wcte12 - session 36 - connections 10.pdf

8/12/2019 WCTE12 - Session 36 - Connections 10.pdf

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World Conference on Timber Engineering

Auckland New Zealand15 - 19 July 2012

Development of The High-strength and High-ductility Timber

Framed Joints using Drift Pins and Fiber Reinforced Plastics

Shinya Matsumoto1, Takaaki Ohkubo2, Yasuaki Watanabe3, Etsuo Kajita4

ABSTRACT:The joints are very important structural element in timber framed structures. The purpose of this study is

to develop the high-strength and high-ductility beam-column joint for timber structure. In this study, steel plate

fastened with drift pins and paste the ultraviolet-ray hardening Fiber Reinforced Plastics (FRP) on the surface of the

member section. The wood is the anisotropic material of which the strength characteristic greatly differs according to

the direction of the fiber. The strength of the fiber direction is high, but the strength of the fiber orthogonal direction is

low. Also, the splitting failure is caused in the fiber orthogonal direction, and there is a case in which strength and

toughness extremely lower. It is necessary to consider the weak point of such woody material for the case in which thewood is used as a structural element for timber framed structure. It is very important to be ensured the earthquake-proof

safety of the building, and prevent a building collapse for the great earthquake. This study reinforces weak point on the

strength of woody material by using the ultraviolet-ray hardening FRP. Then, timber framed joint of the high-strength

and high ductility is developed as a structural element. In this study, the basic experimental tests which the degradationaccelerated test for temperature, outdoor weather tests are carried out to grasps durability performance. Then, the

verification experiment is carried out for the joint element specimens of the large section wood.

KEYWORDS:Composite material, Column beam joints, Ultravioletrayed-hardening, FRP

1 INTRODUCTION 123The wood is the anisotropic material of which the

strength characteristic greatly differs for the direction of

the fiber. Though the strength of the fiber direction is

high, the strength is low for the fiber orthogonal

direction. Also, the splitting failure is caused in the

fiber orthogonal direction, and there is a case in which

strength and toughness extremely lower. It is necessary

to consider the weak point of such woody material for

the case in which the wood is used as a structural

element for timber framed structure.

Recently, the development of engineered wood such as

the structural glued laminated wood advances. Themarket is supplied with the lumbering of which the

quality is high as an industrial product. The technology

which artificially controls the material dispersion is

1Shinya Matsumoto, Department of Architecture, Faculty of

Engineering, Hiroshima University, 1-4-1, Kagamiyama,

Higashi-Hiroshima,739-8527, Japan. Email:

[email protected] ohkubo, Department of Architecture, Faculty of

Engineering, Hiroshima University, 1-4-1, Kagamiyama,

Higashi-Hiroshima,739-8527, Japan3

Yasuaki Watanabe, Asahi-Kasei Geotech, Tokyo, Japan4Etsuo Kajita, Asahi-Kasei Geotech, Tokyo, Japan

widely used. However, they also worry about the

possibility of causing fracture event in the design by thelarge earthquakes etc. It is very important to be ensured

the earthquake-proof safety of the building, and prevent

a building collapse for the great earthquake. This study

reinforces weak point on the strength of woody material

by using the ultraviolet-ray hardening FRP. It is a basic

research with the aim of further upgrading of past

earthquake-proof technology.

This study reinforces weak point on the strength of

woody material by using the ultraviolet-ray hardening

FRP. Then, timber framed joint of the high-strength and

high ductility is developed as a structural element. In

this study, the basic experimental tests which the

degradation accelerated test for temperature, outdoor

weather tests are carried out to grasps durability

performance. Then, the verification experiment is

carried out for the joint element specimens of the large

section wood.

2 Outline of the researchIn the reinforcement of glass fiber (high intensity) or

vinylon fiber (high deformability), FRP sheet handled in

this study are epoxy acrylate plastic and ultravioletrayed-

hardening FRP sheet which impregnated with the

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ultraviolet curing initiator. This FRP sheet hardens by

the polymerization reaction, when the irradiation ofultraviolet ray (315-400nm wavelength) is received.

This FRP sheet is carried in the condition that the

ultraviolet ray was shielded in the construction field.

And the attachment work was carried out for the fixedplace. It is possible that this FRP sheet finishes the

construction in the short period by forcing andirradiating ultraviolet ray ultraviolet fluorescence light

(black light). The field processing in proportion to shape

and dimension of the reinforcement position can be

easily carried out in order to carry out the construction in

the condition of the soft sheet before the hardening,

means of reinforcement work this FRP sheet. Thisconstruction method using this FRP sheet is possible to

simply process in construction field because the

construction is carried out in the soft condition before

the hardening.

