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HomeMy WebLinkAboutMS 2018-0006; Breakers View Beach Homes; Preliminary Geotechnical Investigation; 2016-02-11COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOLOGISTS February 11, 2016 Marc Kovens 18 Via Burrone Newport Coast, CA 92657 RE: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Twin Home Development 3648 Carlsbad Boulevard Carlsbad, California Dear Mr. Kovens: In response to your request and in accordance with our Proposal and Agreement dated November 23, 2015 we have performed a preliminary geotechnical investigation on the subject site for the proposed twin home development. The findings of the investigation, laboratory test results and recommendations for foundation design are presented in this report. From a geologic and soils engineering point of view, it is our opinion that the site is suitable for the proposed development, provided the recommendations in this report are implemented during the design and construction phases. However, remedial grading will be necessary for proposed footings and slabs. Additional recommendations may be necessary based on our review of preliminary development plans. If you have any questions, please do not hesitate to contact us at (858) 755-8622. This opportunity to be of service is appreciated. Respectfully submitted, COAST GEOTECHNICAL Mark Burwell, C.E.G. Engineering Geologist Vithaya Singhanet, P .E. Geotechnical Engineer 779 ACADEMY DRIVE * SOLANA BEACH, CALIFORNIA 92075 (858) 755-8622 * FAX (858) 755-9126 PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Twin Home Development 3648 Carlsbad Boulevard Carlsbad, California Prepared For: MarcKovens 18 Via Burrone Newport Coast, CA 92657 February 11, 2016 W.O. P-6541115 Prepared By: COAST GEOTECHNICAL 779 Academy Drive Solana Beach, California 92075 VICINITY MAP INTRODUCTION SITE CONDITIONS PROPOSED DEVELOPMENT SITE INVESTIGATION LABORATORY TESTING GEOLOGIC CONDITIONS CONCLUSIONS RECOMMENDATIONS TABLE OF CONTENTS 4 5 5 5 6 6 8 11 11 A. REMOV ALS/RECOMPACTION 11 B. TEMPORARY SLOPES/EXCAVATION CHARACTERISTICS 12 C. FOUNDATIONS 13 D. SULFATE CONTENT 14 E. SLABS ON GRADE (INTERIOR AND EXTERIOR) 14 F. LATERAL RESISTANCE 15 G. RETAINING WALLS 15 H. DYNAMIC (SEISMIC) LATERAL EARTH PRESSURES 16 I. SETTLEMENT CHARACTERISTICS 17 J. SEISMIC CONSIDERATIONS 17 K. SEISMIC GROUND MOTION DESIGN PARAMETERS 18 L. PRELIMINARY PAVEMENT DESIGN 19 M. UTILITY TRENCH 19 N. DRAINAGE 20 0. GEOTECHNICAL OBSERVATIONS 20 P. PLAN REVIEW 21 LIMITATIONS REFERENCES APPENDIX A APPENDIXB APPENDIXC APPENDICES LABORATORY TEST RESULTS EXPLORATORY BORING LOGS CONCEPT SITE PLAN REGIONAL FAULT MAP SEISMIC DESIGN PARAMETERS DESIGN RESPONSE SPECTRUM GRADING GUIDELINES 21 23 .?;'.< Carl 1/ \\ \~~ 7 ~\ 11 Data use subject to license_ © 2004 Delorme. Topo USA® 5.0. www.delorme.com Topo USA® 5.0 VICINITY MAP ' o¾ /// /? . /ef?-1' ,, /). \ -... -<...<J};'v5/" ~ p~ -------t' t> C '~:> ,, Coast Geotechnical INTRODUCTION February 11, 2016 W.O. P-6541115 Page5 This report presents the results of our geotechnical investigation on the subject property. The purpose of this study is to evaluate the nature and characteristics of the earth materials underlying the property, the engineering properties of the surficial deposits and their influence on the proposed twin home development. SITE CONDITIONS The subject property is located north of Juniper A venue, along the east side of Carlsbad Boulevard, in the city of Carlsbad. The subject property is a relatively level rectangular residential lot. The site includes a single story residence with an attached garage. Access to the rear of the site is via an alley which enters from Juniper A venue. The property is bounded along the north, south and east by developed residential lots. Vegetation includes grass, shrubs and a few trees. Drainage is generally by sheet flow to the east. PROPOSED DEVELOPMENT Concept plans for the development of the site were prepared by Transpacific Architects. It is our understanding that the project will include demolition of the existing structure and the construction of a new two (2) unit twin home structure. The structure will be constructed slightly below existing Coast Geotechnical February 11, 2016 W.O. P-6541115 Page6 grade. It is anticipated that excavation of approximately 1. 0 vertical feet will be necessary to achieve pad grade. SITE INVESTIGATION Two (2) exploratory borings were drilled to a maximum depth of20 feet with a tri-pod hollow-stem drill rig. Earth materials encountered were visually classified and logged by our field engineering geologist. Standard penetration tests (SPT) were performed in the hollow-stem borings. Undisturbed, representative samples of earth materials were obtained at selected intervals. Samples were obtained by driving a thin walled steel sampler into the desired strata. The samples are retained in brass rings of 2.5 inches outside diameter and 1.0 inches in height. The central portion of the sample is retained in close fitting, waterproof containers and transported to our laboratory for testing and analysis. LABORATORY TESTING Classification The field classification was verified through laboratory examination, in accordance with the Unified Soil Classification System. The final classification is shown on the enclosed Exploratory Logs. Moisture/Density The field moisture content and dry unit weight were determined for each of the undisturbed soil Coast Geotechnical February 11, 2016 W.O. P-6541115 Page7 samples. This information is useful in providing a gross picture of the soil consistency or variation among exploratory excavations. The dry unit weight was determined in pounds per cubic foot. The field moisture content was determined as a percentage of the dry unit weight. Both are shown on the enclosed Laboratory Tests Results and Exploratory Logs. Maximum Dry Density and Optimum Moisture Content The maximum dry density and optimum moisture content were determined for selected samples of earth materials taken from the site. The laboratory standard tests were