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HomeMy WebLinkAboutSDP 14-01; Burke Carlsbad Business Center; Site Development Plan (SDP) (3)13^ ) /^y GEOCON INCORPORATED GEOTECHNICAL ENVIRONMENTAL MATERIALS DUE DILIGENCE UPDATE GEOTECHNICAL REPORT CARLSBAD RACEWAY BUSINESS PARK - LOT 17 CARLSBAD, CALIFORNIA RECEIVED JAN 0 6 2014 CITY OF CARLSBAD PLANNING DIVISION PREPARED FOR AETHERCOMM, INC. CARLSBAD, CALIFORNIA OCTOBER 6, 2010 PROJECT 07349-42-11 GEOCON INCOHPC HATED GEOTECHNICAL • ENVIRONMENTAL • MATERIALS Project No. 07349-42-11 October 6,2010 Aethercoinm, Inc. 3205 Lionshead Avenue Carlsbad, Califomia 92010 Attention: Mr. Richard Martinez Subject: CARLSBAD RACEWAY BUSINESS PARK - LOT 17 CARLSBAD, CALIFORNIA DUE DILIGENCE UPDATE GEOTECHNICAL REPORT Dear Mr. Martinez: In accordance with your request, we have prepared this update geotechnical report to provide recommendations pertinent to development of Lot 17 located within the Carlsbad Raceway Business Park in Carlsbad, Califomia. Geocon provided testing and observation services during original grading of the overall Carlsbad Raceway Business Park. Subsequent to the grading Opus West purchased several lots within the development. It is unknown if additional grading occurred on Lot 17 subsequent to the original grading observed by Geocon Incorporated. The site is underlain by compacted fill overlying the Santiago Formation. Based on our review of available grading reports and the results of our recent field investigation and laboratory testing, it is our opinion the soils underlying Lot 17 are suitable for support of additional fill and/or stmctural loads and fbture development. The accompanying report describes the existing as-graded soil and geologic conditions and provides grading recommendations and foundation design criteria for new development. Should you have questions regarding this update, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Trevor E. Myers RCE 63773 ) Rodney C. Mikesell GE 2533 Garr^;' W. Can CEG2201 RCE 56468 lion TEM:RCM:dmc (6/del) Addressee 6960 Flanders Df.ve • San Diego, California 921 ? 1-2974 • Telephone 858 558.6900 • Fax 858.558 6159 TABLE OF CONTENTS 1. PURPOSE AND SCOPE 1 2. SITE AND PROJECT DESCRIPTION 1 2.1 Proposed Site Development 2 3. SOIL AND GEOLOGIC CONDITIONS 2 3.1 Compacted Fill (Qcf) 3 3.2 Santiago Formation (Ts) 3 4. GROUNDWATER 3 5. GEOLOGIC HAZARDS 4 5.1 Faulting and Seismicity 4 5.2 Liquefaction 6 5.3 Ground Rupture 6 5.4 Landslides 7 5.5 Seiches and Tsunamis 7 6. CONCLUSIONS AND RECOMMENDATIONS 8 6.1 General 8 6.2 Grading 9 6.3 Seismic Design Criteria 11 6.4 Foundations 11 6.5 Concrete Slabs-on-Grade 12 6.6 Retaining Walls 14 6.7 Lateral Loading 15 6.8 Preliminary Pavement Recommendations 15 6.9 Detention Basin and Bioswale Recommendations 17 6.10 Site Drainage and Moisture Protection 18 6.11 Grading and Foundation Plan Review 18 LIMITATIONS AND UNIFORMITY OF CONDITIONS MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2, Geologic Map Figure 3, Wall/Colum Footing Dimension Detail Figure 4, Typical Retaining Wall Drain Detail APPENDIX A FIELD INVESTIGATION Figures A-1 - A-6, Logs of Borings APPENDIX B LABORATORY TESTING Table I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results Table II, Summary of Laboratory Expansion Index Test Results Table III, Summary of Laboratory pH and Resistivity Test Results Table IV, Summary of Laboratory Sulfate Content Test Results Figure B-1, Laboratory Consolidation Curves APPENDIX C RECOMMENDED GRADING SPECIFICATIONS DUE DILIGENCE UPDATE GEOTECHNICAL REPORT 1. PURPOSE AND SCOPE This report presents the results of an update geotechnical study for the proposed development of the Carlsbad Raceway Business Park, Lot 17 of Tract C. T. 98-10. The site is located on Lionshead Avenue, between Melrose Drive and Business Park Drive in Carlsbad, Califomia (see Vicinity Map, Figure 1). The purpose of this due diligence update report is to assess the suitability of existing soils for support of new improvements and to provide recommendations for continued development of the lot. Our scope of work consisted of: Reviewing previously submitted as-graded reports for the site and vicinity. Drilling 6 exploratory borings at the site to observe and sample the subsurface geologic units. Laboratory testing of representative soil sample collected during the subsurface investigation. Providing an updated geologic map of the site. Providing this report. The scope of this study included a review of the following: • Final Report of Testing and Obsermtion Service.^ During Site Grading [for] Carlsbad Raceway Business Park, Lots I Through 28. Tract CT. 98-10, Carlsbad, California, prepared by Geocon Incorporated, dated June 5, 2006 (Project No. 07349-42-02). • Update Geotechnical Report, Opus Pointe at the Raceway, Lots 5 Through 11 (Inclusive) and Lots 16 Through 25 (Inclusive), CT. 98-10, Carlsbad, California, prepared by Geocon Incorporated, dated November 10, 2005 (Project No. 07349-42-06). • Fault Hazard Evaluation, Carlsbad Raceway Business Park, CT. 98-10, Carlsbad, California, prepared by Geocon Incorporated, dated March 1, 2005 (Project No. 07349-42- 02). 2. SITE AND PROJECT DESCRIPTION 2.1 Previous Site Development The project site is located on Lionshead Avenue east of Melrose Drive, west of Business Park Drive, and north of Palomar Airport Road in Carlsbad, Califomia. Lot 17 is part of the overall Carlsbad Raceway Business Park that was graded as a continuous operation between August 2004 and May 2006. Compaction test results and professional opinions pertaining to the original mass grading are summarized in Geocon's above-referenced 2006 report. Original grading for Lot 17 resulted in a sheet-graded lot with fill thickness ranging between 21 to 54 feet. Project No. 07349-42-11 - 1 - October 6, 2010 During original grading, unsuitable material was removed to expose the underlying Santiago formation. A canyon subdrain was installed along the axis of the westerly draining canyon. As indicated by test results and observations, fill soils placed during grading were compacted to at least 90 percent relative compaction at the locations tested. Several lots, including Lot 17, were sold to Opus West subsequent to mass grading. Geocon Incorporated prepared an update geotechnical report for Opus West (see referenced 2005 report). Geocon Incorporated was not retained to provide follow-up geotechnical services for continued development of the lots. Additional grading, if any, that occurred on Lot 17 was not observed and tested by Geocon Incorporated. Lot 17 was utilized as a stockpile area for excess spoils during regrading of the lots purchased by Opus West. The existing property is covered with dirt and minor amount of weed growth. Recently, the soil stockpile was exported from the site. A desilting basin is present in the northwest comer of the site. Utility easements exist along the west and north sides of the site. A building has been constructed on the adjacent lot to the west (Lot 18). Lot 16 to the east is vacant. 2.1 Proposed Site Development Site plans were not available for our review at the time this report was prepared. However, we understand the project may consist of a commercial and/or light industrial stmcture with associated paved parking lots and drive areas, similar to existing buildings in the area. The stmcture will likely be one or two story concrete tilt up constmction with roll up metal doors for vehicle access. We expect minor cuts and fills on the order of 3 feet or less from current sheet grade elevations to constmct a level building pad. The locations and descriptions of the site and proposed development are based on our field observations and our understanding of project development. If project details vary significantly from those described above, Geocon Incorporated should be contacted to determine the necessity for review and revision of this report. 3. SOIL AND GEOLOGIC CONDITIONS In general, the near surface fill soils are composed of silty to clayey fill soils exhibiting a "low" to "medium" (expansion index less than 90) expansion potential. Additionally, soluble sulfate testing on near surface soil samples indicates a "severe" condition. Lot 17 is underlain by compacted fill that could range from approximately 20 feet to 55 feet in depth. Bedrock underlying Lot 17 is comprised of Eocene-age Santiago Fonnation. Compacted fills are composed of soil generated from excavations in alluvium (canyon cleanouts), and excavation of Project No. 07349-42-11 - 2 - October 6, 2010 fonnational soils. The distribution of the geologic units and mapped geologic contacts for the as- graded conditions are depicted in the referenced as-graded geotechnical report and Figure 2 of this report. Sheet grade elevations shown on Figure 2 were taken from sheet grade elevations shown on the original grading plans. We do not know if these elevations match existing sheet grade elevations. Fill placed and compacted under the observation of Geocon Incorporated and summarized in Geocon's referenced November 2005 update report and 2006 as-graded report were to the sheet grade elevations shown on Figure 2. Site elevations higher than those shown on Figure 2 indicate fills placed after the completion of original grading. Compacted fill and geologic units encountered in our field investigation are described below. 