In addition, it is an easy point by the attachment workby this sheet tearing off the bright film which covers thesurface, and it is excellent in the workability. The cross

section schema and appearance of the ultravioletrayed-

hardening FRP sheet are shown in Figure 1.

Figure 1: Ultravioletrayed-hardening FRP sheet crosssection schema and appearance.

3 Durability performance testIn this research, the durability performance test is

carried out for the purpose of verifying the weather

resistance in bonding this ultravioletrayed-hardening

FRP to the wood.

In this test, the artificial temperature cycle was

determined like the Figure 2 used by the temperaturechamber. Then temperatures are assumed that the

summer period is 40and winter period is -10. The

number of cycles is set 50 cycles, and after that the two

plane shear loading test was carried out for each

specimen.

Figure 2: Hot - cold temperatures repetition test

Figure 3 shows the two plane shear test specimen for

FRP model and V-plate (metal) model. V-plate model is

a test specimen for the comparison to FRP model. Table

1 shows the specimen list on the two plane shear test.

The quantities of specimens are 3 for each type ofspecimen.

Figure 3: Two plane shear test specimens

Table 1 Specimen list on the two plane shear test

TypeJoining

(Both sides)Wood Quantities

FRPFRP

(GUD12) Structural gluedlaminated wood

(JAS:E105-F300)

3

V-plateV-plate

(metal)3

On the other side, we carried out the exposure test by

natural environment on the outside of the laboratory.

Photo 1 shows the exposure test specimens. The two

plane shear loading tests were carried out to investigate

the initial performance, hot-cold repetition and exposuretest for 3 months. Photo 2 shows the equipment for two

plane shear loading test.

Photo 1: Exposure test specimens

Photo 2: Equipment for two plane shear loading test

Figure 4 shows results of the maximum load for two

plane shear loading test in each specimen. The graph

shows the average of maximum load for 3 specimens,white bar is the result for initial performance, gray bar is

hot-cold repetition (50 cycles) test, and black bar is

exposure test for 3 months. In this graph, the

performance for maximum load of FRP model is not so

protection film

reinforced fiber

Plastic

(Ultravioletrayed-hardening)

The sheet cross sectionUltravioletrayed-hardening

FRP

Setting time

for each step

1 1 minute

2 1 minute

3 90 minutes

4 1 minute

5 90 minutes

6 1 minute

Summer

Winter

300 200

105

150 150 100 100

Adhesion lengthFRP model

V-plate model



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Characteristic values Model A Model B

Yield rotation angle

y(rad)0.0266 0.0093

2/3Mmax

(kNm)57.4 58.4

Ultimate moment

Mu(kNm)78.5 82.4

Ultimate angle

u(rad)0.105 0.089

Stiffness

R(kNm/rad)1947 3779

Ductility factor

2.59 4.10

Structural characteristics factor

Ds0.489 0.373

Ultimate situation for Model A and B are shown inPhoto 4 - Photo 5. And, Photo 6 shows the detailed

destruction of the joint steel plate for Model A. Thefracture pattern was the steel plate edge rupture. Photo

7 shows the damage situation of the FRP (Model B). It

is shown that the FRP resists for the bending.

Photo 4: Ultimate situation for Model A

Photo 5: Ultimate situation for Model B

Photo 6: Destruction for Model A

Photo 7: The damage situation of the FRP (Model B)

5 CONCLUSIONSIn this study, the basic experimental tests which the

degradation accelerated test for temperature, outdoorweather tests were carried out to grasps durability

performance. Then, the verification experiment was

carried out for the joint element specimens of the large

section wood.

ACKNOWLEDGEMENTThis work was supported by JSPS KAKENHI 23686080.

REFERENCES[1] Julio F. Davalos, Youngchan Kim, Ever J. Barbero :

A layerwise beam element for analysis of frames

with laminated sections and flexible joints, Finite

Elements in Anslysis and Design 19, pp.181-194,1995

[2] Architectural Institute of Japan : Design Manual forEngineered Timber Joints. Maruzen, 2009.(In

Japanese)

[3] Architectural Institute of Japan : FundamentalTheory of Timber Engineering. Maruzen, 2009.(In

Japanese)


wcte12 - session 36 - connections 10.pdf

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