چكيده لاتين
Bending frames are considered one of the most widely used structural systems in reinforced concrete buildings. Strengthening in reinforced concrete structures can be implemented with various goals and methods. Adding steel braces increases the stiffness of the structure, but significantly reduces the ductility parameter of the structure. In recent years, the use of dampers has attracted researchersʹ attention as a suitable solution to compensate for the low ductility weakness of braced frames. When concrete structures are subjected to earthquakes, they are prone to cracking and a reduction in stiffness and strength. Therefore, using dampers in constructed structures can enhance structural behavior. A yielding damper is a type of passive damper made from metal or alloy materials that yield easily. This damper dissipates energy through its plastic deformation, thereby reducing damage to the primary structural elements. Given that the main objective of this research is to numerically and experimentally investigate the performance of a multi-twisted tubular yielding damper in a concrete frame, we have examined the impact of the damper on the seismic behavior of a concrete frame sample. For this purpose, a concrete frame sample was analyzed in two states: with and without the damper, both numerically (using Abaqus software) and experimentally (in the Structural Laboratory at Isfahan University). The laboratory responses studied to evaluate the impact of the damper on the behavior of the concrete frame include force-displacement curves, load-bearing capacity responses, energy dissipation capacity, and determination of seismic parameters. Additionally, this research further investigates the numerical impact of the number of yielding damper shafts on the behavior of the concrete frame. In this stage, we will examine the effect of the number of twisting shafts in the damper (2, 4, and 6 twisting bars) on the capacity curve and seismic parameters of the concrete frame. The laboratory results obtained from this study indicated that by incorporating a twisting yielding damper into the concrete frame, there was a 71% increase in load-bearing capacity and a 61% increase in energy absorption in the concrete frame. Other results from this study showed that the difference between the results obtained from numerical and experimental studies regarding load-bearing capacity parameters in the concrete frame samples with and without dampers was 2% and 5.8%, respectively. Furthermore, the numerical results of this study demonstrated that by changing the number of twisting shafts in the twisting yielding damper, there was an increase in load-bearing capacity and improvement in seismic parameters in the concrete frame. Specifically, this increasing trend with changing from 2 bars to 4 and 6 bars resulted in load-bearing capacity parameters in the frame being increased by 32%, 67%, and 100%, respectively.
