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HomeMy WebLinkAboutCT 06-27; MUROYA SUBDIVISION; FINAL REPORT OF TESTING & OBSERVATION PERFORMED DURING SITE GRADING; 2012-06-07" FrA FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING MUROYA PROPERTY BUILDINGS 1 THROUGH 37 CARLSBAD, CALIFORNIA S I PREPARED FOR : TAYLOR WOODROW HOMES INCORPORATED IRVINE, CALIFORNIA JUNE 7,2012 PROJECT NO. 07671-52-02 GEOCON I N.0 0 R P0 RATE D GEOTECHNICAL • ENVIRONMENTAL • M A T E R I A I S Project No. 07671-52-02 June 7; 2012 Taylor Woodrow Homes Incorporated 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Attention: Mr. Tom Baine Subject: FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING MUROYA PROPERTY BUILDINGS 1 THROUGH 37 CARLSBAD, CALIFORNIA Dear Mr. Baine: In accordance with your request and our Proposal No. (LG-1 1175) dated June 20, 2011, we have provided testing and observation services during grading operations for the subject development. The grading operations for the subject lots have been completed and is the subject of this report. We performed our services during the period of November 30, 2011 through May 25, 2012. The scope of our services summarized in this report includes: Observing the grading operations, including the removal and/or processing of topsoil, colluvium, and alluvium and the undercutting lots to expose formational Very Old Paralic Deposits. Observing removal excavations during remedial grading operations, performing field mapping, and providing geotechnical engineering consultation services. Performing in-place density tests on fill soil placed and compacted at the site. Performing laboratory tests to aid in evaluating the maximum dry density and optimum moisture content of the compacted fill. Additionally, we performed laboratory tests on samples of soil present within approximately 3 feet of finish grade to evaluate expansion characteristics and water-soluble sulfate content. Preparing a Final As-Graded Geologic Map. Preparing this final report of grading. 6960 Flanders Drive • Son Diego, California 92121.2974 • Telephone 858.558.6900 • Fox 858.558.6159 GENERAL The purpose of this report is to document that the grading for Building Pads 1 through 37 within the Muroya Property has been performed in substantial conformance with the recommendations of the project geotechnical report and that fill materials have been properly placed and compacted. The Muroya Property development is located on the west side of Black Rail Road and south of Corte Orchidia in Carlsbad, California (see Vicinity Map, Figure 1). The grading contractor for the project was Reed Thomas Company Inc. of Santa Ana, California. We used an electronic version of the grading plans, provided by Pangaea Land Consultants, as the base map for our Final As-Graded Geologic Map (Figure 2, map pocket). To aid in preparation of this report we reviewed: Geotechnical Investigation, Muroya Property, Carlsbad, California, prepared by Geocon Incorporated, dated July 14, 2009 (Project No. 07671-52-01). 2. Grading Plans for: Muroya, prepared by Pangaea Land Consultants, Inc., dated October 19, 2011, Drawing No. 471-7A (Project No. CT 06-27). References to elevations and locations herein were based on surveyor's or grade checker's stakes in the field and interpolation from the referenced grading plans. Geocon Incorporated did not provide surveying services and, therefore, has no opinion regarding the accuracy of the elevations or surface geometry with respect to the approved plans. GRADING Grading began with the removal of existing structures, utilities, brush, and vegetation from the area to be graded. Following these removals, topsoil, alluvium, colluvium, and undocumented fill were removed for re-use as fill materials. The exposed formational Very Old Paralic Deposits were then scarified, moisture conditioned as necessary, and compacted, prior to receiving fill. Grading consisted of removals varying from 3 to 10 feet to expose the Very Old Paralic Deposits and placing fill thicknesses varying from 3 to approximately 24 feet. The subject building pads are underlain by compacted fill overlying the Very Old Paralic Deposits (formerly described as Lindavista Formation). Undercutting operations were performed within planned cut areas for building pads and roadways. Fill materials derived from onsite excavations were placed and compacted in layers until the design elevations were attained. Lots with cut-fill transitions exposed at grade were undercut a minimum of 3 feet and replaced with properly compacted fill. In general, on-sit fill materials consist of silty, fineto medium sand. Fill soil was moisture conditioned as necessary, mixed during placement, and compacted using conventional heavy-duty grading equipment. Project No. 07671-52-02 -2 - June 7, 2012 Due to undercutting operations performed for Verdura Walls No. 8 and 14 (Building Pads 17 through 18, and 35 through 37, respectively), the maximum differential fill thickness for building pads located adjacent to these walls are approximately 5 to 14 feet. In conjunction with the construction of Verdura Wall No. 8, a maximum fill soil of approximately 5 to 11 feet was placed within Building Pads 17 and 18 to achieve finish pad grade elevations ranging from 327 to 328 feet above Mean Sea Level (MSL). A maximum fill thickness of approximately 22 to 24 feet was placed within Building Pads 35 through 37 (model building pads) during the construction of Verdura Wall No. 14, to achieve finish pad grade elevations ranging from 338 to 339 feet MSL. During grading operations, we observed compaction procedures and performed in-place density tests to evaluate the dry density and moisture content of the fill materials. In conjunction with the grading operations, we also provided testing and observation services during the construction of Verdura Walls No. 8 and 14. We performed the in-place density tests in general conformance with ASTM Test Method D 6938 (nuclear). The results of the in-place dry density and moisture content tests are summarized on Table I. In general, the in-place test results indicate the fill soil has a dry density of least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content at the locations tested. The approximate locations of the in-place density tests are shown on the Final As-Graded Geologic Map, Figure 2. Table I includes in-place density and moisture content test results performed during the construction of the Vendura Walls and the overall grading of the development. We selected laboratory tests on samples of material used for fill to evaluate moisture-density relationships from mass grading operations. In addition, we obtained samples used for fill to evaluate expansion potential (ASTM D 4829) and water-soluble sulfate content (California Test No. 417). The results of the laboratory tests are summarized on Tables II through IV. During the grading operations, excess soil was generated and .stockpiled on Building Pads 13 through 18. Once the stockpile material was removed from these pads, we performed additional testing and observation services to the finish grade pad elevations in order to prepare this final report of grading. SLOPES The project slopes within the planned development consisted of cut and fill slopes constructed at inclinations of 2:1 and 1.5:1 (horizontal: vertical), respectively, or flatter with maximum heights of approximately 10 feet and 55 feet, respectively. We observed the finished cut slopes once the design inclinations were achieved. Slopes should be planted, drained, and maintained to reduce erosion. Slope irrigation should be kept to a minimum to just support the vegetative cover. Surface drainage should not be allowed to flow over the top of slopes. Project No. 07671-52-02 -3 - June 7, 2012 Prior to grading, the debris fill encountered within the planned fill slopes were removed and replaced with compacted fill. Portions of the debris fill remained outside the limits of grading due to the encroachment into sensitive habitat. The remedial grading operations within the slope area located west of Building Pads 35 through 37 (west of Verdura Wall No. 14) was subject to deep removals in order to establish a 1:1 inclination into formational materials. The retaining wall was founded in formational Very Old Paralic Deposits. Debris fill exists on the surface of the descending slope below Wall 14 as shown on Figure 2. The proposed 11/2:1 (horizontal: vertical) fill slope located southwest of Building Pads 23 through 28 was constructed by removing the existing debris fill material and establishing a backcut in dense formational materials. Once the adequate backcut was constructed, a 15-foot-wide keyway was excavated to the removal bottom elevation and a heel drain system was installed at the base of the excavation. In generil, fill slopes were either over-filled and cut back or track-walked with a bulldozer during grading. Fill materials derived from onsite excavations were placed and compacted in layers until the design elevations were attained. Geogrid was placed during the construction of the P/2:l (horizontal: vertical) fill slope located southwest of building pads .23 through 28. The grid consisted of Strata Grid 200 and was placed with a vertical spacing of approximately 3 feet and was placed 10 feet horizontally from the face of slope. SUBDRAINS The contractor installed a canyon subdrain at the approximate location shown on the As-Graded Geologic Map (Figure 2). In addition, the subdrain was "as-built" for location and elevation by the project civil engineer. During grading operations, this subdrain was tied-into the existing emergency overflow spillway/dissipator at the base of the fill slope. The subdrain consists of a 6-inch diameter PVC, Schedule 40, perforated pipe placed in crushed aggregate surrounded by Mirafi 140N filter fabric. The subdrain was placed at least 10 feet below finish grade and constructed at a flow gradient of at least 1 percent. The grading contractor also installed a heel drain system within the keyway of the 11/2:1 (horizontal: vertical) fill slope below Building Pads 23 through 28. The heel drain system was constructed with a 6-inch-diameter PVC, Schedule 40, perforated pipe placed in crushed aggregate surrounded by Mirafi 140N filter fabric. The subdrain extends along the back of the 15-foot-wide keyway with a solid pipe extending out into the open space of the existing canyon drainage at the mid-point of the drain. The subdrain pipe was capped on both ends and was constructed to have a flow gradient towards the mid-point connection. A concrete cutoff wall was constructed at the connection point with the solid pipe. Project No. 07671-52-02 .-4 - June 7, 2012 The subdrains should be maintained regularly to prevent sediment and debris from obstructing the free flow of water of the subdrain system. A concrete headwall should be constructed at the subdrain outlet in open space. SOIL AND GEOLOGIC CONDITIONS The soil and geologic conditions encountered during grading are similar to those described in the project geotechnical report. Undercutting of the lots and the placement of compacted fill (Qcf and Quc) were performed in accordance with recommendations provided in the project geotechnical report. The Final As-Graded Geologic Map, Figure 2, depicts the general geologic conditions observed. Table V presents a summary of the as-graded building pad conditions for the subject lots. The subject pads are underlain by compacted fill ranging in thickness between about 3 to 24 feet overlying formational Very Old Paralic Deposits (formerly named the Lindavista Formation). In general, the compacted fill consist of silty, fine to medium sand. CONCLUSIONS AND RECOMMENDATIONS 1.0 General .1 Based on our observations and test results, it is the opinion of Geocon Incorporated that the grading to which this report pertains has been performed in general conformance with the recommendations of the previously referenced project geotechnical report and the geotechnical requirements of the grading plans. 1.2 We did not observe soil or geologic conditions during grading that would preclude the continued development of the property as planned. Based on laboratory test results and field observations, it is the opinion of Geocon Incorporated the fill observed and tested as part of the grading for this project was generally compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. 1.3 The site is underlain by compacted fill and Very Old Paralic Deposits. We observed the placement of compacted fill during grading operations and performed in-place density tests to evaluate the dry density and moisture content of the fill material. 1.4 Laboratory testing of near-grade soil conditions indicates that the upper approximately 3 feet of soil underlying the subject pads possess a "non-expansive" and "very low" expansion potential (expansion index [El] of 20 or less). In addition, the samples indicate the soil possesses "negligible" water-soluble sulfate content. Project No. 07671-52-02 - 5 - - June 7, 2012 1 .5 The site is considered suitable for the use of conventional foundations with slabs-on-grade, and/or post-tensioned foundation systems. Foundation categories for the subject building pads are presented in Table V. 1.6 Excavations within the fill and the Very Old Paralic Deposits should generally be possible with moderate to heavy effort using conventional heavy-duty equipment. Excavations for utility trenches within formational materials may encounter localized cemented zones that will require very heavy effort to excavate and oversize blocks may be generated. 2.0 Finish Grade Soil Conditions 2.1 Observations and laboratory test results indicate that the prevailing soil conditions within the upper approximately 3 feet of finish grade for the subject building pads is considered to be "non-expansive" (expansion index [El] of 20 or less) as defined by 2010 California Building Code (CBC) Section 1803.5.3. Table 2 presents soil classifications based on the expansion index. Results of the El laboratory tests are presented in Table III and indicate that the soil possesses "very low" expansion potentials (El of 20 or less). TABLE 2 EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (El) Expansion Classification 2010 CBC Expansion Classification 0 -20 Very Low Non-Expansive 21-50 Low Expansive 51 -90 Medium 91 -130 High Greater Than 130 Very High 2.2 We performed laboratory tests on samples of the site materials for the subject building pads to evaluate the percentage of water-soluble sulfate content. Results from the laboratory water-soluble sulfate content tests are presented in Table IV and indicate that the on-site materials at the locations tested possess "negligible" sulfate exposure to concrete structures as defined by 2010 CBC Section 1904.3 and ACT 318-08 Sections 4.2 and 4.3. The presence of water-soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from the Site could yield different concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. Project No. 07671-52-02 -6- June 7, 2012 2.3 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, further evaluation by a corrosion-engineer may be performed if improvements that could be susceptible to corrosion are planned. 3.0 Seismic Design Criteria 3.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the USGS. Table 3 summarizes site-specific design criteria obtained - from the 2010 California Building Code (CBC; Based on the 2009 International Building Code [IBC]), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. The planned buildings and improvements can be designed using a Site Class C where the fill soil beneath building pads is less than 20 feet or Site Class D for building pads with a fill thickness greater than 20 feet. We evaluated the site class in accordance with Section 1613.5.5 of the 2010 CBC. Table VI presents the recommended Site Class for the subject lots. TABLE .3 2010 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2010 CBC Reference Site Class : C D Table 16 13.5.2 Fill Thickness, T '(feet) T<20 T>20 -- Spectral Response —Class B (short), S5 1.218g 1.218g Figure 1613.5(3) Spectral Response - Class B (I sec), S 0.459g 0.459g Figure 16 13.5(4) Site Coefficient, F. - 1.000 1.013 Table 1613.5.3(1) Site Coefficient, F 1.341 1.541 Table 1613.5.3(2) Maximum Considered Earthquake 1.218g 1.234g Section 1613.5.3 (Eqn 16-36) Spectral Response Acceleration (short), s s Maximum Considered Earthquake 0.616g 0.708g Section 1613.5.3 (Eqn 16-37) Spectral Response Acceleration—(1 sec), 5M1 5% Damped Design Spectral Response Acceleration (short), 5DS 0.812g 0.823g Section 1613.5.4 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (1 sec), 5D1 0.41 Ig 0.472g Section 1613.5.4 (Eqn 16-39) 3.2 Conformance to the criteria in Table 3 for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure willnot occur if a maximum level earthquake occurs. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive. Project No. 07671-52-02 -7- June 7, 2012 4.0 Foundation and Concrete Slabs-On-Grade Recommendations 4.1 The foundation recommendations herein are for proposed one- to three-story residential structures. The foundation recommendations have been separated into three categories based on either the maximum and differential fill thickness or Expansion Index. The foundation category criteria are presented in Table 4.1. TABLE 4.1 FOUNDATION CATEGORY CRITERIA Foundation Category Maximum Fill Thickness, T (Feet) Differential Fill Thickness, D (Feet) Expansion Index (El) I T.c20 -- EI<50 II 20<T<50 10<D<20 50<EI<90 III T~50 D~20 90<EI<130 4.2 Table 4.2 presents minimum foundation and interior concrete slab design criteria for conventional foundation systems. TABLE 4.2 CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Minimum Footing Embedment Depth Continuous Footing Interior Slab Category (inches) Reinforcement Reinforcement 1 12 Two No. 4 bars, 6 x 6 - 10/10 welded wire one top and one bottom mesh at slab mid-point II 18 Four No. 4 bars, No. 3 bars at 24 inches two top and two bottom on center, both directions III 24 Four No. 5 bars, - No. 3 bars at 18 inches two top and two bottom I on center, both directions 4.3 The embedment depths presented in Table 4.2 should be measured from the lowest adjacent pad grade for both interior and exterior footings. The conventional foundations should have a minimum width of 12 inches and 24 inches for continuous and isolated footings, respectively. Figure 3 presents a wall/column footing dimension detail. 4.4 The concrete slab-on-grade should be a minimum of 4 inches thick for Foundation Categories I and II and 5 inches thick for Foundation Category III. Project No. 07671-52-02 -8 - . June 7, 2012 4.5 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture- sensitive materials should be underlain by a vapor retarder. The vapor retarder design should be consistent with the guidelines presented in the American Concrete Institute's (ACT) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACT 302.2R-06). In addition, the membrane should be installed in accordance with manufacturer's recommendations and ASTM requirements and installed in a manner that prevents puncture. The vapor retarder used should be specified by the project architect or developer based on the type of floor covering that will be installed and if the structure will possess a humidity- controlled environment. 4.6 Placement of I to 2 inches of sand is common practice in Southern California. The foundation engineer (the post-tensioned design engineer) should provide appropriate concrete mix design criteria and curing measures that may be utilized to assure proper curing of the slab to reduce the potential for rapid moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation engineer present concrete mix design and proper curing methods on the foundation plans. It is critical that the foundation contractor understands and follows the recommendations presented on the foundation plans. 4.7 As an alternative to the conventional foundation recommendations, consideration should be given to the use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The post-tensioned systems should be designed by a structural engineer experienced in post-tensioned slab design and design criteria of the Post- Tensioning Institute (Fr!), Third Edition, as required by the 2010 California Building Code (CBC Section 1808.6). Although this procedure was developed for expansive soil conditions, it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post-tensioned design should incorporate the geotechnical parameters presented on Table 4.3 for the particular FoundatiOn Category designated. The parameters presented in Table 4.3 are based on the guidelines presented in the PTI, Third Edition design manual. Project No. 07671-52-02 1 .-9- June 7, 2012 TABLE 4.3 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS Post-Tensioning Institute (PT!) Third Edition Design Parameters Foundation Category i ii iii Thornthwaite Index -20 -20 -20 Equilibrium Suction 3.9 3.9 3.9 Edge Lift Moisture Variation Distance, e 1 (feet) 5.3 5.1 4.9 Edge Lift, YM (inches) 0.61 1.10 1.58 Center Lift Moisture Variation Distance, em (feet) 9.0 9.0 9.0 Center Lift, y (inches) 0.30 0.47 0.66 4.8 Foundation systems for the building pads that possess a foundation Category I and a "very low" expansion potential (expansion index of 20 or less) can be designed using the method described in Section 1808 of the 2010 CBC. If post-tensioned foundations are-planned, an alternative, commonly accepted design method (other than PTI Third Edition) can be used. However, the •post-tensioned foundation system should be designed with a total and differential deflection of 1 inch. Geocon Incorporated should be contacted to review the plans and provide additional information, if necessary. 4.9 The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. If a post-tensioned mat foundation system is planned, the slab should possess a thickened edge with a minimum width of 12 inches and extend below the clean sand or crushed rock layer. 