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2002-7111 G FA TA I T Consulting, Inc. 717 Pier View Way Oceanside, CA 92054 Phone 760 433 -1166 Fax 760 433 -1017 TURNER RESIDENCE DATE: SEPTEMBER 10, 2001 ADDRESS: 1024 HYMETTIUS AVENUE, ENCINITAS, CA.92024 APN #: 254 - 331 -19 DRAINAGE ANALYSIS THE EXISITING DWELLING IS TO BE DEMOLISHED AND MINOR GRADING WILL BE DONE FOR THE NEW DRIVEWAY, BEFORE THE CONSTRUCTION OF A NEW DWELLING. THERE IS NO INGRESS OF STORMWATER FROM OFFSITE SOURCES. THE DRAINAGE PATTERN FOR THE PROPOSED GRADING, HAS NOT ALTERED FROM THE EXISTING. THE FLOW FROM THE ROOF WILL BE COLLECTED, AND TEMPORARLIY STORED IN AN UNDERGROUND TANK WHICH WILL BE USED FOR GARDEN IRRIGATION. THEREFORE, THE FLOW FROM THE PROPOSED DEVELOPED SITE,WILL NOT EXCEED THE FLOW FROM THE EXISTING DEVELPOED SITUATION. W No. 3224 ¢ Exp< 1 -�-- -� I Y lE - F��\� OF cr y DEH'- DEM.. ME PER( Data 3/13/ kssessor's Parcel !: 254 - 330 -19 -" Site Location 1024 Hymettus Leucadia - -" David Turner :)wner's Name mailing Address Same Tsst Test Ave(age Rate Holt Depth Time/Inch (Time/Inch) 1 33 ft 7272 gal /day 06 AIN Pti'C) I t+: Y 00 c cs. =oT T f :',< PER" T . HOW VEER, A SiTf= PEC,-tEC MAY 5E'` ED AT f�,N t IIV,_: SITF Vertical seepage pfts: Provldo solls log, vr test resuhs, and calculations on se rate 8 -%" x f f sheets of TYPE OF SOIL: (clay, silt, sand, decomposed granite, etc.) I observed the pit drilled t043 feet; silty sand a 72 hr. wait, then a 10 foot backfill S urf a ce- -ft. below surface _ft. below surface xev (Y AM F f t3. ,+i19" U W. RUi)_t}I 06 —ft. below surfac I. R I ft. below surfac J- , 1 L - A - 5 MUM. Depth to refusal Depth to groundwater unknown C ounty D iego �. qf Source of potable water- San Die ui to Water Di stri ct In My Professional Opinion The Historic High Water Table Will Not Rise To Within 10' Of Pit Bottom Proposed structure 5 Bed. Res. + 1 Bed. Guest House �Ik/ C 2 Pits - Primary RECOMMENDATIONS 2 Pits - Reserve I have reviewsd tHs percolation data " design of tha eubnrfaca sewage dlsposal system for this Parcel and find the dau and design to Sept;;; tank ire 1500 nzI pit length ft. an in c ompliance with sta " local repuUbone and good Leach line length ft. Pit width 4 ft. E 26404 Trench depth ft. Pit depth* 33 ft Re 'stered CE, PE, Geologist, REHS 2187 ewcastle Avenue Ste 103 Rock under pipe in. Cap depth' 5 ft. Cardiff CA 92007 ( 760) 436 -8500 3/13/01 h s yJ ��v,'.� t r � /:. �j f� 'BELOW GRADE Address Phone Date // ✓ / n l D re FOR DEPARTMENTAL USE ONLY APPROVED: YES DATE y! Vle FINAL MAP REQUIRED: YES. —_ N0 • iatist: g. Plan Review Date Grading Review Date Water Analysis Results Date DE+:LU -7st (pros) JOB F Ule -A(aC. tt KN 24 530 i SOWARDS AND BROWN GINEERING SHEET NO. OF 2187 Newcastle Ave., Suite 103 CALCULATED BY DATE CARDIFF BY THE SEA, CALIFORNIA 92007 CHECKED BY DATE SCALE ._ .......... ..... .... , ..... C.p ............. --........? ........................ ...............'.............i. —'—"^-- ................._....... ._....,............._.......... ...... .. .... .. _... ............. .... _....._ ...... ...... .... ..... ........ . ...... _ ...... ...... ...... ..... t i ' . --..._.___..._ ........ ................................... .._.. ..... ... _ ..... ..... ..... .. .... ..... ... _ ...... ...... ...... ...... ._.. ..............._... _ ._... _.... s ...... i ... _.. .. .. .... ... .... __._ .._. ....._ 0 ... � ... ...... ...... _ ...... .. ...... ......_ .... .._. .. _ .. ..__.. ......__.:-.... ...... ........; ... ........... ...... 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OF 2187 Newcastle Ave., Suite 103 CALCULATED BY DATE CARDIFF BY THE SEA, CALIFORNIA 92007 CHECKED BY DATE SCALE . . . . ..... . . ......... . ........... ......... . .. ... . ...... ..... .... .... ... .. ...... ... .. .......... ....... ....... - . ......... ....... ..... . ........... . . ......... - C- Q -4- ....... ..... .......... . ......... ... : .w+..v-x�.+. • f.r.,' x.r x u x..+r. _n. ..574.•1x' 1N I I i -, `\ , / ✓ '•, 1 W AY O ) � w 1 I"N 0 i I O I f O I � w 4 � I / �F y i • 1 1 , ` 1 O "UI ap prova l will/6e Y016'unles , the Structure ' O L each Lines or Se Pit(s) are located "actt�4Y2'31 as shown on this plan. ANY proposed change shall - - apPrDvve� h�. r Gapartment of Environmental lth prior tv t,19nirg construction, and m ay j I 9--uir�r ad�f;c 06 -1 sail testing. There shall be a 5: setback required from all utility trenches to the I Turner 25.00' the lines. The setback shall be measured from the tots Hymettus I 1 of the utility tranch to the closest edge of the the line." vitas, Ca., 92024 254- 330 -19 y L- ; US � �'� NP jP` gallons used in 24 hours MAR 2 3 Hill I NA bounty of San Diep q �R c� v � 7272 gal /day I � i1 lronfnevt �c;e sT � z � poll � � LE U— �EUCADIA JP ;�`j indicates seepage pit RfLtDSJOE — OF elROpA 5 MAOEM ® indicates reserve pit fiX MHP E 0 p Distribution box S j �S 5 - t- f -tt -- tight line ` r I t N i j -� A �p� 1500 gal septic tank V 41 CZty Of NGINEERING SER VICES DEPARTMENT / Ca ital Improvement Pro Encinitas P p District Support Services Field Operations Sand Replenishment/Stormwater Compliance Subdivision Engineering Traffic Engineering June 14, 2006 Attn: Union Bank of California 1435 Camino Del Mar Del Mar, California 92014 RE: Turner, David and Vicki 1024 Hymettus Avenue APN 254- 330 -19 Grading Permit 7111 -G Final release of security Permit 7111 -G authorized earthwork, private drainage improvements, and erosion control, all as necessary to build/prepare the project as shown on approved plans. The Field Inspector has approved the project. Therefore, a full release in the security deposit is merited. Certificate of Deposit Account 0229056726, in the amount of $44,000.00, may be released in entirety. (The account was approved for a reduction to $11,000 on December 10, 2002). The original document is enclosed. Should you have any questions or concerns, please contact Debra Geishart at (760) 633- 2779 or in writing, attention this Department. Sincerely, Debra Geisha J Le bach Engineering Technician finance Manager Subdivision Engineering Financial Services cc Jay Lembach, Finance Manager David and Vicki Turner Debra Geishart File Enc. TEL 760- 633 -2600 / FAX 760 - 633 -2627 505 S. Vulcan Avenue, Encinitas, California 92024 -3633 TDD 760 - 633 -2700 7*,� recycled paper v CHRISTIAN WHEELER- EN GIN EER-1 NG REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYMETTUS AVENUE ENCINITAS, CALIFORNIA 0 Z 2001 v �� i FNGINEERINGSERVICEF CITYQF ENCINITAS PREPARED FOR: DAVID AND VICKI TURNER 1024 HYMETTUS AVENUE ENCINITAS, CALIFORNIA 92024 PREPARED BY: CHRISTIAN WHEELER ENGINEERING 4925 MERCURY STREET SAN DIEGO, CALIFORNIA 92111 4925 Mercury Street ♦ San Diego, CA 92111 ♦ 858- 496 -9760 ♦ FAX 858- 496 -9758 W CHRISTIAN WHEELER ENGINEERING October 26, 2000 David and Vicki Turner CWE 200.563.1 1024 Hymettus Avenue Encinitas, California 92024 SUBJECT: REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED SINGLE - FAMILY RESIDENCE, 1024 HYMETTUS, ENCINITAS, CALIFORNIA. Dear Mr. and Mss. Turner: In accordance with your request and our Proposal dated September 13, 2000, we have completed a preliminary geotechnical investigation for the subject property. We are presenting herewith our findings and recommendations. In general, no geotechnical conditio were encountered that would preclude the construction of the proposed residence and associated improvements, provided the recommendations contained in this report are followed. The site is underlain by loose to medium dense, man - placed fill material in the east - central portion and dense terrace deposits in the eastern and western portions. The existing fill material is not conside suitable in its present condition to support settlement - sensitive structures and improvements and will need to be removed and replaced as compacted structural fill. In addition, it is anticipated that a cut /fill transition will run through the new building pad. In order to provide a uniform mat of soil to support the proposed structure, it will be necessary to undercut the cut portion of the building pad and replace the excavated soil as compacted structural fill. If you have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. Respectfully submitted, { l F CHRISTIAN WHEELER ENGINEERING Q' 4 �e� 6z= fV ,CC ;_i��1ST o� e � 5 H. �y9�F�� ,x�. �o 00 Charles H. Christian R.G.E. #00215 �� -I %� rtts R. Burdett C.E.G. 1090 yr �.G�j` u r -�- co v No. GF ^0215 - �'° 0 CHC:CRB:scc u, J r cc: (6) Submitted 1 - Fxp r C 4925 Mercury Street + San Diego, CA 92111 + 858- 496 -9760 + FAX 858- 496 -9758 TABLE OF CONTENTS PAGE Introduction and Project Description ................................................................................ ..............................1 ProjectScope .......................................................................................................................... ..............................1 Findings.................................................................................................................................. ............................... 2 SiteDescription .............................................................................................................. ............................... 2 General Geology and Subsurface Conditions ............................................................ ..............................3 Geologic Setting and Soil Description ................................................................... ............................... 3 ArtificialFill ............................................................................................................ ............................... 3 Topsoil..................................................................................................................... ............................... 3 TerraceDeposits ..................................................................................................... ..............................3 Groundwater.............................................................................................................. ............................... 4 TectonicSetting .......................................................................................................... ..............................4 GeologicHazards .......................................................................................................... ............................... 4 General........................................................................................................................ ............................... 4 GroundShaking ......................................................................................................... ..............................4 SeismicDesign Parameters ....................................................................................... ..............................5 Landslide Potential and Slope Stability .................................................................. ............................... 5 Liq ............................... 6 Flooding...................................................................................................................... ............................... 6 Tsunamis.................................................................................................................... ............................... 6 Seiches......................................................................................................................... ............................... 6 C ............................... 6 R ............................... 6 Gradingand Earthwork ................................................................................................ ............................... 6 General........................................................................................................................ ............................... 6 Observationof Grading ........................................................................................... ............................... 7 Clearingand Grubbing ............................................................................................. ............................... 7 SitePreparation ......................................................................................................... ............................... 7 Cut /Fill Transition .................................................................................................... ............................... 7 Processingof Fill Areas ............................................................................................ ............................... 8 Compactionand Method of Filling ........................................................................ ............................... 8 FillSlope Construction ............................................................................................ ............................... 8 ImportedFill Material .............................................................................................. ............................... 8 SurfaceDrainage ....................................................................................................... ............................... 9 GradingPlan Review ................................................................................................ ............................... 9 Foundations.................................................................................................................... ............................... 9 General....................................................................................................................... ............................... 9 BearingCapacity ........................................................................................................ ............................... 9 FootingReinforcement ............................................................................................ ............................... 9 LateralLoad Resistance ............................................................................................ ............................... 9 SettlementCharacteristics ........................................................................................ .............................10 ExpansiveCharacteristics ........................................................................................ .............................10 FoundationPlan Review .......................................................................................... .............................10 Foundation Excavation Observation ..................................................................... .............................10 On -Grade Slabs ............................................................................................................. .............................10 InteriorFloor Slab .................................................................................................... .............................10 Moisture Protection for Interior Slabs .................................................................. .............................10 ExteriorConcrete Flatwork ..................................................................................... .............................11 EarthRetaining Walls ................................................................................................... .............................11 C%TVE 200.563 Single- Family Residence 1024 Hymettus Avenue Encinitas, California F oun d a ti on s ............................................................................................................... ............................. PassivePressure ......................................................................................................... .............................11 EquivalentFluid Pressures ...................................................................................... .............................11 Waterproofing and Subdrain Observation ............................................................ .............................11 B a ckfill ........................................................................................................................ .............................11 Limitations ............................................................................................................................. ............................. Review, Observation, and Testing .............................................................................. .............................12 Uniformityof Conditions ............................................................................................. .............................12 Changein Scope ............................................................................................................ .............................12 TimeLimitations ............................................................................................................ .............................12 ProfessionalStandard .................................................................................................... .............................13 Client's Responsibility ................................................................................................... .............................13 FieldExplorations ................................................................................................................. .............................13 LaboratoryTesting ................................................................................................................ .............................14 ATTACHMENTS TABLES Table I Maximum Bedrock Accelerations, Page 5 Table II Seismic Design Parameters, Page 5 FIGURES Figure 1 Site Vicinity Map, Follows Page 1 PLATES Plate 1 Site Plan Plates 2 -5 Test Pit Logs Plate 6 Suggested Subdrain Detail Plate 7 Laboratory Test Results APPENDICES Appendix A References Appendix B Recommended Grading Specifications: General Provisions CINE 200.563 Single - Family Residence 1024 Hymettus Avenue Encinitas, California W CHRISTIAN WHEELER ENGINEERING PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYMETTUS AVENUE ENCINITAS. CALIFORNIA INTRODUCTION AND PROJECT DESCRIPTION This report presents the results of our preliminary geotechnical investigation for a proposed single - family residence to be constructed at 1024 Hymettus A venue, in the City of Encinitas, California. The location of the project site is shown on Figure Number 1. In order to augment our understanding of the proposed project, the client has provided our firm with an existing site plan for the project. This site plan has been modified by our firm to show the approximate locations of our subsurface explorations and to provide approximate geologic mapping of the site. The project site is an existing residential property that was developed sometime in the 1920's. The lot currently supports a single - family residence and detached garage with associated improvements. We understand that the existing improvements will be razed and that a new residence and driveway improvements are planned. The new residence will be a two -story structure and is expected to consist of wood -frame construction that will be supported by conventional shallow spread footings. The new residence is also expected to incorporate a concrete slab -on -grade floor system. In addition, we understand that the lot will be regraded in order to add more area to the western end of the building pad to accommodate the proposed improvements. As part of creating this additional area, a retaining wall will be constructed along a portion of the northern property line that will have a height of up to five feet. The grading is expected to consist of cuts and fills of less than ten feet from the existing grades. PROJECT SCOPE Our investigation consisted of: surface reconnaissance, subsurface explorations, obtaining representative disturbed and undisturbed samples, laboratory testing, analysis of the field and laboratory data, research of available geologic literature and geotechnical documents pertaining to the site, and preparation of this report. More specifically, the intent of this investigation was to: a) Explore the subsurface conditions to the depths influenced by the proposed construction. 