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Home My WebLink About30578 (58)Is N15 TRIAD FOUNDATION't ;1QAA Foundation Engineering * Engineering GeologyiFMaterialTesting # Construction Inspection 17231 EAST RAILROAD STREET, SUITE 100, CITY OF INDUSTRY, CA 91748 TELEPHONE (818) 964-2313 FAX (818) 810-0915 Stin-Ray 1.724 Leaning Pine Diamond Bar, CA 91765 Subject: Supplemental Geotechnical Data and Review of Revised Grading Plan 4ot 36; Tract 30578 I-2ZIO'S"Rim- Fire Lane Diamond Bar, California S Refei,,7ences: 1) Preliminary Soils & Geologic Investigation By Triad Foundation Engineering, Inc. Dated 9-8-88 2) County Geologic Review Sheet dated 11-21-Sw 3) Supplemental Geotechnical Data & Review of Revised Grading Plan By Triad Foundation Engineering, Inc. Dated 3-21-89 4) County Geologic Review Sheet dated 5-19-89 5) County Soils Review Sheet dated 5-18-89 Gentlemen: Additional subsurface exploration was conducted downslope on the site as requested by the County Geologist (Reference #4). The location of the three Test PIts (#2, 3 and 4) and the data obtained are plotted on the attached Geologic Map and Cross Sections. 0 13 dfli.tional geologic data downslope shows a slight steepening of the apparent dip shown on the attached Crass Sections A --A" and B- B.. Stability calculations contained in our Preliminary Report on 'the natural slope indicate it to have an acceptable factor of safety of 1.5. The present grading concept is to place a fill to support the iouse. As drawn on the plan it appears this fill will slope at ars average angle of 30 degrees and will be supported by a crib wall a,s high as 40 feet. As noted on the plan the fill slop will beat 4 gr (1. .1 awall be supported ..,.,fo=: de. ha ci high crib wdll.we presume the latter is, the case. wwill encroach onto the restripted use 4 Roberta • I Associatess ofl 11- as an area of slumping and landsliding. Test Pit #4 indicates the rock to be relatively undisturbed. Test Pit #3 indicates the rocks to be moderately weathered and fractured to bout 4.5 feet. Below this point the rock is slightly weathered and difficult to excavate with little or no fracturing. Based on this data we have repositioned the edge of the area of slumping and, landsliding towards the east (See attached Geologic Map). It appears therefore that much of the east edge of the fill will be outside this affected area. 0 5s qj).j-pjngineer1s Res once The following comments are in response to the soils review, reference S. 1:em I With, the additional field investigation we are no longer relying on previous reports and our reports are adequate for analysis of 1 --he site. Item 2. By others. Item 3. Bedding planes are well suported in the true dip as shown on the enclosed Geologic Map and Cross Sections with the additional field exploration. Additional slope stability calculations with 11311 :ill Hill iiii I Ili Ill ill! I'l I 1ogs are not required. Footings encroaching the compacted fill slope should have a horizontal distance of 7 feet from the bottom side of the footing to 'the face of the compacted fill slope as a minimum. The opportunity to be of service to you on this project is appreciated, and if you have any questions, please call us at your convenience. H= WIMIMN 1* 11 1 OF411rark Faw". 