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HomeMy WebLinkAboutPD 16-11; MANATAN RESIDENCE; FINAL SOILS REPORT; 2020-08-10LAKESHORE ENGINEERING EST.1987 9062 Washington Avenue, Westminster, CA. 92683 Phone/Text: (951) 329-6730; Email:lakeshoreengineerin@yahoo.com August 10, 2020 Project No. PD16-11.FC Client: Mr. Alex Manantan (760) 271-9464 E:a_manantan@msn.com Attention: City of Carlsbad, Engineering Department, San Diego County, CA. Subject: Final Compaction Compaction Report (Manantan’s Residence) 2665 Cazadero Drive, Carlsbad, CA. Lot 740, La Costa Meadows Unit 4, map No. 7367 A.P.N. 215-460-02-00; City File No. PD 16-11 Gentlemen; INTRODUCTION This report summarizes our field density tests and observations made for the site during the construction of the during the subject residence. The purpose of this report is to document that the entire grading operation for subject property has been completed in conformance with the recommendations of the project geotechnical reports and that the fill materials have been properly placed and compacted in accordance with the project geotechnical reports and the City of Carlsbad Grading ordinance. Periodic field testing and observations were provided by a representative of Lakeshore Engineering to check the grading contractors on compliance with the approved drawing and job grading specifications. The present of our field representative at the site is to provide the property owner a source of professional advice, opinions and recommendations based upon our field observations of the contractor’s work. The opinions and recommendations presented hereafter are based on our field tests results and observations of the grading procedure used, and represent our engineering judgment as to the contractor’s compliance with the applicable grading specifications. BACKGROUND INFORMATION Subject property was rough graded in 2017 with our inspection and testing services, with conclusions and recommendation presented in our Rough Grade Compaction Report, dated March 28, 2017 (P.N. 16-011.C). Rough grading operation prepared the site for a building pad ready for construction. House construction began in the middle of 2019 and the construction or site improvements are now completed ready for occupancy. This final report summarized our field inspection and testing services subsequence to the rough grading operation. Scope of work included the subgrade compaction for driveway and street approach, sidewalk subgrade compaction and utility trenches from back of street curb to house. LAKESHORE ENGINEERING August 10, 2020 Project No. PD 16-11.FC Page 2 Our field inspection services for driveway, sidewalk subgrade preparation and utility lateral trenches backfill inspection and utility trench inspection commenced from about March 2 thru June 15, 2020 our last inspection of subgrade for sidewalk. Subgrade preparation was conducted under the supervision of building contractor. FIELD GRADING OBSERVATIONS AND TESTING Subgrade inspection services was done on the as needed basis. Work was accomplished with the help of backhoe and tamper (backhoe attachment and/or vibratory plate) to achieved the required relative compaction. Area of ground was portioned out and completed in stages. During our site visits, subgrade surfaces and trench backfill operation was either completed and/or near completed stages. In general, the work was observed to be conducted in the following manner: 1. The upper 12 inches of driveway subgrade, from face of garages to back of curb was reworked 12” dep and compacted. Due to steepness of driveway pitch, the work was completed in three stages. Subgrade was prepared for support of porous pavers. 2. Bottom of all rework / removal was inspected for competency and deemed competent, before recompacting to desired finished grades. The rework areas extended to the total width of driveway ad shown on grading plan. 3. Approved soils were placed in thin layers, kept in the order of 6 inches, moisture conditioned to near optimum, with each layer compacted to the specified minimum density before adding additional fills. 4. The minimum acceptable degree of relative compaction content was specified at 95 % of the laboratory maximum dry density for subgrade and 90 percent relative compaction for trench backfills. 5. Maximum dry density and optimum moisture content were determined in the laboratory by ASTM D1558- 78, the five layer method. 6. Field density tests were conducted using the sand cone method (ASTM D-1556) and/or the drive tube method (ASTM 2937). 10. The onsite soils encountered were predominantly a dark to medium Brown Silty Clay (CL/CH) mixed with rocks fragments. No import and/or export of dirt was required. 11. All field density test results are listed in the “Summary of Field Density Test Results”, and the test locations are shown on the attached Plot Plan. Also shown are the approximate limits of fill placement under this phase of grading operation. 12. The approximate depth of utility lines are as follows: Water – 18 inches Sewer – 24 inches Electric & Cable – (common) – 30 inches Gas - 18 inches (in common trench) LAKESHORE ENGINEERING August 10, 2020 Project No. PD 16-11.FC Page 3 DEVIATION FROM APPROVED PLANS No deviation from approved plans (DWG No. PD 16-11). Manufactured cut and fill slopes did not show any erosion or distress and in good order. Surface water runoff were made sheetflow away from structure and directed to street drains as per plan. LABORATORY TESTING Laboratory test methods used for fill material were conducted using ASTM D 1557 for moisture – density relationships, optimum moisture content and maximum dry density. ASTM D 4829 foto evaluate Expansion Potential and California Test N0. 