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HomeMy WebLinkAboutEA 15-04; Calavera Hills Community Park; Administrative Permits (ADMIN) (3) GEOTECHNICAL EVALUATION CALAVERA HILLS GATEWAY IMPROVEMENTS CALAVERA HILLS COMMUNITY PARK 2997 GLASGOW DRIVE CARLSBAD, CALIFORNIA PREPARED FOR: City of Carlsbad 799 Pine Avenue, Suite 200 Carlsbad, California 92008 PREPARED BY: Ninyo & Moore Geotechnical and Environmental Sciences Consultants 5710 Ruffin Road San Diego, California 92123 February 13, 2015 Project No. 107544007 Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc i TABLE OF CONTENTS Page 1. INTRODUCTION....................................................................................................................1 2. SCOPE OF SERVICES............................................................................................................1 3. SITE AND PROJECT DESCRIPTION ...................................................................................1 4. PREVIOUS GEOTECHNICAL WORK..................................................................................2 5. SUBSURFACE EXPLORATION AND LABORATORY TESTING....................................3 6. GEOLOGY AND SUBSURFACE CONDITIONS.................................................................3 6.1. Regional Geologic Setting............................................................................................3 6.2. Site Geology.................................................................................................................4 6.2.1. Fill.......................................................................................................................4 6.2.2. Santiago Peak Volcanics.....................................................................................4 6.3. Groundwater.................................................................................................................5 6.4. Faulting and Seismicity................................................................................................5 6.4.1. Strong Ground Motion.........................................................................................5 6.4.2. Ground Rupture...................................................................................................6 6.4.3. Liquefaction and Seismically Induced Settlement..............................................6 6.5. Landsliding and Slope Stability....................................................................................7 7. CONCLUSIONS ......................................................................................................................7 8. RECOMMENDATIONS..........................................................................................................8 8.1. Earthwork .....................................................................................................................8 8.1.1. Site Preparation...................................................................................................8 8.1.2. Remedial Earthwork ...........................................................................................8 8.1.3. Temporary Excavations ......................................................................................9 8.1.4. Excavation Characteristics................................................................................10 8.1.5. Materials for Fill ...............................................................................................10 8.1.6. Compacted Fill..................................................................................................11 8.1.7. Utility Trench Backfill......................................................................................12 8.2. Seismic Design Parameters.........................................................................................12 8.3. Foundations.................................................................................................................13 8.3.1. Bearing Capacity...............................................................................................13 8.3.2. Lateral Resistance.............................................................................................14 8.3.3. Static Settlement ...............................................................................................14 8.3.4. Shade Structure and Light Pole Foundations....................................................14 8.4. Concrete Flatwork ......................................................................................................16 8.5. Corrosion....................................................................................................................16 8.6. Concrete......................................................................................................................17 8.7. Drainage......................................................................................................................17 8.8. Pre-Construction Conference......................................................................................18 8.9. Plan Review and Construction Observation...............................................................18 Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc ii 9. LIMITATIONS.......................................................................................................................18 10. REFERENCES.......................................................................................................................20 Table Table 1 – 2013 California Building Code Seismic Design Criteria...............................................13 Figures Figure 1 – Site Location Figure 2 – Test Pit Locations Figure 3 – Fault Locations Figure 4 – Geology Appendices Appendix A – Test Pit Logs Appendix B – Laboratory Testing Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 1 1. INTRODUCTION In accordance with your request and Purchase Order No. P129450 (dated January 13, 2015), we have performed a geotechnical evaluation for the proposed Calavera Hills Gateway Improve- ments project in Carlsbad, California (Figure 1). The project will be constructed within the City of Carlsbad’s Calavera Hills Community Park. This report presents the results of our field explo- ration and laboratory testing, our conclusions regarding the geotechnical conditions at the site, and our recommendations for the design and earthwork construction of this project. 2. SCOPE OF SERVICES The scope of services for this study included the following:  Review of readily available published and in-house geotechnical literature, preliminary site plan, topographic maps, geologic maps, fault maps, and stereoscopic aerial photographs.  Performing a field reconnaissance to observe existing site conditions and to locate and mark proposed exploratory test pit locations.  Performing a subsurface exploration that consisted of excavating, logging, and sampling three exploratory test pits using a backhoe. Bulk soil samples were obtained at selected in-tervals from the test pits. The collected samples were transported to our in-house geotechnical laboratory for analysis.  Performing geotechnical laboratory testing on selected soil samples to evaluate soil parame- ters for design purposes.  Geotechnical evaluation of field and laboratory data.  Preparation of this report presenting our findings, conclusions, and recommendations re- garding the geotechnical design and construction of the project. 3. SITE AND PROJECT DESCRIPTION Calavera Hills Community Park is located at 2997 Glasgow Drive in the City of Carlsbad, California (Figure 1). The park is situated on an irregularly shaped parcel bounded by Carlsbad Village Drive to the north, Tamarack Avenue to the west, Glasgow Drive to the east and southeast. The park was originally graded and constructed in 1987 (Rick Engineering, 1986; Leighton & Associates, 1987). Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 2 The site of the proposed Calavera Hills Gateway Improvements project is located in the northeast corner of the park on an approximately one-half-acre, rectangular parcel. The elevation at the pro- ject site is approximately 350 feet MSL to 355 feet MSL (USGS, 2012). Topographically, the site grades gently to the northwest towards Carlsbad Village Drive. Currently, the site of the proposed improvements is vacant and ground surface consists of bare soil. An existing slope up to approxi- mately 15 feet in height slopes down to the north up along the northern border of the site. Slopes of up to approximately 8 feet in height border the western and southern portions of the site and slope down to the southwest. The existing slopes that bound the project site are landscaped with ground cover, shrubs and trees. Based on our conversations with representatives of the City of Carlsbad and our review of the pro- ject’s conceptual plan (Wimmer, Yamada and Caughey, 2014), we understand that the proposed project will include the construction of a new park sign, a barbeque area, picnic tables, concrete seat walls and flatwork, park benches, fabric shade structures, workout equipment, and light poles. 4. PREVIOUS GEOTECHNICAL WORK The geotechnical conditions at the subject site were previously evaluated by Leighton & Associ- ates (1986a; 1986b) as part of the development of the existing Calavera Hills Park. At that time, the site of the Calavera Hills Gateway Improvement was originally planned to be developed with a fire station. Leighton & Associates (1986b) provided geotechnical recommendations for earth- work associated with the construction of the fire station. Rough and fine grading of the park (including that for the subject site) was subsequently performed under the observation and test- ing of Leighton & Associates (1987) and included remedial earthwork within the proposed building area for the fire station. Incomplete removals of undocumented fill were reportedly per- formed outside of the then-proposed building footprint for the fire station. The fire station was never constructed and the subject site has been vacant since it was graded. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 3 5. SUBSURFACE EXPLORATION AND LABORATORY TESTING Our subsurface exploration was conducted on January 16, 2015 and consisted of excavating, log- ging, and sampling of three exploratory test pits (TP-1 through TP-3). The test pits were excavated to approximate depths of up to 15 feet below existing grades using a backhoe. Bulk soil samples were obtained from the test pits at selected intervals. The samples were then transported to our in- house geotechnical laboratory for testing. The approximate locations of the exploratory test pits are shown on Figure 2. Test pit logs are included in Appendix A. Geotechnical laboratory testing of representative soil samples included in-situ moisture content, gradation, expansion index, and soil corrosivity. The results of the in-situ moisture content tests are presented on the test pit logs in Appendix A. The results of the other laboratory tests per- formed are presented in Appendix B. 6. GEOLOGY AND SUBSURFACE CONDITIONS Our findings regarding regional and site geology, groundwater conditions, faulting and seismicity, landslides, and other geologic hazards at the subject site are provided in the following sections. 6.1. Regional Geologic Setting The project area is situated in the western portion of the Peninsular Ranges Geomorphic Province. This geomorphic province encompasses an area that extends approximately 900 miles from the Transverse Ranges and the Los Angeles Basin south to the southern tip of Baja California (Norris and Webb, 1990; Harden, 1998). The province varies in width from approximately 30 to 100 miles and generally consists of rugged mountains underlain by Jurassic metavolcanic and metasedimentary rocks, and Cretaceous igneous rocks of the southern California batholith. The portion of the province in western San Diego County that includes the project area consists generally of uplifted and dissected coastal plain underlain by Upper Cretaceous-, Tertiary-, and Quaternary-age sedimentary rocks. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 4 The Peninsular Ranges Province is traversed by a group of sub-parallel faults and fault zones trending roughly northwest. Several of these faults are considered to be active. The Elsinore, San Jacinto, and San Andreas faults are active fault systems located northeast of the project area and the Rose Canyon, Coronado Bank, San Diego Trough, and San Clemente faults are active faults located west of the project area. The location of the site relative to these regional faults is shown on Figure 3. Major tectonic activity associated with these and other faults within this re- gional tectonic framework consists primarily of right-lateral, strike-slip movement. The Rose Canyon Fault Zone, the nearest active fault system, has been mapped approximately 7 miles west of the project site. 6.2. Site Geology The geology of the site vicinity is shown on Figure 4. Geologic units encountered during our subsurface exploration included fill and Santiago Peak Volcanics (Kennedy and Tan, 2005). Generalized descriptions of the earth units encountered during our field reconnaissance and subsurface exploration are provided in the subsequent sections. Additional descriptions of the subsurface units are provided on the test pit logs in Appendix A. A regional geologic map is included on Figure 4. 6.2.1. Fill Fill materials were encountered in our test pits from the ground surface to depths of up to ap- proximately 15 feet below existing grades. These materials were observed to generally consist of various shades of brown and gray, moist, soft to firm, sandy clay with varying amounts of silt, gravel, cobble, and boulders. Boulders up to 2 feet in diameter were encountered in the fill. Additionally, scattered organic material and construction debris, including concrete pieces and wood fragments, were encountered in the fill materials. 6.2.2. Santiago Peak Volcanics Mesozoic-age Santiago Peak Volcanics (mapped as Metasedimentary and Metavolcanic Rocks Undivided [Kennedy and Tan, 2005]) were encountered in test pits TP-2 and TP-3 underlying the fill to the total depth explored of each test pit, where refusal to the Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 5 backhoe excavating equipment was encountered at depths of 9.5 feet and 7 feet, respec- tively. The Santiago Peak Volcanics were observed to consist of various shades of brown, dry to moist, decomposed to moderately weathered metavolcanic rock. 6.3. Groundwater Groundwater was not encountered in our exploratory test pits during our evaluation. While not encountered during our subsurface exploration, seepage or perched water due to infiltration from irrigation of nearby landscape areas and leakage from existing storm drains may be en- countered during construction. Fluctuations in the groundwater level and perched conditions may occur due to variations in ground surface topography, subsurface geologic conditions and structure, rainfall, irrigation, and other factors. 