to structures (buildings, pools, spas, etc.). Pad drainage shall 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 5 feet from structures or into a subsurface drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 FUe:e:\wp9\3400\3459b1.r.ror Page 22 GeoSoils, Inc. 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 shall be given to providing hay bales and silt fences for the temporary control of surface water, from a geotechnical viewpoint. Landscape Maintenance Only the amount of irrigation necessary to sustain plant life should be provided. Over-watering the landscape areas will adversely affect proposed site improvements. We recommend that any open-bottom, raised box planters adjacent to proposed structures be restricted for a minimum distance of 10 feet. As an alternative, closed-bottom type 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 barrier to prevent penetration of irrigation water into the subgrade. Provisions should be made to drain the excess irrigation water from the planters without saturating the subgrade below or adjacent to the planters. Graded slope areas should be planted with drought resistant vegetation. Consideration should be given to the type of vegetation chosen and their potential effect upon surface improvements (i.e., some trees will have an effect on concrete flatwork with their extensive root systems). From a geotechnical standpoint, leaching is not recommended for establishing landscaping. If the surface soils are processed for the purpose of adding amendments, they should be recompacted to 90 percent minimum relative compaction. Subsurface and Surface Water Subsurface and surface water are not anticipated to affect site development, provided the recommendations contained in this report are incorporated into final design and construction, and that prudent surfaceand 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. Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 File:e:\wp9\3400\3459b1.r.ror Page 23 GeoSoils, Inc. Additional Gradin This office shall be notified in advanbe of any fill placement, supplemental regrading of the site, or trench backfilling after rough grading has been completed. This includes completion of grading in the Street and parking areas and utility trench and retaining wall backfills. S OTHER DESIGN PROFESSIONALS/CONSULTANTS The design civil engineer structural engineer, post-tension designer, architect, landscape architect, wall designer, etc. shall review the recommendations provided herein, incorporate these recommendations into all their respective plans, and by explicit reference, make this report part of their project plans. S The opportunity to be of service is sincerely appreciated. If you should have any questions, please do not hesitate to call our office. Respectfully "\ \ GeoSoils, Inc. ( 3$ c,' \ Rev wed by: 63 Olo Robert G Crisman \2,)David W. Skelly OX Engineering Geologist, Civil Engineer, RCE 4 57 RGC/JPF/DWS/jk Attachments: Table 1 - Field Density Test Results Table 2 - Lot Characteristics Table 3 - Foundation Construction Recommendations Appendix - References Plates 1 - Field Density Test Location Map Distribution: (6) Addressee (1) Jobsite, Attention: Mr. Tom LaMarca Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May 12, 2004 File: e:\wp9\3400\3459b1.r.ror Page 25 GeoSoils, Inc. S Table 1 FIELD DENSITY TEST RESULTS TEST NO. DATE TEST LOCATION VILLAGE ELEV OR DEPTH (It) MOISTURE CONTENT DRY DENSITY REL COMP TEST METHOD SOIL TYPE 2205 2/2/04 Rear Lot i Village 250.0 14.6 109.2 91.3 SC Q 2206 2/2/04 Rear Lot Village 250.0 13.9 107.8 90,2 ND Q 2207 2/2/04 Rear Lot 1 Village R 251.0 14.6 109.2 91.4 ND Q 2207 2/2/04 Rear Lot 1 Keyway Village R 249.0 14.2 108.0 90.3 ND Q 2208 2/2/04 Rear Lot Slope Area Village 254,0 14.6 108.6 90.8 ND Q 2209 2/2/04 Rear Lot Slope Area Village 253.0 14.1 109.0 91.2 ND Q 2210* 2/2/04 Rear Lot 1 Slope Area Village R 256.0 14.5 100.4 84.0 ND Q 2210A 2/2/04 Rear Lot 1 Slope Area Village R 256.0 14.0 109.6 91.7 ND Q 2211* 2/3/04 Rear Lot 2 Key Area Village 251.0 19.4 100.1 83.7 ND 0 2211A 2/3/04 Rear Lot 2 Key Area Village 251.0 14.1 108.2 90.5 ND 0 2212 2/3/04 Rear Lot 1-2 Key Area Village R 256.0 14.5 108.9 91.1 ND Q- 2213 2/3/04 Rear Lot Slope Area Village 258.0 14.2 109.1 91.2 ND 0 2228* 2/4/04 Rear Lot2 Key Area Village 257.0 14.1 101.4 84.8 ND 0 2228A 2/4/04 Rear Lot 2 Key Area Village R 257.0 14.2 108.0 90.3 ND 0 2229 2/4/04 Rear Lot Key Area Village R 268.0 14.6 108.6 90.8 SC Q 2230 2/4/04 Rear Lot 2 Slope Area Village 259.0 14.0 109.0 91.2 ND 0 2231 2/4/04 Rear Lot 3 Key Area Village R 268.0 14.1 108.1 90.4 ND 0 2232 2/4/04 Rear Lot 4 Key Area Village R 271.0 14.6 109.2 91.3 ND 