PDF - Centralia College

• The lateral system for the south cafeteria/lounge wing for seismic loads in the east west directionconsists of a solid shearwall on the south elevation and the interior walls dividing this wing with theolder library portion of the building. The diaphragm, which consists of diagonal 1x sheathing, isoverstressed in distributing the loads to these walls. It is unknown whether plywood sheathing hasbeen added to the diagonal sheathing, as is sometimes done as part of re-roofing.• The lateral system for the roof diaphragm of the old library consists of shearwall elements on thesouth, east, and west elevations, forming a three sided box. However, the diaphragm consists ofdiagonal 1x sheathing, which is overstressed in this condition. The drift of the roof framing duringthe 2001 Nisqually event was caused by this deficiency in the diaphragm. This building drift is ofconcern due to the amount of eccentricity left in the beam to column connections. This eccentricitycan cause the columns to fail under the dead load of the roof framing.• The second level of the old library consists of a rigid, concrete diaphragm. The cmu walls along thesouth end of the library, and the cmu walls in the stair core provide lateral resistance to for seismicloads. However, the location of these elements provide a center of rigidity that does not match thecenter of mass, leaving the diaphragm torsionally irregualar.• From our conversation with the Maintenance Personnel, we understand that there have been severalroof leaks, with water penetrating into the building. No wood deterioration is visible from theinterior, but some areas of water damage can be seen.The Student Center does not meet with the basic Life Safety objectives for buildings during a seismic event.This building also possesses a high probability of sustaining structural damage during a code level seismicevent and presents a risk to the building occupants. Further analysis of this building will be necessary todetermine a mitigation plan for the repair of the structural deficiencies listed above.If you have any question concerning this study, or our conclusions, or if we can be of any further assistance atthis time, please feel free to contact me at (253) 284-9470.Sincerely,SWENSON SAY FAGÉTA Structural Engineering CorporationRyan H. Reichman, PEPrincipal