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Home My WebLink AboutCT 2019-0006; 2690 ROOSEVELT; GEOTECHNICAL INVESTIGATION; 2019-04-18GEOTECHNICAL INVESTIGATION 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA PREPARED FOR ~TCHELLDEVELOPMENTCOMPANY DEL MAR, CALIFORNIA APRIL 8, 2019 PROJECT NO. G2245-52-01 GEOCON INCORPORATED GEOTECHNIC Al ■ ENVIRONMENTAL ■ MATERIALSO Project No. 02245-52-01 April 8, 2019 Kitchell Development Company 1555 Camino Del Mar, Suite 307 Del Mar, California 92014 Attention: Subject: Mr. Mame Bouillon GEOTECHNICAL INVESTIGATION 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA Dear Mr. Bouillon: In accordance with your authorization of our Proposal No. LG-17436, we herein submit the results of our geotechnical investigation for the subject site. The accompanying report presents the results of our study and conclusions and recommendations pertaining to the geotechnical aspects of the proposed residential development. The site is considered suitable for development provided the recommendations of this report are followed. Should you have questions regarding this report, or ifwe may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON IN CORPORA TED ~:6-- RCE 8322 ( e-mail) Addressee 6960 Flanders Drive ■ San Diego; Califotnia 92121:-2974! ■ Telephone 858.558.6900 ■ Fax 858.558 .. 6159 TABLE OF CONTENTS 1. PURPOSE AND SCOPE ...................................................................................................................... 1 2. SITE AND PROJECT DESCRIPTION ................................................................................................ 1 3. GEOLOGIC SETTING ......................................................................................................................... 2 4. SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 2 4.1 Undocumented Fill (Qudf) ......................................................................................................... 3 4.2 Old Paralic Deposits (Qop) ......................................................................................................... 3 4.3 Santiago Formation (Tsa) ........................................................................................................... 3 5. GROUNDWATER ............................................................................................................................... 3 6. GEOLOGIC HAZARDS ...................................................................................................................... 4 6.1 Faulting and Seismicity .............................................................................................................. 4 6.2 Ground Rupture .......................................................................................................................... 5 6.3 Liquefaction ................................................................................................................................ 6 6.4 Seiches and Tsunamis ................................................................................................................. 6 6.5 Landslides ................................................................................................................................... 6 7. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 7 7 .1 General. ....................................................................................................................................... 7 7 .2 Excavation and Soil Characteristics ........................................................................................... 8 7 .3 Seismic Design Criteria .............................................................................................................. 9 7.4 Temporary Excavations ............................................................................................................ 11 7.5 Grading ..................................................................................................................................... 11- 7.6 Shallow Foundations ................................................................................................................ 12 7.7 Concrete Slabs-On-Grade ............................................................ _ ............................................. 15 7 .8 Concrete Flatwork .................................................................................................................... 16 7.9 Retaining Walls ........................................................................................................................ 18 7 .10 Lateral Loading ......................................................................................................................... 20 7 .11 Preliminary Pavement Recommendations ................................................................................ 20 7 .12 Site Drainage and Moisture Protection ..................................................................................... 25 7 .13 Grading and Foundation Plan Review ...................................................................................... 26 LIMITATIONS AND UNIFORMITY OF CONDITIONS MAPS AND ILLUSTRATIONS Figure 1, Vicinity Map Figure 2, Geologic Map Figure 3, Wall/Column Footing Dimension Detail Figure 4, Retaining Wall Loading Diagram Figure 5, Typical Retaining Wall Drain Detail TABLE OF CONTENTS (Concluded) APPENDIX A FIELD INVESTIGATION Figures A-1 -A-5, Logs of Borings APPENDIXB LABORATORY TESTING Table B-I, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results Table B-11, Summary of Laboratory Direct Shear Test Results Table B-111, Summary of Laboratory Expansion Index Test Results Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results Table B-V, Summary of Laboratory Unconfined Compressive Strength Test Results Figure B-1, Gradation Curves Figures B-2 -B-3, Consolidation Curves APPENDIXC STORM WATER MANAGEMENT INVESTIGATION APPENDIXD RECOMMENDED GRADING SPECIFICATIONS LIST OF REFERENCES GEOTECHNICAL INVESTIGATION 1. PURPOSE AND SCOPE This report presents the results of our geotechnical investigation for the planned residential development located at 2690 Roosevelt Street in the City of Carlsbad, California (see Vicinity Map, Figure 1 ). The purpose of the geotechnical investigation is to evaluate the surface and subsurface soil conditions and general site geology, and to identify geotechnical constraints that may affect development of the property including faulting, liquefaction and seismic shaking based on the 2016 CBC seismic design criteria. In addition, we provided recommendations for remedial grading, shallow foundations, concrete slab-on-grade, concrete flatwork, preliminary pavement, and retaining walls. The scope of this investigation also included a review of readily available published and unpublished geologic literature (see List of References). The scope of this investigation included performing a site reconnaissance, field exploration, engineering analyses and preparing this report. We performed our field investigation on February 1, 2018 by advancing 5 small-diameter borings to a maximum depth of approximately 19½ feet below the existing ground surface. The Geologic Map, Figure 2, presents the approximate locations of the I borings. Appendix A provides a detailed discussion of the field investigation including logs of the borings. Details of the laboratory tests and a summary of the test results are presented in Appendix B and on the boring logs in Appendix A. Appendix C presents the results of the storm water investigation to help evaluate proposed storm water management devices. Recommendations presented herein are based on analyses of data obtained from our site investigation and our understanding of proposed site development. References reviewed to prepare this report are provided in the List of References. If project details vary significantly from those described herein, Geocon should be contacted to evaluate the necessity for review and possible revision of this report. 2. SITE AND PROJECT DESCRIPTION The subject site is located north of the intersection of Roosevelt Street and Beech A venue in a residential area in the City of Carlsbad, California. The site currently consists of a single-family residence that has been modified to commercial space. The site is accessed from Roosevelt Street by a concrete drive to north and a gravel driveway to the south of the structure with parking available to the east of the building. The property slopes gently to the northwest with elevations ranging from about 41 to 47 feet above Mean Sea Level (MSL). Overhead utility lines exist fronting Roosevelt Street. We understand proposed development will consist of demolishing the existing structure and constructing four, 3-story, residential buildings consisting of 10 units with accommodating garages, driveways, utilities, landscaping and hardscape. The planned ground floor elevations of the buildings Project No. 02245-52-0 l - l -April 8, 2019 will range from approximately 42.6 to 44.4 feet MSL. We expect cuts and fills less than approximately 3 feet will be required to achieve planned grades, and we expect the planned structures will be supported on shallow foundations with a concrete-slab-on-grade. The site descriptions and proposed development are based on a site reconnaissance, review of published geologic literature, our field investigation, a review of preliminary architectural and grading plans, and discussions with you. If development plans differ from those described herein, Geocon should be contacted for review of the plans and possible revisions to this report. 3. GEOLOGIC SETTING The site is located in a coastal plain environment within the southern portion of the Peninsular Ranges Geomorphic Province of southern California. The Peninsular Ranges is a geologic and geomorphic province that extends from the Imperial Valley to the Pacific Ocean and from the Transverse Ranges to the north and into Baja California to the south. The coastal plain of San Diego County is underlain by a thick sequence of relatively undisturbed and non-conformable sedimentary rocks that thicken to the west and range in age from Upper Cretaceous through the Pleistocene with intermittent deposition. The sedimentary units are deposited on bedrock, Cretaceous to Jurassic age igneous and metavolcanic rocks. Geomorphically, the coastal plain is characterized by a series of 21 stair-stepped, marine terraces which are younger to the west and have· been dissected by west flowing rivers that drain the Peninsular Ranges to the east. The coastal plain is a relatively stable block that is dissected by relatively few faults consisting of the potentially active La Nacion Fault Zone and the active Rose Canyon Fault Zone. The Peninsular Ranges Province is also dissected by the Elsinore Fault Zone that is associated with and sub-parallel to the San Andreas Fault Zone, which is the plate boundary between the Pacific and North American Plates. The site is located within the western portion of the coastal plain geologic province roughly 1,000 feet from Buena Vista Lagoon and 2,000 feet from the Pacific Ocean. The site is located on a near flat lying marine terrace designated as Pleistocene-age Old Paralic Deposits that deposited soils at a near shore environment. The Santiago Formation is present below the terrace deposits that was deposited as a marine sandstone during the Eocene-age. The site has geologically remained unchanged since deposition of the Old Paralic Deposits. 4. SOIL AND GEOLOGIC CONDITIONS We encountered one surficial soil (consisting of undocumented fill) and two geologic formations ( consisting of Old Paralic Deposits and the Santiago Formation) during our field investigation. The occurrence, distribution and description of each unit encountered are shown on the Geologic Map, Figure 2 and the boring logs in Appendix A. The surficial soils and geologic units are described herein in order of increasing age. Project No. 02245-52-0 l - 2 -April 8, 2019 4.1 Undocumented Fill (Qudf) We encountered fill to depths ranging from about 1 to 3 feet from existing grade in the exploratory borings. The fill is likely associated with the previous grading operations performed during the original development of the property. The fill is generally composed of loose to medium dense, silty sand and sandy clay. Based on the laboratory test results, the clayey portion of the fill material at the location tested possesses a "high" expansion potential (expansion index of 91 to 130). The undocumented fill is not considered suitable for additional fill or structural loads. Remedial grading of the undocumented fill will be required as discussed herein. 4.2 Old Paralic Deposits (Qop) We encountered late to middle Pleistocene-age Old Paralic Deposits underlying the undocumented fill to depths varying from approximately 14 to 19 feet below existing grades. The Old Paralic Deposits generally consists of medium dense to very dense, silty to clayey sandstone and stiff to hard, sandy claystone. The Old Paralic Deposits are considered suitable to support additional loads from fill and the planned development. 4.3 Santiago Formation (Tsa) We encountered middle Eocene-age Santiago Formation underlying the Old Paralic Deposits at depths ranging from 14 to 19 feet (elevations of about 26 to 30 feet MSL). The Santiago Formation encountered generally consists of very dense, silty to clayey sandstone and very stiff to hard, sandy claystone. We do not expect Santiago Formation will be encountered during construction unless subterranean levels or deep underground utilities exceeding approximately 15 feet in depth are proposed. The Santiago Formation is considered suitable to support additional loads from fill and the planned development. 