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ABSTRACT

Conventional
methods of seismic reintegration with concrete shear walls or rigid steel
bracing are considered expensive and tedious. The schedule and tight budget
meant that these conventional options are not feasible. The principle of
friction brake is most widely adopted available method to extract kinetic
energy from a moving body. It is the most reliable, effective and economical
mean to dissipate energy. This principle of friction brake have inspired the
development of friction dampers. Similar to automobiles, the motion of
vibrating building can be slowed down by dissipating energy in friction.
Several types of friction dampers have been developed. For frame buildings,
these are available for tension cross bracing, single diagonal bracing, chevron
bracing, and friction connectors at expansion joints to avoid pounding. The
paper gives the study of different literature investigation taken on friction
damper.

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I. INTRODUCTION

Now-a-days,
structural control is an advanced technology in the field of engineering to equip
energy dissipation devices or control systems into structures to reduce
excessive structural vibration, enhance human comfort and prevent catastrophic
structural failure due to strong winds and earthquakes. Structural control
technology can also be used for retrofitting of historical structures
especially against earthquakes. The approach to vibration control of structures
is with vibration damping that is added to a structure either passively or
actively. This damping dissipates some of the vibration energy of a structure
by either transforming it to heat or transferring it directly to a connected
structure. By utilizing viscoelastic material as well as dashpots, and
appending the structures with control devices are the most common ways of
adding damping treatment to structures. Effective damping can result by
properly treating the structure, which is not damped adequately with
viscoelastic materials. In addition, viscous dampers, tuned-mass dampers,
friction dampers, dynamic absorbers, shunted piezoceramics dampers, and
magnetic dampers are other mechanisms that are used for passive vibration
control.

FRICTION
DAMPER

For centuries, mechanical engineers have successfully
used the concept of the friction brake to control the motion of machinery and
automobiles. This concept is widely used to extract kinetic energy from a
moving body as it is the most effective, reliable and economical mean to
dissipate energy. The development of friction-damping devices was pioneered in
the late seventies (Pall 1979, Pall 1981). Friction dampers suitable for
different types of construction have been developed for 1) Concrete shear walls,
both precast and cast-in-place (Pall 1980, Pall 198l); 2) Braced steel/concrete
frames (Pall 1982); 3) Low-rise buildings (Pall 1981); and 4) Clad-frame
construction (Pall 1989). Patented Pall friction-dampers are available for: tension
cross bracing; single diagonal bracing; chevron bracing; cladding connections;
and friction base isolators. These friction dampers meet a high standard of
quality control. Every damper is load tested to ensure proper slip load before
it is shipped to site. Pall friction-dampers are simple and fool-proof in
construction and inexpensive in cost. Basically, these consist of series of
steel plates which are specially treated to develop most reliable friction.
These plates are clamped together with high strength steel bolts and allowed to
slip at a predetermined load. Cyclic dynamic laboratory tests have been
conducted on specimen friction-damping devices (Pall 1980, Filiatrault 1986).
Their performance is reliable, repeatable and possess large rectangular
hysteresis loops with negligible fade over several cycles of reversals that can
be encountered in successive earthquakes.

 

Fig. Concordia’s
Library Building Connected with Pall Friction Damper

 

 

II.
LITERATURE REVIEW

Imad H. Mualla and Borislav Belev (2002) investigated
the performance of a friction damper installed in a single storey steel frame
subjected to seismic loading.  Numerical
simulations based on non-linear time history analysis were used to evaluate the
seismic behavior of steel frames with inserted FDD. The governing parameters
were identified and their influence was traced and summarized along with
implications for practical design.
The results showed that the friction damper can be used improve the dynamic
response of innovative structures as well as the existing building compared to
the conventional design.

 

W. L. He et. al. (2003) demonstrated semi active
friction dampers (SAFD) to be more effective than passive friction dampers in
reducing the structural response due to earthquakes. The motion of friction
dampers, either passive or semi active, involves sticking and slipping phases. Two
buildings, a six-story base-isolated building and a three-story fixed base
building model, have been used to demonstrate the performance of the proposed
control strategies using different far-field and near-field earthquakes.
Further, the performances of various combinations of passive and semi active
energy dissipation devices have been evaluated and compared. Based on numerical
simulation results, it was demonstrated that the proposed semi active friction
control strategies are very effective.

