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Home My WebLink AboutCT 16-04; HIGHLAND VIEW HOMES; PAVEMENT STRUCTURAL RECOMMENDATIONS; 2017-08-11c7nLrLf I HETHERINGTON ENGINEERING, INC. SOIL &LEQ August 11, 2017 UliQAIlQLElQ NEERING • ENGINEERING GEOLOGY • HYDROGEOLOGY I ri7C0RDC0 Initial Date RECEIVED Project No. 8047.1 co 1 1zoll Log No. 19153 Carlsbad Coastal Views, LLC I .3758 Highland Drive LAND DEVELOPMENT Carlsbad, California 92008 ENGINEERING . I Attention: Mr. Brian Sullivan Subject: PORTLAND CEMENT CONCRETE PAVEMENT AND PERMEABLE I .INTERLOCKING CONCRETE. PA VEMENT STRUCTURAL RECOMMENDATIONS 3758-3794 Highland Drive I Carlsbad, California . . References: 1. "Gebtechnical Investigation, Proposed Eight-Lot Residential Subdivision, I 3758 - 3794 Highland Drive, Carlsbad, California," by Hetherington - Engineering, Inc., dated September 30, 2016. . . I 2. "Infiltration Testing, Proposed Bioretention Basin, 3758 - 3794 Highland Cz Drive, Carlsbad, California," by Hetherington Engineering, Inc., dated - September 30, 2016. Cz I 3. "Preliminary Grading Plan, Highland View Homes, Carlsbad, California," by Coastal Land Solutions, Inc., dated November 29, 2016. I 4. "Permeable Interlocking Concrete Pavements", Fourth Edition 2011, by David R. Smith. I Dear Mr. Sullivan: In response to the request of Ms. Tara Goldberg, Pasco Laret Suiter & Associates, we are I providing structural recommendations for Portland cement concrete pavement and permeable interlocking concrete pavements at the subject site. I The following recommended pavement sections are based on the previously reported R-value of 77 for the on-site soils and an assumed traffic index of 5. I Portland Cement Concrete Pavement We recommend that the Portland cement concrete pavement be a minimum of 6-inches thick. I .Pavement subgrade soils should be scarified to a depth of 12-inches and compacted to at least 95-percent relative compaction as determined by ASTM: D 1557. I I 5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931-0545 www.hetheringtonengineering.com PORTLAND CEMENT CONCRETE PAVEMENT AND PERIvEABLE. INTERLOCKING CONCRETE PAVEMENT. STRUCTURAL RECOMMENDATIONS I .. ProjectNo! LogNo. 19153 August ll,2017 I Page Permeable Interlocking Concrete Pavement . . . . . . I We recommend that the permeable interlocking concrete pavement consist of 3 1/8-inch thick (minimum) concrete, paYers. .(with. edge restraints and sand filled. joints) underlain by a I .bedding sand layer (for leveling).,and compacted base and sübbase. . Materials for use as bedding saud, base and subbase should meet the following specifications': I I I The base and subbase should be compacted to 'a minimum of 90prceIit of the makithürn dry density as determined .by ASTM:. D .1557. Prior to placement of subbase and bas, the underlying subgiade soils should be scarified to a depth of 12-inches and compacted to at I least 90-percent relative compaction (ASTM: D 1557). . . . The opportunity to be of service is sincerely appreciated. If you have any questions, please I call this office. Sincerely HETHERING- G, INC. et in 6 gseth Civil Engineer 3048k' Professional Geologist 3772 I . Geotechnical Engin No. 397 (expires 3/31/18) rmn Certified Engineering Ge Exp. Date_..__ Certified Hydrogeôlog N. BOç . 3/31/18) OrEc I (expires EA. 1153_ I Distribution: 1-via e-mail (bsully59@hotmail.com) OF cP-0 1-via e-mail (tgoldberg@plsaengineei.ing.com) 5-Addressee I I I .. ' • . . HETHERINGTON ENGINEERING, INC. .Materiaf Layer Thickness Speeifièatioii Bedding sand 2 inches ASTM No.,8 stone Base ' . 4 inches . ASTM No 57 stolie Subbase 6 inches . ASTM No.. 2 stone I I HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING • ENGINEERING GEOLOGY • HYDROGEOLOGY I . . . January 26, 2017 .. . . . Project No.. 8 047. 1 I Log No. 18761 Carlsbad Coastal Views, LLC 3758 Highland Drive . I Carlsbad, California 92008 I Attention: Mr. Brian Sullivan Subject: RESPONSE TO CITY OF CARLSBAD GEOTECHNICAL 1 . COMMENTS 3758 - 3794 Highland Drive Carlsbad, California 1 . "Geotechnical References: 1. Investigation, Proposed Eight-Lot Residential Subdivision, 3758 - 3794 Highland Drive, Carlsbad, California," by I Hetherington Engineering, Inc., dated September 30, 2016. "Infiltration Testing, Proposed Bioretention Basin, 3758 - 3794 I .Highland Drive, Carlsbad, California," by Hetherington Engineering, Inc., dated September 30, 2016. I "Preliminary Grading Plan, Highland View Homes, Carlsbad, California," by Coastal Land Solutions, Inc., dated November 29, 2016. . I 4. "Memorandum, Re: CT16-04/PUD16-03/CDP16-21D16-01," by City of Carlsbad Community and Economic Development, Land Development Engineering Staff, dated December 28, 2016. Mr. Sullivan: I Dear In response to the request of Sean Englert, we are providing this response to geotechnical I . comments from the City of Carlsbad (Reference 4). Geotechnical comments were identified in Reference 4. as "Incomplete Items" 18 through 20. Our numbering corresponds toi the city of Carlsbad numbering. . . I 18. Based on the previoualy reported R-Value of 77 and an assumed traffic index of we recommend that the PCC pavement section be a minimum of 6-inches thick. I Pavement subgrade soils should be compacted to at least 95-percent relative compaction. Pervious pavement design should b performed when the type of pervious pavement has been determined. I . . 5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 I 333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931-0545 www.hetheringtonengineering.com Civil Engineer 3 Geotechnical En (expires 3/31/18 RESPONSE TO CITY OF CARLSBAD GEOTECFINICAL COMMENTS Project No 8047.1 I . Log No. 18761 January 26, 2017 Page Due to the sandy nature of the on-site soils, the proposed infiltration should nOt I . adversely impact structural and site stability. 19 Should a cut/fill transition exist within a building pad, over-excavation should be I performed as necessary to maintain a minimum of 3-feet of compacted fill below pad grade The removals should extend to at least 5-feet beyond the limits of the proposed improvements where possible. I The Preliminary Grading Plan (Reference 3) indicates that slopes to a maximum height of 10±-feet at a maximum slope ratio of 2:1 (horizontal to vertical) are ' proposed. Foundations located in close proximity to descending slopes should, maintain a minimum setback of H/3 (H = slope height) fiom the face of descending slopes. 