Civil Engineering Association

PERFORMANCE-BASED SEISMIC VULNERABILITY EVALUATION OF EXISTING BUILDINGS IN OLD SECTORS OF QUEBEC

To perform a seismic vulnerability evaluation for the existing buildings in old sectors of
Quebec, two major tools at two different levels are missing: first, in the context of the
seismic vulnerability assessment of a group of buildings, an updated rapid visual screening
method which complies with the Uniform Hazard Spectra presented in the 2005 version of the National Building Code of Canada (NBCC) does not exist; and second, in the context of loss estimation studies, capacity and fragility curves which are developed based on the specific building typologies present in those sectors are required. In this research work, in the first place, a building classification for the existing buildings in old sectors of Quebec considering the masonry as the main construction material is proposed. Later, an updated rapid visual screening method—in the form of vulnerability indices for different typologies and cities in Quebec—which is adapted to the Uniform Hazard Spectra in NBCC 2005 is proposed. The structural vulnerability indices (SVI) are calculated through the application of the improved nonlinear static analysis procedure in FEMA 440 Improvement of nonlinear static seismic analysis procedures for three levels of seismic hazard. A set of index modifiers are also presented for the building height, irregularities, and the design and construction year. To deal with the second problem, on the other hand, a performance-based seismic vulnerability evaluation method is applied to examine the structural performance of two buildings—a 6-storey industrial masonry building and a 5-storey concrete frame with masonry infill walls, as two of the building classes constructed vastly in old sectors in Quebec—at multiple seismic demand levels. The results of such an assessment are used to develop dynamic capacity and fragility curves for the target buildings. The Applied Element Method is used here as an alternative to FE-based methods to conduct a thorough 4-step performance-based seismic vulnerability evaluation. To this end, the Incremental DynamicAnalyses (IDA) for the buildings are carried out using various sets of synthetic and real ground motions representing three M and R categories. Consequently, the fragility curves are developed for the three structural performance levels—Immediate Occupancy, Life Safety, and Collapse Prevention. Finally, the mean annual frequencies of exceeding those performance levels are calculated by combining the data from the calculated fragility curves and those from the region’s hazard curves. The proposed method is shown to be useful to conduct seismic vulnerability evaluations in regions for which little observed damage data exists.