4.10 If the structural engineer proposes a post-tensioned foundation design method other than PTI, Third Edition: The deflection criteria presented in Table 4.3 are still applicable. Interior stiffener beams should be used for Foundation Categories II and III. The width of the perimeter foundations should be at least 12 inches. The perimeter footing embedment depths should be at least 12 inches, 18 inches and 24 inches for foundation categories I, II, and III, respectively. The embedment depths should be measured from the lowest adjacent pad grade. 4.11 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift, regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI design procedures primarily address the potential center lift of slabs but, because of the Project No. 07671-52-02 - 10- June 7, 2012 placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after tensioning reduces the ability of the system to mitigate edge lift. The structural engineer should design the foundation system to reduce the potential of edge lift occurring for the proposed structures. 4.12 During the construction of the post-tension foundation system, the concrete should be placed monolithically.. Under no circumstances should cold joints form between the footings/grade beams and the .slab during the construction of the post-tension foundation system. 4.13 Category I, II, or III foundations may be designed.for an allowable soil bearing pressure of 2,000 pounds per square foot (p50 (dead plus live load). This bearing pressure may be increased by one-third for transient loads due to wind or seismic forces. 4.14 Isolated footings, if present,. should have the minimum embedment depth and width recommended for conventional foundations for a particular foundation category. The use of isolated footings, which are located beyond the perimeter of the building and support structural elements connected to the building, are not recommended for Category III. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams. 4.15 For Foundation Category III, consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to, reduce the potential for future separation to occur. 4.16 Foundation excavations should be observed by the geotechnical engineer (a representative of Geocon Incorporated) prior to the placement of reinforcing steel to check that the exposed soil conditions are similar to those expected and that they have been extended to the appropriate bearing strata. If unexpected soil conditions are encountered, foundation modifications may be required. 4.17 Special subgrade presaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary, to maintain a moist condition as would be expected in such concrete placement. Project No. 07671-52-02 - 11 - June 7, 2012 4.18 Where buildings or other improvements are planned near the top of a slope steeper than 3:1 (horizontal: vertical), special foundations and/or design considerations are recommended due to the tendency for lateral soil movement to occur. For fill slopes less than 20 feet high, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. When located next to a descending 3:1 (horizontal: vertical) fill slope or steeper, the foundations should be extended to a depth where the minimum horizontal distance is equal to H/3 (where H equals the vertical distance from the top of the fill slope to the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The horizontal distance is measured from the outer, deepest edge of the footing to the face of the slope. An acceptable alternative to deepening the footings would be the use of a post-tensioned slab and foundation system or increased footing and slab reinforcement. Specific design parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined. If a swimming pool is proposed, Geocon Incorporated should be contacted to review the plans and the specific site conditions to provide additional recommendations, if necessary. Swimming pools located within 7 feet of the top of cut or' fill slopes are not recommended. Where such a condition cannot be avoided, the portion of the swimming pool wall within 7 feet of the slope face be designed assuming that the adjacent soil provides no lateral support. This recommendation applies to fill slopes up to 30 feet in height, and cut slopes regardless of height. For swimming pools located near the top of fill slopes greater than 30 feet in height, additional recommendations may be required and Geocon Incorporated should be contacted for a review of specific site conditions. Although other improvements, which are relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures that would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. 4.19 The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soil (if present), differential settlement of existing soil or soil with varying thicknesses. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the Slump of the concrete, proper Project No. 07671-52-02 ' - 12- June 7, 2012 concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. 4.20 Exterior concrete flatwork not subject to vehicular traffic should be constructed in accordance with the recommendations herein. Slab panels should be a minimum of 4 inches thick and, when in excess of 8 feet square, should be reinforced with 6 x 6 - W2.9/W2.9 (6 x 6 - 6/6) welded wire mesh placed in the middle of the slab to reduce the potential for cracking. In addition, concrete flatwork should be provided with crack control joints to reduce and/or control shrinkage cracking. Crack control spacing should be determined by the project structural engineer based on the slab thickness and intended usage. Criteria of the American Concrete Institute (ACI) should be taken into consideration when establishing crack control spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted in accordance with criteria presented in the grading section prior to concrete placement. Subgrade soil should be properly compacted and the moisture content of subgrade soil should be checked prior to placing concrete. Base or sand bedding is not required beneath the flatwork. 4.21 Even with the incorporation of the recommendations within this report, exterior concrete flatwork has a potential of experiencing some movement due to swelling or settlement; therefore, welded wire mesh should overlap continuously in flatwork. Additionally, flatwork should be structurally connected to curbs, where possible. 4.22 Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. 5.0 Retaining Walls and Lateral Loads 5.1 Retaining walls not restrained at the top and having a level backfill surfaëe should be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of 35 pounds per cubic foot (pctT). Where the backfill will be inclined at no steeper than 2:1 (horizontal: vertical), an active soil pressure of 50 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1:1 plane extending upward from the base of the wall possess an expansion index of 50 or less. For those buildings with finish-grade soils having an expansion index greater than 50 and/or where backfill materials do not conform to the criteria herein, Geocon Incorporated should be consulted for additional recommendations. 5.2 Unrestrained walls are those that are allowed to rotate more than 0.00IH (where H equals the height of the retaining portion of the wall) at the top of the wall. Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf should be Project No. 07671-52-02 - 13- June 7, 2012 added to the above active soil pressure. For retaining walls subject to vehicular loads within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to 2 feet of fill soil should be added. 5.3 Retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and waterproofed as required by the project architect. The use of drainage openings through the base of the wall (weep holes) is not recommended where the seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of the wall. The above recommendations assume a properly compacted free-draining backfill material (El of 50 or less) with no hydrostatic forces or imposed surcharge load. Figure 4 presents a typical retaining wall drainage detail. If conditions different than those described are expected, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. 5.4 In general, wall foundations founded in properly compacted fill or formational materials should possess a minimum depth and width of one foot and may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within three feet below the base of the wall has an expansion index of 90 or less. The proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where such a condition is expected. 5.5 The structural engineer should determine the seismic design category for the project in accordance with Section 1613 of the 2010 CBC. If the project possesses a seismic design category of D, E, or F, the proposed retaining walls should be designed with seismic lateral pressures. The seismic load exerted on the wall should be a triangular distribution with a pressure of 25H (where H is the height of the wall, in feet, resulting in pounds per square foot [psf]) exerted at the base of the wall and zero at the top of the wall. We used a peak site acceleration of 0.33g calculated from Section 1803.5.12 of the 2010 California Building Code (Ss/2.5) and applying a pseudo-static coefficient of 0.5. 5.6 Footings that must be placed within seven feet of the top of slopes should be extended in depth such that the outer bottom edge of the footing is at least seven feet horizontally inside the face of the slope. 5.7 To resist lateral loads, a passive pressure exerted by an equivalent fluid weight of 350 pounds per cubic foot (pcf) should be used for the design of footings or shear keys poured neat in compacted fill. The passive pressure assumes a horizontal surface extending at least 5 feet, or three times the surface generating the passive pressure, whichever is Project No. 07671-52-02 - 14 - June 7, 2012 greater. The upper 12 inches of material in areas not protected by floor slabs or pavement should not be included in design for passive resistance. 5.8 If friction is to be used to resist lateral loads, an allowable coefficient of friction between soil and concrete of 0.4 should be used for design. 5.9 The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or other types of walls are planned, such as crib-type walls, Geocon Incorporated should be consulted for additional recommendations. 6.0 Mechanically Stabilized Earth (MSE) Retaining Walls 6.1 MSE retaining walls are alternative walls that consist of modular block facing units with geogrid-reinforced earth behind the block. The geogrid attaches to the block units and is typically placed at specified vertical intervals and embedment lengths. Spacing and lengths are based on the type and strength characteristics of soil used for the backfill. MSE walls should be designed for any surcharge loads due to ascending fill slopes or building loads as deemed necessary by the structural engineer and wall designer. 6.2 Based on information obtained from the referenced geotechnical investigation report, the geotechnical parameters provided in Table 6 can be used for design of the MSE walls. TABLE 6 GEOTECHNICAL PARAMETERS FOR GEOSYNTHETIC REINFORCED WALLS Parameter Reinforced Zone Retained Zone Foundation Zone Angle of Internal Friction 30 degrees 30 degrees 30 degrees Cohesion 300 psf 300 psf 300 psf Wet Unit Weight 130 pcf 130 pcf 130 pcf 6.3 The soil parameters presented in Table I are based on our experience and direct shear- strength tests performed during the geotechnical investigation and previous grading operations and represent some of the on-site materials. The wet unit weight values presented in Table I can be used for design but actual in-place densities may range from approximately 110 to 145 pounds per cubic foot. Geocon Incorporated has no way of knowing whether these materials will actually be used as backfill behind the wall during construction. It is up to the wall designers to use their judgment in selection of the design parameters. As such, once backfill materials have been selected and/or stockpiled, Project No. 07671-52-02 - IS - June 7, 2012 sufficient shear tests should be conducted on samples of the proposed backfill materials to check that they conform to actual design values. Results should be provided to the designer to re-evaluate stability of the walls. Dependent upon test results, the designer may require modifications to the original wall design (e.g., longer reinforcement embedment lengths). 6.4 For walls founded on and retaining compacted fill, the angle of internal friction recommended for the reinforced zone should also be used for the retained zone and foundation zone. The foundation zone is the area where the footing is embedded, the reinforced zone is the area of the backfill that possesses the reinforcing fabric, and the retained zone is the area behind the reinforced zone. 6.5 An allowable soil bearing pressure of 2,000 psf (pounds per square foot) should be used for foundation design and calculations for wall bearing. This bearing pressure assumes a minimum foundation width and depth of 12 inches founded in compacted fill or formational materials. The allowable soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil bearing pressure of 4,000 psf. 6.6 Backfill materials within the reinforced zone should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557-02. This is applicable to the entire embedment width of the geogrid reinforcement. Typically, wall designers specify no heavy compaction equipment within 3 feet of the face of the wall. However, smaller equipment (e.g., walk-behind, self-driven compactors or hand whackers) can be used to compact the materials without causing deformation of the wall. If the designer specifies no compactive effort for this zone, the materials are essentially not properly compacted and the geogrid within the uncompacted zone should not be relied upon for reinforcement, and overall embedment lengths will have to be increased to account for the difference. 6.7 The wall should be provided with a drainage system sufficient to prevent excessive seepage through the wall and the base of the wall, thus preventing hydrostatic pressures behind the wall. 6.8 Geosynthetic reinforcement must elongate to develop full tensile resistance. This elongation generally results in movement at the top of the wall. The amount of movement is dependent upon the .height of the wall (e.g., higher walls rotate more) and the type of geogrid reinforcing used. In addition, over time geogrid has been known to exhibit creep (sometimes as much as 5 percent) and can undergo additional movement. Given this Project No. 07671-52-02 - 16- . June 7, 2012 condition, the owner should be aware that structures and pavement placed within the reinforced and retained zones of the wall may undergo movement. 7.0 Slope Maintenance 7.1 Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions which are both difficult to prevent and predict, be susceptible to near surface (surficial) slope instability. The instability is typically limited to the outer three feet of a portion of the slope and usually does not directly impact the improvements on the pad areas above or below the slope. The occurrence of surficial instability is more prevalent on fill slopes and is generally preceded by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage. The disturbance and/or loosening of the surficial soils, as might result from root growth, soil expansion, or excavation for irrigation lines and slope planting, may also be a significant contributing factor to surficial instability: It is, therefore, recommended that, to the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or properly recompacted, (b) irrigation systems be periodically inspected and maintained to eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be periodically maintained to preclude ponding or erosion. It should be noted that although the incorporation of the above recommendations should reduce the potential for surficial slope instability, it will not eliminate the possibility, and, therefore, it may be necessary to rebuild or repair a portion of the projects slopes in the future. 8.0 Site Drainage 8.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed away from structures in accordance with 2010 CBC 1804.3 or other applicable standards. In addition, surface drainage should be directed away from the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. 8.2 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks for early detection of water infiltration and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for a prolonged period of time. 8.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for surface or irrigation water to infiltrate the pavement's subgrade and base course. We recommend that drains to collect excess irrigation water and transmit it to drainage Project No. 07671-52-02 -17- June 7, 2012 structures, or impervious above-grade planter boxes be used. In addition, where landscaping is planned adjacent to the pavement, we recommended construction of a cutoff wall along the edge of the pavement that extends at least 6 inches below the bottom of the base material. 8.4 If detention basins, bioswales, retention basins, water infiltration or low impact development (LID) devices are being considered, Geocon Incorporated should be retained to provide recommendations pertaining to the geotechnical aspects of possible impacts and design. Distress may be caused to planned improvements and properties located hydrologically downstream. The distress depends on the amount of water to be detained, its residence time, soil permeability, and other factors. We have not performed a hydrogeology study at the site. Downstream properties may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other impacts as a result of water infiltration. 8.5 Based on previous calculated infiltration rates, the existing soil may not be conducive to water infiltration. In addition, basins that are located adjacent to the planned structures and where distress could occur from infiltration, the storm water management devices should be properly constructed to prevent water infiltration. The planned retention basin areas should be lined with an impermeable liner (e.g. High-density polyethylene, HDPE, with a thickness of about 12 mil or equivalent Polyvinyl Chloride, PVC, liner). 8.6 We do not expect water will infiltrate the fill or formational materials within the paver pavement areas. The paver areas should be setback from the planned structures at least 5 feet. However, the subgrade should be graded to allow water to flow to a subdrain. The subdrain should be placed at the bottom of the base section along the low point of the driveway to reduce the potential for water to build up within the paving section. The drain should be connected to a drainage device as determined by the project civil engineer. Impermeable liners located below the paver section will not be required if the payers are installed as recommended herein. The drain should consist of a 3-inch diameter perforated Schedule 40, PVC pipe wrapped in filter fabric and placed adjacent to the concrete band. LIMITATIONS The conclusions and recommendations contained herein apply only to our work with respect to grading, and represent conditions at the date of our latest observation on May 25, 2012. Any subsequent grading should be done in conjunction with our observation and testing services. As used herein, the term "observation" implies only that we observed the progress of the work with which we agreed to be involved. Our services did not include the evaluation or identification of the potential presence of hazardous or corrosive materials. Our conclusions and opinions as to whether the work Project No. 07671-52-02 - 18- June 7, 2012 essentially complies with the job specifications are based on our observations, experience, and test results. Subsurface conditions, and the accuracy of tests used to measure such coiditions, can vary greatly at any time. We make no warranty, express or implied, except that our services were performed in accordance with engineering principles generally accepted at this time and location. We will accept no responsibility for any subsequent changes made to the site by others, by the uncontrolled action of water, or by the failure of others to properly repair damages caused by the uncontrolled action of water. The findings and recommendations of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and Should not be relied upon after a period of three years. If you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, 4v?FoyWeedon oFESS JOHN GEOCONI CORPORATED HOOBS ,4HALG\ t4 WE GE2714 Exp. O6 No. 271 Floobs CL N6.1524 iCI (* ( CERTIFIED ) * Cr-'. ENGINEERING / GEOLOGIST . SFW:JH:AG:vb OFCA (2/del) Addressee Project No. 07671-52-02 - 19- June 7. 2012 , \c 6-1 t It- 40 loll iv 401 46 rw ) _• * • I I 4 J 9 •'. i_J'1,e " r- •'-. —-'. rLDyJP-, ,, I91 It 44I " - i- I • • (1 / -.4t' _-;-.t_ •..-. t);,t, t.-I I ' I t 1 sr r ,-. •'. ' I t' ..-.4•-. \ ih1Lr ALl _______ Ij - FIG.1 PAD GRADE SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI CONCRETE SLAB L FOOTING WIDTH SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI CONCRETE SLAB 4 4 4 / .-.....-. 4 .....:.:' ............ 4 1 F CL 8 / I.—=-- -----V LL 4 A : FOOTING WIDTH* '4.S. 41 4.. •- ......... •g-• :.' .•... 