1 RH William G. Uhl C.E.G. 502 WGIJ;FCS/thf Frank C. Stillman G.E. 805 Enclosures: L.A. County Review Sheets Plate A --- Cross Sections Plates B-2 thru B-4 --- Test Pit Logs Geologic Map 0 N /VP 1 2" / GEOLOGIC REVIEW SHEET sheet, of L. A. COUNTY DEPARTMENT OF PUBLIC WORKS goo So. FRE)4ONT AVE., AL RAY CA 91803 LAND DEVELOPMENT DIVISION 1'r )PM . ..... Lot(s) Parent Tiract Location Site Address Sr lei 17'"A't-6 Developer Geologist Soils Engineer Engineer/Arch. Review of'- P I Po Grading P.C.No. Geologic Report(s) Dat Soils Report(s) Dated p. Geology and Soils Repo Dist. office F NF Dist. Engineer Geologist -- Soils Engineer Geo. Sect. File Grading Section Health Dept. Engineer Building P.C. No. For. 74-Plan Is not approved for reasons below. Action: Plan is geologically approved. Submit pl,ans for recheck. Include -a co Plan approved geologically subject of this review and all rtE2.rts- to conditions bel AlWA Remarks: 4;014'14 KVi, te, /4t -1-o "'I ess sign at site. Stake corners of lot wit Site cci ld no dometer mileage from road intersections. highly visib 'I 2, nio apparent geologic hazards, as defined by Los Angeles County, were observed at building site. A geologt ii^°eport should not be required. 3. conply with previous geO441WSOils review sheet(s) dated t--submitted,--40-1044*-t-e-4ew,,s;bmit plans and/or reports. t. )' R e, qu i r e d p I an g-,,iandtaCar-eft0f!t454o acknowledge and filed. 5 T'he reference report(s) is ace ZXfttj6-- 01 incomplete, Resubmit two uricjq nal copies Of alIlsumitedwereelt1hillegibleqincomplete, or both 6. The Qs" geotechnical reports for this project. Reproduced copies are not acceptable. 7, Report(s) can not be reviewed until the plans have been reviewed and approved by the geotechnica consultants, by manual, ori final signatures and dates on each sheet of the plan. 8. N BuildIng Plans can't. be approved until completion of rough grading, and approval by the Geology Section based on the final Geology and soils Report (submit at completion of grading). Do not resubmit buildin I ans. I 1 4 mr.111-22 0", NA AR elf Date P r,epared by A' e -.4 - AO I GEOLOGIC REVIEW SHEET Sheet of L. A. COUNTY DEPARTMENT OF PUBLIC WORKS Dist. Office 900 O. FRE)4ONT AVE., ALHAMBRA, CA 91803 F NF LAND DEVELOPMENT DIVISION r a ct/Pm Lot(s) I Parent 1'ract i.e Address 2 Geologist Soils Engineer Review of: Trading P. C. N. Geologic Report(s) Dated Soils Report(s) Dated Location 4T.M. A Engineer/Arch. DREM-92HIM Dist. Engineer Geologist Soils Engineer 1 Geo. Group Mr. T Grading Section Health De,t. Engineer For: Geology and Soils Report(s) Dated A- Action: Plan is geologically approved. PlaK is not a proved for M..ns below. AS Plan approved geologically subject SUBMIT PLANS FOR RECHECK. Include a c to conditions below. of this review. e Remarks: I 'A consulting, englneering geology, engineerin report( is required which evaluate(s) 0thisspecificplan, and make(s) recommendations. Prepared by A 640 400WEd, Re le ed by Dal - GEOTECHNICAL ENGINEERING REVIEW SHEET COUNTY OF LOS ANGELES District Office 10 Address: 900 So. Fremont Ave. DEPARTMENT OF PUBLIC WORKS Alhambra, CA 91803 Telephone: (818) 458-4925 Land Development Division Sheet 1 of 1 1,j 3 -7V DISTRIBUTION: Proposed Single Family Residence Location 2210,5 Rim Fire Lane, Diamond Bar I Grading and Drainage Sect. Developer' wner 7 o -ch ra n T Geo/Soils Central File Geotechnical Engineer Triad Foundation Engineerin2 Geologist Geologist _ Same as above Geotechnical Engineer Engineer District Engineer Grading Plan Check No. . 0861 Review of: Geotechnical Report dated 3/21/89 Geologic Report dated 3/21/89 Action: IffiffMITI] M-0 1. Provide preliminary soil report dated 9/8/88. 