Guidelines for the seismic evaluation of existing buildings

Because of the difficulties in applying current earthquake requirements in the National Building Code of Canada to existing buildings, a document "Guidelines for the seismic evaluation of existing buildings" has been developed to provide alternative criteria. The Guidelines are based primarily on similar U.S. documents with changes to suit Canadian seismicity and practice. The basis of the document is earthquake damage experience as it relates to life safety, and the methodology is based on the identification of deficiencies of the building from a master list known from earthquake experience to result in life-threatening failures. Potential deficiencies are checked against evaluation criteria which are based on the NBC/CSA seismic limit states design using a load reduction factor of 0.6. The paper provides a background on those features which differ substantially from the NBC requirements.