Optimization of Placing Viscous Dampers on 3D RC Frame Subjected to Seismic Loading

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 09 Issue: 03 | Mar 2022 www.irjet.net p-ISSN: 2395-0072
© 2022, IRJET | Impact Factor value: 7.529 | ISO 9001:2008 Certified Journal | Page 1657
Optimization of Placing Viscous Dampers on 3D RC Frame Subjected to
Seismic Loading
Sumanth M1, S. Bhavanishankar2
1PG Student, Dept. of Civil Engineering, University Visvesvaraya College of Engineering, Bengaluru, India
2Associate Professor, Dept. of Civil Engineering, University Visvesvaraya College of Engineering, Bengaluru, India
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Abstract - Earthquakes are one the world's most deadly
natural hazards. Large earthquakes often strike without
warning, leading to catastrophic effects. The National
Earthquake Information Centre (NEIC) archivesanaverage of
20,000 earthquakes every year (approximately 55/day)
around the world.
RC frame structures being most common, on seismic
loading will have large impact to its elements. Since, there are
fundamentally two ways to improve the seismic performance
of these structures. One method is to improve the deformation
capacity of structural memberslikebeams, columnsetc., which
is not always possible in practical situations. Another method
is to add retrofitting techniques like dampers or baseisolators
to increase the seismic performance of the structures.
Adding dampers to the structures, in order to reduce
seismic responses is not only found effective but also
economical in some of the constructions. Hence, in this
dissertation work the efficiency of diagonal and chevron type
viscous damper on 3D-RC frame is assessed based on
placement of the dampers at various locations. Then response
spectrum analysis is carried out here to study the dynamic
behaviour of the structure. It is concluded that the base shear
is reduced when placed at corners of bottom half storey. It is
also observed that it is lesser when placed at center columns
than at alternating one and is vice versa for the latter one.
Key Words: modal analysis, equivalent static analysis,
response spectrum, dampers, etabs
1. INTRODUCTION
In recent years, earthquake-resistant design andretrofitting
of structures with energy absorption systems have received
a lot of attention. Viscoelastic (VE) dampers have proved to
be capable of delivering significant additional dampening to
structures in order to dissipate seismic energy.
Comprehensive experimental and analytical researchonthe
use of viscoelastic dampers have demonstrated that these
dampers are particularly successful inminimisingstructural
vibration at all environmental temperaturesduringmild and
large earthquake ground motions. With the use of VE
dampers, the ductility demand of structures can be greatly
lowered. Many important developments in seismic codes
have been discovered in the recent few years. The majority
of the changes in the seismic design field arise from a
growing awareness of actual poor structural performance in
earthquakes.
Viscous dampers are a type of passive energy dissipation
device that is used to increase the effective stiffness of new
and existing structures. They're made of a tough material,
and energy is transferred by the piston and absorbed or
dissipated by the silicone-based fluid that flowsbetween the
piston and cylinder assembly.
“Three methods are commonly used to classify structural
control systems. Active energy dissipation, semi-active
energy dissipation, and passive energy dissipation are the
three types of structural control systems. Devices that are
utilised to dissipate the seismic effect are known as passive
energy systems. The fundamental purposeofpassivedevices
is to absorb a portion of seismic energy (input energy),
reduce earthquake energy or force on structural elements,
and reduce the proportion of structural damage. In contrast
to semi-active or active systems, passive control systems do
not require external power. The active control system is
tunable and requires some external power to operate. The
sensor attached to the structure will be used by the active
control system.”[1]
1.1 Objectives of Present Study
a. Performance analysis of 3D-RC bare frame under seismic
loading.
b. Relative comparison between different configurations of
models based on location and number of dampers.
c. Evaluation of optimised configurations of the models.
d. Concluding the variation in response of various
configurations
2. METHODOLOGY
Comprehensive literature review is carried out on the
seismic response of 3D RC frames with viscous damping
3D RC frames with G+9 stories and with different
configurational the location of viscous dampers is
considered.
FE analysis involving Modal, Equivalent Static andResponse
Spectrum analyses are considered. The results obtained are
time period, mode shape, displacement, storey drift, base
shear and acceleration. All the results are tabulated,
discussed and conclusions are drawn.

