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HomeMy WebLinkAboutCT 15-05; QUARRY CREEK PA R-3 AND R-8; FINAL SOILS REPORT; 2016-07-21FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING QUARRY CREEK R-3 (LOTS 1 THROUGH 17) AND R-8 CARLSBAD, CALIFORNIA PREPARED FOR CORNERSTONE COMMUNITIES SAN DIEGO, CALIFORNIA JULY 21, 2016 PROJECT NO. 07135-42-05 Project No. 07135-42-05 July 21, 2016 Cornerstone Communities 4365 Executive Drive, Suite 600 San Diego, California 92121 Attention: Mr. Jack Robson Subject: FINAL REPORT OF TESTING AND OBSERVATION SERVICES PERFORMED DURING SITE GRADING QUARRY CREEK R-3 (LOTS 1 THROUGH 17) AND R-8 CARLSBAD, CALIFORNIA Dear Mr. Robson: In accordance with your request, we have performed compaction testing and observation services during grading for Quarry Creek R-3 and R-8. We performed our services during the period of July 7, 2015 through July 11, 2016. The scope of our services included the following: • Observing the grading operation, including processing the upper surface of the previously compacted fill and the placement of compacted fill. • Performing in-place density tests in fill placed and compacted at the site. • Performing laboratory tests to aid in evaluating compaction characteristics of various soil conditions encountered. We also performed laboratory testing on soil samples collected during grading activities and near finish grade to evaluate expansion characteristics, and where applicable, water-soluble sulfate content. • Preparing an as-graded geologic map. • Preparing an interim report of grading dated April 14, 2016 • Preparing this final report of grading. The purpose of this report is to document that the grading of subject project has been performed in substantial conformance with the recommendations of the project update geotechnical report. GENERAL Quarry Creek site is located south of State Route 78 and west of College Boulevard in the city of Carlsbad, California. Areas R-3 and R-8 are located within the south eastern portion of the overall GEOCON INCORPORATED GEOTECHNICAL ■ ENVIRONMENTAL ■ 6960 Flanders Drive ■ San Diego, California 92121-297 4 ■ Telephone 858.558.6900 ■ Fax 858.558.6159 Project No. 07135-42-05 - 2 - July 21, 2016 Quarry Creek development (see Vicinity Map, Figure 1). Area R-3 consists of 17 lots designated for high density residential units. R-8 is a community recreation lot. LB3 Enterprises Incorporated performed the grading. Project Design Consultants prepared the grading plans titled Mass Grading Plans for Quarry Creek, HDP 11-04, Drawing No. 484-5A, Carlsbad California, with a City of Carlsbad approval date of June 4, 2015. The grading plans showed sheet graded pads for R3 and R-8. However, grading was performed to the pad grades shown on SB&O, Incorporated plans titled Rough Grading Plans for Quarry Creek Planning Area R-3, dated August 12, 2015. Geocon Incorporated prepared the project geotechnical report titled Update Geotechnical Investigation, Quarry Creek, Carlsbad/Oceanside, California, prepared by Geocon Incorporated, dated February 24, 2015 (Project No. 07135-42-05) and Addendum to Update Geotechnical Investigation, Quarry Creek, Carlsbad/Oceanside, California, dated March 17, 2015. The following are additional geotechnical reports pertinent to the project: 1. Final Report of Testing and Observation Services During Site Grading, Quarry Creek, Carlsbad, California, prepared by Geocon Incorporated, dated April 4, 2013 (Project No. 07135-42-02). 2. Update Report, Quarry Creek R-3, Carlsbad California, prepared by Geocon Incorporated, dated May 15, 2015 (Project No. 07135-42-05). We used an AutoCAD file of the grading plans provided by SB&O as the base map to present as- graded geology and the approximate locations of in-place density tests (Figures 2, map pocket). The map depicts slopes, building pads, streets and, current and previous ground topography. References to elevations and locations herein are based on surveyors’ or grade checkers’ stakes in the field, elevation shots taken with a Global Positioning System (GPS) unit by the grading contractor, and/or interpolation from the referenced grading plan. Geocon Incorporated does not provide surveying services and, therefore, expresses no opinion regarding the accuracy of the as-graded elevations or surface geometry with respect to the approved grading plans or proper surface drainage. GRADING Previous Grading Portions of the Quarry Creek property have undergone many years of mining, crushing, and screening to produce commercial aggregate products. The majority of previous mining activity occurred in the eastern and southern portions of the overall Quarry Creek site. Mining resulted in undocumented fills and some compacted fill across the former mined areas. Project No. 07135-42-05 - 3 - July 21, 2016 Reclamation grading of the previously mined area commenced in July 2011 and was completed in December 2012. During reclamation grading, undocumented fills were removed and replaced as compacted fill. Drop structures, levees, and rock revetment slopes were constructed along and in Buena Vista Creek drainage. Reclamation grading resulted in removal of undocumented fill and replacement with compacted fill on the south side of Buena Vista Creek and majority of the areas north of the creek. Reclamation grading resulted in large sheet-graded pads in the R-3 and R-8 areas. A summary of observations and compaction tests performed during reclamation grading is contained in our April 2013 as-graded report. Recent Grading Grading covered under this report consisted of cuts from existing reclamation grades of approximately 7 feet and fills up to 15 feet. The surface of existing compacted fill was scarified, moisture conditioned, and recompacted prior to receiving additional fill. Fill soils were then