Evaluating disaster resilience of bridge infrastructure when exposed to extreme natural events

摘要

Disasters can be natural or human made, predictable or totally unexpected and can be of any size. However, they cause considerable damage to the built environment. Disaster resilience of a society mainly depends on the physical robustness of structures and infrastructure and resilience of the community. This research paper focuses on the damage caused by the recent floods in Queensland, Australia on the bridge infrastructure. Bridges in one council area were selected as a case study. For the damaged bridges, data such as level of damage, material used in these bridges, type of bridge (girder/precast/insitu), age of the bridge, annual average daily traffic, heavy vehicles and inspection data before and after the flood were collected and analysed. In structural engineering, vulnerability is a term used to define the damage tolerance of structures.This case study is used to find a relationship between the collected data and the vulnerability of the bridges. It is interesting to observe that there is an inverse relationship between the age of the bridge and the damage level. The reasons for this could be due to different construction practices adopted in the past or they had been rehabilitated after previous disaster event. However these reasons should be further analysed for confirmation. It can be concluded that the bridges on arterial roads, which are normally designed for heavy load platform loadings, are more resilient than those on the rural collector roads during an extreme flood event. However since arterial roads may have some redundancy during a flood event, rural roads may become the only means of traffic movement. The resilience of the community will depend on the resilience of the bridges on rural roads which are at the moment vulnerable in extreme flood events. Therefore when classifying roads for design, it is necessary to consider the impact on the community during and after an extreme event.