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Specifications 1 /M 2019- X I V,' Earth 1508 Broadway Street • Vancouver • WA 98663 Engineers, Inc. Phone: 360-567-1806 • Fax: 360-253-8624 www.earth-engineers.com RECEIVED January 16, 2015 FEB 12 2015 CITY OFTIGARD TimberRidge Development BUILDING DIVISION 1001 Northwest Lovejoy Street, #812 Portland, Oregon 97209 Phone: (503) 803-9184 Attention: John Duncan Email: johnduncan(ctrdcustomhomes.com Subject: Assumption of Geotechnical Engineer of Record & Geotechnical Investigation Report Review Proposed Single Family Residence 12412 Southwest Autumnview Street Tigard, Oregon EEI Report No. 15-004-1 Dear Mr. Duncan: The purpose of this letter report is to confirm that Earth Engineers, Inc. (EEI) is to accept the role as the Geotechnical Engineer of Record (GER) for the project referenced above. Our scope of services included reviewing the initial Geotechnical Investigation Report completed by Geotechnical Resources, Inc. (GRI), conducting 1 site visit to view the foundation subgrade soils, and reviewing the construction drawing set provided to us to confirm conformance with our geotechnical recommendations. Our services are being provided in accordance with EEI Proposal No. 15-P004, dated January 9, 2015, which you signed on January 11, 2015. CHANGE OF GEOTECHNICAL ENGINEER OF RECORD EEI has been hired to serve as the GER for this project. You have provided us with a Geotechnical Investigation Report by GRI for Mountain View Estates dated November 30, 2004 (GRI report #4134 GEOTECHNICAL RPT) for reference to subsurface soil conditions and geotechnical factors associated with the initial development of the subdivision. Summary of GRI's Past Geotechnical Investigation Report The referenced report by GRI was for the development and the geotechnical design criteria for the entire 22-Lot Mountain View Estates subdivision. At the time of their report, the proposed Mountain View Estates was on an undeveloped parcel(s) of land about 7-acres in size, and would consist of new roadways and single family lots. Four lots were located in Phase 2 (the south portion) and 15 lots were located in Phase 1 (the north portion) of the development. The lot EEI is addressing is Lot 9 within Phase 1. A EEI Report No. 15-004-2 January 20, 2015 Page 2 of 2 Emmons continued excavating for the east wall footing. EEI rep requested to be contacted once the excavation for the footings are complete and footing locations have been accurately identified so that we may evaluate the foundation bearing surfaces and the laterally supporting surrounding soils. EEI rep left about 10:40am 1111111 tit rig •i •441, 411111.10rirk L - " ;;%). 1111111 • 'N111111141114, PHOTO 1: Emmons General Contracting excavating at the northeast corner of the home Report Distribution (e-mail only): John Duncan, TimberRidge Development, (johnduncan @trdcustomhomes.com) Field Staff Name(Print) Jeremy Fissel, PE Report Reviewed By Troy Hull, PE, GE Field Staff Signature ' n Copy of Handwritten Report Left on Site No Our inspection does not relieve the contractor from performing in accordance with their contract and approved permit documents. A 7 40 Earth 1508 Broadway Street Vancouver, Washington 98663 Engineers, Phone (360) 567-1806 (n` Fax (360) 253-8624 DAILY FIELD OBSERVATION REPORT Page 1 of 2 Client: TimberRidge Development Permit No City of Tigard #MST2014-00196 Date: January 20, 2015 Project: New Single Family Residence Address: 12412 SW Autumnview Drive Report No 15-004-2 Tigard, Oregon General Contractor. Subcontractor Emmons General Weather: partly cloudy, 40'S TimberRidge Development Contracting Location or Items Inspected: Foundation subgrade evaluation • New Inspection Re-Inspection Type of Observations At Completion • In Progress Post Completion Continuous • Periodic Other Detailed Observation Notes As requested by John Duncan with TimberRidge Development, EEI representative Jeremy Fissel, PE was on site at about 9:50am to observe soils excavated for the construction of the foundations for the referenced home in accordance with EEI Report No. 15-004-1. On arrival, Shawn with Emmons General Contracting (earthworker for project) was excavating the north portion of the east continuous foundation of the new home. John Duncan with TimberRidge Development was also on site today. EEI rep observed that the excavation of the east wall will be a stepped-footing. A stepped-footing detail is not provided in project drawings. EEI rep observed that the excavation cut at the northeast corner of the home was vertical and about 5'% feet in height. EEI rep recommended that the excavations be cut to no more than 4 vertical feet, and if taller excavations