No. 58 December 2019

STEEL CONSTRUCTIONTODAY & TOMORROW

http://www.jisf.or.jp/en/activity/sctt/index.html

Feature Article

Recycling and Lifecycle
Assessment of Steel Products
1 Initiatives to Treat Environmental Issues and Mitigate
Global Warming by the Japanese Steel Industry

5 Standardization of LCI Calculation

Methodology for Steel Products and
Its Development in Japan

9 Recycling and the Future of
Steel Materials

13 Green Steel Seminar Held
14 Introduction of ISO 20915 at the Plenary Session of
SEAISI Annual Conference

Serial Article: Latest Design of Steel Buildings in Japan (4)GINZA KABUKIZA
15 GINZA KABUKIZA: Buildinga High-rise Office Toweron an Open Space ofTraditional Kabukiza
Theatre Using a
Mid-storey Mega Truss

Published Jointly by

The Japan Iron and Steel Federation
Japanese Society of Steel Construction

Feature Article: Recycling and Lifecycle Assessment of Steel Products (1)Initiatives to Treat Environmental
Issues and Mitigate Global Warmingby the Japanese Steel Industry

by Hidekazu Matsubara
Secretary, Committee on Environment-friendly Steel for Construction
The Japan Iron and Steel Federation
Amid growing concerns about global environmental issues, the Japanese government established the Council of Ministers
for Global Environment Conservation in
1989. With this establishment, diverse efforts that aim at mitigating global warming have been promoted nationwide. In
recent years, in order to work out andpropose the “Long-term Low Greenhouse Gas Emission Development Strategies (Long-term Strategies),” which has
been required to submit by 2020 in the
Paris Agreement of COP21, the “Conference on Japan’s Long-term Strategy
under the Paris Agreement” was established, which has started examinations
involved in the Long-term Strategy.
In light of such movements in Japanand abroad, the Japanese steel industry
is promoting various measures that aim
at mitigating global warming. One of
specific measures being promoted is the“Implementation Plan to Achieve a Low
Carbon Society.” In addition, staring
fixedly at ongoing global warming issues
after 2030, the steel industry has worked
out the “Vision for Long-term Measures
to Treat Global Warming Issues” thataims at realizing its final goal, the production of “steel with no CO2 emissions
in its production process.”
The following article introduces theJapanese steel industry’s initiatives totreat environmental issues and mitigate
global warming that have been promoted so far, and future plans to further mitigate global warming.
Measures to Treat Environmental
Issues in Iron and Steel Production
Triggered by the oil crisis that occurredin the 1970s, the Japanese steel industry
has promoted various efforts to treat environmental issues involved in iron andsteel production, among which are:
• Process improvement measures mainly
for the continuation of production processes, such as the introduction of continuous steel casting equipment
1 Steel Construction Today & Tomorrow December 2019

• Effective utilization of byproduct gas

where byproduct gas generated in ironand steelmaking processes is recovered
and used as energy to operate iron- andsteelmaking equipment
Recoveryof waste energy and its effective•
utilization as a source for power generation• Introduction of energy-saving technologies
developed by capitalizing on the effective
utilization of waste materials as resources(Refer to Fig. 1)
The Japanese steel industry has successively introduced these high energy-efficient processes into iron and steel production, thereby attaining a reduction of about
30% of unit energy consumption per tonof steel produced compared to the levelin the 1970s. As a result, the industry hasrealized iron- and steelmaking processes
that demonstrate the highest energy-efficiency in the world. (Refer to Fig. 2)
In addition to the efficient energy use
mentioned above, the Japanese steel industry has put into effect various kindsof other environmental measures, one ofwhich is the effective use of slag generated in iron- and steelmaking processes.
For example, because blast furnace cement produced employing blast furnace
slag can be produced without the use of
crushing and sintering processes that areused in the production of regular cement,
blast furnace cement has a great impact
on environmental protection or the reduc-Fig. 1 Development of Eco-processes in the Japanese Steel Industry

’70s

’80s

First oil crisis’90s● Innovation and improved

’00s

’10s

Kyoto Protocol

Artificial intelligence, improved
logistics efficiency

efficiency of process

Continuous casting, continuous Pulverized coke injection, Next-generationcoal moisture control
coke-oven technology
annealing and processing line
● Effective utilization ofGas holder, gas turbine
compound power generation

byproduct gas● Recovery of

Blast furnace top-pressure recovery
waste energy turbine, coke dry quenching

Regeneration
burner● Recycling use ofwaste material

Waste plastics, used
tire, dust, sludge

Fig. 2 International Comparison of Unit Energy Consumption
in the Steel Industry
Index set Japan as 100 (unit consumption per ton of steel produced)
140
130