4 • / A4 : _ *....SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION NO SCALE I WALL / COLUMN FOOTING DIMENSION DETAIL I GEOCON MUROYA PROPERTY INCORPORATED 40D BUILDINGS 1 THROUGH 37 GEOTECHNICAL u ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 CARLSBAD, CALIFORNIA PHONE 858 558-6900 - FAX 858 558-6159 AG IRS DSKIGTYPD DATE 06-07-2012 PROJECT NO. 07671 -52-02 FIG. 3 COIFOOT2DWG Y:\PROJECTS\07671-52-02 MUROVA PROPERTY\DETAILS\07671-52-02_COLFOOT2_Upd 06-07-2012.dwg w GEOCON MUROYA PROPERTY • 5 INCORPORATED BUILDINGS 1 THROUGH 37 CARLSBAD, CALIFORNIA GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 11 1 AG IRS DSKJGTYPD DATE 06 -07- 2012 PROJECT NO..07671 -52-02 FIG. 4 5 RWDD_2 Y:pROJECTS\07671-52-02 MIJROYA PROPERTV\DETAILS107671-52-02_RWDD_2_Upd TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location Elev. or Depth (ft) Curve No. Plus 3/4" Rock (%) Field Dry Dens. (pci) Field Moist. Cont. (%) Field Rel. Comp. (%) Rec1'd. Rd. Comp. (%) SZ I 11/30/I1 N of Building Pad 35 324 2 0 118.1 10.2 92 90 2 11/30/11 Building Pad 35 325 2 0 120.0 9.8 94 90 3 12/01/I1 \V of Building Pad 37 324 2 0 120.Q II.! 94 90 4 12/01/1I E of Building Pad 35 330 I 0 109.9 12.9 92 90 5 12/01/1I NofBuilding Pad 35 331 .1 0 110.1 12.3 92 90 6 12/01/1I E of Building Pad 36 328 2 0 116.7 10.6 91 90 7 12/01/1I Sweetclover Lane 15+30 332 2 0 116.1 10.8 91 90 8 12/01/1I Building Pad 36 331 2 0 114.4 8.7 89 90 8A 12/01/I1 Building Pad 36 331 2 0 116.0 10.1 91 90 9 12/02/I1 Building Pad 35 335 2 0 114.9 11.7 90 90 10 12/02/I1 Building Pad 37 337 2 0 115.2 10.4 90 90 II 12/02/I1 S of Building Pad 34 332 2 0 116.4 10.1 91 90 12 12/02/1I WofBuiIding Pad 34 329 2 0 115.0 11.7 90 90 13 12/05/1I Sweetclover Lane 12+40 332 2 0 121.0 9.5 95 90 14 12/05/I1 SW of Building Pad 34 330 2 0 118.3 9.8 92 90 IS 12/05/I1 Building Pad 33 . 333 2 0 120.1 9.3 94 90 16 12/05/I1 SEofBuilding Pad 34 336 2 0 116.1 9.4 91 90 17 12/05/I1 SEofBuilding Pad 34 337 2 0 116.6 9.1 91 90 IS 12/06/I1 SE of Building Pad 29 331 2 0 122.1 9.0 95 90 19 12/06/1I N\VofBuilding Pad 29 332 2 0 115.7 10.6 90 90 20 12/06/1 I SW of Building Pad 26 333 2 0 116.7 9.9 91 90 21 12/06/1I NWofBuilding Pad 26 334 2 0 116.0 9.4 91 90 22 12/07/I1 Building Pad 24 332 2 0 115.4 10.0 90 90 23 12/07/I1 Building Pad 26 335 I 0 108.6 14.1 91 90 24 12/07/I1 NE of Building Pad 24 332 2 0 . 115.2 10.2 90, 90 25 12/07/I1 NE of Building Pad 25 334 2 0 117.0 9.3 91 90 SZ 26 12/08/11 Wall S Basin 303 2 0 118.2 9.2 92 90 27 12/08/I1 Wall 8 Bain 305 2 0 115.9 9.3 91 90 SZ 28 12/08/1I Wall 8 Basin 308 2 0 117.1 9.0 92 90 29 12/08/1I Wall 8 Iasin 309 2 0 115.2 9.4 90 90 30 12/09/1I Wall 8 Basin 310 2 0 120.1 11.6 94 90 SZ 31 12/09/I1 Wall 8 Basin . 313 2 0 116.5 12.5 91 90 32 12/09/I1 Wall 8 Basin 314 2 0 117.4 11.7 92 90 33 12/09/I1 Wall 8 Basin 315 2 0 117.7 10.1 92 90 34 12/09/I1 Building Pad IS 315 2 0 115.0 12.0 90 90 35 12/09/I1 Wall 8 Basin 316 2 0 115.8 10.4 91 90 36 12/14/I1 Sof Building Pad 12 335 'I 0 109.0 14.2 91 90 37 12/14/I1 S of Building Pad 9 337 I 0 107.7 15.9 90 90 SZ 38 12/14/1I Wall Basin 317 2 0 115.1 11.4 90 90 SZ 39 12/14/I1 Wall 8 Basin . 318 2 0 116.4 10.9 91 90 SZ 40 12/15/I I Wall 8 Basin . 320 I 0 107.8 13.2 90 90 SZ 41 12/15/11 Wall 8 Basin . 320 1 0 108.6 13.1 91 90 SZ 42 12/15/1 1 Wall 8 Basin 321 2 0 116.6 10.2 91 90 43 12/15/I1 Building Pad IS 322 I 0 109.0 13.1 91 90 44 12/15/1I WofBuilding Pad 17 321 2 0 115.4 9.7 90 90 Project No. 07671-52-02 June 7, 20 12 TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location . Elev. or Depth (It) Curve No. Plus 3/4 Rock (°"°) Field Dry Dens. (peD Field Moist. Cont. (%) Field Re 1. Comp. (%) Rcq'd. Rel. Comp. I (%) 45 12/16/1I W of Building Pad IS 323 1 0 107.9 13.1 90 90 46 12/16/1I Sof Building Pad 17 325 I 0 108.7 13.4 91 . 90 SZ 47 12/16/1I Wall S Basin . 324 2 0 118.1 9.4 92 90 SZ 48 12/16/I1 Wall 8 Basin 321 2 0 115.9 9.9 91 90 SZ 49 12/16/I1 Wall S Basin 324 2 0 117.2 9.0 92 90 50 12/19/I1 WofBuilding Pad 35 328 1 0 107.8 15.2 90 90 SZ SI 12/19/I1 SW of Building Pad 37 327 I 0 110.4 14.4 92 90 SZ 52 12/19/1I NW of Building Pad 35 331 I 0 108.2 12.1 90 90 SZ 53 12/19/I1 W of Building Pad 36 330 2 0 115.6 11.4 90 90 SZ 54 12/20/11 W of Building Pad 35 334 2 0 116.2 10.4 91 90 SZ 55 12/20/I1 W of Building Pad 37 333 2 0 112.7 7.5 88 90 SZ 55A 12/20/I1 W of I3uiIding Pad 37 333 2 0 114.9 10.8 90 90 56 . 12/20/I1 NW of Building Pad 36 336 I 0 111.0 12.5 93 90 57 12/21/I1 Buitding Pad 35 . 337 I 0 108.8 13.1 91 90 58 12/21/I1 Building Pad 37 338 1 0 109.2 12.8 91 90 59 12/21/I1 NW of Building Pad 12 337 2 0 119.0 9.6 93 90 60 12/21/I1 Building Pad 9 338 2 0 115.8 11.0 91 90 61 12/22/1I Building Pad 21 327 2 0 117.0 9.9 91 90 62 12/22/11 NE of Building Pad 23 328 2 0 115.4 11.2 90 90 63 12/22/1I Building Pad 27 334 2 0 118.3 11.9 92 90 64 12/22/1I EofBuilding Pad 2S 335 1 0 108.7 14.1 91 90 SZ 65 12/23/11 SW of Building Pad 25; Keyway 286 I 0 . 107.6 12.0 90 90 SZ 66 12/23/11 SW of I3uilding Pad 25; Keyway 289 1 0 107.5 13.9 90 90 SZ 67 12/27/I1 SW of Building Pad 25; Keyway 293 2 0 115.7 10.5 90 90 SZ 6$ 12/27/I1 SW of Building Pad 25; Keyway 296 2 0 116.0 11.0 91 90 SZ 69 12/27/I1 SW of Building Pad 25; Keyway 298 2 0 117.2 11.7 92 90 SZ 70 12/27/11 SW of Building Pad 24; Keyway 301 2 0 118.0 11.2 92 90 SZ 71 12/27/I1 SW of Building Pad 25; Keyway 303 2 0 116.7 10.5 91 90 SZ 72 12/27/11 SW of Building Pad 24; Keyway 303 2 0 116.5 11.8 91 90 SZ 73 12/28/I1 SW of Building Pad 26; Keyway 305 I 0 109.0 14.6 91 90 SZ 74 12/28/11 SW of Building Pad 25 305 I 0 109.8 12.4 92 90 ST 75 12/28/I1 Wall 8 Basin 317 I 0 111.8 12.8 93 90 ST 76 12/25/I1 Wall Basin 320 2 0 117.4 11.2 92 90 SZ 77 12/28/11 SW of Building Pad 24 308 2 0 117.9 10.1 92 90 SZ 78 12/28/I V SW of Building Pad 26 308 1 0 108.5 12.6 90 90 SZ 79 12/28/I1 SW of Building Pad 27 311 2 0 115.8 11.0 91 90 SZ $0 12/28/I1 SW of Building Pad 24 311 I 0 112.0 13.2 93 90 SZ SI 12/28/I1 SW of Building Pad 25 314 2 0 115.6 10.8 90 90 SZ $2 12/25/I1 SW of Building Pad 26 314 2 0 115.8 10.1 91 90 83 12/29/I1 S of Building Pad 15 325 I 0 107.7 14.3 90 90 84 12/29/11 Building Pad 14 326 2 0 118.6 11.0 93 90 85 12/29/1I WofBuilding Pad 15 325 2 0 116.9 10.3 91 90 86 12/29/I1 SE of BLlilding Pad IS 326 2 0 119.4 9.4 93 90 ST 87 12/30/I1 SW of Building Pad 26 313 I 0 107.9 12.6 90 90 ST 88 12/30/I1 SW of Building Pad 24 309 2 0 116.6 11.0 91 90 Project No. 07671-52-02 . June 7, 2012 TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Elev. . Plus Field Field Field Reqd. or 3/4" Dry Moist. Rd. Rd. Depth Curve Rock Dens. Cont. Comp. Comp. Location (It) No. (%) . (pc I) (%) (%) (%) 89 12/30/11 Building Pad 16 326 2 0 115.6 12.0 90 90 90 12/30/I1 W of Building Pad 13 328 2 0 117.3 11.5 92 90 91 12/30/1I SW oil3uilding Pad 24 317 I 0 108.1 13.1 90 90 92 12/30/1I SWoil3uilding Pad 25 317 I 0 108.1 13.8 90 90 93 12/30/11 SW of Building Pad 27 .• 317 I 0 109.8 14.2 92 90 94 01/03/12 SW of Building Pad 26 319 1 0 109.8 12.0 92 90 95 01/03/12 SW of Building Pad 24 320 1 0 106.0 9.4 88 . 90 95 A 01/03/12 SW of Building Pad 24 320 I 0 108.4 12.5 90 90 96 01/03/12 SW of Building Pad 25 323 1 0 111.4 14.1 93 90 97 01/03/12 SW of Building Pad 29 317 I 0 111.6 12.2 93 90 98 01/03/12 SW of Building Pad 29 320 . I 0 109.8 13.4 92 90 99 01/04/12 SofBuilding Pad 29 322 2 0 115.9 11.9 91 90 100 01/04/12 SW of Building Pad 27 325 2 0 117.5 10.3 92 90 101 01/04/12 SW of Building Pad 24 326 1 0 108.4 12.5 90 90 10 01/04/12 NolBuilcling Pad 15 331 1 0 109.0 12.1 91 90 103 01/04/12 EoI Building Pad 14 332 I 0 108.5 13.0 90 90 104 01/04/12 Wof Building Pad 37 330 2 0 115.8 9.5 .91 90 lOS 01/04/12 Nof Building Pad 35 335 2 0 115.9 10.2 91 90 106 01/04/12 Building Pad 35 338 2 0. 116.7 11.1 91 90 107 01/04/12 Building Pads 36 & 37 339 2 0 117.5 9.1 92 90 lOS 01/04/12 SW of Building Pad 26 328 2 0 121.1 12.0 95 90 109 01/04/12 SW of Building Pad 29 324 2 0 119.3 11.1 93 90 110 01/05/12 SW ol'Building Pad 27 331 2 0 115.9 10.1 91 90 III 01/05/12 SWoiBuiIding Pad 24 331 2 0 117.5 10.5 92 90 112 01/05/12 5 of Building Pad 29 . 325 2 0 116.9 11.0 91 90 113 01/05/12 SW of Building Pad 25 333 2 0 115.8 12.4 91 90 114 01/05/12 SW of Building Pad 29 . 328 2 0 119.2 11.7 93 90 115 01/05/12 Building Pad 25 335 2 0 116.2 11.4 91 90 116 01/05/12 S of Building Pad 29 331 I 0 110.4 15.3 92 90 117 01/05/12 S of Building Pad 29 328 2 0 117.0 10.9 91 90 11$ 01/05/12 Nof Building Pad 14 334 2 0 117.7 10.1 92 90 119 01/05/12 E of Building Pad 13 335 2 0 115.9 11.0 91 90 120 01/06/12 Building Pad 31 . 335 2 0 116.1 11.2 91 90 121 01/06/12 NofBuiIding Pad 32 336 2 0 115.7 11.9 90 90 122 01/09/12 SW of Building Pad 24 321 2 0 116.8 9.4 91 90 123 01/09/1 2 SW of Building Pad 26 329 2 0 118.1 9.0 92 90 124 01/09/12 NofBuilding Pad 30 337 2 0 116.8 9.5 91 90 125 01/09/1 2 N of Building Pad 30 339 2 0 120.1 9.2 94 90 126 01/10/12 Building Pad 28 337 2 0 118.4. 9.7 93 90 127 01/10/12 EofBuilding Pad 27 336 2 0 120.0 9.6 94 90 128 01/10/12 E of Building Pad 24 336 2 0 124.8 9.3 98 90 129 01/10/12 SW oil3uilding Pad 27 325 I 0 111.8 12.7 93 90 130 01/10/12 SW of Building Pad 29 320 2 0 115.9 9.9 91 90 131 01/10/12 SW of Building Pad 29 330 2 0 116.4 11.7 91 90 132 01/10/12 Sof Building Pad I 338 2 0 119.7 10.1 94 . 90 Project No. 07671-52-02 June 7. 2012 Sz Sz Sz Sz Sz Sz Sz Sz Sz Sz Sz Sz Sz ST Si. FG FG Sz Sz Sz SZ SZ SZ Sz Sz Sz Sz ST ST Sz Sz FG FG FG ST ST ST Sz TABLE I SUMMARY OF FIELD DENSITY TEST. RESULTS Test No. Date Location Elev. or Depth (ft) Curve No. Plus 3/4 Rock (%) Field Dry Dens. (pci) Field Moist. Cont. (%) Field Re!. Comp. (%) Reqd. Re!. Comp. (%) 133 01/10/12 N of Building Pad 30; White Sage Way 339 2 0 115.7 9.7 90 90 FG 134 01/11/12 S of Building Pad 29 333 2 0 117.4 9.5 92 90 FG 135 01/11/12 SE of l3uilding Pad 29 332 2 0 117.7 10.0 92 90 FG 136 01/11/12 Building Pads 33&34 334 2 0 121.3 9.0 95 90 FG 137 01/11/12 Building Pad 32 337 2 0 116.2 11.7 91 90 FG 138 01/11/12 Building Pad 30 337 2 0 117.1 9.3 92 90 SZ 139 01/11/12 Eof Building Pad 14 337 2 0 116.7 10.7 91 90 SZ 140 01/12/12 E of Building Pd 5 340 2 0 115.9 9.9 91 90 SZ 141 01/12/12 Eof Building Pad 35 341 I 0 108.7 14.9 91 90 142 01/12/12 SE of Building Pad I 343 2 0 116.0 9.9 91 90 SZ 143 01/12/12 NofBuilcliiig Pad 4 341 2 0 115.9 10.2 91 90 SZ 144 01/13/12 E of I3uiIding Pad I 345 2 0 117.8 9.8 92 90 SZ 145 01/13/12 E of Building Pad 7 343 2 0 117.0 9.2 91 90 146 01/18/12 Building Pad I 336 2 0 119.1 9.8 93 90 147 01/18/12 BuiIding Pad 3 336 1 0 109.9 12.1 92 90 148 . 01/19/12 Between Building Pads 7 & 8 338 2 0 116.1 11.2 91 90 149 01/19/1 2 Between Building Pads 5 & 6 338 1 0 108.1 12.4 90 90 FG 150 01/20/12 Building Pad 12 338 2 0 115.9 9.8 91 90 FG 151 01/20/12 Building Pads 9to II 339 2 0 118.5 9.4 93 90 FG 152 01/20/12 Building Pads 9 t Il 339 2 0 119.7 9.7 94 90 FG 153 01/20/12 Building Pads 21 to 23 329 2 . 0 . 116.1 9.4 91 90 FG 154 01/20/12 Building ['ads 21 to 23 329 2 0 118.3 9.8 92 90 155 01/20/12 NE of Building Pad 19 325 2 0 115.7 9.5 90 90 156 01/20/12 Building Pad 20 326 2 0 118.7 9.2 93 90 157 01/23/12 Between 13uildiiig Pads 13 & 14 328 2 0 117.1 9.0 92 90 158 01/23/12 Between Building Pads 14& 15 326 .2 0 115.8 9.8 91 90 159 01/23/12 E of Buildig Pad IS . 326 2 0 117.3 10.9 92 90 ST 160 01/23/12 EofBuilding Pad 2 346 2 0 116.3 11.1 91 . ? ST 161 01/23/12 E of Building Pad 342 2 0 123.2 10.7 96 90 ST 162 01/23/12 BLlilcling Pad 7 347 2 0 117.6 10.9 . 92 90 ST 163 01/23/12 Wof Building Pad 12 335 2 0 115.8 9.8 91 90 ST 164 01/23/12 Building Pad 334 I 0 111.1 14.2 93 90 ST 165 01/23/12 Building Pad 14 336 1 0 111.1 12.8 93 90 166 01/27/12 Between Building Pads 23 & 24 333 2 0 118.4 10.2 93 90 FG 167 01/27/12 'N of Building Pad 3 337 2 0 120.0 10.1 94 90 FG 168 01/27/1 2 Between Building Pads I & 2 337 2 0 119.3 12.0 93 90 FO 169 01/27/12 Building Pad 4 339 2 0 117.2 10.8 92 90 FG 170 01/27/12 Building Pads 6 & 7 339 2 0 116.1 10.7 91 90 FO 171 01/27/12 Building Pad 8 339 2 0 118.2 10.8 92 90 FG 172 01/27/12 Building Pads 19 & 20 327 2 0 116.3 10.9 91 90 FG 173 01/27/12 Building Pad 13 329 2 0 116.1 12.1 91 90 FG 174 02/13/12 Building Pad 340 2 0 119.5 9.5 93 90 FG 175 02/13/12 Building Pads 25 & 26 336 I 0 110.0 12.4 92 90 FG . 176 02/13/12 Building Pad 29 . 337 2 0 115.9 9.0 91 90 17CP 177 02/13/12 Building Pad 3l 337 2 0 117.7 9.8 92 90 Project No. 07671-52-02 June 7. 2012 TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Elev. or Depth (It) Curve No. Plus 3/4" Rock (°) Field Dry Dens. (pci) Field Moist. Cont. (%) Field Rd. Comp. (%) Req'd. Rd. Comp. (%) 329 2 0 120.7 10.6 94 90 327 2 0 121.4 11.2 95 90 327 2 0 118.4 9.8 93 90 327 2 0 118.3 9.3 92 90 327 2 0 120.0 9.8 94 90 327 2 0 119.9 10.7 94 90 327 2 0 117.4 9.6 92 90 327 2 0 117.7 10.4 92 90 329 2 0 119.5 9.4 93 90 June 7, 2012 Test No. Date Location 178 05/24/12 Building Pad 13 179 05/24/12 Building Pad 16 180 05/24/12 Building Pad IS FG 181 05/25/12 Building Pad IS FG 182 05125/12 Building Pad 17 FG 183 05/25/12 Building Pad 16 FG 184 05/25/12 Building Pad 15 FG 185 05/25/12 BuUding Pad 14 86 05/25/12 Building Pad 13 Project No. 07671-52-02 I I I I I I S I I S I I I TABLE I EXPLANATION OF CODED TERMS - TEST SUFFIX A, B, C, . . . : Retest of previous density test failure, following moisture conditioning and/or recompaction. Fill in area of density test failure was removed and replaced with properly compacted fill soil - PREFIX CODE DESIGNATION FOR TEST NUMBERS FG - FINISH GRADE ST - SLOPE TEST SZ - SLOPE ZONE - CURVE NO. Corresponds to curve numbers listed in the summary of laboratory maximum dry density and optimum moisture content test results table for selected fill soil samples encountered during testing and observation. - ROCK CORRECTION For density tests with rock percentage greater than zero, laboratory maximum dry density and optimum moisture content were adjusted for rock content. For tests with rock content equal to zero, laboratory. maximum dry density and optimum moisture content values are unadjusted. -TYPE OF TEST SC: Sand Cone Test (ASTM D 1 556) NU: Nuclear Density Test (ASTM D6938) OT: Other - ELEVATION/DEPTH Test elevations/depths have been rounded to the nearest whole foot. - LOCATION DESCRIPTION (IP): Indicates in-place tests. Where (I P) appears in the location description, the compaction procedures were not observed by a representative of Geocon. Tests were taken at the surface or in test pits after placement of the fill. The results of these tests are indicative of the relative compaction at the location of the test only and may not be extrapolated to adjacent areas. Geocon has no opinion regarding the relative compaction of fill in adjacent areas. Project No. 07671.52.02 June 7, 2012 TABLE II SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Sample No. Description Maximum Dry Density (pet) Optimum Moisture Content (% dry weight) 1 Dark brown, Silty, fine to medium SAND 119.9 12.0 2 Brown, Silty, fine to medium SAND 127.9 9.0 TABLE III SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Building Pad Nos. Sample No. Moisture Content (°") Dry Density (pd) Expansion Index Soil Expansion Classification Before Test After Test I through 3 El-l1 8.7 15.1 115.0 5 Very Low 4 through 8 EI-I2 8.9 15.3 114.2 2 Very Low 9 through 11 El-8 8.8 15.9 113.4 5 Very Low 12 El-7 9.8 19.7 109.0 17 Very Low 13 El-14 8.7 15.3 115.4 0 Very Low 14 through 18 EI-13 8.9 14.8 115.2 7 Very Low 19 through 20 El-10 8.4 16.1 115.1 0 Very Low 21 through 23 El-9 9.0 16.9 112.6 2 Very Low 24 through 27 El-4 8.4 16.9 114.4 1 Very Low 28 and 29 El-3 8.7 15.5 114.3 4 Very Low 30 through 32 EI-6 8.3 16.8 114.4 13 Very Low 33 and 34 EI-2 7.7 13.1 119.6 1 Very Low 35 through 37 El-I 8.6 16.8 114.0 2 Very Low Project No. 07671-52-02 June 7, 2012 TABLE IV SUMMARY OF WATER SOLUBLE SULFATE LABORATORY TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Water Soluble Sulfate (%) Sulfate Exposure El-i 0.039 Negligible EI-2 - 0.025 Negligible EI-3. 0.037 Negligible EI-4 0.031 Negligible EI6 0.023 Negligible EI-7 0.051 Negligible EI-8 0.033 Negligible EI-9 0.032 Negligible EI-10 0.031 Negligible El-Il 0.032 Negligible EI-12 0.035 Negligible EI-13 0.036 Negligible. 131- 14 0.035 . Negligible Project No. 07671-52-02 June 7, 2012 TABLE V SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS MUROYA PROPERTY; BUILDING PADS I THROUGH 37 Building Pad No. Pad Condition Approximate Maximum Differential Fill Thickness (feet) Approximate Maximum Depth of Fill (feet) Expansion Index Recommended Foundation Category Undercut 1 3 5 2 Undercut 0 3 5 3 Undercut 0 3 5 4 Undercut 0 6 2 5 Undercut 0 4 2 6 Undercut 0 3 2 7 Undercut 0 4 2 8 Undercut 0 4 2 Undercut Due to 0 Cut/FillTransition 4 5 10 Fill I 5 , '5 II Fill I 5 5 12 Fill I 6 17 13 Undercut 3 6 0 14 Undercut I 5 7 IS Undercut 1 5 7 16 Undercut 0 4 7 1 Undercut Due to 5 Cut/Fill Transition 9 7 18 Fill 17 22 7 11 19 Undercut 1 5 0 20 Undercut I 5 0 21 ' Undercut I 5' 2 22 Undercut 2 6 2 23 Undercut' 0 4 2 24 Fill 16, 21 I Project No. 07671-52-02 June 7. 2012 Approximate Approximate Building Pad Condition Maximum Differential Maximum Expansion Recommended Foundation Pad No. Fill Thickness Depth of Fill Index Category (feet) (feet) 25 Fill 14 '19 1 II 26 Fill 15 18 1 II 27 Undercut Due to 2 7 1 I CutfFill_Transition 28 Undercut Due to 0 4 4 I Cut/Fill_Transition 29 Fill 7 11 4 ' I 30 , Undercut 1 4 13 I 31 Undercut 1 4 13 I 32 Undercut Due to 2 5 13 I Cut/Fill_Transition 33 Undercut Due to 0 4 1 I Cut/Fill_Transition 34 , Undercut Due to 0 4 ' 1 I' Cut/Fill_Transition 35 Fill 12 22 2 II 36 Fill 14 24 2 II 37 Fill 14 24 2 II TABLE VI SUMMARY OF 2010 CBC SITE CLASS MUROYA PROPERTY Lot Nos. 2010 CBC Soil Profile Type 1 through 23 ' C 24 25 through 34 C 35 through 37 D Project No. 07671-52-02 June 7, 2012 INTERIM REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURINGSITE GRADING MUROYA PROPERTY BUILDINGS I THROUGH 12 AND 19 THROUGH 37 CARLSBAD, CALIFORNIA / PREPARED FOR TAYLOR W000ROW HOMES INCORPORATED IRVINE, CALIFORNIA FEBRUARY 13, 2012 - PROJECT NO. 07671-52-02 GEOCON INCORPORATED GEOTECHNICAL •ENVIRONMENTA1. MAT E R I A L S (07) Project No. 07671-52-02 February 13, 2012 Taylor Woodrow Homes Incorporated 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Attention: Mr. Torn Baiiie Subject: INTERIM REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING MUROYA PROPERTY BUILDINGS I THROUGH 12 AND 19 THROUGH 37 CARLSBAD, CALIFORNIA Dear Mr. Baine: In accordance with your request and our Proposal No. (LG-I 1175) dated June 20, 2011, we have provided testing and observation services during grading operations for the subject development. The grading operations for the subject lots have been completed and is the subject of this report. Building Pads 13 through 18 are currently used to stockpile excess soil generated from on-site construction. We will prepare a final report of testing and observation services upon completion of finish grading operations for Building Pads 13 through 18. We performed our services during the period of November 30, 2011 through January 27, 2012. The scope of our services summarized in this report includes: Observing the grading operations, including the removal and/or processing of topsoil, colluvium, and alluvium and the undercutting lots to expose formational Very Old Paralic Deposits. Observing removal excavations during remedial grading operations, performing field mapping, and providing geotechnical engineering consultation services. Performing in-place density tests on fill soil placed and compacted at the site. Performing laboratory tests to aid in evaluating the maximum dry density and optimum moisture content of. the compacted fill. Additionally, we performed laboratory tests on samples of soil present within approximately 3 feet of finish grade to evaluate expansion characteristics and water-soluble sulfate content. Preparing an Interim As-Graded Geologic Map. . Preparing this interim report of grading 6960 Flanders Drive • San Diego, California 92121-2974 U Telephone 858.558.6900 • Fax 858.558.6159 GENERAL The purpose of this report is to document that the grading for Building Pads 1 through 12 and 19 through 37 within the Muroya Property has been performed in substantial conformance with the recommendations of the project geotechnical report and that fill materials have been properly placed and compacted. We will prepare a final grading report for the development'When the finish grading is completed for Building Pads 13 through 18. The Muroya Property development is located on the west side of Black Rail Road and south of Corte Orchidia in Carlsbad, California (see Vicinity Map, Figure. 1). The grading contractor for the project was Reed Thomas Company inc. of Santa Ana, California. We used an electronic version of the grading plans, provided by Pangaea Land Consultants, as the base map for our interim As-Graded Geologic Map (Figure 2, map pocket). To aid in preparation of this report.we reviewed: Geotechnical Investigation, Muroya Property, Carlsbad, California, prepared by Geocon Incorporated, dated July 14, 2009 (Project No. 07671-52-01). 2. Grading Plans for'.