20 Shoring is not anticipated at this time Temporary slopes necessary for grading and/oi to facilitate the construction of the retaining walls may be cut vertically up I to 5-feet in competent terrace deposits or compacted fill where the cuts are not influenced by existing pioperty line constraints or improvements. Temporary slopes higher than 5-feet, located adjacent to existing improvements, and/or cuts I exposing potentially friable/loose/soft soil should be inclined at a slope ratio no steeper than 1:1 (horizontal to vertical). Footings located adjacent to property lines may require deepening to competent terrace deposits should adequate I removals not be possible. Field observations by the Engineering Geologist during grading of temporary slopes is recommended and considered necessary to confirm anticipated conditions and provide revised recommendations if warranted. The opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. Sincerely - rAfBogset GTON ER1NG, INC. OG aul 4 Professional Geologist 3772 Certified Engineering Geologist 11 E.G. Certified Hydrogeologist 591 V. (expires 3/31/18) . • / I Distribution: 1 1-via e-mail (bsu1ly59@hotmail.com) 1-via e-mail (sean@coastal-land-solutjons.cc 5-Addressee I HETHERINGTON ENGINEERING, INC. 'I Hi I , I I INFILTRATION TESTING I Proposed Bioretention Basin 3758 —3794 Highland Drive I Carlsbad, California i. I I I I I 1 I I I I I HETHERINGTON ENGINEERING, INC. I I HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING • ENGINEERING GEOLOGY • HYDROGEOLOGY I September 30, 2016 I ProjectNo. 8047.1 Log No. 18544 Carlsbad Coastal Views, LLC I 375.8 Highland Drive Carlsbad, California 92008 Attention: Mr. Brian Sullivan Subject: INFILTRATION TESTING I Proposed Bioretention Basin 3758 - 3794 Highland Drive I Carlsbad, California References: 1. "Preliminary Grading Plan, 3758 - 3794 Highland Drive, Carlsbad, I California," by Coastal Land Solutions, Inc., dated April 28, 2016. 2. "Geotechnical Investigation, Proposed Eight-Lot Residential Subdivision, 3758 - 3794 Highland Drive, Carlsbad, California," by I Hetherington Engineering, Inc., dated September 0, 2016. Dear Mr. Sullivan: In response to your request, we have performed infiltration testing of existing terrace deposits in the area of the proposed bioretention basin at the subject site. No groundwater was encountered to the maximum depth explored of 15.5-feet in borings excavated at the site (see Reference 2). Infiltration testing was performed by this office on September 23 and 26, 2016 in accordance with the Open Pit Falling Head test method. The approximate locations of the infiltration tests are shown on the attached Plot Plan, Figure 1 and the test results are shown on the attached Infiltration Data Sheets, Figures 2 and 3. The infiltration rates based on the infiltration testing are 7.6-inches/hour and 4.4-inches/hour (without considering safety factors). Completed 1-8 and 1-9 Forms are attached to this report. I I 5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 333 Third Street, Suite 2 • Laguna Beach, CA 02651-2306 • (949) 715-5440 • Fax (760) 931-0545 www.hetheringtonengineering.com INFILTRATION TESTING Project No. 8 047. 1 I Log No. 18544 September 30, 2016 Page 2 I The opportunity to be Of service is sincerely appreciated. If you have any. questions, I 'please call this office. Sincerely, I HETHERTNGTON ENGINEERING, INC. UNALZ Civil Eiig' 30488, Professional Geoloj4ist 3772 meet VRIN Geotechnical Engine Certified Engineering Geo (expires 3/31/18) Certified Hydrogeologist (expires 3/31/18) WE Attachments: Plot Plan STA Figure 1 Infiltration Data Sheets Figures 2 and 3 , 1-8 and 1-~9 Forms QFC Distribution: 1 -via e-mail (bsu11y59@hotmail.com) 1-via e-mail (sean@coastal-land-solutions.com) I 5-Addressee I I I I I I I I . .. HETHERINGTON ENGINEERING INC. .-i (/,1,'k I'All 4Q x 'fit G. 7 2 7,711 f L l " H2 OO ' 166O9W \. 1m-16O188W8j/i55248W 627 ' i4OUQE 8627 138.2UE 169,6 I OOBW 44 K CE - I -—ta 1 ) PAD=163 14 / I I NOT AR 6 I = aew I \\ \ 6 "0,3 11 LOT I / PAD~ii I AD OOLs - \\\/ - IPAD=165.005 i[IJ I I- II/ I 111111 I I I L, 1,1 / /Ic 144 3MW 151 OOPN - \L1 t2l 166.90aw 4165.3M6iw 152.01 FS, IF II 271: H4FL1. LOT 2O 4o 6O 8O 20 REMOVE IREE \--T. D=19 0' /t I LIE !4 I / / / 163.841W / I LT 8 167 - 7)i / / i f / / /OT 4 o LEGEND Ah PAD=170.00,t) -2 6Wn APPROXIMATE LOCATION OF INFILTRATION TEST IT 16 019 AG: 147.00TW T 44.0813W A 1i OR. \,~Yi_ ak 146. Is 1 [, dCP F&J 1r! 4 I J'I I fl III F l 1-0 4 147.251M/ 6 I 162 I 3V 30' PAD=1 57.50 147 508W 146.WW\ I I / 6 J670 4 I _IJ i~rWE 190. 247 1ITh/AMD&'!/////I j / I I 1 -L I hf AP im JN0./18IfI/.tIf/rI/ PLOT PLAN 3758-3794 Highland Drive HETHERINGTON ENGINEERING, INC Carlsbad California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 FIGURE NO. INFILTRATION DATA SHEET Project: 3794 Highland Drive Job No.: 8047.1 Test Hole No.: 2 Soil Classification: SM Excavation by: Mansolf Date Excavated: 9/23/2016 Pre-soak by: CF Pre-soak Date: 9/23/2016 Infiltration Testing by: CF Infiltration Date: 9/26/2016 Excavation and Pre-soak Data Trench Width (ft) Trench Length (ft) Trench Depth (ft) Pre-soak Start Time Pre-soak Water Level (inches) 2 4 1.75 1500 12.0 Infiltration Testing Time Time Interval (mm) Initial Water Level (inches) Final Water Level (inches) A in Water Level (inches) Infiltration Rate (mm/inch) % Change from Previous 0820 60 12.12 6.48 5.64 10.64 0920 0923 60 12.12 7.56 4.56 13.16 23.7 1023 1026 60 12.12 7.68 4.44 13.51 2.7 1126 Figure 3 Project No. 8047.1 Log No. 18544 INFILTRATION DATA SHEET Project: 3794 Highland Drive Job No.: 8047.1 Test Hole No.: 1 Soil Classification: SM Excavation by: Mansoif Date Excavated: 9/23/2016 Pre-soak by: CF Pre-soak Date: 9/23/2016 Infiltration Testing by: CF Infiltration Date: 9/26/2016 I Excavation and Pre-soak Data - Pre-soak Water - Level (inches) 12.0 tration bate ilinch) % Change from Previous .86 .62 11.1 .87 3.3 Figure 2 Project No. 8047.1 Log No. 18544 7 I 1 Project 8047.1 Log No. 18544 Categor-ization of nirriu rn,zs!Tmri '" 1-8 Part 1- Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? fi1I1 lItriy c D thi' QMtEflIRR a thm if flrft. aagm(& &am & PwNkEw SSI UI9 thx1J wfflii Criteria Screening Question Yes No Is the estimated reliable infiltration rate below proposed facility 1 locations greater than 0.5 inches per hour? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Two infiltration tests using Open Pit Falling Head test method were performed in the terrace deposits in the area of the proposed bioretention basin. The test results were 7.6 in/hr and 4.4 in/hr (without considering safety factors). See "Infiltration Testing...,' by Hetherington Engineering, In., dated September 30, 2016. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, 2 groundwater mounding, utilities, or other factors) that cannot be x mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Infiltration in the area of the proposed bioretention basin is considered acceptable from a geotechnical standpoint provided that the geotechnical recommendations included in the 'Geotechnical Investigation..." (Reference 2) are implemented during design and construction. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Project 8047.1 Log No. 18544 Form 1-8 Page 2 of 4 Criteria Screening Question Yes No Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot x be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Storm water pollutant concerns in the area of the proposed bioretention basin are unknow at this time. Borings at the site with a maximum depth of 15.5-feet did not encounter groundwater. Infiltrated water will migrate at least 15.5-feet before reaching groundwater. In addition we are not aware of any known soil contamination present at the site. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of x contaminated groundwater to surface waters? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: No ephemeral streams are present at the site. Groundwater was not encountered to a depth of at least 15.5-feet and we are not aware of any contaminated groundwater in the site vicinity. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. If all answers to rows 1 - 4 are "Yes" a full infiltration design is potentially feasible. The Part art feasibility screening category is Full Infiltration Result * If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 LL "To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings Project 8047.1 Log No. 18544 Form 1-8 Page 3 of 4 Part 2— Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria Screening Question Yes No Do soil and geologic conditions allow for infiltration in any 5 appreciable rate or volume? The response to this Screening x Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Due to providing a Full Infiltration' result to Part 1, this criteria need not be answered. See response to Criteria 1. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, 6 groundwater mounding, utilities, or other factors) that cannot x be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Due to providing a "Full Infiltration" result to Part 1, this criteria need not be answered. See response to Criteria 2. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. I I I I I Project 8047.1 Log No. 18544 Form - - 1-8i Page 4 of 4 Criteria Screening Question Yes No Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns 7 (shallow water table, storm water pollutants or other factors)? X The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Due to providing a 'Full Infiltration" results to Part 1, this criteria need not be answered. See response to Criteria 3. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. Can infiltration be allowed without violating downstream water 8 rights? The response to this Screening Question must be based on a X comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: This question requires the expertise of water-rights lawyers to determine if any violation can be expected downstream by reducing the runoff via infiltration of the water into the bioretention basin. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. If all answers from row 1-4 are yes then partial infiltration design is potentially feasible. Part 2 The feasibility screening category is Partial Infiltration. Result* If any answer from row 5-8 is no, then nfiltration of any volume is considered to be infiltration infeasible within the drainage area. The feasibility screening category is No Infiltration. U- 10 be completed using gathered site information and best professional Judgment considering the definition of Mt!P In the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings I I I LI I Project 8047.1 Log No. 18544 LM F Factor of izitsS AS.. - - - Factor Category I Factor Description I Assigned Weight (w) I Factor Value (v) Product (p) p = w x v A Suitability Assessment Soil assessment methods 0.25 1 0.25 Predominant soil texture 0.25 1 0.25 Site soil variability 0.25 1 0.25 Depth to groundwater / impervious layer 0.25 1 0.25 Suitability Assessment Safety Factor, SA = p 1.00 B Design Level of pretreatment! expected sediment loads 0.5 2 1.00 Redundancy/ resiliency 0.25 2 0.50 Compaction during construction 0.25 2 0.50 Design Safety Factor, Sa = Ep 2.00 Combined Safety Factor, S10 ,1= SA SB 2.00 Observed Infiltration Rate, inch/hr, Kobse...ed (corrected for test-specific bias) 7.6 & 4.4 Design Infiltration Rate, in/hr, = Kobscrvei / Stotal 3.8 & 2.2 use 3.0 (aye) Supporting Data Briefly describe infiltration test and provide reference to test forms: Two Open Pit Falling Head tests were performed. See 'Infiltration Testing..." by Hetherington Engineering, Inc., dated September 30, 2016. I I I I I ,F1 I I I I I I I .GEOTECHNICAL INVESTIGATION Proposed Eight-Unit Residential Development 3758 - 3794 Highland Drive i Carlsbad, California I I I I I I I I . I I I I . HETHERINGTON ENGINEERING, INC.. I I HETHERINGTON ENGINEERING, INC. SOIL & FOUNDATION ENGINEERING • ENGINEERING GEOLOGY • HYDROGEOLOGY I September 30, 2016 Project No. 8047.1 I Log No. 18545 Carlsbad Coastal Views, LLC I 3758 Highland Drive Carlsbad, California 9200.8 I Attention: Mr. Brian Sullivan Subject: GEOTECHNICAL INVESTIGATION I Proposed Eight-Unit Residential Development 3758 - 3794 Highland Drive Carlsbad, California I References: Attached I Dear Mr. Sullivan: In accordance with