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HomeMy WebLinkAboutCT 11-02; LA COSTA VISTA; SOILS; 2011-02-19liECOR,!.! COPY h'hlnl •""•tr7~^14-5E1-5611 '"/ill nil- — _ „ , . ZC •z< 'S E O C O N B U L T ANTS —fT»iX-y44^1-25S2 7372 Walnut Avenue, Unit F.Buena Park, Catiforrtfa 90620 February 19,2011 Rev.eaOcto.„4,20n RECEIVED^" FEB 112013 TonySfredo LAND DEVELOPMENT L"^, 92603 ENGINEERING Subject: Geotechnical Engineering Investigation of Proposed Multi Family Residential Development,| ; Court, Carlsbad, Califomia. Gentlemen; Pursuant to your request, a geotechnical investigation has been performed at the subject site. The purposes of the investigation were to determine the general engineering characteristics of the soils on and underlying the site and to provide recommendations for the design of foundations, pavements and linderground improvements. PROPOSED DEVELOPMENT It is our understanding that the proposed development will consist of approximately 7 attached town homes of wood-framed construction with parking and landscaping. PURPOSE AND SCOPE OF SERVICES The scope of the study was to obtain subsurface information within the project site area and to provide recomniendations pertaining to the proposed development and included the following: 1. A cursory reicormaissance of the site and surrounding areas. i 2. Excavation jof exploratory geoteclmical test pits to determine the subsurface soil and groundwater, conditions. 3. Collection of representative bulk and/or undisturbed soil samples for laboratory analysis. 4. Laboratory analyses of soil samples including determination of in-situ and maximum density, in-situ and optimum moisture content, shear strength and consohdation characteristics, expansion potential and liquefaction analysis. 5. Preparation of this report presenting results of our investigation and recommendations for the proposed de'Velopment. 1 STRATA-TEG H,l N C. BEDCONSUl-TANTS TonySfredo 2 W.O. 263810 Geotechnical Engineering Investigation October 4,2011 SITE CONDITIONS The 115 by 150 foot rectangular lot is located on the westem side of the Jerez Court Cul de sac. The site is shown on the attached vicinity Map, Plate No. 1. Two story wood frame dwellings exist both north and south ofthe site. A golf course exists on grade adjacent to the westem property line It is our understanding that the new homes will be set back at least 5-feet from the property line. Site configuration is further illustrated on the Site Plan, Plate 2. FIELD INVESTIGATION The field investigation was performed on January 19, 2011, consisting of excavating two backhoe test pits. The locations are shown on the attached Site Plan, Plate 2. As the excavation progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing. Test Pit #2 was extended to 10-feet to confmn the lack of groundwater at 10-feet. Description of the soils encountered are presented on the attached Test Pit Logs. The data presented on thise logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring location and the date excavated. It is not warranted to be representative of subsurface conditions at other locations and times. EARTH MATERIALS Earth materials encountered within the exploratory test pits were visually logged by a representative from STRATA-TECH, Inc. The materials were classified as artificial fill and native soils. Native soils consisted of a silty residual sandy soil to a maximum depth explored of 10 feet in test pit 2. Groundwater was not encountered in any of our geotechnical pits. SEISMICITY Southem Califomia is located in an active seismic region. Moderate to sfrong earthquakes can occur on numerous faults. The United States Geological Survey, Califomia Division of Mines and Geology, priv^ite consultants, and universities have been studying earthquakes in Southern CaUfomia for several decades. The purpose ofthe code seismic design parameters is to prevent collapse during sfrong ground shaking. Cosmetic damage should be expected. STRATA-TEG H, I N C, C3EDCONSUI-TANTS TonySfredo 3 W.O, 263810 Geotechnical Engineering Investigation October 4, 2011 The principal seismic hazard to the subject property and proposed project is strong ground shaking from earthquakes produced by local faults. Secondary