3.1 Compacted Fill (Qcf) Compacted fill placed during grading for the Carlsbad Raceway project exists across Lot 17. Grading for the project was completed in May 2006. Observation and compaction testing services during mass grading were provided by Geocon Incorporated. Mass grading for the site resulted in fills with a maximum thickness of approximately 54 feet. The fill consists predominantly of silty and clayey soil. The fill is considered suitable for support of stmctural improvements. Additional fills subsequent to mass grading may have occurred on Lot 17. The lot was used to stockpile spoils during development of other Lots purchased by Opus West. Geocon Incorporated is not the engineer of record for lots purchased by Opus West, and was not provided with a geotechnical report documenting the placement of compacted fills subsequent to original mass grading. However, based on our recent exploratory borings, the fill on Lot 17 appears to be suitable for support of continued development of the property. 3.2 Santiago Formation (Ts) Dense siltstone and claystone interbedded with fine sand ofthe Santiago Formation are present below the fill soils. Clayey soils generated from this formation generally have a "high" Expansion Index; however, sandy beds possess a 'Very low" expansion potential. Portions of the Santiago Formation (deep cut areas) were found to generally possess a severe potential for soluble sulfate exposure. 4. GROUNDWATER Groundwater was encountered at the bottom of alluvium removals in the westerly drainage where a subdrain was placed. The existing geologic units are susceptible to seepage if irrigated or subjected to poor drainage practices, therefore, seepage may appear in areas which previously were dry. Project No. 07349-42-11 - 3 - October 6, 2010 5. GEOLOGIC HAZARDS 5.1 Faulting and Seismicity A review of the referenced geologic reports and our knowledge of the general area indicate that the site is not underlain by an active fault. An active fault is defined by the California Geological Survey (CGS) as a fault showing evidence for activity within the last 11,000 years. The site is not located within State of Califomia Earthquake Fault Zone. A fault was exposed during previous grading on a cut slope descending from Palomar Airport Road that trended in a northwest-southeast direction toward the project site. Fault trenches were excavated along the projection of the fault to more accurately delineate the fauh. Faults were also exposed during grading on the north facing slopes and on Lots 9 and 11 and extended into Lots 16 and 17. These faults were mapped to trend northerly through the site. Fault traces were located by land survey methods. The Santiago Formation bedrock between the two faults was fractured, and was removed and replaced by a stability fill bounding the south margins of Lots 9 and 11. Older alluvial soils overlying the Santiago Formation were not offset in the fault trenches. Radiocarbon dating and infonnation obtained from fault trenching (see Geocon March 2005) indicate the faults are potentially active or older. The California Geologic Survey does not require building setbacks for potentially active faults. This fault is not considered adverse with respect to proposed site development. According to the computer program EZ-FRISK (Version 7.43), 12 known active faults are located within a search radius of 50 miles from the property. The nearest known active fault is the Rose Canyon Fault, located approximately 9 miles west of the site and is the dominant source of potential ground motion. Earthquakes that might occur on the Rose Canyon Fault Zone or other faults within the southem California and northem Baja Califomia area are potential generators of significant ground motion at the site. The estimated deterministic maximum earthquake magnitude and peak ground acceleration for the Rose Canyon Fault are 7.2 and 0.27g, respectively. Table 5.1.1 lists the estimated maximum earthquake magnitude and peak ground acceleration for the most dominant faults in relationship to the site location. We calculated peak ground acceleration (PGA) using Boore- Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) NGA acceleration-attenuation relationships. Project No. 07349-42-11 - 4 - October 6, 2010 TABLE 5.1.1 DETERMINISTIC SPECTRA SITE PARAMETERS Fault Name Distance from Site (miles) Maximum Earthquake Magnitude (Mw) Peak Ground Acceleration Fault Name Distance from Site (miles) Maximum Earthquake Magnitude (Mw) Boore- Atkinson 2008 (g) Campbell- Bozorgnia 2008 (g) Chiou- Youngs 2008 (g) Rose Canyon 9 7.2 0.26 0.22 0.27 Newport-Inglewood (offshore) 1 1 7.1 0.23 0.19 0.22 Elsinore (Julian) 21 7.1 0.17 0.12 0.13 Elsinore (Temecula) 21 7.1 0.15 0.11 0.10 Coronado Bank 24 7.6 0.18 0.12 0.15 Elsinore (Glen-Ivy) 36 6.8 0.10 0.07 0.06 Earthquake Valley 38 6.5 0.08 0.06 0.04 San Joaquin Hills Thrust 41 6.6 0.08 0.07 0.05 Pales Verdes 42 7.3 O.ll 0.07 0.08 San Jacinto (Anza) 44 7.2 0.10 0.07 0.07 San Jacinto (San Jacinto Valley) 46 6.9 0.09 0.06 0.05 We used the computer program EZ-FRISK to perform a probabilistic seismic hazard analysis. The computer program EZ-FRISK operates under the assumption that the occurrence rate of earthquakes on each mapped Quaternary fault is proportional to the fault's slip rate. The program accounts for earthquake magnitude as a function of fault rupture length, and site acceleration estimates are made using the earthquake magnitude and distance from the site to the rupture zone. The program also accounts for uncertainty in each of following: (1) earthquake magnitude, (2) mpture length for a given magnitude, (3) location of the rupmre zone, (4) maximum possible magnitude of a given earthquake, and (5) acceleration at the site from a given earthquake along each fault. By calculating the expected accelerations from considered earthquake sources, the program calculates the total average annual expected number of occurrences of site acceleration greater than a specified value. We utilized acceleration-attenuation relationships suggested by Boore-Atkinson (2008) NGA USGS, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2008) in the analysis. Table 5.1.2 presents the site-specific probabilistic seismic hazard parameters including acceleration-attenuation relationships and the probability of exceedence. Project No. 07349-42-1 -5-October 6, 2010 TABLE 5.1.2 PROBABILISTIC SEISMIC HAZARD PARAMETERS Probability of Exceedence Peak Ground Acceleration Probability of Exceedence Boore-Atkinson, 2007 (g) Campbell-Bozorgnia, 2008 (g) Chiou-Youngs, 2008 (g) 2% in a 50 Year Period 0.55 0.44 0.52 5% in a 50 Year Period 0.44 0.35 0.40 10% in a 50 Year Period 0.35 0.2S The California Geologic Survey (CGS) has a program that calculates the ground motion for a 10 percent of probability of exceedence in 50 years based on an average of several attenuation relationships. Table 5.1.3 presents the calculated results from the Probabilistic Seismic Hazards Mapping Ground Motion Page from the CGS website. TABLE 5.1.3 PROBABILISTIC SITE PARAMETERS FOR SELECTED FAULTS CALIFORNIA GEOLOGIC SURVEY Calculated Acceleration (g) Firm Rock Calculated Acceleration (g) Soft Rock Calculated Acceleration (g) Alluvium 0.25 0.27 0.31 While listing peak accelerations is useful for comparison of potential effects of fault activity in a region, other considerations are important in seismic design, including the frequency and duration of motion and the soil conditions underlying the site. Seismic design of the stmctures should be evaluated in accordance with the Califomia Building Code (CBC) guidelines currently adopted by the City of Carlsbad. 5.2 Liquefaction Liquefaction typically occurs in cohesionless sands below the water table as a result of rapid pore water pressure increase from earthquake-generated ground accelerations. The risk liquefaction hazard occurring within the site soils is considered to be 'Very low" due to the lack of a near surface permanent groundwater condition and the dense nature of the fonnational and compacted fill soils. 5.3 Ground Rupture The risk associated with ground rupture hazard is very low due to the absence of active faults at the subject site. Project No. 07349-42-11 -6-October6, 2010 5.4 Landslides No evidence of landslides or slope instability were observed on the Lot during previous grading or observed during our recent field investigation. It is our opinion that the risk associated with landslide hazard at the site is low. 5.5 Seiches and Tsunamis The site is located over 5 miles from the coast at an elevation near 400 feet above mean sea level (MSL). Wave heights and mn-up elevations from tsunami along the San Diego Coast have historically fallen within the normal range ofthe tides. The County of San Diego Hazard Mitigation Plan maps zones of high risk for tsunami mn-up for coastal areas diroughout the county. The site is not included in the high-risk hazard area. The site is not located near or downstream of any large body of water. The risk associated with tsunami or seiche hazard is low. Project No. 07349-42-11 - 7 - October 6, 2010 6. CONCLUSIONS AND RECOMMENDATIONS 6.1 General 6.1.1 No soil or geologic conditions were encountered diat, in our opinion, would preclude the continued development of the property as presently planned, provided that the recommendations of this report are followed. 6.1.2 In-place density tests performed during previous mass grading indicate fills were compacted to at least 90 percent relative compaction at the locations tested. The fills are stmcmral and considered suitable for support of additional fill and/or stmctural loading. 6.1.3 Based on field and laboratory studies perfonned for this report, the soils at the site appear to be suitable for support of future development. 