Examining the changes in the dimensions of the structure and its effect on the compressive zone and resistance functions against progressive collapse

Today, one of the most important topics studied and researched in the construction industry is predicting how buildings will be damaged when accidents such as earthquakes or explosions occur. These accidents cause severe damage and lead to the destruction of some of the main members of the building. Progressive collapse is an example of a process that first leads to initial local damage and then leads to destruction of adjacent members or the entire structure. Due to the insufficient knowledge and information and the lack of a detailed analysis method that can consider the effective factors and mechanisms of resistance to progressive collapse, a more informed design is needed to ensure better performance against accidents. Since the proposed methods require high costs and time-consuming, more research is conducted in this field to better understand the influencing factors. In this research, five models of reinforced concrete frames with different dimensions and structural characteristics have been investigated under progressive collapse. This study has been done with the scenario of removing the middle column in progressive collapse based on nonlinear and numerical analysis using Abaqus software. As a result, by obtaining the area of the compressive areas of the concrete beam using the displacement force diagram, the optimal ratio of 5 was obtained by dividing the dimensions of the beam length by its height for dimension design. It can prevent accidents by more accurately predicting resistance mechanisms and compression areas of reinforced concrete beams of various structures. This ratio was investigated among these 5 models.