116

117

Korea Germany China

UK

120
110
100

100

103

109

122

123

France Brazil

India

119

128

130

Russia

USA

90
80
70

Japan

Source: RITE-Estimate of Unit Energy Consumption for 2015; Conversion to indices by
the Japan Iron and Steel Federation

tion of CO2 emissions during production.
Further, the industry also contributes
towards the preservation of not only air
but also water quality. Emissions of SOx
and NOx at steelworks are considerably
reduced by the adoption of desulfurization and denitrification equipment. In
terms of the vast amount of water usedat steelworks, more than 90% of all water use is put back into circulation withthe adoption of water quality purificationequipment. Capitalizing on these environmental measures, the steel industry
contributes toward the improvement of
the environment.
Measures to Mitigate Global
Warming by the Japanese Steel
Industry
Making the most of these world’s highest
energy-efficient processes, the Japanese
steel industry has planned and put into
practical use measures to mitigate global warming. Specifically, these measures
are promoted based on the “Implementation Plan to Achieve a Low Carbon Society: Phase I (~2020)” that is supported
by four core activities: the effective useof three eco-approaches-eco-processes, eco-solutions and eco-products-andthe development of the innovative process COURSE50 (CO2 Ultimate Reduction System for Cool Earth 50). (Refer
to Fig. 3)

Fig. 3 Basic Concept for Long-term Measure to Mitigate Global Warming in the Japan
Iron and Steel Federation (Three ecos+Innovative technology development)
Eco-process

Further improvement of world-classenergy use efficiency in iron- andsteelmaking processes

Eco-productContribution towards CO2 emissions
reduction at the stage of steel application as theend product through supply of high-performancesteel products-eco-products are indispensable
in structuring low-carbon society

Eco-solution

Contribution towards CO2 emissions reduction
on a global scale through transfer of Japanese
steel industry’s world-class energy-saving
technologies mainly to developing nations
and their diffusion in those nations

Innovative technology: COURSE50, ferro coke
Extremely-innovative technology: hydrogen-applied reduction process, CCS, CCU• Eco-processes
Eco-processes lay out the world’s highest energy-efficient processes mentioned
above, for which the further improvement of energy efficiency is being promoted. Recently, R&D efforts are being directed towards the introduction of
next-generation coke ovens and the enhancement of the operational efficiencyof power generation equipment.
• Eco-solutions
Eco-solutions aim at the promotion ofenergy savings by means of two major approaches: the transfer of energysaving technologies (BAT: best available technology) developed and put
into practical use in the Japanese steel
industry to China, India, ASEAN andother nations where the steel industry

is achieving remarkable developments;
and the effective use of the frameworkof multinational cooperation programs
such as the Global Superior Energy Performance Partnership (GSEP). The Japanese steel industry has contributed towards reducing CO2 emissions throughthese approaches on a global scale. (Refer to Fig. 4)
A study made by the International Energy Agency shows that in overseas steel
industries there is great potential for energy savings (Fig. 5) that can be achievedby the introduction of advanced energysaving technologies (most of these technologies developed in Japan). The Japanese steel industry will continue to tackle
the development and supply of eco-solutions in the future.

Fig. 4 Transition in International Cooperation Programs to Support Eco-solutions
2003

2004

2005

2006

2007

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

Japan-China Steel Industry Environmental Protection and Energy Conservation Technology Conference (2005~)
The Public and Private Collaborative Meeting between
Indian and Japanese Iron and Steel Industry (2011~)

Bilateral and regional
cooperation programs

Multilateral
cooperation
programs

ASEAN-Japan Steel
Initiative (2014~)

APP (Asia Pacific Partnership)
Steel TF (2006~2010)

ENCO (Environment Committee) (~2009)

GSEP (Global Superior Energy Performance
Partnership) Steel WG (2010~2015)

EPCO (Environmental Policy
Committee) (2010~2013)

ECO (Environment Committee)(2014~)“CO2 Breakthrough Program”: Participating with COURSE50 (2003~)
CO2 Data Collection (2007~)

International Cooperation
Programs (World Steel
Association and others)

Development of ISO 14404 (2009~)• ISO 14404-”International standard for the calculation of CO emission from steel plants”• Issue of the standard for steel plant with blast furnace and electric arc furnace in22013 and steel plant with electric arc furnace and DRI facility in 2017

December 2019 Steel Construction Today & Tomorrow 2

Fig. 5 International Comparison of Energy Saving Potentials in the Steel Industry (2011)
7

0.45

9

6

3

3

2

0.30

6

0.25
0.20

3

0.15

GJ/t steel

4

EJ

EJ

6

GJ/t steel

0.35

5

0.10

1
0

9

0.40

0.05
0

World China

0OECD Russia Ukraine United Brazil
Korea Japan Canada South
Other
EuropeStatesAfricaCOG recovery
Blast furnace improvement
Improved BOF gas recovery
Switch from OHF to BOF

0.00

India

CDQ (or advanced wet quenching)