417 for Water soluble content. For test results, please refer to Rough Grade Compaction Report, attached in back of this report. Maximum Dry Density and Optimum Moisture Content Determination A representative soil sample was collected from the field and classified under the Uniform Soil Classification System. The soils sample was then tested in accordance with the procedures as outlined in ASTM Method D1557-78, to determine the maximum dry density and optimum moisture content of the particular soil type. The test results are presented below: Soil Type Soil Description Optimum Moisture Content Max. Dry Density A Greyish Silty CLAY (CL/CH) 8.5 % dry wt. 118.0 P.C.F. (rock correction applied) CONCLUSIONS AND RECOMMENDATIONS Based on the results of our field and laboratory test results, on observations of construction procedures used in the field and on our past experience on this kind of work in the area, it is our opinion that entire site grading operation was completed in conformance with the recommendations of the project geotechnical reports (Preliminary, rough grading and this final grading report) and that the onsite fill material used have been placed and compacted in accordance with the project geotechnical reports and the City of Carlsbad Ordinance. SITE DRAINAGE Any future or supplemental grading operation conducted should provide positive drainage around building to minimize water infiltrating into the underlying foundation soils. All drainage should be directly off-site via non- erosive devices such as ditches and/or manufactured swales. Property should be made aware of the potential problems which may develop when drainage is altered through the construction of additional garden walls, pool, patio decking, and gazebos, that are not shown on approved plans. Ponding water situations, leaking irrigation systems, over watering or other conditions which could lead to ground saturation must be avoided. Our findings have been obtained in accordance with accepted professional engineering practices in the field of soil engineering. This warranty is in lieu of all other warranties, either expressed or implied. We sincerely LAKESHORE ENGINEERING August 10, 2020 Project No. PD 16-11.FC Page 3 appreciate the opportunity to be of service. If you have any questions concerning this report or require further information and services, please contact this office at your convenience. Respectfully Submitted, Lakeshore Engineering Fen Yong, RCE 37442 Exp. 6/30/22 Att: Plot Plan, Figure 1 Summary of Field Density Test. Lab. Test Results Attached – Rough Grade Compaction Report SUMMARY □ F FIELD DENSITY TESTS ALEX MANANTAN RESIDENCE 2665 CAZADER□ DRIVE, CARLSBAD ROUGH GRADE COMPACTION REPORT TEST ELEV, MAX, DRY s,c, K,T, DATE LOCATION <FT,) \./ATER DRY RELATIVE ND, DENSITY CONTENT DENSITY REMARKS ASTM ASTM FROM <P.C.F,) COMPACTION NATIVE (1/. DRY \.IT,) (P,C.F,) (1/.) D1558 2937 1 12/16/16 KEY\./AY + 1.0 129,0 16.4 115,8 90,0 O.K. X 2 12/16/16 KEY\./AY + 1.5 129,0 14.4 117,3 91.0 O.K. X 3 12/27 /16 FILL SLOPE + 3,0 129,0 13,6 120.1 93,0 O.K. X 4 12/27 /16 KEY/SLOPE + 3,0 129,0 14,5 117.1 91.0 O.K. X 5 1/11/17 KEY/SLOPE + 5,0 129,0 13,3 116,0 90,0 O.K. X 6 1/18/17 SLOPE +5,0 129,0 15,7 117,0 90,7 O.K. X 7 1/28/17 SLOPE +7,0 129,0 13,8 121.2 94,0 O.K. X 8 1/28/17 DI\./ +6,5 129,0 14.4 119,8 92,8 O.K. X 9 2/12/17 PAD-D/\./ +7,0 129,0 14,0 116,0 90,0 O.K. X 10 2/27 /17 PAD-OVEREX, +2,0 129,0 13,7 116,6 90.4 O.K. X 11 3/14/17 PAD, +4,0 129,0 12,8 117,7 91.2 O.K. X M,C, -MOISTURE CONTENT BY SPEEDY REGENT MARCH 30, 2017 ALL DENSITY TEST ELEV, MEASURED FROM NATIVE BOTTOM PROJECT ND, PD16-11,C PG, 1 □F 1 not to scaleROUGH GRADE COMPACTION REPORTPROPOSED SINGLE FAMILY HOME CONST.2665 CAZADERO DRIVE, CARLSBAD, CA.ALEX MANANTANFIG. 1P.N. PD16-11.CMARCH 30, 2017PREPARED BY: LAKESHORE ENGINEERING27715 JEFFERSON AVE., STE. 113FTEMECULA, CA.PHONE/TEXT: 951-329-6730E: lakeshoreengineering@yahoo.comAPPROX. LIMITS OFFILL PLACEMENTAPPROX. LIMITS OFFILL PLACEMENTLOCATION OF KEYWAYCONSTRUCTIONAPPRO.X LOC. OF FIELDDENSITY TESTAPPRO.X DEPTH OF FILLPLACEMENT.~ ' \ \ EXPLANATION :E I ' If ii: I ! 'I ' ,-I I I ~~. I ~c, B /1. ~ ~ j&l !, \1 ,1§ g I g, < ~ 0 a. /::! w3a X-11 £ ;<( / / ov.4, ' /,,_~~r::,~ <,,,{P \ PLOT PLAN APPENDIX “A” ROUGH GRADE COMPACTION REPORT DATED MARCH 28, 2017 PREPRED FOR Mr. ALEX MANANTAN ROUGH GRADING COMPACTIOON REPORT SINGLE FAMILY HOME CONSTRUCTION MR. ALEX MANANTAN’S RESIDENCE LOT 740, LA COSTA MEADIOWS UNIT 4, MAP NO. 7367 A.P.N. 215-460-02-00 2665 CAZADERO DRIVE CITY OF CARLSBAD COUNTY OF SAN DIEGO, CA. PROJECT NO. PD 16-11.C MARCH 28, 2017 LAKESHORE ENGINEERING LAKESHORE ENGINEERING EST.1987 27715 Jefferson Avenue, Ste. 113F, Temecula, CA. 92590 Phone/Text: (951) 329-6730; Email:lakeshoreengineerin@yahoo.com March 31, 2017 Project No. PD16-11.C Client: Mr. Alex Manantan (760) 271-9464 E:a_manantan@msn.com Attention: City of Carlsbad, Engineering Department, San Deigo County, CA. Subject: Rough Grade Compaction Report (Manantan’s Residence) 2665 Cazadero Drive, Carlsbad, CA. Lot 740, La Costa Meadows Unit 4, map No. 7367 A.P.N. 215-460-02-00; City File No. PD 16-11 Reference: 1. (Preliminary) Limited Geotechnical report Prepared by CE Engineering Consulting Services For Alex Manantan, Dated December 14, 2015 2. Site Grading Plans By CE engineering Consulting Services, 10-scale, PN. PD 16-11 Gentlemen; INTRODUCTION Submitted herewith are the results of our field density tests and