List of Articles رفتار لرزه‌ای

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  1 - Seismic Behavior Upgrade of Steel Moment FramesUsing Viscous Dampers and Determination of Their Proper Damping Forces
  seyyed Mehdi Zahraei Omid Mohammadi
  Energy dissipation systems have been broadly used in structures during the recent decades in order to reduce earthquake and wind forces as well as reduction of structural lateral drifts within the code limits. Viscous damper is considered as one of the energy dissipatio More

  Energy dissipation systems have been broadly used in structures during the recent decades in order to reduce earthquake and wind forces as well as reduction of structural lateral drifts within the code limits. Viscous damper is considered as one of the energy dissipation systems which are classified as velocity-dependent dampers among passive control systems and have been paid attention and their further detailed properties taken into account by many researchers. Viscous damper consists of a piston with some orifices inside the cylinder which contains highly viscous fluid. Energy dissipation of this damper is through pushing viscous fluid out of the orifices. These are two types of these dampers: linear and nonlinear from which linear type with velocity power of one is more practical. The structural damping force is usually set according to the procedure described in FEMA273 and are optimized by three controlled modes of displacement, velocity and acceleration. This study examines the effect of adding viscous dampers on seismic behavior of steel moment frames. For this purpose, three steel moment frames of 1, 3 and 6-story all in 3 bays, with viscous dampers having power factor of 1, 0.8 and 0.6 are selected. These sample structures are subjected to the nonlinear time history analysis under the El Centro, Kobe and Northridge earthquakes, and their response including displacement, acceleration and base shear is compared in two cases of with and without viscous dampers. Finally, regarding nonlinear time history analysis results based on the structural behavior in three modes controlled by displacement, velocity and acceleration, proper damping forces are specified as 94.7, 240.1 and 557.1 kN respectively for one, three and six story structures based on maximum acceleration and base share obtained from FEMA273. Manuscript profile
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  2 - Improving the Seismic behavior of Repairable Systems with a Cradle Mechanism in Irregular Mass steel Braced Buildings in Plan
  Mohsen Mohajer Tabrizi Abbas Akbarpour Abdul Reza Saroqd Moghadam Maryam F. Nezamabadi Mohammadreza Adib Ramezani
  10.30495/civil.2023.701043
  This research has investigated the improvement of the seismic behavior of repairable systems with a cradle mechanism in steel braced buildings with irregular mass in plan. A new method is used to find a suitable method in a building with a regular plan with asymmetric m More

  This research has investigated the improvement of the seismic behavior of repairable systems with a cradle mechanism in steel braced buildings with irregular mass in plan. A new method is used to find a suitable method in a building with a regular plan with asymmetric mass distribution, in order to reduce the adverse effects of the structure and to quickly repair the damage caused to the structure after a strong earthquake. In this method, by creating lifting conditions at the base of braced bay columns and by using energy-dissipating devices in this part, energy absorption and consumption are transferred to this part of the structure and prevent damage to other parts. Based on the results, the effect of taking into account the effects of vertical and horizontal earthquakes in different mass irregularities of structures in the seismic performance of low-rise structures was determined. Also, the irregularities in the numerical model of the structure have a significant effect on the IDA curves. As the height of the structure increases in the four failure modes, the mean probability of fragility of the structures occurs at a lower Sa, which means that the vulnerability of the structure increases. Also, with the increase in height, the slope of Sa reduction in four failure modes becomes milder, and the fragility curves for two IO performance levels and CP performance level have been obtained for all 6 structures. Considering the effect of irregularities, they are significantly effective in the structural failure of structures, so that considering the effect of these irregularities in mass distribution can lead to an increase in the probability of structural failure. Manuscript profile
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  3 - Study on Cyclic Behavior of Stiffened Steel Shear Walls with Semi-rigid Joints to Steel Frame
  sina shirjang Ahmad maleki
  With increasing research on the operation of the shear walls of the steel walls and increasing the reliability of their operation, the use of these walls has been noticeably expanded, especially in the United States and Japan. Given the relatively comprehensive understa More

  With increasing research on the operation of the shear walls of the steel walls and increasing the reliability of their operation, the use of these walls has been noticeably expanded, especially in the United States and Japan. Given the relatively comprehensive understanding of the behavior of these walls, design rules have now begun to provide design rules for these walls. The basis of the performance of these structures is based on the operation of the diagonal tensile field after the buckling of the steel plate. Simple implementation is based on the technical advantages of the system without the need to acquire new skills, reduce the dimensions of the foundation, increase the perceptibility of the lateral structure of the structure, reduce the dead load, and, in the meantime, the economy of this system in counteracting the steel frame framing system is considered as the main advantages of this system. Gets The steel shear wall is a new side-impact resistant system that has better performance than other side-impact resistant systems. Considering the importance of using such structures, there is a need for study in this field. In this study, prior to examining the performance of joint wall joints, to verify the numerical results, we verified the laboratory sample and after evaluating and assuring the results of the modeling, 12 steel wall panels with Abaqus software were used. In these samples, parameters such as wall thickness, geometric characteristics of beams and columns, and the degree of opening of the corners of the sheet are investigated. The results of this study showed that with increasing the cross-section of the columns, the stress distribution was uniformly distributed on the surface of the sheet and the entire surface of the sheet buckling to the outside of the sheet, while in the case of an increase in the cross section of the buckler, It is visible on the sheets. However, in the event of an increase in the thickness of the wall plate, the amount of non-elastic strain created is less and is approximately limited to the lower parts of the first sheet. With a 20% increase in wall thickness, the bearing capacity and hardness of the samples increased by an average of 18%, and by increasing the opening rate, from 5 to 15% of the bearing capacity decreased by about 20%, and the amount of strain of plastic in the form of a diameter in the sheets It is visible at the site of the sheet attachment to the perimeter bore in the portions of the columns. Manuscript profile
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  4 - Seismic Performance Evaluation of Composite Steel Shear Walls with Emphasis on Thickness of Infill Plate and Concrete Cover
  Morteza Rastakhiz Ahmad Maleki
  Since the application of composite shear wall is increasing rapidly throughout the world, it is necessary to study its behavior. General interest of engineers in using this unique system due to its application and behavior indicates the need for better understanding of More

  Since the application of composite shear wall is increasing rapidly throughout the world, it is necessary to study its behavior. General interest of engineers in using this unique system due to its application and behavior indicates the need for better understanding of this system. In this paper, by modeling composite shear walls and using Abaqus software and its verification, the results have been used for modeling composite shear wall with emphasis on the impact of number and diameter of bolts under cyclic loading. Solid and shell cements are used for modeling concrete and steel elements respectively. The results of the numerical study shows that 3×3 and 3×2.5 configuration with diameter of 22.2 millimeters of bolts are the best sizes. Manuscript profile