Trend of Steel Structure for Buildings in Japan · for Buildings in Japan Confidential 9th Feb ,...

1Copyright © 2015 JFE Steel Corporation. All Rights Reserved. Steel Research Laboratory

GEDIK & JFE Meeting and Joint Seminar in 2015

Trend of Steel StructureTrend of Steel Structure

for Buildings in Japanfor Buildings in Japan

Confidential

9th Feb , 2015

Takumi ISHII JFE-Steel Corporation


Trend of Steel Structure for Buildings Trend of Steel Structure for Buildings in Japanin Japan

1) Market trend of steel structure

2) Seismic design and requirements for steel products

3) Introduction of high performance steels


Buildings applied the advantages of steel Buildings applied the advantages of steel structuresstructures

Earthquake and Disaster-resistant Buildings

Rapid Construction

Stabilized Quality due to Industrial Production

・Attractive Design・Flexibility of Planning

Eco-friendly Materials

①①①①

②②②②

③③③③④④④④

⑤⑤⑤⑤


Buildings applied the advantages of steel Buildings applied the advantages of steel structuresstructures

Wide-span Building

High-rise Building

◆◆◆◆ Strength & DuctilityCompact cross-sectionReduction of column size

⇒ Spacious

◆◆◆◆ Rapid constructionQuick turnover

⇒ Economical

High-Rise or Wide-SpanBuildings in Japan

= Steel Structure


Market trend of steel structureMarket trend of steel structure


Domestic Demand for Steel Products Domestic Demand for Steel Products Destined for Construction in Japan Destined for Construction in Japan

Share of Steel Demand for ordinary steel products in 2012

Building construction

29.5%

Building construction

29.5%

Civil engineering

15.7%

Civil engineering

15.7%Shipbuilding

7.9%

Automobiles19.1%

Industrialmachinery

5.1%

Erectricalprocessing

4.2%

Others9.9%

Inport8.6%

Total：50million tons/year

Share of construction (civil engineering and building construction) in total domestic demand: 45.2%

Share of construction (civil engineering and building construction) in total domestic demand: 45.2%


Structural Types Adopted in Building Structural Types Adopted in Building ConstructionConstruction

Concrete-filled steel tube (CFT)

structure

Reinforced-concrete (RC) structure

Steel and reinforced-concrete

(SRC) structure

Steel (S) structure Wooden (W) structure


Floor Area of New ConstructionFloor Area of New Construction--Started Started Buildings by Structural Type in JapanBuildings by Structural Type in Japan

Other

Construction area（million m2） in 2012

55(41%)

46(34%)

30(22%)

2.8(2%)

Wooden

SRC

RC

Steel

CB

Steel StructureSteel Structure


Steel Products and Joining Technology for Steel Products and Joining Technology for Construction of SteelConstruction of Steel--frame Buildingsframe Buildings

� Wide-flange

� Square steel tube

� Plate

� Circular steel tube

� Welding

� High-strength bolt


Seismic design and requirements Seismic design and requirements for steel productsfor steel products


Seismic Design CodesSeismic Design Codes(Building Standard Law of Japan, revised and enforced in 1981)(Building Standard Law of Japan, revised and enforced in 1981)

• Primary design;Elastic design for Medium earthquakeDamage does not occur in the structure (deformation does not remain).

� Secondary design;Plastic design for Major earthquake Although damage occurs in the structure, collapse is prevented and human life is safely secured (deformation remains ).

Seismic intensity scale0 1 2 3 4 5– 5+ 6– 6+ 7

No damage Allowing damage but no collapse

Fears of collapse

Steel structures are suitable for seismic design because of their excellent ductile behavior during earthquake.

Steel structures are suitable for seismic design because of their excellent ductile behavior during earthquake.

(JAPAN)

MKS Seismic intensity

I II III IV V VI VII VIII IX X XI XII


Revised seismic design method in JapanRevised seismic design method in Japan

Seismic design of two stages(Revised seismic design method)

①Surface maximum acceleration 80-100 gal

：Elastic design

No damage to the building (Deformation does not remain)⇒ Primary design

② Surface maximum acceleration 300-400 gal

：Plastic design

a damage to the building, prevents collapse (Deformation remain in the building after the earthquake)

⇒ Secondary design


Seismic Design of SteelSeismic Design of Steel--frame Buildingframe Building

・Framing is retained in elastic range

during small and medium

earthquakes (no damage)

・During great earthquake, damage

(plasticization) is allowed only for

framing, but building collapse is

prevented, and human lives are

protected.

