shake table analysis

8/16/2019 shake table analysis

1/26

DESSERT TION ON

Experimental Analysis Of Structure

Using Shake Table

PRESENTED

BY

Pathan Majead Hashamsab

Under the Guidance of

Dr. P. B. MURNAL

Department of Applied MechanicsGovernment College of Engineering,

Aurangabad.(2015 - 2016) 1


2/26

Contents:

1.ntro!uction.

".#iterature sur$ey.

%.Ob&ecti$e.

'.System !e$elopment.

(.)eferences.


3/26

ntro!uction:

Many structures have their fundamental frequencies of vibration within the band of

frequencies .

Structure amplifies the seismic ground vibrations and produces undesirable level of

accelerations .

Cost effective procedure to mitigate such effects is to detach the structure from the

earthquake ground motions.

Main Objective is to keep its response within limits.

The effectiveness of an isolation system depends upon the dynamic characteristics of

the earthquake ground motion and the building superstructure.

eneficial effects of the isolation system may be significantly reduced for both

moderate and strong earthquakes .

!


4/26

*igure 1. +arameters of T,o -egreeof*ree!om solate!"


5/26

!quation of motion in matri" form#

y solving above equation we get characteristic of base isolation.

#


6/26

#iterature sur$ey:

Anoop Mokha(1991):

•$ si" storey model with three bays is used for performing the analysis.•The columns were bolted to two heavy sections and the bearings

were placed between these beams and the shake table.

•The %&S bearings are used.

•$spect ratio of height of model to distance between bearings is '.'(.•&ermanent displacement at the bearings was very small and) in

particular) less than *+ of the bearing design displacement.

• ,n tests with the !l Centro motion) it was shown that the isolated

structure could sustain a peak table acceleration si" times greater than

that it could sustain under fi"ed-base conditions.

$


7/26

Hsiang-Chuan Tsai(1995):•$ five-storey base-isolated building subjected to different earthquake

records.

•$ tuned mass damper is used to reduce the lateral deformations of

isolator.

•little effect on structural response during the first few seconds of

earthquake e"citation.•There e"ists a critical value for the damper damping.•The tuned-mass damper to the structure would enhance the structural

response if the input frequency is lower than the natural frequency of the

structure.

•The reduction by the tuned-mass damper becomes more prominent if the

isolation system has less damping.

•The proposal for the accelerated tuned-mass damper is only conceptional

and idealistic.

%


8/26


9/26


10/26

T. +inkae, 9'66':#5o!el an! !amper:

•'6-storey reinforced concrete building is used.

•$ TM; is installed on top of the structure to reduce the displacement and the

damage.

•oth harmonic and the 2


11/26

). 7iannini 2"3384:

5o!el an! isolation system:

•$ steel liquid storage tank with a diameter of > m is used.

•Two type of isolators are used as high damping rubber bearings and sliding

isolators with elasto-plastic dampers.

Conclusion:

•oth the isolators work effectively in reducing the total pressure generated by

the earthquake on the tank wall.

• $ low increasing of the oscillation amplitude of the liquid surface has been

observed.

11


12/26

A9lan A-A 2"3114:

5o!el an! solation system:

•The '-storey special moment resistant frame is used.

• Solid rubber bearings 9S1: and ?ollow rubber bearings 9?1: are used.

Conclusion:

•The equivalent viscous damping of ?1 is >+ higher than S1.

•1ecorded floor acceleration decrements of the ?1 are @.2+) /.'+ and 26.


13/26

Tomas9 *alborski 2"31"4:

5o!el an! isolation system:

• $ single-storey structure model is used.

•The type of the isolation system is elastomeric polymer isolator.

Conclusion :

•The structure with the !& showed a significant decrease in lateral

acceleration.

•The free vibration test showed a considerable increase in structural damping.

•The use of the !& showed a substantial improvement in dynamic properties

by reducing the structural vibrations.

1!


14/26

#. Tashko$ ; #.


15/26

Emiliano 5atta 2"31%4 : 5o!el an! !amping:

•single and multi degrees-of-freedom linear structures are used.

•Tuned mass dampers are used as damping devices.

Conclusion :

• $s far as peak displacement is concerned) the effectiveness of a TM; on a

S;O% structure is similar to that of a TM; of equal effective mass ratio on a

M;O% structure.

