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Home My WebLink AboutCDP 2017-0044; THOMPSON GEESBREGHT ADU; SUPPLEMENTAL REPORT FOR PROPOSED GRADING; 2018-01-08COAST GEOTECHNICAL ______ ___, RECORD COPY CONSULTING ENGINEERS AND GEOLOGISTS January 8, 2018 John and Priscilla Geesbreght 4056 Skyline Road Carlsbad, CA 92008 JE.B.}~lf..( lnitili ' RE: SUPPLEMENTAL REPORT FOR PROPOSED GRADING Proposed Guest House 4056 Skyline Road Carlsbad, California Reference: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Guest House and Garage 4056 Skyline Road Carlsbad, California Prepared by Coast Geotechnical Dated July 26, 2017 RECET" 'ED MAY 16 70\8 l AND DEVEL .. ' !ENT ENGINEE:.i-..1i~G Dear Mr. and Mrs. Geesbreght: This Supplemental Report presents geotechnical recommendations for the design changes that include site grading. This report also addresses potential slope instability and structural impacts resulting from concentrating drainage into infiltration basins or dry wells, as requested by the city of Carlsbad. If you have any questions, please do not hesitate to contact us at (858) 755-8622. This opportunity to be of service is appreciated. Nati "JC.,,,U//.L.YI/1 Mark Burwell, C.E.G. Engineering Geologist P.O. BOX 230163 • ENCINITAS, CALIFORNIA 92023 • (858) 755-8622 Coast Geotechnical PROPOSED DEVELOPMENT January 8, 2018 W.O. P-674617 Page 2 of 8 Design concepts have been revised from construction of the proposed guest house on sloping terrain with a pier and grade beam foundation to construction on a level, graded pad with a continuous wall foundation and a slab on grade floor. A review of the revised site plan prepared by Caroline Dooley, Architect, suggest grading will include a cut slope descending to a cut/fill transitional building pad. Cuts up to approximately 3.0 vertical feet and fills up to approximately 2.0 feet are anticipated. The project will also include site retaining walls and steps. Proposed grading and the general subsurface geologic conditions are depicted on the enclosed Cross Section A-A' (Plate D). CONCLUSIONS 1) In view of the geotechnical conditions, it is recommended that the existing fill, soil, and old paralic deposits in the building footprint be removed and replaced as properly compacted fill. Removal depths in the building pad are anticipated to be on the order of 4.0 feet. It is suggested that removals and recompaction include the front concrete patio and rear deck. 2) Disturbed soils resulting from the demolition of structures and utility lines should be removed and replaced as properly compacted fill. 3) Our experience with this type of lot development and geotechnical conditions suggest that varying degrees of seepage can develop after construction. Post-construction seepage and/or saturated ground conditions can adversely affect foundations and concrete flatwork. Coast Geotechnical January 8, 2018 W.O. P-674617 Page 3 of 8 Therefore, special consideration should be provided for surface and subsurface drainage during the design and construction phases. RECOMMENDATIONS Removals and Recompaction The existing fill, soil and weathered old paralic deposits in the building pad should be removed and replace as properly compacted fill. Removals should extend a minimum of 5.0 feet beyond the building footprint. The maximum depths of removals are anticipated to be on the order of 4.0 feet. However, a minimum of 18 inches of fill should underlie the base of the deepest footing. The front concrete patio and rear deck are underlain by fill and weathered old paralic deposits. These deposits should be removed and replaced as properly compacted fill. Most of the existing earth deposits are generally suitable for reuse, provided they are cleared of all vegetation, debris, and thoroughly mixed. Prior to placement of fill, the base of the removals should be observed by a representative of this firm. Additional overexcavation and recommendations may be necessary at that time. The exposed bottom should be scarified to a minimum depth of 6.0 inches, moistened as required, and compacted to a minimum of 90 percent of the laboratory maximum dry density. Other areas of exterior improvements underlain by fill and weathered old paralic deposits may require remedial grading. Additional recommendations may be necessary during the grading phase. A copy of our grading guidelines is included and should be considered part of this report. Coast Geotechnical Temporary Slopes and Excavation Characteristics January 8, 2018 W.O. P-674617 Page 4 of 8 Temporary excavation, which expose fill, debris deposits, and weathered old paralic deposits should be trimmed to a gradient of 1: 1 (horizontal to vertical) or less depending upon conditions encountered during grading. The unweathered old paralic deposits may be excavated to a vertical height of 5.0 feet. The temporary slope recommendations assume no surcharges are located or will be placed along the top of the slope within a horizontal distance equal to one half the height of the slope. Old paralic deposits are dense below the weathered zone. However, based on our experience in the area, the sandstone is rippable with conventional heavy moving equipment in good working order. Foundations The following design parameters provided in the Preliminary Geotechnical Report remain valid. The base of footings should be maintained a minimum horizontal distance of l O lateral feet to the face of the nearest slope. Sulfate and Chloride Tests The results of our sulfate test performed on representative samples are presented on Tables 8, in Appendix B of the Preliminary Geo technical Report. The results of testing suggest the soils have a soluble sulfate content of 0.001 percent. Soils with a soluable sulfate content ofless than 0.1 percent are considered to be negligible. Coast Geotechnical Slabs on Grade (Interior and Exterior Revised) January 8, 2018 W.O. P-674617 Page 5 of 8 Slab on grade should be a minimum of 5.0 inches thick and reinforced in both directions with No. 3 bars placed 18 inches on center in both directions. Exterior slabs on grade should be a minimum of 4.5 inches thick and reinforced with No. 3 placed 18 inches on center in both directions. The slab should be underlain by a minimum 2.0-inch coarse sand blanket (S.E. greater than 30). Where moisture sensitive floors are used, a minimum 10.0-mil Visqueen, Stego, or equivalent moisture barrier should be placed over the sand blanket and covered by an additional two inches of sand (S.E. greater than 30). Utility trenches underlying the slab may be backfilled with on-site materials, compacted to a minimum of 90 percent of the laboratory maximum dry density. Slabs should be reinforced as indicated above the provided with saw cuts/expansion joints, as recommended by the project structural engineer. All slabs should be cast over dense compacted subgrades. At a minimum, interior slabs should be provided with softcut contraction/controljoints consisting of sawcuts spaced 10 feet on center maximum each way. Cut as soon as the slab will support the weight of the saw, and operate without disturbing the final finish, which is normally within 2 hours after final finish at each control joint location or 150 psi to 800 psi. The softcuts should be a minimum of 3/4 inch in depth, but should not exceed 1 inch in depth. Anti-ravel skid plates should be used and replaced with each blade to avoid spalling and raveling. A void wheeled equipment across cuts for at least 24 hours. Provide re-entrant comer (270 degrees comers) reinforced for all interior slabs consisting of minimum two, 10-feet long No. 3 bars at 12 inches on center with the first bat placed 3 inches from re-entrant corner (see Plate A). Re-entrant corners will depend on slab geometry and/or interior column locations. Exterior slabs should be provided with weakened plane joints at frequent intervals in accordance with the American Concrete Institute (ACI) guidelines. Coast Geotechnical January 8, 2018 W.O. P-674617 Page 6 of 8 Our experience indicates that the use of reinforcement in slabs and foundations can reduce the potential for drying and shrinkage cracking. However, some minor cracking is considered normal and should be expected as the concrete cures. Moisture barriers can retard, but not eliminate moisture vapor movement from the underlying soils up through the slab. Proposed Garage Previous recommendations for the garage development appear applicable provided significant design changes are not implemented. Slope Stability Impacts From Infiltration The descending slopes on the subject property are underlain by fill, soil and weathered old paralic deposits. These fine and medium-grained sand deposits range from a moderately dense condition to a loose sand. Our review of the Landslide Hazards Map, Oceanside-San Luis Rey (Tan and Griffen, 1995) suggests the site is located within Susceptibility Area 3-1, where slopes are generally susceptible. We suggest that collected storm water not be infiltrated into these deposits from basins or dry wells. Saturated soil conditions can adversely affect slope stability, as well as foundations and concrete flatwork. We suggest that storm water drainage be filtrated into a bio-retention basin that incorporates an impervious liner. A typical bio-retention detail is included in this report as Plate G. Actual drainage design for the development should be provided by the project architect or engineer. Coast Geotechnical LIMITATIONS January 8, 2018 W.O. P-674617 Page 7 of 8 This report is presented with the provision that it is the responsibility of the owner or the owner's representative to bring the information and recommendations given herein to the attention of the project's architects and/or engineers so that they may be incorporated into plans. If conditions encountered during construction appear to differ from those described in this report, our office should be notified so that we may consider whether modifications are needed. No responsibility for construction compliance with design concepts, specifications, or recommendations given in this report is assumed unless on-site review is performed during the course of construction. The subsurface conditions, excavation characteristics, and geologic structure described herein are based on individual exploratory excavations made on the subject property. The subsurface conditions, excavation characteristics, and geologic structure discussed should in no way be construed to reflect any variations which may occur among the exploratory excavations. Please note that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature and other factors not evident at the time measurements were made and reported herein. Coast Geotechnical assumes no responsibility for variations which may occur across the site. The conclusions and recommendations of this report apply as of the current date. In time, however, changes can occur on a property whether caused by acts of man or nature on this or adjoining properties. Additionally, changes in professional standards