31_KURAUCHI

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Nobuyuki KURAUCHI

AZUSA SEKKEI Co.,Ltd.

Osaka , Japan

14th U.S.-Japan Workshop on Improvement of

Structural Design and Construction Practices

14th U.S.-Japan Workshop on Improvement of

Structural Design and Construction Practices

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Why was needed the seismic retrofit ?

14th U.S.-Japan Workshop on Improvement of Structural Design and Construction Practices

December, 2012

Improvement of the seismic retrofit of this buildingwas needed, the controller escaped by intense fear

in the Great East Japan Earthquake.

The important facility as the main gate of Japan. Preparation for Tokyo metropolitan earthquake

which may happen from now on.

Why was needed the seismic retrofit ?

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Why adopted the damping structure?


December, 2012

The reinforcement work must be donewhile the building is being used.

No change was allowed concerningthe main electric cables and building equipment.

The cost of the seismic retrofit must be kept inthe limited budget.

Why adopted the damping structure?

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Existing Building Outline-1Existing Building Outline-1


December, 2012

SITE

Airport Administration Building

Control TowerConnecting bridge

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Existing Building Outline-2Existing Building Outline-2


December, 2012

Location : Chiba , Japan

Building area : 241.43Total floor area : 1778.26Standard floor area : 169.74(13.16 sq. meters)Number of floors : L21Height of building : 87.3Structure : S , partly SRC or RC

Foundation : pile

S

SRC,RC

87.3

m

6.5813.16m

X1X

Y

6.58

X2 X3

Y1

Y2

Y3

Y4

m

4

4

48

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Structural Planning-Structural design of Existing BuildingStructural Planning-Structural design of Existing Building


December, 2012

Frame Form : S , Moment Frame with braces (L2~ )

SRC , Box-frame construction(L1)

Main Frame : Column section is a shape of 550mm-box and

a shape of 450mm-diameter-pipe.

Maximum depth of H-Beam is 700mm.

Maximum depth of H-Brace is 400mm.

Thickness of bearing wall is 900mm.

Foundation : Mat slab form(Thickness is 5m)

Cast-in-place concrete pile(Diameter is 1.5m)

Material Strength : Tensile strength of Steel is 490N/mm2 .

Compressive strength of concrete is 21N/mm2.

Tuned liquid damper(TLD)is installed on the L15

Situation of installed TLD (L15)

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Structural Planning-Application design of viscous dampersStructural Planning-Application design of viscous dampers


December, 2012

:Viscous Damper

:Brace

:Reinforcement Beam

Fig. Beam plan

Fig. Section plan for disposition of viscous dampers

Y1,4

X1 X2 X3

Y1

Y2

Y3

Y4

Y2,3 X2

X

Y

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Structural Planning-type-1 of viscous dampersStructural Planning-type-1 of viscous dampers


December, 2012

[leaned arrangement type(Y2 L2-3)]

For example

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Structural Planning-type-2 of viscous dampersStructural Planning-type-2 of viscous dampers


December, 2012

[Amplification mechanism type(X2 L9-11)]

For example of installing out-frame

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Dynamic characteristics of existing buildingDynamic characteristics of existing building


December, 2012

Fig. Seismographs arrangement

Fig. Free vibration of horizontal motion

Table. 1st natural period and damping coefficient

VFR Room

1st(1992)

2nd(1992)

3rd(1993)

4th(1994)

5th(1998)

6th(2004)

Natural Dampingcoefficient(%)period(s)

Before installing TLD

After installing TLD

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Level-2 KOBE Phase(Foundation position)

-500

0

500

0 10 20 30 40 50 60

Accelerat

ion(cm/s2)

Level-2 KOBE Phase(Foundation position)

Level-2 HACHINOHE Phase(Foundation position)

-500

0

500

0 10 20 30 40 50 60

Second(s)

Accele

ration(cm/s2)

Level-2 HACHINOHE Phase(Foundation position)

1

10

100

1000

0.1 1 10Period(s)

VelocityRe

sponseSpectra(cm/s

0.1cm0.05cm

1.0cm

10.0cm

1gal10

gal

100ga

l

1000g

al

500g

al

1000

0gal

100cm

1000cm

Structural Design Criteria-

Selection of Input Earthquake Motion


Selection of Input Earthquake Motion


December, 2012

Level-1 three kinds of phase

Level-2 three kinds of phase

Maximum-316.58(cm/s2)

Maximum-387.82(cm/s2)

(h=5%)

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Structural design criteria of seismic retrofit building


Structural design criteria of seismic retrofit building


December, 2012

Table. Structural Design Criteria of seismic retrofit building

* The top of building partly cannot meet the design criteria of Inter-story drift angle.

Therefore, total inter-story drift is divided into bending deformation and shear deformation

and, paying attention to shear deformation, breakage and fall of the exterior are checked

Figure . Outline of Inter-Story Drift Angle

Total inter-story drift ; rotational moment of floor horizontal displacement of floor

s

b

A

B

C

D

A

B

C

D

AB

CD

Bending deformation ; b shear deformation ; s

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Structural Modeling and Analysis Method(1)Structural Modeling and Analysis Method(1)


December, 2012

Fig. Analysis model

1) Boundary condition: bottom of column installed on the L1 is Pin support2) Node has six degrees of freedom, while node installed on the slab has three degrees of freedom

3) restoring force characteristics of structural element

Beam bending: end of member has rotational spring (Fig. a)

Restoring force characteristics is Bi-linear Type

Shear : center of member has shear spring (Fig. b)Restoring force characteristics is Bi-linear Type

Brace : Axial direction spring (Fig c)