observations made during the placement of fill for the construction of a new single family home on the subject property. Periodic field testing and observations were provided by a representative of Lakeshore Engineering to check the grading contractors on compliance with the approved drawing and job grading specifications. The present of our field representative at the site is to provide the property owner a source of professional advice, opinions and recommendations based upon our field observations of the contractor’s work and did not include any supervision, superintending or direction of the actual work of the contractors or the contractor’s workmen. The opinions and recommendations presented hereafter are based on our field tests results and observations of the grading procedure used, and represent our engineering judgment as to the contractor’s compliance with the applicable grading specifications. BACKGROUND INFORMATION AND PROPOSED DEVELOPMENT Subject property is located at 2667 Cazadero Drive, City of Carlsbad, County of San Diego, CA. It is the last two remaining undeveloped lot in the neighborhood. Community appears as an older residential tract, and + 95 % built out, consisting of upper class, custom built, single family homes. Subject lot size is in the order of 0.50 acre, surrounded by single family homes and it fronts Cazadero Drive to the north. It is a berm lot, overall terrain is uphill, gentle sloping, 20 % pitch from front to back, with annual grass ground cover and scattered rocks/boulders. P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 20 FIGURE 1 Vicinity Map riiJ'iiii. CML ENCINEERINC ~c---.-- M, SIC :'IM WL,I.D" mm:l'I, .:::a,~ Pt,11111:;. ('>W) 2A--1111 ~ 01t1J ,n,..a ~t 215417 C:u:a.dero Dr, or Carlsb3d, CA 92009 l { I Figure No. 1 Vicinity Map Imagery ©2017 Google, Map data ©2017 Google 100 ft Page 1 of 1Google Maps 4/3/2017https://www.google.com/maps/@33.1039287,-117.2469628,264m/data=!3m1!1e3 Go gle Maps SETBA C K GRADING PLAN SCALE 1" = 10' B B A Consulting Services SETBACK SETBACKSETBACKC C A D D E E('.) Zo f--w lf! 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II 1 "c Ir ~k\~\ ~ ·• • • ::01 I • "' ,.. z \ --\01 --r; \ WV 2 0 co )> ,0 (E) LWD S . 11-2075 iu>)IE: 415.94 ,tf) ~~- + + + + + + + + + =111- -L/3 ·B"X/6" CONCRETE CURB EDGING AROUND DRIVEWj-1 Y PERIMETER 1~· Hux I /1 -2" BEDDING COURSE (CLEAN SAND) I /1 " THICf<i, PERMEABLE CONCRETE P,j \.£RS (TRAFFIC \ RATED) + + + + + + + + + + + +-------:i= + + + + + + + + + + +---i:' ' " I ' I I I ' I I I ' I I + + + + + + + + + + + + + + + + + + + + + + + + + + + + 1"-~111- o I + + + 1/2-2' ROCK VB-GRADE 5.5" THICK ' I ' ' ' I I I 3/4"-1 1/2" ROCK BASE COURSE 3.5" THICK "" ~ 0 ~ CP. ft\. i i fl -\ • i SECTION D-D PERMEABLE PAVEMENT NOTTO SCALE ~ s ;:;SX, 00 ,0 \ SH Q \ CIVIL ENGINEERING P.O. BOX 2158 VALLEY CENTER, CA 92082 PHONE: (760) 235-1176 FAX: (866) 313-8908 EXIST \ \\ ,£ \ \ ITEMS OF WORK DESCRIPTION G) CONCRETE SIDEWALK (TO BE CONSTRUCTED WITH FUTURE BUILDING PERMIT) 0 CURB OUTLET G) RELOCATE LIGHT FIXTURE AND PULL BOX COORDINATE WITH SERVICE PROVIDER fA\ PCC DRIVEWAY ~ (TO BE CONSTRUCTED WITH FUTURE BUILDING ® PERMEABLE PAVEMENT (BMP STD SD-3) (TO BE CONSTRUCTED WITH FUTURE BUILDING @ VEGETATED SWALE (BMP STD SD-1, SD-3) 0 ROCK SWALE (BMP STD SD-1, SD-3) ® EXISTING WATER SERVICE AND PROPOSED 1" AND BACKFLOW FOR FIRE SPRINKLERS ® EXISTING 4" SEWER LATERAL PERMIT) PERMIT) METER TOE 10' (Min) - 4' FUTURE RESIDENCE 2:J r~-------7 I 21. F.F. 449.□ I .1·_ -_.·-: .... · ·. : _.·." . .-" ... .--_.._.· .. _ .. -_ V~CETATED-SVJLE ~ERMEABLE WALKWAY SEE DETAIL 1 ON SHEET 3 (FUTURE) SECTION E -E BACKYARD GRADING (TYP) NOTTO SCALE ABBREV/A TIONS AB AGGREGATE BASE GV GAS VALVE AC ASPHALT CONCRETE I.E. INVERT ELEVATION A.P.N. ASSESSoR·s PARCEL NUMBER (N) NEW CL CENTER LINE P.L. PROPERTY LINE cov CITY OF \11STA STD. DRAWING P.O.C. POINT OF CONNECTION co SEWER CLEAN OUT pp POWER POLE DWY DRIVEWAY p FINISH PA \IEMENT ELEVATION EL ELEVATION R/W RIGHT OF WAY EP EDGE OF PA \IEMENT SDRSD SAN DIEGO REGIONAL STD. DRAWING EX. EXISTING SWH SEWER MANHOLE F.F. FINISHED FLOOR TC TOP OF CURB ELEVATION F.H. FIRE HYDRANT KM WATER METER FL FLOW LINE WV WATER VALVE FS FINISHED SURFACE IMPERMEABLE & PERMEABLE AREAS CALCULATION DRAWING NO. SDRSD G-7 SDRSD D-25 SDRSD G-14A DETAIL 3 ON SHEET 3 DETAIL 1 ON SHEET 3 DETAIL 2 ON SHEET 3 NO. OJ [I] m [I] DESCRIPTION AREA (SF) SURFACE TYPE BUILDING 4,155 IMPERMEABLE SIDEWALK 650 IMPERMEABLE TOTAL 4,805 DRIVEWAY 2,045 PERMEABLE WAL'rW'JAYS 600 PERMEABLE 11 AS BUILT" RCE __ _ EXP, ___ _ DATE REVIE'v/ED BY, INSPECTOR DATE ~ CITY OF CARLSBAD ISHEETSI 1-1 ---+-1---+-1-------------+1--1>-----11--1-1 ---11 ~ ENGINEERING DEPARTMENT 5 1 GRADING PLANS FOR: I MANANTAN RESIDENCE 2665 CAZADERO DRIVE GRADING PLAN PD16-11 APPROVED: JASON S. GELDERT 17/2/20161 MAL l/1\ REVISED ITEMS OF WORK. MODIFIED DRIVEWAY, ADDED I jCITY ENGINEER RCE 63912 EXPIRES 9/30/18 DATE I ' I I BLDG INFORMATION. I OWN BY: SB I PROJECT NO, I DRAWING N0.1 DA TE I INITIAL ENGINEER OF WORK DATE INITIAL DATE INITIAL CHKD BY: REVISION DESCRIPTION I OTHER APPROVAL CITY APPROVAL RVWD BY: HMP 16-03 493-9A LAKESHORE ENGINEERING March 30, 2017 Project No. PD 16-11.C Page 2 Rough grading operation commenced on December 14, 2016 with operation continuing intermittently as weather and soil conditions permitted, with rough grading operation completed on March 28, 2017, the last day of our site inspection made. Hired grading contractor was Mr. Stuart Harmon form Harmon Excavating and Grading (909) 721 -7350, from Murrieta, CA. The site is planned for a