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HomeMy WebLinkAboutCDP 02-24; St Claire Residence; Preliminary Geotechnical Investigation; 2002-02-11Preliminary Geotechnical Investigation Undeveloped Hillside Lots 4588 Adams Street Carlsbad, California February 11, 2002 Prepared For: SEAN B. E. KELLY 7220 Trade Street, Suite 301 San Diego, California 92121 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #02-108-P C0 VINJE & MIDDLETON ENQINEERINQ, INC. I k #no ino D 2450 Vineyard Avenue, #102 JOD ffOiJ-108-P Escondido, Califomia 92029-1229 Phone (760) 743-1214 February 11, 2002 Fax (760) 739-0343 Sean B. E. Kelly 7220 Trade Street, Suite 301 San Diego, California 92121 PRELIMINARY GEOTECHNICAL INVESTIGATION, UNDEVELOPED HILLSIDE LOTS, 4588 ADAMS STREET, CARLSBAD, CALIFORNIA Pursuant to your request, Vinje and Middleton Engineering, Inc., has completed the attached Preliminary Geotechnical Investigation Report for the above-referenced project site. The following report summarizes the results of our research and review of pertinent geotechnical maps and reports, subsurface field investigation and soil sampling, laboratory testing, engineering analyses and provides conclusions and construction recommendations for the proposed development as understood. From a geotechnical engineering standpoint, it is our opinion that the individual lots are suitable for the proposed residential development and the associated improvements, provided the recommendations presented in this report are incorporated into the design and reconstruction ofthe project. The conclusions and recommendations provided in this study are consistent with the site geotechnical conditions and are intended to aid in preparation of final development plans and allow more accurate estimates of the construction costs. If you have any questions or need clarification, please do not hesitate to contact this office. Reference to our Job #02-108-P will help to expedite our response to your inquiries. We appreciate this oppori:unity to be of service to you. VINJE & MIDDLETON ENGINEERING, II Ralph M. Vinje GE #863 RMV/jt TABLE OF CONTENTS PAGE NO. I. INTRODUCTION 1 II. SITE DESCRIPTION 1 IIL PROPOSED DEVELOPMENT 1 IV. SITE INVESTIGATION 2 V. FINDINGS 2 A. Earth Materials 2 B. Groundwater 3 C. Slope Stability 3 D. Faults/Seismicity 3 E. Geologic Hazards 5 F. Laboratory Testing / Results 6 VI. CONCLUSIONS 8 VII. RECOMMENDATIONS 10 A. Grading and Earthworks 10 B. Foundations and Interior Floor Slabs 15 C. Exterior Concrete Slabs / Flatworks 17 D. Soil Design Parameters 17 E. Asphalt and PCC Pavement Design 18 F. General Recommendations 19 VIII. LIMITATIONS 22 TABLE NO. FaultZone 1 Site Seismic Parameters 2 Soil Type 3 Maximum Dry Density and Optimum Moisture Content 4 TABLE OF CONTENTS (continued) Moisture-Density Tests 5 Expansion Index Test 6 Direct Shear Test 7 Removals and Ground Treatment 8 PLATE NO. Regional Index Map 1 Geotechnical Map 2 Test Trench and Boring Logs (with key) 3-8 Geologic Cross-Sections 9 Fault - Epicenter Map 10 Retaining Wall Drain Detail 11 Isolation Joints and Re-entrant Corner Reinforcement 12 PRELIMINARY GEOTECHNICAL INVESTIGATION UNDEVELOPED HILLSIDE LOTS 4588 ADAMS STREET CARLSBAD, CALIFORNIA I. INTRODUCTION The property investigated in this work includes two residential lots located in undeveloped hillside terrain above and behind 4590 Adams Street in the City of Carisbad The property location IS depicted on a Regional Index Map attached to this report as Plate 1 We understand that the lots are planned for individual residential development Consequently he purpose of this investigation was to determine geologic and soils conditions on the two lots and their influence upon the planned development. Test hole digging, soil samplinq and laboratory testing were among the activities conducted in connection with this work which has resulted in development recommendations provided herein. II. SITE DESCRIPTION The study lots are depicted on a Geotechnical Map attached to this report as Plate 2 The sites are charactenzed by irregular, more level areas above and behind developed lots along Adams Street. Site terrain ascends into steeper brush covered terrain to the west where slope gradients approach 2:1 (horizontal to vertical) at their steepest. Access onto the lots IS provided by a concrete paved driveway along the south side of 4590 Adams vstreet. Site drainage generally sheetflows westward over the slopes. Little or no scouring is apparent as a result of concentrated run-off across the properties. Lower site areas are mantled by a light cover of native grasses. Heavy brush characterizes upper more steep site terrain. oicc^ •II- PROPOSED DEVELOPMENT Details of planned lot development are presently unavailable. However, preliminary desiqn schemes are developed and depicted on the attached Plate 2. As shown individual building surfaces will be created in the lowest portion of each lot by cut-fill grading techniques and the use of retaining walls. Maximum graded slope heights are likely to be on the order of 15 feet. Access to the southem lot will continue to be alongside 4590 Adams Street, and a new access driveway will sen/ice the northern lot. Foundation plans or construction details for the future dwellings are also not yet completed However, conventional wood-frame buildings with exterior stucco supported on shallow stiff continuous strip/spread pad concrete footings and stem/basement retaining wall type construction with slab-on-grade floors are anticipated VINJE<S?MIDDLETONENQINEERINQ, INC. 2450 VmeyardAwnue, #102, Escondido, CaUfomia 92029-122 • Phone (760).743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 2 4588 ADAMS STREET. CARLSBAD, CALIFORNIA FEBRUARY 11. 2002 IV. SITE INVESTIGATION Geotechnical conditions at the project lots were determined from geologic mapping of available surface exposures and the excavation of 8 exploratory test excavations These included 6 test trenches dug with a tractor-mounted backhoe and 2 large diameter test bonngs advanced beneath the site with a truck-mounted bucket drill rig. All of the excavations were entered and down-hole logged by our project geologist who also retained representative soil/rock samples for laboratory testing. Trench and boring locations are depicted on Plat 2. Logs of the excavations are attached with this report as Plates 3-8 Laboratory test data are summarized in a following section. V. FINDINGS The project lots are chiefly natural hillside terrain which have been modified in the lowest areas by minor grading. The hillside is underiain by sedimentary bedrock units that are mantled by soil deposits. A. Earth Materials Hillside terrain at the project site are underiain by light colored sandstone bedrock units of Eocene age. Noted exposures were fine to coarse grained, massive and cemented most commonly in a friable condition. Some dark colored claystone units are also present in limited exposures. Younger sandstone units mantles bedrock exposures at the site. These are chiefly red-brown colored terrace deposit soils which were encountered in limited exposures at depth within project test excavations. Site terrace deposit soils occur in a friable to weakly cemented condition. Fill soils cover much of the lower site terrain planned for development The fill consists chiefly of dark colored sandy soil in a loose to medium dense condition Limited amounts of asphalt and organic debris was encountered in near-surface fill soils. Grading records for fill placement were unavailable for review. The approximate distribution of site fill at the project site is depicted on Plate 2 Details of site earth materials are given on the attached logs (Plates 3-8) The indicated subsurface distribution of site earth materials is depicted on Geoloqic Cross-Sections attached to this report as Plate 9. VINJE 6? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • FOA: (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 3 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11. 