placed and compacted in layers until design elevations were attained. Fills were placed in lifts no thicker than would allow for adequate bonding and compaction. Grading generally resulted in an approximately three foot-thick soil cap that generally consist of very low to medium expansive materials. In general, fill materials placed during grading consist of clayey to silty sand. Oversized rock (material > 6 inches) was placed at least three feet below design finish grade in graded areas. Rock greater than 12 inches exists within the compacted fill placed during previous phases of grading. Oversize rock was spread out within the compacted fill areas such that soil around the oversize rock could be compacted by the grading equipment. Although particular attention was given to restricting oversize material placement to the criteria described above, some oversize chunks could be present in the upper portions of the fill areas. During the grading operation, we observed compaction procedures and performed in-place density tests to evaluate the dry density and moisture content of the fill material. We performed in-place density tests in general conformance with ASTM D 6938, Standard Test Method for In-Place Density and Moisture Content of Soil and Soil-Aggregate by Nuclear Methods. A summary of in-place density and moisture content tests are presented on Table I. Other units within the Quarry Creek development were graded concurrently with R-3 and R-8. Therefore, the field density tests shown on Table I are not in sequential order. Where fill soil contained rock larger than ¾-inch, a correction was made to the laboratory maximum dry density and optimum moisture content using methods suggested by AASHTO T224. The values of maximum dry density and optimum moisture content presented on Table I reflect these corrections. Project No. 07135-42-05 - 4 - July 21, 2016 In general, in-place density test results indicate fill soils have a dry density of at least 90 percent of the laboratory maximum dry density at or slightly above optimum moisture content at the locations tested. The approximate locations of in-place density tests taken during grading specific to R-3 and R-8 are shown on Figure 2. We performed laboratory tests on samples of soil used for fill to evaluate moisture-density relationships, optimum moisture content, and maximum dry density (ASTM D 1557), and shear strength characteristics (AASHTO T-236). Additionally, we performed laboratory tests on soil samples collected at various stages of grading and near finish grade (soil fill cap) to evaluate expansion potential (ASTM D 4829) and where applicable, water-soluble sulfate content (California Test No. 417). Results of the laboratory tests are summarized on Tables II through IV. Slopes Fill slopes constructed during the recent phase of grading have an approximate inclination of 2:1 (horizontal:vertical) or flatter, with maximum height of approximately 20 feet. Fill slopes built during the previous phase of grading, located along the northern portion of R-3 are also 2:1 with approximate height of 45 feet. The outer approximately 15 feet of fill slopes were constructed with granular soil and were either over-filled and cut back or were track-walked with a bulldozer during grading in substantial conformance with the recommendations of the project geotechnical report. The project slopes (recently and previously graded) have a calculated factor of safety of at least 1.5 under static conditions with respect to both deep-seated failure and shallow sloughing conditions. A cut slope with an approximate height of 15 feet and inclination of 1.5:1 (horizontal:vertical) was constructed at the intersection of Marron Road and El Salto Fall Road. The cut slope was excavated into moderately weathered Salto Intrusive bedrock. Our field observation indicates that this slope is grossly and surficially stable. All 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 tops of slopes. Finish Grade Soil Conditions Laboratory test results and field observations indicate that the prevailing soil conditions within the upper approximately three feet of finish grade have an expansion potential (EI) of 50 or less and considered as low expansive as defined by ASTM D 4829. These soils are classified as expansive (EI >20) as defined by 2013 California Building Code (CBC) Section 1803.5.3. Table 1 presents soil classifications based on the expansion index per ASTM D 4829 and the CBC. Table III presents a Project No. 07135-42-05 - 5 - July 21, 2016 summary of expansion index test results for the prevailing subgrade soils at Quarry Creek, Areas R-3 and R-8. TABLE 1 SOIL CLASSIFICATION BASED ON EXPANSION INDEX ASTM D 4829 Expansion Index (EI) ASTM Expansion Classification CBC Expansion Classification 0 – 20 Very Low Non-Expansive 21 – 50 Low Expansive 51 – 90 Medium 91 – 130 High Greater Than 130 Very High We performed laboratory water-soluble sulfate testing on samples obtained for expansion testing to assess whether the soil contains sulfate concentrations high enough to damage normal Portland cement concrete. 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 “Not Applicable” sulfate exposure and “S0” sulfate exposure class to concrete structures as defined by 2013 CBC Section 1904 and ACI 318-08 Sections 4.2 and 4.3. Table 2 presents a summary of concrete requirements set forth by 2013 CBC Section 1904 and ACI 318. 