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HomeMy WebLinkAboutCT 2018-0003; MAGNOLIA BRADY; GEOTECHNICAL INVESTIGATION; 2018-01-17I I ! I I I I I I I I I I I I I I I j I I I I I I I I I I 111 I 11 I I I I I I I I I I I I I I I t I I I I I I GEOTECHNICAL INVESTIGATION 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA l,. --\1 ED OC T O ~ 2019 LAND DEVELOP\ti~NT ENGINEERlr G PREPARED FOR ASTHON 3, LLC RANCHO MISSION VIEJO, CALIFORNIA JANUARY 17, 2018 PROJECT NO. G2192-52-01 ~ \i GEOCON INCORPORATED GEOTECHNICA L ■ Project No. G2l92-52-01 January 17, 2018 Ashton 3, LLC 5 Hoya Street Rancho Mission Viejo, California 92694 Attention: Mr. Taylor Ashton Subject: GEOTECHNICAL INVESTIGATION 1534 MAGNOLIA A VENUE CARLSBAD, CALIFORNIA Dear Mr. Ashton: In accordance with your request, we performed this geotechnical investigation for the proposed 7-lot residential development in Carlsbad, California. The accompanying report presents the results of our study and our conclusions and recommendations regarding the geotechnical aspects of project development. The results of our study indicate that the site can be developed as planned, 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 INCORPORATED MRL:SFW:JH:dmc (e-mail) (3) Addressee Mr. Robert C. Ladwig &e~ GE 2714 6960 Flanders Drive ■ San Diego, California 92121-2974 ■ Telephone 858.558.6900 ■ Fax 858.558.6159 TABLE OF CONTENTS 1. PURPOSE AND SCOPE ................................................................................................................. I 2. SITE AND PROJECT DESCRIPTION ........................................................................................... 1 3. GEOLOGIC SETTING .................................................................................................................... 2 4. SOIL AND GEOLOGIC CONDITIONS ........................................................................................ 2 4.1 Undocumented Fill (Qudf) .................................................................................................... 2 4.2 Old Paralic Deposits (Qop) .................................................................................................... 2 5. GROUNDWATER .......................................................................................................................... 3 6. GEOLOGIC HAZARDS ................................................................................................................. 3 6.1 Faulting and Seismi city ......................................................................................................... 3 6.2 Ground Rupture ..................................................................................................................... 5 6.3 L iquefaction ........................................................................................................................... 5 6.4 Seiches and Tsunamis ............................................................................................................ 6 6.5 Landslides .............................................................................................................................. 6 7. CONCLUSIONS AND RECOMMENDATIONS ........................................................................... 7 7.1 General ................................................................................................................................... 7 7.2 Excavati on and Soil Characteri stics ...................................................................................... 8 7.3 Grading .................................................................................................................................. 9 7 .4 Temporary Excavations ....................................................................................................... l 0 7.5 Seismic Design Criteria ....................................................................................................... 10 7.6 Shallow Foundations ........................................................................................................... 12 7.7 Concrete Slabs-on-Grade ..................................................................................................... 13 7.8 Post-Tensioned Foundation System Recommend ations ...................................................... 14 7 .9 Concrete Flatwork ............................................................................................................... 16 7.10 RetainingWalls ................................................................................................................... 17 7.1 1 Lateral Loading .................................................................................................................... 18 7.12 Preliminary Pavement Recommendations ........................................................................... 19 7.13 Site Drainage and Moisture Protecti on ................................................................................ 22 7.1 4 Gradin g, Improvement and Foundation Plan Rev iew .......................................................... 22 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, Typical Retaining Wall Drain Detail APPENDIX A FIELD INVESTIGATION F igures A-1 -A-9, Exploratory Trench Logs TABLE OF CONTENTS (Concluded) APPENDIX B LABO RA TORY TESTING Table B-1, Summary of Laboratory Maximum Density and Optimum Moisture Content Results Table B-II, Summary of Laboratory Direct Shear Results Table B-III, Summary of Laboratory Expansion Index Test Results Table B-IV, Summary of Laboratory Water-Soluble Su lfate Test Results Table B-V, Summary of Laboratory Resistance Value (R-Value) Test Results Figure B-1 , Gradation Curves APPENDIX C STORM WATER MANAGEMENT INVESTIGATION APPENDIX D RECOMMENDED GRADING SPECIFICATIONS LIST OF REFERENCES GEOTECHNICAL INVESTIGATION 1. PURPOSE AND SCOPE This report presents the results of our geotechnical investigation for the proposed residential development located at 1534 Magnolia A venue in the City of Carlsbad, California (see Vicinity Map, Figure 1). The purpose of this geotechnical investigation is to evaluate the surface and subsurface soil conditions, general site geology, and to identify geotechnical constraints that may impact the planned improvements to the property. In addition, this report provides recommendations for the 2016 CBC seismic design criteria, grading, pavement, shallow foundations, concrete slabs-on-grade, concrete flatwork, retaining wall s, lateral loads, and storm water best management practices (BMP) recommendations; and discussions regarding the local geologic hazards including faulting and seismic shaking. This report is limited to the area proposed for the construction of the new development and associated improvements as shown on the Geologic Map, Figure 2. We used the preliminary grading plan prepared by Civil Landworks (2018) as the base for the Geologic Map. The scope of this investigation included rev1ewmg readily available published and unpublished geologic literature (see List of References); performing engineering analyses; and preparing of this report. We also advanced 9 exploratory trenches to a maximum depth of about 12 feet, performed percolation/infiltration testing, sampled soil and performed laboratory testing. Appendix A presents the exploratory trench logs and details of the field investigation. The details of the laboratory tests and a summary of the test results are shown in Appendix B and on the trench logs in Appendix A. Appendix C presents a summary of our storm water management investigation. 2. SITE AND PROJECT DESCRIPTION The site is located at the northeast comer of Magnolia Avenue and Brady Circle and can be accessed from both streets. A residential structure exists in the northeast corner of the site. The remainder of property is covered with seasonal grasses and shrubs and appears to have remained undeveloped for at least the last 50 years. The property is relatively flat and gently descends to the southwest at elevations of about 150 to 160 feet above mean sea level (MSL). We understand the planned development includes constructing 7 residential lots with associated utilities, driveways, storm water basins and landscaping. Access to the lots will be from Brady Circle. Maximum cut and fill depths are on the order of 2 feet across the site and up to 5 feet for the proposed biofiltration basins. We expect the proposed structures would likely be supported on conventional shallow or post-tensioned foundation systems founded in properly compacted fill. Project No. 02192-52-0 I -I -January 17, 2018 Individual lot storm water management devices will be constructed on the property and will likely be extended into the Old Parali c Deposits materials. 3. GEOLOGIC SETTING The site is located in the western portion of the coastal plain within the southern portion of the Peninsular Ranges Geomorphi c Province of south ern 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 Cali fornia to the south. The coastal plain of San Diego County is underlai n by a th ick sequence of re latively 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 twenty-one, stair-stepped marine terraces (youn ger to the west) that have been di ssected by west flowing rivers. The coastal plain is a relatively stable block that is di ssected 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. 4. SOIL AND GEOLOGIC CONDITIONS We encountered undocumented fill (Qudf) associated with the existing development overlying Old Paralic Deposits (Qop). The trench lo gs (Appendix A) and the Geologic Map (F igure 2), show the approximate occurrence, distribution, and description of each unit encountered during our field investigation. The surficial so il and geologic units are described herein in order of increasing age. 4.1 Undocumented Fill (Qudf) We encountered undocumented fill in all of our exploratory trenches that varied in thickness between ½ and 3 feet. The fi ll generally consists of loose, dry to damp, light brown to reddish brown, silty sand and possess a "very low" to "low" expansion potential ( expansion index of 50 or less). These materials are un suitab le in their present condition, and will req uire remedial grading in the areas of the proposed improvements. 