Active Isolation

OUTLINE 1.

INTRODUCTION

2.

LITRATURE REVIEW

3.

SEGMEN SEGM ENT TAL BU BUIL ILDI DING NG & BAS BASEE-IS ISOL OLA ATED TED STIFFENED SUPERSTRUCTURE BUILDING

4.

PROGRA GRAM FOR MDOF SYSTEM TEM

5.

PROGRAM VERIFICATION

6.

WORK TO BE DONE IN NE NEX XT PHAS HASE

7.

REFERENCES

1 INTRODUCTION INTRODUCTION Earthquake Resistance Methods

Ductile Detailing Method

Response Control Methods

Detailing of Reinforcement as per Active Control IS-13920 Provisions Passive Control Methods Methods Active Mass Damping Active Bracing Active - Hybrid Active Tendons

•

•

•

Control Methods

Semi-Active Control Methods

Base-Isolation Stiffness Control Devices Energy Dissipation Electro/Magneto Semi-Active Hybrid Damper Tuned Mass Damper Rheological Control Friction Methods Control Devices •

•

•

•

•

•

DUCTILE DETAILING DETAILING METHOD FOR EARTHQUAKE EARTHQUAKE RESISTANCE Ductility of structure is enhanced by proper ductile detailing of

•

reinforcement. •

Ductility can be achieved only through yielding of structural

members during earthquake. Following the yielding, structure shows large structural and

•

non-structural damage. •

Performance of intended ductile structures have proved to be

unsatisfactory earthquake.

and

far

below

expectation

during

past

PASSIVE CONTROL METHODS 



To enhance structural safety and integrity against earthquake Base-isolation is Most Promising Alternative.

Base isolation is Decoupling of Building by introducing Low Horizontal Stiffness Bearing between structure and foundation.

SUITABILITY OF BASE ISOLATION









The sub-soil does not produce a predominance of Long Period Ground Motion.

Structure is Fairly Squat and with sufficiently High Column Load.

The site permits horizontal Displacements At The Base of The Order of 200 mm or More.

Lateral Loads Due to Wind are Less than approximately 10% of the weight of structure.

NEED FOR PRESENT STUDY •

An empirical formula for time period for multi- storey structure with N storeys is T n = 0.1 ·N

•

Taking a look at response spectra curve given in IS:1893(PART 1): 2002

•

•

•

Significant benefits of base isolation can be obtained in LowRise Structures (less than 10-storeys). Tall structures have high time period, so they Attract Less Earthquake Force. Despite of high flexibility following requirements have attracted engineers to apply base-isolation to tall structures. 1. Comfort of occupants 2. When Contents of building are More Valuable then building itself. 3. High-precision factories and building with Sensitive Equipments. 4. Buildings that should remain Operational Immediately After Earthquake like hospitals, police-stations, telecommunication stations etc.

LIMITATION OF BASE-ISOLATED TALL BUILDINGS •

•

•

•

Susceptible To Resonance under long period ground motion.

Area with Loose Soils produces Long Period Ground Motions.

Drift in tall Uncontrollable.

flexible

building

might

become

Base-displacement Becomes Large so proper care should be taken for connection and installation of services at base-isolation level.

OBJECTIVE OF STUDY To study performance of Segmental Building with Laminated Rubber Bearing under different Near Fault and Far Fault Ground Motion. 

To verify Effectiveness Of Segmental Building compared to conventionally base-isolated system and fixed-base buildings. 

To study performance of Segmental Building with ActiveHybrid Control System under different Near Fault and Far Fault Ground Motion. 

To carry out parametric study and comparison of Segmental Building With Active-Hybrid And Passive Control. 

2. LITRATURE REVIEW Number of papers have been published on Structural Control for Tall Buildings. Excellent reviews being published on the control concepts and applications are available in papers of Pan, Jain, Ariga, Matsagar etc.

PAN et al. (1995) investigated dynamic characteristic of Segmental Building with Isolator with Optimum Parameters Subjected to N-S El Centro Ground Motion and carried out comparision with fixed base and base isolated building. it was found that segmantal building possesed ability to Isolate Building Similar to Base Isolated Building and Also Significantly Reduces Overall Displacement.

PAN et al. (1998) investigated response of Segmental Building to a Random Seismic Excitation and concluded that segmental building decouple building from ground excitation and considerable Reduction in Displacement at Base Level Compared Base Isolated Building .

JAIN et al. (2004) stiffened superstructure with 10, 14 & 20 storeys were subjected to different earthquake motion and observed Considerable Reduction In Maximum Roof Acceleration & Maximum Storey Drift but storey shear and base displacement increased due to stiffening.

ARIGA et al. (2006) investigated the Resonant Behaviour of Base-isolated High-Rise Building under long period ground motion induced by surface waves and concluded that friction type isolators have remarkable characteristics unfavorable to long period ground motion.

JANGID (2004) discussed problem of sliding structure which is discontinuous one as different set of equation with Varying Force Function are Required for Sliding and Non-sliding Phase. Comparative study of conventional model and hysteretic model of frictional force is carried out.

PRANESH et al. (2002) carried out parametric study of Multistory Building with VFPI and found it Stable During Low and Medium Intensity Excitation and Fails Safe During High Intensity Ground Motion .

SPENCER et al. (2003) discussed the recent development in smart control systems and discussed advantages of semi-active devices due to their mechanical simplicity, low power requirement and large controllable force capacity.