effects such as surface rapture, lurching, or flooding are not considered probable. SEISMIC DESIGN VALUES NEHRP Seismic Design Provisions Site Class D - Fa = 1.05 ,Fv = 1.57 Spectral Response Accelerations Ss and SI = Mapped Spectral Acceleration Values Data are based on a 0.01 deg grid spacing Ss=Ll4 Si=0.43 Sa=.79 CONCLUSIONS AND RECOMMENDATIONS Development of the site as proposed is considered feasible from a soils engineering standpoint, provided that -fhe recommendations'^Stated herein are incorporated in the design and are implemented in the field. Recommeridations are subject to change based on review of final foundation and grading plans. It is recommended that the proposed stmctures be entfrely supported by compacted fill. A minimum 2-foot thick compacted fill blanket below the bottom of the footings is recommended. The over excavation requirement is 2 foot below footings, or 4 feet deep for 2 foot footings. Ifthe'pad grade is cut, then the bottom will have to be deeper o For other minor structures such as property line walls or retaining walls less than 4 feet high, competent nati\^e soils or compacted fill may be used for stinctural support. ,1 PROPOSED GRADING Grading plans were not available at the time our work was performed. It is assumed that proposed grades will not differ significantly from existing grades. The following recommendatioiis are subject to ciiange based on review of final grading plans. V •V GRADING RECOMMENDATIONS Removal and recompaction of existing fill and loose native soils will be required to provide adequate support for foundations and slabs on grade. The depth of removal shall be 1 foot below the bottom of the footings, which is estimated to be at least 3 feet below existing grade. The over excavation requirement is 1 foot below footings, or 3 feet deep for 2 foot footings. If the pad grade is cut^ then the bottom will have to be deeper STRATA -TEICH, iNC GEOCDNSyi-TANTS Tony Sfredo Geotechnical Engineering Investigation W. O. 263810 October 4. 2011 Earthwork for foundation support shall mclude the entire building pad and shall extend a minimum of 5 feet outside exterior footing lines where feasible or to property line. Care shall be exercised not to undennine hardscape, walls, or pavements that are located on adjacent properties. If removals extend to off site structures or concrete block perimeter walls that are located within 4-feet from the bottom excavation, then slot cutting or shoring will be required. The exposed excavation bottom shall be observed and approved by STRATA-TECH, Inc. and the City's grading inspector prior to processing. Dependent on field observations, removals may be adjusted up or down. Subsequent to approval of the excavation bottom, the area shall be scarified 6 inches, moisture conditioned as needed, and compacted to a minimum of 90 percent relative compaction. Fill soils shall' be placed in 6 to 8 inch loose lifts, moisture conditioned as needed, and compacted to a minimum of 90 percent relative compaction. This process shall be utilized to finish grade. • , , Grading for hardscape areas shall consist of removal and recompaction of soft surficial soils. Removal depths are estimated at 1 to 2 feet. Earthwork shall be performed in accordance with previously specified methods. Grading and/or foundation plans shall be reviewed by the soil engineer. All recommendations are subject to modification upon review of such plans. FOUNDATIONS ON COMPACTED FILL The proposed building may be supported by continuous spread and isolated footings placed a minimum depth'of 24 inches below lowest adjacent grade utilizing an allowable bearing value of 2,000 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. Minimum • Depth Minimum Width • (inches)''. Bearing Value Maximum (psO Minimum • Depth Minimum Width • (inches)''. Bearing Value :;.i-:i^Widii::l^^i:--Depth Maximum (psO Minimum • Depth Minimum Width • (inches)''. Bearing Value (J5sf/fl) Maximum (psO Continuous • 24 ' 12 2000 180 440 3500 Interior Pad 18 24 2000 ISO 440 3500 It is recommended that all footings be reinforced with a minimum of two no. 4 bars (1 top and 1 bottom). The structural engineer's reinforcing requirements should be followed if more stringent. STRATA G E D C O N S - T E C H , I N D tl !