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HomeMy WebLinkAboutCT 2018-0005; VILLAGE WALK; GEOTECHNICAL REPORT; 2019-12-08PRELIMINARY GEOTECHNICAL INVESTIGATION For Proposed 8-Townhouse House Development 341-347 Oak Avenue Drive Carlsbad California F ~ r ........ . . . .,. DEC l 7 2019 • .1. By: STRATA-TECH, INC. W.O.284018.1 J AN D C/~\.-· ' _ i ·~v1ENT J:; c ~~RI Updated. 08-DECEMBER-2019 For: TMS HIGHLAND INVESTMENTS, LLC TONYSFREDDO 29250 PASEO SEDANO SAN JUAN CAPISTRANO CALIFORNIA 92675 STRATA-TECH, INC_ 310. 968. 2999 stratatech@yahoo.com G 8 0 C 0 N S U L T A N T ~ Januaryl0, 2018 Updated: 08-Dec-2019 TMS Highland Investments, LLC Tony Sfreddo 29250 Paseo Sedano San Juan Capistrano, California 92675 tsfreddo@icloud.com Subject: Gentlemen: W.O. 284018.1 Preliminary Geotechnical Investigation, Proposed 8 Townhouse House Developments, 341-347 Oak A venue Drive, Carlsbad, California. Pursuant to your request and authorization, Strata-Tech, Inc., has prepared this geotechnical investigation at the subject site. -The purposes of the investigation were to determine the general engineering characteristics of the soils on and underlying the site and to provide recommendations for the design of foundations, pavements and underground improvements. PROPOSED DEVELOPMENT The proposed development is an 8-unit townhouse project on a single lot. The approach is to grade the site after demolition of the existing structures and clearing the land. Grading will for the most part consist of excavation for the building pad and semi-subterranean parking (see grading plans) Scarification and compaction of the exposed excavation bottom shall be performed due to disturbances caused by the excavation process. Retaining walls are planned and shoring will be employed where adjacent structures are potentially undermined. Existing property line masonry walls not being removed STRATA-TECH,INC. BEOCONSULTANTB TMS Highland Investments, LLC Geotechnical Investigation 2 W. 0. 284018.1 Rev: 08-Dec-2019 shall be surveyed and a photo log made before any excavation or demolition commences. Attached find the shoring design parameter calculations. The building will be supported on continuous footings as described in reference( I) structural loads are anticipated to to be on the order of 3kips/lineal ft for wall loads and 30kips for columns. Strata-tech, Inc. has reviewed the grading plans provided by the Civil for the project on 10-10-2018. The grading plan is used here to plot geotechnical data. PURPOSE AND SCOPE OF SERVICES The scope of the study was to obtain subsurface infonnation within the project site area and to provide recommendations pertaining to the proposed development and included the following: 1. A cursory reconnaissance of the site and surrounding areas. 2. Excavation of exploratory geotechnical test borings to determine the subsurface soil and groundwater conditions. 3. Collection ofrepresentative bulk and/or undisturbed soil samples for laboratory analysis. 4. Laboratory analyses of soil samples including determination of in-situ and maximum density, in-situ and optimum moisture content, shear strength and consolidation characteristics, expansion potential. 5. Preparation of this report presenting results of our investigation and recommendations for the proposed development. SITE CONDITIONS The subject site is a rectangular developed lot on the south side of Oak Drive, east of intersection with Pacific Coast Hwy, Carlsbad, California. The property is developed with single story residential STRATA-TECH,INC. BEOCONSULTANTS TMS Highland Investments, LLC Geotechnical Investigation 3 W. 0. 284018.1 Rev : 08-Dec-2019 Fourplex structures, landscaping and appurtences. The site slopes very gently toward the north toward Oak. The site location is shown on the attached vicinity Map, Plate No. 1. Site configuration is further illustrated on the Site Plan, Plate 2. REGIONAL GEOLOGIC CONDITIONS Regional Geology of San Diego County is divided into three distinct geologic areas: the Coastal Plain region, Peninsular Ranges region, and Salton Trough region. 'The Coastal Plain region includes most of western San Diego County and consists primarily of Mesoz.oic crystalline rocks underlain by marine and non-marine sedimentary rocks. In this region, drastic land and sea fluctuations have preserved ancient marine rocks up to elevations around 900 feet and ancient river deposits up to 1,200 feet. The Peninsular Ranges region includes much of eastern San Diego County and consists primarily of plutonic rocks that formed from the cooling of molten magmas deep within the Earth's crust between 140 and 90 million years ago. Other sediments are now preserved in this region as marbles, slates, schist, quartzites, and gneiss deposits. The Salton Trough or Colorado Desert region includes the eastern third of San Diego County and is characterized by late Miocene-aged marine sedimentary rocks and