Deriving damage indices for concrete girder bridges subjected to flood loading

It is noted that the intensity and frequency of disasters have increased over the past few decades and the damage to infrastructure after a natural hazard has consequently increased. The recent flood events in Queensland, Australia had an adverse effect on the country's social and economic growth. Due to climate change impacts, it is reported that the frequency and intensity of flood events have increased noticeably in recent years. Failure of transport infrastructure after a flood event significantly affects the community, road authorities and wider stakeholders. Bridge structures are often vulnerable to flood events due to their proximity to water ways and the resultant direct impact of flood on structures. In identifying strengthening needs for vulnerable bridge structures, a damage, flood intensity relationship is required. The paper has reviewed different bridge design codes used over several years in Australia for designing the bridges and the method of design for flood loading is identified. Various failure mechanisms of bridges due to flood events have been investigated through analysis of case studies and the most common failure mechanisms of the bridges in Queensland as the result of the 2011 and 2013 flood events have been identified. A case study bridge has been modelled using the general purpose finite element software, ANSYS. The damage to bridges due to impact of floating items under different flood scenarios have been investigated. Damage curves have been generated for the case study bridge under different flood intensities.