BOARD OF

BUILDING AND SAFETYCOMMISSIONERS

VAN AMBATIELOSPRESIDENT

E. FELICIA BRANNONVICE·PRESIDENT

JOSELYN GEAGA-ROSENTHALGEORGE HOVAGUIMIAN

JAVIER NUNEZ

CITY OF Los ANGELESCALIFORNIA

ERIC GARCETTIMAYOR

~TRANSMiTTAL NO. 0

DEPARTMENT OF

BUILDING AND SAFETY201 NORT II FIGUEflOA STnI', ,­

LOS ANGELES, CA 90()\;;

RAYMOND S. CHAN, C.E.. t.GfNERAL MANAGER

FRANK BUSHEX£CUTIVE OFFICER

GEOLOGY AND SOILS REPORT APPROVAL LETTER

November 25, 2015LOG # 81567-03SOILS/GEOLOGY FILE - ~

LANGoran Bilaver4430 Rosebank Ave.La Canada, CA 91011

TRACT:LOT(S):LOCATION:

1000PT I I 11 (Arb-28)3961 N. Oeste Avenue

CURRENT REFERENCEREPORT/LETTER(S)Addendum ReportOversized Doc(s).

PREVIOUS REFERENCEREPORT/LETTER(S)Dept. Correction LetterAddendum ReportDept. Correction LetterGeology ReportDept. Correction LetterGeology/Soils ReportSoils Lab Testing Report

REPORTNo.SG 8045-W

REPORTNo.81567-02SG 8045-W81567-01SG 8045-W81567SG 8045-WCYG-13-6807

DATE(S) OFDOCUMENT10/08/2015

DATE(S) OFDOCUMENT08/14/201505/07/201503/27/201502/191201510/30/201308/26/201307/0112013

PREPARED BYSchick Geotechnical. Inc

PREPARED BYLADBSSchick Geotechnicril. Inc.LADBSSchick Geotechnical. Inc.LADBSSchick Geotechnical. Inc.C. Y. Geotcch. lnc.

The current referenced report by Schick Geotechnical, Inc. (Schick) 'concerning the proposedconstruction of a three-level single-family residence and retaining walls has been reviewcd by thcGrading Division of the Department of Building and Safety. According to the currcnt and previousreports by Schick, the proposed residence is situated on an east facing ascending 1.5: 1(/-I:V) slopc. Clltinto the toe ofslope and stepping up multiple levels. Based on the included topographic map. howc\'cr.there is also a north/northeast-facing slope along the north edge of the site with a I: 1 gradient.

The earth materials at the subsurface exploration locations consist of up to 3 feet of uncertified fiJIunderlain by soil and Modelo Formation bedrock. Bedding within the Modelo Formation is reportedto dip steeply to the south (although bedding appears to be inadvertently shown as north dipping on theincll:!ded map).

The reports recommend trimming the east-facing slope to a gradient of2: 1(H:V) using retaining walls.

lADllS G-S {RlJ\t 00J05I20141 AN EQUAL EMPLOYMENT OPPORTUNITY - AFFIRMATIVE ACTION EMPLOYER

Page 23961 N. Oeste Avenue

Pile foundations are recommended for the retaining walls. Conventional foundations (partiallydeepened) are recommended to the residential structure, which will incorporate a rear retaining wallabout 24 feet high. The upper part ofthis wall is to be backfilled to create a 15-ft. flat area between thestructure and the ascending slope.

The site is located in a designated seismically induced landslide hazard zone as shown on the "SeismicHazard Zones" map issuedbythe StateofCalifomia. Theslopestabilityanalyses included in the reportsindicate that factors ofsafety are less than the minimmn code requirements for both static and seismicconditions. To achieve code required factor ofsafety, two rows ofslope stabilization piles are proposed,therefore, the requirements of the 2014 City ofLos Angeles Building Code, have been satisfied.

The referenced reports are acceptable, provided the following conditions are complied with during sitedevelopment:

(Note: Numbers in parenthesis ( ) refer to applicable sections ofthe 2014 City of LA BuiIding Code.PIBC numbers refer the applicable Information Bulletin. Infonnation Bulletins can be accessed on theinternet at LADBS.ORO.)

I. The geologist and soils engineer shall review and approve the detailed plans prior to issuanceof any permits. This approval shall be by signature on the plans that clearly indicates thegeologist and soils engineer have reviewed the plans prepared by the design engineer and thatthe plans include the recommendations contained in their reports. (7006.1)

2. All recommendations of the report{s) that are in addition to or more restrictive than theconditions contained herein shall be incorporated into the plans.

3. A copy of the subject and appropriate referenced reports and this approval letter shall beattached to the District office and field set ofplans. Submit one copy of the above reports tothe Building Department Plan Checker prior to issuance ofthe permit. (7006.1)

4. A grading permit shall be obtained. (106.1.2)

5. All graded, brushed or bare slopes shall be planted with low-water consumption. native-typeplant varieties to protect slopes against erosion. (7012)

6. All new graded slopes shall be no steeper than 2H:IV (7010.2 & 7011.2).

7. Prior to the issuance of any permit, an accurate volume detennination shall be made andincluded in the final plans, with regard to the amount of earth material to be exported from thesite. For grading involving import or export ofmore than 1000 cubic yards ofearth materialswithin the grading hillside area, approval is required by the Board of Building and Safety.Application for approval of the haul route must be filed with the Grading Division. Processingtime for application is approximately 8 weeks to hearing plus lo-day appeal period.