_ T A N T S Tony Sfredo Geotechnical Engineering Investigation W. O. 263810 October 4, 2011 Footing excavations shall be observed by a representative of STRATA-TECH, Inc. prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil conditions are exposed mitigation will be recommended. FOUNDATIONS ON COMPETENT NATIVE SOILS - for Minor Structures Minor stractures may be supported by continuous spread footings placed a minimum depth of 24 inches below lowest adjacent grade and 12-inches into natural soil utilizing an allowable bearing value of 1,500 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. •J Footing excavations shall be observed by a representative of STRATA-TECH, Inc. prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil conditions are exposed, mitigation will be recommended. LATERAL DESIGN Lateral restraint'at the base of footings a,nd on slabs may be assumed to be the product of the dead load and a coefficient of fiiction of .30. Passive pressure on the face of footings may also be used to resist lateral forces. A passive pressure of zero at the surface of fmished grade, increasing at the rate of 300 pounds per square fo«)t: of depth to a maximum value of 2,500 pounds per square foot, may be used for compacted fill or native soils at this site. If passive pressure and friction are combined when-evaluating the latercll resistance, the value ofthe passive pressure should be limited to 2/3 of the valties given above. " • ' ' RETAINING WALLS Unrestrained walls up to 5-feet in height retaining drained earth may be designed for the following: , —_____—..... .. .. ... ;„„„„/,T".i, Suirface Slope of Retained Material Horizontal to Vertical Equivalent Fluid Pressui'e Pounds Per Cubic Foot < Level 30 Sto 1 < , 32 4 to 1 35 3 tol 38 2 tol 43 These values mclude seismic loading. 'Backfill should consist of clean sand and gravel. While all backfills should'be compacted to the i-equired degree, exfra care should be taken working close to walls to prevent-excessive pressure. Retauiing walls should include subdrams consisting of 4-inch, SCH 40 or SDR 35 perforated pipe surrounded by 1 cubic foot per lineal foot of crashed rock. All wall backfill should be compacted to a minimum of 90 percent relative compaction. STRATA-TEC H,l N C. QEOCDNSyL,TANTS. . TonySfredo g W.O. 263810 Geotechnical Engineering Investigation October 4. 2011 All retaining stractures should include appropriate allowances for anticipated surcharge loading, where applicable. In this regard, a uniformly distributed horizontal load equal to one-half the vertical surcharge shall be applied when the surcharge is within a horizontal distance equal to the wall height. Retaining wall footing excavations shall be founded entirely in competent native soils or compacted fill. Footing bottoms shall be observed by a representative of STRATA-TECH, Inc., to verify competent conditions. EXPANSIVE SOILS Results of expansion tests uidicate that the near surface soils have a low expansion potential. SETTLEMENT The maximum 'total post-constriictibn- settlement is anticipated to be on the order of 1/2 inch. Differential settlements are expected to be less than 1/2 inch, measured between adjacent stmctural elemerrts. SUBSIDENCE & SHRINKAGE Subsidence over the site during grading is anticipated to be on the order of .5 feet. Shrinkage of reworked materials should be in the range of 10 to 15 percent. FLOOR SLABS 1 The surface soils are non-plastic with low expansion potential. Where concrete slabs on grade are utilized, the slab shall be supported on at least 1 foot of engineered fill lompacted to a minimum of 90 percent relative compaction. Slabs should be at least 4 inches thick and reinforced with a minimum of no. 3 bars 24 inches on center both ways. i:- • The soil should be kept moist prior to casting the slab. However, if the soils at grade become disturbed during constmction, they should be brought to approximately optimum moisture content and rolled to a firm, imyielding condition prior to placing concrete. In areas where a moisture sensitive floor covering will be used, a vapor barrier consisting of a plastic film (6 ml polyvinyl chloride or equivalent) should be used. The vapor barrier should be properly lapped and sealed. Since the vapor barrier will prevent moisture from draining from fresh STRATA-TEG H,l NG, QEOCONSyi-TANTS TonySfredo W.O. 263810 Geotechnical Engineering Investigation October 4. 