your request, we have performed a geotechnical investigation for the I proposed construction of an eight-unit residential development at the subject site. Our work was performed during September 2016. The purpose of our investigation was to evaluate the soil and geologic conditions at the site in order to provide grading and I foundation recommendations for the proposed development. scope of work included the following: I Our Research and review of available plans and geologic maps/literature pertinent to the I .site (see References). . Subsurface exploration consisting of four borings for soil sampling and geologic I observation. Laboratory testing of samples obtained from the subsurface exploration. I • Engineering and geologic analysis. Preparation of this report presenting the results of our field and laboratory work, I . - analyses, and our conclusions and recommendations. I I 5365 Avenida Encinas, Suite A • Carlsbad, CA 92008-4369 • (760) 931-1917 • Fax (760) 931-0545 I 333 Third Street, Suite 2 • Laguna Beach, CA 92651-2306 • (949) 715-5440 • Fax (760) 931-0545 www.hetheringtonengineering.com I GEOTECHNICAL INVESTIGATION Project No. 8047.1 I Log No. 18545 September 30, 2016 Page 2 I SITE DESCRIPTION I The subject propertyis located at 3758 - 3794 Highland Drive, Carlsbad, California (see Location Map, Figure 1). The property is approximately 2-acres in size and slopes gently to the east. The site currently supports a single-family residence and several detached I outbuildings. The site is bounded by devebped residential properties to the north and south, by Highland Drive to the west and by a school to the east. I PROPOSED DEVELOPMENT Proposed development consists of an eighr-unit residential subdivision. Existing site I improvements will be demolished. We anticipate one and/or two story, wood-frame structures founded on conventional continuous/spread footings with slab-on-grade ground I floors. Building loads are expected to be typical for this type of relatively light construction. Proposed grading consists of cuts and fills on the order of approximately 5 to 10-feet and less with import required to achieve design finished grades. Retaining I walls and slopes, inclined at 2:1 (horizontal t3 vertical), up to approximately 5 to 10-feet high are proposed to facilitate grade changes. We anticipate that the proposed private drive aisle will consist of asphalt concrete pavement. I SUBSURFACE EXPLORATION Subsurface conditions were explored by excavating four hollow-stem auger borings to I depths of 10.5 to 15.5-feet below existing sit grades. The approximate locations of the exploratory borings are shown on the attached Plot Plan, Figure 2 and Geologic Cross- Section, Figure 3. The subsurface exploration was supervised b' an engineer from this office, who visually classified the soil, and obtained relatively undisturbed and bulk soil samples for I laboratory testing. The soils were visually classified according to the Unified Soil Classification System. Classifications are shown on the attached Boring Logs, Figures 4 I through 7. LABORATORY TESTING I Laboratory testing was performed on samples obtained during the subsurface exploration. ' Tests performed consisted of the following: Dry Density/Moisture Content (ASTM D 2216) I HETHERINGTON ENGINEERING, INC. Ymn PtT T WF31'FIE V4 32 MAG111M Hosp _\ GROVE i-ct\. 31'PARK 41,; 7k I, (AU1ffiY !i1 IOREST \•A ?' Y.. . I - tAGU.QR , kWA On n--. isit i , M- OAM \ \i URLS 8 CH V ADAPTED FROM: The Thomas Guide, San Diego County, 57th Edition, Page 1106 SCALE: 1-2000' (1 Grid Equals: 0.5 x 0.5 miles) LOCATION MAP 3758 - 3794 Highland Drive HETHERINGTON ENGINEERING, INC. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 1 FIGURE NO. I GEOTECHNICAL INVESTIGATION Project No. 8047.1 I Log No. 18545 September 30, 2016 Page I Direct Shear (ASTM: D 3080) I • Soluble' Sulfate (Cal Test 417) R-Valüe (Cal Test 301) I . Results of the dry density and moisture content determinations are presented on the I attached Boring Logs, Figures 4 through 7. The remaining laboratory test results are presented on the attached Laboratory Test Results, Figure 8. Previous laboratory, test results by Strata-Tech, Inc. are included in Appendix A to this report. I SOIL AND GEOLOGIC CONDITIONS I 1. Geologic Setting The subject site lies within a relatively level marine terrace that is contained within the coastal plain region of northern San Diego County, California. The coastal plain I region is characterized by numerous regressive marine terraces of Pleistocene age that have been established above wave-cut platforms of underlying Eocene bedrock and were formed during glacio-eustatic changes in sea level. The terraces extend from I areas of higher elevations east of the site and descend generally west-southwest in a "stairstep" fashion down to the present day coastline. These marine terraces increase in age eastward. The site area is contained within the central portion of the USGS I San Luis Rey 7.5-minute quadrangle. As observed in the borings, the site is underlain by Quaternary terrace deposits. I Localized areas of fill are anticipated associated with construction of the existing single-family residence. Structurally, bedding within the terrace deposits is I considered to be essentially massive. The terrace deposits are granular and have. a very low expansion potential. 