6.1.4 The soil encountered in the field investigation has a "medium" expansion potential (expansion index [El] of 90 or less) as defined by 2007 Califomia Building Code (CBC) Section 1802.3.2. Table 6.1.1 presents soil classifications based on the expansion index. The expansion index test results are presented in Appendix B. TABLE 6.1.1 SOIL CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (EI) Soil Classification 0-20 Very Low 21-50 Low 51-90 Medium 91 - 130 High Greater Than 130 Very High 6.1.5 Water-soluble sulfate testing was conducted on samples of the on-site near surface soils to check whether the soils contain high enough sulfate concentrations that could damage normal portland cement concrete. The laboratory test results are summarized in Appendix A. The test results indicate a "severe" sulfate rating based on Table 19-A-4 of the California Building Code (CBC). CBC guidelines should be followed in determining the type of concrete to be used. Table 6.1.2 presents a summary of concrete requirements set forth by CBC Table 19A-A-4. The presence of water-soluble sulfate is not a visually discernible characteristic; therefore, other soil samples from die site could yield different concentrations. Additionally, over time, landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. Representative samples of the finish grade soils should be conducted at the completion of fine grading and additional sulfate Project No. 07349-42-11 October 6, 2010 testing should be perfonned on acmal samples of the materials that will be in contact with concrete. TABLE 6.1.2 REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS (FROM CBC TABLE 19-A-4) Sulfate Exposure Water-Soluble Sulfate Percent by Weight Cement Type Maximum Water to Cement Ratio by Weight Minimum Compressive Strength (psi) Negligible 0.00-0.10 ~ — — Moderate 0.10-0.20 11, IP(MS, IS(MS) 0.50 4.000 Severe 0.20-2.00 V 045 4,500 Very Severe over 2.00 V plus pozzolan 0.45 4,500 6.1.6 Potential-of-hydrogen (pH) and resistivity tests of the near surface soils indicate a pH varying from 8.1 to 8.2 with resistivity varying from 510 to 560 ohm centimeters. The laboratory test results are provided in Appendix A. The low resistivity indicates a corrosive environment that impact buried metal. Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, if improvements that could be susceptible to corrosion are planned, it is recommended that a corrosion specialist be consulted to provide site- specific recommendations. 6.1.7 Additional sampling and testing for expansion index and soluble sulfate content of finish grade soils at building locations should be performed at the completion of fine grading. 6.1.8 Excavation of fill soils should generally be possible with moderate effort using conventional, heavy-duty equipment during grading and trenching operations. Excavations of formational material, if any, will require heavy effort and may generate oversize rock that could require special handling and disposal. 6.2 Grading 6.2.1 All grading should be performed in accordance with the Recommended Grading Specifications in Appendix C. Where the recommendations of this section conflict with those in Appendix C, the recommendations of this section take precedence. All earthwork should be observed and all fills tested for proper compaction by Geocon Incorporated. Project No. 07349-42-11 -9-October 6,2010 6.2.2 Prior to commencing grading, a preconstmction conference should be held at the site with the owner or developer, grading contractor, civil engineer, and geotechnical engineer in attendance. Special soil handling and/or the grading plans can be discussed at that time. 6.2.3 Site preparation should begin with the removal of all deleterious material and vegetation. The depth of removal should be such that material exposed in cut areas or soil to be used as fill is relatively free of organic matter. Material generated during stripping and/or site demolition should be exported from the site. 6.2.4 To prepare the lot for support of stmcmral improvements, we recommend the upper 1-foot of existing soil be removed, moisture conditioned, and recompacted. Prior to placing fill, the upper 1-foot below the removal should be scarified, moisture conditioned to near optimum moisture content, and recompacted. Fill soils may then be placed and compacted to design finish grade elevations. Where cuts in excess of 1 foot are made to achieve pad grade, in-place density tests should be performed at the cut elevation to check the moisture content of soils that will be at building pad grade. Additional removal and recompaction may be required if loose, dry, or otherwise unsuitable soil is encountered at the base of removals. 6.2.5 In the existing desilting basin, all loose/soft soft soil should be removed to expose competent compacted fill. We expect removal deptlis on the order of 2 to 3 feet will be required. The resuhing excavation should be backfilled with compacted fill. 6.2.6 If highly expansive soils are exposed at finish grade, the building pad should be overexcavated at least 3 feet and replaced with "low" to "medium" expansive soil to mitigate adverse conditions from expansive soil movement. 6.2.7 Expansive soils should be placed outside of building pads, preferably in landscape areas, to reduce the potential for distress to buildings and surface improvements. 6.2.8 All fill, including scarified ground surfaces, should be compacted to at least 90 percent of laboratory maximum dry density in accordance with ASTM Test Procedure D 1557-02, at or slightly above optimum moismre content. Fill materials with in-place density test results indicating moisture contents less than optimum will require additional moisture conditioning before placing additional fill. 6.2.9 Imported soil, if required, should consist of granular material with a "low" expansion potential and negligible sulfate rating. Once borrow sites have been identified, soil samples Project No. 07349-42-11 - 10 - October 6, 2010 should be collected and subjected to laboratory testing to verify conformance with the expansion and soluble sulfate criteria. 6.3 Seismic Design Criteria 6.3.1 We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the USGS. Table 6.3 summarizes site-specific design criteria obtained from the 2007 Califomia Building Code (CBC; Based on the 2006 International Building Code [IBC]), Chapter 16 Stmctural Design, Section 1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. TABLE 6.3 2007 CBC SEISMIC DESIGN PARAMETERS Parameter Value IBC-06 Reference Site ( la.ss C Table 1613.5.2 Spectral Response - Class B (short), Ss 1.079g Figure 1613.5(3) Spectral Response - Class B (1 sec), S] 0.409g Figure 1613.5(4) Site Coefficient, FA 1.00 Table 1613.5.3(1) Site Coefficient, Fv 1.591 Table 1613.5.3(2) Maximum Considered Earthquake Spectral Response Acceleration (short), SMS 1.153g Section 1613.5.3 (Eqn 16-37) Maximum Considered Earthquake Spectral Response Acceleration - (1 sec), SMI 0.65 Ig Section 1613.5.3 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (short), SDS 0.769g Section 1613.5.4 (Eqn 16-39) 5% Damped Design Spectral Response Acceleration (1 sec), Spi 0.434g Section 1613.5.4 (Eqn 16-40) 6.3.2 Conformance to the criteria in Table 6.3 for seismic design does not constitute any kind of guarantee or assurance that significant stmctural damage or ground failure will not occur if a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid all damage, since such design may be economically prohibitive. 6.4 Foundations 6.4.1 The proposed stmcture can be supported on a shallow foundation system foimded in compacted fill. Foundations for the stmcmre should consist of continuous strip footings and/or isolated spread footings. Continuous footings should be at least 12 inches wide and extend at least 24 inches below lowest adjacent pad grade. Isolated spread footings should have a tninimum width of 2 feet and should also extend at least 24 inches below lowest Project No. 07349-42-1 - 11 -October 6, 2010 adjacent pad grade. Concrete reinforcement for continuous footings should consist of at least four. No. 5 steel bars placed horizontally in the footings, two near the top and two near die bottom. The project stmcmral engineer should design the concrete reinforcement for the spread footings. A footing dimension detail is presented in Figure 2. 6.4.2 The minimum reinforcement recommended herein is based on soil characteristics only (Fl of 90 or less) and is not intended to replace reinforcement required for stmctural considerations. 6.4.3 The recommended allowable bearing capacity for foundations with minimum dimensions described herein is 2,000 pounds per square foot (psf)- llie allowable soil bearing pressure may be increased by an additional 300 psf and 500 psf for each additional foot of foundation width and depth, respectively, to a maximum allowable bearing capacity of 4,000 psf. The values presented herein are for dead plus live loads and may be increased by one-third when considering transient loads due to wind or seismic forces. 6.4.4 Settlement due to footing loads conforming to the above recommended allowable soil bearing pressures are expected to be less than 1-inch total and ^/4-inch differential over a span of 40 feet. 6.4.5 Footings should not be located within 7 feet of the tops of slopes. Footings that must be located within this zone should be extended in depth such that the outer bottom edge of the footing is at least 7 feet horizontally from the face of the finished slope. 6.4.6 No special subgrade presaturation is deemed necessary prior to placement of concTcte. However, the slab and foundation subgrade should be sprinkled as necessary to maintain a moist condition as would be expected in any concrete placement. 