2011 concrete, a better concrete finish can usually be obtained if at least 2 inches of wet sand is spread over the vapor barrier prior to placement of concrete. UTILITY LINE BACKFILLS All utility line backfills, both interior and exterior, shall be compacted to a minimum of 90 percent relative compaction and shall require testing at a maximum of 2-foot vertical intervals. HARDSCAPE AND SLABS Hardscape and Slab subgrade areas shall exhibit a minimum of 90 percent relative compaction to a depth of at least 1 foot. Deeper removal and recompaction may be requfred if unacceptable conditions are encountered. These areas requfre testing just prior to placing concrete. STORMWATER INFILTRATION TEST RESULTS Two Hand Dug; test pits were excavated at 3-foot elevation in the bottom ofthe back hoe test pits. The diameter ofthe test hole was 6-inches. The lower depth of the pit exposed a natural soil layer of very dense brown sandy silt. The percolation testjwas performed by siphoning a 5-gallon water bottle into the hand-dug hole. The water level wasifkept at 5 to 6 inches in depth for a period of four hours. At the end of four hours, the time for th#, water to drop from the o to the 5* inch was measured. This value was 105 minutes for both holes. The percolation rate can be expected to perform at the tested rate over a short period oftime with clean water flowing into undisturbed soil. A high factor of safety should be used for longer-term use with unfiltered water. The percolation rate can be expected to increase at a power of 1.5 with respect to head increase. DRAINAGE Positive drainagb should be planned for the site. Drainage should be directed away from stmctures via non-erodible conduits to suitable disposal areas. Unlined flowerbeds, planters, arid lawiis should not be constmcted against the perimeter of the stmcture. If siich landscaping (against the perimeter of a stmcture) is planned, it should be properly drained and lined or provided with an underground moisture barrier. Irrigation should be kept to a minimum. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, tb ensure that the information and recommendations contained herein are called to the attention ofthe engineers for the project and incorporated into the plans and that the necessary S T R A T A - T E G H , I N G . GEDCONSUI-TANTS TonySfredo g W.O. 263810 Geotechnical Engineering Investigation October 4. 2011 steps are taken to see that the Contractors and Subcontractors carry out such recommendations in the field. ENGINEERING CONSULTATION, TESTING & OBSERVATION We will be pleased to provide additional input with respect to foundation design once methods of constraction and/or nature of imported soil has been determined. Grading and foundation plans should be reviewed by this office prior to commencement of grading so that appropriate recommendations, if needed, can be made. Areas to receive fill should be hispected when unsuitable materials have been removed and prior to placement of fill, and fill should be observed and tested for compaction as it is placed. AGENCY REVIEW All soil, geologic and sfractural aspects of the proposed development are subject to the review and approval of the goveming agency(s). It should be recognized that the goveming agency (s) can dictate the manner in which the project proceeds. They could approve or deny any aspect of the proposed impro^^ements and/or could 4ictate which foundation and grading options are acceptable. Supplemental geotechnical consulting in response to agency requests for additional information could be requfred and will be charged oii a time and materials basis. LIMITATIONS This report presents recommendations pertaining to the subject site based on the assumption that the subsurface conditions do not deviate appreciably from those disclosed by our exploratory excavations. Our recommendations are based on the technical information, our understanding of the proposed construction, and our experience in the geotechnical