Laserfiche WebLink
1 <br /> I <br /> Geotechnical Engineering Report <br /> Proposcd Ncw Storm Watcr Vault <br /> Northwest Mitsubishi <br /> Novcmber 18, 2002 <br /> CG File No. 1397 � <br /> Page 5 � <br /> Fill tha[ will support settlement sensitive fcaWres, such at the planned retaining wall near the west � <br /> property line, should be compacted to 95 percent. IC th� volume of material to support thc <br /> structurc is relativcly minor, this may most easily be accomplished in the wet season by using <br /> crushed rock material. Some overc�:avation of existing fill may be needed at this retaining wall <br /> and this condiuon should be cvaluatcd during construction. <br /> Wc do not know thc cmbedmcnt depth of thc light pole columns at the west cnd of the cxisting <br /> parking lot. Excavation of the slope may undermme a portion of the soil supporting two of these <br /> poles. We re�ommend the contractor cvaluate this condit�ons before startin!;on the cxcavation. <br /> Structural Fill <br /> General: All fill placed beneath buildings, pavements or other settlement sensitive features, <br /> should be placed as structural fill. Structural till, by definition, is placcd in accordance with <br /> prescribed meihods and standards, and is monitored by an experienced geotechnical professional <br /> or soils �echnician. C•ield-monitoring proccdures would includc thc performance of a <br /> representati��e number of in-place density tests to document the auainmcnt of the desired d:gree <br /> of relativc compactian. <br /> Matcrials: lmportcd, all-wcathcr strucwral fill should contain no morc than 5 percent fincs (soil <br /> finer than a Standard U.S. Na 200 sieve),based on that kaction passing the U.S. 3/4-inch sieve. <br /> l�he planncd imported glacial till and the existing fill at the site may be difficult to work with <br /> outside of the dry summcrtime and difficult to compact due to high moisture content. We expect <br /> that it will be difficult to compact these materials to 90 percent �vith the planned construction <br /> sched��le. The cxisting fill with high organic content should be separated from the planned <br /> backfill soit and exportcd or used for landscaping material. <br /> Fill Placement: Following subgrade preparation, placement of the structural fill may proceed. <br /> Pill should bc placed in 8- to 10-inch-thick unifortn litis, and each lifi should be spread evenly <br /> and bc thoroughly compactcd prior to placement oCsubsequcnt lifts. All structural fill w�derlying <br /> building areas, and within a depth of 2 fect bclow pa�•ement and sidewalk subgrade, should be <br /> Cornerstone Geotechnical, Inc. �� <br /> / <br />