Pleistocene-aged stream and playa lake deposits (Demere n.d .). Locally Carlsbad is within the coastal portion of the Peninsular Ranges Geornorphic Province, a region characterized by northwest-trending structural blocks and intervening fault z.ones. Typical lithologies in the Peninsular Ranges include a variety of igneous, intrusive rocks associated with the Cretaceous-age (between approximately 65 and 135 million years old) Southern California Batholith (a large igneous intrusive body). In western San Diego County, batholithic rocks are often intruded into Jurassic-age (between approximately 135 and 195 million years old) metavolcanic and/or metasedimentary units, with these basement rocks locally overlain by Tertiary-age (between approximately 2 and 65 million years old) marine and non-marine sedimentary strata. Tertiary rocks STRATA-TECH,INC. BEOCONSULTANTB TMS Highland Investments, LLC Geotechnical Investigation 4 W. 0. 284018.1 Rev: 08-Dec-2019 in the western portion of the county are associated primarily with a number of sea level advance and retreat cycles over approximately the last 55 million years, including sedimentary units in Carlsbad and vicinity as described below. Topographically, the Peninsular Ranges Province is composed of generally parallel ranges of steep- sloping hills and mountains separated by alluvial valleys. More recent uplift and erosion ha s produced the characteristic canyon and mesa topography present today in western San Diego County, as well as the deposition of surficial materials including Quaternary-age (less than approximately two million years old) alluviwn, colluvium and topsoil. The geology in the Oceanside Quadrangle, in which the city is located. There are no active faults that run directly through Carlsbad. Additionally, the California Geological Survey does not include Carlsbad on its list of cities affected by Alquist-Priolo Earthquake Fault Zones. The nearest fault to the city is the Newport-Inglewood-Rose Canyon Fault, which runs offshore of the western edge of the city and is considered active. 2 Other fauhs in the region include the Coronado Bank, La Nacion, Elsinore, Agua Caliente, and San Jacinto. Fault activity has the potential to result in ground shaking, which can be of varying intensity depending on the intensity of earthquake activity, proximity to that activity, and local soils and geology conditions. Carlsbad is located within a seismically active region, and earthquakes have the potential to cause ground shaking of significant magnitude. Although located near fault lines, Carlsbad lies within a medium-low probabilistic peak ground acceleration zone. Historic documents record that an earthquake centered either on the Rose Canyon or Coronado Bank fauhs struck San Diego on May 27, 1862, damaging buildings in Old Town and causing ground rupture near the San Diego River mouth. This earthquake is believed to have had a magnitude of about 6.0 based on descriptions of the damage it caused. The strongest recorded earthquake in the San Diego area was a magnitude of 5.3 on the Richter scale that struck on July 13, 1986, on the Coronado Bank fault, 25 miles offshore of Solana Beach. There have been several moderate earthquakes recorded within the Rose Canyon Fault Zone as well. On June 17, 1985 , three STRATA-TECH,INC. BECCCNSULTANTS TMS Highland Investments, LLC Geotechnical Investigation 5 W. 0. 2840 18.1 Rev: 08-Dec-2019 earthquakes hit San Diego measuring 3.9, 4.0, and 3.9, respectively, and on October 28, 1986, a stronger earthquake with a magnitude of 4. 7 occurred. FIELD INVESTIGATION The field investigation was performed on January 4, 2018, consisting of two hand auger borings. The locations are shown on the attached Site Plan, Plate 2. As the excavation progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing. Description of the soils encountered is presented on the attached Record of Subsurface Exploration Logs. The data presented on these logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring location and the date excavated. It is not warranted to be representative of subsurface conditions at other locations and times. EARTH MATERIALS Earth materials encountered within the exploratory test borings were visually logged by a representative from STRATA-TECH, Inc . The materials were classified as artificial fill and native soils. Native soils consisted of a silty residual sandy soil to a maximum depth explored of 12 feet in test pit 2. Groundwater was not encountered in any of our subsurface exploration. GEOLOGIC HAZARDS Liquefaction, fault rupture and tsunami potential for this site are considered improbable. STRATA-TECH,INC. 13£0CONSULTANTS TMS Highland Investments, LLC Geotechnical Investigation 6 W. 0. 