6.4.7 Foundation excavations should be observed by a representative of Geocon Incorporated prior to the placement of reinforcing steel and concrete to check that the exposed soil conditions are consistent with those anticipated and have been extended to appropriate bearing strata. If unexpected soil conditions are encountered, foundation modifications may be required. 6.5 Concrete Slabs-on-Grade 6.5.1 Interior concrete slabs-on-grade should be at least 5 inches thick. Point loads or line loads from forklifts, other equipment or stmctures should be considered during stmctural design of the slabs-on-grade. Minimum slab reinforcement should consist of No. 3 steel Project No. 07349-42- II - 12 - October 6, 2010 reinforcing bars placed 18 inches on center in both horizontal directions and positioned near the slab midpoint. 6.5.2 Concrete slabs on grade should be imderlain by 4 inches of clean sand to reduce the potential for differential curing, slab curl, and cracking. Slabs that may receive moisture- sensitive floor coverings or may be used to store moisture-sensitive materials should be underlain by a vapor retarder placed in the middle of the sand layer. The project architect should specify the type of vapor retarder used based on the type of floor covering that will be installed. The vapor retarder design should be consistent with the guidelines presented in Section 9.3 of the American Concrete Institute's (ACI) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06). 6.5.3 All exterior concrete flatwork not subject to vehicular traffic should be constmcted in accordance with the following recommendations. Slab panels in excess of eight feet square should be reinforced with No. 3 steel bars spaced 24 inches center to center and positioned near the middle of the slab. All concrete flatwork should be provided with crack control joints to reduce and/or control shrinkage cracking. The project stmctural engineer should determine crack control spacing 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 soils for exterior slabs not subjected to vehicle loads should be compacted to at least 90 percent of the maximum dry density at near- optimum moisture content. 6.5.4 Where exterior flatworic abuts the stmcmre at entrance or exit areas, the exterior slab should be dowelled into the foundation stemwall. This recommendation is intended to reduce the potential for differential elevations that could resuh from differential settlement or minor heave of the flatwoilc. Consideration should also be given to doweling sidewalks to curbs to reduce potential off-set as a result of heave or settlement. The project stmctural engineer should provide dowelling details. 6.5.5 The above slab-on-grade dimensions and minimum reinforcement recommendations are based upon soil conditions only and are not intended to be used in lieu of those required for stmctural purposes. 6.5.6 The recommendations of this report are intended to reduce the potential for cracking of slabs due to differential settlement of fills of varying thickness and expansive soils. However, even widi the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such soil conditions may exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete Project No. 07349-42-11 - 13 - October 6, 2010 shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by: (1) limiting the slump ofthe concrete, (2) proper concrete placement and curing, and (3) by the placement of crack-control joints at periodic intervals, particularly where re-entrant slab corners occur. 6.5.7 Geocon Incorporated should be consulted to provide additional design parameters as required by the strucmral engineer. 6.6 Retaining Walls 6.6.1 Retaining walls that are allowed to rotate more than 0.001 H (where H equals the height of the retaining portion of the wall) at the top of the wall, 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 2:1 (horizontakvertical), an active soil pressure of 50 pcf is recommoided. Soil with an expansion index (EI) of greater than 50 should not be used as backfill material behind retaining walls. 6.6.2 Where walls are resfrained from movement at the top, an additional uniform pressure of 7H psf should be added to the 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. 6.6.3 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 recommendations herein assume a properly compacted granular (EI of 50 or less) free-draining backfill material with no hydrostatic forces or imposed surcharge load. Figure 3 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. 6.6.4 The stmctural engineer should detennine die seismic design category for the project and if retaining walls need to incorporate seismic lateral loads. A seismic load of 18H should be used for design. 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 top of the wall and zero at the base of the wall. We used a peak site acceleration of 0.3Ig calculated using SDS/2.5 USGS and applying a pseudo-static coefficient of 0.5. Project No. 07349-42-11 - 14 - October 6, 2010 6.6.5 In general, shallow conventional wall footings founded in properly compacted fill or fonnational materials and having a minimum depth and width of one foot may be designed for an allowable soil bearing pressure of 2,000 psf, provided the soil within 5 feet below the base of the wall has been properly compacted during remedial grading and possess 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 consuUed where such a condition is anticipated. 6.7 Lateral Loading 6.7.1 To resist lateral loads, a passive pressure exerted by an equivalent fluid density of 300 pounds per cubic foot (pcf) should be used for the design of footings or shear keys. The allowable 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. 6.7.2 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. 6.8 Preliminary Pavement Recommendations 6.8.1 The following recommendations are provided for preliminary design purposes. Final pavement section design will depend upon soil conditions exposed at subgrade elevation and results of Resistance Value (R-Value) tests perfonned on samples of actual subgrade soils. The preliminary pavement section recommendations are based on an R-value of 12 (average value obtained from 13 subgrade soil samples collected in Lionshead Drive, Eagle Drive, and Melrose Drive). Asphalt concrete sections are based on the City of Carlsbad Structural Sections of Streets and Alley, Supplemental Standard GS-17 and the Caltrans Highway Design Manual. We calculated the rigid pavement section in general confonnance with the procedure recommended by the American Concrete Institute report ACI 330R-08 Guide for Design and Construction of Concrete Parking Lots. Project No. 07349-42-11 - 15 - October 6, 2010 TABLE 6.8 PRELIMINARY PAVEMENT DESIGN SECTIONS Location Assumed Traffic Index (TI) Asphah Concrete Portland Cement Concrete Location Assumed Traffic Index (TI) Asphalt Concrete (inches) Class 2 Base (inches) Concrete (inches) Class 2 Base (inches) Automobile Parking 4.5 4 4 5 0 Automobile Driveways 5 4 6.5 5.5 4 Heavy Truck Area 6 4 12.5 6 6.8.2 Samples of pavement subgrade should be collected prior to placement of base and asphalt for laboratory testing to aid in evaluation of the preliminary flexible pavement sections. Additional pavement recommendations may be forthcoming depending upon laboratory tests of the exposed subgrade. 6.8.3 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public Works Construction (Green Book). Class 2 aggregate base materials should conform to Section 26-1.02A ofthe Standard Specifications ofthe State of Califomia, Department of Transportation (Caltrans). 6.8.4 Prior to placing base material, the upper 12 inches of subgrade should be scarified, moisture conditioned and compacted to a minimum of 95 percent of the maximum dry density as determined by ASTM D 1557-02. The base material should be compacted to at least 95 percent relative compaction. Asphalt concrete should be compacted to a minimum of 95 percent of the laboratory Hveem density. 6.8.5 The performance of pavements is highly dependent upon providing positive surface drainage away from the edge of pavements. Ponding of water on or adjacent to pavements will likely result in samration of the subgrade materials and subsequent pavement distress. If planter islands are planned, the perimeter curb should extend at least 6 inches below the bottom of the Class 2 aggregate base. 6.8.6 Loading aprons such as trash bin enclosures and loading docks should utilize portland cement concrete as recommended above for tmck traffic areas. The pavement should be at least 6 inches thick and reinforced widi No. 3 steel reinforcing bars spaced 18 inches on center in both directions placed at the slab midpoint. The concrete should extend out from the loading dock or trash bin such that botii the front and rear wheels of the truck will be located on reinforced concrete pavement when loading. Project No. 07349-42-11 - 16-October 6, 2010 6.8.7 The following recommendations are being provided for portland cement concrete pavement areas. The project stmctural engineer should provide reinforcement for the concrete slabs. • The Portland cement concrete pavement sections in Table 6.8 are based on a minimum concrete flexural strength (modulus of mpture, MR) of 500 pounds per square inch (psi) (compressive strength of 3,200 psi), a modulus of subgrade reaction, k, of 100 pounds per cubic inch (pci), fraffic category "A" for automobiles and traffic category "B" for heavy