4925 Mercury Street + San Diego, CA 92111 + 858- 496 -9760 + FAX 858- 496 -9758 E M om L - � •+� �i„�`u�.>=r�' "'' +c gs x t � r s � Q T,� °�' �..e. G.."a �` �ry a y '° ;�"' y � w.le, '� sadk � ��' h� a. JI s'�'� � .. Ni l ,r . *, ,, 'm f i" 'i'""'.� �e r � �` a 't • �„FJ fP Y � � � � �) �� `� � .�y , n4 a #W �. 4 ') £ $ � ��`�3 '3' �� d E�'' j ' a s^'P��g', � � r> ,«v � # -,+�p . t,,,,_ 4 "��,^'' � � au ix - ' . r '.eT t- �; .z ,t iw � ��'� �r"� a �.,�' 1 v � s.:� , iu � e»s '• a ?, u- „�. * ." .. c l "�.>"b f""a`W' asiG',k :� ..�a�..`' "' 1.+ i�� .� ,^ ..a,,, Ln.e. T ',a'� "Y .. ra .�a. ta,u ti � t u-� °' 3 A 3 rx � Y x tr s ,�. � _ 3• "'; �� `�. „, r Wa 'e a _ �m[+ y "c„# yd� g c � � t u � � -� ad i a / /'� a l AP- ° a 4 `• � � c � re 2. 're +a , � s «s�. +�� .�,�,Y. �. d :r P SA IG P L i re t � ,} f s �� z 4 A A, 4 J WR i "=# �� . „- �§ � � m i 3� S .- s wFd '0 # . �. ' � �� ' r• 1 .� � �� i ^i .� � Y<' i a2 ohs s �e �,...i. �. a4.. ,n..,. ��•. ,:x -* ...��. _ sA _r...s _ ;42'+ CWE 200.563.1 October 26, 2000 Page No. 2 b) Evaluate, by laboratory tests, the pertinent engineering properties of the various strata which may influence the proposed construction, including bearing capacities, expansive characteristics, and settlement potential. c) Describe the general geology at the site including possible geologic hazards that could have an effect on the site development, and provide the seismic design parameters as required by the most recent edition of the Uniform Building Code. d) Address potential construction difficulties that may be encountered due to soil conditions, groundwater or geologic hazards, and provide recommendations concerning these problems. e) Develop soil engineering criteria for site preparation and precise grading, if necessary. f) Provide recommendations for an appropriate foundation system for the type of structure anticipated and develop soil engineering design criteria for the recommended foundation design. g) Provide design parameters for "unrestrained" earth retaining walls. h) Present our professional opinions in this report, which includes in addition to our conclusions and recommendations, a plot plan, exploration logs and a summary of the laboratory test results. It was not within the scope of our services to perform laboratory tests to evaluate the chemical characteristics of the on -site soils in regard to their potentially corrosive impact to on -grade concrete and below grade improvements. If desired, we can obtain samples of representative soils and submit them to a chemical laboratory for analysis. Further, it should be understood Christian `/heeler Engineering does not practice corrosion engineering. If such an analysis is necessary, we recommend that the client retain an engineering firm that specializes in this field to consult with them on this matter. FINDINGS SITE DESCRIPTION The subject site consists of a rectangular- shaped lot located westerly and adjacent to Hymettus Avenue, in the City of Encinitas, California. The site is identified by the address of 1024 Hymettus Avenue. Access to the site is afforded by Hymettus Avenue, which borders the site to the east. The site is bordered to the north, south, and west be developed residential properties. The lot was apparently developed sometime in the 1920's CWE 200.563.1 October 26, 2000 Page No. 3 and existing improvements include a single- story, single- family residence and associated improvements in the central portion of the site. A small, single -story garage exists just north of the house. The house and garage are of wood -frame construction and are expected to be supported by conventional footings. Vegetation on the site consists primarily of lawn and typical landscaping flora with several small and large trees around the perimeter of the site and two relatively large trees at the west end of the building pad. Topographically, the building pad is relatively level and is the highest portion of the site. The site falls off towards Hymettus Avenue to the east with a gentle slope in the front and towards the west with a gentle to moderate slope behind the building pad. Based on a topographic survey prepared by John Douglas Baker, elevations at the site range from approximately 137 feet above Mean Sea Level near the western property line to approximately 155 feet above MSL in the building pad. GENERAL GEOLOGY AND SUBSURFACE CONDITIONS GEOLOGIC SETTING AND SOIL DESCRIPTION: The subject site is located in the Coastal Plains Physiographic Province of San Diego County. Based upon the results of our limited exploration and analysis of readily available, pertinent geologic literature, it was determined that the site is underlain by Quaternary -age terrace deposits overlain by artificial fill in the western portion of the building pad. These materials are described below: ARTIFICIAL FILL (Qaf): Man - placed fill soil was encountered in our two exploratory test pits excavated in the western portion of the building pad. The thickness of the fill layer encountered in our test pits ranged from approximately two feet to three and one -half feet. It should be noted, however, that fill material was not encountered in our test pits excavated in the eastern portion of the building pad, and as such, the thickness of the fill layer is expected to taper to zero near the central portion of the existing building pad. In general, the fill material consists of medium brown, silty sand (SM) and grayish- brown, clayey sand (SC). The encountered fill was noted to be generally moist and medium dense in consistency. TOPSOIL: A relatively thin veneer of native topsoil was encountered below the fill in Test Pit P -3. This layer of topsoil was approximately six inches thick and consisted of brown, clayey sand (SC), that was moist and medium dense. TERRACE DEPOSITS (Qt): Quaternary -age terrace deposits were encountered in each of our exploratory test pits. The terrace deposits were encountered below the fill layer in the western C` E 200.563.1 October 26, 2000 Page No. 4 portion of the building pad and near the surface in the eastern portion. The terrace deposits typically consisted of reddish - brown, silty sand (SM), and were generally moist and dense in consistency. GROUNDWATER No groundwater was encountered in our exploratory test pits and we do not expect any groundwater problems to develop due to the proposed construction provided proper drainage is maintained on the site. TECTONIC SETTING: It should be noted that much of Southern California, including the San Diego County area, is characterized by a series of Quaternary -age fault zones that consist of several individual, en echelon faults that generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as "active" according to the criteria of the California Division of Mines and Geology. Active fault zones are those that have shown conclusive evidence of faulting during the Holocene Epoch (the most recent 11,000 years). A review of available geologic maps indicates that the active Rose Canyon Fault Zone is located approximately 5 kilometers west of the subject site. Other active fault zones in the region that could possibly affect the site include the Coronado Bank and San Clemente Fault Zones to the southwest and the Elsinore, San Jacinto, and San Andreas Fault Zones to the northeast. GEOLOGIC HAZARDS GENERAL: No geologic hazards of sufficient magnitude to preclude development of the site as we presently contemplate it are known to exist. In our professional opinion and to the best of our knowledge, the site is suitable for the proposed development. GROUND SHAKING: A likely geologic hazard to affect the site is ground shaking as result of movement along one of the major active fault zones mentioned above. The maximum bedrock accelerations that would be attributed to a maximum magnitude earthquake occurring along the nearest fault segments of selected fault zones that could affect the site are summarized in the following Table I. CWE 200.563.1 October 26, 2000 Page No. 5 TABLE I Maximum Maximum Fault Zone Distance Magnitude Bedrock Earthquake Acceleration Rose Canyon 5 km 6.9 Magnitude 0.42 g Coronado Bank 15 km 7.4 Magnitude 0.19 g Elsinore 43 km 7.1 Magnitude 0.12 Earthquake Valley 68 km 6.5 Magnitude 0.06 San Jacinto 80.2 km 7.2 Magnitude 0.08 g Probable ground shaking levels at the site could range from slight to moderate, depending on such factors as the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience the effects of at least one moderate to large earthquake during the life of the proposed structure. SEISMIC DESIGN PARAMETERS: Based on a maximum magnitude (Mmax) earthquake of 6.9 along the nearest portion of the Rose Canyon Fault Zone, the Maximum Bedrock Acceleration at the site would be approximately 0.42 g. For structural design purposes, a damping ratio not greater than 5 percent of critical dampening, and Soil Profile Type SD are recommended (UBC Table 16 -J). Based upon the location of the site of at approximately 5 kilometers from the Rose Canyon Fault (Type B Fault), Near Source Factors N equal to 1.0 and N, equal to 1.2 are also applicable. These values, along with other seismically related design parameters from the Uniform Building Code (UBC) 1997 edition, Volume II, Chapter 16, utilizing a Seismic Zone 4 are shown in Table II, presented below. TABLE II UBC — Chapter 16 Seismic Recommended Table No. Parameter Value 16 -I Seismic Zone Factor Z 0.40 16-J Soil Profile Type SD 16-Q Seismic Coefficient C 0.44 Na 16 -R Seismic Coefficient C,, 0.64 N,- 16-S Near Source Factor N 1.0 16 -T Near Source Factor N, 1.2 16 -U Seismic Source Type B LANDSLIDE POTENTIAL AND SLOPE STABILITY: As part of this investigation the reviewed the publication, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area" by Tan, 1995. This reference is a comprehensive study that classifies San Diego County into areas of relative landslide susceptibility. The subject site is located in Subarea 2. Slopes within the 2 classification include gentle to moderate slopes. CWE 200.563.1 October 26, 2000 Page No. 6 Landslides and other slope failures are rare within this area, although slope hazards are possible on some steeper slopes within the area or along its borders. Based on the results of our site - specific investigation, it is our opinion that the potential for both shallow and deep - seated landsliding is considered to be very low. LIQUEFACTION: The near - surface native materials at the site are not subject to liquefaction due to such factors as soil density, grain -size distribution, and the absence of shallow groundwater conditions. FLOODING: The site is located outside the boundaries of both the 100 -year and the 500 -year flood plains according to the maps prepared by the Federal Emergency Management Agency. TSUNAMIS: Tsunamis are great sea waves produced by submarine earthquakes or volcanic eruptions. Due to the site's location, the site will not be affected by a tsunami. SEICHES: Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs. Due to the site's location, it will not be affected by seiches. CONCLUSIONS In general, no geotechnical conditions were encountered that would preclude the construction of the proposed new residence and improvements, provided the recommendations contained in this report are followed. The western portion of the existing building pad is underlain by loose to medium dense fill material. The rest of the lot is underlain by dense terrace deposits capped with a relatively thin layer of topsoil. The fill material and topsoil are not considered to be suitable to support settlement- sensitive structures and improvements in their present condition, and will need to be removed and replaced as compacted structural fill. In addition, we expect that a cut /fill transition line will cross the central portion of the new building pad. In order to provide uniform support for the structure, the cut portion of the building pad will also need to be undercut and the excavated soils replaced as compacted structural fill. Specific site preparation and foundation recommendations are presented in the following section of this report. RECOMMENDATIONS GRADING AND EARTHWORK GENERAL: All grading should conform with the guidelines presented in Appendix Chapter A33 of the Uniform Building Code, the minimum requirements of the City of Encinitas, and the Recommended Grading C`}UE 200.563.1 October 26, 2000 Page No. 7 Specifications and Special Provisions attached hereto, except where specifically superseded in the text of this report. Prior to grading, a representative of Christian Wheeler Engineering should be present at the preconstruction meeting to provide additional grading guidelines, if necessary, and to review the earthwork schedule. OBSERVATION OF GRADING: Continuous observation by Christian Wheeler Engineering is essential during the grading operation to construct the building pad in order to confirm the conditions anticipated by our investigation, to allow adjustments in design criteria to reflect the actual field conditions exposed, and to determine that the grading proceeds in general accordance with the recommendations contained herein. CLEARING AND GRUBBING: Site preparation should begin with the demolition of the existing structures and the removal of all vegetation, concrete, and other deleterious materials and hard construction debris from the portion of lot that will be graded and that will receive improvements. This should include all root balls from the trees to be removed and all significant root material. The resulting materials should be disposed of off -site. SITE PREPARATION: After clearing and grubbing, site preparation should begin the removal from areas to receive fill and /or settlement- sensitive improvements of the existing fill and topsoils. The existing fill and topsoil should be removed to the contact with competent underlying formational material. We expect that the maximum depth of removal will be on the order of about five feet. However, it should be realized that localized deeper areas may be encountered. In addition, site preparation should include mitigation for the cut /fill transition that traverses the building pad as discussed in the following section. The bottom of the removal area should be observed and approved by a member of our staff prior to the placement of fill in order to verify that additional removal is not necessary. The on -site soils are considered suitable for use as structural fill. Prior to replacing the excavated soils, the soils exposed at the bottom of the excavation should be processed in accordance with the following section of this report. The soil should be placed in the excavation in accordance with the "Compaction and Method of Filling" section of this report, which follows hereinafter. At this time, it is our opinion that no other site preparation will be necessary other than processing the areas to receive fill material as recommended in the following section. CUT /FILL TRANSITION: Where the building pad will be traversed by a cut /fill transition line, the cut portion of the building pad should be undercut at least three feet. The undercut portion should be extended horizontally at least five feet outside the perimeter of the foundations for the proposed structure. The bottom of the overexcavated areas should be sloped in such a manner that water does not become trapped in the overexcavated zone. Prior to replacing the excavated materials, the soils exposed at the bottom of the CWE 200.563.1 October 26, 2000 Page No. 8 excavation should be scarified to depth of six inches, moisture conditioned and compacted to at least 90 percent relative compaction. PROCESSING OF FILL AREAS: Prior to placing any fill soils or constructing any new improvements in areas that have been cleaned out to receive Fill, the exposed soils should be scarified to a depth of 12 inches, moisture conditioned, and compacted to at least 90 percent relative compaction. In areas to support fill slopes, keys should be cut into the competent supporting materials. The keys should be at least ten feet wide and be sloped back into the hillside at least two - percent. The keys should extend at least one foot into the competent supporting materials. No other special ground preparation is anticipated at this time. COMPACTION AND METHOD OF FILLING: All structural fill placed at the site should be compacted to a relative compaction of at least 90 percent of maximum dry density as determined by ASTM Laboratory Test D1557 -91. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick, with each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by our soil technicians or project geologist. Fill material should be free of rocks or lumps of soil in excess of twelve inches in maximum dimension. However, in the upper two feet of pad grade, no rocks or lumps of soil in excess of six inches should be allowed. Fills should be benched into all temporary slopes and into competent natural soils when the natural slope is steeper than an inclinatio of 5:1 (ho rizontal to vertical). Keys should be constructed at the toe of all fill slopes as recommended above. 