Dutta (2003) ) gave state-of-art review of Active Controlled Structures. Theoretical backgrounds of different active control schemes, Important Parametric Observations on Active Structural Control, Limitations and Difficulties in Their Practical Applications were discussed.

CONCLUDING REMARK The review of literature revels that Structural Control Technique Is Inevitable Earthquake Resistant Design Method . It also gives idea about performance and Advantages Of Passive, Active And Semi-active control systems. Some papers shows that despite of longer time period Baseisolation Can Still Be Implemented In Tall Buildings and also discuss about Resonant Behavior of isolated structures under long period ground motion

3. SEGMENTAL BUILDING •

It is extension of the conventional base isolation technique with a Distributed Flexibility In The Superstructure.

SEGMENTAL BUILDING

BASE ISOLATED BUILDING

FIXED BASE BUILDING

As the Building Is Divided In Number Of Segments this type of building is known as segmental building. •

Each Segment is Comprise of Few Storey and is Interconnected by Vibrational Isolator system. •

Absorption and dissipation of earthquake energy are Afforded By Isolators At All Level rather than at base-isolator level only. •

Order of Displacement Demand at Base Level is Less than solely base-isolated building. •

PRACTICAL APPLICATION OF SEGMENTAL BUILDING

MODEL OF BASE-ISOLATED BUILDING OVER RAILWAY PLATFORM (CHINA)

SHIODOME SUMITOMO BUILDING (JAPAN)

DONG-II HIGH VILL CITY BUILDING (KOREA) ISOLATORS ARE INSTALLED AT 8 – STOREY ABOVE PARKING

4. FLOW CHART FOR RESPONSE OF MULTI-DEGREE FREEDOM SYSTEM INPUTS •

Number Of Storeys

•

Mass

•

Stiffness

•

Damping Of Structure

•

Properties Of Isolators

•

Ground Excitation

•

•

•

Stodola – Vianello’s Method is Adopted for Eigen Value and Eigen Vector Solution.

Super-Position of Modal Damping Matrix is Used for Construction of Damping Matrix.

Newmark’s Step-By-Step Integration Method assuming Linear Variation in Acceleration is Adopted For Time History Analysis.

READ INPUT DATA

FORM DIAGONAL MASS MATRIX

FORMATION OF STIFFNESS MATRIX

FORMATION OF DAMPING MATRIX

ASSIGN BASE ISOLATOR PROPERTIES

NUMERICAL EVALUATION OF DYNAMIC RESPONSE USING

STEP BY STEP INTEGRATION TECHNIQUE

INTERPRETATION & COMPARISION OF RESPONSE

5. PROGRAM VERIFICATION

•

Program Verification For Fixed Base Building

•

Program Verification For Base-isolated Building

•

Program Verification For Segmental Building

PROGRAM VERIFICATION FOR FIXED BASE BUILDING Five-Storey Shear Frame (Chopra, A. K. (2000). Dynamics Of Structures: Theory And Applications To Earthquake Engineering, 2nd Ed., Prentice–hall, Upper Saddle River, N.J.)

DATA

Storey Height (h) =

12 ’

Mass (m) =

100 kips/g

Storey Stiffness (k) =

31.54 kips/in.

Damping Ratio (ζ ) =

5%

Subjected To N-S Component Of EL CENTRO Ground Motion

TABULAR COMPARISON Natural Time Period Mode of Vibration

Program Output

Chopra

First

1.9996

2.0000

Second

0.6850

0.6852

Third

0.4346

0.4346

Fourth

0.3383

0.3383

Fifth

0.2966

0.2966

Response

Program Output

Chopra

Peak roof displacement (inch)

6.841

6.847

Peak base shear (kips)

73.179

73.278

Peak fifth storey shear (kips)

35.083

35.217

Peak base overturning moment (kips-ft)

2589.2

2593.2

GRAPHICAL COMPARISON

ROOF DISPLACEMENT FROM PROGRAM

ROOF DISPLACEMENT FROM CHOPRA

BASE SHEAR FROM PROGRAM

BASE SHEAR FROM CHOPRA

ROOF SHEAR FROM PROGRAM

ROOF SHEAR FROM CHOPRA

BASE-OVER TURNING MOMENT FROM PROGRAM

BASE-OVER TURNING MOMENT FROM CHOPRA

PROGRAM VERIFICATION FOR BASE-ISOLATED BUILDING Five Storey Base-Isolated Shear Frame (Matsagar, V. A. and Jangid, R. S. (2003) “Seismic Response of Base-Isolated Structures During Impact with Adjacent Structures” Engineering Structures, Elsevier, 25, 2003.)

