"Towards Safer Bridges: Overcoming 2d Model Limitations and Reducing Flood Risks through Computational Fluid Dynamics"

Abstract

This paper outlines a modernised approach to estimate flood impacts at complex hydraulic structures using Computational Fluid Dynamics, the focus of this paper being the Gold Coast Highway Bridge over Tallebudgera Creek within the linear infrastructure project Gold Coast Light Rail Stage 4. Traditionally, 2D hydraulic flood models necessitate broad approximations of bridge parameters to estimate the impact of bridges on flood levels. This approach often lacks precise guidelines or best practices to reduce uncertainties, especially due to recent changes in bridge parameter application with the TUFLOW 2023 release. To address this gap, this study employed Computational Fluid Dynamics (CFD) to quantify flood level impacts to a high degree of accuracy. The findings from the CFD model were then utilised to update the existing 2D hydraulic (TUFLOW) model's bridge parameters. This integrated method significantly enhances the understanding of the potential impacts of bridge modifications on nearby properties. Subsequently, it allows for mitigation efforts to be strategically planned and implemented in vulnerable areas. The proposed Gold Coast Highway Bridge over Tallebudgera Creek has been used as a case study to demonstrate the benefits of CFD modelling compared to traditional methods. These findings underscore the potential of CFD in not only enhancing predictive models for flood impacts but also in shaping more effective flood management strategies.