tmck traffic assuming an average daily tmck traffic of 25 or less. Geocon Incorporated should be contacted for possible revisions to the pavement design sections if these design parameters are not conect. • A thickened edge or integral curb should be constructed on the outside of concrete slabs subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness at the slab edge and taper to the recommended slab thickness 3 feet behind the face of the slab (e.g., an 8-inch-thick slab would have a 9.6-inch-thick edge). • To control the location and spread of concrete shrinkage cracks, it is recommended that crack control joints be included in the design of the concrete pavement slab. Crack control joint spacing should not exceed, in feet, twice the recommended slab thickness in inches (e.g., 16 by 16 feet for an 8-inch-thick slab). The crack-control joints should be created while the concrete is still fresh using a grooving tool, or shortly thereafter using saw cuts. The joint should extend into the slab a minimum of one-fourth of the slab thickness. • Construction joints should be provided at the interface between areas of concrete placed at different times during constmction. Doweling is recommended between the joints to transfer anticipated tmck traffic loading. Dowels should be located at the midpoint ofthe slab and be spaced at 12 inches on center. As an alternative to doweling, a keyway may be used to transfer wheel loads. The keyway should have a width of 0.2 times the slab thickness and a depth equal to 0.1 times the slab thickness (e.g., for a 7-inch-thick slab, the keyway would have a width of approximately 1.4 inches and a depth of 0.7 inches). The project stmctural engineer should provide alternative recommendations for load transfer. • Consideration should be given to the use of a crack-control joint and expansion joint filler or sealer to aid in preventing migration of water into subgrade and base materials. Appropriate fillers or sealers are discussed in section 7.3 of the referenced ACI guide. 6.9 Detention Basin and Bioswale Recommendations 6.9.1 Any 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 drain pipe. The Project No. 07349-42-11 - 17 - October 6, 2010 concrete cut-off wall should extend at least 6-inches beyond the perimeter of the gravel- packed subdrain system. 6.9.2 Distress may be caused to plaimed improvements and properties located hydrologically downstream or adjacent to these devices. The distress depends on the amoimt of water to be detained, its residence time, soil penneability, 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 infilfration. Due to site soil and geologic conditions, bioswales and bio-remediation areas should be lined with an impenneable barrier, such as a thick visqueen, to prevent water infiltration in to the underlying compacted fill. 6.9.3 The landscape architect should be consulted to provide the appropriate plant recommendations. If drought resistant plants are not used, irrigation may be required. 6.10 Site Drainage and Moisture Protection 6.10.1 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 stmcmres in accordance with 2007 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 cany mnoff away from the proposed stmcture. 6.10.2 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. 6.10.3 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. 6.11 Grading and Foundation Plan Review 6.11.1 Geocon Incorporated should review the grading plans and foundation plans for die project prior to final design submittal to evaluate whether additional analyses and/or recommendations are required. Project No. 07349-42-11 - 18 - October 6, 2010 LIMrrATIONS AND UNIFORMITY OF CONDITIONS 1. The recommendations of this report pertain only to the site investigated and are based upon the assumption that the soil conditions do not deviate from those disclosed in the investigation. If any variations or undesirable conditions are encountered during constmction, or if die proposed constmction will differ from that anticipated herein, Geocon Incorporated should be notified so that supplemental recommendations can be given. The evaluation or identification ofthe potential presence of hazardous or conosive materials was not part of the scope of services provided by Geocon Incorporated. 2. This report is issued with the understanding that it is the responsibility of the owner or his representative to ensure that the information and recommendations contained herein are brought to the attention of the architect and engineer for the project and 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. 3. The findings of this report are valid as of the present date. However, changes in the conditions of a property can occur with the passage of time, whether due to natural processes or the works of man on this or adjacent properties. In addition, changes in applicable or appropriate standards may occur, whether they result from legislation or the broadening of knowledge. Accordingly, the findings 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. 4. The firm that perfonned the geotechnical investigation for the project should be retained to provide testing and observation services during constmction to provide continuity of geotechnical interpretation and to check that the recommendations presented for geotechnical aspects of site development are incorporated during site grading, constmction of improvements, and excavation of foundations. If another geotechnical firm is selected to perform the testing and observation services during constmction operations, that firm should prepare a letter indicating their intent to assume the responsibilities of project geotechnical engineer of record. A copy ofthe letter should be provided to the regulatory agency for their records. In addition, that firm should provide revised recommendations conceming the geotechnical aspects of the proposed development, or a written acknowledgement of their concunence with the recommendations presented in our report. They should also perform additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record. Project No. 07349-42-11 October 6, 2010 THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH. SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT OF SUCH USE OR RELIANCE BY CLIENT. NO SCALE GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 TR/AML DSK/GTYPD VICINITY MAP CARLSBAD RACEWAY - LOT 17 CARLSBAD, CALIFORNIA DATE 10-06-2010 PROJECT NO. 07349 - 42 - 11 FIG. 1 Vicintfy Map CARLSBAD RACEWAY - LOT 17 CARLSBAD, CALIFORNIA SCALE: r = 60- GEOCON LEGEND ..COMPACTED FILL ^ * TSd SANTIAGO FORMATK3N (Dolled Where Suited) • APPROX. LOCATION OF EXPLORATORY BORING APPROX LOCATION OF FAULT APPROX. LOCATION OF SUBORAM .A. APPROX. ELEVATION OF SUBDRAIN I , BE] APPROX. ELEVATION AT BOTTOM OF NATIVE SOIL REMOVAL GEOCON INCOIlPOnATED GfOTEQINCAl CONSUITANTS 6960 FLAM3WS DSIVt - SAN tXGO, C»UfOSMA 92131 - 2974 PHOrC 858 Si»-tiVO0 - FAX US iiH)\59 PROJECT NO. 07349 • 42 - 11 SITE PLAN DATE 10-06-2010 CONCRETE Sl-AB SAND MOISTURE INHIBITOR (WHERE REQUIRED) ..v-fV .... ...-^ .. ''<'K.^33^' FOOTING* WIDTH PAD GRADE il K Q. O O D -I V CONCRETE SLAB SAND MOISTURE INHIBITOR (WHERE REQUIRED) ...X.. ..V. 1)1 : .V- ..v:..-- ......^. " - • : - v. P .•.4v; VI' J.' . . . V.^. •i' , ^ .... •»•. • FOOTING WIDTH- ....SEE REPORT FOR FOUNDATION WITDH AND DEPTH RECOMMENDATION NO SCALE WALL / COLUMN FOOTING DIMENSION DETAIL GEOCON ^ INCORPORATED ^^V^ GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 CARLSBAD RACEWAY - LOT 17 CARLSBAD, CALIFORNIA AS/AML j DSK/GTYPD DATE 10-06-2010 PROJECT NO. 07349-42- 11 | FIG. 3 COLFOOI2DWG GROUND SURFACE CONCRETE BROWDITCH PROPOSED RETAINING WALL TEMPORARY BACKCUT PER OSHA GROUND SURFACE MIRAFI 140N FILTER FABRIC (OR EQUIVALENT) OPEN GRADED r MAX. AGGREGATE 4- DIA. PERFORATED SCHEDULE 40 PVC PIPE EXTENDED TO APPROVED OUTLET GROUND SURFACE CONCRETE BROWDITCH WATER PROOFING PER ARCHITECT DRAINAGE PANEL (MIF?ADRAIN 6000 OR EQUIVALENT) 3/4" CRUSHED ROCK (1 CU.FT./FT.) FILTER FABRIC ENVELOPE MIRAFI HON OR EQUIVALENT 4- DIA. SCHEDULE 40 PERFORATED PVC PIPE OR APPROVED TOTAL DRAIN EXTENDED TO APPROVED OUTLET FOOTING DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING TYPICAL RETAINING WALL DRAIN DETAIL GEOCON INCORPORATED GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 TR/RA DSK/GTYPD CARLSBAD RACEWAY - LOT 17 CARLSBAD, CALIFORNIA DATE 10-06-2010 I PROJECT NO, 07349 - 42 - 11 I FIG. 4 APPENDIX APPENDIX A FIELD INVESTIGATION The field investigation was perfonned on September 15, 2010, and consisted of drilling six small- diameter borings at the approximate locations shown on Figure 2. The borings were drilled to a maximum depth of 19.5 feet below existing grade using a CME-55 truck-mounted drill rig equipped with 8-inch-diameter hollow-stem augers. Relatively undisturbed samples were obtained with the drill rig by driving a 3-inch O. D., split-Uibe sampler 12 inches into the undismrbed soil mass with blows from a 140-pound hammer falling 30 inches. The split-tube sampler was equipped with 1-inch- high by 2/4-inch-diameter brass sampler rings to facilitate sample removal and testing. The soil conditions encountered in the borings were visually examined, classified and logged in general confonnance with the American Society for Testing and Materials (ASTNf) Practice for Description and Identification of Soils (Visual-Manual Procedure D2488). The logs of the exploratory borings are presented on Figures A-1 through A-6. The logs depict the various soil types encountered and indicate the depths at which samples were obtained. Project No. 07349-42-11 October 6. 