Response Amplification of Idealized Powerhouse Substructures to Earthquake Ground Motions

摘要

This report summarizes an investigation of the seismic response of Corps powerhouse structures. Research results include (1) the characterization and organization of the range in geometry of Corps powerhouse substructures for generator bays and service/erection bays; (2) development of representative, idealized substructure geometries for these types of structures; (3) construction of a series of finite element models of the substructures and subjecting these substructures to earthquake acceleration time-histories representing central/eastern United States ground motions and ground motions of the Pacific Northwest of the United States; (4) development of a database of first-mode periods of the typical powerhouse substructures; (5) computation of top-of-substructure acceleration time-histories and conversion of these time- histories into response spectra; (6) development of amplification factor curves (as a function of frequency) that quantify the magnitude of the amplification of ground shaking by the substructures; (7) development of a methodology for performing a simplified seismic analysis of the superstructure (or of the equipment on top of the substructure) that takes into account, in an approximate sense, the effect of the substructure on the response of the superstructures in the decoupled seismic structural analysis.