Type Of Isolator

LRB

Superstructure Time Period

0.5 SEC

Base-isolator Time Period

2.0 SEC

Superstructure Damping Ratio

0.02

Base-isolator Damping Ratio

0.10

Mass Ratio (M B / M)

1.0

•

•

•

•

•

•

Subjected To N00E Component Of 1989 LOMA PRIETA Earthquake Recorded At LOS GATOS PRESENTATION CENTER •

BEARING DISPLACEMENT FROM PROGRAM

BEARING DISPLACEMENT FROM MATSAGAR

TOP FLOOR ACCELERATION FROM PROGRAM

TOP FLOOR ACCELERATION FROM MATSAGAR

VERIFICATION OF PROGRAM FOR SEGMENTAL BUILDING (Pan, T. C., Ling, S. F. and Cui, W. (1995) “Seismic Response of Segmental Buildings” Earthquake Engineering and Structural Dynamic, 24,1039-1048)

Number Of Storeys

16

Height Of Storey

3m

Number Of Storey In Segment

4

Modal Damping Ratio

5%

•

•

•

•

N-S COMPONENT EL CENTRO EARTHQUAKE

•

Isolator Properties

•

LEVEL OF ISOLATOR

LATERAL STIFFNESS 108 N/m

Ground Level

1.11

Fourth Floor

12.9

Eighth Floor

6.76

Twelfth Floor

2.14

PROPERTIES OF SEGMENT STIFFNESS OF STOREY THROUGH OUT SEGMENT LEVEL

STIFFNESS (N/m)

FIRST (BOTTOM MOST)

2.4 x 109

SECOND

1.29 x 109

THIRD

6.76 x 108

FOURTH TOP

3.15 x 108

MASS OF STOREY IN INDIVIDUAL SEGMENT STOREY

MASS (kg)

ISOLATED RAFT

2.52 x 105

INTERMEDIATE LEVELS

3.49 x 105

SEGMENT ROOF MASS

1.39 x 105

TABULAR VERIFICATION OF NATURAL FREQUENCY (Hz) Program Output

0.55

1.37

2.55

4.02

4.68

Pan et al. (1995)

0.54

1.35

2.48

3.92

4.61

FUNDAMENTAL MODE SHAPES

FIRST MODE

SECOND MODE

5. PROGRAM VERIFICATION

THIRD MODE

FOURTH MODE

5. ANALYSIS OF SEGMENTAL , BASE-ISOLATED & FIXED-BASE BUILDING Number Of Storeys

16

Height Of Storey

3m

Number Of Storey In Segment

4

Modal Damping Ratio

5%

•

•

•

•

Isolator Properties Segmental Building

•

LEVEL OF ISOLATOR

LATERAL STIFFNESS 108 N/m

Ground Level

1.51

Fourth Floor

2.76

Eighth Floor

0.57

Twelfth Floor

3.15

Base-Isolated Building - 0.59 x 108 N/m

GROUND MOTIONS CONSIDERED Sr

Record

PGD

PGV

PGA

Component

(cm)

(cm/s)

(g)

1999 Chi-Chi, Taiwan

TCU 047

22.22

40.02

0.413

1979 Imperial Valley

DELTA 352

19.02

33

0.351

3

1995 Kobe

KAKOGAWA 090

9.6

27.6

0.345

4


TCU 129

50.15

60

1.01


El-Cento Array # 8

32.32

54

0.602

1995 Kobe

KJM 000

17.68

81.3

0.821

No

Type

1

Earthquake

Far 2

Fault Motion

Near 5

Fault Motion

6

DYNAMIC PROPERTIES

Natural Frequencies (Hz) Mode 1

Mode 2

Mode 3

Mode 4

Mode 5

F B Model

0.94

2.26

3.66

5.21

6.26

B I Model

0.49

1.55

2.90

4.43

5.64

S B Model

0.46

1.25

2.03

3.01

4.23

FUNDAMENTAL MODE SHAPES 50

50

FB SB BI

40

40

30

30

m t h g i e H20

m t h g i e H20

10

10

0 0.0

0.2

0.4

0.6

0.8

1.0

1.2

Mode 1

50

0 -1.8

-0.6

0.0

0.6

1.2

Mode 2

50

40

40

30

30

m t h g i e H20

m t h g i e H20

10

10

0 -1.2

-1.2

-0.6

0.0

Mode 3

0.6

1.2

0 -8

-4

0

Mode 4

4

8

Reduction in Base Displacements Type

Far Fault Motion

Near Fault Motion

Earthquake

Segmental Building

Base Isolated Building

% Difference

Chi-Chi, Taiwan

0.0617

0.10635

41.98

Imperial Valley

0.06102

0.17152

64.42

Kobe

0.05483

0.2

72.59

Chi-Chi, Taiwan

0.09887

0.17257

42.71

Imperial Valley

0.07338

0.223

67.09

Kobe

0.15858

0.285

44.36

Peak Storey Displacement - 1999 Chi-Chi FF

m t h g i e H

50

50

40

40

30

30

m t h g i e 20 H

20 FB SB BI

10 0 0.00

Peak Storey Displacement - 1995 Kobe FF

0.05

0.10

0.15

10 0 0.00

0.20

Displacement m

0.12

0.24

0.36

Displacement m

Peak Storey Displacement - 1979 Imperial Valley FF 50 40

m t h g i e H

Peak Displacement Response Under Far Fault Ground Motions

30 20 10 0 0.0

0.1

0.2

Displacement m

0.3

Peak Storey Displacement - 1999 Chi-Chi NF

m t h g i e H

Peak Storey Displacement - 1995 Kobe NF

50

50

40

40

30

m t h g i e H

20 10 0 0.0

FB SB BI

0.1

0.2

30 20 10

0.3

0 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Displacement m

Displacement m Peak Storey Displacement - 1979 Imperial Valley NF 50

Peak Displacement Response Under Near Fault Ground Motions

40

m t h g i e H

30 20 10 0 0.00

0.15

0.30

Displacement m

0.45

Top - Storey Acceleration Response

Far Fault

Earthquake

Segmental Building


CHI-CHI FF

0.43288

0.36227

-19.49

IMP VALL FF

0.33166

0.32156

-3.14

KOBE FF

0.33588

0.38119

11.89

CHI-CHI NF

0.60602

0.40546

-49.46

0.47897

0.47121

-1.65

1.09837

0.89199

-23.14

Near Fault IMP VALL NF KOBE NF

%

Difference

Peak Storey Acceleration - 1999 Chi-Chi FF

Peak Storey Acceleration - 1979 Imperial Valley FF

50

50

40

40

30

30

m t h g i e 20 H

m t h g i e 20 H

FB SB BI

10 0 0.0

0.2

0.4

0.6

0.8

10

1.0

0.6

0.9

Absolute acceleration (m/s )