are needed, that those soils above 4 feet be excavated at a 1H:1V behind the excavation face. The excavator cut the excavator at the northeast corner of the home accordingly. The soils excavated to near subgrade elevation was at the northeast corner were fill soils comprised of gravelly silt with sand and trace cobbles in a moist condition. Some gravel was up to 3 inches in particle size. Cobbles were generally less than 6 inches in particle size. The subgrade was evaluated using a '/2-inch diameter steel soil probe under moderate pressure. This generally resulted'in less than 1 inch penetration; the tip of the soil probe generally hit gravel-sized subsurface particles. Based on the GRI report dated November 30, 2004 for the subdivision, and our observations, the subgrade soils excavated at the north portion of the east foundation wall were suitable to support a bearing pressure of 1,500 psf as shown in project plans. EEI rep reminded Mr. Duncan and Sean with Emmons than the soils from the original fill embankment need to extend no lower than a 1H:1V line extending from the bottom of the footings to allow for passive pressure resistance. Because the site is sloped and the foundation plan shows several spread footings in the central portion of the home, excavation for the east wall footing should be kept minimal to maintain our recommended soils coverage for those footings located uphill (west). In addition, the bottom of the footing should be located at least 10 lateral feet from the surrounding original (prior to lot excavation) slope. EEI Report No. 15-004-1 January 16, 2015 Page 2 of 5 GRI's subsurface investigation consisted of 9 test pits excavated up to 121/2 feet and 3 soil borings advanced to depths up to 30 feet below the surface. Boring B-2 was located in Southwest Autumnview Street, near the northwest corner of Lot 9. In general, GRI's subsurface investigation resulted in 3 soil types encountered in Boring B-2: (1) Gravel Fill, (2) Silt, and (3) Basalt. In B-2, the gravel fill was about 8 feet thick and underlain by stiff silt to a depth of 17 feet. Very soft to soft basalt was encountered in B-2 from 17 to their termination depth of 30 feet below the surface. GRI concluded in their Investigation Report that the site was suitable for the proposed development. Geotechnical considerations associated with the proposed development were moisture-sensitive fine-grained soils, presence of seeps and springs, and shallow depth to basalt bedrock. GRI provided design recommendations for allowable shallow foundation bearing capacity, recommendations for embedded retaining walls, and estimates of shallow foundation settlement. EEl's assumption of Geotechnical Engineer of Record Based on our review, we concur with the geotechnical recommendations provided in GRI's Investigation Report dated November 30, 2004 for Mountain View Estates and agree to assume the role of Geotechnical Engineer of Record. CURRENT SUBDIVISION DEVELOPMENT Since the issuance of GRI's Investigation Report and the time of our requested service for the new single family residence at 12412 Southwest Autumnview Street (Historical Lot 9), all homes (with the exception of Historical Lot 9) have been constructed within Phase 1 of the subdivision as shown in GRI's report. It does not appear that Phase 2 of the GRI project has started construction yet. SITE VISIT On January 12, 2015 Mr. Jeremy Fissel, PE of EEI was requested to visit the site during the initial stages of excavation to evaluate potential subgrade conditions. On arrival, the majority of the excavation completed so far was at the planned garage area at the north portion of the property off of Southwest Autumnview Street. About 4 feet had been excavated to near design subgrade elevation. Subgrade soils were fill materials comprised of gravelly silt with sand. Some cobbles (up to about 8 inches in diameter) were observed in the excavation sidewall excavation of the lower level. Based on GRI's Investigation Report as well as EEI representative's observations, the soils at the garage subgrade are similar to GRI's findings and are in our professional opinion are suitable to support 1,500 psf bearing capacity. See Photo 1 below. EEI Report No. 15-004-1 January 16, 2015 Page 3 of 5 ,;;..4_. �' � .,. -� ,,, a _ 'r::i"' ,t ,�x •',,''" ''''*:.'V'-' > '1:. ',,_,Y: '''.';*41v, :..--,,,.- ,, - ,ate+ ,a!0c-f'" Ar r ) yy i ;../r - i-�T f� l 'Ri T '� 4 w F•rMa .Y� *.. a r„....—„-., ..'