2010 PROJECT NO. 07349-42-11 DEPTH IN FEET SAMPLE NO. SOIL CLASS (USCS) BORING B 1 ELEV. (MSL.) DATE COMPLETED 09-15-2010 EQUIPMENT CME55 BY: T. MYERS 2oi-b z y- LI. I— > I- CO > >- CO ^ z u- °^ Q UJ £\ o z 5 O O - 0 - 2 MATERIAL DESCRIPTION Bl-I - Bl-2 - 4 - - 6 - - 8 - 10 - 12 - - 14 - 16 - 18 - Bl-3 Bl-4 Bl-5 Bl-6 Bl-7 ML CL sc (1. ML COMPACTED FILL Stiff, damp, light brown. Clayey SILT with fine sand and gravel -Very stiff, moist, orangish brown and gray. Clayey SILT with some fme sand and gravel -Very stiff, moist, yellowish brown to white. Clayey SILT with fine sand and gravel - 39 11 116.9 120.2 Very stiff, moist, mottled dark brown, gray, Sandy CLAY with siU _2a Medium dense, moist, mottled, yellowish brown, white and orange. Clayey, fine SAND Stiff, moist, mottled, orange brown, olive brown, gray, Silty CLAY with some fine to medium sand 1(1 -Very stiff, moist, mottled dark brown, orange and gray, Silty CLAY with some fme to medium sand Very stiff, moist, mottled orange brown, brown, white. Clayey SILT with some fme to medium sand 78/5' 13.1 12.9 BORING TERMINATED AT 19.9 FEET No groundwater encountered Figure A-1, 07349-42-11.GPJ Log of Boring B 1, Page 1 of 1 D - SAMPLING UNSUCCESSFUL I] ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED) SAMPLE SYMBOLS I] ... STANDARD PENETRATION TEST 1 ... DRIVE SAMPLE (UNDISTURBED) ^ ... DISTURBED OR BAG SAMPLE B ...CHUNK SAMPLE 5 ... WATER TABLE OR SEEPAGE NOTE THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED, rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDDTONS AT OTHER LCXATIONS AND TIMES. GEOCON PROJECT NO. 07349-42-11 DEPTH IN FEET SAMPLE NO. SOIL CLASS (USCS) BORING B 2 ELEV. (MSL.) DATE COMPLETED 09-15-2010 EQUIPMENT CME55 BY: T. MYERS 2oi- t: 2 y; I- CO > CO ^ z u- u cc Q o z 2 o o MATERIAL DESCRIPTION - 0 - 2 - 6 - - 10 - - 12 - - 14 - 16 - - M B2-1 B2-2 B2-3 B2-4 B2-5 B2-6 B2-7 ML-CL SM ML SM Sf CL SM" CL sc" COMPACTED FILL Medium stiff damp, yellowish brown to dark brown. Sandy SILT and Silty CLAY _ 44 Medium dense, moist, orange brown, fine to medium Silly SAND -Dense, moist, yellow brown and orange brown, fme to coarse Silty SAND with gravel Very stiff, moist, orange brown, Sandy SILT with some clay -Very stiff moist, yellow brown and gray. Clayey SILT with some fme to medium sand _ 42 Medium dense, moist, yellowish brown, orange brown and gray. SiUy, fine to medium SAND 38 Medium dense, moist, orange brown. Clayey SAND Stiff moist, gray, Silty CLAY Medium dense, moist, orange brown and gray, Silty, fine to medium SAND 3.^ Stiff, moist, dark brown to dark gray, Silty CLAY Medium dense, moist, orange brown, Clayey, fine to medium SAND BORING TERMINATED AT 19.9 FEET No groundwater encountered 114.0 116.4 16.3 15.3 Figure A-2, Log of Boring B 2, Page 1 of 1 07349-42-11.GPJ ^ „ D - SAMPLING UNSUCCESSFUL SAMPLE SYMBOLS ^ ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST S ... CHUNK SAMPLE 1 ... DRIVE SAMPLE (UNDISTURBED) J ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONOmONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. mS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07349-42-11 DEPTH IN FEET SAMPLE NO. SOIL CLASS (USCS) BORING B 3 ELEV. (MSL.) DATE COMPLETED 09-15-2010 EQUIPMENT CME55 BY: T. MYERS b: z y- I- CO > i^JoO ;UJ: CO '~. Z U- > cc n Q- - 0 MATERIAL DESCRIPTION B3-1 - 2 - - B3-2 - 4 - - 6 - 10 - 12 - - 14 - 16 - - 18 - B3-3 B3-4 B3-5 B3-6 B3-7 CL SM ML SM CL ML COMPACTED FILL Stiff damp to slightly moist. Silty CLAY Medium dense, moist, mottled orange brown and white, Silty, fme to medium SAND; rock in shoe -Medium dense, moist, orange brown, Silty, fine SAND Stiff, moist, olive brown, Clayey SILT Medium dense, moist, orange brown and yellow brown, Silty. fine SAND - 54 43 32 Very stiff, moist, gray, Silty CLAY with some fine to coarse sand 37 Very stiff, moist, olive brown and gray. Clayey SILT with some sand 114.8 108.1 16.5 19.5 BORING TERMINATED AT 19.9 FEET No groundwater encountered Figure A-3, Log of Boring B 3, Page 1 of 1 07349-42-11.GPJ D ••• SAMPLING UNSUCCESSFUL SAMPLE SYMBOLS ^ ... DISTURBED OR BAG SAMPLE H ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE 1 ... DRIVE SAMPLE (UNDISTURBED) I ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED, rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDmONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07349-42-11 DEPTH IN FEET SAMPLE NO. SOIL CLASS (USCS) BORING B 4 ELEV. (MSL.) DATE COMPLETED 09-15-2010 EQUIPMENT CME55 BY: T. MYERS H CO > LU UJ CO CL tr CO -T Z LJ- 01 Q UJ O Z 5 O O MATERIAL DESCRIPTION - 0 - 2 - - 4 - 6 - - 10 - 12 - 14 - - 16 - - 18 - B4-1 B4-2 B4-3 B4-4 B4-5 CL SM 7 , //I B4-6 B4-7 CL ivir CL-ML ML COMPACTED FILL Stiff, damp to slightly moist, olive brown, Silty CLAY Medium dense, moist, yellow brown and gray brown, Silty, fine to coarse SAND with gravel; sample disturbed -Medium dense, moist, mottled orange brown, gray, white, Silty, fine lo medium SAND with some clay -78/1 r 14 _22 111.5 113.0 Stiff, moist, dark olive brown, fine to coarse Sandy CLAY Stifi". moist, mottled gray, orange brciwn, white, Sandy SILT with little clay ,5: Very stiff, moist, dark brown, Silty CLAY and orange brown. Clayey SILT 2') Stiff, slightly moist, mottled yellow brown, orange brown, gray and white, fine Sandy SILT -Stiff, moist, mottled yellow brown, orange brown, white. Clayey SILT VI 17.4 17.8 BORING TERMINATED AT 19.9 FEET No groundwater encountered Figure A-4, Log of Boring B 4, Page 1 of 1 07349-42-11.GPJ 0 •• SAMPLING UNSUCCESSFUL SAMPLE SYMBOLS ^ ... DISTURBED OR BAG SAMPLE H ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE 1 .. DRIVE SAMPLE (UNDISTURBED) ^ ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED, IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONOmONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07349-42-11 DEPTH IN FEET SAMPLE NO. SOIL CLASS (USCS) BORING B 5 ELEV. (MSL.) DATE COMPLETED 09-15-2010 EQUIPMENT CME55 BY: T. MYERS b 2 LL I- CO > CO T Z li- cc Q O Z 5 O o MATERIAL DESCRIPTION B5-1 - B5-2 ML • - 4 - - 6 - - 10 - B5-3 B5-4 B5-5 CL ( 1.-.\1L ML SM ML rOMP.\CTED FILL Stiff, damp to slightly moist. Clayey SILT with some sand Hard, moist, orange brown and gray, Silty CLAY with some fine to coarse sand _ 48 123.1 Stiff, moist, olive brown to dark brown, Silty CLAY and Clayey SILT with some sand 30 -41 114.1 Very stiff, moist, greenish brown and orange brown. Clayey SILT; sample disOirbed duejopvcpipe_ _ j Dense, moist, yellow brown, Silty, fine to coarse SAND Very stiff, moist, mottled gray, olive brown, orange brown. Clayey SILT with some sand / BORING TERMINATED AT 11 FEET No groundwater encountered 34 12.4 17.3 Figure A-5, Log of Boring B 5, Page 1 of 1 07349-42-11.GPJ D •• SAMPLING UNSUCCESSFUL SAMPLE SYMBOLS S • DISTURBED OR BAG SAMPLE |] ... STANDARD PENETRATION TEST B ...CHUNK SAMPLE 1 ... DRIVE SAMPLE (UNDISTURBED) I ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED, rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONOmONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. 07349-42-11 DEPTH IN FEET SAMPLE NO. SOIL CLASS (USCS) BORING B 6 ELEV. (MSL.) DATE COMPLETED 09-15-2010 EQUIPMENT CME55 BY: T. MYERS 2 oi- I- CO > ^cog CO ^ Z LL u CL Q UJ ^\ o z 2 O o MATERIAL DESCRIPTION - 0 B6-1 - 2 - - B6-2 - 4 - - 6 - ML-CL COMPACTED FILL Stiff damp to slightly moist, dark yellowish brown. Clayey SILT and Silty CLAY -42, LLL5 1Z9- - SM - 10 - B6-3 B6-4 B6-5 ML Dense, moist, yellowish brown, orange brown, Silty, fine to medium SAND with little gravel -Medium dense, moist, orange brown. Silty, fine to medium SAND Stiff, moist, orange brown and gray, Sandy SILT -Stiff, moist, olive brown, Sandy SILT 32 15.8 15.9 - 34 BORING TERMINATED AT 11 FEET No groundwater encountered Figure A-6, Log of Boring B 6, Page 1 of 1 07349-42-11.GPJ D ..• SAMPLING UNSUCCESSFUL SAMPLE SYMBOLS ^ ... DISTURBED OR BAG SAMPLE B ... STANDARD PENETRATION TEST B ... CHUNK SAMPLE 1 ... DRIVE SAMPLE (UNDISTURBED) % ... WATER TABLE OR SEEPAGE NOTE THE LOG OF SUBSURFACE CONDmONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LCDCATION AND AT THE DATE INDICATED, rr IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDmONS AT OTHER LCXATIONS AND TIMES. GEOCON APPENDIX < APPENDIX B LABORATORY TESTING Laboratory tests were performed in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. Selected soil samples were tested for their in-place dry density and moisture content, maximum dry density and optimum moisture content, expansion potential, pH, resistivity, soluble sulfate content, and consolidation characteristics. The results of our laboratory tests are presented on Tables B-I througli B-IV and Figure B-1. TABLE B-1 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 wt.) B2-1 Olive Brown, fine Sandy CLAY 123.3 11.3 B3-1 Yellowi-sh-brown, fine to medium Sandy CLAY 125.1 11.0 TABLE B-il SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Sample No. Moisture Content Dry Density (pcO Expansion Index Classification Sample No. Before Test (%) After Test (%) Dry Density (pcO Expansion Index Classification B2-1 10.1 23.5 105.7 66 Medium B3-1 10.5 21.0 107.7 50 Low B4-1 11.7 23.4 105.5 60 Medium TABLE B-lll SUMMARY OF LABORATORY pH AND RESISTIVITY TEST RESULTS CALIFORNIA TEST NO. 643 Sample No. pH Minimum Resistivity (ohm-centimeters) B3-1 8.1 560 B5-1 8.2 510 Project No. 07349-42-11 - B-1 -October 6, 2010 TABLE B-IV SUMMARY OF LABORATORY SULFATE CONTENT RESULTS CALIFORNIA TEST NO. 417 Sample No. Sulfate (% S04) Sulfate Exposure B2-1 0.526 Severe B-1 0.442 Severe B4-1 0.683 Severe Project No. 07349-42-11 - B-2-October6, 2010 PROJECT NO. 07349-42-11 SAMPLE NO. 81-2 UJ U a- 0 .1 1 10 APPLIED PRESSURE (ksf) Initial Dry Density (pcf) 116.9 Initial Water Content (%) 13.1 no Initial Saturation (%) 83.2 Sample Saturated at (ksf) .5 CONSOUDATION CURVE CARLSBAD RACEWAY-LOT 17 CARLSBAD, CAUFORNIA 07349-42-11.GPJ Figure B-1 GEOCON APPENDIX APPENDIX C RECOMMENDED GRADING SPECIFICATIONS PREPARED FOR CARLSBAD RACEWAY BUSINESS PARK - LOT 17 CARLSBAD, CALIFORNIA PROJECT 07349-42-11 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL 1.1 These Recommended Grading Specifications shall be used in conjunction with the Geotechnical Report for the project prepared by Geocon Incorporated. The recommendations contained in the text of the Geotechnical Report are a part of the earthwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. 