Bridges

The objective of Austroads project ABT1925 is to develop new guidelines for flood response, bridge management and operational requirements during extreme weather events. The project will produce a new Austroads guideline for flood recovery, assessment and risk management for bridges and an update to the Austroads Guide to Bridge Technology Part 8: Hydraulic Design of Waterway Structures (AGBT08) to incorporate best practice for managing the risk of bridge flooding and scour and improving resilience to flooding.

This paper highlights the development of a scour risk assessment method, detailed scour impact evaluation and operational requirements during extreme weather events as developed for the Austroads project.

The development of the scour risk assessment includes the evaluation of the current state of local industry practice, focusing on commonalities and disparities in the scour risk management approach to establish vulnerability criteria, methods and guidelines that will determine the scour potential and risk prioritisation for each bridge.

The detailed scour impact evaluation aims to quantify the scour impact to establish appropriate mitigation measures through flow estimations, scour depth predictions, intervention and treatment options. It incorporates the 2019 Australian Rainfall and Runoff Guideline and the updated Austroads Guide to Road Design Part 5: Drainage – General and Hydrology Considerations (Australian Rainfall and Runoff Alignment).

The operational requirements during extreme weather events involve a broad review of local and international learnings for flood response, best industry practice and stakeholder consultation with transport agencies, network operators and owners and address the operational management of bridges during and post-flood events. It also involves a review of government strategies and policies that addresses resilience of infrastructure to environmental changes, emergency response and disaster management operations of critical infrastructure.