Efficiency power generation from BF gas

Reduced electricity use from continuous casting

Savings potential (GJ/t steel)Source: Energy Technology Perspective 2014 of IEA• Eco-products
Eco-products mean those steel productsthat allow CO2 emissions reductions, lessenvironmental burdens, improved fuel efficiency and other approaches in the stageof end products manufactured by the optimum use of the specific performances offered by eco-products. For example, end
products manufactured using high-performance steel products contribute toward
reducing CO2 emissions, or eco-products demonstrate eco-friendliness in theapplication stage. A typical eco-productis high-strength automotive steel sheets.
From the 1970s to the present, higher tensile strength has been demanded for automobile steel sheets to meet diverse social
backgrounds and needs, or to meet theneed for lighter-weight automobiles thatallow for improved fuel efficiency. Higher-strength automobile steel sheets developed by the Japanese steelmakers havecontributed toward the reduction of CO2
emissions by lightweight automobiles on
a global scale. (Refer to Photo 1)
However, the level of characteristic values achieved in terms of tensile
strength or put into practical use by Japanese steelmakers is only 1/2 or 1/3 that of
the theoretical value (refer to Fig. 6). Given this, the Japanese steel industry is striving not only to develop higher-strength

steel products but also to support futuresocial infrastructure through the development of next-generation steel products to
prepare for the arrival of a hydrogen infrastructure. At the same time, the industry is
pushing forward with the task of contributing to reduced CO2 emissions over theentire life cycle of steel products.
In the development of innovativeironmaking processes, R&D efforts arebeing directed towards two targets: theutilization of hydrogen-reduction of ironore in the blast furnace process where
CO2 emissions are highest among theiron- and steelmaking processes; andthe COURSE50 project in which tech-

nological developments are being madewith the aim of reducing CO2 emissions
by 30% in iron and steel production bymeans of the separation and recovery ofCO2. The wider diffusion of COURSE50
put into practical application by 2030 istargeted to be completed by around 2050.
As a means to reduce CO2 emissions iniron- and steelmaking processes, the Japanese steel industry has worked out the“Implementation Plan to Achieve a Low
Carbon Society: Phase II” for 2030. In
terms of total CO2 emissions in the steel
industry, Phase II targets higher-level reductions by adding specific reduction targets to be achieved by eco-products, eco-

Photo 1 Steel products conducive to reducing CO2 emissions
Motors for hybrid and electric vehicles:
Improved fuel efficiency, higher output
and downsizing of motors attained by
the use of high-efficient, non-oriented
electrical steel sheet

Automobile and industrial machinery parts:
Multi-stepping, downsizing and lighter weight oftransmission gears attained by the use of high-strength
gear steel→Improved fuel efficiency

Fig. 6 Development of High-strength Steel Products and Future Development Potential
1960s

1970s

High economic
growthFuel efficiency
improvement

Automotive steel sheet

0

1

3

1990s

2000s

2010s

Kyoto Protocol

Paris Agreement

Change in social background and need
Collision safety
High-strength steel~440 MPa
grade

Mild steel(ease of processing)

