On calculating equivalent static seismic forces in the 2005 National Building Code of Canada

Several major changes were introduced in the seismic design provisions of the 2005 edition of the National Building Code of Canada (NBCC). The lateral earthquake design force at the base and the lateral force distribution along the building height depend on the design spectra and on modification factors that, in most cases, require a large number of interpolations and calculations. This note presents a spreadsheet that facilitates determination of the 2005 NBCC seismic design forces from the equivalent static force procedure.