8. All man-made fill shall be compacted to a minimwn 90 percent ofthe maximum dry density ofthe fill material perthe latestversionofASTM D 1557. Where cohesionless soil having less than15 percent finer than 0.005 millimeters is used for fill, it shall be compacted to a minimum of95 percent relative compaction based on maximum dry density (D1556). Placement ofgravelin lieu of compacted fill is allowed only ~f complying with Section 91.7011.3 of the Code.(7011.3)

Page 33961 N. Oeste Avenue

9. Existing uncertified fill shall not be used for support of footings, concrete slabs or new fill.(1809.2)

10, Drainage in ronformance with the provisions of the Code shaH be maintained during andsubsequent to construction. (7013.12)

1,1. The applicant is advised that the approval of this report does not waive the requirements forexcavationscontained in the State Construction SafetyOrdersenforced by the State Division ofIndustrial Safety. (3301.1)

12. Excavations shall not remove lateral support from a public way, adjacent property or an existingstructure. Note: Lateral support shall be considered to be removed when the excavation extendsbelow a plane projected downward at an angle of45 degrees from the bottom ofa footing ofanexisting structure, from the edge of the public way or an adjacent property. (3307.3.1)

13. Prior to the issuance ofany permit which authorizes an excavation where the excavation is tobe ofa greater depth than are the walls or foundation ofany adjoining building or structure andlocated closerto the property line than the depthofthe excavation, the owner ofthe subject siteshall provide the Department with evidence that the adjacent property owner has been given a30-day written notice ofsuch intent to make an excavation. (3307.1)

14. The soils engineer shaH review and approve the shoring plans prior to issuance of the permit.(3307.3.2)

15. Prior to the issuance of the permits, the soils engineer and/or the structural designer shallevaluate the surcharge loads used in the report calculations for the design ofthe retaining wallsand shoring. If the surcharge loads used in the calculations do not conform to the actualsurcharge loads, the soil engineer shall submit a supplementary report with revisedrecommendations to the Department for approval.

16. Unsurcharged temporary excavations shall be performed as specified on page 7 of the0211912015 report.

17. Shoring shall be designed for the lateral earth pressuresspecified in the section regarding soldierpiles starting on page 5 of the 02l19f2015"report; all surcharge loads shaH be included into thedesign.

18. Shoring shall be designed for a m~imum lateral deflection of J inch, provided there are nostructures within a 1:1 plane projected up from the base ofthe excavation. Where a structureis within a 1:1plane projected up from the base of the excavation, shoring shall be designed fora maximum lateral deflection of~ inch, or to a lowerdeflection determined by the consultantthat does not present any potential hazard to the adjacent structure.

19. A shoring monitoring program shall be implemented to the satisfaction of the soils engineer.

20. All foundations shall derive entire support ftom competent bedrock, as recommended andapproved by the geologist and soils engineer by inspection.

21. Foundations adjacent to a descending slope steeper than 3:1 (H:V) in gradient shall be aminimum distance of one-third the vertical height of the slope but need not exceed 40 feetmeasured horizontally from the footing bottom to the face ofthe slope (1808.7.2)[; for pools the

Page 43961 N. Oeste Avenue

foundation setback shall be one-sixth the slope height to a maximum of20 feet (1808.7.3).Where the slope is steeper than 1:I, the required setback shall be measured from an imaginaryplane 45 degrees to the horizontal, projected upward from the toe ofthe slope].

22. Buildings adjacent to ascending slopes steeper than 3:1 (H:V) in gradient shall be set back fromthe toe ofthe slope a level distance equal to one-halfthe vertical height of the slope, but neednot exceed IS feet (1808.7.1) [; for pools the set back shall be one-fourth the vertical height ofthe slope. but need not exceed 7.5 feet (1808.7.3). Where the slope is steeper than 1:1, the toeofthe slope shall be assumed to be at the intersection ofa horizontal plane drawn from the topof the foundation and a plane drawn tangent to the slope at an angle of 45 degrees to thehorizontal].

23. Pile caisson and/or isolated foundation ties are required by Code Sections 1809. I3 and/or1810.3.13. Exceptionsand modification to this requirementare provided in Information BulletinPIBC 2014-030.

24. Two rows ofsoldierpiles shall be used to stabilize the slope, as recommended in the 05/07/2015report.

25. Slope stabilization piles shall be designed for the lateral loads as specified on page 2 of theOS/07flO 15 report.

26. When water over 3 inches in depth ispresent in drilled pile holes. a concrete mix with a strengthof 1000 p.s.i. over the design p.s.i. shall be tremied from the bottom up; an admixture thatreduces the problem ofsegregation ofpastelaggregates and dilution ofpaste shall be included.(1808.8.3)

27. Existing uncertified fill shall not be used for lateral support ofdeep foundation. (1810.2. I)

28. Slab on uncertified fill shall be designed as a stnIctural slab. (7011.3)

29. Slabs placed on approved compacted fill shall be at least 4 inches thick and shall be reinforcedwith Yz-inch diameter (#4) reinforcing bars spaced maximum of 16 inches on center each way.