284018.1 Rev: 08-Dec-2019 The site is located about 46 ' above sea level and separated from the ocean by a sea cliff and approximately a quarter mile inland from the sea cliff A tsunami however credibly large is not likely to affect the site. Fault rupture for the site is also extremely remote given the absence ofactive faulting in City of Carlsbad. Liquefaction is also of very low potential. The site is underlain by shallow beach/dune sands resting on bedrock. The local gradient is east toward the railroad line and the tributary area between the sea bluff and project is small so the likelihood of a freatic surface developing beneath the site is very low so, liquefaction is not a significant concern. Historically, seismic shaking levels in the San Diego region, including Carlsbad, have not been sufficient enough to trigger liquefaction. The city has a low liquefaction risk; however, there are areas of the city that have a higher risk of liquefaction due to the presence of hydraulic soils or soils that are often saturated or characteristic of wetlands. These areas are limited to the immediate vicinity of the Buena Vista, Agua Hedionda, and Batiquitos lagoons. SEISMICITY Southern California is located in an active seismic region. Moderate to strong earthquakes can occur on numerous faults. The United States Geological Survey, California Division of Mines and Geology, private consultants, and universities have been studying earthquakes in Southern California for several decades. The purpose of the code seismic design parameters is to prevent collapse during strong ground shaking. Cosmetic damage should be expected. The principal seismic hazard to the subject property and proposed project is strong ground shaking from earthquakes produced by local faults. Secondary effects such as surface rupture, lurching, or flooding are not considered probable. STRATA-TEC ,H,INC. BEOCONSULTAN,TS TMS Highland Investments, LLC Geotechnical Investigation 2015 NEHRP SEISMIC PROVISIONS OakAve Latitude= 33.157°N, Longitude = 117.349°W Location 1.090g 0.394g PGA =0.482g C•lsbad SMs= 1.308 g SM1 = 0. 750 g1 7 PGAM = FPGAPGA = 1.200 x 0.482 = 0.578 g CONCLUSIONS AND RECOMMENDATIONS Reference Document W. 0. 284018.1 Rev : 08-Dec-2019 2015 NEHRP Provisions Site Class ~ D (default): Stiff Soil Leaf!e1 Risk Category I or II or Ill Sos= 501= 0.872 g 0.500 g1 Development of the site as proposed is considered feasible from a soils engineering standpoint, provided that the recommendations stated herein are incorporated in the design and are implemented in the field . Recommendations are subject to change based on review of final foundation and grading plans. It is recommended that the proposed structures be entirely supported by compacted fill. A minimum 2- foot thick compacted fill blanket below the bottom of the footings is recommended. The over STRATA-TECH,INC. BEOCONSULTAN,TS TMS Highland Investments, LLC Geotechnical In vestigation 8 W. 0 . 284018.J Rev: 08-Dec-2019 excavation requirement is 2 foot below footings, or 4 feet deep for 2 foot footings. The upper 3-feet are loose unsuitable for structural support. For other minor structures such as property line walls or retaining walls less than 4 feet high, competent native soils or compacted fill may be used for structural support. GRADING RECOMMENDATIONS Removal and recompaction of existing fill and loose native soils will be required to provide adequate support for foundations and slabs on grade. The depth of removal shall be 2 foot below the bottom of the footings, which is estimated to be at least 2-6 feet below existing grade. The over excavation requirement is 2 foot below footings, or 4 feet deep for 2 foot footings . Earthwork for foundation support shall include the entire building pad and shall extend a minimum of 5 feet outside exterior footing lines where feasible or to property line . Care shall be exercised not to undermine hardscape, walls, or pavements that are located on adjacent properties. Ifremovals extend to off site structures or concrete block perimeter walls that are located within 4-feet from the bottom excavation, then slot cutting or shoring will be required. The exposed excavation bottom shall be observed and approved by STRATA-TECH, Inc. and the City's grading inspector prior to processing. Dependent on field observations, removals may be adjusted up or down. Subsequent to approval of the excavation bottom, the area shall be scarified 6 inches, moisture conditioned as needed, and compacted to a minimum of 90 percent relative compaction. Fill soils shall be placed in 6 to 8 inch loose lifts, moisture conditioned as needed, and compacted to a minimum of90 percent relative compaction. This process shall be utilized to finish grade. Grading for hardscape areas shall consist of removal and recompaction of soft surficial soils. Removal depths are estimated at 3 feet. Earthwork shall be performed in accordance with previously specified methods. STRATA-TECH,INC. BEOCONSULTAMTS TMS Highland Investments, LLC Geotechnical Investigation 9 W. 0. 