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. TABLE 2 REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS Sulfate Exposure Exposure Class Water-Soluble Sulfate Percent by Weight Cement Type Maximum Water to Cement Ratio by Weight Minimum Compressive Strength (psi) Not Applicable S0 0.00-0.10 -- -- 2,500 Moderate S1 0.10-0.20 II 0.50 4,000 Severe S2 0.20-2.00 V 0.45 4,500 Very Severe S3 > 2.00 V+Pozzolan or Slag 0.45 4,500 Project No. 07135-42-05 - 6 - July 21, 2016 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, if improvements that could be susceptible to corrosion are planned, further evaluation by a corrosion engineer should be performed. SOIL AND GEOLOGIC CONDITIONS In general, the soil and geologic conditions encountered during grading were found to be similar to those described in the referenced project geotechnical report. The site is underlain by compacted fill soils (Qcf) overlying previously compacted fill (Qpcf), Terrace Deposits (Qt), Santiago Formation (Ts) and the Salto Intrusive bedrock (Jspi). The as-graded geologic map (Figure 2) has been annotated to show a general representation of the as- graded geologic conditions observed during grading. Geologic contacts should be considered approximate. CONCLUSIONS AND RECOMMENDATIONS 1.0 General 1.1 Based on observations and test results, it is the opinion of Geocon Incorporated that grading, which is the subject of this report, has been performed in substantial conformance with the recommendations of the referenced project geotechnical reports. Soil and geologic conditions encountered during grading that differ from those anticipated by the project geotechnical reports are not uncommon. Where such conditions required a significant modification to the recommendations of the project geotechnical reports, they have been described herein. 1.2 No soil or geologic conditions were observed during grading that would preclude the continued development of the property as planned. Based on laboratory test results and field observations, it is our opinion that the fill soils placed during grading have been compacted to at least 90 percent relative compaction. 1.3 Excavations for improvements, such as sewer lines, storm drains, etc. that extend through the soil cap and/or into the Salto Intrusive bedrock or below the rock hold down may encounter oversize rock or very hard rocks potentially resulting in difficult excavation conditions. The potential for these conditions should be taken into consideration when determining the type of equipment to utilize for future grading or trenching operations. The oversize material may require special handling techniques and exportation. Project No. 07135-42-05 - 7 - July 21, 2016 1.4 References to fill thickness or capping of pads are approximate and may be affected by subsequent fine grading to achieve proper surface drainage. 2.0 Future Grading 2.1 Any additional grading performed at the site should be accomplished in conjunction with our observation and compaction testing services. Geocon Incorporated should review grading plans for any future grading prior to finalizing. All trench and wall backfill should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near or to slightly above optimum moisture content. This office should be notified at least 48 hours prior to commencing additional grading or backfill operations. 3.0 Seismic Design Criteria 3.1 We used the computer program U.S. Seismic Design Maps, provided by the USGS. Table 3.1 summarizes site-specific seismic design criteria including spectral response accelerations in accordance with 2013 California Building Code (CBC; Based on the 2012 International Building Code [IBC] and ASCE 7-10), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. We evaluated the Site Class based on the discussion in Section 1613.3.2 of the 2013 CBC and Table 20.3-1 of ASCE 7-10. The values presented in Table 3.1 are for the risk-targeted maximum considered earthquake (MCER). The site is characterized Site Class D based on the thickness of compacted fill. TABLE 3.1 2013 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2013 CBC Reference Site Class D Section 1613.3.2 MCER Ground Motion Spectral Response Acceleration – Class B (short), SS 1.067g Figure 1613.3.1(1) MCER Ground Motion Spectral Response Acceleration – Class B (1 sec), S1 0.413g Figure 1613.3.1(2) Site Coefficient, FA 1.073 Table 1613.3.3(1) Site Coefficient, FV 1.587 Table 1613.3.3(2) Site Class Modified MCER Spectral Response Acceleration (short), SMS 1.145g Section 1613.3.3 (Eqn 16-37) Site Class Modified MCER Spectral Response Acceleration (1 sec), SM1 0.656g Section 1613.3.3 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (short), SDS 0.763g Section 1613.3.4 (Eqn 16-39) 5% Damped Design Spectral Response Acceleration (1 sec), SD1 0.437g Section 1613.3.4 (Eqn 16-40) Project No. 07135-42-05 - 8 - July 21, 2016 3.2 Table 3.2 presents additional seismic design parameters for projects located in Seismic Design Categories D through F in accordance with ASCE 7-10 for the mapped maximum considered geometric mean (MCEG). TABLE 3.2 2013 CBC SEISMIC DESIGN PARAMETERS Parameter Value ASCE 7-10 Reference Mapped MCEG Peak Ground Acceleration, PGA 0.407g Figure 22-7 Site Coefficient, FPGA 1.093 Table 11.8-1 Site Class Modified MCEG Peak Ground Acceleration, PGAM 0.445g Section 11.8.3 (Eqn 11.8-1) 3.3 Conformance to the criteria presented in Tables 3.1 and 3.2 for seismic design does not constitute any guarantee or assurance that significant structural damage or ground failure will not occur in the event of a maximum level earthquake. 