2. Geologic Unit Terrace Deposits - Encountered in all of the borings, the terrace deposits are I considered massive and consist of red brown silty sand that is damp to moist and dense. I I HETHERINGTON ENGINEERING, INC. I I GEOTECHNICAL INVESTIGATION Project No. 8047.1 I Log No. 18545 September 30, 2016 I .Page4 3. Groundwater I Groundwater or seepage was not encountered in the exploratory borings. It should be noted, however, that fluctuations in the amount and level of groundwater may occur due to variations in rainfall, i1T1gatio and other factors that may not have been I evident at the time of our field investigation. I SEISMICITY Based on review, of the available geologic maps/literature, there are no active or potentially active faults that traverse the subject site, and the property is not located I within the currently mapped limits of an Alquist-Priolo Earthquake Fault Zone. The following table lists the known active faults that would have the most significant impact i on the site: - -- - I I SEISMIC EFFECTS Ground Accelerations - The most significant probable earthquake to affect the property would be a 7.0 I magnitude earthquake on the Rose Canyon fault. Based on Section 1803.5.12 of the 2013 California Building Code and Section 11.8.3 of ASCE 7, peak ground I accelerations (PGAM) of 0.469g are possible for the design earthquake. Landsliding I Review of the referenced geologic maps/literature indicates that the subject property is not included within the limits of any previously mapped landsliding. The risk of seismically induced landsliding affec:ing the site is considered low due to the gently I sloping site topography. I. HETHERINGTOFJ ENGINEERING, INC. Maximum Probable Fault Earthquake Slip Rate (Moment Magnitude) (mm/year) Rose Canyon 7 0 5.0 (8.9-kilometers/ 5.5-miles southwest) Elsinore (Julian Segment) 6.8 1 5 (37- kilometers/ _23-miles_northeast) I . GEOTECHNICAL INVESTIGATION . Project No. 8047.1 I Log No. 18545 . . . . . September 30, 2016 Page I . Ground Cracks . . . I The .risk of fault surface rupture due to active faulting is considered low die. to :the absence of -known active faults on site. Ground cracks due to 'shaking from. seismic events in the region are possible, as with all of southern California. I. Liquefaction. . The risk of seismically induced liquefaction within the site is consideied low due to I the dense nature of the terrace deposits and absence of shallow groundwater..: Tsunamis . . . .5. I . The site is not located within a mapped tsunami inundation area (Reference 2). The I elevation risk of a tsunamis event adversely impacting the site is considered low due to the of the property above sea level. I .. CONCLUSIONS AND RECOMMENDATIONS . . . General ..: . I The proposed development is considered feasible from a geotecimical standpoint. Grading and foundation plans should take into account the appropriate geotechnical I .features of the site. Provided that the recommendations presented in this report and good construction practices are utilized during design and construction, the proposed construction is not anticipated to adversely impact the adjacent properties from a I geotechnical standpoint. Seismic Parameters for Structural Design . I ' Seismic considerations that may be used for structural design at the site include the following: I a. Ground Motion - The proposed structures should be designed and constructed to resist the effects of seismic ground motions as provided in Section 1613 of the I 2013 California Building Code. . . . . Site Address: 3758 - 3.794 Highland Drive, Carlsbad, California I Latitude: 33.15640.. . . Longitude: -117.3314° . . . . . . . . I. . . . HETHERINGTON ENGINEERING, INC. . . p... I GEOTECHNICAL INVESTIGATION Project No. 8047.1 I Log No. 18545 September 30, 2016 Page '6 I Spectral Response Accelerations - Using the location of the property and data obtained from the LJ.SQ.S. Earthquake Hazard Program, short period Spectral I Response Accelerations S (0.2 second period) and S1 (1.0 second period) are: Sl.130g I Site Class - In accordance with Chapter 20 of ASCE 7, and the underlying I geologic conditions, a Site Class D is considered appropriate for the subject property. I d. Site Coefficients F and F - In accordance with Table 1613.33 and considering the values of S and S, Site Coefficients for a Class D site are: I F= 1.566 I e. Spectral Response Acceleration Parameters Sm and Smi - In accordance with Section 1613.3.3 and considering the values of S and S, and Fa and F, Spectral I Response Acceleration Parameters for the Maximum Considered Earthquake are: Sin, (Fa)(Ss) = 1.184g i Sm1 = (F)(Si) = 0.679g f Design Spectral Response Acceleration Parameters Sd and S - In accordance with Section 16 13.3.4 and considering the values of Sm and Sm1, Design Spectral I Response Acceleration Parameters for the Maximum Considered Earthquake are: Sd0.789g I Sd1 = 0.453g Long Period Transition Period - A Long Period Transition Period of TL = 8 I seconds is provided for use in San Diego County. Seismic Design Category - In accordance with Tables 1604.5, 1613.3.5(1) and I 1613.3.5(2), and ASCE 7, a Risk Category II and a Seismic Design Category D are considered appropriate for the subject property. I I HETHERINGTON ENGINEERING, INC. I I GEOTECHNICAL INVESTIGATION Project No. 8047.1 I Log No. 18545 September 30, 2016 Page 7 1 3. Site Grading ' Prior to grading, the site should be cleared of existing surface obstructions, vegetation and debris. Materials generated during clearing should be disposed of at an approved location off-site. Holes resulting from the removal of any buried obstruction should I be filled with compacted fill or lean concrete. Seepage pits and./or septic systems, if encountered during site development, should be abandoned in accordance with local guidelines. Within the limits of proposed improvements and to 3-feet beyond, I existing loose fill or disturbed terrace deposits should be removed down to approved undisturbed terrace* deposits (estimated at 27feet). Due to disturbance as a result of demolition, we anticipate removal depths on the order of 3-feet below existing site grades in the area of the existing residence. Actual removal depths should be determined in the field by the Geotechnical Consultant .based on conditions exposed I during grading. The exposed subgrade soils should be scarified 6 to 8-inches, moisture conditioned to I about optimum moisture content and compacted by mechanical means to a minimum relative compaction of 90-percent (ASTM: D 1557). Fill should be moisture conditioned as necessary to about optimum moisture content and compacted by I mechanical means in uniform horizontal lifts of 6 to 8-inches in thickness. All fill should be compacted to a minimum relative compaction of 90-percent based upon ASTM: D 1557. The on-site materials are suitable for use as compacted fill provided all vegetation and debris are removed. Rock fragments over 6-inches in dimension I and other perishable or unsuitable materials should be excluded from the fill. Proposed cut and fill slopes should be inclined at a slope ratio of 2:1 (horizontal to I vertical) or flatter. All grading and compaction should be observed and tested as necessary by the I Geotechnical Consultant. 