Great quake level

Medium quake level

Deformation

Seismic ForceGreat quake level

Large strength is necessary for holding elastic response

Deformation

Force


Structure characteristic coefficientStructure characteristic coefficient

Q δ

Q

δ

Q

δ

1.0

Ds

Ds=0.5

Ds=0.25

Q

δ

Q

δ

Elastic response structure（Elastic system）

Structure with toughness（Elasto-plastic system）

Same seismic performance

Energy is equal

Ds=2μμμμ-1

1

μ

μμ

Ds : depend on ductility Ds : depend on ductility of structure & membersof structure & members(0.25(0.25～～0.5)0.5)


Material Properties of Steel ProductMaterial Properties of Steel Product

Stress-Strain Relation of Steel Product

Plastic range

Upper yield point

Lower yield point

Stress

Tensile strength

Fracture

StrainPermanent elongation

Elastic range

■ Important in design: Yield point

(not Tensile strength)

■ Yield ratio=Yield point/Tensile strength (A/B)

A

B


Mechanical Properties of Steel for Seismic Mechanical Properties of Steel for Seismic PerformancePerformance

◇Upper limit of the yield ratio(Low yield ratio)

⇒realize the excellent deformation performance of the steel member

◇Upper limit of the yield point(Reduction of deviation)

⇒realize the deformation performance of the building as designed

A B68

72

76

80

84

88

Yil

ed

Ra

tio

(%)

High Yield ratio

Steel

Low Yield ratio

400

300

350

250

200

YX

Yie

ld P

oin

t(N

/m

m2)

F

Steel

deviation

Upper limit of the yield ratio

Upper limit of the yield point

Lower limit


Effect of Yield Ratio on Seismic ResistanceEffect of Yield Ratio on Seismic ResistanceS

tre

ss

Strain

ⒶⒶⒶⒶHigh yield ratio

ⒷⒷⒷⒷLow yield ratio＜＜＜＜Framing using steel product ⒶⒶⒶⒶ＞＞＞＞

＜＜＜＜Framing using steel product ⒷⒷⒷⒷ＞＞＞＞

Seismic force

Seismic force

Small deformation capacity∥∥∥∥

Less seismic energy absorption

Large deformation capacity∥∥∥∥

Increased seismic energy absorption

When yield ratio is low, plastic

range becomes wide, and

plastic deformation capacity

becomes high.

＜＜＜＜ Steel product ＞＞＞＞

Plasticizing section


Moment distribution of the steel frame in Moment distribution of the steel frame in earthquakeearthquake

TS

High YR

DeformationS

eis

mic

Fo

rce

＜Absorption energy of steel frame＞

L

Tensile force generated in the lower flange

SeismicForce

LLow YR

YP AYP B

By using the steel with low yield ratio, it is

possible to realize the building that has large

amount of plastic deformation capacity.


Effect of Yield Point Deviation on Seismic Effect of Yield Point Deviation on Seismic ResistanceResistance

Pattern B

Pattern C

Collapse type assumed in design:

Pattern A

●Plasticizing section

Pattern A

Pattern C

Pattern BSeismic

force

Deformation0

When

deviation of

yield point is

large:


Fracture at beam end

Fracture at beam end

Column

Flange of H-beam

Earthquake Damages of Steel StructuresEarthquake Damages of Steel Structures

Steel toughness ＆＆＆＆Weldability


Requirements for Steel Products for Building Requirements for Steel Products for Building StructuresStructures

1.Securement of plastic deformation capacity

Specification of upper limit for yield point and yield ratio

2. Securement of weldability

Specification of upper limit for Ceq, Pcm

3. Securement of through thickness-direction properties

Prescription of lower limit for thickness-direction reduction

of area

4. Securement of nominal cross-section dimension

Stricter allowable difference of minus-side thickness

5. Selection of optimum grade taking into account the

application section (Grades A, B and C)


SN490SN490 -- Specification Specification --

Design

-ation

Thick

-ness

mm

Specified Properties

Strength・・・・ToughnessWeld-

ability

ΔΔΔΔYP,

ΔΔΔΔTS,

YR80%

Charpy

Impact

Test

through thickness-direction

property

Ultra-Sonic

Test

（（（（plates））））

Ceq

（（（（P,S etc.））））

S355J0

TS470

YP345 MPa

16 ≦≦≦≦t

≦≦≦≦ 250－－－－ ●●●● －－－－－－－－ ●●●●(CEV)

SN490

TS490

YP325 MPa

16 ≦≦≦≦t

≦≦≦≦ 100●●●● ●●●● ●●●● ●●●● ●●●●

Rolled Steel for Buidling Structure（（（（JIS G 3136））））

YR(Yield Ratio )=YS(Yield Strength) ／／／／TS(Tensile Strength)ｘｘｘｘ100％％％％

Applicable to elasto-plasitc design (Grade50)

ENEuropeanStandards

JISJapaneseIndustrialStandard


LineLine--up of SN Productsup of SN Products

WideWide--flange, flange,

plate, etc.plate, etc.

