GEOTECHNICAL INVESTIGATION UNITS B AND C QUARRY …...GEOTECHNICAL INVESTIGATION UNITS B AND C QUARRY FALLS (CIVITA) SAN DIEGO, CALIFORNIA PREPARED FOR QUARRY FALLS, LLC SAN DIEGO,

GEOTECHNICAL INVESTIGATION

UNITS B AND C QUARRY FALLS (CIVITA) SAN DIEGO, CALIFORNIA

PREPARED FOR

QUARRY FALLS, LLC SAN DIEGO, CALIFORNIA

APRIL 24, 2012 PROJECT NO. 06650-42-11

GROCON INCORPORATED

GEOTECHNICAL • ENVIRONMENTAL MATERIALSO

6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159

Project No. 06650-42-11 April 24, 2012 Quarry Falls, LLC 5465 Morehouse Drive, Suite 260 San Diego, California 92121 Attention: Mr. Marco Sessa Subject: GEOTECHNICAL INVESTIGATION UNITS B AND C QUARRY FALLS (CIVITA) SAN DIEGO, CALIFORNIA Dear Mr. Sessa: In accordance with your authorization, we have prepared this geotechnical investigation for the subject project. The site is underlain by compacted fill placed during reclamation grading overlying Stadium Conglomerate and Friars Formation. The accompanying report presents the results of our study and conclusions and recommendations regarding geotechnical aspects of site development. This report is based on our review of compaction reports prepared by others and field and laboratory testing recently performed by Geocon Incorporated. It is our opinion, based on the results of this study, that the site is suitable for development. The accompanying report presents conclusions and recommendations regarding geotechnical aspects of development. Should you have questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Rodney C. Mikesell GE 2533

Garry W. Cannon RCE 56468 CEG 2201

RCM:GWC:dmc (3) Addressee (1) Devcon CPM, LLC Attention: Mr. Matt Adams (3/del) Rick Engineering Company Attention: Mr. Troy Bales

TABLE OF CONTENTS

1. PURPOSE AND SCOPE ...................................................................................................................... 1

2. SITE DESCRIPTION AND PREVIOUS GRADING .......................................................................... 1

3. PROJECT DESCRIPTION ................................................................................................................... 2

4. SOIL AND GEOLOGIC CONDITIONS .............................................................................................. 3 4.1 Undocumented Fill (Qudf) ......................................................................................................... 3 4.2 Previously Placed Fill (Qpf) ....................................................................................................... 3 4.3 Stadium Conglomerate (Tst) ...................................................................................................... 4 4.4 Friars Formation (Tf) .................................................................................................................. 4

5. GROUNDWATER ............................................................................................................................... 4

6. GEOLOGIC HAZARDS ....................................................................................................................... 4 6.1 Faulting ....................................................................................................................................... 4 6.2 Seismicity-Deterministic Analysis ............................................................................................. 5 6.3 Seismicity-Probabilistic Analysis ............................................................................................... 6 6.4 Liquefaction ................................................................................................................................ 7 6.5 Geologic Hazard Category ......................................................................................................... 7

7. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 8 7.1 General ....................................................................................................................................... 8 7.2 Soil and Excavation Characteristics ........................................................................................... 8 7.3 Settlement Monitoring .............................................................................................................. 10 7.4 Subdrains .................................................................................................................................. 11 7.5 Grading Recommendations ...................................................................................................... 11 7.6 Slope Stability .......................................................................................................................... 12 7.7 Slopes ....................................................................................................................................... 12 7.8 Seismic Design Criteria ............................................................................................................ 13 7.9 Preliminary Foundation Recommendations ............................................................................. 14 7.10 Conventional Retaining Wall Recommendations..................................................................... 18 7.11 Preliminary Pavement Recommendations ................................................................................ 20 7.12 Bio-Retention Basin and Bio-Swale Recommendations .......................................................... 23 7.13 Site Drainage and Moisture Protection .................................................................................... 24 7.14 Grading and Foundation Plan Review ...................................................................................... 25

LIMITATIONS AND UNIFORMITY OF CONDITIONS

MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2, Geologic Map Figure 3, Geologic Cross Sections Figures 4 – 6, Slope Stability Analyses Figure 7, Wall/Column Footing Dimension Detail Figure 8, Typical Retaining Wall Drainage Detail

APPENDIX A FIELD INVESTIGATION Figures A-1 – A-5, Logs of Small Diameter Borings Figures A-6 – A-15, Logs of Large Diameter Borings APPENDIX B LABORATORY TESTING Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results Table B-II, Summary of Laboratory Expansion Index Test Results Table B-III, Summary of Laboratory Direct Shear Test Results Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results Table B-V, Summary of Laboratory Potential of Hydrogen (pH) and Resistivity Test Results Table B-VI, Summary of Laboratory One Dimensional Swell Tests Figure B-1, Gradation Curve Figures B-1 – B-10, Consolidation Curves APPENDIX C RECOMMENDED GRADING SPECIFICATIONS LIST OF REFERENCES

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GEOTECHNICAL INVESTIGATION

1. PURPOSE AND SCOPE

This report presents the results of our geotechnical investigation for Units B and C at Quarry Falls (Civita) located north of Friars Road and west of Interstate 805 in San Diego, California (see Vicinity Map, Figure 1). Units B and C are located in the southwest portion of the Civita Masterplan. The purpose of this report is to provide geotechnical recommendations for development of the project, and to evaluate surface and subsurface soil conditions, general site geology, and to identify geotechnical constraints, if any, that might impact development of the property.

The scope of this study consisted of a review of readily available published and unpublished geologic literature (see List of References), drilling 5 small-diameter borings and 10 large-diameter borings, soil sampling, laboratory testing, engineering analyses, and preparation of this report. Our scope also included a review of compaction reports prepared by Geomatrix and AMEC documenting the compaction of fills placed during reclamation grading. A detailed listing of the reports reviewed is presented in the List of References section at the end of this report.

Site geologic conditions are depicted on Figure 2 (Geologic Map). The geologic contacts were plotted on a base map provided by Rick Engineering Company. The plan depicts existing grades and proposed sheet grade elevations for this project. Geologic cross sections are provided on Figure 3. The base of compacted fill elevations are based on exploratory drilling where the bottom of fill was encountered and a plan titled Historic and Future Pit Floor, Mission Valley Plant, prepared by Vulcan Materials Company, dated February 7, 2008.

The conclusions and recommendations presented herein are based on our analysis of the data obtained from the exploratory field investigation, laboratory test results, review of compaction reports associated with reclamation grading which has occurred on the property, and our experience with similar soil and geologic conditions on this and adjacent properties.

2. SITE DESCRIPTION AND PREVIOUS GRADING

The project site covered under this study is located in the southwest portion of the overall Quarry Falls (Civita) property that comprises approximately 215 acres of land situated north of Friars Road between Mission Center Road and Interstate 805. Vulcan Materials Company previously used the property to mine and produce sand and aggregate products. Mining occurred over several decades. Recently, active mining has ceased; however, a concrete batch plant is in operation in the southeastern portion of the overall Quarry Falls (Civita). A new batch plant is currently being constructed on a graded parcel at the southeast corner of the property. The new batch plant will

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replace the current batch plant, enabling the completion of reclamation grading in the southeastern portion of the overall property.

Mining has resulted in removal of rock and soil deposits resulting in deep excavations, as well as relatively steep cut slopes on the northern and eastern perimeters of the overall property. The majority of the deep excavations were backfilled with waste materials generated during mining activities. This resulted in relatively thick undocumented fill deposits with abrupt near-vertical formational sidewall contacts.

In 2003, reclamation grading commenced with removal of undocumented fill from portions of the property. Placement of compacted fill started in April 2004 under the testing and observation of Geomatrix Consultants, Inc. Grading has continued through 2012 resulting in undocumented fill being removed and replaced as compacted fill. In June 2008, AMEC Earth & Environmental acquired Geomatrix. Following this merger, AMEC Geomatrix, Inc. performed observation of undocumented fill removals and compaction testing. A summary of compaction test results was provided in Geomatrix, Inc. and AMEC Geomatrix, Inc.’s reports (see List of References). Geomatrix and AMEC Geomatrix reported compaction testing was performed approximately every 1 to 2 vertical feet and that the fill was placed and compacted to at least 90 percent relative compaction.

Within the southwester portion of the Grant Property, to which this report pertains, fill depths are estimated to range from less than 5 feet near the southeast corner to approximately 30 feet in the northern and western portions of the property (based on exploratory borings and review of the pit floor map). Based on our review of AMEC Geomatrix, Inc.’s reports, the majority of fill within Units B and C was been placed in 2011. Some fills along the western edge were placed in 2008 and 2009. Sewer mains were installed in Units B and C as part of the off-site work for Civita Phase A.

The site area covered by this report slopes from north to south with surface elevations ranging from approximately 110 feet Mean Sea Level (MSL) at the northwest corner to near 55 feet MSL along the southern property margin. Drainage ditches have been constructed along the west side, east side and through the central portion of the site for storm water runoff control. The ditches convey storm water runoff to detention basins. A detention basin within the Civita Phase A grading area exists near the southwest corner of the property. The existing basin will be reconfigured during completion of grading for Civita Phase A and is not a part of Units B and C, to which this report pertains.

3. PROJECT DESCRIPTION

We understand future development plans include regarding the site to construct relatively large sheet graded building pads for support of high density residential, mixed-use, public and private open

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space areas. Based on preliminary plans, regrading will result in cuts and fills on the order of 15 feet and 10 feet, respectively from reclamation grades. As part of the grading, the existing drainage ditches will be infilled. Temporary detention basins will be constructed on each sheet graded pad.