1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be employed for the purpose of observing earthwork procedures and testing the fills for substantial confonnance with the recommendations of the Geotechnical Report and these specifications. The Consultant should provide adequate testing and observation services so that they may assess whether, in their opinion, the work was performed in substantial conformance with these specifications. It shall be the responsibility of the Contractor to assist the Consultant and keep thein apprised of work schedules and changes so that personnel may be scheduled accordingly. 1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and methods to accomplish the work m accordance with applicable grading codes or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the Consultant, unsatisfactory conditions such as questionable soil materials, poor moismre condition, inadequate compaction, adverse weather, result in a quality of work not in conformance with these specifications, the Consultant will be empowered to reject the woric and recommend to the Owner that grading be stopped until the unacceptable conditions are corrected. 2. DEFINmONS 2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading work is being perfonned and who has contracted with the Contractor to have grading performed. 2.2 Contractor shall refer to the Contractor perfonning the site grading work. 2.3 Civil Engineer or Engineer of Work shall refer to the Califomia licensed Civil Engineer or consulting firm responsible for preparation of the grading plans, surveying and verifying as-graded topography. GI rev. 04/2009 2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. 2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner, who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be responsible for having qualified representatives on-site to observe and test the Contractor's work for confonnance with these specifications. 2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained by the Owner to provide geologic observations and recommendations during the site grading. 2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include a geologic reconnaissance or geologic investigation that was prepared specifically for the development of the project for which these Recommended Grading Specifications are intended to apply. 3. MATERIALS 3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or imported to the site that, in the opinion of the Consultant, is suitable for use in construction of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as defined below. 3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than 12 inches in maximum dimension and containing at least 40 percent by weight of material smaller than VA inch in size. 3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than 4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow for proper compaction of soil fill around the rock fragments or hard lumps as specified in Paragraph 6.2. Oversize rock is defined as material greater than 12 inches. 3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger dian 3 feet in maximum dimension and containing little or no fines. Fines are defined as material smaller than VA inch in maximum dimension. The quantity of fines shall be less than approximately 20 percent of the rock fill quantity. GI rev. 04/2009 3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the Consultant shall not be used in fills. 3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as defmed by the Califomia Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9 and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials are not hazardous as defined by applicable laws and regulations. 3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of properly compacted soil fill materials approved by the Consultant. Rock fill may extend to the slope face, provided that the slope is not steeper than 2:1 (horizontahvertical) and a soil layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This procedure may be utilized provided it is acceptable to the governing agency, Owner and Consultant. 3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the Consultant to determine the maximum density, optimum moisture content, and, where appropriate, shear strength, expansion, and gradation characteristics ofthe soil. 3.6 During grading, soil or groundwater conditions other than those identified in the Geotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the significance of the unanticipated condition 4. CLEARING AND PREPARING AREAS TO BE FILLED 4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of complete removal above the ground surface of trees, stumps, bmsh, vegetation, man-made stmctures, and similar debris. Grubbing shall consist of removal of smmps, roots, buried logs and other unsuitable material and shall be perfonned in areas to be graded. Roots and other projections exceeding 1 Vi inches in diameter shall be removed to a depth of 3 feet below the surface of the ground. Bonow areas shall be gmbbed to the extent necessary to provide suitable fill materials. GI rev. 04/2009 4.2 Any asphalt pavement material removed during clearing operations should be properly disposed at an approved off-site facility. Concrete fragments that are free of reinforcing steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this document. 4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or porous soils shall be removed to the depth recoinmended in the Geotechnical Report. The depth of removal and compaction should be observed and approved by a representative of the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth of 6 inches and until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. 4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or where recommended by the Consultant, the original ground should be benched in accordance with the following illustration. TYPICAL BENCHING DETAIL Finish Grade Original Ground Remove All Unsuitable Material As Recommended By Consultant Slope To Be Such That Sloughing Or Sliding Does Not Occur Finish Slope Surface See Note 2 _ No Scale DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. GI rev. 04/2009 4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture conditioned to achieve the proper moisture content, and compacted as recommended in Section 6 of these specifications. 5. COMPACTION EQUIPMENT 5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compaction equipment. Equipment shall be of such a design that it will be capable of compacting the soil or soil-rock fill to the specified relative compaction at the specified moisture content. 5.2 Compaction of rock fills shall be performed in accordance with Section 6.3. 6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL 6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with the following recommendations: 6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should generally not exceed 8 inches. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to obtain uniformity of material and moisture in each layer. The entire fill shall be constmcted as a unit in nearly level lifts. Rock materials greater than 12 inches in maximum dimension shall be placed in accordance with Section 6.2 or 6.3 of these specifications. 6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the optimum moisture content as determined by ASTM D 1557-02. 6.1.3 When the moisture content of soil fill is below that specified by the Consultant, water shall be added by the Contractor until the moisture content is in the range specified. 6.1.4 When the moisture content of the soil fill is above the range specified by the Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by the Contractor by blading/mixing, or other satisfactory methods until the moisture content is within the range specified. GI rev. 04/2009 6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the Contractor to a relative compaction of at least 90 percent. Relative compaction is defined as the ratio (expressed in percent) of the in-place dry density of the compacted fill to the maximum laboratory dry density as detemiined in accordance with ASTM D 1557-02. Compaction shall be continuous over the entire area, and compaction equipment shall make sufficient passes so that the specified minimum relative compaction has been achieved throughout the entire fill. 6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed at least 3 feet below finish pad grade and should be compacted at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. 6.1.7 Properly compacted .90// fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over-built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track-walking of slopes, as described in the following paragraph. 