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 Slab-On-Grade Recommendations 4.1 The foundation recommendations that follow are for one- to three-story residential structures and are separated into categories dependent on the thickness and geometry of the underlying fill soils as well as the expansion index of the prevailing subgrade soils of a particular building pad (or lot). Table V presents the as-graded lot conditions and recommended foundation categories for Quarry Creek R-3 and R-8. Determination of fill thickness and geometry was based on interpretation of field conditions and review of the project grading plan. TABLE 4.1 FOUNDATION CATEGORY CRITERIA Foundation Category Maximum Fill Thickness, T (feet) Differential Fill Thickness, D (feet) Expansion Index (EI) I T<20 -- 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. Project No. 07135-42-05 - 9 - July 21, 2016 TABLE 4.2 CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Category Minimum Footing Embedment Depth (inches) Continuous Footing Reinforcement Interior Slab Reinforcement I 12 Two No. 4 bars, one top and one bottom 6x6-10/10 welded wire mesh at slab mid-point II 18 Four No. 4 bars, two top and two bottom No. 3 bars at 24 inches on center, both directions III 24 Four No. 5 bars, two top and two bottom No. 3 bars at 18 inches 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 (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 in a manner that prevents puncture. The project architect or developer should specify the vapor retarder based on the type of floor covering that will be installed and if the structure will possess a humidity controlled environment. 4.6 The project foundation engineer, architect, and/or developer should determine the thickness of bedding sand below the slab. In general, 3 to 4 inches of sand bedding is typically used. Geocon should be contacted to provide recommendations if the bedding sand is thicker than 6 inches. 4.7 The foundation design engineer should provide appropriate concrete mix design criteria and curing measures to assure proper curing of the slab by reducing the potential for rapid moisture loss and subsequent cracking and/or slab curl. The foundation design engineer should specify the concrete mix design and proper curing methods on the foundation plan. It Project No. 07135-42-05 - 10 - July 21, 2016 is critical that the foundation contractor understands and follows the recommendations presented on the foundation plan. 4.8 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 2013 CBC has updated the design requirements for post-tensioned foundation systems. 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 2013 CBC (Section 1805.8). Although this procedure was developed for expansive soil conditions, we understand 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 in 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 (PTI) 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 4.9 If the structural engineer proposes a post-tensioned foundation design method other than the 2013 CBC: • The 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. 4.10 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 Project No. 07135-42-05 - 11 - July 21, 2016 planned, the slab should possess a thickened edge with a minimum width of 12 inches and extend at least 6 inches below the clean sand or crushed rock layer. 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. The estimated maximum total and differential settlement for the planned structures due to foundation loads is 1- inch and ½-inch, respectively. Differential settlement is estimated to occur over a span of 40 feet. 4.14 Isolated footings, including PT foundation systems where footings are not reinforced with PT cables, should have the minimum embedment depth and width recommended for conventional foundations (see Section 4.1 through 4.3) 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 five feet in width, to the building foundation to reduce the potential for future separation to occur. Project No. 07135-42-05 - 12 - July 21, 2016 4.16 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 appropriate in any such concrete placement. 4.17 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 or cut slopes regardless of height, 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. • For fill slopes greater than 20 feet high, 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. A post-tensioned slab and foundation system or mat foundation system can be used to help reduce potential foundation distress associated with slope creep and lateral fill extension. 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 swimming pools are planned, Geocon Incorporated should be contacted for a review of specific site conditions. • 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 that 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. 4.18 The exterior flatwork recommendations provided herein assumes that the near surface soils are very low to medium (EI < 90). Exterior slabs not subjected to vehicular traffic should be a minimum of four inches thick and reinforced with 6 x 6-6/6 welded wire mesh. The mesh should be placed in the middle of the slab. Proper mesh positioning is critical to future performance of the slabs. The contractor should take extra measures to provide Project No. 07135-42-05 - 13 - July 21, 2016 proper mesh placement. Prior to construction of slabs, the upper 12 inches of subgrade soils should be moisture conditioned at or slightly above optimum moisture content and compacted to at least 90 percent of the laboratory maximum dry density per ASTM 1557. 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. The occurrence may be reduced and/or controlled by: (1) limiting the slump of the concrete, (2) proper concrete placement and curing, and by (3) the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. 4.20 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 pcf. Where the backfill will be inclined at 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. Expansive soil should not be used as backfill material behind retaining walls. 5.2 Where walls are restrained from movement at the top, an additional uniform pressure of 8H psf (where H equals the height of the retaining wall portion of the wall in feet) should be added to the active soil pressure where the wall possesses a height of 8 feet or less and 12H where the wall is greater than 8 feet. For retaining walls subject to vehicular loads within a horizontal distance equal to two-thirds the wall height, a surcharge equivalent to two feet of fill soil should be added (soil total unit weight 130 pcf). 