The locations and descriptions provided herein are based on a review of available information including previous geotechnical reports prepared for the property and grading plans prepared by Rick Engineering. If project details change significantly from those described herein, Geocon Incorporated should be contacted to evaluate potential impacts with respect to the site soil and geologic conditions and to determine if the proposed changes will require revision of this report.

4. SOIL AND GEOLOGIC CONDITIONS

The site is underlain by compacted fill placed during reclamation grading. The fill is underlain by Stadium Conglomerate and Friars Formation. Undocumented fill associated with drainage ditch berms are also present on the property. The soil and geologic units are described below. Their approximate lateral extent is shown on the Geologic Map (Figure 2).

4.1 Undocumented Fill (Qudf)

Nonstructural berms and stockpile fills associated with drainage ditch excavations and excavation spoils exist on the site. Near the terminus of Via Alta at the northwest corner of the property, spoils from the adjacent Circa 37 project have been placed and stockpiled. Along the western side of the site, stockpile soils from the drainage ditch excavation exist. Undocumented fill is unsuitable for support of structural improvements, and will require removal and recompaction.

4.2 Previously Placed Fill (Qpf)

The site is underlain by compacted fill placed during reclamation grading that began in late 2003 and is ongoing. Reclamation grading for areas B and C was recently completed in 2011. Geomatrix Consultants, Inc. and AMEC Geomatrix, Inc. observed and tested the placement of compacted fill. Based on information contained in Geomatrix’s reports, the fill has a relative compaction of at least 90 percent. The fill is generally composed of silty to clayey sand with some gravel and cobble. The source of the fill was soil generated during the mining and aggregate production activities. Maximum fill thickness as observed in the borings is 32 feet. Based on maps showing pit bottom elevations, the maximum depth of fill is estimated to be between 30 and 40 feet. Based on observation of the fill by downhole logging of large diameter borings during our field investigation, the fill appears to be relatively uniform, have good moisture content, and is considered suitable for support of planned structural improvements.

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4.3 Stadium Conglomerate (Tst)

The Eocene-age Stadium Conglomerate is the predominant formational unit on the site and underlies the compacted fill. This unit was the primary material mined to generate aggregate. In general, the Stadium Conglomerate consists of a dense to very dense, yellow to light brown, cobble conglomerate. The deposit contains a relatively high percentage of rounded cobble (up to approximately 60 percent by weight) embedded in a silty to clayey, fine to medium sand soil matrix. The cobble typically ranges in size from approximately 3 inches to 12 inches. The Stadium Conglomerate underlies portions of the previously placed fill where it was not excavated during mining activities. When excavated, the Stadium Conglomerate typically consists of low to very low expansive silty/clayey sands that possess good shear strength characteristics in either a natural or properly compacted condition. The Stadium Conglomerate is suitable for support of additional fill and structural loading.

4.4 Friars Formation (Tf)

The Friars Formation is expected to underlie the Stadium Conglomerate. In some areas where the Stadium Conglomerate was completely mined, the Friars Formation is present at the bottom of the mine pit. Typically, the Friars Formation is composed of hard sandy claystone and siltstone, and dense, fine- to coarse-grained silty to clayey sandstone. The Friars Formation is not expected to be encountered during grading or utility construction for this project. The Friars Formation is suitable for support of additional fill and structural loading.

5. GROUNDWATER

Groundwater is expected to be relatively deep and not expected to adversely impact the project. Groundwater was not encountered in exploratory borings performed for this field investigation. However, it is not uncommon for groundwater or seepage conditions to develop where none previously existed. Groundwater elevations are dependent on seasonal precipitation, irrigation, land use, among other factors, and vary as a result. Proper surface drainage will be important to future performance of the project.

6. GEOLOGIC HAZARDS

6.1 Faulting

Our review of geologic literature indicates that there are no known active or potentially active faults at the site. The Florida Canyon and Texas Street Faults are located approximately 4,400 feet and 2,400 feet to the south of the site, respectively. These faults are considered to be inactive or potentially inactive. The trend of these faults does not project across the property. The Rose Canyon/Newport-Inglewood Fault Zone, located approximately 3 miles west of the site, is the closest

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known active fault. The California Geological Survey (CGS) defines an active fault as a fault showing evidence for activity roughly within the last 11,000 years. The CGS has included portions of the Rose Canyon Fault within an Alquist-Priolo Earthquake Fault Zone. This subject site is not located within such a zone.

Faulting was observed on the eastern mined slope for the overall Grant Property adjacent to Interstate 805. A report specific to this fault was prepared by Geocon Incorporated and is titled Limited Geologic Fault Investigation, Quarry Falls, San Diego, California, dated December 23, 2010. Based on our review of available information, it is our opinion no active or potentially active faults cross the property.

6.2 Seismicity-Deterministic Analysis

In order to determine the distance of known faults to the site, the computer program EZ-FRISK (Version 7.62) was utilized. In addition to fault location, EZ-FRISK was used to estimate ground accelerations at the site for the maximum anticipated seismic event.

According to the results of the EZ-FRISK analysis, 5 known active faults are located within a search radius of 50 miles from the property. The nearest known active fault is the Rose Canyon/Newport-Inglewood Fault Zone, located approximately 3 miles west of the site and is the dominant source for potential ground motion. The estimated maximum earthquake magnitude and peak ground acceleration for the Rose Canyon/Newport-Inglewood Fault Zone is 7.5 and 0.46 g, respectively.

Table 6.2 lists the estimated maximum earthquake magnitudes and peak ground accelerations (PGA) for the most dominant faults for the site location calculated for Site Class D as defined by Table 1613A.5.3 of the 2010 CBC. Boore-Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2008) NGA acceleration-attenuation relationships were used in the calculation of the PGAs.

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TABLE 6.2 DETERMINISTIC SPECTRA SITE PARAMETERS

Fault Name Distance from Site

(miles)

Maximum Earthquake Magnitude

(Mw)

Peak Ground Acceleration

Boore-Atkinson 2008 (g)

Campbell-Bozorgnia 2008 (g)

Chiou-Youngs 2008 (g)

Newport-Inglewood/Rose Canyon 3 7.5 0.38 0.36 0.46

Coronado Bank 41 7.4 0.21 0.16 0.19

Palos Verdes Connected 41 7.7 0.23 0.17 0.22

Elsinore 38 7.85 0.15 0.10 0.12

Earthquake Valley 43 6.8 0.09 0.06 0.05

6.3 Seismicity-Probabilistic Analysis

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 slip rate. The program accounts for fault rupture length as a function of earthquake magnitude. 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) rupture length for a given magnitude, (3) location of the rupture 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 USGS2008, Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2008) in the analysis. Table 6.3.1 presents the site-specific probabilistic seismic hazard parameters including acceleration-attenuation relationships and the probability of exceedence.

TABLE 6.3.1 PROBABILISTIC SEISMIC HAZARD PARAMETERS

Probability of Exceedence Peak Ground Acceleration

Boore-Atkinson, 2008 (g)

Campbell-Bozorgnia, 2008 (g)

Chiou-Youngs, 2008 (g)

2% in a 50 Year Period 0.51 0.46 0.53

5% in a 50 Year Period 0.36 0.32 0.36

10% in a 50 Year Period 0.26 0.23 0.25

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The California Geologic Survey (CGS) provides a computer program that calculates the ground motion for a 10 percent of probability of exceedence in 50 years based on the average value of several attenuation relationships. Table 6.3.2 presents the calculated results from the Probabilistic Seismic Hazards Mapping Ground Motion Page from the CGS website.

TABLE 6.3.2 PROBABILISTIC SITE PARAMETERS FOR SELECTED FAULTS

CALIFORNIA GEOLOGIC SURVEY

Calculated Acceleration (g) Firm Rock

Calculated Acceleration (g) Soft Rock

Calculated Acceleration (g) Alluvium

0.26 0.28 0.32

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 frequency and duration of motion and soil conditions underlying the site. Seismic design of the structures should be evaluated in accordance with the California Building Code (CBC) guidelines.

6.4 Liquefaction

Soil liquefaction occurs within relatively loose, cohesionless sand located below the water table that is subjected to ground accelerations from earthquakes. Due to the dense nature of the underlying soils and the lack of permanent, shallow groundwater, there is a very low risk for liquefaction occurring at the site.

6.5 Geologic Hazard Category

Review of the 2008 City of San Diego Seismic Safety Study, Geologic Hazards and Faults, indicates the site is mapped as Geologic Hazard Category 53. Category 53 is level or sloping terrain, unfavorable geologic structure, low to moderate risk. The site is not located on any known active or potentially active fault trace. The site consists of large, sheet-graded, gently sloping, building pads underlain by compacted fill or Stadium Conglomerate.

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7. CONCLUSIONS AND RECOMMENDATIONS

7.1 General

7.1.1 No soil or geologic conditions were observed that would preclude the development of the property as presently proposed provided that the recommendations of this report are followed.

7.1.2 The site is underlain by previously placed fill overlying the Stadium Conglomerate and Friars Formation. The previously placed fill thickness is expected to vary from less than 5 feet near the southeast corner to approximately 30 feet in the northern, central and western portions of the property. The previously placed fill is suitable for support of structural improvements based on exploratory borings, laboratory testing, and our review of available compaction reports. The Stadium Conglomerate and Friars Formation are also suitable for support of structural fill and loads.

7.1.3 Areas of undocumented fill were observed on the property. Undocumented fill is expected to have relatively minor thickness and will need to be removed and recompacted.

7.1.4 Previously placed fill observed and tested by Geomatrix, Inc. and AMEC Geomatrix, Inc. was observed to have relatively good moisture content and density. Consolidation curves indicate the fill has a low potential for loading induced compression. Based on our observation of the fill within the geotechnical borings and the results of the laboratory testing, the compacted fill appears to be suitable in its present condition for support of new fill and/or structural loading.