may be brought about by legislation or the expansion of knowledge. Consequently, the conclusions and recommendations of this report may Coast Geotechnical January 8, 2018 W.O. P-674617 Page 8 of 8 be rendered wholly or partially invalid by events beyond our control. This report is therefore subject to review and should not be relied upon after the passage of two years. The professional judgments presented herein are founded partly on our assessment of the technical data gathered, partly on our understanding of the proposed construction and partly on our general experience in the geotechnical field. However, in no respect do we guarantee the outcome of the project. This study has been provided solely for the benefit of the client and is in no way intended to benefit or extend any right or interest to any third party. This study is not to be used on other projects or extensions to this project except by agreement in writing with Coast Geotechnical. Enclosures: Grading Guidelines Plate A Plate B Plate C Plate D (Cross Section A-A') Geotechnical Map (Rear Pocket) ENCLOSURES Grading Guidelines Grading should be performed to at least the minimum requirements of the local governing agencies, the California Building Code, 2016, the geotechnical report and the guidelines presented below. All of the guidelines may not apply to a specific site and additional recommendations may be necessary during the grading phase. Site Clearing Trees, dense vegetation, and other deleterious materials should be removed from the site. Non-organic debris or concrete may be placed in deeper fill areas under direction of the Soils engineer. Subdrainage • During grading, the Geologist and Soils Engineer should evaluate the necessity of placing additional drains. • All subdrainage systems should be observed by the Geologist and Soils Engineer during construction and prior to covering with compacted fill. • Consideration should be given to having subdrains located by the project surveyors. Outlets should be located and protected. Treatment of Existing Ground • All heavy vegetation, rubbish, and other deleterious materials should be disposed of off site. • All surficial deposits including alluvium and colluvium should be removed unless otherwise indicated in the text ofthis report. Groundwater existing in the alluvial areas may make excavation difficult. Deeper removals than indicated in the text of the report may be necessary due to saturation during winter months. • Subsequent to removals, the natural ground should be processed to a depth of six inches, moistened to near optimum moisture conditions, and compacted to fill standards. Fill Placement • Most site soil and bedrock may be reused for compacted fill; however, some special processing or handling may be required (see report). Highly organic or contaminated soil should not be used for compacted fill. • Material used in the compacting process should be evenly spread, moisture conditioned, processed, and compacted in thin lifts not to exceed six inches in thickness to obtain a uniformly dense layer. The fill should be placed and compacted on a horizontal plane, unless otherwise found acceptable by the Soils Engineer. • If the moisture content or relative density varies from that acceptable to the Soils engineer, the Contractor should rework the fill until it is in accordance with the following: • Moisture content of the fill should be at or above optimum moisture. Moisture should be evenly distributed without wet and dry pockets. Pre-watering of cut or removal areas should be considered in addition to watering during fill placement, particularly in clay or dry surficial soils. • Each six inch layer should be compacted to at least 90 percent of the maximum density in compliance with the testing method specified by the controlling governmental agency. In this case, the testing method is ASTM Test Designation D-1557-91. • Side-hill fills should have a minimum equipment-width key at their toe excavated through all surficial soil and into competent material (see report) and tilted back into the hill. As the fill is elevated, it should be benched through surficial deposits and into competent bedrock or other material deemed suitable by the Soils Engineer. • Rock fragments less than six inches in diameter may be utilized in the fill, provided: • They are not placed in concentrated pockets; • There is a sufficient percentage of fine-grained material to surround the rocks; • The distribution of the rocks is supervised by the Soils Engineer. • Rocks greater than six inches in diameter should be taken off site, or placed in accordance with the recommendations of the Soils Engineer in areas designated as suitable for rock disposal. • In clay soil large chunks or blocks are common; if dimensions exceed 6 inches then they are considered oversized. Sheepsfoot compactors or other suitable methods should be used to break up the blocks. • The Contractor should be required to obtain a minimum relative compaction of 90 percent out to the finished slope face of fill slopes. This may be achieved by either overbuilding the slope and cutting back to the compacted core, or by direct compaction of the slope face with suitable equipment. If fill slopes are built "at grade" using direct compaction methods then the slope construction should be performed so that a constant gradient is maintained throughout construction. Soil should not be "spilled" over the slope face nor should slopes be "pushed out" to obtain grades. Compaction equipment should compact each lift along the immediate top of slope. Slopes should be vertically back rolled approximately every 4 feet as the slope is built. Density tests should be taken periodically during grading on the flat surface of the fill three to five feet horizontally from the face of the slope. In addition, if a method other than over building and cutting back to the compacted core is to be employed, slope compaction testing during construction should include testing the outer six inches to three feet in the slope face to determine if the required compaction is being achieved. Finish grade testing of the slope should be performed after construction is complete. Each day the Contractor should receive a copy of the Soils Engineer's "Daily Field Engineering Report" which would indicate the results of field density tests that day. • Fill over cut slopes should be constructed in the following manner: • All surficial soils and weathered rock materials should be removed at the cut-fill interface. • A key at least 1 equipment width wide (see report) and tipped at least 1 foot into slope should be excavated into competent materials and observed by the Soils Engineer or his representative. • The cut portion of the slope should be constructed prior to fill placement to evaluate if stabilization is necessary. The contractor should be responsible for any additional earthwork created by placing fill prior to cut excavation. • Transition lots ( cut and fill) and lots above stabilization fills should be capped with a four foot thick compacted fill blanket (or as indicated in the report). • Cut pads should be observed by the Geologist to evaluate the need for overexcavation and replacement with fill. This may be necessary to reduce water infiltration into highly fractured bedrock or other permeable zones, and/or due to differing expansive potential of materials beneath a structure. The overexcavation should be at least three feet. Deeper overexcavation may be recommended in some cases. • Exploratory backhoe or dozer trenches still remaining after site removal should be excavated and filled with compacted fill if they can be located. Grading Observation and Testing • Observation of the fill placement should be provided by the Soils Engineer during the progress of grading. • In general, density tests would be made at intervals not exceeding two feet of fill height or every 1,000 cubic yards of fill placed. This criteria will vary depending on soil conditions and the size of the fill. In any event, an adequate number of field density tests should be made to evaluate if the required compaction and moisture content is generally being obtained. • Density tests may be made on the surface material to receive fill, as required by the Soils Engineer. • Cleanouts, processed ground to receive fill, key excavations, subdrains, and rock disposal should be observed by the Soils Engineer prior to placing any fil l. It will be the Contractor's responsibility to notify the Soils Engineer when such areas are ready for observation. • A Geologist should observe subdrain construction. • A Geologist should observe benching prior to and during placement of fill. Utility Trench Baclifill Utility trench backfill should be placed to the following standards: • Ninety percent of the laboratory standard if native material is used as backfill. • As an alternative, clean sand may be utilized and flooded into place. No specific relative compaction would be required; however, observation, probing, and if deemed necessary, testing may be required. • Exterior trenches, paralleling a footing and extending below a 1: 1 plane projected from the outside bottom edge of the footing, should be compacted to 90 percent of the laboratory standard. Sand backfill, unless it is similar to the inplace fill, should not be allowed in these trench-backfill areas. Density testing along with probing should be accomplished to verify the desired results. ... :~ NOTES: (a) RE-ENTRANT CORNER REINFORCEMENT NO. 3 BAllS PLACED MID-HEIGHT IN SLAB ISOlAilON JOINTS CONTRACTION JO'NTS (c) I NO SCALE I (6) RE-ENTRANT CORNER CRACI< 1. Isolation joints around the columns should be either circular as shown in (a) or diamond shaped as shown in (b). If no isolation joints are used around columns, or if the corners of the isolation joints do not meet the contraction joints, radial cracking as shown in (c) may occur (reference ACI). 2. In order to control cracking at the re-entrant corners(·+-/ -270 degree corners), provide reinforcement as shown in (c). 3. Re-entrant corner reinforcement shown herein is provided as a general guideline only and is subject to verification and changes by the project architect and / or structural engineer based upon slab geometry, location, and other engineering and construction factors. TYPICAL ISOLATION JOINTS AND RE-ENTRANT CORNER REINFORCE1\1ENT .. ' PLATE A SPECIFICATIONS FOR CAI.TRANS CIASS 2 PERMEABLE MATERIAL (68•1,025) U.S. STANDARD SIEVE SIZE 1· 3/4 318 No. 4 No.8 No.30 No.SO No.200 1'PASSING 100 9().100 40-100 25--40 18-33 5.15 0.7 0-3 SAND EQUIVALENT > 75 FILTER MATE~ 3/4" • If CRUSHED ROCKS (WRAPPcD IN FILTER FABRIC OR CAI.TRANS CLASS 2 PERMEABlf MATERIAl.5 (SEE SPECIFICATIONS) WATERPROOFING (TYP) FINISH GRADE 6"MIN. CONCRETE-LINED DRAINAGE DITCH FILTER MATERIAL, 3/4" · lf CRUSHED ROCl<S (WRAPPED IN FILTER FABRIC OR CAL TRANS CLASS 2 PERMEABLE MATERIALS (SEE SPECIFICATIONS) WATERPROOFING (TYP) PROPOSED GRADE 61 MIN. CONSTRUCTION SPECIFICATIONS: I NO SCALE I I NOSOJ.f I GROUND SURFACE MIN. 901' COMPACTED FILL APPROVED FILTER FABRIC (MIIWI U0N) 12" OVERLAP, TYP. 4• r.lC PERFORATED PIPE MIN. (SCH 40 OR SDR35) MIN. 1 /'l"I. FALL TO APPROVED OUTtfT (SEE REPORT) NATURAL OR GRADED SLOPE TEMPORARY l : l CUT SLOPE PROPERLY COMPACTED (MIN. 90%) BACKFILLED GROUND ----BENCH AND TIGHTLY KEY INTO TEMPORARY BACKCUT AS BACKFILLING PROGRESSES APPROVED FILTER FABRIC (MIRAFI 140N) 12° OVERLAP, TYP. '-------4° r./C PERFORATED PIPE MIN. (SOi 40 OR SDR35) MIN. 1 n% FALL TO APPROVED OlffiET (SEE REPORT) 1. Provide granular, non-expansive backfill soil in 1: 1 gradient wedge behind wall. compad backfill to minimum 90% of laboratory standard. 