284018.1 Rev : 08-Dec-2019 Grading and/or foundation plans shall be reviewed by the soil engineer. All recommendations are subject to modification upon review of such plans. It is the opinion of the undersigned, a duly registered engineer, based upon our work as outlined in the referenced report and in those referenced by it, that if constructed in accordance with our recommendations and properly maintained, (1) the proposed structure(s) will be safe against hazard from landslide, settlement, or slippage, and that (2) the proposed building or grading construction will have no adverse effect on the geologic stability of property outside of the building site. The nature and extent of tests conducted for purposes ofthis declaration are, in the opinion of the undersigned, in conformance with generally accepted practice in the area. Test findings and statements of professional opinion do not constitute a guarantee or warranty, expressed or implied. FOUNDATIONS ON COMPACTED FIL The proposed building may be supported by continuous spread and isolated footings placed a minimum depth of 24 inches below lowest adjacent grade utilizing an allowable bearing value of 2,000 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. Minimum Minimum Bearing Increase Maximum Type Depth Width Value Width Depth (psf) (inches) (inches) (psf) (psf/ft) (psf/ft) Continuous 24 12 2000 180 440 3500 Interior Pad 18 24 2000 180 440 3500 It is recommended that all footings be reinforced with a minimum of two no. 4 bars (l top and bottom). The structural engineer's reinforcing requirements should be followed if more stringent. STRATA-TECH,INC. BEOCONSULTAMTS TMS Highland Investments, LLC Geotechnical Investigation 10 W.O.284018.1 Rev: 08-Dec-2019 Footing excavations shall be observed by a representative ofSTRA TA-TECH, Inc. prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil conditions are exposed mitigation will be recommended. FOUNDATIONS ON COMPETENT NATIVE SOILS -for Minor Structures Minor structures may be supported by continuous spread footings placed a minimum depth of24 inches below lowest adjacent grade. An allowable bearing value of 1,500 pounds per square foot may be used in design. This value is for dead plus live load and may be increased I /3 for total including seismic and wind loads where allowed by code. All footing excavations shall be observed by a representative of STRATA-TECH, Inc. prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil conditions are exposed, mitigation will be recommended. LATERAL DESIGN Lateral restraint at the base of footings and on slabs may be assumed to be the product of the dead load and a coefficient of friction of.30. Passive pressure on the face of footings may also be used to resist lateral forces. A passive pressure of zero at the surface of finished grade, increasing at the rate of300 pounds per square foot of depth to a maximum value of3,000 pounds per square foot, may be used for compacted fill or native soils at this site. When passive pressure and friction are combined for evaluating the lateral resistance, the value of the passive pressure should be limited to 2/3 of the values given above. RETAINING WALLS Unrestrained walls up to 5-feet in height retaining drained earth may be designed for the following: STRATA-TECH,INC. 13EOCONSULTANTS TMS Highland Investments, LLC Geotechnical Investigation Surface Slope of Retained Material Horizontal to Vertical Level 5 to 1 4 to I 3 to 1 2 to I 11 W. 0. 284018.1 Rev: 08-Dec-2019 Equivalent Fluid Pressure Pounds Per Cubic Foot 30 32 35 38 43 These values include seismic loading. Backfill should consist of clean sand and gravel. While all backfills should be compacted to the required degree, extra care should be taken working close to walls to prevent excessive pressure. Retaining walls should include subdrains consisting of 4-inch, SCH 40 or SOR 35 perforated pipe surrounded by I cubic foot per lineal foot of crushed rock. All wall backfill should be compacted to a minimum of90 percent relative compaction. Section F-F, sheet 3of grading plan identifies a condition requiring temporary support of an adjacent property line wall retaining a small amount of fill. Attached please find temporary stability, shoring design parameters. Soldier pile calculations are presented here . All retaining structures should include appropriate allowances for anticipated surcharge loading, where applicable. In this regard, a uniformly distributed horizontal load equal to one-half the vertical surcharge shall be applied when the surcharge is within a horizontal distance equal to the wall height. Retaining wall footing excavations shall be founded entirely in competent native soils or compacted fill. Footing bottoms shall be observed by a representative of STRATA-TECH, Inc., to verify competent conditions. EXPANSIVE SOILS STRATA-TECH,INC. BEOCONSULTANTB TMS Highland Investments, LLC Geotechnical Investigation 12 W.O.284018.1 Rev : 08-Dec-2019 The onsite soils are non plastic