Today, the use of energy-dissipating system such as Yielding metal damper in structures can improve the seismic performance of structures. One of the characteristics of metal Yielding dampers is the ability to dissipate high energy and increase the ductility of the structural system, which can improve the ductility and energy absorption characteristics of the metal frame equipped with braces and prevent the brace from buckling during an earthquake. The purpose of this research is introduce a new form of Yielding dampers called honeycomb Yielding damper (HYD) with different dimensions and thickness along with evaluating and comparing the force-displacement diagrams and investigating the seismic parameters of this type of Yielding damper. All modeling and validation of numerical samples were done by Ansys software. Non-linear analysis method is used in this research. The hysteresis curves are obtained under in-plane cyclic loads. The mechanical parameters such as ductility ratio, initial hardness, effective hardness and damping coefficient can be determin. The results of this research showed that the effective stiffness increases by increasing the length and thickness of the sample. The ductility ratio decreases by increasing the height of the sample. the effective stiffness decreases by increasing the height of the sample. The ductility ratio increases by increasing the height of the sample. Also, the effective damping coefficient decreases with the increase in the height of the samples, the effective damping coefficient increases with the increase in length and thickness of the samples.

Connections play a crucial role in structures, including steel structures, and have a significant impact on the seismic behavior of the structure. One particular type of connection commonly used in steel structures is the Reduced Beam Section (RBS). This connection reduces the moment strength of the beam near the column, which in turn results in less moment being transferred to the column at the final moment. The study involved 30 numerical analyses conducted using ABAQUS to examine two cases. The first case involved investigating a connection with a beam that had a hole in the flange area. The variables examined included the area of the flange holes and the axial force of the column. In the second case, a yield ring was utilized in the flange area of the beam. The radius of the yield ring was considered as a variable insix different cases. Equations for calculating the maximum strength moment and analyzing the linear region of a beam were presented in the study. The Yielding damper must yield earlier than other members, and an equation was provided to ensure that it does. Finally, the cyclic behavior of the two models was also compared. Numerical analysis revealed that if the area of the flange holes is half that of the beam flanges, the beam's strength does not significantly decrease withincreasing axial force. The elastic stiffness and ductility of the SRD-equipped connection were higher than the RBS model, with the SRD model achieving 1.8 and 2.6 times greater ductility and elastic stiffness, respectively, in the most optimal state.

The concrete structures exposed to the earthquake have the potential of cracking and reduction in stiffness and strength. Because of their low deformability, there would be some cracking and plastic hinging in the moment-resisting frame. The utilization of dampers is a solution to improve the behavior of the constructed structures. dampers play a crucial role in improving structural performance level and bearing capacity. In the present study, 9 concrete frames were tested, and steel yield dampers have been used for the seismic rehabilitation of the concrete moment-resisting frames. The yield dampers elements are ADAS dampers (Added Damping and Stiffness) connected to the concrete frame using steel braces. The concentric-type steel braces connect the dampers and concrete beams. Furthermore, to investigate the influence of the braces on the structure’, s strength and behavior three concentrated braces have been installed in the structure. The structure in which ADAS dampers was employed demonstrated more strength and less recorded damages than the simple moment-resisting frame. In the present study, the effect of braces and dampers have been investigated in the behavior of the structure, cracking, and strength. The strength of the frames was increased by 48% and 21% by employing steel braces and yield dampers in the concrete frames, respectively, comparing the control frame.