4.2 Old Paralic Deposits (Qop) The Quaternary-age Old Paralic Deposits exist below the undocumented fill across the site. These deposits generally consist of med ium dense to dense, light to dark reddish brown and olive brown, silty to clayey, fine to medium sand and stiff, olive brown, sandy clay. The Old Paralic Deposits typically possess a "very low" to "medium" expansion potential ( expansion index of 90 or less) and a Project No. 02192-52-01 -2 -January 17, 20 18 "SO" sulfate class. The Old Paralic Deposits are considered acceptable to support the planned fill and foundation loads for the development. 5. GROUNDWATER We did not encountered groundwater during our field investigation to the maximum depth explored of 12 feet. We expect groundwater is present at depths of greater than 50 feet. We do not expect groundwater to significantly impact project development as presently proposed. It is not uncommon for groundwater or seepage conditions to develop where none previously existed. Groundwater and seepage is dependent on seasonal precipitation, irrigation, land use, among other factors, and varies as a result. Proper surface drainage wi ll be important to future performance of the project. 6. GEOLOGIC HAZARDS 6.1 Faulting and Seismicity Based on our site investigation and a review of published geologic maps and reports, the site is not located on known active, potentially active or inactive fault traces as defined by the California Geological Survey (CGS). The CGS considers a fault seismically active when evidence suggests seismic activity within roughly the last 11 ,000 years. 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. The Rose Canyon Fault zone and the Newport-Inglewood Fault are the closest known active faults, located approximately 7 miles west of the site. Earthquakes that might occur on the Newport-Inglewood or Rose Canyon Fault Zones 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 0.36g, respectively. Table 6.1.1 lists the estimated maximum earthquake magnitude and peak ground acceleration for the most dominant fau lts in relationship to the site location. We calculated peak ground acceleration (PGA) using Boore-Atkinson (2008) NGA USGS 2008, Campbell-Bozorgnia (2008) NGA USGS 2008, and Chiou-Youngs (2007) NGA USGS 2008 acceleration-attenuation relationships. Project No. G2 I 92-52-0 I -3 -January 17, 2018 TABLE 6.1 .1 DETERMINISTIC SPECTRA SITE PARAMETERS Maximum Peak Ground Acceleration Fault Name Distance from Earthquake Boore-Campbell-Chiou-Si te (miles) Magnitude Atkinson Bozorgnia Youngs (Mw) 2008 (g) 2008 (g) 2007 (g) Newport-Inglewood 7 7.50 0.30 0.29 0.3 6 Rose Canyon 7 6.90 0.26 0.28 0.30 Coronado Bank 21 7.40 0.15 0.11 0.13 Palos Verdes Connected 21 7.70 0.17 0.12 0.15 Elsinore 22 7.85 0.17 0.12 0.16 Palos Verdes 35 7.30 0.10 0.07 0.07 San Joaquin Hills 35 7.10 0.09 0.09 0.07 Earthquake Valley 43 6.80 0.06 0.05 0.04 San Jacinto 47 7.88 0.10 0.07 0.09 Chino 47 6.80 0.06 0.04 0.03 We used the computer program EZ-FRISK to perform a probabilistic seismic hazard analysis. The computer program EZ-FRISK operates under the assumpti on that the occurrence rate of earthquakes on each mappable Quaternary fault is proportional to the fau lts 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 fo r 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 the analysis. Table 6.1.2 presents the site-specific probabilistic seismic hazard parameters including acceleration-attenuation relationships and the probability of exceedence. Project No. G2192-52-01 -4 -January 17, 2018 TABLE 6.1.2 PROBABILISTIC SEISMIC HAZARD PARAMETERS Peak Ground Acceleration Probability of Exceedence Boore-Atkinson, Cam pbell-Bozorgnia, Chiou-Youngs, 2008 (g) 2008 (g) 2007 (g) 2% in a 50 Year Period 0.44 0.44 0.50 5% in a 50 Year Period 0.32 0.32 0.35 I 0% in a 50 Year Period 0.24 0.23 0.25 While listing peak accelerations is useful for comparison of potential effects of fault activity in a region, other considerations are important in seismic design, including the frequency and duration of motion and the soil conditions underlying the site. Seismic design of the structures should be evaluated in accordance with the 2016 California Building Code (CBC) guidelines currently adopted by the City of Carlsbad. The site could be subjected to moderate to severe ground shaking in the event of a major earthquake on any of the referenced faults or other faults in Southern California. With respect to seismic shaking, the site is considered comparable to the surrounding developed area. 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 the earth surface. The potential for ground rupture is considered to be negligible due to the absence of active faults at the subject site. 6.3 Liquefaction Liquefaction typically occurs when a site is located in a zone with seismic activity, onsite soil is cohesionless or silt/clay with low plasticity, groundwater is encountered within 50 feet of the surface, and soil re lative densities are less than about 70 percent. If the four of the previous criteria are met, a seismic event could result in a rapid pore-water pressure increase from the earthquake-generated ground accelerations. Seismically induced settlement may occur whether the potential for liquefaction exists or not. The potential for liquefaction and seismically induced settlement occurring within the site soil is considered to be very low due to the age and dense nature of the Old Paralic Deposits and the lack of a permanent groundwater table within the upper 50 feet. Project No. 02192-52-0 I -5 -January 17, 2018 6.4 Seiches and Tsunamis Seiches are free or standing-wave oscillations of an enclosed water body that continue, pendulum fashion, after the original driving forces have dissipated. Seiches usually propagate in the direction of longest axis of the basin. The site located approximately 1 mile from Agua Hedonia Lagoon and is at a minimum elevation of approximately 150 feet above Mean Sea Level (MSL); therefore, the potential of seiches to occur is considered to be very 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 may include underwater earthquakes, volcanic eruptions or offshore slope failures . the property is at an elevation of above 150 feet MSL and about 1 mile from the Pacific Ocean. Therefore, the potential for the site to be affected by a tsunami is negligible. 6.5 Landslides We did not observe evidence of ancient landslide deposits at the site during the geotechnical investigation. Based on observations during our field investigation, it is our opinion that landslides are not present at the subject property or at a location that could impact the proposed development. Proj ect No. 02192-52-01 -6 -January 17, 2018 7. CONCLUSIONS AND RECOMMENDATIONS 7.1 General 7.1.1 From a geotechnical engineering standpoint, we opine the site is suitable for the proposed residential development provided the recommendations presented herein are implemented in design and construction of the project. 7.1.2 With the exception of possible moderate to strong seismic shaking, we did not observe significant geologic hazards or know of them to exist on the site that would adversely affect the proposed project. 7.1.3 Our field investigation indicates the site is underlain by undocumented fill overlying Old Paralic Deposits. The undocumented fill is unsuitable in the present condition and will require remedial grading where improvements are planned as discussed herein. We should evaluate the actual extent of unsuitable soil removal in the field during the grading operations. 7.1.4 We did not encounter groundwater during our field investigation to the maximum depth explored of 12 feet. We anticipate that groundwater is present at depths greater than 50 feet. We do not expect groundwater to significantly impact project development as presently proposed. 7 .1.5 The proposed development can be supported on conventional shallow or post-tensioned foundations bearing in compacted fill materials. 7.1.6 We performed a storm water management investigation to help evaluate the potential for infiltration on the property. Based on the infiltration rates measured during our field investigation, we opine full infiltration on the property should be considered infeasible. However, partial infiltration may be considered feasible within the Old Paralic Deposits as discussed in Appendix C. 7.1 .7 Based on our review of the conceptual 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. Project No. G2 l 92-52-0 I -7 -January 17, 201 8 7.2 Excavation and Soil Characteristics 7.2.1 Excavation of the undocumented fill and Old Paralic Deposits should be possible with light to moderate effort using conventional heavy-duty grading eq uipment. 7.2.2 The soil encountered in the field investigation is considered to be "non-expansive" to "expansive" (expansion index [EI] of 20 or less or greater than 20, respectively) as defined by 2016 California Building Code (CBC) Section I 803.5.3 based on our test results. Table 7.2 presents soi l classifications based on the expansion index. We expect the existing site materials possess a "very low" to "low" expansion potential (expansion index of 50 or less) in accordance with ASTM D 4829. TABLE 7.2 EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (El) ASTM D 4829 Soil 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 laboratory tests on soil samples to evaluate the water-soluble sulfate content (California Test No. 417) to generally evaluate the corrosion potential to structures in contact with soil. Results from the laboratory water-soluble su lfate content tests indicate that the materials at the locations tested possesses "SO" su lfate exposure to concrete structures as defined by 2016 CBC Section 1904 and ACI 318-11 Sections 4.2 and 4.3. 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. Appendi x B presents the results of the laboratory tests. 7.2.4 Geocon Incorporated does not practice in the field of corrosion engineering; therefore, further evaluation by a corrosion engineer may be needed to incorporate the necessary precautions to avoid premature corrosion of underground pipes and buried metal in direct contact with the soils. Project No. G2192-52-0 I -8 -January 17, 2018 7.3 Grading 7.3.1 The grading operations should be performed in accordance with the attached Recommended Grading Specifications (Appendix D). Where the recommendations of thi s section conflict with Appendix D, the recommendations of this section take precedence. We should observe and test earthwork for proper compaction and moisture content. 