A rapid seismic screening procedure for existing bridges in Canada

The seismic behaviour of existing bridges in Canada remains an important problem, since most of these structures have been built before modern seismic provisions. Recent earthquakes around the world have demonstrated that such older structures can behave poorly under even a moderate ground excitation. The cost for a systematic evaluation and retrofit of bridges in Canada would be prohibitive and therefore such an operation is impractical. As an alternative, this paper presents a rapid seismic screening procedure for existing bridges in Canada. The main goal of the procedure is to allow owners to prioritize their structures for further detailed seismic evaluations. The procedure can also be used to provide data for a postearthquake inspection of bridges located in the epicentral region. Special care has been taken to make the method rapid and simple. Technical personnel without any specific knowledge of seismic design should correctly perform the screening evaluation. The procedure can also be easily incorporated in an existing bridge inspection program. The paper describes the various parameters of the screening procedure. Screening examples of bridges in the Montreal metropolitan area are also presented. Key words: bridges, earthquakes, evaluation, seismic screening.