Peak Storey Acceleration - 1995 Kobe FF

Peak Absolute Acceleration Response Under Far Fault Ground Motions

40 30

m t h g i e 20 H

10 0 0.00

0.3

2

Absolute acceleration 50

0 0.0

0.25

0.50

0.75 2


1.00

Peak Storey Acceleration - 1999 Chi-Chi NF

Peak Storey Acceleration - 1979 Imperial Valley NF

50

50

40

40

30

30

m t h g i e 20 H

m t h g i e 20 H

FB SB BI

10 0 0.0

0.8

1.6

10

2.4

2

0 0.0

0.5

1.0

1.5

2



Peak Storey Acceleration - 1995 Kobe NF 50 40

Peak Absolute Acceleration Response Under Near Fault Ground Motions

30

m t h g i e 20 H

10 0 0.0

0.8

1.6

2.4 2


3.2

Reduction in Base-Shear Earthquake

Segmental Building


% Difference

CHI-CHI FF

7.76E+06

7.23E+06

-7.34

9.21E+06

1.17E+07

21.25

KOBE FF

8.28E+06

1.36E+07

39.13

CHI-CHI NF

1.49E+07

1.17E+07

-27.61

IMP VALL NF

1.11E+07

1.52E+07

27.10

KOBE NF

2.39E+07

1.94E+07

-23.43

Far Fault IMP VALL FF

Near Fault

Peak Storey Shear - 1999 Chi-Chi FF

Peak Storey Shear - 1979 Imperial Valley FF

50

50 FB SB BI

40

40

) 30 m ( t h g 20 i e H

) 30 m ( t h g 20 i e H

10

10

0

0 0

1

2

3

4

5

6

7

8

9

10 11 12 13 14 6

0

2

4

6

8

10

12

14

16

6

Storey Shear (N) X10


Peak Storey Shear - 1995 Kobe FF

50 40

Peak Storey Shear Response Under Far Fault Ground Motions

) 30 m ( t h g 20 i e H

10 0 0

2

4

6

8

10

12

14 6


16

18

20

18

Peak Storey Shear - 1999 Chi-Chi NF

Peak Storey Shear - 1979 Imperial Valley NF 50

50

FB SB BI

40

) m ( t h g i e H

40 ) 30 m ( t h g 20 i e H

30

20

10

10

0

0 0

2

4

6

8

10

12

14

16

18

20

22

24

26

6


0

2

4

6

8

10

12

14

16

18

6


Peak Storey Shear - 1995 Kobe NF 50 40

Peak Storey Shear Response Under Near Fault Ground Motions

) 30 m ( t h g 20 i e H

10 0 0

10

20

30

40 6


50

Reduction in Base-Over Turning Moment

Far Fault

Near Fault

Earthquake

Segmental Building


% Difference

CHI-CHI FF

1.60E+08

2.49E+08

35.82

IMP VALL FF

2.62E+08

3.17E+08

17.24

KOBE FF

2.64E+08

3.62E+08

27.07

CHI-CHI NF

2.96E+08

3.20E+08

7.41

IMP VALL NF

3.53E+08

3.98E+08

11.36

KOBE NF

4.69E+08

6.30E+08

25.60

Peak Storey Overturning Moment - 1979 Imperial Valley FF

Peak Storey Overturning Moment - 1999 Chi-Chi FF 50

50 FB SB BI

40

40

m t h g i e 20 H

30

) 30 m ( t h g 20 i e H

10

10

0

0

5

10

15

20

25

Over Turning Moment kN-m 50

30

35

40

7

5

10

15

20

25

30

35

40

45

7

X10

Peak Storey Overturning Moment - 1995 Kobe FF

Peak Over Turning Moment Response Under Far Fault Ground Motions

) 30 m ( t h g 20 i e H

10

0

0

Over Turning Moment (N-m)