7.3.2 A pre-construction meeting with the city inspector, owner, general contractor, civil engineer and geotechnical engineer should be held at the site prior to the beginning of grading and excavation operations. Special soil handling requirements can be discussed at that time, if necessary. 7.3.3 We should observe the earthwork operations and test the compacted fill. 7.3.4 Grading of the site should commence with the demolition of existing structures, removal of existing improvements, vegetation, and deleterious debris. Deleterious debris should be exported from the site and should not be mixed with the fill. Existing underground improvements within the proposed structure area that extend below the planned grading limits should be removed and properly backfilled. 7.3 .5 The undocumented fill within the site boundaries should be removed to expose the underlying Old Paralic Deposits. We should evaluate the actual extent of unsuitable soil removals during the grading operations. Prior to fill soi l being placed, the existing ground surface should be scarified, moisture conditioned as necessary, and compacted to a depth of at least 12 inches. 7.3.6 To reduce the potential for differential settlement of the compacted fill, the residential building pads with cut-fill transitions should be undercut at least 3 feet and replaced with properly compacted fill. In addition, cut pads that expose the Old Paralic Deposits should also be undercut at least 3 feet to faci litate future trenching and provide a more uniform finish grade soil condition. 7.3.7 The site should then be brought to final subgrade elevations with fill compacted in layers. In general, soil native to the site is suitable for use from a geotechnical engineering standpoint as 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 in accordance with Project No. 02192-52-0 I -9 -January 17, 2018 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. 7.3.8 Import fill (if necessary) should consist of granular materials with a "very low" to "low" expansion potential (EI of 50 or less) free of deleterious material or stones larger than 3 inches and should be compacted as recommended above. 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. 7.4 Temporary Excavations 7.4.1 The recommendations included herein are provided for stable 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. Undocumented fill should be considered a Type C soil in accordance with OSHA requirements. The Old Paralic Deposits and compacted fill materials can be considered a Type B soil (Type C soil if seepage or groundwater is encountered). In general, special shoring requirements will not be necessary if temporary excavations will be less than 4 feet in height and raveling of the excavations does not occur. 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. Geocon can provide temporary shoring recommendations, if necessary. 7.5 Seismic Design Criteria 7.5. l We used the computer program US. Seismic Design Maps, provided by the USGS. Table 7 .5 .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 structures and improvements should be Project No. G2192-52-0 I -IO -January 17, 2018 designed using a Site Class C. We evalu ated 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. The values presented in Table 7.5.1 are for the risk-targeted maximum considered earthquake (MCER). TABLE 7.5.1 2016 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2016 CBC Reference Site Class C Section 1613 .3.2 MCER Ground Motion Spectral 1.127g Figure 1613.3.1(1) Response Acceleration -Class B (short), Ss MCER Ground Motion Spectral 0.433g Figure 1613.3.1(2) Response Acceleration -Class B (I sec), S1 Site Coefficient, FA 1.000 Table 1613.3 .3(1) Site Coefficient, Fv 1.367 Table 1613.3.3(2) Site Class Modified MCER Spectral 1.127g Section 1613.3.3 (Eqn 16-37) Response Acceleration (short), SMs Site Class Modified MCER Spectral 0.592g Section 1613.3.3 (Eqn 16-38) Response Acceleration (I sec), SM1 5% Damped Design Spectral 0.75 lg Section 1613.3.4 (Eqn 16-39) Response Acceleration (short), Sos 5% Damped Design Spectral 0.395g Section 1613.3.4 (Eqn 16-40) Response Acceleration (I sec), Soi 7.5.2 Table 7.5.2 presents additional seismic design parameters for projects located in Seismic Design Categories of D through F in accordance with ASCE 7-1 0 for the mapped maximum considered geometric mean (MCEG). TABLE 7.5.2 2016 CBC SITE ACCELERATION DESIGN PARAMETERS Parameter Value ASCE 7-10 Reference Mapped MCE0 Peak Ground Acceleration, PGA 0.443g Figure 22-7 Site Coefficient, FPGA 1.000 Table 11.8-1 Site Class Modified MCEG 0.443g Section 11.8.3 (Eqn 11.8-1) Peak Ground Acceleration, PGAM 7.5.3 Conformance to the criteria in Tables 7.5.1 and 7.5.2 for seismic design does not constitute any ki nd of guarantee or assurance that significant structural damage or gro und 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. G2I92-52-01 -11 -January 17, 2018 7.6 Shallow Foundations 7.6.1 The foundation recommendations herein are for the proposed residential structures founded in compacted fill. Foundations for the structure should consist of continuous strip footings and/or isolated spread footings. Continuous footings should be at least 18 inches wide and extend at least 18 inches below lowest adjacent pad grade. Isolated spread footings should have a minimum width of 24 inches and should extend at least 18 inches below lowest adjacent pad grade. Figure 3 presents a footing dimension detail depicting the depth to lowest adjacent grade. 7.6.2 Steel reinforcement for continuous footings should consist of at least four No. 4 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. The minimum reinforcement recommended herein is based on soil characteristics only (expansion index of 50 or less) and is not intended to replace reinforcement required for structural considerations. 7.6.3 The recommended allowable bearing capac ity for foundations with minimum dimensions described herein and bearing in properly compacted fill is 2,000 pound s per squ are foot (psf). The values presented herein are for dead plus live loads and may be increased by one-third when considering transient loads due to wind or seismic forces. 7.6.4 Total and differential settlement of the building founded on compacted fill materials 1s expected to be less than ½-inch for 6-foot footings. 7.6.5 Where buildings or other improvements are planned near the top of a slope 3:1 (horizontal to vertical) or steeper, special foundation and/or design considerations are recommended due to the tendency for lateral soil movement to occur. • Footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. • Although other improvements, which are relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to incorporate design measures which would permit some lateral so il movement without causing extensive distress. Geocon Incorporated should be consulted for specific recommendations. 7.6.6 We should observe the foundation excavations prior to the placement of reinforcing steel and concrete to check that the exposed soil conditions are similar to those expected and that Project No. 02192-52-0 I -12 -January 17, 2018 they have been extended to the appropriate bearing strata. Foundation modifications may be required if unexpected soil conditions are encountered. 7.6.7 Geocon Incorporated shou ld be consulted to provide additional design parameters as required by the structural engineer. 7.7 Concrete Slabs-on-Grade 7.7.1 Concrete slabs-on-grade for the structures should be at least 4 inches thick and reinforced with No. 3 steel reinforcing bars at 24 inches on center in both horizontal directions. 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 wi ll be installed and if the structure will possess a humidity controlled environment. 7.7.3 The bedding sand thickness should be detennined by the project foundation engineer, architect, and/or developer. However, we should be contacted to provide recommendations if the bedding sand is thicker than 6 inches. It is common to see 3 to 4 inches of sand below the concrete slab-on-grade for 5-inch thick slabs in the southern California area. The foundation design engineer should provide appropriate concrete mix design criteria and curing measures to assure proper curing of the slab by reducing the potential for rapid moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation design engineer present the concrete mix design and proper curing methods on the foundation plans. It is critical that the foundation contractor understands and fo llows the recommendations presented on the foundation plans. 7.7.4 Concrete slabs should be provided with adequate crack-control joints, construction joints and/or expansion joints to reduce unsightly shrinkage cracking. The design of joints should consider criteria of the American Concrete [nstitute (ACI) when establishing crack-control spacing. Crack-control joints should be spaced at intervals no greater than 12 feet. Additional steel reinforcing, concrete admixtures and/or closer crack control joint spacing should be considered where concrete-exposed finished floors are planned. Project No. 02192-52-01 -13 -January 17, 2018 7.7.5 The concrete slab-on-grade recommendations are based on soil support characteristics only. The project structural engineer should evaluate the structural requirements of the concrete slabs for supporting vehicle, equipment and storage loads. 7.7.6 The recommendations presented herein are intended to reduce the potential for cracking of slabs and foundations as a result of differential movement. However, even with the incorporation of the recommendations presented herein, foundations and slabs-on-grade will still exhibit some cracking. 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. Literature provided by the Portland Cement 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 Post-Tensioned Foundation System Recommendations 7.8.1 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) DC 10.5-12 Standard Requirements for Design and Analysis of Shallow Post-Tensioned Concrete Foundations on Expansive Soils or WRJ/CRSJ Design of Slab-on-Ground Foundations, as required by the 2016 California Building Code (CBC Section 1808.6.2). Although this procedure was developed for expansive soil conditions, it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post-tensioned design should incorporate the geotechnical parameters presented in Table 7.8. The parameters presented in Table 7.8 are based on the guidelines presented in the PTI DC 10.5 design manual. TABLE 7.8 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) 5.3 Edge Lift, YM (inches) 0.61 Center Lift Moisture Variation Distance, eM (feet) 9.0 Center Lift, YM (inches) 0.30 Project No. 02192-52-0 I -14 -January 17, 2018 7.8.2 Post-tensioned foundations may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf) (dead plus live load). This bearing pressure may be increased by one-third for transient loads due to wind or seismic forces. The estimated maximum total and differential settlement for the planned structures due to foundation loads is ½ inch. 7.8.3 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. 