7/30/2019 Energy Dissipation Dampers
1/14
ENERGY DISSIPATION DAMPERS
SUB : EARTHQUAKE RESISTANT ARCHITECTURE
PRESENTATED BY : TANVI GARG (2008UAR133)
7/30/2019 Energy Dissipation Dampers
2/14
INTRODUCTION
ACTIVE ENERGY DISSIPATION DEVICES - Active control systems sense and resist
building motion, either by applying external force or by modifying structural properties of
active elements.
PASSIVE ENERGY DISSIPATION DEVICES - add damping (and sometimes stiffness)to the building. Ideally, energy dissipation devices dampen earthquake excitation of the
structure that would otherwise cause higher levels of response and damage to
components of the building.
CONCEPTUALLY, isolation reduces response of the superstructure by decoupling the
building from the ground. Typical isolation systems reduce forces transmitted to the
superstructure by lengthening the period of the building and adding some amount of
damping.
Among the most important advanced techniques of earthquake resistant design and
construction are: Base Isolation
Sliding systems
Energy damping Devices
7/30/2019 Energy Dissipation Dampers
3/14
BASE ISOLATORS
7/30/2019 Energy Dissipation Dampers
4/14
7/30/2019 Energy Dissipation Dampers
5/14
ENERGY DAMPING DEVICES
DAMPING DEVICES AND BRACING SYSTEMS
Damping devices are usually installed as part of bracing systems, with one end attached to
a column and one end attached to a floor beam. Primarily, this arrangement provides
the column with additional support. Most earthquake ground motion is in a horizontal
direction; so, it is a buildings columns which normally undergo the
most displacement relative to the motion of the ground.
When seismic energy is transmitted through them, dampers absorb part of it, and thus
damp the motion of the building.
7/30/2019 Energy Dissipation Dampers
6/14
ENERGY DAMPING DEVICES - TYPES
Damping devices that have been developed can
be grouped into three broad categories:
Friction Dampers: these utilize frictional forces to
dissipate energy (energy is absorbed by surfaces
with friction between them rubbing against each
other)
Metallic Dampers : utilize the deformation of metal
elements within the damper (energy is absorbed
by metallic components that yield)
Viscoelastic Dampers : utilize the controlled
shearing of solids (energy is absorbed by utilizing
the controlled shearing of solids)
Viscous Dampers: utilized the forced movement of
fluids within the damper (energy is absorbed by
silicone-based fluid passing between piston
cylinder arrangement)
7/30/2019 Energy Dissipation Dampers
7/14
FLUID VISCOUS DAMPER
A fluid viscous damper resembles the common shock absorber such as those found inautomobiles.
The piston transmits energy entering the system to the fluid in the damper, causing it to
move within the damper.
The movement of the fluid within the damper fluid absorbs this kinetic energy by
converting it into heat.
energy dissipation is achieved through the use of a moving piston in a hollow cylinderfilled with a silicone-based fluid compound, which is forced to pass through small orifices
around and through the piston head. Energy is transformed into heat due to friction
7/30/2019 Energy Dissipation Dampers
8/14
7/30/2019 Energy Dissipation Dampers
9/14
METALLIC DAMPERS
In these devices, energy dissipation is based on the ability of metals to undergo numerousinelastic cycles until failing and therefore to absorb significant amounts of energy.
Metallic dampers are usually made from steel.
They are designed to deform so much when the building vibrates during an earthquake that
they cannot return to their original shape.
This permanent deformation is called inelastic deformation, and it uses some of the
earthquake energy which goes into building. It is the stiffness ratio rather than the ductility ratio that has a greater effect on the
performance of the devices under seismic loading.
http://www.ideers.bris.ac.uk/resistant/damping_metallic.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_metallic.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_metallic.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_metallic.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_metallic.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_metallic.html7/30/2019 Energy Dissipation Dampers
10/14
FRICTION DAMPERS
In this case, energy is dissipated by the friction that is generated due to the sliding of twosolid materials against each other.
Friction dampers are designed to have moving parts that will slide over each other during a
strong earthquake. When the parts slide over each other, they create friction which uses
some of the energy from the earthquake that goes into the building.
The damper is made up from a set of steel plates, with slotted holes in them, and they are
bolted together. At high enough forces, the plates can slide over each other creatingfriction. The plates are specially treated to increase the friction between them.
http://www.ideers.bris.ac.uk/resistant/damping_friction.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_friction.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_friction.htmlhttp://www.ideers.bris.ac.uk/resistant/damping_friction.html7/30/2019 Energy Dissipation Dampers
11/14
FRICTION DAMPERS
7/30/2019 Energy Dissipation Dampers
12/14
7/30/2019 Energy Dissipation Dampers
13/14
TUNED MASS DAMPER
Tuned mass dampers (TMD) employmovable weights on some sort of springs.
These are typically employed to reduce
wind sway in very tall, light buildings.
Typically, the dampers are huge concrete
blocks or steel bodies mountedin skyscrapers or other structures, and
moved in opposition to the resonance
frequency oscillations of the structure by
means of springs, fluid or pendulums.
7/30/2019 Energy Dissipation Dampers
14/14
DIFFERENCE
METALLIC DEVICE VISCOUS DEVICE
The metallic device is referred to as
a rate-independent device.
The metallic device is rateindependent since the resisting force
in the device is a function only of the
relative displacement across the
device.
The viscous device is classified as a
rate-dependent device.
The viscous device is ratedependent since the resisting force in
the device is dependent, in part or in
full, on the relative velocity across the
device