6.4. Faulting and Seismicity Based on our review of the referenced geologic maps and stereoscopic aerial photographs, as well as on our geologic field mapping, the subject site is not underlain by known active or potentially active faults (i.e., faults that exhibit evidence of ground displacement in the last 11,000 years and 2,000,000 years, respectively). The site is not located within a State of California Earthquake Fault (Alquist-Priolo Special Studies) Zone. However, like the major- ity of southern California, the site is located in a seismically active area and the potential for strong ground motion is considered significant during the design life of the proposed struc- tures. The nearest known active fault is the Rose Canyon fault, located approximately 7 miles west of the site. 6.4.1. Strong Ground Motion The 2013 California Building Code (CBC) specifies that the Risk-Targeted, Maximum Considered Earthquake (MCER) ground motion response accelerations be used to evaluate seismic loads for design of buildings and other structures. The MCER ground motion response accelerations are based on the spectral response accelerations for 5 percent damping in the direction of maximum horizontal response and incorporate a Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 6 target risk for structural collapse equivalent to 1 percent in 50 years with deterministic limits for near-source effects. The horizontal peak ground acceleration (PGA) that corresponds to the MCER for the site was calculated as 0.43g using the United States Geological Survey (USGS, 2013) seismic design tool (web-based). Spectral response acceleration parameters, consistent with the 2013 CBC, are also provided in Section 7.2. for the evaluation of seismic loads on buildings and other structures. The 2013 CBC specifies that the potential for liquefaction and soil strength loss be evaluated, where applicable, for the Maximum Considered Earthquake Geometric Mean (MCEG) peak ground acceleration with adjustment for site class effects in accordance with the American Society of Civil Engineers (ASCE) 7-10 Standard. The MCEG peak ground acceleration is based on the geometric mean peak ground acceleration with a 2 percent probability of exceedance in 50 years. The MCEG peak ground acceleration with adjustment for site class effects (PGAM) was calculated as 0.41g using the USGS (USGS, 2013) seismic design tool that yielded a mapped MCEG peak ground acceleration of 0.41g for the site and a site coefficient (FPGA) of 1.0 for Site Class C. 6.4.2. Ground Rupture Based on our review of the referenced literature and our field evaluation, active faults are not known to cross the project vicinity. Therefore, the potential for ground rupture due to faulting at the site is considered low. However, lurching or cracking of the ground surface as a result of nearby seismic events is possible. 6.4.3. Liquefaction and Seismically Induced Settlement Liquefaction of cohesionless soils can be caused by strong vibratory motion due to earth- quakes. Research and historical data indicate that loose granular soils and non-plastic silts that are saturated by a relatively shallow groundwater table are susceptible to liquefaction. Based on the dense nature of the Santiago Peak Volcanics encountered in our test pits and the observed absence of shallow groundwater, it is our opinion that the potential for lique- faction and seismically induced settlement to occur at the site is not a design consideration. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 7 6.5. Landsliding and Slope Stability Based on our review of published geologic literature and aerial photographs, along with our subsurface evaluation, landslides or indications of deep-seated slope instability do not un- derlie and are not adjacent to the project site. 7. CONCLUSIONS Based on our review of the referenced background data, subsurface exploration, and laboratory testing, it is our opinion that construction of the proposed improvements for the Calavera Hills Community Park are feasible from a geotechnical standpoint provided the recommendations pre- sented in this report are incorporated into the design and construction of the project. In general, the following conclusions were made:  The project site is underlain by fill soils and Santiago Peak Volcanics. Portions of the fill materials are considered to be potentially compressible and are not suitable for structural support in their present condition. Recommendations for remedial earthwork are presented in the following sections.  Groundwater was not encountered during our subsurface exploration. Fluctuations in the groundwater level may occur due to variations in ground surface topography, subsurface ge- ologic conditions and structure, rainfall, irrigation, and other factors.  The active Rose Canyon fault zone is located approximately 7 miles west of the site. Ac- cordingly, the potential for relatively strong seismic ground motions should be considered in the project design.  The existing fill soils encountered on-site should be generally excavatable with heavy-duty earth moving equipment in good working condition. Zones containing gravel, cobble and boul- ders may be encountered and additional efforts including heavy ripping should be anticipated. Excavations extending into portions of the fill and Santiago Peak Volcanics will generate oversize material and additional processing and handling of these materials, including screen- ing and crushing, should be anticipated.  Drilling of holes into the Santiago Peak Volcanics (for shade structure and light pole founda-tions) will be difficult and can be expected to require coring or other special drilling methods. Excavations extending into materials of the Santiago Peak Volcanics will encounter very diffi- cult excavation conditions, and heavy ripping, coring, and/or blasting should be anticipated. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 8  On-site soils, other than materials with high organic content, are suitable for reuse as compacted fill, provided they meet the criteria mentioned in the fill materials section of this report.  Moisture conditioning and screening, crushing, and/or off site disposal of oversized mate- rials should be anticipated if on site materials are reused as fill.  Based on the results of our limited soil corrosivity tests, ACI 318, and Caltrans (2012) criteria, the site would be classified as a corrosive site, specifically with respect to ferrous metals. 8. RECOMMENDATIONS Based on our understanding of the project, the following recommendations are provided for the de- sign and construction of the proposed improvements. The proposed site improvements should be constructed in accordance with the requirements of the applicable governing agencies. 8.1. Earthwork In general, earthwork should be performed in accordance with the recommendations presented in this report. Ninyo & Moore should be contacted for questions regarding the recommenda- tions or guidelines presented herein. 8.1.1. Site Preparation Site preparation should begin with the removal of existing vegetation, utility lines, asphalt, concrete, and other deleterious debris from areas to be graded. Tree stumps and roots should be removed to such a depth that organic material is generally not present. Clearing and grubbing should extend to the outside of the proposed excavation and fill areas. The debris and unsuitable material generated during clearing and grubbing should be removed from ar- eas to be graded and disposed of at a legal dumpsite away from the project area. 8.1.2. Remedial Earthwork The existing fill materials at the site are considered potentially compressible and are not suitable to support settlement sensitive structures in their present condition. We recom- mend that the upper portions of the on-site fill materials be removed and replaced with compacted fill. The depth of these removals should extend 2 feet below existing grade or Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 9 one foot below the bottom of proposed shallow foundations (whichever is deeper). In general, remedial grading should extend 5 feet or more beyond the limit of the improve- ment, as practical. Ninyo & Moore should observe the overexcavation bottom prior to filling to evaluate the need for deeper removals. Deeper removals may be needed at spe- cific locations if loose, compressible, or otherwise unsuitable materials are exposed or encountered during grading. The resultant removal surface should be scarified to a depth of approximately 8 inches, moisture conditioned and recompacted to a relative compac- tion of 90 percent as evaluated by the ASTM International (ASTM) Test Method D 1557 prior to placing new fill. Subsequent to recompaction of the removal surface, the overexcavation should be backfilled with compacted fill placed in accordance with the recommendations contained in Section 7.1.6. 