2. ""' Provide grading plans including detail sections of proposed buttress fills, crib walls, and fill benches. 3. Provide slope stability analyses for the out -dipping slopes shown on Sections A -A, and B -BI of the geotechnical report. 4' The Geotechnical Engineer must review the grading plans and sign and stamp the plans in verification of his recommendations and the recommendations of the approved geotechnical report. Mr1=1 The Geotechnical Engineer shall inspect and approve the foundation excavations before steel or concrete is placed. 6. Please include a copy of this review sheet with your response. Prepared by Paul Chang F':0859 Reviewed by 4 e d-4ateeKt4at 5/18/89 C. Victor C. Martinez I I TRIAD FOUNDATION ENGINEERING, Inc. Consulting Geologists Soils Engineering 94 DW0! -- I -L-T- 9c-ale/ By: TEST PIT LOG Project 221015 Rim Fire -Diamond Bar 'Teat Pit No.2 Location see geologic ma Jcb 1o. 88--494 Drill mate 6-13-89 Logged By JLK Driving Weight IT (FILL, NATURAL, BMROCK, etc.) : 4 MATERIAL (SAND, SILT, CLAY. etc.) - r1W as Description (color, moisture, density, etc.) W0 4J z 40 ca c w 13 0 ATTITUDE IMASUREMENTS: S - Bedding F - Fault 0 U ca 320 J - Joint C - Contact 0 TOPSOIL: Clayey SILT with Sand - dark -brown, moist ML very firm, moderately parous BEDROCK: SANDSTONE - Fine to Coarse Grained, light gray with orange -brown clasts, dense, moderately weathered & friable C N75E 20NW -- irregular contact - indistinct SANDSTONE - Fine grained, light gray, dense, well cemented - difficult to excavate Rock is moderately to thickly bedded with no distinct bedding plane surfaces i 1185E 62SE 9 END OF TEST PIT 8.5 FEET WaterNoGround or Caving u 1 FOUNDATIOIN ENGINEERING, Inc. PLAT B--2 TEST PIT LOD Project 22105 Rim Fire -Diamond Bar Test Pit No. 3 Location see geologic map Jab No. 88-494 Drill Date 6-13-89 Logged By JLK Driving Weight --- UNIT (FILL, NATURAL, BEDROCK, etc.); 0 MATERIAL (SAND, SILT, CLAY. etc.) Description (color, moisture, density, etc.) ATTITUDE MEASUREMENTS: B - Bedding F - Fault o 28" J - Joint C - Contact c 0 4 OM 80 W C U CA W U 0 TOPSOIL: Clayey SILT with Sand - dark -brown, ML slightly moist, very firm, trace to slightly porous 2 — More Sand, brown BEDROCK: Interbedded SILTSTONE & Fine Grained SA-NDSTONE - gray & brown, dense, moderately fractured 3 — weathered B NIOE 18NW - on irregular surface 5 Shear N20W 57SW Slightly weathered, difficult to excavate Little or no fracturing 7 - 8 END OF TEST PIT 6.5 FEET9 10 - No Ground Water or Caving TRIAD FOUNDAMON ENGINEERING. Inc. P LATE B-3 TEST PIT LOG Project 12105 Rim Fire -Diamond Bar Test Pit No. 4 Location see geologic map Job No. 88--494 Drill late 6-13--89 Logged By JLK Driving Weight --- IT (FILL, NATURAL, BEDROCK, etc.)- 4( S MLT, Y, etc.) c "0 0 *' V Descriptionrticn (t3l¢Jr, moisture, density, etc.)ci d ww 4 WUas Z 44 ATTITUDE MEASUREMENTS: rn W R - Bedding P - Fault 0 Z) U Cz 260 J - Joint C - Contact acct TOPSOIL: Sandy SILT with Clay - dark --brown,. ML, slightly moist, very Firm, trace to slightly orous BEDROCK: SANDSTONE - Fine to Coarse Grained light gray with orange concretions, dense, moderately weathered & friable A & Lone of it'" i SiTtstone is B N60E 21NW _._.. Fine Grained. SANDSTONE - slightly weathered, well cemented, difficult to excavate END OF TEST PIT 6.5 FEET No Ground Water or Caving win . 12- 114 TRIAD I 'I DATI II EINIGINEERING,, Inc. PLATE B-4 job03Jtll. 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