4. Foundation and Slab Recommendations The proposed structures may be supported on conventional continuous/spread footings founded at least 18-inches in compacted fill and/or terrace deposits. I Continuous footings should be at least 12-inches wide and reinforced with a minimum of four #4 bars, two top and two bottom. Foundations located adjacent to I utility trenches should extend below a 1:1 (horizontal to vertical) plane projected I upward from the bottom of the trench. HETHERINGTON ENGINEERING, INC. I GEOTECHNICAL INVESTIGATION. ProjectNo. 8047.1 I Log No. 18545 'September 30, 2016 ' Page .8 Foundations bearing as recommended maybe designed for ,a dead plus live load bearing value of 2000-pounds-per-square-foot. This value may be increased by one- ' third for loads including wind and seismic forces. A lateral bearing value of 250- pounds-per-square-foot per foot of depth to a maximum value of 2000-pounds-per- square-foot and a coefficient of 'friction between foundation soil and concrete of 0.35 I may be assumed. These values assume that footings will be poured neat against the foundation soils. Footing excavations should be observed by the Geotechnical Consultant prior to the placement of reinforcing steel in order to verify that they are I founded in suitable bearing materials. Total and differential settlement due to foundation loads is considered to be less than 1 3/4 and 3/8-inch, respectively, for foundations founded as recommended. I reinforced Slab-on-grade floors should have a minimum thickness of 5-inches, and should be with #4 bars spaced at 18-inches, center to center, in two directions, and supported on chairs so that the reinforcement is at mid-height in the slab. Floor slabs, I including garages, should be underlain with a moisture vapor retarder consisting of a minimum .1 0-mu polyethylene membrane. At least 2-inches of sand should be placed over the vapor retarder to assist in concrete curing and at least 2-inches of sand should be placed below the vapor retarder. The vapor retarder should be placed in I accordance with ASTM: B 1643. Prior to placing concrete, the slab subgrade soils should be thoroughly moistened. I Vapor retarders are not intended to provide a waterproofing function. Shoild moisture vapor sensitive floor coverings be planned, a qualified consultant/contractor should be consulted to evaluate moisture vapor transmission rates and to provide I recommendations to mitigate potential adverse impacts of moisture vapor transmissions on the proposed flooring. I 5. Retaining Walls I Retaining walls free to rotate (cantilevered walls) should be designed for an active pressure of 35-pounds-per-cubic-foot (equivalent fluid pressure). Walls restrained from movement at the top should be designed for an at-rest pressure of 60-pounds- per-Pubic-foot (equivalent fluid pressure). These values are based on level backfill consisting of onsite granular soils. Any additional surcharge pressures behind retaining walls should be added to these values. Retaining wall foundations should be I ' designed in accordance with the foundation recommendations provided previously in I this report. HETHERINGTON ENGINEERING, INC. I I GEOT.ECHNICAL rNVESTIGATION. Project No. 8047.1 I Log No. 18545 September 30, 2016. Page I Retaining walls should be provided with adequate, drainage to prevent buildup of hydiostatic pressuie and should be adequately waterproofed The subdram system I behind retaining walls should consist at a minimum of 4-inch diameter Schedule 40 (or equivalent) perforated (perforations "down") PVC pipe embedded in at least 1- cubic-foot of 3/4 inch crushed tuck per lineal foot of pipe all wrapped in an approved I .. filter fabric. The subdrain system should be connected to a solid outlet pipe with a minimum of 1-percent J.all, that discharges to a suitable drainage device Recommendations for wall waterproofing should be provided by the Project Architect I and/or Structural Engineer. . The lateral pressure, on retaining walls due to earthquake motions (dynamic lateral I . . force) should be calculated as PA = 3/8 ,y .H2kh where . . . ... PA = dynamic lateral force (lbs/fl) : I . = unit weight = 1'20pcf . . H = height of wall (feet) . . . . . . I k11 seismic coefficient =0.156 The dynamic lateral force may also be expressed as I 4-pcf (equivalent fluid I . pressure). I The dynamic lateral force is in addition to the static force and should be applied as a triangular distribution at 1/3H above the base of the wall. The dynamic lateral force need not be applied to retaining walls 6-feet or less in height. I , 6. Hardscape I .Concrete flatwork should be at least 5-inches thick (actual) and reinforced with No. 4 bars spaced at 18-inches on-center (two directions) and placed on chairs so that the reinforcement is in the center of the concrete. Contraction joints should be provided I at 8-feet spacing (maximum). Joints should create square panels where possible. .For rectangular panels (where necessary) the long dimension should be no. more than: 1.5 times the short dimension. Joint depth should be at least 0.25 times. the flatwork' thickness. Expansion joints should be thoroughly sealed to prevent the infiltration of water into the underlying soils. . I .. I .. ... HETHERINGTON ENGINEERING, INC. I GEOTECHNICAL INVESTIGATION Project No. 8047.1 • Log No. 18545 • September 30, 2016 Page 10 I Concrete 7. Asphalt Pavement I Based on an R-value of 77 and an assumed traffic index of 5, we recommend that the pavement section for the proposed private drive aisle consist of 3-inches of asphalt concrete pavement over 4-inches of Class 2 aggregate base (Caltrans). Pavement I subgrade and aggregate base should be compacted to at least 95-percent relative compaction and tested by the Geotechiiical Consultant. Sulfate Content A representative sample of the on-site soils was submitted for sulfate testing. The I result of the sulfate test is summarized on the Laboratory Test Results, Figure 7. The sulfate content is consistent with a not applicable sulfate exposure classification .per Table 4.2.1 of the American IConcrete Institute Publication 318, consequently, no