7.1.5 Based on our experience and laboratory testing, we expect the majority of on-site soils to possess a low to medium expansion potential. We also expect the soils to have a negligible sulfate exposure to concrete structures.

7.1.6 Based on our experience with on-site soils, we expect the soils to be corrosive to buried metal. The corrosive nature of the soils should be considered in the design of buried metal pipes and underground structures.

7.2 Soil and Excavation Characteristics

7.2.1 The soil encountered in the field investigation is considered to be expansive (expansion index [EI] of greater than 20) as defined by 2010 California Building Code (CBC) Section 1802.3.2. Table 7.2.1 presents soil classifications based on the expansion index. Based on our experience with waste product from the Vulcan Materials Plant, the

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expansion index for the majority of the fill soils should be less than 90. The expansion index on a sample of topsoil from the northern parcel indicated a high expansion potential.

TABLE 7.2.1 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

7.2.2 We performed laboratory tests on samples of the site soils to check the percentage of water-soluble sulfate content. Results from the laboratory water-soluble sulfate content tests, presented in Appendix B, indicate the on-site materials at the locations tested possess negligible sulfate exposure to concrete structures as defined by 2010 CBC Section 1904.3 and ACI 318. Table 7.2.2 presents a summary of concrete requirements set forth by 2010 CBC Section 1904.3 and ACI 318 Sections 4.2 and 4.3. Based on the water-soluble sulfate test results, Type I or II cement is appropriate. 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 7.2.2 REQUIREMENTS FOR CONCRETE EXPOSED TO

SULFATE-CONTAINING SOLUTIONS

Sulfate Exposure

Exposure Class

Water-Soluble Sulfate % by

Weight

Cement Type

Maximum Water to

Cement Ratio by Weight

Minimum Compressive

Strength (psi)

Negligible S0 0.00-0.10 I or II -- 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

7.2.3 We performed laboratory pH and resistivity tests on samples soil to check whether the soils are corrosive with respect to buried metal. Table B-V of Appendix B summarizes the

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test results. The results indicate the soils sampled are corrosive with respect to buried metals. The corrosive nature of the soils should be considered in the design of buried metal pipes and underground structures.

7.2.4 Geocon Incorporated does not practice in the field of corrosion engineering; therefore, further evaluation by a corrosion engineer may be needed to incorporate the necessary precautions to avoid premature corrosion of underground pipes and buried metal in direct contact with soil.

7.2.5 The existing on-site compacted fills can be excavated with a light to moderate effort with conventional grading equipment. Trenching for installation of the underground utilities should also require a normal effort with typical underground excavation equipment. Where formational Stadium Conglomerate is encountered, difficult excavation requiring a very heavy effort should be anticipated.

7.2.6 Estimates of embankment bulking and shrinkage factors are based on comparing laboratory compaction tests with the density of the material in its natural or compacted state, as encountered in the exploratory borings. It should be emphasized that the variations in natural soil density, as well as compacted fill densities, render shrinkage value estimates very approximate. As an example, the contractor can compact the fill soils to any relative compaction greater than 90 percent of the maximum laboratory density. Thus, the contractor has approximately a 10 percent range of control over the fill volume. Based on the findings of this study and experience with similar soil conditions, the following shrinkage/bulking factors can be used as a basis for estimating how much the on-site soils may shrink or bulk when excavated from their present condition and placed as compacted fill. We expect the previously placed compacted fill to have very little bulking or shrinkage.

TABLE 7.2.3 ESTIMATED BULKING AND SHRINKING FACTORS

Soil Unit Shrink/Bulk Factor

Previously Placed Compacted Fill 2 percent shrink to 2 percent bulk

Stadium Conglomerate Formation 3 to 6 percent bulk

7.3 Settlement Monitoring

7.3.1 Based on our review of AMEC Geomatrix, Inc.’s reports, the majority of fill within Unit B and C was placed between 2008 and 2011. Based on the results of settlement monitoring performed for the adjacent Civita project, and considering the maximum fill depth is

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approximately 30 to 40 feet, we expect the majority of settlement as a result of self-weight compression has occurred. Settlement monitoring is not recommended.

7.3.2 Grading on the site will result in cuts and fills of less than 15 feet from reclamation sheet grades. We do not expect the planned new fill will cause significant settlement of the underlying compacted fill. In our opinion, settlement monitoring is not required after regarding that will occur as part of this project.

7.4 Subdrains

7.4.1 Subdrains are not required for the project due to the shallow nature of proposed new fills associated with constructing the sheet-graded lots.

7.5 Grading Recommendations

7.5.1 All grading should be performed in accordance with the Recommended Grading Specifications contained in Appendix C. Where the recommendations of this section conflict with those of Appendix C, the recommendations of this section take precedence. All earthwork should be observed and all fill tested for proper compaction by Geocon Incorporated.

7.5.2 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 and fill areas, or soils to be used as fill are relatively free of organic matter. Material generated during stripping should be exported from the site.

7.5.3 Undocumented fill should be completely removed to expose dense compacted fill prior to placing additional fill or structural loads. Within the existing drainage ditch areas accumulated soft and saturated soils should be removed to expose competent previous compacted fill prior to placing compacted fill.

7.5.4 Prior to placing fill, the base of excavations and surface of previously placed fill should be scarified; moisture conditioned as necessary and compacted. Fill soils may then be placed and compacted in layers to the design finish grade elevations. In general, on-site soils are suitable for re-use as fill if free from vegetation, debris and other deleterious material. Layers of fill should be no thicker than will allow for adequate bonding and compaction. All fill, including scarified ground surfaces and backfill, should be compacted to at least 90 of laboratory maximum dry density as determined by ASTM Test Procedure D-1557 at

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or slightly above optimum moisture content. Overly wet materials will require drying and/or mixing with drier soils to facilitate proper compaction.

7.5.5 The upper 3 feet of fill on all lots and streets should be composed of properly compacted very low to medium expansive soils. Highly expansive soils, if encountered, should be placed in deeper fill areas and properly compacted. Very low to medium expansive soils are defined as those soils that have an Expansion Index of 90 or less. Cobbles, concretions, concrete chunks greater than 12 inches in maximum dimension should not be placed within 5 feet of finish grade or 3 feet from the deepest utility within streets.

7.5.6 Import fill (if necessary) should consist of granular materials with a very low to low expansion potential (EI of 50 or less), be free of deleterious material or stones larger than 3 inches, and should be compacted as recommended herein. Geocon Incorporated should be notified of the import soil source and should be authorized to perform laboratory testing of import soil prior to its arrival at the site to evaluate its suitability as fill material.

7.6 Slope Stability

7.6.1 Slope stability analyses were performed for proposed new 2:1 fill slopes for maximum proposed slope heights (30 feet or less) shown on the grading plan. The deep-seated analysis was performed using the computer program Geoslope 2007. The surficial analysis was performed using simplified Janbu analysis. Our analyses utilized average drained direct shear strength parameters based on laboratory tests performed for this project. The analyses indicates new slopes excavated in and constructed with on-site materials have calculated factors of safety in excess of 1.5 under static conditions for both deep-seated failure and shallow sloughing conditions. A summary of slope stability analyses is presented on Figures 4 and 5.

7.6.2 We also performed a stability analysis for proposed basin slopes under the maximum water height and under rapid drawdown conditions. The results of our analyses indicate the basin slopes are stable with a factor of safety in excess of 1.5. Figure 6 graphically depicts the stability analyses. It is also our opinion that temporary basins as shown on the grading plan should not impact adjacent slopes.

7.7 Slopes

7.7.1 It is recommended that all slope excavations be observed during grading by an engineering geologist to verify that soil and geologic conditions do not differ significantly from those anticipated.

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7.7.2 The outer 15 feet (or a distance equal to the height of the slope, whichever is less) of fill slopes should be composed of properly compacted granular soil fill to reduce the potential for surficial sloughing. All slopes should be compacted by backrolling with a loaded sheepsfoot roller at vertical intervals not to exceed 4 feet and should be track-walked at the completion of each slope such that the fill soils are uniformly compacted to at least 90 percent relative compaction to the face of the finished sloped.

7.7.3 From a geotechnical engineering standpoint slope terracing is not required to provide stable slope conditions. The project civil engineer may need to be contacted to evaluate if terracing or benches are required for drainage purposes.

7.7.4 All slopes should be landscaped with drought-tolerant vegetation, having variable root depths and requiring minimal landscape irrigation. In addition, all slopes should be drained and properly maintained to reduce erosion.

7.8 Seismic Design Criteria

7.8.1 The site is characterized as Site Class D based on the thickness of compacted fill beneath the site. We used the computer program Seismic Hazard Curves and Uniform Hazard Response Spectra, provided by the United States Geologic Survey (USGS), to evaluate design parameters. Table 7.8 summarizes site-specific design criteria obtained from the 2010 CBC, Chapter 16 Structural Design, Section 1613 Earthquake Loads (based on the 2009 International Building Code [IBC]).

TABLE 7.8 2010 CBC SEISMIC DESIGN PARAMETERS

Parameter Value 2010 CBC Reference

Site Class D Table 1613.5.2

Spectral Response – Class B (0.2 sec), SS 1.453 g Figure 1613.5(3)

Spectral Response – Class B (1 sec), S1 0.541 g Figure 1613.5(4)

Site Coefficient, Fa 1.0 Table 1613.5.3(1)

Site Coefficient, Fv 1.5 Table 1613.5.3(2)

Maximum Considered Earthquake Spectral Response Acceleration (0.2 sec), SMS

1.453 g Section 1613.5.3 (Eqn 16-36)

Maximum Considered Earthquake Spectral Response Acceleration – (1 sec), SM1

0.811 g Section 1613.5.3 (Eqn 16-37)

5% Damped Design Spectral Response Acceleration (0.2 sec), SDS

0.969 g Section 1613.5.4 (Eqn 16-38)

5% Damped Design Spectral Response Acceleration (1 sec), SD1

0.541 g Section 1613.5.4 (Eqn 16-39)

Project No. 06650-42-11 - 14 - April 24, 2012

7.8.2 Conformance to the criteria in Table 7.8 for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if a maximum level earthquake occurs. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive.