5. GROUNDWATER We encountered perched groundwater in Borings B-1 · through B-4 in the Old Paralic Deposits at depths ranging from approximately 7½ to 11 ½ feet below the existing ground surface (approximate elevations ranging from approximately 32½ to 37½ feet MSL). Perched groundwater should be expected if subterranean levels are proposed and in excavations for deeper utilities. It is not uncommon for groundwater or seepage conditions to develop where none previously existed. Groundwater elevations are dependent on s~asonal precipitation, irrigation, and land use, among other factors, and vary as a result. Proper surface drainage will be important to future performance of the project. Project No. 02245-52-01 - 3 -April 8, 2019 6. GEOLOGIC HAZARDS 6.1 Faulting and Seismicity A review of the referenced geologic materials and our knowledge of the general area indicate that the site is not underlain by active, potentially active or inactive faults. An active fault is defined by the California Geological Survey (CGS) as a fault showing evidence for activity within the last 11,000 years. The site is not located within a State of California Earthquake Fault Zone. According to the computer program EZ-FRISK (Version 7 .65), 10 known active faults are located within a search radius of 50 miles from the property. We used the 2008 USGS fault database that provides several models and combinations of fault data to evaluate the fault information. Based on this database, the nearest known active faults are the Newport-Inglewood/Rose Canyon Fault system, located approximately 5 miles west of the site and is the dominant source of potential ground motion. Earthquakes that might occur on this fault system or other faults within the southern California and northern Baja California area are potential generators of significant ground motion at the site. The estimated deterministic maximum earthquake magnitude and peak ground acceleration for the Newport- Inglewood Fault are 7.5 and 0.40g, respectively. The estimated deterministic maximum earthquake magnitude and peak ground acceleration for the Rose Canyon Fault are 6.9 and 0.32g, respectively. Table 6.1.1 lists the estimated maximum earthquake magnitude and peak ground acceleration for these and other faults in relationship to the site location. We used acceleration attenuation relationships developed by Boore-Atkinson (2008) NGA USGS2008, Campbell-Bozorgnia (2008) NGA USGS, and Chiou-Youngs (2007) NGA USGS2008 acceleration-attenuation relationships in our analysis. TABLE 6.1.1 DETERMINISTIC SPECTRA SITE PARAMETERS Maximum Peak Ground Acceleration Approximate Earthquake Fault Name Distance from Boore-Campbell-Chiou- Site (miles) Magnitude Atkinson Bozorgnia Youngs (Mw) 2008 (g) 2008 (g) 2007 (g) Newport-Inglewood 5 7.5 0.33 0.33 0.40 Rose Canyon 5 6.9 0.27 0.29 0.32 Coronado Bank 21 7.4 0.15 0.11 0.13 Palos Verdes Connected 21 7.7 0.17 0.12 0.15 Elsinore 23 7.9 0.26 0.21 0.29 Palos Verdes 34 7.3 0.10 0.07 0.08 San Joaquin Hills 36 7.1 0.09 0.09 0.08 Earthquake Valley 44 6.8 0.06 0.05 0.04 Chino 47 6.8 0.06 0.05 0.04 San Jacinto 47 7.9 0.10 0.07 0.09 Project No. 02245-52-0 l -4-April 8, 2019 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 mappable Quaternary fault is proportional to the faults slip rate. The program accounts for fault rupture length as a function of earthquake magnitude, and site acceleration estimates are made using the earthquake magnitude and distance from the site to the rupture zone. The program also accounts for uncertainty in each of following: ( 1) earthquake . magnitude, (2) 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 USGS 2008, Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2007) NGA USGS 2008 in our analysis in the analysis. Table 6.1.2 presents the probabilistic seismic hazard parameters including acceleration-attenuation relationships and the probability of exceedence. TABLE 6.1.2 PROBABILISTIC SEISMIC HAZARD PARAMETERS Peak Ground Acceleration Probability of Exceedence Boore-Atkinson Campbell-Bozorgnia Chiou-Youngs. 2008 (g) 2008 (g) 2007 (g) 2% in a 50 Year Period 0.45 0.47 0.52 5% in a 50 Year Period 0.33 0.33 0.36 l 0% in a 50 Year Period 0.24 0.24 0.25 While listing peak accelerations is useful for comparison of potential effects of fault activity in a region, other considerations are impor:tant in seismic design, including the frequency and duration of motion and the soil conditions underlying the site. Seismic design of the structures should be evaluated in accordance with the 2016 California Building Code (CBC) or other applicable guidelines. It is our opinion the site could be subjected to moderate to severe ground shaking in the event of an earthquake along any of the faults listed on Table 6.1.1 or other faults in the southern California/ northern Baja California region. We do not consider the site to po·ssess a greater risk than that of the surrounding developments. 6.2 Ground Rupture Ground surface rupture occurs when movement along a fault is sufficient to cause a gap or rupture where the upper edge of the fault zone intersects that earth surface. Th; potential for ground rupture is considered to be very low due to the absence of active or potentially active faults at the subject site. Project No. G2245-52-01 -5 -April 8, 2019 6.3 Liquefaction Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soils are cohesionless or silt/clay with low plasticity, groundwater is encountered within 50 feet of the surface, and soil densities are less than about 70 percent of the maximum dry densities. If the four previous criteria are met, a seismic event could result in a rapid pore water pressure increase from the earthquake-generated ground accelerations. Due to the dense to very dense nature and age of the Old Paralic Deposits and Santiago Formation, liquefaction potential for the site is considered very low. 6.4 Seiches and Tsunamis Seiches are caused by the movement of an inland body of water due to the movement from seismic forces. The site is not located near an inland body of water. Therefore, the risk of a seiche from flooding within the river valley is considered low. A tsunami is a series of long-period waves generated in the ocean by a sudden displacement of large volumes of water. Causes of tsunamis include underwater earthquakes, volcanic eruptions, or offshore slope failures. The site is located approximately 2,000 feet from the Pacific Ocean and 1,000 feet from Buena Vista Lagoon at an elevation of at least approximately 40 feet above Mean Sea Level. Therefore, the risk of tsunamis affecting the site is negligible. 6.5 Landslides Based on the generally flat topography of the site, it is our opinion that landslides are not present at the property or at a lo~ation that could impact the subject site. Project No. 02245-52-0 I - 6 -April 8, 2019 7. CONCLUSIONS AND RECOMMENDATIONS 7.1 General 7 .1.1 From a geotechnical engineering standpoint, it is our opinion that the site is suitable for construction of the proposed new residential development provided the recommendations presented herein are implemented in design and construction of the project. 7 .1.2 The site is located approximately 5 miles from the nearest active fault. Based on our background research, it is our opinion active, potentially active, or inactive faults do not extend across the site. Risks associated with seismic activity consist of the potential for moderate to strong seismic shaking. 7 .1.3 Our field investigation indicates the site is underlain by undocumented fill overlying Old Paralic Deposits and the Santiago Formation. The thickness of the undocumented fill encountered at the site during the investigation ranges from approximately 1 to 3 feet. The undocumented fill is not considered suitable for the support of additional fill and/or settlement-sensitive building structures in its current state and will require remedial grading. The Old Paralic Deposits and Santiago Formation are considered suitable for the support of compacted fill and settlement-sensitive structures. 7 .1.4 The planned structures can be supported on a shallow foundation system embedded into new compacted fill or the Old Paralic Deposits. We expect the shallow foundation system will be supported in properly compacted fill. 7.1.5 We encountered a variable perched groundwater condition within the Old Paralic Deposits at depths ranging from approximately 7½ to 11 ½ feet below the existing ground surface (approximate elevations ranging from approximately 32½ to 37½ feet MSL) in Borings B-1 through B-4. Perched groundwater and seepage should be expected during construction if subterranean levels or deep utilities are planned below a depth of about 7 feet. In addition, saturated soil should be expected at depths as shallow as 3 feet. 7 .1.6 Based on our review of the project plans, we opine the planned development can be constructed in accordance with our recommendations provided herein. We do not expect the planned development will destabilize or result in settlement of adjacent properties or impact public right-a-ways. 7 .1. 7 Proper drainage should be maintained in order to preserve the engineering properties of the fill in the graded pad areas subsequent to the grading operations. Project No. 02245-52-0 I - 7 -April 8, 2019 7 .1.8 Final grading or foundation plans have not been provided for our review. Geocon Incorporated should review the plans prior to the submittal to regulatory agencies for approval. Additional analyses may be required once the plans have been provided. 7 .2 Excavation and Soil Characteristics 7 .2.1 Excavation of the undocumented fill and Old Paralic Deposits should be possible with moderate to heavy effort using conventional heavy-duty equipment. Excavation of the Santiago Formation, if encountered, should generally be possible with heavy to very heavy effort using conventional, heavy-duty equipment during grading and trenching operations. Some soil may be saturated and require drying before proper placement and compaction. 7 .2.2 The soil encountered in the field investigation is considered to be "expansive" ( expansion index [EI] of greater than 20) as defined by 2016 California Building Code (CBC) Section 1803.5.3. Table 7 .2.1 presents soil classifications based on the expansion index., We expect a majority of the soil encountered possess a "very low" to "high" expansion potential (EI of 130 or less) in accordance with ASTM D 4829. TABLE 7.2.1 EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (El) ASTMD4829 2016 CBC Expansion Classification Expansion Classification 0-20 Very Low Non-Expansive 21-50 Low 51 -90 Medium 91 -130 High Expansive Greater Than 130 Very High 7.2.3 We performed a laboratory test on sample of the site materials to evaluate the percentage of water-soluble sulfate content. Appendix B presents results of the laboratory water-soluble sulfate content test. The test result indicates the on-site materials at the location tested possesses "S 1" sulfate exposure to concrete structures as · defined by 2016 CBC Section 1904 and ACI 318-14 Chapter 19. Table 7.2.2 presents a summary of concrete requirements set forth by 2016 CBC Section 1904 and ACI 318. The presence of water- soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from the site could yield different concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. Project No. G2245-52-0 l - 8 -April 8, 2019 Exposure Class so Sl S2 S3 TABLE 7.2.2 REQUIREMENTS FOR CONCRETE EXPOSED TO SULFATE-CONTAINING SOLUTIONS Water-Soluble ,, Maximum Sulfate (SO4) Cement Type Water to (ASTMC 150) Cement Ratio Percent by Weight by Weight1 SO4<0.10 No Type n/a Restriction 0. lO<SO4<0.20 II 0.50 0.20::;SO4::;2.00 V 0.45 SO4>2.00 V+Pozzolan or Slag 0.45 1 Maximum water to cement ratio limits do not apply to lightweight concrete Minimum Compressive Strength (psi) 2,500 4,000 4,500 4,500 7.2.4 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, further evaluation by a corrosion engineer may be performed if improvements susceptible to corrosion are planned. 7.3 Seismic Design Criteria 7.3.1 We used the Structural Engineers Association of California (SEAOC) and Office of Statewide Health Planning and Development (OSHPD) web application Seismic Design Maps (https://seismicmaps.org/) to evaluate site-specific seismic design parameters in accordance with the 2016 CBC/ASCE 7-10. Table 7.3.1 summarizes site-specific design criteria obtained from the 2016 California Building Code (CBC; Based on the 2015 International Building Code [IBC] and ASCE 7-10), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The short spectral response uses a period of 0.2 second. The building structure and improvements as currently proposed should be designed using a Site Class C in accordance with ASCE 7-10 Section 20.3.1. We evaluated the Site Class based on the discussion in Section 1613.3.2 of the 2016 CBC and Table 20.3-1 of ASCE 7-10 using blow count data presented on the boring logs in Appendix A and the unconfined compressive strength results of the samples collected during the investigation presented in Appendix B. The values presented in Table 7.3.1 are for the risk-targeted maximum considered earthquake (MCER). Project No. 02245-52-0 I - 9 -April 8, 2019 TABLE 7.3.1 2016 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2016 CBC Reference Site Class C Section 1613.3.2 • MCER Ground Motion Spectral 1.153g Figure 1613.3.1(1) Response Acceleration -Class B (short), Ss MCER Ground Motion Spectral 0.442g Figure 1613.3.1(2) Response Acceleration -Class B ( 1 sec), S 1 Site Coefficient, FA 1.000 Table 1613.3.3(1) Site Coefficient, Fv 1.358 Table 1613.3.3(2) Site Class Modified MCER 1.153g Section 1613.3.3 (Eqn 16-37) Spectral Response Acceleration (short), SMs Site Class Modified MCER 0.600g Section 1613.3.3 (Eqn 16-38) Spectral Response Acceleration (1 sec), SM1 5% Damped Design 0.769g Section 1613.3.4 (Eqn 16-39) Spectral Response Acceleration (short), Sos 5% Damped Design 0.400g Section 1613.3.4 (Eqn 16-40) Spectral Response Acceleration (1 sec), SDI 7.3.2 Table 7.3.2 presents additional seismic design parameters for projects located in Seismic Design Categories of D through F in accordance with ASCE 7-10 for the mapped maximum considered geometric mean (MCEG). The project structural engineer should evaluate the Risk Category and Seismic Design Category for the planned project. TABLE 7.3.2 2016 CBC SITE ACCELERATION PARAMETERS Parameter Value ASCE 7-10 Reference Site Class C Section 1613.3.2 MappedMCEa Peak Ground Acceleration, PGA 0.457g Figure 22-7 Site Coefficient, FPGA 1.000 Table 11.8-1 Site Class Modified MCEa 0.457g Section 11.8.3 (Eqn 11.8-1) Peak Ground Acceleration, PGAM 7.3.3 Conformance to the criteria in Tables 7.3.1 and 7.3.2 for seismic design does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if a large earthquake occurs. The primary goal of seismic design is to protect life, not to avoid all damage, since such design may be economically prohibitive. Project No. 02245-52-0 l -10 -April 8, 2019 7.4 Temporary Excavations 7.4.1 The recommendations included herein are provided for stable temporary excavations. It is the responsibility of the contractor to provide a safe excavation during the construction of the proposed project. 