2002 B. Groundwater Subsurface water was not encountered in project test excavations and is not expected to impact site development. However, based on our experience with similar geotechnical conditions, prolonged rainfall or excessive up-slope irrigation practices may result in periodic seepage along the base of planned cut embankments. The use of subsurface drains or retaining walls provided with backdrains may be appropriate as a means of protecting nearby improvements. As with all graded hillside properties, the proper control of surface drainage remains a critical factor in the continued stability of the property. Ponding should not be allowed at the lot suri^aces, and irrigation waters should be held to a minimum. C. Slope Stability Landslides or other forms of slope instability are not indicated in surface exposures at the study sites, nor are they suggested in project exploratory test excavations. Noted bedrock exposures were chiefly massive or impacted by pooriy developed bedding conditions which were flat-lying. Inclined structure along which bedding failures could develop is not in evidence at the property. D. Faults / Seismicity Faults or significant shear zones are not indicated on or near proximity to the project site. As with most areas of California, the San Diego region lies within a seismically active zone; however, coastal areas of the county are characterized by low levels of seismic activity relative to inland areas to the east. During a 40-year period (1934-1974), 37 earthquakes were recorded in San Diego coastal areas by the California Institute of Technology. None of the recorded events exceeded a Richter magnitude of 3.7, nor did any of the earthquakes generate more than modest ground shaking or significant damages. Most of the recorded events occurred along various offshore faults which characteristically generate modest earthquakes. Historically, the most significant earthquake events which affect local areas originate along well known, distant fault zones to the east and the Coronado Bank Fault to the west. Based upon available seismic data, compiled from California VINJE6?MIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760} 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET, CARLSBAD, CALIFORNIA PAGE 4 FEBRUARY 11, 2002 Earthquake Catalogs, the most significant historical event in the area of the study site occurred in 1800 at an estimated distance of 10 miles from the project area. This event, which is thought to have occurred along an off-shore fault, reached an estimated magnitude of 6.5 with estimated bedrock acceleration values of 0.097g at the project site. The following list represents the most significant faults which commonly impact the region. Estimated ground acceleration data compiled from Digitized California Faults (Computer Program EQFAULT VERSION 3.0 UPDATE) typically associated with the fault is also tabulated. r--. : . TABLE 1 Fault Zone Distance from Site Maximum Probable Acceleration (R.H.) Elsinore fault 24 miles 0.093g San Jacinto fault 47 miles 0.069g Coronado Bank fault 21 miles 0.140g Newport - inglewood fault 6 miles 0.1 68Q The location of significant faults and earthquake events relative to the study site are depicted on a Fault - Epicenter Map attached to this report as Plate 10. More recently, the number of seismic events which affect the region appears to have heightened somewhat. Nearly 40 earthquakes of magnitude 3.5 or higher have been recorded in coastal regions between January, 1984 and August, 1986. Most ofthe earthquakes are thought to have been generated along offshore faults. For the most part, the recorded events remain moderate shocks which typically resulted in low levels of ground shaking to local areas. A notable exception to this pattern was recorded on July 13, 1986. An earthquake of magnitude 5.3 shook County coastal areas with moderate to locally heavy ground shaking resulting in $700,000 in damages, one death, and injuries to 30 people. The quake occurred along an offshore fault located neariy 30 miles southwest of Oceanside. A series of notable events shook County areas with a (maximum) magnitude 7.4 shock in the early morning of June 28, 1992. These quakes originated along related segments of the San Andreas Fault approximately 90 miles to the north. Locally high levels of ground shaking over an extended period of time resulted; however, significant damages to local structures were not reported. The increase in earthquake frequency in the region remains a subject of speculation among VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET, CARLSBAD, CALIFORNIA PAGE 5 FEBRUARY 11. 2002 geologists; however, based upon empirical information and the recorded seismic history of County areas, the 1986 and 1992 events are thought to represent the highest levels of ground shaking which can be expected at the study site as a result of seismic activity. In recent years, the Rose Canyon Fault has received added attention from geologists. The fault is a significant structural feature in metropolitan San Diego which includes a series of parallel breaks trending southward from La Jolla Cove through San Diego Bay toward the Mexican border. Recent trenching along the fault in Rose Canyon indicated that at that location the fault was last active 6 000 to 9,000 years ago. Thus, the fault is classified as "active" by the State of California which defines faults that evidence displacement in the previous 11 000 years as active. More active faults (listed on the preceding page) are considered most likely to impact the region during the lifetime of the project. The faults are periodically active and capable of generating moderate to locally high levels of ground shaking at the site. Ground separation as a result of seismic activity is not expected at the property. ,. , , ^,>,:.;;•, - , ' - For design purposes, site specific seismic parameters were determined as part of this investigation in accordance with the Uniform Building Code. The following parameters are consistent with the indicated project seismic environment and may be utilized for project design work: , ; -•"''••^ TABLE 2 .v..-'v--;/? Site Soil Profile Type Seismic Zone Seismic Zone Factor Seismic Source Type Seismic Response Coefficients Site Soil Profile Type Seismic Zone Seismic Zone Factor Seismic Source Type Na Nv Ca Cv Ts To Sc 4 0.4 B 1.0 1.1 0.40 0.60 0.600 0.120 Acoordina to Chapter 16, Division IV of the 1997 Uniform Buildinq Code E. Geologic Hazards Slope instability, faults or other notable geologic hazards are not indicated at the project sites. The most significant hazard which could impact the area will be associated with moderate to locally high levels of ground movement related to periodic seismic activity generated along distant active faults. Liquefaction or other related ground failures are not anticipated at the property. VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fox (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET CARLSBAD. CALIFORNIA PAGE 6 FEBRUARY 11. 2002 F. Laboratory Testing / Results ^ Earth deposits encountered in our exploratory test excavations were closely examined and sampled for laboratory testing. Based upon our test trench data and field exposures, site soils have been grouped into the following soil types: TABLE 3 Soil Type Description 1 brown silty sand with trace ciay (fill) 2 tan fine to coarse sand (bedrocl<) 3 red brown fine to medium sand (fill/terrace deposit) 4 gray claystone with intermixed sandstone (bedrocl<) The following tests were conducted in support ofthis investigation: 1- Maximum Dry Densitv and Optimum Moisture Content: The maximum dry density and optimum moisture content of Soil Types 1 and 3 were determined in accordance with ASTM D-1557. The test results are presented in Table 4. " - ' ' •••"^^ TABLE 4 Location Soil Type IViaximum Dry Density (Ym-pcf) Optimum IWoisture Content (a)opt-%) B-1 @ 5' 1 132.3 11.3 T-3 4' 3 131.4 10.3 Moisture-Density Tests: In-place dry density and moisture content of representative soil deposits beneath the site were determined from relatively undisturbed chunk and ring samples using the water displacement and weights and measurements test methods. The test results are presented in Table 5 and tabulated on the attached Test Trench Logs and Boring Logs VINJEiSfMIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET. CARLSBAD. CALIFORNIA PAGE 7 FEBRUARY 11. 