5.3 Soil to be used as backfill should be stockpiled and samples obtained for laboratory testing to evaluate its suitability for use as wall backfill. Modified lateral earth pressures will be required if backfill soils do not meet the required expansion index. Standard wall designs, if used, are based on a specific active lateral earth pressure and/or soil friction angle. On- site soils might not meet the design values used for the standard wall design. Geocon Project No. 07135-42-05 - 14 - July 21, 2016 Incorporated should be consulted if standard wall designs will be used to assess the suitability of on-site soil for use as wall backfill. 5.4 Unrestrained walls will move laterally when backfilled and loading is applied. The amount of lateral deflection is dependent on the wall height, the type of soil used for backfill, and loads acting on the wall. The wall designer should provide appropriate lateral deflection quantities for planned retaining walls structures, if applicable. These lateral values should be considered when planning types of improvements above retaining wall structures. 5.5 Retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and should be 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 granular (EI < 50) free-draining backfill material with no hydrostatic forces or imposed surcharge load. A typical retaining wall drainage detail is presented on Figure 4. If conditions different than those described are expected, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. 5.6 In general, wall foundations having a minimum depth and width of 1 foot may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 3 feet below the base of the wall has an Expansion Index < 90. The recommended allowable soil bearing pressures 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. 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. 5.7 The structural engineer should determine the seismic design category for the project in accordance with Section 1613 of the CBC. If the project possesses a seismic design category of D, E, or F, retaining walls that support more than 6 feet of backfill should be designed with seismic lateral pressure in accordance with Section 18.3.5.12 of the 2013 CBC. The seismic load is dependent on the retained height where H is the height of the wall, in feet, and the calculated loads result in pounds per square foot (psf) exerted at the base of the wall and zero at the top of the wall. A seismic load of 21H should be used for design. We used the peak ground acceleration adjusted for Site Class effects, PGAM, of 0.445 g calculated from ASCE 7-10 Section 11.8.3 and applied a pseudo-static coefficient of 0.33. Project No. 07135-42-05 - 15 - July 21, 2016 5.8 For resistance to lateral loads, an allowable passive earth pressure equivalent to a fluid density of 300 pcf is recommended for footings or shear keys poured neat against properly compacted granular fill soils or undisturbed formation materials. The allowable passive pressure assumes a horizontal surface extending away from the base of the wall at least 5 feet or three times the surface generating the passive pressure, whichever is greater. The upper 12 inches of material not protected by floor slabs or pavement should not be included in the design for lateral resistance. Where walls are planned adjacent to and/or on descending slopes, a passive pressure of 150 pcf should be used in design. 5.9 An allowable friction coefficient of 0.35 may be used for resistance to sliding between soil and concrete. This friction coefficient may be combined with the allowable passive earth pressure when determining resistance to lateral loads. 5.10 The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of eight feet. In the event that walls higher than eight feet or other types of walls (i.e., soil nail, MSE walls) are planned, Geocon Incorporated should be consulted for additional recommendations. 6.0 Slope Maintenance 6.1 Slopes that are steeper than 3:1 (horizontal:vertical), under conditions that are both difficult to prevent and predict, may be susceptible to near-surface slope instability. The instability is typically limited to the outer 3 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 either be 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. Project No. 07135-42-05 - 16 - July 21, 2016 7.0 Detention Basin and Bioswale Recommendations 7.1 Any permanent detention basins, bioswales and bio-remediation areas should be designed by the project civil engineer and reviewed by Geocon Incorporated. Typically, bioswales consist of a surface layer of vegetation underlain by clean sand. A subdrain should be provided beneath the sand layer. Prior to discharging into the storm drain pipe, a seepage cutoff wall should be constructed at the interface between the subdrain and storm drainpipe. The concrete cut-off wall should extend at least 6-inches beyond the perimeter of the gravel-packed subdrain system. 7.2 Distress may be caused to planned improvements and properties located hydrologically downstream or adjacent to these devices. 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 and adjacent 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. Due to site soil and geologic conditions, permanent bioswales and bio-remediation areas should be lined with an impermeable barrier, such as a thick visqueen, to prevent water infiltration in to the underlying compacted fill. Temporary detention basins in areas where improvements have not been constructed do not need to be lined. 