Étude paramétrique de la réponse non linéaire des ponts existants et de leur fragilité sismique à la perte d’appui

Abstract

The majority of existing bridges in Canada were built when earthquake engineering knowledge was insufficient to ensure adequate seismic performance. This has resulted in existing bridges with seismic deficiencies that need to be assessed. This thesis aims to evaluate the performance of existing bridges with respect to their risk of support losses associated with the displacement of their decks under the effect of seismic loads characteristic of Eastern Canada. A parametric study of the nonlinear response is performed with 12 bridge models generated based on an inventory of 733 existing bridges. The bridge models are subjected to a set of 14 historical and artificial accelerograms representative of the seismicity and the 5th generation of knowledge about the seismic hazard of regions of Eastern Canada. The seismic responses of the models analyzed allow to evaluate the relative influence of key geometric parameters on the structural vulnerability of existing bridges. It is expressed in terms of ductility and displacements associated with support losses or the collapse of the deck. This allows to quantify their impact on structural fragility or the probabilities of reaching or exceeding a level of damage. Fragility is expressed with curves defined according to damage limit state criteria associated with support losses for bridge decks and geometric parameters related to the minimum required support length. All the results obtained also allow to propose an equation for the prediction of the seismic displacements that can be used in a context of assessing the seismic vulnerability of existing bridges. It is also proposed to calculate the minimum required support length based on the period of the bridge instead of the geometric parameters. This allows to better identify the bridges with higher risk of support losses. Ultimately, this would allow to better identify the required and most effective interventions on road infrastructures in order to increase safety during major seismic events.

Date	27 Mar 2023
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Marie-José Nollet (Supervisor) & Amar Khaled (Co-supervisor)