in accordance with ASTM D-1557-91. The results of the tests are presented in the Laboratory Test Results. Shear Test Shear tests were performed in a strain-control type direct shear machine. The rate of deformation was approximately O. 025 inches per minute. Each sample was sheared under varying confining loads in order to determine the Coulomb shear strength parameters, cohesion and angle of internal friction. Samples were tested in a saturated condition. The results are presented in the Laboratory Test Results. Sulfate Test A sulfate test was performed on a selected sample in accordance with California Test Method ( CTM) 417. The results are presented in the Lab Test Results. Coast Geotechnical GEOLOGIC CONDITIONS February 11, 2016 W.O. P-6541115 Page8 The subject property is located in the Coastal Plains Physiographic Province of San Diego. The property is underlain at relatively shallow depths by Pleistocene terrace deposits. The terrace deposits are underlain at depth by Eocene-age sedimentary rocks which have commonly been designated as the Santiago Formation on published geologic maps. The terrace deposits are covered by thin soil deposits and, in part, by minor fill deposits. A brief description of the earth materials encountered on the site follows. Artificial Fill (at) No evidence of significant fill deposits were observed on the site. However, minor fill deposits, up to approximately 1.0 foot, are present along the perimeter of the residence. The fill is composed of locally derived silty, fine and medium-grained sand. The rear parking area is covered by approximately 4.0 inches of gravel. Soil (Os) Approximately 8.0 inches of soil was encountered in the exploratory borings. The soil is composed of brown silty fine and medium-grained sand. The soil is generally slightly moist and loose. The contact with the underlying terrace deposits is gradational. Coast Geotechnical Terrace Deposits (Qt) February 11, 2016 W.O. P-6541115 Page9 Underlying the surficial materials, poorly consolidated Pleistocene terrace deposits are present. The terrace deposits are composed of tan to reddish brown, fine and medium-grained sand and are generally moist to very moist and weathered in the upper 2. 0 to 3. 0 feet. Below the weathered zone, the terrace deposits are in a medium dense to dense condition. The terrace deposits generally exhibit little or no cohesion. Regionally, the Pleistocene sands are considered flat-lying and are underlain at depth by Eocene-age sedimentary rock units. Medium-dense to dense terrace deposits are considered suitable for the support of foundations and fills. Expansive Soil Based on our experience in the area and previous laboratory testing of selected samples, the fill deposits, residual soil and Pleistocene sands reflect an expansion potential in the very low range. Groundwater No groundwater was observed to the depth explored. However, it should be noted that seepage problems can develop after completion of construction. These seepage problems most often result from drainage alterations, landscaping and over-irrigation. In the event that seepage or saturated ground does occur, it has been our experience that they are most effectively handled on an individual basis. Coast Geotechnical Tectonic Setting February 11, 2016 W.O. P-6541115 Page 10 The site is located within the seismically active southern California region which is generally characterized by northwest trending Quaternary-age fault zones. Several of these fault zones and fault segments are classified as active by the California Division of Mines and Geology (Alquist- Priolo Earthquake Fault Zoning Act). Based on a review of published geologic maps, no known faults transverse the site. The nearest active fault is the offshore Rose Canyon Fault Zone located approximately 4.3 miles west of the site. It should be noted that the Rose Canyon Fault is not a continuous, well-defined feature but rather a zone of right stepping en echelon faults. The complex series of faults has been referred to as the Offshore Zone of Deformation (Woodward-Clyde, 1979) and is not fully understood. Several studies suggest that the Newport-Inglewood and the Rose Canyon faults are a continuous zone of en echelon faults (Treiman, 1984). Further studies along the complex offshore zone of faulting may indicate a potentially greater seismic risk than current data suggests. Other faults which could affect the site include the Coronado Bank, Elsinore, San Jacinto and San Andreas Faults. The proximity of major faults to the site and site parameters are shown on the enclosed Seismic Design Parameters. Liguefaction Potential Liquefaction is a process by which a sand mass loses its shearing strength completely and flows. The temporary transformation of the material into a fluid mass is often associated with ground motion resulting from an earthquake. Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 11 Owing to the medium-dense nature of the Pleistocene terrace deposits and the anticipated depth to groundwater, the potential for seismically induced liquefaction and soil instability is considered low. CONCLUSIONS 1) The subject property is located in an area that is relatively free of potential geologic hazards such as landsliding, high groundwater tables, liquefaction and seismically induced subsidence. 2) The existing fill, soil and weathered terrace deposits encountered on the site are unsuitable for the support of proposed footings and concrete flatwork in their present condition. These surficial deposits should be removed and replaced as properly compacted fill for the support of foundations, concrete flatwork and exterior improvements. 