•1MS velocity or peak acceleration is considered) the effectiveness in theM;O% case decreases with an increase in the structural period as a result of

uncontrolled higher modes) whereas for the S;O% case) it keeps nearly

constant.

1#


16/26

A. #ucchini 2"31'4:

5o!el an! !amping:

•/-story shear-type building.

•TM;s are installed in the building where more free spare space is available

to house the devices) which is usually at the roof or at the top floor.

•Conclusion:

•Aith the increase of the total mass of the TM; system) its performance tends

to improve the building response

•Aith the increase of the uncertainty level) it has been observed that period

and damping of the TM; units increase

1$


17/26


18/26

Ob&ecti$e:

•The structure model is subjected to harmonic loading analyBed e"perimentally

under different conditions .

Ob&ects :

• To study the behavior of the structural model when it is fi"ed.

•To analyBe the structural model when it is base isolated.

•To study the behavior of the structural model when TM; is used.

•To study the behavior of the structural model when it is base isolatedand TM; is used.

•To make the comparison of the above cases.

1&


19/26

SSTE5 -E=E#O+5ETShake Table Use!:

•The electric motor driven shake table is used for applying the harmonic

loading to the structural model.

*ig Electric motor !ri$en shake table *ig. Cam > follo,er arrangement *ig. Types of cams

1'


20/26

5O-E# TO ?E USE-:

Geometric data of the structure:

r! "o! #art $imension in mm

Depth idth *ength

1 Column ! # 1

+lab 1 1# !

he column and slab are made up ofaluminum.

Mass of structure is %.1"-g.

ime period of structure is .!$ sec.

Ta%&e : $imension of mode&

*ig. Three storie! mo!el.


21/26

1

he natural freuencies and mode shapes of model/

'1 ! H*

0 %."% 20! 11.$2

he top 3oor acceleration and the relative displacement of structure is

calculated using sha-e table . he follo4ing graph sho4s top 3oor acceleration for di5erent freuenciesfor 67ed structure.

" $ & 1 1 1"

1

!

"

#

$

+re,uenc(H*)

Top +&oor Acce&eration(g)

*ig. *re@uency $s Top *loor Acceleration.

. Mode .. Mode ... Mode

1 1 1.%" .#%1 81.1%

!.#'1 81.1& ."&


22/26

solate! structure :

The structure to be isolated 01 isolation system is selected and designed the dimension

comes out as sown in figure.

The stiffness of 01 is about @6 3m.

Springs are used as isolation system so that to achieve such a small stiffness.

"

"

!

!

"$

*ig. -imension of #)? 2!imensions n mm4

/ f


23/26

/eferences:•$noop Mokha D!"perimental Study Of %riction-&endulum ,solation SystemE)

Fournal of Structural !ngineering) Gol. 22@) 3o. >) &aper 3o. '(@4/.2


24/26

•1. =iannini DShaking Table Tests Ipon $ ase ,solated Steel 0iquid

storage TankE) The2>th Aorld Conference on !arthquake !ngineering

October 2'-2@) '66/) eijing) China.• $Blan $dnan DSeismic ase ,solation of Steel %rame Structure by ?ollow

1ubber earingsE) =aBi Iniversity Fournal of Science vol '>) 3o. >) />2-/(4)'622.•TomasB %alborski) DShaking table e"perimental study on the base isolation

system made of polymer bearingsE) 2(th Aorld Conference on !arthquake

!ngineering 0,SO$ '62'.

•0. Tashkov K 0. Lrstevska DComparison etween Three ase ,solationSystems-Shake Table Test StudiesE) '624.•!miliano Matta D!ffectiveness of Tuned Mass ;ampers against =round

Motion &ulsesE) Fournal of Structural !ngineering) Gol.24


25/26

•$. 0ucchini D1obust ;esign of Tuned Mass ;amper Systems for Seismic

&rotection of Multistory uildingsE) Fournal of Structural !ngineering)'62>.

• %.C. &onBo DShaking table tests of a base isolated structure with double

concave friction pendulumsE) 3JS!! Conference paper 3o.6>4)'62>.

• Leri 0. 1yan D,nfluence of Gertical =round Shaking on ?oriBontal

1esponse of Seismically ,solated uildings with %riction earingsE) Fournal

of Structural !ngineering)'62(.

• Manual of the Millenium ltd of shake table.

#


26/26

Thank you!

$

shake table analysis

Documents