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Home My WebLink AboutPermit Correspondence 2003-6-16 I ~~~ r : - ~) -~--- : -~- ~-I&::1"~ B~~-m12.._ElNAL-tNGIN~&- ~~-- - _-_ -' _'16U.Jse&U~l.~ -fDK Ovt~___CSWUC1JAWL __ ___ _ .-- -I M~\2Etl1~-, - -:- - --- --,-- -- - , ____ __~Ir * C'rtA?tO~CCilt<6_______ ____ Hn___ __ ___ -- ------ - -- -- -- ------ - ~ - - - --~----- ------ *" ,Jik..ft~_ cALL Wl1E~,-~()u- tfAVE_S-- M(~U I J?:S _ _ _ , _ ___Jb eo~Rt(v'--I\-!tSJS_,su_mt{wr_.EiS~_~wk. _ ____ ~~-I--J1/'S]) -ffi)MSE.. ,\,JJ~~N--J~\J~~]dL~b_WHt. BE _ ____,Jh~LE- ~__T CA:~ Rt~ tA~ _1+JE. _,__ , --Lt0~ -bLJfv1M*l(.- ~---- - ----- ~KSI - -..;f ;, ~A- ------- - -- '- -th~----- .-, ----- -~____ - ttMunJLI~-~_7ll__ __~_ ~~-lJ~ ___ ~ __ .. n Uun __~~___p&.3k~b.- S1'AfJ)N,b~-(K-6S , I - - ---- -- -- - - ----- ------- --- - -- ~ .1.' ( @ \ Branch Engineering I Inc. June 10, 2003 310 5th Street Springfield. Oregon 97477 (541) 746-0637 Fax (541) 746-0389 Mark and Suzanne Cushman PO Box 1514 Springfield, OR 97477 RE: Structural Observation at your residence - 739 South 68111 Street, Springfield, OR Branch Engineenng, Inc conducted several structural observatIOns at your reSIdence, culmmating rn a final observation on June 6. 2003. The purpose of these observations was to verify the installation 9f vanous structural elements as identified in the structural calculatIOns set by Branch Engineering, Inc, dated January 7, 2003. project number 02-129 The structural elements observed included revisions to the roof framing and installation of concrete foundation elements (see above referenced calculations set for specific requirements). This letter is to confirm that the required structural revisions had been executed for both the roof frammg and foundation elements. Specifically: 1 Roof framing revisions were observed to have been installed in accordance With the revised roof framrng plan prepared by Branch Engineering, Inc. and in conjunctIon With the above referenced structural calculations set 2 The beam identified for venficatIon In the floor plan revised by Branch Engineenng. Inc was observed to have been Installed, although the actual beam was a triple 2 x 12 3. The revised foundation el~ments, though not installed in accordance wIth the revIsed foundation plan prepared by Branch Engmeering, Inc are deemed to be acceptable substitutes The 24" square concrete footing specified by Branch Engineering, lnc was replaced with a contmuous footmg, similar to that shown on the foundatIOn plan (though not onginally mstalled) The 33" square concrete footing specIfied by Branch Engineering, Inc was replaced with an existing round concrete footing and a new concrete footing of sufficient size to whIch the deSIgn load will be dIstnbuted VIa an existing floor beam posted down to these two footings, Please note the our observatIons were conducted in accordance WIth the 1998 Oregon Structural Specialty Code section 220, and are not meant as a substitute for the required inspections Should you have any further questIOns regarding our observation for this project, please feel free to contact our office Smcerely, /~ .~- -- Rick Hernandez, P.E. CIVIL STRUCTURES TRANSPORTATION SURVEYING / ..SoIRE AssocIA" d INC- .. Geotechnical Engineering SolutIons Botre Associates Inc 520 NW 4th Street Corvall1s, Oregon 97330 TEL 541 753.53114 FAX 541,753,5347 May 12, 2003 Mark and Suzanne Cushman PO Box 1514 Springfield, Oregon 97477 Proiect 202.078 Subject: 739 South 68th Street Construction Report on Expansive Soil Mitigation Springfield, Oregon Dear Mr. and Mrs. Cushman: At your request, we have provided limited construction-observation services for the foundation Improvement work recently completed at your residence located at the above-referenced street address. Rlease consider this letter as a summary of our observations and documentation that the work was adequately completed. BACKGROUND The subject project consists of a single-family residence located at 739 South 68th Street in Springfield, Oregon, which has experienced limited foundation and wall cracking. BOlre Associates Inc. was retained in November 2002 to investigate the problem and determined the distress was caused by isolated soil swell. We recommended removing expansive soil from beneath portions of the foundation and replacing that material with a suitable engineered fill. A summary of our investigative work, findings and recommendations were provided in a letter- report dated November 25, 2002. CONSTRUCTION OBSERVATION Subsequent to our previous work, the home owners retained the services of a qualified contractor (Cascadia Enterprises) to complete the necessary house repairs. Boire Associates Inc. was contracted to ensure the portion of the improvements related to the expansive soil mitigation was adequately completed. The following is a record of our work. Site VisIt. Mav 1. 