7.8.4 Isolated footings, if present, should have the minimum embedment depth and width recommended for conventional foundations. The use of isolated footings, which are located beyond the perimeter of the building and support structural elements connected to the building, are not recommended. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams. 7.8.5 Consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to reduce the potential for future separation to occur. 7.8.6 If the structural engineer proposes a post-tensioned foundation design method other than PTI, DC 10.5: • The deflection criteria presented in Table 7.8 are still applicable. • The width of the perimeter foundations should be at least 12 inches. • The perimeter footing embedment depths should be at least 18 inches. The embedment depths should be measured from the lowest adjacent pad grade. 7.8.7 Our experience indicates post-tensioned slabs may be 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. The structural engineer should design the foundation system to reduce the potential of edge lift occurring for the proposed structures. 7.8.8 During the construction of the post-tension foundation system, the concrete should be placed monolithically. Under no circumstances should cold joints form between the Project No. G2 I 92-52-0 I -15 -January 17, 20 18 footings/grade beams and the slab during the construction of the post-tension foundation system unless designed by the structural engineer. 7.8.9 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. The slab underlayment should be the same as previously discussed. 7.9 Concrete Flatwork 7.9.1 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 6 x 6 -W2.9/W2.9 (6 x 6 -6/6) welded wire mesh or No. 3 reinforcing bars spaced at least 18 inches center-to-center in both directions 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 presented in the grading section prior to concrete placement. Subgrade soil should be properly compacted and the moisture content of subgrade soil should be checked prior to placing concrete. 7.9.2 Even with the incorporation of the recommendations within this report, the exterior concrete flatwork has a likelihood of experiencing some uplift due to expansive soil beneath grade; 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. 7 .9 .3 Where exterior flatwork abuts the structure 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. Project No. 02192-52-01 -16 -January 17, 2018 7.10 7.10.1 7.10.2 7.10.3 7.10.4 7.10.5 Retaining Walls 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 with a density of 35 pounds per cubic foot (pct). Where the backfill will be inclined at no steeper than 2H: 1 V, an active soil pressure of 50 pcf is recommended. These soil pressures assume that the backfill materials within an area bounded by the wall and a 1: 1 plane extending upward from the base of the wall possess an expansion index of 50 or less. Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equal s 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 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. The structural engineer should determine the seismic design category for the project. If the project possesses a seismic design category of D, E, or F, the proposed retaining walls should be designed with seismic lateral pressure. A seismic load of 16H psf should be used for design of walls that support more than 6 feet of backfill 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. We used the peak site acceleration, PGAM, of0.443g calculated from ASCE 7-10 Section 11.8.3. 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. Retaining walls should be provided with a drainage system adequate to prevent the buildup of hydrostatic forces and should be waterproofed as required by the proj ect architect. The use of drainage openings through th e base of the wall (weep holes) is not recommended where the seepage could be a nuisance or otherwise adversely affect the property adjacent to the base of the wall. The recommendations herein assume a properly compacted free- draining backfill material (El of 50 or less) with no hydrostatic forces or imposed surcharge load. Figure 4 presents a typical retaining wall drain detail. If conditions different than Project No. G2 I 92-52-0 I -17 -January 17, 2018 7.10.6 7.10.7 7.10.8 7.10.9 7.11 7.11.1 those described are expected, or if specific drainage details are desired, Geocon Incorporated should be contacted for additional recommendations. Soil contemplated for use as retaining wall backfill, including import materials, should be identified in the field prior to backfill. At that time, Geocon Incorporated should obtain samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures may be necessary if the backfill soil does not meet the required expansion index or shear strength. City or regional standard wall designs, if used, are based on a specific active lateral earth pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may or may not meet the values for standard wall designs. Geocon Incorporated should be consulted to assess the suitability of the on-site soil for use as wall backfill if standard wall designs will be used. In general, wall foundations having a minimum depth and width of l foot may be designed for an allowable soil bearing pressure of 2,000 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. 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. The recommendations presented herein are generally applicable to the design of rigid concrete or masonry retaining walls having a maximum height of 8 feet. In the event that walls higher than 8 feet or 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. Lateral Loading To resist lateral loads, a passive pressure exerted by an equivalent fluid weight of 350 pounds per cubic foot (pct) should be used for the design of footings or shear keys poured neat in compacted fill. The 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. Project No. G2 I 92-52-0 I -18 -January 17, 2018 7 .11.2 7 .11.3 7.12 7.12.1 7.12.2 7.12.3 If friction is to be used to resist lateral loads, an al lowable coefficient of friction between soil and concrete of 0.35 should be used for design. The friction coefficient may be reduced to 0.2 to 0.25 depending on the vapor barrier or waterproofing material used for construction in accordance with the manufacturer's recommendations 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 and 6.0 for local and coll ector streets, respectively. The project civil engineer and owner should rev iew the pavement designations to determine appropriate locations for pavement thickness. The final pavement sections for the parking lot should be based on the R-Value of the subgrade soil encountered at final subgrade elevation. Based on the results of our R-Value testing of the subgrade soils, we assumed an R-Value of 44 and 78 for the subgrade soi l and base materials, respectively, for the purposes of this preliminary analysis. Table 7 .12.1 presents the preliminary flexible pavement sections. TABLE 7.12.1 PRELIMINARY FLEXIBLE PAVEMENT SECTION Assumed Assumed Asphalt Cla ss 2 Location Traffic Index Subgrade Concrete* Aggregate R-Value (inches) Base* (inches) Local Street 5.0 44 4 4 Coll ector Street 6.0 44 4 6 *Per City of Carlsbad Engineering Standards (2016) The subgrade soils for pavement areas should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above the optimum moisture content. The depth of subgrade compaction should be approximately 12 inches. Class 2 aggregate base should conform to Section 26-l-02B of the Standard Specifications for The State of California Department of Transportation (Ca/trans) and should be compacted to a min imum of 95 percent of the maximum dry density at near optimum Project No. G2192-52-0 I -19 -January 17, 2018 7.12.4 7.12.5 7.12.6 7.12.7 7.12.8 moisture content. The asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public Works Construction (Green book). 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 requested. A rigid Portland cement concrete (PCC) pavement section should be placed in driveway entrance aprons. 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 7.12.2. TABLE 7.12.2 RIGID PAVEMENT DESIGN PARAMETERS Design Parameter Design Value Modulus of subgrade reaction, k 100 pci Modulus ofrupture for concrete, MR 500 psi Traffic Category, TC A and C Average daily truck traffic, ADTT 1 and 100 Based on the criteria presented herein, the PCC pavement sections should have a minimum thickness as presented in Table 7.12.3 . TABLE 7.12.3 RIGID PAVEMENT RECOMMENDATIONS Location Portland Cement Concrete (inches) Driveways/ Automobile Parking Areas (TC=A) 5.0 Heavy Truck and Fire Lane Areas (TC=C) 7.0 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). 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 Project No. 02192-52-01 -20 -January 17, 20 18 7.12.9 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., a 7-inch-thick slab would have a 9-inch-thick edge). Reinforcing steel will not be necessary within the concrete for geotechnical purposes with the possible exception of dowels at construction joints as discussed herein. 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 shou ld not exceed 30 times the slab thickness with a maximum spacing of 12.5 feet for the 5-inch and 15 feet for 6-inch or 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 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 wide cut is commonly recommended. A na1Tow joint width of 1/10 to 1/s inch-wide is common for unsealed joints. 7.12.10 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 can 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 3.8.3 of the referenced ACI guide. The structural engineer should provide other alternative recommendations for load transfer. 