7 11 Utility trench backfill within five feet of the proposed structures and beneath all pavements and concrete flatwork should be compacted to a minim of 90 percent of its maximum dry density. FILL SLOPE CONSTRUCTION: Fill slopes may be constructed at an inclination of 2:1 or flatter (horizontal to vertical). Compaction of slopes should be performed by back - rolling with a sheepsfoot compactor at vertical intervals of four feet or less as the fill is being placed, and track - walking the face of the slope when the slope is completed. As an alternative, the fill slopes may be overfilled by at least three feet and then cut back to the compacted core at the design line and grade. Keys should be made at the toe of fill slopes in accordance with the recommendations presented above under "Compaction and Method of Filling." IMPORTED FILL MATERIAL: It appears that some amount of fill material will need to be imported to grade the site to receive the proposed improvements. Any imported fill material should be evaluated and approved by the Geotechnical Consultant prior to being imported. At least two working days notice of a CWE 200.563.1 October 26, 2000 Page No. 9 potential import source should be given to the Geotechnical Consultant so that appropriate testing can be accomplished. The type of material considered most desirable for import is a nondetrimentally expansive granular material with some silt or clay binder. SURFACE DRAINAGE: Pad drainage should be designed to collect and direct surface water away from proposed structures and toward approved drainage areas. In general, we recommend that the ground adjacent to structures slope away at a gradient of at least two percent. Densely vegetated areas where runoff can be impaired should have a minim gradient of at least five percent within the first five feet from the structure. GRADING PLAN REVIEW: The final grading plans should be submitted to this office for review in order to ascertain that the recommendations of this report have been implemented, and that no additional recommendations are needed due to changes in the anticipated development plans. FOUNDATIONS GENERAL: Based on our investigation, it is our opinion that proposed single- family residence may be supported by conventional shallow spread footings. New spread footings supporting the proposed two -story structure should be embedded at least 18 inches below finish pad grade. Continuous footings should have a minim width of 12 inches. Isolated spread footings should have a minim width of 24 inches. BEARING CAPACITY: New conventional spread footings with the above minim dimensions may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot. This value may be increased by one -third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING REINFORCEMENT: The project structural engineer should provide reinforcement requirements for foundations. However, based on soil conditions, we recommend that the minim reinforcing for continuous footings consist of at least one No. 5 bar positioned three inches above the bottom of the footing and one No. 5 bar positioned two inches below the top of the footing. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be and 0.35. The passive resistance may be considered to be equal to an equivalent fluid weight of 350 pounds per cubic foot. This assumes the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one - third. CWE 200.563.1 October 26, 2000 Page No. 10 SETTLEMENT CHARACTERISTICS: The anticipated total and /or differential settlement is expected to be less than about one -half inch for new foundations, provided the recommendations presented in this report are followed. It should be recognized that minor cracks normally occur in concrete slabs and foundations due to shrinkage during curing or redistribution of stresses, therefore some cracks may be anticipated. Such cracks are not necessarily an indication of excessive vertical movements. EXPANSIVE CHARACTERISTICS: The foundation soils were found to have a low expansive potential. The recommendations presented in this report reflect this condition. FOUNDATION PLAN REVIEW: The foundation plans should be submitted to this office for review in order to ascertain that the recommendations of this report have been implemented, and that no additional recommendations are needed due to changes in the anticipated construction. FOUNDATION EXCAVATION OBSERVATION: All excavations for new foundations should be observed by the Christian Wheeler Engineering prior to placing concrete to determine if the foundation recommendations presented herein are followed. All footing excavations should be excavated neat, level, and square. All loose or unsuitable material should be removed prior to the placement of concrete. ON -GRADE SLABS INTERIOR FLOOR SLAB: It is our opinion that the minim floor slab thickness should be four inches. The floor slab should be reinforced with at least No. 3 bars placed at 18 inches on center each way. The slab reinforcing bars should extend at least six inches into the perimeter footings. Slab reinforcing should be supported by chairs and be positioned at mid - height in the floor slab. MOISTURE PROTECTION FOR INTERIOR SLABS: Where the concrete on -grade floor slabs will support moisture - sensitive floor covering, it should be underlain by a moisture barrier. We recommend that the minimum configuration of the subslab moisture barrier consist of a four - inch -thick blanket of coarse, clean sand. The moisture barrier material should have less than ten percent and five percent passing the No. 100 and No. 200 sieves, respectively. A visqueen vapor barrier should be placed in the center of the moisture protection blanket. Our experience indicates that this moisture barrier should allow the transmission of from about six to twelve pounds of moisture per 1000 square feet per day through the on -grade slab. This may be an excess amount of moisture for some types of floor covering. If additional protection is considered necessary, additional recommendations can be provided. CWE 200.563.1 October 26, 2000 Page No. 11 EXTERIOR CONCRETE FLATWORK: Exterior slabs should have a minimum thickness of four inches. Reinforcement and control joints should be constructed in exterior concrete flatwork to reduce the potential for cracking and movement. Joints should be placed in exterior concrete flatwork to help control the location of shrinkage cracks. Spacing of control joints should be in accordance with the American Concrete Institute specifications. When patio, walks and porch slabs abut perimeter foundations they should be doweled into the footings. EARTH RETAINING WALLS FOUNDATIONS: The recommendations provided in the "Foundations" section of this report are also applicable to retaining walls. PASSIVE PRESSURE: The passive pressure for the prevailing soil conditions may be considered to be 350 pounds per square foot per foot of depth. This pressure may be increased one -third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be 0.35 for the resistance to lateral movement. When combining frictional and passive resistance, the friction should be reduced by one - third. The upper 12 inches of exterior retaining wall footings should not be included in passive pressure calculations where abutted by landscaped or unpaved areas. EQUIVALENT FLUID PRESSURES: The active soil pressure for the design of unrestrained earth retaining structures with level backfill may be assumed to be equivalent to the pressure of a fluid wei ghing 35 pounds per cubic foot. This pressure does not consider any surcharge. If any are anticipated, this office should be contacted for the necessary increase in soil pressure. These values assume a drained backfill condition. WATERPROOFING AND SUBDRAIN OBSERVATION: The project architect should provide waterproofing details. The geotechnical engineer should be requested to verify that waterproofing has been properly applied, however, this will not be done unless specifically asked to do so. Also, a suggested wall subdrain detail is provided on the attached Plate Number 6. We recommend that the Geotechnical Consultant be retained to observe all retaining wall subdrains to verify proper construction. BACKFILL: All backfill soils should be compacted to at least 90 percent relative compaction. It is anticipated that the on -site soils are suitable for use a backfill material, however, any expansive or clayey soils should not be used for backfill material. The wall should not be backfilled until the masonry has reached an adequate strength. C`Y/E 200.563.1 October 26, 2000 Page No. 12 LIMITATIONS REVIEW, OBSERVATION AND TESTING The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the geotechnical engineer and engineering geologist so that they may review and verify their compliance with this report and with the Uniform Building Code. It is recommended that Christian Wheeler Engineering be retained to provide continuous soil engineering services during the earthwork operations. This is to verify compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. UNIFORMITY OF CONDITIONS The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and /or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the geotechnical engineer so that he may make modifications if necessary. CHANGE IN SCOPE This office should be advised of any changes in the project scope or proposed site grading so that we may determine if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. TIME LIMITATIONS The findings of this report are valid as of this date. Changes in the condition of a property can, however, occur with the passage of time, whether they be due to natural processes or the work of man on this or adjacent properties. In addition, changes in the Standards -of- Practice and /or Government Codes may occur. CkVE 200.563.1 October 26, 2000 Page No. 13 Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and recommendations. PROFESSIONAL STANDARD In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our test pits, surveys, and explorations are made, and that our data, interpretations, and recommendations be based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. CLIENT'S RESPONSIBILITY It is the responsibility of the client, or their representatives, to ensure that the information and recommendations contained herein are brought to the attention of the structural engineer and architect for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to insure that the contractor and his subcontractors carry out such recommendations during construction. FIELD EXPLORATIONS Four subsurface explorations were made at the locations indicated on the site plan included herewith as Plate Number 1 on October 5, 2000. These explorations consisted of manually excavated test pits. The fieldwork was conducted by or under the observation of our engineering geology personnel. The explorations were carefully logged when made. The test pit logs are presented on the following Plate Numbers 2 through 5. The soils are described in accordance with the Unified Soils Classification. In addition, a verbal textural description, the wet color, the apparent moisture and the density or consistency are provided. The density of granular soils is given as either very loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard. CWE 200.563.1 October 26, 2000 Page No. 14 Bulk samples of disturbed soil were collected in bags from the pit excavation. In addition, "undisturbed" samples of representative soils were obtained from the borings and returned to the laboratory for testing. The undisturbed samples from the borings were obtained by driving a 2 -3/8 inch ID split -tube sampler ahead of the auger using a 140 -pound weight free falling a distance of 30 inches. The number of blows to drive the sampler twelve inches was recorded and this number is presented on the boring logs as the "Penetration Resistance ". LABORATORY TESTING Laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of the tests performed is presented below: a) CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System. b) MOISTURE - DENSITY: In -place moisture contents and dry densities were determined for representative soil samples. This information was an aid to classification and permitted recognition of variations in material consistency with depth. The dry unit weight is determined in pounds per cubic foot, and the in -place moisture content is determined as a percentage of the soil's dry weight. The results of these tests are summarized in the test pit logs. c) COMPACTION TEST: The maximum dry density and optimum moisture content of a typical soil were deternined in the laboratory in accordance with ASTM Standard Test D- 1557 -91. The results of this test are presented on Plate Number 7. d) DIRECT SHEAR TEST: Direct shear tests were performed to determine the failure envelope based on yield shear strength. The shear box was designed to accommodate a sample having a diameter of 2.375 inches or 2.50 inches and a height of 1.0 inch. Samples were saturated and tested at different vertical loads. The shear stress was applied at a constant rate of strain of approximately 0.05 inch per minute. The results of these tests are presented on the attached Plate Number 7. e) GRAIN SIZE DISTRIBUTION: The grain size distribution was determined from representative samples of the topsoil and Bay Point Formation in accordance with ASTM D422. The results of these tests are presented on Plate Number 7. LOG OF TEST PIT NUMBER P -1 Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project .Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A SAMPLES U c) W H SUMMARY OF SUBSURFACE CONDITIONS N Z off c� CIO ° Q Terrace Depo sits (Qt): Reddish - brown, SILTY SAND (SM), humid, dense. CK 3.7 108.9 SA 1 CK MD 2 CK 6.0 111.2 DS CK Material becomes moist CK 8.6 1126 3 4 Test pit terminated at 3 feet. 5 6 7 8 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hymettus Avenue, Encinitas, California CHRISTIAN WHEELER BY: SCC DATE: 10/26/00 ENGINEERING [ JOB NO.: 200.563 1PLATE NO.: 2 LOG OF TEST PIT NUMBER P -2 Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A SAMPLES O `J H SUMMARY OF SUBSURFACE CONDITIONS a 2 H Z W�W Q a CIO O E� O CIO Q C7 Terrace Deposits Qj): Reddish- brown, SILTY SAND (SNv , moist, d dense, medium- to coarse - grained. CK 4.7 113.2 CK 2 CK 4.7 107.9 CK 3 '' CK 4.7 119.8 4 Test pit terminated at 3 feet. 5 6 7 8 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1 1024 Hymettus Avenue, Encinitas, California CHRIS WHEELER BY: SCC DATE: 10/26/00 E N G I N E E R I N G JOB NO.: 200.563 1PLATE NO.: 3 LOG OF TEST PIT NUMBER P -3 Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A SAMPLES Y C) W W O f-, SUIVUvIARY OF SUBSURFACE CONDITIONS a 2 D Z U E/) Q o C7 � Q Fill a • Medium brown, SILTY SAND (SM), moist, loose. CK 1 CK 2 . ......................................................................................................................... .............................�K ......... ....... ......... ......... Grayish -brown to reddish- brown, CLAYEY SAND (SC), moist CK 3 medium dense. CK Topsoil: Brown, SANDY CLAY (SC), moist, loose. us 4 Terrace Deposits (t): Reddish- brown, SILTY SAND (SM), moist CK 9.8 115.6 dense, medium- to coarse - grained. 5 Test pit terminated aI 4' /z feet. 6 7 8 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hymettus Avenue, Encinitas, California CHRIS7 WHEELER, BY: SCC DATE: 10/26/00 ENGINEERING JOB NO.: 200.563 1PLATE NO.: 4 LOG OF TEST PIT NUMBER P -4 Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A SAMPLES 0 � O O SUMMARY OF SUBSURFACE CONDITIONS a Q Z W W Z O f Q O O Fill :Reddish - brown, SILTY SAND (SN4), moist, loose. 1 2 CK Terrace Deposits lOtllOtl: Reddish- brown, SILTY SAND (SM), moist, 3 dense, medium- to coarse - grained. CK 5.8 106.7 4 Test pit terminated at 3 feet. 5 6 7 8 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hymettus Avenue, Encinitas, California CHRISTIAN WHEELER BY: SCC DATE: 10/26/00 ENGINEERING JOB NO.: 200.563 PLATE NO.: 5 i I + I � I � - —�% SLOPE MINIMUM _ _ 6" MIN 6" MAX ' e WATERPROOF BACK OF WALL e e PER ARCHITECT'S SPECIFICATIONS 0 e 3/4 WCH CRUSHED ROCK or o MIRADRAIN 6000 or EQUIVALENT GEOFABRIC BETWEEN ROCK AND SOIL �o ° TOP OF GROUND or CONCRETE SLAB 6 MIN I ` I M-INIMUM 4 INOH WAMETER PERFORA` ti) PIPE RETAINING WALL SUBDRAIN DETAIL No Scale Christian Wheeler Engineering Job Number: 200.563.1 Date: OCTOBER 26. 