8.1.3. Temporary Excavations For temporary excavations, we recommend that the following Occupational Safety and Health Administration (OSHA) soil classifications be used: Fill Type C Santiago Peak Volcanics Type B Upon making the excavations, the soil classifications and excavation performance should be evaluated in the field by the geotechnical consultant in accordance with the OSHA regulations. Temporary excavations should be constructed in accordance with OSHA recommendations. For trenches or other excavations, OSHA requirements re- garding personnel safety should be met using appropriate shoring (including trench boxes) or by laying back the slopes to no steeper than 1.5:1 (horizontal: vertical) in en- gineered fill and 1:1 in Santiago Peak Volcanics. Temporary excavations that encounter seepage may be shored or stabilized by placing sandbags or gravel along the base of the seepage zone. Excavations encountering seepage should be evaluated on a case-by-case basis. On-site safety of personnel is the responsibility of the contractor. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 10 8.1.4. Excavation Characteristics The results of our field exploration program indicate that the project site, as presently pro- posed, is underlain by fill soils and Santiago Peak Volcanics. The fill soils should be generally excavatable with heavy-duty earth moving equipment in good working condition. Zones containing gravel, cobble, and boulders may be encountered and additional efforts including heavy ripping should be anticipated. Excavations extending into materials of the Santiago Peak Volcanics will encounter very difficult excavation conditions, and the con- tractor should be prepared to utilize heavy ripping, coring equipment, and/or blasting methods. Excavations (including utility trenches) extending into portions of the fill and Santiago Peak Volcanics will generate oversize material and additional processing and han- dling of these materials including screening and crushing should be anticipated. Drilling of holes within the Santiago Peak Volcanics can also be expected to be difficult and may re- quire the use of specialized equipment (such as core barrels) to advance to design depths. 8.1.5. Materials for Fill Materials for fill may be obtained from on-site excavations or they may be imported. On- site soils with an organic content of less than approximately 3 percent by volume (or 1 percent by weight), and expansion indices (EI) less than 50, are suitable for reuse as general fill material. Fill material should not contain rocks or lumps over approximately 3 inches in diameter, and not more than approximately 30 percent larger than ¾ inch. Oversize materials (greater than 3 inches in largest diameter), if encountered, should be separated from material to be used for compacted fill and removed from the site. Moisture conditioning (including drying) of existing on-site materials is anticipated if reused as fill. Imported fill materials should generally be granular soils with very low to low expan- sion potential (i.e., an expansion index of 50 or less as evaluated by ASTM D 4829). Imported fill material should also be tested for corrosive potential and exhibit a mini- mum resistivity value greater than 1,000 ohm-centimeters, chloride content of less than 500 parts per million (ppm), a sulfate content of less than 1,000 ppm and pH greater than 5.5. The contractor should be responsible for the uniformity of import material Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 11 brought to the site. We recommend that materials proposed for use as import fill be evaluated from a contractor’s stockpile rather than in place materials. Utility trench backfill material, outside the zone defined in the following sections, should not contain rocks or lumps over approximately 3 inches in general. In general, soils classified as silts or clays should not be used for backfill in the pipe zone. Larger chunks, if generated dur- ing excavation, may be broken into acceptably sized pieces or disposed of offsite. 8.1.6. Compacted Fill Prior to placement of compacted fill, the contractor should request an evaluation of the exposed ground surface by Ninyo & Moore. Unless otherwise recommended, the exposed ground surface should then be scarified to a depth of approximately 8 inches and watered or dried, as needed, to achieve moisture contents generally above the optimum moisture content. The scarified materials should then be com- pacted to a relative compaction of 90 percent as evaluated in accordance with ASTM D 1557. The evaluation of compaction by the geotechnical consultant should not be considered to preclude any requirements for observation or approval by governing agencies. It is the contractor's responsibility to notify this office and the appropriate governing agency when project areas are ready for observation, and to provide rea- sonable time for that review. Fill materials should be moisture conditioned to generally above the laboratory opti- mum moisture content prior to placement. The optimum moisture content will vary with material type and other factors. Moisture conditioning of fill soils should be generally consistent within the soil mass. Prior to placement of additional compacted fill material following a delay in the grading operations, the exposed surface of previously compacted fill should be prepared to receive fill. Preparation may include scarification, moisture conditioning, and recompaction. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 12 Compacted fill should be placed in horizontal lifts of approximately 8 inches in loose thickness. Prior to compaction, each lift should be watered or dried as needed to achieve a moisture content generally above the laboratory optimum, mixed, and then compacted by mechanical methods to a relative compaction of 90 percent as evaluated by ASTM D 1557. Successive lifts should be treated in a like manner until the desired finished grades are achieved. 8.1.7. Utility Trench Backfill Based on our subsurface evaluation, the on-site earth materials should be generally suit- able for re-use as trench backfill provided they are free of organic material, clay lumps, debris, and rocks greater than approximately 3 inches in diameter. Larger chunks, if generated during excavation, may be broken into acceptably sized pieces or disposed of off site. Soils classified as silts or clays should not be used for backfill in the pipe zone. Fill should be moisture-conditioned to generally above the laboratory optimum. Trench backfill should be compacted to a relative compaction of 90 percent as evaluated by ASTM D 1557 except for the upper 12 inches of the backfill below pavements that should be compacted to a relative compaction of 95 percent as evaluated by ASTM D 1557. Lift thickness for backfill will depend on the type of compaction equipment utilized, but fill should generally be placed in lifts not exceeding 8 inches in loose thickness. Special care should be exercised to avoid damaging the pipe during compaction of the backfill. 