2.1 DESIGN DATA:
Model G+9 with each storey height 3m is considered. The
model has 5 bays in both the horizontal plane each of 4m
width. Thus, the total plan area will be 400 sq. meters.
Table -1: Modelling details
Type of structure Special moment resisting RC
Frame
Grade of concrete M 25 (fck=25N/mm^2)
Grade of reinforcement Fe 500(fy=500 N/mm^2)
Height of building 30m, G+9
Each floor height 3
Number of stories G+8
Column size 600X600mm
Beam size 300*450mm
Slab thickness 150mm
Density of concrete 25KN/m^3
Live Load on roof 2.5 kN/m²
Live Load on Floor 2.5 kN/m²
Floor finish 1 kN/m²
Zone 2, 5
Response reduction factor 5
The two configurations of FluidViscousDampers(FVD)with
data that can be used for modelling in ETABS 2019.
1. Fluid viscous dampers & lock-up device’s clevis - clevis
configuration.
2. Fluid viscous dampers & lock-up device’s cheveron type
configuration.
Fig -1: Fluid viscous dampers
Table -2: Details of FLUID Viscous damper
Damper
notation
Mass
(Kg)
Coefficient
(KN-s/m)
Expone
nt
Stiffness
(KN/m)
FVD 44 300 0.3 25000
DESCRIPTION OF THE MODELS:
The studies are concerned to IO different configurations of
G+9 storey building under seismic zone II and V.
The models considered in this dissertation work are
tabulated in table below
Fig -2: RC Bare Frame Model
2.2 LOAD COMBINATIONS:
Given design load combinations forRCframedstructure
in ETABS are.
 DL+LL+FF
 DL+LL+FF+EQ (for static analysis)
 DL+LL+FF+RS (for response spectrum analysis)
The comparison has been made between the structure
without damper and structures with dampers. A G+9
storey structure with 10 different configurations based
on the placement of dampers are considered
M – Middle column, T – Even column, S – Single damper,
I – Inverted double damper, FC - Column, C- Corners

2.3 RESULTS AND DISCUSSIONS
The important parameters under consideration are
listed below.
 Fundamental time period
 Base reaction
 Displacements
 Acceleration
 Storey drift
2.3.1 FUNDAMENTAL TIME PERIOD
Modal analysis characterizes the seismic properties of
an elastic structure by identifying its mode of vibration.
The response of the structure is different at each of the
different natural frequencies.
Chart -1: Fundamental time period.
Time period of the bare frame structure is found; reduced
when dampers are added to the structure.
The time period obtained from the modal analysisdoesnot
match with time period from codal formulae therefore
provisions have to made in the code for the better results.
2.3.2 BASE SHEAR
The building with more seismic weight will be having high
base shear and low time period.
Chart -2: Base Shear
m
od
el
Details NOMENC
ULATUR
E
1 RC bare frame BF
2 RC bare frame, dampers in middle
column, single all storeys
BMFCS
column, double all storeys
BMFCI
column, single bottomhalfstoreys
BBHMS
column, double bottom half
storeys
BBHMI
6 RC bare frame, dampers at even
column, single all storeys
BTAS
7 Rs bare frame, dampers at even
column, double bottom half
storeys
BTBHI
column, single top half storeys
BMTHS
column, double top half storeys
BMTHI
10 RC bare frame, dampers at
corners, single in all storeys
BACS

Dampers when installed at the bottom half of the structure,
shear force is found to be effectively shared by the dampers
within the structure.
2.3.3 MAXIMUM DISPLACEMENT
Displacement of structure is referredtolateral displacement
at the top of frame. Due to inertia caused by lateral force the
displacement is referred as lateral displacement.
Displacement will be minimum at the base and maximum at
the top of frame. Displacement of the structure increases
with increase in height of the structure.
Chart -3: Displacement curve of G+9 storey building
Below figure shows the maximum displacement graph of all
the models under zone V
Chart -4: Maximum Displacement
2.3.4 ACCELERATION:
In order to study the dynamic behaviour of the
structure, acceleration is one of the important factors
under consideration.
Due to the Maxwell modelling of dampers, the stiffness
of the structure is increased. Thus, frequency of the
structure increases. As the frequency increases the
fundamental time period decreases leading to an
increase in the acceleration.
It is observed even in the models under consideration
that the acceleration of the structures with dampers is
higher than the structures without dampers.