- Muroya, prepared by Pangaea Land Consiltants, Inc., dated October 19, 2011, Drawing No. 471-7A (Project No. CT 06-27). References to elevations and locations herein were based on surveyor's or grade checker's stakes in the field and interpolation from the referenced grading plans. Geocon Incorporated did not provide surveying services and, therefore, has no opinion regarding the accuracy of the elevations or surface geometry with respect to the approved plans GRADING Grading began with the removal of existing structures, utilities, brush, and vegetation from the area to be graded. Following these removals, topsoil, alluvium, colluvium, and undocumented fill were removed for re-use as fill materials. The exposed formational Very Old Paralic Deposits were then scarified, moisture conditioned as necessary, and compacted, prior to receiving fill. Grading consisted of removals varying from 3 to 10 feet to expose the Very Old Paralic Deposits and placing fill thicknesses varying from 3 to approximately 24 feet. The subject building pads are underlain by compacted fill overlying the Very Old Paralic Deposits (formerly described as Lindavista Formation). Undercutting operations were performed within planned cut areas for building pads and roadways. Fill materials derived from onsite excavations were placed and compacted in layers until the design elevations were attained. Lots with cut-fill transitions exposed at grade were undercut a minimum of 3 feet and replaced with properly compacted fill. in general, on-site fill Project No. 07671-52-02 -2- February 13, 2012 materials consist of silty, fine to medium sand. Fill soil was moisture conditioned as necessary, mixed during placement, and compacted using conventional heavy-duty grading equipment. Due to undercutting operations performed for Verdura Walls No. 8 and 14 (Building Pads 17 through 18, and 35 through 37, respectively), the maximum differential fill thickness for building pads located adjacent to these walls are approximately 5 to 14 feet. In conjunction with the construction of Verdura Wall No. 8, a maximum fill soil of approximately 5 to 11 feet was placed within Building Pads 17 and 18 to achieve finish pad grade elevations ranging from 327 to 328 feet above Mean Sea Level (MSL). In conjunction with the construction of Verdura Wall No. 14, a maximum fill soil thickness of approximately 22 to 24 feet was placed within Building Pads 35 through 37 (model building pads) to achieve finish pad gradeelevations ranging from 338 to 339 feet MSL. During grading operations, we observed compaction procedures and performed in-place density tests to evaluate the dry density and moisture content of the fill materials. In conjunction with the grading operations, we also provided testing and observation services during the construction of Verdura Walls No. 8 and 14. We performed the in-place density tests in general conformance with ASTM Test Method D 6938 (nuclear). The results of the in-place dry density and moisture content tests are summarized on Table I. In general, the in-place test results indicate the fill soil has a dry density of least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content at the locations tested. The approximate locations of the in-place density tests are shown on the Interim As-Graded Geologic Map, Figure 2. Table I includes in-place density and moisture content test results performed during the construction of the Vendura Walls and the overall grading of the development. We selected laboratory tests on samples of material used for fill to evaluate moisture-density relationships from mass grading operations. In addition, we obtained samples used for fill to evaluate expansion potential (ASTM D 4829) and water-soluble sulfate content (California Test No. 417). The results of the laboratory tests are summarized on Tables Ii through IV. During the grading operations, excess soil was generated and stockpiled on Building Pads 13 through 18. We did not performed in-place density and moisture content tests at finish pad grade elevation. Once the stockpile material is removed from these pads, we will perform additional testing and observation services to the finish grade pad elevations and prepare a final report of grading. SLOPES The project slopes within the planned development consisted of cut and fill slopes constructed at inclinations of 2:1 and 1.5:1 (horizontal: vertical), respectively, or flatter with maximum heights of approximately 10 feet and 55 feet, respectively. We observed the finished cut slopes once the design inclinations were achieved. Slopes should be planted, drained, and maintained to reduce erosion. Project No. 07671-52-02 . -3- February 13, 2012 Slope irrigation should be kept to a minimum to just support the vegetative cover. Surface drainage should not be allowed to flow over the top of slopes. Prior to grading, the debris fill encountered within the planned fill slopes were removed and replaced with compacted fill. Portions of the debris fill remained outside the limits of grading due to the encroachment into sensitive habitat. The remedial grading operations within the slope area located west of Building Pads 35 through 37 (west of Verdura Wall No. 14) was subject to deep removals in order to establish a 1:1 inclination into formational materials. The retaining wall was founded in formational Very Old Paralic Deposits. Debris fill exists on the surface of the descending slope below Wall 14 as shown on Figure 2. The proposed 1 /2:1 (horizontal:vertical) fill slope located southwest of Building Pads 23 through 28 was constructed by removing the existing debris fill material and establishing a backcut in dense formational materials. Once the adequate backcut was constructed, a 15-foot-wide keyway was excavated to the removal bottom elevation and a heel drain system was installed at the base of the excavation. In general, fill slopes were either over-filled and cut back or track-walked with a bulldozer during grading. Fill materials derived from onsite excavations were placed and compacted in layers until the design elevations were attained. Geogrid was placed during the construction of the I V2:1 (horizontal: vertical) fill slope located southwest of building pads 23 through 28. The grid consisted of Strata Grid 200 and was placed with a vertical spacing of approximately 3 feet and was placed 10 feet horizontally from the face of slope. SUBDRAINS The contractor installed a canyon subdrain at the approximate location shown on the As-Graded Geologic Map (Figure 2). In addition, the subdrain was "as-built" for location and elevation by the project civil engineer. During grading operations, this subdrain was tied-into the existing emergency overflow spillway/dissipato.r at the base of the fill slope. The subdrain consists of a 6-inch diameter PVC, Schedule 40, perforated pipe placed in crushed aggregate surrounded by Mirafi 140N filter fabric. The subdrain was placed at least .10 feet below finish grade and constructed at a flow gradient of at least 1 percent. The grading contractor also installed a heel drain system within the keyway of the 1V2:l (horizontal: vertical) fill slope below Building Pads 23 through 28. The heel drain system was constructed with a. 6-inch-diameter PVC, Schedule 40, perforated pipe placed in crushed aggregate surrounded by Mirafi 140N filter fabric. The subdrain extends along the back of the 15-foot-wide keyway with a solid pipe extending out into the open space of the existing canyon drainage at the mid-point of the drain. The subdrain pipe was capped on both ends and was constructed to have a Project No. 07671-52-02 -4- February 13, 2012 flow gradient towards the mid-point connection. A concrete cutoff will was constructed at the connection point with the solid pipe. The subdrains should be maintained regularly to prevent sediment and debris from obstructing the free flowof water of the subdrain system. A concrete headwall should be constructed at the subdrain outlet in open space. SOIL AND GEOLOGIC CONDITIONS The soil and geologic conditions encountered during grading are similar to those described in the project geotechnical report. Undercutting of the lots and the placement of compacted fill (Qcf and Quc) were performed in accordance with recommendations provided in the project geotechnical report. The Interim As-Graded Geologic Map, Figure. 2, depicts the general geologic conditions observed. Table V ID presents a summary of the as-graded building pad conditions for the subject lots. The subject pads are underlain by compacted fill ranging in thickness between about 3 to 24 feet overlying formational Very Old Paralic Deposits (formerly named the Lindavista Formation). In general, the compacted fill consist of silty, fine to medium sand CONCLUSIONS AND RECOMMENDATIONS 1.0 General 1.1 Based on our observations and test results, it is the opinion of Geocon Incorporated that the grading to which this report pertains has been performed in general conformance with the recommendations of the previously referenced project geotechnical report and the geotechnicàl requirements of the grading plans. 1.2 We did not observe soil or geologic conditions during grading that would preclude the continued development of the property as planned. Based on laboratory test results and field observations, it is the opinion of Geocon Incorporated the fill observed and tested as part of the grading for this project was generally compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. 1.3 The site is underlain by compacted fill and Very Old Paralic Deposits. We observed the placement of compacted fill during grading operations and performed in-place density tests to evaluate the dry density and moisture content of the fill material. 1.4 Laboratory testing of near-grade soil conditions indicates that the upper approximately 3 feet of soil underlying the subject pads possess a "non-expansive" and "very low" Project No. 07671-52-02 - 5 - February 13, 2012 expansion potential. (expansion index [El] of 20 or less). In addition, the samples indicate the soil possesses "negligible" water-soluble sulfate content. 1.5 The site is considered suitable for the use of conventional foundations with slabs-oil-grade, and/or post-tensioned foundation systems. Foundation categories for the subject building pads are presented in Table V. 1.6 Excavations within the fill and the Very Old Paralic Deposits should generally be possible with moderate to heavy effort using conventional heavy-duty equipment. Excavations for utility trenches within formational materials may encounter localized cemented zones that will require very heavy effort to excavate and oversize blocks may be generated. 2.0 Finish Grade Soil Conditions 2.1 Observations and laboratory test results indicate that the prevailing soil conditions within the upper approximately 3 feet of finish grade for the subject building pads is considered'to be "non-expansive" (expansion index [El] of 20 or less) as defined by 2010 California Building Code (CBC) Section 1803.53. Table 2 presents soil classifications based on the expansion index. Results of the El laboratory tests are presented in Table III and indicate that the soil possesses "very low" expansion potentials (El of 20 or less). TABLE 2 SOIL CLASSIFICATION, BASED ON EXPANSION INDEX Expansion Index (El) Soil Classification 0-20 Very Low 21-50 , Low 51 -90 Medium 91-130 . High Greater Than 130 Very High 2.2 We performed laboratory tests on samples of the site materials for the subject building pads to evaluate the percentage of water-soluble sulfate content. Results from the laboratory water-soluble sulfate content tests are presented in Table IV and indicate that the on-site materials at the locations tested possess "negligible" sulfate exposure to concrete structures as defined by 2010 CBC Section 1904.3 and ACI 318-08 Sections 4.2 and 4.3. The presence of water-soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from the site could yield different concentrations. Additionally, over Project No. 07671-52-02 .-6- February 13, 2012 time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. - 2.3 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, further evaluation by a corrosion engineer may be performed if improvements that could be susceptible to corrosion are planned. 3.0 Seismic Design Criteria 3. 1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the USGS. Table 3 summarizes site-specific design criteria obtained from the 2010 California Building Code (CBC; Based on the 2009 International Building Code [IBC]), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. The planned buildings and improvements can be designed using a Site Class C where the fill soil beneath building pads is less than 20 feet or Site Class D for building pads with a fill thickness greater than 20 feet. We evaluated the site class in accordance with Section 1613.5.5 of the 2010 CBC. Table VI presents the recommended Site Class for the subject lots. TABLE 3 2010 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2010 CBC Reference Site Class C D Table 16 13.5.2 Fill Thickness, T (feet) T20 T>20 -- Spectral Response — Class B (short), Ss 1.218g 1.218g Figure 1613.5(3) Spectral Response—Class B(1 sec), S 0.459g 0.459g Figure 1613.5(4) Site Coefficient, Fa 1.000 1.013 Table 1613.5.3(1) Site Coefficient F, 1.341 1.541 Table 1613.5.3(2) Maximum Considered Earthquake Spectral Response Acceleration (short), S4s 1.218g 1 1.2341; Section 1613.5.3 (Eqn 16-36) Maximum Considered Earthquake Spectral Response Acceleration —(1 sec), Sm I 0.616g 0.708g Section 16 13.5.3 (Eqn 16-37) 5% Damped Design Spectral Response Acceleration (short), Ss 0.812g 0.823g Section 1613.5.4 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (1_sec),_ SDI 0 411° i 0.472g Section 1613.5.4 (Eqn 16-39) 3.2 Conformance to the criteria in Table 3 for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if Project No. 07671-52-02 -7- February 13, 2012 a maximum level earthquake occurs. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive. 4.0 Foundation and Concrete Slabs-On-Grade Recommendations 4.1 The foundation recommendations herein are for proposed one- to three-story residential structures. The foundation recommendations have been separated into three categories based on either the maximum and differential fill thickness or Expansion Index. The foundation category criteria are presented in Table 4.1. TABLE 4.1 FOUNDATION CATEGORY CRITERIA Foundation Category Maximum Fill Thickness, T (Feet) Differential Fill Thickness, D (Feet) Expansion Index (El) T<20 -- El<50 II 20<T<50 1O<D<20 50<El<90 Ill T>50 D>20 90<Ei<I30 4.2 Table 4.2 presents minimum foundation and interior concrete slab design criteria for conventional foundation systems. TABLE 4.2 CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Minimum Footing Embedment Depth. Continuous Footing Interior Slab Category (inches) Reinforcement Reinforcement 12 Two No.4 bars, 6 x 6- 10/10 welded wire one top and one bottom mesh at slab mid-point 11 18 Four No. 4 bars, No. 3 bars at 24 inches two top and two bottom on center, both directions III 24 Four No. 5 bars, No. 3 bars at 18 inches two top and two bottom on center, both directions 4.3 The embedment depths presented in Table 4.2 should be measured from the lowest adjacent pad grade for both interior and exterior footings. The conventional foundations should have a minimum width of 12 inches and 24 inches for continuous and isolated footings, respectively. Figure 3 presents a wall/column footingdimension detail. Project No. 07671-52-02 -8- February 13, 2012 4.4 The concrete slab-on-grade should be a minimum of 4 inches thick for Foundation Categories I and 11 and 5 inches thick for Foundation Category III. 4.5 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture- sensitive materials should be underlain by a vapor retarder. The vapor retarder design should be consistent with the guidelines presented in the American Concrete Institute's (ACI) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06). In addition, the membrane should be installed in accordance with manufacturer's recommendations and ASTM requirements and installed in a manner that prevents puncture. The vapor retarder used should be specified by the project architect or developer based on the type of floor covering that will be installed and if the structure will possess a humidity- controlled environment. 4.6 Placement of I to 2 inches of sand is common practice in Southern California. The foundation engineer (the post-tensioned design engineer) should provide appropriate concrete mix design criteria and curing measures that may be utilized to assure proper curing of the slab to reduce the potential for rapid moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation engineer present concrete mix design and proper curing methods on the foundation plans. It is critical that the foundation contractor understands and follows the recommendations presented on the foundation plans. 4.7 As an alternative to the conventional foundation recommendations, consideration should be given to the use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The post-tensioned systems should be designed by a structural engineer experienced in post-tensioned slab design and design criteria of the Post- Tensioning Institute (PTI), Third Edition, as required by the 2010 California Building Code (CBC Section 1808.6). Although this procedure was developed for expansive soil conditions, it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post-tensioned design should incorporate the geotechnical parameters presented on Table 4.3 for the particular Foundation Category designated. The parameters presented in Table 4.3 are based on the guidelines presented in the PTI, Third Edition design manual. Project No. 07671-52-02 -9- February 13, 2012 TABLE 4.3 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS Post-Tensioning Institute (PTI) Third Edition Design Parameters Foundation Category 1 ii iii Thornthwaite Index -20 -20 -20 Equilibrium Suction 3.9 3.9 . 3.9 Edge Lift Moisture Variation Distance, e 1 (feet) 5.3 5.1 4.9 Edge Lift, YM (inches) 0.61 1.10 1.58 Center Lift Moisture Variation Distance, e 1 (feet) 9.0 9.0 9.0 Center Lift, Yt (inches) 0.30 0.47 0.66 4.8 Foundation systems for the building pads that possess a foundation Category I and a "very low" expansion potential (expansion inde of 20 or Ies) can be designed using the method described in Section 1808 of the 2010 CBC. If post-tensioned foundations are planned, an alternative, commonly accepted design method (other than PTI Third Edition) can be used. However, the post-tensioned foundation system should be designed with a total and differential deflection of 1 inch. Geocon Incorporated should be contacted to review the plans and provide additional information, if necessary. 4.9 The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. If a post-tensioned mat foundation system is, planned, the slab should possess a thickened edge with aminimum width of 12 inches and extend below the clean sand or crushed rock layer. 4.10 If the structural engineer proposes a post-tensioned foundation design method other than PTI, Third Edition: The deflection criteria presented in Table 4.3 are still applicable. Interior stiffener beams should be used for Foundation Categories 11 and III. . The width of the perimeter foundations should be at least 12 inches. The perimeter footing embedment depths should be at least 12 inches, 18 inches and 24 inches for foundation categories I, II, and III, respectively. The embedment depths should be measured from the lowest adjacent pad grade. 4.11 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift, regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI design procedures primarily address the potential center lift of slabs but, because of the Project No. 07671-52-02 10 - . February 13, 2012 placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after tensioning reduces the ability of the system to mitigate edge lift. The structural engineer Should design the foundation system to reduce the potential of edge lift occurring for the proposed structures. 4.12 During the construction of the post-tension foundation system, the concrete should be placed monolithically. Under no circumstances should cold joints form between the footings/grade beams and the slab during the construction of the post-tension foundation system. 4.13 Category 1, 11, or III foundations may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be increased by one-third for transient loads due to wind or seismic forces. 4.14 Isolated footings, if present, should have the minimum embedment depth and width recommended for conventional foundations for a particular foundation category. The use of isolated footings, which are located beyond the perimeter of the building and support structural elements connected to the building, are not recommended for Category III. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams. 4.15 For Foundation Category Ill, consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to reduce the potential for future separation to occur. 4.16 Foundation excavations should be observed by the geotechnical engineer (a representative of Geocon Incorporated) prior to the placement of reinforcing steel to check that the exposed soil conditions are similar tothose expected and that they have been extended to the appropriate bearing strata. If unexpected soil conditions are encountered, foundation modifications may be required. 4.17 Special subgrade presaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisture conditioned,, as necessary, to maintain a moist condition as would be expected in such concrete placement. Project No. 07671-52-02 - II - February 13, 2012 4.18 Where buildings or other improvements are planned near the top of a slope steeper than 3:1 (horizontal:vertical), special foundations and/or design considerations are recommended due to the tendency for lateral soil movement to occur. . For fill slopes less than 20 feet high, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the foundations should be extended to a depth where the minimum horizontal distance is equal to H/3 (where H equals the vertical distance from the top of the fill slope to the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The horizontal distance is measured from the outer, deepest edge of the footing to the face of the slope. An acceptable alternative to deepening the footings would be the use of a post-tensioned slab and foundation system or increased footing and slab reinforcement. Specific design parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined. If a swimming pool is proposed, Geocon Incorporated should be contacted to review the plans and the specific site conditions to provide additional recommendations, if necessary. Swimming pools located within 7 feet of the top of cut or fill slopes are not recommended. Where such a condition cannot be avoided, the portion of the swimming pool wall within 7 feet of the slope face be designed assuming that the adjacent soil provides no lateral support. This recommendation applies to fill slopes up to 30 feet in height, and cut slopes regardless of height. For swimming pools located near the top of fill slopes greater than 30 fe& in height, additional recommendations may be required and Geocon Incorporated should be contacted for a review of specific site conditions. Although other improvements, which are relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures that would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. 4.19 The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soil (if present), differential settlement of existing soil or soil with varying thicknesses. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper ProectNo. 