2. Backdrain should consist of 41 diom~ttir PVC pipe (Schedule 40 or equivalent) with perforations down. Drain to suitable at minimum½%. Provide 3/41 -1 ½• crushed ~ocks filter materials wrapped in fabric (Mirofi 1 ◄ON or equivalent). Delete . filter fabric wrap if Caltrons Closs 2 permeable material is used. Compact Class 2 permeable material to minimum 90% of laboratory standard. 3. Seal bock of wall with approved waterproofing in accordance with architect's specifications .. 4. Provide positive drainage to disallow ponding of water above wall. Drainage to flow away from wall ot minimum 2%. Provide concrete-lined droinoge ditch for slope toe retaining wells. 5. Use 1 ½ cubic feet per foot with granular backfill soil and 4 cubic foot per foot if expansive backfill is used. ·-·----·-. TYPICAL RETAINING WALL BACK DRAINAGE P9 0 JECT NOz FIGURE" NO: · H ·p-14617 LATE B . ' 18" HOPE STORM DRAIN RISER W/A TR/UM 12• MAX PONDED WATER DEPTH VARIES ' ., 'NLEl :' PIPE · HOPE OR PVC GEOMEMBRAN£ THICKNESS AT LEAST JOA/IL 3• UINIMUN (T'YP) AGGREGATE BELOW UNDERDRAJN TO A VOID CLOGGING Ml~, DE~~··,.~~ J . SOIL FILTER MIX 6. PERFORATED PIPE SLOPED AT 0.5% IN ¾" AGGREGATE BASE GRA~L BED. CONNECTED TO STORM DRAIN. Schematic And Conceptual Only No-Scale PR JECT. NO: P-674617 DATE: 1 /8/18 OUTLET P!PE PLATE C ). A 310 300 I-UJ UJ ~ z z 0 I-< > 290 UJ ...J UJ 280 COAST GEOTECHNICAL 5931 Sea Lion Place, Suite 109 Carlsbad, CA 92010 4056 Skyline Road, Carlsbad I ■■ 0 S I ---------------I I I : PROPOSED : I GUEST HOUSE I Cross-Section A -A' 10 Scale: 1 "= 1 O' 20 Feet 30 Legend _ ?-?-Approximate contact · Test Pit 40 .•. --.... Geologic Units [W~fjj Artificial Fill I.: ·o_·v~p_··.· 1 Quaternary Very Old Paralic Deposits, Unit 12 A' PLATED W.O. P-674617 ----~-----------··-------· --------- _ .. _. ------· -·-· ·-·- / /,,------.., ·-~-) . .,__ // ', -~- / ) -----------· ·-,' ---,/ \ STANDARD PROJECT BMP REQUIREMENTS (FROM COMPLETED FORM E36) SC-1 SC-5 SD-1 SD-2 I SD-3 I SD-4 I ~ PREVENTION OF ILLICIT DISCHARGES INTO THE MS4 · PROTECT TRASH STORAGE AREAS FROM RAINFALL RUN-ON, RUN-OFF, WIND DISPERSION MAINTAIN NATURAL DRAINAGE PATHWAYS CONSERVE NATURAL AREAS, SOILS & PLANTS MINIMIZE IMPERVIOUS AREAS MINIMIZE SOIL COMPACTION IMPERVIOUS AREA DISPERSION ', -~- I I I . r I -I: i 1-- I ·--.. I I ·,. 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I /; ., -· . \ ' (E) CHAIN-i ' LINK FENCE '! ' \ \ (Ei CONC. PAVING ' ' I I --,--~-------·-"/ , I -=== ---+! __ ,__ -----:o -----,---------r ___ --,. ----;'-,1 ' I / -/ -,--.-/,-/ / / . ! / ' ,I / / / (El ELECTRICAL~• / / , / FROM SKYLINE (El GAS LINE--·/// 1 FROM SKYLINE / / (E) WATER LINE~ / FROM SKYLINE / (El SEWER LATERAL--' TO SKYLINE ,---____ , __ _ UTILITY NOTES EXISTING SEWER GAS, AND ELECTRICAL SERVICES INSTALLED IN EXISTING EASEMENT FROM SKYLINE ROAD. UPGRADE EXISTING ELECTRICAL SUPPLY AS NOTED. \ LEGEND ' / 302' ~ D.G (E) (P) \ PROPOSED 1j,CAR GARAGE \ 1(01 .0' T.O.C. 300,)?5' PAD EL --;--+--~----·~·--,--_,-~--,--·~--NBr39·10"\IV 125 00' PROPERTY LINE \ -:·_ :=-' :::::· ,. / ! I I 7-,..----~ '"-. ·---'-r-,1-_10•ls1DE YARD SET~ACK LINE / V\ ! ·-.. 295.0' "' ' I I ., 294.5' '" / (P) R ----tr-294_1·• -------\-_-. '' _/i ', " I i \ SD-5 I , \ \ \ \ '~ \\ \ DG. TO .1 _\\ \ REMOVED' . \/VALL ( 3 ~0 S.F.~ T.sO.W. ~ ;e'? 11 / ~ , x1' . 'i_) 295.0' 'y ,, DISPERSE / I I ·/ \1 / \ ;---FLOW (TYJ;-1 $ /\ / · "v"'.____ TO s,1-9Pc ,/ / ~ \ / \' ',.,_~~cfi .·· II w # } • ' / \ I .,_ 'I( ?rs~l~E , · I ' i ,I ' I •1 ' \&"' \ 1 "-,. ~, f-j.0TE #1 / ~ / I I ,, I ;· -;' !\ / J/ // \ // / I ' [1\, ,· I ;1/ / ~ I 1 · 42'-3" ; \ I ,J/;' <,,/ I 7''--+----~1~=-=-r----'-~------,-----t-,f, \ i ,§'; "-.. I I ) I /' ~ ,;./ / / / / / \ / \ I .··~ I / /'I SD-5 ,I / I / \ _/ I ,I_ ·/ '\ , ... '-ROOF ABOVE ·/ <:;:;..JC/ C" ',C Ti -,,DA-, '",[)).~H-Ef ' '' , FLOWTO LANDSCAPE , I i ,/ I ,I , / / . I / I -!- (Qvop} I • Sl!l-2 SD-1 / i • ' EXISTING L.AiNDSCA~ING TO IREMAI~, TYP. ' I ! I I \ ~ I I -,--' -,,--,- ', ! I ! -,- / \ .\ • i / ' ; I r \~ I rf• I ji \~ \ ls \ I (I) i' "" ;I ell ' ')> I 9z Ii 1 I / / , I I NA1 ' . I I I / I I i \ I I / I \ \ I \ I _( _ _j ' ,-' \ I I 1 I ./ I I ' \ \ A I, ' CDP 2017-0044 TP-1 Qaf -. .-: ,-,., - Legend A' ◄ Approx. Tes:: Pit Location Geologic Cross-Section Artificial Fill Qvop Very Old Paralic Deposit Project No. G-674617 \ I I -·-• --· -~~---_--.L _, __ _J SITE DRAINAGE NOTES SITE DRAINAGE FLOW LINE 1) GRADE TO SLOPE AWAY FROM ALL STRUCTURES AT 3% FOR 5'-0". EXISTING CONTOUR LINE (DASHED) 2) ALL ROOFS DRAIN TO SITE LANDSCAPE MODIFIED CONTOUR LINE (SOLID) (SHEET-FLOW) TO DISPERSE LANDSCAPE FLOW. DECOMPOSED GRANITE MATERIAL (COMPACTEDJ 3) THE EAST DECK IS ELEVATED ABOVE EXISTING EXISTING GRADE TO ALLOW DRAINAGE THROUGH PROPOSED TO GRADE BELOW ~ Site Plan -SCALE 1"=10' ---·----------~·---------- REV!SJO:\ VJ (L) (L) l? DRA\.\IN(l Ti"TLE - :c SITE PLAN D_-\TE 12-6-17 Cl-JECK.ED DESJGNED DJ{,\\\ U<C '\I lJi\JIBE R A1.0 Sh.CU r-,;fJ. UF COAST GEOTECHNICAL CONSULTING ENGINEERS AND GEOWGISTS July 261\ 2017 John and Priscilla Geesbreght 4056 Skyline Road Carlsbad, CA 92008 RE: PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Guest House and Garage 4056 Skyline Road Carlsbad, California Dear Mr. and Mrs. Geesbreght: In response to your request and in accordance with our Agreement dated May 31 st, 2017, we have performed a preliminary geotechnica1 investigation on the subject site for the proposed residence. The findings of the investigation, laboratory test results, and recommendations for the foundation design are presented in this report. From a geologic and soils engineering point of view, it is our opinion that the site is suitable for the proposed development, provided the recommendations in this report are implemented during the design and construction phases. However, certain geotechnical conditions will require special consideration during the design and construction phases, as indicated by the following: • No grading is proposed for the development of the proposed guest house and garage. • Due to the nature of the underlying Pleistocene deposits, the proposed structures should be supported on cast inplace pile and grade beam type foundation. • Field exploration and laboratory testing performed on samples of onsite earth materials suggest that sands with little or no cohesion may be encountered in pile borings, which will require casing or other methods should caving occur. P.O. BOX 230163 • ENCINITAS, CALIFORNIA 92023 • (858) 755-8622 If you have any questions regarding this report, please do not hesitate to contact us at (858) 755- 8622. This opportunity to be of service is appreciated. Respectfully submitted, COAST GEOTECHNICAL ~di Elizabeth White Project Geologist PRELIMINARY GEOTECHNICAL INVESTIGATION Proposed Guest House and Garage 4056 Skyline Road Carlsbad, California Prepared for: JOHN AND PRISCILLA GEESBREGHT 4056 Skyline Road Carlsbad, CA 92008 Prepared by: COAST GEOTECHNICAL P.O. Box 230163 Encinitas, California 92023 July 261\ 2017 W.O. P-674617 TABLE OF CONTENTS 1. INTRODUCTION ............................................................ 6 2. SCOPE OF SERVICES ....................................................... 6 3. SITE DESCRIPTION AND PROPOSED DEVELOPMENT .......................... 7 3.1 Site Description ....................................................... 7 3 .2 Proposed Development ................................................. 7 4. SITE INVESTIGATION AND LABO RA TORY TESTING ........................... 7 4.1 Site Investigation ...................................................... 7 4.2 Laboratory Testing and Analysis ......................................... 8 5. GEOLOGIC CONDITIONS .................................................... 8 5.1 Regional Geologic Settings .............................................. 8 5.2 Site Geology ......................................................... 9 5.3 Expansive Soil ...................................................... 10 5.4 Groundwater Conditions ............................................... 10 6. GEOLOGIC HAZARDS ..................................................... 10 6.1 Faulting and Seismicity ................................................ 10 6.2 Landslide Potential ................................................... 12 6.3 Liquefaction Potential ................................................. 13 7. CONCLUSIONS ............................................................ 13 8. RECOMMENDATIONS ..................................................... 14 8.1 Temporary Slopes and Excavation Characteristics .......................... 14 8.2 Drilled Cast-In-Place Piles ............................................. 14 8.3 Foundations ......................................................... 15 8.4 Slabs on Grade (Interior and Exterior) .................................... 16 8.5 Lateral Resistance .................................................... 17 8.6 Retaining Walls ...................................................... 17 8.7 Dynamic (Seismic) Lateral Earth Pressures ................................ 17 8.8 Settlement Characteristics ............................................. 19 8.9 Seismic Considerations ................................................ 19 8.10 Preliminary Pavement Design .......................................... 20 8.11 Utility Trench ...................................................... 21 8.12 Drainage .......................................................... 21 8.13 Permeable Interlocking Concrete Pavers (PICP) ........................... 22 8.14 Geotechnical Observations ............................................ 23 8.15 Plan Review ....................................................... 23 9. LIMITATIONS ............................................................. 23 REFERENCES ............................................................... 26 APPENDIX A Figure 1 : Site Location Figure 2: Site Plans Figure 3: Test Pit No. 1 Figures 4a and 4b: Test Pit No. 2 Figure 5: Test Pit No. 3 Figure 6: Fault Map APPENDIXB Laboratory Results Seismic Design Summary and Details Plate A: Cross-section A-A' Plate B: Cross-section B-B' Plate C: Typical Permeable Paver Detail COAST GEOTECHNICAL 1. INTRODUCTION JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 6 of27 This report presents the results of our background review, subsurface investigation, laboratory testing, geotechnical analyses, conclusions regarding the conditions at the subject property, and recommendations for design and construction. The purpose of this study is to evaluate the nature and characteristics of the earth materials underlying the property, the engineering properties of the surficial deposits and their influence on the proposed guest house and garage. 