Comprehensive seismic risk assessment of mountainous road networks under concurrent impact of earthquakes and water presence

Abstract

Seismic risk assessment of road networks is crucial for ensuring infrastructure resilience and enhancing informed decision-making and retrofits in earthquake-prone regions. This study aims to evaluate the seismic risk associated with retaining walls and cut slopes in three districts of northern Greece, with a particular focus on the impact of water presence. A comprehensive exposure model is developed, identifying key components along the examined road axes. Existing probabilistic seismic hazard analysis results are employed for all regions, supplemented by deterministic analyses with seismic scenarios of 475- and 955-year recurrence periods for Xanthi regional unit. Novel fragility curves for gravity retaining walls and cut slopes are proposed, while existing ones are applied for reinforced concrete retaining walls. Risk analyses are conducted for peak ground acceleration (PGA) and peak ground velocity (PGV). The probabilistic analyses outcomes reveal the critical importance of considering water presence in seismic risk assessment, identifying districts with higher level of seismic risk. Scenario-based analyses indicate that, while all elements are likely to experience minor damage under dry conditions, the presence of water leads to moderate and extensive damage for several cut slopes and retaining walls. Finally, the study emphasizes the need for targeted mitigation strategies to enhance the resilience of road infrastructure.