single family home, and rough grading operation resulted in the construction of a level house pad, about centered on the lot, pad now ready for house construction. Manufactured fill slopes are in the order of less than 16 feet high pitched at 2:1/H:V or flatter. Cut slopes are in the order of 15 feet high, also pitched at 21/H:V or flatter. The grading was conducted in conformance with approved plans with no major deviations noted in the field. Proposed house construction is of conventional design, two story, wood frame and stucco walls, supporting a tile roof, founded on conventional concrete spread footings. FIELD GRADING OBSERVATIONS AND TESTING Grading operation commenced and stretched over an approximate 2 ½ months period, commencing middle of December 2016 and with rough grading concluding in early March, 2017, with house pad ready for construction. Grading operation conducted by Stuart Harmon, using a JD200 Excavator, D-4 dozer, backhoe, Rock breaker and haul trucks. Moisture was available from hydrant located at front of property. In general, the rough grading operation was observed to be conducted in the following manner: 1. Surface vegetation, organics, and miscellaneous debris were removed-cleared from the areas to be graded or within the defined limits of grading construction. 2. Unsuitable topsoil within the entire proposed pad area was removed to competent ground before fill placed was made. Toe of slopes keyways were constructed (min. 15’W X 3” D typical ), bottom inspected for sufficient width and depth and deem competent/suitable for its use, prior to fill slope construction. . 3. Unsatisfactory soils (compressible topsoil and oversize rock/boulders) were excavated or removed to exposed competent subgrade (Eocene Santiago Formation underlying at this site) on which to start the fill placement. After achieving pad grade, over-excavation of building pad was removed to 48 inches or 4 feet below pad grade and re-compacted. Over-excavation limits extended 5 feet beyond building footprint. 4. The native soils at bottom of soil over-excavation removal were inspected and deemed competent prior to fill dirt placement. Where applicable, exposed ground soils were scarified (exposed bottom ripped) another 6" in depth, moisture conditioned to near optimum and then re-compacted to minimum standards. 5. Approved soils were placed in thin layers, kept in the order of 1 foot thickness for each layer, with each layer compacted to the specified minimum density before adding additional fills. 6. The minimum acceptable degree of relative compaction content was specified at 90 % of the laboratory maximum dry density. LAKESHORE ENGINEERING March 30, 2017 Project No. PD 16-11.C Page Three 7. Maximum dry density and optimum moisture content were determined in the laboratory by ASTM D1558- 78, the five layer method. 8. Field density tests were conducted suing the sand cone method (ASTM D-1556) and the drive tube method (ASTM 2937). Field testing were made during the placement of fill to determine the degree of compaction and moisture content. 10. The onsite soils encountered were predominantly a dark to medium Brown Silty Clay (CL/CH) mixed with rock fragments. Oversized boulders and/or rock chunks were hauled off to local dump site. 11. All field density test results are listed in the “Summary of Field Density Test Results”, and the test locations are shown on the attached Plot Plan. Also shown are the approximate limits of fill placement under this phase of grading operation. 12. Oversized boulder/rocks, in the order of 250-300 cubic yards were hauled off to local landfill. DEVIATION FROM APPROVED PLANS At the near conclusion of rough grading operation, no major deviation were noted in the field when compared from approved grading plans on-file, DWG No. PD 16-11. Manufactured fill and cut slopes are in the order of 16 feet or less and pitched at 2:1/H:V or flatter. EXISTING FILL SLOPE (STABILITY AND EROSION CONTROL) Fill and cut slopes constructed is in the order of less than 16 feet high respectively, pitched at 2:1/H:V or flatter. The slopes are ready for groundcover/stabilization. Onsite slopes are in our opinion considered to be grossly stable. However, the surface soils consist of a mix of clay, silt and rock fragments considered sensitive to weathering over the passage of time. In order to mitigate slope surface erosion, the following recommendations are presented for consideration, and should be incorporated into the landscape plan for subject site. 1. Slopes should be planted and ground covered as soon as possible with vegetation which is drought resistant and whose root system extends a minimum of 18 inches into the slope face. Immediate planting of the slope is particularly important where bare ground is exposed, to mitigate surface soil creep. 2. Based on experience, high water content in the slope soils is a major cause of slope erosion or slope failures. Vegetation watering should be such that a uniform near optimum content is maintained year round. A landscape architect should be consulted in this regard. Excavations for shrub and/or tree roots placement should be minimized in size so that water will not collect and cause saturation of the surficial soils. Also back cuts for tree wells are geotechnically inadvisable because they create a localized over-steepening condition. LAKESHORE ENGINEERING March 30, 2017 Project No. PD 16-11.C Page Four 3. Excavated slope and footing soils should not be spread loosely on the slope face. Burrowing animals should be controlled because burrows become avenue for water penetration. 