07671-52-02 - 12- . February 13, 2012 concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. 4.20 . Exterior concrete flatwork not subject to vehicular traffic should be constructed in accordance with the recommendations herein. Slab panels should be a minimum of 4 inches thick and, when in excess of 8 feet • square, should be reinforced with 6 x 6 - W2.9/W2.9 (6 x 6 - 6/6) welded wire mesh placed in the middle of the slab to reduce the potential for cracking. In addition, concrete flatwork should be provided with crack control joints to reduce and/or control shrinkage cracking. Crack control spacing Should be determined by the project structural engineer based on the slab thickness and intended usage. Criteria of the American Concrete Institute (ACI) should be taken into consideration when establishing crack control spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted in accordance with criteria presented in the grading section prior to concrete placement. Subgrade soil should be properly compacted and the moisture content of subgrade soil should be checked prior to placing concrete. Base or sand bedding is not required beneath the flatwork. 4.21 Even with the inorporation of the recommendations within this report, exterior concrete flatwork has a potential of experiencing some movement due to swelling or settlement; therefore, welded wire mesh should overlap continuously in flatwork. Additionally, flatwork should be structurally connected to curbs, where possible. 4.22. Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. . 5.0 Retaining Walls and Lateral Loads 5.1 Retaining walls not restrained at the top and having a level backfill surface should be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2:1 (horizontal: vertical), an active soil pressure of 50 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1:1 plane extending upward from the base of the wall possess an expansion index of 50 or less. For those buildings with finish-grade soils having an expansion index greater than 50 and/or where backfill materials do not conform to the criteria herein, Geocon Incorporated should be consulted for additional recommendations. . 5.2 Unrestrained walls are those that are allowed to rotate more than 0.00IH (where H equals the height of the retaining portion of the wall) at the top of the wall. Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf should be Project No. 07671-52-02 - 13- February 13, 2012 added to the above active soil pressure. For retaining walls subject to vehicular loads within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to 2 feet of fill soil should be added. 5.3 Retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and waterproofed as required by the project architect. The use of drainage openings through the base of the wall (weep holes) is not recommended where the seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of the wall. The above recommendations assume a properly compacted free-draining backfill material (El of 50 or less) with no hydrostatic forces or imposed surcharge load. Figure 4 presents a typicalretaining wall drainage detail. If conditions different than those described are expected, or if specific drainage details are desired, Geocon Incorporated Should be contacted for additional recommendations. 5.4 In general, wall foundations founded in properly compacted fill or formational materials should possess a minimum depth and width of one foot and may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within three feet below the base of'the wall has an expansion index of 90 or less. The proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where such a condition is expected. 5.5 The structural engineer should determine the seismic design category for the project in accordance with Section 1613 of the 2010 CBC. If the project possesses a seismic design category of D, E, or F, the proposed retaining walls should be designed with seismic lateral pressures. The seismic load exerted on the wall should be a triangular distribution with a pressure of 25H (where H is the height of the wall, in feet, resulting ill pounds per square foot [psf]) exerted at the base of the wall and zero at the top of the wall. We used a peak site acceleration of 0.33g calculated from Section 1803.5.12 of the.2010 California Building Code (S0 /2.5) and applying a pseudo-static coefficient of 0.5. 5.6 Footings that must be placed within seven feet of the top of slopes should be extended in depth such that the outer bottom edge of the footing is at least seven feet 'horizontally inside the face of the slope. 5.7 To resist lateral loads, a passive pressure exerted by ail equivalent fluid weight of 350 pounds per cubic foot (pcf) should be used for the design of footings or shear keys poured neat in compacted fill. The passive pressure assumes a horizontal surface extending at least 5 feet, or three times the surface generating the passive pressure, whichever is Project No. 07671-52-02 - 14- February 13, 2012 greater. The upper 12 inches of material in areas not protected by floor slabs or pavement should not be included in design for passive resistance. 5.8 If friction is to be used to resist lateral loads, an allowable coefficient of friction between soil and concrete of 0.4 should be used for design. 59 The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or other types of walls are planned, such as crib-type walls, Geocon Incorporated should be consulted for additional recommendations. 6.0 Mechanically Stabilized Earth (MSE) Retaining Walls 6.1 MSE retaining walls are alternative walls that consist of modular block facing units with geogrid-reinforced earth behind the block The geogrid attaches to the block units and is typically placed at specified vertical intervals and embedment lengths. Spacing and lengths are based on the type and strength characteristics of soil used for the backfill. MSE walls Should be designed for any surcharge loads due to ascending fill slopes or building loads as deemed necessary by the structural engineer and wall designer. 6.2 Based on inforrnationobtained from the referenced geotechnical investigation report, the geotechnical parameters provided in Table 6 can be used for design of the MSE walls. TABLE 6 GEOTECHNICAL PARAMETERS FOR GEOSYNTHETIC REINFORCED WALLS Parameter Reinforced Zone Retained Zone Foundation Zone Angle of Internal Friction 30 degrees 30 degrees 30 degrees Cohesion 300 psf 300 psf 300 psf Wet Unit Weight 130 pcf 130 pcf 130 pcf 6.3 The soil parameters presented in Table I are based on our experience and direct shear- strength tests performed during the geotechnical investigation and previous grading operations and represent some of the on-site materials. The wet unit weight values' presented in Table I can be used for design but actual in-place densities may range from approximately 110 to 145 pounds per cubic foot. Geocon Incorporated has no way of knowing whether these materials will actually be used as backfill behind the wall during construction. It is up to the wall designers to use their judgment in selection of the design parameters. As such, once backfill materials have been selected and/or stockpiled, Project No. 07671-52-02 - 15 February 13, 2012 sufficient shear tests should be conducted on samples of the proposed backfill materials to check that they conform to actual design values. Results should be provided to the designer to re-evaluate stability of the walls. Dependent upon test results, the designer may require modifications to the original wall design (e.g., longer reinforcement embedment lengths). 6.4 For walls founded on and retaining compacted fill, the angle of internal friction recommended for the reinforced zone should also be used for the retained zone and foundation zone. The foundation zone is the area where the footing is embedded, the reinforced zone is the area of the backfill that possesses the reinforcing fabric, and the retained zone is the area.behind the reinforced zone. 6.5 An allowable soil bearing pressure of 2,000 psf (pounds per square foot) should be used for foundation design and calculations for wall bearing. This bearing pressure assumes a minimum foundation width and depth of 12 inches founded in compacted fill or formational materials. The allowable soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil bearing pressure of 4,000 psf. 6.6 Backfill materials within the reinforced zone should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557-02. This is applicable to the entire embedment width of the geogrid reinforcement. Typically, wall designers specify no heavy compaction equipment within 3 feet of the face of the wall. However, smaller equipment (e.g., walk-behind, self-driven compactors or hand whackers) can be used to compact the materials without 'causing deformation of the wall. If the designer specifies no compactive effort for this zone, the materials are essentially not properly compacted and the geogrid within the uncompacted zone should not be relied upon for reinforcement, and overall embedment lengths will have to be increased to account for the difference. 6.7 The wall should be provided with a drainage system sufficient to prevent excessive seepage through the wall and the base, of the wall, thus preventing hydrostatic pressures behind the wall. 6.8 Geosynthetic reinforcement must elongate to develop full tensile resistance. This elongation generally results in movement at the top of the wall. The amount of movement is dependent upon the height of the wall (e.g., higher walls rotate more) and the type of geogrid reinforcing used. In addition, over time geogrid has been known to exhibit creep (sometimes as much as 5 percent) and can undergo additional movement. Given this Project No. 07671-52-02 -16- February 13, 2012 condition, the owner should be aware that structures and pavement placed within the reinforced and retained zones of the wall may undergo movement. 7.0 Slope Maintenance 7.1 Slopes that are steeper than 3:1 (horizontal: vertical) may, under conditions which are both difficult to prevent and predict, be susceptible to near surface (surficial) slope instability. The instability is typically limited to the outer three feet of a portion of the slope and usually does not directly impact the improvements on the pad areas above or below the slope. The occurrence of surficial instability is more prevalent on fill slopes and is generally preceded by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage. The disturbance and/or loosening of the surficial soils, as might result from root growth, soil expansion, or excavation for irrigation lines and slope planting, may also be a significant contributing factor to surficial instability. It is, therefore, recommended that, to the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or properly recompacted, (b) irrigation systems be periodically inspected and maintained to eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be periodically maintained to preclude ponding or erosion. It should be noted that although the incorporation of the above recommendations shpuld reduce the potential for surficial slope instability, it will not eliminate the possibility, and, therefore, it may be necessary to rebuild or repair a portion of the project's slopes in the future. 8.0 Site Drainage 8.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed away, from structures in accordance with 2010 CBC 1804.3 .or other applicable standards. In addition, surface drainage should be directed away from the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. 8.2 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks for early detection of water infiltration and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for a prolonged period of time. 8.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for surface or irrigation water to infiltrate the pavement's subgrade and base course. We recommend that drains to collect excess irrigation water and transmit it to drainage Project No. 07671-52-02 -17- February 13, 2012 structures, or impervious above-grade planter boxes be used. In addition, where landscaping is planned adjacent to the pavement, we recommended construction of a cutoff wall along the edge of the pavement that extends at least 6 inches below the bottom of the base material. 8.4 If detention basins, bioswales, retention basins, water infiltration or low impact development (LID) devices are being considered, Geocon Incorporated should be retained to provide recommendations pertaining to the geotechnical aspects of possible impacts and design. Distress may be caused to planned improvements and properties located hydrologically downstream. The distress depends on the amount of water to be detained, its residence time, soil permeability, and other factors. We have not performed a hydrogeology study at the site. Downstream properties may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other impacts as a result of water infiltration. 8.5 Based on previous calculated infiltration rates, the existing soil may not be conducive to water infiltration. In addition, basins that are located adjacent to the planned structures and where distress could occur from infiltration, the storm water management devices should be properly constructed to prevent water infiltration. The planned retention basin areas Should be lined with an impermeable liner (e.g. High-density polyethylene, HDPE, with a thickness of about 12 mil or equivalent Polyvinyl Chloride, PVC, liner). 8.6 We do not expect water will infiltrate the fill or formational materials within the paver pavement areas. The paver areas should be setback from the planned structures at least 5 feet. However, the subgrade should be graded to allow water to flow to a subdrain. The subdrain should be placed at the bottom of the base section along the low point of the driveway to reduce the potential for water to build up within the paving section. The drain should be connected to a drainage device as determined by the project civil engineer. Impermeable liners located below the paver section will not be required if the payers are installed as recommended herein. The drain should consist of a 3-inch diameter perforated Schedule 40, PVC pipe wrapped in filter fabric and placed adjacent to the concrete band. LIMITATIONS The conclusions and recommendations contained herein apply only to our work with respect to grading, and represent conditions at the date of our latest observation on January 27, 2012. Any subsequent grading should be done in conjunction with our observation and testing services. As used herein, the term "observation" implies only that we observed the progress of the work with which we agreed to be involved. Our services.did not include the evaluation or identification of the potential presence of hazardous or corrosive materials. Our conclusions and opinions as to whether the work Project No. 07671-52-02 - 18- . February 13, 2012 essentially complies with the job specifications are based on our observations; experience, and test results. . Subsurface conditions, and the accuracy of tests used to measure such conditions, can vary greatly at any time. We make no warranty, express or implied, except that our services were performed in accordance with engineering principles generally accepted at this time and location. We will accept no responsibility for any subsequent changes made to the site by others, by the uncontrolled action of water, or by the failure of others to properly repair damages caused by the uncontrolled action of water. The findings and recommendations of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and Should not be relied upon after a period of three years. If you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Cristian Shawn Foy Weedon Senior Staff Engineer GE 2714 CAL:SFW:JH:dmc Hoobs C G 1524 (2/del) Addressee oFESS 2( No.2714 Exp.06/30/13 OF CAO~ ) JOHN HOOBS No. i524 CERTIFIED ENGINEERING. GEOLOGIST NOp CA-'!>' Project No. 07671-52-02 - 19- February 13, 2012 FIG. 1 CONCRETE SLAB .A . :....-:.•....... PAD GRADE SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI ' . ....... .< " 00 LL FOOTING WIDTH 4 4 4 / N SAND AND VAPOR I 4 RETARDER IN ACCORDANCE WITH ACt 4 A 00 / LL FOOTING WIDTH *....SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION NO SCALE I I WALL / COLUMN FOOTING DIMENSION DETAIL I GEOCON 40PINCORPORATED GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974 PHONE 858 558-6900 - FAX 858 558-6159 MUROYA PROPERTY BUILDINGS 1 THROUGH 12 AND 19 THROUGH 37 CARLSBAD, CALIFORNIA CL! RA DSKIGTYPD II DATE 02- 10- 2012 I PROJECT NO. 07671 -52-02 I FIG. 3 COLFOOTZDWG Y:\PROJECTS\07671-52-02 MUROVA PR0PERTY\0ETAILS\C0LF00T2.dwg GROUND SURFACE CONCRETE BROWDCH PROPOSED 1 RETAINING WALL PROPERLY - COMPACTED TEMPORARY BACKCUT BACKFILL PER OSHA MIRAFI 140N FILTER FABRIC 2/3 H (OR EQUIVALENT) -. OPEN GRADED GROUND SURFACE —\ - ", .: 1" MAX. AGGREGATE FOOTING 4" 01k PERFORATED SCHEDULE L-1 I Nt— 40 PVC PIPE EXTENDED TO APPROVED OUTLET 12" — GROUND SURFACE CONCRETE BROWDITCH RETAINING-. WATER PROOFING WALL Jff.- PER ARCHITECT DRAINAGE PANEL (MIRADRAIN 6000 OR EQUIVALENT) 2/3H 3/4" CRUSHED ROCK U (1 CU.FT.IFT.) — FILTER FABRIC ENVELOPE MIRAFI 140N OR EQUIVALENT PROPOSED GRADE 4' DIA. SCHEDULE 40 PERFORATED PVC PIPE OR APPROVED TOTAL DRAIN EXTENDED TO APPROVED OUTLET FOOTING / NOTE: DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING NO SCALE TYPICAL RETAINING WALL DRAIN DETAIL I' GEOCON INCORPORATED (OP - GEOTECHNICAL • ENVIRONMENTAL • MATERIALS. 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 CL! IRA DSKIGTYPD MUROYA PROPERTY BUILDINGS 1 THROUGH 12 AND 19 THROUGH 37 CARLSBAD, CALIFORNIA DATE 02-10- 2012 PROJECT NO. 07671 -52-02 FIG. 4 Y:\PROJECTS107671-52-02 MUROYA PROPERTY\DETAILS\RET WALL DRAIN DETAILS-2.dWg TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location Elev. or Depth Curve No. Plus 3/4 Rock (%) Field Dry Dens. Field Moist. Cont. (pcf) Field Rel. Comp. Reqd. Rd. Comp. SZ I 11/30/11 NofBuildingPad35 324 2 0 118.1 10.2 92 90 2 11/30/11 Building Pad 35 325 2 0 120.0 9.8 94 90 3 12/01/11 WofBuildingPad37 324 2 0 120.0 11.1 94 90 4 12/01/11 E of Building Pad 35 330 1 0 109.9 12.9 92 90 5 12/01/I1 NofBui1dingPad35 331 1 0 110.1 12.3 92 90 6 12/01/I1 E of Building Pad 36 328 2 0 116.7 10.6 91 90 7 12/01/11 Sweetclover Lane 15+30 332 2 0 116.1 10.8 91 90 8 12/01/11 Building Pad 36 331 2 0 114.4 8.7 89 90 8A 12/01/11 Building Pad 36 . 331 2 0 116.0 10.1 91 90 9 12/02/11 Building Pad 35 335 2 0 114.9 11.7 90 90 10 12/02/11 Building Pad 37 337 2 0 115.2 10.4 90 90 11 12/02/11 SofBuildingPad34 332 2 0 116.4 10.1 91 90 • 12 12/02/11 W of Building Pad 34 329 2 0 115.0 11.7 90 90 13 12/05/11 Sweetclover Lane 12+40 332 2 0 121.0 9.5 95 90 • 14 12/05/11 SW of Building Pad 34 330 2 0 118.3 9.8 92 90 15 12/05/11 Building Pad 33 333 2 0 120.1 9.3 94 90 16 12/05/11 SE of Building Pad 34 336 2 0 116.1 9.4 91 90 17 12/05/11 SE.ofBuilding Pad 34 337 2 0 116.6 9.1 91 90 18 12/06/11 SE of Building Pad 29 331 2 0 122.1 9.0 95 90 19 12/06/11 NW of Building Pad 29 332 2 0 115.7 10.6 90 90 20 12/06/11 SW of Building Pad 26 333 2 0 116.7 9.9 91 90 21 12/06/11 NW ofBuilding Pad 26 334 2 0 116.0 9.4 91 90 22 12/07/11 Building Pad 24 332 2 0 115.4 10.0 90 90 23 12/07/11 Building Pad 26 335 1 0 108.6 14.1 91 90 24 12/07/11 NE of Building Pad 24 332 2 0 115.2 10.2 90 90 25 12/07/11 NE of Building Pad 25 334 2 0 117.0 9.3 91 90 SZ 26 12/08/11 Wall 8 Basin 303 2 0 118.2 9.2 92 90 27 12/08/11 Wall 8 Basin 305 2 0 115.9 9.3 91 90 SZ 28 12/08/11 Wall 8 Basin 308 2 0 117.1 9.0 92 90 29 12/08/11 Wall 8 Basin 309 2 0 115.2 9.4 90 90 30 12/09/11 Wall Basin 310 2 0 120.1 11.6 94 90 SZ 31 12/09/11 Wall8Basin 313 2 0 116.5 12.5 91 90 32 12/09/11 Wall 8Basin 314 2 0 117.4 11.7 92 90 33 12/09/11 Wall Basin 315 2 0 117.7 10.1 92 90 34 - 12/09/11 Building Pad 18 315 2 0 115.0 12.0 90 90 35 12/09/11 Wall 8Basin 316 2 0 115.8 10.4 91 90 36 12/14/11 S of Building Pad 12 335 1 0 109.0 14.2 91 90 37 12/14/11 S of Building Pad 9 337 1 0 107.7 15.9 90 • 90 SZ 38 12/14/I1 Wall 8Basin 317 2 0 115.1 11.4 90 90 SZ 39 12/14/11 Wall 8 Basin 318 2 0 116.4 10.9 91 90 SZ 40 12/15/11 Wall 8 Basin 320 1 0 107.8 13.2 90 90. SZ 41 12/15/11 Wall 8 Basin 320 I 0 108.6 13.1 91 90 SZ 42 12/15/11 Wall 8Basin 321 2 0 116.6 10.2 91 90 43 12/15/11 Building Pad 18 322 I 0 109.0 13.1 91 90 44 12/15/1I W of Building Pad 17 321 2 0 115.4 9.7 90 90 Project No. 07671-52-02 . February 13, 2012 TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location Elev. or Depth (ft) Curve No. Plus 3/4 Rock (%) Field Dry Dens. (pci) Field Moist. Cont. (%) Field Rel. Comp. (%) Req'd. Re!. Comp. (%) 45 12/16/1I W of Building Pad 18 323 I 0 107.9 13.1 90 90 46 12/16/I1 S of Building Pad 17 325 1 0 108.7 13.4 91 90 SZ 47 12/16/1I Wall 8 Basin 324 2 0 118.1 9.4 92 90 SZ 48 12/16/I1 Wall 8 Basin 321 2 0 115.9 9.9 91 90 SZ 49 12/16/11 Wall 8 Basin 324 2 0 117.2 9.0 92 90 50 12/19/11 W of Building Pad 35 328 1 0 107.8 15.2 90 90 SZ 51 12/19/11 SW ofBuilding Pad 37 327 1 0 110.4 14.4 92 90 SZ 52 12/19/11 NW of Building Pad 35 331 1 0 108.2 12.1 90 90 SZ 53 12/19/11 W of Building Pad 36 330 2 0 115.6 11.4 90 90 SZ 54 12/20/11 W of Building Pad 35 334 2 0 116.2 10.4 91 90 SZ 55 12/20/11 W of Building Pad 37 333 2 0 112.7 7.5 88 90 SZ 55A 12/20/I1 WofBuildingPad37 333 2 0 114.9 10.8 90 90 56 12/20/I1 NW of Building Pad 36 336 1 0 111.0 12.5 93 90 57 12/21/I1 Building Pad 35 . 337 I 0 108.8 13.1 91 90 58 12/21/I1 Building Pad 37 338 1 0 109.2 12.8 91 90 59 12/21/I1 NW of Building Pad 12 337 2 0 119.0 9.6 93 90 60 12/21/1I Building Pad 9 338 2 0 115.8 11.0 91 90 61 12/22/11 Building Pad 21 327 2 0 117.0 9.9 91 90 62 12/22/I1 NE of Building Pad 23 328 2 0 115.4 11.2 90 90 63 12/22/1I Building Pad 27 334 2 0 118.3 11.9 92 90 64 12/22/I1 EofBuilding Pad 28 335 1 0 108.7 14.1 91 90 SZ 65 12/23/11 SW of Building Pad 25; Keyway 286 1 0 107.6 12.0 90 90 SZ 66 12/23/11 SW of Building Pad 25; Keyway . 289 1 0 107.5 13.9 90 90 SZ 67 12/27/11 SW of Building Pad 25; Keyway 293 2 0 115.7 10.5 90 90 SZ 68 12/27/11 SW of Building Pad 25; Keyway 296 2 . 