Yeong-Jong Moon Dept. of Civil and Environmental Engineering KAIST, Korea

Yeong-Jong MoonYeong-Jong Moon

Dept. of Civil and Environmental Engineering

KAIST, Korea

The 17th Engineering Mechanics Conference of ASCEUniversity of Delaware, Newark, DEJune 13 - 16, 2004

Application of Some MR Damper-based Control Systems for Seismic Protection of

Benchmark Base Isolated Building

Structural Dynamics & Vibration Control Lab., KAIST, KoreaStructural Dynamics & Vibration Control Lab., KAIST, Korea 22

Contents

Introduction


MR Damper-based Control System

Control Algorithms

Numerical Simulation Results

Conclusions


Introduction

Base isolation systems, such as elastomeric, friction, and lead-rubber bearing systems, have been accepted as an effective means for seismic protection of building structures.

Base isolation systems can reduce inter-story drifts and floor accelerations, whereas base displacements in those systems may be increased. expensive loss of space for seismic gap

Hybrid-type base isolation systems employing additional active control devices have been studied to limit base drift.


Because of its adaptability and reliability, an MR damper- based hybrid-type base isolation system could solve the large base drift problem of the passive-type base isolation system.

To systematically compare the effectiveness of control systems for base isolated buildings, the benchmark study developed by Narasimhan et al. (2003) based on input from the ASCE structural control committee.

In the benchmark problem, three different kinds of base isolation systems, such as linear elastomeric with low damping, frictional systems, and bilinear or nonlinear elastomeric systems, are considered.


To verify the effectiveness of the MR damper-based control systems considering some control algorithms, such as modified clipped-optimal control, maximum energy dissipation, and the modulated homogeneous friction algorithms, for seismic protection of base isolation system.

Objective of This Study


Benchmark Structure

an eight-story base isolated steel-braced framed building

width: 82.4m and 54.3m

similar to existing buildings in LA, California



Base Isolation Systems Considered

Linear elastomeric isolation system: 92 low damping elastomeric bearings

Nonlinear isolation system:

61 friction pendulum bearings and 31 linear elastomeric bearings

Supplemental active or semiactive control devices:

16 active or semiactive control devices at the isolation level

(8 in X- and 8 in Y-direction)


Control Diagram for MR Damper-based System

MR Damper-based Control System

Controller(Control Algorithm)

gx

bb xx ,

v

MR Damper

MRf

my

eyBase Isolated

Building Structure


Original Clipped-Optimal Control Algorithm

Control Algorithms

OptimalControl(LQG)

gx

bb xx ,

v

MR Damper

MRf

my

eyBase Isolated

Building Structure

MRMRc fffHVv max

Clipped Algorithm(0 or Vmax)

cf


Modified Clipped-Optimal Control Algorithms

OptimalControl(LQG)

gx

bb xx ,

v

MR Damper

MRf

my

eyBase Isolated

Building Structure

Clipped Algorithm

(Vc)

cf

MRMRcc fffHVv

max

maxmaxmax

,0

,)(

fffor

ffforffVV

c

ccc

Modified version proposed by Yoshida and Dyke (2004)


OptimalControl(LQG)

gx

bb xx ,

v

MR Damper

MRf

my

eyBase Isolated

Building Structure

Clipped Algorithm

(Vc)

cf

MRMRcc fffHVv

Another modified version proposed in this study

MRc

MRcMRcc ffforV

fffforffVV

max

maxmax ,)(


Maximum Energy Dissipation Algorithm

This algorithm considers a Lyapunov function that represents the relative energy in the structure (Jansen and Dyke, 2000). gx

bb xx ,

v

MR Damper

MRf

my

eyBase Isolated

Building Structure


MRb fxHVv max


Modulated Homogeneous Friction Algorithm

This algorithm originally developed for use with variable friction devices was modified for MR dampers (Jansen and Dyke, 2000). gx

bb xx ,

v

MR Damper

MRf

my

eyBase Isolated

Building Structure


MRn ffHVv max)( stgf nn

, in which , the most recent local extrema in the deformation of the MR damper )( st }0)(:0{min xtxs


Numerical Simulation Results

Control Algorithms Considered - Original modified clipped-optimal for linear system (OCO) - Skyhook control for nonlinear system (SHC)

- Modified clipped-optimal by Yoshida and Dyke (MCO-1) - Modified clipped-optimal proposed herein (MCO-2) - Maximum energy dissipation (MED) - Modulated homogeneous friction (MHF)

Base Isolation Systems Considered - Linear elastomeric isolation system - Nonlinear friction isolation system


Evaluation Criteria (Narasimhan et al., 2003)

- J1: normalized peak base shear

- J2: normalized peak structure shear

- J3: normalized peak base displ. or isolator deformation

- J4: normalized peak inter-story drift

- J5: normalized peak absolute floor acceleration

- J6: normalized peak force generated by all control devices

- J7: normalized RMS base displacement

- J8: normalized RMS absolute floor acceleration

- J9: normalized total energy absorbed by all control devices

* In this study, the results of each algorithm are normalized by those of OCO in linear case and SHC in nonlinear case.


