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International Journal of Civil Engineering and Technology (IJCIET) Volume 7, Issue 4, July-August 2016, pp. 422–431 Article ID: IJCIET_07_04_037

Available online at http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=4

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

© IAEME Publication

STUDY OF POUNDING MITIGATION TECHNIQUE BY

USE OF ENERGY DISSIPATION DIVICES

Quraishi Izharulhaque

PG Student, Department of Civil Engineering,

Jawaharlal Nehru Engineering College,

BAMU Aurangabad-431001, Maharashtra, India

Sangeeta Shinde

Head of Department, Department of Civil Engineering,

Jawaharlal Nehru Engineering College,

Aurangabad-431001, Maharashtra India

ABSTRACT

In this paper the pounding mitigation techniques using dampers are studied in detail. The

dampers such as viscous damper, viscoelastic damper, friction damper and tunned mass dampers

can be used as a energy dissipation devices, however viscous damper and viscoelastic dampers are

most commonly used. Viscous material is material in which strain developed over a period of time

and material does not go to its original shape after stress is removed. Viscoelastic material is a

material in which total strain developed has two components namely viscous and elastic. In this

case the response of viscous and viscoelastic dampers are studied with respect pounding of

building.

Key words: Seismic Pounding, Time Histories, Viscous Damper, Viscoelastic Damper.

Cite this Article: Quraishi Izharulhaque and Sangeeta Shinde, Study of Pounding Mitigation

Technique by Use of Energy Dissipation Divices. International Journal of Civil Engineering and

Technology, 7(4), 2016, pp.422–431.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=7&IType=4

1. INTRODUCTION

Conventional seismic design attempts to make buildings that do not collapse under strong earthquake

shaking, but may sustain damage to non-structural elements and to some structural members in the

building. This may render the building non-functional after the earthquake, which may be problematic in

some structures, like hospitals, which need to remain functional in the aftermath of the earthquake. Special

techniques are required to design buildings such that they remain practically undamaged even in a severe

earthquake. Buildings with such improved seismic performance usually cost more than normal buildings

do. However, this cost is justified through improved earthquake performance. Two basic technologies are

used to protect buildings from damaging earthquake effects. These are Base Isolation Devices and Seismic

Dampers. The idea behind base isolation is to detach (isolate) the building from the ground in such a way

that earthquake motions are not transmitted up through the building, or at least greatly reduced. Seismic

dampers are special devices introduced in the building to absorb the energy provided by the ground motion

Study of Pounding Mitigation Technique by Use of Energy Dissipation Divices


to the building (much like the way shock absorbers in motor vehicles absorb the impacts due to

undulations of the road).

Controlling seismic damage in buildings and improving their seismic performance is by installing

seismic dampers in place of structural elements, such as diagonal braces. These dampers act like the

hydraulic shock absorbers in cars – much of the sudden jerks are absorbed in the hydraulic fluids and only

little is transmitted above to the chassis of the car. When seismic energy is transmitted through them,

dampers absorb part of it, and thus damp the motion of the building. Dampers were used since 1960s to

protect tall buildings against wind effects. However, it was only since 1990s, that they were used to protect

buildings against earthquake effects. Commonly used types of seismic dampers include viscous dampers

(energy is absorbed by silicone-based fluid passing between piston-cylinder arrangement), friction dampers

(energy is absorbed by surfaces with friction between them rubbing against each other), and yielding

dampers (energy is absorbed by metallic components that yield). In India, friction dampers have been

provided in a 18-storey RC frame structure in Gurgaon.

High rise building structures are prone to seismic pounding. ‘Pounding’ is a phenomenon, in which two

buildings strike due to their lateral movements induced by lateral forces [1]. Earthquake is one of the major

causes for lateral forces on the buildings and an efficient and durable structural design is always required

to prevent pounding. For example, in dense populated cities, the residential apartments and office building

are built in close proximity having a small gap (expansion joint) between them. These buildings are always

exposed to various levels of natural and man-made hazards which may cause pounding. Such buildings are

usually separated by an expansion joint which is insufficient to accommodate the lateral movements of

buildings under earthquakes. Therefore, the safety of these highly congested buildings constitutes a major

concern for the authorities in general and structural engineers in particular [2].