3) The proposed development should not adversely affect the adjacent properties provided the recommendations of this report are implemented during the design and construction phases. RECOMMENDATIONS Removals/Recompaction The existing fill, soil and weathered terrace deposits in the building pad should be removed and replaced as properly compacted fill. All fill should be keyed and benched into the underlying terrace Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 12 deposits. Removals should extend a minimum of 5.0 feet beyond the building footprint. A 1: 1 (horizontal to vertical) temporary slope should be graded along the property lines. Fill should be benched into the temporary slope. Additional recommendations will be necessary based on proposed plans and actual field conditions encountered during grading. The depth of removals are anticipated to be on the orderof3.5 feet. However, a minimum of 1.5 feet of fill should underlie footings. Most of the existing earth deposits are generally suitable for reuse, provided they are cleared of all vegetation, debris and thoroughly mixed. Prior to placement of fill, the base of the removal should be observed by a representative of this firm. Additional overexcavation and recommendations may be necessary at that time. The exposed bottom should be scarified to a minimum depth of 6.0 inches, moistened as required and compacted to a minimum of 90 percent of the laboratory maximum dry density. Fill should be placed in 6.0 to 8.0 inch lifts, moistened to approximately 1.0 -2.0 percent above optimum moisture content and compacted to a minimum of 90 percent of the laboratory maximum dry density. Fill, soil and weathered terrace deposits in areas of proposed concrete flatwork and driveways should be removed and replaced as properly compacted fill. Imported fill, if necessary, should consist of non-expansive granular deposits approved by the geotechnical engineer. Temporary Slopes/Excavation Characteristics Temporary excavations, up to 5.0 feet, should be trimmed to a gradient of 1: 1 (horizontal to vertical) or less depending upon conditions encountered during grading. The terrace deposits exhibit little Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 13 or no cohesion and some degree of sloughing may occur along the temporary slope face. Based on the concept plans, shoring is not anticipated. Based on our experience in the area, the Pleistocene terrace deposits are easily rippable with conventional medium to heavy earth moving equipment in good working order. Foundations The following design parameters are based on footings founded into non-expansive approved compacted fill deposits or competent terrace deposits. Footings should not span cut/fill transitions. Footings for the proposed structure should be a minimum of 12 inches and 15 inches wide and founded a minimum of 12 inches and 18 inches below the lower most adjacent sub grade at the time of foundation construction for single-story and two-story structures, respectively. A 12 inch by 12 inch grade beam or footing should be placed across the garage opening. Footings should be reinforced with a minimum of four No. 4 bars, two along the top of the footing and two along the base. Footing recommendations provided herein are based upon underlying soil conditions and are not intended to be in lieu of the project structural engineer's design. For design purposes, an allowable bearing value of 1700 pounds per square foot and 2000 pounds per square foot may be used for foundations at the recommended footing depths for single and two story structures, respectively. Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 14 For footings deeper than 18 inches, the bearing value may be increased by 20 percent for each additional foot of embedment and 10 percent for each additional foot of width of footing to a maximum of 3500 pounds per square foot. The bearing value may be increased by one-third for short durations of loading, which includes the effects of wind and seismic forces. The bearing value indicated above is for the total dead and frequently applied live loads. This value may be increased by 33 percent for short durations of loading, including the effects of wind and seismic forces. Sulfate Content Based on selective testing, the soluble sulfate content is negligible. Slabs on Grade (Interior and Exterior) Slabs on grade should be a minimum of 5 .0 inches thick and reinforced in both directions with No. 3 bars placed 18 inches on center in both directions. Exterior slabs on grade should be a minimum of 4.0 inches thick and reinforced with No. 3 placed 18 inches on center in both directions. The slab should be underlain by a minimum 2.0-inch coarse sand blanket (S.E. greater than 30). Where moisture sensitive floors are used, a minimum 10.0-mil Visqueen, Stego or equivalent moisture barrier should be placed over the sand blanket and covered by an additional two inches of sand (S .E. greater than 30). Utility trenches underlying the slab may be backfilled with on-site materials, compacted to a minimum of 90 percent of the laboratory maximum dry density. Slabs including Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 15 exterior concrete flatwork should be reinforced as indicated above and provided with saw cuts/expansion joints, as recommended by the project structural engineer. All slabs should be cast over dense compacted subgrades. Exterior slabs should be provided with weakened plane joints at frequent intervals in accordance with the American Concrete Institute (ACI) guidelines. Our experience indicates that the use of reinforcement in slabs and foundations can reduce the potential for drying and shrinkage cracking. However, some minor cracking is considered normal and should be expected as the concrete cures. Moisture barriers can retard but not eliminate moisture vapor movement from the underlying soils up through the slab. Lateral Resistance Resistance to lateral load may be provided by friction acting at the base of foundations and by passive earth pressure. A coefficient of friction of 0.25 may be used with dead-load forces. A passive earth pressure of 200 pounds per square foot, per foot of depth of fill or terrace deposits penetrated to a maximum of 2500 pounds per square foot may be used. Retaining Walls Cantilever walls (yielding) retaining nonexpansive granular soils may be designed for an active- equivalent fluid pressure of 38 pounds per cubic foot for a level surcharge. Restrained walls (nonyielding) should be designed for an "at-rest" equivalent fluid pressure of 60 pounds per cubic foot. Wall footings should be designed in accordance with the foundation design recommendations. Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 16 All retaining walls should be provided with an adequate backdrainage system. A geocomposite blanket drain such as Miradrain 6000 or equivalent is recommended behind walls. The soil parameters assume a level nonexpansive select granular backfill compacted to a minimum of 90 percent of the laboratory maximum dry density. Dynamic (Seismic) Lateral Earth Pressures For proposed restrained walls (non-yielding), potential seismic loading should be considered. For smooth rigid walls Wood (1973) expressed the dynamic thrust in the following form: t..Pe = kh YH2 (non-yielding) where kh is ½ peak ground acceleration equal to 50 percent of the design spectral response acceleration coefficient (Sds) divided by 2.5 per C.B.C. (2007), Y is equal to the unit weight of backfill and H is equal to the height of the wall. The pressure diagram for this dynamic component can be approximated as an inverted trapezoid with stress decreasing with depth. The point of application of the dynamic thrust is at a height of 0.6 above the base of the wall. The magnitude of the resultant is : t..Pe = 20.1 H2 (non-yielding) This dynamic component should be added to the at-rest static pressure for seismic loading conditions. Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 17 For cantilever walls (yielding), Seed and Whitman (1970) developed the dynamic thrust as: t.Pe = 3/8 kh YH2 (yielding) The pressure diagram for this dynamic component can be approximated as an inverted trapezoid with stress decreasing with depth and the resultant at a height of 0.6 above the base of the wall. The magnitude of the resultant is: t.Pe = 7.5 H2 (yielding) This dynamic component should be added to the static pressure for seismic loading conditions. Settlement Characteristics Estimated total and differential settlement over a horizontal distance of 3 0 feet is expected to be on the order of 1.0 inch and 3/4 inch, respectively. It should also be noted that long term secondary settlement due to irrigation and loads imposed by structures is anticipated to be 1/4 inch. Seismic Considerations Although the likelihood of ground rupture on the site is remote, the property will be exposed to moderate to high levels of ground motion resulting from the release of energy should an earthquake occur along the numerous known and unknown faults in the region. The Rose Canyon Fault Zone located approximately 4.3 miles west of the property is the nearest known active fault and is considered the design earthquake for the site. Coast Geotechnical Seismic Ground Motion Design Parameters February 11, 2016 W.O. P-6541115 Page 18 Seismic ground motion values were determined as part of this investigation in accordance with Chapter 16, Section 1613 of the 2013 California Building Code (CBC) and ASCE 7-10 Standard using the web-based United States Geological Survey (USGS) ground motion calculator. Generated results including the Mapped (Ss, Si), Risk-Targeted Maximum Considered Earthquake (MCER) adjusted for site Class effects (SMs, SMt) and Design (Sos, Sm) Spectral Acceleration Parameters as well as Site Coefficients (Fa, Fv) for short periods (0.20 second) and I-second period, Site Class, Design and Risk-Targeted Maximum Considered Earthquake (MCER) Response Spectrums, Mapped Maximum Considered Geometric Mean (MCEa) Peak Ground Acceleration adjusted for Site Class effects (PGAM) and Seismic Design Category based on Risk Category and the severity of the design earthquake ground motion at the site are summarized in the enclosed Appendix A. Site Class D Seismic Design Category D Ss: 1.161 Sl: 0.445 SMs: 1.203 SMl: 0.692 SDs: 0.802 SDl: 0.461 Fa: 1.035 Fv: 1.555 Coast Geotechnical Preliminary Pavement Design February 11, 2016 W.O. P-6541115 Page 19 The following preliminary pavement section is recommended for proposed driveways: 4.0 inches of asphaltic concrete on 6.0 inches of select base (Class 2) on 12 inches of compacted subgrade soils or 5.5 inches of concrete on 12 inches of compacted subgrade soils Subgrade soils should be compacted to the thickness indicated in the structural section and left in a condition to receive base materials. Class 2 base materials should have a minimum R-value of 78 and a minimum sand equivalent of 30. Subgrade soils and base materials should be compacted to a minimum of95 percent of their laboratory maximum dry density. Concrete should be reinforced with No. 3 bars placed 18 inches on center in both directions. It is suggested that concrete be underlain by a minimum of 4.0 inches of Class 2 base. The pavement section should be protected from water sources. Migration of water into subgrade deposits and base materials could result in pavement failure. Utility Trench We recommend that all utilities be bedded in clean sand (S.E. greater than 30) to at least one foot above the top of the conduit. The bedding should be moistened and tamped in place to fill all the voids around the conduit. Imported or on-site granular material compacted to at least 90 percent relative compaction may be utilized for backfill above the bedding. Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 20 The invert of subsurface utility excavations paralleling footings should be located above the zone of influence of these adjacent footings. This zone of influence is defined as the area below a 45 degree plane projected down from the nearest bottom edge of an adjacent footing. This can be accomplished by either deepening the footing, raising the invert elevation of the utility, or moving the utility or the footing away from one another. Drainage Specific drainage patterns should be designed by the project architect or engineer. However, in general, pad water should be directed away from foundations. Roof water should be collected and transferred to hardscape. Vegetation adjacent to foundations should be avoided. If vegetation in these areas is desired, sealed planter boxes or drought resistant plants should be considered. Other alternatives may be available, however, the intent is to reduce moisture from migrating into foundation subsoils. Irrigation should be limited to that amount necessary to sustain plant life. All drainage systems should be inspected and cleaned annually, prior to winter rains. Geotechnical Observations Structural footing excavations should be observed by a representative of this firm, prior to the placement of steel and forms. All fill should be placed while a representative of the geotechnical engineer is present to observe and test. Coast Geotechnical Plan Review February 11, 2016 W.O. P-6541115 Page21 Only concept plans were available at the time of this study. A copy of the preliminary plans should be submitted to this office for review prior to the initiation of construction. Additional recommendations may be necessary at that time. LIMITATIONS This report is presented with the provision that it is the responsibility of the owner or the owner's representative to bring the information and recommendations given herein to the attention of the project's architects and/or engineers so that they may be incorporated into plans. If conditions encountered during construction appear to differ from those described in this report, our office should be notified so that we may consider whether modifications are needed. No responsibility for construction compliance with design concepts, specifications or recommendations given in this report is assumed unless on-site review is performed during the course of construction. The subsurface conditions, excavation characteristics and geologic structure described herein are based on individual exploratory excavations made on the subject property. The subsurface conditions, excavation characteristics and geologic structure discussed should in no way be construed to reflect any variations which may occur among the exploratory excavations. Please note that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature and other factors not evident at the time measurements were made and reported herein. Coast Geotechnical assumes no responsibility for variations which may occur across the site. Coast Geotechnical February 11, 2016 W.O. P-6541115 Page 22 The conclusions and recommendations of this report apply as of the current date. In time, however, changes can occur on a property whether caused by acts of man or nature on this or adjoining properties. Additionally, changes in professional standards may be brought about by legislation or the expansion of knowledge. Consequently, the conclusions and recommendations of this report may be rendered wholly or partially invalid by events beyond our control. This report is therefore subject to review and should not be relied upon after the passage of two years. The professional judgments presented herein are founded partly on our assessment of the technical data gathered, partly on our understanding of the proposed construction and partly on our general experience in the geotechnical field. However, in no respect do we guarantee the outcome of the project. This study has been provided solely for the benefit of the client and is in no way intended to benefit or extend any right or interest to any third party. This study is not to be used on other projects or extensions to this project except by agreement in writing with Coast Geotechnical. Coast Geotechnical REFERENCES February 11, 2016 W.O. P-6541115 Page 23 1. California Building Standards Commission, January 1, 2013, 2013 California Building Code, California Code of Regulations. 2. Petersen, Mark D. and others (DMG), Frankel, Arthur D. and others (USGS), 1996, Probabilistic Seismic Hazard Assessment for the State of California, California Division of Mines and Geology OFR 96-08, United States Geological Survey OFR 96-706. 3. Treiman, J.A., 1984, The Rose Canyon Fault Zone, A Review and Analysis, California Division of Mines and Geology. 4. United States Geological Survey, 2007, Seismic Hazard Curves and Uniform Hazard Response Spectra, Volume 5.0.8. MAPS/ AERIAL PHOTOGRAPHS 1. California Division of Mines and Geology, 1994, Fault Activity Map of California, Scale 1 "=750,000'. 2. Geologic Map of the Oceanside, San Luis Rey and San Marcos 7.5' Quadrangles, 1996, DMG Open File Report 96-02. 3. Tan, S.S., and Giffen, D.G., 1995, Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, Plate 35A, Open-File Report 95-04, Map Scale 1:24,000. 4. Transpacific Architects, 2016, Concept Plans, Breaker View Beach House, 3648 Carlsbad Boulevard, Carlsbad, California, Scale 1/4"=1'. 5. U.S.G.S., 7.5 Minute Quadrangle Topographic Map, Digitized, Scale Variable. APPENDIX A LABORATORY TEST RESULTS TABLE I Maximum Dry Density and Optimum Moisture Content (Laboratory Standard ASTM D-1557-91) Sample Location B-1@ 1.5'-3.0' Max. Dry Density (pcf) 127.8 TABLE II Optimum Moisture Content 9.2 Field Dry Density and Moisture Content Sample Location B-1 @ 3.0' B-1 @ 10.0' B-1 @ 15.0' B-2 @ 5.0' B-2 @ 8.0' B-2 @ 16.5' Sample Location B-1@ l.5'-3.0' (Remolded) Field Dry Density (pcf) 101. 3 106.2 109.7 101.7 117.0 108.7 TABLE III Direct Shear Test Results Angle of Internal Friction 0 29 Degrees (Page 1 of 2) Field Moisture Content 1 11. 8 5.9 5.2 7.1 7.0 3.5 Apparent Cohesion (psf) 37 TABLE V Water Soluble Sulfate California Test 417 Sample B-1@ 1.5'-3.0' (Page 2 of 2) Sulfate Content (%) 0.034 (negligible) P-6541115 LOG OF EXPLORATORY BORING NO. 1 DRILL RIG: TRI-POD HOLLOW-STEM AUGER BORING DIAMETER: 6.0" SURFACE ELEV.: 56' (Approximate) ,-., ';;?_ 0 '--' i:i::: f-< ~ 5 ffi w C f-< >"-◄ Q ~ i:i::: H 5 f-< ~ f-< >, 5 w f-< ;;: C'.J f-< u u w 0 H $ Cl) ~ --< ....l ....l ffi ~ 0 w u w -----Ci f-< u ....:I ::r:: ~ >, Cl) Cl) ~ ~ f-< 0 §3 0.. ~ cl :::E ....:I --< w Cl) P'.l Cl) Ci C'.J 101.3 11.8 7 '"O (!) i:; (!) ti) ..0 0 .... (!) 