Restoring force characteristics is Bi-linear Type

Column, wall : fiber (MS) model (Fig. d)

Fig d. Fiber modelFig c. Axial direction spring

Fig b. Beam shear model

Fig a. Beam bending model

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800kN Viscous damper(Amplication mechanism type)

0

200

400

600

800

1000

0 20 40 60 80Velocitycm/s

Dam

pingforcekN

Maximum force

2000kN Viscous damperLeaned arrangement type

0

500

1000

1500

2000

2500

0 5 10 15 20 25 30Velocitycm/s

DampingforcekN)

Maximum force

Structural Modeling and Analysis Method(2)Structural Modeling and Analysis Method(2)


December, 2012

Inter Node

K C

Viscous damper : Maxwell Model.(Fig e)

)Type-1 (Leaned Arrangement Type)Damping coefficient ; C1 , C2 =750, 14.4[kNsec/cm]

Stiffness coefficient ; K=5800[kN /cm], constant value

)Type-2 (Amplification Mechanism Type)

Damping coefficient ; C1 , C2 =120, 4.0[kNsec/cm]

Stiffness coefficient ; K=2352[kN /cm], constant value

Axial stiffness of brace is slip model in consideration of a displacement loss

Fig e. Maxwell Model

Fig . Nonlinear curve (type-1) Fig . Nonlinear curve (type-2)4) Damping; Structural Damping is type of internal viscous damping of initial stiffness coefficient and

first mode damping ration(=h1) is =0.01.

5) Stiffness;

Shear deformation for junction of the intersection portions of column and beam must be taken into consideration.

The rigidity of beam bending must be increased by slab. (=1.3:single-sided slab, =1.5:both-sides slab)

Product Error :10%Product Error :10%

C1

C2

C1

C2

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Fig. Damper disposition proposal of Y-direction

Fig. Damper disposition proposal of X-direction

Analysis Result-

Comparison of Maximum Response based on damper disposition

Analysis Result-

Comparison of Maximum Response based on damper disposition


December, 2012

Maximum inter-story drift angle

01234567

89

101112131415161718192021

0.000 0.005 0.010 0.015

Inter-story drift angle(rad)

Floor

Case-1

Case-2


0123456789

10

1112131415161718192021

0.000 0.005 0.010 0.015

Inter-story drift angle(rad)

Floor

Case-1

Case-2

Case-3

Y1,4

[CASE-1]

Y2,3

[CASE-2] [CASE-3]

[CASE-2][CASE-1]

Y1,4 Y2,3 Y1,4 Y2,3

X2 X1 X3 X2 X1 X3

X-direction 1.31 1.41 1.31 1.31

Y-direction 1.30 1.30 1.30

Case-3ExsitingModel

Case-1 Case-2

Fig. damper disposition

Table . 1st Natural period(s)

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Analysis Result-Effect of viscous dampers(1)Analysis Result-Effect of viscous dampers(1)


December, 2012


0

1

2

34

5

6

78

9

1011

12

13

14

15

16

1718

19

20

21

0.000 0.005 0.010 0.015 0.020

Inter-story drift anglerad

Floor

Existing model

Retrofit model

Maximum story share force

01

2

3

4

5

6

78

9

10

11

12

13

14

15

16

17

18

19

20

21

0 10000 20000 30000

story share forcekN

Floor

Existing model

Retrofit model

Maximum acceleration response

01

2

3

4

5

6

78

9

10

11

12

13

14

15

16

17

18

19

20

21

0 1000 2000 3000

Acceleration responsecm/s2

Floor

Existing model

Retrofit model

Fig. Maximum Response of X-direction

Average; about 38%

Average; about 35%

Average; about 25%

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December, 2012


0

1

2

3

4

5

6

78

9

10

11

12

13

1415

16

17

18

19

20

21

0.000 0.005 0.010 0.015 0.020

Inter-story drift anglerad

Floor

Existing model

Retrofit model

Maximum story share force

01

2

34

56

78

910

1112

1314

1516

1718

1920

21

0 10000 20000 30000

story share forcekN

Floor

Existing model

Retrofit model

Maximum acceleration response

01

2

3

4

5

6

78

9

10

11

12

13

14

15

16

17

18

19

20

21

0 1000 2000 3000

Acceleration responsecm/s2

Floor

Existing model

Retrofit model

Fig. Maximum Response of Y-direction

Average; about 9% Average; about 7%Average; about 7%

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December, 2012

Y-Direction

-2000.00

-1500.00-1000.00

-500.00

0.00

500.00

1000.00

1500.00

2000.00

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00

Second(s)

flooracceleration

response(cm/s2)

Existing model

Retrofit model

X-Direction

-2000.00

-1500.00

-1000.00-500.00

0.00

500.00

1000.00

1500.00

2000.00

0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00 80.00

Second(s)

flo

oracceleration

re

sponse(cm/s2) Existing model

Retrofit model

Y-Direction

-500.00

0.00

500.00

60.00 70.00 80.00Second(s)

flooracceleration

response(cm/s2)

Existing model

Retrofit model

X-Direction

-500.00

0.00

500.00

60.00 70.00 80.00Second(s)

flooracceleration

res

ponse(cm/s2) Existing model

Retrofit model

Fig. Time History of Response acceleration (X-direction / L20)

Fig. Time History of Response acceleration (Y-direction / L20)

The highest response; about 18%

The highest response; about 5.5%

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ConclusionsConclusions


December, 2012

Earthquake-proof performance was improved with the proposedseismic retrofit using viscous dampers, in compliance with

structural design criteria.

After this reinforcement work ended, we are scheduled to

experiment on dynamic characteristics based on microtremor

measure and free vibration test.

31_KURAUCHI

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