granular and Very low expansive. The foundations as contemplated are consistent with the requirements of sec. 1808.6 of the 2016 CBC. SOIL CORROSION Site soils are moderately corrosive to metals which should be wrapped. See attached soil corrosion test results. Testing was conducted in accordance with; Soluble Sulfates per (CT.417), Soluble chlorides per (CT.422), Min. Resistivity per (CT.642). SETTLEMENT The maximum total post-construction settlement is anticipated to be on the order of I /2 inch. Differential settlements are expected to be less than 1 /2 inch, measured between adjacent structural elements(20'). SUBSIDENCE & SHRINKAGE Subsidence over the site during grading is anticipated to be on the order of .5 feet. Shrinkage of reworked materials should be in the range of 1 0 to 15 percent. HARDSCAPE SLABS The surface soils are non-plastic with low expansion potential. Where concrete slabs on grade are utilized, the slab shall be supported on at least I foot of engineered fill compacted to a minimum of 90 percent relative compaction. Slabs should be at least 4 inches thick and reinforced with a minimum ofno. 3 bars 24 inches on center both ways. The soil should be kept moist prior to casting the slab. However, if the soils at grade become disturbed during construction, they should be brought to approximately optimum moisture content and rolled to a finn, unyielding condition prior to placing concrete. STRATA-TECH,INC. BEOCONSULTANTS TMS Highland Investments, LLC Geotechnical Investigation 13 W.O.284018.1 Rev : 08-Dec-2019 In areas where a moisture sensitive floor covering will be used, a vapor barrier consisting of a plastic fihn (6 ml polyvinyl chloride or equivalent) should be used. The vapor barrier should be properly lapped and sealed. Since the vapor barrier will prevent moisture from draining from fresh concrete, a better concrete finish can usually be obtained if at least 2 inches of wet sand is spread over the vapor barrier prior to placement of concrete. UTILITY LINE BACKFILLS All utility line backfills, both interior and exterior, shall be compacted to a minimum of 90 percent relative compaction and shall require testing at a maximum of2-foot vertical intervals. DRAINAGE Positive drainage should be planned for the site. Minimum drainage should be 2 percent for landscape areas and 1 percent for hardscape. Drainage should be directed away from structures via non-erodible conduits to suitable disposal areas. The structure should utiliz.e roof gutters and down spouts tied directly to yard drainage to allow storrnwater to be dispersed away from the building foundations. Unlined flowerbeds, planters, and lawns should not be constructed against the perimeter of the structure. If such landscaping (against the perimeter of a structure) is planned, it should be properly drained and lined or provided with an underground moisture barrier. Irrigation should be kept to a minimum. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are called to the attention of the engineers for the project and incorporated into the plans and that the necessary steps are taken to see that the Contractors and Subcontractors carry out such recommendations in the field. STRATA-TECH,INC. BEOCONSULTANTS TMS Highland Investments, LLC Geotechnical Investigation SUPPLEMENTAL CONSULTING 14 W. 0. 284018.1 Rev : 08-Dec-20 I 9 During construction, a nwnber of reviews by this office are recommended to verify site geotechnical conditions and conformance with the intentions of the recommendations for construction. Although not all possible geotechnical observation and testing services are required by the City of Los Angeles. The following site reviews are advised, some of which will probably be required by the City: Foundation excavation review for retaining walls Reinforcement placement for all foundations Pre-saturation checks for all concrete flatwork Drainage and rock placement behind retaining walls Backfill compaction behind retaining walls AGENCY REVIEW Required Advised Required Required Required AU soil, geologic and structural aspects of the proposed development are subject to the review and approval of the governing agency(s). It should be recognized that the governing agency (s) can dictate the manner in which the project proceeds. They could approve or deny any aspect of the proposed improvements and/or could dictate which foundation and grading options are acceptable. Supplemental geotechnical consulting in response to agency requests for additional information could be required and will be charged on a time and materials basis. LIMITATIONS This report presents recommendations pertaining to the subject site based on the asswnption that the subsurfuce conditions do not deviate appreciably from those disclosed by our exploratory excavations. Our recommendations are based on the technical information, our understanding of the proposed construction, and our experience in the geotechnical field. We do not guarantee the performance of the project, only that our engineering work and judgments meet the standard of care of our profession at this time. STRATA-TECH,INC. BEOCONSULTAMTS TMS Highland investments, LLC Geotechnical Engineering Investigation 16 This report is subject to review by the controlling authorities for this project. We appreciate this opportunity to be of service to you. Respectfully submitted, STRATA-TECH, INC. Roland Acufia President Enclosures: Appendix A: Laboratory Results and Engineering Calculations Appendix B: Calculations Appendix C: Specifications for Grading Plate I: Vicinity Map Plate 2: Site Plan and Boring Location Map Test Boring Logs W. 0. 