I special provisions for sulfate resistant concrete are considered necessary. Other corrosivity testing has not been performed, consequently, on-site soils should be assumed to be severely corrosive to buried metals unless testing is performed to I indicate otherwise. Drainage The following recommendations are intended to minimize the potential adverse I effects of water on the structures and appurtenances. a. Consideration should be given to providing the structures with roof gutters and downspouts that discharge to an area drain system and/or to suitable locations I away from the structure. I b. All site drainage should be directed away from the structures. c. No landscaping should be allowed against the structures. Moisture accumulation or watering adjacent to foundations can result in deterioration of building I materials and may affect the performance of foundations. Irrigated areas should not be over-watered. Irrigation should be limited to that I d. required to maintain the vegetation. Additionally, automatic systems must be seasonally adjusted to minimize over-saturation potential particularly in the I winter (rainy) season. I HETHERINGTON ENGINEERING, INC. I GEOTECI{NICAL INVESTIGATION Project.No. 8047.1 I LogNo 1854.5 September 30, 2016 Page. 11 I All yard and roof drains should be periodically checked to verify they are not blocked and flow properly, and maintained as necessary. I 1 0. Recommended Observation and Testing During Construction I The following tests and/or observations by the Geotechnical Consultant are recommended: I a. Observation and testing during site grading. Observation of foundation excavations prior to placement of forms and I reinforcement. I . Utility trench backfill. Hardscape/driveway subgrade and base. I e. Retaining wall backdrains and backfill. I i 1. Grading and Foundation Plan Review Grading and foundation plans should be reviewed by the Geotechnical Consultant to confirm conformance with the recommendations presented herein or to modify the I recommendations as necessary. I LIMITATIONS The analyses, conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our investigation and further assume the I excavations to be representative of the subsurface conditions throughout the site. If different subsurface conditions from those encountered during our exploration are .observed or appear to be present in excavations during construction, the Geotechnical I Consultant should be promptly notified for review and reconsideration of recommendations. I Our investigation was performed using the degree of care and skill ordinarily exercised, under similar circumstances, by reputable Geotechnical Consultants practicing in this or I similar localities. No other warranty, express or implied, is made as to the conclusions and professional advice included in this report. I. HETHERINGTON ENGINEERING, INC. I I QEOTECFHICAL Project No. 8047.1 I LogNo. 18545 September 30, 2016 Page 12 I This opportunity to be of service is sincerely appreciated. If you have any questions, please call this office. I Sincerely, HETHERINGTON ENGINEERING, INC. Bogseth • Civil Engineer 3 04 Professional Geologist 3772 I Geotechnical Engineer ertified Engineering (expires 3/31/18) t cg 'ertified Hydrogeolog La zze expires 3/31/18) Attachments: Location Map Figure 1 Plot Plan Figure 2 CALIV Geologic Cross-Section Figure 3 I Boring Logs Figures 4 through 7 Laboratory Test Results Figure 8 Straf-Tr.h Tn T)ntn Annndix A S - flu .#J.ILCLAS tJL,I4iI7 .J.d.t44IJAJu1nunL...Insn) 1-via e-mail (sean@coastal-land-solutions.com) HETHERINGTON ENGINEERING, INC. REFERENCES 1.. ASCE 740, "Minimum Design Loads for Buildings and Other Structuies", American Society of Civil Engineers/Structural Engineers Institute, dated May 2010. California Geological Survey, "Tsunami Inundation Map for Emergency Planning - Encinitas Quadrangle", California Geologic Survey, June 1, 2009. Coastal Land Solutions, Inc., Preliminary Grading Plan, 3758 3794 Highland Drive, Carlsbad, California, dated April. 28,. 2016. ICBO, California Building Code, 2013 Edition. I . ICBO, "Maps of Known Active Fault Near-Source Zones in California and Adjacent Portions of Nevada," California Division of Mines and Geology, 1998. I 'Peterson, Mark P., et al, "Documentation for the 2008 Update of the United States Seismic Hazards Maps," USGS Open File Report 2008-1128, dated 2008. I National Strata-Tech, Inc., "Geotechnical Engineering Investigation of Proposed Multi I California," Family Residential Development, 3758 - 3794 Highland Drive, Carlsbad, dated May 14, 2016 (no boring logs included). Tan, Siang S. and Kennedy, Michael P., "Geologic Maps of the Northwestern Part I of San Diego County, California," California Division of Mines and Geology, Open-File Report 96-02, dated 1996. I 9. Tan, Siang S. and Giffen, Desmond G., "Landslide Hazards in the Encinitas Quadrangle, San Diego County, California," California Division of Mines and I Geology, Open-File Report 96-04, dated 1995. 10. USGS, Earthquake Hazard Program, Seismic Design Maps. I 11. 2007 Working Group and California Earthquake Probability, "The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF-2)," USGS Open File Report 2007-1437 and California Geological Survey Special Report 203, dated I 2008. I I I I Project No. 8047.1 Log No. 18545 I . HETHERINGTON ENGINEERING, INC. 1 \ ) 16 FE NOT .,PART eAD / I / 164.72TW TT °i I PAP= .0 / F qmw fUIW 17189 Iva 36TW 16 15 LOT 0 20 40 60 80 70.4 qtA 1 '241 NA 1 B-4 k / J i -1A1 RAW I I LT 8 / / / IJ ,/ 159 OO9W / 1 7 Tfl ,' IOT 4 F1 hi 143 02TC / LEGEND PAO=17OO A=147 ) l371E ff B-4 APPROXIMATE LOCATION OF BORING - ' j / 16996F5 - , 1078W it \I \ / f 41 - / I A' / A A' / ___ - APPROXIMATE : \\\) jic / ) / APPROXIMATE LOCATION OF GEOLOGIC CROSS-SECTION 1 143 68R I / — — - j' C 161 W1BW 8 7( / \ 147 001W -h--u 147001W 6i1Y1 FtNC8 J I 46.008111 I / I It / 5 H I] I .14 SH 7.5016 10, 1, 12P94p 0 1' : :i /1 47,508W 146348W IJJ \APO.11681f/I/'//'/ PLOT PLAN _j_ 11 11 - I 3758 3794 Highland Drive H I rLi. ( — / I l I ,i 1 / / I I ill HETHERINGTON ENGINEERING, INC. Carlsbad, California GEOTECHNICAL CONSULTANTS PROJECT NO. 8047.1 FIGURE NO. 2 El?. 200 180 160 140 B-I (PROJECTED) Si Si 'I 8 I I [ EXISTING GRADE PROPOSED GRADE B-2 (PROJECTED) r I I LOT I -i LOT PRIVATE DRIVE LOT4 - - TERRACE DEPOSITS I 200 140 120 I TREND: N25E SCALE: 1"=20' 0 1 2 0 10 20 30 40 120 Av — — — — — — — — — — — — — — — — — — — DEPTH (FEET) 0 = CD CD C C I I I I I I BULK SAMPLE O m > 8 ---4 FI I*1I DRIVE SAMPLE 0) N) N) 01 (71 - z m ?