Page 1 of 5

European Journal of Business &

Social Sciences

Available at https://ejbss.org/

ISSN: 2235-767X

Volume 07 Issue 05

May 2019

Available online:https://ejbss.org/ P a g e | 831

Performance Of Dampers In Reinforced Concrete Building Frames

A. ASHOK BABU

DEPARTMENT OF CIVIL ENGINEERING

PRIST (Deemed to be University), THANJAVUR.

ABSTRACT

Conventionally, the structures are designed to resist dynamic forces through the combination of

strength,deformability and the energy absorption. These structures deformwell beyond elastic

limit in a severe earthquake. The extent of damage the earthquake maycause to the structure may

depend on severity of the earthquake, distance from the epicenterand many other factors. The

damage can be reduced by proper analysis and design of thestructure. To avoid the damage of

the structure due to conventional ductility based design,Structural engineers are working to

figure out different alternative systems that could berobust and can withstand strong motions.

Energy dissipation devices is one of the system thatwork by absorbing or reflecting a portion of

the input energy that would otherwise betransmitted to the structure itself and would damage the

structure. In such situations structuralcontrol techniques are more promising for earthquake

resistant design. The concept of thesetechniques is to absorb the vibration energy of the structure

and hence reduce the stresses inthe structure.

INTRODUCTION

From the past and few present records, the

world has experienced number of destroying

earthquakes, causing in number of increase

the loss of human being due tostructural

collapse and severe damages to structure.

Because of such type of structuraldamages,

during seismic (earthquake) hazards clearly

explains that the buildings / structureslike

residential buildings, public life-line

structures, historical structures and industrial

structures should be designed to seismic

force design and very carefully to overcome

fromthe earthquake hazards. The approach

in structural design using seismic response

controldevice is now widely accepted for

structure and frequently used in civil

engineering field.

Page 2 of 5

European Journal of Business &

Social Sciences

Available at https://ejbss.org/

ISSN: 2235-767X

Volume 07 Issue 05

May 2019

Available online:https://ejbss.org/ P a g e | 832

Serious efforts have been undertaken to

develop the structural control concept into a

workable technology and such devices are

installed in structures.

The structural control system is usually

classified by three methods. The three

classesof structural control system are active

energy dissipation, semi-active and passive

energydissipation. The passive energy

systems are devices which are used to

dissipate the seismiceffect. The main

function of the passive devices is to absorb a

part of earthquake energy i.e.,input energy,

reducing earthquake energy or force on

structural members and to reducing

thepercentage of the damage to the

structures. Comparing to semi-active or

active systems thereis no need of external

power supply to the passive control system.

The active control system iscontrollable and

requires some amount of external supply in

processing. The active control system will

operate on the sensor which is attached to

structure. The semi-active systems arethe

energy dissipating devices which is the

combination of both active and passive

controlsystem. These systems dissipate

major portion of seismic energy and reduce

the forces on theprimary structure, thereby

limiting the structural deformations. The

structural control systemsare classified

under following basic headings as passive,

active and semi-active controlsystems. In the

present study attempt is made as how to

arrive at the final values of viscous

damper properties to be entered in the E-tabs

software.

EXPERIMENTAL INVESTIGATION

In order to define the relationship between

frame response and damper placements for

subsequent experimental verification, a

series of analytical simulations on semi-rigid

frames

with various dampers were carried out using

ANSYS. The parameters considered in the

preliminary designs included the curved

damper length and angle. Table 1 lists the

framedetails considered in the numerical

simulation. These frames were subjected to

push-overloads up to 5% drift ratio. Fig. 2

describes the considered frame stress

distributions. Thefigure shows that critical

stress at the beam-to-column connections

was effectively shifted tothe prescribed

curved dampers, as expected, which justified

Page 3 of 5

European Journal of Business &

Social Sciences

Available at https://ejbss.org/

ISSN: 2235-767X

Volume 07 Issue 05

May 2019

Available online:https://ejbss.org/ P a g e | 833

the design feasibility. Therelationship

between the frame strength, i.e. the capacity

of the system, and the variousdamper

geometries, i.e. length and angles, is shown

in Fig. 3. The figure shows that

framestrength decreases when the damper

angle increases. Further comparison on the

relationshipbetween frame strength and

curved damper eccentricities, revealed

thatthe frame strength was greatly

influenced by the damper eccentricity

magnitude. Therefore, itis essential that the

damper geometries be adequately

determined so that significant

structuralperformance could be achieved.

Test Specimens

Eight steel frames including one semi-rigid

frame, one rigid frame and six semi-rigid

frameswith various curved dampers were

fabricated for testing to validate the

proposed system’seffective-ness. The test

frame height and span were 2520 mm and

4744 mm, respectively.

Identical columns and beams, H250 250 9

14 and H200 200 8 12, respectively, were

used forall test frames. This combination

formed a strong column/ weak beam

mechanism withstrength ratio equaling 1.88.

For semi-rigid connections, L130 130 12

was used for the topand seat angles and

L100 100 10 with slots were adopted in the

double web angles. The webangles were

used to provide connection shear strength

and the slot was used to maintainstructure

safety should the top and seat angles be

damaged during the loading process.

Forrigid frames, the beam was welded to a

pair of 30-mm end plates and connected to

thecolumns using high strength bolts. The

beam, column, steel angle and curved

dampers wereall made of SN400YB steel

with yield stress equaling 300 MPa, 300

MPa, 314 MPa and 293MPa, respectively.

A574 M high strength bolts were used for all

connections.

Six dampers with various geometries were

selected, based on the finite element

simulationstated above, and installed into

semi-rigid frames to identify the curved

damper effect inimproving framed structure

performance. The curved dampers were

laser-cut from 20-mmsteel plates with

desired geometries. These curved dampers

varied in length (L) and angle (h)between

the two device pin ends. The six dampers

could be divided into three groups, L1, L2