4027 4TH ST SE 2018-01-01 MF Import

January 14, 2003 HWA Proiect No.2002.146-21 practical, fixed leads should be utilized to reduce the potential for the pile being driven out of alignmrnt. We recommend a total of 8 test piles be driven initially, to detertnine the field conditions in conjunction with the conVactor's pile driving equipment. Test piles should be distributed across the building with at least one at each comer and in the middle. The test piles should be located such that they may also serve as production piles. No less than 24 hours after initial driving, the test piles should be re-struck. Ultimate capacities of these piles should then be evaluated using penetration resistance duting re-striking. We recommend use of the dynamic pile driving analyzer (PDA) on the test piles to monitor their dynamic behavior during initial driving and re-striking. The design recommendation may be revised if necessary based on resul!s of the PDA evaluation. In addition, the PDA data can be utilized to determine appropriate pile driving critecia for end of initial driving (EOID) conditions, thus reducing the number of piles requiring re-striking. Following completion of the test pile program, the geotechnical engineer should provide final driving resistance field criteria, using an appropriate dynamic pile driving analysis. Typically, penetration resistance at the end of initial driving is lower than during re- sttiking. However, it is not practical to re-strike every new pile after installatiun to estimate ultimate capacity. In our opinion, a minimum penetration resistance should be established for the EOID condition during produccion pile driving, based on the results of Ihe PDA data from the test pile program. In addition, a minimum of 10 percent of the production piles should be re-st:vck. The geotechnical engineer should select piles designated for re-striking, and the re-strikes should be performed at least 24 hours after driving. 4.4 SETTLE11fENT 4.4.1 General There aze several settlement issues at this site caused by rivo different compressible layers and a variety of loading conditions. Boring BH-1 indicates a compressible layer was encountered near the surface between depths of about 8 and 23 feet and a second compressible layer encountered between dep;hs of about 55 and 95 feet. From the site and exploration plan dated October 2002, the existing �ound surface elevation is about l2 feet along the southwest side of the building and about S feet neaz the south comer. The building finished floor elevation is 16.95. The building fnished floor is therefore about 5 to 9 feet above existing grade. There is a driveway and pazking area that surrounds most of the southwest and southeast sides of the building which appcars to be slightly below the building floor level at the building and at natural grade :002146 rqwn - final ]] 1{WA GEOSCIENCES INC. ��