7.9 Preliminary Foundation Recommendations

7.9.1 Determination of final foundation design for a particular type of building and lot can be provided after site regrading is complete and when specific structure design plans are available. However, for preliminary planning purposes, general foundation design guidelines for one- to four-story structures are presented below.

7.9.2 The following foundation recommendations apply to one- to four-story structures and are based on the building pads being underlain by properly compacted fill and soil within 3 feet of finish grade consisting of very low to medium expansive soils (Expansion Index of 90 or less).

7.9.3 Continuous footings should be founded at least 24 inches below lowest adjacent grade and should be at least 12 inches wide. Reinforcement should consist of four, No. 5 steel, reinforcing bars, two placed near the top of the footing and two near the bottom. Isolated spread footings should be a minimum of 2.5 feet square and founded at least 24 inches below lowest adjacent grade. The project structural engineer should design reinforcement for spread footings. A typical footing detail is provided on Figure 7.

7.9.4 Footings proportioned as recommended above may be designed for an allowable soil bearing pressure of 2,000 psf (dead plus live loads). The soil bearing pressure may be increased by 300 psf and 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil bearing pressure of 4,000 psf. The allowable bearing pressure may be increased by up to one-third when considering transient loading such as those due to wind or seismic forces.

7.9.5 We expect primary settlement of existing fills is essentially complete. However, we estimate that additional settlement as a result of hydro-consolidation to be approximately 0.2 to 0.3 percent of the fill thickness. We estimate a maximum total settlement of approximately 0.8 to 1.25 inches (based on 35 feet of fill). We estimate a differential fill settlement of less than 1 inch across sheet graded pads. Differential fill thickness and settlement magnitudes to be used in foundation design should be provided in update reports once building locations on individual pads are known. Foundations will need to be designed to accommodate estimated total and differential fill settlement.

Project No. 06650-42-11 - 15 - April 24, 2012

7.9.6 Conventional building concrete slabs-on-grade should be at least 5 inches thick and reinforced with No. 3 bars spaced 18 inches on center in both directions placed at the slab midpoint. The concrete slab-on-grade recommendations are based on soil support characteristics only. The project structural engineer should evaluate the structural requirements of the concrete slabs for supporting planned loading. Thicker concrete slabs may be required for heavier loads.

7.9.7 A vapor retarder should underlie slabs that may receive moisture-sensitive floor coverings or may be used to store moisture-sensitive materials. The vapor retarder design should be consistent with the guidelines presented in the American Concrete Institute’s (ACI) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06). In addition, the membrane should be installed in accordance with manufacturer’s recommendations and ASTM requirements and installed in a manner that prevents puncture. The project architect or developer should specify the type of vapor retarder used based on the type of floor covering that will be installed and if the structure will possess a humidity controlled environment.

7.9.8 The project foundation engineer, architect, and/or developer should determine the thickness of bedding sand below the slab. However, Geocon should be contacted to provide recommendations if the bedding sand is thicker than 6 inches.

7.9.9 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. We suggest that the foundation design engineer present the concrete mix design and proper curing methods on the foundation plans. It is critical that the foundation contractor understands and follows the specifications presented on the foundation plans.

7.9.10 As an alternative to the conventional foundations, consideration should be given to the use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The post-tensioned systems should be designed by a structural engineer experienced in post-tensioned slab design and design criteria of the Post-Tensioning Institute (PTI), Third Edition, as required by the 2007 California Building Code (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 on Table 7.9. The parameters presented in Table 7.9 are based on the guidelines presented in the PTI, Third Edition design manual.

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TABLE 7.9 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS

Post-Tensioning Institute (PTI) Third Edition Design Parameters Design Parameter

Thornthwaite Index -20

Equilibrium Suction 3.9

Edge Lift Moisture Variation Distance, eM (feet) 4.9

Edge Lift, yM (inches) 1.58

Center Lift Moisture Variation Distance, eM (feet) 9.0

Center Lift, yM (inches) 0.66

7.9.11 The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. For moisture cut-off, we recommend the perimeter foundation have an embedment depth of at least 12 inches. If a post-tensioned mat foundation system is planned, the slab should possess a thickened edge with a minimum width of 12 inches that extends at least 12 inches below the clean sand layer.

7.9.12 If the structural engineer proposes a post-tensioned foundation design method other than PTI, Third Edition:

• The deflection criteria presented in Table 7.9 are still applicable. • Interior stiffener beams should be used. • The width of the perimeter foundations should be at least 12 inches. • The perimeter footing embedment depths should be at least 24 inches. The

embedment depths should be measured from the lowest adjacent pad grade.

7.9.13 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.

7.9.14 During the construction of the post-tension foundation system, the footing and slab concrete should be placed monolithically. Under no circumstances should cold joints form

Project No. 06650-42-11 - 17 - April 24, 2012

between the footings/grade beams and the slab during the construction of the post-tension foundation system.

7.9.15 Isolated footings, if present, should have the minimum embedment depth and width recommended for conventional foundations. 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. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams.

7.9.16 Due to the depth of the fills, consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to reduce the potential for future separation to occur.

7.9.17 Exterior slabs not subject to vehicle loads should be at least 4 inches thick and reinforced with 6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh. The mesh should be placed within the upper one-third of the slab. Proper mesh positioning is critical to future performance of the slabs. The contractor should take extra measures to provide proper mesh placement. Prior to construction of slabs, the subgrade should be moisture conditioned to at least optimum moisture content and compacted to a dry density of at least 90 percent of the laboratory maximum dry density.

7.9.18 Special subgrade presaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary, to maintain a moist condition as would be expected in any such concrete placement.

7.9.19 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, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope.

• When located next to a descending 3:1 (horizontal:vertical) fill slope or steeper, the foundations should be extended to a depth where the minimum horizontal distance is equal to H/3 (where H equals the vertical distance from the top of the fill slope to the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The horizontal distance is measured from the outer, deepest edge of the

Project No. 06650-42-11 - 18 - April 24, 2012

footing to the face of the slope. An acceptable alternative to deepening the footings would be the use of a post-tensioned slab and foundation system or increased footing and slab reinforcement. Specific design parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined.

• If 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, which are relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures that would permit some lateral soil movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations.

7.9.20 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: limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur.

7.9.21 Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer.

7.10 Conventional Retaining Wall Recommendations

7.10.1 Retaining walls that are allowed to rotate more than 0.001H (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 pcf. Where the backfill will be inclined at 2:1 (horizontal:vertical), an active

Project No. 06650-42-11 - 19 - April 24, 2012

soil pressure of 50 pcf is recommended. Expansive soils should not be used as backfill material behind retaining walls. All soil placed for retaining wall backfill should have an Expansion Index less than 50.

7.10.2 Soil contemplated for use as retaining wall backfill, including import materials, should be identified in the field prior to backfill. At that time Geocon Incorporated should obtain samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures may be necessary if the backfill soil does not meet the required expansion index or shear strength. City or regional standard wall designs, if used, are based on a specific active lateral earth pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may or may not meet the values for standard wall designs. Geocon Incorporated should be consulted to assess the suitability of the on-site soil for use as wall backfill if standard wall designs will be used.

7.10.3 Where walls are restrained from movement at the top, an additional uniform pressure of 7H psf 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 2 feet of fill soil should be added (unit weight 130 pcf).

7.10.4 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 of less than 50) free-draining backfill material with no hydrostatic forces or imposed surcharge load. Figure 8 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.

7.10.5 The structural engineer should determine the seismic design category for the project and if retaining walls need to incorporate seismic lateral loads. A seismic load of 20H 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 base of the wall and zero at top of the wall. We used a peak site acceleration of 0.39g calculated from the 2007 California Building Code (SDS/2.5) and applying a pseudo-static coefficient of 0.33.

Project No. 06650-42-11 - 20 - April 24, 2012

7.10.6 In general, wall foundations 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 3 feet below the base of the wall consists of compacted fill with an Expansion Index of less than 90. 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 anticipated.

7.10.7 To resist lateral loads, a passive pressure equivalent to the pressure exerted by a fluid density of 300 pcf should be used for design of footings or shear keys poured neat against properly compacted granular fill soils. The upper 12 inches of material in areas not protected by floor slabs or pavement should not be included in design for passive resistance.

7.10.8 If friction is to be used to resist lateral loads, an allowable coefficient of friction between soil and concrete of 0.35 should be used for design.

7.10.9 The recommendations presented above are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet are planned, Geocon Incorporated should be consulted for additional recommendations.

7.11 Preliminary Pavement Recommendations

7.11.1 Preliminary pavement recommendations for the streets and parking lots are provided below. The final pavement sections should be based on the R-Value of the subgrade soil encountered at final subgrade elevation. Based on our experience of soils in the area, we have assumed an R-Value of 15 for the subgrade soil. Preliminary flexible pavement sections are presented in Table 7.11.1. The City of San Diego will require the pavement sections to meet City of San Diego Schedule J in public streets or private streets with public utilities. Pavement sections are provided below for varying traffic indices for both standard pavement design using Class 2 Aggregate base and the design section using City of San Diego Schedule “J”, which requires cement treated base (CTB). The project civil engineer or traffic engineer should determine the appropriate Traffic Index (TI) or traffic loading expected on the project for the various pavement areas that will be constructed.