2002 TABLE 5 Sample Location Soil Type Field IVIoisture Content (w-%) Field Dry Density (Yd-pcf) IVlax. Dry Density (Ym-pcf) Ratio Of In-Place Dry Density To Max. Dry Density* (Yd/Ym X 100) T-1 @ 7' 2 5.4 123.2 - T-2 (g 3' 1 6.5 104.7 132.3 79.1 T-2 (g 8' 2 7.0 109.8 -_ T-3 @ 4' 3 2.1 117.7 131.4 89.6 T-4 @ 2' 3 4.7 116,4 131.4 88.6 T-4 (g 4' 3 3.8 121.8 131.4 92.7 T-5 @ 5' 4 10.5 122.4 -_ T-5 @ 6' 2 11.5 120.7 -_ T-6 (g 5' 3 4.6 106.6 131.4 81.1 B-1 (g 14' 3 9.9 120.0 131.4 91.3 B-2 (g 3' 1 4.5 107.9 132.3 81.6 B-2 (g 17' 3 2.6 115.1 131.4 87.6 * Designated as relative compaction for structural fills. Required relative compaction for structurai fill is 90% or qreater 3- Expansion Index Test: Two expansion index tests were performed on representative samples of Soil Types 1 and 3 in accordance with the Uniform Building Code Standard 18-2. The test results are presented in Table 6. TABLE 6 Sample Location Soil Type Remolded a)(%) Saturation (%) Saturated CO (%) Expansion Index (El) Expansion Potential T-3 (g 4' 3 ----non-expansive B-1 @ 5' 1 8.9 50.2 16.5 16 very low (w) = moisture content in percent VINJE <S? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fox (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET, CARLSBAD, CALIFORNIA PAGE 8 FEBRUARY 11, 2002 Direct Shear Test: Two direct shear tests were performed on representative samples of Soil Types 1 and 3. The prepared specimens were soaked overnight, loaded with normal loads of 1, 2, and 4 kips per square foot respectively, and sheared to failure in an undrained condition. The test results are presented in Table 7. TABLE 7 Wet Angle of Apparent Sample Soil Sample Density Int. Fric. Cohesion Location Type Condition (Yw-pcf) (cD-Deg.) (c-psf) T-3 (g 4" 3 remolded 129.8 33 50 B-1 (g 5' 1 remolded 132.0 32 136 VI. CONCLUSIONS i , . ^ ^^^^^^^^^^^^^^^ - :^ ' Based upon the foregoing investigation, development of the study lots substantially as proposed, is feasible from a geotechnical viewpoint. Hillside terrain at the property is geologically stable and expected to perform well in support ofthe planned structures and improvements. Adverse geologic conditions or difficult grading problems are not indicated at the site. The following conditions are unique to the property and will most impact its development and associated costs from a geotechnical viewpoint: * Planned building areas ofthe two lots are mantled by undocumented fill soils which are not presently suitable for the support of improvements. Removal and recompaction of the existing site fills and upper weathered soft portions of terrace , ^ deposits will be necessary in order to construct a stable ground for the support of the proposed structures and improvements. Added removals of cut ground will also be necessary in the case of cut/fill pads which expose bedrock/terrace units so that uniform soil conditions are created throughout the buildings and improvement surfaces. Excavation difficulties or special grading problems are not anticipated. ; * Underlying bedrock and terrace deposit are predominantly dense and stable units which will provide good support for planned improvements and engineered fill sections. However, underlying terrace deposits locally occur in a weathered soft condition near the surface and should be removed and recompacted as part ofthe project remedial grading operations as recommended below. VINJE(S'MIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 9 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 * On-site natural terrain and bedrock units are expected to be geologically stable. Landslides or other forms of slope instability are not in evidence at the site and are not expected to impact the area. * Project excavations and removals will predominantly generate good quality sandy fills. However, existing site fills includes some asphalt and organic matter which should be selectively separated and removed from the new project fills. * Site soils are granular, non-expansive to very low expansive sandy deposits which work well in compacted fills. Based upon the anticipated grading scheme, finish grade soils are expected to consist of silty sand deposits (SM) with very low expansion potential (El less than 21). Actual classification and expansion characteristic of finished grade soil mix can only be provided in the final as-graded compaction report based on appropriate testing. * The overall stability of graded building surfaces developed over sloping terrain is most dependent upon adequate keying and benching of fill into the undisturbed bedrock during the grading operations. At the project site, added care should be given to proper construction of keyways and benching during regrading. * Natural groundwater is not expected to impact the project development or the long term stability of the developed site. However, the use of subdrains may be appropriate along the toe of graded cut slopes in the improvement areas to prevent potential seepage from up-slope rain and irrigation water as determined in the field by the project geotechnical consultant during construction. All site retaining and building basement/stem walls over 2 feet high maximum should be provided with a back drainage system. * Adequate site surface drainage control is a critical factor in the future stability of the developed property. * Liquefaction and seismically induced settlements will not be factors in the development of the proposed structures and improvements, provided our soil treatment recommendations are implemented during the grading operations. * Post construction total and differential settlements after building construction are not expected to be factors in the development of the project site, provided our remedial grading and foundation recommendations are implemented during the construction phase of the project. VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588^0/^ PAGE 10 FEBRUARY 11. 2002 * soil collapse will not be a factor in development of the study site, provided our recommendations for site development are followed. VII. RF^<^MMFNDATIONS The fonowing recommendations are Spring the at the project Site -'^J^^^f^'^^^J^'^^^^ .e a'ppropriate and <^n be ;rS"Man^^v1et ph^^^ final grading and building plans are ava.lable. A. rtrariinq and Earthworks The planned construction - ^g^dtfplX°^^^^^^^^ and i%rrnsr;i«cto.^^^^^^^^^^^^ sections: . ^. • « »nH ttnibbina- Existing vegetation, deleterious materials and debris grading. A rr«,.nH Treatment- The most effective soil improvement • wmmmm herein, and placed ^a^f ^^TtSlS nf pelete^^^^^^ emending the a minimum «'!f' ?om the outside perimeter of the planned =y, anTon™rade im™n.s may be adequate unless otherwise specified in the field. ruMirAJ INVESTIGATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET, CARLSBAD, CALIFORNIA PAGE 11 FEBRUARY 11, 2002 Typical removal depths in the vicinity of individual exploratory test sites are shown in Table 8. The tabulated values are subject to changes by the project geotechnical consultant in the field. Locally deeper removals may be necessary based on the actual field exposures and should be anticipated. TABLE 8 Location Total Deptii (ft) Estimated Deptfi to Ground- water (ft) Estimated Removal Depths (ft) CbminiBiitd.. T-1 9' n/e 3' southern lot, cut slope areas, depth of cut may govern, existing fill contains asphalt debris. T-2 9' n/e T southern lot, building pad areas. T-3 6' n/e 2' northern lot, cut slope areas, depth of cut may govern, existing fill contains asphalt debris/organic. T-4 6' n/e 3' northern lot, building pad areas. T-5 6'-8' n/e 3' southern lot, building pad areas. T-6 n/e 5' northern lot, building pad areas. B-1 25' n/e 13' southern lot, building pad areas. B-2 26' n/e 11' northern lot, building pad areas. 1. All depths are measured from the existing ground levels. 2. Actual depths may vary at the time of construction based on seasonal conditions and actual subsurface exposures. 3. Bottom of all removals should be prepared and recompacted as directed in the field. 4. In the parking, driveway and drive lane areas, removals will consist of depths to firm native ground or 1-foot below the deepest utility, or 3 feet but not less than 1-foot minimum as directed in the field. 