Limit states criteria for structural evaluation of existing buildings

Difficulties have been encountered in applying the requirements in the National Building Code (NBC) and referenced CSA standards to the structural evaluation and upgrading of existing buildings in Canada. The Associate Committee of the NBC has therefore initiated an effort to provide guidelines on the application of Part 4 of the NBC to existing buildings, allowing alternative requirements where needed. As an initial step towards fulfilling this goal, this paper reviews all aspects of limit states criteria for structural evaluation and proposes minimum load factors based on a life safety criterion. The proposed load factors allow more flexibility in practice but require more professional judgment. Key words: existing buildings, structural evaluation, criteria.