7.3 The landscape architect should be consulted to provide the appropriate plant recommendations. If drought resistant plants are not used, irrigation may be required. 8.0 Site Drainage and Moisture Protection 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 2013 CBC 1803.3 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 In the case of basement walls or building walls retaining landscaping areas, a water- proofing system should be used on the wall and joints, and a Miradrain drainage panel (or similar) should be placed over the waterproofing. The project architect or civil engineer should provide detailed specifications on the plans for all waterproofing and drainage. Project No. 07135-42-05 - 17 - July 21, 2016 8.3 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for prolonged periods of time. 8.4 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 the use of drains to collect excess irrigation water and transmit it to drainage structures, or impervious above-grade planter boxes. In addition, where landscaping is planned adjacent to the pavement, we recommend construction of a cutoff wall along the edge of the pavement that extends at least six inches below the bottom of the base material. LIMITATIONS The conclusions and recommendations contained herein apply only to our work with respect to grading, and represent conditions at the date of final observation on July 11, 2016. 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, expressed 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. It is the responsibility of owner to ensure that the information and recommendations contained herein are brought to the attention of the architect and engineer for the project, are incorporated into the plans, and that the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. Recommendations that pertain to the future maintenance and care for the property should be brought to the attention of future owners of the property or portions thereof. 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. Project No. 07135-42-05 - 18 - July 21, 2016 Should 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 Ali Sadr CEG 1778 Rodney C. Mikesell GE 2533 AS:RCM:dmc (4/del) Addressee TABLE 1 SUMMARY OF FIELD DENSITY TEST RESULTS Project Name:Project No.: Pre. No. Re. 1 07/08/15 R-3 Lot 2 108.0 13 0 118.1 13.3 109.8 15.0 93 90 2 07/08/15 R-3 Lot 4 111.0 14 0 124.6 11.3 111.6 11.4 90 90 3 07/08/15 R-3 Lot 4 111.0 14 0 124.6 11.3 111.8 11.3 90 90 4 07/08/15 R-3 Lot 13 110.0 14 0 124.6 11.3 111.9 14.2 90 90 5 07/08/15 R-3 NE Lot 12 111.0 13 0 118.1 13.3 109.7 13.1 93 90 6 07/08/15 R-3 N Lot 6 112.0 14 0 124.6 11.3 113.9 12.9 91 90 7 07/09/15 R-3 Lot 1 108.0 13 0 118.1 13.3 110.5 13.8 94 90 8 07/09/15 R-3 Lot 2 109.0 9 0 125.2 11.1 117.3 12.2 94 90 9 07/09/15 R-3 Lot 3 110.0 12 0 130.8 9.5 120.0 9.5 92 90 10 07/09/15 R-3 Lot 4 112.0 14 0 124.6 11.3 114.2 12.7 92 90 11 07/09/15 R-3 Lot 5 112.0 9 0 125.2 11.1 116.3 11.6 93 90 12 07/09/15 R-3 N Lot 16 109.0 13 0 118.1 13.3 111.0 13.0 94 90 13 07/09/15 R-3 N Lot 14 111.0 12 0 130.8 9.5 118.2 9.1 90 90 14 07/09/15 R-3 N Lot 12 112.0 12 0 130.8 9.5 119.8 12.0 92 90 15 07/09/15 R-3 N Lot 16 113.0 9 0 125.2 11.1 115.7 14.0 92 90 16 07/09/15 R-3 Lot 17 109.0 13 0 118.1 13.3 110.6 13.3 94 90 17 07/09/15 R-3 Lot 14 111.0 13 0 118.1 13.3 109.3 13.5 93 90 18 07/09/15 R-3 Lot 6 113.0 14 0 124.6 11.3 114.4 11.2 92 90 19 07/10/15 R-3 Lot 1 110.0 13 0 118.1 13.3 109.6 13.0 93 90 20 07/10/15 R-3 Lot 2 112.0 14 0 124.6 11.3 115.6 11.9 93 90 21 07/10/15 R-3 Lot 3 114.0 14 0 124.6 11.3 114.2 11.9 92 90 22 07/10/15 R-3 Lot 4 115.0 14 0 124.6 11.3 116.2 12.9 93 90 23 07/10/15 R-3 Lot 5 116.0 14 0 124.6 11.3 114.1 13.7 92 90 24 07/10/15 R-3 E Lot 5 117.0 13 0 118.1 13.3 108.9 15.6 92 90 25 07/10/15 R-3 N Lot 6 116.0 13 0 118.1 13.3 109.2 16.2 92 90 26 07/10/15 R-3 NE Lot 12 115.0 13 0 118.1 13.3 108.5 14.0 92 90 27 07/10/15 R-3 N Lot 13 113.0 13 0 118.1 13.3 110.1 17.1 93 90 28 07/10/15 R-3 N Lot 5 112.0 13 0 118.1 13.3 107.4 14.8 91 90 34 07/13/15 R-3 Lot 16 112.0 14 0 124.6 11.3 112.3 11.1 90 90 Relative Compaction (%) Test No.Date Location Elev. or Depth (feet) Curve No. Quarry Creek Required Relative Compaction (%) 07135-42-05 >¾" Rock (%) Max. Dry Density (pcf) Opt. Moist Content (%) Field Dry Density (pcf) Field Moisture Content (%) ~GEOCON TABLE 1 SUMMARY OF FIELD DENSITY TEST RESULTS Project Name:Project No.: Pre. No. Re. Relative Compaction (%) Test No.Date Location Elev. or Depth (feet) Curve No. Quarry Creek Required Relative Compaction (%) 07135-42-05 >¾" Rock (%) Max. Dry Density (pcf) Opt. Moist Content (%) Field Dry Density (pcf) Field Moisture Content (%) 35 07/13/15 R-3 Lot 15 113.0 14 0 124.6 11.3 113.6 13.9 91 90 36 07/13/15 R-3 Lot 14 114.0 13 0 118.1 13.3 109.3 15.9 93 90 37 07/13/15 R-3 Lot 12 115.0 13 0 118.1 13.3 110.2 12.3 93 90 38 07/13/15 R-3 Lot 6 116.0 14 0 124.6 11.3 114.5 13.7 92 90 39 07/13/15 R-3 E Lot 5 118.0 14 0 124.6 11.3 115.0 11.9 92 90 40 07/13/15 R-3 E Lot 5 119.0 13 0 118.1 13.3 111.5 15.0 94 90 41 07/13/15 R-3 NE Lot 12 117.0 13 0 118.1 13.3 108.1 17.5 92 90 42 07/13/15 R-3 N Lot 14 115.0 14 0 124.6 11.3 114.7 11.8 92 90 43 07/13/15 R-3 Lot 16 114.0 14 0 124.6 11.3 113.9 12.2 91 90 44 07/14/15 R-3 Lot 1 113.0 13 0 118.1 13.3 107.0 15.9 91 90 45 07/14/15 R-3 Lot 4 116.0 13 0 118.1 13.3 106.2 13.4 90 90 46 07/14/15 R-3 Lot 5 118.0 13 0 118.1 13.3 110.9 15.1 94 90 47 07/14/15 R-3 Lot 17 114.0 15 0 128.1 10.2 115.3 10.4 90 90 48 07/14/15 R-3 Lot 15 114.0 15 0 128.1 10.2 116.2 11.1 91 90 49 07/14/15 R-3 Lot 14 116.0 14 0 124.6 11.3 111.9 11.4 90 90 50 07/14/15 R-3 Lot 12 118.0 14 0 124.6 11.3 113.9 12.8 91 90 51 07/14/15 R-3 Lot 6 119.0 13 0 118.1 13.3 110.1 15.9 93 90 52 07/14/15 R-3 El Salto Fall Rd 112.0 13 0 118.1 13.3 111.0 15.0 94 90 53 07/14/15 R-3 El Salto Fall Rd 13+25 112.0 14 0 124.6 11.3 108.3 8.7 87 90 53 