7.12.11 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 Project No. 02192-52-0 I -21 -January 17, 2018 7.13 7.13.1 7.13.2 7.13.3 7.13.4 7.14 7.14.1 concrete flatwork should be structurally connected to the curbs to help reduce the potential for offsets between the curbs and the flatwork. Site Drainage and Moisture Protection Adequate site drainage is critical to reduce the potential for differential soil movement, erosion and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings. The site should be graded and maintained such that surface drainage is directed away from structures in accordance with 2016 CBC 1804.3 or other applicable standards. In addition, surface drainage should be directed away from the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. Appendix C presents the results of the storm water management investigation. The performance of pavements is highly dependent on providing positive surface drainage away from the edge of the pavement. Ponding of water on or adjacent to the pavement will likely result in pavement distress and subgrade failure. If planter islands are proposed, the perimeter curb should extend at least 12 inches below proposed subgrade elevations. In addition, the surface drainage within the planter should be such that ponding will not occur. Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for prolonged periods of time. 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. Grading, Improvement and Foundation Plan Review Geocon Incorporated should review the final grading, improvement and foundation plans prior to finalization to check their compliance with the recommendations of this report and evaluate the need for additional comments, recommendations, and/or analyses. Project No. 02192-52-0 I -22 -January 17, 2018 LIMITATIONS AND UNIFORMITY OF CONDITIONS 1. The firm that performed the geotechni cal investigation for the project should be retained to provide testing and observation services during construction to provide continuity of geotechnical interpretation and to check that the recommendations presented for geotechnical aspects of site development are incorporated during site grading, construction of improvements, and excavation of foundations. If another geotechnical firm is selected to perform the testing and observation services during construction operations, that firm should prepare a letter indicating their intent to assume the responsibilities of project geotechnical engineer of record. A copy of the letter should be provided to the regulatory agency for their records. In addition, that firm should provide revised recommendations concerning the geotechnical aspects of the proposed development, or a written acknowledgement of their concurrence with the recommendations presented in our report. They should also perform additional analyses deemed necessary to assume the role of Geotechnical Engineer of Record. 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 wi ll 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. 02192-52-01 January 17, 201 8 THE GEOGRAPHICAL INFORMATION MADE AVAILABLE FOR DISPLAY WAS PROVIDED BY GOOGLE EARTH, SUBJECT TO A LICENSING AGREEMENT. THE INFORMATION IS FOR ILLUSTRATIVE PURPOSES ONLY; IT IS NOT INTENDED FOR CLIENT'S USE OR RELIANCE AND SHALL NOT BE REPRODUCED BY CLIENT. CLIENT SHALL INDEMNIFY, DEFEND AND HOLD HARMLESS GEOCON FROM ANY LIABILITY INCURRED AS A RESULT OF SUCH USE OR RELIANCE BY CLIENT. VICINITY MAP G OCON INCORPORATED GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE-SAN DIEGO, CALIFORNIA 921 21-297 4 PHONE 858 558-6900 -FAX 858 558-6159 t N NO SCALE 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA ML /CW DSK/GTYPD DATE 01 -17 -2018 I PROJECT NO.G2192 -52 -01 I FIG. 1 Plotted:01/16/2018 3:15PM I By:JONATHAN WILKINS [ FIie locatlon:Y:\PROJECTS\G2192-52-01 1534 Magnolia Ave\DETAILS\G2192-52-01_Vlclnlty Map.dwg I I ,: ;. ,~ ,: 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 CLIENrS 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. y - 1 j; 0 ' ' ,~ ,. 1/. I I., I ,, /v,' D 1534 MAGNOLIA AVENUE CARSBAD, CALIFORNIA o· 60' 120· SCALE 1•= 60' (On 11x17) GEOCON LEGEND Qudf ........ uNDocuMENTED FILL Qop ........ OLD PARALIC DEPOSITS T-9....._. ,....... ........ APPROX. LOCATION OF TRENCH (P-2) ........ APPROX. LOCATION OF PERCOLATION TEST G::) ........ APPROX. THICKNESS OF UNDOCUMENTED FILL GEOLOGIC MAP GEOCON INCORPORATED u. ~ GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 • 297 4 PHONE 858 558-6900 -FAX 858 558-6159 PROJECT NO. G2 l 92 -52 -01 FIGURE 2 DATE O 1 -1 7 -201 8 Plotted:01118/2018 1:16PM I By:JONATHAN WILKINS I FIie Locatloo:Y:IPROJECTSIG2192-52-01 1534 Magnolia Ave\SHEETSIG2192-52-01 Geologic map.dwg PROPOSED GRADE NOTE: WATER PROOFING PER ARCHITECT 213 H GROUND SURFACE \ RETAINING WALL 2/3 H DRAINAGE PANEL (MIRADRAIN 6000 OR EQUIVALENT) DRAIN SHOULD BE UNIFORMLY SLOPED TO GRAVITY OUTLET OR TO A SUMP WHERE WATER CAN BE REMOVED BY PUMPING MIRAFI 140N FILTER FABRIC (OR EQUIVALENT) OPEN GRADED 1" MAX. AGGREGATE 4" DIA. PERFORATED SCHEDULE 40 PVC PIPE EXTENDED TO APPROVED OUTLET RETAINING WALL PROPOSED GRADE\ 2/3 H GROUND SURFACE WATER PROOFING PER ARCHITECT DRAINAGE PANEL (MIRADRAIN 6000 OR EQUIVALENT) / 4" DIA. SCHEDULE 40 PERFORATED PVC PIPE OR TOTAL DRAIN EXTENDED TO APPROVED OUTLET NO SCALE TYPICAL RETAINING WALL DRAIN DETAIL GEOCON INCORPORAT ED GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 -297 4 PHONE 858 558-6900 -FAX 858 558-6159 ML /CW I I DSK/GTYPD 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA DATE 01 -17 -2018 I PROJECT NO.G2192 -52 -01 I FIG. 4 Plotted:01/16/2018 4:07PM I By:JONATHAN WILKINS I FIie Locatlon:Y:IPROJECTSIG2192-52-01 1534 Magnolia Ave\DETAILS\Typlcal Retaining Wall Drainage Detail (RWDD7A).dwg APPENDIX APPENDIX A FIELD INVESTIGATION We performed our fie ld investigation on September 27, 2017, that consisted of a visual site reconnaissance, excavating 9 exploratory trenches using a rubber-tire backhoe and conducting 2 infiltration tests. The approximate locations of the trenches and infiltration tests are shown on the Geologic Map, Figure 2. As trenching proceeded, we logged and sampled the soi l and geologic conditions encountered. Trench logs and an explanation of the geologic units encountered are presented on figures fol lowing the text in this appendix. We located the trenches in the field using existing reference points. Therefore, actual exploration locations may deviate sli ghtly. We visually classified and logged the soil encountered in the excavations in general accordance with American Society for Testing and Materials (ASTM) practice for Description and Identification of Soils (Visual Manual Procedure D 2488). Project No. G2 I 92-52-0 I January 17, 2018 PROJECT NO. G2192-52-01 DEPTH IN FEET 0 2 4 6 8 SAMPLE NO. Tl-I T l-2 Figure A-1, >-(9 0 -' 0 I I-::; er: w i 0 z :::i 0 er: (9 SOIL CLASS (USCS) SM SM CL SC TRENCH T 1 ELEV. (MSL.) DATE COMPLETED 09-27-2017 ---- EQUIPMENT BACKHOE W/2' BUCKET BY: K. HAASE MATERIAL DESCRIPTION UNDOCUMENTED FILL (Qudl) Loose, d1y Silty, fine to medium SAND: some roots OLD PARALIC DEPOSITS (Qop2-4) Medium dense, damp, light reddish brown, Si lty, fine to medium SAND Dense, moist, olive-brown, fine Sandy, CLAY; iron staining Medium dense, moist, reddish brown to olive brown, Clayey, fine to medium SAND; iron staining -Becomes denser TRENCH TERMINATED AT 9 FEET No groundwater encountered Log of Trench T 1, Page 1 of 1 ~ u.i--:-ZLL wc_j 0 . >-~ er: 0 w ~ er:~ :::i I-I-z C/Jw -1-0 z ~o (.) G2192-52-01.GPJ SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL I] ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED) ~ ... DISTURBED OR BAG SAMPLE ~ ... CHUNK SAMPLE 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. G2192-52-01 Cl'.'. TRENCH T 2 Zw~ ~ w~ >-w Qui-: (9 I-u5---:-Cl'.'.~ DEPTH <l'. SOIL I-Z LL ::J I-0 ~ ~~ui ZlL IN SAMPLE _J w · I-z 0 0 CLASS ELEV. (MSL.) t-en~ 0 C! en w NO. z DATE COMPLETED 09-27-2017 -I-FEET I w-o >-e:. Oz I-::J (USCS) Zen-' ::; 0 W WC!l Cl'.'. ~o Cl'.'. EQUIPMENT BACKHOE W/2' BUCKET BY:K.HAASE Cl..o::~ 0 u (9 MATERIAL DESCRIPTION -0 !t:l SM UNDOCUMENTED FILL (Qudf) Loose, dry, light brown, Silty, fine SAND --- .-I· -t.-l- ·:::.i-:.:;.::r SM OLD PARALIC DEPOSITS (Qop2-4) -2 -~ Medium dense, damp, brown, Silty, fine SAND - ---------------------------------------------------- · .. ·. CL Dense, moist, olive brown, fine Sandy, CLAY --~ - -4 -~ ._ -----~---------------------------------~---1--------- './ SC Dense, moist, reddish brown, Clayey, fine to medium SAND 1(/y. --Ji? t--✓/?--✓./~ . . ). -6 ?3; TRENCH TERMINATED AT 6 FEET No groundwater encountered Figure A-2, G2192-52-01.GPJ Log of Trench T 2, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE II ... STANDARD PENETRATION TEST liiiiJ ... CHUNK SAMPLE ■ ... DRIVE SAMPLE (UNDISTURBED) .:f. ... 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. G2192-52-01 DEPTH IN FEET 0 2 4 6 SAMPLE NO. T3-l Figure A-3, >-0 0 ....J 0 I f--::::; _.-( l 0:: w i 0 z :J 0 0:: (9 SOIL CLASS (USCS) SM SM SM CL TRENCH T 3 ELEV. (MSL.) __ _ DATE COMPLETED 09-27-2017 EQUIPMENT BACKHOE W/2' BUCKET MATERIAL DESCRIPTION UN DOCUMENTED FILL (Qudl) Loose, dry, brown, Silty, fine SAND OLD PARALIC DEPOSITS (Qop2-4) BY: K.HAASE Medium dense, damp, reddish to yellowish brown, Silty, fine to medium SAND Medium dense, moist, brown, Silty, fine to medium SAND Dense, wet, dark reddish brown, fine Sandy, CLAY TRENCH TERMINATED AT 6 FEET No groundwater encountered Log of Trench T 3, Page 1 of 1 w ~ o::~ :J f--f--z C/Jw -f--Oz ::::eo u G2192-52-01.GPJ SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL I] ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED) ~ ... DISTURBED OR BAG SAMPLE liiiJ ... CHUNK SAMPLE _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. G2192-52-01 DEPTH IN FEET -0 -2 - ~ 4 - t-- t-6 SAMPLE NO. T4-l >-('.) 0 __J 0 I I-::; .-·.f·t.--i,: :-.r--r -1:· .. •. . -... .. . . •. . ... -·.·:. 0:: L!J i 0 z ::J 0 0:: ('.) ~-w-~ ~ 14 SOIL CLASS (USCS) SM SM CL ' TRENCH T 4 ELEV. (MSL.) __ _ DATE COMPLETED 09-27-2017 EQUIPMENT BACKHOE W/2' BUCKET MATERIAL DESCRIPTION UNDOCUMENTED FILL (Qudf) Loose, dry, light brown, Silty, fine SAND OLD PARALIC DEPOSITS (Qop2-4) BY: K. HAASE Medium dense, damp, light reddish brown, fine to coarse SAND Dense, moist, olive brown to reddish brown, fine Sandy, CLAY Zw~ ~ Qui-: 1-ZlL Cf)--:, ~~(/) Z LL Wu I-Cf) s: 0 . w-o >-~ ZCfJ--' wwcn 0:: o..O::~ 0 I- ---~---------------------------------~-------SC Dense, moist, olive brown to reddish brown, fine Sandy, CLAY TRENCH TERMINATED AT 6 FEET No groundwater encountered t- LU ~ o::~ ::J I-I-z Cf) L!J -I-Oz ~o u Figure A-4, G2192-52-01.GPJ Log of Trench T 4, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] ... STANDARD PENETRATION TEST ii ... 