Engineering applications of new probabilistic seismic ground- motion maps of Canada.

New peak horizontal acceleration and velocity zoning maps with a probability of exceedance of 10% in 50 yr and 7 seismic zones are developed from new probabilistic strong seismic ground-motion estimates for replacement of the 1970 seismic zoning map in the National Building Code of Canada. The adoption of a probability of exceedance of 10% in 50 yr produces reference seismic ground motion appropriate to the level of protection afforded by provisions of the current code; the use of two ground-motion parameters, the relative levels of which vary considerably throughout the country, provides independent reference levels for structures having short and long fundamental periods. For calculating seismic base shear, a new seismic response factor is derived. These and associated changes in seismic design provisions have been recommended for adoption in the 1985 edition of the National Building Code of Canada.-from Authors