Earthquakes Used (Narasimhan et al., 2003)

Both the fault-normal (FN) and the fault-parallel (FP) components of

- Newhall record in Northridge earthquake

- Sylmar record in Northridge earthquake

- El Centro record in Imperial Valley earthquake

- Rinaldi record in Northridge earthquake

- Kobe record in Hogoken Nanbu earthquake

- Jiji068 record in Jiji earthquake

- Erzinkan record in Erzinkan earthquake


Linear Elastomeric Isolation System

Earthquakes J1 J2 J3 J4 J5 J6 J7 J8 J9

NewhallFP:X FN:Y 1.06 0.97 1.27 1.09 0.97 0.95 1.62 0.76 0.67

FP:Y FN:X 1.00 0.98 1.26 1.08 0.72 0.91 1.90 0.72 0.67

SlymarFP:X FN:Y 0.99 1.07 1.09 1.11 1.08 1.40 1.19 0.88 0.84

FP:Y FN:X 1.46 1.15 1.05 1.14 2.40 2.33 1.15 0.85 0.89

El CentroFP:X FN:Y 0.89 1.05 2.30 1.04 0.37 0.29 3.25 0.52 0.63

FP:Y FN:X 0.89 1.09 2.40 1.21 0.41 0.26 3.42 0.58 0.61

RinaldiFP:X FN:Y 0.91 1.03 1.21 1.03 0.81 0.97 1.32 0.87 0.76

FP:Y FN:X 0.85 1.01 0.98 1.05 0.75 0.97 1.22 0.68 0.77

KobeFP:X FN:Y 0.91 0.93 1.35 1.11 0.88 1.11 2.19 0.81 0.70

FP:Y FN:X 0.99 1.06 1.38 1.28 0.79 1.21 2.42 0.89 0.63

JijiFP:X FN:Y 1.18 1.06 1.04 1.10 1.81 2.44 1.22 0.99 0.86

FP:Y FN:X 1.30 1.02 1.04 1.04 2.33 3.62 1.31 1.06 0.88

ErzinkanFP:X FN:Y 0.99 0.95 1.17 0.90 0.97 1.01 1.28 0.85 0.76

FP:Y FN:X 0.91 0.84 1.16 0.96 1.00 1.31 1.26 0.71 0.79

Control performance of MCO-1 normalized by OCO


Discussion

- All the peak floor accelerations (J5) are reduced up to 63% except of the Sylmar and Jiji cases while maintaining the similar level of the peak inter-story drifts (J4) (a 28% increase ~ a 10% decrease).

- All the peak isolator deformations (J3) in MCO-1 are larger than those in OCO (a 4%~140% increase) except of the Rinaldi case (a 2% decrease).

- In the El Centro case, MCO-1 significantly reduces the peak floor acceleration (J5), whereas is drastically increases the peak isolator deformation (J3) .


Control performance of MCO-2 normalized by OCOEarthquakes J1 J2 J3 J4 J5 J6 J7 J8 J9

NewhallFP:X FN:Y 1.01 0.95 1.03 1.00 1.02 0.98 1.09 0.86 0.94

FP:Y FN:X 0.90 0.88 1.04 1.09 0.73 0.97 1.32 0.91 0.94

SlymarFP:X FN:Y 1.01 1.02 1.05 1.07 0.96 1.00 1.02 0.98 0.98

FP:Y FN:X 0.92 0.92 1.10 1.00 0.92 0.94 1.12 0.80 0.98

El CentroFP:X FN:Y 1.17 1.19 1.34 1.15 0.97 0.86 1.48 0.78 0.90

FP:Y FN:X 1.22 1.24 1.96 1.47 1.18 0.83 1.72 0.91 0.93

RinaldiFP:X FN:Y 1.05 1.01 1.03 0.95 1.07 0.97 1.03 0.97 0.97

FP:Y FN:X 0.97 1.01 0.91 0.97 1.01 0.97 0.84 0.68 0.97

KobeFP:X FN:Y 1.00 1.02 1.00 1.08 0.98 1.01 1.26 0.94 0.95

FP:Y FN:X 1.15 1.15 1.04 1.31 0.95 1.05 1.64 1.08 0.90

JijiFP:X FN:Y 0.99 1.00 0.99 0.99 0.97 1.01 1.01 0.97 0.98

FP:Y FN:X 0.90 0.91 0.99 0.92 0.86 0.99 1.05 0.82 0.95

ErzinkanFP:X FN:Y 0.98 0.95 0.99 0.91 0.98 1.01 1.01 0.97 0.98

FP:Y FN:X 0.90 0.83 1.08 0.95 0.89 0.96 0.92 0.76 0.98


Discussion

- The overall performance of MCO-2 is similar to that of MCO-1.

- All the peak floor accelerations (J5) are reduced up to 27% except of the El Centro and Rinaldi cases.

- Increases in J5 of MCO-2 are not large compare with those of MCO-1 (e.g., an 18% increase under El Centro in MCO-2; a 140% increase under Sylmar in MCO-1).

