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MS 04-06; MAY MINOR SUBDIVISION; PRELIMINARY GEOTECHNICAL INVESTIGATION; 2003-10-17
Preliminary Geotechnical Investigation Proposed Two-Lot Residential Development El Camino Real, Carlsbad, California (A.P.N. #167-080-36) 01 October 17; 2003 Prepared For: Ms. MARY HUMPHREY 18627 Brookhurst Street, #332 Fountain Valley, California 92708 Prepared By: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Suite 102 Escondido, California 92029 Job #03-390-P I VINJE & MIDDLETON ENGINEERING, INC. I 2450 Vineyard Avenue Escondido, California 92029-1229 I Job #03-390-P Phone (760) 743-1214 Fax (760) 739-0343' October 17, 2003 I Ms. Mary Humphrey 18627 Brookhurst Street, #332 5 Fountain Valley, California 92708 ' I ' PRELIMINARY GEOTECHNICAL INVESTIGATION, ,PROPOSED TWO-LOT RESIDENTIAL I DEVELOPMENT, EL CAMINO REAL, CARLSBAD, CALIFORNIA (A.P.N. #167-080-36) Pursuant to your request, Vinje and Middleton Engineering, Inc., has completed the I 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 analyzes and provides conclusions and construction recommendations for the proposed development as understood. From a geotechnical engineering standpoint, it is our opinion that the site is suitable the proposed two-lot residential development and the associated improvements, provided the recommendations presented in this report are I incorporated into the design and construction of the project. , S The conclusions and recommendatiohs provided in r this study are consistent with the indicated 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. I Reference to our Job #03-390-P will help to expedite our response to your inquiries. I We appreciate this opportunity to be of service to you VINJE& MIDDLETON ENGINEERING, INC. S ' I ennis Middleton CEG#980 DM/it I TABLE OF CONTENTS PAGE NO. I. INTRODUCTION ..................................................... I II. SITE DESCRIPTION ................................................I III. PROPOSED DEVELOPMENT .........................................I IV. SITE INVESTIGATION ..............................................2 V. GEOTECHNICAL CONDITIONS ............................................2 Earth Materials ...................................................2 Groundwater and Surface Drainage .................................. 3 Slope Stability ..................................................3 Faults I Seismicity ...................................................3 Geologic Hazards .............................................. 6 Laboratory Testing I Results ........................................6 VI. CONCLUSIONS ..................................................9 VII. RECOMMENDATIONS .............................................10 Remedial Grading and Earthworks ...............................10 Foundations and Slab-on-Grade Floors ....................... 16 Exterior Concrete Slabs! Flatworks ..............................17 Soil Design Parameters .........................................18 Asphalt and PCC Pavement Design ...............................19 General Recommendations .......................................20 VIII. LIMITATIONS ......................................................23 TABLE NO. Fault Zone ........................................................... Site Specific Seismic Parameters .......................................2 SoilType ..............................................................3 Maximum Dry Density and Optimum Moisture Content ........................4 Moisture-Density Tests (Undisturbed Chunk Samples) ....................... 5 Expansion Index Test .....................................................6 Direct Shear Test .......................................................7 TABLE OF CONTENTS (continued) Grain Size Analysis .........................................................8 SulfateTest ............................................................9 Removals and Over-excavations .........................................10 PLATE NO. Regional Index Map ..................... . .................. . .............. I Preliminary Siting and Grading Study ....................................2 Geologic Cross-Section ................................................3 Test Trench Logs (with key) ..........................................4-6 Fault - Epicenter Map .................................................7 Retaining Wall Drain Detail ..............................................8 Isolation Joints and Re-entrant Corner Reinforcement ......................9 I. I PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED TWO-LOT RESIDENTIAL DEVELOPMENT EL CAMINO REAL, CARLSBAD, CALIFORNIA I. INTRODUCTION I The property investigated in this work includes partially deieIoped hillside terrain located, on the west side of El Camino Real approximately 650 feet south of Chestnut Avenue in - the City of Carlsbad. The property location is depicted on a Regional Index Map enclosed I with this report as Plate 1.. We understand that the property is planned for.a two-lot residential development with associated structures and improvements. Consequently, the purpose of this study was to determine soil and geotechnical conditions at the property and I evaluate their influence upon the planned construction. Geologic mapping, test trench digging, soil sampling and testing were among the activities conducted in conjunction with this effort which has resulted in the geotechnical development and, foundation I recommendations presented herein II.. SITE DESCRIPTION Existing topographic conditions and a preliminary development scheme are shown on a Preliminary Siting and Grading Study., provided by. Vista Engineering, Inc., included with I this report as Plate 2. The property is bordered by El Camino Real to the east residential properties to the south and west, and undeveloped terrain to the north. The largest site slope ascends approximately 25 feet on the west side of the existing pad 'onto off-site I terrain above. Slope gradients locally approach 1.5:1 (horizontal to vertical) at their steepest. Previous cut/fill grading in the westerly portion of the site resulted, in an existing nearly level pad area. The existing pad area extends, north into the adjacent property.. I Approximate limits of existing site fills associated with the grading are shown on Plate 2. Site drainage sheetflows in an easterly direction to El .Camino Real. Some minor erosion 1 . was noted in the existing fills and on the westerly graded slope. Elsewhere, excessive scouring or erosion from uncontrolled run-off is, not in evidence. PROPOSED DEVELOPMENT. We understand the study property, is planned for the support of two three-story dwellings. with associated structures and improvements as shown on Plate 2. The 'lower basement level for both dwellings will be entirely or partially subterranean. Basement retaining walls are incorporated into the designs to accommodate ground t'ransitioning and achieve final grades. A Geologic Cross-Section through the planned development is enclosed as*Plate 3. Minor to moderate cut grading is planned for the creation of new level building and basement pads Maximum 10 feet of cut excavations are anticipated in the proposed basement areas. , I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone.(760) 743.1214 Fax (760) 739.0343' (EOTECHNICAL INVESTI(ATIONS ' ' GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I F~ I I ''H I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 2 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 Pavement improvements consist of PCC driveways with longitudinal gradients that range from 10% maximum for the lower easterly dwelling to 20% maximum for the upper, westerly dwelling. Detailed building' plans are unavailable. However, it is anticipated that building construction will consist of a lower masonry block basement wall, and upper wood-frame and stucco structures supported on' shallow stiff continuous strip and spread pad concrete footings with slab-on-grade floor foundations. SITE INVESTIGATION Subsurface conditions at the site were chiefly determined by the excavation of 6 test trenches dug with a tractor-mounted backhoe. All trenches were logged by our' project geologist who also retained rock/soil samples for laboratory testing. Test trench locations are 'shown on Plate 2. Logs of the trenches are enclosed with this report as Plates 4-6. Laboratory test results are summarized in a following section. GEOTECHNICAL CONDITIONS The study property is underlain by formational bedrock units mantled by a modest cover of fill and topsoil. Terrace Deposits are exposed in the slope along the western margin of the site. Instability is not indicated at the property. A. Earth Materials Terrace Deposits Pleistocene age Terrace Deposits are exposed on an existing ascending slope along the west property margin. Exposures consist of dark- colored sandstone units that 'are typically fine to medium grained and massive. The sandstone was found in a cemented condition overall. Minor erosion mark portions of the slopeface. However, no evidence of shallow or-deep-seated slope instability is indicated. Formational Bedrock - The proposed building pad and improvement areas are underlain by Eocene age sedimentary bedrock units typically designated Santiago Formation. At the project site, the formational rock units typically consist of light- colored clayey to silty sandstone units with interbeds of cobble conglomerate and siltstone. As exposed in our test trenches, site formational units are weathered friable near the surface becoming cemented at depth. Project formational rocks are competent units that will adequately support the planned dwellings and improvements.' I I VINJE' & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 - EOTECHNICAL INVESTIGATIONS , GRADING SUPERVISION - I'ERC TESTING - ENVIRONMENTAL INVESTIGATION I I I I I I I I I I I I I I I 1 I PRELIMINARY GEOTECHNICAL INVESTIGATION . . PAGE 3 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 Topsoil - A modest cover of topsoil mantles much of the formational rock units at I .the study site. The topsoil typically consists-of sandy to clay-rich deposits that were found in loose to soft conditions near the surface becoming medium dense to stiff at depth. Project topsoils, as exposed in Test Trench 2 (T-2), reached a maximum I . thickness of 9 feet. . Fill - Artificial fills largely occupy the western portion of the subject site. Existing . site fill deposits consist of silty sands which were likely generated during thé.on-site I grading operations when the existing pad was created. Documentation for the fill placement is not available. Existing fills are anticipated to reach a maximum thickness of 5 feet. Estimated limits of the existing fill deposits at the site are I . shown on Plate 2. I . Details of the underlying earth materials at the site are presented on the enclosed Test Trench Logs, Plates 4-6. . 1 B. Groundwater and Surface Drainage - .. Groundwater conditions were not encountered in our test excavations to the depths .I explored and are not expected to impact site development. However, like all graded building sites, the proper control of surface drainage is an important factor in the continued stability of the property. Irrigation and meteoric water should not I be allowed to pond on lot surfaces and over-watering of site vegetation should be avoided. Project site and building basement retaining walls should be provided with adequate back drain systems. . . . I C Slope Stability I ' Landslides or other forms of geologic slope instability are not in evidence at the project site. The western site slope is performing well with no evidence of surficial - or deep-seated instability. Cemented Terrace Deposits exposed on the slope face and underlying formational rock materials are flat-lying to massive sandstone units which characteristically perform well with regard to gross stability and are expected to remain stable. fl . I - . . D. Faults I Seismicity . I . Faults or significant shear zones are not indicated on or near proximity to the project site I I I: VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION I'ERC TESTING ENVIRONMENTAL INVESTIGATION. TABLE I Fault Zone Distance From Site Maximum Probable Acceleration (R.H.) Rose Canyon fault . 6.0 miles ' 0.169g Newport-Inglewood fault ' 6.3 miles , 0.164g Coronado Bank fault ' 22.1 miles 0.136g Elsinorefáult 23.2 miles 0.112g I I I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 4 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003' As with most areas of California, the San Diego regiOn lies within a seismically I 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 I . 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 I occurred along various offshore faults which characteristically generate modest earthquakes. I 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 l Earthquake Catalogs, the most significant historical event in the area of the study site occurred .in 1800 at an estimated distance of 11 miles from the project area. This event, which is thought to have occurred along an off-shore fault, reached an I , estimated magnitude of 6.5'with estimated bedrock acceleration values of 0.91g, at the project site. The' following list represents the most significant faults which commonly impact the regior. Estimated ground acceleration data compiled from I . Digitized California Faults (Computer Program EQ FAULT VERSION 3.00 updated)' typically associated with the fault is, also tabulated. Li I Li LII The location of significant faults and earthquake events relative to the study site are depicted on a Fault - Epicenter Map enclosed with this report as Plate 7. 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. I VINJE & MIDDLETON ENGINEERINQ,INC. 2450 Vineyard Avenue Escondido, California 92029.1229,. Phone (760) 743.1214 • Fax (760) 739.0343 EOTECI-IN1CAL INVESTIGATIONS , GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 5 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER17, 2003 Most of the 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 nearly 30 miles southwest of Oceanside. I -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. I Locally high levels of ground shaking over an extended period of time resulted; however, significant damages to local structures were not reported. The increase I in earthquake frequency in the region remains a subject of speculation among. -.geologists; however, based upon empirical information and the recorded seismic history of County areas, the 1986 and 1992 events are thought to represent the I -- highest levels of ground shaking which can be expected at the study, site as a result of seismic activity. I 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 I -through San Diego Bay toward the Mexican border. Test trenchihg along the fault in Rose Canyon indicated that at that location the fault was last active 6,000 to 9,000 years ago. More recent work suggests that segments of the fault are , -younger having been last active 1000 - 2000 years ago. Consequently, the fault has been classified as -active and included within an Alquist-Priolo Special Studies'- -Zone established by the State of California. • I' Fault zones-tabulated in the preceding table are considered- most likely to impact - - the region of the study site during the lifetime of the project. The faults are I 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 • - I parameters are consistent with the indicated project seismic environment and may be utilized for project design work -- I -I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 EOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 6 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 TABLE2 — Site Soil Profile Type Seismic Zone Seismic Zone Factor Seismic Source Type Seismic Response Coefficients Na NV Ca Cv Ts To Sc 4 [ 0.4 B 1.0 I 1.0. I 0.40 I 0.57 I 0.569 I 0.114 According to Chapter 16, Division IV of the 1997 Uniform Building Code. I. .. E. Geologic Hazards I Geologic hazards are not presently indicated at the project site. Exposedslopes do not indicate gross geologic instability. The most significant geologic hazards at I the property will be those associated with ground shaking in the event of a major seismic event. Liquefaction or related ground rupture failures are not anticipated. I F. Laboratory Testing,! Results Earth deposits :encountered in- our exploratory test excavations were closely I .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 - pale brown silty fine to medium sand (Fill/Topsoil/Terrace Deposit) 2 dark brown to blue-grey sandy clay/clayey sand (Topsoil/Fill) - 3 tan to off-white silty sandstone, locally clayey (Formatibnal Rock) red-brown cobble conglomerate with clayey sand matrix (Formational Rock) 5 red-brown silty sand/cobble mix (Fill) I The following tests were conducted in support of this investigation - . 