yasaman najjari

Using steel shear walls is one way to increase the lateral load-carrying capacity of reinforced concrete moment-resisting frames and have been gaining the interest of researchers due to their excellent performance in earthquakes and ease of construction. In these shear walls, connection to the frame and force transfer between the wall and the frame are of particular interest. In this study, the connection type of these walls and transfer of forces between them and the frame via bolts were examined and controlled using the ABAQUS software. For this purpose, a two-story concrete frame equipped with steel shear walls was evaluated after verifying the numerical model. The frame was assessed under two connection conditions: the ideal state, in which the shear wall is fixed to the beam, and the realistic state, in which these shear walls are attached to the beam using connecting plates on the beams and bolts at the top and bottom of the beam. To design the bolts, first, the prestressing force needed to prevent sliding should be calculated, according to which the prestressing force and the bolts can be designed. Also, the simultaneous effect of tension and shear should be taken into account in the bolts design. .After designing the bolt diameter and prestressing force, the behaviors of the frame were compared in both cases. The numerical analysis revealed that the load-displacement behaviors in both cases were almost identical. Furthermore, the stress in the bolts in the second state was found to be lower than their strength, indicating that the bolt design method is safe and suitable for transferring forces between the shear wall and the reinforced concrete structural frame in floors. Also, by designing the bolt and its prestressing force according to the method of this paper, it is ensured that no slippage between the concrete and the connection plates occurs until the end of loading.

The steel shear wall is an efficient lateral load-bearing system for steel and concrete structures. These members have been gaining interest because of advantages such as high stiffness, fewer architectural limitations, light weight, and lower footprint in plan. When shear walls are used in a semi-continuous state in the structure, it is possible to consider an opening in the span without creating a hole in the shear wall. In the present study, numerical research was performed on the behavior of concrete frames containing a steel shear wall with a semi-continuous connection to the frame. First, the numerical model was validated using an experimental specimen. Then, by performing 33 nonlinear static analyses, the effect of the wall width and thickness on the seismic behavior of concrete frames was investigated. Similarly, the width of the wall was considered to vary from 10 to 110 cm in 11 cases. In addition, the shear wall thickness was examined in 3 cases of 1, 2 and 3 mm, respectively. The outputs of the frame included energy loss, lateral stiffness, strength, and ductility of the frame. To calculate the shear wall stiffness, a formula was presented using the curve fitting technique based on numerical results. By using this formula, the wall stiffness can be estimated with good accuracy using its width and thickness. After comparing the results, it was observed that when the shear wall width in the frame was selected correctly, not only the stiffness and lateral strength of the frame increased, energy loss and ductility of the frame were 2.7 and 1.7 times those of the plain frame, respectively. By considering the ratio of the shear wall width to the frame span equal to 0.38, a proper width can be obtained for the shear wall.