0 116.0 11.0 91 90 SZ 69 12/27/1I SW of Building Pad 25; Keyway 298 2 0 117.2 11.7 92 90 SZ 70 12/27/11 SW of Building Pad 24; Keyway 301 2 0 118.0 11.2 92 90 SZ 71 12/27/11 SW of Building Pad 25; Keyway 303 2 0 116.7 10.5 91 90 SZ 72 12/27/11 SW of Building Pad 24; Keyway 303 2 0 116.5 11.8 91 90 SZ 73 12/28/11 SW of Building Pad 26; Keyway 305 1 0 109.0 14.6 91 90 SZ 74 12/28/11 SW of Building Pad 25 305 1 0 109.8 12.4 92 90 ST 75 12/28/11 Wall 8 Basin 317 1 0 111.8 12.8 93 90 ST 76 12/28/1I Wall 8 Basin 320 2 0 117.4 11.2 92 90 SZ 77 12/28/11 SW of Building Pad 24 308 2 0 117.9 10.1 92 90 SZ 78 12/28/11 SW of Building Pad 26 308 1 0 108.5 12.6 90 90 SZ 79 12/28/11 SW of Building Pad 27 311 2 0 115.8 11.0 91 90 SZ 80 .12/28/11 SW of Building Pad 24 311 I 0 112.0 13.2 93 90 SZ 81 12/28/I1 SW of Building Pad 25 314 2 0 115.6 10.8 90 90 SZ 82 12/28/I1 SW of Building Pad 26 314 2 0 115.8 10.1 91 90 83 12/29/1I S of Building Pad 15 325 1 0 107.7 14.3 90 90 84 12/29/11 Building Pad 14 326 2 0 118.6 11.0 93 90 85 12/29/11 W of Building Pad 15 325 2 0 116.9 10.3 91 90 86 12/29/11 SE of Building Pad 18 326 2 0 119.4 9.4 93 90 ST 87 12/30/1I SW of Building Pad 26 313 1 0 107.9 12.6 90 90 ST 88 12/30/11 SW of Building Pad 24 309 2 0 116.6 11.0 91 90 Project No. 07671-52-02 February 13. 2012 TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location 89 12/30/11 Building Pad l6 90 12/30/11 W of Building Pad 13 SZ 91 12/30/11 SW of Building Pad 24 SZ 92 12/30/1I SW of Building Pad 25 SZ 93 12/30/11 SW of Building Pad 27 SZ 94 01/03/12 SW of Building Pad 26 SZ 95 01/03/12 SW of Building Pad 24 SZ 95 A 01/03/12 SW of Building Pad 24 SZ 96 01/03/12 SW of Building Pad 25 SZ 97 0 1/03/12 SW of Building Pad 29 SZ 98 01/03/12 SW of Building Pad 29 SZ 99 01/04/12 S ofBuilding Pad 29 SZ 100 01/04/12 SW of Building Pad 27 101 01/04/12 SW of Building Pad 24 SZ 102 01/04/12 NofBuilding Pad 15 SZ 103 01/04/12 Eof Building Pad l4 ST 104 01/04/12 W of Building Pad 37 ST 105 01/04/12 Nof Building Pad 35 FG 106 01/04/12 Building Pad 35 FG 107 01/04/12 Building Pads 36 & 37 SZ 108 01/04/12 SW of Building Pad 26 SZ 109 01/04/12 SW of Building Pad 29 SZ 110 01/05/12 SW of Building Pad 27 111 01/05/12. SW of Building Pad 24 SZ 112 01/05/12 SofBuildingPad29 SZ 113 ----------------------------------------------------------------------------- 01/05/12 SW of Building Pad 25 SZ 114 01/05/12 SW of Building Pad 29 115 01/05/12 Building Pad 25 SZ 116 01/05/12 S of Building Pad 29 SZ 117 01/05/12 S of Building Pad 29 SZ 118 01/05/12 NofBuilding Pad 14 SZ 119 01/05/12 E of Building Pad 13 120 01/06/12 Building Pad 3l 121 01/06/12 N of Building Pad 32 ST 122' 01/09/12 SW of Building Pad 24 ST 123 01/09/12 SW of Building Pad 26 SZ 124 01/09/12 NofBuilding Pad 30 SZ 1,25 01/09/12 N of Building Pad 30 FG 126 01/10/12 Building Pad 28 FO 127 01/-I-0/1-2--E-of Building Pad 27 FG 128 01/10/12 E of Building Pad 24 ST 129 01/10/12 SW of Building Pad 27 ST 130 01/10/12 sw of Building Pad 29 ST 131 01/10/12 SW of Building Pad29 SZ 132 01/10/12 SofBuilding Pad I Elev. Plus Field Field Field Reqd. or 3/4 Dry Moist. Rel. Rel. Depth Curve Rock Dens. Cont. Comp. Comp. (ft) No. (%) (pcfl (%) (%) (%) 2 0 115.6 12.0 90 90 2 0 117.3 11.5 92 90 1 0. 108.1 13.1 90 90 1 0 108.1 13.8 90 90 1 0 109.8 14.2 92 90 1 0 109.8 12.0 92 90 1 0 106.0 9.4 88 90 1 0 108.4 12.5 90 90 1 0 111.4 14.1 93 90 1 0 111.6 12.2 93 90 I 0 109.8 13.4 92 90 2 0 115.9 11.9 91 90 2 0 117.5 10.3 92 90 1 0 108.4 12.5 90 90 1 0 109.0 12.1 91 90 1 0 108.5 -------------------------------------------------------------------- 13.0 90 90 2 0 115.8 9.5 91 90 2 0 115.9 10.2 91 90 2 0 116.7 11.1 91 90 2 0 117.5 9.1 92 90 2 0 121.1 12.0 95 90 2 0 119.3 11.1 93 90 2 0 115.9 10.1 91 90 2 0 117.5 10.5 92 90 2 0 116.9 11.0. 91 90 2 0 115.8 12.4 91 , 90 2 0 119.2 11.7 93 90 2 0 116.2 11.4 91 90 1 0 110.4 15.3 92 90 2 0 117.0 10.9 91 90 2 '0 117.7 10.1 92 90 2 0 115.9 11.0 91 90 2 0 116.1 11.2 91 90 2 0 115.7 11.9 90 90 2 0 116.8 9.4 91 90 2 0 118.1 9.0 92 90 2 0 116.8 9.5 91 90 2 0 120.1 9.2 94 90 2 0 118.4 9.7 93 90 2 0 120.0 9.6 94 90 2 0 124.8 -------------------------------------------------------------------- 9.3 98 90 1 0 111.8 12.7 93 90 2 0 115.9 9.9 91 90 2 0 116.4 11.7 91 90 2 0 119.7 10.1 94 90 326 328 317 317 317 ---------------- 319 320 320 323 317 ---------------- 320. 322 325 326 331 ---------------- 332 330 335 338 339 ------------ 328 324 331 331 325 ---------------- 333 328 335 331 328 ---------------- 334 335 335 336 321 329 337 339 337 336 ---------------- 336 325 320 330 338 Project No. 07671-52-02 . February 13, 2012 Elev. Plus Field Field Field Req'd. or 3/4 Dry Moist. Rel. Rel. Depth Curve Rock Dens. Cont. Comp. Comp. (ft) No. (%) (pcf) (%) (%) (%) 339 2 0 115.7 9.7 90 333 2 0 117.4 9.5 92 332 2 0 117.7 10.0 92 334 2 O• 121.3 9.0 95 337 2 0 116.2 11.7 91 337 2 0 117.1 9.3 92 337 2 0 116.7 10.7 91 340 2 0 115.9 9.9 91 341 1 0 108.7 14.9 91 343 2 0 116.0 9.9 91 341 2 ----------------------------------------------------------------- 0 115.9 10.2 91 345 2 0 117.8 9.8 92 343 2 0 117.0 9.2 91 336 2 0 119.1 9.8 93 336 I 0 109.9 12.1 92 338 2 ----------------------------------------------------------------- 0 116.1 11.2 91 338 1 0 108.1 12.4 90 338 2 0 115.9 9.8 91 339 2 0 118.5 9.4 93 339 2 0 119.7 9.7 94 329 2 0 116.1 9.4 .91 329 2 0 118.3 9.8 92 325 2 0 115.7 9.5 90 326 2 0 118.7 9.2 93 328 2 0 117.1 9.0 92 326 2 0 115.8 9.8 91 326 2 0 117.3 10.9 92 346 2 0 116.3 11.1 91 342 2 0 123.2 10.7 96 347 2 0 117.6 10.9 92 335 2 0 115.8 9.8 91 334 1 0 111.1 14.2 93 336 1 0 111.1 12:8 93 333 2 0 118.4 10.2 93 337 2 0 - 120.0 10.194 337 2 0 119.3 12.0 93. 339 2 0 117.2 10.8 92 339 2 0 116.1 10.7 91 339 2 0 118.2 10.8 92 327 2 0 116.3 10.9 91--- 329 2 0 116.1 12.1 91 340 2 0 119.5 9.5 93 336 1 0, 110.0 12.4 92 337 2 0 115.9 9.0 91 337 2 0 117.7 9.8 92 90 90 90 90 90 --------------- 90 90 90 90 90 --------------------- 90 90 90 90 90 --------------- 90 90 90 90 90 ---------------------- 90 90 90 90 90 ---------------- 90 90 90 90 90 ---------------------- 90 90 90 90 90 ---------------------- 90 - 90 90 90 90 -------------------- 90 90 90 90 90 TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location 133 01/10/12 N of Building Pad 30; White Sage Wa FG 134 01/11/12 S of Building Pad 29 FG 135 01/11/12 SE of Building Pad 29 FG 136 01/11/12 Building Pads 33 & 34 FG 137 01/11/12 BuildingPad32 FG 138 01/11/12 Building Pad 30 SZ 139 01/11/12 Eof Building Pad 14 SZ 140 01/12/12 E of Building Pad 5 SZ 141 01/12/12 E ofBuilding Pad 35 142 01/12/12 SE of Building Pad I SZ 143 01/12/12 N of Building Pad 4 SZ 144 01/13/12 EofBuilding Pad I SZ 145 01/13/12 EofBuiIdingPad7 146 01/18/12 Building Pad I 147 01/18/12 BuiIdingPad3 148 01/19/12 Between Building Pads 7 & 8 149 01/19/12 Between Building Pads 5 & 6 FG 150 01/20/12 Building Pad 12 FG 151 01/20/12 Building Pads 9 to 11 FG 152 01/20/12 Building Pads 9to 11 FG 153 --------------------------------------------------------------------------------- 01/20/12 Building Pads 21 to 23 FG 154 01/20/12 Building Pads 21 to 23 155 01/20/12 NE of Building Pad 19 156 01/20/12 Building Pad 20 157 01/23/12 Between Building Pads 13 & 14 158 01/23/12 Between Building Pads 14 & 15 159 01/23/12 E of Buildig Pad 18 ST 160 01/23/12 E of Building Pad 2 ST 161 01/23/12 E of Building Pad 5 ST 162 01/23/12 Building Pad 7 ST 163 01/23/12 W of Building Pad 12 ST 164 01/23/12 Building Pad 9 ST 165 01/23/12 Building Pad 14 166 01/27/12 Befween Building Pads 23 & 24 FG 167 01/27/12 W of Building Pad 3 FG 168 ---------------------------------------------------------------------------------- 0 1/27/12 Between Building Pads I & 2 FG 169 01/27/12 Building Pad 4 FG 170 01/27/12 Building Pads 6 & 7 FG 171 01/27/12 Building Pad 8 FG 172 01/27/12 Building Pads 19 & 20 FG 173 01/27/12 Buildirg Pad 13 FG 174 02/13/12 Building Pad 5 FG 175 02/13/12 Building Pads 25 & 25 FG 176 02/13/12 Building Pad 29 FG 177 02/13/12 Building Pad 31 Project No. 07671-52-02 . February 13, 2012 TABLE I EXPLANATION OF CODED TERMS -TEST SUFFIX A, B, C,. . . : Retest of previous density test failure, following moisture conditioning and/or recompaction. - STRIKE-OUT Fill in area of density test failure was removed and replaced with properly compacted fill soil. - PREFIX CODE DESIGNATION FOR TEST NUMBERS FG - FINISH GRADE . ST - SLOPE TEST SZ - SLOPE ZONE -CURVENO. Corresponds to curve numbers listed in the summary of laboratory maximum dry density and optimum moisture content test results table for selected fill soil samples encountered during testing and observation. - ROCK CORRECTION For density tests with rock percentage greater than zero, laboratory maximum dry density and optimum moisture content were adjusted for rock content. For tests with rock content equal to zero, laboratory maximum dry density and optimum moisture content values are unadjusted. -TYPE OF TEST SC: Sand Cone Test (ASTM P1556) NU: Nuclear Density Test (ASTM D2922) OT: Other - ELEVATION/DEPTH Test elevations/depths have been rounded to the nearest whole foot. Project No. 07671-52-02 February 13, 2012 TABLE II SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Sample No. Description Maximum Dry Density (pci) Optimum Moisture Content (% dry weight) 1 Dark brown, Silty, fine to medium SAND 119.9 12.0 2 Brown, Silty, fine to medium SAND 127.9 . 9.0 TABLE III SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Building Pad Nos. Sample No. Moisture Content (°') Dry Density (pet) Expansion Index Soil-Expansion Classification Before Test After Test 1 through 3 El-I1 8.7 15.1 115.0 5 Very Low 4 through 8 El- 12 8.9 15.3 114.2 2 Very Low 9 through II EI-8 8.8 15.9 113.4 5 Very Low 12 El-7 9.8 19.7 109.0 17 Very Low 19 through 20 El-10 8.4 16.1 115.1 0 Very Low 21 through 23 El-9 9.0 16.9 112.6 2 Very Low 24 through 27 E14 8.4 16.9 114.4 1 Very Low 28 through 29 El-3 8.7 15.5 114.3 4 Very Low 30 through 32 El-6 8.3 16.8 114.4 13 Very Low 33 through 34 EI-2 7.7 13.1 119.6 1 Very Low 35 through 37 El-l- 8.6 16.8 114.0 2 Very Low TABLE IV SUMMARY OF WATER SOLUBLE SULFATE LABORATORY TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Water Soluble Sulfate (%) Sulfate Exposure El-1 0.039 Negligible El-2 0.025 Negligible El-3 . 0.037 Negligible E14 . 0.031 Negligible El-6 0.023 Negligible E1-7 0.051 Negligible El-8 0.033 • Negligible El-9 0.032 Negligible EI-10 0.031 Negligible El-1 I 0.032 Negligible El-12 0.035 Negligible Project No. 07671-52-02 February 13, 2012 TABLE V SUMMARY-OF AS-GRADED BUILDING PAD CONDITIONS MUROYA PROPERTY; BUILDING PADS I THROUGH 12, AND 19 THROUGH 37 Building Pad No. Pad Condition Approximate Maximum Differential Fill Thickness (feet) Approximate Maximum Depth of Fill (feet) Expansion Index Foundation Recommended Category Undercut -. 1 3 5 1 2 Undercut 0 3 5 1 3 Undercüf 0 3 5 4 Undercut 0 6 2 5 Undercut 0 4 2 6 Undercut 0 3 2 7 Undercut 0 4 2 8 Undercut 0 4 2 Undercut Due to 0 Cut/Fill Transition 4 5 10 Fill 1 5 5 11 Fill 1 5 5 12 Fill I . 6 17 I 19 Undercut I 5 0 20 Undercut I 5 0 21 Undercut 1 5 2 22 Undercut 2 6 2 1 23 Undercut 0 4 2 24 Fill 16 21 1 II 25 Fill 14 19 1 II 26 Fill 15 18 1 II 27 Undercut Due to 2 Cut/Fill Transition 7 1 28 Undercut Due to 0 Cut/Fill Transition 4 4 1 29 Fill 7 11 4 I 30 Undercut 1 4 31 Undercut 1 4 13 1 -, _32 Cut/Fill Undercut Due to Transition 2 5 13 Undercut Due to 0 Cut/Fill Transition 4 1 -, Undercut Due to 0 Cut/Fill Transition 4 1 35 Fill 12 22 2 11 36 Fill 14 . 24 2 11 37 Fill 14 - 24 2 1 II Project No. 07671-52-02 February 13, 2012 TABLE VI SUMMARY OF 2010 CBC SITE CLASS MUROYA PROPERTY Lot Nos. 2010 CBC Soil Profile Type 1 through 12 C 19 through 23 C 24 - D 25 through 34 C 35 through 37 D Project No. 07671-52-02 February 13, 2012 INTERIM REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING MUROYA PROPERTY MODEL LOTS BUILDINGS 35 THROUGA 37 CARLSBAD, CALIFORNIA / PREPARED FOR TAYLOR WOODROW HOMES INCORPORATED IRVINE, CALIFORNIA JANUARY 17, 2012 PROJECT NO. 07671-52-02 GEOCON INCORPORATED GEOTECHNICAL • ENV'IRONMENTAL • M AT E R I A I S (107/F) Project No. 07671-52-02 January 17, 2012 Taylor Woodrow Homes Incorporated 8105 Irvine Center Drive, Suite 1450 Irvine, California 92618 Attention: Mr. Tom Baine Subject: INTERIM REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING MUROYA PROPERTY MODEL LOTS - BUILDINGS 35 THROUGH 37 CARLSBAD, CALIFORNIA Dear Mr. Baine: In accordance with your request and our Proposal No. (LG-11175) dated June 20, 2011, we have provided testing and observation services during grading operations for the model lots - buildings 35 through 37 of the subject development. Grading of the balance of the project is currently in progress. We will prepare a final report of testing and observation services upon completion of grading operations. The grading of the model lots has been completed and is the subject of this report. We performed our services during the period of November 30, 2011 through January 6, 2012. The scope of our services summarized in this report includes: Qsc.ryir!g the grading operations, including the removal and/or processing of topsoil, colluvium, and alluvium and the undercutting lots to expose formational Very Old Paralic Deposits. Observing removal excavations during remedial grading operations, performing field mapping, and providing geotechnical engineering consultation services. Perform' ing in-place density tests on fill soil placed and compacted at the site. Performing laboratory tests to aid in evaluating the maximum dry density and optimum moisture content of the compacted fill. Additionally, we performed laboratory tests on samples of soil present within approximately 3 feet of finish grade to evaluate expansion'. characteristics and water-soluble sulfate content. Preparing an As-Graded Geologic Map. Preparing this interim report of grading. 6960 Flanders Drive 0 San Diego, California 92121-2974 U Telephone 858.558.6900 0 Fax 858.558.6159 GENERAL The purpose of this report is to document that the grading for the model lots - buildings 35 through 37 within the Muroya Property has been performed in substantial conformance with the recommendations of the project geotechnical report and that fill materials have been properly placed and compacted. We will prepare a final grading report for the development when the grading is completed. The Muroya Property development is located on the west side of Black Rail Road and south of Corte Orchidia in Carlsbad, California (see Vicinity Map, Figure 1). The grading contractor for the project was Reed Thomas Company Inc. of Santa Ana, California. We used an electronic version of the grading plans, provided by Pangaea Land Consultants, as the base map for our As-Graded Geologic Map (Figure 2). To aid in preparation of this report we reviewed: Geotechnical Investigation, Muroya Property, Carlsbad, California, prepared by Geocon Incorporated, dated July 14, 2009 (Project No. 07671-52-01). 2. Grading Plans for. Muroya, prepared by Pangaea Land Consultants, Inc., dated October 19, 2011, Drawing No. 471-7A (Project No. CT 06-27). References to elevations and locations herein were based on surveyor's or grade checker's stakes in the field and interpolation from the referenced grading plans. Geocon Incorporated did not provide surveying services and, therefore, has no opinion regarding the accuracy of the elevations or surface geometry with respect to the approved plans. GRADING This report pertains to the grading of building pads 35 through 37 within the Muroya Property development. Grading began with the removal and export of vegetation from the area to be graded. Topsoil, alluvium, colluvium, and undocumented fill were removed for re-use as fill materials. The exposed formational Very Old Paralic Deposits were then scarified, moisture conditioned as necessary, and compacted, prior to receiving fill. Grading consisted of removals varying from 3 to 5 feet to expose the Very Old Paralic Deposits and placing fill varying from 8 to 24 feet. The subject building pads are underlain by compacted fill overlying the Very Old Paralic Deposits (formerly described as Lindavista Formation). The undercutting operations extended laterally within the areas of grading. Due to undercutting operations performed for Vendura Wall No. 14, the maximum differential fill thickness for building pads 35, 36, and 37 is approximately 12 to 14 feet. In conjunction with the construction of Vendura Wall No. 14, a maximum fill soil of approximately 22 to 24 feet was placed within the model building pads to Project No. 07671-52-02 -2- January 17, 2012 achieve finish pad grade elevations ranging from 338 to 339 feet above Mean Sea Level (MSL). Fill materials derived from onsite excavations were placed and compacted in layers until the design elevations were attained. During grading operations, we observed compaction procedures and performed in-place density tests to evaluate the dry density and moisture content of the fill materials. We performed the in-place density tests in general conformance with ASTM Test Method D 6938 (nuclear). The results of the in-place dry density and moisture content tests. are summarized on Table I. In general, the in-place test results indicate the fill soil has a dry density of least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content at the locations tested. The approximate locations of the in-place density tests are shown on the As-Graded Geologic Map, Figure 2. Although this report applies to building pads 35 through 37, Table I includes in-place density and moisture content test results performed during the overall grading of the development. We selected, laboratory tests on samples of material used for fill to evaluate moisture-density relationships from mass grading operations. In addition, we obtained samples used for fill to evaluate expansion potential (ASTM D 4829) and water-soluble sulfate content (California Test No. 417). The results of the laboratory tests are summarized on Tables II through IV. SLOPES The project slopes within the planned development consisted of cut and fill slopes constructed at inclinations.of 2:1 and 1.5:1 (horizontal: vertical) respectively, or flatter with maximum heights of approximately 10 feet and 55 feet, respectively. We observed the finished cut slopes once the design inclinations were achieved. Slopes should be planted, drained, and maintained to reduce erosion. Slope irrigation should be kept to a minimum to just support the vegetative cover. Surface drainage should not be allowed to flow over the top of the slope. The retaining wall located west of the model lots (Wall 14) was founded in formational Very Old Paralic Deposits. Debris fill exists on the surface of the descending slope below Wall 14 as shown on Figure 2. SOIL AND GEOLOGIC CONDITIONS The soil and geologic conditions encountered during grading are similar to those described in the project geotechrncal report. Undercutting of the lots and the placement of compacted fill (Qcf and Quc) were performed in accordance with recommendations provided in the project geotechnical report. The As-Graded Geologic Map, Figure 2, depicts the general geologic conditions observed. Table V presents a summary of the as-graded building pad conditions for the subject lots. The subject pads are underlain by compacted fill ranging in thickness between about 8 to 24 feet overlying formational Very Old Paralic Deposits. In general, the compacted fill consist of silty, fine to medium sand. Project No. 07671-52-02 ._3 - January 17, 2012 CONCLUSIONS AND RECOMMENDATIONS 1.0 General 1.1 Based on our observations and test results, it is the opinion of Geocon Incorporated that the grading to which this report pertains has been performed in general conformance with the recommendations of the previously referenced project geotechnical report and the geotechnical requirements of the grading plans. 1.2 We did not observe soil or geologic conditions during grading that would preclude the continued development of the property as planned. Based on laboratory test results and field observations, it is the opinion of Geocon Incorporated the fill observed and tested as part of the grading for this project was generally compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. 1.3 The site is underlain by compacted fill and Very Old Paralic Deposits. We observed the placement of compacted fill during on-going grading operations and performed in-place density tests to evaluate the dry density and moisture content of the fill material. 1.4 Laboratory testing of near-grade soil conditions indicates that the upper approximately 3 feet of soil underlying the subject pads possess a "very low" expansion potential (expansion index [El] of 20 or less). In addition, the samples indicate the soil possesses "negligible" water-soluble sulfate content. 1.5 The site is considered suitable for the use of conventional foundations with slabs-on-grade, and/or post-tensioned foundation systems. Foundation categories for the subject lots are presented in Table V. 1.6 Excavations within the fill and the Very Old Paralic Deposits should generally be possible with moderate to heavy effort using conventional heavy-duty equipment. Excavations for utility trenches within formational materials may encounter localized cemented zones that will require very heavy effort to excavate and oversize blocks may be generated. 2.0 Finish Grade Soil Conditions 2.1 Observations and laboratory test results indicate that the prevailing soil conditions within the upper approximately 3 feet of finish grade for building pads .35 through 37 is considered to be "non-expansive" (expansion index [El] of 20 or less) as defined by 2010 California Building Code (C.BC) Section 1803.5.3. We will perform additional testing as Project No. 07671-52-02 - -4- 1 1 January 17, 2012 the grading for the other building pads are completed. Table 2 presents soil classifications based on the expansion index. Results of the El laboratory tests are presented in Table III and indicate that the soil possesses "very low" expansion potentials (El of 20 or less). TABLE 2 SOIL CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (El) Soil Classification 0-20 Very Low 21-50 Low 51-90 Medium 91-130 High Greater Than 130 Very High 2.2 We performed laboratory tests on samples of the site materials for the subject building pads to evaluate the percentage of water-soluble sulfate content. Results from the laboratory water-soluble sulfate content tests are presented in Table TV and indicate that the on-site materials at the locations tested possess "negligible" sulfate exposure to concrete structures as defined by 2010 CBC Section 1904.3 and ACI 318-08 Sections 4.2 and 4.3. The presence of water-soluble sulfates is not a visually discernible characteristic;, therefore, other soil samples from the site could yield different concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. 