1. Maximum Dry Density and Optimum Moisture Content: The maximum dry - . density and optimum moisture content of Soil Types 2 and 3 were determined in accordance with ASTM D-1557. The test results are presented in Table 4. I I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 qEoTECHNICAL INVESTIGATIONS . GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 7 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 1 TABLE 4 Location Soil Type Maximum Dry Density (Ym-pcf) Optimum Moisture Content (wopt-%) 1-1 @4' 2 125.4 10.8 T-5@1' 3 123.4 12.4 2. Moisture-Density Tests (Undisturbed Chunk Samples): In-place dry density and moisture content of representative soil deposits beneath the site were I determined from relatively undisturbed chunk samples using the water displacement test method. The test results are presented in Table 5 and tabulated on the enclosed Test Trench Logs (Plates 4-6). I TABLES Sample Location Soil Type Field Moisture Content (w-%) Field Dry Density (Yd-pcf): Max Dry Density (Yrn-pcf)' Ratio Of In Place Dry Density To Max Dry Density* (YdiYm * 100) T-1 @1%' 2 9.3 111.6 125.4 89.0 T-1 @4' 2 13.2 109.5 125.4 87.3 - T-1 @ 7W 3 10.8 109.1 123.4 88.4 T-2@2' 1 1.6 104.0 - - T-2 @ 7' 2 8.8 105.2 125.4 83.9 T-2 @8W 2 7.2 114.0 125.4 90.9 T-4 @ 6'. 3 10.2 1266 123.4 100+ T-5 © 1' 2 9.4 126.7 123.4 100+ * Designated as relative compaction for structural fills. Required relative compaction for structural fill is 90% or greater. U 3. Expansion Index Test: Two expansion index tests were performed on I representative samples of Soil Types 2 and 3 in accordance with the Uniform Building Code Standard 18-2 The test results are presented in Table 6 I I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739.0343 QEOTECHNICAL INVESTIGATIONS . ()RADINQ SUPERVISION I'ERC TESTING ENVIRONMENTAL INVESTIGATION I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 8 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 TABLE6 - Sample Location Soil Type Remolded w (%) Saturation '(%) Saturated Expansion Index (El) Expansion Potential T-1 @4' 2 10.9, 49.8 20.2 45 low T-5@1' 3 10.4 508 18.8 7 very low (w) =-moisture content in percent. - I - 4. Direct ShearTest: Two direct shear tests were performed on representatiye samples of Soil Types 2 and 3. The prepared specimens, were soaked - overnight, loaded, with normal loads of 1, 2, and 4 kips per.'square foot I respectively, and sheared to failure in an undrained condition. The test results are presented in Table 7 I TABLE 7 Wet Angle of Apparentj Sample Soil Sample Density Int. Fric Cohesion Location Type Condition 'Yw-pcf (Deg.) (c-psf) T-1 @ 4', 2 remolded to 90% of Yd @ % wopt 123.9 30 245 T-5 1' 3 remolded to 90% of Yd @ % wopt 124.6 - 29 116 I - 5. Grain Size Analysis: Grain size analyzes were performed on representative samples of Soil Types 1, 2, and 3. The test results are presented in Table 8, I TABLE 8 Sieve Size - - 1h/2 I v,---I 3/4i1 F /2', I #4 1 410 I #20 I #40. I #200 Location Soil Type Percent Passing T-1 ©4' 2 100 100 100 100 100 98 85 64 32 T-2@2' 1 100 100 100 100 98 94 78 57 17 T-5@1' 3 100 100 100 100 100 95 73 59 44 I- - 6. Sulfate Test: One sulfate test was performed on a representative sample of I Soil Type 2 in accordance with the California Test 4,17.The test result is presented in Table 9 I I VINJE &-MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 EOTECHNICAL INVESTIGATIONS - GRADING SUPERVISION PERC TESTING - ENVIRONMENTAL INVESTIGATION I I PRELIMINARY GEOTECHNICAL. INVESTIGATION PAGE .9 EL CAMINO REAL, CARLSBAD, CALIFORNIA . OCTOBER 17, 2003 TABLE 9 I Amount Samp'e Location:[Soil of Water Soluble Sulfate (s04) Type ln.Soil(%:by:Weight) I T-i @ 4' I 2. I . . 0.013 I VI CONCLUSIONS Based upon the foregoing investigation, development of the project site substantially as I proposed, is feasible from a geotechnical viewpoint. The property is underlain by dense and stable formational bedrock .units which are mantled by a thin to modest section of I .loose to medium dense sandy to clayey fill / topsoils. Geotechnical factors presented below are unique to the project site and will influence I .grading procedures and associated development costs: * Instability is not indicated at the project site. Landslides or other forms of geologic I . instability within the onsite natural Terrace and Formational deposits are not indicated. . . . 1 * Modest basement excavations up to 10 feet maximum are planned to achieve lower level pad grade elevations. Elsewhere, relatively minor grade modifications are proposed to construct the planned design elevations. Unusual excavation I . difficulties within the onsite bedrock units are not.anticipated. * Site existing fills, topsoils, and upper weathered bedrock are not suitable for I .. .. support of the planned construction and improvements in their present condition. Removal, and recompaction of these deposits will be necessary in order to, construct stable ground surfaces suitable for the support of the proposed structures I .. and improvements. Added removals of cut ground will also be necessary in the case of cut/fill transition pads which expose bedrock units so that uniform bearing I . soil conditions are created throughout the building surfaces. * The overall stability of graded building pads developed over sloping terrain is most dependent upon adequate keying and benching of fill into the undisturbed bedrock. I during grading operations At the project site, added care should be given to proper construction of keyways and benching during grading I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 Phone (760) 743-1214 • Fax (760) 739.0343 EOTECI-INICAL INVESTIGATIONS ' . GRADING SUPERVISION I'ERC TESTING .. . . ENVIRONMENTAL INVESTIGATION PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 10 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 * Site soils are generally very low expansive silty sandy deposits. Some clay bearing soils with low expansive potential also occur at the site. Site potentially expansive soils may be first removed from the site in the case of an export operations. Potentially expansive soils may also be selectively buried in deeper fills or thoroughly mixed with 'an abundant very low expansive soils generated from the onsite excavations. * Based on the anticipated development scheme and grading recommendations given herein, finish grade soils are expected to consist chiefly of blayey'to silty sand deposits (SM/SC) with very low to low expansion potential (expansion index less than 51). Actual classification and expansion characteristic of finished gradesoil mix can only be provided in the final as-graded compaction report based on appropriate testing. * Groundwater conditions are not expected to impact grading activities or the long term performance of the developed areas. Adequate site surface drainage control,. however, remains a critical factor in the future stability of the developed property as planned. Well-constructed back drains should be provided behind the planned site and building basement retaining walls as recommended in the following sections. * Soil collapse, liquefaction and seismically induced settlements will not be a factor in thedevelpment of the project site. * Post construction settlements will not be a factor in construction of the planned new structures provided our remedial grading and foundation recommendations are followed. VII. RECOMMENDATIONS The following recommendations are provided based on the planned. construction as shown on the enclosed Plate 2. Added or modified recommendations may also be appropriate and can be provided at the final plan review phase when detailed construction plansare' finalized: ' A. Remedial Grading and Earthworks Cut/fill and remedial grading techn'iques should be used in order to achieve final design grades and improve soil I conditions beneath the new structures and improvements. All grading and project construction, should be completed in accordance with the Appendix Chapter 33 of the Uniform Building Code, ,City of I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECI-INICAL INVESTIGATIONS GRADING SUPERVISION • PERC TESTING ' ENVIRONMENTAL