2000 Plate Number: 6 LABORATORY TEST RESULTS PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYMETTUS AVENUE ENCINITAS. CALIFORNIA DIRECT SHEAR TEST Sample Number Test Pit P -1 @ 1 /2' -3' Description Remolded to 90 Angle of Internal Friction 32 degrees Apparent Cohesion 300 psf COMPACTION TEST Sample Number. Test Pit P -1 @ 1 /2' -3' Sample Description: Reddish - Brown, Silty Sand (SM) Optimum Moisture: 8.1 percent Maximum Density: 131.8 pcf GRAIN SIZE DISTRIBUTION Sample Number Test Pit P -1 @ 1 /2 ' - 3' Sieve Size Percent Passing #4 #8 100 #16 99 #30 92 #50 52 #100 29 #200 29 Classification SM C`VE 200.563 October 26, 2000 Plate No. 7 CWE 200.563 October 26, 2000 Appendix A, Page A -1 REFERENCES Anderson, J.G.; Rockwell, R.K and Agnew, D.C., 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region, Earthquake Spectra Volume 5, No. 2, 1989. California Division of Mines and Geology, 1998, Maps of Known Active Fault Near Source -Zones in California and Adjacent Portions of Nevada. Jennings, C.W., 1975, Fault Map of California, California Division of Mines and Geology, Map No. 1, Scale 1:750,000. Kern, P., 1989, Earthquakes and Faults in San Diego County, Pickle Press, 73 pp. Mualchin, L. and Jones, A.L., 1992, Peak Acceleration from Maximum Credible Earthquakes in California (Rock and Stiff -Soil Sites) California Division of Mines and Geology Open -File Report 92 -1. Wesnousky, S.G., 1986, "Earthquakes, Quaternary Faults, and Seismic Hazards in California ", in Journal of Geophysical Research, Volume 91, No. B12, pp 12,587 to 12,631, November 1986. TOPOGRAPHIC MAPS County of San Diego, 1979, Map Sheet 326 -1677; Scale: 1 inch = 200 feet U.S. Geological Survey, 1968 (Photo- revised 1975), T/2 Minute Topographic Map, Encinitas, CA Quadrangle, scale 1:24,000. CWE 200.563.1 October 26, 2000 Appendix B, Page B -1 RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYMETTUS AVENUE ENCINITAS, CALIFORNIA GENERAL INTENT The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the accepted plans. The recommendations contained in the preliminary geotechnical investigation report and /or the attached Special Provisions are a part of the Recommended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for which they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written communication signed by the Geotechnical Engineer. OBSERVATION AND TESTING Christian Wheeler Engineering shall be retained as the Geotechnical Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his representative provide adequate observation so that he may provide his opinion as to whether or not the work was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical Engineer and to keep him appraised of work schedules, changes and new information and data so that he may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer shall be contacted for further recommendations. If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc., construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this work. Tests used to determine the degree of compaction should be performed in accordance with the following American Society for Testing and Materials test methods: CWE 200.563.1 October 26, 2000 Appendix B, Page B -2 Maximum Density & Optimum Moisture Content - ASTIVI D- 1557 -91 Density of Soil In -Place - ASTM D- 1556 -90 or ASTM D -2922 All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM testing procedures. PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of. All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6 inches, brought to the proper moisture content, compacted and tested for the specified minim degree of compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground which is defined as natural soil which possesses an in -situ density of at least 90 percent of its maximum dry density. When the slope of the natural ground receiving fill exceeds 20 percent (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm competent formational soil. The lower bench shall be at least 10 feet wide or 1 -1/2 times the equipment width, whichever is greater, and shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the Geotechnical Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedure should be backfilled with acceptable soil that is compacted to the requirements of the Geotechnical Engineer. This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Geotechnical Engineer so that he may determine if any special recommendation will be necessary. All water wells which will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3 CWE 200.563.1 October 26, 2000 Appendix B, Page B -3 feet below the bottom of footing whichever is greater. The type of cap will depend on the diameter of the well and should be determined by the Geotechnical Engineer and /or a qualified Structural Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the Geotechnical Engineer before being brought to the site. PLACING AND COMPACTION OF FILL Approved fill material shall be placed in areas prepared to receive fill in layers not to exceed 6 inches in compacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minim degree of compaction with equipment of adequate size to economically compact the layer. Compaction equipment should either be specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minim degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non- structural fills is discussed in the geotechnical report, when applicable. Field observation and compaction tests to estimate the degree of compaction of the fill will be taken by the Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the Geotechnical Engineer's discretion. When the compaction test indicates that a particular layer is at less than the required degree of compaction, the layer shall be reworked to the satisfaction of the Geotechnical Engineer and until the desired relative compaction has been obtained. C``UE 200.563.1 October 26, 2000 Appendix B, Page B -4 Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by sheepsfoot roller shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over -built and cut- back to finish contours after the slope has been constructed. Slope compaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative compaction of at least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions section of this specification. The compaction operation on the slopes shall be continued until the Geotechnical Engineer is of the opinion that the slopes will be surfiaally stable. Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to determine if the required compaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Geotechnical Engineer or his representative in the form of a daily field report. If the method of achieving the required slope compaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction is obtained, at no cost to the Owner or Geotechnical Engineer. CUT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Geotechnical Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of the controlling governmental agency. ENGINEERING OBSERVATION Field observation by the Geotechnical Engineer or his representative shall be made during the filling and compaction operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or CWE 200.563.1 October 26, 2000 Appendix B, Page B -5 the observation and testing shall release the Grading Contractor from his duty to compact all fill material to the specified degree of compaction. SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before acceptance of work. RECOMMENDED GRADING SPECIFICATIONS - SPECIAL PROVISIONS RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural ground, compacted fill, and compacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper six inches should be compacted to at least 95 percent relative compaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29 -C. OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil over 6 inches in diameter. Oversized materials should not be placed in fill unless recommendations of placement of such material is provided by the Geotechnical Engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and recompacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required. w CHRISTIAN WHEELER ENGINEERING REPORT OF GRADING OBSERVATIONS AND TESTING TURNER RESIDENCE 1024 HYMETTUS AVENUE ENCINITAS, CALIFORNIA PREPARED FOR: DAVID AND VICKI TURNER 1024 HYMETTUS AVENUE ENCINITAS, CALIFORNIA 92024 PREPARED BY: CHRISTIAN WHEELER ENGINEERING 4925 MERCURY STREET SAN DIEGO, CALIFORNIA 92111 4925 Mercury Street + San Diego, CA 92111 + 858 -496 -9760 + FAX 858- 496 -9758 W CHRISTIAN WHEELER E N G I N E E R I N G September 5, 2002 David and Vicki Turner CWE 200.563.3 1024 Hymettus Avenue Encinitas, California 92024 SUBJECT: REPORT OF GRADING OBSERVATIONS AND TESTING, PROPOSED TURNER RESIDENCE, 1024 HYMETTUS AVENUE, ENCINITAS, CALIFORNIA Reference: "Report of Preliminary Geotechnical Investigation, Proposed Single - Family Residence, 1024 Hymettus Avenue, Encinitas, California," by Christian Wheeler Engineering, dated October 26, 2000 Ladies /Gentlemen, In accordance with your request and with the requirements of Section 1701.5.13 of the Uniform Building Code, Christian Wheeler Engineering has prepared this report to summarize our observations of the earthwork operations at the subject site, and to present the results of relative compaction tests performed in the fills that were placed during the grading of the project. The observation and testing services addressed by this report were coordinated by Dirt Works, Inc. and were provided periodically during the period of July 24 through August 12, 2002. INTRODUCTION AND PROJECT DESCRIPTION SITE DESCRIPTION: The subject site is a rectangular shaped parcel with an area of approximately 0.65 acres, located to the west of Hymettus Avenue in the City of Encinitas. The site is bounded on the north, west and south with developed residential properties. Prior to the earthwork addressed by this report, the site supported a single story, single - family residence, detached garage, and associated landscape improvements. Topographically, the site was relatively level in the east portion of the parcel, and sloped gently to the west. The pre - existing structures were demolished and removed from the site prior to the commencement of the earthwork operations. 4925 Mercury Street ♦ San Diego, CA 92111 ♦ 858- 496 -9760 + FAX 858- 496 -9758 C %VE_ 200.563.3 September 6, 2002 Page 2 The soils encountered during the earthwork operations were generally as described in the referenced report. PROPOSED CONSTRUCTION: It is our understanding that the subject site is to be developed by the construction of a two story, single - family residence. VVe anticipate that the proposed structure will have conventional shallow foundations and on -grade concrete floors. PLAN REFERENCE: In order to augment our understanding of the designed configuration of the project, our firm was provided with an undated grading plan for the site prepared by Tait Consulting of Oceanside, California, bearing an approval date from the City of Encinitas of June 4, 2002. Plate No. 1 of this report is a reproduction of the plan, modified to show the approximate locations of our field tests and the relevant limits of contact with the encountered geologic units. SCOPE OF SERVICE Services provided by Christian Sheeler Engineering, Inc. during the course of the earthwork consisted of the following: • Participation in a pre - grading meeting to address the geotechnical aspects of the work and to coordinate our testing and observation services, • Periodic observation of the earthworking operations, • Providing Field recommendations for elements of the earthwork not specifically addressed by the referenced geotechnical report, • Recording the approximate elevations and limits of significant geotechnical elements, • Performance of relative compaction tests in the fills placed, • Performance of laboratory maximum density and optimum moisture determination tests on the soils encountered in the earthwork, and, • Preparation of this report. SITE PREPARATION AND GRADING GRADING CONTRACTOR: The earthwork addressed by this report was performed by Dirt ``Forks Grading, Contractor's License No. 617946. The primary equipment utilized by the contractor in the work consisted of a Caterpillar DAM crawler dozer and a Case 580SL backhoe. C"'1✓ 200.563.3 September 6, 2002 Page 3 SITE PREPARATION: As previously noted, the pre - existing structures and associated site improvements were demolished prior to the earthwork operations. The materials generated by the demolition operations were exported from the site. Relatively shallow existing fills and compressible surficial soils were then excavated from the areas to receive fills, and were stockpiled onsite for future placement as structural fill. Keyways were excavated into formational soils at the toe areas of the proposed west - facing fill slopes. The keyways were configured to dip slightly to the hillside, and the soils exposed at the floor of the keyways were scarified, watered, and compacted prior to the placement of fill. Sandy fill soils, obtained from the stockpiles, onsite cuts and an import source, were then placed in thin horizontal lifts, watered to near optimum moisture content, and compacted in -place to at least 90 percent of the maximum dry density by means of track- and /or wheel- rolling with the heavy construction equipment. TRANSITION UNDERCUTS: In order to lessen the potential for differential settlement which could occur due to the dissimilar characteristics of soils in `cut' and `fill' conditions, the cut portion of the proposed housepad was undercut. The undercuts extended to at least three feet below the designed finish -grade elevation. The floor of the undercut areas were prepared, and subsequent fills placed, in the manner described in the preceding paragraph. The approximate limits of the transition undercuts are shown on the attached plate No. 1. VERTICAL SEEPAGE PITS: In the course of the earthwork operations, two abandoned vertical seepage pits were encountered in the area southwest of the proposed residence. One of the pits was found to have been filled with rounded and semi- rounded cobblestones, and the other was empty. The empty pit was filled with lean cement /sand slurry and the other was capped with 12 inches of Portland cement concrete reinforced with No. 4 bars positioned 18 inches on- center, each way. The concrete cap extended beyond the circumference of the pit. The uppermost elevation of the slurry and concrete caps were maintained at least five feet below the finished grade elevation. FIELD AND LABORATORY TESTING FIELD TESTS: Field tests to measure the relative compaction of the fills were conducted in accordance with ASTT%I Test Designation D 2922 -91; "Standard Test Methods for Density of Soil and Soil- Aggregate in Place by Nuclear Methods." The locations of the field tests were selected by our technician in areas discerned to exhibit relative compaction that was generally representative of that attained in the fill. The results and approximate locations of the field tests are shown on the attached plates. C \ \ -'E 300.563.3 September 6, 3002 Page 4 LABORATORY TESTS: The maxvnum dry density and optimum moisture content of the predominate soils encountered in the earthwork were performed in our laboratory by ASThI Test Designation D 1557 -91, "Test Method for Laboratory Compaction Characteristics of Soil Using Modified Effort." The tests were conducted in accordance with the methodology prescribed for the grain -size distribution of the soils tested. The results of these tests are presented on the attached Plate No. 2. CONCLUSIONS GENERAL: It is the opinion of Christian Wheeler Engineering that the earthwork addressed by this report has been performed substantially in accordance with the recommendations presented in the referenced geotechnical report, the City of Encinitas grading requirements and the Uniform Building Code. This opinion is based upon our observations of the earthwork operations, the results of the density tests taken in the field, and the maximum density tests performed in our laboratory. It is our further opinion that the site is suitable for the proposed construction. Our recommendations for the minimum design of foundations for the proposed structure, originally presented in the referenced geotechnical report, are reproduced in the "Foundations" section of this report. REMAINING WORK: As of the date of this report, additional work remains to be done on the site for the backfilling of utility trenches and the preparation of the subgrade and courses in areas to be paved. Our firm should be contacted when these operations are performed so that we can verify their compliance with the applicable specifications. FOUNDATION RECOMMENDATIONS GENERAL: It is our opinion that the proposed structure may be supported by conventional continuous and spread footings. Specific details for the design of the foundations should be provided by the structural engineer for the project; however, the foundation design should incorporate the minimum recommendations presented in the following paragraphs. EXPANSION CHARACTERISTICS: The soils present within the zone of influence of die proposed foundations are considered as being non - detrimentally expansive, with an Expansion Index less than 50. The recommendations presented herein reflect this condition. C`NT- 200.5633 September 6, 2002 Page 5 CONVENTIONAL FOUNDATIONS: Conventional shallow spread footings supporting the proposed two- story, single - family residence should be founded at least 18 in below the lowest adjacent finished grade. Continuous footings should have a minimum width of 12 inches. Isolated spread footings should have a minimum width of 24 inches. BEARING CAPACITY: Conventional spread footings with the above recommended minimum dimensions may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot. This value may be increased by one -third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING REINFORCING: Based on the as- graded soil conditions, we recommend that the minim reinforcing for continuous footings consist of at least one No. 5 bar positioned three inches above the bottom of the footing and one No. 5 bar positioned two inches below the top of the footing. This reinforcement is based on soil characteristics and is not intended to be in lieu of reinforcement necessary to satisfy structural considerations. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be 0.35. The Passive resistance may be considered equal to an equivalent fluid weight of 350 pounds per cubic foot. This assumes the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one - third. FOOTING SETBACKS: If footings for structures are proposed adjacent to the top of slopes, we reconrunend that a minim horizontal setback from the outer edge of the footing to the adjacent slope face be provided. The minimum setback from the slope face recommended is 5 feet from slopes 0 to 15 feet high, 10 feet for slopes 15 to 30 feet high, and 15 feet for slopes over 30 feet. The building setback distance for the top of slopes may be modified by using deepened footings. Footing setback is measured form competent soil and should neglect any loose of soft native soils that may occur at the top of a natural slope. Footings planned under the specified setbacks should be provided specific review by the Geotechnical Consultant prior to construction. FOUNDATION OBSERVATION: In order to confirm that the footing excavations extend into a suitable bearing stratum and to verify that the footing dimensions and reinforcing steel schedules are in accordance with the minimum recommendations provided by the geotechnical engineer, Christian CWE 300.363.3 September 6, 2002 Page 6 Wheeler Engineering should be contacted to observe the excavations in advance of structural inspections that may be conducted or required by the Building Official. ON -GRADE SLAB RECOMMENDATIONS INTERIOR FLOOR SLABS: The minimum floor slab thickness should be not less than four inches. The floor slabs should be reinforced with at least No. 3 bars placed at 18 inches on center, each way, and the reinforcement should extend horizontally at least 6 inches into the footings. Slab reinforcing should be positioned on chairs or mortar blocks at mid - height in the floor slab. MOISTURE PROTECTION FOR INTERIOR SLABS: Where the on -grade concrete floor slabs will support moisture - sensitive floor covering, they should be underlain by a moisture barrier. We recommend that the minim configuration of the subslab moisture barrier consist of a four - inch -thick blanket of coarse, clean sand. The moisture barrier sand should have 100 percent of the material passing the No. 4 sieve and less than ten percent and five percent passing the No. 100 and No. 200 sieves, respectively. A visqueen vapor barrier should be placed in the center of the moisture protection blanket. Our experience indicates that this moisture barrier should allow the transmission of from about 6 to 12 pounds of moisture per 1,000 square feet per day through the on -grade slab. This may be an excess amount of moisture for some types of floor covering. If additional protection is considered necessary, additional recommendations can be provided. If the slab does not support moisture - sensitive flooring, the slab should be supported by at least ttvo in of coarse sand. EXTERIOR CONCRETE FLATWORK Exterior slabs should have a minimum thickness of four inches. Reinforcement and control joints should be constructed in exterior concrete flatwork to reduce the potential for cracking and movement. Joints should be placed in exterior concrete flatwork to help control the location of shrinkage cracks. Spacing of control joints should be in accordance with the American Concrete Institute specifications. EARTH RETAINING WALLS LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered 0.35. The passive resistance map be considered equal to an equivalent fluid weight of 350 pounds per cubic foot. This assumes the footings are cast tight against undisturbed soils. If a combination of the passive pressure CWT- 200.563.3 September 6, 2002 Page i and friction is used, the friction value should be reduced by one - third. The upper 12 inches of exterior footings should not be included in passive pressure calculations where abutted by landscape areas. ACTIVE PRESSURE: The active soil pressure for the design of unrestrained earth retaining structures with level backfill may be assumed to be equivalent to the pressure of a fluid weighing 30 pounds per cubic foot. An additional 13 pounds per cubic foot should be added to said value for 2:1 (horizontal to vertical) sloping backfill. These pressures do not consider any other surcharge. If any are anticipated, this office should be contacted for the necessary increase in soil pressure. These values assume a drained backfill condition. Waterproofing details should be provided by the project architect. BACKFILL: All backfill soils should be compacted to at least 90 percent relative compaction. Expansive or clayey soils should not be used for backfill material. The walls should not be backfilled until the masonry has reached an adequate strength. FACTOR OF SAFETY: The above values, with the exception of the allowable soil friction coefficient, do not include a factor -of- safety. Appropriate factors -of- safety should be incorporated into the design to prevent the walls from overturning and sliding. LIMITATIONS The descriptions, conclusions and opinions presented in this report pertain only to the work performed on the subject site during the period from July 24 to August 12, 2001. As limited by the scope of the services which we agreed to perform, the conclusions and opinions presented herein are based upon our observations of the work and the results of our laboratory and field tests. Our services were performed in accordance with the currently accepted standard of practice in the region in which the earthwork was performed, and in such a manner as to provide a reasonable measure of the compliance of the described work with applicable codes and specifications. `With the submittal of this report, no warranty, express or implied, is given or intended with respect to the services performed by our firm, and our performance of those services should not be construed to relieve the grading contractor of his responsibility to perform his work to the standards required by the applicable building codes and project specifications. C \VE 200.563.3 September 6, 2002 Page 8 Christian Wheeler Engineering sincerely appreciates the opportunity to provide professional service on this project. If you should have any questions after reviewing this report, please do not hesitate to contact our firm. Respectfully submitted, CHRISTLNN WHEELER ENGINEERING 1 I ougl`s cks, Supervisor Q �p¢ESSI OQ�� N CHq�sj,�y4 CM c No. GE215 Uj Cr Exp 9-30 -05 Charles H. Christian, R.G.E. 00215 * �FOrECMN�c CHC /DH: dh O FCA1 -�� cc: (6) Submitted SUMMARY OF TESTS Project: Turner Residence 1L�SS GR,- DING Relative Comp action Tests ASTM D2922 -91 Test No. Date Location Elev. Soil Type Moisture Dry \ lax. % Rel. (feet) ( %) Density Density Comp. 1 7/29/2002 Keyway Fill - West End 138.5 ' 2 15.3 108.6 12L3 89.5 _..._..._ ..,___._.... «._...__......___.. ..__.___...._........_. d._..._...�__..........__...._. 2 12 4 116.5 i 121.3 96.0 -- 2 7/29/2002 Kevwav Fill - West End 138.5 , • 3 7/29/2002 Retest #1 '- 38.5 2 11.0 119.7 t 121.3 98.7 1 ......._._.___......_.� _._._...._...__.__....__. ._..___._.....__..__..._.._.__. __...__. ___...:..___......_____....... 4 7/29/2002 Keyway Fill - West End 138.5 2 .. 119.2 1 ... 98.3 5 7/29/2002 West End 140.5 2: �____3......1,1,9.2__R._..121.3 983 _.. _..__._ ..__.._ _....__..._w..._..�.__.._ ��_._._. 2.__..,._ »._.._7.5 � _120 � 121.3 99.3 6 7/29/2002 West End 0 ._ ..;_.._._.».._. _._..__.�..__..___..._._....... ..__.._ _,_.__..._............___.____. .._.._....__.._ _... _.__., 118 7 ! 21. 7 7/30/2002 West End of Lot 142.0 2 _...... 13 •.._,. _, ! ��:�.... _._»__......_......__._...:........._..................._.... _....__.......__....._._._.._,_ ... 7/30/_ 002......_ ............................................_......................:.............................................,.....,..............,......_.......... ....,......_....... ............ West End of Lot 142.0 2 8.1 F 119.4 121.3 98.4 8 ........1..............._......_ ....................._......................._................................... ......_...............y......., ............................ _.. ... . ....... .............................. ; 9 7/30/2002 .West End of Lot..._.__. _...... ...._........ 143 :...._._............. ..__.........x_......... ..: ... ._..1.17:5......._....... ...f_._ 9 6_�...... _.._....._..._ _.. _.._.___________- __......,............_......._. 10 7/30/2002 West End of Lot _ _........» 143: �..._..m._....._._�.. _ _. 8 �..._ .._:_.._. _.. 121 :3...w..._...__96.:...._....... _ ..__....___...__..�_...._.....w __......_..._.w_,.......___. West End 144.0 2 9.7 118.6 121.3 ? 97.8 11 7/31/2002 _ - . _. _ ___._ .._ ..__..._..___._..__.._. _____.__ _._....._.._...a...._._.___..__ _. _.___.__._......_._...__ .._.___._........_w. ___._____....... ..__....__.__,._..._____ __. ......._.,_.._. West End . 1161 121 3 1450 95.7 12 2 11.2 _.. 6 __. _ ....I._...___. 7/31/2002 s............__.._....._._,_ ...._...._.._.......__......... ._ _...._..__....____.._._._ _._..._ «_..._...._...... _._.__.. _ ...__..._.._........___. - __...._...___.._. 147.0 ' 2 9.7 119.7 121.3 '.... _.98.7 13 8/1/2002 ' `Vest End € ._........._.....__....__ w............_..._.._•___._..........._»_. i._............._........_............_._... w_....._....__._.........................._........._.._.._. a......_........__. ._.......... d._......._ ._......_.__..'r_.....__••_•___ W __.... i....._......_._.._._..._._ y...................__. ..._._.3._.._____.............. i 8/2/2002 Pad 149.0 2 9.9 120.3 121.3 99 ..........___._.....__. _ ___ _...._...___....._...._ _.._.....14 : »......_ ___...._.........._,_...........__....___.._...._........_•___-...__... ...__....__......_............. _....:. _ . _..._ ___ , _ _ _ ..._.... __ ..........» ... .._ 15 8/5/2002 Pad 151.0 2 .. _ ... 99.0 16 ! 8/5/2002 Pad .... ....._......._......_.,.._..__....._..._........_._. w...._..............._......._............... i......._._»_..._......._.... r.........__...._............ i_'"__._....._._.._... _.... i...._...__...........__...._ i-.._._...______. ._....4._..,.....__....__._.... ___.._._._........,..._..........__... ..._........__....___...,...... 154 0 3 ? 11 2 = 117.6 126.8 92.7 8/7/2002 3 10.1 ! 120.2 126.8 94.8 _.. ......_...._._...._...._....... Pa......_... _._- _.._.._....._........._•___ ......,.,.._ .....:........_..........._..................;...............__........ ..........._..._.._.... ......;_ - -- - -..._ ......_...... ....._._..... __. 17....._._.._.....__..._......_ Pad G. 155.7 18 8/7/2002 (F _ ............__..__._... �.....____._.____..___.._.._....._........___.._..__._...____....._ ........_..._...._.._.:.___..._ ..__...._.. 19 8/12/2002 Proposed House Area_...__., _.s...,....._FG.._.._........_w _�__._ .... _._.._�..� ._...._. »_.._1.18,?...._..._ 12 1 3 _ _._.........��.._...... .._.._..._........_.., .........._.._.............._ ._._._.., ....._..__....._.... 2 5.3 113.1 121.3 93.2 20 8/12/2002 Proposed House Pad Area ..__........................ FG............;................_.._..._.._..._... .. ... . ... _ ............. _..w..._ ....................................;....._.._......_......._... ..;.._.._.._.._.........._..... _........_ ............. ...... . ... . ..... .. ........ .. .............. . .__.,._.. ».........._.......... 21 8/12/2002 = Proposed House Pad area_....._.... FGw..._._.... �.._.__w............ 5: 5............. ........11.�:................_.. 1.21 _..... »...,_. � .:f._..._._ a ....... _. _. _.... ................ ..... ............ __..._.__... _._,_..__ _........:.__.._..... _. _ ,...... 111.3 121.3 91.8 22 8/12/2002 Proposed House Pad Area FG 2 5.2 TNL- �XI -MUTNI DRY DENSITY and OPTI-MUNi MOISTURE CONTENT ASTM 1557 -91 USCS Optimum Moisture Maximum Dry Soil Type Description Class N Density (pco 2 Reddish - brown, SILTY SAND SCI 10.0 121.3 3 Medium brown, SILTY SAND (Import) SIN 8.3 126.8 Plate 2 C %N'E 202.563.3 ENGINEERING SERVICES DEPARTMENT Capital Improvement Projects City Of District Support Services Encinitas Field Operations Subdivision Engineering Traffic Engineering Field Clearance to Allow Occupancy TO: Subdivision Engineering Public Service Counter FROM: Field Operations Private Contract Inspection RE: Building Permit No. - -- Name of Project ,.,, We J�is : err Name of Developer .A.,a e. I have inspected the site at je2y (address... number ...street ame ...suffix) and have determined that finish (precise) grading and (lot no.) (bldg. no.) any other related site improvements are substantially complete and that occupancy is merited. --- _�-- - y nature 67 Engi eri pectorl (D (Signature of Senior Civil Engineer, only if appropiate) (Date) Reference: Engineering Permit No. '7//�1•G r' Special Note: Please do not sign the "blue card" that is issued by Building Inspection Division and given to the developer. You are only being asked to verify field conditions. Office staff still has the responsibility to verify that compliance with administrative requirements is achieved, typically payment of impact fees or execution of documents. Return this form, if completed, to counter staff merely by dropping it in the slot labelled "final inspection" that is located between the desks of the engineering technicians. Also, please remember to do final inspections on the related engineering permits and return that paperwork, if completed. Thank you. JSG /field.doc I recycled paper - I - EL 760- 633 -2600 / FAX 760 - 633 -2627 505 S. Vulcan Avcnuc, Encinitas, California 92024 -3633 TDD 760 -633 -2700 w CHRISTIAN WHEELER- EN G IN EEK ING ' REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYMETTUS AVENUE ENCINITAS, CALIFORNIA PREPARED FOR: DAVID AND VICKI TURNER 1024 HYMETTUS AVENUE ' ENCINITAS, CALIFORNIA 92024 NO \N\- ENC,1N t \PSS ' PREPARED BY: CHRISTIAN WHEELER ENGINEERING 4925 MERCURY STREET ' SAN DIEGO, CALIFORNIA 92111 4925 Mercury Street + San Diego, CA 92111 + 858- 496 -9760 + FAX 858- 496 -9758 W CHRISTIAN WHEELER ENGINEERING ' October 26, 2000 ' David and Vicki Turner C%VUE 200.563.1 1024 Hymettus Avenue Encinitas, California 92024 SUBJECT: REPORT OF PRELIMINARY GEOTECHNICAL INVESTIGATION, PROPOSED SINGLE - FAMILY RESIDENCE, 1024 HYMETTUS, ' ENCINITAS, CALIFORNIA. Dear Mr. and Mrs. Turner: In accordance with your request and our Proposal dated September 13, 2000, we have completed a preliminary geotechnical investigation for the subject property. We are presenting herewith our findings and recommendations. In general, no geotechnical conditions were encountered that would preclude the construction of the proposed residence and associated improvements, provided the recommendations contained in this report are followed. The site is underlain by loose to medium dense, man - placed fill material in the east - central portion and dense terrace deposits in the eastern and western portions. The existing fill material is not considered suitable in its present condition to support settlement- sensitive structures and improvements and will need to be removed and replaced as compacted structural fill. In addition, it is anticipated that a cut /fill transition will run through the t new building pad. In order to provide a uniform mat of soil to support the proposed structure, it will be necessary to undercut the cut portion of the building pad and replace the excavated soil as compacted structural fill. ' If you have any questions after reviewing this report, please do not hesitate to contact our office. This opportunity to be of professional service is sincerely appreciated. f 7� Respectfully submitted, �' �'0 10'o �-A CERTIFIED } CHRISTIAN WHEELER ENGINEERING ! � 0 EN0. ° 1 GEOLOGIST J D pFESSiO,v� tp Exp. 10 -00 Charles H. Christian, R.G.E. #00215 1 r' y `,fz rds R. Burdett, C.E. . #1090 - <<' No. GE000215 CHC:CRB:scc 1`r } Exp. 9 -30 -01 Fy cc: (6) Submitted \cF �TECHN I PI 4925 Mercury Street + San Diego, CA 92111 + 858- 496 -9760 + FAX 858- 496 -9758 TABLE OF CONTENTS PAGE Introduction and Project Description ................................................................................ .............................. ProjectScope .......................................................................................................................... ..............................1 Findings.................................................................................................................................. ............................... 2 SiteDescription ............................................................................................................... .............................. General Geology and Subsurface Conditions ........................................................... ............................... 3 Geologic Setting and Soil Description ................................................................... ............................... 3 ArtificialFill ............................................................................................................. .............................. T ............................... 3 TerraceDeposits .................................................................................................... ............................... 3 Groundwater.............................................................................................................. ............................... 4 Tectonic Setting ......... ............................... 4 GeologicHazards .......................................................................................................... ............................... 4 1 General ........................................................................................................................ ............................... 4 GroundShaking ........................................................................................................ ............................... 4 SeismicDesign Parameters ...................................................................................... ............................... 5 Landslide Potential and Slope Stability 5 Liquefaction............................................................................................................... ............................... 6 Fl ............................... Tsunamis.................................................................................................................... ............................... 6 Seiches......................................................................................................................... ............................... 6 C ............................... 6 R ............................... 6 Gradingand Earthwork ................................................................................................ ............................... 6 General........................................................................................................................ ............................... 6 Observationof Grading ............................................................................................ .............................. Clearingand Grubbing ............................................................................................. ............................... 7 SitePreparation ......................................................................................................... ............................... 7 Cut /Fill Transition .................................................................................................... ............................... 7 Processingof Fill Areas ............................................................................................ ............................... 8 Compactionand Method of Filling ........................................................................ ............................... 8 FillSlope Construction ............................................................................................ ............................... 8 ImportedFill Material .............................................................................................. ............................... 8 SurfaceDrainage ....................................................................................................... ............................... 9 GradingPlan Review ................................................................................................ ............................... 9 Foundations.................................................................................................................... ............................... 9 General....................................................................................................................... ............................... 9 BearingCapacity ............................................................................. .............................. FootingReinforcement ............................................................................................ ............................... 9 ' Lateral Load Resistance ............................................................................................ ............................... 9 SettlementCharacteristics ........................................................................................ ............................. ExpansiveCharacteristics ........................................................................................ .............................10 FoundationPlan Review .......................................................................................... ............................. ` Foundation Excavation Observation ..................................................................... .............................10 On -Grade Slabs ............................................................................................................. ............................. InteriorFloor Slab .................................................................................................... ............................. ' Moisture Protection for Interior Slabs ................................................................ ............................... 0 ExteriorConcrete Flatwork ....................................................... ............................... ............................ EarthRetaining Walls ................................................................................................... ............................. ' C%VE 200.563 Single- Family Residence 1024 Hymettus Avenue Encinitas, California F ............................. PassivePressure ......................................................................................................... ............................. EquivalentFluid Pressures ...................................................................................... ............................. Waterproofing and Subdrain Observation ............................................................ .............................11 B ............................... Li ............................. Review Observation and Testing 12 Uniformityof Conditions ............................................................................................. ............................. Changein Scope ............................................................................................................ ............................. TimeLimitations ............................................................................................................ ............................. ' Professional Standard .................................................................................................... ............................. Client's Responsibility ...................................................................................... ............................. FieldExplorations ................................................................................................................. ............................. ' Laboratory Testing ................................................................................................................ ............................. ATTACHMENTS TABLES Table I Maximum Bedrock Accelerations, Page 5 Table II Seismic Design Parameters, Page 5 ' FIGURES Figure 1 Site Vicinity Map, Follows Page 1 PLATES I Plate 1 Site Plan Plates 2 -5 Test Pit Logs Plate 6 Suggested Subdrain Detail Plate 7 Laboratory Test Results APPENDICES Appendix A References Appendix B Recommended Grading Specifications: General Provisions ' CkVE 200.563 Single - Family Residence 1024 Hymettus Avenue Encinitas, California b W CHRISTIAN WHEELER ENGINEERING PRELIMINARY GEOTECHNICAL INVESTIGATION PROPOSED SINGLE - FAMILY RESIDENCE 1024 I IYMETTUS AVENUE ENCINITAS. CALIFORNIA INTRODUCTION AND PROJECT DESCRIPTION This report presents the results of our preliminary geotechnical investigation for a proposed single - family residence to be constructed at 1024 Hymettus Avenue, in the City of Encinitas, California. The location of the project site is shown on Figure Number 1. In order to augment our understanding of the proposed project, the client has provided our firm with an existing site plan for the project. This site plan has been modified by our firm to show the approximate locations of our subsurface explorations and to provide approximate geologic mapping of the site. The project site is an existing residential property that was developed sometime in the 1920's. The lot currently supports a single - family residence and detached garage with associated improvements. We understand that the existing improvements will be razed and that a new residence and driveway improvements are planned. The new residence will be a two -story structure and is expected to consist of wood -frame construction that will be supported by conventional shallow spread footings. The new residence is also expected to incorporate a concrete slab -on -grade floor system. In addition, we understand that the lot will be regraded in order to add more area to the western end of the building pad to accommodate the proposed improvements. As part of creating this additional area, a retaining wall will be constructed along a portion of the northern property line that will have a height of up to five feet. The grading is expected to consist of cuts and fills of less than ten feet from the existing grades. PROJECT SCOPE Our investigation consisted of: surface reconnaissance, subsurface explorations, obtaining representative disturbed and undisturbed samples, laboratory testing, analysis of the field and laboratory data, research of available geologic literature and geotechnical documents pertaining to the site, and preparation of this report. 1 More specifically, the intent of this investigation was to: ' a) Explore the subsurface conditions to the depths influenced by the proposed construction. 4925 Mercury Street + San Diego, CA 92111 + 858- 496 -9760 + FAX 858- 496 -9758 r . �: �... BaT •� § 4 �q �:� ' .. ° Y� � � .✓r - 6{ �.. � � ��d q •� y«�� P � y � iF i � �e a J.,� rn# A 4 Mm }, �3d. 1 �z � � '� ,a..� .� � v Imo` �. F �� i,.rycth. 9 1 .� x .d" _` 'a �i �' � Y'�4 #'`,a Srr g.nrarit w'as w v � V � s Ee 5k a 't ,+ p 4.s.i��j."�.-f.r &t�7 �� rr � '. - `s # � � �2� ��' �,} �� " � s�` ��`•�"'6� '� sa. e *, �, 3; .a' t � �� Mv j5., 'a � ° "`� �x U s "�t,'� IS ,. V�� W :e M� . _. IX.M r;z� .�Es'S -z ',qs'"`�� `� ., +u� � z �� '6 W 71 V " e " j# ti" rm z < , - mt- p Y. 73 p nm i A Ir _�` .ia•:, 5'7� ' }� a�"� t a�w � _, -�� 6 _ � ti ':_ems CWE 200.563.1 October 26, 2000 Page No. 2 1 b) Evaluate, by laboratory tests, the pertinent engineering properties of the various strata which may influence the proposed construction, including bearing capacities, expansive characteristics, and settlement potential. c) Describe the general geology at the site including possible geologic hazards that could have an effect on the site development, and provide the seismic design parameters as required by the most recent edition of the Uniform Building Code. d) Address potential construction difficulties that may be encountered due to soil conditions, groundwater or geologic hazards, and provide recommendations concerning these problems. e Develop oil e criteria for site p reparation and p recise g rading , neces P � g P P P g g� f) Provide recommendations for an appropriate foundation system for the type of structure anticipated and develop soil engineering design criteria for the recommended foundation design. g) Provide design parameters for "unrestrained" earth retaining walls. h) Present our professional opinions in this report, which includes in addition to our conclusions and recommendations, a plot plan, exploration logs and a summary of the laboratory test results. It was not within the scope of our services to perform laboratory tests to evaluate the chemical characteristics of the on -site soils in regard to their potentially corrosive impact to on -grade concrete and below grade improvements. If desired, we can obtain samples of representative soils and submit them to a chemical laboratory for analysis. Further, it should be understood Christian Wheeler Engineering does not practice corrosion engineering. If such an analysis is necessary, we recommend that the client retain an engineering firm that specializes in this field to consult with them on this matter. FINDINGS SITE DESCRIPTION I The subject site consists of a rectangular- shaped lot located westerly and adjacent to Hymettus Avenue, in the City of Encinitas, California. The site is identified by the address of 1024 Hymettus Avenue. Access to the site is afforded by Hymettus Avenue, which borders the site to the east. The site is bordered to the north, south, and west be developed residential properties. The lot was apparently developed sometime in the 1920's r CWT 200.563.1 October 26, 2000 Page No. 3 and existing improvements include a single -story, single - family residence and associated improvements in the central portion of the site. A small, single -story garage exists just north of the house. The house and garage are of wood -frame construction and are expected to be supported by conventional footings. Vegetation on the site consists primarily of lawn and typical landscaping flora with several small and large trees around the perimeter of the site and two relatively large trees at the west end of the building pad. Topographically, the building pad is relatively level and is the highest portion of the site. The site falls off towards Hymettus Avenue to the east with a gentle slope in the front and towards the west with a gentle to moderate slope behind the building pad. Based on a topographic survey prepared by John Douglas Baker, elevations at the site range from approximately 137 feet above Mean Sea Level near the western property line to approximately 155 feet above MSL in the building pad. GENERAL GEOLOGY AND SUBSURFACE CONDITIONS GEOLOGIC SETTING AND SOIL DESCRIPTION: The subject site is located in the Coastal Plains ' Physiographic Province of San Diego County. Based upon the results of our limited exploration and analysis of readily available, pertinent geologic literature, it was determined that the site is underlain by Quaternary -age terrace deposits overlain by artificial fill in the western portion of the building pad. These materials are described below. ARTIFICIAL FILL (Qaf): Man - placed fill soil was encountered in our two exploratory test pits excavated in the western portion of the building pad. The thickness of the fill layer encountered in our test pits ranged from approximately two feet to three and one -half feet. It should be noted, however, that fill material was not encountered in our test pits excavated in the eastern portion of the building pad, and as such, the thickness of the fill layer is expected to taper to zero near the central portion of the existing building pad. In general, the fill material consists of medium brown, silty sand (SM) and grayish- brown, clayey sand (SC). The encountered fill was noted to be generally moist and medium dense in consistency. TOPSOIL: A relatively thin veneer of native topsoil was encountered below the fill in Test Pit P -3. This layer of topsoil was approximately six inches thick and consisted of brown, clayey sand (SC), that was moist and medium dense. t TERRACE DEPOSITS (Qt): Quaternary-age terrace deposits were encountered in each of our exploratory test pits. The terrace deposits were encountered below the fill layer in the western CWE 200.563.1 October 26, 2000 Page No. 4 portion of the building pad and near the surface in the eastern portion. The terrace deposits typically consisted of reddish - brown, silty sand (SM), and were generally moist and dense in consistency. r GROUNDWATER No groundwater was encountered in our exploratory test pits and we do not expect any groundwater problems to develop due to the proposed construction provided proper drainage is maintained on the site. TECTONIC SETTING: It should be noted that much of Southern California, including the San Diego County area, is characterized by a series of Quaternary -age fault zones that consist of several individual, en echelon faults that generally strike in a northerly to northwesterly direction. Some of these fault zones (and the individual faults within the zone) are classified as "active" according to the criteria of the California Division of Mines and Geology. Active fault zones are those that have shown conclusive evidence of faulting during the Holocene Epoch (the most recent 11,000 years). A review of available geologic maps indicates that the active Rose Canyon Fault Zone is located approximately 5 kilometers west of the subject site. Other active fault zones in the region that could possibly affect the site include the Coronado Bank and San Clemente Fault Zones to the southwest and the Elsinore, San Jacinto, and San Andreas Fault Zones to the northeast. GEOLOGIC HAZARDS GENERAL: No geologic hazards of sufficient magnitude to preclude development of the site as we presently contemplate it are known to exist. In our professional opinion and to the best of our knowledge, the site is suitable for the proposed development. GROUND SHAKING: A likely geologic hazard to affect the site is ground shaking as result of movement along one of the major active fault zones mentioned above. The maximum bedrock accelerations that would be attributed to a maximum magnitude earthquake occurring along the nearest fault segments of selected fault zones i that could affect the site are summarized in the following Table I. CINE 200.563.1 October 26, 2000 Page No. 5 r TABLE I Maximum Maximum Fault Zone Distance Magnitude Bedrock Earthquake Acceleration Rose Canyon 5 km 6.9 Magnitude 0.42 g Coronado Bank 15 km 7.4 Magnitude 0.19 g Elsinore 43 km 7.1 Magnitude 0.12 Earthquake Valley 68 km 6.5 Magnitude 0.06 San Jacinto 80.2 km 7.2 Magnitude 0.08 g Probable ground shaking levels at the site could range from slight to moderate, depending on such factors as the magnitude of the seismic event and the distance to the epicenter. It is likely that the site will experience the effects of at least one moderate to large earthquake during the life of the proposed structure. SEISMIC DESIGN PARAMETERS: Based on a maximum magnitude (Mmax) earthquake of 6.9 along the nearest portion of the Rose Canyon Fault Zone, the Maximum Bedrock Acceleration at the site would be approximately 0.42 g. For structural design purposes, a damping ratio not greater than 5 percent of critical t . dampening, and Soil Profile Type SD are recommended (UBC Table 16 -J).' Based upon the location of the site of at approximately 5 kilometers from the Rose Canyon Fault (Type B Fault), Near Source Factors N, equal to 1.0 and N, equal to 1.2 are also applicable. These values, along with other seismically related design parameters from the Uniform Building Code (UBC) 1997 edition, Volume II, Chapter 16, utilizing a Seismic Zone 4 are 1 shown in Table II, presented below. TABLE II UBC — Chapter 16 Seismic Recommended Table No. Parameter Value 16 -I Seismic Zone Factor Z 0.40 16-J Soil Profile Type SD 16-Q Seismic Coefficient C 0.44 N, 16 -R Seismic Coefficient G, 0.64 N, 16-S Near Source Factor N, 1.0 16 -T Near Source Factor N, 1.2 16 -U Seismic Source Type B 1 LANDSLIDE POTENTIAL AND SLOPE STABILITY: As part of this investigation we reviewed the publication, "Landslide Hazards in the Northern Part of the San Diego Metropolitan Area" by Tan, 1995. This reference is a comprehensive study that classifies San Diego County into areas of relative landslide susceptibility. The subject site is located in Subarea 2. Slopes within the 2 classification include gentle to moderate slopes. CWE 200.563.1 October 26, 2000 Page No. 6 Landslides and other slope failures are rare within this area, although slope hazards are possible on some steeper slopes within the area or along its borders. Based on the results of our site - specific investigation, it is our opinion that the potential for both shallow and deep- seated landsliding is considered to be very low. LIQUEFACTION: The near - surface native materials at the site are not subject to liquefaction due to such factors as soil density, grain -size distribution, and the absence of shallow groundwater conditions. FLOODING: The site is located outside the boundaries of both the 100 -year and the 500 -year flood plains according to the maps prepared by the Federal Emergency Management Agency. TSUNAMIS: Tsunamis are great sea waves produced by submarine earthquakes or volcanic eruptions. Due to the site's location, the site will not be affected by a tsunami. SEICHES: Seiches are periodic oscillations in large bodies of water such as lakes, harbors, bays or reservoirs. Due to the site's location, it will not be affected by Seiches. CONCLUSIONS 1 In general, no geotechnical conditions were encountered that would preclude the construction of the proposed new residence and improvements, provided the recommendations contained in this report are followed. The western portion of the existing building pad is underlain by loose to medium dense fill material. The rest of the lot is underlain by dense terrace deposits capped with a relatively thin layer of topsoil. The fill material and topsoil are not considered to be suitable to support settlement - sensitive structures and improvements in their present condition, and will need to be removed and replaced as compacted structural fill. In addition, we expect that a cut /fill transition line will cross the central portion of the new building pad. In order to provide uniform support for the structure, the cut portion of the building pad will also need to be undercut and the excavated soils replaced as compacted structural fill. Specific site preparation and foundation recommendations are presented in the following section of this report. RECOMMENDATIONS GRADING AND EARTHWORK GENERAL: All grading should conform with the guidelines presented in Appendix Chapter A33 of the Uniform Building Code, the minimum requirements of the City of Encinitas, and the Recommended Grading CWE 200.563.1 October 26, 2000 Page No. 7 Specifications and Special Provisions attached hereto, except where specifically superseded in the text of this report. Prior to grading, a representative of Christian Wheeler Engineering should be present at the preconstruction meeting to provide additional grading guidelines, if necessary, and to review the earthwork schedule. OBSERVATION OF GRADING: Continuous observation by Christian Wheeler Engineering is essential during the grading operation to construct the building pad in order to confirm the conditions anticipated by our investigation, to allow adjustments in design criteria to reflect the actual field conditions exposed, and to determine that the grading proceeds in general accordance with the recommendations contained herein. CLEARING AND GRUBBING: Site preparation should begin with the demolition of the existing