Bridge cable
2

1980s

Steel cord
4

3 Steel Construction Today & Tomorrow December 2019

Global warming~580 MPa
grade

Extrahigh-strength steel
780~980 MPa
1,180 MPa
grade
grade~

Potential for higher tensile strength
Piano wire
Theoretical tensile strength: 10.4 GPa
5
6
7
8
9
10
11
Tensile strength (GPa)processes and eco-solutions over those of
Phase I (Table 1). In the field of innovative process development, the steel industry has a plan to promote the developmentof ferro coke, an innovative ironmaking
raw material, in addition to COURSE50.
Future Measures to Mitigate Global Warming in the Japanese Steel
Industry
The Paris Agreement targets “holding
the increase in the global average temperature to well below 2°C above pre-industrial levels.” Keeping this statement in
mind, it will absolutely be necessary to develop extremely-innovative ironmaking
technology beyond technologies currently
in use as well as innovative technologies
which are under development. Given sucha situation, the Japanese steel industry is
directing its full efforts to the developmentof COURSE50, ferro coke and other innovative ironmaking technologies towards
their practical application by 2030. Whenthese technologies are put into practicaluse, CO2 emissions from the use of natural resources are expected to be reducedby 10% from current emissions levels (excluding reductions due to the effect of carbon dioxide capture and storage).
For the moment, the blast furnace method is considered the mainstream method in ironmaking from both an economic and technical perspective, and therefore
it will be necessary to promote the establishment of low carbon emissions-typeironmaking technology on the assumption that blast furnaces will continue to be
applied in the future. However, it will be
impossible to achieve the long-range level of global average temperatures set out
in the Paris Agreement with only the useof such measures, which will thus require
the development of extremely-innovativetechnologies beyond those currently in development. (Refer to the scenario for the
maximum introduction of extremely-innovative technologies shown in Fig. 7)
To these ends, capitalizing on knowledge to be obtained in the development of
COURSE50 and ferro coke as the foothold, the Japanese steel industry is promoting three major development challenges: hydrogen-applied reduction
process technology that finally allows forzero-emissions from the ironmaking process; CCS (carbon capture and sequestration) in which CO2 emitted from theironmaking process is separated, recovered and stored; and CCU (carbon capture
and utilization) in which the valuables areformed using CO2 as the raw material.
Because the hydrogen to be used in
the hydrogen-applied reduction process
is used not only as a raw material for
ironmaking but also as the fuel source
for automobiles and other extensive civil
sectors, the major precondition is the development and improvement of the technology and equipment to produce hydrogen as a common energy carrier forindustrial and social infrastructure. Particularly, the important requisite for thehydrogen used for the production ofsteel, the basic industrial material, is carbon freeness and the further availabilityof a low-cost, stable supply. Further, inthe practical use of CCS, it will be necessary to solve various tasks beyond technological tasks, such as securement of
CO2 storage sites, social receptiveness,
project implementation organizations
and the treatment of economic burdens
in addition to the development of technology to allow the low-cost transportand storage of large quantities of CO2.
Fig. 7 shows the roadmap towards (scenario for) the development of extremelyinnovative technologies.
Initiatives towards Sustained
Mitigation of Global Warming
The Japanese steel industry has thus far
tackled environmental issues capitalizingon the advanced technologies introduced
above. In the future, in order for Japan
to attain the medium-range target (2030)
stated in the Paris Agreement, the industry will steadily promote the “Implementation Plan to Achieve a Low Carbon Society.” At the same time, regarding thelong-range target (after 2030) that aims
at produce “steel with no CO2 emissions
in its production process,” it will sustain its initiatives for long-range global
warming mitigation measures that will
be obtained through the promotion of
eco-products, eco-processes and eco-solutions and the development of innovative technologies. ￭Table 1 Targets for CO2 Emissions Reduction by the Use of Three Ecosin the Japanese Steel Industry
Phase II
Phase I(~2030)(~2020)9,000,000 tons-CO2
5,000,000 tons-CO2*
Eco-process(reduction from BAU)
(reduction from BAU)
Eco-solution
80,000,000 tons-CO2
70,000,000 tons-CO2
Eco-product34,000,000 tons-CO2
42,000,000 tons-CO2*Of the emissions reduction target of 5,000,000 tons-CO2, while concentrating on the reductionof 3,000,000 tons-CO2 by means of energy savings and other self-efforts, the emissions
reduction attained by the increased collection of plastic wastes and other waste materials
compared to the FY2005 collection return is to be counted as the emissions reduction return.
Implementation of Plan toAchieve Low Carbon Society

Fig. 7 Roadmap towards (Scenario for) Development of Extremely-Innovative Technologies
Technological development peculiar to the steel industry
Hydrogen-applied reduction method in blast
COURSE50
furnace process (hydrogen inside steelworks)
Hydrogen-applied reduction method in blast
Super COURSE50
furnace process (hydrogen outside steelworks)
Hydrogen-applied
Hydrogen-applied reduction process
reduction process
without use of blast furnace
CCS

Recovery of CO2 from blast furnace gas

2010

Stepping-up

2030
Development

Stepping-up
Development

Conversion of CO2 arising at steelworks
to valuables
CCS: Carbon capture and sequestration CCU: Carbon capture and utilization
Technological development for socially common infrastructure
Zero emissions in system power supply by use of
Zero emissions at
nuclear power and renewable energy
power source
Low-cost mass production technology by use of nuclear
Carbon-free
power and renewable energyhydrogen
CCU

CCS/CCU

2020

Development

Development of low-cost storage technology, selectionof burying site, conversion to valuables

Development

2040

2050

2100

Practical
operation

Development

Practical
operation
Practical
operation
Practical
operation

Development

Practical
operation

Development

Practical
operation

Development

Practical
operation
December 2019 Steel Construction Today & Tomorrow 4

Feature Article: Recycling and Lifecycle Assessment of Steel Products (2)Standardization of LCI Calculation
Methodology for Steel Products and
Its Development in Japanby Tomohisa Hirakawa
Vice Chairman, Committee on Environment-friendly Steel for Construction
The Japan Iron and Steel Federation
Standardization of LCI Calculation
Methods with Consideration of
Recycling Effect
In assessing the effect on the environment of many products used in our daily life, while attention is liable to be focused on the stage of production andapplication of these products, it is notalways correct to judge environmental
performance only in the stages of production and application. Rather, it is important to assess the effect of products on
the environment over the entire lifecycleof products that covers processes fromthe mining of raw materials to the manufacture and application of products andfurther to recycling after the disposal of
used products. That is, lifecycle assessment is important in assessing the environmental performance of products.
Nearly all steel products are recovered as steel scrap after automobiles andother products employing steel products
reach the end of their service life. Recovered steel scrap is then reborn as renewed
steel products, which are then applied to
new end products. This process is repeated for many types of end products many times.
So far, standards have not yet been established to assess environmental burdens over the entire lifecycle, covering
even recycling as scrap after the disposalof end products. To cope with such a situation, ISO 20915 “Life cycle inventory
calculation methodology for steel products” and JIS Q 20915 “Life cycle inventory calculation methodology for steel
products” (hereinafter referred to as the“Standards”) have been put into effect,
which allow inventory calculations used
for assessing the environmental burdens
on the entire lifecycle of steel products.
The Standards originate from the LCI
calculation methodology prepared by
the International Iron and Steel Institute (currently World Steel Association:worldsteel) through organizing the calculation method for the life cycle inventory
5 Steel Construction Today & Tomorrow December 2019