Chart -5: Maximum Acceleration
2.3.5 STOREY DRIFTS:
According to IS 1893(Part 1):2016 clause7.11.1, the
storey drift is the displacement of one level relative to
the other level above or below. Chart 6 shows storey
drift graph of G+9 storey building. And all the values are
tabulated.
Chart -6: Drifts curves of G+9 storey building
The storey drift is appreciably reduced in BACS (bare frame
dampers at the entire storey height single) configuration.
3. CONCLUSIONS
The seismic behaviour ofthe reinforcedconcretestructureis
judged by analysingparameterssuchasdisplacement,storey
drift, acceleration, base shear and fundamental time period.
All the results are well within permissible limits. The
following conclusions can be made based on the analysis
carried out.
1. Time period of the bare frame structure is found to be
reduced when dampers are added to the structure. Sincethe
time period determined by modal analysis differs from the
time period determined by codal formulae, modifications
must be included in the code for better results.
2. Structures where the dampers are at the cornerstorey full
(BACS) have shown significant reduction in thevalueoftime
period. This Model (BACS) has shown about 45.25%
reduction in the value of time period.
3. The base shear of the bare frame structure is found to be
reduced when the structure is stiffened at the base and or at
the bottom half of the structure.
4. Base shear of two models (BMTHI and BTHS) where the
dampers are placed at the top half of the structure is not
effective in the reduction of value since mass is significant at
the top.
5. In comparison between BTAS and BACS, the base shear
value of BACS (dampers at All corner) is quite lesser than
BTAS (dampers at the even column, entire storey height)
though it has same number of dampers.
6. In terms of placing and positioning, Base shear for single
dampers in middle column BMFCS is grater when compared
to dampers placed at even column BTAS.
7. Base shear for doubledampersinmiddlecolumnBBHMIis
greater when compare to dampers placed at even column
BTBHI.
8. It is concluded that base shear at corners bottom half is
least but as for middle column it is less than placed at even
column for single dampers and vice versa for double
dampers.
9. In case of bare frame structure there is about 19.4%
reductions in the displacement response when dampers are
installed at all the floors in the corner for G+9 storey
building.
10. BACS model is stiffer when compared to other
configurations hence they show higheraccelerationvalue by
126.53% when compared to bare frame model.

REFERENCES
[1] Study on the effect of viscous damper for RCC frame
structure Puneeth Sajjan1 , Praveen Biradar2,Febraury
2018.
[2] D. I. NARKHEDE& R. SINHA. 'Shock Vibration Control of
Structures using Fluid Viscous Dampers'. Indian
Institute of TechnologyBombay,Mumbai-400076,India.
2012M. Young, The Technical Writer’s Handbook. Mill
Valley, CA: University Science, 1989.
[3] E-Tabs (2015), Integrated software for structural
analysis and design. Version 15.0.0. Berkeley
(California). Computers & Structures, Inc.; 2007.
[4] FU Y, KASAI K. ‘Comparativestudyofframesusingvisco-
elastic and viscous dampers. J Struct Eng 1998.
[5] GARY C HART. KEVIN WONG. Structural dynamics for
structural engineers.
[6] GLORIA TERENZI 'Dynamics of SDOF systems withnon-
linear viscous damping'. ASCE journal of engineering
mechanics.
[7] GLUCK N, REINHORN AM, GLUCK J, LEVY R. ‘Design of
supplemental dampers for control ofstructures’. JStruct
Eng 1996.
[8] JIANXING CHEN, LIANJIN BAO. ‘Energy dissipation
design with viscous dampers in high-rise buildings’East
China Architectural Design & Research Institute,
Shanghai, China 2012.

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