 

A.V.
Bhaskararao and R.S. Jangid (2004) investigated on seismic responses of two adjacent structures which was modelled as
single degree of freedom (SDOF) structures connected with a friction damper. Friction
dampers connected to two numerical models were also proposed for multi degree
of freedom structures (MDOF) as the process involved was quite cumbersome as
some dampers were required to be vibrated in sliding phase and the rest in
non-sliding phase. They found that the two numerical models were predicting the
dynamic behavior of the two connected SDOF structures accurately. The results
showed that if the slip force of the friction dampers was selected appropriately
the different fundamental frequencies of adjacent structures can effectively
reduce earthquake-induced responses of either structure. They further concluded
that lesser dampers at appropriate locations can significantly reduce the
earthquake response of the combined system rather than connecting the dampers
at all floors.

 

M. D. Symans et. al. (2008) investigated on a summary
of recent developments and current codal practices in the application of
passive energy dissipation systems for seismic protection of structures. The
emphasis is on the application of passive energy dissipation systems within the
framing of building structures. Extensive topics were discussed  which included basic principles of energy
dissipation systems, descriptions of the mechanical behavior and mathematical
modeling of selected passive energy dissipation devices, advantages and disadvantages
of these devices, development of guidelines and design philosophy for analysis
and design of structures employing energy dissipation devices, and design
considerations that were unique to structures with energy dissipation devices.
A selection of recent applications of passive energy dissipation systems was
also presented.

 

Songye Zhu and Yunfeng Zhang (2008) investigated on a
special type of bracing element termed self-centering friction damping brace
(SFDB) for use in seismic-resistant concentrically braced frame (CBF) systems.
The SFDB is a passive energy dissipation device with its core re-centering
component made of stranded super elastic nitinol wires while enhanced energy
dissipation mechanism of the SFDB is achieved through friction. A comparative
study of SFDB frame and buckling restrained braced (BRB) frame was carried out,
which is based on nonlinear dynamic analysis of two prototype CBF buildings, a
three and a six-storey steel frame. The results of the nonlinear time-history
and pushover analysis showed that the SFDB frame can achieve a seismic response
level comparable to that of the BRB frame while having significantly reduced
residual drifts. The SFDB thus has a potential to establish a new type of CBF
system with self-centering capability.

 

You-Lin XU and C.L. Ng
(2008) investigated experimentally on control of
seismic response of a building complex with the use of variable friction
damper. Building complex consisted of a 3-storey podium structure coupled and a
12-storey building. The performance test was conducted under constant or
varying voltage to identify motion-independent characteristics on the
piezo-driven variable friction damper. Two classes of semi active controllers;
local-feedback controller and global-feedback controller, together with a closed-loop
operating scheme was proposed for real-time operation of the damper as per
characterization results. Finally, the building complex was tested in rigid-coupled,
uncoupled, semi active damper-coupled, and passive damper-coupled
configurations. Also the variable friction damper’s performance was examined
for the building complex and results were compared. The results showed that
semi active coupling control was promising for reducing seismic responses of
both buildings.

 

Brian G. Morgen and Yahya C. Kurama (2008) evaluated
seismic response of unbonded post-tensioned precast concrete moment frames that
used friction dampers at selected beam ends. The parameters investigated included
the number of stories, number and strength of the dampers, and amount of
post-tensioning. Nonlinear static and dynamic time history analysis of
prototype structures showed that the dampers provided a considerable amount of
energy dissipation to a frame, while the post-tensioning force provided a
restoring effect resulting in self-centering capability. The seismic design of
the structures to achieve target displacement-based performance objectives was
critically evaluated based on the analysis results. The dynamic analysis
results also indicated that, in comparison with post-tensioned precast concrete
frames, fully emulative structures that used only mild steel reinforcement
through the beam-column joints have undergone smaller peak lateral
displacements; however, they accumulate significant residual displacements at
the end of a ground motion, indicating a larger amount of damage in the
structure. The peak displacement demands for fully post-tensioned frames
without friction dampers are significantly larger than frames with friction
dampers.

 

Usha K and Dr. H. R. Prabhakara (2017) analyzed two
models (i.e. G+3 and G+7) equivalent
static method, response spectrum method and time history method. The modeling
and analysis was done with SAP 2000 v 14 software and the results that were,
seismic parameters such as Time period, Base shear, Lateral displacement and
Inter storey drift were tabulated and then comparative study of structures with
and without Friction dampers has been done. They concluded that lateral
displacements due to earthquake forces were reduced by providing friction
dampers and the storey drift also reduces shear resistance of the building
increases.

 

III. CONCLUSION

The
seismic performance of the frame can be considerably enhanced by the inclusion
of friction damper in the structural system. The dissipation characteristics of
the friction damper are reliable and the devices are not damaged by large
loads. By confining the energy dissipation to the friction damper which are
specifically designed to perform under extreme loading conditions without
sustaining damage, the main structural elements are able to remain elastic. The
device provides a significant increase in the available damping within the
structure and that leads to a direct improvement in performance.

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