2. SCOPE OF SERVICES The scope of services provided included a review of background data, reconnaissance of the site geology, and engineering analysis with regard to the proposed. The performed tasks specifically included the following: • Reviewing geologic and hazard (seismic, landslide, and tsunami) maps, recently published reports regarding the seismic potential of nearby faults, and a site plan for the project. All background data is listed in the References portion of this report. • Performing a site reconnaissance, including the observation of geologic conditions and other hazards that may impact the proposed project. • Excavation of exploratory test pits consisting oflogging and sampling of earth materials to evaluate the subsurface conditions. • Performing geotechnical laboratory testing of recovered soil samples. • Analyzing data obtained from our research, subsurface exploration, and laboratory testing. • Preparing this preliminary report. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 7 of27 3. SITE DESCRIPTION AND PROPOSED DEVELOPMENT 3.1 Site Description The property is located east of Skyline Road and west of East Pointe Avenue in the city of Carlsbad (Figure 1 ). The property is a rectangular residential lot that descends to the east at an overall grade of about 20 percent for approximately 28 vertical feet. The site includes a two-story residential structure and a detached barn. The site is bounded to the east by East Pointe A venue. The site is bounded along the north, west, and south by developed residential lots. Vegetation consists of shrubs, plants, and grass with several trees. The majority of the eastern slope of the lot is developed for gardening purposes. Drainage is generally by sheet flow to the east. 3.2 Proposed Development Preliminary concept plans for the development of the site were prepared by Caroline Dooley, Architect. The project includes partial demolition of the existing barn, and the construction of a guest house and a detached garage on the site (Figure 2). No grading is proposed and the proposed structures will be constructed along the descending slope. A pile and beam foundation system is anticipated in the design. 4. SITE INVESTIGATION AND LABO RA TORY TESTING 4.1 Site Investigation Site exploration included three (3) exploratory test pits excavated with a mini Caterpillar excavator (Figures 3-5). All three test pits were excavated into the underlying Very Old Paralic Deposits, Unit 12. Test Pits Nos. 1 and 3 were excavated to a maximum depth of 8.5 feet, while Test Pit No. 2 had a maximum depth of 10.5 feet. Earth materials encountered were visually classified and logged by our field project geologist. Undisturbed, representative samples of earth materials were obtained at selective intervals. Chunk samples were obtained by excavating into the desired strata. The samples were retained in waterproof containers and transported to Coast Geotechnical Soils Laboratory for testing and analysis. COAST G EOTECHNICAL 4.2 Laboratory Testing and Analysis JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 8 of27 The laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. All lab descriptions and results can be found in the Laboratory Test Results section of Appendix B of this report. The following tests were preformed: • Classification of Soils • Grain Size Distribution • Moisture/Density • Maximum Dry Density and Optimum Moisture Content • Expansion Index Test • Sulfate Ion Content • Shear Test 5. GEOLOGIC CONDITIONS The geologic conditions at the site are based on our field exploration and review of available geologic and geotechnical literature. 5. 1 Regional Geologic Settings The subject property is located in the Coastal Plains subdivision of the Peninsular Ranges geomorphic province of San Diego. The coastal plain area is characterized by Pleistocene marine terrace landforms. These surfaces are relatively flat erosional platforms that were shaped by wave action along the former coastlines. The step-like elevation of the marine terraces was caused by changes in sea level throughout the Pleistocene and by seismic activity along the Rose Canyon Fault Zone located 5.7 miles west of the coastline. The Rose Canyon Fault Zone is one of many northwest trending, sub-parallel faults and fault zones that traverse the nearby vicinity. Several of these faults, including the Rose Canyon Fault Zone, are considered active faults. Further discussion of faulting in regards to the site is discussed in the Geologic Hazards section of this report. COAST GEOTECHNICAL 5. 2 Site Geology JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 9 of27 Previously published geologic maps conducted by Kennedy and Tan (2008) indicate that the subject property is underlain at depth by middle to early Pleistocene-aged Very Old Paralic Deposits, Unit 12 (Qvop12). The paralic deposits in Test Pit No. 2 (TP-2) are covered by artificial fill deposits (Qaf). In Test Pit No. 1 (TP-1 ), the paralic deposits are underlain by a loose sand deposit which is commonly found between sedimentary layers of paralic deposits in the area. Test Pits Nos. 1 and 3 were capped by top soil at the ground surface. The general geologic conditions are depicted on cross-sections A-A' and B-B' enclosed on Plate A and Plate B, respectively. A brief description of the earth materials encountered on the site follows: • Artificial Fill (Qat) In Test Pit No. 2 approximately 1.5 feet of artificial was encountered between the top soil and the underlying paralic deposits. The fill material was dark brown in color and consisted of silty sand with numerous shells and shell fragments. The fill was in a loose and dry condition. • Top Soil (Qs) Top soil was encountered in Test Pit Nos. 1 through 3 to approximate depths of 2.0 feet, 0.5 feet, and 2.0 feet, respectively. The top soil is classified as dark brown, sandy silt in a dry and loose condition, and contained many roots. • Very Old Paralic Deposits, Unit 12 (Qvop12) Underlying the surficial materials, middle to early Pleistocene paralic deposits are present. The paralic deposits are composed of reddish-brown, silty medium and fine- grained sand that is in a slightly moist and moderately dense condition. COAST GEOTECHNICAL • Very Old Paralic Deposits, Sand (Qvopsand) JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 10 of27 In Test Pit No. I (TP-1 ), tan fine and medium-grained sand with little or no cohesion was encountered at a depth of 4.5 feet. The loose sand probably represent interfingering of sediments. 5. 3 Expansive Soil Based on our experience in the area and previous laboratory testing of selected samples, the fill deposits and the Very Old Paralic Deposits reflect expansion potentials in the very low range. 5. 4 Groundwater Conditions No evidence of perched or high groundwater tables were encountered to the depth explored. However, it should be noted that seepage problems can develop after completion of construction. These seepage problems most often result from drainage alterations, landscaping, and over-irrigation. In the event that seepage or saturated ground does occur, it has been our experience that they are most effectively handled on an individual basis. 6. GEOLOGIC HAZARDS 6.1 Faulting and Seismicity The subject site is located within the seismically active Southern California region, which is generally characterized by northwest trending, right-lateral strike-slip faults and fault zones. Several of these fault segments and zones are classified as active by the California Geologic Survey (Alquist-Priolo Earthquake Fault Zoning Act.) As a result, ground shaking is a potential hazard throughout the region. Based on a review of published geologic maps, no known faults traverse the site (Figure 6). Thus, ground surface rupture is not likely to occur as a result of an earthquake or seismic event. The nearest active fault to the site is the Rose Canyon Fault Zone (offshore), located approximately 5.7 miles COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 11 of27 west of the site. It should be noted that the Rose Canyon Fault is one of four main fault strands that make up the Newport-Inglewood/Rose Canyon (NIRC) fault system (Treiman, 1984). The four strands form a series of right-stepping en echelon faults situated along the Southern California coastline. A recent study by Sahakian et al. (2017) concluded that the geometry of the NIRC fault system may enable rupture along the entire length of the fault zone. The study also modeled several rupture scenarios in light of the newly defined geometry which suggest earthquake ruptures up to magnitudes (M) of 7.4 are possible along the NIRC system. While the models are intriguing, the paper recommends further research and modeling on the NIRC fault geometry to improve our understanding of potential hazards and ground shaking along the Southern California coast. Therefore, the modeled rupture magnitude of M = 7.4 on the Rose Canyon Fault was not used for the recommendations for this investigation. Other nearby faults that may affect the site include the Newport-Inglewood fault (offshore), the Coronado Bank fault, and the Julian and Temecula segments of the Elsinore fault. The proximity of major faults to the site, and their estimated maximum earthquake magnitudes and peak site accelerations are enclosed on Table I and were determined by EQFAULT version 3.00 software (Blake, 2000). COAST GEOTECHNICAL Table 1: Principal Active Faults (Updated) FaultName Approximate Distance from site (mi) Rose Canyon (offshore) 6.0 Newport-Inglewood (offshore) 6.6 Coronado Bank 21.9 Elsinore (Temecula) 23.4 Elsinore (Julian) 23.5 Elsinore (Glen Ivy) 33.7 Palos Verdes 36.9 Earthquake Valley 42.8 San Jacinto (Anza) 46.0 JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 12 of27 Max.imwnEQ Peak Site Magnitude (Mmax) Accel. (g) 6.9 0.406 6.9 0.383 7.4 0.173 6.8 0.104 7.1 0.129 6.8 0.066 7.1 0.074 6.5 0.038 7.2 0.060 The Rose Canyon Fault is capable of generating a magnitude earthquake which would cause strong ground motions at the subject site. Further analysis on seismicity and the site specific seismic parameters are discussed in the Recommendations chapter of this report. 6.2 Landslide Potential A landslide is the displacement of a mass of rock, debris, or earth down a slope caused by topographic, geological, geotechnical and/or subsurface water conditions. Potential landslide hazards for the site were assessed using the review of published geologic and topographic maps for the area. According to the Landslide Hazards map, Oceanside-San Luis Rey (Tan and Giffen, 1995), the site is located within Susceptibility Area 3-1 where slopes are generally susceptible. Most slopes in this area do not contain landslide deposits, but they can be subject to failure if they are adversely modified. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 13 of27 Owing to the gently sloping topography at the site, the potential for landslide failure at the subject site is considered low. 6. 3 Liquefaction Potential Liquefaction is a process by which a sand mass loses its shearing strength completely and flows. The temporary transformation of the material into a fluid mass is often associated with ground motion resulting from an earthquake, and high groundwater conditions. Owing to the moderately dense nature of the Very Old Paralic Deposits and anticipated depth of groundwater seismically-induced liquefaction and soil instability is considered low. 7. CONCLUSIONS Based on the results from our evaluation of the site, construction of the proposed structures is feasible, provided the recommendations within this report are incorporated in the design and construction of the project. The following geotechnical considerations for the project site include: • No adverse geotechnical conditions which would preclude development for the site as proposed were observed during the course of this study. • Only minor clearing/grading, less than 50 cubic yards is proposed for the development of the proposed guest house and garage. • The proposed guest house and garage will be constructed on sloping terrain and supported on cast in-place, drilled piles and grade beams. Sands with little or no cohesion were encountered in Exploratory Test Pit No. 1. Some degree of caving should be anticipated during pile drilling in these deposits. Casing, sonotubing, or other methods of stabilization of loose sands will be necessary. COAST GEOTECHNICAL JOHN AND PRJSCILLA GEESBREGHT W.O. P-674617 Page 14 of27 • Disturbed soils resulting from the demolition of structures and utility lines should be removed and replaced as properly compacted fill. • Our experience with this type of lot development and geotechnical conditions suggest that varying degrees of seepage can develop after construction. Post-construction seepage and/or saturated ground conditions can adversely affect foundations and concrete flatwork. Therefore, special consideration should be provided for subsurface drainage during the design and construction phases. 8. RECOMMENDATIONS 8. I Temporary Slopes and Excavation Characteristics Temporary excavation, which expose fill and deposits, should be trimmed to a gradient of 1: 1 (horizontal to vertical) or less depending upon conditions encountered during grading. Paralic Deposits may be excavated to a vertical height of 4.0 feet. The temporary slope recommendations assume no surcharges are located or will be placed along the top of the slope within a horizontal distance equal to one half the height of the slope. The Paralic Deposits are dense below the weathered zone. However, based on our experience in the area, the deposits are rippable with conventional heavy moving equipment in good working order. 8.2 Drilled Cast-In-Place Piles Cast in-place piles should be a minimum of2.0 feet in diameter and founded a minimum of7.0 feet into competent old paralic deposits. Where sands with little or no cohesion are encountered under the reddish-brown paralic deposits, casing the lower portion of the piles may be necessary during drilling. A minimum clear space of 5.0 lateral feet should be maintained between piles. The piles should be designed to resist a downslope creep force of 400 pounds per foot, in the uphill side of the pile, per foot of depth of fill and soil penetrated. The point of fixity should be considered 1.0 foot below the soil/fill contact. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 15 of27 For design purposes, a net allowable skin friction value of 600 pounds per square foot may be used for piles founded a minimum of 7.0 feet into competent old paralic deposits. The weight of the pile may be assumed to be assumed to be supported by end bearing. The net allowable pile capacity increase should be limited to a maximum of 20 times pile diameter. Piles should be tied in two directions by grade beams. Grade beams should be a minimum of 24 inches wide by 18 inches deep. A minimum 3000 psi (fc) concrete should be considered for piles and grade beam design. The base of all drilled piles should be cleared of all loose material. This may be accomplished by a special clean out tool utilized at the completion of drilling of each pile. All piles should be observed by an engineering geologist at the time of drilling. 8.3 Foundations The following design parameters are based on footings founded into competent old paralic deposits. Footings, where necessary, for the proposed structure should be a minimum of 12 inches and 15 inches wide and founded a minimum of 12 inches and 18 inches into competent paralic deposits at the time of foundation construction for single-story and two-story structures, respectively. A 12 inch by 12 inch grade beam or footing should be placed across the garage opening. Footings should be reinforced with a minimum of four No. 4 bars, two along the top of the footing and two along the base. Where parallel wall footings occur, the upper footing should be deepened below a 45 degree plane projected up from the base of the lower footing, or the lower wall should be designed for the additional surcharge load from the upper wall. Footing recommendations provided herein are based upon underlying soil conditions and are not intended to be in lieu of the project structural engineer's design. COAST GEOTECHNlCAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 16 of27 The base of footings should be maintained a minimum horizontal distance of 10 lateral feet to the face of the nearest slope. For design purposes, an allowable bearing value of 1700 pounds per square foot and 2000 pounds per square foot may be used for foundations at the recommended footing depths for single and two story structures, respectively. For footings deeper than 18 inches, the bearing value may be increased by 250 pounds per square foot for each additional 6.0 inches of embedment to a maximum of3000 pounds per square foot. The bearing value may be increased by one-third for the short durations of loading, which includes the effects of wind and seismic forces. The bearing value indicated above is for the total dead and frequently applied live loads. This value may be increased by 33 percent for short durations of loading, including the effects of wind and seismic forces. 8. 4 Slabs on Grade (Interior and Exterior) Slab on grade, if necessary, should be a minimum of 5.0 inches thick and reinforced in both directions with No. 4 bars placed 18 inches on center in both directions. Exterior slabs on grade should be a minimum of 4.0 inches thick and reinforced with No. 3 placed 18 inches on center in both directions. The slab should be underlain by a minimum 2.0-inch coarse sand blanket (S.E. greater than 30). Where moisture sensitive floors are used, a minimum 10.0-mil Visqueen, Stego, or equivalent moisture barrier should be placed over the sand blanket and covered by an additional two inches of sand (S.E. greater than 30). Utility trenches underlying the slab may be backfilled with on-site materials, compacted to a minimum of 90 percent of the laboratory maximum dry density. Slabs including exterior concrete flatwork should be reinforced as indicated above the provided with saw cuts/expansion joints, as recommended by the project structural engineer. All slabs should be COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 17 of27 cast over dense compacted subgrades. Our experience indicates that the use of reinforcement in slabs and foundations can reduce the potential for drying and shrinkage cracking. However, some minor cracking is considered normal and should be expected as the concrete cures. Moisture barriers can retard, but not eliminate moisture vapor movement from the underlying soils up through the slab. 8.5 Lateral Resistance Resistance to lateral load may be provided by friction acting at the base foundations and by passive earth pressure. A coefficient of friction of 0.35 may be used with dead-load forces. Design passive earth resistance may be calculated from a lateral pressure corresponding to an equivalent fluid density of 300 pounds per cubic foot with a maximum of 2500 pounds per square foot. 8.6 Retaining Walls Cantilever walls (yielding) retaining nonexpansive granular soils may be designed for an active-equivalent fluid pressure of 3 7 pounds per cubic foot for a level surcharge and 45 pounds per cubic foot for a sloping surcharge. Restrained walls ( nonyielding) should be designed for an "at-rest" equivalent fluid pressure of 60 pounds per cubic foot. Wall footings should be designed in accordance with the foundation design recommendations. All retaining walls should be provided with adequate backdrainage system. A geocomposite blanket drain such as Miradrain 6000 or equivalent is recommended behind walls. The soil parameters assume a level nonexpansive select granular backfill compacted to a minimum of 90 percent of the laboratory maximum dry density. 8. 7 Dynamic (Seismic) Lateral Earth Pressures For proposed restrained walls (non-yielding), potential seismic loading should be considered. For smooth rigid walls, Wood (1973) expressed the dynamic thrust in the following form: ~Pe = kh YH2 (nonyielding) COAST GEOTECHNJCAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 18 of27 where kh is ½ peak ground acceleration equal to 50 percent of the design spectral response acceleration coefficient (Sds) divided by 2.5 per C.B.C. (2007), Y is equal to the unit weight of backfill, and H is equal to the height of the wall. The pressure diagram for this dynamic component can be approximated as an inverted trapezoid with stress decreasing with depth. The point of application of the dynamic thrust is at a height of 0.6 above the base of the wall. The magnitude of the resultant is: .!\Pe = 18.9 H2 (nonyielding) This dynamic component should be added to the at-rest static pressure for seismic loading conditions. For cantilever walls (yielding), Seed and Whitman (1970) developed the dynamic thrust as: .!\Pe = 3/8 kh YH2 (yielding) The pressure diagram for this dynamic component can be approximated as an inverted trapezoid with stress decreasing with depth and the resultant at a height of 0.6 above the base of the wall. The magnitude of the resultant is: .!\Pe = 7 .1 H2 (yielding) This dynamic component should be added to the static pressure for seismic loading conditions. COAST GEOTECHNICAL 8.8 Settlement Characteristics JOHN AND PRISCILLA GEESBREG HT W.0. P-674617 Page 19 of27 Estimated total and differential settlement over a horizontal distance of 30 feet is expected to be on the order of 1.0 inch and¾ inch, respectively. It should also be noted that long term secondary settlement due to irrigation and loads imposed by structures is anticipated to be ¼ inch. 8. 