In this paper the pounding mitigation techniques using dampers are studied in detail. The dampers such

as viscous damper, viscoelastic damper, friction damper and tunned mass dampers can be used as a energy

dissipation devices, however viscous damper and viscoelastic dampers are most commonly used. Viscous

material is material in which strain developed over a period of time and material does not go to its original

shape after stress is removed. Viscoelastic material is a material in which total strain developed has two

components namely viscous and elastic. In this case the response of viscous and viscoelastic dampers are

studied with respect pounding of building.

2. METHODOLOGY

Two adjacent buildings are considered to be separated by an expansion gap of 50mm. First building is

G+13 and second building is G+8. To demonstrate that the provided gap is only a expansion gap and not a

seismic gap an equivalent static analysis is performed on the two building separately to calculate the

maximum lateral displacement. The actual seismic gap required as per clause 7.11.3 of IS 1893:2002 is

calculated as 877 mm and hence the seismic pounding occurs in the buildings.

Pounding is purely dynamic in nature and it is very difficult to actually predict the pounding force

which is highly uncertain. The pounding force is dependent on various building properties. To have an

better idea of the pounding force the buildings are then subjected to three earthquake ground motion

characteristics namely El Centro, Uttarkashi and Chamoli earthquake.

The three different building models are considered and subjected to three different ground motion

characteristics. In this study it is presume that the building is existing building and will be retrofitted using

dampers. The stiffness of gap element is kept equal to 20 times stiffer than the lateral storey stiffness of

stiffener building considering the building as a bare frame (Model M1). The main aim of the study is to

recommend the proper dampers which will be effective in reducing seismic pounding of building. The

three different models considered are described below

Quraishi Izharulhaque and Sangeeta Shinde


2.1. Model I (M1)

G+13 and G+8 buildings existing buildings with separation gap of 50mm. The taller building and smaller

building is of bare frame system. This model is considered as bench mark model.

2.2. Model II (M2)

G+13 and G+8 buildings existing buildings with separation gap of 50mm. The viscoelastic dampers are

provided for the building at the specific locations shown in figure 2.

2.3. Model III (M3)

G+13 and G+8 buildings existing buildings with separation gap of 50mm. The viscous dampers are

provided for the building at the specific locations shown in figure 3.

The properties of dampers used in the analysis are shown in table 1 below.

Table 1 Calculated properties of dampers

Sr. No Item

Viscoelastic damper Viscous damper

Taller

Building

(G+13)

Smaller

Building (G+13)

Taller

Building

(G+13)

Smaller

Building

(G+13)

1 Stiffness (KN/m) 25000 25000 105.63 x106 105.63 x10

6

2 Damping(KN-s/m) 94909.9 65434 720 720

3 Damping Exponent 1 1 0.3 0.3

The dampers are provided for selected bays in plan and at every alternate floor. For model M2 and M3

the location of dampers are kept same and only type of the dampers are changed. The location of dampers

in plan and elevation of building is shown in following figures

3. MODELING AND ANALYSIS

The three dimensional mathematical model of the building is prepared by using ETABS analysis package.

The beams and column are modeled by using two nodded beam element. Being a lateral load analysis slab

is modeled using membrane element with 3 DOF at each node. The shear wall is modeled by shell element

with 6 DOF at each node.

The building gap is modeled by using nonlinear link element with GAP properties. The stiffness of

GAP element does not affect the analysis results however it is found from the available literature that the

Gap element should be approximately 20 times stiffer than the lateral storey stiffness of stiffer building..

The viscous and viscoelastic dampers are modeled by using nonlinear link element having property type

dampers. The link elements have six DOF at each node. The viscoelastic dampers are modeled as per

Maxwell model of viscoelasticity. The properties of viscoelastic dampers are calculated from shear storage

modulus and shear loss modulus.