5. Exploratory trenches excavated in connection with our study at the indicated locations were bacl<filled with loose and uncompacted deposits. The loose/uncompacted backfill soils within these trenches shall also be re-excavated and placed back as properly compacted fills as a part of the project grading operations. 6. n/e = not encountered. Cut/Fill Transition: Ground transition from excavated cut to placed fill should not be permitted underneath the proposed structures and improvements. Transition areas will require special treatment. The cut portion of the cut/fill pads plus 10 feet, where possible, should be undercut to a sufficient depth to VINJE(^MIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, Cali/bmia 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET, CARLSBAD. CALIFORNIA PAGE 12 FEBRUARY 11,2002 provide for a minimum of 3 feet of compacted fill mat below rough finish grades, or at least 12 inches of compacted fill beneath the deepest footing whichever is more. In the roadways, driveway, parking and on-grade slabs/improvement transition areas, there should be a minimum of 1-foot of compacted soils below rough finish subgrade. 1 Temporary Construction Slopes: Temporary construction slopes less than 12 feet in maximum height and exposing competent bedrock/terrace units may be constructed at near vertical gradients. Near vertical construction slopes less than 12 feet in maximum height will be grossly stable for temporary conditions. Geotechnical field inspections of the construction slopes by the project geotechnical consultant will be necessary during the gradmg and wal construction operations. Safety requirements enforced by CAL-OSHA and local governing agencies for open excavations also apply. 5 Fill Materials and Compaction: Soils generated from the on-site removals are sandy materials suitable for reuse as new compacted site fills. Asphalt debns organic and trash shall not be allowed in compacted fills. The indicated asphalt debris and organic should be selectively separated and removed from the on- site fills or contaminated soils may be exported from the site. Uniform bearing soil conditions should be constmcted atthe site by the grading operations Site soils should be adequately processed, thoroughly mixed, moisture conditioned to near optimum moisture levels, placed in thin uniform horizontal lifts and mechanically compacted to a minimum of 90% of the corresponding laboratory maximum dry density per ASTM D-1557, unless othenwise specified. 6 Permanent Graded Slopes: Project graded cut-fill slopes should be programmed for 2:1 gradients maximum. Graded slopes constructed at 2:1 gradients will be grossly stable with respect to deep seated and surficial failures forthe indicated design maximum vertical heights. All fill slopes shall be provided with a lower keyway. The keyway should maintain a minimum depth of 2 feet into the competent bedrock with a minimum width of 12 feet as approved by the project geotechmcal engineer or his designated representative. The keyway should expose competent bedrock throughout with the bottom heeled back a minimum of 2% mto the natural hillside and inspected and approved by the project geotechnical engineer. Additional level benches should be constructed into the natural hillside as the VINJE . MIDDLETON ENQINEER INQ,INC24^^ — — ^ PFRC TESTING ENVIRONMENTAL INVESTIGATIONS QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTING PERC TESTING PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 13 4588 ADAMS STREET. CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 fill slope construction progresses. Fill slopes should also be compacted to 90% (minimum) ofthe laboratory standard out to the slope face. Over-building and cutting back to the compacted core, or backrolling at a minimum of 4-foot vertical increments and "track-walking" at the completion of grading is recommended for site fill slope construction. Geotechnical engineering inspections and testing will be necessary to confirm adequate compaction levels within the fill slope face. Cut slopes should be inspected and approved by the project geotechnical consultant during the grading for confirming stability. Additional recommendations, if it becomes necessary, should be provided in the field based on the actual exposures. 7. Wall Back and Slope Toe Drainage Systems: A Wall backdrain system should be constructed behind the proposed site retaining and building/basement walls. The wall backdrain system should consist of a minimum 18-inches wide trench excavated to the depths of the wall foundation level with a minimum 4-inch diameter. Schedule 40 (SDR 35) perforated pipe surrounded with a minimum of 3 cubic feet per foot of %-crushed rocks wrapped in filter fabric (Mirafi 140 N), or Caltrans Class 2 permeable aggregate installed at suitable elevations to allow for adequate fall via a non-perforated solid pipe to an approved outlet. Filter fabric can be eliminated if Class 2 permeable material is used. Typical wall backdrain system is depicted on the attached Plate 11. Provide appropriate waterproofing as indicated on the project architectural drawings. A toe drainage system may also be required at the base of the project cut slopes. Appropriate recommendations should be given by the project geotechnical engineer in the field at the time of construction, based on actual subsurface exposures and exposed slope face conditions. 8. Drainage and Erosion Control: A critical element to the continued stability of the building pads and slopes is an adequate surface drainage system and protection of the slope face. This can most effectively be achieved by appropriate vegetation cover and the installation of the following systems: * Drainage swales should be provided at the top and toe of the graded slopes, per the project civil engineer design. VINJEiffMIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS I ^ PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 14 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11. 2002 * Building pad surface run-off should be collected and directed away from the planned buildings and improvements to a selected location in a controlled manner. Area drains should be installed. * The finished slope should be planted soon after completion of grading. Unprotected slope faces will be subject to severe erosion and should not be allowed. Over-watering ofthe slope faces should also not be allowed. Only the amount of water to sustain vegetation should be provided. 9. Engineering Inspections: All grading operations including removals, suitability of earth deposits used as compacted fill, and compaction procedures should be continuously inspected and tested by the project geotechnical consultant and presented in the final as-graded compaction report. The nature of finished subgrade soils should also be confirmed in the final compaction report at the completion of grading. Geotechnical engineering inspections shall include, but not limited to the following: * Initial Inspection - After the grading/brushing limits have been staked, but before grading/brushing starts. * Keyway/bottom of over-excavation inspection - After the natural ground or bedrock is exposed and prepared to receive fill, but before fill is placed. * Cut slope/excavation inspection - After the excavation is started, but before the vertical depth of excavation is more than 5 feet. Local and CAL-OSHA safety requirements for open excavations apply. * Fill/wall backfill inspection - After the fill/wall backfill placement is started, but before the vertical height of fill/backfill exceeds 2 feet. A minimum of one test shall be required for each 100 lineal feet maximum with the exception of wall backfills where a minimum of one test shall be required for each 25 lineal feet maximum. Wall backfills should also be mechanically compacted to a minimum of 90% compaction levels. Finish rough and final pad grade tests shall be required regardless of fill thickness. * Foundation trench inspection - After the foundation trench excavations, but before steel placement. VINJEi^MIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIGATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIGATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 15 4588 ADAMS STREET. CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 * Foundation bearing/slab subgrade soils inspection - Within 72 hours prior to the placement of concrete for proper moisture and specified compaction levels. * Geotechnical foundation/slab steel inspection - After steel placement is completed, but 24 hours before the scheduled concrete pour. * Subdrain/wall backdrain inspection - After the trench excavations, but during the actual placement. All material shall conform to the project material specifications and approved by the project geotechnical engineer. * Underground/utility trench inspection - After the trench excavations, but before installation ofthe underground facilities. Local and CAL-OSHA safety requirements for open excavations apply. Inspection of the trench bottom and pipe bedding may also be required by the project geotechnical engineer. * Underground/utility trench backfill inspection - After the backfill placement is started above the pipe zone, but before the vertical height of backfill exceeds 2 feet. Testing of the backfill within the pipe zone may also be required by the governing agencies. Pipe bedding and backfill materials shall conform to the governing agencies requirements and project soils report if applicable. All trench backfills shall be compacted to a minimum of 90% compaction levels unless othenwise specified. Utility trenches over 12 inches deep maximum under the interior floor slabs should also be mechanically compacted and tested for a minimum of 90% compaction levels. Flooding or jetting techniques as a means of compaction method shall not be allowed. * Pavement/improvements subgrade and basegrade inspections - Within 72 hours prior to the placement of concrete or asphalt for proper moisture and specified compaction levels. B. Foundations and Interior Floor Slabs The following preliminary recommendations are consistent with very low expansive (El less than 21) silty sand (SM) foundation bearing soil. Final foundation and slab design will depend on expansion characteristics of finish grade soils and the actual fill differential thickness underneath the proposed buildings. All recommendations should be confirmed and/or revised as necessary in the rough grading compaction report based on-site as-graded geotechnical conditions and actual testing of the foundation bearing earth materials. Individual building sites may require specific VINJEiSCMIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIGATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 16 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 foundation/slab design and may be anticipated. Additional specific recommendations may also be necessary and should be given at the time of the plan review phase when detailed grading and structural/architectural drawings are available: 1. Continuous wall foundations should be sized 15 inches wide and 18 inches deep for single and two-story structures. Isolated pad footings should be at least 24 inches square and 12 inches deep. Footing depths are measured from the lowest adjacent ground surface, not including the sand/gravel beneath floor slabs. Exterior continuous footings should enclose the entire building perimeter. 2. Continuous interior and exterior foundations should be reinforced by at least 4- #4 reinforcing bars. Place a minimum of 2-#4 bars 3 inches above the bottom of the footing and a minimum of 2-#4 bars 3 inches below the top of the footing. Reinforcement details for spread pad footings should be provided by the project architect/structural engineer. 3. All interior slabs should be a minimum of 4 inches in thickness, reinforced with #3 reinforcing bars spaced 18 inches on center each way, placed mid-height in the slab. Slabs should be underiain by 4 inches of clean sand (SE 30 or greater) which is provided with a 6-mil plastic moisture barrier placed mid-height in the sand. In the case of good quality sandy subgrade soils, as approved by the project geotechnical engineer, the 6-mil plastic moisture barrier may be laid directly over the slab subgrade and covered with a minimum of 2 inches of clean sand (SE 30 or greater). 4. Provide "soft-cut" contraction/control joints consisting of sawcuts spaced 10 feet on center maximum each way for all interior slabs. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The sawcuts should be a minimum of 1-inch in depth but not to exceed 1 Vi-inches. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 5. Provide re-entrant corner reinforcement for all interior slabs. Re-entrant corners will depend on slab geometry and/or interior column locations. The attached Plate 12 may be used as a general guideline. VINJE <S? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 17 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 6. Foundation trenches and slab subgrade soils should be inspected and tested for proper moisture and specified compaction levels, and approved by the project geotechnical consultant within 72 hours prior to the placement of concrete. C. Exterior Concrete Slabs / Flatworks 1. All exterior slabs (walkways, and patios) should be a minimum of 4 inches in thickness reinforced with 6x6/10x10 welded wire mesh carefully placed at mid- height in the slab. 2. Provide "soft-cut" contraction/control joints consisting of sawcuts spaced 10 feet on center (not to exceed 12 feet maximum) each way for all exterior slabs. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The sawcuts should be a minimum of 1-inch in depth but not to exceed IVi-inches. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. All exterior slab designs should be confirmed in the final as-graded compaction report. 4. Subgrade soils should be tested for proper moisture and specified compaction levels, and approved by the project geotechnical consultant within 72 hours prior to the placement of concrete. D. Soil Design Parameters The following preliminary soil design parameters are based on the tested representative samples of on-site earth deposits. All parameters should be re- evaluated when the characteristics of the final as-graded soils have been specifically determined: * Design wet density of soil = 129.8 pcf. * Design angle of internal friction of soil = 33 degrees. * Design active soil pressure for retaining structures = 38 pcf (EFP), level backfill, cantilever, unrestrained walls. * Design active soil pressure for retaining structures = 58 pcf (EFP), 2:1 sloping backfill surface, cantilever, unrestrained walls. * Design at-rest soil pressure for retaining structures = 59 pcf (EFP), non- yielding, restrained walls. VINJE <S? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIGATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 18 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 * Design passive soil pressure for retaining structures = 447 pcf (EFP), level surface at the toe. * Design coefficient of friction for concrete on soils = 0..39. * Net allowable foundation pressure for on-site compacted fills (minimum 15 inches wide by 18 inches deep footings) = 2000 psf. * Allowable lateral bearing pressure (all structures except retaining walls) for on- site compacted fill = 200 psf/ft. Notes - * Use a minimum safety factor of 1.5 for wall over-turning and sliding stability. However, because large movements must take place before maximum passive resistance can be developed, a safety factor of 2 may be considered for sliding stability where sensitive structures and improvements are planned near or on top of retaining walls. * When combining passive pressures and frictional resistance, the passive component should be reduced by one-third. * The net allowable foundation pressure provided herein was determined for footings having a minimum width of 15 inches and a minimum depth of 18 inches. The indicated values may be increased by 20% for each additional foot of depth and 20% for each additional foot of width to a maximum of 3500 psf if needed. The allowable foundation pressures provided herein also applies to dead plus live loads and may be increased by one-third for wind and seismic loading. * The allowable lateral bearing earth pressures may be increased by the amount of the designated value for each additional foot of depth to a maximum of 1500 pounds per square foot. E. Asphalt and PCC Pavement Desiqn Specific pavement designs can best be provided at the completion of rough grading based on R-value tests of the actual finish subgrade soils; however, the following structural sections may be considered for cost estimating purposes only (not for construction): 1. A minimum section of 3 inches asphalt on 6 inches Caltrans Class 2 aggregate base may be considered for the on-site asphalt paving surfaces. Actual design will also depend on the design Tl and approval ofthe City of Carlsbad. VINJES-MIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 19 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11, 2002 Base materials should be compacted to a minimum of 95% of the corresponding maximum dry density (ASTM D-1557). Subgrade soils beneath the asphalt paving surfaces should also be compacted to a minimum of 95% ofthe corresponding maximum dry density within the upper 12 inches. 