Intégration des effets de sites à l'évaluation de la vulnérabilité sismique des ouvrages d'art à l'aide d'une plateforme de système d'information géographique (SIG)

Abstract

Southeastern Canada experiences about 600 earthquakes per year. While seismic hazard is generally moderate in eastern Canada, the density of the population in urban areas makes it the second-largest seismic hazard area in Canada. The study of the vulnerability of the seismic risk aims to evaluate the potential damage to structures in order to prioritize the interventions following an earthquake or to plan mitigation strategies. These tools are generally index-based, such as Caltrans, NYDOT, SETRA or the scoring procedure used in the province of Quebec (MTMDET). These scoring procedures consider the structural vulnerability of the exposed structures and, to qualify the seismic tisk, the seismic hazard index is defined from the probable acceleration at the site for a given recurrence period. In general, the site amplification effect of seismic waves is integrated with the seismic hazard. However, the specific geotechnical information at the site of the structures is often not available, making the resulting seismic risk of vulnerability score less representative. Besides, few index-based methods are taking into account the induced effects, such as landslides, rock falls or the liquefaction potential of soils. This study proposes to develop sensitivity scales for site effects to better define the seismic hazard in order to integrate it to scoring procedures for the evaluation of the seismic risk for bridges and overpasses. This work is part of a project to study the seismic vulnerability of bridges and overpasses for the Saint-Lawrence valley, taking advantages of Geographic Information Systems (GIS), for a better consideration of the seismic hazard in the analysis of the seismic risk to these infrastructures. The aim of this project is to develop a sensitivity scale to the amplification effect and induced effects (landslides, rock falls or liquefaction potential) based on hydrological, topographic and geological cartographic data (GIS). These sensitivity scales could then be easily integrated within the various scoring procedures for seismic prioritization. The amplification sensitivity scale was validated by ambient vibration measurements taken at the sites of several bridges to capture the natural frequencies of the ground and bridge. An inventory of landslides in the St. Lawrence Valley validates the landslide sensitivity scale. These scales are then integrated within the index-based procedure used in Quebec (MTMDET). Moreover, a succinct evaluation of the impact of the loss on the road network of some bridges is studied in order to illustrate how softwares can help to prioritize the interventions on bridgesin a context of seismic planning and mitigation strategies.

Date	12 Sept 2018
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Marie-José Nollet (Supervisor) & Amar Khaled (Co-supervisor)