Building Damage due to Riverine and Coastal Floods

Floods in both riverine and coastal zones can cause significant damage to infrastructure, including possible structural failure of buildings. Methodologies commonly used to estimate flood damage to buildings are typically based on aftermath surveys and statistical analyses of insurance claims data. These methodologies rarely account for flooding hydrodynamics, and thus do not differentiate between the damage caused by floodwater contact and those caused by floodwater velocity. A new stochastic methodology has been developed to estimate the direct impact of flood actions on buildings and to determine the expected damage. Building vulnerability is modeled based on analytical representations of the failure mechanisms of individual building components. The flood actions generated during different flooding events are assessed and compared to the resistance of each building component. The assessed flood actions include: hydrostatic and hydrodynamic forces, waves, turbulent bores, debris impacts, and time-dependent local soil scour. Monte Carlo simulation was used to synthetically expand the available building data, to perform load-resistance analysis, and to account for the uncertainty of input parameters. The primary result from this study is the expected flood damage to individual buildings, and it is expressed as a three-dimensional functions dependent on both floodwater depth and floodwater velocity. The results show how floodwater velocity can increase the magnitude of the flood damage outcome compared to those that solely consider water depth. This demonstrates the real need for considering floodwater hydrodynamics in the vulnerability assessment of buildings located in flood prone areas. Although the present study focuses on the vulnerability of reinforced concrete frame buildings with infill concrete-block walls, the methodology can also be applied to other types of structures. This methodology could serve as a decision-making tool to assist engineers and emergency management agencies to identify zones of high risk, and to implement the necessary preventive measures and mitigation strategies to minimize the adverse impact of potential flooding events.