Study of Pounding Mitigation Technique

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Maxwell Model of Viscoelasticity

The force in the device may be expressed by

�� ∆

Keff = Effective stiffness of damper

µ = Velocity

Δ = Displacement

Velocity dependant damping is linear function of velocity that is exponent =1

For viscous dampers since pure damping is desired the stiffness of damper is kept around 10

stiffness of surrounding elements. The stiffness of surrounding element is calculated by using sectional

properties like area, Yong’s modulus and length of member. The prope

provided as per Tayler specifications.

Figure 1

f Pounding Mitigation Technique by Use of Energy Dissipation Divices

http://www.iaeme.com/IJCIET/index.asp 425

Maxwell Model of Viscoelasticity

e force in the device may be expressed by

∆ �

Effective stiffness of damper

= Displacement


since pure damping is desired the stiffness of damper is kept around 10


properties like area, Yong’s modulus and length of member. The properties of viscous damper are

provided as per Tayler specifications.

Figure 1 Typical3D FEM Model of building (M1)

f Energy Dissipation Divices

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since pure damping is desired the stiffness of damper is kept around 102 times the


rties of viscous damper are



Figure 2 Plan showing Location of Dampers (Model M2 and M3)

Figure 3 Elevation showing Location of Dampers (Mode

4. RESULTS AND DISCUSSI

The results obtained from analysis are presented below. It is should be noted that in this case the dampers

are applied to taller building as a retrofitting measure. The pounding of building is largely dependent on

location of dampers the study of damper regarding their locatio

locations of dampers are selected to get optimized results.



Plan showing Location of Dampers (Model M2 and M3)

Elevation showing Location of Dampers (Model M2 and M3)

RESULTS AND DISCUSSION



location of dampers the study of damper regarding their location is out of scope of this paper

locations of dampers are selected to get optimized results.

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Plan showing Location of Dampers (Model M2 and M3)

l M2 and M3)



n is out of scope of this paper however the



Figure 3 Time history of Pounding force at Roof Level (Chamoli)

Figure 4 Time history of Pounding force at Roof Level (Uttarkashi)

Figure 5 Time history of Pounding force at Roof Level



Time history of Pounding force at Roof Level (Chamoli)

ime history of Pounding force at Roof Level (Uttarkashi)

Time history of Pounding force at Roof Level (Elcentro)


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Time history of Pounding force at Roof Level (Chamoli)

ime history of Pounding force at Roof Level (Uttarkashi)

(Elcentro)



No impact at roof level was observed for uttarkashi earthquake when dampers are used, however there

is little increase in impact force for model M2 was observed at roof level. The

all the time histories are shown below

Figure 6

Figure 7




ase in impact force for model M2 was observed at roof level. The

all the time histories are shown below

Figure 6 Storey wise maximum impact force (Uttarkashi)

Figure 7 Storey wise maximum impact force (Chamoli)

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ase in impact force for model M2 was observed at roof level. The story wise impact forces for

mpact force (Uttarkashi)

m impact force (Chamoli)



Figure 8

Considerable reduction in impact forces was observed in model M2 and M3. The model M2

(Viscoelsatic dampers) seems to be more effective than model M

levels are shown below.

Figure 9



Figure 8 Storey wise maximum impact force (Elcentro)


(Viscoelsatic dampers) seems to be more effective than model M3 (Viscous damper). No of impacts at all

Figure 9 Storey wise number of Impacts (Uttarkashi)


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)


3 (Viscous damper). No of impacts at all



Figure 10

Figure 11

As observed from above figure there is no impact for uttarkashi time history in both the models

provided with dampers. (ie M2 and M3), however there was around 17 impact for model M1 for uttarkashi

time history. In chamoli and Elcentro time history the number of impacts was considerably reduced for

model M2 and M3. The number impacts were minimum for model M3 at roof level and model M2 at other

levels. The model M3 is more effective as far as numbers of impacts are concern.

6. CONCLUSION

• Dampers proves to be very effective in reducing the impact force as well as number of impacts. The dampers

can be used as a retrofitting measures to reduce pounding but location of dampers will highly influence the

pounding behavior of buildin

• There is no impact at all levels in uttarkashi earthquake for model M2 and M3.