8.2. Seismic Design Parameters Design of the proposed improvements should be performed in accordance with the requirements of governing jurisdictions and applicable building codes. Table 1 presents the seismic design parameters for the site in accordance with the CBC (2013) guidelines and adjusted MCER spectral response acceleration parameters (USGS, 2013). Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 13 Table 1 – 2013 California Building Code Seismic Design Criteria Site Coefficients and Spectral Response Acceleration Parameters Values Site Class D Site Coefficient, Fa 1.000 Site Coefficient, Fv 1.387 Mapped Spectral Response Acceleration at 0.2-second Period, Ss 1.070 g Mapped Spectral Response Acceleration at 1.0-second Period, S1 0.413 g Spectral Response Acceleration at 0.2-second Period Adjusted for Site Class, SMS 1.070 g Spectral Response Acceleration at 1.0-second Period Adjusted for Site Class, SM1 0.573 g Design Spectral Response Acceleration at 0.2-second Period, SDS 0.713 g Design Spectral Response Acceleration at 1.0-second Period, SD1 0.382 g 8.3. Foundations The proposed improvements may be supported on shallow, spread, or continuous footings bearing on compacted fill. Foundations should be designed in accordance with structural considerations and the following recommendations. In addition, requirements of the appro- priate governing jurisdictions and applicable building codes should be considered in the design of the structures. 8.3.1. Bearing Capacity Shallow, spread, or continuous footings bearing on compacted fill may be designed us- ing an allowable bearing capacity of 1,500 pounds per square foot (psf). These allowable bearing capacities may be increased by one-third when considering loads of short duration such as wind or seismic forces. These allowable bearing capacities are based on a factor of safety of roughly three. Spread footings should be founded 18 inches below the lowest adjacent grade. Con- tinuous footings should have a width of 15 inches and isolated spread footings should be 24 inches in width. The spread footings should be reinforced in accordance with the recommendations of the project structural engineer. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 14 8.3.2. Lateral Resistance For resistance of footings to lateral loads bearing on compacted fill, we recommend an al- lowable passive pressure of 100 psf of depth be used with a value of up to 1,000 psf. This value assumes that the ground is horizontal for a distance of 10 feet, or three times the height generating the passive pressure, whichever is greater. We recommend that the up- per 1 foot of soil not protected by pavement or a concrete slab be neglected when calculating passive resistance. For sliding resistance to lateral loads, we recommend a cohesion of 130 psf be used between soil and concrete. The allowable lateral resistance can be taken as the sum of the sliding resistance (cohesion value multiplied by the contact area) and passive re- sistance provided the passive resistance does not exceed one-half of the total allowable resistance. The passive resistance values may be increased by one-third when considering loads of short duration such as wind or seismic forces. 8.3.3. Static Settlement We estimate that the proposed structures, designed and constructed as recommended herein, and founded in compacted fill will undergo total settlement on the order of 1 inch. Differential settlement on the order of ½ inch over a horizontal span of 40 feet can be expected. 8.3.4. Shade Structure and Light Pole Foundations The shade structures should be supported on cast-in-drilled-hole piles. Shade structures typically impose relatively light axial loads on foundations. Although we anticipate that pile dimensions will be generally controlled by the lateral or uplift load demand, we recommend that drilled shade structure foundations have a diameter of 12 inches or more. The pile dimensions (i.e., diameter and embedment) should be evaluated by the project structural engineer. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 15 The drilled pile construction should be observed by Ninyo & Moore during drilling to evaluate if the piles have been extended to the design depths. The drilled holes should be cleaned of loose soil and gravel. It is the contractor's responsibility to (a) take appropriate measures for maintaining the integrity of the drilled holes, (b) see that the holes are cleaned and straight, and (c) see that sloughed loose soil is removed from the bottom of the hole prior to the placement of concrete. Drilled piles should be checked for alignment and plumbness during installation. The amount of acceptable misalignment of a pile is approximately 3 inches from the plan location. It is usually acceptable for a pile to be out of plumb by 1 percent of the depth of the pile. The center-to-center spacing of piles should be no less than three times the nominal diameter of the pile. As discussed herein, foundations will experience difficult drilling conditions. In addi- tion, portions of the fill are anticipated to contain cobbles and boulders. In these materials, specialized drilling methods (such as the use of core barrels or air rotary drilling equipment) may be needed to advance the holes to the desired depths. For resistance of shade structure foundations to lateral loads, we recommend an allowable passive pressure of 200 psf per foot of depth be used with a value of up to 2,000 psf within the fill soils. Where the foundations extend into the Santiago Peak Volcanics, an allowable passive resistance of 400 psf per foot of embedment can be used with a value of up to 4,000 psf. These values assume that the shade structures are designed to tolerate ½ inch of deflection at the surface and that the ground is horizontal for a distance of 10 feet, or three times the height generating the passive pressure, whichever is greater. We recommend that the upper 1 foot of soil not protected by pavement or a concrete slab be neglected when calculating passive resistance. For sliding resistance to lateral loads, we recommend a cohesion of 130 psf be used be- tween fill soils and concrete, and a coefficient of friction of 0.35 between the Santiago Peak Volcanics and concrete. The allowable lateral resistance can be taken as the sum of the sliding resistance (cohesion value multiplied by the contact area) and passive resis- tance provided the passive resistance does not exceed one-half of the total allowable Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 16 resistance. The passive resistance values may be increased by one-third when consider- ing loads of short duration such as wind or seismic forces. 8.4. Concrete Flatwork Exterior concrete flatwork should be 4 inches in thickness for pedestrian pavements and 5 inches in thickness for light duty vehicular pavement, and should be reinforced with No. 3 reinforcing bars placed at 24 inches on-center both ways. Exterior slabs should be underlain by 4 inches of clean sand. To reduce the potential manifestation of distress to exterior con- crete flatwork due to movement of the underlying soil, we recommend that such flatwork be installed with crack-control joints at appropriate spacing as designed by the structural engi- neer. Before placement of concrete, the subgrade soils should be scarified to a depth of 12 inches, moisture conditioned to generally above the laboratory optimum moisture con- tent, and compacted to a relative compaction of 90 percent as evaluated by ASTM D 1557. Positive drainage should be established and maintained adjacent to flatwork. Recommenda- tions for flexible or rigid pavement sections can be provided upon request. 