Types of Dampers and their Seismic Performance During an Earthquake. providing damping. So, they were entitled as Added Damping And Stiffness ( ADAS). Result shows shear force in some floors of frames including ADAS damper reduces in comparison to the frames just only with braces. By increasing number of. PARAMETRIC STUDY OF ADAS DAMPERS USING FINITE ELEMENT ANALYSIS Mehdi Eftekhari Lecturer of Civil Engineering Department, Islamic Azad.

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And session vertical stiffness can increase significantly, while they have no effect on session horizontal stiffness which are controlled by low shear modulus elastomer. For bridges designing because of the movement limitation, the effect of increasing alternative period is low in the most projects, but the damping effect in bridges is higher than construction projects. Among the advantages of using dampers we can infer to high energy absorbance, easy to install and replace them as well as coordination to other structure members.

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ADAS Stiffness formulation [9] The stiffness matrix of an elastic nonprismatic element, such as the plates that compose the ADAS device, can be defined using famper flexibility method.

PVD damper acts effectively on low displacements. When the structure response is used as an input, the system us called closed-loop. They can easily be integrated in structures, and they show stable behavior in earthquakes and no environmental temperature, humidity, etc. ADAS elements, as a metallic damper, can be designed to be installed in both new and existing buildings.

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In seismic isolation systems, use of energy dissipation systems, allocated a special place to their selves. And by creating frequency dependent to hysteresis, it increases damping in first structure.

In general, seismic isolation design lead to reduce the structures responses reduction which are in earthquake conditions Ryan et al. As a result, passive systems can be effective only for violation cases that are designed or adapted, accurately Jangid, Using Pall friction dampers[12].

Types of Dampers and their Seismic Performance During an Earthquake

This element is based on Timoshenko beam theory and Shear deformation effects are included. In other word, seismic isolation increases structure vibration period and bridge and distances it from periods containing earthquake main energies. And they have been used as the best dampers extensively in last 30 years. For example, one 1MN PVd damper can acts effectively for 0.

And it is called open-loop system. Copy the following to cite this article: Also, we can reduce replacement caused by earthquake. These dampers are often created by some parallel steel plates.


In a building, due to reducing the energy forces applied to topside and to reduce stress, isolators are installed in structural elements. Using viscous dampers in stern opericardial braces Click here to View figure.

Thus, destruction and damaging in particular and few concentrated points will be exist and it will be possible to replace these parts after the earthquake.

The element has six degrees of freedom at each node: This system includes movable mass which is set to the spring and it is added to damping components. These results indicate that, by increasing ADAS stiffness, ductility of the frame does not change significantly, but frame force level increases. And they use HDRB only for tanks.


These stiffness and damping increasing can be used at high strains to system production. Using Pall friction damper in retrofit[12] Click here to View figure Metallic Dampers submission In this damper, transferred energy to the structure is spent to submission and non-linear behavior in used element in damper.

Semi active control components dose not add mechanical additional energy to structure system which includes structural and stimulus controlso the stability of input and output connections are guaranteed.

X-shaped metal dampers have a significant performance. This linear equation is as follow: Lead has a high initial shear stiffness and low shear flow and they have full elasto plastic behavior and non-fatigue appropriate characteristics in plastic cycle. The advantages of PVD damper include Hwang et al.

In these dampers, metal inelastic deformation is used such as for formability metals such as steel and lead for energy dissipation. Damping Effect on Structural Response Damping increasing reduces structural dam;er acceleration and displacement damping effect at low frequency close to zero have no effect on spectrum amount and at high frequency, it has low effect on response acceleration.