INVESTIGATION 7~ I I I I I I I I I I I I I I I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 11 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003' Carlsbad Grading Ordinances, the Standard Specifications for Public Works Construction, and the requirements of the following sections Clearing -and Grubbing: Existing vegetation, deleterious materials and debris should be removed from areas to receive new fills,, structures, and improvements plus 10 feet where possible, and as directed in the field. Prepared ground should be inspected and approved by the project geotechnical engineer or his designated field representative prior to the remedial grading work. Existing underground utilities inthe construction areas should be pot-holed, identified and marked prior to the actual work. Inactive lines shoUld be properly removed or abandoned as approved. Abandoned underground structures should also be removed and the generated. voids properly backfillèd with compacted soils in accordance with the recommendations provided herein. Removals and Over-excavations: Existing site loose to soft fills, topsoils, and upper weathered soft bedrock units at the project site should be removed to the underlying competent bedrock, or firm native ground as approved in the field by the project geotechnical engineer, and placed back as properly compacted fill. Typical removal depths in the vicinity, of individual exploratory test sites are shown in Table 10. Locally deeper removals may also be necessary based on the actual field exposures and should be anticipated: TABLE 10 Location Total Depth I (ft) Estimated Depth to Ground water I (ft) Estimated Removal Depths (ft) Comments .'. T-1 '- 8' We 2' Parcel B driveway areas T-2 10' ' We ' 8' Parcel A building pad areas T-3 ' 31/2' We 21/2' Parcel A building pad areas (see note 1) 1-4 8' We 5W slope areas, remove all existing fill/topsoil T-5 , 2' We 1' Parcel B building pad areas (see note 1) T-6 J 3' We 11/2' Parcel .B driveway areas Explanations: Depth of cut or undercut may govern. - All depths are measured fromthe existing ground levels. .. S VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739-0343 (EOTECHNICAL INVESTIGATIONS ' ' GRADING SUPERVISION ' PERC TESTING ENVIRONMENTAL INVESTIGATION -, I ' I ' I, 'I fl PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 12 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 Actual depths may vary at the time of construction based on actual subsurface exposures, Firm native ground is defined as undisturbed natural ground with in-place densities of 87% or greater. Bottom of all removals should be additionally prepared and recompacted as directed in the field. Exploratory trenches excavated in connection with our study at the indicated locations were backfilled 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. We = not encountered. 7 I. I I I I H H H I I I I I I 'Bearing Soils Transitioning: Project building/wall foundations should be uniformly supported on compacted fill soils. Foundation transitioning from compacted fills to cut ground or undisturbed Formational units should not be allowed. The cut or undisturbed ground portions of the bearing soils in the transition pads should be undercut a minimum of 3 feet below rough finish grades or 12 inches below the bottom of the deepest footing(s), whichever is more, and placed back as properly compacted fills. There should also be at least 12 inches of compacted subgrade soils below all onsite pavings and improvements. Temporary Construction Slopes: Temporary slopes, necessary for the project basement excavations may be constructed at near vertical gradients to a maximum of 5 feet. Construction slopes greater than 5 feet and less than 12 feet may be constructed at near vertical gradients within the lower 3 feet and /2:1 gradients maximum within the upper sections. The wall backfills should be properly benched and tightly keyed into the temporary slope as, the backfill placement progresses and as directed in the field by the project geotechnical consultant. Additional recommendations including flatter construction slopes and the need for temporary shoring should be given by the project geotechnical consultant at the time of earthwork operations based on actual field exposures. Fill Materials and Compaction: Soils generated 'from the removals of the existing fills and topsoils may be suitable for reuse as new compacted site fills provided all trash, debris and unsuitable materials are selectively removed and properly disposed of to the satisfaction of the project geotechnical engineer. Earth deposits at the site range from sandy soils to some potentially expansive clay-bearing materials Project potentially expansive soils may be first removed from the site in the case of an export operation. Select grading techniques may I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 (EOTECHNICAL INVESTIQATIONS . ' QRADIN( SUPERVISION I'ERC TEST:Nq , , ENVIRONMENTAL INVESTIGATION I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 13 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 I . also be considered to bury the site potentially expansive soils in deeper fills at I least 3 feet below rough finish grades or mix with an abundant very low, expansive soils generated from the onsite excavations. Typically, clayey-soils also require additional processing and moisture conditioning efforts in order to I manufacture a uniform soil mixture suitable for reuse as compacted fill. The clay-bearing soils should be moisture conditioned to slightly, (2% to 3%) above the optimum levels and compacted as specified. I Import soils, if required to complete grading or wall backfilling, should be very low expansive (expansion index less than 21) granular sandy deposits I inspected and approved by the project geotechnical consultant prior to delivery to the site. I Uniform bearing soil conditions should be constructed at the site by the grading operations. Site soils should be adequately processed, thoroughly mixed, moisture conditioned to slightly above the optimum moisture levels as directed I in the field, placed in thin uniform horizontal lifts and mechanically compacted to a minimum of 90% of the corresponding laboratory maximum dry density per I .ASTM D-1557, unless otherwise specified. A minimum of 90% compaction levels will be required for all structural fills and wall backfills. .In the improvement areas, fills should also be compacted to a I minimum 90% with the exception of the upper 12 inches under the asphalt paving surfaces where a minimum of 95% compaction levels will be required. I 6. Permanent Graded Slopes - Graded 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 for the anticipated design maximum vertical heights. . . I Fill slopes shall be provided with a lower Keyway. The Keyway should maintain a minimum depth of 2 feet into competent formational units with a minimum width of 12 feet as approved by the project geotechnical engineer or his I .. designated field representative. The Keyway should expose competent formationalunits throughout with the bottom heeled back a minimum of 2% into the natural hillside. Additional level benches should be constructed into the I natural hillside as the fill slope construction progresses. Fill slopes should also be compacted to 90% (minimum) of the, laboratory standard out to the slope face. Over-building and cutting back to the compacted core, or backrolling at a maximum of 4-foot vertical increments and "track-walking" at the completion i H I VINJE & MIDDLETON ENGINEERING, INC. 2450 'Vineyard Avenue, Escondido; California 920291229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIQATIONS . QRADINQ SUPERVISION I'ERC TESTING . - ENVIRONMENTAL INVESTIGATION I., I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 14 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17,2003 of grading, is recommended for site fill slope construction Geotechnical engineering inspections and testing will be necessary to confirm adequate I compaction levels within the fill slope face. 7. Shrinkage and Bulking: Based upon our analyzes, on-'site existing fills and topsoil deposits may be expected to shrink approximately 5% to 10%, and the soils generated from the excavations of the onsite Formational units may, be anticipated to bulk nearly 10% to 1.5% on a volume basis when compacted to at least 901/o of the corresponding maximum density. I Li] I, 1. I, I I I I . 