8.5. Corrosion Laboratory testing was performed on representative samples of the on-site earth materials to evaluate pH and electrical resistivity, as well as chloride and sulfate contents. The pH and electrical resistivity tests were performed in accordance with CT 643 and the sulfate and chloride content tests were performed in accordance with CT 417 and CT 422, respectively. These laboratory test results are presented in Appendix B. The results of the corrosivity testing indicated electrical resistivity of 700 ohm-cm, soil pH of 7.2, chloride content of 780 ppm, and sulfate content of 0.030 percent (i.e., 300 ppm). Based on the American Concrete Institute (ACI) 318 and Caltrans corrosion (2012) criteria, the site would be classified as a corrosive site, particularly with respect to ferrous metals. Corrosive soils are generally defined as soils with electrical resistivities less than 1,000 ohm-cm, more than 500 ppm chlorides, more than 0.2 percent sulfates, or a pH less than 5.5. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 17 8.6. Concrete Concrete in contact with soil or water that contains high concentrations of soluble sulfates can be subject to chemical deterioration. Laboratory testing indicated a sulfate content of the sample tested of 0.030 percent (i.e., 300 ppm). According to the ACI 318, the potential for sulfate attack is negligible for water-soluble sulfate content of up to about 0.10 percent by weight (i.e., 1,000 ppm) in soils. Therefore, the site soils may be considered to have a negli- gible potential for sulfate attack. Based on ACI criteria, Type II cement may be used for concrete construction. However, due to the potential variability of site soils, consideration should be given to using Type II/V cement and concrete with a water-cement ratio no higher than 0.45 by weight for normal weight aggregate concrete for the project. 8.7. Drainage Pad and slope drainage should be conveyed such that runoff water is diverted away from slopes and structures to suitable discharge areas by nonerodible devices (e.g., gutters, downspouts, concrete swales, etc.). Positive drainage adjacent to structures should be established and maintained. Positive drainage may be accomplished by providing drainage away from the foundations of the structure at a gradient of 5 percent or steeper for a distance of 10 feet or more outside the building perimeter, or 2 percent or steeper for a distance of 10 feet or more outside the building perimeter if paved. Drainage should be further maintained by a graded swale leading to an appropriate outlet, in accordance with the recommendations of the project civil engineer and/or landscape architect. Surface drainage on the site should be provided so that water is not permitted to pond. A gradient of 2 percent or steeper should be maintained over the pad area and drainage patterns should be established to divert and remove water from the site to appropriate outlets. Care should be taken by the contractor during final grading to preserve any berms, drainage ter- races, interceptor swales or other drainage devices of a permanent nature on or adjacent to the property. Drainage patterns established at the time of final grading should be maintained for the life of the project. The property owner and the maintenance personnel should be made aware that altering drainage patterns might be detrimental to slope stability and foundation performance. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 18 8.8. Pre-Construction Conference We recommend that a pre-construction meeting be held prior to commencement of grading. The owner or his representative, the agency representatives, the architect, the civil engineer, Ninyo & Moore, and the contractor should attend to discuss the plans, the project, and the proposed construction schedule. 8.9. Plan Review and Construction Observation The conclusions and recommendations presented in this report are based on analysis of ob- served conditions in widely spaced exploratory test pits. If conditions are found to vary from those described in this report, Ninyo & Moore should be notified, and additional recommen- dations will be provided upon request. Ninyo & Moore should review the final project drawings and specifications prior to the commencement of construction. Ninyo & Moore should perform the needed observation and testing services during construction operations. The recommendations provided in this report are based on the assumption that Ninyo & Moore will provide geotechnical observation and testing services during construction. In the event that it is decided not to utilize the services of Ninyo & Moore during construction, we request that the selected consultant provide the client with a letter (with a copy to Ninyo & Moore) indicating that they fully understand Ninyo & Moore’s recommendations, and that they are in full agreement with the design parameters and recommendations contained in this report. Construction of proposed improvements should be performed by qualified subcon- tractors utilizing appropriate techniques and construction materials. 9. LIMITATIONS The field evaluation, laboratory testing, and geotechnical analyses presented in this report have been conducted in general accordance with current practice and the standard of care exercised by geotech- nical consultants performing similar tasks in the project area. No warranty, expressed or implied, is made regarding the conclusions, recommendations, and opinions presented in this report. There is no evaluation detailed enough to reveal every subsurface condition. Variations may exist and conditions Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 19 not observed or described in this report may be encountered during construction. Uncertainties rela- tive to subsurface conditions can be reduced through additional subsurface exploration. Additional subsurface evaluation will be performed upon request. Please also note that our evaluation was lim- ited to assessment of the geotechnical aspects of the project, and did not include evaluation of structural issues, environmental concerns, or the presence of hazardous materials. This document is intended to be used only in its entirety. No portion of the document, by itself, is designed to completely represent any aspect of the project described herein. Ninyo & Moore should be contacted if the reader requires additional information or has questions regarding the content, interpretations presented, or completeness of this document. This report is intended for design purposes only. It does not provide sufficient data to prepare an accurate bid by contractors. It is suggested that the bidders and their geotechnical consult- ant perform an independent evaluation of the subsurface conditions in the project areas. The independent evaluations may include, but not be limited to, review of other geotechnical re- ports prepared for the adjacent areas, site reconnaissance, and additional exploration and laboratory testing. Our conclusions, recommendations, and opinions are based on an analysis of the observed site conditions. If geotechnical conditions different from those described in this report are encountered, our office should be notified, and additional recommendations, if warranted, will be provided upon request. It should be understood that the conditions of a site could change with time as a result of natural processes or the activities of man at the subject site or nearby sites. In addition, changes to the applicable laws, regulations, codes, and standards of practice may occur due to government ac- tion or the broadening of knowledge. The findings of this report may, therefore, be invalidated over time, in part or in whole, by changes over which Ninyo & Moore has no control. This report is intended exclusively for use by the client. Any use or reuse of the findings, conclu- sions, and/or recommendations of this report by parties other than the client is undertaken at said parties’ sole risk. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 20 10. REFERENCES American Concrete Institute (ACI), 2014, ACI 318 Building Code Requirements for Structural Concrete and Commentary. Anderson, J. G., Rockwell, T. K., and Agnew, D. C., 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region: Earthquake Engineering Research Institute (EERI), Earthquake Spectra, Volume 5, No. 2. Building News, 2012, “Greenbook,” Standard Specifications for Public Works Construction: BNI Publications. California Building Standards Commission, 2013, California Building Code (CBC), Title 24, Part 2, Volumes 1 and 2. California Department of Transportation (Caltrans), 2012, Corrosion Guidelines (Version 2.0), Divi-sion of Engineering and Testing Services, Corrosion Technology Branch: dated November. California Geological Survey, 1998, Maps of Known Active Fault Near-Source Zones in Califor- nia and Adjacent Portions of Nevada. California Geological Survey (CGS), 2008a, Guidelines for Evaluating and Mitigating Seismic Hazards in California, CGS Special Publication 117A. California Geological Survey, 2008b, Earthquake Shaking Potential Map of California: Map Sheet 48 (revised). Cao, T., Bryant, W. A., Rowshandel, B., Branum, D., and Willis, C. J., 2003, The Revised 2002 California Probabilistic Seismic Hazards Maps: California Geological Survey. County of San Diego, 1963, Ortho-topographic Survey, Sheet 362-1677, Scale 1:24,000. County of San Diego, 1975, Topographic Survey, Sheet 362-1677, Scale 1:24,000. Google Earth, 2014, https://www.google.com/earth/. Harden, D. R., 1998, California Geology: Prentice Hall, Inc. Jennings, C. W. and Bryant, W. A., 2010, Fault Activity Map of California and Adjacent Areas: California Geological Survey, California Geological Map Series, Map No. 6. Kennedy, M. P. and Tan, S. S, 2005, Geologic Map of the Oceanside 30’ x 60’ Quadrangle, Cali- fornia: California Geological Survey, Scale 1:100,000. Leighton & Associates, 1986a, Supplemental Geotechnical Reconnaissance and Grading Plan Review, Calavera Hills Park Site, Carlsbad, California: dated October 21. Leighton & Associates, 1986b, Geotechnical Evaluation of Fill Soils Along Elm Avenue, Calav-era Hills Park Site, Carlsbad, California: dated November 24. Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc 21 Leighton & Associates, 1987, As-Graded Report of Rough and Post-Grading Operations for the Calavera Hills Community Park Site, Phases I and II, Carlsbad, California: dated October 7. Ninyo & Moore, In-house Proprietary Data. Norris, R. M. and Webb, R. W., 1990, Geology of California, Second Edition: John Wiley & Sons, Inc. Rick Engineering, 1986, Grading Plans for Calavera Park Site (CUP-266), City of Carlsbad, California. Rockwell, T. K., Lindvall, S. C. Haraden, C. C., Hirabayashi, C. K., and Baker, E., 1991, Mini-mum Holocene Slip Rate for the Rose Canyon Fault in San Diego, California in Abbott, P.L. and Elliott, W.J., eds., Environment Perils, San Diego Region: San Diego Associa- tion of Geologists. Tan, S.S., and Giffen, D.G., 1995, Landslide Hazards in the Northern Part of the San Diego Met- ropolitan Area, San Diego County, California, California Geological Survey, Landslide Hazard Identification map No. 35, Open File Report 95-03, Scale 1:24.000. Treiman, J. A., 1993, The Rose Canyon Fault Zone, Southern California: California Geological Survey, Open File Report 93-02. United States Department of the Interior, Bureau of Reclamation, 1989, Engineering Geology Field Manual. United States Geological Survey, 1949, San Luis Rey, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 1997, San Luis Rey, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 2008, National Seismic Hazard Maps - Fault Parameters, World Wide Web, http://geohazards.usgs.gov/cfusion/hazfaults_search/. United States Geological Survey, 2012, San Luis Rey, California Quadrangle Map, 7.5 Minute Series: Scale 1:24,000. United States Geological Survey, 2013, Ground Motion Parameter Calculator, World Wide Web, http://geohazards.usgs.gov/designmaps/us/application.php. Wimmer, Yamada and Caughey, 2014, Concept C' Site Plan, Calavera Hills Community Park, Northeast Lot Enhancements, Carlsbad, California: dated September 25. AERIAL PHOTOGRAPHS Source Date Flight Numbers Scale USDA April 11, 1953 AXN-8M 103 and 104 1:24,000 SOURCE: 2008 THOMAS GUIDE FOR SAN DIEGO COUNTY, STREET GUIDE AND DIRECTORY; MAP © RAND MCNALLY, R.L.07-S-129 NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 1_107544007_SL.mxd"SITE §¨¦8§¨¦8 §¨¦5§¨¦5 §¨¦15 §¨¦805§¨¦805 §¨¦215§¨¦215 MAP INDEX San DiegoCounty 0 2,400 4,8001,200 SCALE IN FEET CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE CARLSBAD, CALIFORNIA SITE LOCATION FIGURE 1PROJECT NO.DATE 107544007 2/15 ± ± NOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE LEGEND TEST PIT TD=TOTAL DEPTH IN FEET 0 50 10025 SCALE IN FEET ED TEST PIT LOCATIONS FIGURE 2PROJECT NO.DATE 2_107544007_TPL.mxd AOBSOURCE: 2012 SAN DIEGO IMAGERY ACQUISITION PARTNERSHIP (FLIGHT DATES: MAY 20 - JUNE 6, 2012) TP-3 TD=7.0 TP-1 TD=15.0 107544007 2/15 ED ED TP-2 TD=9.5 TP-3 TD=7.0 CARLSBAD VI L L A G E D RI V E GLASGOW DR IVE ED CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE CARLSBAD, CALIFORNIA !!!!! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! !! ! ! ! ! ! ! ! ! ! ! ! M E X I C O U S AP a c i f i c O c e a n SAN JACINTO ELSINORE IM P E RIA L WHITTIER SAN ANDREAS NEW PORT-INGLEWOOD C O R O N A D O B A N K S A N DIE G O T R O U G H SAN CLEMENTE S A N T A C RUZ-SANTA CATALINA RIDGE P A L O S VERDES OF F S H O R E Z O N E OF D E F O R M A T I O NGARLOCKWHITE WOLFCLEARWATERS A N GABRIEL SIERRA MADRE BANNING MISSION CREEK BLA C K W A TE RHARPER LOCKHART LEN W O O D CAMP ROCK CALIC O LUDLOW PIS GAHBULLION M O U N T AIN JO HN S O N VALLEY EM ERSO N P IN T O M O UNTAINMANIX MIRAGE VALLEY NORTHHELENDALE FRONTAL CHINO S A N J O S ECUCAMON G A MALIBU COAS T SA N T A MONICA SANCAYETANO SANTASUSANASIMI-S A N T A R O S A N O R T H R ID G E C HA RN O C K S A W P ITCAN Y O N SUPERSTITION HILLS NEVADA CALIFORNIA R O S E C A N YONSan Bernardino County Kern County Riverside CountySan Diego County Imperial County Los Angeles County V e n t u r a C o u n t y Or a n g e C o u n t y Riverside CountySan Bernardino CountyL o s A n g e l e s C o u n t y Kern CountyIndioIrvine Pomona Mojave Anaheim Barstow Temecula Palmdale El CentroSanDiego Escondido Oceanside SantaAna Riverside Tehachapi Long Beach Wrightwood ChulaVista Los Angeles Victorville SanClemente PalmSprings Big Bear CityThousandOaksSanBernardino LakeArrowhead Twentynine Palms Baker DesertCenter ! ! CALIFORNIA 0 30 60 SCALE IN MILES LEGEND HOLOCENE ACTIVE CALIFORNIA FAULT ACTIVITY HISTORICALLY ACTIVE LATE QUATERNARY (POTENTIALLY ACTIVE) STATE/COUNTY BOUNDARY QUATERNARY (POTENTIALLY ACTIVE)"SITE !3_107544007_F.mxd AOBNOTE: DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE. FAULT LOCATIONS FIGURE 3PROJECT NO.DATE ± SOURCE: JENNINGS, C.W., AND BRYANT, W.A., 2010, FAULT ACTIVITY MAP OF CALIFORNIA, CALIFORNIA GEOLOGICAL SURVEY. 