4. All slope berms should be regularly maintained. Surface drains should be kept free of debris and in good working order at all time. 5. Seemingly insignificant factors such as human trespass, small concentration of uncontrolled surface water, or poor compaction of trench backfill on slope can result in major erosion. LABORATORY TESTING Maximum Dry Density and Optimum Moisture Content Determination A representative soil sample was collected from the field and classified under the Uniform Soil Classification System. The soils sample was then tested in accordance with the procedures as outlined in ASTM Method D1557-78, to determine the maximum dry density and optimum moisture content of the particular soil type. The test results are presented below: Soil Type Soil Description Optimum Moisture Content Max. Dry Density A Med. Brown Silty CLAY (CL/CH) 8.5 % dry wt. 129.0 P.C.F. w/rock fragments. Expansion Index Test A representative soil sample was tested in the laboratory in accordance with A.S.C.E. Expansion Index Test Method as specified by U.B.C. guidelines. The degree of expansion potential was evaluated from measured soil volume changes obtained during soil moisture alteration. The test results are presented below: Sample Location Depth Soil Description Expansion Index Expansion Potential House Pad F.G. Silty Cl;ay (CL) 93 VERY HIGH Corrosion Suite. Test results are attached in the back of report. Sulphate content is 80< 150 ppm and Concrete Portland Cement Type 11 may be used. LAKESHORE ENGINEERING March 30, 2017 Project No. PD16-11.C Page Five CONCLUSIONS AND RECOMMENDATIONS Based on the results of our field and laboratory test results, on observations of construction procedures used in the field and on our past experience on this kind of work in the area, it is our opinion that the prepared building pad as shown on attached Plot Plan exhibit, is now suitable for support of a single family home construction. FOUNDATION AND FOOTINGS The local soils are considered to be VERY HIGH in expansion potential, with an E.I index of 93 or >91. The building construction may be supported on conventional spread footings. Recommendation for foundation and/or footing construction as provided in the Preliminary Investigation Report, prepared by EC Engineering Consulting Services, Dated December 14, 2015, remains applicable, unless superseded hereon below in this report. For easy reference, the applicable foundation recommendation section of the preliminary soil report are reproduce and attached and appendix in this report. FOUNDATION SETTLEMENT Compacted fill dirt placed under building footprints are in the order of 2 1/2 to 6 feet maximum fill thickness, limits as shown on Plot Plan exhibit. The underlying bedrock soils (Eocene Santiago Formation) is considered competent dense/massive soil. Based on the above recommended design loads, differential settlement should be in the order of less than ½ inch over a span of 50 feet, considered typical and within tolerable limits. 2013 CBC - SEISMIC PARAMETERS Please refer to Preliminary Investigation Report By CE Engineering, under Seismic Parameters for Structural design, pages 11 & 12, appendices in this report. RECOMMENDED FOOTING TRENCH DEPTHS AND TRENCH EXCAVATION INSPECTION Due to the very high expansive nature of the subgrade bearing soils at this site, footings are recommended to be 24 inches for the 2 story construction. Width of footings are recommended to be 16 inches for proposed two- story building construction. All footing trench excavation should be inspected for competency of footing soils for its intended use where applicable, meeting slope face setback requirements. Footing trench inspection should be conducted prior to placement of wooden form setup, steel rebar installation and/or concrete pour. CONCRETE SLAB-ON-GRADE Then local soils are of silt/clay and sand mix, considered to be VERY HIGH in expansion potential (E.I. > 91). Concrete slab (Type 11, Sulphate 80 ppm.) should be design in accordance with 2013 CBC guidelines for the very high expansive soil condition. LAKESHORE ENGINEERING APPENDIX “A” LABORATORY TESTING RESULTS APPENDIX “B” REFERENCE GEO. INVESTIGATION REPORT FOUNDATION REC. SECTION OF SOILS REPORT BY EC ENGR., DATED DEC. 14, 20 P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 10 DISCUSSIONS AND CONCLUSIONS The following conclusions and recommendations are based on the field investigation conducted by our firm, our laboratory test results, and our experience with similar soils in San Diego County. The opinions, conclusions, and recommendations presented in this report are contingent upon CECS being retained to review the final plans and specifications as they are developed and to observe the site earthwork and installation of foundations. The site is underlain by the Santiago Peak Volcanics that consist of very hard, generally highly fractured volcanic rocks. Cutting and grading in relatively fresh rocks will likely require heavy equipment with rippers. There is also the possibility of the need for blasting. The soil on top consists of a small layer of approximately 6 to 8 inches of silty sand dark brown loose soil with a few roots. This material may be potentially compressible and are considered unsuitable for the support of the proposed building loads or additional fill loads in their current condition. In addition, results of our Expansion Index laboratory testing of the upper soils indicate a high expansion potential for the clay encountered. Therefore, these materials should also be completely removed where encountered to