A safety evaluation procedure against multi-hazards for a slightly damaged bridge is proposed. To consider the inherent uncertainty involved, a probabilistic approach is adopted. The uncertainties in structural responses for a given seismic excitation and in scouring depth for a given flood with a specified period are included in the proposed procedure. To further address the scour effect, variation of scour depth among different piers is considered. Joint failure probability is used to measure the bridge safety against multi-hazards. This framework consists of three major components: the seismic and scour hazard curves, non-linear time history analyses and multi-hazard failure analysis. A multi-span continuous bridge located in Nantou District of Taiwan is used to demonstrate the proposed procedure. Based on the analyzed results, collapse failure probability of a bridge with slightly damaged condition is 24 times than that of a non-damaged bridge. It is seen that a bridge with slight damage has a significant effect in its performance and should draw more attentions.

A safety evaluation procedure against multi-hazards for a slightly damaged bridge is proposed. To consider the inherent uncertainty involved, a probabilistic approach is adopted. The uncertainties in structural responses for a given seismic excitation and in scouring depth for a given flood with a specified period are included in the proposed procedure. To further address the scour effect, variation of scour depth among different piers is considered. Joint failure probability is used to measure the bridge safety against multi-hazards. This framework consists of three major components: the seismic and scour hazard curves, non-linear time history analyses and multi-hazard failure analysis. A multi-span continuous bridge located in Nantou District of Taiwan is used to demonstrate the proposed procedure. Based on the analyzed results, collapse failure probability of a bridge with slightly damaged condition is 24 times than that of a non-damaged bridge. It is seen that a bridge with slight damage has a significant effect in its performance and should draw more attentions.

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