Flood hazards are becoming increasingly prevalent in several countries due to multiple reasons including global climate change. Bridge failure statistics indicate that over the last couple of decades, flood-related issues such as scour, hydrodynamic forces, and debris forces have caused the maximum number of bridge failure cases worldwide in comparison with other natural hazards. Such observations clearly demonstrate the need for consistent code provisions among different codes to design highway river-crossing bridges against the growing demand from flowing water during floods. The current study performs a comprehensive review of six international bridge design codes that provide guidelines to calculate flood-induced forces for design of bridges against flood. Following these provisions, flood loads on various components of two bridges with different geometric configurations and material properties are estimated under a number of flood cases. Finite-element (FE) models of the bridges are developed to analyze them for estimated flood loads. The outcomes revealed that obtained bridge response following these six codes varied over a wide range. A comparative assessment among these response values demonstrated the disparity of these code provisions for flood design of bridges

Extreme floods can cause water level to rise above bridge superstructures. Following worldwide statistics on hydraulic bridge failure, it becomes essential to generate a comprehensive knowledge base to predict probable bridge failure scenarios under future floods and to identify appropriate countermeasures for flood risk mitigation. With this objective, the study here develops a numerical framework for systematic evaluation of forces on vulnerable bridge components during floods and to understand the global response of inland river-crossing bridges under flood hazards. Computational fluid dynamics (CFD) simulations are performed to calculate hydrodynamic forces on superstructure of a representative bridge for different inundation levels and flood velocities resulting from varied intensity flood events. Hydrodynamic forces on piers and scour depths around foundations are estimated for flood cases considered here. Knowing the forces and scour depths, finite element bridge models with and without scour are developed and analyzed to apprehend its global response and progressive failure under various combinations of water height and velocity. Further, regression relations are proposed to project component-level responses based on which damage state of the bridge under future intense flood events and fragility characteristics could be predicted. Thus, results enable identifying key factors to reduce flood vulnerability of inland bridges.

Global bridge failure statistics highlight that hydraulic actions, particularly hydrodynamic forces and scour, contribute significantly to bridge failures. Previous incidents reveal that extreme floods can lead to complete inundation, resulting in collapse of bridges. Recent studies underscore the vulnerability of the superstructure during flood events. Despite prior research, understanding the impact of flood-induced hydraulic forces on diverse bridge components, particularly in life-cycle analysis with gradual degradation from chlorideinduced corrosion, remains limited. This study utilizes computational fluid dynamics (CFD) simulations through ANSYS Fluent. It evaluates hydrodynamic forces on superstructure of a typical RC riverine bridge, accounting for gradual performance degradation due to corrosion. The study considers flood-induced scour and conducts finite element (FE) analyses at different stages of the bridge’s lifespan, offering insights into its life-cycle performance under diverse flood scenarios. These findings inform strategies to mitigate the enhanced flood vulnerability of inland RC river bridges facing future intense flood events.

Riverine flood is one of the critical natural threats to river-crossing bridges. As floods are the most-occurred natural hazard worldwide, survival probability of bridges due to floods must be assessed in a speedy but precise manner. In this regard, the paper presents a reliability-based approach for a rapid assessment of failure probability of vulnerable bridge components under floods. This robust method is generic in nature and can be applied to both concrete and steel girder bridges. The developed methodology essentially utilizes limit state performance functions, expressed in terms of capacity and flood demand, for probable failure modes of various vulnerable components of bridges. Advanced First Order Reliability Method (AFORM), Monte Carlo Simulation (MCS), and Latin Hypercube Simulation (LHS) techniques are applied for the purpose of reliability assessment and developing flood fragility curves of bridges in which flow velocity and water height are taken as flood intensity measures. Upon validating the proposed method, it is applied to a case study bridge that experiences the flood scenario of a river in Gujarat, India. Research outcome portrays how effectively and efficiently the proposed reliability-based method can be applied for a quick assessment of flood vulnerability of bridges in any flood-prone region of interest.