106.2 5.9 ~ ~ '"O § 0 0 34 0 z 109.7 5.2 57 43 SHEET I OF I ,-., Cl) u Cl) 2, cri Cl) --< ....l u ....l 0 Cl) SM SP PROJECT NO. P-6541115 DATE DRILLED: 01-12-16 LOGGED BY: MB GEOLOGIC DESCRIPTION Gravel Surface for Parkin SOIL(Qs): Bm. fine and medium-grained sand, silty TERRACE DEPOSITS (Qt): Tan to Reddish bm., fine and med.-graine weathered in upper 3.0' to 4.0' Loose becomes increasingly dense with depth Dense From 14', apparent increase in density V. Dense Dense End of Boring @ 20' COAST GEOTECHNICAL LOG OF EXPLORATORY BORING NO. 2 DRILL RIG: TRI-POD HOLLOW-STEM AUGER BORING DIAMETER: 6.0" SURFACE ELEV.: 56' (Approximate) ,,..__ ~ " '--' p,:: f-, ....; 5 ffi r.il C f-, ..... <) f-, < p,:: -8 ~ r.il f-, >, 5 0... ;;: r.il f-, C!:) f-, u u s r.il 0 -[.fl ~ < ....:l ....:l ffi ~ 0 r.il u r.il -~ f-, u ....:l ::r::: ~ >, [.fl [.fl ~ ~ f-, c3 0 § 0 0... ~ r.il ~ [.fl ....:l < ~ C!:) iXI [.fl 101.7 7.1 21 "d (I) :, 117.0 7.0 t-, (I) "' .0 0 t-, 25 (I) 1ii ;$ "d § 0 0 0 z 108.7 3.5 58 SHEET I OF I ,,..__ [.fl u [.fl e, <:Ji [.fl < ....:l u ....:l -0 [.fl SM SP PROJECT NO. P-6541115 DATE DRILLED: 01-12-16 LOGGED BY: MB GEOLOGIC DESCRIPTION Gravel Surface for Parkin SOIL(Qs): Brn. fine and medium-grained sand, silty TERRACE DEPOSITS (Qt): Tan to Reddish brn., fine and med.-graine weathered in upper 3.0' to 4.0' Med. Dense Med. Dense becomes increasingly dense with depth From 14', apparent increase in density V. Dense End of Boring @ 20' COAST GEOTECHNICAL i _---,~-Ml";"'' ' : ' I ' ' I ,/ 1 -'-.I I : -.,', Jf : : : : : : : : i !t~~"'ii,.'§2~,... cc~-"~•c~s,;cf:~~'-"::''i,f~i """'""'-~",---~s:-s, 111 I ,, ,_A.' ~::;J:;~;l~~G· .,, ·e: I ," ' I I , i i: -8 l ~\; : __ / ~ : ~-, ·-~ ~----;i: 8 -2: I ' I ~• --I ;J (3•1 -, ,~-------L -. '··j. .-,, I w D 1:.--·-·-·-·-·-·+-·-·-· • I • --'l . II ~. / r:!f-----__!__ ------,, ··:,:!~< . .,1. r··''fT'; f>_ .. :;, : ·--~-. r:- .' c'"! -~--. PORT ! ! ORJVEWA·~ I : I ~-··--=m -~-~-~--~,-1=-1======~ I D . ~:' '. I· """'l~1:eAJ..CONY ' GEOLOGIC UNITS af ARTIFICIAL FILL Qs SOIL Qt TERRACE DEPOSITS .1, :2,: "·· ::4: CONCEPT-SITE PLAN SCALE: Reduced LEGEND ♦ BORING LOCATION (approx.) I• ; ••0LE·-~··-I . :; '.'\-.. ~o 'QQ ~ ~ COAST GEOTECHNICAL P-654 I 115 C.,11) -... ~u c.,W "' ... a. -.,, ::c zU "'at: at:"' ... ~ ci ~ "' C C( "' '.'.l "' C( u "' ; g ~ ~ .;, I,.,/ rJj :::: ::; ;;;;) ~ "'~; "'!= -, ~,~ ~i c:, < "fo. C? I,.,/ L.I.J ~ = = ... = C u z, !~ 5;; Cl ::::3: !. :ii : ~ 0 ~ >-• < ~i '§ i-. ~ --~: i w •• "' z 0. ;i ~ ;; ro " < u 2 ~ I j I w J ci ~I ~ ~ □ < : <.: 0 C ~ < "C ¢ C u -: ~ ~ u ~.Q._1111/11•1::" 15.01 A-2.1 APPENDIXB CALIFORNIA FAULT MAP KOVENS 150 100 50 0 -50 -100 -150 -200 -250 -300 -350 -400 -450 -500 50 100 150 200 250 300 350 400 450 500 550 600 Design Maps Summary Report http:// ehp 1-earthquake.cr.usgs.gov / designmaps/us/summary. php?templa ... 1 of 1 ■USGS Design Maps Summary Report User-Specified Input Report Title KOVENS Mon January 25, 2016 19:57:38 UTC Building Code Reference Document ASCE 7-10 Standard (which utilizes USGS hazard data available in 2008) Site Coordinates 33.15°N, 117.347°W Site Soil Classification Site Class D -"Stiff Soil" Risk Category I/II/III USGS-Provided Output 55 = 1.161 g 51 = 0.445 g SMs = 1.203 g SM1 = 0.692 g Sos= 0.802 g 501 = 0.461 g For information on how the 55 and 51 values above have been calculated from probabilistic (risk-targeted) and deterministic ground motions in the direction of maximum horizontal response, please return to the application and select the "2009 NEHRP" building code reference document. 'ii -Ill C/1 MCE1t Response Spectrum 1.43 1.30 1.17 1.04 0.91 0.79 O.GS 0.52 0.39 0.2' o.u 0.00 ,..___. ___________ __,_ ___ ,__--, 0.00 0.20 0.40 O.GO 0.80 1.00 1.20 1.40 1.60 1.80 2.00 Period, T ( sec) 'i, -Ill C/1 0.!10 0.81 o.n 0.63 0.54 0.45 0.36 0.27 0.18 o.o, Design Response Spectrum o. 00 ..___,~--+--+--->--+--+-----+--+---t o.oo 0.20 o.,o 0.60 o.so 1.00 1.20 1.40 1.,0 um 2.00 Period, T ( sec) For PGAM, TL, c.5, and c., values, please view the detailed report. Although this information is a product of the U.S. Geological Survey, we provide no warranty, expressed or implied, as to the accuracy of the data contained therein. This tool is not a substitute for technical subject-matter knowledge. 1/25/2016 12:00 PM Design Maps Detailed Report http://ehp1-earthquake.cr.usgs.gov/ designmaps/us/report.php?template ... 1 of6 IIUSGS Design Maps Detailed Report ASCE 7-10 Standard (33.15°N, 117 .347°W) Site Class D -"Stiff Soil", Risk Category I/II/III Section 11.4.1 -Mapped Acceleration Parameters Note: Ground motion values provided below are for the direction of maximum horizontal spectral response acceleration. They have been converted from corresponding geometric mean ground motions computed by the USGS by applying factors of 1.1 (to obtain S5) and 1.3 (to obtain S1). Maps in the 2010 ASCE-7 Standard are provided for Site Class B. Adjustments for other Site Classes are made, as needed, in Section 11.4.3. From Figure 22-1 £11 Ss = 1.161 g From Figure 22-2 r21 51 = 0.445 g Section 11.4.2 -Site Class The authority having jurisdiction (not the USGS), site-specific geotechnical data, and/or the default has classified the site as Site Class D, based on the site soil properties in accordance with Chapter 20. Table 20.3-1 Site Classification Site Class A. Hard Rock B. Rock C. Very dense soil and soft rock D. Stiff Soil E. Soft clay soil F. Soils requiring site response analysis in accordance with Section 21.1 >5,000 ft/s 2,500 to 5,000 ft/s 1,200 to 2,500 ft/s 600 to 1,200 ft/s <600 ft/s Nor Heh N/A ... ~~--~ N/A >50 15 to 50 <15 -s. N/A N/A >2,000 psf 1,000 to 2,000 psf <1,000 psf Any profile with more than 10 ft of soil having the characteristics: • Plasticity index PI> 20, • Moisture content w ~ 40%, and • Undrained shear strength Su < 500 psf -----------See Section 20.3.1 For SI: lft/s = 0.3048 m/s 11b/ft2 = 0.0479 kN/m2 1/25/2016 12:06 PM Design Maps Detailed Report http://ehpl-earthquake.cr.usgs.gov/designmaps/us/report.php?template ... 