7.4.2 Temporary excavations should be made in conformance with OSHA requirements. The undocumented fill should be considered a Type C soil, properly compacteq fill and competent Old Paralic Deposits can be considered a Type B soil (Type C soil if seepage or groundwater is encountered), and competent Santiago Formation (without weak planes) can be considered a Type A soil (Type B soil if seepage or groundwater is encountered) in accordance with OSHA requirements. In general, special shoring requirements will not be necessary if temporary excavations will be less than 4 feet in height. Temporary excavations greater than 4 feet in height, however, should be sloped back at an appropriate inclination. These excavations should not be allowed to become saturated or to dry out. Surcharge loads should not be permitted to a distance equal to the height of the excavation from the top of the excavation. The top of the excavation should be a minimum of 15 feet from the edge of existing improvements. Excavations steeper than those recommended or closer than 15 feet from an existing surface improvement should be shored in accordance with applicable OSHA codes and regulations. 7.5 Grading 7.5.1 Grading should be performed in accordance with the recommendations provided in this report, the Recommended Grading Specifications contained in Appendix D and the City of Carlsbad Grading Ordinance. 7.5.2 Prior to commencing grading, a pre-construction conference should be held at the site with the owner/developer, city inspector, grading contractor, civil engineer, and geotechnical engineer in attendance. Special soil handling requirements can be discussed at that time. 7.5.3 Grading of the site should commence with the demolition of existing structures, improvements, vegetation and deleterious debris from the area to be graded. Deleterious debris and vegetation should be exported from the site and should not be mixed with the fill. Existing underground improvements and foundations including old septic systems or cisterns within the proposed development area should be removed and the resulting depressions properly backfilled in accordance with the procedures described herein. 7.5.4 The undocumented fill should be removed and replaced with properly compacted fill within the proposed development area. In addition, the building pad should be excavated such that Project No. G2245-52-0 I -11 -April 8, 2019 at least 3 feet of compacted fill exists below the planned structure. The undercuts should extend at least 10 feet outside of the planned building envelope, where possible. 7.5.5 It appears biofiltration basins are planned adjacent to the proposed structures. The removals for the areas of the structures adjacent to the storm water devices should be extended to at least 2 feet below the proposed foundations so the structure is supported on compacted fill. 7.5.6 The site should then be brought to final subgrade elevations with fill compacted in layers, where necessary. In general, soil native to the site is suitable for use as new fill if relatively free from vegetation, debris and other deleterious material. Layers of fill should be about 6 to 8 inches in loose thickness and no thicker than will allow for adequate bonding and compaction. Fill, including backfill and scarified ground surfaces, should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content, as determined in accordance with ASTM Test Procedure D 1557. Fill materials placed below optimum moisture content may require additional moisture conditioning prior to placing additional fill. The upper 12 inches of subgrade soil underlying pavement should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content shortly before paving operations. 7.5.7 Import fill soil (if necessary) should consist of granular materials with a "very low" to "medium" expansion potential (El of 90 or less) free of deleterious material and stones larger than 3 inches and should be compacted as recommended herein. Geocon Incorporated should be notified of the import soil source and should perform laboratory testing of import soil prior to its arrival at the site to determine its suitability as fill material. 7 .6 Shallow Foundations 7 .6.1 The proposed structures can be supported on a shallow foundation system bearing in compacted fill or formation materials. Foundations for the structure should consist of continuous strip footings and/or isolated spread footings. Continuous footings should be at least 12 inches wide and extend at least 24 inches below lowest adjacent pad grade. Isolated spread footings should have a minimum width of 2 feet and should also extend at least 24 inches below lowest adjacent pad grade. Figure 3 presents a wall/column footing dimension detail. 7.6.2 It appears biofiltration basins are planned adjacent to the proposed structures. The foundation should be deepened at least I foot below the adjacent structures. The foundation deepening can be removed if the basin devices are designed to incorporate the structural Project No. 02245-52-01 -12 -April 8, 2019 load of the planned structures. The project structural engineer should evaluate if the f<;mndations adjacent to the basins should be designed as retaining walls. 7.6.3 Steel reinforcement for continuous footings should consist of at least four No. 5 steel reinforcing bars placed horizontally in the footings, two near the top and two near the bottom. Steel reinforcement for the spread footings should be designed by the project structural engineer. 7 .6.4 The recommendations presenteq herein are based on soil characteristics only (EI of 130 or less) and are not intended to replace steel reinforcement required for structural considerations. 7.6.5 We expect foundations will be founded in properly compacted fill or Old Paralic Deposits. Foundations may be designed for an allowable soil bearing pressure of 2,000 and 4,000 pounds per square foot (psf) ( dead plus live load) for footings founded in compacted fill and Old Paralic Deposits, respectively. If a bearing value to support the structure within formational materials is contemplated, then the depth of the footing will likely need to be extended at least 3 feet below existing grades. This soil bearing pressure may be increased by 500 psf for each additional foot of foundation width and depth, respectively, up to a maximum allowable soil pressure of 4,000 and 6,000 psf in compacted fill and Old Paralic Deposits, respectively. The values presented herein are for dead plus live loads and may be increased by one-third when considering transient loads due to wind or seismic forces. 7 .6.6 Overexcavation of the footings and replacement with slurry can be performed in areas where the formational materials are not encountered at the bottom of the footing excavations if the foundations will be extended to the formational materials. Minimum two-sack slurry can be placed in the excavations for the conventional foundations to the bottom of proposed footing elevation. 7.6.7 We estimate the total and differential settlements under the imposed allowable loads to be about 1 inch based on a 6-foot square footing bearing in compacted fill or Old Paralic , Deposits. 7.6.8 As an alternative to the conventional foundation recommendations, consideration should be given to the use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The 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) DCl0.5 as required by the 2016 California Building Code (CBC Section 1808.6.2). Although this procedure was developed for expansive soil conditions, we \ Project No. 02245-52-01 -13 -April 8, 2019 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 7.6. The parameters presented in Table 7.6 are based on the guidelines presented in the PTI, DC 10.5 design manual. TABLE 7.6 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS Post-Tensioning Institute (PTI) Value DCl0.5 Design Parameters Thomthwaite 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 7.6.9 If the structural engineer proposes a post-tensioned foundation design method other than the PTI DCl0.5: 7.6.10 7.6.11 • The criteria presented in Table 7.6 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. 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. The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. If a post-tensioned mat foundation system is planned, the slab should possess a thickened edge with a minimum width of 12 inches and extend below the clean sand or crushed rock layer. Project No. G2245-52-01 -14 -April 8, 20 I 9 7.6.12 7.6.13 7.6.14 7.6.15 During the construction of the post-tension foundation system, the concrete should be placed monolithically. Under no circumstances should cold joints form between the footings/grade beams a~d the slab during the construction of the post-tension foundation system. We should observe the foundatioil excavations prior to the placement of reinforcing steel and concrete to check that the exposed soil conditions are similar to those expected and that they have been extended to the appropriate bearing strata. If unexpected soil conditions are encountered, foundation modifications may be required. Special subgrade presaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisturized to maintain a moist condition as would be expected in any such concrete placement. Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. 7.7 Concrete Slabs-On-Grade 7. 7 .1 Concrete floor slabs should possess a thickness of at least 5 inches and reinforced with a minimum of No. 4 steel reinforcing bars at 18 inches on center in both horizontal directions. The structural engineer should design the steel required for the planned loading conditions. 7. 7 .2 Slabs that may receive moisture-sensitive floor coverings or may be used to store moisture- • sensitive materials should be underlain by a vapor retarder. The vapor retarder design should be consistent with the guidelines presented in the American Concrete Institute's (ACI) Guide for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R- 06). In addition, the membrane should be installed in accordance with manufacturer's recommendations and ASTM requirements and installed in a manner that prevents puncture. The vapor retarder used should be specified by the project architect or developer based on the type of floor covering that will be installed and if the structure will possess a humidity controlled environment. 7.7.3 The bedding sand thickness should be determined by the project foundation engineer, architect, and/or developer. It is common to have 3 to 4 inches of sand in the southern California region. However, we should be contacted to provide recommendations if the ' bedding sand is thicker than 6 inches. 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 Project No. 02245-52-0 I -15 -April 8, 2019 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 recommendations presented on the foundation plans. 7.7.4 Concrete slabs should be provided with adequate construction joints and/or expansion joints to control unsightly shrinkage cracking. The design of joints should consider criteria of the American Concrete Institute when establishing crack-control spacing. Additional steel reinforcing, concrete admixtures and/or closer crack control joint spacing should be considered where concrete-exposed concrete finished floors are planned. 7. 7.5 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. 7.7.6 The foundation and 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 expected loads. 7. 7. 7 The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soil (if present), differential settlement of existing soil or soil with varying thicknesses. However, even' with· the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab comers occur. 7.8 Concrete Flatwork 7.8.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in accordance with the recommendations herein. Slab panels should be a minimum of 4 inches thick and, when in excess of 8 feet square, should be reinforced with 4 x 4 -W4.0/W4.0 ( 4 x 4 -4/4) welded wire mesh or No. 4 reinforcing bars spaced 18 inches on center in each direction to reduce the potential for cracking. In addition, concrete flatwork should be provided with crack control joints to reduce and/or control shrinkage cracking. Crack control spacing should be determined by the project structural engineer based upon the slab thickness and intended usage. Criteria of the American Concrete Institute (ACI) should be taken into consideration when establishing crack.control spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted in accordance with criteria Project No. 02245-52-01 -16 -April 8, 2019 presented in the grading section prior to concrete placement. Subgrade soil should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM D 1557 prior to placing concrete. 7.8.2 Even with the incorporation of the recommendations within this report, the exterior concrete flatwork has a likelihood of experiencing some movement due to swelling or settlement; therefore, the steel reinforcement should overlap continuously in flatwork to reduce the potential for vertical offsets within flatwork. Additionally, flatwork should be structurally connected to the curbs, where possible, to reduce the potential for offsets between the curbs and the flatwork. It is generally not economical to mitigate liquefaction for flatwork. Therefore, some repairs to flatwork will likely be required following a liquefaction event. 