a minimum of 24-inches below the bottom of the proposed foundation (whichever is deeper) and replaced with competent compacted fill. The base of the removal areas should be level to avoid differential fill thicknesses under the proposed improvements. This remedial earthwork should extend at least five feet outside the proposed building limits and/or five feet beyond the area to receive fill. After removal of the upper soils and observation of the excavation bottoms, the over-excavated areas should be scarified to a minimum depth of 8-inches, moisture conditioned as needed to achieve at least optimum moisture content and re-compacted to at least 90 percent of the maximum dry density (ASTM D 1557). The over-excavated areas should then be backfilled with imported soils and compacted as recommended herein until design finish grades are reached. Refer to the section below for additional recommendations. RECOMMENDATIONS AND DESIGN PARAMETERS General The proposed construction is considered feasible from a geotechnical standpoint. Grading and foundation plans should take into account the appropriate geotechnical features of the site, and the recommendations of this report. In addition, good design and construction practices should be followed. Assuming all these take place, the proposed addition is not anticipated to adversely impact adjacent properties from a geotechnical standpoint. The recommendations presented herein should be incorporated into the planning and design phases of development. Guidelines for site preparation, earthwork, and onsite improvements are provided in the following sections and in the general grading specifications in Appendix D. All earthwork construction, material removal, excavations, fill placement, as well as general grading procedures should be observed and be selectively tested as required by our firm or designated consultant. The recommendations presented herein have been completed using the information CIVIL ENCINEERINC Consulting Services P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 11 provided to our firm regarding the site development. If information concerning the proposed development is revised, or any changes in the design and location of the proposed property improvements are made, the conclusions and recommendations contained in this report should not be considered applicable unless the changes are reviewed and conclusions of this report modified or approved in writing by our firm. If any unusual or unexpected conditions are exposed in the field, they should be reviewed by the geotechnical consultant, and if warranted, modified and/or additional remedial recommendations will be offered. Specific guidelines and comments pertinent to the planned development are provided herein and in Appendix D. Seismic Parameters for Structural Design Seismic considerations that may be used for structural design at the site include the following (See Appendix C): Ground Motion The proposed addition should be designed and constructed to resist the effects of seismic ground motions as provided in Section 1613 of the 2013 California Building Code. Site Address: 2667 Cazadero Drive, Carlsbad, California Latitude: 33.10383°N Longitude: 117.24669°W Spectral Response Accelerations Using the location of the property and data obtained from the USGS Earthquake Hazard Program (Reference 11), short period Spectral Response Accelerations Ss (0.2 second period) and Sl (1.0 second period) are: Ss = 1.033g Sl = 0.400g Site Class In accordance with Chapter 20 of ASCE 7-10 and the underlying geologic conditions, a Site Class D is considered appropriate for the subject property. Site Coefficients Fa and Fv In accordance with Table 1613.3.3 and considering the values of Ss and Sl, Site Coefficients are: Fa = 1.087 Fv = 1.600 CIVIL ENCINEERINC Consulting Services P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 12 Spectral Response Acceleration Parameters Sms and Sml In accordance with Section 1613.3.3 and considering the values of Ss and Sl and Fa and Fv, Spectral Response Acceleration Parameters for Maximum Considered Earthquake are: Sms = (Fa)(Ss) = 1.123g Sml = (Fv)(Sl) = 0.640g Design Spectral Response Acceleration Parameters Sds and Sdl In accordance with Section 1613.3.3 and considering the values of Sms and Sml, Design Spectral Response Acceleration Parameters for Maximum Considered Earthquake are: Sds = 2/3 Sms = 0.748g Sdl = 2/3 Sml = 0.427g Long Period Transition Period A Long Period Transition Period of TL = 8 seconds is provided for use in San Diego County. Seismic Design Category In accordance with Tables 1604.5 and 1613.3.5, and ASCE 7-10, a Risk Category II and a Seismic Design Category D are considered appropriate for the subject property. Lateral Loads: Lateral load resistance for the structures supported on footing foundations may be developed in friction between the foundation bottoms and the supporting subgrade. An allowable friction coefficient of 0.35 is considered applicable. An additional allowable passive resistance equal to an equivalent fluid weight of 300 pcf acting against the foundations may be used in design provided the footings are poured neat against the adjacent properly compacted fill or dense formational materials. These lateral resistance values assume a level surface in front of the footing for a minimum distance of three times the embedment depth of the footing and any shear keys. Settlement Settlements under building loads are expected to be within tolerable limits for the proposed structure. For footings designed in accordance with the recommendations