Comparison and Assessment of Light Vehicles Damages Based on Stability Theories in Floodwater(Case Study: Shiraz Flood)

Evaluation of damages caused by flash floods in urban areas is one of the most important concerns after their occurrence. Like other urban elements, vehicles suffer damage that should be considered for managing urban floods. The damage values ​​in most car damage models in flood are presented with the assumption of their stability and purely in terms of depth, while the flood velocity as flood important variable is also effective on the severity of damages. In the present research, while evaluating the eight theories presented in the Australian Rainfall and Runoff Guideline (AR&R), an attempt is made to provide the best theory to provide a simple and accurate algorithm for determining the damage to sedan vehicles in flood as a function of depth and velocity.

To achieve the goal of this research, the formulas and diagrams of the stability limit of eight theories presented in AR&R were evaluated and after deleting one of the theories and modifying the Melbourne Water presented in 1996 and DPW presented in 1986 formulas, the stability map of the sedan cars in Darwaze Quran flood on March 25, 2019 in Shiraz was produced for seven theories proposed in this guideline. Subsequently, by combining the stability limits of each theory with the HAZUS-MH depth-damage diagram and zoning below the stability limit diagram as stable areas, the risk map algorithm for stable sedan vehicles was provided separately for each theory. In the following, the risk map in the adjacent parking area of ​​the water pool upstream of the Quran Gate of Shiraz for each theory and, with their help, the total damage for the Pride_131 was calculated as a common vehicle in Iran. Finally, the measures of maximum damage, as well as the total damages were obtained from each one.

One of the main and most important results of this research is providing an algorithm for determining the damage of the sedan vehicles in a certain range of depth and speed for each of the theories proposed in AR&R, which were used for producing the risk map. In addition, the total damages for the Pride-131 as an index car were calculated by the proposed algorithms. The minimum damage was obtained by using AR&R (1987) theory algorithm equal to 10 billion and 265 million toman and the maximum amount of damage was obtained by using achieved by using AR&R (2011) theory algorithm equal to 14 billion and 32 million toman.

It was found that the use of the depth of flood as a hydrostatic index, which is now the criterion for calculating car damage, is not accurate enough and it is better to use velocity and depth composition as a hydrodynamic index for this purpose. At the same time, it was proved that among the other theories, the relation and the final limit of stability presented in the AR&R (2011) theory to provide a model for determining the damage to small and light vehicles in the flood as a function of depth and velocity has better and more reliable results. It is worth noting in order to achieve the more accurate damage amounts of vehicles in flood, more theoretical and experimental studies considering different types of vehicles are essential.