7.8.3 Where exterior flatwork abuts structures at entrant or exit points, the exterior slab should be dowelled into the structure's foundation stemwall. This recommendation is intended to reduce the potential for differential elevations that could result from differential settlement or minor heave of the flatwork. Dowelling details should be designed. by the project structural engineer. 7.8.4 The recommendations presented herein are intended to reduce the potential for cracking as a result of differential movement. However, even with the incorporation of the recommendations presented herein, concrete will still crack. The occurrence of concrete shrinkage cracks is independent of the soil supporting characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, the use of crack control joints and proper concrete placement and curing. Crack control joints should be spaced at intervals no greater than 12 feet. Literature provided by the Portland Concrete Association (PCA) and American Concrete Institute (ACI) present recommendations for proper concrete mix, construction, and curing practices, and should be incorporated into project construction. 7.8.5 We understand some of the flatwork may consist of permeable pavement/pavers. We recommend a drain be installed below permeable flatwork and connected at an appropriate outlet. If the drain is not installed, water from other sources ( e.g. rooftops and landscaping) should not be directed to the flatwork such that the only water experienced is from rain. The pervious flatwork should not be installed within 5 feet of the proposed structures, where possible, or a liner should be installed with an appropriate drainage system. Project No. G2245-52-01 -17 -April 8, 2019 7 .9 Retaining Walls 7 .9. l Retaining walls not restrained at the top and having a level backfill surface should be designed for an active soil pressure equivalent to the pressure exerted by a fluid density of 40 pounds per cubic foot (pct). Where the backfill will be inclined at 2: l (horizontal to vertical), we recommend an active soil pressure of 55 pcf. Soil with an expansion index (EI) of greater than 90 should not be used as backfill material behind retaining walls. 7.9.2 Retaining walls should be designed to ensure stability against overturning sliding, excessive foundation pressure. Where a keyway is extended below the wall base with the intent to engage passive pressure and enhance sliding stability, it is not necessary to consider active pressure on the keyway. 7.9.3 Unrestrained walls are those 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. Where walls are restrained from movement at the top (at-rest condition), an additional uniform pressure of 7H psf should be added to the active soil pressure for walls 8 feet or less. For walls greater than 8 feet tall, an additional uniform pressure of 13H psf should be applied to the wall starting at 8 feet from the top of the wall. 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. 7.9.4 The structural engineer should determine the Seismic Design Category for the project in accordance with Section 1613.3.5 of the 2016 CBC or Section 11.6 of ASCE 7-10. For structures assigned to Seismic Design Category of D, E, or F, retaining walls that support more than 6 feet of backfill should be designed with seismic lateral pressure in accordance with Section 1803.5.12 of the 2016 CBC. The seismic load is dependent on the retained height where H is the height of the wall, in feet, and the calculated loads result in pounds per square foot (psf) exerted at the base of the wall and zero at the top of the wall. A seismic load of 17H should be used for design. We used the peak ground acceleration adjusted for Site Class effects, PGAM, of 0.457g calculated from ASCE 7-10 Section 11.8.3 and applied a pseudo-static coefficient of 0.3. Figure 4 presents a retaining wall loading diagram. 7 .9 .5 The retaining walls may be designed using either the active and restrained (at-rest) loading condition or the active and seismic loading condition as suggested by the structural engineer. Typically, it appears the design of the restrained condition for retaining wall loading may be adequate for the seismic design of the retaining walls. However, the active earth pressure combined with the seismic design load should be reviewed and also considered in the design of the retaining walls. Project No. G2245-52-0 l -18 -April 8, 2019 7.9.6 Drainage openings through the base of the wall (weep holes) should not be used where the seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of the wall. The recommendations herein assume a properly compacted granular (EI of 90 or less) free-draining baclifill material with no hydrostatic forces or imposed surcharge load. Figure 5 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. 7.9.7 In general, wall foundations having a minimum depth and width of 1 foot may be designed for an allowable soil bearing pressure of 2,000 psf. The allowable soil bearing pressure may be increased by an additional 300 psf for each additional foot of depth and width, to a maximum allowable bearing capacity of 3,000 psf. The proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable soil bearing pressure. Therefore, retaining wall foundations should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. 7.9.8 The recommendations presented herein are generally applicable to the design of rigid concrete or masonry retaining walls. In the event that other types of walls (such as mechanically stabilized earth [MSE] walls, soil nail walls, or soldier pile walls) are planned, Geocon Incorporated should be consulted for additional recommendations. 7.9.9 Unrestrained walls will move laterally when backfilled and loading is applied. The amount of lateral deflection is dependent on the wall height, the type of soil used for backfill, and loads acting on the wall. The retaining walls and improvements above the retaining walls should be designed to incorporate an appropriate amount of lateral deflection as determined by the structural engineer. 7.9.10 Soil contemplated for use as retaining wall backfill, inc~uding 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. Project No. 02245-52-0 l -19 -April 8, 2019 7.10 7.10.1 7.10.2 7.10.3 7.11 7.11.1 Lateral Loading To resist lateral loads, a passive pressure exerted by an equivalent fluid density of 300 pounds per cubic foot (pct) should be used for the design of footings or shear keys. The allowable passive pressure assumes a horizontal surface extending at least 5 feet, or three times the surface generating the passive pressure, whichever is greater. The upper 12 inches of material in areas not protected by floor slabs or pavement should not be included in design for passive resistance. If friction is to be used to resist lateral loads, an allowable coefficient of friction between soil and concrete of 0.3 should be used for design. The friction coefficient may be reduced depending on the vapor barrier or waterproofing material used for construction in I accordance with the manufacturer's recommendations (normally about 0.2 to 0.25). The passive and frictional resistant loads can be combined for design purposes. The lateral passive pressures may be increased by one-third when considering transient loads due to wind or seismic forces. Preliminary Pavement Recommendations We calculated the flexible pavement sections in general conformance with the Ca/trans Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) using an estimated Traffic Index (TI) of 5.0, 5.5, 6.0, and 7.0 for parking stalls, driveways, medium truck traffic areas, and heavy truck and fire truck traffic areas, respectively. The project civil engineer and owner should review the pavement designations to determine appropriate locations for pavement thickness .. The final pavement sections for the pavement should be based on the R-Value of the subgrade soil encountered at final subgrade elevation. We have assumed an R-Value of 5 and 78 for the subgrade soil and base materials, respectively, for the purposes of thi_s preliminary analysis. Table 7.11.1 presents the preliminary flexible pavement sections. Project No. 02245-52-0 I -20 -April 8, 20 l 9 7.11.2 7.11.3 7.11.4 7.11.5 TABLE 7.11.1 PRELIMINARY FLEXIBLE PAVEMENT SECTION Assumed Assumed Asphalt Class 2 Location -Traffic Subgrade Concrete Aggregate Index R-Value (inches) Base (inches) Parking stalls for automobiles 5.0 5 3 10 and light-duty vehicles Driveways for automobiles 5.5 5 3 12 and light-duty vehicles Medium truck traffic areas 6.0 5 3.5 13 Driveways for heavy truck and fire truck traffic 7.0 5 4 16 Prior to placing base materials, the upper 12 inches of the subgrade soil should be scarified, moisture conditioned as necessary and recompacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content as determined by ASTM D 1557. Similarly, the base material should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Asphalt concrete should be compacted to a density of at least 95 percent of the laboratory Hveem density in accordance with ASTM D 2726. Base materials should conform to Section 26-1.028 of the Standard Specifications for The State of California Department of Transportation (Ca/trans) with a ¾-inch maximum size aggregate. The asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public Works Construction (Greenbook). The base thickness can be reduced if a reinforcement geogrid is used during the installation of the pavement. Geocon should be contact for additional recommendations, if required. A rigid Portland cement concrete (PCC) pavement section should be placed in driveway entrance aprons and trash bin loading 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-08 Guide for Design and Construction of Concrete Parking Lots using the parameters presented in Table 7 .11.2. Project No. 02245-52-0 l -21 -April 8, 2019 TABLE 7.11.2 RIGID PAVEMENT DESIGN PARAMETERS Design Parameter Design Value Modulus of subgrade reaction, k 50 pci Modulus of rupture for concrete, MR 500 psi Traffic Category, TC AandC Average daily truck traffic, ADTT 10 and 100 7 .11.6 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 Parking Stalls (TC=A) 6.0 Heavy Truck and Fire Lane Areas (TC=C) 7.5 7 .11. 7 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 3,000 psi (pounds per square inch). 7.11.8 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, and taper back to the recommended slab thickness 4 feet behind the face of the slab ( e.g., 6-inch and 7 .5-inch- thick slabs would have an 8-and 9.5-inch-thick edge, respectively). Reinforcing steel will not be necessary within the concrete for geotechnical purposes with the possible exception of dowels at construction joints as discussed herein. 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 for the 6.0-inch and thicker slabs 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. The depth of the crack-control joints should be at least ¼ of the slab thickness when using a Project No. G2245-52-01 -22 -April 8, 2019 conventional saw, or at least 1 inch when using early-entry saws on slabs 9 inches or less in thickness, as determined by the referenced ACI report discussed in the pavement section · herein. Cuts at least ¼ inch wide are required for sealed joints, and a ¾ inch wi,de cut is commonly recommended. A narrow joint width of 1/10-to 1/8-inch wide is common for unsealed joints. 7.11.10 To provide load transfer between adjacent pavement slab sections, a butt-type construction joint should be constructed. The butt-type joint should be thickened by at least 20 percent at the edge and taper back at least 4 feet from the face of the slab. As an alternative to the butt- type construction joint, dowelling cah be used between construction joints for pavements of 7 inches or. thicker. As discussed in the referenced ACI guide, dowels should consist of smooth, I-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. In addition, tie bars should be installed at the as recommended in Section 3.8.~ of the referenced ACI guide. The structural engineer should provide other alternative recommendations for load transfer. 7 .11.11 Concrete curb/gutter should be placed on soil subgrade compacted to a dry_ density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Cross-gutters should be placed on subgrade soil compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Base materials should not be placed below the curb/gutter, cross- gutters, or sidewalk so water is not able to migrate from the adjacent parkways to the pavement sections. Where flatwork is located directly adjacent to the curb/gutter, the· concrete flatwork should be structurally connected to the curbs to help reduce the potential for offsets between the curbs and the flatwork. 