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. G2192-52-01 DEPTH IN FEET 0 2 4 6 8 10 12 SAMPLE NO. >-('.) 0 -' 0 I I-:::; !!Tl :---i ·-1 :·r t·r:·i-:-:r ---i·.J_-.i·· :j';/ : . _--;<: a:: w i 0 z ::i 0 a:: ('.) SOIL CLASS (USCS) SM SM SC TRENCH T 5 ELEV. (MSL.) __ _ DATE COMPLETED 09-27-2017 EQUIPMENT BACKHOE W/2' BUCKET MATERIAL DESCRIPTION UNDOCUMENTED FILL (Qudt) Loose, dry, light brown, Silty, fine SAND OLD PARALIC DEPOSITS (Qop2-4) BY: K. HAASE Medium dense, moist, dark brown, Silty fine to medium SAND -Becomes brown -Becomes dense Dense, moist, olive gray to reddish brown, Clayey fine to coarse SAND; iron staining TRENCH TERMINATED AT 12 FEET No groundwater encountered Zw~ f w ~ Qui-: f-Z LL (/)--:-a::~ c'i~ui Z LL ::i f-w . f-z f-(/) s: 0(.) (/) w -f-w -o >-~ Oz z (/)-' w WaJ a:: '.20 (La::~ 0 u Figure A-5, G2192-52-01.GPJ Log of Trench T 5, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE IJ ... STANDARD PENETRATION TEST liiiiJ ... 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. G2192-52-01 Cl'. TRENCH T 6 Zw~ ~ >-w Qui-: w "#. (.'.) f-Cl)---:-o::-DEPTH <{ SOIL ~~~ ::, f-0 s: ZlL IN SAMPLE ....J Cl'. f-Cl) wc_j f-z 0 0 CLASS ELEV. (MSL.) f-Cl) s: C/Jw NO. z DATE COMPLETED 09-27-2017 O· -f-FEET I w-o >-~ Oz f-::, (USCS) ZC/J....J Cl'. ~o :i 0 wwco Cl'. EQUIPMENT BACKHOE W/2' BUCKET BY: K. HAASE a..0::-0 u (.'.) MATERIAL DESCRIPTION -0 ).:-:r:r SM UNDOCUMENTED FILL (Qudf) ::·.14:·1 Loose, dry, light brown, Silty, fine SAND --i,...:.1 :.J.. I------1-----------------------------------t----~-------J ·l SM Loose, damp, light reddish brown, Silty fine SAND; little gravel; deleterious J.1 ·1 material -2 -:f (f - .l -l l ~ ·1 --.---r-t --y SM OLD PARALIC DEPOSITS (Qop2-4) it! Medium dense, moist, dark reddish brown, Silty, fine to medium SAND -4 --:---(i:·r --ttt - ·--(1 :·r -6 -. ·-r ·. t- ::::.:::::_(_:·:t:: -Becomes dark brown -----(1 :·r t- !II -Becomes denser, finer grained -8 -t-~---•tJ e----------------------------------------f.-----------~/7 SC Dense, moist, reddish brown, Clayey, fine to medium SAND ---t;.? v/7 t-10 ":.":;,.··.-:· TRENCH TER.MJNATED AT IO FEET No groundwater encountered Figure A-6, G2192-52-01.GPJ Log of Trench T 6, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] ... STANDARD PENETRATION TEST iii;! ... 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. G2192-52-01 DEPTH IN FEET 0 2 4 SAMPLE NO. T7-l >-(.'.) 0 ....J 0 I I-::; 0:: w i 0 z :J 0 0:: (.'.) SOIL CLASS (USCS) SM SM TRENCH T 7 ELEV. (MSL.) ___ DATE COMPLETED 09-27-2017 EQUIPMENT BACKHOE W/2' BUCKET BY:K.HAASE MATERIAL DESCRIPTION UNDOCUMENTED FILL (Qudt) Loose, dry, Light brown, Silty, fine SAND; roots OLD PARALIC DEPOSITS (Qop2-4) Medium dense, damp, light reddish brown, Silty, fine to medium SAND -Becomes dense TRENCH TERMlNATED AT 5 FEET No groundwater encountered Zw ~ ~ w ~ Qui-: 1-Z u.. Cl)--:-o::- ri~ui zu.. :J I- Wc.,j I-z I-Cl)~ Cl) w O · -I-w-o >-e:. Oz ZCl)....J WW CD 0:: ~o 11.0::-0 u Figure A-7, G2192-52-01.GPJ Log of Trench T 7, Page 1 of 1 SAMPLE SYMBOLS □ ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] .. 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. G2192-52-01 cc TRENCH T 8 Zw~ /: >-w Qui-: w ~ I-DEPTH G <: SOIL 1-Z U.. ui--:-cc~ 0 ~ ~;::en zu.. ::, I- IN SAMPLE ....J w . I-z 0 0 CLASS ELEV. (MSL.) DATE COMPLETED 09-27-2017 1-C/J~ DC> (/) w NO. I z w-o >-e:. -I-FEET I-::, (USCS) zC/J....J oz ::::; 0 w w cn cc ~o cc EQUIPMENT BACKHOE W/2' BUCKET BY: K. HAASE o..cc~ 0 u G MATERIAL DESCRIPTION -0 ----r-1-r SM UNDOCUMENTED FILL (Qudt) :J:::t:r Loose, dry, brown, Silty, ftne SAND; roots --ill SM OLD PARALIC DEPOSITS (Qop2-4) Medium dense, damp, light yellowish brown, Silty, fine SAND -2 -- :---r-f:·-y ·-·-r · --:_:_j:.-:(J:_: - --r----r \f:}:j:: -Becomes dense, moist, light reddish brown -4 TRENCH TERMINATED AT 4 FEET No groundwater encountered Figure A-8, G2192-52-01.GPJ Log of Trench T 8, Page 1 of 1 SAMPLE SYMBOLS (;J ... SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE IJ ... 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. G2192-52-01 DEPTH IN FEET 0 2 4 SAMPLE NO. >-(.'.) 0 --' 0 I I-::; Cl'. w i 0 z ::J 0 Cl'. (.'.) SOIL CLASS (USCS) SM SM TRENCH T 9 ELEV. (MSL.) __ _ DATE COMPLETED 09-27-2017 EQUIPMENT BACKHOE W/2' BUCKET MATERIAL DESCRIPTION UNDOCUMENTED FILL (Qudl) Loose, dry, brown, Silty, fine SAND; roots BY: K. HAASE OLD PARALIC DEPOSITS (Qop2) Dense, damp, light reddish to yellowish brown, Silty fine to medium SAND TRENCH TERMINATED AT 4 FEET No groundwater encountered Zw~ ~ w ~ Qu....,: I-Z LL (/) ,--:-Cl'.~ ~~iii Z LL ::J I-w . I-z I-(/) 3:: 0(.) (/)w -I-w-o >-e:.. oz Z(J)--' wwoo Cl'. ~o Cl.a::~ 0 u Figure A-9, G2192-52-01.GPJ Log of Trench T 9, Page 1 of 1 SAMPLE SYMBOLS □ .. SAMPLING UNSUCCESSFUL ~ ... DISTURBED OR BAG SAMPLE I] ... STANDARD PENETRATION TEST ■ ... DRIVE SAMPLE (UNDISTURBED) ~ ... CHUNK SAMPLE 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 accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures. We selected samples to test for maximum density and optimum moisture content, direct shear, expansion potential, water-soluble sulfate content, R-Value and gradation. The results of our laboratory tests are summarized on Tables B-1 through B-V, Figure B-1 and on the trench logs in Appendix A. Sample No. Tl-1 T7-l Sample No. Tl-1 2 T7-1 2 TABLE 8-1 SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Description (Geologic Unit) Maximum Dry Density (pct) Light reddish brown, Silty, fine to medium SAND (Qop) 132.8 Light reddish brown, Silty, fine to medium SAND (Qop) 130.5 TABLE 8-11 Optimum Moisture Content(% dry wt.) 8.1 9.0 SUMMARY OF LABORATORY DIRECT SHEAR TEST RESULTS ASTM D 3080 Dry Density Moisture Content(%) Peak l Ultimate1] Peak [Ultimate1 I Angle of Shear (pct) Initial Final Cohesion (psf) Resistance (degrees) 121.8 6.6 I 3.4 500 [400] 27 [26] 118.6 8.7 13.7 700 [550] 27 [24] 1 Ultimate at end oftest at 0.2-inch deflection. 2 Remolded to a dry density of about 90 percent of the laboratory maximum dry density. Sample No. T3-l T4-I T7-l TABLE B-111 SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Moisture Content(%) Dry Density Expansion 2016 CBC Expansion Before Test After Test (pct) lndex Classification 11.5 23.4 103.8 35 Expansive 8.7 17.2 115.6 18 Non-Expansive 7.8 14.1 117.2 0 Non-Expansive Project No. 02192-52-0 I -B-1 - ASTM Soil Expansion Classification Low Very Low Very Low January 17, 2018 TABLE B-IV SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417 Sa mple No. Water Soluble Sulfate(%) ACI 318-14 Sulfate Class Tl-1 0.032 so T7-1 0.009 so TABLE B-V SUMMARY OF LABORATORY RESISTANCE VALUE (R-VALUE) TEST RESULTS ASTM D 2844 Sample No. Depth (feet) Description (Geologic Unit) R-Value T7-l 2-3 Light reddish brown, Si lty, fi ne to medium SAND (Qop) 44 Project No. G2 l 92-52-0 I -B-2 -January 17, 2018 PROJECT NO. 82192-52-01 GRAVEL SAND COARSE I FINE COARSE MEDIUM FINE SILT OR CLAY U.S. STANDARD SIEVE SIZE 3" 1-1 /2" 3/4" 3/8" 4 f10 116 30 50 20 40 60 1Q0 21 0 100 I I I I I I ~ I 90 II I I I I \ I I I ~ I 80 I I I I I ~~ I I I I I I I t-70 I \ (9 I I I w I I ~ I s 60 I I I >-I I ' I Cl) I I I CI'. I I I w 50 I I ' I z u:::: I I I t-I I I z 40 I", ... w I I u "1 ... CI'. I I I "'::::: w 30 II II II ~ Q_ I I I l~ I I I .... N~ I I I ~ 20 ....... r---II II II r--, r-----; D I I I --~-I I I 10 I' I I I I I I 0 II II II 10 1 0.1 0 .01 0.001 GRAIN SIZE IN MILLIMETERS ASTM D422 SAMPLE DEPTH (ft) CLASSIFICATION NATWC LL PL Pl • T1-1 2.0 SC -Clayey SAND Ill T1-2 6.0 SM -Silty SAND • GRADATION CURVE 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA G2192-52-01.GPJ Figure B-1 GEOCON APPENDIX APPENDIX C STORM WATER MANAGEMENT INVESTIGATION FOR 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA PROJECT NO. G2192-52-01 APPENDIX C STORM WATER MANAGEMENT INVESTIGATION We understand storm water management devices will be used in accordance with the BMP Design Manual currently used by the City of Carl sbad. 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 hydrogeological 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 hydro logic soil groups. If a soil is assigned to a dual hydro logic 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 consist A 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 having a C 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. The property is underlain by natural materials consisting of undocumented fill and Old Paralic Deposits and should be classified as Soil Group D. Table C-11 presents the information from the -C-1 - USDA website for the subject property. The Hydrologic Soil Group Map, provided at the end of this appendix, presents output from the USDA website showing the limits of the soil units. TABLE C-11 USDA WEB SOIL SURVEY -HYDROLOGIC SOIL GROUP Approximate ksAT of Map Unit Hydro logic Most Limiting Map Unit Name Symbol Percentage Soil Group Layer of Property (inches/hour) Chesterton-Urban Land Complex, CgC 83 D 0.00 -0.06 2 to 9 percent slopes Marina Loamy Coarse Sand, MIC 17 B 0.57 -1.42 2 to 9 percent slopes In-Situ Testing 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-III describes the differences in the definitions. TABLE C-111 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 percolation tests within Trenches T-2 and T-3 at the locations shown on the attached Geologic Map, Figure 2. The results of the tests provide parameters regarding the percolation rate and -C-2 - the saturated hydraulic conductivity/infiltration characteristics of on-site soil and geologic units. Table C-IV presents the results of the estimated fie ld saturated hydraulic conductivity and estimated infi ltration rates obtained from the percolation tests. The calculation sheets are attached herein. We used 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-IV FIELD PERMEAMETER INFILTRATION TEST RESULTS Test Depth Geo logic Percolation Field -Saturated C.4-1 Worksheet Test Location Rate Infiltration Rate, Infiltration Rate', (feet) Unit (minutes/inch) ksat (inch/hour) ksat (inch/hour) P-1 (T-2) 6 Qop 187.5 0.07 0.04 P-2 (T-3) 6 Qop 106.0 0.32 0.16 Average: 146.8 0.20 0.10 1 Using a factor of safety of 2. Infiltration categories include full infiltration, partial infiltration and no infiltration. Table C-V presents the commonly accepted definitions of the potential infiltration categories based on the infiltration rates. Infiltration Category Full Infiltration Partial Infiltration No Infiltration (Infeasible) 1 Using a Factor of Safety of 2. Groundwater Elevations TABLE C-V INFILTRATION CATEGORIES Field Infiltration Rate, I (inches/hour) I > 1.0 0.10 <1 <1.0 [<0.10 Factored Infiltration Rate1, I (inches/hour) I > 0.5 0.05 <I < 0.5 I < 0.05 We did not encounter groundwater or seepage during the site investigation. We expect groundwater exists at depths greater than 50 feet below existing grades. -C-3 - New or Existing Utilities Utilities will be constructed within the site boundaries. 