* ._., „Lk., �, F PHOTO 1: Excavation for garage entrance at north side of home Another area had been excavated near the southwest portion of the planned building. It was understood that this area was exposed to have EEI evaluate these particular soil conditions. The exposed soils were stiff, brown and grey silt in a moist condition. EEI representative used a 1/2-inch diameter, pointed steel soil probe under moderate pressure to evaluate this subgrade. This resulted in about 1/2-inch penetration indicating stiff conditions. Based on EEI rep's observations, this soil was suitable to support 1,500 psf bearing capacity as recommended in GRI's report. See Photo 2 below. EEI Report No. 15-004-1 January 16, 2015 Page 4 of 5 i • is • . . ..‘, 4•0 • • . . PHOTO 2: Brown and gray stiff silt found near the SW corner of the planned residence PLANS REVIEW John Duncan, Senior was onsite performing the preliminary excavations. He provided Mr. Fissel with a set of project plans that included architectural drawings by RAE Design Associates and structural drawings and details by Sherman Engineering, Inc. (SEI). These drawings were stamped by the City of Tigard showing "Reviewed for Code Compliance for Permit No. MST2014-00196, dated 11/17/2014." This drawing set included 10 sheets by RAE (Sheet 1 through 10, all dated 9/15/2014) and 6 sheets by SEI (S1 through S6, all dated 8/1/2014). The foundation plan for the home, Sheet 7 by RAE shows continuous footing and spread footings are used to support the new home. The General Notes on Sheet 10 by RAE shows a maximum allowable soil bearing pressure of 1,500 psf. EEI Report No. 15-004-1 January 16, 2015 Page 5 of 5 In addition, the General Notes by RAE cites "do not excavate closer than 11/2 : 2 below footings". EEI representative recommended on site that temporary excavations should not be closer than 1 H:1 V below footings and that all permanent slopes be 2H:1V or shallower. Mr. Fissel recommends that EEI have the opportunity to observe the subgrade for all soil bearing surfaces once they become excavated. Mr. Duncan said that EEI will be requested to return to the site once the footings have been excavated. Mr. Duncan provided Mr. Fissel with the referenced set of drawings for additional review. UPCOMING SCHEDULE As EEI representative recommended on site, we want to review the footing subgrade conditions once excavated. EEI is available for the foundation inspections as needed on a time and materials basis in accordance with the rates in our proposal No. 14-P004 dated January 9, 2015. LIMITATIONS The geotechnical recommendations and assumption of the GER for 12412 Southwest Autumnview Street presented in this report are based on the available project information described in this report. If any of the noted information is incorrect, please inform EEI in writing so that we may amend the recommendations presented in this report if appropriate and if desired by the client. EEI will not be responsible for the implementation of its recommendations when it is not notified of changes in the project. This report has been prepared for the exclusive use of TimberRidge Development for the specific application for the new single family residence at 12412 Southwest Autumnview Street. EEI does not authorize the use of the advice herein nor the reliance upon the report by third parties without prior written authorization by EEI. We appreciate the opportunity to perform this geotechnical engineering evaluation. If you have any questions pertaining to this report, or if we may be of further service, please contact Jeremy Fissel at 360-567-1806 (office) or 503-701-8879 (cell). Sincerely, �,01) pNFpf`SS� Reviewed b Earth Engineers, Inc. ��� N Fq 2 by: 88288PE • OREGON 418ER „qv c-,yy M fvv Jeremy Fissel, P.E. Troy Hull, P.E., G.E. Geotechnical Engineer RENEWAL DATE:, r 2/51 ,"' Principal Geotechnical Engineer R • VISION CLEARANCE S W A U TUMN VIEW STREET EASEMENT c .r\ d% S 8949'32" E 64.91' i s .>10 b — I — — �/ —8'-PUBLIC -- — a d�� \--V° /o UTILITY EASEMENT p- \..-O / o N / £'£' r r *t� N N co / a f'` 1. 18,00 .0 W o/ Clt Z ° °o z ? 10.4 ry 0 cs +-- - 21 l� �� lit h Z a �; L Q ti ti Z Z 3 �!-,J 3 Q y op Q 5.0 N1 LuW ap 0 te .§.itt 11.50' o 17.50' 20 v^^J c- - OT w 20.50" 9 O° 3 7d 0 •_ (/) lo 9CM X39 0 (4 < N LOX X38 _in J a> 2 010 I c I NI e h I °: II I cs sNi SIGNED ON: 1 I No / s REGISTERED -6\i° `c) N 8949'32" W 6706' 0)0 8(f) PROFESSIONAL cb LAND SURVEYOR Ods a 2007 JAMES BURTON BROWN 60379 VALID THROUGH DECEMBER 31, 2015 CLIENT: TIMBER RIDGE STAKEOUT Ag ORIG. DATE: 12116/2014 LOT 15, MOUNTAIN VIEW ESTATES CENTERLINE CONCEPTS DRAWN BY: CJB LAND SURVEYING, INC. CITY OF TIGARD,WASHINGTON COUNTY, OREGON 729 MOLALLA AVE., SUITE 1 & 2 SHEET No. 1 OF 1 OREGON CITY. OREGON 97045 SCALE: 1"=20' PHONE 503.650.0188 FAX 503.650.0189 Plotted: 1/21/2015 - 7:13am, 41:\BUILDER SERI?CES\Stakeout Drowing\LOT 15, MOUN71AN NEW ESTATES\dwg\STAKEOUTdwg, Layout: Layout?