7.12 7.12.1 7.12.2 Permeable Interlocking Paver Recommendations We understand that the use of permeable/pervious pavement is being considered. from a storm water management perspective. The use of permeable/pervious pavement allows potential surface run-off to be stored on-site and percolated into the underlying subgrade soil; however, the existing soil conditions are not conducive to water infiltration and relatively high infiltration rates should not be expected. We calculated the paver pavement sections in general conformance with the Ca/trans Method of Flexible Pavement Design (Highway Design Manual, Section 608.4) and the Interlocking Concrete Pavement Institute (!CPI) Tech Spec Number 18. We calculated the section based on an assumed minimum R-Value of 5 and 78 for the subgrade soil and Project No. 02245-52-01 -23 -April 8, 2019 7.12.3 7.12.4 permeable base/stone materials, respectively. We used an equivalent asphalt concrete section equal to the thickness of the pavers of approximately 3 inches in accordance with Interlocking Concrete Pavement Institute (ICPI) Tech Spec Number 4. In addition, the pavers should be installed in a pattern appropriate for vehicular traffic. The vehicular pavers should possess a minimum thickness of 3 ½ inches and overlie 1 to 1 ½ inches of bedding sand or ASTM No. 8 stone. Table 7.12.1 presents the recommended permeable paver pavement section. TABLE 7.12.1 PERMEABLE PAVER PAVEMENT SECTION Minimum Option 1 Option 2 Traffic Base and Estimated Estimated Permeable Stone Paver Location Index Reservoir Thickness Bedding Class 2 ASTMC (TI) Material (inches) Coarse Base 33 R-Value Thickness Thickness Aggrega,te (inches) (Inches) Parking stalls 2" #8 / for automobiles 5.0 78 3½ 1 to 1½ 10 4" #57 I and light-duty 7"#2 vehicles Driveways for 2" #8 / automobiles 5.5 78 3½ 1 to l½ 12 4" #57 I and light-duty 9" #2 vehicles Medium truck 2" #8 / traffic areas 6.0 78 3½ 1 to 1½ 14 4" #57 I 11" #2 Driveways for 2" #8 / heavy truck 7.0 78 3½ 1 to 1½ 18 4" #57 I traffic 16" #2 The permeable base/aggregate sections can be thickened to increase the water capacity as required by the project civil engineer. Prior to placing stone materials, the subgrade soil should be scarified, moisture conditioned as necessary, and recompacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content as determined by ASTM D 1557. The depth of compaction should be at least 12 inches. Similarly, the base materials should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content. Some compactive effort should be applied to the aggregate section, if installed. The pavers should be installed and maintained in accordance with the manufacturer's recommendations. The future owners should be made aware and responsible for the Project No. 02245-52-01 -24-April 8, 2019 7.12.5 7.12.6 7.13 7.13.1 7.13.2 maintenance program. In addition, pavers tend to shift vertically and horizontally during the life of the pavement and should be expected. The pavers normally require a concrete border ( to prevent lateral movement from traffic. The concrete border surrounding the pavers should be embedded at least 6 inches into the subgrade to reduce the potential for water migration to the adjacent landscape areas and pavement areas. The pavers should be placed tightly adjacent to each other and the spacing between the paver units should be filled with appropriate filler. In areas where permeable/pervious pavement is planned, the subgrade materials should be graded to provide positive drainage (at least 1 percent) into a subdrain and controlled drainage device. The subdrain should be placed at the bottom of the pavement section along the low point of the length of the pavement to reduce the potential for water to build up within the paving section. The proposed pervious pavement is planned between buildings and the subdrain should be located in the center of the pavement area, approximately equidistant from the existing buildings. The subdrain should be connected to an approved drainage device. The drain should consist of a 3-inch diameter perforated Schedule 40, PVC pipe and placed at the bottom of the base or aggregate materials. Water should not be allowed to infiltrate within 5 feet of the proposed structures. Impermeable liners should be installed along the sides of the pavement section to prevent water migration toward the buildings. The liner should consist of a high-density polyethylene (HDPE) or equivalent with a minimum thickness of 15 mil and strong enough to prevent puncture. The liner should be sealed at the connections in accordance with manufacturer recommendations and should be properly waterproofed at the drain connection. The side liner would not be required where the concrete cutoff wall is installed below the proposed aggregate as discussed herein. Site Drainage and Moisture Protection Adequate site drainage is critical to reduce !he 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 2016 CBC 1804.4 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. 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) Project No. 02245-52-0 l -25 -April 8, 2019 7.13.3 7.13.4 7.13.5 7.13.6 7.14 7.14.1 should be placed over the waterproofing. The project architect or civil engineer should provide detailed specifications on the plans for all waterproofing and drainage. Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks, and detected leaks should be repaired promptly. D~trimental soil movement could occur if water is allowed to infiltrate the soil for prolonged periods of time. Landscaping planters adjacent to paved areas are not recommended due to the potential for surface or irrigation water to infiltrate the pavement's subgrade and base course. Area drains to collect excess irrigation water and transmit it to drainage structures or impervious above- grade planter boxes can be used. In addition, where landscaping is planned adjacent to the pavement, construction of a cutoff wall along the edge of the pavement that extends at least 6 inches below the bottom of the base material should be considered. We understand storm water management devices are planned for the proposed development and biofiltration basins are planned adjacent to the proposed structures. Appendix D presents recommendations regarding storm water management. Liners and subdrains should be incorporated into the design and construction of the planned storm water devices. The liners should be installed on the sides and bottoms of the planned basins and should be impermeable ( e.g. High-density polyethylene, HDPE, with a thickness of about 40 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should be perforated within the liner area, installed at the base and above the liner, be at least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner should consist of solid pipe. The penetration of the liners at the subdrains should be properly waterproofed. The subdrains should be connected to a proper outlet. The devices should also be installed in accordance with the manufacturer's recommendations. Grading and Foundation Plan Review Geocon Incorporated should review the project grading and foundation plans prior to final design submittal to check if additional analyses and/or recommendations are required. Project No. 02245-52-0 I -26 -April 8, 2019 LIMITATIONS AND UNIFORMITY OF CONDITIONS 1. 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 I 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. 2. 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. 3. 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 the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. 4. 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 they be 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. Project No. 02245-52-0 l April 8, 2018 THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH, SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS NOT INTENDED FOR CLIENTS USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT OF SUCH USE OR RELIANCE BY CLIENT. VICINITY MAP GEOCON INCORPORATED GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 -297 4 PHONE 858 558-6900 -FAX 858 558-6159 t N NO SCALE 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA LR/ RA DSK/GTYPD DATE 04 -08 -2019 I PROJECT NO. G2245 -52 -01 I FIG. 1 Plotted:04/05/2019 2:21 PM I By:RUBEN AGUILAR I File Location:Y:IPROJECTSIG2245-52-01 2690 Roosevelt Street\DETAILSIG2245-52-01 VicinityMap.dwg 1--- tj ~-Ir llllWOIWlllllT V) 1--- G:J :::::;: ~ C) C) ct:: 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA I o· 20' .,,. SCAL£ 1 •• 20' (On '1x17) GEOCON LEGEND Qudf .. .uNoocuMeNTEo Fill Qop ...... OlOPA.RALICDEPOSITS(Ootted~Buried) B-Ss ..... .APPROX.LOCATIONOFBORtNG P-2@ ....... APPROX. LOCATION~ INFILTRATION TEST GEOCON GEOTECHNICAl •ENVIRONMENTAL ■ .MATERIALS 0960RAM:IERSOIIIV£ ·SANDl:GO ~ 9'2121 • 297, PK'.)f,e1,51~-f.Ui.51s»ctU9 PROJECT NO. G2245 · 52 -01 GEOLOGIC MAP ~~Reo!.oa-2010 SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI CONCRETE SLAB CONCRETE SLAB PAD GRADE ·.• .... . .. -... . ·_. .:.-·.-. _;,, .4 . Ii-------FOOTING WIDTH*------ * .... SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION NO SCALE WALL/ COLUMN FOOTING DIMENSION DETAIL GEOCON INCORPORATED GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 -297 4 PHONE 858 558-6900 -FAX 858 558-6159 LR /RA DSK/GTYPD 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA DATE 04 -08 -2019 I PROJECT NO. G2245 -52 -01 I FIG. 3 Plotted:04/05/2019 2:22PM I By:RUBEN AGUILAR I File Location:Y:\PROJECTS\G2245-52-01 2690 Roosevelt Street\OETAILS\Wall-Column Footing Dimension Detail (COLFOOT2).dwg RETAINING WALL NOTES: H (Feet) FOOTING ACTIVE PRESSURE SEISMIC (IF REQUIRED) ACTIVE PRESSURE, A (psf) EXPANSION LEVEL 2:1 SLOPING INDEX, El BACKFILL BACKFILL El :SSO 35 50 El s 90 40 55 1.. A SURCHARGE OF 2 FEET OF SOIL (250 PSF VERTICAL LOAD) SHOULD BE ADDED TO THE DESIGN OF THE WALL WHERE TRAFFIC LOADS ARE WITHIN A HORIZONTAL DISTANCE EQUAL TO ½ THE WALL HEIGHT. OTHER SURCHARGES SHOULD BE APPLIED, AS APPLICABLE. 2 ..... EXPANSION INDEX GREATER THAN 50/90 SHOULD NOT BE USED FOR WALL BACKFILL PER REPORT. 3... RETAINING WALLS SHOULD BE PROPERLY DRAINED AND WATER PROOFED. 4... THE PROJECT STRUCTURAL ENGINEER SHOULD EVALUATE THE WALLS LOADING COMBINATIONS. AT-REST/ RESTRAINED (IF REQUIRED) r i4--- 7H H :S 8' - - H >8' ::: - - - RETAIN ING WALL LOADING DIAGRAM 13H psf GEOCON INCORPORATED GEOTECH NICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 • 297 4 PHONE 858 558-6900 -FAX 858 558-6159 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA NO SCALE LR/ RA DSK/GTYPD DATE 04 -08 -2019 I PROJECT NO. G2245 -52 -01 I FIG. 4 Plotted:04/05/2019 2:22PM I By:RUBEN AGUILAR I File Location:Y:\PROJECTS\G2245-52--01 2690 Roosevelt Street\DETAILS\Retaining Wall Loading Diagram (RWLD-NoGroundwater).dwg PROPOSED GRADE WATER PROOFING PER ARCHITECT 2/3 H GROUND SURFACE RETAINING WALL 2/3 H GROUND SURFACE DRAINAGE PANEL (MIRA.DRAIN 6000 OR EQUIVALENT) 3/4" CRUSHED ROCK 12"1 ___ J/ (1 CU.FT./FT.) :~$J~v~~::f{fr:R EQUIVALENT ~~~~~~,,;--..__I _ _, FOOTING 4" DIA. SCHEDULE 40 PERFORATED PVC PIPE OR TOTAL DRAIN EXTENDED TO APPROVED OUTLET NOTE : DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING GROUND SURFACE TEMPORARYBACKCUT PER OSHA MIRAFI 140N FILTER FABRIC (OR EQUIVALENT) OPEN GRADED 1" MAX. AGGREGATE 4" DIA. PERFORATED SCHEDULE 40 PVC PIPE EXTENDED TO APPROVED OUTLET PROPOSED GRADE RETAINING WALL 2/3 H 1/ GROUND SURFACE 4" DIA. SCHEDULE 40 PERFORATED PVC PIPE OR TOTAL DRAIN EXTENDED TO APPROVED OUTLET NO SCALE TYPICAL RETAINING WALL DRAIN DETAIL GEOCON INCORPORATED GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 -297 4 PHONE 858 558-6900 -FAX 858 558-6159 LR/RA DSK/GTYPD 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA DATE 04 -08 -2019 I PROJECT NO. G2245 -52 -01 I FIG. 5 Plotted:04/05/2019 2:22PM I By:RUBEN AGUILAR I File Location:Y:IPROJECTSIG2245-52-01 2690 Roosevelt StreetlOETAILSITypical Retaining Wall Drainage Detail (RWDD7A).dwg APPENDIX APPENDIX A FIELD INVESTIGATION Fieldwork for our investigation included a subsurface exploration and soil sampling. The Geologic Map, Figure 2 presents the locations of the exploratory borings. Boring logs and an explanation of the geologic units encountered are presented in figures following the text in this appendix. We located the borings in the field using a measuring tape and existing reference points. Therefore, actual boring locations may deviate slightly. We performed a field investigation on February 1, 2018 that consisted of drilling 5 exploratory borings to a maximum depth of approximately 19 ½ feet below existing grade with an Ingersoll Rand A-300 drill rig equipped with 8-inch-diameter hollow-stem auger with Scott's Drilling Company. We obtained bulk and ring samples from the exploratory borings for laboratory testing. We obtained samples during our boring excavations using a California split-spoon sampler. The sampler is composed of steel and is driven to obtain the soil samples. The California sampler has an inside diameter of 2.5 inches and an outside diameter of 2.875 inches. Up to 18 rings are placed inside the sampler that is 2.4 inches in diameter and 1 inch in height. Ring samples at appropriate intervals were retained in moisture-tight containers and transported to the laboratory for testing. We also retained bulk samples from the borings for laboratory testing. The type of sample is noted on the exploratory boring logs. The samplers were driven 12 using the California sampler into the bottom of the excavations with the use of a Cathead hammer and the use of A rods. The sampler is connected to the A rods and driven into the bottom of the excavation using a 140-pound hammer with a 30-inch drop. Blow counts are recorded for every 6 inches the sampler is driven. The penetration resistances shown on the boring logs are shown in terms of blows per foot. The values indicated on the boring logs are the sum of the last 12 inches of the sampler if driven 18 inches. If the sampler was not driven for 18 inches, an approximate value is calculated in term of blows per foot or the final 6-inch interval is reported. These values are not to be taken as N-values, adjustments have not been applied. We estimated elevations shown on the boring logs from a topographic map. We visually examined the soil conditions encountered within the borings, classified, and logged in general accordance with the Unified Soil Classification System (USCS). Logs of the borings are presented on Figures A-1 through A-5. The logs depict the general soil and geologic conditions encountered and the depth at which we obtained the samples. Project No. 02245-52-0 I April 8, 2018 PROJECT NO. G2245-52-01 0::: BORING B 1 Zw ~ /'.: >-LL.I w ~ I-Qui-: DEPTH (!) ~ SOIL 1-zu.. u5 --:-o:::~ SAMPLE 0 ~~ui zu.. :::::> I- IN ...J LL.I • 1-Z 0 0 CLASS ELEV. (MSL.) 46' DATE COMPLETED 02-01-2018 I-CJ):§: OU (/) LL.I FEET NO. ::c: z w-o >-e:. -I- I-:::::> (USCS) ZCJ)J O z :J 0 LL.I LL.I (I) 0::: ::!E O 0::: EQUIPMENT IR A..JOO BY: L RODRIGUEZ a..O:::~ 0 u (!) MATERIAL DESCRIPTION -0 ----r-t--r Bl-I SM UNDOCUMENTED FILL (Qudf) --Ht Loose, moi st, yellowish brown, Silty, fine to medium SA D; trace gravel; -trace organics -2 - ----1·--·l -1:-- - :---.. ---r-:-:---Bl-2 Y.