X10

40

0

0

11

22

33


44 7

X10

55

Peak Storey Overturning Moment - 1999 Chi-Chi NF

Peak Storey Overturning Moment - 1979 Imperial Valley NF

50

50

40

40

) 30 m ( t h g 20 i e H

) 30 m ( t h g 20 i e H

10

10

0

0

5

10 15 20 25 30 35 40 45 50 55 60 65


7

0

0

FB SB BI

9

18

27


X10

36

45

7

X10

Peak Storey Overturning Moment - 1995 Kobe NF 50 40

Peak Over Turning Moment Response Under Near Fault Ground Motions

) 30 m ( t h g 20 i e H

10 0

0

20

40

60

80

100


120

140 7

X10

160

Hysteresis Damping in Base-Isolated Building 0.15 0.2

0.2

0.1

0.1

0.10

0.05

e c r o F

0.00

e c r o F

e c r o F

0.0

0.0

-0.05 -0.1

-0.1

-0.10

-0.15

-0.10

-0.05

0.00

0.05

Chi - Chi NF

-0.2

Chi - Chi FF 0.10

-0.20

-0.15

-0.10

Displacement

-0.05

0.00

0.05

0.10

0.1 5

Imperial Valley FF

-0.2

0.20

-0.20

-0.15

-0.10

-0.05

0.00

0.05

0.10

0.1 5

0.20

Displacement

Displacement

0.3 0.4

0.3 0.2

0.3

0.2 0.2 0.1 0.1

e c r o F

0.1

e c r o F

0.0

e c r o F

0.0

-0.1

-0.1

-0.1

0.0

-0.2 -0.2

-0.2

Kobe FF

Imperial Valley NF -0.3

-0.3 -0.2

-0.1

0.0

0.1

Displacement

0.2

0.3

-0.2

-0.1

0.0

Displacement

0.1

0.2

-0.3

Kobe NF -0.4 -0.3

-0.2

-0.1

0.0

0.1

Displacement m

0.2

0.3

Hysteresis Damping in Segmental Building th

th

12 Storey Isolator

th

8 Storey Isolator

0.10

0.3

th

12 Storey Isolator

8 Storey Isolator

0.06

0.00

0.00

e c r o F-0.03

0.30

0.2

0.05

0.03

e c r o F

0.1

0.15

e c r o F 0.0

e c r o F 0.00

-0.05 -0.1

-0.06 -0.10

-0.09 -0.014

-0.007

0.000

0.007

-0.15

-0.2 -0.10

Displacement (m)

-0.05

0.00

0.05

0.10

-0.04

-0.02

Displacement (m)

0.14

0.18

0.07

0.09

e c r o 0.00 F

e c 0.00 r o F

-0.07

-0.09

0.02

0.04

-0.30

-0.2

0.0

Displacement(m)

0.4

0.2

0.4

Displacement(m)

Base-Isolator

th

Base-Isolator

th

4 Storey Isolator

0.00

4 Storey Isolator

0.50

0.25

0.2

e c r o F 0.0

e 0.00 c r o F

-0.25 -0.2

-0.14

-0.02 -0.01 0.00

0.01

Displacement (m)

0.02

0.03

-0.18 -0.08

-0.04

0.00

0.04

Displacement (m)

1999 Chi-Chi – TCU 047 Far Fault

0.08

-0.06

-0.03

0.00

0.03

Displacement (m)

0.06

-0.50 -0.2

-0.1

0.0

Displacement (m)

1995 Kobe – KJM 000 Near Fault

0.1

4. ACTIVE-HYBRID CONTROL OF SEGMENTAL BUILDING Combination of Active Control Devices and Passive Control Devices is known as Active-hybrid Control •

Actuators are installed at segment level along with Laminated Rubber Bearings in segmental building •

Pole Placement Technique is used as Control Algorithm for generation of control forces. •

ACTIVE CONTROL OF STRUCTURES EXTERNAL EXCITATIONS

STRUCTURE

STRUCTURAL RESPONSE

CONTROL FORCES

CLOSED-LOOP

OPEN-LOOP

SENSORS

SENSORS

SYSTEM

SYSTEM

ACTUATORS

COMPUTATION OF CONTROL FORCES

When Only Structural Response Variables are measured the control configuration are known as Closed-Loop or Feed-Back System. •

When Only Excitation are measured the control configuration are known as Open-Loop or Feed-Front System.

•

When information of both Response Quantities and External Excitation are measures for control design it is known as ClosedOpen-Loop System. •

•

System used in present study is Closed-Loop System.

PROBLEMS IN REAL-TIME APPLICATIONS

•

Modeling error •

•

•

Time Delay

Limited Sensors and Controllers

Parameter Uncertainty and System Identification •

Discrete Time Control •

•

Reliability

Cost-Effectiveness and Hardware Requirements

EQUATION OF MOTION OF CONTROLLED STRUCTURE

D Is Location Matrix u Is Control Force Vector And Is Proportional To ẋ, x and Ground Excitation

K 1, C1, E Are Time Independent Matrix

Control Depends On How K 1 And C1 Are Obtained

STATE-SPACE EQUATION Using State-space Second Order Differential Equation Of Motion Is Converted In First Order Equation Let Equation Of Motion Be

State-space Equation For Controlled Motion Will Be

Where G Is Gain Matrix And D Is Position Vector

ACTIVE CONTROL ALGORITHMS Number of active algorithms are developed for finding control force u(t). •

Most of algorithm derive control force by minimizing the norm of some response therefore termed as Optimal Control Algorithm. •

The derived control forces are linear functions of state vector hence are also known as Linear Optimal Control Algorithm. •

There are also some algorithm that are not based on optimal criterion but on stability criterion or some other considerations. •

Also control algorithms have control forces in terms non-linear functions of state vector. •

CONTROL ALGORITHMS

Pole Placement Technique / Pole Assignment Technique

•

Classical Linear Optimal Control / Linear Quadratic Regulator (LQR)

•

•

Instantaneous Optimal Control Closed – Open Loop Control

•

Independent Modal Space Control (IMSC)

•

Bounded State Control

•

And some other FUZZY Controls and Predictive Controls.