2.3 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, further evaluation by a corrosion engineer may be performed if improvements that could be susceptible to corrosion are planned. 3.0 Seismic Design Criteria 3.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the USGS. Table 3 summarizes site-specific design criteria obtained from the 2010 California Building Code (CBC; Based on the 2009 International Building Code [IBC]), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. The planned buildings and improvements can be designed using a Site Class C where the fill soil is less than 20 feet or D for building pad with fill greater than 20 feet. We evaluated, the site class in accordance with Section 1613.5.5 of the 2010 CBC. Table VI presents the recommended Site Class for the subject lots. Project No. 07671-52-02 -5- January 17, 2012 TABLE 3 2010 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2010 CBC Reference Site Class C D Table 16 13.5.2 Fill Thickness, T (feet) T20 1>20 -- Spectral Response - Class B (short), Ss 1.218g 1.218g Figure 1613.5(3) Spectral Response - Class B (1 see), S 0.459g 0.459g Figure 16 13.5(4) Site Coefficient, Fa 1.000 1.013 Table 1613.5.3(1) Site Coefficient, F 1.341 1.541 Table 1613.5.3(2) Maximum Considered Earthquake Spectral Response Acceleration (short), SMS I .218 1.234g Section 1613.5.3 (Eqn 16-36) Maximum Considered Earthquake Spectral Response Acceleration —(1 see), 5M1 0.616g 0.708g Section 1613.5.3 (Eqn 16-37) 5% Damped Design Spectral Response Acceleration (short), 0.812g 0.823g Section 1613.5.4 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (1 see), 5D1 0.411 g 0.472g Section 1613.5.4 (Eqn 16-39) 3.2 Conformance to the criteria in Table 3 for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if a maximum level earthquake occurs. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive. 4.0 Foundation and Concrete Slabs-On-Grade Recommendations 4.1 The foundation recommendations herein are for proposed one- to three-story residential structures. The foundation recommendations have been separated into three categories based on either the maximum and differential fill thickness or Expansion Index. The foundation category criteria are presented in Table 4.1. TABLE 4.1 FOUNDATION CATEGORY CRITERIA Foundation Category Maximum Fill Thickness, T (Feet) Differential Fill Thickness, D (Feet) Expansion Index (El) 1<20 -- EI<50 II 20<17<50 10<D<20 50<EI<90 III T>50 D>20 . 90<EI<130 Project No. 07671-52-02 - 6 - January 17, 2012 4.2 Table 4.2 presents minimum foundation and interior concrete slab design criteria for conventional foundation systems. TABLE 4.2 CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Minimum Footing Continuous Footing Interior Slab Category Embedment Depth Reinforcement Reinforcement (inches) I 12 Two No. 4 bars, 6 x 6 - 10/10 welded wire one top and one bottom mesh at slab mid-point II 18 Four No. 4 bars, No. 3 bars at 24 inches two top and two bottom on center, both directions III 24 Four No. 5 bars, No. 3 bars at 18 inches two top and two bottom I on center, both directions 4.3 The embedment depths presented in Table 4.2 should be measured from the lowest adjacent pad grade for both interior and exterior footings. The conventional foundations should have a minimum width of 12 inches and 24 inches for continuous and isolated footings, respectively. Figure 3 presents a wall/column footing dimension detail. 4.4 The concrete slab-on-grade should be a minimum of 4 inches thick for Foundation Categories I and II and 5 inches thick for Foundation Category III. 4.5 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture- sensitive materials should be underlain by a vapor retarder. The vapor retarder design should be consistent with the guidelines presented in the American Concrete Institute's (ACT) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACT 302.211-06). In addition, the membrane should be installed in accordance - with manufacturer's recommendations and ASTM requirements and installed in a manner that prevents puncture. The vapor retarder used should be specified by the project architect or developer based on the type of floor covering that will be installed and if the structure will possess a humidity- controlled environment. 4.6 Placement of 1 to 2 inches of sand is common practice in Southern California. The foundation engineer (the post-tensioned design engineer) should provide appropriate concrete mix design criteria and curing measures that may be utilized to assure proper curing of the slab to reduce the potential for rapid moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation engineer present concrete mix design and Project No. 07671-52-02 -7- January 17, 2012 proper curing methods on the foundation plans. It is critical that the foundation contractor understands and follows the recommendations presented on the foundation plans. 4.7 As an alternative to the conventional foundation recommendations, consideration should be given to the. use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The post-tensioned systems should be designed by a structural engineer experienced in post-tensioned slab design and design criteria of the Post- Tensioning Institute (PTI), Third Edition, as required by the 2010 California Building Code (CBC Section 1808.6). Although this procedure was developed for expansive soil conditions, it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post-tensioned design should incorporate the geotechnical parameters presented on Table 4.3 for the particular Foundation Category designated. The parameters presented in Table 4.3 are based on the guidelines presented in the PTI, Third Edition design manual. TABLE 4.3 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS Post-Tensioning Institute (PT!) Third Edition Design Parameters . Foundation Category i ii III Thornthwaite Index -20 -20 -20 Equilibrium Suction 3.9 3.9 3.9 Edge Lift Moisture Variation Distance, em (feet) 5.3 5.1 4.9 Edge Lift, YM (inches) 0.61 1.10 1.58 Center Lift Moisture Variation Distance, em (feet) 9.0 9.0 9.0 Center Lift, YM (inches) 0.30 0.47 0.66 4.8 Foundation systems for the lots that possess a foundation Category I and a "very low" expansion potential (expansion index of 20 or less) can be designed using the method described in Section 1808 of the 2010 CBC. If post-tensioned foundations are planned, an alternative, commonly accepted design method (other than PTI Third Edition) can be used. However, the post-tensioned foundation system should be designed with a total and differential deflection of 1 inch. Geocon Incorporated should be contacted to review the plans and provide additional information, if necessary. 4.9 The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. If a post-tensioned mat foundation system is planned, the slab should possess a thickened edge with a minimum width of 12 inches and extend below the clean sand or crushed rock layer. Project No. 07671-52-02 - 8 - January 17, 2012 4.10 If the structural engineer proposes a post-tensioned foundation design method other than PTI, Third Edition: The deflection criteria presented in Table 4.3 are still applicable. Interior stiffener beams should be used for Foundation Categories II and III. The width of the perimeter foundations should be at least 12 inches. The perimeter footing embedment depths should be at least 12 inches, 18 inches and 24 inches for foundation categories I, II, and III, respectively. The embedment depths should be measured from the lowest adjacent pad grade. 4.11 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift, regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI design procedures primarily address the potential center lift of slabs but, because of the placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after tensioning reduces the ability of the system to mitigate edge lift. The structural engineer should design the foundation system to reduce the potential of edge lift occurring for the proposed structures. 4.12 During the construction of the post-tension foundation system, the concrete should be placed monolithically. Under no circumstances should cold joints form between the footings/grade beams and the slab during the construction of the post-tension foundation system. 4.13 Category I, II, or III foundations may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be increased by one-third for transient loads due to wind or seismic forces. 4.14 Isolated footings, if present, should have the minimum embedment depth and width recommended for conventional foundations for a particular foundation category. The use of isolated footings, which are located beyond the perimeter of the building and support structural elements connected to the building, are not recommended for Category III. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams. . 4.15 For Foundation Category III, consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to reduce the potential for future separation to occur. Project No. 07671-52-02 -9- January 17, 2012 4.16 Foundation excavations should be observed by the geotechnical engineer (a representative of Geocon Incorporated) prior to the placement of reinforcing steel to check that the exposed soil conditions are similar to those expected and that they have been extended to the appropriate bearing strata. If unexpected soil conditions are encountered, foundation modifications may be required. 4.17 Special subgrade presaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary, to maintain a moist condition as would be expected in such concrete placement. 4.18 Where buildings or other improvements are planned near the top of a slope steeper than 3:1 (horizontal: vertical), special foundations and/or design considerations are recommended due to the tendency for lateral soil movement to occur. . For fill slopes less than 20 feet high, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the foundations should be extended to a depth where the minimum horizontal distance is equal to H/3, (where H equals the vertical distance from the top of the fill slope to the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The horizontal distance is measured from the outer, deepest edge of the footing to the face of the slope. An acceptable alternative to deepening the footings would be the use of a post-tensioned slab and foundation system or increased footing and slab reinforcement. Specific design parameters or recommendations for either of these alternatives can be proyided once the building location and fill slope geometry have been determined.. If a swimming pool is proposed, Geocon Incorporated should be contacted to review the plans and the specific site conditions to provide additional recommendations, if necessary. Swimming pools located within 7 feet of the top of cut or fill slopes are not recommended. Where such a condition cannot be avoided, the portion of the swimming pool wall within 7 feet of the slope face be designed assuming that the adjacent soil provides no lateral support. This recommendation applies to fill slopes up to 30 feet in height, and cut slopes regardless of height. For swimming pools located near the top of fill slopes greater than 30 feet in height, additional recommendations may be required and Geocon Incorporated should be contacted for a review of specific site conditions. Although other improvements, which are relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures, that would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. Project No. 07671-52-02 January 17, 2012 4.19. The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soil (if present), differential settlement of existing soil or soil with varying thicknesses. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. 4.20 Exterior concrete flatwork not subject to vehicular traffic should be constructed in accordance with the recommendations herein. Slab panels should be a minimum of 4 inches thick and, when in excess of 8 feet square, should be reinforced with 6 x 6 - W2.9/W2.9 (6 x 6 - 6/6) welded wire mesh placed in the middle of the slab to reduce the potential for cracking. In addition, concrete flatwork should be provided with crack control joints to reduce and/or control shrinkage cracking. Crack control spacing should be determined by the project structural engineer based on the slab thickness and intended usage. Criteria of the American Concrete Institute (ACT) should be taken into consideration when establishing crack control spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted in accordance with criteria presented in the grading section prior to concrete placement. Subgrade soil should be properly compacted and the moisture content of subgrade soil should be checked prior to placing concrete. Base or sand bedding is not required beneath the flatwork. 4.21 Even with the incorporation of the recommendations within this report, exterior concrete flatwork has a potential of experiencing some movement due to swelling or settlement; therefore, welded wire mesh should overlap continuously in flatwork. Additionally, flatwork should be structurally connected to curbs, where possible. . . 4.22 Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. 5.0. Retaining Walls and Lateral Loads 5.1 Retaining walls not restrained at the top and having a level backfill surface should be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of 35 pounds per cubic foot (pcf). Where the backfill will be inclined at no steeper than 2:1 (horizontal: vertical), an active soil pressure of 50 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1:1 plane extending upward from the base of the wall possess an expansion index of 50 or less. For Project No. 07671-52-02 . - 11- January 17, 2012 those buildings with finish-grade soils having an expansion index greater than 50 and/or where backfill materials do not conform to the criteria herein, Geocon Incorporated should be consulted for additional recommendations. 5.2 Unrestrained walls are those that are allowed to rotate more than 0.00IH (where H equals the height of the retaining portion of the wall) at the top of the wall. Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf should be added to the above active soil pressure. For retaining walls subject to vehicular loads within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to 2 feet of fill soil should be added. 5.3 Retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and waterproofed as required by the project architect. The use of drainage openings through the base of the wall (weep holes) is not recommended where the seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of the wall. The above recommendations assume a properly compacted free-draining backfill material (El of 50 or less) with no hydrostatic forces or imposed surcharge load. Figure 4 presents a typical retaining wall drainage detail. If conditions different than those described are expected, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. In general, wall foundations founded in properly compacted fill or formational materials should possess a minimum depth and width of one foot and may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within three feet below the base of the wall has an expansion index of 90 or less. The proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, Geocon Incorporated should be consulted where such a condition is expected. 5.5 The structural engineer should determine the seismic design category for the project in accordance with Section 1613 of the 2010 CBC. If the project possesses a seismic design category of D, E, or F, the proposed retaining walls should be designed with seismic lateral pressures. The seismic load exerted on the wall should be a triangular distribution with a pressure of 25H (where H is the height of the wall, in feet, resulting in pounds per square foot [psf]) exerted at the base of the wall and zero at the top of the wall. We used a peak site acceleration, of 0.33g calculated from Section 1803.5.12 of the 2010 California Building Code (S 5/2.5) and applying a pseudo-static coefficient of 0.5. Project No. 07671-52-02 -12 - January 17, 2012 5.6 Footings that must be placed within seven feet of the top of slopes should be extended in depth such that the outer bottom edge of the footing is at least seven feet horizontally inside the face of the slope. 5.7 To resist lateral loads, a passive pressure exerted by an equivalent fluid weight of 350 pounds per cubic foot (pcf) should be used for the design of footings or shear keys poured neat in compacted fill. The passive pressure assumes a horizontal surface extending at least 5 feet, or three times the surface generating the passive pressure, whichever is greater. The upper 12 inches of material in areas not protected by floor slabs or pavement should not be included in design for passive resistance. 5.8 If friction is to be used to resist lateral loads, an allowable coefficient of friction between soil and concrete of 0.4 should be used for design. 5.9 The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or other types of walls are planned, such as crib-type walls, Geocon Incorporated should be Consulted for additional recommendations. 6.0 Mechanically Stabilized Earth (MSE) Retaining Walls 6.1 MSE retaining walls are alternative walls that consist of modular block, facing units with geogrid-reinforced earth behind the block. The geogrid attaches to the block units and is typically placed at specified vertical intervals and embedment lengths. Spacing and lengths are based on the type and strength characteristics of soil used for the backfill. MSE walls should be designed for any surcharge loads due to ascending fill slopes or building loads as deemed necessary by the structural engineer and wall designer. 6.2 Based on information obtained from the referenced geotechnical investigation report, the geotechnical parameters provided in Table 6 can be used for design of the MSE walls. TABLE 6 GEOTECHNICAL PARAMETERS FOR GEOSYNTHETIC REINFORCED WALLS Parameter Reinforced Zone Retained Zone Foundation Zone Angle of Internal Friction 30 degrees 30 degrees 30 degrees Cohesion 300 psf 300 psf 300 psf Wet Unit Weight 130 pcf 130 pcf 130 pcf Project No. 07671-52-02 -13 - January 17, 2012 6.3 The soil parameters presented in Table I are based on our experience and direct shear- strength tests performed during the geotechnical investigation and previous grading operations and represent some of the on-site materials. The wet unit weight values presented in Table I can be used for design but actual in-place densities may range from approximately 110 to 145 pounds per cubic foot. Geocon Incorporated has no way of knowing whether these materials will actually be used as backfill behind the wall during construction. It is up to the wall designers to use their judgment in selection of the design parameters. As such, once backfill materials have been selected and/or stockpiled, sufficient shear tests should be conducted on samples of the proposed backfill materials to check that they conform to actual design values. Results should be provided to the designer to re-evaluate stability of the walls. Dependent upon test results, the designer may require modifications to the original wall design (e.g., longer reinforcement embedment lengths). 6.4 For walls founded on and retaining compacted fill, the angle of internal friction recommended for the reinforced zone should also be used for the retained zone and foundation zone. The foundation zone is the area where the footing is embedded, the reinforced zone is the area of the backfill that possesses the reinforcing fabric, and the retained zone is the area behind the reinforced zone. 6.5 An allowable soil bearing pressure of 2,000 psf (pounds per square foot) should be used for foundation design and calculations for wall bearing. This bearing pressure assumes a minimum foundation width and depth of 12 inches founded in compacted fill or formational materials. The allowable soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil bearing pressure of 4,000 psf. 6.6 Backfill materials within the reinforced zone should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557-02. This is applicable to the entire embedment width of the geogrid reinforcement. Typically, wall designers specify no heavy compaction equipment within 3 feet of the face of the wall. However, smaller equipment (e.g., walk-behind, self-driven compactors or hand whackers) can be used to compact the materials without causing deformation of the wall. If the designer specifies no compactive effort for this zone, the materials are essentially not properly compacted and the geogrid within the uncompacted zone should not be relied upon for reinforcement, and overall embedment lengths will have to be. increased to account for the difference. Project No. 07671-52-02 -14- January 17, 2012 6.7 The wall should be provided with a drainage system sufficient to prevent excessive seepage through the wall and the base of the wall, thus preventing hydrostatic pressures behind the wall. 6.8 Geosynthetic reinforcement must elongate to develop full tensile resistance. This elongation generally results in movement at the top of the wall. The amount of movement is dependent upon the height of the wall (e.g., higher walls rotate more) and the type of geogrid reinforcing used. In addition, over time geogrid has been known to exhibit creep (sometimes as much as 5 percent) and can undergo additional movement. Given this condition, the owner should be aware that structures and pavement placed within the reinforced and retained zones of the wall may undergo movement. 