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 utilities and instal ling subdrains and/or installing liners. The horizontal and vertical setbacks for infiltration devices should be a minimum of 10 feet and a 1: 1 plane of 1 foot below the closest edge of the deepest adjacent utility, respectively. Existing and Planned Structures Existing residential and roadway structures exist adjacent to the site. Water should not be allowed to infiltrate in areas where it could affect the neighboring properties and existing adjacent structures, improvements and roadway. Mitigation for existing structures consists of not allowing water infiltration within a lateral distance of at least 10 feet from the new or existing foundations. Slopes Hazards Slopes are not currently planned or exist on the property that wou ld be affected by potential infiltration locations. Therefore, infiltration in regards to slope concerns wou ld be considered feasible. Storm Water Evaluation Narrative As discussed herein, the property consists of existing undocumented fill overlying Old Paralic Deposits (Qop). Water should not be allowed to infiltrate into the undocumented or compacted fi ll within the basins as it will all ow for lateral migration to adjacent residences. We evaluated the infiltration rates within the Old Paralic Deposits within the proposed basin areas to help evaluate if infiltration is feasible. We performed the infiltration tests at location where the basins would be practical based on the topography of the property and discussions with the Client. We performed the percolation tests at the lower elevations of the property and adjacent to the existing storm drain system. Our in-place infi ltration tests indicate an average of 0.10 inches/hour (including a factor of safety of 2); therefore, the site is considered feasible for partial infiltration. We do not expect geologic hazards to exist on the property. Therefore, partial infiltration may be considered feasible within the Old Paralic Deposits. 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 impermeable (e .g. High-density polyethylene, HDPE, with a -C-4 - thickness of about 30 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 Schedu le 40 PVC pipe. The subdrains outside of the liner should consist of solid pipe. The penetration of the liners at the subdrains shou ld be properly waterproofed. The subdrains shou ld be connected to a proper outlet. The devices should also be installed in accordance with the manufacturer's recommendations. Liners should be installed on the side walls of the proposed basins in accordance with a partial infi ltration design. Storm Water Standard Worksheets The BMP Design Manual requests the geotechnical engineer complete the Categorization of Infiltration Feasibility Condition (Worksheet C.4-1 or I-8) worksheet information to help evaluate the potential for infiltration on the property. The attached Worksheet C.4-1 presents the completed information for the submittal process. The regional storm water standards also have a worksheet (Worksheet D.5-1 or Form I-9) that helps the project civil engineer estimate the factor of safety based on several factors. Table C-VI describes the suitability assessment input parameters related to the geotechnical engineering aspects for the factor of safety determination. TABLE C-VI 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 localized (i .e. small- infiltration rates. Use of continuous boring log. scale) infiltration testing Direct measurement of 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., lnfiltrometer). infiltration measurement sparse testing with direct Moderate spatial methods. infiltration methods resolution Predominant Soil Si lty and clayey soi ls 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 faci lity bottom -C-5 - Based on our geotechnical investigation and the previous table, Table C-VII 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-VII 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 2 0.50 Depth to Groundwater/ Impervious Layer 0.25 I 0.25 Suitability Assessment Safety Factor, SA = Lp 1.75 1 The project civil engineer should complete Worksheet D.5-l or Form 1-9 using the data on this table. Additional information is required to evaluate the design factor of safety. -C-6 - Part 1 -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 presented in Appendix C.2 and Appendix D. Provide basis: Yes No X Based on the USGS Soil Survey, the property possesses Hydrologic Soil Group D classifications. In addition, we encountered field infiltration rates of: T-2/P-I: 0.07 inches/hour (0.04 with a FOS of2.0) T-3!P-2: 0.32 inches/hour (0.16 with a FOS of2.0) This results in an average infiltration rate of0.20 inches/hour (0.10 with an FOS of2.0). Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 2 Can infiltration 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: X Undocumented fill and Old Paralic Deposits underlie the property. Water that would be allowed to infiltrate could migrate laterally outside of the property limits to the ex isting right-of-ways (located to the south and west) and toward existing and proposed structures (located to the north and east). However, we expect the basins would be setback a sufficient distance from the existing and proposed utilities and structures to help alleviate seepage and underground utility concerns. Additionally, the use of vertical cutoff walls or liners, as recommended herein, would prevent lateral migration of water. The bottom of the basins should expose Old Paralic Deposits. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. -C-7 - Criteria 3 Provide basis: 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 comprehensive evaluation of the factors presented in Appendix C.3. Yes No X We did not encounter groundwater during the drilling operations on the property. We anticipate that groundwater is present at depths of greater than 50 feet. Therefore, infiltration due to groundwater elevations would be considered feasible. Additionally, we understand that contaminated soil or groundwater has not been documented or identified at the property. Therefore, infiltration due to groundwater concerns would be considered feasible. 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 full infiltration would cause water balance issues including change of ephemeral streams or discharge of contaminated water 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 Infiltration 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 Not Full 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. -C-8 - Part 2 -Partial Infiltration vs. No Infiltration Feasibility Screening Criteria 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 X No Based on the USGS Soil Survey, the property possesses Hydrologic Soil Group D classifications. In addition, we encountered field infiltration rates of: T-2/P-l: 0.07 inches/hour (0 .04 with a FOS of2.0) T-3/P-2: 0.32 inches/hour (0.16 with a FOS of2.0) This results in an average infiltration rate of 0.20 inches/hour (0.10 with an FOS of 2.0). 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. X Undocumented fill and Old Paralic Deposits underlie the property. Water that would be allowed to infiltrate could migrate laterally outside of the property limits to the existing right-of-ways (located to the south and west) and toward existing and proposed structures (located to the north and east). However, we expect the basins would be setback a sufficient distance from the existing and proposed utilities and structures to help alleviate seepage and underground utility concerns. Additionally, the use of vertical cutoff walls or liners, as recommended herein, would prevent lateral migration of water. The bottom of the basins should expose Old Paralic Deposits. 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. -C-9 - Criteria 7 Provide basis: 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 did not encounter groundwater during the drilling operations on the property. We anticipate that groundwater is present at depths of greater than 50 feet. Therefore, infiltration due to groundwater elevations would be considered feasible. Additionally, we understand that contaminated soil or groundwater has not been documented or identified at the property. Therefore, infiltration due to groundwater concerns would be considered feasible. 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. 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 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 infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. Partial Infiltration *To be completed using gathered site information and best professional judgment considering the definition ofMEP in the MS4 Permit. Additional testing and/or studies may be required by the City to substantiate findings. -C-IO - ~ GEOCON Excavation Percolation Test Project Name: 1534 Magnolia -----'-----Date: 9/27/2017 Project Number: G2192-52-01 By: JML ---------0 pen -Pit Location: T-2 (P-1) --------- Test Hole Length (in.) 14.0 ---- Test Hole Width (in.) 12.0 _______ ,;.__;_ ____ or Test Hole Dia. (in.) Test Hole Depth (in.) 10.5 Test Hole Area, A, (in.2) 168.0 ----- L:-.t /f..D tJ,,v/1:J.t (Q/A)*60 Depth of Cumulative Wetted Change in Percolation Flow Rate, Infiltration Time, t Reading Water, D /:;,t (min) Time,t /ill (in.) Area,A w,t Volume, Rate Q Rate, / t (min) (in.) (min) (in.2) t:,. V (in .3) (min/in.) (in .3/min) (in./hr) 1 0.0 8.25 15.00 15.00 0.06 595.38 10.50 240.00 0.70 0.07 15.0 8.19 2 0.0 8.50 15.00 30.00 0.01 609.74 1.68 1500.00 0.11 0.01 15.0 8.49 3 0.0 15.0 8.50 8.25 15.00 45.00 0.25 603.50 42.00 60.00 2.80 0.28 4 0.0 8.50 15.00 60.00 0.01 609.74 1.68 1500.00 0.11 0.01 15.0 8.49 5 0.0 8.50 15.00 75.00 0.01 609.74 1.68 1500.00 0.11 0.01 15.0 8.49 6 0.0 8.50 15.00 90.00 0.06 608.38 10.50 240.00 0.70 0.07 15.0 8.44 7 0.0 9.00 15.00 105.00 0.01 635.74 1.68 1500.00 0.11 0.01 15.0 8.99 8 0.0 9.00 15.00 120.00 0.06 634.38 10.50 240.00 0.70 0,07 15.0 8.94 9 0.0 9.00 15.00 135.00 0.01 635.74 1.68 1500.00 0.11 O.Ql 15.0 8.99 10 0.0 15.0 9.00 8.93 15.00 150.00 0.07 634.18 11.76 214.29 0.78 0,07 11 0.0 9.00 15.00 165.00 0.08 633.92 13.44 187.50 0.90 0.08 15.0 8.92 12 0.0 9.25 15.00 180.00 0.05 647.70 8.40 300.00 0.56 0.05 15.0 9.20 13 14 2.00 Qj .... t1I 1.50 cc: -C: ... 