A 07/14/15 R-3 El Salto Fall Rd 13+25 112.0 14 0 124.6 11.3 113.5 12.2 91 90 55 07/15/15 R-3 Lot 17 110.0 13 0 118.1 13.3 109.1 13.4 92 90 56 07/15/15 R-3 Lot 15 110.0 13 0 118.1 13.3 110.1 14.4 93 90 57 07/15/15 R-3 Lot 14 111.0 13 0 118.1 13.3 110.1 13.3 93 90 58 07/15/15 R-3 E Lot 12 112.0 13 0 118.1 13.3 111.2 14.6 94 90 59 07/15/15 R-3 Lot 6 113.0 13 0 118.1 13.3 108.7 12.9 92 90 60 07/15/15 R-3 Lot 16 112.0 15 0 128.1 10.2 115.0 11.1 90 90 61 07/15/15 R-3 Lot 14 112.0 15 0 128.1 10.2 106.2 11.9 83 90 62 07/15/15 R-3 E Lot 12 113.0 13 0 118.1 13.3 105.1 9.4 89 90 62 A 07/15/15 R-3 E Lot 12 113.0 13 0 118.1 13.3 109.5 15.0 93 90 ~GEOCON TABLE 1 SUMMARY OF FIELD DENSITY TEST RESULTS Project Name:Project No.: Pre. No. Re. Relative Compaction (%) Test No.Date Location Elev. or Depth (feet) Curve No. Quarry Creek Required Relative Compaction (%) 07135-42-05 >¾" Rock (%) Max. Dry Density (pcf) Opt. Moist Content (%) Field Dry Density (pcf) Field Moisture Content (%) 63 07/15/15 R-3 Lot 9 115.0 12 0 130.8 9.5 116.4 6.6 89 90 63 A 07/15/15 R-3 Lot 9 115.0 12 0 130.8 9.5 120.6 10.0 92 90 64 07/15/15 R-3 Lot 15 112.0 13 0 118.1 13.3 108.3 14.0 92 90 65 07/15/15 R-3 Lot 13 114.0 14 0 124.6 11.3 112.8 12.2 91 90 66 07/15/15 R-3 Lot 12 115.0 14 0 124.6 11.3 111.6 13.2 90 90 67 07/15/15 R-3 Lot 9 116.0 14 0 124.6 11.3 113.1 10.9 91 90 68 07/15/15 R-3 Lot 7 117.0 14 0 124.6 11.3 111.9 11.6 90 90 69 07/16/15 R-3 Lot 7 118.0 15 0 128.1 10.2 115.9 10.9 90 90 70 07/16/15 R-3 Lot 9 117.0 15 0 128.1 10.2 117.3 10.5 92 90 71 07/16/15 R-3 E Lot 12 117.0 14 0 124.6 11.3 112.1 11.4 90 90 72 07/16/15 R-3 Lot 12 115.0 14 0 124.6 11.3 111.9 12.5 90 90 73 07/16/15 R-3 Lot 14 114.0 14 0 124.6 11.3 113.5 11.3 91 90 76 07/16/15 R-3 Lot 15 115.0 13 0 118.1 13.3 112.6 14.6 95 90 77 07/16/15 R-3 Lot 13 17.0 15 0 128.1 10.2 114.8 13.0 90 90 78 07/16/15 R-3 Lot 12 117.0 14 0 124.6 11.3 114.5 11.5 92 90 79 07/16/15 R-3 Lot 6 118.0 15 0 128.1 10.2 115.3 11.9 90 90 80 07/16/15 R-3 Lot 7 120.0 15 0 128.1 10.2 116.6 11.0 91 90 81 07/16/15 R-3 Lot 8 121.0 15 0 128.1 10.2 115.1 10.6 90 90 82 07/17/15 R-3 Lot 8 123.0 15 0 128.1 10.2 121.1 10.1 95 90 83 07/17/15 R-3 Lot 7 121.0 15 0 128.1 10.2 117.6 11.5 92 90 84 07/17/15 R-3 Lot 9 120.0 15 0 128.1 10.2 123.2 12.3 96 90 85 07/17/15 R-3 Lot 12 120.0 15 0 128.1 10.2 119.1 11.7 93 90 88 07/17/15 R-3 Lot 16 118.0 15 0 128.1 10.2 119.2 11.2 93 90 100 07/22/15 R-3 Lot 1 117.0 13 0 118.1 13.3 106.5 13.1 90 90 101 07/22/15 R-3 Lot 2 118.0 13 0 118.1 13.3 107.2 15.1 91 90 102 07/22/15 R-3 Lot 3 119.0 13 0 118.1 13.3 106.7 14.3 90 90 103 07/22/15 R-3 Lot 4 120.0 13 0 118.1 13.3 107.7 13.9 91 90 104 07/22/15 R-3 Lot 5 120.0 13 0 118.1 13.3 108.7 13.4 92 90 155 07/31/15 R-3 Lot 1 119.0 15 0 128.1 10.2 118.0 11.1 92 90 ~GEOCON TABLE 1 SUMMARY OF FIELD DENSITY TEST RESULTS Project Name:Project No.: Pre. No. Re. Relative Compaction (%) Test No.Date Location Elev. or Depth (feet) Curve No. Quarry Creek Required Relative Compaction (%) 07135-42-05 >¾" Rock (%) Max. Dry Density (pcf) Opt. Moist Content (%) Field Dry Density (pcf) Field Moisture Content (%) 156 07/31/15 R-3 Lot 2 120.0 15 0 128.1 10.2 115.2 9.5 90 90 157 07/31/15 R-3 Lot 3 121.0 15 0 128.1 10.2 115.7 10.3 90 90 158 07/31/15 R-3 Lot 4 123.0 15 0 128.1 10.2 117.3 11.0 92 90 159 07/31/15 R-3 Lot 5 124.0 15 0 128.1 10.2 116.6 10.2 91 90 160 07/31/15 R-3 Lot 16 120.0 15 0 128.1 10.2 119.1 10.1 93 90 161 07/31/15 R-3 Lot 14 121.0 13 0 118.1 13.3 110.9 13.7 94 90 162 07/31/15 R-3 Lot 12 123.0 13 0 118.1 13.3 110.6 16.0 94 90 163 07/31/15 R-3 Lot 6 124.0 13 0 118.1 13.3 108.7 12.9 92 90 164 07/31/15 R-3 Lot 15 121.0 14 0 124.6 11.3 113.8 10.9 91 90 235 08/12/15 R-3 E Lot 8 127.0 9 0 125.2 11.1 114.8 11.3 92 90 236 08/13/15 R-3 E Lot 8 131.0 5 0 130.9 8.9 124.2 11.1 95 90 240 08/13/15 R-3 Lot 1 115.0 17 0 112.7 15.5 103.9 15.3 92 90 FG 273 08/21/15 R-3 Lot 5 124.8 14 0 124.6 11.3 112.1 14.0 90 90 FG 274 08/21/15 R-3 Lot 4 124.0 15 0 128.1 10.2 115.6 10.2 90 90 FG 275 08/21/15 R-3 Lot 3 122.5 15 0 128.1 10.2 120.3 9.9 94 90 276 08/24/15 R-3 Lot 17 119.0 13 0 118.1 13.3 106.5 12.7 90 90 ST 277 08/24/15 R-3 N Slope 115.0 13 0 118.1 13.3 107.6 12.9 91 90 ST 278 08/24/15 R-3 N Slope 115.0 13 0 118.1 13.3 106.6 13.2 90 90 SZ 279 08/24/15 R-3 NE Corner 128.0 15 0 128.1 10.2 115.9 9.9 90 90 ST 280 08/25/15 R-3 N Slope 115.0 13 0 118.1 13.3 108.9 12.9 92 90 FG 281 08/25/15 R-3 Lot 2 121.6 14 0 124.6 11.3 113.3 11.9 91 90 SZ 282 08/25/15 R-3 E Slope Lot 8 133.0 14 0 124.6 11.3 110.1 8.1 88 90 SZ 282 A 08/25/15 R-3 E Slope Lot 8 133.0 14 0 124.6 11.3 114.9 11.5 92 90 SZ 283 08/25/15 R-3 E Slope Lot 8 134.0 14 0 124.6 11.3 106.5 9.1 85 90 SZ 283 A 08/25/15 R-3 E Slope Lot 8 134.0 14 0 124.6 11.3 113.1 10.9 91 90 FG 284 08/25/15 R-3 Lot 12 124.3 14 0 124.6 11.3 113.3 11.3 91 90 FG 285 08/25/15 R-3 Lot 13 124.3 15 0 128.1 10.2 120.8 9.6 94 90 FG 286 08/26/15 R-3 Lot 14 122.4 15 0 128.1 10.2 117.5 10.2 92 90 FG 287 08/26/15 R-3 Lot 15 122.3 15 0 128.1 10.2 114.7 13.0 90 90 ~GEOCON TABLE 1 SUMMARY OF FIELD DENSITY TEST RESULTS Project Name:Project No.: Pre. No. Re. Relative Compaction (%) Test No.Date Location Elev. or Depth (feet) Curve No. Quarry Creek Required Relative Compaction (%) 07135-42-05 >¾" Rock (%) Max. Dry Density (pcf) Opt. Moist Content (%) Field Dry Density (pcf) Field Moisture Content (%) SZ 288 08/26/15 R-3 E Slope Lot 8 137.0 14 0 124.6 11.3 113.7 11.7 91 90 SZ 289 08/26/15 R-3 E Slope Lot 8 137.0 14 0 124.6 11.3 112.6 11.1 90 90 FG 290 08/26/15 R-3 Lot 16 120.7 15 0 128.1 10.2 122.1 13.1 95 90 FG 291 08/26/15 R-3 Lot 17 120.6 15 0 128.1 10.2 119.8 9.8 94 90 SZ 292 08/26/15 R-3 E Slope Lot 8 142.0 14 0 124.6 11.3 113.1 11.5 91 90 SZ 293 08/26/15 R-3 E Slope Lot 8 141.0 14 0 124.6 11.3 113.3 12.1 91 90 FG 294 08/28/15 R-3 Lot 6 125.0 15 0 128.1 10.2 120.6 10.4 94 90 FG 295 