nonlinear analysis

The study of the simultaneous impact of earthquakes and explosions on structures has been considered by researchers in recent years. On the other hand, irregular effects in structures lead to increased complexity in predicting the behavior of structures. Thus, in this article, for the first time, the simultaneous impact of earthquakes and explosions on irregular structures is investigated. For this purpose, an 8-story three-dimensional concrete structure is modeled and analyzed using OpenSees software. The modeled structure is first analyzed without dampers against the combined effects of an explosion with an earthquake. In this paper, the combined effect of explosions with 8 different earthquakes has been investigated separately. Then, in the next step, the placement of TADAS dampers and their specifications are designed in such a way that the performance level of the structure against this type of loading reaches the level of Immediate occupancy (IO) performance. Based on the results obtained from nonlinear static analysis of two structures without dampers and equipped with dampers, it was found that the use of dampers in this structure causes the capacity of the structure to increase by about two times. Also, based on nonlinear dynamic analysis of structures, it can be concluded that the use of this type of damper can reduce the drift and displacement of the structure by more than 60%. Also, using the correct arrangement of these dampers in irregular structures can reduce irregular effects.

Earthquake and explosion are destructive dynamic forces. These forces can cause severe damage to the structure due to the time-dependent nature of the impact. One of the most important parameters for checking the stability of structures is the study of their buckling modes. The stability check has a direct relationship with the critical load of the columns. In this paper, the effects of simultaneous explosions and nearearthquake earthquakes on the stability of structures are investigated. The purpose of this research is to numerically simulate the state that earthquake-induced vibrations cause explosives to explode near structures. Therefore, the dynamic and buckling behavior of structures under the effects of earthquake and explosion have been investigated. In this article, the explosion enters the structure in three phases with the earthquake simultaneously. These three stages include before the earthquake, at the time of the earthquake and after the earthquake. In this regard, in this paper, structures are affected by internal and external structural explosions and the simultaneous effects of earthquakes. This article has shown that the most critical situation is when the vibrations caused by an earthquake trigger an explosion during its strong movement. The results of this paper show that the combination of explosion and earthquake is not very effective if the explosive is more than 500 kg TNT. In fact, earthquakes in this case have little effect on the nonlinear response of the structure. In this paper, it is shown that the effects of P-Delta consideration do not have much effect on the structure response. Based on the results provided for different explosions and earthquakes, it can be seen that the combination of explosion and earthquake has a greater effect on dynamic analysis.