Sélection, étalonnage et orientation critique des secousses sismiques bidirectionnelles pour l'analyse des bâtiments situés dans l'Est du Canada

The seismic analysis of multi-storey buildings is a crucial step in designing structures located in Eastern Canada. Indeed, this area of moderate seismicity combined with a high population density makes it one of the most at risk across Canada. In this context, the 2010 edition of the National Building Code prescribes different rules to adequately take into account seismic effects on structures. However, due to their random nature, earthquakes in Eastern Canada are usually randomly oriented (since it is impossible to determine directions for the active tectonic faults) and have seismic components in several directions. The NBCC 2010 uses an empirical combination rule to represent the bidirectional effects in the horizontal plane (the 100%-30% rule). Another factor to consider while conducting seismic analyses is the angle of application of the seismic loads to obtain a good approximation of the maximum internal forces induced in different structural elements. Several other methods have been proposed in the literature to replace the 100 % - 30 % method that is presently used in the NBCC 2010, which some claim is not adequate. The different methods depend in particular on the type of analysis performed. For spectral analysis, two techniques seem to emerge in the literature: the SRSS method (square root of the sum of squares) and CQC3 method, which uses the modal cross correlation coefficients obtained from analysis performed in two perpendicular directions.