tokyo institute of technology, yoshihiro yamazaki 16th u.s

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Tokyo Institute of Technology, Yoshihiro Yamazaki

Study on Dynamic Behavior of Wooden Horizontal Hybrid Structure Involving Stiff Cores

Study on Dynamic Behavior ofWooden Horizontal Hybrid Structure

Involving Stiff Cores

Yoshihiro YAMAZAKI （Assist. Prof., Tokyo Institute of Technology, Japan）

Hiroyasu SAKATA （Prof., Tokyo Institute of Technology, Japan）

16th U.S.-JAPAN-N.Z. WORKSHOP ON IMPROVEMENT OFSTRUCTURAL ENGINEERING AND RESILIENCYJune 27-29, 2016, Todaiji Temple Cultural Center, Nara, Japan



1. Background

Vertical hybrid structure Horizontal hybrid structure

RC

Wood

RCWood

RCWood

WoodDesign hand book

Horizontal hybrid structure

RCWood

RCWood

WoodHorizontal hybrid structure

RCWood

RCWood

WoodVertical hybrid structure

RC

Wood

Vertical hybrid structure

RC

Wood

• Wood structures have been built mainly as small detached houses so far. But large buildings are also expected to be built by wood because of environmental issue.

• Hybrid structure has advantages to enhance the seismic resistance.

• Design handbook for wood hybrid structures were published. However, horizontal hybrid structures are NOTcovered.

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2. A Prototype of Horizontal Hybrid Structure of Wood and RC

1680

00

8000 8000 8000 8000 8000 80008000 8000 80008000 8000 80008000 8000 2400024000 48000

112000

8000

8000

Wood Core(RC)

Wood Core(RC)

Wood

X1 X2 X3 X4 X5 X6 X7 X8 X9 X10 X11 X12 X13 X14 X15

Y1

Y2

Y3

Architectural Institute of Japan (2012), “Technical Issues and resolutions of Large Wood Building” (in Japanese), Material of AIJ annual meeting 2012

3-story school buildingFloor area＝5,532m2

Height＝13.4m

Wood : Glued-laminated timber's framing and plywood sheathing walls and floor diaphragms

RC core : RC frame with shear walls

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Wood part dominant 1st mode Wood part dominant 2nd mode

Core part dominant 1st mode Core part dominant 2nd mode

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3. Characteristics of Seismic Response Connectionforce

Connectionforce

Wood Core

Force distributionForce distribution

Force transmission

Force transmission

・ Difference of weight and stiffness between wood parts and RC parts

・ Deformation of floor diaphragm in wood parts

Span dir.

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4. Objective

The seismic performance of horizontal hybrid structure is demonstrated through shaking table test of scaled specimens.

Then simplified modeling method by two-dimensional continuous model is introduced, and the applicability is discussed.

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Core part(steel jig)

Weights (19kN)

5. Setup of Shaking Table Test

One-sided core

- Wood part

→ One third scaled model

- Core part

→ Steel jigs

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Plywood (t=9mm)Nail (d=2.1mm, L=32mm) @100mm

Plywood (t=12mm)Nail (d=2.1mm, L=32mm) @150mm(No.1,3)/50mm(No.2)

(A) (C)

(B)

Transverse dir. (X1～X3)

910

1213 1213 12131820

Post(60x60mm)：Spruce

Beam(60x150mm)：Scotch pine

910

910

Longitudinal dir. (Y1, Y2)

(*) Bolts (Φ=6mm)

6. Specimen

Washer24x24mm

(A)

Steel bar 16mm

Base plate with shear ring(Φ27.2, t=2.3)

(B)

(C)Washer24x24mm

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X4

X3

X2

X1 2

2

2@150mm

Core

2

2

2@50mm

4

0

0@150mm

Core CoreNails’ pitch

The number of walls

No.1No.1 No.2No.2 No.3No.3

7. List of Specimens

Parameters are・ arrangement of shear walls・ nails’ pitch of floor diaphragm (in-plane stiffness)

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Period (sec)

Pse

udo

acc.