•

POLE-PLACEMENT TECHNIQUE State-Space Equation For Controlled Motion

Eigen values of A are poles of uncontrolled systems. systems. Eigen values of Ᾱ are poles of uncontrolled systems. The poles of system is given by

S - PLANE Imaginary

Stable Region

Unstable Region Real

Desired poles are selected such that they are on left side of uncontrolled uncontrolled pole. •

Choice of desired poles depends upon percentage of control forces and amount of peak control force required. •

After selecting poles of controlled system system the Gain matrix G is obtained to generate control forces. •

FEEDBACK GAIN MATRIX Ackermann’s formula is used to calculate G – Feedback Gain Matrix.

MATLAB has standard programs for calculation of gain matrix i.e. acker - for Ackermann’s formula for SDOF systems place – for MDOF systems.

For calculating G matrix A, B, and J – Desired Pole Matrix are required e.g. G = acker(A,B,J) G = place(A,B,J)

COMPUTATION OF RESPONSE First order linear differential equation of motion

Equation is solved using Linear Time Invariant Simulation function of MATLAB i.e. lsim On solving equation we get displacement and velocity responses of building. •

VERIFICATION OF PROGRAM FOR ACTIVE CONTROL USING POLE PLACEMENT TECHNIQUE Five-Storey Shear Frame With Actuator At Top Storey (Dutta, T. K. (2010). Seismic Analysis of Structures , John Wiley & Sons (Asia) Pte. Ltd.)

DATA

Storey Height (h) =

4m

Mass (m) =

150000 kg

Storey Stiffness (k) =

200000 kN/m.

Damping Ratio (ζ ) =

5%

Actuators are installed at top storey Subjected to N-S Component of EL CENTRO ground motion

Uncontrolled Poles

Desired Poles

-6.260

+

71.858 i

-10

+

71 i

-6.260

-

71.858 i

-10

-

71 i

-5.173

+

64.864 i

-10

+

70 i

-5.173

-

64.864 i

-10

-

70 i

-3.416

+

51.527 i

-10

+

30 i

-3.416

-

51.527 i

-10

-

30 i

-1.658

+

33.113 i

-10

+

12 i

-1.658

-

33.113 i

-10

-

12 i

-0.571

+

11.410 i

-22

+

0.4 i

-0.571

-

11.410 i

-22

-

0.4 i

DISPLACEMENTS OF FIFTH STOREY

0.08

Controlled Response Uncontrolled Response

0.06 0.04

) 0.02 m ( t n e 0.00 m e c a l -0.02 p s i D -0.04 -0.06 -0.08

0

5

10

15

Time (s)

20

25

30

DISPLACEMENTS OF FIRST FLOOR

0.03

Controlled Response Uncontrolled Response

0.02

) 0.01 m ( t n e 0.00 m e c a l p s -0.01 i D -0.02

-0.03

0

5

10

15

20

25

30

Comparison of Peak Base Displacement (cm)

Type

Earthquake

Active Control

Passive Control

% Differenc e

Far


5.11

6.17

17.18

Field


4.31

6.10

29.34

Motion

1995 Kobe

3.45

5.48

37.04

Near


8.15

9.89

17.59

Fault


5.42

7.34

26.16

Motion

1995 Kobe

12.13

15.86

23.52

Comparison of Roof Displacement (cm)

Type

Earthquake

Active

Passive

Control

Control

% Differenc e

Far


8.66

17.66

50.96

Field


18.92

28.82

34.35

Motion

1995 Kobe

14.33

30.05

52.31

Near


20.19

29.52

31.61

Fault


21.62

40.10

46.08

Motion

1995 Kobe

31.29

48.52

35.51

Comparison of Peak Storey Displacement - 1999 Chi-Chi FF 50

50

40

40

30

Comparison of Peak Storey Displacement - 1979 Imperial Valley FF

30

) m ( t h g 20 i e H

) m ( t h g 20 i e H

10

10

Controlled Uncontrolled 0 0.00

0.03

0.06

0.09

0.12

0.15

0.18

Displacement (m)

50

0 0.00

0.05

0.10

0.15

0.20

0.25

Displacement (m)

Comparison of Peak Storey Displacement - 1995 Kobe FF

40

Peak Storey Displacement Response Under Far Fault Ground Motions

30

) m ( t h g 20 i e H 10

0 0.00

0.05

0.10

0.15

0.20

Displacement (m)

0.25

0.30

0.35

0.30

50

Comparison of Peak Storey Displacement - 1999 Chi-Chi NF

50

40

Comparison of Peak Storey Displacement - 1979 Imperial Valley NF

40

30

30

) m ( t h g 20 i e H

) m ( t h g 20 i e H

10

10

Controlled Uncontrolled 0 0.00

0.05

0.10

0.15

0.20

0.25

0.30

Displacement (m)

50

0 0.00

0.06

0.12

0.18

0.24

0.30

0.36

0.42

Displacement (m)

Comparison of Peak Storey Displacement - 1995 Kobe NF

40

Peak Storey Displacement Response Under Near Fault Ground Motions

30

) m ( t h g 20 i e H 10

0 0.0

0.1

0.2

0.3

Displacement (m)

0.4

0.5

Comparison of Peak Base Shear X10 6 (N)