field. We do not guarantee the performance ofthe project, only that our engineering work and judgments meet the standard of care of our profession at this time. In view of the general conditions ih' the area, the possibility of different local soil conditions may exist. Any deviation or unexpected coridition observed during constraction should be brought to the attention ofthe Geotechnical Ehgineer. In this way, any supplemental recommendations can be made with a min'imum of delay neiCessary to the project. f If the proposed Constraction will differ from our present understanding of the project, the existing information and possibly new factors may have to be evaluated. Any design changes and the finished plans should be reviewed by the Geotechnical Consultant. Of particular importance would be extending development to new areas, changes in sfractural loading conditions, postponed development for! more than a year, or changes in ownership. I S T R A T A - ,T E G H , I N C GEOCONSLJI-TANTS Tony Sfredo Geotechnical Engineering Investigation W. O. 263810 October 4. 2011 This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the infomiation and recommendations contained herein are called to the attention ofthe Architects and Engineers for the project and incorporated into the plans and that the necessary steps are taken to see that the contractors and subcontractors carry out such recommendations in the field. This report is subject to review by the controlling authorities for this project. We appreciate this opportunity to be of service to you. Roland Acuna Principal Enclosures: Larry ^jMey RCE 46606 Plate 1: yicinity Map Plate 2: Site Plan and Boring Location Map Test Pit Logs Appendix A: Laboratory Resuhs and Engineering Calculations Appendix B: Specifications for Grading VICINITY MAP CE X. o CD n cr rf4 I I t(5 P :• it ft Encinitas."' S11 V Alga Rd UntoT .1 Carlsbad ^4 ...a 7500 JerezCt, Garlsbad, CA. 7500 Jerez Ct Carlsbad, CA 92009 S11. % 'ce- 0 • Levante- St:"- La ••I Copyright i])2Dp5 Mclisoft Cotp. and/or its suppliers. i^i;righls_re£eRfed. JJL. -4: Geotechnical Engineering Investigation 7500 jerez court Carlsbaci Work Order 262310 Geotechnical Engineering Investigation 7500 jerez court Carlsbaci Plate No. 1 STRATA - TECH, INC. N88'04'39"E 139.00 I LEGEND TP-1 TEST PIT LOCATION SCALE" 1"=30' I -N- 7376 WALNUT AVENUE K 714-M-tseu RECORD OF SUBSURFACE EXPLORATION Ul isture % dry wt.) c- Date 1/19/2011 Geotechnical Engineering Investigation (U Q. E CO isture % dry wt.) ' Desi Q. 7500 Jerez Court CO S ^ Q Q) Q Carlsbad, California U B Work Order 263810 Test Pit No. 1 Description of Earth Materials 0 2 0- r, TOPSOIL, WET BLACK CLAY, LOOSE, SOME SMALL ROOTS 1- 3' BLACK SILTY CLAY FIRM DAMP, PLASTIC FEEL 14 113 4 6 8 3-8', BROWN CLAYEY SILT, FIRM MOIST DENSE End of Test Pit at 8' Feet. No Ground Water. No Caving. RECORD OF SUBSURFACE EXPLORATION m Date 1/19/2011 Geotechnical Engineering Investigation ample; listure dry w 1 Desr ipth (F 7500 Jerez Court CO C Q ILI Q Carlsbad, California U B Work Order 263810 Test Pit No. 2 j Description of Earth Materials • 0 — 2 SURFACE: WEED COVERED VACANT LOT 0-6" TOPSOIL, BLACK WET CLAY WITH SMALL ROOTS 6" 3': BLACK SILTY CLAY, FIRM DAMP SOMEWHAT PLASTIC FEEL • 12 108.1 4 — 6 — 8 — 10 — 3'-6' BROWN CLAYEY SILT, MOIST FIRM , SLIGHTLY PLASTIC 6'-10'LIGHT BROWN SILT. STIFF, MOIST, SOME BINDER ' NON-PLASTIC End of Test Pit at 10 Feet. No Ground Water. No Caving. • VERY HARD DIGGING STRATA - TECH, INC. STRATA-TEC H,INC C3EaCONSUl_TANTS APPENDIX A This appendix contains a description of the field investigation, laboratory testing procedures and results, site plan, and exploratory logs. FIELD INVESTIGATION The field investigation was performed on January 19, 2011, consisting of the excavation of two exploratory henches at locations shown on the attached Site Plan, Plate 2. As excavation progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing. Sample Retrieval- Backhoe Undisturbed samples of eartii materials were obtained at frequent intervals by driving a thin- walled steel sampler by the hydraulic action oftiie backhoe bucket. The material was retained in brass rings of 2.41 inches inside diameter and 1.00 inch height. The central