1130 RAINIER AVE WHOLE SITE DOCUMENTS 2016-01-01 MF Import

�� Everelt Housing Authoriq� Nlay 16, 2012 � JN 12080 Page 4 bathing. Excessive �vater vapor trapped within structures can result in a variety of undesirable conditions, including, but not limited to, moisture problems tvith flooring systems, excessively moist air within occupied areas, and the growth o( molds, (ungi, cmd other biolcgical organisms lhat may be harmful to lhe health of the occupants. The designer or architect must consider the potential vapor sources and hkely occupant uses, and provide sufficient ventilation, either passive or mechaniczl, to prevent a build up of excessive water vaper within ihe planned structure. Geotzch Consultants, Inc. shouid be allc�ved to revie�v ihe final deveiopment plans to verify that the recommendalions presented in lhis report are adequalely 2ddressed in the design. Such a pian revie�,v �vould be additional vdork beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, developmerit, and geotechnical constrainls that become more evidenl during the review process. 4Ve recommend including this report, in its entirety, in lhe project contract documents. This report shou!d also be provided to any future property owners so they will be aware of ovr findings and recommendations. SEfSMIC CONSIDERATIONS In accordance �vith the Intemational Building Code IBC, the site soil profile within 100 feet of the ground suriace is best represented by Site Class Type D(Stiff Site Class). As noted in the USGS website, lhe mapped spectral acceleration valu� for a 0.2 second (Ss) and 1.0 second period (S,) equals 1.15g and 0.40g, respectively. The IBC states that a site-specific seismic study need not be performed provided that the peak ground acceleration be equal to So512.5, tivhere Sos Is determined in ASCE 7. It is noted that Sos is equal l0 213S,�.,S. S�,,S equals Fa times S5, where Fa is determined in Table 11.4-1. For our site, F� _ 1.04. Thus, the calculated peak ground acceleration that we utilized for the seismic-related parameters of this report equals 0.32g. The site soils are not susceptible to seismic liquefaction because of lheir dense nature andlor the absence of near-surface groundwater. CONVENTIONAL FOUNDAT/ONS As noled earlier, �vhere overexcavation depths are nol significant, the proposed structures can be supporled on conventional continuous and spread footings bearing on undisturbed, medium-dense native soil, or on structural fill placed above this competent native soil. See the section entiUed General Earthwork and Structural Fill for recommendations regarding ihe placement and compaction of struclural fill beneath structures. Adequato compaction of structurai fill should be verified with frequent density testing during fill placeirenl. Prior lo placing structural fill benealh foundations, the excavation should be observed by the geotechnical engineer to document that adequate bearing soils have been exposed. We recommend that continuous and individual spread footings nave minimum widlhs of 16 and 24 inches, respeclively. Exterior footings should also be bottomed at least 18 inches below the lowest adjacent finish ground surface for protection against frosl and erosion. The local building codes should be reviewed to determine if dif(erent footing evidths or embedment depths are required. Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending upon site and equipment constraints, this may require removing the disturbed soil by hand. GcOTECH CONSULTANTS,INC.