Earthquakes have consistently posed significant threats to the construction industry, pro‎mp‎ting ongoing research to find effective mitigation measures. In response to this, dampers, identified as passive control systems, have been introduced to alleviate the impact of earthquakes on structures. These devices aim to reduce the intensity of seismic effects, consequently minimizing the extent of damage incurred. One noteworthy type of damper in this category is the rotational-torsional damper, specifically designed for incorporation into the bracing systems of steel structures, serving as an energy-absorbing damper. The operational mechanism of this damper transforms axial force applied to the structure into torsional force, effectively preventing the transmission of earthquake energy through the utilization of sacrificial components, also known as dissipaters. These dissipaters serve as protective elements for the structure, being replaceable. In the event of an earthquake, they can be substituted with new components. Given the substantial cost associated with integrating dampers into structures, the optimal design of these dampers holds paramount significance. Various analytical and numerical methods have been devised in this realm, and one such approach is the theory of uniform displacement distribution. This method contends that when damage is unevenly distributed in a structure, the full capacity of the structure cannot be effectively harnessed. By adopting relative inter-story displacement as a damage parameter, the method strives to equalize this parameter across all floors of the structure. Following this approach, it becomes imperative to diminish damper capacity in floors well below the allowable limit while augmenting capacity in floors where relative inter-story displacement surpasses the allowable limit. This not only optimizes the utilization of the structure's capacity but also contributes to a reduction in construction costs. This thesis presents an algorithm for the optimal design of a Torsional Hysteretic Damper for Frames (THDF) based on the theory of uniform displacement distribution. Notably, the algorithm achieves an optimal distribution with minimal computational cost for this damper. The study involved the design of structures with 4, 8, and 12 stories, determining their mass and stiffness. Subsequently, 11 earthquake records served as input forces for time history analysis, and their information was extracted. The results demonstrate that the use of the THDF damper in seismic control significantly reduces inter-story displacement. Investigations highlight that an improper distribution leads to a substantial increase in damper capacity and, consequently, installation costs. Utilizing the proposed algorithm for optimal damper design results in an approximate reduction of 41%, 78%, and 75% in damper usage for 4, 8, and 12-story structures, respectively, compared to the uniform distribution case. The thesis concludes by discussing the achieved results and the potential of the proposed algorithm for optimal design.

پيام اسدي

مرتضي مدح خوان , حسين تاجمير رياحي