(hereinafter referred to as the “LCI”) in
1997, which takes into account the scrap
recycling of iron and steel products, using the Methodology Report publishedby the Institute. In 2015, the Japan Iron
and Steel Federation (JISF) proposed theTechnical Committee ISO/TC 17 for the
standardization of the LCI calculation
methodology, which led to the establishment of ISO 20915 “Life cycle inventory calculation methodology for steel
products” in November 2018 and JIS Q
20915 having nearly identical content inJune 2019.
While the conventional systemboundary (range applied for LCI calculation) used for the LCI calculation methodology generally covers the processes from the mining of raw materials to
product shipment, the system boundary
in the newly-established Standards cov-

ers the processes from the mining of raw
materials to product shipment taking into account the recycling effect obtainedby scrap recovery and application (Fig.
1). In the case of LCI calculation using
the Standards, LCI is obtained by adding
LCI (B1) occurring due to scrap input
and LCI (B2, minus value) occurring due
to scrap recovery to LCI (A) occurring in
the processes from the mining of raw materials to product shipment (Fig. 2)
JISF and worldsteel periodically collect from domestic and global steel industries the information on operating results data of their member companies
to calculate and make public the average values for global warming potential(GWP) pertaining to major steel products. The GWP data is available at thewebsites of these two organizations.
In the following three chapters, theFig. 1 System Boundaries Used in LCI Calculation Methodology
Conventional system boundary
From raw material mining to product shipment
Mining of raw
materials

Production ofiron and steel
products

Application ofsteel products

Service life ofsteel products

System boundary in ISO 20915 and JIS Q 20915
From raw material mining to product shipment in which the recycling effect is taken into accountMining of raw
materials

Production ofiron and steel
products
Use ofsteel scrap

Application ofsteel products

Service life ofsteel products

Taking into account the recycling effect

Recovery ofsteel scrap

Fig. 2 LCI Calculation Methodology Adopted in JIS Q 20915
Environmental effect (index)
2.0
1.5
1.0

Scrap recycling effect

0.5
0.0
-0.5
-1.0
-1.5

A : LCI covering the process B1 : LCI occurring
B2 : LCI occurring
due to scrap input
from mining of naturaldue to scrap
resources to shipment ofrecoveryiron and steel products(Scrap recycling effect is nottaken into account)

A+B1+B2 :LCI that reflects scrap
recycling effectSource: “Fig. 3 Concept of LCI Calculation for Steel Products” in JIS Q 20915

Fig. 3 Scrap Recycling under Market Economy (2017)
921
(USA)

38,20039,465EU15
29,093

10,403

4,119
(USA)

1,382

CanadaCIS

1,489

1,058 2,458
3,364

8,208

8,143

232

147

1,094

451

Africa
2,477

100
(USA)
494

USA

384
482

206

2,615
Oceania

Transaction volume
Export amount
Area

108

425
(Africa)
2,292

2,575

664

1,986

(European nations)
4,119

4,636

6,766

4,960 31,349

15,016

919

Japan

Asia

Middle East

(European nations)
921
3,173

2,115

6,792

1,954
1,891

425
(USA)

3,135

4,409

595

5,787

Other
Europeannations
24,875(unit: 1,000 tons)(Middle East)
494

Import amount

Central andSouth America
2,644(Transaction volume
less than 1,000 tons:
Eliminated)

Source: International Steel Statistics Bureau, World Steel Association, the Japan Ferrous Raw Material Association

Fig. 4 Environmental Burdens Occurring during Regeneration of Steel Products
Iron ore

Naturalresource

Iron

Iron- andsteelmaking
process

Steelproduct

Photo 1 Magnetic separation of used steel
products from waste materials

Photo: The Japan Iron and Steel Federation

background for and concept of the Standards are introduced.
Overwhelming Predominance inTerms of Recyclability
The most noteworthy feature of the Standards lies in the full consideration paid
to the recycling effect peculiar to steel
products. When citing steel’s advantages
in terms of recycling, the following fiveadvantages can clearly be seen, which al-

Even after the “end products” reach an end of their service life,the “material” used for producing the end product is regenerated
while maintaining the characteristic properties peculiar to iron.

Fabricated(end)product

End of service
life of fabricatedproduct

Steel
scrap

low closed-loop recycling (any end product and many times) of steel products.
• Ease of Separation
As is well known, a magnet attracts steel.
Even if steel products are disposed together with other waste, steel is easily
separated from disposed waste with theuse of a magnet (Photo 1).
• Establishment of Recycling
under Market Economies
Steel scrap is not the waste material but“the valuable,” and thus steel scrap has
already been transacted worldwide basedon market principles (Fig. 3).
• Less Environmental Burdens
during Regeneration
Once iron ore is reduced to iron
(Fe2O3→Fe), the generation of environmental burdens occurring in the subsequent stage of regeneration from scrap
to steel can be suppressed to a minimum
level (Fe→Fe), and further it is possible
to repeat the environmental burden-free
operation in every regeneration processthat follows (Fig. 4).