2 of6 Section 11.4.3 -Site Coefficients and Risk-Targeted Maximum Considered Earthquake (M~ER) Spectral Response Acceleration Parameters Site Class A B C D E F Site Class A B C D E F Table 11.4-1: Site Coefficient F. Mapped MCE R Spectral Response Acceleration Parameter at Short Period S5 :5 0.25 S5 = 0.50 S5 = 0.75 Ss = 1.00 0.8 0.8 0.8 0.8 1.0 1.0 1.0 1.0 1.2 1.2 1.1 1.0 1.6 1.4 1.2 1.1 2.5 1.7 1.2 0.9 See Section 11.4. 7 of ASCE 7 Note: Use straight-line interpolation for intermediate values of S5 For Site Class= D and S5 = 1.161 g, F. = 1.035 Table 11.4-2: Site Coefficient F. S5 ,':'. 1.25 0.8 1.0 1.0 1.0 0.9 Mapped MCE R Spectral Response Acceleration Parameter at 1-s Period S1 :5 0.10 S1 = 0.20 S1 = 0.30 S1 = 0.40 S1 ,:'. 0.50 0.8 0.8 0.8 0.8 0.8 1.0 1.0 1.0 1.0 1.0 1. 7 1.6 1.5 1.4 1.3 2.4 2.0 1.8 1.6 1.5 3.5 3.2 2.8 2.4 2.4 See Section 11.4. 7 of ASCE 7 Note: Use straight-line interpolation for intermediate values of S1 For Site Class= D and S1 = 0.445 g, F. = 1.555 1/25/2016 12:06 Pl\ Design Maps Detailed Report http://ehp1-earthquake.cr.usgs.gov/ designmaps/us/report.php?template ... 3 of6 Equation (11.4-1): SMs = FaSs = 1.035 X 1.161 = 1.203 g Equation (11.4-2): SM1 = fvS1 = 1.555 X 0.445 = 0.692 g Section 11.4.4 -Design Spectral Acceleration Parameters Equation (11.4-3): Sos = ½ SMs = ½ X 1.203 = 0.802 g Equation (11.4-4): 501 = ½ SM1 = ½ X 0.692 = 0.461 g Section 11.4.5 -Design Response Spectrum From Figure 22-12 c33 TL = 8 seconds I'll U'I c .!! 'Iii .. II "ii " " < Ill .. C 0 a. .. Ill cc ii t Ill a. U'l Figure 11.4-1: Design Response Spectrum 501 = 0.461 T0 =0.115 T5 = 0.575 T < T•: S. = Sil$ (0.4 + 0.6T /T0 ) T.!liTtiTS:s."'sos T,. <TS TL: s. =S01 /T T>TL: s, .. so,TL/11 1.000 Period, T ( sec) 1/25/2016 12:06 Pl'v Design Maps Detailed Report http://ehpl-earthquake.cr.usgs.gov/designmaps/us/report.php?template ... 4 of6 Section 11.4.6 -Risk-Targeted Maximum Considered Earthquake (MCER) Response Spectrum The MCE" Response Spectrum is determined by multiplying the design response spectrum above by 'i s,,,, = 1. 203 ... Ill Ill c .!! 1il ~ "ii 1,1 " < II UI C 0 ! iii +3 II Cl. Ill S,u = 0.692 T0 =0.115 1.5. Ts=0.575 1.000 Period, T I sec! 1/25/2016 12:06 PM Design Maps Detailed Report http://ehpl-earthquake.cr.usgs.gov/designmaps/us/report.php?template ... 5 of6 Section 11.8.3 -Additional Geotechnical Investigation Report Requirements for Seismic Design Categories D through F From Figure 22-7 c41 PGA = 0.464 Equation (11.8-1): PGAM = FPGAPGA = 1.036 x 0.464 = 0.481 g Table 11.8-1: Site Coefficient FPGA Site Class Mapped MCE Geometric Mean Peak Ground Acceleration, PGA PGA ~ 0.10 PGA = 0.20 PGA = 0.30 PGA = 0.40 PGA ~ 0.50 A 0.8 0.8 0.8 0.8 0.8 B 1.0 1.0 1.0 1.0 1.0 C 1.2 1.2 1.1 1.0 1.0 D 1.6 1.4 1.2 1.1 1.0 E 2.5 1.7 1.2 0.9 0.9 F See Section 11. 4. 7 of ASCE 7 Note: Use straight-line interpolation for intermediate values of PGA For Site Class = D and PGA = 0.464 g, FPGA = 1.036 Section 21.2.1.1 -Method 1 (from Chapter 21 -Site-Specific Ground Motion Procedures for Seismic Design) From Figure 22-17 csi CRs = 0.934 From Figure 22-18 £61 CRl = 0.987 1/25/2016 12:06 PM Design Maps Detailed Report http://ehpl-earthquake.cr.usgs.gov/designmaps/us/report.php?template ... 6 of6 Section 11.6 -Seismic Design Category Table 11.6-1 Seismic Design Category Based on Short Period Response Acceleration Parameter RISK CATEGORY VALUE OF Sos I or II Ill IV Sos< 0.167g A A A 0.167g :5i 50s < 0.33g B B C 0.33g :5i Sos < O.SOg C C D O.SOg :5i Sos D D D For Risk Category = I and S05 = 0.802 g, Seismic Design Category = D Table 11.6-2 Seismic Design Category Based on 1-5 Period Response Acceleration Parameter RISK CATEGORY VALUE OF 5 01 I or II III IV 501 < 0.067g A A A 0.067g :5i 501 < 0.133g B B C 0.133g :5i 501 < 0.20g C C D 0.20g :5i 501 D D D For Risk Category = I and S01 = 0.461 g, Seismic Design Category = D Note: When 51 is greater than or equal to 0. 75g, the Seismic Design Category is E for buildings in Risk Categories I, II, and III, and F for those in Risk Category IV, irrespective of the above. Seismic Design Category = "the more severe design category in accordance with Table 11.6-1 or 11.6-2" = D Note: See Section 11.6 for alternative approaches to calculating Seismic Design Category. References 1. Figure 22-1: http://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-l.pdf 2. Figure 22-2: http ://earthquake. usgs. gov /hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-2. pdf 3. Figure 22-12: http://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-12. pdf 4. Figure 22-7: http ://earthquake. usgs. gov /hazards/designma ps/downloads/pdfs/2010_ASCE-7 _Figure_22-7. pdf 5. Figure 22-17: http://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7_Figure_22-17.pdf 6. Figure 22-18: http://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE-7 _Figure_22-18. pdf 1/25/2016 12:06 PM APPENDIXC GRADING GUIDELINES Grading should be performed to at least the minimum requirements of the local governing agencies, the California Building Code, 2013, the geotechnical report and the guidelines presented below. All of the guidelines may not apply to a specific site and additional recommendations may be necessary during the grading phase. Site Clearina: Trees, dense vegetation, and other deleterious materials should be removed from the site. Non- organic debris or concrete may be placed in deeper fill areas under direction of the Soils engineer. Subdrainaa:e 1. During grading, the Geologist and Soils Engineer should evaluate the necessity of placing additional drains. 2. All subdrainage systems should be observed by the Geologist and Soils Engineer during construction and prior to covering with compacted fill. 3. Consideration should be given to having subdrains located by the project surveyors. Outlets should be located and protected. Treatment of Existina: Ground 1. All heavy vegetation, rubbish and other deleterious materials should be disposed of off site. 2. All surficial deposits including alluvium and colluvium should be removed unless otherwise indicated in the text of this report. Groundwater existing in the alluvial areas may make excavation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months. 3. Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions and compacted to fill standards. Fill Placement 1. Most site soil and bedrock may be reused for compacted fill; however, some special processing or handling may be required (see report). Highly organic or contaminated soil should not be used for compacted fill. 2. Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts not to exceed six inches in thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a horizontal plane, unless otherwise found acceptable by the Soils Engineer. (1) 3. If the moisture content or relative density varies from that acceptable to the Soils engineer, the Contractor should rework the fill until it is in accordance with the following: a) Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pre-watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. b) Each six inch layer should be compacted to at least 90 percent of the maximum density in compliance with the testing method specified by the controlling governmental agency. In this case, the testing method is ASTM Test Designation D-1557-91. 4. Side-hill fills should have a minimum equipment-width key at their toe excavated through all surficial soil and into competent material (see report) and tilted back into the hill. As the fill is elevated, it should be benched through surficial deposits and into competent bedrock or other material deemed suitable by the Soils Engineer. 5. Rock fragments less than six inches in diameter may be utilized in the fill, provided: a) They are not placed in concentrated pockets; b) There is a sufficient percentage of fine-grained material to surround the rocks; c) The distribution of the rocks is supervised by the Soils Engineer. 6. Rocks greater than six inches in diameter should be taken off site, or placed in accordance with the recommendations of the Soils Engineer in areas designated as suitable for rock disposal. 7. In clay soil large chunks or blocks are common; if in excess of six (6) inches minimum dimension then they are considered as oversized. Sheepsfoot compactors or other suitable methods should be used to break the up blocks. 8. The Contractor should be required to obtain a minimum relative compaction of 90 percent out to the finished slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back to the compacted core, or by direct compaction of the slope face with suitable equipment. If fill slopes are built "at grade" using direct compaction methods then the slope construction should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be back rolled approximately every 4 feet vertically as the slope is built. Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope. (2) In addition, if a method other than over building and cutting back to the compacted core is to be employed, slope compaction testing during construction should include testing the outer six inches to three feet in the slope face to determine if the required compaction is being achieved. Finish grade testing of the slope should be performed after construction is complete. Each day the Contractor should receive a copy of the Soils Engineer's "Daily Field Engineering Report" which would indicate the results of field density tests that day. 9. Fill over cut slopes should be constructed in the following manner: a) All surficial soils and weathered rock materials should be removed at the cut-fill interface. b) A key at least 1 equipment width wide (see report) and tipped at least 1 foot into slope should be excavated into competent materials and observed by the Soils Engineer or his representative. c) The cut portion of the slope should be constructed prior to fill placement to evaluate if stabilization is necessary, the contractor should be responsible for any additional earthwork created by placing fill prior to cut excavation. 10. Transition lots (cut and fill) and lots above stabilization fills should be capped with a four foot thick compacted fill blanket (or as indicated in the report). 11. Cut pads should be observed by the Geologist to evaluate the need for overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones, and/or due to differing expansive potential of materials beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases. 12. Exploratory backhoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Grading: Observation and Testing: 1. Observation of the fill placement should be provided by the Soils Engineer during the progress of grading. 2. In general, density tests would be made at intervals not exceeding two feet of fill height or every 1,000 cubic yards of fill placed. This criteria will vary depending on soil conditions and the size of the fill. In any event, an adequate number of field density tests should be made to evaluate if the required compaction and moisture content is generally being obtained. 3. Density tests may be made on the surface material to receive fill, as required by the Soils Engineer. (3) 4. Cleanouts, processed ground to receive fill, key excavations, subdrains and rock disposal should be observed by the Soils Engineer prior to placing any fill. It will be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for observation. 5. A Geologist should observe subdrain construction. 6. A Geologist should observe benching prior to and during placement of fill. Utility Trench Backfill Utility trench backfill should be placed to the following standards: 1. Ninety percent of the laboratory standard if native material is used as backfill. 2. As an alternative, clean sand may be utilized and flooded into place. No specific relative compaction would be required; however, observation, probing, and if deemed necessary, testing may be required. 3. Exterior trenches, paralleling a footing and extending below a 1 : 1 plane projected from the outside bottom edge of the footing, should be compacted to 90 percent of the laboratory standard. Sand backfill, unless it is similar to the inplace fill, should not be allowed in these trench backfill areas. Density testing along with probing should be accomplished to verify the desired results. (4)