structures and the removal of all vegetation, concrete, and other deleterious materials and hard construction debris from the portion of lot that will be graded and that will receive improvements. This should include all root balls from the trees to be removed and all significant root material. The resulting materials should be disposed of off -site. SITE PREPARATION: After clearing and grubbing, site preparation should begin the removal from areas to receive fill and /or settlement - sensitive improvements of the existing fill and topsoils. The existing fill and topsoil should be removed to the contact with competent underlying formational material. We expect that the maximum depth of removal will be on the order of about five feet. However, it should be realized that localized deeper areas may be encountered. In addition, site preparation should include mitigation for the I cut /fill transition that traverses the building pad as discussed in the following section. The bottom of the removal area should be observed and approved by a member of our staff prior to the placement of fill in order to verify that additional removal is not necessary. The on -site soils are considered suitable for use as structural fill. Prior to replacing the excavated soils, the soils exposed at the bottom of the excavation should be processed in accordance with the following section of this report. The soil should be placed in the excavation in accordance with the "Compaction and Method of Filling" section of this report, which follows ' hereinafter. At this time, it is our opinion that no other site preparation will be necessary other than processing the areas to receive fill material as recommended in the following section. CUT /FILL TRANSITION: Where the building pad will be traversed by a cut /fill transition line, the cut portion of the building pad should be undercut at least three feet. The undercut portion should be extended horizontally at least five feet outside the perimeter of the foundations for the proposed structure. The bottom of the overexcavated areas should be sloped in such a manner that water does not become trapped in the �j overexcavated zone. Prior to replacing the excavated materials, the soils exposed at the bottom of the C%VE 200.563.1 October 26, 2000 Page No. 8 excavation should be scarified to depth of six inches, moisture conditioned and compacted to at least 90 percent relative compaction. PROCESSING OF FILL AREAS: Prior to placing any fill soils or constructing any new improvements in areas that have been cleaned out to receive fill, the exposed soils should be scarified to a depth of 12 inches, moisture conditioned, and compacted to at least 90 percent relative compaction. In areas to support fill slopes, keys should be cut into the competent supporting materials. The keys should be at least ten feet wide and be sloped back into the hillside at least two-percent. The keys should extend at least one foot into the competent supporting materials. No other special ground preparation is anticipated at this time. COMPACTION AND METHOD OF FILLING: All structural fill placed at the site should be compacted to a relative compaction of at least 90 percent of maximum dry density as determined by ASTM Laboratory Test D1557 -91. Fills should be placed at or slightly above optimum moisture content, in lifts six to eight inches thick, with each lift compacted by mechanical means. Fills should consist of approved earth material, free of trash or debris, roots, vegetation, or other materials determined to be unsuitable by our soil technicians or project geologist. Fill material should be free of rocks or lumps of soil in excess of twelve inches in maximum dimension. However, in the upper two feet of pad grade, no rocks or lumps of soil in excess of six inches 1 should be allowed. Fills should be benched into all temporary slopes and into competent natural soils when the natural slope is steeper than an inclination of 5:1 (horizontal to vertical). Keys should be constructed at the toe of all fill slopes as recommended above. Utility trench back within five feet of the proposed structures and beneath all pavements and concrete flatwork should be compacted to a minimum of 90 percent of its maximum dry density. 1 FILL SLOPE CONSTRUCTION: Fill slopes may be constructed at an inclination of 2:1 or flatter (horizontal to vertical). Compaction of slopes should be performed by back - rolling with a sheepsfoot compactor at vertical intervals of four feet or less as the fill is being placed, and track - walking the face of the slope when the slope is completed. As an alternative, the fill slopes may be overfilled by at least three feet and then cut back to the compacted core at the design line and grade. Keys should be made at the toe of fill slopes in accordance with the recommendations presented above under "Compaction and Method of Filling." ' IMPORTED FILL MATERIAL• It appears that some amount of fill material will need to be imported to grade the site to receive the proposed improvements. Any imported fill material should be evaluated and 1 approved by the Geotechnical Consultant prior to being imported. At least two working days notice of a C`VE 200.563.1 October 26, 2000 Page No. 9 r potential import source should be given to the Geotechnical Consultant so that appropriate testing can be accomplished. The type of material considered most desirable for import is a nondetrimentally expansive ' granular material with some silt or clay binder. ' SURFACE DRAINAGE: Pad drainage should be designed to collect and direct surface water away from proposed structures and toward approved drainage areas. In general, we recommend that the ground adjacent to structures slope away at a gradient of at least two percent. Densely vegetated areas where runoff can be impaired should have a minim gradient of at least five percent within the first five feet from the structure. GRADING PLAN REVIEW: The final grading plans should be submitted to this office for review in order to ascertain that the recommendations of this report have been implemented, and that no additional recommendations are needed due to changes in the anticipated development plans. FOUNDATIONS GENERAL: Based on our investigation, it is our opinion that proposed single - family residence may be supported by conventional shallow spread footings. New spread footings supporting the proposed two -story structure should be embedded at least 18 inches below finish pad grade. Continuous footings should have a minimum width of 12 inches. Isolated spread footings should have a minim width of 24 inches. BEARING CAPACITY: New conventional spread footings with the above minimum dimensions may be ' designed for an allowable soil bearing pressure of 2,000 pounds per square foot. This value may be increased by one -third for combinations of temporary loads such as those due to wind or seismic loads. FOOTING REINFORCEMENT: The project structural engineer should provide reinforcement requirements for foundations. However, based on soil conditions, we recommend that the minim reinforcing for continuous footings consist of at least one No. 5 bar positioned three inches above the bottom of the footing and one No. 5 bar positioned two inches below the top of the footing. LATERAL LOAD RESISTANCE: Lateral loads against foundations may be resisted by friction between the bottom of the footing and the supporting soil, and by the passive pressure against the footing. The coefficient of friction between concrete and soil may be considered to be and 0.35. The passive resistance may be considered to be equal to an equivalent fluid weight of 350 pounds per cubic foot This assumes the footings are poured tight against undisturbed soil. If a combination of the passive pressure and friction is used, the friction value should be reduced by one - third. CWE 200.563.1 October 26, 2000 Page No. 10 ' SETTLEMENT CHARACTERISTICS: The anticipated total and /or differential settlement is expected to be less than about one -half inch for new foundations, provided the recommendations presented in this report are followed. It should be recognized that minor cracks normally occur in concrete slabs and foundations due to shrinkage during curing or redistribution of stresses, therefore some cracks may be ' anticipated. Such cracks are not necessarily an indication of excessive vertical movements. EXPANSIVE CHARACTERISTICS: The foundation soils were found to have a low expansive potential. The recommendations presented in this report reflect this condition. ' FOUNDATION PLAN REVIEW: The foundation plans should be submitted to this office for review in order to ascertain that the recommendations of this report have been implemented, and that no additional recommendations are needed due to changes in the anticipated construction. FOUNDATION EXCAVATION OBSERVATION: All excavations for new foundations should be observed by the Christian Wheeler Engineering prior to placing concrete to determine if the foundation ' recommendations presented herein are followed. All footing excavations should be excavated neat, level, and square. All loose or unsuitable material should be removed prior to the placement of concrete. ON -GRADE SLABS INTERIOR FLOOR SLAB: It is our opinion that the minim floor slab thickness should be four inches. The floor slab should be reinforced with at least No. 3 bars placed at 18 inches on center each way. The slab reinforcing bars should extend at least six inches into the perimeter footings. Slab reinforcing should be supported by chairs and be positioned at mid - height in the floor slab. MOISTURE PROTECTION FOR INTERIOR SLABS: Where the concrete on -grade floor slabs will support moisture - sensitive floor covering, it should be underlain by a moisture barrier. We recommend that the minim configuration of the subslab moisture barrier consist of a four - inch -thick blanket of coarse, clean sand. The moisture barrier material should have less than ten percent and five percent passing the No. 100 and No. 200 sieves, respectively. A visqueen vapor barrier should be placed in the center of the moisture protection blanket. Our experience indicates that this moisture barrier should allow the transmission of from about six to twelve pounds of moisture per 1000 square feet per day through the on -grade slab. This may be ' an excess amount of moisture for some types of floor covering. If additional protection is considered necessary, additional recommendations can be provided. CWE 200.563.1 October 26, 2000 Page No. 11 ' EXTERIOR CONCRETE FLATWORK Exterior slabs should have a minimum thickness of four inches. Reinforcement and control joints should be constructed in exterior concrete flatwork to reduce the potential for cracking and movement. Joints should be placed in exterior concrete flatwork to help control the location of shrinkage cracks. Spacing of control joints should be in accordance with the American Concrete Institute ' specifications. When patio, walks and porch slabs abut perimeter foundations they should be doweled into the footings. EARTH RETAINING WALLS ' FOUNDATIONS: The recommendations provided in the "Foundations" section of this report are also ' applicable to retaining walls. PASSIVE PRESSURE: The passive pressure for the prevailing soil conditions may be considered to be 350 ' pounds per square foot per foot of depth. This pressure may be increased one -third for seismic loading. The coefficient of friction for concrete to soil may be assumed to be 0.35 for the resistance to lateral movement. When combining frictional and passive resistance, the friction should be reduced by one - third. The upper 12 inches of exterior retaining wall footings should not be included in passive pressure calculations where ' abutted by landscaped or unpaved areas. ' EQUIVALENT FLUID PRESSURES: The active soil pressure for the design of unrestrained earth retaining structures with level backfill may be assumed to be equivalent to the pressure of a fluid weighing 35 ' pounds per cubic foot. This pressure does not consider any surcharge. If any are anticipated, this office should be contacted for the necessary increase in soil pressure. These values assume a drained backfill condition. WATERPROOFING AND SUBDRAIN OBSERVATION: The project architect should provide waterproofing details. The geotechnical engineer should be requested to verify that waterproofing has been properly applied, however, this will not be done unless specifically asked to do so. Also, a suggested wall ' subdrain detail is provided on the attached Plate Number 6. We recommend that the Geotechnical Consultant be retained to observe all retaining wall subdrains to verify proper construction. BACKFILL: All backfill soils should be compacted to at least 90 percent relative compaction. It is anticipated ' that the on -site soils are suitable for use a backfill material, however, any expansive or clayey soils should not be used for backfill material. The wall should not be back-filled until the masonry has reached an adequate strength. ' CWE 200.563.1 October 26, 2000 Page No. 12 LIMITATIONS ' REVIEW, OBSERVATION AND TESTING ' The recommendations presented in this report are contingent upon our review of final plans and specifications. Such plans and specifications should be made available to the geotechnical engineer and engineering geologist so that they may review and verify their compliance with this report and with the Uniform Building Code. It is recommended that Christian Wheeler Engineering be retained to provide continuous soil engineering services during the earthwork operations. This is to verify compliance with the design concepts, specifications or recommendations and to allow design changes in the event that subsurface conditions differ from those anticipated prior to start of construction. UNIFORMITY OF CONDITIONS The recommendations and opinions expressed in this report reflect our best estimate of the project requirements based on an evaluation of the subsurface soil conditions encountered at the subsurface exploration locations and on the assumption that the soil conditions do not deviate appreciably from those encountered. It should be recognized that the performance of the foundations and /or cut and fill slopes may be influenced by undisclosed or unforeseen variations in the soil conditions that may occur in the intermediate and unexplored areas. Any unusual conditions not covered in this report that may be encountered during site development should be brought to the attention of the geotechnical engineer so that ' he may make modifications if necessary. ' CHANGE IN SCOPE This office should be advised of any changes in the project scope or proposed site grading so that we may determine if the recommendations contained herein are appropriate. This should be verified in writing or modified by a written addendum. TIME LIMITATIONS The findings of this report are valid as of this date. Changes in the condition of a property can, however, ' occur with the passage of time, whether they be due to natural processes or the work of man on this or adjacent properties. In addition, changes in the Standards -of- Practice and /or Government Codes may occur. 1 ' CWE 200.563.1 October 26, 2000 Page No. 13 Due to such changes, the findings of this report may be invalidated wholly or in part by changes beyond our control. Therefore, this report should not be relied upon after a period of two years without a review by us ' verifying the suitability of the conclusions and recommendations. PROFESSIONAL STANDARD ' In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. The client recognizes that subsurface conditions may vary from those encountered at the locations where our test pits, surveys, and explorations are made, and that our data, interpretations, and recommendations be based solely on the information obtained by us. We will be responsible for those data, interpretations, and ' recommendations, but shall not be responsible for the interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. CLIENT'S RESPONSIBILITY It is the responsibility of the client, or their representatives, to ensure that the information and recommendations contained herein are brought to the attention of the structural engineer and architect for the project and incorporated into the project's plans and specifications. It is further their responsibility to take the necessary measures to insure that the contractor and his subcontractors carry out such ' recommendations during construction. FIELD EXPLORATIONS Four subsurface explorations were made at the locations indicated on the site plan included herewith as Plate Number 1 on October 5, 2000. These explorations consisted of manually excavated test pits. The fieldwork was conducted by or under the observation of our engineering geology personnel. The explorations were carefully logged when made. The test pit logs are presented on the following Plate Numbers 2 through 5. The soils are described in accordance with the Unified Soils Classification. In addition, a verbal textural description, the wet color, the apparent moisture and the density or consistency are provided. The density of granular soils is given as either very loose, loose, medium dense, dense or very dense. The consistency of silts or clays is given as either very soft, soft, medium stiff, stiff, very stiff, or hard. CWE 200.563.1 October 26, 2000 Page No. 14 Bulk samples of disturbed soil were collected in bags from the pit excavation. In addition, "undisturbed" samples of representative soils were obtained from the borings and returned to the laboratory for testing. The ' undisturbed samples from the borings were obtained by driving a 2 -3/8 inch ID split -tube sampler ahead of the auger using a 140 -pound weight free falling a distance of 30 inches. The number of blows to drive the 1 sampler twelve inches was recorded and this number is presented on the boring logs as the "Penetration Resistance ". LABORATORY TESTING Laborato ry tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. A brief description of the tests performed is i presented below: a) CLASSIFICATION: Field classifications were verified in the laboratory by visual examination. The final soil classifications are in accordance with the Unified Soil Classification System. b) MOISTURE - DENSITY: In -place moisture contents and dry densities were determined for representative soil samples. This information was an aid to classification and permitted recognition of variations in material consistency with depth. The dry unit weight is determined in pounds per cubic foot, and the in -place moisture content is determined as a percentage of the soil's dry weight. The results of these tests are summarized in the test pit logs. ' c COMPACTION TEST: The maximum dry density and optimum moisture content of a typical soil were determined in the laboratory in accordance with ASTM Standard Test D- 1557 -91. The results of this test are presented on Plate Number 7. ' d) DIRECT SHEAR TEST: Direct shear tests were performed to determine the failure envelope based on yield shear strength. The shear box was designed to accommodate a sample having a ' diameter of 2.375 inches or 2.50 inches and a height of 1.0 inch. Samples were saturated and tested at different vertical loads. The shear stress was applied at a constant rate of strain of approximately 0.05 ' inch per minute. The results of these tests are presented on the attached Plate Number 7. ' e) GRAIN SIZE DISTRIBUTION: The grain size distribution was determined from representative samples of the topsoil and Bay Point Formation in accordance with ASTM D422. The results of ' these tests are presented on Plate Number 7. LOG OF TEST PIT NUMBER P -1 Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC ' Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A ' SAMPLES v W o N O ✓✓ C) C SUMMARY OF SUBSURFACE CONDITIONS N Q W W O E_ Q ° 0 Q a 1 � 1 Terrace Deposits (Qt): Reddish- brown, SILTY SAND (SM), humid, dense. CK 3.7 108.9 SA 1 CK MD CK 6.0 111.2 DS 2 cK Material becomes moist. CK 8.6 1126 3 ' 4 Test pit terminated at 3 feet. 5 6 7 1 8 9 10 ' PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hyrnettus Avenue, Encinitas, California ' CHRISTIAN WHEELER BY: SCC DATE: 10/26/00 ENGINEERING JOB NO.: 200.563 1PLATE NO.: 2 1 LOG OF TEST PIT NUMBER P -2 ' Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A 1 SAMPLES C7 O 1 v SUMMARY OF SUBSURFACE CONDITIONS a s Q Z U 0 H Q � � 0 C7 1 Terrace Deposits (Otl: Reddish- brown, SILTY SAND (SK, moist, dense, medium to coarse - grained. CK 4.7 113.2 1 �- CK CK 4.7 107.9 2 ,,, s,. CK ., CK 4.7 119.8 3 4 Test pit terminated at 3 feet. 5 l 6 8 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hymettus Avenue, Encinitas, California CHRISTIAN WHEELER BY: SCC DATE: 10/26/00 ENGINEERING JOB NO.: 200.563 PLATE NO.: 3 LOG OF TEST PIT NUMBER P -3 ' Date Excavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A 1 SAMPLES a O W W 0 O 1 x SUMMARY OF SUBSURFACE CONDITIONS a Q z W w w — O H O Fill : Medium brown, SILTY SAND (SM), moist, loose. r, CK 1 1 � � CK em r 2 ............................................................................................................... ............................... CK ......... ....... ......... ........ Grayish -brown to reddish- brown, CLAYEY SAND (SC), moist CK ' medium dense. CK 3 Tovsoil: Brown, SANDY CLAY (SC), moist, loose. us 1 Terrace Deposits (Ot): Reddish - brown, SILTY SAND (SIVI), moist CK 9.8 115.6 dense, medium- to coarse grained 5 6 Test pit terminated at 4' /2 feet. 7 8 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hymettus Avenue, Encinitas, California CHRISTIAN WHEELER BY: SCC DATE: 10/26/00 ENGINEERING JOB NO.: 200.563 1 PLATE NO.: 4 LOG OF TEST PIT NUMBER P -4 =DateExcavated: 10/5/00 Logged by: JAB Equipment: Hand Tools Project Manager: CHC Surface Elevation (ft): 155 MSL Depth to Water:: N/A Hammer Weight: N/A Drop of Hammer: N/A ' SAMPLES C� O W W ZZ a wW SUMMARY OF SUBSURFACE CONDITIONS a M � Q O ~ O Q 1 ' Fill : Reddish- brown, SILTY SAND (Siva), moist, loose. F M CK 2 Terrace Deposits (Qo: Reddish- brown, SILTY SAND (Siva), moist, dense, medium to coarse - grained CK 5.8 106.7 3 4 Test pit terminated at 3 feet. 5 1 6 7 8 I 9 10 PROPOSED SINGLE - FAMILY RESIDENCE 1024 Hymettus Avenue, Encinitas, California CHRIST]AN WHEELER BY: SCC DATE: 10/26/00 ENGINEERING JOB NO.: 200.563 PLATE NO.: 5 I � I ' +-�% SLOPE MINIMUM _ _ 6" MIN 6" MAX WATERPROOF BACK OF WALL s ° PER ARCHITECT'S SPECIFICATIONS e 3/4 1•146H CRtJSHED ROCK or MIRADRAIN 6000 or EQUIVALENT ° • °.. GEOFABRIC BETWEEN ROCK AND SOIL 12i s c TOP OF GROUND 0 or CONCRETE SLAB •' o 6" MIN i MINIMUM 4 INCH DIAMETER PERFORATED PIPE RETAINING WALL SUBDRAIN DETAIL No Scale Christian Wheeler Engineering Job Number: 200.563.1 Date: OCTOBER 26, 2000 Plate Number: 6 LABORATORY TEST RESULTS PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYMETI'US AVENUE ENCINITAS. CALIFORNIA t DIRECT SHEAR TEST Sample Number Test Pit P -1 @ 1 /2' -3' Description Remolded to 90 % Angle of Internal Friction 32 degrees Apparent Cohesion 300 psf COMPACTION TEST Sample Number: Test Pit P -1 @' /z' -3' Sample Description: Reddish- Brown, Silty Sand (SM) ' Optimum Moisture: 8.1 percent Maximum Density: 131.8 pcf GRAIN SIZE DISTRIBUTION Sample Number Test Pit P -1 @'/z' -3' Sieve Size Percent Passing #4 #g 100 #16 99 #30 92 #50 52 #100 29 #200 29 Classification SM C`VE 200.563 October 26, 2000 Plate No. 7 CWE 200.563 October 26, 2000 Appendix A, Page A -1 REFERENCES Anderson, J.G.; Rockwell, R.K. and Agnew, D.C., 1989, Past and Possible Future Earthquakes of Significance to the San Diego Region, Earthquake Spectra Volume 5, No. 2, 1989. California Division of Mines and Geology, 1998, Maps of Known Active Fault Near Source -Zones in California and Adjacent Portions of Nevada. Jennings, C -W, 1975, Fault Map of California, California Division of Mines and Geology, Map No. 1, Scale 1:750,000. Kern, P., 1989, Earthquakes and Faults in San Diego County, Pickle Press, 73 pp. Mualchin, L. and Jones, A.L., 1992, Peak Acceleration from Maximum Credible Earthquakes in California (Rock and Stiff -Soil Sites) California Division of Mines and Geology Open -File Report 92 -1. `Vesnousky, S.G., 1986, "Earthquakes, Quaternary Faults, and Seismic Hazards in California ", in Journal of Geophysical Research, Volume 91, No. B12, pp 12,587 to 12,631, November 1986. TOPOGRAPHIC MAPS County of San Diego, 1979, Map Sheet 326 -1677; Scale: 1 inch = 200 feet U.S. Geological Survey, 1968 (Photo- revised 1975), 7' /2 Minute Topographic Map, Encinitas, CA Quadrangle, scale 1:24,000. r C``UE 200.563.1 October 26, 2000 Appendix B, Page B -1 RECOMMENDED GRADING SPECIFICATIONS - GENERAL PROVISIONS PROPOSED SINGLE - FAMILY RESIDENCE 1024 HYIAETTUS AVENUE ENCINITAS CALIFORNIA GENERAL INTENT The intent of these specifications is to establish procedures for clearing, compacting natural ground, preparing areas to be filled, and placing and compacting fill soils to the lines and grades shown on the accepted plans. The recommendations contained in the preliminary geotechnical investigation report and /or the attached Special Provisions are a part of the Recommended Grading Specifications and shall supersede the provisions contained hereinafter in the case of conflict. These specifications shall only be used in conjunction with the geotechnical report for which they are a part. No deviation from these specifications will be allowed, except where specified in the geotechnical report or in other written communication signed by the Geotechnical Engineer. OBSERVATION AND TESTING Christian Wheeler Engineering shall be retained as the Geotechnical Engineer to observe and test the earthwork in accordance with these specifications. It will be necessary that the Geotechnical Engineer or his representative provide adequate observation so that he may provide his opinion as to whether or not the work was accomplished as specified. It shall be the responsibility of the contractor to assist the Geotechnical Engineer and to keep him appraised of work schedules, changes and new information and data so that he j may provide these opinions. In the event that any unusual conditions not covered by the special provisions or preliminary geotechnical report are encountered during the grading operations, the Geotechnical Engineer shall be contacted for further recommendations. If, in the opinion of the Geotechnical Engineer, substandard conditions are encountered, such as questionable or unsuitable soil, unacceptable moisture content, inadequate compaction, adverse weather, etc., construction should be stopped until the conditions are remedied or corrected or he shall recommend rejection of this work. Tests used to determine the degree of compaction should be performed in accordance with the following American Society for Testing and Materials test methods: C%VE 200.563.1 October 26, 2000 Appendix B, Page B -2 Maximum Density & Optimum Moisture Content - ASTM D- 1557 -91 Density of Soil In -Place - ASTM D- 1556 -90 or ASTM D -2922 All densities shall be expressed in terms of Relative Compaction as determined by the foregoing ASTM testing procedures. PREPARATION OF AREAS TO RECEIVE FILL All vegetation, brush and debris derived from clearing operations shall be removed, and legally disposed of All areas disturbed by site grading should be left in a neat and finished appearance, free from unsightly debris. After clearing or benching the natural ground, the areas to be filled shall be scarified to a depth of 6 inches, brought to the proper moisture content, compacted and tested for the specified minim degree of compaction. All loose soils in excess of 6 inches thick should be removed to firm natural ground which is ' defined as natural soil which possesses an in -situ density of at least 90 percent of its maximum densi �Y t3. ' When the slope of the natural ground receiving fill exceeds 20 percent (5 horizontal units to 1 vertical unit), the original ground shall be stepped or benched. Benches shall be cut to a firm competent formational soil. The lower bench shall be at least 10 feet wide or 1 -1/2 times the equipment width, whichever is greater, and shall be sloped back into the hillside at a gradient of not less than two (2) percent. All other benches should be at least 6 feet wide. The horizontal portion of each bench shall be compacted prior to receiving fill as specified herein for compacted natural ground. Ground slopes flatter than 20 percent shall be benched when considered necessary by the Geotechnical Engineer. Any abandoned buried structures encountered during grading operations must be totally removed. All underground utilities to be abandoned beneath any proposed structure should be removed from within 10 feet of the structure and properly capped off. The resulting depressions from the above described procedure should be backfilled with acceptable soil that is compacted to the requirements of the Geotechnical Engineer. l This includes, but is not limited to, septic tanks, fuel tanks, sewer lines or leach lines, storm drains and water lines. Any buried structures or utilities not to be abandoned should be brought to the attention of the Geotechnical Engineer so that he may determine if any special recommendation will be necessary. All water wells which will be abandoned should be backfilled and capped in accordance to the requirements set forth by the Geotechnical Engineer. The top of the cap should be at least 4 feet below finish grade or 3 I C``UE 200.56 3.1 3 1 October 26, 2000 Appendix B, Page B -3 feet below the bottom of footing hichever is e g greater. The type of cap will depend on the diameter of the well and should be determined by the Geotechnical Engineer and /or a qualified Structural Engineer. FILL MATERIAL Materials to be placed in the fill shall be approved by the Geotechnical Engineer and shall be free of ' vegetable matter and other deleterious substances. Granular soil shall contain sufficient fine material to fill the voids. The definition and disposition of oversized rocks and expansive or detrimental soils are covered in the geotechnical report or Special Provisions. Expansive soils, soils of poor gradation, or soils with low strength characteristics may be thoroughly mixed with other soils to provide satisfactory fill material, but only with the explicit consent of the Geotechnical Engineer. Any import material shall be approved by the Geotechnical Engineer before being brought to the site. PLACING AND COMPACTION OF FILL Approved fill material shall be placed in areas re ared to receive P P fill in layers not to exceed 6 inches in compacted thickness. Each layer shall have a uniform moisture content in the range that will allow the compaction effort to be efficiently applied to achieve the specified degree of compaction. Each layer shall be uniformly compacted to the specified minimum degree of compaction with equipment of adequate size to economically compact the layer. Compaction equipment should either be specifically designed for soil compaction or of proven reliability. The minimum degree of compaction to be achieved is specified in either the Special Provisions or the recommendations contained in the preliminary geotechnical investigation report. When the structural fill material includes rocks, no rocks will be allowed to nest and all voids must be carefully filled with soil such that the minimum degree of compaction recommended in the Special Provisions is achieved. The maximum size and spacing of rock permitted in structural fills and in non- structural fills is discussed in the geotechnical report, when applicable. Field observation and compaction tests to estimate the degree of compaction of the fill will be taken by the Geotechnical Engineer or his representative. The location and frequency of the tests shall be at the Geotechnical Engineer's discretion. When the compaction test indicates that a particular layer is at less than the required degree of compaction, the layer shall be reworked to the satisfaction of the Geotechnical Engineer and until the desired relative compaction has been obtained. C%VE 200.563.1 October 26, 2000 Appendix B, Page B -4 Fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction by sheepsfoot roller shall be at vertical intervals of not greater than four feet. In addition, fill slopes at a ratio of r two horizontal to one vertical or flatter, should be trackrolled. Steeper fill slopes shall be over -built and cut- back to finish contours after the slope has been constructed. Slope compaction operations shall result in all fill material six or more inches inward from the finished face of the slope having a relative compaction of at least 90 percent of maximum dry density or the degree of compaction specified in the Special Provisions ' section of this specification. The compaction operation on the slopes shall be continued until the Geotechnical Engineer is of the opinion that the slopes will be surficially stable. Density tests in the slopes will be made by the Geotechnical Engineer during construction of the slopes to determine if the required compaction is being achieved. Where failing tests occur or other field problems arise, the Contractor will be notified that day of such conditions by written communication from the Geotechnical Engineer or his representative in the form of a daily field report. If the method of achieving the required slope compaction selected by the Contractor fails to produce the necessary results, the Contractor shall rework or rebuild such slopes until the required degree of compaction is obtained, at no cost to the Owner or Geotechnical Engineer. CUT SLOPES The Engineering Geologist shall inspect cut slopes excavated in rock or lithified formational material during the grading operations at intervals determined at his discretion. If any conditions not anticipated in the preliminary report such as perched water, seepage, lenticular or confined strata of a potentially adverse nature, unfavorably inclined bedding, joints or fault planes are encountered during grading, these conditions shall be analyzed by the Engineering Geologist and Geotechnical Engineer to determine if mitigating measures are necessary. Unless otherwise specified in the geotechnical report, no cut slopes shall be excavated higher or steeper than that allowed by the ordinances of the controlling governmental agency. ENGINEERING OBSERVATION Field observation by the Geotechnical Engineer or his representative shall be made during the filling and compaction operations so that he can express his opinion regarding the conformance of the grading with acceptable standards of practice. Neither the presence of the Geotechnical Engineer or his representative or CWE 200.563.1 October 26, 2000 Appendix B, Page B -5 the observation and testing hall release the g Grading Contractor from his duty to compact all Fill material to the specified degree of compaction. SEASON LIMITS Fill shall not be placed during unfavorable weather conditions. When work is interrupted by heavy rain, filling operations shall not be resumed until the proper moisture content and density of the fill materials can be achieved. Damaged site conditions resulting from weather or acts of God shall be repaired before acceptance of work. RECOMMENDED GRADING SPECIFICATIONS - SPECIAL PROVISIONS RELATIVE COMPACTION: The minimum degree of compaction to be obtained in compacted natural ground, compacted fill, and compacted backfill shall be at least 90 percent. For street and parking lot subgrade, the upper six inches should be compacted to at least 95 percent relative compaction. EXPANSIVE SOILS: Detrimentally expansive soil is defined as clayey soil which has an expansion index of 50 or greater when tested in accordance with the Uniform Building Code Standard 29 -C. ' OVERSIZED MATERIAL: Oversized fill material is generally defined herein as rocks or lumps of soil over 6 inches in diameter. Oversized materials should not be placed in fill unless recommendations of placement of such material is provided by the Geotechnical Engineer. At least 40 percent of the fill soils shall pass through a No. 4 U.S. Standard Sieve. TRANSITION LOTS: Where transitions between cut and fill occur within the proposed building pad, the cut portion should be undercut a minimum of one foot below the base of the proposed footings and recompacted as structural backfill. In certain cases that would be addressed in the geotechnical report, special footing reinforcement or a combination of special footing reinforcement and undercutting may be required. T A I T Consulting, Inc. ENGINEERINGSERVICES 717 Pier View Way CIT Y0 ENCINITAS Oceanside, CA 92054 —^ Phone 760 433 -1166 Fax 760 433 -1017 TURNER RESIDENCE DATE: 24 MAY 2001 ADDRESS: 1024 HYMETTIUS AVENUE, ENCINITAS, CA, 92024 APN #: 2,W3344 21� DRAINAGE ANALYSIS THE EXISTING DWELLING IS TO BE DEMOLISHED AND MINOR GRADING WILL BE DONE FOR THE NEW DRIVEWAY, BEFORE THE CONSTRUCTION OF A NEW DWELLING. THERE IS NO INGRESS OF STORMWATER FROM OFFSITE SOURCES. THE DRAINAGE PATTERN FOR THE PROPOSED GRADING, HAS NOT ALTERED FROM THE EXISTING. THE FLOW FROM THE ROOF WILL BE COLLECTED, AND TEMPORARILY STORED IN AN UNDERGROUND TANK WHICH WILL BE USED FOR GARDEN IRRIGATION. THEREFORE, THE FLOW FROM THE PROPOSED DEVELOPED SITE, WILL NOT EXCEED THE FLOW FROM THE EXISTING DEVELOPED SITUATION. Q RV E SSI O E A. r� w �- No. 32247. 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