284018.1 Rev: 12-Dec-2019 / VICINITY MAP Geotechnical Engineering Investigation 341-347 Oak Ave Carlsbad, California STRATA -TECH, INC. Work Order 284018 Plate No . 1 LOCAL GEOLOGY Geotechnical Engineering Investigation 341 -347 Oak Ave Carlsbad, California STRATA -TECH, INC. Work Order 284018 Plate No. 1 ' ', ', ' ' , ' \ ' ' ' ' ' \ NEAR SOURCE FAULT MAP ' ' ' ' ' \ \ \ ' ' Geotechnical Engineering Investigation 341-347 Oak Av Carlsbad, California STRATA -TECH, INC. Work Order 2840118 Plate No. 4 RECORD OF SUBSURFACE EXPLORATION ~-~ -Date Preliminary Geotechnical Investigation (/) ~j ~ ~ C !:=, (/)c a. ::Ii::' Q) u .c 341-34 7 Oak ave E iii "O 0-3: a. ro ·o ~ i::' Q) Cl) ~~ 0 0 Carlsbad, California u B Work Order 284018 Test Pit No. 1 Description of Earth Materials 0 -Orange-Brown, fn sand 2 -Orange-brown , fn-med Sand,w/trace of clay, dry 3.2 113 4 - 6 -Orange-tan, fn-med , silty sand, dry 8 -Bottom at 8' Feet. No Ground Water. No Caving . RECORD OF SUBSURFACE EXPLORATION ~-~ -Date 1/0/1900 Preliminary Geotechnical Investigation (/) ~j ~ Q) C a. ::i i::' (/)c Q) u .c 341-34 7 Oak ave E iii "O 0-3: a. ro ·o ~ i::' Q) Cl) ~~ 0 0 Carlsbad, California u B Work Order 284018 Test Pit No. 2 Description of Earth Materials 0 -Brown, Silty Sand w/ Roots 5 -Orange-Brown, fn-med, Sand , dry 7.2 114.1 10 -9.1 113.9 Yellow-Tan Sand , Dense, damp 15 - Bottom at 15 Feet. No Ground Water. No Caving. - STRATA -TECH, INC. STRATA-TECH,INC. BEOCONSULTANTS APPENDIX A This appendix contains a description of the field investigation, laboratory testing procedures and resuhs, site plan, and exploratory logs. FIELD INVESTIGATION The field investigation was performed on January 4, 2018, consisting of the excavation of two exploratory hand auger borings at locations shown on the attached Site Plan, Plate 2. As excavation progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing Sample Retrieval Undisturbed samples of earth materials were obtained at frequent intervals by driving a thin-walled steel sampler by slide hammer. The material was retained in brass rings of 2.41 inches inside diameter and 1.00 inch height. The central portion of the sample was in close-fitting, watertight containers for transportation to the laboratory. Descriptions of the soils encountered are presented on the attached boring Logs. The data presented on these logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring location and the date excavated. It is not warranted to be representative of subsurface conditions at other locations and times. Laboratory Testing Field samples were examined in the laboratory and a testing program was then established to develop data for preliminary evaluation of geotechnical conditions. Moisture Density Field moisture content and dry density were determined for each of the undisturbed soil samples. The dry density was determined in pounds per cubic foot. The moisture content was determined as a percentage of the dry soil weight. The results of the tests are shown in the test results section of this appendix. Compaction Character Compaction tests were performed on bulk sample of the existing soil in accordance with ASTM D1557. The results of the tests are shown in the test results section of this appendix. STRATA-TECH,INC. BEOCONSULTANTS Expansion Index Expansion tests on selected samples are conducted per (ASTM: d-4829) Shear Strength The ultimate shear strengths of the soiL remolded soil, highly weathered bedrock and bedrock was determined by performing direct shear tests. The tests were performed in a strain-controlled machine manufactured by GeoMatic. The rate of deformation was 0.005 inches per minute . Samples were sheared under varying confining pressure, as shown on the "Shear Test Diagrams". The samples indicated as saturated were artificially saturated in the laboratory and were shear under submerged conditions. The results of tests are based on 80 percent peak strength or ultimate strength, whichever is lower, and are attached. In addition, a shear was performed on an upper layer sample remolded to 90- percent of the laboratory standard with low confining pressure. TEST RES UL TS Maximum Density/Optimum Moisture (ASTM:D-1557) Boring Depth in Feet Maximum Density Optimum Moisture (nd) (%) 2 1 -3 126 10.5 In-Situ Dry Density/ Moisture Boring Depth in Feet Dry Density Moisture (nd) (%) I 2 I 12.0 9.1 2 5 114.1 11.0 2 10 113.7 11.9 Direct Shear Boring Depth in Feet Cohesion Angle of Internal Friction (psf) (degrees) 2 1-3 125 32 2 5 110 34 SHEAR TEST RESULT ( Hb-2@5 Feet l 4~-------.