Iron- andsteelmaking
process

Iron

Steel
product• Less Quality Deterioration

during Regeneration
At the stage of regeneration from steel
scrap to steel, most of the impurities contained in steel scrap can be removed asslag and gas (Fig. 5).
• Possibility of Regeneration toDiverse Types of Steel Products
The metallic structure of steel regenerated from scrap is reset at the stage ofre-melting the scrap, and steel thus obtained can be processed to various kinds
and types of steel products by means of
microstructure control employing performance build-in technology (Fig. 6).
Compatible Use of Blast Furnaces
and Electric Arc Furnaces
The iron and steel production method
can roughly be classified into the blast
furnace (BF) method and the electric arc
furnace (EAF) method. In the BF method, pig iron is produced mainly from ironore, and the carbon contained in pig iron(molten iron) is removed using a basic
December 2019 Steel Construction Today & Tomorrow 6

oxygen furnace to produce steel. Meanwhile, in the EAF method, steel scrap is
re-melted using arc heat, during which
the chemical composition is adjusted
to produce steel. Even in the BF method, there are cases in which steel scrap
is used from an economical viewpoint,
and further in the EAF method, there arecases in which pig iron is used to maintain the quality level of the steel. (Refer
to Fig. 9)
Fig. 7 shows the production of steel
products around the world since 2000
using the BF and EAF methods. Production employing the BF method is far
more than that employing the EAF method, and the BF method surely meets thegrowing demand for steel products. The
reason for this is that, while iron ore canbe mined according to the level of demand, the available amount of steel scrap
is limited because scrap, so to speak, exudes from the society.
In this way, steel scrap is effectively reused in both the BF and EAF methods while at the same time steadily increasing the steel stock in society by theuse of steel products produced from blast
furnace-basic oxygen furnace steel. The
per-capita steel stock in matured societies in Japan, US and Europe amounts toabout 10 tons, but the average per-capita steel stock in the world amounts toonly about 4 tons (Fig. 8). For the moment, the age of compatible use of the
BF and EAF methods will continue, under which the BF method is expected toplay a pulling role towards the growth ofsocial steel stock.
Concept of LCI Calculation of
Steel Products
The LCI calculation of steel products is
explained by setting the iron ore-derived
LCI as Xpr, steel scrap-derived LCI as
Xre, scrap recovery rate (recycling rate)as RR and the molten steel yield during regeneration of steel scrap as Y, andfurther, in order to promote understanding of the concept of LCI, by giving theassumed values prepared by simulating the actual returns in four respective
items shown above-Xpr=2.0 (t-CO2),
Xre=0.5 (t-CO2), RR=0.9 and Y=0.9(Fig. 9).
In the situation where both the BF
and EAF methods are used in iron andsteel production, how should the LCIof steel products be calculated? Should
the LCI be calculated for the steel products separately via the BF method or via
the EAF method, or via a single linked
7 Steel Construction Today & Tomorrow December 2019

process covering both methods? Because steel scrap used in the EAF method comes certainly via the BF method inwhich iron ore is reduced to iron, there isa causal relationship between these two
methods, and thus it is impossible to di-vide the two methods for the LCI calculation. Therefore, these two methods are
grasped as a single linked process, and it
is very natural to assess the LCI of these
two methods employing the average value of lifecycle LCIs of the steel products

Fig. 5 Maintaining of Quality during Regeneration
Gas
phase

Molten
slag

Ti

Ce

Cr

Si

Ca

B

Nb

Zn

Zn

Pb

V

Ni

Mn

Mg
Ca

Al

Sn

Zn

Impurities can be removed
Ca

Mg

Ce

Co

Molten
metal

Mg

Pb

Co

Al

Ce

Pb Co

Nb
Ti
Tibe removed
Nbthat cannot
B Substance
B
Si
Si
Mn
Mn
V
V
Cu
Cu
Cr
Cr
Fe
Fe
Ni Mo
Ni Mo
Sn
Sn

Cu
Mo

Ce
B
Fe

Co

Pb
Si

V
Sn

Cr

Al

Nb

Mn

Cu
Ni

Mo

Iron (Fe)Aluminum (Al)
Magnesium (Mg)
Titanium (Ti)
Source: Modification of the “Report 232_269 by Taketo Hiraki et al” submitted at the 23rd
Annual Conference of Japan Society of Material Cycles and Waste Management (2012)

Fig. 6 Microstructure Control to Impart Diverse Properties

Reheating Roughing Finishing
Process Continuous➡ mill➡ Hot leveler ➡ Online water cooling process
casting ➡ furnace ➡ millChange of rolling
temperatures
Reheating Roughrolling