Having a long history of seismicity and experienced destructive and deadliest earthquakes make Iran one of the vulnerable countries against earthquakes. Based on the seismic hazard zoning map presented in the Iranian seismic code (2800 provisions), more than 90% of Iranian cities are located in areas with high or very high seismic hazard zones. On the other hand expansion of urbanization in recent decades almost comprises reinforced concrete (RC) buildings. Many of these RC structures constructed in accordance with codes that did not mandate adequate detailing and reinforcement for seismic protection, may have already suffered damage since their erection, due to insufficient maintenance, earthquake activity, or other natural hazards. Therefore providing appropriate solutions for the rehabilitation of such structures has always been considered essential. Metallic energy dissipators have been grown experimentally and theoretically almost for steel structures. U-shaped metallic-Yielding damper as one of the most well-known metallic energy dissipators has also developed as a lateral-load resisting system for strengthening existing steel frames. Experimental and theoretical results showed that U-shaped metallic dampers can operate with large displacements in the inelastic range and dissipate energy through the plastic deformation of the steel. The purpose of this study is to take potential advantages of this system to strengthen deficient RC structures. To the best of the authors’ knowledge, this issue has rarely been considered, most of which are limited to small experimental studies. Therefore, it can be useful to study this issue numerically at the real size structural level. In this regard, three RC intermediate moment frames in 4, 6, and 8 stories and irregular in elevation are considered. Irregularity is considered by a setback in elevation of the frames as a special type of irregularity with considerable effect on seismic performance. Frames were first designed deficiently by SAP2000 software according to the provisions of the Iranian national building code and Iranian seismic code for the intermediate reinforced concrete moment-resisting frames. Then the frames strengthen by adding U-shaped metallic-Yielding dampers together with inverted V-braces. The nonlinear dynamic time-history analysis is performed on all frames subjected to three far source input motions utilizing PERFORM 3D software. Nonlinear specifications of beams and columns are considered by assigning plastic hinges to them in addition to defining nonlinearity for the dampers. The results of roof displacement, base shear, inter-story drifts, and performance of frames at the life safety structural performance level are monitored for both cases with and without dampers. The use of U-shaped metallic dampers has always reduced significantly the maximum lateral displacement of the buildings. On average, under the three records of Imperial Valley, Manjil, and Tabas, the reduction is obtained as 32, 33, and 22 for 4, 6, and 8 story frames, respectively. Such a significant reduction is also visible in the inter-story drifts.  . No major effect on the maximum base shear force is observed and even in some cases, it is increased up to 10%. Failure of frames reduced by transferring nonlinearity of elements to the dampers and seismic performance assessment indicates that dampers strengthen frames to almost satisfy the requirements of the life safety level.

Concentric bracing systems are a popular solution for strengthening moment frames due to their high lateral stiffness, ease of installation, and low cost. However, buckling in compression members can result in sudden loss of strength and less deformability. Researchers have suggested using steel slit dampers to increase deformability and energy dissipation in this system by directing damage away from bracing members. In this study, 265 finite element models were analyzed in ABAQUS software based on previous experimental investigations and the installation configuration of the combined elliptical slit elements with Chevron bracing system in a moment frame. The effects of varying each geometric parameter of the element, including thickness, width, height, and number of slits, as well as the minor diameter of the elliptical slit, on the behavioral characteristics have been investigated in a three-dimensional parametric space. These characteristics are such as elastic stiffness, ductility, force capacity, and cyclic energy dissipation. Finally, and based on conducted numerical analysis, suitable ranges for each geometric parameter have been proposed to facilitate optimal design of the element.

Over years, the energy absorption process against different kinds of loading has always been one the most important issues in the engineering science. To address this, many kinds of dampers such as viscoelastic, friction, Yielding, mass, and liquid dampers have been invented. Among all these dampers, steel Yielding dampers are one of the most economic, available, suitable, and best choices for the long return period of seismic cyclic loading on structures. However, it seems that there are not sufficient studies on these dampers to convince the designers to use them widely. This research tries to show the effects of geometrical parameters on the energy absorption and cyclic behavior on a specific simple trapezoidal steel Yielding damper using the finite element method, then the effect of using a new steel damper on base shear and roof acceleration responses of a three story building studied by nonlinear time history analysis. According to the results, there are some effective and less effective parameters whose variation such as geometrical parameters can seriously change the total energy absorption level and improve the damper hysteresis loops as well as ductility under specific cyclic loading and showed that using new steel damper will results the significant decreasing in base shear and roof acceleration of the building.