Active

Passive

%

Control

Control

Difference


7.72

9.32

17.17


6.51

9.22

29.39

1995 Kobe

5.21

8.29

37.15

Near


12.30

14.93

17.62

Fault


8.19

11.08

26.08

Motion

1995 Kobe

18.32

23.91

23.38

Type

Far Field Motion

Earthquake

1999 Chi-Chi - TCU 047

1979 Imperial Valley - DELTA 352

50

50

Controlled Uncontrolled

40

40

30

30

) m20 ( t h g i e H10

) m20 ( t h g i e H10

0

0

2

4

6

8

10

6

Storey Shear X10 (N)

0

0

2

4

6

8

10

6


1995 Kobe - KAKOGAWA 090 50 40

Peak Storey Shear Response Under Far Fault Ground Motions

30 ) m20 ( t h g i e H10

0

0

2

4

6 6


8

10

1979 Imperial Valley - El-Centro Array#8

1999 Chi-Chi - TCU 129 50

50

40

40

30

30

) m20 ( t h g i e H10

) m20 ( t h g i e H10

0

0

4

8

12

16

6

0

0

3

6

9

12

6



1995 Kobe - KJM 000 50 40

Peak Storey Shear Response Under Near Fault Ground Motions

30 ) m20 ( t h g i e H10

0

0

5

10

15 6


20

25

Comparison of Peak Base Over-Turning MomentX108 (N-m)

%

Active

Passive

Control

Control


0.93

1.60

41.88


1.64

2.62

37.40

1995 Kobe

1.34

2.64

49.24

Near


2.46

2.96

16.89

Fault


2.01

3.53

43.06

Motion

1995 Kobe

2.71

4.69

42.22

Type

Far Field Motion

Earthquake

Differenc e



50

50

Controlled Uncontrolled

40

40

30

30

) m20 ( t h g i e H10

) m20 ( t h g i e H10

0

0

3

6

9

12

7

15

18

0

0

7

14

21 7

Over-Turning Moment X10 (N-m)

Over Turning Moment X10 N-m

1995 Kobe - Kakogawa 090 50

40

Peak Over Turning Moment Response Under Far Fault Ground Motions

30 ) m20 ( t h g i e H10

0

0

5

10

15

20

25 7


30

28


50

1979 Imperial Valley - El-Centro Array#8 50

40

40

30

30

) m20 ( t h g i e H10

) m20 ( t h g i e H10

0

0

5

10

15

20

25

30

7

0

0

6

12

18

24

30

36

7



1995 Kobe - KJM 000 50

40

Peak Over Turning Moment Response Under Near Fault Ground Motions

30

) m20 ( t h g i e H10

0

0

10

20

30

40 7


50

Peak Control Force

Type

Far Field Motion

Near Fault Motion

Earthquake

Control Force X103 (kN)


8.66


18.92

1995 Kobe

14.33


20.19


21.62

1995 Kobe

31.29


2


1.5 1.0

1 0.5 0 1 X ) 0.0 N ( e c r -0.5 o F -1.0

6

6

0 1 X ) 0 N ( e c r o F -1

-2 0

19

38

57

76

95

Time (s)

0

20

40

60

80

100

Time (s)

1995 Kobe - Kakogawa 090

1.4

0.7

Control Force History Under Far Fault Ground Motions

6

0 1 X ) 0.0 N ( e c r o F -0.7

-1.4

-1.5

0

11

22

Time (s)

33

44

3


1979 Imperial Valley - El-Centro Array#8 2

2 1 0 1 X ) 0 N ( e c r o F -1

1 0 1 X 0 ) N ( e -1 c r o F -2

6

-3 0

6

19

38

57

76

95

Time (s)

10

20

30

40

Time (s)

1995 Kobe - KJM 000

4

Control Force History Under Near Fault Ground Motions

2 6

0 1 X ) 0 N ( e c r o F -2

-4 0

-2 0

10

20

30

Time (s)

40

50

Comparison Of Isolator Displacement Subjected To 1999 Chi-Chi – TCU 047 th

Isolator Displacement at 12 Storey

0.016

) m 0.008 ( t n e 0.000 m e c -0.008 a l p s i -0.016 D

Uncontrolled Controlled

30

60

Time (s) th

) m ( t n e m e c a l p s i D


0.10 0.05 0.00 -0.05 -0.10

30

60

Time (s) th




0.026 0.013 0.000 -0.013 -0.026

30

Time (s)

60

Isolator Displacement at Ground Level

0.064 0.032 0.000 -0.032 -0.064

30

Time (s)

60

Comparison Of Isolator Displacement Subjected To 1995 KOBE – KJM000 th

) m (

t n e m e c a l p s i D

) m (


) m (


Uncontrolled Controlled

0.02

t n e 0.00 m e c -0.02 a l p s i -0.04 D

) m (


0.04

10

20

Time (s) th Isolator Displacement at 8 Storey

0.26 0.13 0.00 -0.13 -0.26

0.06 0.04 0.02 0.00 -0.02 -0.04 -0.06

10

20

Time (s) th Isolator Displacement at 4 Storey

10

20

Time (s) Isolator Displacement at Ground Level

0.150 0.075 0.000 -0.075 -0.150 10

20

Time (s)

Comparison Of Hysteresis Hysteresis Damping

1999 Chi-Chi – TCU 047

1999 Chi-Chi – TCU 129

5. CONCLUSION & FUTURE SCOPE Segmental Building With Passive Passive Control Natural Time Period of segmental building is Higher compared to other so attracted earthquake force is lower •