9 Seismic Considerations Although the likelihood of ground rupture on the site is remote, the property will be exposed to moderate to high levels of ground motion resulting from the release of energy should an earthquake occur along the numerous known and unknown faults in the region. The Rose Canyon (offshore) Fault Zone located approximately 5.7 miles west of the property is the nearest known active fault, and is considered the design fault for the site. In addition to the Rose Canyon fault, several other active faults may affect the subject site. Seismic design parameters were determined as part of this investigation in accordance with Chapter 16, Section 1613 of the 2016 California Building Code (CBC) and ASCE 7-10 Standard using the web-based United States Geological Survey (USGS) Seismic Design Tool. The generated results for the parameters are presented on Table 2. COAST GEOTECHNICAL Table 2: Seismic Design Parameters Factors Site Class Seismic Design Category Site Coefficient, Fa Site Coefficient, Fv Mapped Short Period Spectral Acceleration, Ss Mapped One-Period Spectral Acceleration, S, JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 20 of27 Values D D 1.056 1.573 I.I 10 0.427 Short Period Spectral Acceleration Adjusted for Site Class, SMs 1.172 One-Second Period Spectral Acceleration Adjusted for Site, SM, 0.671 Design Short Period Spectral Acceleration, S0s 0.781 Design One-Second Period Spectral Acceleration, S0 1 0.447 8. IO Preliminary Pavement Design The following preliminary pavement section is recommended for proposed driveways: • 4.0 inches of asphaltic concrete on • 6.0 inches of select base (Class 2) on • 12 inches of compacted subgrade soils or • 5.5 inches of concrete on • 12 inches of compacted subgrade soils Subgrade soils should be compacted to the thickness indicated in the structural section and left in a condition to receive base materials. Class 2 base materials should have a minimum R-value of 78 and a minimum sand equivalent of 30. Subgrade soils and base materials should be compacted to a minimum of 95 percent of their laboratory maximum dry density. Concrete should be reinforced with No. 3 bars placed 18 inches on center in both directions. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 21 of27 The pavement section should be protected from water sources. Migration of water into subgrade deposits and base materials could result in pavement failure. Additional recommendations will be necessary is permeable pavers are proposed. 8.11 Utility Trench We recommend that all utilities be bedded in clean sand to at least one foot above the top of the conduit. The bedding should be flooded in place to fill all the voids around the conduit. Imported or on-site granular material compacted to at least 90 percent relative compaction may be utilized for backfill above the bedding. The invert of subsurface utility excavations paralleling footings should be located above the zone of influence of these adjacent footings. This zone of influence is defined as the area below a 45 degree plane projected down from the nearest bottom edge of an adjacent footing. This can be accomplished by either deepening the footing, raising the invert elevation of the utility, or moving the utility or the footing away from one another. 8.12 Drainage Specific drainage patterns should be designated by the project architect or engineer. However, in general, pad water should be directed away from foundations and around the structure to the street. Roof water should be collected and conducted to the street via non-erodible devices. Pad water should not be allowed to pond. Vegetation adjacent to foundations should be avoided. If vegetation in these areas is desired, sealed planter boxes or drought resistant plants should be considered. Other alternative may be available, however, the intent is to reduce moisture from migrating into foundation subsoils. Irrigation should be limited to that amount necessary to sustain plant life. All drainage systems should be inspected and cleaned annually, prior to winter rains. COAST GEOTECHNICAL 8.13 Permeable Interlocking Concrete Pavers (P!CP) JOHN AND PRJSCILLA GEESBREGHT W.O. P-674617 Page 22 of27 Permeable Interlocking Concrete Pavers (PICP), if proposed, should consider several design aspects. Foundations adjacent to or in close proximity to PICP should be protected by an impervious membrane extending a minimum of3.0 lateral feet from the foundation under the pavement section. The intent is to reduce lateral migration of infiltrated drainage and potential impaction on footings. However, this approach is considered less desirable from a geotechnical viewpoint than lining the section with an impervious liner. Pavement underdrains are recommended and should be incorporated in the design for proper collection and disposal of filtrated storm water as indicated on Plate C. If subdrains are not allowed for storm water infiltration by reviewing agencies, the long term effects of infiltrated water on structural foundations and slabs cannot be predicted with any degree of certainty. PICP pavement structural section (Driveways) should consist of31/s inch PICP, over a minimum of 2.0 inches of ASTM No. 8 bedding course/choke stone, over a minimum of 8.0 inches of ASTMNo. 57 stone base course, over a minimum of 12 inches of 95 percent compacted subgrade. Bedding course/choke stone and base course stone should also be well compacted, consolidated, and interlocked (avoid crushing the underdrain pipes) with heavy construction equipment. ASTM No. 8, No. 9 or No. 89 should be used for joint materials, depending on the joint size and per manufacturer recommendations. The above stone base section may be reduced from 12 inches to a minimum of 6.0 inches for walkways and patios, if desired. The gradational requirements are summarized on Table 3. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 23 of27 Table 3: Gradational Requirements for ASMT No. 57, No. 8, No. 89, and No. 9 Sieve Percent Passing Size No. 57 No. 8 No. 89 No.9 1 ½" 100 l" 95 to 100 ½" 25 to 60 100 100 3/a" 85 to 100 90 to 100 100 No.4 0 to 10 10 to 30 20 to 55 85 to 100 No. 8 0 to 5 0 to 10 5 to 30 10 to 40 No. 16 0 to 5 0 to 10 0 to 10 No. 50 0 to 5 0 to 5 8. I 4 Geotechnical Observations Structural footing excavations should be observed by a representative of this firm prior to the placement of steel and forms. All fill should be placed while a representative of the geotechnical engineering is present to observe and test. 8. I 5 Plan Review A copy of the final plans should be submitted to this office for review prior to the initiation of constructions. Additional recommendations may be necessary at that time. 9. LIMITATIONS This report is presented with the provision that it is the responsibility of the owner or the owner's representative to bring the information and recommendations given herein to the attention of the project's architects and/or engineers so that they may be incorporated into the plans. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 24 of27 If conditions encountered during construction appear to differ from those described in this report, our office should be notified so that we may consider whether modifications are needed. No responsibility for construction compliance with design concepts, specifications, or recommendations given in this report is assumed unless on-site review is performed during the course of construction. The subsurface conditions, excavation characteristics, and geologic structure described herein are based on individual exploratory excavations made on the subject property. The subsurface conditions, excavation characteristics, and geologic structures discussed should in no way be construed to reflect any variations which may occur among the exploratory excavations. Please note that fluctuations in the level of groundwater may occur due to variations in rainfall, temperature, and other factors not evident at the time measurements were made and reported herein. Coast Geotechnical assumes no responsibility for variations which may occur across the sire. The conclusions and recommendations of this report apply as of the current date. In time, however, changes can occur on a property whether caused by acts of man or nature on this or adjoining properties. Additionally, changes in professional standards may be brought about by legislation or the expansion ofknowledge. Consequently, the conclusions and recommendations of this report may be rendered wholly or partially invalid by event beyond our control. This report is therefore subject to review and should not be relied upon after the passage of two years. The professionaljudgements presented herein are founded partly on our assessment of the technical data gathered, partly on our understanding of the proposed construction, and partly on our general experience in the geotechnical field. However, in no respect do we guarantee the outcome of the project. COAST GEOTECHNICAL JOHN AND PRISCILLA GEESBREGHT W .O. P-674617 Page 25 of27 This study has been provided solely for the benefit of the client, and is in no way intended to benefit or extend any right or interest to any third party. This report is not to be used on other projects or extensions to this project except by agreement in writing with Coast Geotechnical. COAST GEOTECHNICAL REFERENCES JOHN AND PRISCILLA GEESBREGHT W.O. P-674617 Page 26 of27 Blake, T. F. (2000). EQFAULT: A Computer Program for the Deterministic Estimation of Peak Acceleration using Three-Dimensional California Faults as Earthquake Sources, Version 3.0, Thomas F. Blake Computer Services and Software, Thousand Oaks, CA. California Building Standards Commission. (January 1, 2016). 2016 California Building Code, California Code of Regulations. California Geologic Survey, (1994), Fault Activity Map of California, Map Scale 1"=750,00'. Kennedy, M. P., and Tan, S. S. (2008). California Geological Survey, Regional Geologic Map No. 2, 1: 100,000 scale. Sahakian, V ., et al.(2017). Seismic Constraints on the Architecture of the Newport-Inglewood/Rose Canyon Fault: Implications for the Length and Magnitude of Future Earthquake Ruptures. American Geophysical Union (In progress). DOI: 10.1002/2016JB013467 Sampo Engineering. (2017). Topographic Plat, 4056 Skyline Road, Carlsbad, California. Scale l" = 10'. Seed, H.B., and Whitman, R.V. (1970). Design of earth retaining structures for dynamic loads. In Proceedings of the ASCE Special Conference on Lateral Stresses, Ground Displacement and Earth Retaining Structure, Ithaca, N.Y., pp. 103-147. Tan, S. S., and Giffen, D. G. (1995). Landslide Hazards in the Northern Part of the San Diego Metropolitan Area, San Diego County, California, OFR 95-04, Plate A. COAST GEOTECHNICAL REFERENCES (continued) JOHN AND PRJSCILLA GEESBREGHT W.O. P-674617 Page 27 of27 Treiman, J. A. (1984). The Rose Canyon Fault Zone: A Review and Analysis, California Division of Mines and Geology, Fault Evaluation Report 216. Wood, J.H. (1973). Earthquake-induced soil pressures on structures. Ph.D. thesis, the California Institute of Technology, Pasadena, Calif. USGS, U.S. Seismic Design Maps, Scale = Variable. https://earthquake.usgs.gov/designmaps/us/application.php APPENDIX A Figure 1 Stte Location COAST GEOTECHNICAL 5931 SEA LION PLACE. SUITE 109 CARLSBAD, CA 92010 4056 SKYLINE ROAD, CARLSBAD, CA 92008 T.:➔• .