One of the issues that has been a lot of attention in recent years in the passive defense field is the issue of progressive failure in the structures. Progressive deterioration can be defined as a chain reaction or failure propagation in which, under a particular cause, local injury occurs in a relatively small area of the structure and, in the event of this local injury, extends to other parts of the structure and ultimately leads to general failure The structure ends. In other words, in some cases, the local failure of the member does not remain in place and is distributed throughout the structure. Possible risks and abnormal loads that can lead to a breakdown include design, construction, fire, gas explosion, accidental overrun, car crash, bomb explosions and more. Design methods for rolling resistance failures in structures are intended to provide the capacity of a structure against unusual loads, including direct and indirect design methods. Alternative Route Method is the most important direct design method that has been accepted as the most practical method for assessing the vulnerability of new or existing buildings in studies related to the design of resistant structures for this event. In the alternate routing method, it is assumed that the member in question will be removed from the structure as a result of an unusual and severe load, then the ability to bridging the structure to the deleted element is examined.
In this research, we evaluate the effect of frame lengths on the progressive erosion of concrete structures with a framing frame system. For this purpose, different plans of concrete structures with a frame of frame are considered, and then considered different progressive failure scenarios (different states of removal of the column), and nonlinear dynamic analysis (time history) and analysis of the structure, structure response including performance levels The structure is investigated.