2. Residential PCC driveways and parking supported on non-expansive to very low expansive (El less than 21) granular subgrade soils should be a minimum of 5 inches in thickness, reinforced with #3 reinforcing bars at 18 inches on centers each way, placed mid-height in the slab. Subgrade soils beneath the PCC driveways and parking should be compacted to a minimum of 90% of the corresponding maximum dry density. Provide "soft-cut" contraction/control joints consisting of sawcuts spaced 10 feet on center (not to exceed 15 feet maximum) each way. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The softcuts should be a minimum of 1-inch in depth but not to exceed 1V4-inches. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipments across cuts for at least 24 hours. 3. Subgrade and basegrade soils should be tested for proper moisture and the specified compaction levels and approved by the project geotechnical consultant within 72 hours prior to the placement ofthe base or asphalt/PCC finish surface. 4. Base section and subgrade preparations per structural section design, will be required for all surfaces subject to traffic including roadways, travelways, drive lanes, driveway approaches and ribbon (cross) gutters. Driveway approaches within the public right-of-way should have 12 inches subgrade compacted to a minimum of 95% compaction levels, and provided with a 95% compacted Class 2 base section per the structural section design. Base section may not be required under curb and gutters, and sidewalks in the case of non-expansive subgrade soils (expansion index less than 21). Appropriate recommendations should be given in the final as-graded compaction report. F. General Recommendations 1. The minimum foundation design and steel reinforcement provided herein are based on soil characteristics and are not intended to be in lieu of reinforcement VINJE <S? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 20 4588 ADAMS STREET, CARLSBAD, CALIFORNIA FEBRUARY 11. 2002 necessary for structural consideration. All recommendations should be further evaluated in the site specific study for each individual lot, and confirmed by the project architect/structural engineer. 2. Adequate staking and grading control is a critical factor in properiy completing the recommended remedial and site grading operations. Grading control and staking should be provided by the project grading contractor or sun/eyor/civil engineer and is beyond the geotechnical engineering services. Inadequate staking and/or lack of grading control may result in unnecessary additional grading which will increase construction costs. 3. Footings located on or adjacent to the top of slopes should be extended to a sufficient depth to provide a minimum horizontal distance of 7 feet or one-third of the slope height, whichever is greater (need not exceed 40 feet maximum) between the bottom edge of the footing and face of slope. This requirement applies to all improvements and structures including fences, posts, pools, spas, etc. Concrete and AC improvements should be provided with a thickened edge to satisfy this requirement. 4. Expansive clayey soils should not be used for backfilling of any retaining structure. All retaining walls should be provided with a 1:1 wedge of granular, compacted backfill measured from the base of the wall footing to the finished surface. 5. All underground utility trenches should be compacted to a minimum of 90% of the maximum dry density of the soil unless othenwise specified. Care should be taken not to crush the utilities or pipes during the compaction of the soil. Non-expansive, granular backfill soils should be used. 6. Site drainage over the finished pad surfaces should flow away from structures onto the street in a positive manner. Care should be taken during the construction, improvements, and fine grading phases not to disrupt the designed drainage patterns. Rooflines ofthe buildings should be provided with roof gutters. Roof water should be collected and directed away from the buildings and structures to a suitable location. Consideration should be given to adequately damp-proof/waterproof the basement walls/foundations and provide the planter areas adjacent to the foundations with an impermeable liner and a subdrainage system. VINJE 6? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, Caii/brnia 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 21 4588 ADAMS STREET. CARLSBAD. CALIFORNIA FEBRUARY 11. 2002 7. Final plans should reflect preliminary recommendations given in this report. Final foundations and grading plans may also be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation' report outlined herein. More specific recommendations may be necessary and should be given when final grading and architectural/structural drawings are available. 8. All foundation trenches should be inspected to ensure adequate footing embedment and confirm competent bearing soils. Foundation and slab reinforcements should also be inspected and approved by the project geotechnical consultant. 9. The amount of shrinkage and related cracks that occurs in the concrete slab- on-grades, flatworks and driveways depend on many factors, the most important of which is the amount of water in the concrete mix. The purpose of the slab reinforcement is to keep normal concrete shrinkage cracks closed tightly. The amount of concrete shrinkage can be minimized by reducing the amount of water in the mix. To keep shrinkage to a minimum, the following should be considered: * Use the stiffest mix that can be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical. For example, concrete made with %-inch maximum size aggregate usually requires about 40 Ibs more (nearly 5 gal.) water per cubic yard than concrete with 1-inch aggregate. * Cure the concrete as long as practical. The amount of slab reinforcement provided for conventional slab-on-grade construction considers that good quality concrete materials, proportioning, craftsmanship, and control tests where appropriate and applicable are provided! 10. A preconstruction meeting between representatives ofthis office, the property owner or planner, the grading contractor/builder and the city inspector, is recommended in order to discuss grading/construction details associated with site development. VINJE 6? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS QRADINQ SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIGATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 22 4588 ADAMS STREET, CARLSBAD. CALIFORNIA FEBRUARY 11, 2002 VIII. LIMITATIONS The conclusions and recommendations provided herein have been based on available data obtained from pertinent reports and plans, subsurface exploratory excavations as well as our experience with the soils and formational materials located in the general area. The materials encountered on the project site and utilized in our laboratory testing are believed representative of the total area; however, earth materials may vary in characteristics between excavations. Of necessity we must assume a certain degree of continuity between exploratory excavations and/or natural exposures. It is necessary, therefore, that all observations, conclusions, and recommendations be verified during the grading operation. In the event discrepancies are noted, we should be contacted immediately so that an inspection can be made and additional recommendations issued if required. The recommendations made in this report are applicable to the site at the time this report was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. It is almost impossible to predict with certainty the future performance of a property. The future behavior of the site is also dependent on numerous unpredictable variables, such as earthquakes, rainfall, and on-site drainage patterns. The firm of VINJE & MIDDLETON ENGINEERING, INC., shall not be held responsible for changes to the physical conditions of the property such as addition of fill soils, added cut slopes, or changing drainage patterns which occur without our inspection or control. The property owner(s) should be aware that the development of cracks in all concrete surfaces such as floor slabs and exterior stucco are associated with normal concrete shrinkage during the curing process. These features depend chiefly upon the condition of concrete and weather conditions at the time of construction and do not reflect detrimental ground movement. Hairiine stucco cracks will often develop at window/door corners, and floor surface cracks up to Ve-inch wide in 20 feet may develop as a result of normal concrete shrinkage (according to the American Concrete Institute). This report should be considered valid for a period of one year and is subject to review by our firm following that time. If significant modifications are made to your tentative development plan, especially with respect to the height and location of cut and fill slopes, this report must be presented to us for review and possible revision. VINJE (S? MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, Caii/bmia 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIGATIONS QRADINQ SUPERVISION PERCTESTINQ ENVIRONMENTAL INVESTIQATIONS PRELIMINARY GEOTECHNICAL INVESTIGATION 4588 ADAMS STREET, CARLSBAD, CALIFORNIA PAGE 23 FEBRUARY 11, 2002 Vinje & Middleton Engineering, Inc., warrants that this report has been prepared within the limits prescribed by our client with the usual thoroughness and competence of the engineering profession. No other warranty or representation, either expressed or implied, is included or intended. Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #02-108-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to you. VINJE & MIDDLETON ENGINEERING, INC. Ralph M. Vinje GE #863 Dennis Middleton CEG #980 ehdi S. S #46174 RMV/DM/SMSS/jt Distribution: Addressee (5) c:\jt\prelims.02\02-108-P CEG 960 ' ^ERTIFED I A- VINJE<S?MIDDLETONENQINEERINQ, INC. 2450 Vineyard Avenue, #102, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNlCAL INVESTIQATIONS GRADING SUPERVISION PERC TESTINQ ENVIRONMENTAL INVESTIQATIONS TOPO! map pnnted on 01/15/02 from "SanDiego,tpo" and "Untitled.tpg" 117°20'00" W WGS84 IWIS'OO" W 0 TH MN U7»20'00" W 0 WGS84 117°19'00" W 1 MILE MMOFEET 0 Piinted fiom TOPO! ©19»WildflowiPro(hKtiDiB(«Tyw.»OT» .com) GEOTECHNtOAL MAP Plate 2 4588 ADAMS STREET, CARLSBAD, CALIF. MB Location of test trencin ^ Loeatio n of test boring <D Depth of fill cover Geologic cross-section line Proposed slopes 1 Proposed buildings Scale: 1" 40' PRIMARY DIVISIONS CO _j o CO o UJ < CE LU CO ir < O o < QC UJ LL O LL _l < I 2 < I H m cc O z N < CO cc UJ ir < -J CO 53 o LL —I < I o CO Q UJ z < cc til QC z O u. 5 UJ a: UJ CO dm < > CO CO Z CO o < -; O I -J eg I- 5 IT m 2 < GRAVELS MORE THAN HALF OF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE SANDS MORE THAN HALF OF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE CLEAN GRAVELS (LESS THAN 5% FINES) GRAVEL WITH FINES CLEAN SANDS (LESS THAN 5% FINES) SANDS WITH FINES SILTS AND CLAYS LIQUID LIMIT IS LESS THAN 50% SILTS AND CLAYS LIQUID LIMIT IS GREATER THAN 50% GROUP SYMBOL GW GP GM GC SW SP SM SC ML CL OL MH CH OH SECONDARY DIVISIONS Well graded gravels, gravel-sand mixtures, little or no fines. Poorly graded gravels or gravel-sand mixtures, little or no fines. Silty gravels, gravel-sand-silt mixtures, non-plastic fines. Clayey gravels, gravei-sand-clay mixtures, plastic fines. Well graded sands, gravelly sands, little or no fines. Poorty graded sands or gravelly sands, little or no fines. Silty sands, sand-silt mixtures, non-plastic fines. Clayey sands, sand-ciay mixtures, plastic fines. Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clayey silts with sligfit plasticity. Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. Organic silts and organic silty clays of low plasticity. Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic slits. inorganic clays of higti plasficity, fat clays. Organic clays of medium to high plasticity, organic silts. HIGHLY ORGANIC SOILS PT Peat and other highly organic soiis. GRAIN'SIZES U.S. STANDARD SERIES SIEVE 200 40 10 CLEAR SQUARE SIEVE OPENINGS 3/4" 3" 12" SILTS AND CLAYS SAND FINE MEDIUM COARSE GRAVEL FINE COARSE COBBLES BOULDERS RELATIVE DENSITY CONSISTENCY SANDS, GRAVELS AND NON-PLASTIC SILTS BLOWS/FOOT VERY LOOSE 0 - 4 LOOSE 4 - 10 MEDIUM DENSE 10-30 DENSE 30 • 50 VERY DENSE OVER 50 CLAYS AND PLASTIC SILTS STRENGTH BLOWS/FOOT VERY SOFT 0 - 'A 0 - 2 SOFT VA • Ys 2 - 4 FIRM 'A - 1 4 - 8 STIFF 1 - 2 8-16 VERY STIFF 2 - 4 16 - 32 HARD OVER 4 OVER 32 1. Blow count, 140 pounci hammer falling 30 inches on 2 inch O.D. split spoon sampler (ASTM D-1586) 2. Unconfined compressive strength per SOILTEST pocket penetrometer CL-700 A = undisturbed chunk sample C = disturbed sample = sand cone test ^4Q = Standard Penetration Test (SPT) (ASTM D-1586) with blow counts per 6 inches II ^"^e = California Sampler with blow counts per 6 Inches VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Ave., #102 Escondido, CA 92029'-l229 KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System (ASTM D-2487) PROJECT NO. KEY I Date: 1-25-02 Logged by: SJM 1 DEPTH 1 (ft) SAMPLE T-1 uses SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) 1 DEPTH 1 (ft) SAMPLE DESCRIPTION uses SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) 1- 0 -FILL: Silty to clayey sand. Brown color. Moist. Loose. Asphalt debris. Lower contact dips approximately 45 degrees suthward. ST-1 SM/SC — 5 —\ TERRACE DEPOSIT: Sandstone. Fine to medium grained. Red brown color. Locally clayey. Cemented. Locally loose. Friable. Dark colored seams near surface. Dips 7 degrees southward. Likely cross- bedding. ST-3 sp/sc 1 - TERRACE DEPOSIT: Sandstone. Fine to medium grained. Red brown color. Locally clayey. Cemented. Locally loose. Friable. Dark colored seams near surface. Dips 7 degrees southward. Likely cross- bedding. ST-3 sp/sc 1 5.4 123.2 - 1-10- -15- \ BEDROCK: Sandstone. Fine to coarse grained. Brown to tan color. Weathered. Friable. Cemented. Massive. No apparent structure. Indistinct upper contact ST-2 SW 1 1-10- -15- \ End Test Trench at 9'. (No Caving. No Groundwater.) Date: 1-25-02 Logged by: SJM DEPTH (ft) SAMPLE T-2 DESCRIPTION USCS SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) 0 I- 5 • FILL: Silty sand. Fine to coarse grained. Brown color. Trace of ciay. Moderately dense. ST-1 SM 6.5 104.7 79.1 I-10 15- • BEDROCK: Sandstone. Fine to coarse grained. Tan color Moist. Weathered. Friable. Cemented. Massive. ST-2 SW 7.0 109.8 End Test Trench at 9.' (No Caving. No Groundwater.) VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 TEST TRENCH LOGS ADAMS STREET, CARLSBAD PROJECT NO. 02-108-P PLATE 3 T Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings I J Date: "••25-02 Logged by: SJM DEPTH (ft) SAMPLE T-3 uses SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) -0- ^ • y FILL: Silty sand. Fine to coarse grained. Brown color. Same gravel. Asphalt debris. Organic Material. Loose. Lower contact dips 19 degrees southward. ST-1 SM / \ • • FILL: Silty sand. Fine to coarse grained. Brown color. Same gravel. Asphalt debris. Organic Material. Loose. Lower contact dips 19 degrees southward. ST-1 SM / 2.1 117.7 89.6 \ • • TERRACE DEPOSIT: • —- * SP / 2.1 117.7 89.6 -10- -15- \ Sandstone. Fine to medium grained. Red brown. Locally trace of clay. Porous near upper contact Several cobbles and pebbles. Weathered. Friable. Cemented - locally weakly cemented. Massive. ST-3 • —- * SP / -10- -15- \ End Test Trench at 6'. (No Caving. No Groundwater.) Date: 1-25-02 Logged by: SJM DEPTH (ft) SAMPLE T-4 DESCRIPTION USCS SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) 0 5 - 10 -15 • • FILL: Silty sand. Fine to coarse grained. Brown color. Dry. Loose. ST-1 SM TERRACE DEPOSIT: Sandstone. Fine to medium grained. Red-brown color. Porous near upper contact Cemented - locally weakly cemented. Massive. Several cobbles at 3'. ST-3 SP 4.7 3.8 116.4 121.8 88.6 92.7 End Test Trench at 6'. (No Caving. No Groundwater.) 