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TABLE 7.11.1 ASPHALT CONCRETE PAVEMENT SECTIONS

Traffic Index

Pavement Design Section Pavement Design Section Schedule “J”

Asphalt Concrete (inches)

Class 2 Base (inches)

Asphalt Concrete (inches)

Cement Treated Base (inches)

5 3 8 3 7 5.5 3 10 3 8 6 3 9.5 3 9

6.5 3 11.5 3 10.5 7 3 15 3 12

7.5 3.5 15.5 3.5 12.5 8 3.5 17.5 3.5 14

8.5 4 18 4 14.5

7.11.2 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public Works Construction (Green Book). Cement treated base should conform to Greenbook Section 301-3.3. Class 2 aggregate base materials should conform to Section 26-1.02A of the Standard Specifications of the State of California, Department of Transportation (Caltrans).

7.11.3 Prior to placing base material, the subgrade should be scarified, moisture conditioned and recompacted to a minimum of 95 percent relative compaction. The depth of compaction should be at least 12 inches. The base material should be compacted to at least 95 percent relative compaction. Asphalt concrete should be compacted to a density of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726.

7.11.4 A rigid Portland Cement concrete (PCC) pavement section should be placed in driveway entrance aprons, trash bin loading/storage areas and loading dock areas. The concrete pad for trash truck areas should be large enough such that the truck wheels will be positioned on the concrete during loading. We calculated the rigid pavement section in general conformance with the procedure recommended by the American Concrete Institute report ACI 330R-01 Guide for Design and Construction of Concrete Parking Lots using the parameters presented in Table 7.11.2.

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TABLE 7.11.2 RIGID PAVEMENT DESIGN PARAMETERS

Design Parameter Design Value

Modulus of subgrade reaction, k 100 pci

Modulus of rupture for concrete, MR 500 psi

Traffic Category, TC A-1 and C

Average daily truck traffic, ADTT 1 and 100

7.11.5 Based on the criteria presented herein, the PCC pavement sections should have a minimum thickness as presented in Table 7.11.3.

TABLE 7.11.3 RIGID PAVEMENT RECOMMENDATIONS

Location Portland Cement Concrete (inches)

Automobile Areas (TC=A-1, ADDT = 1) 5

Heavy Truck and Fire Lane Areas (TC=C, ADDT = 100) 7

7.11.6 The PCC pavement should be placed over subgrade soil that is compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. This pavement section is based on a minimum concrete compressive strength of approximately 3,200 psi (pounds per square inch).

7.11.7 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 or a minimum thickness of 2 inches, whichever results in a thicker edge, at the slab edge and taper back to the recommended slab thickness 3 feet behind the face of the slab (e.g., a 7-inch-thick slab would have a 9-inch-thick edge). Reinforcing steel will not be necessary within the concrete for geotechnical purposes with the exception of loading docks, trash bin enclosures, and dowels at construction joints as discussed below.

7.11.8 Loading aprons, such as those used for trash bin enclosures and loading docks, should be constructed using Portland cement concrete as recommended above for heavy truck traffic areas. The pavement should be reinforced with a minimum of No. 3 steel reinforcing bars spaced 24 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 both the front and rear wheels of the truck will be located on reinforced concrete pavement when loading.

Project No. 06650-42-11 - 23 - April 24, 2012

7.11.9 To control the location and spread of concrete shrinkage cracks, crack-control joints (weakened plane joints) should be included in the design of the concrete pavement slab. Crack-control joints should not exceed 30 times the slab thickness with a maximum spacing of 15 feet (e.g., a 7-inch-thick slab would have a 15-foot spacing pattern) and should be sealed with an appropriate sealant to prevent the migration of water through the control joint to the subgrade materials. The depth of the crack-control joints should be determined by the referenced ACI report.

7.11.10 To provide load transfer between adjacent pavement slab sections, a trapezoidal-keyed construction joint should be installed. As an alternative to the keyed joint, dowelling is recommended between construction joints. As discussed in the referenced ACI guide, dowels should consist of smooth, ⅞-inch-diameter reinforcing steel 14 inches long embedded a minimum of 6 inches into the slab on either side of the construction joint. Dowels should be located at the midpoint of the slab, spaced at 12 inches on center and lubricated to allow joint movement while still transferring loads. The project structural engineer may provide alternative recommendations for load transfer.

7.11.11 The performance of pavement is highly dependent on providing positive surface drainage away from the edge of the pavement. Ponding of water on or adjacent to the pavement will likely result in pavement distress and subgrade failure. Drainage from landscaped areas should be directed to controlled drainage structures. Landscape areas adjacent to the edge of asphalt pavements are not recommended due to the potential for surface or irrigation water to infiltrate the underlying permeable aggregate base and cause distress. Where such a condition cannot be avoided, consideration should be given to incorporating measures that will significantly reduce the potential for subsurface water migration into the aggregate base. If planter islands are planned, the perimeter curb should extend at least 6 inches below the level of the base materials.

7.12 Bio-Retention Basin and Bio-Swale Recommendations

7.12.1 The site is underlain by compacted fill that is generally composed of silty to clayey sand. The compacted fill generally has a fine content (minus 200) of 25 to 50 percent. Based on our experience with the on-site soils, the compacted fill has low permeability and generally low infiltration characteristics. It is our opinion the compacted fill is unsuitable for infiltration of storm-water runoff.

7.12.2 Any bio-retention 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

Project No. 06650-42-11 - 24 - April 24, 2012

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 concrete cut-off wall should extend at least 6-inches beyond the perimeter of the gravel-packed subdrain system.

7.12.3 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 (i.e., compacted fills), permanent bio-retention basins 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.

7.12.4 We understand a bioretention swale is planned through the central portion of the site. The bioswale detail provided by the project civil engineer indicates a subdrian will be installed at the bottom of the bioswale and the edges of the bioswale will slope toward the drain. Provided no structural surface improvements are planned within 20 feet of the bioswale and the drain has positive flow to a discharge outlet, it is our opinion a liner is not required considering the low permeability of the on-site compacted fills. We do not expect the bioswales near the toe of the slopes will cause slope instability. Where the bioswale crosses underground utilities, we recommend an impermeable liner be placed at the base of the bioswale to a horizontal distance of 15 feet on each side of the utility line.

7.12.5 The landscape architect should be consulted to provide the appropriate plant recommendations. If drought resistant plants are not used, irrigation may be required.

7.13 Site Drainage and Moisture Protection

7.13.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed away from structures in accordance with 2010 CBC 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.

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7.13.2 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.

7.13.3 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.

7.14 Grading and Foundation Plan Review

7.14.1 Geocon Incorporated should review the grading plans and foundation plans for the project prior to final design submittal to evaluate whether additional analyses and/or recommendations are required.

Project No. 06650-42-11 April 24, 2012

LIMITATIONS 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 construction, or if the proposed construction will differ from that anticipated herein, Geocon Incorporated should be notified so that supplemental recommendations can be given. The evaluation or identification of the potential presence of hazardous or corrosive 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 performed the geotechnical investigation for the project should be retained to provide testing and observation services during construction to provide continuity of geotechnical interpretation and to check that the recommendations presented for geotechnical aspects of site development are incorporated during site grading, construction of improvements, and excavation of foundations. If another geotechnical firm is selected to perform the testing and observation services during construction operations, that firm should prepare a letter indicating their intent to assume the responsibilities of project geotechnical engineer of record. A copy of the letter should be provided to the regulatory agency for their records. In addition, that firm should provide revised recommendations concerning the geotechnical aspects of the proposed development, or a written acknowledgement of their concurrence with the recommendations presented in our report. They should also perform additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record.

APPENDIX A

Project No. 06650-42-11 April 24, 2012

APPENDIX A

FIELD INVESTIGATION

Fieldwork for our investigation included subsurface exploration and soil sampling. The approximate locations of the exploratory borings are shown on the geologic map Figure 2. We located the borings in the field based on existing site reference points. Therefore, actual boring locations may deviate slightly. Only those borings performed within Units B and C are shown on Figure 2.

We performed the field investigation on March 12 through March 16, 2012. The exploration consisted of drilling 5 small-diameter borings and 10 large-diameter exploratory borings. The borings were drilled to depths ranging from 6.5 feet to 102 feet below existing ground surface using a CME 75 with 8-inch hollow-stem augers for the small-diameter borings and an EZ Bore bucket auger drill rig equipped with a 30-inch diameter bucket for the large-diameter borings. The trenches were excavated using a John Deere 410 rubber-tire backhoe equipped with a 2-foot wide bucket. We obtained bulk and ring samples from the exploratory borings and trenches for laboratory testing.

We obtained relatively undisturbed soil samples from the borings using a California Modified split-spoon sampler. The sampler has an inside diameter of 2.5 inches and an outside diameter of 2.875 inches. Up to 18 rings that are 2.4 inches in diameter and 1.0 inch in height are placed inside the sampler. Soil samples were collected by driving the sampler 12 to 18 inches into the bottom of the excavation using a 140 pound hammer on the small-diameter drill rig and with the weight of the drill rig Kelly bar (1,300 to 3,500 pounds) on the large-diameter drill rig. The number of blows required to drive the sampler 12 inches was recorded. The penetration resistances shown on the boring logs are shown in terms of blows per foot. These values are not to be taken as N-values. Ring samples were retained in moisture-tight containers and transported to our laboratory for testing. Bulk samples were also collected from the borings for laboratory testing. The type of sample is noted on the exploratory boring and trench logs.