---~------,------, 3 ----~ ci-✓ Cl) . .._ Cl) a. 2 / g V Cl) Cl) ~ / u5 1 . V V 0 0 1 2 3 4 Confining Pressure (kips/sq. ft.) Stress -Displacement Diagram C 4 Cl) ♦1 KIP 6 3 Cl) 2 ~• •• ,-.-.-~I IL ••••••••• ■2KIP Cl) ········••1• ~ 1 ••••••••• ••••••••• .&3 KIP u5 0 0 1 2 Horizontal Displacement (X 1/10 inch) insitu samples were submerged for at least 24 hours. The sample had a density of 114 lbs./cu.ft. and a moisture content of 17.2 %. Cohesion = 110 psf Friction Angle = 34 degrees Based on Ultimate Strength Geotechnical Engineering Investigation 341-347 Oak Ave Carlsbad, California STRATA -TECH, INC. Work Order 284018 Plate No. ( Cl) Cl) ~ u5 SHEAR TEST RESULT Hb-2 @ 1 to 3 Feet (Remolded to 90% R.C.) 4~------~-----------, 3 1------+----+-----+--------t ....... .i:::: er ~ / a 2 ,__ ______________ V __ ------i i .v u5 / 1 / v .,,,, 0 ,..__ __ __. ___ __._ ___ ~--~ 0 1 2 3 Confining Pressure (kips/sq. ft.) Stress -Displacement Diagram 4.----------,--------, 3 1---------+--------< -~•···········. 2 1---_.--,.~ ... -■ ■ • ■-11 ~~-~~~I I 1 ••• ..,..,~~-- 0 0 2 Horizontal Displacement (X 1/10 inch) 4 ♦1 KIP ■2 KIP .A3 KIP Remolded samples were submerged for at least 24 hours. l The sample had a density of 115.2 lbs./cu.ft. and a moisture content of 16.8 %. Cohesion = 125 psf Friction Angle = 32 degrees Based on 80% Peak Strength or Ultimate Strength, Whichever is lower Geotechnical Engineering Investigation 341-347 Oak Ave Carlsbad, California STRATA -TECH, INC. Work Order 284018 Plate No. Strata-Tech, Inc. 1920 Pacific Ave., # 16060 Long Beach, CA 90806 Project: Oak Street Carlsbad, CA pH 7.1 ANAHEIM TEST LAB, INC 196 Technology Drive, Unit D Irvine, CA 92618 PHONE (949)336-6544 ANALYTICAL REPORT CORROSION SERIES SUMMARY OF DATA DATE: 10/15/18 P.O. NO: Verbal LAB NO: C-2327 SPECIFICATION: CTM-417 /422/643 MATERIAL: Sand SOLUBLE SULFATES per CT. 417 SOLUBLE CHLORIDES MIN. RESISTIVITY per CT. 422 per CT. 643 ppm ppm ohm-cm 37 24 8,000 RESPECTFULLY SUBMITTED WES BRIDGER CHEMIST APPENDIX B SHOREING DESIGN PARAMETERS /L 6 0 5 6 t'- ~KOth ~ 5 2 ---- 4 8 4 4 12" 0 PILES IA. @ 0 FILL / / I. SOLDIER 6' O.C. WITH 4 BACK CO C E-: 3 8 . ~ . . ~ ·. ~ I EXIST. BLOCK .._ ~ WALL ~ ~ ~ ~<) ,,_"-,~ r-1 /1 v-[XIST. FG ~ LT I ., l ~· - BAO ;:-ILL 'MTH EA GRAVEL -p OF OSED SUBDRAI , -~ "'· :._•I too~j .... " ... . ' ·~ (f: . -· ,.-: . . .... -. f .• -~ ~: ~~;I :-· ,.-. .... J. '° .,. 1--: .~ t..,•~ ~~,-: > If .. ,: ~.t !~> :::: ...... .,. ,"< ,,,· •~. ,.. i.:,..,;..-- 36 20 24 SCALE. HO Z: VER : 28 .. =4' 1''=4' 32 Proposed Retaining Wall ACTIVE PRESSURE D ~ I He H = 7 ft He= 3.4 ft §= 59.2 ° F.S. = 1.25 Y}:,m = 120 pct = 0.12 C = 110 psf = 0.11 X' = 34 ° § = 45° + x-m I 2 Cm= CI F.S. = 0.09 ksf ><'m = tan-1 ( tan .0 / F.S.) 28.35 degrees D = ( H -He) tan ( 90° -§ ) = 2.15 ft L = ( ( H -He ) 2 + D 2 ) 112 = 4.19 ft Free Body Diagram PA b a-fm kcf ksf W=a + b W = A 'Pm = 0.5 D ( H + He ) ".>:, 1.34 kips/LF a= Cm L sin ( 90° + ><'m) I sin ( § -><'m) = 0.65 kips/LF b = W -a = 0.69 kips/LF PA= b tan ( § -><'m) = 0.41 kips/LF Design EFP = 2 PA/ H 2 = 16.7 pef Geoteehnieal Engineering Investigation 342-347 Oak Avenue Carlsbad, California Use 17 pef Work Order 284018 Plate No. STRATA -TECH, INC. Proposed Retaining Wall D H ACTIVE PRESSURE He H = 6 ft He= 3.3 ft §= 57.1 ° F.S. = 1.50 Free Body Diagram PA b a-fm PA __._V/1 'Jo rn = 125 pef = 0.125 kef C = 110 psf = 0.11 ><' = 34 ° § = 45° + X' m / 2 Cm= CI F.S. = 0.07 ksf .0m = tan-1 ( tan .0 / F.S.) 24.21 degrees D = ( H -He ) tan ( 90° -§ ) = 1. 75 ft L = ( ( H -He ) 2 + D 2 ) 112 = 3.22 ft ksf W=a + b W = A 'Pm = 0.5 D ( H + He ) '1o 1.02 kips/LF a= Cm L sin ( 90°+ .0m)/sin ( §-.0m) = 0.38 kips/LF b = W -a = 0.64 kips/LF PA= b tan ( § -.0m) = 0.41 kips/LF Design EFP = 2 PA/ H 2 = 22.8 pef Geoteehnieal Engineering Investigation 341 -347 Oak Ave Carlsbad, CA Use 30 pcf Work Order 284018 Plate No. STRATA -TECH, INC. SOLDIER PILE DESIGN Bearing Material: Section: Properties of Bearing Material: Wet Density (g) Cohesion (C) Angle of Friction (f ) Ka Kp Design Parameters: g 1 H1 H2 Terrace F-F = = = = = = = = Design EFP = Spacing = Solve Mand N by Trial and Error Method: M = N = Active Pressures at C, D, E, F, per Diameter of Pile: C = 77. 