Reinforcement of structures with concrete moment frame system by submitting metal damper with optimal cross section has been done in the present study. For this purpose, the metal damper that is delivered after calibration and comparison of the results with a similar experimental sample is simulated in ABAQUS finite element software and the number of blades is determined to have the best performance. Loading was performed by displacement control method on the sample. To investigate the effect of damping on the behavior of the structure, the structural system with the proposed damper was compared with three types of bearing systems of different structures of concrete flexural frame, concrete shear wall and bracing with different number of floors 8, 14 and 20. In this study, 4 groups of concrete structures were studied and compared in terms of lateral bearing system, including medium concrete moment frame with behavior coefficient (R = 5), medium concrete moment frame with shear wall with medium ductility, concrete moment frame with Medium ductility with EBF steel brace and Medium ductility concrete flexural frame with EBF steel brace Equipped with Yielding metal damper. The studied structures have building frames with dimensions of 25 x 25 meters, which are modeled on 8th, 14th and 20th floors. Each dimension of the structure in the plan has 5 openings with lengths of meters. The height of each floor is 3 meters. In modeling structures with dampers, four types of dampers modeled with 4, 6, 8 and 10 flowing plates in the damper have been used. By comparing them, it has been determined that the damping with 10 flowing plates has better performance and the results of that structure in Comparison with other systems was used. In 8-story models, the maximum final displacement in the brace was 17% higher than in the damper. The maximum final displacement in the shear wall was 36% higher than that of the damper. The results of maximum final displacement in 20-storey structures showed that of the 4 types of load-bearing systems, the behavior of concrete shear wall and damper has better performance than other systems. The maximum final displacement in the shear wall was 36% higher than that of the damper. The 8-story structure with dampers not only withstood the highest shear but also had the best performance compared to other systems. Structures such as the system with restraint, shear wall and moment frame had 26, 7. 7 and 62%, respectively. As a general conclusion from the results of the present study, it seems that in structures with a low number of floors, the use of the system with the proposed damper is more appropriate and in medium structures, the shear wall system has a better performance.

A review of the damages caused by previous earthquakes shows that a significant number of the structures constructed in the country are neither earthquake-resistant nor have enough strength. Consequently, reliable, fast, and easy retrofitting methods are needed to improve these structures to withstand lateral forces. In the present study, 9 concrete frames were tested, and Yielding steel dampers have been used for the seismic rehabilitation of the concrete momentresisting frames. TADAS (Triangular-plate Added Damping and Stiffness) dampers are attached to the concrete frame using steel braces. The dampers and concrete beams are connected with concentric steel braces. Moreover, three concentric braces have been installed to investigate the influence of the braces on the strength and behavior of the structure. Compared to the momentresisting frame, the structure that used TADAS dampers exhibited greater strength and recorded fewer damages. Cyclic displacement loading was applied to these frames, and their characteristics, including strength and crack, were investigated. In comparison with the control frame, the steel braces and yield dampers increased the structural strength of the concrete frames by 48% and 28%, respectively.

Use of passive control systems causes reduction in seismic demand and prevents damage to the main components of the structure. Yielding dampers are among the common tools used for dissipation of earthquake energy entering the structure. The main goal of the present research is introduction of a novel pseudo elliptical Yielding damper for improvement of the seismic performance of the existing steel structures. Considering the impact of geometric parameters of the pseudo elliptical damper on its stiffness and strength, a precise numerical study was performed on the ratio of diameter to thickness and other dimensions of the damper in this research.  For evaluating the impact of proposed damper on the seismic performance of existing steel buildings, use was made of three benchmark structures with 3, 9 and 12 stories which were retrofitted by this type of dampers. Also, the nonlinear time history analysis has been performed using the near field and far filed accelerometers to evaluate the analyses results at different seismic states. The results of numerical analyses indicated the good performance of propose pseudo elliptical Yielding damper in terms of dissipating the earthquake energy entering the structure and reduction in the seismic responses of retrofitted benchmark buildings by this type of dampers. It was found that on average, the maximum inter-story drift in the 3, 9 and 20 story benchmark buildings were reduced by 66, 69 and 67%, respectively.

In this paper, the hybrid friction-Yielding damper in the center of X-braced steel frame for dissipating seismic energy and its design methodology are introduced. Due to their relative simplicity and easy application with no need for any special material or technology, this high performance system have gained more attention compared to other means of energy dissipation devises. The advantage of failure localization at circular damper cause this system can be used for rehabilitation of existing building whose slender braces designed based on tension forces only. Possibility of Prompt installation of new ones after strong earthquake is another advantage of this simple system.