1 I I , 8. Wall Back Drainage System: All site retaining and building basement walls, should be provided with adequate back drainage system. The wall back drain system should consist of a minimum 18-inches wide trench excavated to the depths of the wall foundation level. Aminimum 4-inch diameter, Schedule 40 (SDR 35) perforated pipe surrounded with a minimum of 2.25 cubic feet per foot of %-crushed rocks wrapped in filter fabric (Mirafi 140 N), or Caltrans Class 2 permeable aggregate should be used. The perforated drain pipe should be installed at suitable elevations to allow for adequate fall via non-perforated solid. pipe to an approved outlet. Filter fabric can be eliminated if Class 2 permeable material is used. Typical wall back drain system is depicted on the enclosed Plate 8. Appropriate waterproofing should be provided behind the walls. Protect pipe outlet as necessary. 9 Drainage and Erosion Control A critical element to the continued stability of the graded building pads is an adequate surface drainage system. This can most effectively be achieved by installation of appropriate surface drainage facilities. 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. Drainage swales should be provided at the top and toe of the slopes per project civil engineer design. Concrete brow ditches should be considered on the back side of basement walls. Area drains should be installed. . . Temporary erosion control facilities and silt fences should be installed during the construction phase periods and until landscaping is established as indicated and specified on the approved project erosion plans. 10. Engineering Inspections: All grading operations including removals, suitability of earth deposits. used as compacted fills, 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 remedial grading I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIQATIONS . GRADING SUPERVISION I'ERC TESTING ENVIRONMENTAL INVESTIGATION. I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 15 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 — . Geotechnical engineering inspections shall include but not limited to the I following: * Initial Inspection - After the grading I brushing limits have been staked but I . before grading / brushing starts. * Bottom of keyway/over-excavation inspection - After the natural ground or I . bedrock is exposed and prepared to receive fill but before fill is placed. * Excavation inspection - After the excavation is started, but before the vertical I . depth of excavation is more than 5 feet. Local and CAL-OSHA safety requirements for open excavations apply. . . I * Fill / backfill inspection - After the fill / backfill placement is started but before the vertical height of fill I backfill exceeds 2 feet. A minimum of one test shall be required for each 100 lineal feet maximum with the exception of wall I . backfills where a minimum of one test shall be required for each 25 lineal - feet maximum. Wall backfills shall also be mechanically compacted to at least 90% compaction levels unless otherwise specified. Finish rough and 1 final pad grade tests shall be required .regrdless of fill thickness. * Foundation trench inspection - After the foundation trench .excavations but I . . before steel placement. * Foundation bearing I slab subgrade soils inspection - Prior to the placement I of concrete for proper moisture and specified compaction levels. ' * Foundation I slab steel inspection - After steel placement is completed but .1 . . before the scheduled concrete pour. * Subdrain / wall back drain inspection - After the trench excavations, but during the actual placement. All material shall conform to the project 'material specifications and approved by the project soils engineer. * Underground . utility / plumbing trench inspection - After the trench excavations, but before placement of bedding, or installation of the underground facilities. Local and CAL-OSHA safety requirements for open excavations apply. Inspection of pipe bedding may also be required by the project geotechnical engineer.. Underground utility I plumbing trench backfill inspection,- After the backfill .placement is started above the pipe zone but before the vertical height of I I VINJE & MIDDLETON ENQINEERINQ, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 GEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION I'ERC TESTING ENVIRONMENTAL INVESTIGATION I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 16 EL CAMINO REAL, CARLSBAD CALIFORNIA OCTOBER 17, 2003 I backfill exceeds 2 feet. Testing of the backfill within the pipe zone may also I be required by the governing agencies. Pipe bedding and backfill materials shall conform to the governing agencies requirements and project soils report if applicable. IAll trench backfills shall be mechanically compacted to I a minimum of 90% compaction levels unless otherwise specified. Plumbing trenches over 12 inches deep maximum under the interior floor slabs should also be mechanically compacted and tested for a minimum of 90% I compaction levels. Flooding or jetting techniques as a means of compaction method shall not be allowed. I * Pavement/improvements subgrade and basegrade inspections - Prior to the placement of concrete or asphalt for proper moisture and specified compaction levels. B. Foundations and Slab-on-Grade Floors I . The following recommendations are consistent with very, low to low expansive (expansion index less than 51) clayey to silty sand (SM/SC) foundation bearing soil and site specific geotechnical conditions Additional recommendations may be ' required and should be given at the plan review phase. All design recommendations should also be further confirmed and/or revised at the completion of remedial grading based on the expansion characteristics of the I foundation bearing soils and as-graded site geotechnical conditions, and presented in the final as-graded compaction report I '1. Continuous strip wall foundations should be sized at least .18 inches wide and 24 inches deep. Spread pad footings should be at least 36 inches square and 18 inches deep Footing depths are measured from the lowest adjacent ground 1 surface, not including the sand/gravel layer beneath the floor slabs Exterior - continuous footings should enclose the entire building perimeter. 1 2. Continuous interior and exterior foundations should be reinforced with a minimum of four #5 reinforcing bars. Place 245 bars. 3 inches above the bottom of the footing and 245 bars 3 inches below the top of the footing 1 Reinforcement details for isolated pad footings should be provided by the project architect I structural engineer. . . 3. All interior slabs should be aminimum of 5 inches in thickness, reinforced with #3 reinforcing bars spaced 16 inches on center each way placed mid-height in I . . the slab. Slabs should be underlain 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. . . . . . . I I VINJE & MIDDLETON ENGINEERING, INC 2450 Vineyard Avenue Escondido California 92029-1229 • Phone (760) 743-1214 Fax (760) 739 0343 QEOTECHNICAL INVESTIGATIONS . GRADING SUPERVISION . PERC TESTING ENVIRONMENTAL INVESTIGATION. Li I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 17 EL CAMINO REAL, CARLSBAD, CALIFORNIA : OCTOBER 17, 2003 4. Provide "softcut" contraction/control joints consisting of sawcuts spaced 10 feet on center maximum each way. Cut as soon as the slabWill support the weight I 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 11/4 1 inches deep maximum. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. Avoid wheeled equipment 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 I enclosed Plate 9 maybe used as a general guideline. I 6. Foundation bearing and slab subgrade soils should not be allowed to dry below the as-graded moisture contents prior to pouring the concrete or additional ground preparations and moisture re-conditioning will be required as directed I in the field. 