0 2233 2/4/04 Rear Lot 3 Pad Area Village R 270.0 14.2 108.9 91.1 ND 0 FG-2420 3/23/04 Rear Lot 2 Village A 260.0 8.2 _11_ 90.2 ND J FG-2421 3/23/04 Rear Lot 2 Village R 262.0 8.0 _122_ 90.9 ND FG-2422 3/23/04 Rear Lot 1 Village A 264.0 8.3 121.6 90.7 ND J FG-2423 3/23/04 Rear Lot 1 Village R 258.0 8,4 122.2 91.1 ND J FG-2424 3/23/04 Rear Lot 1 Village R 260.0 8.0 123.4 92.0 ND J FG-2425 3/24/04 Center Lot Village R 264.0 8.2 1220 91.0 ND J. FG-2426 3/24/04 Center Lot 1 Village R 266.0 8.5 121.3 90.5 ND J FG-2427 3/24/04 West Lot 1 Village A 262.0 8.0 22.6 - 91.4 ND J FG-2428 3/25/04 West Lot 1 Village R 268.0 8.2 21.6 - 90.7 ND J FG-2429 3/25/04 Lots 1-2 Village R 268.0 8.9 220 - 91.0 ND J FG-2430 3/25/04 East Lot 2 Village R 270.0 9.0 21.3 - 90.5 ND J FG-2431 3/25/04 Front Lot 1 Village R 270.0 8.6 22.4 - 91.3 ND J FG-2440 3/26/04 Lot 4 Village R 272.0 8.6 . 24.0 - 92.5 ND _J - FG-2441 3/26/04 Lot 3 Village R 272.0 9.0 236 - 92.2 ND _J - FG-2442 3/29/04 Lot 1 Village R FG 8.2 _122.0 91.0 ND _J_ FG-2443 3/29/04 Lot Village R FG 8.3 121.9 90.9 ND J FG-2444 3/29/04 Lot 3 Village R FG 8.0 124.0 92.5 ND J FG-2445 3/29/04 Lot 4 Village A FG 8.6 123.0 91.7 ND 1 J LEGEND: = Indicates Repeated Test Number * = Indicates Failed Test A = Indicates Retest FG = Finish Grade ND = Nuclear Densometer SC = Sand Cone Calavera Hills II, LLC W.O. 3459-B1-SC Calavera Hills II, Village R May, 2004 File: C:\excel\tables\3400\3459b1,r,ror GeoSoils, Inc. Page 1 TABLE 2 - . ';-. . LOT CHARACTERISTICS - CAVERA HILLS, VILLAGE R :• EXPANSION!DEPTH INDEX SOLUBLE OF FILL ? . (per UBC : EXPANSION .:SULFATE SULFATE (Range FOUNDATION LOT - Standard 18-2). POTENTIAL' (Weight %) EX0O01 IRE2 in Ft.) CATEGORY 43) 1 <20 Very Low <0.10 Negligible 5-12 iorl(PT) 2 <20 Very Low <0.10 Negligible 7-13 I or l(PT) 3 -. <20 Very Low <0.10 Negligible 3-9 I or i(PT) 4 <20 Very Low <0.10 Negligible 4-7 I or i(PT) (1) Per Table 18-1-B of the Uniform Building Code (1997 ed.) Per Table 19-A-4 of the Uniform Building Code (1997 ed.) (3) Foundations shall be constructed in accordance with recommendations for the specific categories noted above and presented in the text of this report (PT recommendations) and Table 3. GeoSoils, Inc. TABLE 3 CONVENTIONAL PERIMETER FOOTINGS, SLABS, AND EXTERIOR FLATWORK FOR CALAVERA HILLS, VILLAGE R MINIMUM INTERIOR INTERIOR UNDER GARAGE EXTERIOR :.FOUNDATION, '; FOOTING SLAB - ;REINFORCING SLAB SLAB ,.. SLAB FLATWORK CATEGOAY.. °. SIZE THICKNESS STEEL - -REINFORCEMENT. TREATMENT.. :REINFORCEMENT REINFORCING I 12" Wide 4" Thick 1- #4 Bar Top and #3 Bars @ 2' Sand Over 6" x 6" None x Bottom 24° o.c. 10-MO Polyvinyl (10/10) 12" Deep Both Directions Membrane Over WWF 2" Sand Base II 12" Wide 4" Thick 2- #4 Bars Top and #3 Bars @ 2" Sand Over .6" x 6" 6" x 61- X Bottom 16° o.c. 10-Mil Polyvinyl (6/6) (10/10) 18" Deep Both Directions Membrane Over WWF WWF 2" Sand Base III 12" Wide 4' Thick 2- #5 Bars Top and #3 Bars @ 2" Sand Over Same as 6" x 6° X Bottom 18"o.6 1 G-Mil Polyvinyl interior Slab (6/6) 11 24" Deep Both Directions Membrane Over WWF 2" Sand Base Category Criteria Category I: Max. Fill Thickness is less than 20' and Expansion Index is less than or equal to 50 and Differential Fill Thickness is less than 10' (see note 1). Category II: Max. Fill Thicknesiis less than 50' and Expansion Index is less than or equal to 90 or Differential Fill Thickness is between 10 and 20' (see note 1). Category III: Max. Fill Thickness exceeds 50', or Expansion Index exceeds 90 but is less than 130, 2r Differential Fill Thickness exceeds 20' (see note 1). Notes: 1. Post tension (PT) foundations are required where maximum fill exceeds 50', or the ratio of the maximum fill thickness to the minimum fill thickness exceeds 3:1. Consideration shall be given to using post tension foundations where the expansion index exceeds 90. ' Footing depth measured from lowest adjacent subgrade. Allowable soil bearing pressure is 2,000 PSF. Concrete for slabs and footings shall have a minimum compressive strength of 2,000 PSI (2,500 PSI for exterior flatwork), or adopted UBC mm., at 28 days, using 5 sacks of cement. Maximum Slump shall be 5". Visqueen vapor barrier not required under garage slab. However, consideration shall be given to future uses of the slab area, such as room conversion and/or storage of moisture-sensitive materials. Isolated footings shall be connected to foundations per soils engineer's recommendations (see report). Sand used for base under slabs shall be very low expansive, and have SE > 30. 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 shall be in accordance with correct industry standards and reviewed by the project structural engineer.