We visually examined, classified and logged the soil conditions encountered in the borings in general accordance with American Society for Testing and Materials (ASTM) practice for Description and Identification of Soils (Visual-Manual Procedure D 2488). Logs of the exploratory borings are presented on Figures A-1 through A-15. Although only the locations of borings performed for Unit B and C are shown on Figure 2, we have included all of the boring logs for Units B, C and F herein to provide a compressive summary of all of the field and laboratory testing performed for the previously placed fill. The logs depict the soil and geologic conditions encountered and the depth at which samples were obtained. Elevations shown on the logs were based on existing elevations shown on topographic maps provided for our use.

PREVIOUSLY COMPACTED FILLMedium dense, moist, olive brown, Clayey, fine to medium SAND, with littlegravel

-Mottled, olive brown and grayish brown at 5 feet

-Difficult drilling at 13 feet

-Driller change to alternate cutting head; unable to drill trough cobble

BORING TERMINATED AT 14.5 FEETRefusal due to cobble

Groundwater not encounteredBackfilled with soil cuttings

SCSB1-1

SB1-2

SB1-3

SB1-4

24

40

50/5"

06650-42-11 (UNITS B AND C).GPJ

MATERIAL DESCRIPTION

LIT

HO

LOG

Y

... STANDARD PENETRATION TEST

SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)

Figure A1,Log of Boring SB 1, Page 1 of 1

03-12-2012

SAMPLE SYMBOLS... WATER TABLE OR SEEPAGE

DEPTH

IN

FEET

... DRIVE SAMPLE (UNDISTURBED)

CME 75 w/8" HSA PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED

... SAMPLING UNSUCCESSFUL

DR

Y D

EN

SIT

Y

EQUIPMENT

BORING SB 1

ELEV. (MSL.) 208'

MO

IST

UR

E

BY:

... DISTURBED OR BAG SAMPLE

GEOCON

NOTE:

PROJECT NO.

THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. ITIS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.

06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense, moist, mottled olive and yellowish brown, Clayey, fine tomedium SAND with little gravel and cobble

-Olive brown to brown, few to little gravel at 5 feet

-Sampled on cobble at 10 feet

-Mottled olive brown and yellowish brown at 15 feet

-Trace concrete chunk in shoe cuttings at 20 feet

-Difficult drilling at 23 feet due to cobble

-Same at 25 feet

SC

SB2-1

SB2-2

SB2-3

SB2-4

SB2-5

SB2-6

14.5

10.4

15.2

54

27

61/11"

42

44

29

117.7

120.5

110.9



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-12-2012


DEPTH

IN

FEET


CME 75 w/8" HSA PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING SB 2

ELEV. (MSL.) 213'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

Becomes medium dense, Clayey SAND to stiff, Sandy CLAY; with somecobble in shoe at 30 feet


Becomes dense, mottled grayish brown and yellowish brown, Clayey SANDwith some cobble; sampled on cobble at 35 feet-Refusal at 36½ feet; unable to drill through cobble



CL-SC

SC

SB2-7

SB2-8

37

77/11½"



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-12-2012


DEPTH

IN

FEET


CME 75 w/8" HSA PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING SB 2

ELEV. (MSL.) 213'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense, moist, yellowish brown, Clayey, fine to medium SAND withlittle gravel and cobble-Difficult drilling between 3-5 feet due to cobble

STADIUM CONGLOMERATEVery dense, damp, olive brown, Cobbly CONGLOMERATE; with fine tomedium sandy matrix, cobble up to 4" diameter



SC

GP

SB3-1

SB3-2

68

50/4"



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-12-2012


DEPTH

IN

FEET


CME 75 w/8" HSA PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING SB 3

ELEV. (MSL.) 57'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense, moist, mottled olive brown and brown, Clayey, fine tomedium SAND with little gravel

-Becomes cobbly


BORING TERMINATED AT 8 FEETRefusal to cobble


SC

SB4-1

SB4-2

14.2

13.7

33

27

120.0

116.6



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-12-2012


DEPTH

IN

FEET


CME 75 w/8" HSA PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING SB 4

ELEV. (MSL.) 64'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense, moist, mottled olive brown and brown, Clayey, fine tomedium SAND with some gravel_Difficult drilling at 1.5 feet due to cobble-Difficult drilling due to cobble

BORING TERMINATED AT 2 FEETRefusal due to cobble


SC



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-12-2012


DEPTH

IN

FEET


CME 75 w/8" HSA PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING SB 5

ELEV. (MSL.) 71'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense, moist, yellowish gray, Silty, fine to medium SAND with tracegravel, occasional cobble

-A piece of root approximately 1" thick-Becomes dense, moist, yellowish brown, Silty SAND with little gravel

-Chunks of greenish gray sandy clay at 8 feet

-Cobble 10" diameter

-Cobble 10" diameter, north side of the hole

-Medium dense to dense, moist, yellowish brown, fine to medium SiltySAND, with clay, some gravel and occasional cobble, uniform

-Boulder at 21 feet

-Boulder at 25 feet

SM

LB1-1

LB1-2

LB1-3

LB1-4

3

3

3



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)

Figure A6,Log of Boring LB 1, Page 1 of 4

03-13-2012


DEPTH

IN

FEET


EZ BORE w/30" BUCKET PE

NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 1

ELEV. (MSL.) 210'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

-Becomes very dense, moist, less gravelly

-Becomes dense, moist, light yellowish gray, Silty, fine SAND, trace gravel

-Becomes cobbly with boulders - using auger to drill from 41 to 47 feet,boulder to 18" diameter

Becomes dense, moist, grayish brown, Silty, Clayey, fine to medium SANDwith little gravel

-Becomes more gravelly

SM

SM/SC

LB1-5

LB1-6

LB1-7

10.3

19.9

13.6

8

5

6

118.2

104.7

116.7



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-13-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

38

40

42

44

46

48

50

52

54

56

58

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 1

ELEV. (MSL.) 210'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

Dense, moist, yellowish brown, Silty, fine to medium SAND with little gravel

-A layer of dense, moist, yellowish gray, medium to coarse SAND with finegravel (1 foot thick)

Dense, moist, yellowish brown, Silty to Clayey, fine to medium SAND withlittle gravel

Dense, moist, grayish brown, Silty SAND with little gravel

SM

SM/SC

SM

LB1-8

LB1-9

LB1-10

LB1-11

19.2

11.6

12

12

15

20

103.4

118.8



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-13-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

60

62

64

66

68

70

72

74

76

78

80

82

84

86

88

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 1

ELEV. (MSL.) 210'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

Dense, moist, yellowish brown, Silty, fine to medium SAND with some graveland cobble

Dense to very dense, moist, yellowish brown, Silty, fine to medium SANDwith little gravel

BORING TERMINATED AT102 FEETMaximum reach of the drill rig

Backfilled with soil cuttingsSome compation effort made with bucket

SM

LB1-12 13.420 116.1



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-13-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

90

92

94

96

98

100

102

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 1

ELEV. (MSL.) 210'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIUOSLY COMPACTED FILLMedium dense to dense, moist, yellowish brown, Silty/Clayey, fine SANDwith some gravel and little cobble

Becomes dense, moist, yellowish brown, Silty, fine to medium SAND withsome gravel

-Boulders up to 12" diameter from 21 to 23 feet

-(used auger to get through boulder)

SM/SC

SM

LB2-1

LB2-2

LB2-3

LB2-4

14.8

9.5

1

1

5

117.1

113.9



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-14-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 2

ELEV. (MSL.) 181'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

Dense to very dense, moist, dark yellowish brown, Silty, fine to mediumSAND with little gravel

-Dense, moist, light yellowish brown, Silty, fine to medium SAND, tracegravel

-Becomes very dense, yellowish gray

Dense, moist, yellowish brown, Clayey, fine to medium SAND with littlegravel

Medium dense, moist, yellowish brown, Silty/Clayey, fine to medium SANDwith little cobble from 56 to 58 feet

-Becomes very dense, moist, with fine gravel, occasional cobbles

SM

SC

SM/SC

LB2-5

LB2-6

LB2-7

11.5

15.0

12.9

8

3

5

121.5

111.2

121.0



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-14-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

38

40

42

44

46

48

50

52

54

56

58

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 2

ELEV. (MSL.) 181'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

- (COBBLE IN SAMPLER)

-Large boulders

-Used auger to go through boulders

Very dense, moist, yellowish brown, Silty, fine to medium SAND with tracegravel

BORING TERMINATED AT 71 FEETNo groundwater encounteredBackfilled with soil cuttings

Some compation effort made with bucket

SM/SC

SM

LB2-8

LB2-9 11.3

12/8"

12 125.5



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-14-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

60

62

64

66

68

70

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 2

ELEV. (MSL.) 181'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACED FILLMedium dense to dense, moist, yellowish brown, Silty, fine to medium SANDwith some gravel and occasional cobbles

-Dense, moist, grayish to yellowish brown, Silty, fine SAND with little graveland small chunks of dark gray and brown sandy clay

Dense, moist, dark gray, Clayey, fine to medium SAND

Dense, moist, grayish brown, Silty, fine to medium SAND with some graveland cobbles

-Becomes medium dense, gravelly from 25 to 27 feet

SM

SC

SM

LB3-1

LB3-2

LB3-3

LB3-4

10.0

16.4

16.3

2

2

3

113.5

113.0

109.6



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-14-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 3

ELEV. (MSL.) 162'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

Dense, moist, grayish brown, Silty, fine to medium SAND with little graveland small chunks of dark gray, clayey sand

-Becomes dense, moist, yellowish brown, Silty, fine SAND with trace gravel

-A layer of Silty, medium to coarse SAND with gravel from 42 to 43 feet

-Small chunks of asphalt at 47 feet and 49 feet

Dense, moist, yellowish brown, Silty/Clayey, fine to medium SAND with littlegravel

SM

SM/SC

LB3-5

LB3-6

LB3-7

11.7

17.0

13.7

5

4

4

115.3

106.4

114.6



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-14-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