portion ofthe sample was in close-fitting, watertight containers for transportation to the laboratory. Descriptions of tiie soils encountered are presented on tiie attached boring Logs. The data presented on these logs is a simplification of acttial subsurface conditions encountered and apphes only at tiie specific boring location and the date excavated. It is not wananted to be representative of subsurface conditions at other locations and tunes. Laboratory Testing Field samples were examined in the laboratory and a testing program was tiien estabhshed to develop data forpreliminary evaluation of geotechnical conditions. Moisture Density Field moistijre content and dry density were determined for each of tiie undisttirbed soil samples. The dry density was detennined in pounds per cubic foot. The moisture content was determined as a percentage ofthe dry soil weight. The results oftiie tests are shown in tiie test results section of this appendix. , Compaction Character Compaction tests were performed on bulk sample of the existing soil in accordance with ASTM D1557-07. The results oftiie tests are shown in tiie test results section of this appendbc. Shear Strength The ultimate shear strengtiis ofthe soil, remolded soil, highly weatiiered bedrock and bedrock was determined by performing direct shear tests. The tests were performed in a strain-controlled ASPHALT CONCRETE PAVEMENT DESIGN R value = 35 1. Design for auto parkiriQ T.I. = 4 Gf = 2.5 G.E. required = 0.0032 (T.I.) (100 - R) = 0.83 ft Try Thickness of AC = 3 inches G.E. from AC = 3 /12 * 2.5 = 0.63 ft Thickness of AB needed = ( 0.83 - 0.63) / 1.1 * 12 = 2.2 inches 2. Design for driveways T.I. = 5.5 Gf = 2.32 G.E. r^uired = 0.0032 (T.I.) (100 - R) = 1.14 ft Try Thic;kness of AC = 3 inches G.E. frqm AG = 3 /12 * 2.32 = 0.58 ft Thickness of AB needed = (1.14 - 0.58) /1.1 * 12 = 6.1 inches 3. Design for heavv trucks T.I. = 7.5 Gf = 2.01 G.E. required = 0.0032 (T.I.) (100 - R) = 1.56 ft Try Thickness of AC = 3 inches G.E. from AC = 3 /12 * 2.01 = 0.5 ft Thickness of AB needed = (1.56 - 0.5) /1.1 * 12 = 11.6 inches Use 3 inches Use 6 inches Use 12 inches Geotechnical Engineering Investigation 7500 Jerez Court Carlsbad, California Work Order 262310 Geotechnical Engineering Investigation 7500 Jerez Court Carlsbad, California STRATA ' TECH, INC. \ STRATA G E D C D N S - T E G H , U U T A N T I N C s machine manufactured by GeoMatic. The rate of defomiation was 0.005 inches per minute. Samples were sheared under varying confming pressure, as shown on the "Shear Test Diagrams". The samples indicated as saturated were artificially saturated m the laboratory and were shear under submerged conditions. The results of tests are based on 80 percent peak strength or ultimate strength, whichever is lower, and are attached. In addition, a shear was performed on an upper layer sample remolded to 90-percent ofthe laboratory standard with low confining pressure. TEST RESI LTS Maximum Density/Optimum Moisture (ASTM:D-1557-07j Trench Depth in Feet Maximum Density Optimum Moisture :(%) 2 1-3 126 U.O In-Situ Dry Densitv/ Moisture Trench Depth in Feet Dry Density :::'-T^^-;;-''v-:;:-|icif Moisture 1 • 3.5 113.0 14.01 2 ^-3 •' ' ' 108.1 12.0 Direct Shear Trench " Deptii in Feet Cohesion (psf) Angle of Intemal Friction (degrees) 2 2 200 30 ACTIVE RETAINING WALL PRESSURE Proposed Pool WALL Free Bodv Diagram PA ^ H = 5 ft Hc = 2 ft a = 54.1 ° F.S. = 1.75 ^m = 130 pcf = 0.13 C = 200 psf = 0.2 * = 30° C^L c /K;"., X /-,. W = a + b a = 45 + / 2 Cm = C/F.S. = 0.11 ksf . (j), = Tav-UTav(t)/O.E.)= 18.26 degrees \ D = (H-Hc)tan(90°-a)= 2.17 ft : L = ((H-Hc)^ + D^)^'' = 3.7ft T W = AYm = 0.5D(H + Hc)Y„= 0.99 kips/LF ! t a = CmLsin(90°+>?.)/sin(S->?