Reduction of Average 56% in Peak Base Displacement is obtained in segmental building compared to base-isolated

•

Increase of 14 % in Peak Roof Acceleration is noticed in segmental building compared to base isolated building but it is remarkably low compared to fixed-base building. •

Average 5 % Reduction in Storey Average Storey Shear response is seen in segmental building compared to base-isolated building under set of near fault and far fault ground motions. •

Average Reduction of 21 % is Seen in Peak Base Over-Turning Average Over-Turning Moment in segmental building compared to base isolated building. •

A Large Amount of Energy is Dissipated at Different Levels in segmental building when compared to base-isolated building. •

Segmental Building With Active-Hybrid Active-Hybrid Control Average Reductions of 25% in Peak Base Displacement while 42 % in peak roof displacement is seen in controlled building over uncontrolled building subjected to both near fault and far fault ground motion. •

Reduction of Average 23 % in Peak Base Shear is seen on controlled building over uncontrolled building •

Reduction of Average 21 % in Peak Base Overturning Moment is seen in controlled building compared to uncontrolled building •

Due to reduced displacements and introduction of control force Very Less Amount of Energy is Dissipated by Isolators in Controlled Building when compared to uncontrolled building. •

Based on above observations, it is concluded that Segmental Building Appears to Hold the Promise of Extending Passive and Active-h Active-hybrid ybrid Control Technique to Mid-rise Buildings also which is still restricted to low-rise buildings.

Future Scope Comparative study on response of segmental building with Variation of Number of Storeys in Each Segment. •

Response of segmental building with Other Friction Base and Elastomeric Isolators under different ground motion. •

Response of segmental building with passive and active control under Action of Wind Load. •

Response of segmental building with Semi-Active And Hybrid Aemi-Active Control Systems under seismic and wind loads. •

Experimental evaluation of seismic performance of segmental building with passive and active control. •

REFERENCES Ariga, T., Kanno, Y., Takewaki, I.(2006) “Resonant Behaviour of BaseIsolated High-Rise Buildings Under Long-Period Ground Motions ” Journal of the Structural Design of Tall and Special Buildings, 15, 325-338. •

Chopra, A K “Dynamics of Structures” Pearson Education. Inc.

•

Clough, R. W. & Penzien, J. “ Dynamics of Structures” Mc Graw Hill, Inc.

•

Craig, R. R. Jr. “Structural Dynamics” John Wiley & Sons

•

Deb, S. K. (2004) “Seismic Base Isolation – An Overview ” Special Section: Geotechnics and Earthquake Hazards; Current Science, 87. •

Dutta, T. K. “ Seismic Analysis of Structures” , John Wiley & Sons (Asia) Pte. Ltd •

Hong, W. K., Kim, H. C. (2004) “ Performance of a multi-story structure with a resilient-friction base isolation system ” Computers and Structures, 82, 2271-2283 •

Jain, S. K. & Thakkar, S. K. (2004) “ Effect of Super Structure Stiffening On Base Isolated Tall Building” I E (I) Journal, 85,142-148. •

Jangid, R. S. (2004) “ Computational Numerical Models for Seismic Response of Structure Isolated By Sliding Systems” Structural Control and Health Monitoring. •

Kelly, J. M. (1986) “ Aseismic base isolation: review and bibliography” Journal of soil Dynamics and Earthquake Engineering, 5, 202-216. •

Matsagar, V. A. and Jangid, R. S. (2003) “Seismic Response of BaseIsolated Structures During Impact With Adjacent Structures ” Engineering Structures, Elsevier , 25, 2003. •

Pranesh, M. and Sinha, R. (2000) “VFPI: An Isolation Device for A Seismic Design” Journal of Earthquake Engineering and Structural Dynamics, 29, 603627. •

Pranesh, M. and Sinha, R. (2002) “Earthquake Resistance Design of Structures using the Variable Frequency Pendulum Isolator” ASCE , 128, 870-880. •

Mukhopadhyay, M. “Vibrations, Dynamics & Structural Systems ” Oxford & IHB Publishing Co. Pvt. Ltd. •

Pan, T. C., Ling, S. F. and Cui, W. (1995) “ Seismic Response of Segmental Buildings” Earthquake Engineering and Structural Dynamic, 24,1039-1048. •

Pan, T. C., Cui, W. (1998) “Response of Segmental Buildings To Random Seismic Motions” Iset Journal of Earthquake Technology, 35, 378.

•

Paz, M. “Structural Dynamics” Van Nostrand Reinhold Company, Inc.

•

Soni, D. P., Mistry, B. B., Jangid, R. S. and Panchal, V. R. (2010) “Seismic Response of The Double Variable Frequency Pendulum Isolator ” Structural Control and Health Monitoring. •

Soni, D. P., Mistry, B. B. and Panchal, V. R. (2010) “ Behaviour of asymmetric building with double variable frequency pendulum isolator” Journal of Structural Engineering and Mechanics, 34, 61-84.

•

Soong, T. T., (1990) “ Active Structural Control: Theory and Practice” Longman Scientific & Technical .

•

Soong, T. T., Costantinou, M. C., (1994) “ Passive And Active Structural Vibration Control in Civil Engineering ” Springer Verlag Wien – New-York . •

Spencer, B. F. Jr., Nagrajaiah, S., (2003) “ State of the Art of Structural Control” Springer Verlag Wien – New-York .

•

Active Isolation

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