Further reinforcement of toughness by
the combined use of rolling and cooling
CoolingFinishrollingChange of metallic
structures
Grain growth
Accelerated
Intermediate
Slow cooling:
Recrystallization Drawing
controlcooling: Martensite cooling: Bainite Ferrite/Perlite
More than 800 MPa 600~800 MPa 500~600 MPa
Source: Nippon Steel Monthly (June 2007)

Fig. 7 Production of Steel Products in the World (Steel Products via Blast
Furnace Method and Electric Arc Furnace Method)(million tons)
1,800■ Other methods

1,600■ Blast furnace method

1,400■ Electric arc furnace

method

1,200
1,000
800
600

520

530

290

290

560

610

650

750

820

880

880

870

430

430

360

990

1,210
1,210 1,230 1,210 1,200
1,070 1,100

400
200

310

320

350

370

400

0
Source: World Steel Association

420

450

450

420

430

400

410

470

♦♦♦

Infiltration of LCI Concept for
Steel Products in Japan
In order to diffuse and filter the rightconcept for the LCI of steel products into Japan, JISF is promoting activities
that aim at reflecting the right concepts

based on JIS Q 20915 in the standards
and standard documents in common
use in Japan pertaining to environmental burden assessment. As a result, regarding environmental considerations inbuilding construction, the content of JIS
Q 20915 has been published in the chapter on steel-frame building constructionof the Guideline for the Management of
Building Construction (2019) supervisedby the Minister’s Secretariat of the Ministry of Land, Infrastructure, Transport
and Tourism.
Further, regarding the Environmental Product Declaration (EPD) based on
ISO 14025, JISF has appealed to the Japan Environmental Management Association for Industry so that the LCI calculation methodology based on JIS Q 20915
is subjected to the assessment of EPD,
which led to the enforcement in June2019 of Product Category Rules (PCR)
used as the assessment standard for EPD.
Triggered by this enforcement, it is considered that EPD acquisition for steel
products and secondary products employing steel products will be promoted
in Japan. ￭

e
im
ne
dl
e
sto oalneicl
Lim king c
Ca
re
Co
no
s
l e Iroillion ton
ar: 100 m
u urc
n
o
t
ir
d
a
e
g
Produced using N so
reduc
Lo
sla
*Directly
natural resource: re
ce
ss
a
n
r
Pig iron・DRI*
Scrap from obsolete
30
u
f
P
t
u
B
,
s
b
1 350 million tons
end product
m
uild
lic w
Bla
i
o
illi
n
r
g
k
(external scrap)
s
Mac
con
on
A
s
h
t
S
u
r
i
ucti
ner
eco
tom
to
Steel scrapony
Co ndansobnta
630 million
ine ry pro ile
r
tons
duc
Consumptiontof ferrous
Social steel stock
material
About 32,400 million tons
=4.4 tons/capita
h
C
ls
c
a st
ro
Stee
pro
P
duct
Cru
ct
er
Contain dary produ
steedeSteelnprod locSe
productbileuAutomo1 ctiomill ,810 n output
n
d
inery
n
E
c
ion
Ma h constructio
1,720
tons
duct
ro
g
p
in
d
il
million to
s
u
k
r
B
wo
ns
PublicLifecycle productionof steel products (t)Fig. 11 Concept of LCI Calculation for
Steel Products Based on(∞th recycling)
Recycling
2.00

Environmental burdens occurringfrom steel products (t-CO2)
CO2
0.41
0.33 0.27 0.22
+ CO2 + CO2 + CO2 + CO2 += 0.79(t-CO2/t)+++++
0.66 0.53 0.43
1.00
0.81
Production of steel products (tons)

Fig. 12 Number of Lifecycle andTransition of LCI
2.00

Xpr =2.0 (t-CO2/t)
Xre =0.5 (t-CO2/t)
Y =0.9RR =0.9

1.60
1.20
0.80

n=∞ → LCI= Xpr - RR･Y (Xpr-Xre)= 0.79 (t-CO2/t)

0.00
1

I

I

3

I

I

5

I

I

7

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

I

9 11 13 15 17 19 21 23 25
Lifecycle (numbers)

Fig. 13 Relationship of LCIs between
Basic Equation and Standards’
Equation
LCI= Xpr - RR･Y (Xpr-Xre)

Xpr【 B2 】

p

1,2

Elec

rc
ca
ctri ce ons
Ele furnail ion tm gen
520 oxy e ons
sic ac n t
Ba furn mil io
90

ess s crap

s cra

CO2 emissions in steel
product lifecycle (t-CO2)=

Average value(t-CO2/t)

0.40

Fig. 8 Circulation of Iron and Steel Products in the World (2018)

op

Fig. 10 Concept of LCI Calculation for
Steel Products(Lifecycle Average)

