In the event of an earthquake occurring in steel Frames structures, if the lateral load-resisting system is a moment frame structure, these beams will dissipation of energy and developed plastic hinge in the beam, but this requires a strong connection that must be made in the design of the structure. A zone of beam and column connection exposed to flexural and shear stresses. This zone is considered as a sensitive area of the bending frame; if this area does not do its job properly, the transmission of force between the beam and the column is not properly executed and the structure will be damaged seriously. The reputable regulations of the world have considered certain criteria for this area and they are called connection springs. In this study, four models were designed to examine the force mechanism of this section and the behavior of this part is investigated. Contrary to expectation, a huge share of the cut is transmitted in scarves and underpants. In the next step, a model is designed to give the source of the connection a surrender. In this case, the shearing sheet transmits a negative cut into scarves and cufflinks.

The bending connections Beam to the Cruciform Column in Iran are increasing. Normal columns, such as columns I and H, have the ability to connect two Beams. Cruciform Columns the ability to connect 3,4 Beams. This requires a strong connection that should be considered in the design of steel structures. One of the members of the connecting Panel Zone. In the design Codes, the relationship between the yield point and final point of the panel zone in the H columns was presented.The purpose of this study is to investigate the behavior and strength of panel zone in cruciform columns. For this purpose, the modeling has been used by ABAQUS software. In the first step, numerical modeling has been confirmed with laboratory verification. In the second step, by designing and modeling 20 numerical models, the strength of the panel zone is investigated. According to the results of models, it was found that for the Cruciform Column it is not possible to use the relations provided for H columns. As a result, there are relationships for determining the strength of panel zone in cruciform columns in an elastic and non-elastic state, provided that the rotation of the coupling fence is not quadrupled above the elastic limit.

Shear walls are one of the most lateral- forces resistant systems which have been nicknamed "shear walls" due to their high shear force absorption. Bending deformation of these structures is noticeable which results in great tensions at the foot of the wall. These walls are divided into two groups of reinforced concrete and steel walls and their behavior are different from each other. Reinforced concrete shear walls have high out- of- plane stiffness which prevents them from buckling but steel shear walls have low out- of- plane stiffness and their behavior is affected by diagonal traction fields which results in shear capacity reduction. In order to prevent these walls from buckling, steel plates are connected to concrete panels by means of shear studs. Coupling of steel shear walls changes their behavior and steel plates reach their ultimate capacity. Therefore, in this study, nonlinear static behavior and seismic parameters of composite shear walls system have been investigated. At the beginning of the research, a sample of the laboratory model has been verified to ensure the modeling of the composite shear wall in the nonlinear behavior range. In the next study, a double-skinned steel frame system and five-story compound shear walls were designed in a panel based on a reasonable behavior coefficient. In ABAQUS software, non-linear static modeling and analysis was performed and seismic parameters This system has been calculated for its behavior coefficient and shape. The results of the seismic parameters derived from this model are in good agreement with previous studies.

According to researches and experiments conducted by researchers, it is accepted that shear walls have significant structural parameters such as lateral stiffness, shear capacity and energy absorption. These walls are known for their shear force due to the shear force absorption, while flexural deformations occur, and stresses from the bending anchor at their feet are remarkable. Now, if we connect two adjacent and separate shear walls together with very difficult towed beams, the strength and behavioral properties of these walls will change greatly. So, to clarify this, at the beginning of the present study, the relationships between the elastic analysis of the system are reviewed in a continuous method. In the next study, a 10-story coupled shear wall system is compared with the results of ABAQUS software based on the continuous method of elastic analysis. According to studies, the lateral displacement in the system of the coupled shear walls is increased and the lateral stiffness decreases. Also, the bending anchor in the shear walls is sharply reduced relative to the uncoupled shear walls, but the shear force does not change in each of the walls, but very large shear force are formed in the coupled beams, which are Axial force is transmitted to the walls. In general, the presence of coupled beams in the system of uncoupled shear walls significantly reduces the stress at the foot of the walls and makes the lateral deformations in the walls to be flexed to the shear.