-:4 :;(. SC OLD PARALIC DEPOSITS (Qop) 80/1 I" 101.4 23.2 "½~•-•: 4 :;(.: .. Very dense, wet, light yellowish to grayish brown, Clayey, fine SANDSTONE --. ~:-·;; - ;t-: :;(. ,... -;:,;;:-.. : ~ Bl-3 »;f.:, -Becomes dense, wet 49 96.3 25.9 ·,:, ,... 6 -0:-{~ ~ ~:1/.;f.'.. ,... -~~:•r~ ~ *~ -8 -;: .½. •: ~ :;(-0:' --0:-{}. -~:1/.;f.'.. .!. -10 -If.).~ -Perched groundwater at 9.5 feet - Bl-4 ;.)!: -Becomes medium dense 42 113.7 16.6 --»;f.:, - ~ .:, -12 -0: :~ -~:1/.;f.'.. --f.)~ - ~/..(.: -14 -»;f.:, - ~ .:, -Grinding on cobble 0:'.~ --I ~:1/.;f.'.: - Bl-5 f).~ -Becomes very dense, saturated, trace rounded gravel 62/11.5" 101.8 24.1 -16 -~/..(.: - --»;f.:, - ~·,;, ¼': :~ ;.½ . f-18 -. ·,;f.'.· - :;(.: ~y.:~-:.; ~ . , f--Bl-6 : •t • )• :~: SANTIAGO FORMATION (Tsa) 5015" 116.0 14.8 \ Very dense, saturated, white, Silty, fine-to coarse-grained SANDSTONE I BORING TERMINATED AT 19.5 FEET Perched groundwater at 9.5 feet Figure A-1, G2245-52-01.GPJ Log of Boring B 1, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] ... STANDARD PENETRATION TEST liiiJ .. CHUNK SAMPLE ■ ... DRIVE SAMPLE (UNDISTURBED) _y ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. G2245-52-01 a:: BORING B 2 Zw~ ~ w ~ >-UJ Qui-: t- DEPTH (.'J ~ SOIL t-zu.. ci5 -:-a::~ SAMPLE 0 ci~in zu.. => t- IN ....J UJ0 1-Z 0 0 CLASS ELEV. (MSL.) 45' DATE COMPLETED 02-01-2018 t-(/) s: (/) UJ NO. z O · -t-FEET I w-o >-e:. t-=> (USCS) z (/) ....J Oz ::; 0 UJ UJ co a:: :EO a:: EQUIPMENT IR A-300 BY: L. RODRIGUEZ o..a::~ 0 u (.'J MATERIAL DESCRIPTION -0 :-r-t -y SM UNDOCUMENTED FILL (Qudf) --ltt Loose, moist, yellowish to grayish brown, Silty, fine to medium SAND; trace - organics -2 -• f ,. ·t· I•: :j•:• • SM OLD PARALIC DEPOSITS (Qop) 82-1 • ·t· ..• f. Dense, wet, light yellowish to grayish brown, Silty, fine SANDSTONE 61 105.5 20.2 - -: : :~::.: - • f ·t· -4 -\j\ - --I : :f: ~: :t•: f- 82-2 •. •j· .•• -Becomes very dense 75/11" 93.6 25.4 -6 -:-t. -:f: -\~\ --\j\ .... -8 -\~\ - ::t-*:f: - -.. ·~· .. -.• f •• •t'. 10 -: : . : l:: : ---------------------------------------------------- 82-3 I CL Very stiff, wet, gray to yellowish brown, Sandy CLA YSTONE 33 92.7 26.2 --- .Y -12 --Perched groundwater at 11 inches - ----Gravel layer -14 -f- - - 82-4 I . ·f. ,. "t. SM SANTIAGO FORMATION (Tsa) 90/10" -16 -\j\ Very dense, saturated, light gray, Silty, fine-to coarse-grained SANDSTONE - --\~\ -\j\ -18 -::fft-: I- :.r: --I ::t/f: I- 82-5 -Becomes light yellowish brown 5016" BORJNG TERMlNA TED AT 19.5 FEET Perched groundwater at 11.5 feet Figure A-2, G2245-52-01.GPJ Log of Boring B 2, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE IJ ... STANDARD PENETRATION TEST ~ ... CHUNK SAMPLE ■ ... DRIVE SAMPLE (UNDISTURBED) Y, ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. G2245-52-01 DEPTH IN FEET -0 -2 - - 6 - -- -8 - I-- 1-10 - ,_ 12 - ,-14 - -16 - -- -18 - I-- SAMPLE NO. B3-1 B3-2 B3-3 B3-4 B3-5 B3-6 >-(.? 0 ....J 0 J: 1-::::i 0:: LJ.J i SOIL Cl CLASS z :J (USCS) 0 0:: C, CL SC BORING B 3 ELEV. (MSL.) 43.5' DATE COMPLETED 02-01-2018 EQUIPMENT IR A.JOO BY: L. RODRIGUEZ MATERIAL DESCRIPTION UNDOCUMENTED FILL (Qudt) Stiff, moist, yellowish brown, Sandy CLAY; trace gravel; trace organics OLD PARALIC DEPOSrTS (Qop) Dense, wet, yellowish to grayish brown, Clayey, fine SANDSTONE I- ~ 50 103.5 48 106.9 - ___ -r--_ -Perched groundwater at 7.5 feet _ _ __ _ _ _ _ __ _ _ _ _ _ _ _,_ ___ ,_ __ _ CL Stiff, wet, gray to yellowish brown, Silty CLA YSTONE I- 19 77.0 --------------------------------------~-------SC Medium dense to dense, wet, gray to yellowish brown, Clayey, fine to medium SM SANDSTONE SANTlAGO FORMATION (Tsa) Very dense, moist, light gray to white, Silty, fi ne-to coarse-grained SANDSTONE BORING TERMINATED AT 19.5 FEET Perched groundwater at 7.5 feet - 90/10" 50/5.5" w ~ o::~ :J I-I-z (J) LJ.J -1-0 z ~o u 22.3 19.6 ---- 43.2 Figure A-3, G2245-52-01 .GPJ Log of Boring B 3, Page 1 of 1 SAMPLE SYMBOLS □ .. SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED) !i;I ... CHUNK SAMPLE ~ ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJ ECT NO. G2245-52-01 0:: >-UJ I-DEPTH C) ; SOIL SAMPLE 0 IN ...J 0 0 CLASS FEET NO. :I: z => (USCS) I-:::i 0 0:: C) 0 B4-1 SM 2 cusc B4-2 4 B4-3 \]\ SM 6 \1\ \]\ 8 \1\ ::t•*:~: . 1 .. . . . . . . . . . .. 10 B4-4 SC 12 14 B4-5 CL 16 18 B4-6 SC BORING B 4 ELEV. (MSL.) 42' DATE COMPLETED 02-01 -2018 EQUIPMENT IR A-300 BY: L. RODRIGUEZ MATERIAL DESCRIPT ION UNDOCUMENTED FrLL (Qudf) Medium dense, moist, reddish brown, Silty, fine to medium SAND; trace organics OLD PARALIC DEPOSITS (Qop) Hard/dense, damp, grayish brown, Sandy CLA YSTONE to Clayey, fine to medium SANDSTONE ---------------------------------Medium dense, damp, yellowish to grayish brown, Silty, fine to medium SANDSTONE -Perched groundwater at 8.5 feet ---------------------------------Medium dense, saturated, yellowish to grayish brown, Clayey, fine to medium SANDSTONE SANTIAGO FORMATION (Tsa) Very stiff, moist, greenish brown, Sandy CLA YSTONE Very dense/hard, moist, light yellowish brown, Clayey, fine-to medium-ined SANDSTONE to Sandy CLA YSTONE BORJNGTERMINATEDAT 19.5 FEET Perched groundwater at 8.5 feet Zw~ >-w '#. Qui-: I- 1-zu. ci5 ---:-o::- ~~en zu. => I-I-z 1-C/J ~ ~<..i (/) UJ -I-w-o >-e:. O z z (/) ...J UJ UJ co 0:: ~o a.. o::-0 u 58 122.5 11.8 30 107.2 4.9 35 111.4 18.5 41 50/6" Figure A-4, G2245-52-01 .GPJ Log of Boring B 4, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I) ... STANDARD PENETRATION TEST ~ ... CHUNK SAMPLE ■ ... DRIVE SAMPLE (UNDISTURBED) ~ ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON PROJECT NO. G2245-52-01 a::: BORING B 5 Zw -~ >-w w 'cfl. I-Qu~ DEPTH CJ ~ SOIL 1-Z U.. cii ---:-a:::- SAMPLE 0 ~;:: in zu.. ::, I- IN ...J ~c_j I-z 0 0 CLASS ELEV. (MSL.) 42' DATE COMPLETED 02-01-2018 I-(/) s: C/Jw FEET NO. I z w-o >-~ -I- I-::, (USCS) z (/) ...J oz :::i 0 WW[D a::: ::i;O a::: EQUIPMENT IR A.JOO BY: L. RODRIGUEZ c..0:::-0 u CJ MATERIAL DESCRIPTION f--0 . .-·1·-t .·1-.-•. ·J .. SM UNDOCUMENTED FILL (Qudf) f-----~ ·.-. •. ·.: .-: Medium dense, reddish brown, Silty, fine to medium SAND; trace gravel I:~· CL OLD PARALIC DEPOSITS (Qop) -2 -Stiff, wet, dark grayish brown, Sandy CLA YSTONE - --B5-I _ 39 115.8 17.6 ------~--------------------------------------------- -4 -~·:;;:-· ... SC Dense, wet, yellowish to grayish brown, Clayey, fine SANDSTONE -·y.?· f---f).~ ._ B5-2 ~).!: -Becomes very dense 77/11.5" 126.1 11.7 f--6 -:;(-0:• ._ ~1j f---~1/.;f.'.. ._ :?-:~:-~~ f--8 -~: ~ ._ ;:,z..-: :;(.;f.:, f---·,:,. ._ i-~~ -10 -~1/.;f.'.. ._ B5-3 :?-:~:-~~ -Becomes dense, coarser grained 47 114.6 18.2 ;r-:;(. ---;:,z..-: :;(-0'.' -12 -i-7-:;?,'/ - ~:½. --. ·;f.'.· -:?-:~:•~~ ;t-: : Y. -14 -.. ',,, . ·-f-1·r SM SANTIAGO FORMATION (Tsa) --\l\ Very dense, moist, light gray to white, Silty, fine-to coarse-grained - B5-4 : :~: 1: :t.; SANDSTONE 5015" -16 -• •j• -t <~: --\1\ - -18 -\l\ ~ \1\ 'Sl---:)·.J.·.c: ~ B5-5 ... -Seepage at 19 feet 5015.5" BORING TERM1NA TED AT 19 .5 FEET Figure A-5, G2245-52-01.GPJ Log of Boring B 5, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] ... STANDARD PENETRATION TEST liiiJ .. CHUNK SAMPLE ■ ... DRIVE SAMPLE (UNDISTURBED) y_ ... WATER TABLE OR SEEPAGE NOTE: THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. GEOCON APPENDIX APPENDIX B LABORATORY TESTING We performed laboratory tests in accordance with generally currently accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. We tested selected soil samples for in-place density and moisture content, maximum dry density and optimum moisture content, direct shear strength, expansion index, water-soluble sulfate content, unconfined compressive strength, gradation and consolidation. Tables B-1 through B-V and Fi~es B-1 through B-3 present the results of our laboratory tests. In addition, the in-place dpr density and moisture content test results are presented on the boring logs in Appendix A. Sample No. B3-1 Sample TABLE 8-1 SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Maximum Description (Geologic Unit) Dry Density (pct) Yellowish brown, Sandy CLAY (Qudf/Qop) 118.3 TABLE 8-11 SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS ASTM D 3080 Dry Moisture Peak Depth Geologic Density Content(%) [Ultimate1] Optimum Moisture Content (% dry wt.) 13.7 Peak [Ultimate1] Angle of Shear No. (feet) Unit (pct) Cohesion (pst) Resistance (degrees) Initial Final B3-12 0-5 Qudf/Qop 106.6 14.0 23.4 650 [650] 1 Ultimate measured at 0.2-inch deflection. 2 Remolded to a dry density of about 90 percent of the laboratory maximum density. Sample No. B3-1 , TABLE 8-111 SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D4829 Moisture Depth Geologic Content(%) Dry Expansion ASTM Density Expansion (feet) Unit Before After (pct) Index Classification Test Test 0-5 Qudf/Qop 13.5 31.4 98.5 105 High Project No. 02245-52-0 l -B-1 - 24 [19] 2016 CBC Expansion Classification Expansive April 8, 2019 TABLE B-IV SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Depth (feet) Geologic Unit Water-Soluble Sulfate Exposure Sulfate(%) Class B3-1 0-5 Qudf/Qop 0.179 S1 TABLE B-V SUMMARY OF LABORATORY UNCONFINED COMPRESSIVE STRENGTH TEST RESULTS ASTM D 1558 Hand Penetrometer Sample No. Depth (feet) Geologic Unit Reading, Unconfined Undrained Shear Compression Strength Strength (kst) (tst) Bl-2 3 Qop 4.5+ 4.5+ Bl-3 5 Qop 4.5+ 4.5+ Bl-4 10 Qop 4.5+ 4.5+ B2-1 2½ Qop 4.5+ 4.5+ B2-2 5 Qop 4.5+ 4.5+ B2-3 10 Qop 4.5+ 4.5+ B3-2 2½ Qop 4.5+ 4.5+ B3-3 5 Qop 4.5+ 4.5+ B3-4 10 Qop 2.5 2.5 B4-2 2½ Qop 4.5+ 4.5+ B4-3 5 Qop 4.5+ 4.5+ B4-4 10 Qop 4.5+ 4.5+ B4-5 15 Tsa 4.5+ 4.5+ B4-6 19 Tsa 4.5+ 4.5+ B5-1 2½ Qop 4.5+ 4.5+ B5-2 5 Qop 3.0 3.0 B5-3 10 Qop 4.5+ 4.5+ Project No. G2245-52-01 -B-2 -April 8, 2019 PROJECT NO. G2245-52-01 GRAVEL SAND COARS1: I FINE COARSE MEDIUM FINE SILT OR CLAY U. S. STANDARD SIEVE SIZE 110 16 30 50 3" 1-1,12" 3/f'," 3/8" 4 ·1· 20 40 6,0 190 290 100 I I I I i-., I I I I I 'I\_ I 90 I I II I I .. I I I I 80 I I \ I 11 I \ II I I I I I I I-70 1, I ::c (!) I I I w I I \ I ~ 60 11 II :1 >-I I ' I ID I. I I c::: I I I w 50 I II ' I z U::: I I I I-I I I z 40 I 11 w I I \ I l) c::: I I I w 30 I I I a.. I I \ I I I I 20 I I I II I ~~ I I 'N I I I ... --10 ----I I I -I I I ~.:.. 0 II I II 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS ASTMD422 SAMPLE DEPTH (ft) CLASSIFICATION NAT.WC LL PL Pl • B4-3 5.0 SM -Silty SAND Ill ... GRADATION CURVE 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA G2245-52-01.GPJ Figure B-1 GEOCON PROJECT NO. G2245-52-01 SAMPLE NO. 82-3 -6 -4 -2 -~ ' I'-, I) ", ---~ ---... ~ -.. ""' ,-.... \ ~ 1'---r-,. ~ ..,i'----"" z 2 <i: ..., . I"-\ a:: I-\ en ' ..J I'--<( (.) '\ i= 4 '. a:: w > 6 8 10 12 0.1 1 10 100 APPLIED PRESSURE (ksf) ASTM D2435 Initial Dry Density (pcf) 86.6 Initial Saturation (%) 100+ Initial Water Content (%) 36.2 Sample Saturated at (ksf) 2.0 CONSOLIDATION CURVE 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA G2245-52-01.GPJ Figure 8-2 GEOCON PROJECT NO. G2245-52-01 SAMPLE NO. 84-3 -6 -4 -2 -V -r--, ~ " ~i.... ... It....._ -::R ~ ~ z ,.__ <( 2 --..... 0::: r---. .... I-Cl) ...J ~ (..) F 4 0::: w > 6 8 10 12 0.1 1 10 100 APPLIED PRESSURE (ksf) ASTM D2435 Initial Dry Density (pcf) 107.2 Initial Saturation (%) 23.8 Initial Water Content(%) 4.9 Sample Saturated at (ksf) 2.0 CONSOLIDATION CURVE 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA G2245-52-01.GPJ Figure 8-3 GEOCON APPENDIX APPENDIXC STORM WATER MANAGEMENT INVESTIGATION We understand storm water management devices will be used in accordance with the 2016 City of Carlsbad BMP Design Manual. If not properly constructed, there is a potential for distress to improvements and properties located hydrologically down gradient or adjacent to these devices. Factors such as the amount of water to be detained, its residence time, and soil permeability have an important effect on seepage transmission and the potential adverse impacts that may occur if the storm water management features are not properly designed and constructed. We have not performed a hydrogeolo,gical study at the site. If infiltration of storm water runoff occurs, downstream properties may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other undesirable impacts as a result of water infiltration. Hydrologic Soil Group The United States Department of Agriculture (USDA), Natural Resources Conservation Services, possesses general information regarding the existing soil conditions for areas within the United States. The USDA website also provides the Hydrologic Soil Group. Table C-1 presents the descriptions of the hydrologic soil groups. If a soil is assigned to a dual hydrologic group (AID, BID, or CID), the first letter is for drained areas and the second is for undrained areas. ,In addition, the USDA website also provides an estimated saturated hydraulic conductivity for the existing soil. TABLE C-1 HYDROLOGIC SOIL GROUP DEFINITIONS Soil Group Soil Group Definition Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These A consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of B moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate , of water transmission. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils C having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These D consist chiefly of clays that have a high shrink-swell potential, soils that have a high-water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. Project No. G2245-52-01 -C-1 -April 8, 2019 The property is underlain by man-made fill and should be classified as Soil Group D. Table C-2 presents the information from the USDA website for the subject property. TABLE C-2 USDA WEB SOIL SURVEY -HYDROLOGIC SOIL GROUP Approximate ksAT of Most Map Unit Name Map Unit Percentage Hydro logic Limiting Symbol of Property Soil Group Layer (inches/hour) Marina loamy coarse sand, 2 to 9 percent slopes MIC 100 B 0.57 -1.98 In-Situ Testing The degree of soil compaction or in-situ density has a significant impact on soil permeability and infiltration. Based on our experience and other studies we performed, an increase in compaction results/ in-place density results in a general decrease in soil permeability. Based on discussions with the local regulatory agencies, the infiltration categories include full infiltration, partial infiltration and no infiltration. Table C-3 presents the definitions of the potential infiltration categories, Infiltration Category Full Infiltration Partial Infiltration No Infiltration (Infeasible) TABLE C-3 INFILTRATION CATEGORIES Field Infiltration Rate, I (Inches/Hour) I> 1.0 0.10 <I::: 1.0 I< 0.10 Factored Infiltration Rate, I (Inches/Hour) I> 0.5 0.05 <I::: 0.5 I< 0.05 The infiltration rate, percolation rates and saturated hydraulic conductivity are different and have different meanings. Percolation rates tend to overestimate infiltration rates and saturated hydraulic conductivities by a factor of 10 or more. Table C-4 describes the differences in the definitions. Project No. 02245-52-0 I -C-2 -April 8, 2019 TABLE C-4 SOIL PERMEABILITY DEFINITIONS Term Definition The observation of the flow of water through a material into the ground Infiltration Rate downward into a given soil structure under long term conditions. This is a function of layering of soil, density, pore space, discontinuities and initial moisture content. The observation of the flow of water through a material into the ground Percolation Rate downward and laterally into a given soil structure under long term conditions. This is a function of layering of soil, density, pore space, ' discontinuities and initial moisture content. The volume of water that will move in a porous medium under a Saturated Hydraulic hydraulic gradient through a unit area. This is a function of density, Conductivity (ksAT, Permeability) structure, stratification, fines content and discontinuities. It is also a function of the properties of the liquid as well as of the porous medium. The degree of soil compaction or in-situ density has a significant impact on soil permeability and infiltration. Based on our experience and other studies we performed, an increase in compaction results in a decrease in soil permeability. We performed 2 Aardvark Permeameter tests at locations shown on the attached Geologic Map, Figure 2. The test borings were 4½ inches in diameter. The results of the tests provide parameters regarding the saturated hydraulic conductivity and infiltration characteristics of on-site soil and geologic units. Table C-5 presents the results of the estimated field saturated hydraulic conductivity and estimated infiltration rates obtained from the Aardvark Permeameter tests. The field sheets are also attached herein. We did not use a factor of safety applied to the test results on the worksheet values. The designer of storm water devices should apply an appropriate factor of safety. Soil infiltration rates from in-situ tests can vary significantly from one location to another due to the heterogeneous characteristics inherent to most soil. Based on a discussion in the County of Riverside Design Handbook for Low Impact Development Best Management Practices, the infiltration rate should be considered equal to the saturated hydraulic conductivity rate. TABLE C-5 FIELD PERMEAMETER INFILTRATION TEST RESULTS Test Test Depth Geologic Field-Saturated C.4-1 Worksheet Infiltration Rate, ksat Infiltration Rate1, ksat Location (feet, below grade) Unit (inch/hour) (inch/hour) P-1 2 Qop 0.008 0.004 P-2 2 Qop 0.183 0.092 Average: 0.096 0.048 1 Using a factor of safety of 2. Project No. 02245-52-01 -C-3 -April 8, 2019 The test results indicate the approximate infiltration rates range from approximately 0.008 to 0.183 inches per hour (0.004 to 0.092 inches per hour with an applied factor of safety of 2). The average infiltration rate with an applied factor of safety of 2 is 0.048 inches per hour. Full and partial infiltration should be considered infeasible at the site because the average infiltration rate is less than 0.05 inches per hour. Groundwater Elevations We encountered perched groundwater during our investigation at depths ranging from approximately 7½ to 11 ½ feet below the existing ground surface (approximate elevations ranging from approximately 32½ to 37½ feet MSL). Therefore, infiltration is considered infeasible at the site. New or Existing Utilities Utilities are present on the existing property and within the existing adjacent Roosevelt Street. Full or partial infiltration should not be allowed in the areas of the utilities to help prevent potential damage/distress to improvements. Mitigation measures to prevent water from infiltrating the utilities consist of setbacks, installing cutoff walls around the u~ilities and installing subdrains and/or installing liners. Existing and Planned Structures Existing structures exist to the north and south and east of the site. Water should not be allowed to infiltrate in areas where it could affect the existing and neighboring properties and existing and adjacent structures, improvements and roadways. Mitigation for existing structures consist of not allowing water infiltration within a 1: 1 plane from existing foundations and extending the infiltration areas at least 10 feet below the existing foundations and into formational materials. Slopes and Other Geologic Hazards There are no slopes present or geologic hazards at the site that would preclude infiltration at the site. Storm Water Evaluation Narrative The site is underlain by approximately 1 to 3 feet of undocumented fill across the site. In our experience, fill does not possess infiltration rates appropriate with infiltration. Therefore, infiltration is considered infeasible within the undocumented fill. The formational Old Paralic Deposits underlies the undocumented as shallow as 1 to 3 feet deep and extending to approximately 14 to 19 feet below existing grade. We performed 2 infiltration tests within the Old Paralic Deposits and the results indicate an infiltration rate of less than 0.05 inches Project No. 02245-52-0 l -C-4 -April 8, 2019 per hour. Infiltration should not be allowed in soils that possess an infiltration rate less than 0.05 inches per hour; therefore, partial and full should be considered infeasible within the Old Paralic Deposits. The Santiago Formation exists below the Old Paralic Deposits. We did not perform infiltration testing within the Santiago Formation due to the depth of the formation. It would be unreasonable and costly to install storm water devices at depths exceeding approximately 15 feet at the site. We encountered perched groundwater during our investigation at depths ranging from approximately 7½ and 11 ½ feet below the existing ground surface. We expect the bottom of planned storm water infiltration devices will extend to depths of 2 feet or greater below the existing ground surface at the site, therefore, we expect the bottom of the any planned storm water devices will be within 10 feet of groundwater. Therefore, infiltration is considered infeasible at the site. Therefore, due to the characteristics of the onsite soils and the depth of the groundwater relative to the bottom of planned storm water devices, infiltration should be considered infeasible and any planned storm water device should be lined. Storm Water Management Devices Liners and subdrains should be incorporated into the design and construction of the planned storm water devices. The liners should be installed on the sides and bottoms of the planned basins and should be impermeable ( e.g. High-density polyethylene, HDPE, with a thickness of about 40 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should be perforated within the liner area, installed at the base and above the liner, be at least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner should consist of solid pipe. The penetration of the liners at the subdrains should be properly waterproofed. The subdrains should be connected to a proper outlet. The devices should also be installed in accordance with the manufacturer's recommendations. Storm Water Standard Worksheets Th~ SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility Condition (Worksheet C.4-1 or 1-8) worksheet information to help evaluate the potential for infiltration on the property. The attached Worksheet 1-8 presents the completed information for the submittal process. The regional storm water standards also have a worksheet (Worksheet D.5-1 or Form 1-9) that helps the project civil engineer estimate the factor of safety based on several factors. Table C-5 describes the suitability assessment input parameters related to the geotechnical engineering aspects for the factor of safety determination. Project No. 02245-52-01 -C-5 -April 8, 2019 TABLE C-5 SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY SAFETY FACTORS Consideration High Medium Low Concern -3 Points Concern - 2 Points Concern - 1 Point Use of soil survey maps or Use of well permeameter or borehole methods with simple texture analysis to accompanying Direct measurement with estimate short-term continuous boring log. localized (i.e. small- infiltration rates. Use of Direct measurement of scale) infiltration testing Assessment Methods well permeameter or infiltration area with methods at relatively high borehole methods without localized infiltration resolution or use of accompanying continuous measurement methods extensive test pit boring log. Relatively ( e.g., Infiltrometer). infiltration measurement sparse testing with direct methods. infiltration methods Moderate spatial resolution Predominant Soil Silty and clayey soils Loamy soils Granular to slightly Texture with significant fines loamy soils Highly variable soils Soil boring/test pits Soil boring/test pits indicated from site Site Soil Variability assessment or unknown indicate moderately indicate relatively variability homogenous soils homogenous soils Depth to Groundwater/ <5 feet below 5-15 feet below > 15 feet below Impervious Layer facility bottom facility bottom facility bottom Based on our geotechnical investigation and the previous table, Table C-6 presents the estimated factor values for the evaluation of the factor of safety. This table only presents the suitability assessment safety factor (Part A) of the worksheet. The project civil engineer should evaluate the safety factor for design (Part B) and use the combined safety factor for the design infiltration rate. TABLE C-6 FACTOR OF SAFETY WORKSHEET DESIGN VALUES -PART A1 Suitability Assessment Factor Category Assigned Factor Product Weight (w) Value (v) (p =w xv) Assessment Methods 0.25 2 0.50 Predominant Soil Texture 0.25 2 0.50 Site Soil Variability 0.25 3 0.75 Depth to Groundwater/ Impervious Layer 0.25 2 0.50 Suitability Assessment Safety Factor, SA= LP 2.25 1 The project civil engineer should complete Worksheet D.5-1 or Form 1-9 using the data on this table. Additional information is required to evaluate the design factor of safety. Project No. 02245-52-0 l -C-6 -April 8, 2019 Categorization of Infiltration Feasibility Condition Form I-8 Pan t -Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria Screening Question Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors prese nted in Appendix C.2 and Appendix D. Provide basis: Yes No X We performed 2 Aardvark Permeameter tests at the site within the Old Paralic Deposits within the low end of the site where storm water devices will likely be installed. The fo llowing presents the results of our fie ld infiltration tests: P-l at 2 feet: 0.008 inches/hour (0.004 inches/hour with FOS=2) P-2 at 2 feet: 0.183 inches/hour (0.092 inches/hour with FOS=2) These tests result in an average of0.096 inches/hour (0 .048 inches/hour with an app lied factor of safety of2). Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 2 Can in.filtration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Geologic hazards do not exist at the site that would preclude infiltration. X Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data so urce applicability. Project No. G2245 -52-0 I -C-7 -April 8, 20 I 9 Criteria 3 Provide basis: Worksheet C.4-1 Page 2 of 4 Screening Question Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a compre hensive evaluation of the factors presented in Appendix C.3. Yes No X We encountered groundwater during the site investigation at depths ranging from 7½ and 11 ½ feet below the existing grade. Therefore, infiltration should be considered infeasible at the site Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 4 Provide basis: Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. X We do not expect infiltration will cause water balance issues such as seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Part 1 Result* If all answers to rows 1 -4 are ''Yes" a full infiltration design is potentially feasible. The feasibility screening category is Full Inftltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 No Full Infiltration *To be completed using ga thered site information and bes t professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by the City to substantiate findings. Project No. G2245-52-0 I -C-8 -April 8, 2019 Worksheet C.4-1 Page 3 of 4 Part 2-Partial Infiltration vs. No Infiltration Feasibility ScreeningCriteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria 5 Provide basis: Screening Question Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Yes No X We performed 2 Aardvark Permeameter tests at the site within the Old Paralic Deposits within the low end of the site where storm water devices will likely be installed. The following presents the results of our field infiltration tests: P-l at 2 feet: 0.008 inches/hour (0.004 inches/hour with FOS=2) P-2 at 2 feet: 0.183 inches/hour (0.092 inches/hour with FOS=2) These tests result in an average of 0.096 inches/hour (0.048 inches/hour with an applied factor of safety of 2). The average infiltration rate at the site is less than 0.05 inches/hour, therefore, partial infiltration should be considered infeasible. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Provide basis: Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Geologic hazards do not exist at the site that wo uld preclude in filtration. X Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates . Project No. 02245-52-0 l -C-9 -April 8, 2019 Criteria 7 Provide basis: Worksheet C.4-1 Page 4 of 4 Screening Question Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Yes No X We encountered groundwater during the site investigation at depths ranging from 7½ and 11 ½ feet below the existing grade. Therefore, infiltration should be considered infeasible at the site. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narra tive discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Provide basis: Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. X We did not provide a study regarding water rights. However, these rights are not typical in the San Diego County area. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 1-4 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then in filtration o f any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. No Infiltration *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by the City to substantiate findings. Project No. G2245-52-0 I -C-1 0 -April 8, 201 9 ~GEOCO Reading 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 C: 0 ~-0. C: E ·-:I!. VI M C: C: 0:.:,. u cu ... ... cu ~ ... a:: ~ 3: Aardvark Permeameter Data Analysis Date: 2/8/2018 ------------, By: LR -:R::-e-:f.-:E'.":"L"".'(f;:-e-et:-, -:-M:-::S::--L:-): •---4-2.-0---. -------~ Bottom EL (feet, MSL): 41.8 : 4.25 Borehole Diameter, d (in.) Borehole Depth, H (feet) : 2.00 Wetted Area, A (in2):._! __ ...:8;.:9...:.6.;;.8.;;._ _ ___. Distance Between Reservoir & Top of Borehole (in.) : 29.00 Time (min) 0 5 10 15 20 25 30 35 40 Depth to Water Table, s (feet) Height APM Raised from Bottom (in.) Pressure Reducer Used : : : 50.00 2.00 No Distance Between Resevoir and APM Float, D (in.): Head Height Calculated, h (in.): Head Height Recorded, h (in.): Distance Between Constant Head and Water Table, L (in.): Time Elapsed Reservoir Water Resevoir Water Interval Water (min) Weight (g) Weight (lbs) Consumption (lbs) 17.625 5.00 17.605 0.020 5.00 17.575 0.030 5.00 17.570 0.005 5.00 17.560 0.010 5.00 17.555 0.005 5.00 17.550 0.005 5.00 17.545 0.005 5.00 17.540 0.005 46.25 5.65 5.50 581.65 *Water Total Water Consumption Rate Consumption (lbs) (in3/min) 0.020 0.111 0.050 0.166 0.055 0.D28 0.065 0.055 0.070 0.028 0.075 0.028 0.080 0.028 0.085 0.028 Steady Flow Rat e, Q (in3/min): 0.028 0.2 0.2 0.1 0.1 __...,-,. ~ "\.. "\.. ' ~ ------0.0 0 5 10 15 20 25 30 35 40 45 Time (min) Field-Saturated Hl£draulic Conductivitl!'. {Infiltration Ratel Case 1: L/h > 3 K,a, = I l.40E-04 lin/min 0.008 jin/hr <e GEOCO Aardvark Permeameter Data Analysis Project Name: 2690 Roosevelt Street ------------Project Number: G2245-52-01 Date: 2/8/2018 Borehole Location: -==:::::::;:::==-:p::-_:2---:===~ By: LR Ref. EL (feet, MSL): 41.0 Reading 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 C: .5! ... -0. C: E ·- ::it "'"' C: C: o:.:.. u cu ... ... cu IQ ... a:: IQ 3 --------- Bottom EL (feet, MSL): 40.8 : 4.25 Borehole Diameter, d (in.) Borehole Depth, H (feet) : 2.00 Wetted Area, A (in2):,_! ___ 10_2_._94 __ _. Distance Between Reservoir & Top of Borehole (in.) : 28.00 Time (min) 1 6 11 16 21 26 31 36 Depth to Water Table, s (feet) Height APM Raised from Bottom (in.) Pressure Reducer Used : : : 50.00 3.00 No Distance Between Resevoir and APM Float, D (in.): Head Height Calculated, h (in.): Head Height Recorded, h (in.): Distance Between Constant Head and Water Table, L (in.): Time Elapsed Reservoir Water Resevoir Water Interval Water (min) Weight (g) Weight (lbs) Consumption (lbs) 16.875 5.00 16.734 0.141 5.00 16.609 0.126 5.00 16.473 0.136 5.00 16.337 0.136 5.00 16.201 0.136 5.00 16.066 0.136 5.00 15.930 0.136 44.25 6.65 6.50 582.65 Total Water Consumption (lbs) 0.141 0.266 0.402 0.538 0.674 0.809 0.945 Steady Flow Rate, Q (in3 /min): 1.0 0.8 0.6 0.4 0.2 0.0 0 5 10 15 Field-Saturated Hydraulic Conductivity (Infiltration Ratel 20 Time (min) 25 30 35 *Water Consumption Rate (in3/min) 0.779 0.696 0.751 0.751 0.751 0.751 0.751 0.751 40 Case 1: L/h > 3 K sat = ,___3_.0_5_E_-_o_3 _ _.I in/min ___ o_.1_8_3 __ _.I in/hr APPENDIX \ APPENDIX D RECOMMENDED GRADING SPECIFICATIONS FOR 2690 ROOSEVELT STREET CARLSBAD, CALIFORNIA PROJECT NO. G2245-52-01 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. 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, and/or 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. 2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. GI rev. 07/2015 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. 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 GI rev. 07/2015 and 1 O; 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 1 ½ inches in diameter shall be removed to a de_pth of 3 feet below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials. 4.2 Asphalt pavement material removed during clearing operations should be properly disposed at an approved off-site facility or in an acceptable area of the project evaluated by Geocon and the property owner. 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. GI rev. 07/2015 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: I (horizontal :vertical), or where recommended by the Consultant, the original ground should be benched in accordance with the following illustration. TYPICAL BENCHING DETAIL Finish Grade Remove All Unsuitable Material As Recommended By Consultant Slope To Be Such That Sloughing Or Sliding Does Not Occur Original Ground / Finish Slope Surface -1 '----~=-==-~ I "B" See Note 1 See Note 2 No Scale DETAIL NOTES: (I) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. 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. GI rev. 07/2015 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. 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. 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. 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. GI rev. 07/2015 6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed at least ~ 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. 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. GI rev. 07/2015 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 provide_p 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 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, 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 aqd 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 GI rev. 07/2015 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. 7. SUBDRAINS 7.1 The geologic units on the site may have permeability characteristics and/or fracture systems that could be susceptible under certain conditions to seepage. The use of canyon subdrains may be necessary to mitigate the potential for adverse impacts associated with seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500 feet in length should use 6-inch-diameter pipes. GI rev. 07/2015 TYPICAL CANYON DRAIN DETAIL .............................. ~ --NAT\JRAl,.GROlN) ~.,,,.,,,,,.'.,,,,- .......... .................. .......... ..... .................... __ _ --- NOTES: 1 ...... 6-INQ-I DIAMETER, SCHEDULE 80 PVC PERFORATED PIPE FOR FILLS IN EXCESS OF 100-FEET IN DEPTH OR A PIPE LENGTH OF LONGER THAN 500 FEET. 2. ..... 11--INCH DIAMETER, SCHEDULE 40 PVC PERFORATED PIPE FOR AUS LESS THAN 1~EET IN OEPl1-i OR A PIPE l.ENGTii SHORTER THAN 500 FEET. .,-' .," ., ,,. .,-'., ,,..,,,. ,,. BEDROCK NOTE: FINAi. 711 Of' PIPE AT OUTlET 8HALL l!E -.-<JRATED. 9 CllllC Fl!eT / POOT Of' OP!N GRADED GAAV6. SURROUNDED BY MIRAFl 1<40NC (OR EQUIVAU:NT) FILTER FAIIRJC NO SCALE 7 .2 Slope drains within stability fill keyways should use 4-inch-diameter ( or lager) pipes. GI rev. 07/2015 TYPICAL STABILITY FILL DETAIL DETAIL NOTES: FORMATIONAL MATERJAL 1..._l!XCAVAT!! IACKCUT AT 1:1 INCUNAllON (U~ OTHl!RWll!I! NOT!D}. 2 .. ..JIASE OF STABILITY FILL TO BE 3 FEET MO FORMATIOfML MATI:RIAL. Bl.OPING A MINIMUM 5% INTO SI.OPE. 3.-.STA811.JTY FIJ. TO BE COMF"OSED OF PflOPERL Y COMPACTED GIWtLlAA SOIL. 4 ..... CHIMNEY DRAINS TO BE APPROVED PREFABRICATED 011MNEY DRIIIN PANELS (MIRADRAIN G2CUI OR EQUIVALENT) SPACED l>.PPROXIMl\lELY 20 FEET CEHTER TO CEHlER AND 4 FEETWIDE. O.OSER ~MAYBE REQUIRED F SEEPAGE IS ENCOUNTERED. 5.,-FIL TER MATERIAL TO BE 314-NCH. OPEN-ORAOED CRUStiED ROCK ~CLOSED IN APPROVED Fl. TER F~ (MIAAFI 1-40NC). 6,._.COUECTOR PIPE TO BE 4-INCH MINNUM DIAMETER, PERFORATED, THICK-WAUED PYC SCHEDU.E 40 OR EQUIVALENT, AND 9l.OPEI) TO DRAIN AT 1 Pl:ACENT YNUJM TO APPACWD oun.ET. NO SCALE 7.3 The actual subdrain locations will be evaluated in the field during the remedial grading operations. Additional drains may be necessary depending on the conditions observed and the requirements of the local regulatory agencies. Appropriate subdrain outlets should be evaluated prior to finalizing 40-scale grading plans. 7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to mitigate the potential for buildup of water from construction or landscape irrigation. The subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric. Rock fill drains should be constructed using the same requirements as canyon subdrains. GI rev. 07/2015 7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during future development should consist of non-perforated drainpipe. At the non-perforated/ perforated interface, a seepage cutoff wall should be constructed on the downslope side of the pipe. TYPICAL CUT OFF WALL DETAIL FRONT VIEW • • • ~-•:-,,· .: :\\· '.}~:. CONCRETE CUT-OFFWAU. · ~-, :0,·;r:<,jJ.=~.~f-: _......_ SIDE VIEW CONCRETE CUT-OFF WALL 80UO SUIID-Pl'E ll'MIN. 11'-.(TYP) ..... (TYP) NO SCALE NO SCALE 7.6 Subdrains that discharge into a natural drainage course or open space area should be provided with a permanent headwall structure. Gl rev. 07/2015 TYPICAL HEADWALL DETAIL FRONT VIEW SIDE VIEW rORr SUIDRAIN C0NCREre HEADWAU. NO"TE: HEADWAU. SHOULD OUTl.ET AT TOE OF Fill. SLOF'E OR INTO CONTROi.LEO SURFACE ORAINAGE NO SCALE 12" NO SCALE 7.7 The final grading plans should show the location of the proposed subdrains. After completion of remedial excavations and subdrain installation, the project civil engineer should survey the drain locations and prepare an "as-built" map showing the drain locations. The final outlet and connection locations should be determined during grading operations. Subdrains that will be extended on adjacent projects after grading can be placed on formational material and a vertical riser should be placed at the end of the subdrain. The grading contractor should consider videoing the subdrains shortly after burial to check proper installation and functionality. The contractor is responsible for the performance of the drains. GI rev. 07/2015 8. OBSERVATION AND TESTING 8.1 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. 8.2 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. 8.3 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. 8.4 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. 8.5 We should observe the placement of subdrains, to check that the drainage devices have been placed and constructed in substantial conformance with project specifications. 8.6 Testing procedures shall conform to the following Standards as appropriate: 8.6.1 Soil and Soil-Rock Fills: 8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the Sand-Cone Method. GI rev. 07/2015 8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth). 8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer and 18-lnch Drop. 8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test. 9. PROTECTION OF WORK 9 .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. 9.2 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. 10. CERTIFICATIONS AND FINAL REPORTS 10.1 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. 10.2 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. GI rev. 07/2015 LIST OF REFERENCES 1. 2016 California Building Code, California Code of Regulations, Title 24, Part 2, based on the 2015 International Building Code, prepared by California Building Standards Commission, dated July, 2016. 2. AC! 318-14, Building Code Requirements for Structural Concrete and Commentary on Building Code Requirements for Structural Concrete, prepared by the American Concrete Institute, dated September, 2014. 3. AC! 330-08, Guide for the Design and Construction of Concrete Parking Lots, American Concrete Institute, June 2008. 4. Anderson, J. G., T. K. Rockwell, and D. C. Agnew, Past and Possible Future Earthquakes of Significance to the San Diego Region: Earthquake Spectra, v. 5, no. 2, p. 299-333, 1989. 5. ASCE 7-10, Minimum Design Loads for Buildings and Other Structures, Second Printing, April 6, 2011. 6. Boore, D. M., and G. M Atkinson (2008), Ground-Motion Prediction for the Average Horizontal Component of PGA, PG V, and 5'¼-Damped PSA at Spectral Periods Between 0.01 and 10.0 S, Earthquake Spectra, Volume 24, Issue 1, pp. 99-138, February 2008. 7. California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic Hazard Assessment for the State of California, Open File Report 96-08, 1996. 8. California Emergency Management Agency, California Geological Survey, University of Southern California (2009). Tsunami Inundation Map for Emergency Planning, State of California, County of San Diego, Point Loma Triangle, Scale 1:24,000, dated June 1. 9. California Geologic Survey, State of California Earthquake Fault Zones, Point Loma Quadrangle, May 1, 2003. 10. California Geologic Survey (2008), Special Publication 117, Guidelines For Evaluating and Mitigating Seismic Hazards in California, Revised and Re-adopted September 11. 11. Campbell, K. W., and 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. 12. Chiou, Brian S. J., 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. 13. 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. Project No. G2245-52-0 l April 8, 2019 LIST OF REFERENCES (Concluded) 14. Kennedy, M. P., and S.S. Tan, 2008, Geologic Map of Oceanside 30'x60' Quadrangle, California, USGS Regional Map Series Map No. 2, Scale 1:100,000. 15. Risk Engineering, EZFRISK, 2015. 16. Structural Engineers Association of California (SEAOC) and Office of Statewide Health Planning and Development (OSHPD), Seismic Design Maps, https://seismicmaps.org/, accessed January 11, 2019. 17. Unpublished Geotechnical Reports and Information, Geocon Incorporated. Project No. 02245-52-0 l April 8, 2019