38

40

42

44

46

48

50

52

54

56

58

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 3

ELEV. (MSL.) 162'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

-Becomes more gravelly with cobbles

Very dense, moist, yellowish brown, Silty, fine to medium SAND with littlegravel

BORING TERMINATED AT 66 FEETNo groundwater encounteredBackfilled with soil cuttings

Some compation effort made with bucket

SM

LB3-8

LB3-9

12.212

10

118.7



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-14-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

60

62

64

66

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 3

ELEV. (MSL.) 162'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense to dense, moist, mottled olive brown and yellowish brown,Clayey, fine to medium SAND, with little gravel and few cobbles up to 10"diameter

-Few to little cobble up to 8" diameter

-Auger used due to 18" diameter boulder at 8 feet

-Medium dense at 15 feet

-Medium dense to dense at 17 feet

-Asphalt chunk at 22 feet

-Trace rootlets and trace organic odor at 25 feet and 27½ feet

STADIUM CONGLOMERATEDense, damp, mottled orange brown and yellowish brown, fine to mediumSANDSTONE with trace silt

SC

SP

LB4-1

LB4-2

LB4-3

2

3

2



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 4

ELEV. (MSL.) 91'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

Very dense, Cobbly CONGLOMERATE with some cobbles up to 10"diameter

BORING TERMINATED AT 32 FEETGroundwater not encounteredBackfilled with soil cuttings

Some compaction effort made with bucket

SP

GP



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 4

ELEV. (MSL.) 91'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense to dense, mottled olive brown and yellowish brown, Clayey,fine to medium SAND with little gravel and few cobbles up to 8" diameter

Stiff to very stiff, moist, mottled olive brown and yellowish brown, SandyCLAY with little gravel and few cobble up to 4" diameter

Medium dense to dense, moist, mottled olive brown to yellowish brown,Clayey, fine to medium SAND with little gravel and few cobble up to 6"diameter

-Approximately 18" diameter boulder at 9 feet

-Small piece of rubber at 17 feet

-Trace rootlet at 19 feet

-Trace asphalt chunks at 27 feet

SC

CL

SC

LB5-1

LB5-2

LB5-3

LB5-4

17.63

1

3

110.0



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 5

ELEV. (MSL.) 79'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

-Sampled on coble at 30 feet

STADIUM CONGLOMERATEDense to very dense, mottled grayish brown and orange brown, CobblyCONGLOMERATE with some boulders up to 18" diameter and race clay

-Difficult drilling between 31 to 36 feet



SC

GM

LB5-5 10



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 5

ELEV. (MSL.) 79'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense to dense, moist, mottle olive brown and yellowish brown,Clayey, fine to medium SAND with little gravel and few cobble up to 8"diameter

-Trace rootlets at 5 feet

-Trace asphalt chunks between 10 feet and 13 feet

-Piece of PVC pipe at 12 feet

-Trace steel wire, approximately ¼" thick wood, and asphalt between 16½ feetand 17½ feet

-A piece of concrete, rootlets and trace asphalt between 23 feet and 25 feet

STADIUM CONGLOMERATEDense to very dense, moist, mottled orange brown and yellowish brown,

SCLB6-1

LB6-2

LB6-3

LB6-4

LB6-5

17.7

11.0

2

6/8"

3

4

111.4

112.9



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 6

ELEV. (MSL.) 66'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

matrix, Cobbly CONGLOMERATE with some cobbles up to 10" diameter-Difficult drilling between 28 feet and 31 feet

BORING TERMINATED AT 31.5 FEETGroundwater not encounteredBackfilled with soil cuttings


GP



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 6

ELEV. (MSL.) 66'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense to dense, moist, mottle olive brown and yellowish brown,Clayey, fine to medium SAND with gravel and trace cobble up to 10"diameter

-Trace rootlets at 10½ feet

STADIUM CONGLOMERATEDense to very dense, moist, mottled orange brown and yellowish brown,Gravelly CONGLOMERATE with fine to medium sand matrix, few cobblesup to 12" diameter



SC

GP

LB7-1

LB7-2

2

6/8"



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 7

ELEV. (MSL.) 60'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense to dense, moist, mottled olive brown and yellowish brown,Clayey, fine to medium SAND with little gravel and few cobble up to 6"diameter

STADIUM CONGLOMERATEDense to very dense, damp, mottled orange brown and yellowish brown, fineto medium Cobbly CONGLOMERATE with cobbles up to 10" diameter

BORING TERMINATED AT 3.5 FEETGroundwater not encounteredBackfilled with soil cuttings


SC

GP



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

A. SADR

SAMPLE

NO.

CO

NT

EN

T (

%)


03-15-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 8

ELEV. (MSL.) 57'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dense to dense, moist, mottled olive brown and yellowish brown,Clayey, fine to medium SAND with little gravel and few cobble up to 6"diameter

-Trace asphalt, a piece of concrete and approximately 1/4" diameter rootletsbetween 12 to 13 feet

-Few to little cobble up to 6" diameter between 25 to 27 feet

SC

LB9-1

LB9-2

LB9-3

LB9-4

LB9-5

LB9-6

1

3

2

3

3



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-16-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 9

ELEV. (MSL.) 74'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

-Mottled reddish brown and olive brown between with trace rootlets between33 feet to 38 feet

-Sampled on boulder at 40 feet

-Concrete chunk at 45'

OLD ALLUVIUMMedium dense to stiff, moist, olive brown, Clayey, fine to medium SAND toSandy CLAY with interbedded yellowish brown lenses of medium to coarsesand; little gravel and cobble up to 8" diameter

-Becomes wet at 52 feet

-Seepage at 54 feet; soil saturated

BORING TERMINATED AT 55 FEETSeepage at 54 feet

Backfilled with soil cuttingsSome compaction effort made with bucket

SC

SC/CL

LB9-7

LB9-8

LB9-9

LB9-12

LB9-10

LB9-11

6

4

5

5



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-16-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

38

40

42

44

46

48

50

52

54

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 9

ELEV. (MSL.) 74'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

PREVIOUSLY COMPACTED FILLMedium dende to dense, moist, mottled olive brown and yellowish brown,Clayey, fine SAND with little gravel and few cobble up to 8" diameter

-Becomes dense, little cobble up to 8" diameter at 5 feet

-Sampled on cobble at 10 feet

-Becomes very dense

-Piece of cloth at 28 feet

SC

LB10-1

LB10-2

LB10-3

3

4/8"

3



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-16-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 10

ELEV. (MSL.) 102'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

-Trace concrete chunks at 33 feet

Very dense, moist, olive brown to yellowish brown, Clayey, fine SANDwithgravel and coble

FRIARS FORMATIONDense to very dense, dmp to moist, grayish brown, orange, Silty, fine tomedium SANDSTONE with trace clay

BORING TERMIATED AT 46.5 FEET

SC

SM



LIT

HO

LOG

Y


SOIL

CLASS

(USCS)

GR

OU

ND

WA

TE

R

E. ALVARADO

SAMPLE

NO.

CO

NT

EN

T (

%)


03-16-2012


DEPTH

IN

FEET



NE

TR

AT

ION

RE

SIS

TA

NC

E(B

LOW

S/F

T.)

30

32

34

36

38

40

42

44

46

... CHUNK SAMPLE

(P.C

.F.)

DATE COMPLETED


DR

Y D

EN

SIT

Y

EQUIPMENT

BORING LB 10

ELEV. (MSL.) 102'

MO

IST

UR

E

BY:


GEOCON

NOTE:

PROJECT NO.


06650-42-11

APPENDIX B

Project No. 06650-42-11 - B-1 - April 24, 2010

APPENDIX B

We performed laboratory tests in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. We tested selected samples for their in-place dry density and moisture content, maximum dry density and optimum moisture content, expansion index, shear strength, water-soluble sulfate characteristics, pH and resistivity, swell potential, gradation and consolidation characteristics. The results of our laboratory tests are presented in Tables B-I through B-VI, and Figures B-1 through B-10. The in-place dry density and moisture content test results are presented on the exploratory boring logs in Appendix A.

TABLE B-I 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.)

LB5-1 Olive brown, Clayey, fine SAND with some gravel 128.5 10.2

T3-2 Brown, fine to medium Sandy SILT with little clay and trace gravel 110.5 17.5

TABLE B-II SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS

ASTM D 4829

Sample No. Moisture Content (%) Dry Density

(pcf) Expansion

Index Expansion

Classification Before Test After Test

SB1-1 11.0 20.6 109.4 35 Low

LB2-1 10.3 22.4 108.8 48 Low

LB5-1 10.1 21.2 110.0 51 Medium

T2-1 12.1 29.1 103.8 102 High

T3-2 12.3 27.4 98.4 43 Low

Project No. 06650-42-11 - B-2 - April 24, 2010

TABLE B-III SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS

ASTM D 3080

Sample No. Dry Density (pcf)

Moisture Content (%) Unit Cohesion

(psf)

Angle of Shear Resistance-

Ultimate (degrees)

Initial Final

*LB5-1 115.0 10.8 19.7 324 23 LB6-2 111.4 17.7 23.8 710 26 *T3-2 99.7 18.9 26.4 50 31

*Sample remolded to approximately 90 percent relative compaction near optimum moisture content.