107544007 2/15 CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE CARLSBAD, CALIFORNIA NOTES: ALL DIRECTIONS, DIMENSIONS AND LOCATIONS ARE APPROXIMATE 0 1,750 3,500 SCALE IN FEET GEOLOGY FIGURE 4PROJECT NO.DATE4_107544007_G.mxd AOB± SOURCE: KENNEDY, M.P., AND TAN, S.S., 2005, GEOLOGIC MAP OF THE OCEANSIDE 30' X 60' QUADRANGLE, CALIFORNIA."SITE LEGEND OLD ALLUVIAL FLOOD PLAIN DEPOSITSQoa SANTIAGO FORMATIONTsa Qa Kt LANDSLIDE DEPOSITS ALLUVIAL FLOOD PLAIN DEPOSITSQa * * * * *** ** * * ** * * * * * ** * * ** * * * * ** * * * * Qls OLD PARALIC DEPOSITS, UNIT 10-11Qop10-11 DACITE STOCKTda Mzu TONALITEKt STRIKE AND DIP OF BEDS, INCLINED U D FAULT - SOLID WHERE ACCURATELYLOCATED, DASHED WHERE APPROXIMATE, DOTTED WHERE CONCEALED. ARROW AND NUMBER INDICATE DIRECTION AND ANGLE OF DIP OF FAULT PLANE 65 8 Qa Tsa Qoa 107544007 2/15 Tsa Qvop10-11 Kl Kt METASEDIMENTARY AND METAVOLCANICROCKS UNDIVIDED Tda Kl LUSARDI FORMATION Qls CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE CARLSBAD, CALIFORNIA Calavera Hills Gateway Improvements February 13, 2015 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc APPENDIX A TEST PIT LOGS Field Procedure for the Collection of Disturbed Samples Disturbed soil samples were obtained in the field using the following method. Bulk Samples Bulk samples of representative earth materials were obtained from the exploratory test pits. The samples were bagged and transported to the laboratory for testing. 0FILL:Bulk sample.Dashed line denotes material change.Drive sample.Sand cone performed.SeepageNo recovery with drive sampler.Groundwater encountered after excavation.Sample retained by others.No recovery with Shelby tube sampler.ALLUVIUM:Solid line denotes unit change.Attitude: Strike/Dipb:Beddingc: Contactj: Jointf: FractureF:Faultcs: Clay Seams: Shearbss: Basal Slide Surfacesf: Shear Fracturesz: Shear Zonesbs: Sheared Bedding SurfaceGroundwater encountered during excavation.Explanation of Test Pit, Core, Trench and Hand Auger Log SymbolsEXCAVATION LOG EXPLANATION SHEETFIGURE345 SCALE: 1 inch = 1 footSMSMML12xx/xxSand ConeDRY DENSITY (PCF)MOISTURE (%)CLASSIFICATIONU.S.C.S.SAMPLESPROJECT NO.DEPTH (FEET)Shelby tube sample. Distance pushed in inches/length of sample recovered in inchesThe total depth line is a solid line that is drawn at the bottom of the excavation log.DATEBulkDrivenTestpit explanation.xls 048121620240481216202418.716.1CLFILL:Dark brown, moist, soft, fine sandy CLAY; with organics; trace gravel.Gray, soft to firm, fine to medium sand; silty; scattered organics.@ 3.0': Scattered gravel and cobble.Brown, firm, fine to medium sand with gravel; scattered cobble and organics.@ 9': Boulders up to 24 inches in diameter. Difficult excavation.Scattered construction debris (wooden stake).Total Depth = 15 feet.Groundwater not encountered.Backfilled on 1/16/15 shortly after excavation.Note: Groundwater, though not encountered at the time of drilling, may rise toa higher level due to seasonal variations in precipitation and several otherfactors as discussed in the report.The ground elevation shown above is an estimation only. It is based on ourinterpretations of published maps and other documents reviewed for thepurposes of this evaluation. It is not sufficiently accurate for preparingconstruction bids and design documents.SCALE = 1 in./4 ft.107544007TEST PIT LOG CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE, CARLSBAD, CALIFORNIAPROJECT NO.2/15DATEDEPTH (FEET) Bulk SAMPLESDriven Sand Cone MOISTURE (%) DRY DENSITY (PCF) CLASSIFICATION U.S.C.S.DESCRIPTIONDATE EXCAVATED1/16/15TEST PIT NO.TP-1GROUND ELEVATION352' ± (MSL)LOGGED BYCKVMETHOD OF EXCAVATION310 JD BackhoeLOCATIONSee Figure 2FIGURE A-1 048121620240481216202410.313.4CLFILL:Brown, moist, soft, fine to medium sandy CLAY; with organics; trace gravel.Gray, soft to firm; scattered gravel and organics; scattered construction debris(wooden stake).@ 5': Cobble up to 12 inches in diameter.Brown, firm with gravel; scattered cobble and organics.METAVOLCANIC ROCK:Light reddish brown, dry to moist, intensely weathered METAVOLCANICROCK.Total Depth = 9.5 feet. (Refusal)Groundwater not encountered.Backfilled on 1/16/15 shortly after excavation.Note: Groundwater, though not encountered at the time of drilling, may rise toa higher level due to seasonal variations in precipitation and several otherfactors as discussed in the report.The ground elevation shown above is an estimation only. It is based on ourinterpretations of published maps and other documents reviewed for thepurposes of this evaluation. It is not sufficiently accurate for preparingconstruction bids and design documents.SCALE = 1 in./4 ft.107544007TEST PIT LOG CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE, CARLSBAD, CALIFORNIAPROJECT NO.2/15DATEDEPTH (FEET) Bulk SAMPLESDriven Sand Cone MOISTURE (%) DRY DENSITY (PCF) CLASSIFICATION U.S.C.S.DESCRIPTIONDATE EXCAVATED1/16/15TEST PIT NO.TP-2GROUND ELEVATION351' ± (MSL)LOGGED BYCKVMETHOD OF EXCAVATION310 JD BackhoeLOCATIONSee Figure 2FIGURE A-2 048121620240481216202417.0CLFILL:Brown, moist, soft, fine to medium sandy CLAY; scattered gravel andorganics.Gray, firm, fine to medium sand; silty; scattered gravel, cobble, organics; andconstruction debris (concrete pieces, wooden stake).@ 3': Brown; boulders up to 24 inches in diameter. Difficult excavation.METAVOLCANIC ROCK:Grayish brown, moist, intensely to moderately weathered, METAVOLCANICROCK.@ 6.5': Very moist.Total Depth = 7 feet. (Refusal)Groundwater not encountered.Backfilled on 1/16/15 shortly after excavation.Note: Groundwater, though not encountered at the time of drilling, may rise toa higher level due to seasonal variations in precipitation and several otherfactors as discussed in the report.The ground elevation shown above is an estimation only. It is based on ourinterpretations of published maps and other documents reviewed for thepurposes of this evaluation. It is not sufficiently accurate for preparingconstruction bids and design documents.SCALE = 1 in./4 ft.107544007TEST PIT LOG CALAVERA HILLS GATEWAY IMPROVEMENTS 2997 GLASGOW DRIVE, CARLSBAD, CALIFORNIAPROJECT NO.2/15DATEDEPTH (FEET) Bulk SAMPLESDriven Sand Cone MOISTURE (%) DRY DENSITY (PCF) CLASSIFICATION U.S.C.S.DESCRIPTIONDATE EXCAVATED1/16/15TEST PIT NO.TP-3GROUND ELEVATION351' ± (MSL)LOGGED BYCKVMETHOD OF EXCAVATION310 JD BackhoeLOCATIONSee Figure 2FIGURE A-3 Calavera Hills Community Park February 13, 2014 2997 Glasgow Drive, Carlsbad, California Project No. 107544007 107544007 R.doc APPENDIX B LABORATORY TESTING Classification Soils were visually and texturally classified in accordance with the Unified Soil Classification System (USCS) in general accordance with ASTM D 2488. Soil classifications are indicated on the logs of the exploratory test pits in Appendix A. Moisture Content The moisture content of samples obtained from the exploratory excavations was evaluated in ac- cordance with ASTM D 2216. The test results are presented on the logs of the exploratory excavations in Appendix A. Gradation Analysis Gradation analysis test were performed on a selected representative soil samples in general accor- dance with ASTM D 422. The grain-size distribution curves are shown on Figures B-1 through B-3. These test results were utilized in evaluating the soil classifications in accordance with the USCS. Expansion Index Test The expansion index of selected material was evaluated in general accordance with ASTM D 4829. The specimen was molded under a specified compactive energy at approximately 50 percent saturation. The prepared 1-inch thick by 4-inch diameter specimen was loaded with a surcharge of 144 pounds per square foot and was inundated with tap water. Readings of volumet- ric swell were made for a period of 24 hours. The results of this test are presented on Figure B-4. Soil Corrosivity Tests Soil pH, and minimum resistivity tests were performed on representative samples in general accor- dance with CT 643. The sulfate and chloride content of the selected samples were evaluated in general accordance with CT 417 and CT 422, respectively. The test results are presented on Figure B-5.