Rapid seismic vulnerability assessment of school buildings in Quebec

The seismic performance of schools deserves special attention because of their unique occupancy characteristics and important post-earthquake role. Past experience has shown that school buildings are especially vulnerable to earthquakes; they are often irregular structures, and most of them were designed and built prior to the introduction of modern building codes that adequately address earthquake-resistant design and seismic hazard. This research addresses the concerns related to school earthquake safety for the province of Québec by developing a seismic screening method for the evaluation of the public school buildings.;Rapid visual screening methods are intended to be coarse screening procedures requiring little resources and time per building. The adapted seismic screening method that was developed is a score assignment procedure, with the final score dependant on the seismicity, lateral load resisting system type, building height, construction year, potential structural deficiencies (horizontal and vertical irregularities, deterioration and short concrete columns), potential for pounding and local soil conditions. Scores are calculated based on the capacity spectrum method, a nonlinear static analysis procedure. The methodology is inspired by the Rapid Visual Screening of Buildings for Potential Seismic Hazard (FEMA154) procedure, which has been adapted and enhanced to serve as a screening tool for schools in Québec. It reflects these building’s specific characteristics and takes into consideration the province’s seismicity as stipulated in the 2010 edition of the National Building Code of Canada (NBC).;The method is grounded on the extensive characterization of 101 individual school buildings, pertaining to 16 different school sites. These schools are designated as post-critical shelters and a secondary objective was to assess whether they can achieve this function in case of a design-level earthquake. Schools were characterized by site visits, study of building plans, and consultation of the city’s microzonation map. Furthermore, an ambitious experimental program sought to determine the dynamic properties of all buildings and the characterization of the local soil conditions through ambient vibration measurements (AVM). Finally, a comprehensive inventory of unreinforced heavy masonry partition walls was made. From the collected information general characteristics of schools could be established, which were corroborated by an extensive literature review. AVM records on buildings permitted an assessment of some of the generic capacity curves used for the calculation of the scores by comparing their elastic range to the experimental fundamental frequencies. Local soil conditions determined from AVM where in good agreement with other sources of information. The experimental procedure was also found to be simple enough so its application is feasible in a rapid seismic screening context.;The application of the screening method to the sample of schools classified 18 buildings as having a very high, 18 a high, 44 a moderate and 21 a low priority for future intervention. This information, together with average scores per school site, determines which sites are more likely to be adequate as post-earthquake shelters. A more detailed analysis of the results and comparison with two relevant existing rapid seismic screening methods (FEMA154 and the Manual for Screening of Buildings for Seismic Investigation, NRC92) clearly highlight some advantages of the developed method. Analysis of the scores’ variances confirms that most of the evaluated parameters are significantly influential in the final scores. In particular, the classification of the structural weaknesses and the potential for pounding according to their severity proved effective to differentiate the buildings, something that was sought when developing the method because of the high incidence of these parameters in schools and because these are not properly considered in existing methods.