Risk assessment of bridges under multiple hazards in operation period

Over the past several decades, the number of disasters around the world has been amplified. Moreover, the impacts of disasters on communities have attracted extra attentions, requiring efficient measures of disaster management. Similarly, safety problems of bridges have become public topics since bridges represent essential parts of highway infrastructure that have been exposed to multiple hazards during their life cycle. In this paper, a novel framework of disaster risk assessment is proposed, by combining Fuzzy Analytical Hierarchy Process (FAHP) with fuzzy knowledge representation and fuzzy logic techniques into a single integrated approach. A survey about collapsed bridges in the past few decades has been conducted. From this investigation the potential hazards have been identified. The FAHP approach is applied to ranking risk factors since it is more systematic, accurate and effective than traditional AHP. Risk indicators, the probability of occurrence, the impacts of disasters and disaster consequences are analyzed from expert opinions. The bridge risk is computed by implementing fuzzy logic tools on the risk factors and their parameters. The proposed method is practical and efficient for a quick and reliable multi-hazards risk analysis and assessment of bridges. Based on the level of disaster risks to which the bridge is exposed, an appropriate bridge safety management plan is required to reduce or prevent the effects of the disasters. A case study is examined for a bridge in Tianjin, People's Republic of China. The results illustrate the applicability of the proposed risk assessment method of bridges under multiple hazards.