Effects of river shapes on structural damages to buildings in flood-prone regions

Flooding is one of the consequences of climate change that could lead to damage or demolition of structures and cities. For this reason, investigating the effects of floods on structures from different aspects is vital. One of the most important issues is the resilience of cities and structures against natural hazards, including floods. This article is one of the first attempts and a big step toward flood-resistant buildings and cities. Therefore, during a field investigation as a case study (the 2019 flood of Poldokhtar in Iran), various factors have been examined: (1) the effects of straight and meandering rivers on the flood damages on engineered and nonengineered buildings, (2) the effects of flooding on infill walls, (3) the critical factors for the development of cities, and (4) the identification of performance levels and appropriate measures toward flood-hazard-resilient buildings. Because of this, the mentioned factors have been investigated during the case study. Then, buildings have been classified based on their damage and performance. After that, the damage levels of the structures are defined, and the actions that are required to be taken for each of the damage levels are described. Then the flood damage caused to the buildings in five different areas of Poldokhtar has been evaluated and the reasons have been examined. The results indicated that the river's shape is one of the vital features in resonating damage. Buildings in the river arches have suffered more damage than other structures due to the flood. This issue should be considered in the development path of resilient and resistant cities and structures. The results showed that it is crucial to pay attention to the following factors in the development of flood-resilient cities: the shape of the river, predicting the flood path, and the appropriate location of centers that played a vital role in postflood crisis management, accurate calculation of river basins, structural and nonstructural elements of buildings, and preparation of flood risk map. It is not advisable to build residential buildings in river basins that have a high risk of severe flooding. The amount of engineered buildings' flood damage was less than that of nonengineered buildings. Also, flood damage to infill walls consisting of sand lime bricks or dry-pressed bricks was much less than that of infill walls made of hollow clay bricks (perforated bricks or clay air bricks). Finally, some recommendations for flood-hazard-resilient buildings and cities have been provided.