8 psf D = 111 .4 E = 103.5 psf F = 298.3 Passive Pressures at A, B, G, H, per Diameter of Pile: A = 413.8 psf B = 2850.1 G = 5609.1 psf H = 6030.2 Check Shear Force, per Diameter of Pile: RHS = LHS = Unbalanced Force = Check Moment at Tip of Pile, per Diameter of Pile: RHS = LHS = Unbalanced Moment = 120 pcf 110 psf 34 degrees 0.283 3.537 120.0 pcf 6.5 feet 0.0 foot 20.0 pcf 6.0 D 5.740 feet 0.992 foot psf psf psf psf 9.5 psf 9.5 psf 0.0 psf 29.3 kips-ft 29.5 kips-ft -0.2 kips-ft Maximum Moment Occurs at Point of Fixity, Where V = 0 Point of Fixity from Top of Bearing Material = 2.9 feet 10.0 kips-ft 7.0 feet 13.5 feet Maximum Moment per Diameter of Pile = Embedment Depth into Bearing Material = Total Depth of Pile = Geotechnical Engineering Investigation 341-347 Oak Ave Carlsbad, California STRATA -TECH, INC. Work Order 284018 Plate No. STRATA-TECH,INC. BEOCONSULTANTS SITE CLEARING APPENDIXC SPECIFICATIONS FOR GRADING All existing vegetation shall be stripped and hauled from the site. PREPARATION After the foundation for the fill has been cleared, plowed or scarified, it shall be disced or bladed until it is uniform and free from large clods, brought to a proper moisture content and compacted to not less than 90 percent of the maximwn dry density in accordance with ASTM:D-1557 (5 layers -25 blows per layer; 10 lb. hammer dropped 18"; 4" diameter mold). M4TERIALS On-site materials may be used for fill, or fill materials shall consist of materials approved by the Soils Engineer and may be obtained from the excavation of banks, borrow pits or any other approved source. The materials used should be free of vegetable matter and other deleterious substances and shall not contain rocks or lumps greater than 8 inches in maximwn dimension. PLACING, SPREADING, AND COMPACTING FILL M4TERIALS Where natural slopes exceed five horizontal to one vertica~ the exposed bedrock shall be benched prior to placing fill. The selected fill material shall be placed in layers which, when compacted, shall not exceed 6 inches in thickness. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to ensure uniformity of material and moisture of each layer. Where moisture of the fill material is below the limits specified by the Soils Engineer, water shall be added until the moisture content is as required to ensure thorough bonding and thorough compaction. Where moisture content of the fill material is above the limits specified by the Soils Engineer, the fill materials shall be aerated by blading or other satisfactory methods until the moisture content is as specified. STRATA-TECH,INC. BEOCONSULTANTS After each layer has been placed, mixed and spread evenly, it shall be thoroughly compacted to not less than 90 percent of the maximum dry density in accordance with ASTM:D-1557 (5 layers -25 blows per layer; 10 lbs. hammer dropped 18 inches; 4" diameter mold) or other density tests which will attain equivalent results. Compaction shall be by sheepsfoot roller, multi-wheel pneumatic tire roller or other types ofacceptable rollers. Rollers shall be of such design that they will be able to compact the fill to the specified density. Rolling shall be accomplished while the fill material is at the specified moisture content. Rolling of each layer shall be continuous over the entire area and the roller shall make sufficient trips to ensure that the desired density has been obtained. The final surface of the lot areas to receive slabs on grade should be rolled to a dense, smooth surface. The outside of all fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until the outer 9 inches of the slope is at least 90 percent compacted. Compacting of the slopes may be progressively in increments of3 feet to 5 feet of fill height as the fill is brought to grade, or after the fill is brought to its total height. Field density tests shall be made by the Soils Engineer of the compaction of each layer of fill. Density tests shall be made at intervals not to exceed 2 feet of fill height provided all layers are tested. Where the sheepsfoot rollers are used, the soil may be disturbed to a depth of several inches and density readings shall be taken in the compacted material below the disturbed surface. When these readings indicate that the density of any layer of fill or portion there is below the required 90 percent density, the particular layer or portion shall be reworked until the required density has been obtained. The grading specifications should be a part of the project specifications. The Soil Engineer shall review the grading plans prior to grading. INSPECTION The Soil Engineer shall provide continuous supervision of the site clearing and grading operation so that he can verify the grading was done in accordance with the accepted plans and specifications. SEASONAL LIMITATIONS No fill material shall be placed, spread or rolled during unfavorable weather conditions. When work is interrupted by heavy rains, fill operations shall not be resumed until the field tests by the Soils Engineer indicate the moisture content and density of the fill are as previously specified. EXPANSWE SOIL CONDITIONS STRATA-TECH,INC. BEOCONSULTANTS Whenever expansive soil conditions are encountered, the moisture content of the fill or recompacted soil shall be as recommended in the expansive soil recommendations included herewith.