7. Foundation trenches and slab subgrade soils should be inspected and tested I for proper moisture and specified compaction levels, and approved by the project geotechnical consultant prior to the placement of concrete. I C. Exterior Concrete Slabs I Flatworks 1. All exterior slabs (walkways, and patios) should be a minimum of 4 inches in I thickness reinforced with 6x6/10x10 welded wire mesh carefully placed mid- height in the slab. I 2. Provide "tool joint" or "softcut" contraction/control joints spaced 10 feet on center (not to exceed 12 feet maximum) each way. Tool or cut as soon as the slab will support weight and can be operated without disturbing the final finish I , which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. Tool or softcuts should be a minimum of 1-inch but should not exceed I 1h-inches deep maximum. In case of softcut joints, 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. I 3. All exterior slab designs should be confirmed in the final as-graded compaction report. I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 (EOTECHNICAL INVESTIGATIONS - GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTUATION .1 I ILI I I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 18 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 4 Subgrade soils should be tested for proper moisture and specified compaction I levels, and approved by the project geotechnical consultant prior to the placement of concrete. D. Soil Design Parameters The following soil design parameters are based upon 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 = 124 pcf. * Design angle of internal friction of soil = 30 degrees * Design active soil pressure for retaining structures = 41 pcf (EFP), level backfill, cantilever, unrestrained walls. * Design active soil pressure for retaining structures = 67 pcf (EFP), 2:1 sloping backfill surface, cantilever, unrestrained walls. * Design at-rest soil pressure for retaining structures = 62 pôf (EFP), non- yielding, restrained walls. * Design passive soil pressure for retaining structures = 374 pcf (EFP), level surface at the toe. * Design coefficient of friction for concrete on soils = 0.36 * Net allowable foundation pressure (minimum 18 inches wide by 24 inches deep footings) = 2500 psf. * Allowable lateral bearing pressure (all structures except retaining walls) for certified on-site soils = 150 psfift'. i 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 minimum safety factor of 2 may be considered for sliding stability particularly where sensitive structures and improvements are planned near or on top of retaining walls. When combining passive pressure and frictional resistance, the passive component should be reduced by one-third. * The indicated net allowable foundation pressures provided herein were determined based on a minimum 18 inches wide by 24 inches deep footings I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743:1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PL RC TESTING ENVIRONMENTAL INVESTIqATION I 1 PRELIMINARY GEOTECHNICAL INVESTIGATION . PAGE 19 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 and may be increased by 20% for each additional foot of depth and 20% for each additional foot of width to a maximum of 4500 psf. The allowable I' foundation pressures provided herein also apply to dead plus live loads and may be increased by one-third for wind and seismic loading. - I * The .lateral bearing earth pressures may be increased by the amount of designated value for each additional foot of depth to a maximum of 1500 pounds per square foot. ' E. Asphalt and PCC Pavement Design. . Specific pavement designs can best be provided at the completion of rough I grading based on R-vaIue tests of the actual finish subgrade soils; however,, the following structural sections may be considered for cost estimating purposes only (not for construction) A minimum section of 3 inches asphalt an 6 inches Caltrahs Class 2 aggregate 'base may be considered for the on-site asphalt paving surfaces. In the areas. I ,.where the longitudinal grades exceed 10%, one-half inch asphalt, should, be added to the design asphalt thickness for each 2% increase in grade or portions thereof. PCC paving is recommended for longitudinal grades over 15% and will I . ' be required when longitudinal grades are 20% or more. . Actual designs will also depend on the design TI and approval of the City of I Carlsbad. Base materials should be compacted to a minimum of 95% of the I ,corresponding maximum dry density (ASTM D-1557). Subgrade soils beneath the asphalt paving surfaces should also be compacted to minimum of 95% of the corresponding maximum dry density within the upper 12 inches. Residential PCC driveways and parking supported on low expansive (expansion index less than 51) subgrade soils should be a minimum of 51/2 inches, in I ,thickness, reinforced with #3 reinforcing bars at 18 inches on center each way placed 2 inches below the top of slab. . Subgrade soils beneath the PCC driveways and parking should be compacted to a minimum of 90% of the corresponding maximum dry, density within the upper 6 inches. For grades over '15%, provide a minimum 6 inches wide by 8 inches deep shear key perpendicular to the longitudinal profile, monolithically poured at the base of the I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vtneyard Avenue, Escondido, California 92029.1229 • Phone (760) 743-1214'0 Fax (760) 739-0343 QEOTECHNICAL INVESTIGATIONS ' GRADING SUPERVISION . , I'ERC TESTING ENVIRONMENTAL INVESTIQATION. PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 20 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 PCC paving section at 15 feet on centers maximum Use a minimum 560-C- 3250 concrete per Standard Specifications for Public Works Construction (Green Book) for all PCC paving surfaces. Provide "tool joint" or "sbftcut". contraction / control joints spaced 10 feet on center (not to exceed 15 feet maximum) each way. Tool or cut as soon as the slab will support weight and can be operated 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. Tool or softcuts should be a minimum of 1-inch but should notexceed 11h-inches deep maximum. In case of softcut joints, 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. I . 3. Subgrade and basegrade soils should be tested for proper 'moisture and specified compaction levels and approved by the project geotechnical consultant prior to the placement of the base or asphalt / PCC finish surface. 1 4.. Base section and-subgrade preparations per structural section design, will be required for all surfaces subject to traffic including roadways, travelways, drive I 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 1 2 base section per the structural section design. Provide 6 inches of Class 2 base under curb and gutters and 4 inches of Class .2 base (or 6 inches of Class Ill) under sidewalks. Base layer under curb and gutters should be compacted to a minimum of 95%, while subgrade soils under curb and gutters, and base and subgrade under sidewalks should be compacted to a minimum of 90% compaction levels. Base section may not be required under curb and gutters, and sidewalks in the case of very low expansive subgrade soils (expansion index less than 21). Appropriate recommendations should be given in the final as-graded compaction report.. I I I ., I, F. General Recommendations 1. The minimum foundation design and steel reinforcement provided herein is based on , soil characteristics only and is not intended to be in lieu of reinforcement necessary for structural consideration All recommendations should be evaluated and confirmed by the project architect / structural engineer. IVINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 QEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION I'ERC TESTING - ENVIRONMENTAL INVESTIGATION I I I 'H I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 21 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 2 Adequate staking and grading control is a critical factor in properly completing the recommended remedial and site grading operations. Grading control and staking should be provided by the project grading contractor, or surveyor/civil * engineer and is beyond the geotechnical engineering services. Inadequate staking and/or lack of grading control may result in unnecessary additional I grading which will increase construction costs. I 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) 1 '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. 