2003 We arrived at site and noted the contractor had made two trench excavations beneath the south wall footing. One excavation was located near the center of the wall and the other was located about 6 ft to the east. Both trenches were on the order of 6 ft in length. We observed the west trench excavation contained a significant amount of expansive sOil consisting of grey, moist, high plasticity, silty clay to clayey silt with a fissured and blocky structure. The excavation extended to a maximum depth of about 5 ft below grade (about 3% ft below the base of the footing) in order to remove the unsuitable material. The underlying soil was found to consist of grey-brown, iron-stained (mottled), moist, damp, low plasticity, slightly sandy silt with fragments of rock. The eastern trench was shallower (about 4 ft below grade) and encountered less expansive soil. A boulder was exposed on the west side of the trench that we determined could be left in place under the footing. Both trench excavations were relatively clean and we confirmed the contractor adequately removed all of the expansive soil from under the associated footing areas. We approved bot~ areas for subsequent backfilling with controlled density fill. Site Visit. Mav 5. 2003 We returned to the project site and observed the contractor had made two new trench excavations (between the other areas previously excavated and replaced) in order to remove the remainder of the problem soil from beneath the south footing line. The eastern trench extended to a depth of about 1 % ft below the footing and exposed a very limited about of potentially expansive soil followed by weathered rock. The western trench extended to about 2 ft below the footing level in order to completely remove the expansive soil at that location. We approved both excavations for backfill placement. Comments Based on the subsurface conditions exposed in the excavations beneath the footings, we determined the expansive soil area to be slightly deeper but also more confined (laterally) than originally estimated. The worst area of expansive soil was found to be located beneath the west side of the \Vest window on the south wall. At this location, the expansive soil extended to a depth of about 5 ft below grade (about 3% ft below the bottom of the footing). The bulk of the problem soil appeared to tapered-out within about 8 ft of the window to either side. We conducted an Atterberg limits test on a sample obtained from the worst area of expansive soil In order to classify the material and quantify the probable swell potential. Our testing Indicates the soil has a liquid limit (LL) of 85, a plastic limit (PL) of 40 and a plasticity index (PI) of 45. The results confirm the material is a very high plasticity silty clay to clayey silt (CH/MH) according to the USCS. A plot of the relative plasticity is shown on Figure 1. The natural water content of the soil sampled was tested at 49%, which maintained a "moist" and "stiff' consistency. Other pockets of "wet" and "soft" material were also discovered. These observations suggest extensive localized soil swelling had occurred and that further swelling might have been possible if the problem soil had not been removed. 739 South 68th Street Construction Report on Expansive Soli MItigation 2 May 12, 2003 PrOject 202.078 . , We have confirmed the limited foundation and wall cracking previously present on the south side of the subject residence was caused by swelling and heave expansIve soil. Through our construction observations, we have verified the problem soil has been adequately mitigated. The controlled density fill used as a replacement material should provide better foundation support than most native soil types. It has been a pleasure assisting you with this phase of the project. Please contact us if you have any questions. Sincerely, Soire Associates Inc. / 'EXPIRES' 12/31/.4'7 , 739 South 68th Street Construction Report on Expansive SOIl Mitigation 3 May 12, 2003 Project 202 078 4"' , A TTERBERG LIMITS PLASTICITY CHART 60 - CL-ML- II ~ ~ ~~e ()~ ' ~ ~. , ....,'" ~ l' I ,)( .1' \, /' 1- '\ ~ 1- - .;,- L , L --IlL I 7/ I-I- II I I ~! ( , /' Low plastic inorganic lmm ,.' Mediium . _I -7" "" cloys; sandy and- / - - plastic _, .-" slilt~ cl1ays 'I _ / - - inorganic,_" I" _/ cloys .,t~ I' i '" ,/ / J)" I I; " / --$~~~- -,,' ---- _ _ clayey silts .X,- " __ and sands ! ,I" _ CL I~" I I I . '/' OL I -1' ,YI orl_ /~r,~~~' _IML 1-1-' ,/ " II / I .,' I I I -L I 1111111 1-' '. Inorganic cloys of high plasticity .... ..... I ;~1 - /' ,"" ,.' "0 1- 50 L "",~e ~ ~ X 1l "C' C i?:' 30 i3 .;::; ,~ l1i a:: -- CH ,"" "" / ,,~ " \. , Sample $-1 1 I: . Micaceous or dial9maceous _ fine sandy and silty soils; elastic silts; organic silts, cloys, and silty cloys - ' , OH 40 20 o o 10 20 30 ! Inorganic and organ'ic silts ,and silty cloys of low plasticity; rock; flour; -I silty or clayey fine sands -I i I I i I I I I i I I 50 60 Liquid Limit (LL) or MH I I C I I 80 90 100 10 -, 40 70 A TTERBERG LIMITS TABULATED VALUES S-1 4 429 LL 85 Atterberg LimIts PL 'PI USCS 40 I 45 CH/MH Sample Depth (ft) Water Content ('Yo)