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Home My WebLink AboutPreliminary Soils and Foundation Investigation - COM Engineering / Geo-Tech Reports - 3/13/1972 O-r=02_,-&I3S -W:A.S1-1IW0-T0N, !Mo. / a Serendipity.Inc.subsidiary F'ounclation anti Soils Engineering, C+ eology 12893 N.E. 15th Pl. Bellevue, Washington 98005 (206) GL 5-2018 502 So. 11th St. Tacoma, Washington 98402 (206) BR 2-4347 March 13, 1972 W-814-30 Seifert, Forbes and Berry 925 Tacoma Avenue South Tacoma, Washington 98402 Attention: Mr. Dean Haas Re: Preliminary Soils and Foundation Investigation Puget Sound National Bank Site Belfair, Washington Gentlemen: In accordance with your request, we have completed a preliminary soils investigation on the subject site. This report summarizes our work-_ . and contains preliminary conclusions and recommendations pertinent tq- e`' design of the project. �' � SITE DESCRIPTION The proposed site is located on the southwest corner of the inter- section of State Highway No. 3 and Belfair Street in the city of Belfair, Washington. The northeast part of the parcel is presently occupied by an old building with paved parking from the building out to both Belfair Street and the State Highway. The building and the paved parking occupy nearly half of the parcel. The site is fairly level in the north half, but slopes gently west and south in the south portion. The site is covered with grass with the exception of some gravel driveways at the west and south sides of the existing building. The property drains toward the southwest corner. EXPLORATION PROGRAM A total of six (6) test pits were excavated on the site utilizinci a tractor mounted backhoe. Their depths varied from four to eleven feet.,�,, ;._, All materials encountered were logged by an engineering geologist from 'S: VAN Nuys,CALIF.• SANTA ANA,CALIF.• PALO ALTO.CALIF.0 LAS VEOAS.NEV.0 BELLEVUE.WASH. TACOMA•WASH. 0 HONOLULU.HAW. •MURRAY HILL.N.J. a • i W-814-30 Seifert, Forbes and Berry Page Two March 13, 1972 Approximate test our office. Logs of the pits are presented in Tabdloef this report. pit locations are shown on the site plan at the ez x loration was not accomplished in the northeast part o the locations site E p paved parking. In addition., because of the existing building and of utilities were not known in this area. 1 SUBSURFACE CONDITIONS The materials encountered were loose to medium dense, brown, fine to medium grained SAND with a few six to twelve inch thick beds of brown, silty, fine SAND and brown, medium �Ihowever,hlthis lens may be any sandy GRAVEL was found in Test Pits old drainfield. In the south part of the site, one to two feet of fill composed of n placed over the original topsoil. (See fine SAND and silty SAND has bee Site Plan.) $ n Test Pits 1 and 5, a normal sequence of soils was encountered. I its appeared (See logs in Table A.) Generally, the materials in these two p to be somewhat denser than in the other pits e silt beds . In addition, there is a thicker ! section of sand immediately beneath the topsoil and overlying th than that observed in other pits. elow the surface Groundwater seepage was noted at six to nine e feeeet bbelowthe surface i in Test Pits 1 and 5, and from three and a half to fiv 4 and 6. The difference in these groundwater elevations is in Test Pits 2, the north t probably from the difference in surface elevation at the site; i. e. , portion is higher than the south portion. DESIGN CONSIDERATIONS 1. Traffic in and around the existing building probably has densified the underlying soils to soiree extent. It is strongly recommended that after removal of the existing building and paved parking, test pits be dug in thi s area to determine the underlying soil conditions. Final siting of the new building should be delayed until this information is I available. 