(cm

/sec

2 )

Target(5%damping, PGA=0.4g)

Natural period of specimens

8. Input motion Original

Scaled

x 1/√3

Time (sec)

Time (sec)

Acc

.(cm

/sec

2 )A

cc.(

cm/s

ec2 )

Motion PGA

1 WN 0.05g

2 EQ 0.1g

3 WN 0.05g

4 EQ 0.2g

5 WN 0.05g

6 EQ 0.4g

7 WN 0.05g

8 EQ 0.6g

9 WN 0.05g

10 EQ 0.8g

11 WN 0.05g

WN : White NoiseEQ : Artificial Earthquake

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Specimen No.1, PGA=0.8g, Time scale x √3 (original scale)



2

Core

2 2 2 2 2 4 0 0

X3X2X1 CoreX3X2X1 CoreX3X2X1

Flexible diaphragm Stiff diaphragm Flexible diaphragm

9. Maximum Displacement Distribution

No.1No.1 No.2No.2 No.3No.30.4g0.6g0.8g

29.6 20.6 31.8

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Floor diaphragmShear wall

1/120rad

-1/240rad

-1/120rad

1/240rad

No.1No.1

No.2No.2

No.3No.3

No wallNo wall No wallNo wall

10. Force-Deform. Relation of Each Element

PGA0.4g

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1/120rad

-1/240rad-1/120rad

1/240rad

1/60rad 1/60rad 1/60rad1/60rad

PGA0.8g



11. Seismic Force RatioShared by Wood part and Core Part

3F

2F

1F

0 0.5 11

2

3

0 0.5 11

2

3

0 0.5 11

2

3

X1 X2 X3

X1 X2 X3 X1

Wood Core

Floor Floor FloorNo.1No.1 No.2No.2 No.3No.3

Ratio Ratio Ratio

Wood CoreWood Core

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0 0.5 11

2

3

0 0.5 11

2

3

0 0.5 11

2

3X1 X2 X3

X1 X2 X3 X1

PGA0.4gPGA0.4g

PGA0.8gPGA0.8g

Wood CoreWood CoreWood Core

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x

y

Uniform shear panel(Two-dimensional)

12. Idea of Modeling Method

Uniform shear bar(One-dimensional)

x

Discretizedmodel

(Lumped mass)

Continuousmodel

Useful to obtain

・fundamental period・seismic force distr.

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Core

Ground



2

2

2

2

2

2

y

uG

x

uG

t

uyx

Equation of

wave motion

H

yn

L

xmyx

fmn 2

)12(sin

2

)12(sin,

Get eigen function considering boundary condition

yx

fmn

G

H

nG

L

m22

2

)12(

2

)12(

x

yu(x,y)

y = H

y = 0

x = 0

x = Lf

0),0( yu

0)0,( xu

0),(

x

yLu f

0),(

y

Hxu

13. Equation of Motion

Please seeYoshihiro Yamazaki and Hiroyasu Sakata, 2016, "Simplified Modeling Method and Seismic Force Evaluation of Building Structures Involving Stiff Cores: Study on dynamic behavior of wooden horizontal hybrid structure Part1(in Japanese)", Journal of structural and construction engineering, Architectural Institute of Japan, No.720, pp.291-301

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Pi Qi

N

ijjW

Floor

No.1No.2No.3

A'i (Only 1st mode)A'i (All modes)Ai (Conventional)

Test results Analysis results

Vertical shear coefficient

N

ijjW

Seismic force

Weight abovei-th floor

)2( iAi = Qi / A1

14. Comparison of Vertical Shear Coefficient

)2/sin(

)2/sin(1

23

231

1

11

i

i

ii

i

iA

11/

/

,

11,

NNf

NNfN Wk

WkR 2

2

HG

LG

x

fy

)(5.0

)(5.0

1

1

1

1

1

1

1

NiWRWWRW

NiWRWWRWW

NN

N

jjNN

NN

N

jjNN

N

ijj

i

(Combination of all modes)

(Only the 1st mode)

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1) 50 to 70% of seismic force acting on wood part was transmitted to core through floor diaphragms. The original intension of horizontal hybrid structure was realized. Therefore not only shear walls but floor diaphragms clearly contribute to seismic force resistance capacity.

2) Applicability of continuous model was discussed. It could improve accuracy of the vertical shear coefficient distribution compared to the conventional formula. The method can be applied to evaluate other dynamic properties.

15. Conclusions18/20

Seismic behavior of wooden horizontal hybrid structure involving stiff cores was discussed.

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Acknowledgment

This work was supported by JSPS KAKENHI Grant Number JP26709039(Grant-in-Aid for Young Scientists (A)) and THE KAJIMA FOUNDATION.

The shaking table test was conducted in Technology Development Division, Fujita corporation.

We would like to express our gratitude to them.

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Thank you for your kind attention

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tokyo institute of technology, yoshihiro yamazaki 16th u.s

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