• , .. . ' .,-·~, . . :J ~ '.,, Legend 4056 Skyine Rd P-674617 'I Ct•JITV \' .\P Ill)' 'lll ltlJ" -0. ,(~· = ll "»c It t:11< ,wr "x., ' "" 1~ 9 " 4056 S XID •pJ;J '1'161 I ~ ><JIU Site Plan line Road Carlsbad ,, •MJ ~ ,,., & .. ~ I I l .., I l ··"" )!JffJ !f4J ~ (I( ,<If($ /10 • NSD I ><Jftl '1 ___ .:._.,a, I I I I I I I I I I I I 2 ;.JIIJ I! ... -,.u ><Jjlr I ' ' ,. (M m ,. ' I I I , ... ~, I I I I I ,' ,.., I , I , ., , / I I • .. ,.., al -~ I ' I I I I I I I I I I ; I ,c/!Uf I I I I I I ' :f / t I ,me I I I I I I I I I I I I I 1 I I • ,,.OJ RI I I I I I ' \ --------.. • • • > ' ----------.19(, o; ~ I: ~---------"'''i _.,,.,a,r ________ __2!!J'ITJII -----__J_ _ --... ---.-\ Figure 2 P-674617 I I I I \ \ \ \ \ B' Project: Prellm Geotech lnvestigatlo h Log of Boring TP-1 Sheet 1 of 1 Coast GeottcMCal P . t L t· 4051 Skyline Road, ro1ec oca ,on: cartstiad, cA uooa Project Number: P.e14111 OnJI' ~ Excavation ~ig CAT Mini Excavator Groundwamr Level and Oate Measured No Borehole Backfill I C .g ~ .J! w 298- 297- 208- m - m - 200- 8. :::, Cl> >, :!. I- .5! i ~ ~ IQ IJ) 0 1- 2- 3- a- 8- 9- .8 E :::, z ! E IQ 1/) Cl> Q. ~ ;; ·c Cl> j SM SP ! 1 Q. (3 Logged By E.W. OriUBlt Size/Type Onlhng Contrac:tor LFukuda Sampling Mathod(I) LocabOn Rear yard-South MATERIAL DESCRIPTION 51131 Sea uon "'-· SI.lie 109 caml>ad, CA 92010 (858) 7ss.8622 Chedled By W.B. Total Depth ot Borehole 8·5 ApprO)um8te 298 Surleee Elev81ion Hammer Data REMARKS AND OTHER TESTS Top Soil (Os)• Oarit brown, sandy silt, loose and dry. Contain many roots. -- Very Old Parallc Deposits (Qvopas) • Reddish-brown. mediu~ _ fine-grained sand, silty, lightly moist, moderately dense - - -- •• ~ Loose sand (Qvop(sand))-Tan, medium and fine-grained san ~.silty.dry, ~:• ".• loose. lnterpretted as interfingered with Oop •U--... ·.~ •:·-:, i.•:~~ Caving after drove sample, -=\, 1ai•:~9!~ l:•:r ..... -: ,:·•:, ... •.~ ,.·.•,-" .. i-•:-~ !, .... .. -::: ,: .. ·, 1--.. • :: ,:· .. ·, Bottomat8.5' Sllght caving No Groundwater - - - - 288-10-'---L--.L..-1---L-...L.--------------------...L----------~ Figure 3 Project: Prellm Geotech lnvestlgatic n Log of Boring TP-2 Sheet 1 of 2 Coasl Geotec:tlnical P ·ect L t· 40M SkyllM Road, roJ oca ion: cartablld, CA ezooa Project Number: P-e14e11 Drilling Excavation Method ~;!Rig CAT Mini Excavator Groundwater Level end Date MeaMlfed No Borehole 8eclcfill ~ ~ C .2 I 302- 301- 300- 299- 298- 296- 2115- 293- ! i Jl £i a. E 0. c!: CII cn 0 1- 2- 3- 6- 7- 8- II- .8 E :> z -! E .,, en t ~ "iii ·c G> .; ::i:; Fill SM 8' ..J ~ a. a ~ ~ Logged By E.W. Drill Bit Size/Type Dnll1ng ContractDr L. Fukuda Sampling Melhod(s) Location Rear yard-North MATERIAL DESCRIPTION FIii (Oaf) -Dark brown sandy sill with shell hash - 5931 SN Lien Place. 5'a1il 109 CIIIISbtcl. CA 92010 (858) 765-a522 Chedled By W.B. Total Depth 10 5 ot Boreholo • Approximate 302 Swfeoe Etevabon Hammef Data - REMARKS AND OTHER TESTS Very Old Paralic Deposits (Qvop12) -Reddish-brown, medlun fine-grained sand, silty, moist, moderately dense -- - -- -- - - -- 2112-,o_.___, _ __,'--.....L----LMlll.----------------------'L-----------J Figure 4a Project: Prellm Geotech lnvestlgatic n Log of Boring TP-2 CoaSI Gtolec:Mlcal p . ect L f 4056 SleyllH Road, 6931 Sea Lion Pleel. Sule 109 roJ oca ion: c■rtsbad, CA 1200& Sheet 2 of 2 Carlsbad. CA 92010 (858) 75s-8622 Project Number: P.e1.-11 ~ 8. .8 8. ~ E 8' I ~ ::I ~ C z ...I .g i JI ~ .!l iii -5 Q. ·c .c CII Q. 1 a. E -; I! REMARKS AND OTHER TESTS ~ Ill Ill MATERIAL DESCRIPTION w U) U) ~ " m -10 SM [Ul].J Very Old Paralic Deposits (Qvop12) -Reddish-brown, mediur , fine-grained sand, silty, moist, moderately dense ) Bottom at 10.5' -. . No groundwater -Some caving . 287-16-.... -. . . -1-- 282-20-..... - - -. - 2n-2S-,... - . 1-- - 272-JO---. . - . - 267-35--- . -. 261-40---- . -. . . 257-45 Figure 4b Project: Prellm Geotech lnvestlgatic n Log of Boring TP-3 Coast GeotechWCal p . eci L f 4056 Skyllnt Road, 5931 S.. U0n PIIICAI, Suite 1~ roJ oca ion: c111aud, CA 92008 Sheet 1 of 1 C8IISDIO CA 92010 (858)7~ Project Number: P-47-4617 Oate(s) 6119/17 Orilled Logged By E.W. che<:ked ey w.e. OnUlng Oril1Bit Total Depth MethOd Excavation SizefType of Borehole 8•5 ~:~Rig CAT Mini Excavator Orilling Contractor L. Fukuda Approximate Surface Elevation 308 Groundwlllel Level Samphng Hammer and O.te Measured No MethOd(s) Data Borehole Locauon Rear yard-North Bacilfill ! II jl 8. Q. E gi ai ~ ~ ~ C ~ z ~ 0 Ji II cii .Si -= :S 15. ·c .s= ~ 0. ... e e .!! ... di ~ .. .. .. i5 MATERIAL DESCRIPTION REMARKS AND OTHER TESTS Cl) (/) ::i: 308-0 Top Soil (Os) -Dark brown, sandy silt, loose and dry. Contain many roots. ·Damaged irrigation line (repaired onsite) 307-,--- 308-2-SM Very Old Paralic Deposits (Ovop)12 -Reddish-brown, mediur fine-grained sand, silty, moist, dense 305-3--- JOI-4-.... - 303-5-.... - 302-8-.... - 301-7-.... - 300-8--- Bottom at 8.5' m -9--No caving No groundwater - 2118-10 Figure 5 Project Key to Log of Boring Co.I! Geolec:tncal 5931 Sea uon Place, &>le 109 Project Location: Sheet 1 of 1 c.tlabad, CA 112010 Project Number: (858) 75s-a622 8 r: (I) ~ j .; ! ·.;; ! ~ ~ E 41 .s :, a: r: ~ z ii .2 ~ Ji! iii (J j .t::. Q. ·r: :c 0.. E E ~ Q. ~ ~ ell i .2 (I) I! MATERIAL DESCRIPTION REMARKS ANO OTHER TESTS w (/) (/) .0 ~ 0 w l1J ~ l.iJ Iii ~ llJ tru Ii.I COLUMN DESCRIPTIONS i Elevation (feet): Elevation (MSL, feet). [ii Material Type: Type of material encountered. Depth (feet): Depth In feet below the ground surface. [!] Graphic Log: Graphic depiction of the subsurface material Sample Type: Type of soil sample collected at the depth Interval encountered. shown. {!) MATERIAL DESCRIPTION: Description of material encountered. [!] Sample Number: Sample identification number. May Include consistency. moisture, color. and other descriptive [!] Sampling Resistance. blowsMt: Number of blows to advance driven text. sampler one foot (or distance shown) beyond seating interval I!] REMARKS AND OTHER TESTS: Comments and observations using the hammer identified on the boring log. regarding drilling or sampling made by driller or field personnel. FIELD AND LABORATORY TEST ABBREVIATIONS CHEM: Chemical tests to assess corrosivity COMP: Compaction test CONS: One-<limensional consolidation test LL: Liquid Limit, percent Pl: Plasticity Index, percent SA: Sieve analysis (percent passing No. 200 Sieve) UC: Unconfined compressive strength test. Ou. in ksf WA: Wash sieve (percent passing No. 200 Sieve) MATERIAL GRAPHIC SYMBOLS II Silty SAND (SM) ···~ :•:,• Poorty graded SAND (SP) ·- TYPICAL SAMPLER GRAPHIC SYMBOLS I Auger sampler I Bulk Sample 1'1 3-inch-OD California wl ~ brass rings GENERAL NOTES ra CME Sampler rn Grab Sample 12.5-lnch-00 Modified Catifomia w/ brass liners OTHER GRAPHIC SYMBOLS ~ Pitcher Sample • Water level (at time of dnlllng, ATO) • Wal« Ulllel (after waiting) ~ 2-inch-OD unlined split ~ spoon (SPT) l i\iJ Shelby Tube (Thin-walled, Minor c:tlange ,n material p,openles within a stratum \61 fixed head) lnfetred/gradatlonal contact between strata -, -Ouened contact between atnlta 1: SoU c:lasalfiealions are baaed on the Unified Soll Classification System Oeaoiptions and st1111tum ltnes .,. interpretive, and ac:tual t1tholog,c changes mav be gradual Field descriptions mav hive been modified to reflect reaulta of l■b tests. 2. Oesalpllons on thne logs apply ontv et 11111 speaflc boring locebons encl at Ille lime the borings were lldvenc:eo. They are not wa11&nted 10 1111 representative of subsurlac,e condlbons at other toc:abOns or bmlls, Key to Figs 3-5 250 200 150 100 50 0 -50 -100 100 150 Legend "\ Active Faults San Diego Fault Map 200 250 Distance 300 350 400 Figure 6 P-674617 APPENDIXB LABO RA TORY TESTING AND RESULTS Earth materials encountered in the exploratory test pits were closely examined and sampled for laboratory testing. The laboratory tests were performed in accordance with the generally accepted American Society for Testing and Materials (ASTM) test methods or suggested procedures. Classification: The field classification was verified through laboratory examination, in accordance with the Unified Soil Classification System. The final classification is shown on the enclosed Exploratory Logs in Appendix A. Grain Size Distribution: The grain size distribution of selected soil samples was determined in accordance with ASTM D6913-04. The test result is presented on Table 4. TABLE4 Sieve Size 1" ¾" ½" #4 #10 #20 #40 #100 #200 Location Soil Type Percentage Passing TP-1 @ 5'+ l 100 100 100 100 100 99 75 12 7 TP-1 @ 2-4' 2 100 100 100 100 100 99 70 16 1 I Expansion Index Test: An Expansion Test was performed on the selected sample. The test procedure were conducted in accordance with the Uniform Building Code, Standard No. 29-2 and AMST 0-4829. The classification of expansive soil, based on the expansion index, are as indicated in Table 29-C of the Uniform Building Code. The test result is presented on Table 5. TABLES Location Soil Expansion Degree of Uncorrected Corrected EI for Type Reading Saturation Expansion Index (El) 50% Saturation TP-1 @ 2-4' 2 0.000 43.5 0 0 Maximum Dey Density and Optimum Moisture Content: The maximum dry density and optimum moisture content were detennined for selected samples of earth materials taken from the site. The laboratory standard tests were in accordance with ASTM D-1557-12. The test result is presented on Table 6. TABLE6 Location Soil Type Maximum Dry Optimum Moisture Density (ym-pcf) Content (coopt-%) TP-1 @ 5'+ 1 110 9.5 TP-1 @ 2-4' 2 120.5 11.5 Moisture/Density: The field moisture content and dry unit weight were determined for each of the undisturbed soil samples. Test procedures were conducted in accordance with ASTM D7263-09 (Method A). This information is useful in providing a gross picture of the soil consistency or variation among exploratory excavation. The field moisture content was determined as a percentage of the dry unit weight. The dry unit weight was detennined in pounds per cubic foot (pct). The test results are presented on Table 7. TABLE 7 Field Field Dry Max. Dry Degree of Sample Soil In-place Relative Moisture Density Density Saturation Location Type Compaction(%) Content(%) ('yd-pct) (ym-pcf) (%) TP-2@ l" 2 7.2 108 116 90 35 TP-1 @4' 2 5.3 108 114 90 25 TP-2 @4' 2 3.0 116 120 97 18 TP-2@6' 2 4.8 78 82 65 11 TP-2 @ 2 7.5 98 106 82 28 10.5'' TP-3@2' 2 2.9 113 117 94 16 TP-3 @5- 2 7.3 112 120 93 39 6' Sulfate Test: A sulfate test was perfonned on a selected sample in accordance with California Test Method (CTM) 417. The test result is presented on Table 8. TABLES Sample ID Sulfate Content (mg/kg) Sulfate Content (% by wgt) TP-1 @ 4 ft. 10 0.001 Shear Test: Shear tests were perfonned in a strain-control type direct shear machine. The laboratory standard tests were in accordance with ASTM D3080. The rate of defonnation was approximately 0.025 inches per minute. Each sample was sheared under varying confining loads in order to determine the Coulomb shear strength parameters, cohesion. and angle of internal friction. Samples were tested in a saturated condition. Coast Geotechnlcal DIRECT SHEAR ASTM D 3080 Project: P-674617 Geeabreght. Sample ID: TP-2@6 ft. Soil Description: (SM) Brown, Lightly Cemented, Silly Fine to Medium Sand Displacement Rate: 0.050 in/m Box Gap: 0.025 in Max Data: -------Remold Target Data: -% = 103.4 pcf -%MC(-No.10) 2.65 Gs(auumed) *As Received Mc: 0.6 Adjusted Mc: -% .'"After Shear Mc: -% ■ Undisturbed □ Remolded SHEAR RECORD: Displacement (in): 0.020 0.040 0.060 0.080 0.100 0.120 0.140 0.160 0.180 0.200 0.220 0.240 0.260 0.280 0.300 0.320 0.340 0.360 0.380 0.400 0.420 0.440 0.460 0.480 . 