Circular tubeCircular tube Square tubeSquare tube

JIS G3101 JIS G3106 JIS G3444 JIS G3466

SS400SS490

SM400A､B､CSM490A､B､C

STK400STK490

STKR400STKR490

JISJIS G3136G3136 JIS G3475JIS G3475

Approved product by Ministry of Land, Infrastructure, Transport and Tourism

SN400ASN400A､､BB､､CC

SN490BSN490B､､CCSTKN400WSTKN400W､､BB

STKN490BSTKN490BBCR295BCR295

BCP235BCP235､､325325

Genera

l st

ruct

ure

sB

uil

din

g

str

uctu

re


Introduction of high performance steelsIntroduction of high performance steels


High Yield Strength SteelHigh Yield Strength Steel

0

200

400

600

800

1000

1200

YPYP

YP

TS

TS

TSMPa

SN490(Grade 50)

SA440(Grade 65)

H-SA700(Grade 100)

Ductility, Weldability,through thickness-direction

Property

New High-Strength

Yield point325 MPa

325440

700

490590

780


SA440SA440 -- Application example Application example --

Tubular Column

Diameter : 2,000mm, t=75mm

Roppongi Hills (238.1m, 54 story, 2003)


TOKYO SKY TREETOKYO SKY TREE®®

NEW No.1 TOWERfor ground-wave digital televisionbroadcasting

634ｍｍｍｍ

333ｍｍｍｍ321ｍｍｍｍ

TOUR EIFFEL TOKYO TOWER TSTCompletion 1889 1958 2011

Steel about 7,300ton about 3,600ｔ about 40,000ton

Joint Rivet 2.5million Rivet 1.2million Welding ,Bolts


High strength steel used in TSTHigh strength steel used in TST

JFE 500N/mm2

High strengthsteel tubes(φφφφ2300x100））））support TST

JFE 630N/mm2

High strengthsteel tubes(φφφφ1200x60)support GainTower of TST

We suppliedhigh strengthsteel pipeof 8,300tons


The largest sections

(at the foot of the Tower)

Diameter: 2,300mm , t=100mm

HighHigh--strength Pipes for Tokyo Sky Treestrength Pipes for Tokyo Sky Tree

(634m, 2011)


Damage of steel structure by fireDamage of steel structure by fire

Full scale fire experiment by Institute of British Architects

Emerged flamefrom window

Buckling of beam end

Crack of floor slab


Basic view for ensuring fire resistanceBasic view for ensuring fire resistance

Preventing temperature increaseby fireproof coating

Rock-wool

Spraying of Rock-wool


Fire Resistant Steel (FR)Fire Resistant Steel (FR)

Temperature（℃）

Str

ength

N/m

m2

The yield point : at 600ﾟC > 2/3 × at room-temp.GuaranteeGuarantee


FR Steel FR Steel -- Application example Application example --

Covered withfireproof coating

FR steel without fireproof coating


BuiltBuilt--up Column up Column welded by high heatwelded by high heat--input welding methodinput welding method

Submerged arc weldingSubmerged arc weldingHeat input 20～60 kJ/mm

Corner weldCorner weld

Diaphragm plate weldDiaphragm plate weld

ElectroElectro--slag weldingslag weldingHeat input

50～100 kJ/mm


BuiltBuilt--up Column up Column welded by large heatwelded by large heat--input welding methodinput welding method

Weld MetalWeld Metal HAZ HAZ

Base MetalBase Metal

ConventionalConventional EWELEWEL

Microstructures

“JFE EWEL” Technology for Excellent Quality in HAZ of High Heat Input Welded Joints

0

50

100

150

200

250

FLHAZ

ConventionalConventionalEWELEWEL

Charpy absorbed energies ofSAW welded joints

Ab

sorb

ed e

ner

gy(

J)


View of damage control designView of damage control design

Preventing destruction Preventing damage

Earthquake

Energy absorption by using

damage of frame (Plasticity hinge)

Energy absorption

by using damper

Hysteresis damper

Conventional structure Plasticity hinge Structure with hysteresis damper


Shear Link type Wall panel type Stud type Brace type

1000

800

600

400

200

1000

800

600

400

200

1000

800

600

400

200

1000

800

600

400

200

Types of damperTypes of damper

Ultra mild steel is mainly used

780N steel for building

Strain(%)

Stress(N/mm2)


Usage example:Usage example:Brace typeBrace type

The Shizuoka Prefecture Government East Office


Seismic Retrofit by Using CHS BracingsSeismic Retrofit by Using CHS Bracings

by using CHS Bracings

Advantages;

- short construction period

- wider view

- slender and beautiful

Reinforcing on the outer surface of a building


Seismic Retrofit by Using CHS BracingsSeismic Retrofit by Using CHS Bracings

School Building in Korea RC Building in Japan


TeTeşşşşşşşşekkekküürr ederimederim

energy dissipative brace

FKUDA DENSHI ARENA

42

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