Performance of Bridges with Damaged Elements in Extreme Flood Events

Abstract

Recent floods in Southeast Queensland, Australia have caused detrimental impacts on the social, environmental and economic aspects of the country. Bridges are considered as critical infrastructure because in a time of a disaster and during its recovery stage, bridges provide access for emergency services to flood affected communities. A community has the potential to be isolated if a bridge crossing a river or creek is damaged by flooding. Therefore it is important to understand the impact that flooding has on bridges so that they can be made less vulnerable to damage from these extreme events. In order to analyse the effects of flooding, a finite element model of a case study bridge was created using the software package Strand7. The flood loads determined by the Australian Standards were applied to a case study bridge (Tenthill Creek Bridge near Gatton in the Lockyer Valley, Queensland). Damage to the bridge was also simulated by adding weakened elements to the main structural elements of the bridge. In order to compare different load cases and damage scenarios performance indicators were used to assess the vulnerability. It was found that a damaged girder subjected to log impact loading produced the maximum stress in the bridge.