1 VINJE & MIDDLETON ENGINEERING, INC 1 2450 Vineyard Avenue, Suite 102 I Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 T€St TRENCH LOGS 1 VINJE & MIDDLETON ENGINEERING, INC 1 2450 Vineyard Avenue, Suite 102 I Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 ADAMS STREET, CARLSBAD 1 VINJE & MIDDLETON ENGINEERING, INC 1 2450 Vineyard Avenue, Suite 102 I Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 PROJECT NO. 02-108-P PLATE 4 1 T Sand Cone Test • Bulk Sample • Chunk Sample O Driven Rings I I I Date: 02-11-02 Logged by: SJM DEPTH (ft) SAMPLE T-5A (Slope Side) uses SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 -BEDROCK: Sandstone. Fine to coarse grained. Tan color. Weathered - highly weathered near surface. Friable. Cemented. ST-2 SW - 5 -• Claystone. Gray. Blocky. Well cemented. Some carbonate staining. Locally coarse sand intermixed. Upper and lower contacts horizontal and marked by gray stained sandstone. .«?T^ CL 10.5 122.4 - -• Sandstone. Fine to coarse grained. Tan color. Weathered. Friable. Cemented. Massive. ST-2 SW 1 11.5 120.7 - -10- - 15- \ Sandstone. Fine to coarse grained. Tan color. Weathered. Friable. Cemented. Massive. ST-2 SW 1 -10- - 15- \ End Test Trench at 8'. (No Caving. No Groundwater.) Date: 1-25-02 Logged by: SJM DEPTH (ft) SAMPLE T-5B (Pad Side) DESCRIPTION USCS SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) t- 0 FILL: Silty sand. Fine to coarse grained. Brown color. Moist Loose. Lower contact dips 25 degrees southward. ST-1 SM 5 -BEDROCK: Sandstone. Fine to coarse grained. Tan color. Weathered. Friable. Cemented. Massive. ST-2 SW End Test Trench at 6'. (No Caving. No Groundwater.) 10 15- VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 TEST TRENCH LOGS ADAMS STREET, CARLSBAD PROJECT NO. 02-108-P PLATE 5 T Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings I Date: 1-25-02 Logged by: SJM 1 DEPTH (ft) SAMPLE T-6 uses SYMBOL MOISTURE {%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) 1 DEPTH (ft) SAMPLE DESCRIPTION uses SYMBOL MOISTURE {%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) - 0 -FILL: Silty sand. Fine to coarse grained. Brown in color. Moist. Loose. Attitude of lower contact N25° 10°SE ST-1 SM - 5 -• . TERRACE DEPOSIT: Sandstone. Fine to medium grained. Red-brown color. Weathered. Friable. Weakly cemented. Locally loose. Moist. Massive. Becomes cemented at 5'. ST-3 SP 1 4.6 106.6 81.1 llllllllll llllllllll \ TERRACE DEPOSIT: Sandstone. Fine to medium grained. Red-brown color. Weathered. Friable. Weakly cemented. Locally loose. Moist. Massive. Becomes cemented at 5'. ST-3 SP 1 llllllllll llllllllll \ End Test Trench at SYi. (No Caving. No Groundwater.) 1 Date: Logged by: SJM DEPTH (ft) SAMPLE USCS MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) DEPTH (ft) SAMPLE DESCRIPTION SYMBOL MOISTURE (%) DRY DENSITY (pcf) RELATIVE COMPACTION (%) h - 5 - -10- - 15- VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 Office 760-743-1214 Fax 760-739-0343 TEST TRENCH LOGS ADAMS STREET, CARLSBAD PROJECT NO. 02-108-P PLATE 6 T Sand Cone Test Bulk Sample • Chunk Sample Q Driven Rings BORING LOG DEPTH FT SAMPLE Description USGS SYMBOL MOISTURE (%) DRY DENSITY (PCF) RELATIVE COMPACTION (%) - 0 -FILL: Silty sand. Brown color. Trace of clay. Moist SM - 5 -• ST-1 -10- 1 BEDROCK- -15-0 3,4 • Sandstone. Tan color Medium grained. Trace of clay. Some pebbles. Massive. Locally well- cemented. 9.9 120.0 91.3 -20- 25 Upper contact marked by 6" thick zone of dark brown sandy soil. Oriented N75E/16SE. Upper contact marked by 6" thick zone of dark brown sandy soil. Oriented N75E/16SE. At 20', sandstone is coarse grained. Remains massive. No apparent structure. ST-3 SP End Boring at 25'. -30- (No caving. No groundwater.) -35- Proiect: KELLY - ADAMS STREET. CARLSBAD Project No: 02-108-P Date Drilled 1-24-02 .Logged Bv: SJM Drill, Sample Method: Truck Mounted 24" Diameter Bucket Rig - 24 Ib Drive Bulk Sample Ring Sample SPT Sample Sand Cone Test PLATE 7 o i T Vinje & Middleton Engineering, Inc. BORING LOG . • B-2 DEPTH FT SAMPLE Description USGS SYMBOL MOISTURE (%) DRY DENSITY (PCF) RELATIVE COMPACTION (%) IIIIIII IIIIIII 0 2,4 FILL: Silty sand. Brown color. Trace of clay. Moist to dry. Lower contact dips 10° to southeast. SM 4.5 107.9 81.6 -10- ST-1 -15- 0 5,6H TERRACE DEPOSIT: Sandstone. Fine to medium grained. Red- brown color. Cemented. Moist. Friable. Massive. No apparent structure. Weekly cemented between 16' to 20'. SP 2.6 115.1 87.6 -20- Below 20', locally clayey. ST-3 -25- -End Boring at 26'. -30- (No caving. No groundwater.) -35- Proiect: KELLY - ADAMS STREET. CARLSBAD Bulk Sampie • Ring Sample O SPT Sampie || Sand Cone Test • Proiect No: 02-108-P Date Drilled 1-24-02 Loaaed Bv: SJM Bulk Sampie • Ring Sample O SPT Sampie || Sand Cone Test • Drill, Sample Method: Truck Mounted 24" Diameter Bucket Rig -24 ib Drive PLATE 8 Vinje & Middleton Engineering, Inc. -150 -IQO -50 GEOLOGIC CROSS-SECTION PLATE 9 Scale: 1"=40' •SN 1\ J I ..Z;v, ... 10 30 MILES —I FAULT - EPICENTER MAP SAN DIEGO COUNTY REGION INDICATED EARTHQUAKE EVENTS THROUGH 75 YEAR PERIOD (1900-1974) Map data is compiled from various sources including California Division of Mines and Geology, California Institude of.Technology and the National Oceanic and Atmospheric Administration. Map is reproduced from California Division of Mines and Geology, "Earthquake Epicenter Map of California; Map Sheet 39." Earthquake Magnitude , 4.0 TO 4.9 O 5.0 TO 5.9 O 6.0 TO 6.9 .... 7.0 TO 7.9 Fault. PROJECT: Job #02-108-P 4588 ADAMS STREET. CARLSBAD PLATE NO: 10 RETAINING WALL DRAIN DETAIL Typical - no scale drainage Granular, non-expansive backfill. Compacied. Waterproofing Perforated drain pipe Fitter Maferial. Crushed rock (wrapped in filter fabric) or Class 2 Permeable Material (see specifications below) v foott ng . •yp. Competent, approved soils or bedrock CONSTRUCTION SPECIFICATIONS: SPECIFICATIONS FOR CALTRANS CLASS 2 PERMEABLE MATERIAL (GR^1.025) U.S. STANDARD SIEVE SIZE ;1" : ; 3/4 3/8 No.4 m. 8 No, 30 No. 50 No. 20G % PASSING IDD 90-100 40-100 25H4D ; 18-33: 5-15:^: 0-7 0-3: Sand Equivalent > 75 1. Provide granular, non-expansive backfill soil in 1:1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. 2. Provide back drainage for wall to prevent build-up of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outlined below. 3. Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable outlet at minimum 1%. Provide VA" - VA' crushed gravel filter wrapped in filter fabric (Mirafi 140N or equivalent). Delete filter fabric wrap if Caltrans Class 2 permeable material is used. Compact Class 2 material to minimum 90% of laboratory standard. 4. Seal back of wall with waterproofing in accordance with architect's specifications • , ,• 5. Provide positive drainage to disallow ponding of water above wall. Lined drainage ditch to ^- minimum 2% flow away from wall is recommended. * Use IVi cubic foot per foot with granular backfill soil and 4 cubic foot per foot if expansive backflll soil is used VINJE & MIDDLETON ENGINEERiNG, INC. PLATE 11 ISOLATION JOINTS AND RE-ENTRANT CORNER REINFORCEMENT Typical - no scale RE-ENTRANT CORNER CRACK RE-ENTRANT CORNER—> REINFORCEMENT NO. 4 BARS PLACED 1.5 BELOW TOP OF SLAB NOTES: 1. Isolation joints around the columns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the corners of the isolation joints do not meet the contraction joints, radial cracking as shown in (c)may occur (reference ACI). 2. In order to control cracking at the re-entrant corners (±270° corners), provide reinforcement as shown in (c). 3. Re-entrant corner reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and/or structural engineer based upon slab geometry, location, and other engineering and construction factors. VINJE & MIDDLETON ENGINEERING, INC. PLATE 12