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Nowadays terrorist attacks on civilian facilities have increased.Paying attention to the design of construction sites against the impact loads due to the explosion is important. Identifying the nature of explosive loads and their impact on the structure is one of the important issues to be studied. The explosion is one of the complex phenomena including high strain rate which highly affects the structural elements behavior. Regarding the fact that existing steel structures are typically designed based on conventional gravity and seismic loads, it is required that the performance of these structures be investigated under the explosion load. In this study, the evaluation of simple steel frame behavior with different dampers against explosive load and earthquake is investigated. Nonlinear dynamics analysis is performed on models with 3, 5 and 10 floor structures and in accordance with UFC 3-340-02 at two different levels of explosive charge, in the SAP 2000 software. The results show that between XADAS, friction dampers, Viscose in diagonal system, in the seesaw system, U-shaped with flexural and shear performance and proposed pipe dampers, The displacement dampers have the greatest impact in reducing the structure response. From this Friction damper and pipe and U-shaped with flexural function is more effective.

High-performance reinforcement concrete due to its ductility and higher energy absorption has many applications in the field of passive defence than the normal concrete. These high-performance materials can be used in many cases, such as seismic improvement of building members. In some cases the structural capacity is increased, which is called strengthening. Strengthening can be carried out by increasing the toughness and increase of resistance. In this study, the use of Explosion Proof concrete in order to protect the structural components (in this study: Weak-one Slabs). In this paper, four weak-one way slab that were strangled in various zones have been studied. The numerical modelling is proceeding in Abaqus / explicit. For modelling the behaviour of concrete, CDMP method has been used. The results of this study show that the energy absorption in the strengthened slab in the tense region has increased to seven times compare to other zone of strengthening. The use of fiber reinforced concrete has a significant effect on the increase of bearing capacity and the ductility of a one-way slab. In other words, the use of high-performance fiber reinforced concrete as a method for the strengthening of structural elements such as slabs will be effective in improving the behaviour of them, especially in the field of passive defence. Also, the maximum tolerable explosive load in compression, tensile and compression-tensile strengthed zone specimens was 1.3, 0.85 and 1.21 times compare with the reference specimen. The results of this study show that the use of high-performance fiber concrete laminates in all zones of the slab simultaneously, increase stiffness and reduce the deflection of the specimen.

one of the most important structural members that greatly affects the overall performance of the structure is the beam-to-column connection. Undesirable performance and failure of these connections can lead to local failure in the first step, and in the next step,a progressive collapse in the structure and falling. Therefore in this paper, the performance of two prequalified moment connections in the tenth chapter of the national building regulations of Iran against the external blast loads at a distance of 10 meters from a 1-story building in the Abaqus finite element software has been investigated. Thus, we first designed the structure with the seismic criteria, and then we designed the connections manually. Finally, we analyzed the connections in Abaqus finite element software against the blast loading. Results indicate a good response to the BFP connection compared to the WFP welded connection. As well as the percentage of failure of the WFP connection components relative to the percentage failure of the BFP connection components was more than triple. The results of this investigation show that the dominant failure mode is the failure of the joints due to the twisting of the column, consequently the screw connection due to better shapeability,gives a better response under the blast loading.

Today, with the increasing damages of explosion, it is of great significance to assess the performance of structures against such damages that established by explosive load. Accidental explosions exert great and intense dynamic forces to surrounding structures. Recently, composite shells have been used in structures to protect them against explosion which is due to its high resistance to volume ratio, flexibility and resistance to shock forces. Thus, it is essential to assess how structures protected by such materials behave against these forces. In this paper, we have used Abaqus software to analyze data pertaining the behavior of composite shells against explosive loads. We assessed the various parameters affecting the behavior of CRFP and E-Glass Epoxy and how they were affected by explosive load. Some of the parameters assessed include loading, curving rate, number of layers and size of interior angle. In practice, it is necessary to include openings in the composite shell, thus it is important to evaluate the effect of these openings on the behavior of the composite shell. The survey showed that use of the opening has fallen down shift. The reason for this phenomenon is reduction of area that effected by explosive load in composite shell