„)= 0.66 kips/LF b = W - a = 0.33 kips/LF PA = b tan ( a - (l)n,) = 0.24 kips/LF : Design EFP = 2 PA / H ' = 19-2 pcf Use 20 pcf (30 min.) Geotechnical Engineering Investigation Work Order 262310 1 7500 Jerez Court 1 Carlsbad, California STRATA - TECH, INC. ALLOWABLE BEARING CAPACITY 130 pcf 200 psf 30 degrees 2 feet 1.0 foot 3.0 Reference: "Soil Mechanics in Engineering Practice", Terzaghi and Peck, 1967 pages 222 and 223. Bearing Material: compacted fill Properties: Wet Density (g) Cohesion (C) Angle of Friction (>?) Footing Depth (D) Footing Width (B) Factor of Safety = Calculations - Ultimate Bearing Capacity •* from figure 33.4 on page 222 Nc= 30.14 Nq= 18.4 Nv)o = 22.4 = 1.2 C Nc + ^ D Nq + 0.4 B N (Square Footing) = 1.2 * 200 * 30.14 + 130 * 2 * 18.4 + 0.4 * 130 * 1 * 22.4 = 7233 + 4784 + 1164= 13181 psf Allowable Bearing Capacity for Square Footing Qaii= Qu/F-S- = 4393 psf Use 1500 psf (Settlement Control) Qu = 1.0 C Nc + X)o D Nq + 0.5 X)o B N (Continuous Footing) = 1.0*200*30.14 + 130*2* 18.4 + 0.5* 130*1 * 22.4 = 6028 + 4784 + 1456 = 12268 psf Allowable Bearing Capacity for Continuous Footing Q3„= Q„/F.S. = 4089 psf Use 1500 psf (Settlement Control) Increases: 440 psf / ft In depth over 2 feet 0 psf / ft in depth over 1 foot Geotechnical Engineering Investigation Work Order 262310 7500 Jerez Court 1 Carlsbad, California STRATA - TECH, INC. r STRATA -TEG H , I N G QEDCON SUL.TANTS APPENDIX B SPECIFICATIONS FOR GRADING SITE CLEARING All existing vegetation shall be stripped and hauled from the site. PREPARATION After the foundation for tiie fill has been cleared, plowed or scarified, it shall be disced or bladed until it is uniform and free from large clods, brought to a proper moisture content and compacted to not less tiian 90 percent of tiie maximum dry density in accordance witii ASTM:D-1557-02 (5 layers - 25 blows per layer; 10 lb. hammer dropped 18"; 4" diameter mold). MATERIALS On-site materials may be used for fill, or fill materials shall consist of materials approved by tiie Soils Engineer and may be obtained from the excavation of banks, borrow pits or any otiier approved source. The materials used should be free of vegetable matter and otiier deleterious substances and s^all not contain rocks or lumps greater than 8 inches in maxunum dunension. PLACING, SPHEADING, AND COMPACTING FILL MATERIALS Where natural slopes exceed five horizontal to one vertical, tiie exposed bedrock shall be benched prior to placing fill. The selected fiii material shall be placed in layers which, when compacted, shall not exceed 6 inches in tiiickness. Each layer shall be spread evenly and shall be tiioroughly mixed during tiie spreading to ensUre uniformity of material and moisture of each layer. Where moisture of the fill material is below tiie limits specified by the Soils Engmeer, water shall be added until the moishire content is as required to ensure tiiorough bonding and thorough compaction. |. Where moistiirexontent oftiie fill material is above tiie limits specified by tiie Soils Engineer, tiie fill materials shall be aerated by blading or otiier satisfactory metiiods xmtil tiie moistiire content is as specified. After each layer; has been placed, mixed and spread evenly, it shall be tiioroughly compacted to not less than 90 percent oftiie maximum dry density in accordance with ASTM:D-1557-02 (5 layers - 25 blows per layer; 10 lbs. hammer dropped 18 inches; 4" diameter mold) or other density tests which will attain equivalent results. STRATA-TEGHjlNC QEOCONSU t. TANTS Compaction shall be by sheepsfoot roller, multi-wheel pneumatic tire roller or otiier types of acceptable rollers. Rollers shall be of such design that they wiU be able to compact tiie fill to tiie specified ciensity^ on grade should'be rolled to a dense, smooth surface. The outside of aU fill slopes shaU be compacted by means of sheepsfoot rollers or otiier suitable obtained. ,! ' The grading specifications should be a part of the project specifications. The Soil Engineer shall review the grading plans prior to grading. INSPECTION] The Soil Engineer shall provide continuous supervision oftiie site clearing and grading operation lTl^STI\e^fy ±^ grading was done in accordance witii tiie accepted plans and specifications. , SEASONAL LIMITATIONS No fill materiai shall be plaped, spread or rolled during ^f^^^ work is intemipted by heavy rains, fill operations shall not be resumed untti the field tests by the Sots EnSS?£tote tiie moistiire content and density of tiie fill are as previously specified. EXPANSIVE ^pIL CONDITIONS Whenever expansive soil conditions are encountered, tiie moistiire content of tiie fi^U or ^:^:LrsTs^.n be as recommended in tiie expansive soil recommendations mcluded herewith.