- BLOWS/FOOT -H cC) --- - - oz 0 DRY DENSITY C) - C 0) 0). cf) cd cz Z C) MOISTURE 9) 9' 0 c Z N) CONTENT (%) rn __________ > m SOIL CLASS. _____________________________________________ (U5.C.S.) cnZ - -1 I 0 CD Z C CL - I w I,, G) B 0 -cn 23 -1 o • -1 - C/)C4 0 z 0_- T1 m 0 Z (D O 00 a- 0 a - --0 m C() C4 CL -.4 • Cfl-4 0 =c_) CL 0 _ m r-. - - CD 0 - I Ifl C (1) B z (1) B CD o 0 - -- DRILLING COMPANY: Scoffs RIG: Track Mounted DATE: 09112116 BORING DIAMETER: 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION; I i-i H a4 0 S U) rX4 Z o° H U)—. i-i BORING NO. B-2 N ) D ZOO H N 04 -1 :C32 I-I 0 r:1 - 44 >1 0 Cl) E-' I-I Z ,:ICJ) 1-1' çii 0 O 0 -.- 00 o 0 - SOIL DESCRIPTION - - TERRACE DEPOSITS: Red brown silty fine to medium sand, - damp, dense - - 50/6" 106 5.5 - 5.0- ' 50/6" 116 4.4 - 10.0- 50/6" 88 7.4 - - A @ 11' Difficulty drilling, chalk like fragment in tailings - Total depth: 15.5 feet - No groundwater - No caving 15.0- 50/6" 98 6.9 - 20.0---- BORING LOG 3758 - 3794 Highland Drive HETHERINGTON ENGINEERING, INC. Carlsbad, California PROJECT NO. 8047.1 FIGURE NO. 5 GEOTECHNICAL CONSULTANTS I I I I I I I I I I I I I I I I I I I DRILLING COMPANY: Scott's RIG: Track Mounted DATE: 09/12/16 BORING DIAMETER: 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION:' El 8 El - dP U)-. BORING NO. B-3 CI) 1 Z i El C') xi Cl) lxi 0— 0 z El 111 00 (14 H 0 44 >-' U Cl) El I-I Z ,-4 U) '- 01x l IZ 00 00 SOIL DESCRIPTION -00 --— — _________________________________ TERRACE DEPOSITS: Red brown silty fine to medium sand, — - - damp, dense - 47/6" 104 3.3 - 5.0— 50/6" 103 4.5 10.0— 50/6' 109 7.5 - - Total depth: 10.5 feet - No groundwater - No caving 15.0- 20.0------- BORING LOG 3758 - 3794 Highland Drive HETHERINGTON ENGINEERING, INC. Carlsbad, California PROJECT NO. 8047.1 FIGURE NO. 6 GEOTECHNICAL CONSULTANTS DRILLING COMPANY: Scott's RIG: Track Mounted DATE: 09/12/16 BORING DIAMETER, 8" DRIVE WEIGHT: 130 lbs. DROP: 30" ELEVATION: ' -t El i1 P. El S El d° Cl)—.. BORING NO. B-4 rU) E-' Z cr El ,) El U) . 11 U) 0 Z El. r) 00 t-H 0 4-1 >-' C.) (1) El HZ E:lC/) H-- _____ 5 SOIL DESCRIPTION — 0.0— - ____ TERRACE DEPOSITS: Red brown fine to medium sand, - damp, dense - 50/6" 114 7.8 - 5.0— 50/6" 113 7.7 10.0— S50/5.5"120 11.1 - Total depth: 10.5 feet - No groundwater - No caving - 15.0— - 20.0---- BORING LOG 3758 - 3794 Highland Drive HETHERINGTON ENGINEERING, INC. Carlsbad, California PROJECT NO. 8047.1 FIGURE NO. 7 GEOTECHNICAL CONSULTANTS E I I I I I I I I I I I I I I I I I I I LABORATORY TEST RESULTS r (ASiM 1O8O) 8 '1' -• - . ..; .. 4 S 71 jjieLcafion r. '-Aig Intcrnai Retharii1 "- Fiictiith(°) Y(psf) B-i 2' 34 0 Undisturbed, soaked consolidated, drained 1- 6 SULFATE TEST RESULTS ' 4 r(EPA038) - I Locatioi So1ublt SJfatem Soil Sample B-1@otoIQ' 0.0210 B-3@0to10' 0.0100 R-Value.-- (Cal Test 301) Sample Location WValue -. Pavement Subgrade 77 Figure 8 Project No. 80471 Log No. 18545 APPENDIX A (Strata-Tech, Inc. Laboratory Test Results) G ED C 0 N S Li LT ANT S APPENDIX A This appendix contains a description of the field investigation, laboratory testing procedures and results, site plan, and exploratory logs. FIELD INVESTIGATION 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 earth materials were obtained at frequent intervals by driving a thin- walled steel sampler by the hydraulic action of the backhoe bucket. The material was retained in brass rings of 2.41 inches inside diameter and 1.00 inch height. The central portion of the sample was in close-fitting, watertight containers for transportation to the laboratory. Descriptions of the soils encountered are presented on the attached boring Logs. The data presented on these 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. Laboratory Testing Field samples were examined in the laboratory and a testing program was then established to develop data for preliminary evaluation of geotechnical conditions. Moisture Density Field moisture content and dry density were determined for each of the undisturbed soil samples. The dry density was determined in pounds per cubic foot. The moisture content was determined as a percentage of the dry soil weight. The results of the tests are shown in the test results section of this appendix. Compaction Character Compaction tests were performed on bulk sample of the existing soil in accordance with ASTM Dl557-07. The results of the tests are shown in the test results section of this appendix. Shear Strength The ultimate shear strengths of the soil, remolded soil, highly weathered bedrock and bedrock was determined by performing direct shear tests. The tests were performed in a strain-controlled machine manufactured by GeoMatic. The rate of deformation was 0.005 inches per minute. Samples were sheared under varying confining pressure, as shown on the "Shear Test Diagrams". fl G 0 N 6 Li L T A N T 6 The samples indicated assaturated were artificially saturated in 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 of the laboratory standard with low confining pressure. TEST RESULTS Maximum Density/Optimum Moisture (ASTM : D- 1557Q7) Boring Depth in Ft Maximum Density Optimum Moisture (pet) (%) 3 1-3 124 12.0 In-Situ Dry Density! Moisture Boring Depth in Feet Dry Density (pet) Moisture (%) 3.5 114.0 6.1 3 4 114.1 6.0 3 9 113.7 5.8 Direct Shear Cohesion Angle of Internal Boring Depth in Feet Friction F' / (degrees) 3 4 lOG 31 APPENDIX B SHEAR TEST RESULT 90 %) 4 H 3 '- (I) 1 7- 0 1 0 1 2 3 4 Confining Pressure (kips/sq. ft) Stress - Displacement Diagram : I H *1 KIP w 2 L-12 KIP IV Horizontal Displacement (X 1/10 inch) Natural soil samples were submerged for at least 24 hours. The sample had a density of 113 lbs./cu.ft. and a moisture content of 17 %. Cohesion = 100 psf Friction Angle = 31 degrees Based on 80% peak strength or ultimate strength, whichever is lower Geotechnical Engineering Investigation Work Order 277515 3758 Highland Dr. ri,i -r c'l;c,rn; Plate No. 5 - '...cI 11JA \jcllllljl 111c4 STRATATECH, INCA