• The impact force is minimum in model M3 in chamoli earthquake which is around 36% less than model M1.



Figure 10 Storey wise number of Impacts (Chamoli)

Figure 11 Storey wise numbers of Impacts (El Centro)



nd Elcentro time history the number of impacts was considerably reduced for



Dampers proves to be very effective in reducing the impact force as well as number of impacts. The dampers


pounding behavior of building.

There is no impact at all levels in uttarkashi earthquake for model M2 and M3.

The impact force is minimum in model M3 in chamoli earthquake which is around 36% less than model M1.

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nd Elcentro time history the number of impacts was considerably reduced for



Dampers proves to be very effective in reducing the impact force as well as number of impacts. The dampers


There is no impact at all levels in uttarkashi earthquake for model M2 and M3.

The impact force is minimum in model M3 in chamoli earthquake which is around 36% less than model M1.

Study of Pounding Mitigation Technique by Use of Energy Dissipation Divices


• The impact force is minimum for Elcentro earthquake in model M2 which is 33% less compared with model

M1.

• The number of impacts at roof level are found to be minimum in model M3 for all time histories hence

viscous dampers are more effective than viscoelastic damper as far as number of impacts was concerned.

REFRENCES

[1] Abdel, R. and E. Shehata. Seismic Pounding between Adjacent Building Structures. Electronic Journal of

Structural Engineering. 66–74 (2006).

[2] Alireza, M. G., R. Kami, and A. Ebadi. Study of Impact between Adjacent Structures During Earthquake.

Structural Mechanics. 6:106–117 (2002).

[3] S. Khatiwada, N. Chouw and J.W. Butterworth, Development of pounding model for adjacent structures

in Earthquakes. Proceedings of the Ninth Pacific Conference on Earthquake Engineering Building an

Earthquake-Resilient Society 14–16 April, 2011.

[4] Murty, C.V.R, Earthquake Tips Learning and Earthquake Design and Construction. National Information

Center of Earthquake Engineering, IIT Kanpur, India, September, 2005.

[5] A. Bartkowiaka and H. Maciejewskia, Dynamic analysis of frames with viscoelastic dampers: a

comparison of damper models, R. Lewandowski Structural Engineering and Mechanics, Volume 41, No.

1 (2012) 113-137 113)

[6] P. D. Pawar1, Dr. P. B. Murnal, Effect of Seismic Pounding on Adjacent Blocks of Unsymmetrical

Buildings Considering Soil-Structure Interaction. International Journal of Emerging Technology and

Advanced Engineering 4(7), July 2014.

[7] Waseem Khan, Dr. Saleem Akhtar, Aslam Hussain, Non-linear time history analysis of tall structure for

seismic load using damper, International Journal of Scientific and Research Publications, 4(4), April

2014.

[8] Jinkoo KIM and Chang-Yong LEE, Analysis of a non-proportionally damped building structure with

added viscoelastic dampers.

[9] Gang Li and Hongnan Li, Earthquake-resistant design of RC frame with dual functions metallic dampers,

The 14th World Conference on Earthquake Engineering Beijing, China. October 12–17, 2008.

[10] Yukihiro Tokuda and Kenzo Taga, A case of structural design in which viscous dampers are used to

enhance earthquake resisting performance of a building. The 14th World Conference on Earthquake

Engineering Beijing, China. October 12–17, 2008.

[11] Abhijitsinh Parmar, Vidhi Patel, Bhrugu Kotak and Mittal Patel, Seismic Response Control of

Asymmetric Building Using Viscous Damper. International Journal of Civil Engineering and

Technology, 5(12), 2014, pp.267–276.

[12] Rajneesh Kakar, Kanwaljeet Kaur and K. C. Gupta, Viscoelastic Modeling of Aortic Excessive

Enlargement of An Artery. International Journal of Mechanical Engineering and Technology, 4(2),

2013, pp.479–493.

[13] Fabian R. Rojas, James C. Anderson and M.ASCE, Pounding of an 18-Story Building during recorded

earthquakes, American Society of Civil Engineers, 2012.

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