0 .s::. 1.00 ·-........ .... t1I C: ... ·-~-0.50 ..:;: E ..... 0.00 ----~ .... -----·-_,,,-----4 . .,_ ______ .. =--•--..... •-----4·.,_ __ _ 0.00 20.00 40.00 60.00 80.00 100.00 120.00 140.00 160.00 180.00 200.00 Time (min) Percolation Rate (Minutes/Inch) = 187.5 0.07 Soil Infiltration Rate (Inches/Hour) ~ GEOCON Excavation Percolation Test Project Name: __ l_S_3_4_M_a....;g;_n_o_li_a __ Project Number: G2192-52-01 ---------Open-Pit Location: T-3 (P-2) ____ ...;._-'---- Test Hole Length (in.) 14.0 ---- Test Hole Width (in.) 12.0 -------------or Test Hole Dia. (in.) Test Hole Depth (in.) Depth of Reading Time, t Water, D h.t (min) (min) (in.) 1 0.0 8.50 15.00 15.0 8.00 2 0.0 8.50 15.00 15.0 8.44 3 0.0 8.50 15.00 15.0 8.38 4 0.0 8.50 15.00 15.0 8.49 5 0.0 8.50 15.00 15.0 8.00 6 0.0 8.19 15.00 15.0 8.00 7 0.0 8.50 15.00 15.0 8.06 8 0.0 8.50 15.00 15.0 8.44 9 0.0 8.75 15.00 15.0 8.44 10 0.0 8.75 15.00 15.0 8.25 11 0.0 8.25 15.00 15.0 8.19 12 13 14 2.00 QI ... Ill 1.50 et:: -C: ... 0 .J::. 1.00 ·-....... ... . Ill C: ... ·-... -0.50 :E .E 0.00 0.00 20.00 40.00 Percolation Rate (Minutes/Inch) Soil Infiltration Rate (Inches/Hour) 11.0 Cumulative Time, t (min) 15.00 30.00 45.00 60.00 75.00 90.00 105.00 120.00 135.00 150.00 165.00 60.00 /ill (in.) 0.50 0.06 0.13 0.01 0.50 0.19 0.44 0.06 0.31 0.50 0.06 80.00 Time (min) Date: 9/27/2017 By: JML Test Hole Area, A, (in. 2) 168.0 ----- 1'.t /1'.D t:i.v/!J.t (Q/A}*60 Wetted Change in Percolation Flow Rate, Infiltration Area,A w,, Volume, Rate Q Rate, / t (in .2) /",. V (in.3) (min/in.) (in.3/min) (in./hr) 597.00 84.00 30.00 5.60 0.56 608.38 10.50 240.00 0.70 0.07 606.75 21.00 120.00 1.40 0.14 609.74 1.68 1500.00 0.11 0.Dl 597.00 84.00 30.00 5.60 0.56 588.88 31.50 80.00 2.10 0.21 598.63 73.50 34.29 4.90 0.49 608.38 10.50 240.00 0.70 0.07 614.88 52.50 48.00 3.50 0.34 610.00 84.00 30.00 5.60 0.55 595.38 10.50 240.00 0.70 O.D7 100.00 120.00 140.00 160.00 180.00 106.0 0.32 t N HYDROLOGIC SOIL SURVEY GEOCON INCORPORATED GEOTECHNICAL ■ ENVIRONMENTAL ■ MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121 -297 4 PHONE 858 558-6900 -FAX 858 558-6159 ML /CW I I DSK/GTYPD 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA DATE 01 -17 -2018 I PROJECT NO.G2192 -52 -01 I FIG. C-1 Plotted:01/17/2018 8:10AM I By:JONATHAN WILKINS I FIie Localion:Y:\PROJECTS\G2192-52-01 1534 Magnolia Ave\DETAILS\G2192-52-01_HydrologlcSollSurvey.dwg APPENDIX APPENDIX D RECOMMENDED GRADING SPECIFICATIONS FOR 1534 MAGNOLIA AVENUE CARLSBAD, CALIFORNIA PROJECT NO. G2192-52-01 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL 1.1 These Recommended Grading Specifications shal l be used in conju nction 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 Consu ltant 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 accompli sh 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 gradin g 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 fo r 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. MA TE RIALS 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 m 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 I ½ inches in diameter shall be removed to a depth of 3 feet below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to provide suitable fill materials. 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 /20 I 5 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 Original Ground .............. 2 ',,~1 ',,,,,, ;-Finish Slope Surface ,, j Remove All Unsuitable Material As Recommended By Consultant Slope To Be Such That Sloughing Or Sliding Does Not Occur ',, .................... ,, ',,,',,,, ,, .................. ,, ',, ----- See Note 2 No Scale DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. 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 m 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 3 feet below finish pad grade and should be compacted at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. 6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over-built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track-walking of slopes, as described in the following paragraph. 6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height intervals. Upon completion, slopes should then be track-walked with a D-8 dozer or similar equipment, such that a dozer track covers all slope surfaces at least twice. 6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: 6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. 6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, rocks or rock fragments up to 10 feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading as specific cases arise and shall be approved by the Consultant prior to placement. 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. 07/20 15 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 m the windrows should be continuously observed by the Consultant. 6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with the following recommendations: 6.3 .1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not develop. The subdrains shall be permanently connected to controlled drainage facilities to control post-construction infiltration of water. 6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock trucks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water trucks traversing in front of the current rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20-ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the 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 and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the results of the plate bearing tests for the soil fill and the rock fill and by evaluating the deflection GI rev. 07/2015 variation w ith 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. 1n 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 fo llowed. 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 subd rains 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 NOTES; 1-~1 DWET£R, SCHtmUlJ! llO PVC PER.FORATm PIPE FOfl FIU.8 INEXC=SS Of 100-f'EET IN OEPTH ORA.PIPE LENGTWOF LOlfGER THAN l!OO FEET. :Z.. -~ OIAMl:TER. so-tEOlA.E 40 FVC PERFOAATED PIPE FOR RU.S LESS niMI 00-FEFr IN DEPTH OR A P<:PE LENGTH 5tlOATER ™AH 600 FEET. BEDROCK NO~ f1'IAI. Z0' o,· AT 0111'\J!T &W,I..Ltl[~T[!) 9 CU81C FffT I FQO't OF 0P9I CIW>EO GRAY£1. ~ BY MIIW"1140NC (OR EOJNAL.Bn') 'l. MllRIC NO SCALE 7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes. GI rev. 07/20 15 TYPICAL STABILITY FILL DETAIL 1-ElCCAYATE IACKCUT AT i 1 NCI.JM,t,llO'i (UNLE&S OT)-~ N0TED~ 7.. !IEOFIITMII nYF1ll. TOOO lA:£1 MO FORJ.u.llt)tW. *Tf'111Al,81 !NOA MINIMUM !1'11 INTOIIIOl"E. 3.-STABUTY Fil. TO IE OOW?OSB> Of PROPEAL Y 4 .. ...0-.NZY ~ 10 APPfiOVYl PREfAOMICATN> CIIIMHt:Y ~ PMB..S (~N G2ICDI OllloQU;Vl'IIL.Nf) $PACED ~TE Y lll F£ET ~ to CEtltelt AHb • F&'I' W!llt. 0..0IIEA IIPt,CIMG tlAY E REOWAm ,_ fiEEf'AOI' Iii~ 0. 5,-,fU'ER MATERIAL TC • 114-M:ti, OPfM-OIW)fl> CRUSHEJ> R00( EHCI..OIEO APPROVED FI.Tl:'R FABAIC (MIIW'l ~ e ..... COUt:CIOR l'<IPC TO 4-INCI~ MINl,ll.llol I.IW,t[l 4, PCRn>RAr • Tl<ICK,WAI.Ul) PVC SCltOlU..C.., OR l!OUIVAl.1!1,T, AVD 111.0!'!n TO MAI< AT Pl!Aa!NT ~ TO N'f"Flf:1V!!:: ounn. 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 VlEW rt,111t SIDE VIEW 7.6 Subdrains that discharge into a natural drainage course or open space area should be provided with a permanent headwall structure. GI rev. 07/2015 TYPICAL HEADWALL DETAIL FRONT VIEW SIDE VIEW rORr -- ro,,r - NO'r1;. H!!AIMN..L 5HOUU)OIJTUT A.T tOf! 0, fill !11.0PE OR IN'TO CONmOUfll SURl'i,()( CRAll'Wlf ,,.. 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. ln 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. I .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 I 0-Pound Hammer and 18-Inch 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. l 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. l 0.2 The Owner is responsible for furnishing a final as-graded so il 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 1, 2016. 2. A3 Development, Conceptual Plan, 6 Lots, 1534 Magnolia Avenue, Carlsbad, California, dated August 16, 2017. 3. ASCE 7-10, Minimum Design Loads for Buildings and Other Structures, Second Printing, April 6, 2011. 4. Boore, D. M., and G. M Atkinson (2008), Ground-Motion Prediction for the Average Horizontal Component of PGA, PGV, and 5%-Damped PSA at Spectral Periods Between 0.01 and 10.0 S, Earthquake Spectra, Volume 24, Issue 1, pages 99-138, February 2008. 5. California Department of Water Resources, Water Data Library. http://www.water.ca.gov/waterdatalibrary. 6. California Geological Survey, Seismic Shaking Hazards in California, Based on the USGS/CGS Probabilistic Seismic Hazards Assessment (PSHA) Model, 2002 (revised April 2003). 10% probability of being exceeded in 50 years. http://redirect.conservation.ca.gov/cgs/rghm/pshamap/pshamain.html 7. 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 JO s, Preprint of version submitted for publication in the NGA Special Volume of Earthquake Spectra, Volume 24, Issue 1, pages 139-171, February 2008. 8. 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. 9. Civil Landworks, Magnolia-Brady Preliminary Tentative Map and Grading Plan, 1534 Magnolia Avenue, Carlsbad, California, dated January 5, 2018. I 0. Geocon Incorporated, Phase I Environmental Site Assessment Report, I 534 Magnolia Avenue, Carlsbad, California, dated October I 0, 2017 (Project No. G2 l 92-62-02). 11. Historical Aerial Photos. http://www.historicaerials.com 12. Kennedy, M. P., and S. S. Tan, Geologic Map of the Oceanside 30 'x60 ' Quadrangle, California, USGS Regional Map Series Map No. 3, Scale 1: 100,000, 2002. 13. Risk Engineering, EZ-FRISK, 2016. 14. Unpublished reports and maps on file with Geocon Incorporated. I 5. United States Geological Survey computer program, US. Seismic Design Maps, http://earthquake.usgs.gov/designmaps/us/application.php. Project No. 02192-52-01 January 17, 2018