- It is verified that MCO-2 could be the more reliable control algorithm under various ground motions.



NewhallFP:X FN:Y 0.91 0.93 1.25 0.97 0.73 0.95 1.44 0.82 0.80

FP:Y FN:X 0.93 0.84 1.18 0.93 0.89 0.97 1.68 0.92 0.81

SlymarFP:X FN:Y 0.97 1.04 1.15 0.97 0.82 0.93 1.33 0.93 0.80

FP:Y FN:X 0.88 0.89 0.95 0.98 0.89 0.98 1.04 0.76 0.86

El CentroFP:X FN:Y 1.01 1.04 1.36 1.00 0.89 0.95 1.72 0.83 0.86

FP:Y FN:X 0.87 1.10 1.96 1.22 1.10 1.15 2.39 0.98 0.85

RinaldiFP:X FN:Y 0.92 1.04 1.05 1.04 0.82 0.93 1.32 0.97 0.82

FP:Y FN:X 0.81 0.97 1.03 1.03 0.73 0.97 1.03 0.68 0.79

KobeFP:X FN:Y 0.77 0.89 1.05 0.98 0.78 1.28 1.24 0.93 0.91

FP:Y FN:X 0.93 0.98 1.04 1.14 0.70 1.27 2.01 1.17 0.86

JijiFP:X FN:Y 1.06 1.12 1.20 1.11 0.90 0.75 1.28 1.02 0.76

FP:Y FN:X 0.98 1.01 1.16 1.03 0.99 0.95 1.29 0.85 0.77

ErzinkanFP:X FN:Y 0.91 0.95 1.04 0.88 0.78 0.97 1.30 0.93 0.76

FP:Y FN:X 0.89 0.81 1.13 0.90 0.98 0.92 1.02 0.68 0.84

Control performance of MHF normalized by OCO


Discussion

- The control performance of MHF is quite good.

- All the peak floor accelerations (J5) are reduced by 30% ~1% except of the El Centro case (a 10% increase).

- All the peak inter-story drifts (J4) are within the reasonable ranges (a 12% decrease ~ a 22% increase).

- MHF could be considered as one of the promising control algorithms for base isolated buildings employing MR dampers in the linear elastomeric case.



NewhallFP:X FN:Y 1.16 1.11 1.19 1.00 1.12 0.72 1.17 0.88 0.77

FP:Y FN:X 1.05 1.19 1.15 1.20 0.99 0.83 1.04 0.98 0.84

SlymarFP:X FN:Y 1.18 1.23 1.19 1.06 0.85 0.68 1.26 0.88 0.74

FP:Y FN:X 1.16 1.20 1.20 1.36 0.91 0.77 1.37 0.95 0.73

El CentroFP:X FN:Y 0.97 0.84 1.24 0.89 0.90 0.85 1.15 0.84 0.70

FP:Y FN:X 0.85 0.93 0.97 1.01 0.97 0.98 0.98 0.85 0.70

RinaldiFP:X FN:Y 1.12 1.04 1.07 0.92 0.71 0.76 1.14 0.85 0.75

FP:Y FN:X 1.10 1.08 1.07 0.87 0.82 0.66 1.15 0.84 0.75

KobeFP:X FN:Y 1.12 0.90 1.39 0.96 0.91 0.69 1.17 0.85 0.56

FP:Y FN:X 1.11 0.96 1.42 1.04 0.91 0.68 1.16 0.87 0.58

JijiFP:X FN:Y 1.16 1.14 1.27 1.03 0.86 0.86 1.14 0.98 0.88

FP:Y FN:X 1.14 1.10 1.25 1.06 1.06 0.87 1.09 1.02 0.88

ErzinkanFP:X FN:Y 1.06 1.06 1.26 0.96 0.88 0.88 1.38 0.88 0.66

FP:Y FN:X 1.06 1.18 1.29 1.03 0.90 0.79 1.45 0.95 0.71

Nonlinear Friction Isolation System

Control performance of MHF normalized by SHC


Discussion

- The control performance of MHF is quite good in the nonlinear friction case as well.

- All the peak floor accelerations (J5) are reduced by 29% ~1% except of the Newhall and Jiji cases (12% and 6% increases, respectively).

- All the peak inter-story drifts (J4) are within the reasonable ranges (a 13% decrease ~ a 36% increase).

- MHF could be considered as an appropriate control algorithm for base isolated buildings employing MR dampers in the nonlinear friction case.


Conclusions

Some control algorithms, such as MCOs, MED, and MHF, are considered to verify the effectiveness of MR damper-based control systems for seismic protection of a base isolated building.

Most of the control algorithms considered could be beneficial in reducing seismic responses of a benchmark base isolated building.

The modulated homogeneous friction algorithm could be considered as one promising candidate for the nonlinear as well as the linear benchmark base isolated systems.


Thank you for your attention!

Yeong-Jong Moon Dept. of Civil and Environmental Engineering KAIST, Korea

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Transcript of Yeong-Jong Moon Dept. of Civil and Environmental Engineering KAIST, Korea