ABSTRACT
Highway bridges can be subjected to extreme events (e.g., earthquake, flood). According to the United States Geological Survey (USGS) (2003), there is a 0.62 probability of a strong earthquake striking the San Francisco Bay Region (SFBR, California) during the time interval 2003–2032 (USGS 2003). Additionally, storm surge can cause significant flooding in coastal areas, which could overwhelm infrastructure systems. Consequently, life-cycle risk assessment of highway bridges under hazard effects is of vital importance. Further studies are needed in this area in order to develop design and performance standards for highway bridges that can handle more intense and frequent extreme events.
In this paper, hazard effects on highway bridges associated with flood and earthquake are investigated. The failure of highway bridges under flood considering scour effect is investigated. With respect to earthquake, the fragility curve is common used for bridge seismic vulnerability analysis (Dong et al. 2013). The conditional probability of failure of bridges under these hazards can be computed accordingly (Liang & Lee 2013). In general, the hazard effects can be mitigated and prevented if the structural performance with insufficient capacity is recognized and necessary repair and retrofit actions are performed. Additionally, the uncertainties associated with the hazard scenarios are considered in this paper.
Reliability-based performance indicators can consider uncertainties associated with loads and resistance, but are not able to account for the consequences incurred due to a structural failure event (Frangopol 2011; Frangopol & Soliman 2016). The performance-based assessment approach has gained increasing attention in the hazard evaluation process. Risk, defined as the product of the consequence of structural failure and the occurrence probability of the failure event, is becoming an important performance-based indicator in design and assessment of structural systems under hazard effects (Ellingwood 2005; Dong & Frangopol 2015). Within this paper, risk is integrated into the life-cycle assessment of highway bridges under multiple hazards and acts as a performance indicator that properly accounts for the probability of structural failure and detrimental consequences that this event causes. The life-cycle risk associated with multiple hazards is investigated and is illustrated on an existing highway bridge. The results presented in this paper can contribute to the improvement of the decision making process on infrastructure systems subjected to multiple hazards in order to better mitigate the life-cycle multi-hazard risk associated with these systems.