2. All existing fill, topsoil, and buried facilities, ilitie , such The void septic and fuel tanks should be removed prior to construction. should be filled with compacted sand and gravel. G- IMO E3, IMZC• W-814-30 Seifert, Forbes and Berry Page Three March 13, 1972 3. After completion of stripping, the original soil should be thoroughly compacted using a vibratory steel roller. After the proof-rolling procedure, the site should be raised 4° to the desired grade with a compacted, granular fill. The placement of to the fill should be supervised and the material shoulde ASTM b Dc mpa or Led at modi- least 90% of the laboratory maximum density fi ed AASHO T-180). If it becomes necessary to place uch as sandill during y gravel months, the fill materials a madteria; by we be limited ight,ypassing the No. 200 sieve. with no more than 5% o . 5. Footings should be at least twelve inches wide and should be founded at least eighteen inches below a acent l l should be provided under If possible,. a two-foot thiround and slab surfaces. ck mat of compatd f all footings and the slab. for spread i g. Tentative maximum allowable bearing pressures for per footings on at least t<vo feet of camp Se tlefinent°es amate be s0 cannot be made square foot (dead load + live lod ) until the building has been sited and structural configurations determined. The recommendations herein are subject to n difie Ligation subse- by the final location of the building and additional subsurface quent to site clearing. se concerning this stage of the project, If any further questions ari please do not hesitate to call. Respectfully submitted, GEOLABS-WASHINGTON I INC. L4eS:ton�, Engineering Geologist Vas�riy lvin R. Zeman, P. E. , LS/mh o `� FSS�ONAL b�.e. C� � ULASF'J. INd. f TABLE A TEST PIT LOGS i Depth - ft. Soil Classification Test Pit No. 1 ; 0. 0 - 1. 0 Loose, brown, silty, organic SAND. (Topsoil) 1.0 - 7. 0 Loose -to medium dense, brown to grey, fine to medium, clean SAND. 7.0 - 8. 0 Soft to medium stiff, brown, thin-bedded, moist, sandy SILT. 8.0 - 11. 0 Medium dense, brown, clean, fine to medium SAND. (Seeps from 7 to 9 feet.) Test Pit No. 2 i 0. 0 - 2. 0 Loose , brown, silty, fine to medium SAND with occasional irregular masses of black to brown, organic topsoil. (Fill) 2. 0 - 3. 0 Loose, reddish brown, organic, silty SAND. (Topsoil) 3.0 - 7. 0 Loose to medium dense, brown, clean to slightly silty, fine to medium SAND. 7.0 - 8.0 Soft to medium stiff, brown, wet, sandy SILT. (Seeps from 4 to 8 feet.) (Hole caving from 4 to 8 feet.) (Depth to water after 30 minutes = 3. 5 feet.) Test Pit No. 3 0. 0 - 1. 5 Loose, brown, fine SAND. (Fill) =f 1. 5 - 3.0 Loose, reddish brown, silty, fine SAND. (Topsoil) 3.0 - 4. 0 Medium dense, brown, clean, sandy GRAVEL. (Drainfield?) Test Pit No. 4 0. 0 - 2.0 Loose, brown, fine to medium SAND. (Fill) 3f = 2.0 - 3. 5 Loose, reddish brown, silty, fine SAND. (Topsoil) 4 37 3. 5 - 4.5 Medium dense, reddish brown, wet, clean, sandy GRAVEL. i 4.5 - 6. 5 Medium dense, brown, silty, fine to medium SAND. c1xn0'=...aW313. xsvC. W-814-30, . 4 i TEST PIT LOGS (CONT.) Depth - ft. Soil Classification Test Pit No. 4 (cont.) 6.5 - 8. 5 Loose to medium dense, grey, clean to slightly silty, fine to medium SAND. (Seeps from 4 feet to bottom.) (titer 30 minutes caving j4 feet to bottom.) (Water table 3. 5 feet of Test Pit No. 5 { 0.0 - 1. 0 Loose, reddish brown, silty SAND. (Topsoil) lean, fine to 1.0 - 6.0 Loose to medium dense, bro o grey, medium SAND. 6.0 - 7. 0 Soft to medium stiff, brown, thin-bedded, sandy SILT. 7.0 - 10. 0 Loose to medium dense, brown, interbedded, clean, fin ! SAND and silty, fine SAND. (Numerous seeps from 6 feet to bottom.) (Hole caving from 3 feet to bottom.) (Sand to i 6 feet stands fairly well except where undermined by caving.) Test Pit No. 6 € 0.0 - 1. 5 Loose, brown, silty, fine to medium SAND. (Fill) 1.5 - 2. 5 Loose, reddish brown, moist, silty, fine SAND. (Topsoil) 2. 5 - 5.0 Medium dense, brown, moist, fine to medium SAND with thin beds of silty, fine SAND. 0 Soft tan moist SILT. 6.0 - 10. 5 Loose to medium dense, tan and brown, interbedded, fine, i t clean SAND and silty, fine SAND. (Seeps at 5 feet.) (Caving from 5 feet to bottom. ) C;- n 0 L.,A. %3. I N C.