presented in the preceding paragraphs, we anticipate that total settlements should not exceed 1 inch and that post- construction differential angular rotation should be less than 1/240. Foundation Recommendations CIVIL ENCINEERINC Consulting Services P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 13 The proposed addition may be supported on conventional continuous and spread footings with a minimum of at least 18-inches below lowest adjacent grade and bearing on competent material. Continuous footings should be at least 12-inches wide and reinforced with a minimum of four #5 bars, two at the top and two at the bottom of the footing. A minimum clearance of 3 inches should be maintained between steel reinforcement and the bottom or sides of the footing. We recommend that the proposed new building and garages be supported on conventional, continuous and/or isolated footing foundations bearing on compacted fill soils prepared as recommended below and the grading specifications in Appendix D. Foundations bearing as recommended may be designed for a dead plus live load earing value of 2,000 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 and a coefficient of friction between foundation and soil and concrete of 0.35 may be assumed. These values assume that footings will be poured neat against the exposed soil. Footing excavations should be observed by this firm prior to the placement of reinforcing steel in order to verify that they are founded in suitable bearing materials. Slab on Grade Recommendations Slabs on grade for the proposed building should have a minimum thickness of 5 inches and should be reinforced with #4 bars spaced at 18 inches, on center, both ways, placed at mid-height in the slab. Floor slabs should be underlain with a moisture vapor retarder consisting of a 10-mil polyvinyl chloride 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 accordance with ASTM B 1643. Prior to placing concrete, the slab subgrade soils should be thoroughly moistened. Slab subgrade soil should be verified by our firm representative to have the proper moisture content within 48 hours prior to placement of the vapor barrier and pouring of concrete. Total and differential settlement due to foundation loads is expected to be less than ¾-inch and 3/8-inch, respectively, for footings founded as recommended. Minor differential movement and resulting damage may occur and should be considered by the Architect in the design. It is noted that floor slabs occasionally crack for various reasons, causing brittle surfaces such as ceramic tiles to become damaged. Following placement of any concrete floor slabs, sufficient drying time must be allowed prior to placement of floor coverings. Premature placement of floor coverings may result in degradation of adhesive materials and loosening of the finish floor materials. Concrete Isolation Joints CIVIL ENCINEERINC Consulting Services P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 14 We recommend the project Civil Structural Designer/Structural Engineer incorporate isolation joints and saw-cuts to at least ¼ the thickness of the slab in any floor designs. The joints and cuts, if properly placed, should reduce the potential for and help control floor slab cracking. We recommend that concrete shrinkage joints be spaced no farther than approximately 20 feet apart, and also at re-entrant corners. However, due to a number of reasons (such as base preparation, construction techniques, curing procedures, and normal shrinkage of concrete), some cracking of slabs can be expected. Exterior Slab Reinforcement As a minimum for protection of on-site improvements, we recommend that all exterior pedestrian concrete slabs be founded on properly compacted and tested fill, with No. 3 bars at 18-inch centers, both ways, at the center of the slab, and contain adequate isolation and control joints. The performance of on-site improvements can be greatly affected by soil base preparation and the quality of construction. It is, therefore, important that all improvements are properly designed and constructed for the existing soil conditions. The improvements should not be built on loose soils or fills placed without our observation and testing. For exterior slabs with the minimum shrinkage reinforcement, control joints should be placed at spaces no farther than 15 feet apart or the width of the slab, whichever is less, and also at re-entrant corners. Control joints in exterior slabs should be sealed with elastomeric joint sealant. The sealant should be inspected every 6 months and be properly maintained. Concrete Pavement We recommend that concrete driveway pavements, including the garage slab, subject only to automobile and light truck traffic be 5 inches thick and be supported directly on properly prepared/compacted on-site subgrade soils. The concrete for driveways and exterior parking areas to include fire access should have a minimum thickness of 6 inches. The upper 12 inches of the subgrade below the slab should be compacted to a minimum degree of compaction of 95 percent just prior to concrete placement evaluated in accordance with ASTM D 1557. The concrete should be commercially available concrete for driveways and designed for not less that 2,500 psi in 28 days. In order to control shrinkage cracking, we recommend that saw-cut weakened-plane joints be provided at about 15-foot centers both ways and at re-entrant corners. The placement slabs should be saw-cut as soon as practical, but no more than 24 hours after the placement of the concrete. The depth of the joint should be ¼ of the