Investigation of Progressive Collapse Occurrence under Main and Aftershocks Earthquake

When a critical load such as (floods, explosions, earthquakes, or fire) enters the structure, the severity of the critical load depends on the strength of the load-bearing elements of the structure, whether the structure is completely destroyed or remains intact. Or some members are out of basic mode. Progressive failure is a nonlinear phenomenon that starts from the damage of a part of the structure and ends with the entire structure and its total destruction. Progressive failure is usually in the structure due to the loss of one of the main members, a column. A column in the structure at the node where the column is removed causes a location change with a seismic nature. This change of location has occurred, and the dynamic analysis's explanation of the force caused by removing the column on other elements is desired. It is checked that the side columns of the removed column can bear the explained load, or after explaining the load on the columns, they are destroyed due to buckling and breakage. This study uses the Alternative Path (AP) method, independent of the failure factor proposed by GSA and DoD. Nonlinear dynamic analysis is also used. Two types of column removal scenarios have been used. Since the AP method is independent of the failure factor, two concentrated loads with a very large size and opposite direction (more than the capacity of the column) are instantly entered into the ground floor column (shearing the column) and cause column failure. The research was conducted in three models on the 5, 10, and 15 floors, and the results are discussed.