0.500 "SHEAR STRESS: Divisions Test 1: 227 Test 2: 135 Test 3: 74 "Elds11ng Gradation for l.lldlstult>ed apecimens. -No.10 fraction for ,.molded specimens -,.at 1 Spec:lmen (HlghNl Normal Stress) Test 1 Test2 Test 3 Prov. Ring Vert Dial Prov. Ring Vert. Dial Prov. Ring Vert. Dial 161 98 92 101 50 101 192 101 119 104 66 105 216 105 134 109 72 111 223 108 135 113 74 114 227 109 128 115 71 117 226 110 117 116 63 119 204 111 107 117 190 112 175 112 Pounds psf 67.78 1988 3000 .. ,_ ~ .+--r I t ,, 40.03 1174 21.85 641 2500 +-1--,--~-' -... -·-,.,, i . ·-'--...--k-L.. L-'--l..,,t 1 ... -L. NORMAL STRESS (psf): it IJ' --k. -•-- PtOVlng~ SN: 8927 C11ibmed 30-August-18 Test 1: Test 2: Test 3: 2070 1035 517 40.6° 234 psf 500 0 ,__ -,_ ,__ -- . .,,. . ~ [7 0 .... ,__ : , Ill" 7. ,_ ....... -H ~r .. -.. ~ L.. --1 , .. ,._ --t -~ --I -t I-+--H 1000 2000 3000 Nonna! SINIU (psf) DIRECT SHEAR ASTM D 3080 Coast Geotechnical Project P-674617 Geesbreght, Sample ID: TP-2@ 10.5 ft. Soil Description: (SM) Brown, Lightly Cemented, Silty Fine to Medium Sand Displacement Rate: 0.050 in/m Box Gap: 0.025 in Max Data: -------Remold Target Data: -% = 98.3 pcf -%MC(-No.10) 2.65 Gs(assumed) *As Received Mc: 0.7 Adjusted Mc: -% .**After Shear Mc: -% ■ Undisturbed *Existing Gnidetlon fOf I.Wldi&turt>ed specimens, -No.10 fraction for remoldec:t specimens ••rest 1 Specimen (Highest Nom1al Suess) □ Remolded Test 1 Test2 Test3 SHEAR RECORD: Prov. Ring Vert. Dial Displacement (in): 0.020 148 101 0.040 177 103 0.060 201 106 0.080 212 109 0.100 215 110 0.120 215 110 0.140 204 111 0.160 183 111 0.180 162 111 0.200 0.220 0.240 0.260 0.280 0.300 0.320 0.340 0.360 0.380 0.400 0.420 0.440 0.460 0.480 0.500 •SHEAR STRESS: Divisions Pounds DSf Test 1: 215 64.19 1883 Test 2: 110 32.59 956 Test 3: 78 23.01 675 *PNJtValuN NORMAL STRESS (psf): PrOlling Ring SN:6927 Calibrated 30-August-16 Test 1: Test 2: Test 3: 2070 1035 517 38.5° 212 psf Prov. Ring 73 94 107 110 108 101 90 3000 2500 500 0 Vert. Dial Prov. Ring Vert. Dial 100 53 101 102 68 103 105 76 108 107 78 110 108 77 112 109 69 112 108 L-'-l . i ,_ ..... --_L_ ~ ,_ '--~ . --l · . :.a ~ -'--,__,._ 1 . -,,11' ,_ '---'---'--,_ L-'--bl" ,_ ·-'--·-f-.---L-~ ~ 1--- ~ l ,. II' +. h, -I.-.__ ...... I ... ~ ~ - 1 ~ l,-' l . I,. ---.J,. ~ ·- L-C. '-- I;' ----V, ~ ' ---- -l-i -- 0 1000 2000 3000 NonNII Strwss (psf) Design Maps Summary Report hups ://carthquakc.usgs.gov/cn I /dcsignmaps/us/summary. php?tcm pl ate= FI IIUSGS Design Maps Summary Report User-Specified Input Report Title P-674617 Wed July 5, 2017 23:12:52 UTC Building Code Reference Document ASCE 7-10 Standard (which utllzes USGS hazard data avallabfe In 2008) Site Coordinates 33.1556°N, 117.3193°W Site Soil Classification Site Class D -"Stiff Soll" Risk Category I/II/III USGS-Provlded Output S5 = 1.110 g S1 = 0.427 g SNS= 1.172 g ~1 = 0.671 g .. Sos= 0.781 g 501 = 0.447 9 Escondido• For Information on how the SS and 51 values above have been calculated from probabilistic (risk-targeted) and deterministic ground motions in the direction of maximum horizontal response, please return to the application and select the "2009 NEHRP" building code reference document. V ~ &. n "' For PGA.,, Tl, C11s, and Cai values, please vJew the detailed report. Oas t;'l Rcs;io-1:.r: Spec:• .J'" 1•-,AI{ ... ) Alhough this tnforlT\iltlon Is a product of the U.S. Geological survey, we provide no warranty, expressed or Implied, as to the accuracy or the data contained therein. Tl'IIS tool ls not a substitute for technlCal subject-matter knowledge. 7/5/17, 4:13 PM Design Maps Detailed Report https://ea11hquake.usgs.gov/cn 1/designmaps/us/report.php?tcmplate=mi f6 IIUSGS Design Maps Detailed Report ASCE 7-10 Standard (33.1556°N, 117.3193°W) Site Class D -"Stiff Soll", Risk category I/II/III Section 11.4.1 -Mapped Acceleration Parameters Note: Ground motion values provided below are for the direction of maximum horizontal spectral response acceleration. They have been converted from corresponding geometric mean ground motions computed by the USGS by applying factors of 1.1 (to obtain S5) and 1.3 (to obtain 51). Maps In the 2010 ASCE-7 Standard are provided for Site Class 8. Adjustments for other Site Classes are made, as needed, In Section 11.4.3. From Figure 22-1 t11 Ss = 1.110 g From Figure 22-2 121 51 = 0.427 g Section 11.4.2 -Site Class The authority having jurisdiction (not the USGS), site-specific geotechnlcal data, and/or the default has classified the site as Site Class D, based on the site soil properties In accordance with Chapter 20. Table 20.3-1 Site Classification Site Class A. Hard Rock B. Rock C. Very dense soil and soft. rock D. Stiff Soll E. Soft. clay soil F. Solis requiring site response analysts In accordance with Section 21.1 Vs >5,000 ft/s 2,500 to 5,000 ft/s 1,200 to 2,500 ft/s 600 to 1,200 ft./s Nor Nm N/A N/A >50 15 to so Su N/A N/A >2,000 psf 1,000 to 2,000 psf <600 ft./s <15 <1,000 psf Any profile with more than 10 ft of soil having the characteristics: • Plasticity Index Pl > 20, • Moisture content w ~ 40%, and • Undrained shear strength s. < 500 psf See Section 20.3. l For SI: lft/s = 0.3048 m/s llb/ft.t .. 0.0479 kN/m.t 7/5/17, ~:13 PM Oesign Maps Detailed Report hups://earthquakc.usgs.gov/cn 1/designmaps/uslrcport.php?tcmpl:ite=mi '6 Section 11.4.3 -Site Coefficients and Risk-Targeted Maximum Considered Earthquake (MCE ) Spectral Response Acceleration Parameters Site Class A B C D E F Site Class A B C D E F Table 11.4-1: Site Coefficient F, Mapped MCE II Spectral Response Acceleration Parameter at Short Period 55 S 0.25 S5 = 0.50 S5 = 0.75 Ss = 1.00 0.8 0.8 0.8 0.8 1.0 1.0 1.0 1.0 1.2 1.2 1.1 1.0 1.6 1.4 1.2 1.1 2.5 1.7 1.2 0.9 See Section 11.4.7 of ASCE 7 Note: Use straight-line Interpolation for intermediate values of 55 For Site Class= D and S. = 1,110 g, F0 = 1,056 Table 11.4-2: Site Coefficient F. 55 ~ 1.25 0.8 1.0 1.0 1.0 0.9 Mapped MCE II Spectral Response Acceleratlon Parameter at 1-s Period 51 s 0.10 51 = 0.20 51 = 0.30 51 = 0.40 51 ~ 0.50 0.8 0.8 0.8 0.8 0.8 1.0 1.0 1.0 1.0 1.0 1.7 1.6 1.5 1.4 1.3 2.4 2.0 1.8 I 1.6 1.5 3.5 3.2 2.8 2.4 2.4 See Section 11.4. 7 of ASCE 7 Note: Use straight-line Interpolation for Intermediate values of S1 For Site Clau = D and s, = 0.427 g, F. = 1.573 7/S/17, 4: 13 PM Design Maps Detailed Report hllps://earthquake.usgs.gov/cn l/designmaps/us/report.php?1cmpla1e-mi 1f6 Equation {11.4-1): SMs = FaSs = 1.056 X 1.110 = 1.172 g Equation {11.4-2): S,u = Fv5 1 = 1.573 X 0.427 = 0.671 g Section 11.4.4 -Design Spectral Acceleration Parameters Equation {11.4-3): S0s = ¾ SMs = ¾ x 1.172 = 0.781 g Equation (11.4-4): 5 0 1 = ¾ SMI = ¾ X 0 .671 = 0.447 g Section 11.4.S -Design Response Spectrum From figure 22-12 CJJ TL = 8 seconds Figure 11.4-1: Design Response Spectrum .. -C LI.? ' T <T0 : s. = S01 ( 04 + 0.8 T /T0 ) T, s Ts T1 : S1 = S115 TI <Ts Tl : s, = so, , T T >Tl : s, = so,Tl /T2 .. ,. ................... , ..... _______ _ ' , ,~ I •• .... :4f1s.•J 7/5/17, 4:13 PM Design Maps Detailed Report https://earthquake.usgs.gov/cn 1/designmaps/us/rcport.php?template=mi ,f 6 Section 11.4.6 -Risk-Targeted Maximum Considered Earthquake (MCER) Response Spectrum The MCE" Response Spectrum Is determined by multiplying the design response spectrum above by 1.5. _.. I I •: ' •r•••·•••••---,-••·•••-•• .... '·~ ',! t •• : p., '-'l. r ,,.-.:) 7/5/17. 4:13 PM Design Maps Detailed Report https:/ /earthquake. usgs.gov/cn I /dcsignmaps/us/report. php'?tem plate=m f6 Section 11.8.3 -Additional Geotechnical Investigation Report Requirements for Seismic Design Categories D through F From Figure 22-z 141 PGA = 0.433 Equation (11.8-1): PGAM = FPGAPGA = 1.067 x 0.433 = 0.462 g Tobie 11.8-1: Site Coefficient F,GA Site Mapped MCE Geometric Mean Peak Ground Acceleration, PGA Class PGA :S PGA = PGA = PGA = PGA ~ 0.10 0.20 0.30 0.40 0.50 A 0.8 0.8 0.8 0.8 0.8 B 1.0 1.0 1.0 1.0 1.0 C 1.2 1.2 1.1 1.0 1.0 D 1.6 1.4 1.2 1.1 1.0 E 2.5 1.7 1.2 0.9 0.9 F See Section 11.4.7 of ASCE 7 Note: Use straight-line Interpolation for Intermediate values of PGA For Site Clan = D and PGA = 0.433 g, F•GA = 1,067 Section 21.2.1.1 -Method 1 (from Chapter 21 -Site-Specific Ground Motion Procedures for Seismic Design) From Figure 22-12 csi CRS = 0.958 From Figure 22-1s 161 C RI = 1.010 7/S/17, 4:13 PM Design Maps Detailed Rcpon hnps://canhquakc:.usgs.gov/cn l/desigJ1maps/us/report.php?tcmplate=mi ,f6 Section 11.6 -Seismic Design Category Table 11.6-1 Seismic Design category Based on Short Period Response Acceleration Parameter RISK CATEGORY VALUE OF Sos I or II III IV 5 05 < 0.167g A A A 0.167g s 505 < 0.33g B B C 0.33g $ S05 < 0,SOg C C D o.sog s Sos D D D For Risk Category= I and SDs = 0.781 g, Seismic Design Category= D Table 11.6-2 Seismic Design Category Based on 1-5 Period Response Acceleration Parameter RISK CATEGORY VALUE OF 501 I orll Ill IV 501 < 0.067g A A A 0.067g $ 501 < 0.133g B B C 0.133g s 501 < 0.20g C C D 0.20g S S01 D D D For Risk Category = I and 501 = 0.447 g, Seismic Design Category = D Note: When 51 Is greater than or equal to 0.75g, the Seismic Design Category Is E for bulldlngs in Risk Categories I, II, and III, and F for those in Risk Category IV, Irrespective of the above. Seismic Design Category = "the more severe design category in accordance with Table 11.6-1 or 11.6-2" = D Note: See Section 11.6 for altematlve approaches to calculating Seismic Design Category. References 1. Figure 22-l: https://earthquake.usgs.gov/hazards/deslgnmaps/downloads/pdfs/2010_ASCE-7 _Flgure_22-l.pdf 2. Figure 22-2: https://earthquake.usgs.gov/hazards/deslg nmaps/downloads/pdfs/20 l0_ASCE-7 _Figure_22·2.pdf 3. Figure 22-12: https://earthquake.usgs.gov/hazards/deslgnmaps/downloads/pdfs/2010_ASCE- 7 _Flgure_22-12.pdf 4 . Figure 22-7: https://earthquake.usgs.gov/hazards/designmaps/downloads/pdts/2010_ASCE-7 _Figure_22-7 .pdf S. Figure 22-l 7: https ://earthquake. usgs.gov/hazards/deslgnmaps/downloads/pdfs/201 0_ASCE- 7 _Flgure_22-l 7.pdf 6. Figure 22-18: https://earthquake.usgs.gov/hazards/designmaps/downloads/pdfs/2010_ASCE- 7 _Flgure_22-18.pdf 7/5/17, 4:13 PM 4i Q.t !:=. 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