TABLE B-IV SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS

CALIFORNIA TEST NO. 417

Sample No. Water-Soluble Sulfate (%) Classification

SB1-1 0.024 Negligible

LB2-1 0.025 Negligible

T3-2 0.028 Negligible

TABLE B-V SUMMARY OF LABORATORY POTENTIAL OF HYDROGEN (pH) AND RESISTIVITY TEST RESULTS

CALIFORNIA TEST NO. 417

Sample No. pH Resistivity (ohm-cm)

SB1-1 8.4 480 LB5-1 8.7 430

TABLE B-VI SUMMARY OF LABORATORY ONE-DIMENSIONAL SWELL TESTS

ASTM D 4546 – METHOD B

Sample No. Depth of Sample (feet)

Dry Density (pcf)

Moisture Content (%)

Load – Water Added (ksf) Percent Swell

SB4-1 2.5 120.0 14.2 0.5 1.3

0

10

20

30

40

50

60

70

80

90

100

0.0010.010.1110

3/8" 4

PROJECT NO. 06650-42-11

U. S. STANDARD SIEVE SIZE

COARSE

3" 3/4"1-1/2"8 16

2030

40

PL

FINE

NAT WC

PE

RC

EN

T F

INE

R B

Y W

EIG

HT

(SC) Clayey SAND0.0

PI

COARSE

GRAVEL


SB1-1

QUARRY FALLS (CIVITA)SAN DIEGO, CALIFORNIA

SAND

MEDIUM

5060 100 200

SAMPLE

GEOCON

SILT OR CLAYFINE

GRAIN SIZE IN MILLIMETERS

CLASSIFICATION LL

10

DEPTH (ft)

UNITS B AND C

Figure B-1

GRADATION CURVE

-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100

Sample Saturated at (ksf)

GEOCON


Initial Dry Density (pcf)

PROJECT NO. 06650-42-11

Initial Water Content (%)

Initial Saturation (%) 94

1.0

PE

RC

EN

T C

ON

SO

LID

AT

ION

14.8

SAMPLE NO. LB2-3

SAN DIEGO, CALIFORNIA

CONSOLIDATION CURVE

117.1

APPLIED PRESSURE (ksf)

Figure B-2

UNITS B AND CQUARRY FALLS (CIVITA)

-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



4.0

PE

RC

EN

T C

ON

SO

LID

AT

ION

15.0

SAMPLE NO. LB2-6


CONSOLIDATION CURVE

111.2


Figure B-3


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



0.5

PE

RC

EN

T C

ON

SO

LID

AT

ION

10.0

SAMPLE NO. LB3-1


CONSOLIDATION CURVE

113.5


Figure B-4


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



1.0

PE

RC

EN

T C

ON

SO

LID

AT

ION

16.3

SAMPLE NO. LB3-4


CONSOLIDATION CURVE

109.6


Figure B-5


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



4.0

PE

RC

EN

T C

ON

SO

LID

AT

ION

11.7

SAMPLE NO. LB3-5


CONSOLIDATION CURVE

115.3


Figure B-6


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



1.0

PE

RC

EN

T C

ON

SO

LID

AT

ION

17.6

SAMPLE NO. LB5-2


CONSOLIDATION CURVE

110.0


Figure B-7


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



1.0

PE

RC

EN

T C

ON

SO

LID

AT

ION

11.0

SAMPLE NO. LB6-4


CONSOLIDATION CURVE

112.9


Figure B-8


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



0.5

PE

RC

EN

T C

ON

SO

LID

AT

ION

14.5

SAMPLE NO. SB2-2


CONSOLIDATION CURVE

117.7


Figure B-9


-4

-2

0

2

4

6

8

10

12

14

160.1 1 10 100


GEOCON



PROJECT NO. 06650-42-11



0.5

PE

RC

EN

T C

ON

SO

LID

AT

ION

13.7

SAMPLE NO. SB4-2


CONSOLIDATION CURVE

116.6


Figure B-10


APPENDIX C

APPENDIX C

RECOMMENDED GRADING SPECIFICATIONS

FOR

UNITS B AND C QUARRY FALLS (CIVITA) SAN DIEGO, CALIFORNIA

PROJECT NO. 06650-42-11

GI rev. 04/2009

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 conformance 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 them 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 in 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 moisture

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

work and recommend to the Owner that grading be stopped until the unacceptable

conditions are corrected.

2. DEFINITIONS

2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading

work is being performed and who has contracted with the Contractor to have grading

performed.

2.2 Contractor shall refer to the Contractor performing the site grading work.

2.3 Civil Engineer or Engineer of Work shall refer to the California 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 conformance 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 ¾ 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 than 3 feet

in maximum dimension and containing little or no fines. Fines are defined as

material smaller than ¾ 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

defined by the California 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 (horizontal:vertical) 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 of the 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, brush, vegetation, man-made

structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried

logs and other unsuitable material and shall be performed in areas to be graded. Roots and

other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet

below the surface of the ground. Borrow areas shall be grubbed 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 recommended 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

Remove AllUnsuitable MaterialAs Recommended ByConsultant

Finish Grade Original Ground

Finish Slope Surface

Slope To Be Such ThatSloughing Or SlidingDoes Not Occur Varies

“B”

See Note 1

No Scale

See Note 2

1

2

DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permitcomplete coverage with the compaction equipment used. The base of the key shouldbe graded horizontal, or inclined slightly into the natural slope.

(2) The outside of the key should be below the topsoil or unsuitable surficial materialand at least 2 feet into dense formational material. Where hard rock is exposed in thebottom of the key, the depth and configuration of the key may be modified asapproved 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 constructed 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

determined 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 soil 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 dozer

or similar equipment, such that a dozer track covers all slope surfaces at least

twice.

6.2 Soil-rock fill, 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.

GI 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, the 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-construction infiltration of water.

6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock

trucks 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 trucks traversing in front of the current 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 soil fill and in the rock fill to aid in determining the required

minimum number of passes of the compaction equipment. If performed, a

minimum of three plate bearing tests should be performed in the properly

compacted soil fill (minimum relative compaction of 90 percent). Plate bearing

tests shall then be performed 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 soil 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 performed as necessary until the plate bearing deflections are

equal to or less than that determined for the properly compacted soil 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 determined 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 soil

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 determined 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 perform tests during

clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in

vertical elevation of soil 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 perform a sufficient distribution of field density tests of the

compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill

material is compacted as specified. Density tests shall be performed 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 performed

during grading.

7.5 The Consultant should observe the placement of subdrains, to verify that the drainage

devices have been placed and constructed in substantial conformance with project

specifications.

7.6 Testing procedures shall conform 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 theSand-Cone Method.

7.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938-08A, Density of Soiland Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).

7.6.1.3 Laboratory Compaction Test, ASTM D 1557-02, Moisture-DensityRelations of Soils and Soil-Aggregate Mixtures Using 10-PoundHammer 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 1196-93 (Reapproved 1997)Standard Method for Nonreparative Static Plate Load Tests of Soils andFlexible Pavement Components, For Use in Evaluation and Design ofAirport and Highway Pavements.

8. PROTECTION OF WORK

8.1 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 structures.

8.2 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 obstructions.

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 California licensed Civil Engineer experienced in

geotechnical engineering and by a California Certified Engineering Geologist, indicating

that the geotechnical aspects of the grading were performed in substantial conformance

with the Specifications or approved changes to the Specifications.

Project No. 06650-42-11 April 24, 2012

LIST OF REFERENCES

1. Boore, D. M. and G. M Atkinson (2006), Boore-Atkinson NGA Ground Motion Relations for the Geometric Mean Horizontal Component of Peak and Spectral Ground Motion Parameters, Report Number PEER 2007/01, May 2007.

2. Brain S. J. Chiou and Robert R. Youngs, A NGA Model for the Average Horizontal Component of Peak Ground Motion and Response Spectra, preprint for article to be published in NGA Special Edition for Earthquake Spectra, Spring 2008.

3. California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic Hazard Assessment for the State of California, Open File Report 96-08, 1996.

4. California Geological Survey, Seismic Shaking Hazards in California, Based on the USGS/ CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April 2003). 10% probability of being exceeded in 50 years. http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html

5. Campbell, K. W., Y. Bozorgnia, NGA Ground Motion Model for the Geometric Mean Horizontal Component of PGA, PGV, PGD and 5% Damped Linear Elastic Response Spectra for Periods Ranging from 0.01 to 10 s, Preprint of version submitted for publication in the NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February 2008.

6. Characterization of San Diego’s Stadium Conglomerate For Tunnel Design, 2001 Proceedings Rapid Excavation and Tunneling Conference, pgs. 33-45.

7. Geomatrix, Progress Report 1, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated April 12, 2005.

8. Geomatrix, Progress Report 2, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated July 5, 2006.

9. Geomatrix, Progress Report 3, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated March 30, 2007.

10. Geomatrix, Progress Report 4, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated March 28, 2008.

11. Geomatrix, Progress Report 5, Vulcan Materials Company Mission Valley Facility Rework Project, San Diego, California, dated June 1, 2009.

12. AMEX Geomatrix, Inc., Progress Report No. 6, Vulcan Materials Company, Mission Valley Facility Rework Project, San Diego, California, dated April 22, 2010.

http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html

LIST OF REFERENCES (Continued)

Project No. 06650-42-11 April 24, 2012

13. AMEX Geomatrix, Inc., Progress Report No. 7, Vulcan Materials Company, Mission Valley Facility Rework Project, San Diego, California, dated June 15, 2011.

14. Historic and Future Pit Floor, Mission Valley Plant, prepared by Vulcan Materials Company, dated February 7, 2008.

15. Jennings, C. W., 1994, California Division of Mines and Geology, Fault Activity Map of California and Adjacent Areas, California Geologic Data Map Series Map No. 6.

16. Kennedy, M. P. and S. S. Tan, 2005, Geologic Map of the San Diego 30’x60’ Quadrangle, California, USGS Regional Map Series Map No. 3, Scale 1:100,000.

17. Risk Engineering Company , EZ-FRISK, Version 7.62.

18. Unpublished reports and maps on file with Geocon Incorporated.

19. USGS computer program, Seismic Hazard Curves and Uniform Hazard Response Spectra.

Documents

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