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. All underground utility and plumbing trenches should be mechanically comp'abted to a minimum of 90% of the maximum dry density Of the soil unless otherwise 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. Based upon the results of the tested soil sample; the amount of water soluble sulfate (SO4) in the soil was found to be 0.013 percent by, weight which is considered negligible according to California Building Code Table No. 19-A-4. Portland cement Type II may be used. , Potentially expansive clayey deposits are subject to continued swelling and shrinkage upon wetting and drying. At,the site, maintaining a uniform as- 'graded soil moisture during the post construction periods is essential in the future performance of the site structures and improvements. In no case should water be allowed to pond or accumulate adjacent to the improvements and structures, ' Site drainage'over the finished pad surface 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 of the buildings should be provided with I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739.0343 EOTECHNICAL INVESTIGATIONS GRADING SUPERVISION I'ERC TESTING ENVIRONMENTAL INVESTIGATION PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 22 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 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. Final plans should reflect preliminary recommendations given in this report. Final foundations and grading plans may be reviewed by the project geotechnical consultant for conformance with the requirements of the geotechnical investigation report outlined herein. More specific recommendations may also be necessary and should be given when final grading and arch itectural/structurai drawings are available. 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. The amount of shrinkage and related cracks that occur in the concrete slab-on- grades, flatworks and driveways depends on many factors, the most important of which is the amount of water in a 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 thatcan be handled and consolidated satisfactorily. * Use the largest maximum size of aggregate that is practical, (for example, concrete made with 3/8-inch maximum size aggregate usually requires about 40 lbs 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, reinforcementprovided for conventional slab-on-grade construction considers that good quality concrete materials,- proportioning, craftsmanship, and control tests where appropriate and applicable, are provided. I I I VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029-1229 • Phone (760) 743-1214 • Fax (760) 739-0343 cEOTECI-INsCAL INVESTIQATIONS . QRADINQ SUPERVISION - PERC TESTING ENVIRONMENTAL INVESTIQATION F I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 23 EL CAMINO REAL,. CARLSBAD, CALIFORNIA OCTOBER 17, 2003 12 A preconstruction meeting between representatives of this office, the property owner or planner, the grading contractor / builder, and the city inspector is I recommended in order to discuss grading/construction details associated with site development. VIII LIMITATIONS The conclusions and recommendations provided herein have been based on available data obtained from the review of pertinent reports and plans, subsurface exploratory I 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 I may vary in characteristics between excavations. Of, necessity we must assume a certain degree of continuity between exploratory I 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 I be made and additional recommendations issued if required. The recommendations made in this report are applicable to the site at the time this report I was prepared. It is the responsibility of the owner/developer to ensure that these recommendations are carried out in the field. I 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 I 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 I ground movement. Hairline stucco cracks will often develop at window/doOr corners, and floor surface cracks up to 1/87inch wide in 20 feet may develop as a result of normal concrete shrinkage (according to the American Concrete Institute). i I VINJE &MIDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029.1229 • Phone (760) 743-1214 • Fax (760) 739-0343 çEOTECHNICAL INVESTIGATIONS GRADING SUPERVISION PERC TESTING ENVIRONMENTAL INVESTIGATION I I PRELIMINARY GEOTECHNICAL INVESTIGATION PAGE 24 EL CAMINO REAL, CARLSBAD, CALIFORNIA OCTOBER 17, 2003 This report should be considered valid for a period of one year and is subject to review by I 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. I 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. I Once again, should any questions arise concerning this report, please do not hesitate to contact this office. Reference to our Job #03-390-P will help to expedite our response to your inquiries. We appreciate this opportunity to be of service to yOu. I VINJE & MIDDLETON ENGINEERING, INC. CE I Dennis Middleton , \ ENGINEE.RhG CEG#980 . . • •\; \ 5 S1ehdi S. Shariat No. 46174 LWU R #46174 CA "I I CiVIL I Steven J. Melzer ." Pao. egiss I RG#6953 1 Distribution: Addressee (2) opc I Vista Engineering, Inc., Attn: Mr. Ki 3, fax) I I VINJE & MLDDLETON ENGINEERING, INC. 2450 Vineyard Avenue, Escondido, California 92029.1229 • Phone (760) 743.1214 • Fax (760) 739L0343 QEOTECHNICAL INVESTIGATIONS C,RM)lNç SUPERVISION I'CRC TESTING ENVIRONMENTAL INVESTIGATION ..o,. / \j PLATE S74 WAY C~ VIS7, 7Y I / 0 j Z WSTAv 0 / REGWNA L INDEX MAP / JOB #0-490-p 0 71 41 01 71 1 ç ,1 0 N D50 Ke9y N cW Ct sI-TE L.- CT LOX TrCF FLCT E Sp. UEENCT J QE At CIGO - 7 / 'RY CT - Es %5CT lox /--->- ~GNOL lAAVL - \ - -- SSc -. - \ C 49 L - $€ Al ELCAMIN0PFE INE LyE Ct Ct - N I VIEW DR 19, L \ A -- / - N - -. L - c$_ qD Scale I - 25,000 T. V. 2080 ft 2002 DeL Tepe USA S Data copyright of content owner. - wwwdelo,,nne.ccrn I I EXPLANATION - Test Trench Approximate Limits of Existing Pad Fill Geologic Cross—Section I *w41NW*0 II I J,276.1 F'I LI IPEABY: F - RING, INC 3 \'1 IL GE DRIVE C 84-6O6 TL ( 6 ) 1-2271/ II I 'JN12 03(G) L 8-25-03> 276.7 IJ7 ) I V ///// 'L TERRACE iEpllT GROUND 'I \\\ \ \\ \\ DENSE TREES / 1 x 257.2 ( \ \\\ LNY SI T//I N AND / \ \ .\ RADkJG STUD7i / \ \\\\\ \ 11 / 170 \A.P.N. 167-080-S6 / / LOT 9, MAP 538 i v 249.0 .> \ \ \ L cAF1iNc FkEAL, CAFLBAD ( \ \ \ \ \ \ \ \ JOB #03-390—P \ C) X 24 0 \ \ \ \ 'I 76. X \\\\\\\\ \w\\ \ X 2494 1 SCALE 1 =20 - I I \ \ I J _ _ _ ••? \\\\ .) III I I I I I I I ----------------------- /\ \ I I ' ,i / ) I \\\\EE/REE /1 /// J :•y: x I - I L/L A i 1050 / F9LL RQW MA R00PEI< 86±01 gwl D 8BOser .24 276.5 xft w— baJ 276.2 58 x 48' EDGE UPPER LEVE FARCEL B to 14,887 S.F. CROSS 276. I BSMT P1 267± / MAX. RC 306± EDGE BASEMENT GARAGE— 280.8 0 — ASPH 2' !L I7T/ 4f*L\/J I 17'i'T 2775 I I I I I I 1 300 280 I I 260 I I 240 I I 220 I I I I I GEOLOGIC CROSS-SECTION JOB #03-390-P A A° -- I 300 PROPOSED 3-STORY DWELLING 1 TERRACE PROPOSED GRADE t EXISTING GRADE 280 PROPOSED II 1ITTT U 3-STORY DWELLING I I I260 /R1C/k . 240 220 SCALE: 1" = 20 PLATE 3 PRIMARY DIVISIONS GROUP SECONDARY DIVISIONS SYMBOL GRAVELS CLEAN GW' 1 Well graded gravels, gravel-sand mixtures, little or no fines. GRAVELS GP Poorly graded gravels or gravel-sand mixtures, little or no fines. MORE THAN HALF (LESS THAN OF COARSE 5% FINES) co 2 0 FRACTION IS GRAVEL GM Silty gravels, gravel-sand-silt mixtures, non-plastic fines. O LU LL Z UJ OzN LARGER THAN WITH FINES GC Clayey gravels, gravel-sand-clay mixtures, plastic fines. . < NO. 4 SIEVE < fr -1 < 1— - SANDS CLEAN SW 1 Well graded sands, gravelly sands, little or no fines. SANDS SP Poorly graded sands or gravelly sands, little or no fines. w z LU FJ5 C/) <0 MORE THAN HALF (LESS THAN IEr OF COARSE 5% FINES) SM Silty sands, sand-silt mixtures, non-plastic fines. < l—< O jj FRACTION IS SANDS SMALLER THAN WITH 0 NO. 4 SIEVE NO. FINES Clayey sands, sand-clay mixtures, plastic fines. -LU ML Inorganic silts and very fine sands, rock flour, silty or clayey fine N o uJ C/) SILTS AND CLAYS sands or clayey silts with slight plasticity. O LIQUID LIMIT IS CL Inorganic clays of low to medium plasticity, gravelly clays, sandy Cl) iii clays, silty clays, lean clays. LESS THAN 50% Z . . OL Organic silts and organic silty clays of low plasticity. < i - MH Inorganic silts, micaceous or diatomaceous fine sandy or silty ir 0 w < Fr d SILTS AND CLAYS soils, elastic silts. CH ..zOz Inorganic clays of high plasticity, fat clays. LU LU Z LIQUID LIMIT IS GREATER THAN 50% OH Organic clays of medium to high plasticity, organic silts. I— HIGHLY ORGANIC SOILS PT Peat and other highly organic soils. GRAINSIZES U.S. STANDARD SERIES SIEVE CLEAR SQUARE SIEVE OPENINGS 200 40 10 4 3/4" 3" 12" SAND GRAVEL SILTS AND CLAYS I COBBLES BOULDERS FINE MEDIUM I COARSE FINE COARSE RELATIVE DENSITY 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 CONSISTENCY CLAYS AND SILTS PLASTIC VERY STRENGTH BLOWS/FOOT SOFT 0-'/4 0-2 SOFT 1,4 1/2 2-4 FIRM '/2-1 4-8 STIFF 12 8-16 VERY STIFF 2-4 16-32 HARD OVER 4- OVER 32 Blow count, 140 pound hammer falling 30 inches on 2 inch O.D. split spoon sampler (ASTM D-1 586) .Unconfined compressive strength per SOILTEST pocKet penetrometer CL-700 Sand Cone Test Bulk Sample 246 = Standard Penetration Test (SPT) (ASTM D-1 586) with blow counts per 6. inches 0 Chunk Sample 0 Driven Rings I 246 = California Sampler with blow counts per inches VINJE & MIDDLETON ENGINEERING, INC. 2450 Vineyard Ave., #102 Escondido, CA 92029-1229 KEY TO EXPLORATORY BORING LOGS Unified Soil Classification System (ASTM D-2487) PROJECT NO. I flA. KEY. U Date: 9.23-03 Logged by: SJM 1-1 USCS FIELD FIELD DRY RELATIVE DEPTH SAMPLE SYMBOL MOISTURE (%) DENSITY (pcf) COMPACTION (%) DESCRIPTION -0 - FILL: Silty fine to medium sand. Pale brown color. Dry. Loose. . ST-1 SM. - - . 