7.0 Slope Maintenance 7.1 Slopes that are steeper than 3:1 (horizontal: vertical) may, under conditions which are both difficult to prevent and predict, be susceptible to near surface (surficial) slope instability. The instability is typically limited to the outer three feet of a portion of the slope and usually does not directly impact the improvements on the pad areas above or below the slope. The occurrence of surficial instability is more prevalent, on fill slopes and is generally preceded by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage. The disturbance and/or loosening of the surficial soils, as might result from root growth, soil expansion, or excavation for irrigation lines and slope planting, may also be a significant contributing factor to surficial instability. It is, therefore, recommended that, to the maximum extent practical: (a) disturbed/loosened surficial soils be either removed or properly recompacted, (b) irrigation systems be periodically inspected and maintained to eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes.be periodically maintained to preclude ponding or erosion. It should be noted that although the incorporation of the above recommendations should reduce the potential for surficial slope instability, it will not eliminate the possibility, and, therefore, it may be necessary to rebuild or repair a portion of the project's slopes in the future. 8.0 Site Drainage 8.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed awayfrom structures in accordance with 2010 CBC 1804.3 or other applicable standards. In addition, surface drainage should be directed away from the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. Project No. 07671-52-02 - 15- January 17, 2012 8.2 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks for earl' detection of water infiltration and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to 'infiltrate the soil for a prolonged period of time. 8.3 Landscaping planters adjacent to paved areas are tibt recommended due to the potential for surface or irrigation water to infiltrate the pavements subgrade and base course. We recommend that drains to collect excess irrigation water , and transmit it to drainage structures, or impervious above-grade planter boxes be used. In addition,, where landscaping is planned adjacent to the pavement, we recommended construction of a cutoff wall along the edge of the pavement that extends at least 6 inches below the bottom of the base material. 8.4 If detention basins, bioswales, retention basins, water infiltration or low impact development (LID) devices are being considered, Geocon Incorporated should be retained to provide recommendations pertaining to the geotechnical aspects of possible impacts and design. Distress may be caused to planned improvements and properties located hydrologically downstream. The distress depends on the amount of water to be detained, its residence time, soil permeability, and other factors. We have not performed a hydrogeology study at the site. Downstream properties may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other impacts as a result of water infiltration. 8.5 Based on previous calculated infiltration rates, the existing soil may not be conducive to water infiltration. In addition, basins that are located adjacent to the planned structures and where distress could occur from infiltration, the storm water management devices should be properly constructed to prevent water infiltration. The planned retention basin areas should be lined with an impermeable liner (e.g. High-density polyethylene, HDPE, with a thickness of about 12 mil or equivalent Polyvinyl Chloride, PVC, liner). 8.6 We do not expect water will infiltrate the fill or formational materials within the paver pavement areas. The paver areas should be setback from the planned structures at least 5 feet. However, the subgrade should be graded to allow water to flow to a subdrain. The subdrain should be placed at the bottom of the base section along the low point of the driveway to reduce the potential for water to build up within the paving section. The drain should be connected to a drainage device as determined by the project civil engineer. Impermeable liners located below the paver section will not be required if the payers are installed as recommended herein. The drain should consist of a 3-inch diameter perforated Schedule 40, PVC pipe wrapped in filter fabric and placed adjacent to the concrete band. Project No. 07671-52-02 - 16- January 17, 2012 LIMITATIONS The conclusions and recommendations contained herein apply only to our work with respect to grading, and represent conditions at the date of our final observation on January 6, 2011. Any subsequent grading should be done in conjunction with our observation and testing services. As used herein, the term "observation" implies only that we observed the progress of the work with which we agreed to be involved. Our services did not include the evaluation or identification of the potential presence of hazardous or corrosive materials. Our conclusions and opinions as to whether the work essentially complies with the job specifications are based on our observations, experience, and test results. Subsurface conditions, and the accuracy of tests used to measure such conditions, can vary greatly at any time. We make no warranty, express or implied, except that our services were performed in accordance with engineering principles generally accepted at this time and location. We will accept no responsibility for any subsequent changes made to the site by others, by the uncontrolled action of water, or by the failure of others to properly repair damages caused by the uncontrolled action of water. The findings and recommendations of this report may be invalidated wholly or partially by changes outside our control. Therefore, this report is subject to review and should not be relied upon after a period of three years. If you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED tianA.Liang Shawn Foy Weedon Senior Staff Engineer GE 2714 CAL:SFW:JH:dmc (4) Addressee (e-mail) Pangaea Land Consultants Attention: Mr. Dale Mitchell hn Hoobs CEG 1524 (OAL JOHN HOOBS CL No. 1524 CERTIFIED ENGINEERING GEOLOGIST cJ' NOp CALV oF ESS,0'\ NO. 2714 •V 'it Exp.0613o/13cr- OF A )) Project No. 07671-52-02 _17- January 17, 2012 FG.1 S / 0 APPROX. - GRADING LIMITS MUROYA PROPERTY BUILDINGS 35 THROUGH 37 CARLSBAD, CALIFORNIA S S - PAD 334.8 GRAPHIC SCALE 0' 20' 40' 60' 80' SCALE 1"=40' Qmdf GEOCON LEGEND V / GRADING / / LIMITS /-? J VOP 000000 \ ca Qcol Qvo \\_ \QaIJ QvoPj / Tsa K,[Tsa Qcf ........ COMPACTED FILL Qdf ........DEBRIS FILL Qudf ........UNDOCUMENTED FILL Qcol .... Qal ........ALLUVIUM (Dotted Where Buried) QVO ........VERY OLD PARALIC DEPOSITS (Dotted Where Buried) Tsa ........SANTIAGO FORMATION (Dotted Where Buried) FG-1070 LOCATION OF IN-PLACE DENSITY TEST FG .... Finish Grade ST .... Slope Test F-33-1-1 ........ APPROX. ELEVATION AT BASE OF FILL APPROX. LOCATION OF GEOLOGIC CONTACT (Queried Where Uncertain) / 1 IGEOCON / INCORPORATED GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974 PHONE 858 558-6900 - FAX 858 558-6159 PROJECT NO. 07671 -52 - 02 AS - GRADED GEOLOGIC MAP FIGURE 2 DATE 01 - 17-2012 Y:\PR0JECTS1n7671.52.n ItJRflYA PROPERTY\SHEETS\07671.57.07 AS-RD MAP 1Int1.IntmRenort4dwn CONCRETE SLAB . :• A :. . :. - .. PAD GRADE SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI V ..... < Z_ 00 LL \ *•. .... V.-.).. __. . ______ WIDTH CONCRETE SLAB I ...... 4 ...-"':- SAND AND VAPOR RETARDERIN-' fr '- ACCORDANCE WITH ACI 00 U. A A FOOTING WIDTH *SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION NO SCALE I . WALL / COLUMN FOOTING DIMENSION DETAIL I GEOCON INCORPORATED (07)' GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974 PHONE 858 558-6900 - FAX 858 558-6159 MUROYA PROPERTY BUILDINGS 35 THROUGH 37 CARLSBAD, CALIFORNIA CL ' RA DSK/GTYPD DATE 01 - 17-2012 PROJECT NO. 07671 -52 -02 1 FIG-L i IG. 3 COLFOOTZDWG V Y:\PROJECTS\07671-52-02 MUROVA PR0PERTY\0ETAILS\C0LF00T2.dw9 GROUND SURFACE GROUND SURFACE CONCRETE BROWDITCH - PROPOSED RETAINING WALL 2/3 H _H FOOTING TEMPORARY BACKCUT . ' bAUd-I PER OSHA MIR.AFI 140N FILTER FABRIC I (OR EQUIVALENT) OPEN GRADED I 1 MAX. AGGREGATE 4 01k PERFORATED SCHEDULE 40 PVC PIPE EXTENDED TO APPROVED OUTLET 12 GROUND SURFACE CONCRETE BROW ITCH 1 -— RETAINING - WALLJ - 2/3H — 12' PROPOSED — GRADE ,, WATER PROOFING PER ARCHITECT DRAINAGE PANEL (MIRADRAIN 6000 OR EQUIVALENT) 3/4' CRUSHED ROCK (1 CU.FTJFT.) FILTER FABRIC ENVELOPE .-'-'MIRAFI 140N OR EQUIVALENT 7..._ 4' DIA. SCHEDULE 40 PERFORATED PVC PIPE OR APPROVED TOTAL DRAIN EXTENDED TO APPROVED OUTLET NOTE: DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING NO SCALE I TYPICAL RETAINING WALL DRAIN DETAIL . I GEOCON MUROYA PROPERTY INCORPORATED BUILDINGS 35 THROUGH 37 GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121- 2974 CARLSBAD, CALIFORNIA PHONE 858 558-6900 - FAX 858 558-6159 CL ' • DSKJGTYPD DATE 01 - 17-2012 PROJECT NO. 07671 -52-02 FIG. 4 Y:\PROJECTS\07671-52-02 MUROYA PROPERTY\DETAILS\RET WALL DRAIN DETAILS_2.dwg Elev. Plus Field Field Field Req'd. or 3/4 Adj. Adj. Dry Moist. Rel. Rel. Depth Curve Rock MDD OMC Dens. Cont. Comp. Comp. (ft) No. (%) (pet) (%) (pcf) (%) (%) (%) 324 325 324 330 331 --------------------------------------------- 328 332 331 331 335 --------------------------------------------- 337 332 329 332 330 --------------------------------------------- 333 336 337 331 332 --------------------------------------------- 333 334 332 335 332 334 303 305 308 309 --------------------------------------------- 310 2 0 127.9 9.0 118.1 10.2 2 0 127.9 9.0 120.0 9.8 2 0 127.9 9.0 120.0 11.1 1 0 119.9 12.0 109.9 12.9 0 119.9 12.0 110.1 12.3 2 0 127.9 ------------------------------------------------------------------ 9.0 116.7 10.6 2 0 127.9 9.0 116.1 10.8 2 0 127.9 9.0 114.4 8.7 2 0 127.9 9.0 116.0 10.1 2 0 127.9 9.0 114.9 11.7 2 0 127.9 9.0 115.2 10.4 2 0 127.9 9.0 116.4 10.1 2 0 127.9 9.0 115.0 11.7 2 0 127.9 9.0 121.0 9.5 2 0 127.9 9.0 118.3 9.8 2 0 127.9 ------------------------------------------------------------------ 9.0 120.1 9.3 2 0 127.9 9.0 116.1 9.4 2 0 127.9 9.0 116.6 9.1 2 0 127.9 9.0 122.1 9.0 2 0 127.9 9.0 115.7 10.6 2 0 127.9 ------------------------------------------------------------------ 9.0 116.7 9.9 2 0 127.9 9.0 116.0 9.4 2 0 127.9 9.0 115.4 10.0 0 119.9 12.0 108.6 14.1 2 0 127.9 9.0 115.2 10.2 2 0 127.9 9.0 117.0 9.3 2 0 127.9 9.0 118.2 9.2 2 0 • 127.9 9.0 115.9 9.3 2 0 127.9 9.0 117.1 9.0 2 0 127.9 9.0 115.2 9.4 2 0 127.9 9.0 120.1 11.6 92 90 94 90 94 90 92 90 92. 90 91 90 91 90 89 90 91 90 90 90 90 -------------------------------- 90 91 90 90 90 95 90 92 90 94 -------------------------------- 90 91 90 91 90 95 90 90 90 91 -. -------------------------------- 90 91 90 90 90 91 90 90 90 • 91 -------------------------------- 90 92 90 91 90 92 90 90 90 94 -------------------------------- 90 .s.....s..s........i.......s.....i...s.s.... TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location SZ 1 11/30/11 Lot I S of Sweet Clover Lane 2 11/30/11 Lot I S of Sweet Clover Lane 3 12/01/1.1 Lot I S of Sweet Clover Lane 4 12/01/11 Lot I S of Sweet Clover Lane 5 12/01/I1 W of Sweet Clover Lane 6 12/01/11 --------------------------------------------------------------------------------- Lot I S of Sweet Clover Lane 7 12/01/11 Sweet Clover Lane 8 12/01/11 Lot I S of Sweet Clover Lane 8 A 12/01/11 Lot 1 S of Sweet Clover Lane 9 1 2/02/1 1 Lt I S of Sweet Clover Lane 10 12/02/I1 Lot I S of Sweet Clover Lane II 12/02/I1 Lot I E of Sweet Clover Lane 12 12/02/1I Lot I W of Sweet Clover Lane 13 12/05/11 Sweet Clover Lane 14 12/05/1I Lot 1 W of Sweet Clover Lane 15 12/05/11 Lot I E of Sweet Clover Lane 16 12/05/I1 Lot I E of Sweet Clover Lane 17 12/05/11 Lot 1 E of Sweet Clover Lane 18 12/06/11 Lot I W of Sweet Clover Lane 19 12/06/11 Lot I W of Sweet Clover Lane 20 12/06/11 ----------------------------------------------------------------------------- Lot I W of Sweet Clover Lane 21 12/06/11 Lot I W of Sweet Clover Lane 22 12/07/11 Lot I W of Sweet Clover Lane 23 12/07/11 Lot I W of Sweet Clover Lane 24 12/07/11 Lot I White Sage Way 25 12/07/I1 Lot I S of White Sage Way SZ 26 12/08/11 Wall 8 Basin 27 12/08/11 Wall 8 Basin SZ ' 28 12/08/11 Wall 8 Basin 29 12/08/I1 Wall 8 Basin 30 12/09/I1 ---------------------------------------------------------------------------- Wall 8 Basin Project No. 07671-52-02 January 17, 2012 ........................................... TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location Elev. or Depth (ft) Curve No. Plus 3/4 Rock (%) Adj. MDD (pcf) Adj. OMC (%) Field Dry Dens. (pci) Field Moist. Cont. (%) Field Rel. Comp. (%) Req'd. Rd. Comp. (%) SZ 31 12/09/1.1 Wall 8 Basin 313 2 0 127.9 9.0 116.5 12.5 91 90 32 12/09/11 Wall 8 Basin 314 2 0 127.9 9.0 117.4 11.7 92 90 33 12/09/1I Wall 8 Basin 315 2 0 127.9 9.0 117.7 10.1 92 90 34 12/09/I1 Wall 8 Basin 315 2 0 127.9 9.0 115.0 12.0 90 90 35 12/09/I1 Wall 8 Basin 316 2 0 127.9 9.0 115.8 10.4 91 90 36 12/14/11 Lot I W of Holly Leaf Court 335 I 0 119.9. 12.0 109.0 14.2 91 90 37 12/14/I1 Lot I W of Holly Leaf Court 337 I 0 119.9 12.0 107.7 . 15.9 90. 90 SZ 38 12/14/11 Wall 8 Basin 317 2 0 127.9 9.0 115.1 11.4 . 90 90 SZ 39 12/14/I1 Wall 8 Basin 318 2 0 127.9 9.0 116.4 10.9 91 90 SZ 40 12/15/I1 Wall 8 Basin 320 I 0 119.9 12.0 107.8 13.2 90 90 SZ 41 12/15/I1 Wall 8 Basin 320 . 1 0 119.9 12.0 108.6 13.1 91 90 SZ 42 12/15/I1 Wall 8 Basin 321 2 0 127.9 9.0 116.6 10.2 91 90 43 12/15/11 Wall 322 1 0 119.9 12.0 109.0 13.1 91 90 44 12/15/11 Wall 8 321 2 0 127.9 9.0 115.4 9.7 90 90 45 12/16/11 Wall 323 1 0 119.9 12.0 107.9 13.1 .90 90. 46 12/16/11 Wall ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- 325 I 0 119.9 12.0 108.7 13.4 91 90 SZ 47 12/16/I1 Wall 8 Basin . 324 2 0 127.9 9.0 118.1 9.4 92 90 SZ 48 . 12/16/I1 Wall 8 Basin 321 2 0 127.9 9.0 115.9 9.9 91 90 SZ 49 12/16/11 Wall 8 Basin 324 2 0 127.9 9.0 117.2 9.0 92 90 50 12/19/ I'll Lot I S of Sweet Clover Lane 328 I 0 119.9 12.0 107.8 15.2 90 90 SZ 51 12/19/I1 Lot I S of Sweet Clover Lane 327 I 0 119.9 12.0 110.4 14.4 92 90 SZ 52 12/19/I1 Lot I S of Sweet Clover Lane 331 I 0 119.9 12.0 108.2 12.1 90 90 SZ 53 12/19/I1 Lot I S of Sweet Clover Lane 330 2 0 127.9 9.0 115.6 11.4 90 90 SZ 54 12/20/11 Lot I S of Sweet Clover Lane . 334 2 0 127.9 9.0 116.2 10.4 91 90 SZ 55 12/20/11 Lot I S of Sweet Clover Lane 333 2 0 127.9 9.0 112.7 7.5 88 90 SZ 55 A 12/20/I1 Lot I S of Sweet Clover Lane 333 2 0 127.9 9.0 114.9 10.8 90 90 56 12/20/I1 Lot I S of Sweet Clover Lane 336 1 0 119.9 12.0 111.0 12.5 93 90 57 12/21/1I Lot lSofSweet Clover Lane 337 1 0 119.9 12.0 108.8 13.1 91 90 58 12/21/1I Lot S of Sweet Clover Lane 338 I 0 119.9 12.0 109.2 12.8 91 90 59 12/21/11 Lot I W of Holly Leaf Court 337 2 0 127.9 9.0 119.0 9.6 93 90 60 12/21/I1 Lot I W of Holly Leaf Court 338 2. 0 127.9 9.0 115.8 11.0 91 90 Project No. 07671-52-02 - . January 17, 2012 ........................................... TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location Elev. or Depth Curve No. Plus 3/4' Rock (%) Adj. MDD (pcf) Adj. OMC (%) Field Dry Dens. (pcf) Field Moist. Cont. (%) Field Rel. Camp. (%) Reqd. Rel. Comp. (%) 61 12/22/I1 Lot I SW of White Sage Way 327 2 0 127.9 9.0 117.0 9.9 91 90 62 12/22/I1 Lot I SW of White Sage Way 328 2 0 127.9 9.0 115.4 11.2 90 90 63 12/22/11 Lot I W of Sweet Clover/White Sage . 334 2 0 127.9 9.0 118.3 11.9 92 90 64 12/22/11 Lot I W of Sweet Clover/White Sage 335 1 0 119.9 12.0 108.7 14.1 91 90 SZ 65 12/23/11 Buttress Keyway 286 1 0 119.9 12.0 107.6 12.0 90 90 SZ 66 12/23/I1 Buttress Keyway 289 1 0 119.9 12.0 107.5 13.9 90 90 SZ 67 12/27/11 Buttress Keyway 293 2 0 127.9 9.0 115.7 10.5 90 90 SZ 68 12/27/11 Buttress Keyway 296 2 0 127.9 9.0 116.0. 11.0 91 90 SZ 69 12/27/I1 Buttress Keyway , 298 2 0 127.9 9.0 117.2 11.7 92 90 SZ 70 12/27/11 Buttress Keyway 301 2 0 127.9 9.0 118.0 11.2 92 90 SZ 71 12/27/1I Buttress Keyway 303 2 0 127.9 9.0 116.7 10.5 91 . 90 SZ 72 12/27/I1 Buttress Keyway. 303 2 0 127.9 9.0 116.5 11.8 91 90 SZ 73 12/28/I1 Buttress Keyway 305 1 0 119.9 12.0 109.0 14.6 91 90 SZ 74 12/28/1I Buttress 305 1 0 119.9 12.0 109.8 12.4 92 90 ST 75 12/28/I1 Wall 8 Basin 317 1 0 119.9 12.0 111.8 12.8 93 90 ST 76 12/28/11 Wall 8 Basin 320 2 0 127.9 9.0 117.4 11.2 92 90 SZ 77 12/28/11 Buttress 308 2 0 127.9 9.0 117.9 10.1 92 90 SZ 78 12/28/11 Buttress 308 1 .0 119.9 12.0 108.5 12.6 90 90 SZ 79 12/28/11 Buttress . . 311 2 0 127.9 9.0 115.8 11.0 91 90 SZ 80 12/28/11 Buttress - 311 .1 0 119.9 12.0 112.0 13.2 93 90 SZ 81 12/28/11 Buttress 314 2 0 127.9 9.0 115.6 10.8 90 90 SZ 82 12/28/11 Buttress 314 2 0 127.9 9.0 115.8 10.1 91 90 83 12/29/11 Lot I N of White Sage Way 325 1 0 119.9 12.0 107.7 14.3 90 90 84 12/29/11 Lot I N of White Sage Way . 326 2 0 127:9 9.0 118.6 11.0 93 90 85 12/29/1I Lot I N of White Sage Way 325 2 0 127.9 9.0 116.9 10.3 91 90 86 12/29/1I Lot I N of White Sage Way 326 2 0 127.9 9.0 119.4 9.4 93 90 ST 87 12/30/11 Buttress 313 1 0 119.91 12.0 107.9 12.6 90 90 ST 88 12/30/11 Buttress ' 309 2 0 127.9 9.0 116.6 11.0 91 90 89 12/30/11 Lot I N of White Sage Way 326 2 0 127.9 90. ' 115.6 12.0 90 90 90 12/30/I1 Lot I N of White Sage Way 328 2 0 127.9 9.0 117.3 11.5 92 90 SZ 91 12/30/11 Buttress . 317 1 0 119.9 12.0 108.1 13.1 90 90 Project No. 07671-52-02 . January 17, 2012 ............................................ TABLE I SUMMARY OF FIELD DENSITY TEST RESULTS Test No. Date Location SZ 92 12/30/1I Buttress SZ 93 12/30/I1 Buttress SZ 94 01/03/12 Buttress SZ 95 01/03/12 Buttress SZ 95 A 01/03/12 Buttress SZ 96 01/03/12 Buttress SZ 97 01/03/12 Buttress SZ 98 01/03/12 Lot SZ 99 01/04/12 Lot SZ 100 01/04/12 Buttress 101 01/04/12 Lot I Wof Sweet Clover Lane SZ 102 01/04/12 Lot I N of White Sage Way SZ 103 0I/04/12 Lot I N of White Sage Way ST 104 01/04/12 Lot I S of Sweet Clover Lane ST 105 01/04/12 Lot I S of Sweet Clover Lane FG 106 01/04/12 Lot 1 5 of Sweet Clover Lane FG 107 01/04/12 Lot I S of Sweet Clover Lane SZ 108 01/04/12 Buttress SZ 109 01/04/12 Lot SZ 110 01/05/12 Buttress III 01/05/12 Lot I W of Sweet Clover Lane SZ 112 01/05/12 Lot SZ 113 01/05/12 Buttress SZ 114 01/05/12 Lot 115 01/05/12 Lot I Wof Sweet Clover Lane SZ 116 01/05/12 Lot SZ 117 01/05/12 Lot Elev. or Depth Curve No. Plus 3/4 Rock (%) Adj. MDD (pcf) Adj. OMC (%) Field Dry Dens. (pcf) Field Moist. Cont. (%) Field Rel. Comp. (%) Reqd. Rel. Comp. (%) 317 1 0 119.9 12.0 108.1 13.8 90 90 317 1 . 0 119.9 12.0 109.8 14.2 92 90 319 1 0 119.9 12.0 109.8 12.0 92 90 320 1 0 119.9 12.0 106.0 9.4 88 90 320 1 0 119.9 12.0 108.4 12.5 90 90 323 1 - 0 119.9 12.0 111.4 14.1 93 90 317 I 0 119.9 12.0 111.6 .12.2 93 90 320 1 0 119.9 12.0 109.8 13.4 92 90 322 2 0 127.9 9.0 115.9 11.9 91 90 325 2 0 127.9 9.0 117.5 10.3 - 92 90 326 1 0 119.9 12.0 108.4 12.5 90 90 331 1 0 119.9 12.0 109.0 12.1 91 90 332 I 0 119.9 12.0 108.5 13.0 90 90 330 2 0 127.9 9.0 115.8 9.5 91 90 335 2 0 127.9 9.0 115.9 10.2 91 90 338 2 0 127.9 9.0 116.7 11.1 91 90 339 2 0 127.9 9.0 117.5 9.1 92 90 328 2 0 127.9 9.0 121.1 12.0 95 90 324 2 0 127.9 9.0 119.3 11.1 93 90 331 2 0 127.9 9.0 115.9 10.1 91 90 331 2 0 127.9 9.0 117.5 10.5 92 . 90 325 2 0 .127.9 9.0 116.9 11.0 91 90 333 2 0 127.9 9.0 115.8 12.4 91 90 328 2 0 127.9 9.0 119.2 11.7 93 90 335 2 0 127.9 9.0 116.2 11.4 91 90 331 1 0 119.9 ----------------------------------------------------------------------------------------------------------------------------------------- 12.0 110.4 15.3 92 90 328 2 0 127.9 9.0 117.0 10.9 91 90 Project No. 07671-52-02 . January 17, 2012 TABLE I EXPLANATION OF CODED TERMS - TEST SUFFIX A, B, C,. . . : Retest of previous density test failure,following moisture conditioning and/or recompaction. - S-TRIKE-OUT Fill in area of density test failure was removed and replaced with properly compacted,fihl soil. - PREFIX CODE DESIGNATION FOR TEST NUMBERS FG - FINISH GRADE ST - SLOPE TEST SZ - SLOPE ZONE - CURVE NO. Corresponds to-curve numbers listed in the summary of laboratory maximum dry density and optimum moisture content test results table for selected fill soil samples encountered during testing and observation. - ROCK CORRECTION For density tests with rock percentage greater than zero, laboratory maximum dry density and optimum moisture content were adjusted for rock content. For tests with rock content equal to zero, laboratory maximum dry density and optimum moisture content values are unadjusted. -TYPE OF TEST . SC: Sand Cone Test (ASTM D1556) NU: Nuclear Density Test (ASTM D2922) OT: Other - ELEVATION/DEPTH Test elevations/depths have been rounded to the, nearest whole foot. Project No. 07671-52-02 - January 17, 2012 TABLE II SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM 01557 Sample No. Description Maximum Dry Density (pcf) Optimum Moisture Content (% dry weight) Dark brown, Silty, fine to medium SAND 119.9 12.0 2 Brown, Silty, fine to medium SAND 127.9 9.0 TABLE III SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM:D 4829: Building Pad Nos. . Sample No. Moisture Content(%) Dry Density (pCI) Expansion Index - Soil Expansion Classification Before Test After Test 35 through 37 El-I 9.8 16.8 114.0 2 Very Low TABLE IV SUMMARY OF WATER SOLUBLE SULFATE LABORATORY TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Water Soluble Sulfate (%) . Sulfate Exposure El-I 0.039 Negligible Project No. 07671-52-02 January 17, 2012 ........................................... TABLE SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS MUROYA PROPERTY Building Pad No. Pad Condition Approximate Maximum Differential Fill Thickness (feet) Approximate Maximum Depth of Fill (feet) Expansion Index Recommended Foundation Category 35 Fill 12 22 2 II 36 Fill 14 24 2 II 37 Fill 14 24 2 II TABLE VI SUMMARY OF 2010 CBC SITE CLASS MUROYA PROPERTY Lot Nos. 2010 CBC Soil Profile Type 35 through 37 D