30. The seismic design shall be based on a Site Class C as recommended. All other seismic designparameters shall be reviewed by LADBS building plan check.

31. Retaining walls shall be designed for the lateral earth pressures specified in the section titled"Retaining Wall Design" starting on page 4 ofthe 0211912015 report. Note: Where two separatestacked retaining walls [the upperwall surcharges the lowerwaJl] are proposed, the lower ofthe2 walls shall be designed for the combined height of the 2 walls. All surcharge loads shall beincluded into the design.

32. Retaining walls at the base ofascending slopes shall be provided with a minimum freeboard of2 feet, as recommended.

33. The recommended equivalent fluid pressure (EFP) for the proposed retaining wall shall applyfrom the top ofthe freeboard to the bottom ofthe wall footing.

34. All retaining walls shall be provided with a standard surface backdrain system and all drainageshall be conducted to the street in an acceptable manner and in a non-erosive device. (70 I 3.1 I)

PageS3961 N. Oeste Avenue

35. With the exception ofretainingwallsdesigned for hydrostatic pressure, all retaining walls shallbe provided with a subdrain system to prevent possible hydrostatic pressure behind the wall.Prior to issuance of any })emit. the retaining wall subdrain system recommended in the soilreport shall be incorporated into the foundation plan which shall be reviewed and approved bythe soils engineer ofrecord. (1805.4)

36. Installation of the subdrain system shall be inspected and approved by the soils engineer ofrecord and the City gradinglbuilding inspector. (108.9)

37. Basement walls and floors shall be waterproofed/damp-proofed with an L.A. City approved"Below-grade"waterproofing/damp-proofingmaterial witha research report number. (104.2.6)

38. Prefabricated drainage composites (Miradrain) (Geotextiles) may be only used in addition totraditionally accepted-methods ofdraining retained earth.

39. The structure shall be connected to the public sewer system. (pIBC 2014-027)

40. All roofand pad drainage shall be conducted to the street in an acceptable manner[; water shallnot be dispersed on to descending slopes without specific approval from the Grading Divisionand the consulting geologist and soils engineer]. (7013.10)

4] . All concentrated drainage shall beconducted in an approved device and disposed of in a mannerapproved by the LADBS. (7013.10)

42. Any recommendations prepared by the geologist and/or the soils engineer for correction ofgeological hazards found during grading shall be submitted to the Grading Division of theDepartment for approval Prior to utilization in the field. (7008.3)

43. The geologist and soils engineer shall inspect all excavations to determine that conditionsanticipated in the report have been encountered and to provide recommendations for thecorrection ofhazards found during grading. (7008 & 1705.6)

44. All friction pile or caisson drilling and installation shall be perfonned under the inspection andapproval of the geologist and soils engineer. The geologist shall indicate the distance thatfriction piles or caissons penetrate into competent bedrock in a written field memorandum.(1803.5.5, 1704.9)

45. Prior to the pouring ofconcrete, a representative of the consulting soils engineer shall inspectand approve the footing excavations. He shall post a notice on the job site for the LADBSBuilding Inspector and the Contractor stating that the work so inspected meets the conditionsof the report, but that no concrete shall be poured until the City Building Inspector has alsoinspected and approved the footing excavations. A written certification to this effect shall befiled with the Grading Division of the Department upon completion of the work. (108.9 &7008.2)

46. Prior to excavation, ail initial inspection shall be called with LADBS Inspector at which timesequence ofconstruction, shoring, pile installation,protection fences and dust and traffic controIwill be scheduled. (108.9.1)

47. Installation ofshoring, underpinning, slot cutting excavations and/or pile installation shall be

Page 6396] N. Oeste Avenue

performed under the inspection and approval ofthe soils engineer and deputy grad ing inspec tor.(1705.6)

48. Prior to the placing of compacted fill, a representative of the soils engineer shall insrect andapprove the bottom excavations. He shall post a notice on the job site for the City GradingInspector and the Contractor stating that the soil inspected meets the conditions of the report,but that no fill shall be placed until the LADBS Grading Inspector has also inspected andapproved the bottom excavations. A written certification to this effect shall be included in thefinal compaction report filed with the Grading Division of the Department. All fill shall beplaced under the inspection and approval of the soils engineer. A compaction report togetherwith the approved soil report and Department approval letter shall be submitted to the GradingDivision of the Department upon completion of the compaction. In addition, an Engineer'sCertificate ofCompliance with the legal description as indicated in the grading permit and the

;{::;~b;;:;:::1.3)

DANIEL C. SCHNEIDEREIT ~Engineering Geologist I Geotechnical Engineer I

Log No. 81567-03213-482-0480

cc: Bert Notch, ApplicantSchick Geotechnical, Inc., Project ConsultantVN District Office