In the Province of Québec seismic hazard is considered as moderate with the exception of Charlevoix region. However, the high density of population in urban areas has the potential to increase the level of seismic risk. In this context, the evaluation of seismic impacts on urban bridges is crucial to mitigation, emergency and recovery planning for transportation network. The degree of bridge damage determines the cost and time required for repairs and the level of post-earthquake functionality of the bridge determined by its capacity to carry traffic flow. For urban bridges network, potential damage is estimated by fragility analysis of typical prototype models representing bridge classes. The aim of this study is to propose a simplified fragility model to estimate potential seismic damage to bridges in province of Québec area. The Basöz and Mander’s methodology, a simplified approach implemented in Hazus software is adapted to seismic hazard and bridges properties in the region of study. Using characteristics of typical bridges in Eastern North America, such as geometrical, material and deck properties as well as the type of bearing systems, the simplified methodology is applied to estimate bridges capacity. Median and standard deviation of respective capacity values are combined with regional demand spectrum to calculate fragility curves for four damage states. Results are validated against literature fragility functions based on dynamic analysis of typical bridges in Quebec. This simplified fragility model is useful in a decision-making process to determine mitigation or post-earthquake priorities based on the mean damage factor of the bridges. The simplified method and the dynamics analysis both lead to leave bridges open after an earthquake with a 2 % probability of occurring in 50 years.
Diot, A. (Author),
Nollet (Supervisor) &
Abo El Ezz (Co-supervisor),
13 Jul 2020Student thesis: Master's thesis › Master in Engineering: Construction Engineering