08/28/15 R-3 Lot 9 128.5 15 0 128.1 10.2 115.2 10.6 90 90 ST 296 08/31/15 R-3 E Slope Lot 8 138.0 15 0 128.1 10.2 115.5 9.8 90 90 ST 297 08/31/15 R-3 E Slope Lot 8 138.0 15 0 128.1 10.2 115.0 10.0 90 90 FG 298 09/01/15 R-3 Lot 7 127.4 15 0 128.1 10.2 115.4 11.5 90 90 FG 299 09/01/15 R-3 Lot 8 127.4 15 0 128.1 10.2 124.1 9.8 97 90 FG 310 09/03/15 R-3 Lot 10 128.0 8 0 135.0 7.6 123.1 10.4 91 90 FG 311 09/03/15 R-3 Lot 11 128.8 8 0 135.0 7.6 124.7 9.4 92 90 774 06/17/16 R-3 Lot 1 116.0 12 0 130.8 9.5 119.5 13.9 91 90 775 06/17/16 R-3 Lot 1 117.0 12 0 130.8 9.5 123.2 10.6 94 90 776 06/17/16 R-3 Lot 1 117.0 12 0 130.8 9.5 120.7 12.8 92 90 777 06/20/16 R-3 Lot 1 117.0 12 0 130.8 9.5 123.9 10.2 95 90 778 06/20/16 R-3 Lot 1 118.0 12 0 130.8 9.5 122.1 12.4 93 90 779 06/20/16 R-3 Lot 1 117.0 12 0 130.8 9.5 126.6 9.9 97 90 780 06/20/16 R-3 Lot 1 118.0 12 0 130.8 9.5 119.5 14.1 91 90 781 06/21/16 R-3 Lot 1 119.0 12 0 130.8 9.5 122.9 11.9 94 90 782 06/21/16 R-3 Lot 1 119.0 12 0 130.8 9.5 123.4 11.5 94 90 782 Dup. 06/21/16 R-3 Lot 1 119.0 31 0 121.0 13.1 120.7 12.6 100 90 793 06/24/16 R-3 Lot 1 118.0 12 0 130.8 9.5 118.2 11.9 90 90 794 06/24/16 R-3 Lot 1 119.0 12 0 130.8 9.5 119.2 11.6 91 90 807 07/11/16 R-3 Lot 1 121.0 12 0 130.8 9.5 120.3 10.4 92 90 ~GEOCON TABLE 1 SUMMARY OF FIELD DENSITY TEST RESULTS Project Name:Project No.: Pre. No. Re. 32 07/13/15 R-8 110.0 13 0 118.1 13.3 107.5 16.2 91 90 33 07/13/15 R-8 110.0 13 0 118.1 13.3 106.6 18.1 90 90 256 08/17/15 R-8 111.0 13 0 118.1 13.3 107.4 16.7 91 90 FG 271 08/21/15 R-8 Rec Pad 112.0 14 0 124.6 11.3 115.7 11.3 93 90 FG 272 08/21/15 R-8 Rec Pad 112.5 13 0 118.1 13.3 108.3 12.8 92 90 Relative Compaction (%) Test No.Date Location Elev. or Depth (feet) Curve No. Quarry Creek Required Relative Compaction (%) 07135-42-05 >¾" Rock (%) Max. Dry Density (pcf) Opt. Moist Content (%) Field Dry Density (pcf) Field Moisture Content (%) ~GEOCON TABLE 1 EXPLANATION OF CODED TERMS AC Asphalt Concrete IT Irrigation Trench SL Sewer Lateral AD Area Drain JT Joint Trench SM Sewer Main B Base M Moisture Test SR Slope Repair CG Curb/Gutter MSE Mechanically Stabilized Earth Wall ST Slope Test DW Driveway RG Regrade SW Sidewalk ET Electrical Trench RWL Reclaimed Water Lateral SZ Slope Zone ETB Exploratory Trench RWM Reclaimed Water Main UT Utility Trench FB Footing Backfill SBT Subdrain Trench WB Wall Backfill FG Finish Grade SD Storm Drain WL Water Lateral GT Gas Trench SG Subgrade WM Water Main A, B, C, … R >¾" ROCK - ROCK CORRECTION The laboratory maximum dry density and optimum moisture content can be adjusted for in-place soil that possesses rock larger than ¾ inch. The curve no. is adjusted for the percentage of ¾ inch rock in accordacne with ASTM D 4718 or Woodward Clyde guidelines. TEST NO. PREFIX TEST NO. RE. Retest of previous density test failure following additional moisture conditioning or recompaction Fill in area of density test was removed during construction operations CURVE NO. Corresponds to the curve numbers presented in the summary of the laboratory maximum dry density and optimum moisture content test resluts. The field representative selected the curve no. based on the laboratory test results and field observations ELEVATION OR DEPTH Cooresponds to the elevation or the depth, in feet, of the in-place density/moisture content test. The value has been rounded to the nearest whole foot ~GEOCON Project No. 07135-42-05 July 21, 2016 TABLE II SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Sample No. Description Maximum Dry Density (pcf) Optimum Moisture Content (% dry weight) 5 Dark brown, Clayey, fine SAND 130.9 8.9 8 Olive brown, Sandy GRAVEL 135.0 7.6 9 Light greenish brown, Clayey, fine to coarse SAND 125.2 11.1 12 Reddish brown, Clayey, fine to coarse SAND, with GRAVEL 13.08 9.5 13 Light greenish brown, Silty, Sandy CLAY, some gravel 118.1 13.3 14 Light gray, Silty, fine to coarse SAND, with gravel 124.6 11.3 15 Light brown, Silty , fine to coarse SAND 128.1 10.2 17 Very dark brown to black Sandy CLAY 112.7 15.5 TABLE III SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Sample No. Representative Lot Moisture Content (%) Dry Density (pcf) Expansion Index ASTM Classification (per 2013 CBC) Before Test After Test EI-1 R-8, Rec Pad 10.0 21.3 109.8 43 Low EI-2 R-3, Lots 2 – 5 8.1 17.0 115.5 42 Low EI-3 R-3 Lots 12 and 13 9.6 18.5 112.3 36 Low EI-4 R-3, Lots 14and 15 9.6 17.1 113.3 26 Low EI-5 R-3, Lots 16 and 17 9.2 17.3 113.6 25 Low EI-6 R-3, Lots 6 and 9 9.2 18.4 112.4 30 Low EI-7 R-3, Lots 7 and 8 9.4 19.3 112.5 42 Low EI-8 R-3, Lots 10 and 11 8.5 16.3 113.9 21 Low EI-9 R-3, Lot 1 9.4 19.2 111.4 35 Low Project No. 07135-42-05 July 21, 2016 TABLE IV SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Representative Lot Water-Soluble Sulfate (%) Sulfate Exposure EI-1 R-8, Rec Pad 0.016 Not Applicable (S0) EI-2 R-3, Lots 2 - 5 0.018 Not Applicable (S0) EI-3 R-3 Lots 12 and 13 0.035 Not Applicable (S0) EI-4 R-3, Lots 14and 15 0.014 Not Applicable (S0) EI-5 R-3, Lots 16 and 17 0.001 Not Applicable (S0) EI-6 R-3, Lots 6 and 9 0.012 Not Applicable (S0) EI-7 R-3, Lots 7 and 8 0.095 Not Applicable (S0) EI-8 R-3, Lots 10 and 11 0.030 Not Applicable (S0) EI-9 R-3, Lot 1 0.017 Not Applicable (S0) TABLE V SUMMARY OF AS-GRADED BUILDING PAD CONDITIONS AND RECOMMENDED FOUNDATION CATEGORY FOR QUARRY CREEK, R-3 AND R-8 Lot No. Pad Condition Approximate Maximum Depth of Fill (feet) Approximate Depth of Fill Differential (feet) Expansion Index Recommended Foundation Category R-8 Fill 31 14 43 II 1 Fill 29 14 35 II 2 Fill 31 15 42 II 3 Fill 32 16 42 II 4 Fill 33 9 42 II 5 Fill 34 15 42 II 6 Fill 20 7 30 II 7 Fill 22 7 42 II 8 Fill 15 1 42 I 9 Fill 24 7 30 II 10 Fill 17 1 21 I 11 Fill 24 4 21 II 12 Fill 26 2 36 II 13 Fill 24 9 36 II 14 Fill 15 2 26 I 15 Fill 16 1 26 I 16 Fill 15 1 25 I 17 Fill 15 1 25 I