slab thickness and its width should not exceed 0.02-feet. Reinforcing steel is not necessary unless it is desired to increase the joint spacing recommended above. Control and isolation joints shall be sealed with elastomeric joint seal. Asphalt Concrete Pavement CIVIL ENCINEERINC Consulting Services P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 15 We recommend a commercial asphalt concrete (AC) mix. The minimum structural section should be 4 inches of AC over 6” of properly compacted class 2. The class 2 shall be compacted to a minimum compaction of 95%. The upper 12 inches of the subgrade below the slab should be compacted to a minimum degree of compaction of 95 percent just prior to AC placement evaluated in accordance with ASTM D 1557. Preparation of Soils for Site Development/Site Grading Clearing and Grubbing Vegetation and miscellaneous debris should be removed and disposed offsite to the nearby disposal area. Holes resulting from the removal of buried obstructions or other improvements, which extend below finished site grades, should be replaced with compacted fill or slurry. In the event that abandoned septic tanks, or storage tanks are discovered during the excavation, they should be removed and backfilled in accordance with city regulations. Existing utility lines to be abandoned, if any, should be removed and capped in accordance with local requirements. Removal and Re-compaction of Existing Topsoil and Weathered Formation Soils In order to provide suitable support for the proposed new building and associated improvements such as decking, sidewalks, and driveways, we recommend that all existing topsoil and weathered formation soils be removed and replaced with structural fill compacted to a minimum degree of compaction of 90 percent for the building and 95 percent for the driveways. The limits of re-compaction should extend at least 10 feet beyond the perimeter limits of all new improvements. The re-compaction work should consist of: (a) removing all existing topsoil and weathered soils down to the underlying undisturbed formational materials including any expansive clay soils; (b) scarifying, moisture conditioning, and compacting the exposed natural subgrade soils; and (c) replacing the materials as compacted structural fill. The extent and depths required to be removed include the existing topsoil and weathered/fractures soils should be determined by our firm representative during the excavation work based on his examination of the soils being exposed. Subgrade Preparation and Scarification After the site has been cleared, stripped, and the required excavations made, the exposed subgrade soils should be scarified to a minimum depth of 6 to 8 inches, brought to near optimum moisture content, and compacted to at least 90-percent relative compaction based upon ASTM D 1557. Material for Fill All on-site soils with an organic content of less than 3 percent by volume are in general suitable for reuse as fill. Any required imported fill material should be a low-expansive granular soil. In addition, all fill material should not contain rocks or lumps over 6 inches in greatest dimension, not more than 15 percent larger than 2½ inches, organic debris, and other deleterious materials. CIVIL ENCINEERINC Consulting Services P.O. Box 2158 Valley Center, CA 92082 Phone: (760) 271-8261 Fax: (866) 313-8908 Email: marco@engineeringconsulting.us 39 APPENDIX F Laboratory Test Data CIVIL ENGINEERING Consult ing Serv ices PIT :  DEPTH CALCULATED BY: DBJ SOIL DESCRIPTION TESTED BY DBJ CLIENT :LOCATION  TEST DATE : 2667 CAZADERO DRIVE , CARLSBARD CA.  GROUND ELEVATION 469 ft ASTM D 4829  Test Method for Expansion Index of Soils  B‐1 SAMPLE : C-2 @ 4 ft 1" 4 ft 1" ML 12/5/2015 I ~ CIVll ENCINEERINC I I Consulting Services I I I I I I EX.PANTIO N INDEX '93 DRY DENSITY ( P·CF) 118 M O IS:fER CONTENT (%) 13 EXPANSION INDEX EXPAN SION POTEN CIA L 0-2:0 VERY LOW 21-50 LOW 51-'90 MEDIUM 91-130 HIGH PIT :  DEPTH CALCULATED BY: DBJ SOIL DESCRIPTION TESTED BY DBJ CLIENT :LOCATION  TEST DATE : 2667 CAZADERO DRIVE , CARLSBARD CA.  GROUND ELEVATION B‐1 SAMPLE : C-1 @ 5 ft 4" 5 ft 4" CH 12/5/2015 469 ft LABORATORY COMPACTION   ASTM D‐698 I ~ CIVIL ENGINEERING I Con sulllng Services I I I I I 140 130 \ I\ I ' • ,, -120 --7 <.J C. ... -'\ > I'\ I-I\ en 110 z w C > c::: 100 C 90 5 10 15 ~MOISTURE25 30 35 40 MOISTURE CONTENT (%) -11% - MAXIMUM DENSITY 125 pcf SAMPLE MOLD(IW) MOLD 8t WET SOIL (IW) WCTSOIL(IW) MOISTURE WETDENSIT'l'(pd) DR'r' DENSITY (pd) 1 4.35 8.73 4.38 9.5 131.40 120 2 4.35 9.00 4.65 10.7 139.50 126 3 4.35 8.87 4.52 10.2 135.60 123 4 4.35 8.83 4.48 14.9 134.40 117 CLASSIFICATION OF FINE-GRAINED PORTION OF SOIL= • SIL TS AND CLAYS ( LIQUID LI MIT 50% OR GREATER PIT :  DEPTH CALCULATED BY: DBJ SOIL DESCRIPTION TESTED BY DBJ CLIENT :LOCATION  TEST DATE : 2667 CAZADERO DRIVE , CARLSBARD CA.  GROUND ELEVATION 469 ft LABORATORY COMPACTION   ASTM D‐698 12/5/2015 B‐1 SAMPLE : C-2 @ 4 ft 1" 4 ft 1" ML I ~ CIVIL ENGIN EERIN G I Consulting Services I I I I 140 " V 130 Iii. ~ ~ ' .. .. -120 I'-. -' <.> C. ' -r----.. > 1"-- I-' en 110 ' z r----.. w C > c::: 100 C 90 5 10 15 ,J'MOISTURE 25 30 35 40 MOISTURE CONTENT (%) -8.2% M AXIMUM DENSITY 1.2'9 pcf WET DENSITY (r>d ORV DENSITY (pd SAMPLE MOLD(II,.,-) MOLD & WET SOIL (IN) WETSOIL(ll.r) MOISTURE ) ) 1 4.35 8.73 4.15 5.5 131 125 2 4.35 9.00 4.30 8.1 140 129 3 4.35 8.95 4.10 12.2 138 123 4 4.35 8.90 3.93 15.8 137 118 CLASSIFICATION OF FINE-GRAINED PORTION OF SOIL= -INORGANIC SILTS AND VERY FINE SANDS, ROOK FLOUR, SIL TY OF CLAYED FINE SANDS OR CLAYED SOL TS WITH SLIGHT PLASTICITY