9.3 111.6 89.0 TOPSOIL: _._.. - - D 1__\ . Silty fine to medium sand. Trace of clay. Dark brown color. Moist. Loose to medium dense. ST-2 SM/SC 13.2 109.5 87.3 -- -n Sandy clay to clayey sand. Tan to blue-grey color. Rust colored staining. Moist to very moist. Firm to stiff. A few scattered cobbles. . ST-2 CLISC 10.8 109.1 88.4 - 10 FORMATIONAL ROCK: . -, - Clayey to silty sandstone. Fine to coarse grained. Tan - - color. Moist. Weathered friable. Weakly cemented at SC/GC -15- upper contact. Becomes somewhat blocky and locally - - cemented at 6'. Locally cobbles and gravels. Poorly - - . sorted. Clay content decreases at depth. ST-3 - .- . End Test Trench at 8'. (No caving. No groundwater.) -20- . ,. • Date: 9-23-03 . Logged by: .SJM I . 1-2 USCS FIELD FIELD DRY RELATIVE DEPTH (ft) SAMPLE SYMBOL MOISTURE (%) DENSITY (pcf) COMPACTION (%) DESCRIPTION -TOPSOIL: I - - 1 - Silty fine to medium sand. Pale brown color. Porous to - - . highly porous. Dry. Loose. Scattered cobbles and gravel. SM - 2 -j Roots up to 6" in diameter from nearby eucalyptus trees. 1.6 104.0 - I ST-1 -3- I - - Clayey sand. Medium to coarse grained. Red-brown I ) Moist. Loose to medium dense. Porous. Scattered SC - -color. - - cobbles. Clay content decrease at depth. ST-2 -5- FORMATIONAL ROCK: . I -- - 6 - Cobble conglomerate. ± 25% cobbles 6" minus. Silty to - - clayey sand matrix. Fine to medium grained. Red-brown CC 8.8 105.2 83.9 - 7 - DU color. Weakly cemented. Moist. Difficult to excavate. ST-4 7.2 114.0 90.9 'End Test Trench at 10'. (No caving. No groundwater.) - --. I VINJE & MIDDLETON ENGINEERING, INC TEST TRENCH LOGS 2450 Vineyard Avenue, Suite 102 Escondido, California 92O29-1229 EL CAMINO REAL, CARLSBAD PROJECT NO. 03-390-P PLATE 4 I Office 760-743-1214 Fax 760-739-0343 V Sand Cone Test U Bulk Sample U Chunk Sample 0 Driven Rings Date: 9-23-03 Logged by: SJM DEPTH (ft) SAMPLE T3 USCS SYMBOL FIELD MOISTURE (%) FIELD, DRY DENSITY (pcf) RELATIVE COMPACTION (%) DESCRIPTION - - FILL: ' —1 - Silty fine to medium sand. Scattered cobbles. Pale brown 'SM - - Color. Dry. Medium dense. No evidence of benching. -2- ST-1' TOPSOIL: 3 Sandy clay to clayey sand. Red-brown color. Moist. CL/SC - 4 - \ Blocky: ST-2 FORMATIONAL ROCK: 5 - - - \ Silty sandstone. Medium to coarse grained. Trace ofclay. SP/SC - 6 - Off-white color. Blocky. Cemented. Massive. Poorly - - sorted. , . ST-3 -7- - - End Test Trench at 31/2'. (No caving. No groundwater.) - 8 - Date: 9-23-03 . . Logged by: SJM DEPTH (ft) SAMPLE' . . USGS TA SYMBOL' FIELD MOISTURE (%) FIELD DRY DENSITY (pcf) RELATIVE COMPACTION (%) . , , DESCRIPTION - - - 1 - FILL: Silty sand / cobble mix. Red-brown color. Up to 50% GP - -. cobbles by volume. Dry. Medium dense. ST-5 TOPSOIL: - 3 - Silty fine sand. Pale brown color. Porous. Dry. Loose. SM, 4 -Some rootlets. Locally gravelly. ST-1 I - - 5 - Sandy clay to clayey sand. Red-brown color. Moist. CL/SC Blocky. Stiff. . - 6 - . ST-2 . 10.2. 126.6 100+ - 7 - FORMATIONAL ROCK: - 8— Siltstone. Pale grey color. Locally sandy. Blocky.________ Indurated. SP . - 9 - Grades to sandstone at 7. Fine to coarse grained. Off- white color. Blocky. Cemented. Poorly sorted. Some rust 10 - . _10 - colored staining. No apparent structures. ST-3 End Test Trench at 8. '(No caving. No groundwater.) - 11 - VINJE & MIDDLETON ENGINEERING, INC TEST TRENCH LOGS 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 EL CAMINO REAL, CARLSBAD PROJECT NO. 03-390-P PLATE 5 Office 60-743-1214 Fax 760-739-0343 U V Sand Cone Test • Bulk 'Sample U Chunk Sample 0 Driven Rings I I I Li I I I [1 I Date: 9-23-03 Logged by: SJM T-5 FIELD . USCS FIELD DRY RELATIVE I DEPTH SAMPLE SYMBOL MOISTURE DENSITY COMPACTION (ft) DESCRIPTION (%) (pcf) (%) FILL 9.4 126.7 100+ 1 - - Silty fine sand/cobble mix. Red-brown color. Dry. Blocky. GP ST-5 2 I-- FORMATIONAL ROCK: - 3 - Silty sandstone: Medium to coarse grained. Locally trace S P/SC - - of clay. Off-white color. Rust colored staining. Poorly I - -sorted. Blocky. Cemented. ST-3 -5- 16 - - End Test Trench at 2'. (No caving. No groundwater.) Date: 9-23-03 Logged by: SJM T-6 FIELD USCS FIELD DRY RELATIVE DEPTH (if) SAMPLE DESCRIPTION SYMBOL MOISTURE (%) DENSITY (pcf) COMPACTION (%) - - FILL I TOPSOIL: 1Silty fine to medium sand. Up to 50% cobbles and GP I- - - pebbles by volume. Dry. Somewhat loose. ST-5 -2- -FORMATIONAL ROCK: I - 3— Silty sandstone. Fine to medium grained. Locally trace of - - clay. Off-white. Rust colored Staining. Weathered friable SP/SC - 4 - near surface. Becomes somewhat blocky and moderately I - -cemented at 2'. No apparent structure. -5- ST-3 I i 6End Test Trench at 3'. (No caving. No groundwater.) -7- 118 _10- I VINJE & MIDDLETON ENGINEERING, INC TEST TRENCH LOGS I 2450 Vineyard Avenue, Suite 102 Escondido, California 92029-1229 EL CAMINO REAL, CARLSBAD I Office 760-743-1214 Fax 760-739-0343 PROJECT NO. 03-390-P PLATE 6 V Sand Cone Test U Bulk Sample L1 Chunk Sample 0 Driven Rings I A (-- _ : / 011 CP CD I- 1% - p SITE _s XT, - T L1 Centro, - - I Son Otego I\ 0 - - - - - - 0 30 20 10 0 30 MILES no I FAULT - EPICENTER MAP I SAN blEoo COUNTY REGION I INDICATED EARTHQUAKE EVENTS THROUGH 75 YEAR PERIOD (1900-1974) Map daa is compiled from various sources including California Division of Mines and Geology, California Institude of. Technology and the National Oceanic and Atmospheric I Administration. Map is reproduced from California Division of Mines and Geology, "Earthquake Epicenter Map of California; Map Sheet 39.". farthquake Magnitude ...............4.0T04.9 5.0 TO 59 PROJECT: Job #03-390-P 101 . ...........6.OTOG.9 EL CAMINO REAL, CARLSBAD I 0 --- Fault. PLATE 7 Perforated drain, pipe I Filter Material. Crushed rock (wrapped in filter fabric) or Class 2 Permeable Material (see specifications below) Competent, approved soils or bedrock CONSTRUCTION SPECIFICATIONS: Provide granular, non-expansive backfill soil in 1:1 gradient wedge behind wall. Compact backfill to minimum 90% of laboratory standard. Provide back drainage for wall to prevent buildup of hydrostatic pressures. Use drainage openings along base of wall or back drain system as outlined below. . Backdrain should consist of 4" diameter PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable outlet at minimum 1%. Provide 3/4" - 11/2" 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. Seal back of wall with waterproofing in accordance with architect's specifications. Provide positive drainage to disallow ponding of water above wall. Lined drainage ditch to minimum 2% flow away from wall is recommended. . * Use 11/2 cubic foot per foot with granular backfill soil and 4 cubic foot per foot if expansive backfill soil is used. VINJE & MIDDLETON ENGINEERING, INC. PLATE 8 (a) (b) TION JOINTS ACTION JOINTS (c) ENTRANT NER CRACK RE-ENTRANT C( REIN FO RCEM EN NO. 4 BARS PL BELOW TOP OF ISOLATION JOINTS AND RE-ENTRANT CORNER REINFORCEMENT Typical - no scale NOTES: 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 Ad). In order to control cracking at the re-entrant corners (±2700 corners), provide reinforcement as shown in (c). 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 9