Stiffness and Damping Properties of a Low Aspect Ratio Shear Wall Building Based on Recorded Earthquake Responses

An investigation into the structural properties and seismic responses of a low aspect ratio shear wall building, which has construction similarity to typical nuclear plant structures, has been performed using actual recorded earthquake motions. This effort used a combination of modal identification to obtain structure modal parameters directly from the recorded motions, and elastic structural analysis using methods and criteria frequently employed by the nuclear industry. Modal parameters determined by modal identification provide excellent fits to the building motions recorded during the 1984 Morgan Hill earthquake. Modal parameters identified for the 1989 Lorna Prieta earthquake are more uncertain. Investigation of building stiffnesses generally confirms the adequacy of bounding estimates currently recommended for nuclear plant structure seismic analysis. Damping values identified for this building supplement the database being compiled to investigate current nuclear plant structure damping criteria.