6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height intervals. Upon completion, slopes should then be track-walked with a D-8 dozxjr or similar equipment, such that a dozer track covers all slope surfaces at least twice. 6.2 Soil-rock fiW, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: 6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. 6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, rocks or rock fragments up to 10 feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading as specific cases arise and shall be approved by the Consultant prior to placement. Gl rev. 04/2009 6.2.3 For individual placement, sufficient space shall be provided between rocks to allow for passage of compaction equipment. 6.2.4 For windrow placement, die rocks should be placed in trenches excavated in properly compacted soil fill. Trenches should be approximately 5 feet wide and 4 feet deep in maximum dimension. The voids around and beneath rocks should be filled with approved granular soil having a Sand Equivalent of 30 or greater and should be compacted by flooding. Windrows may also be placed utilizing an "open-face" method in lieu of the trench procedure, however, this method should first be approved by the Consultant. 6.2.5 Windrows should generally be parallel to each other and may be placed either parallel to or perpendicular to the face of the slope depending on the site geometry. The minimum horizontal spacing for windrows shall be 12 feet center-to-center with a 5-foot stagger or offset from lower courses to next overlying course. The minimum vertical spacing between windrow courses shall be 2 feet from the top of a lower windrow to the bottom of the next higher windrow. 6.2.6 Rock placement, fill placement and flooding of approved granular soil in the windrows should be continuously observed by the Consultant. 6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with the following recommendations: 6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not develop. The subdrains shall be permanently connected to controlled drainage facilities to control post-constmction infiltration of water. 6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock tmcks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water tmcks traversing in front of the cunent rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20-ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the GI rev. 04/2009 required compaction or deflection as recommended in Paragraph 6.3.3 shall be utilized. The number of passes to be made should be determined as described in Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional rock fill lifts will be permitted over the soil fill. 6.3.3 Plate bearing tests, in accordance with ASTM D 1196-93, may be performed in both the compacted .TO/7 fill and in the rock fill to aid in detennining the required minimum number of passes of the compaction equipment. If performed, a minimum of three plate bearing tests should be perfonned in die properly compacted soil fill (minimum relative compaction of 90 percent). Plate bearing tests shall then be perfonned on areas of rock fill having two passes, four passes and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the results of the plate bearing tests for the soU fill and the rock fill and by evaluating the deflection variation with number of passes. The required number of passes of the compaction equipment will be perfonned as necessary until the plate bearing deflections are equal to or less than that determined for the properly compacted .TO/7 fill. In no case will the required number of passes be less than two. 6.3.4 A representative of the Consultant should be present during rock fill operations to observe that the minimum number of "passes" have been obtained, that water is being properly applied and that specified procedures are being followed. The actual number of plate bearing tests will be detennined by the Consultant during grading. 6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that, in their opinion, sufficient water is present and that voids between large rocks are properly filled with smaller rock material. In-place density testing will not be required in the rock fills. 6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying sod fill material, a 2-foot layer of graded filter material shall be placed above the uppermost lift of rock fill. The need to place graded filter material below the rock should be determined by the Consultant prior to commencing grading. The gradation of the graded filter material will be detennined at the time the rock fill is being excavated. Materials typical of the rock fill should be submitted to the Consultant in a timely manner, to allow design of the graded filter prior to the commencement of rock fill placement. 6.3.7 Rock fill placement should be continuously observed during placement by the Consultant. GI rev. 04/2009 7. OBSERVATION AND TESTING 7.1 The Consultant shall be the Owner's representative to observe and perforin tests during clearing, gmbbing, filling, and compaction operations. In general, no more than 2 feet in vertical elevation of sod or soil-rock fill should be placed without at least one field density test being performed within that interval. In addition, a minimum of one field density test should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and compacted. 7.2 The Consultant should perfonn a sufficient distribution of field density tests of the compacted sod or soil-rock fill to provide a basis for expressing an opinion whether the fill material is compacted as specified. Density tests shall be perfonned in the compacted materials below any disturbed surface. When these tests indicate that the density of any layer of fill or portion thereof is below that specified, the particular layer or areas represented by the test shall be reworked until the specified density has been achieved. 7.3 During placement of rock fill, the Consultant should observe that the minimum number of passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant should request the excavation of observation pits and may perform plate bearing tests on the placed rock fills. The observation pits will be excavated to provide a basis for expressing an opinion as to whether the rock fill is properly seated and sufficient moisture has been applied to the material. When observations indicate that a layer of rock fill or any portion thereof is below that specified, the affected layer or area shall be reworked until the rock fill has been adequately seated and sufficient moisture applied. 7.4 A settlement monitoring program designed by the Consultant may be conducted in areas of rock fill placement. The specific design of the monitoring program shall be as recommended in the Conclusions and Recommendations section of the project Geotechnical Report or in the final report of testing and observation services perfonned during grading. 7.5 The Consultant should observe the placement of subdrains, to verify that the drainage devices have been placed and constmcted in substantial conformance with project specifications. 7.6 Testing procedures shall con fomi to the following Standards as appropriate: GI rev. 04/2009 7.6.1 Soil and Soil-Rock Fills: 7.6.1.1 Field Density Test, ASTM D 1556-02, Density of Soil In-Place By the Sand-Cone Method. 7.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938-08A, Density of Sod and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth). 7.6.1.3 Laboratory Compaction Test, ASTM D 1557-02, Moisture-Density Relations of Sods and Soil-Aggregate Mixtures Using 10-Pound Hammer and 18-Inch Drop. 7.6.1.4. Expansion Index Test, ASTM D 4829-03, Expansion Index Test. 7.6.2 Rock Fills 7.6.2.1 Field Plate Bearing Test, ASTM D 1 196-93 (Reapproved 1997) Standard Method for Nonreparative Static Plate Load Tests of Soils and Flexible Pavement Components, For Use in Evaluation and Design of Airport and Highway Pavements. 8. PROTECTION OF WORK During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. Drainage of surface water shall be controlled to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas until such time as permanent drainage and erosion control features have been installed. Areas subjected to erosion or sedimentation shall be properly prepared in accordance with the Specifications prior to placing additional fill or stmctures. After completion of grading as observed and tested by the Consultant, no further excavation or filling shall be conducted except in conjunction with the services of the Consultant. GI rev. 04/2009 9. CERTIFICATIONS AND FINAL REPORTS 9.1 Upon completion of the work. Contractor shall furnish Owner a certification by the Civil Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot horizontally of the positions shown on the grading plans. After installation of a section of subdrain, the project Civil Engineer should survey its location and prepare an as-built plan of the subdrain location. The project Civil Engineer should verify the proper outlet for the subdrains and the Contractor should ensure that the drain system is free of obstmctions. 9.2 The Owner is responsible for furnishing a final as-graded soil and geologic report satisfactory to the appropriate governing or accepting agencies. The as-graded report should be prepared and signed by a Cahfomia licensed Civil Engineer experienced in geotechnical engineering and by a Califomia Certified Engineering Geologist, indicating that the geotechnical aspects of the grading were performed in substantial confonnance with the Specifications or approved changes to the Specifications. GI rev. 04/2009