LCI (t-CO2/t)(Fig. 10).
Specifically, the LCI is to be calculated for every repetition of recycling, andas a result, the LCI changes from 2.0 (tCO2) finally to 0.79 (t-CO2). In the Standards, this final value (lifecycle averagevalue) is set as the LCI of steel products,
as shown in Fig. 11. The Standards specify this final value (lifecycle average) as
the LCI of steel products (Fig. 12).
From the concept mentioned above,
the LCI calculation can be expressed using the equation LCI=Xpr-RR･Y (XprXre), but the factor of scrap usage is nottaken into account in this equation. Thatis, it can be said that LCI is identical forsteel products produced via either the BF
method or the EAF method. By the way,
the LCI of steel products is expressed in
the Standards as Xpr=A+B1, -RR･Y(Xpr-Xre)=B2. (Refer to Fig. 13)

tric

arc

【 A + B1 】

ace

furn

slag

Source: Steel Recycling Research(World Steel in Figures 2019 and World Steel Recycling in Figures 2014-2018)- RR･Y (Xpr-Xre)

Fig. 9 LCI in Lifecycle of Iron and Steel Products
Iron ore
Coal

Iron ore-derived
LCI Xpr: 2.0
Pig iron

0* Basic oxygen
Limestone Blast furnace
furnace
Molten steel
yield during
2.0
regeneration ofsteel scrap Y: 0.9
Steel
Scrap scrap-derived Electric arc Refining
furnaceLCI Xre: 0.5
Recovery*0.5 in terms of calculation

Steel productsContinuous
casting

Continuous
casting

Rolling

Rolling

Scrap recycling rate RR: 0.9

Application

Application

Plate

H-shape

Strip coil

Angle

Pipe
Reinforcing
and tube bar

Source of Figs. 9~13:
The Japan Iron and Steel Federation
December 2019 Steel Construction Today & Tomorrow 8

Feature Article: Recycling and Lifecycle Assessment of Steel Products (3)Recycling and the Future of SteelMaterials

by Ichiro Daigo and Pasan Dunuwila
Department of Materials Engineering, The University of Tokyo
Ichiro Daigo: Associate Professor at Department of Materials Engineering, Graduate
School of Engineering, The University ofTokyo. He received Ph.D., M.S. and B.E.
degrees from Kyoto University. He has developed many analytical models and tools andpioneered research in Industrial Ecology. His
achievement has been published in many
academic articles and books.

9 Steel Construction Today & Tomorrow December 2019

Steel Stocks and Future Demand
Several estimation models predicting future demand of steel materials
have been proposed. One of them isthe model termed “Intensity of Use(IU) Hypothesis”, in which IU stands
for the consumption of certain metal per GDP 3). As shown in Fig. 2, thisIU gets an inverted U-shape as the income per capita increases. Many demand forecasts, including the IU hypothesis, have been extrapolated to
the future by analyzing the historicaldemands (flows) in time series. In recent years, the methods based on material stocks that closely adhere to
consumption flows have been proposed and tested.
Lifetime of a product determines
how long the steel materials in which

Fig. 1. Comparison of Primary Energy Intensity of Steel by Country (Japan = 100)
Steel (BOF) 2015
Steel (EAF) 2010160

Steel (BOF) 2010
Steel (EAF) 2005

Steel (BOF) 2005

140
120
100
80
60
40
20

ne
ai

U

kr

SA
U

ia
Ru
ss

ia
In
d

zil
Br
a

d

ce
Fr
an

gl
an

En

na
hi

m
er

C

an

y

a
re
G

Ko

pa

n

0

Ja

Global Warming Countermeasures Taken by Steel Industry
The lowest stabilization scenario of International Energy Agency (IEA), i.e.,
RCP 2.6, allows steel industry to emit
112 billion tons of CO2 within the 40
years starting from 2011 to 20501). In
order to comply with this specified
limit, it would be desirable to transform less-efficient processes to moreefficient ones via the countermeasures
such as renewal of obsolete equipment.
In Fig. 1, the amounts of primary energy consumption to produce a unit
amount of crude steel by blast furnace(BF)-basic oxygen furnace (BOF) andelectric arc furnace (EAF) processes indifferent countries are compared. Japan has the lowest energy consuming
steel industry and this can particularly be attributed to the high energy effi-

ciency in its steel manufacture2).
Process technology developmentsthat stem from the national project termed “CO2 Ultimate Reduction in Steelmaking Process by Innovative Technology for Cool Earth 50(COURSE 50)”, and the European Ultra Low CO2 Steelmaking (ULCOS)
program had been prominent in achieving the said status. Therefore, Japan
must continue discovering new and innovative steel processing technologies
and their dissemination to the world.
On the other hand, from a policy standpoint, one must not cause greater emissions elsewhere while trying to optimize a geographically closed-system,
and instead, policy makers must consider the regional variations in energy
efficiencies.

Primary energy units (Japan=100)

Introduction
The steel industry has produced morethan 1.5 billion tons of crude steel per
year since 2010; for example, it has
produced 1.63 billion tons of crude
steel in 2017. Compared to any other industry that produces metal, environmental impacts associated withsteel production is large owing to thevast resources it consumes. Though theblast furnace process in steel manufacture is highly efficient, future steel production has been questionable in termsof the long-term goals of Paris Agreement which specifically desire a drastic reduction in global greenhouse gas
emissions by the year 2050. Therefore,
from a viewpoint of material life cycle
thinking, this article attempts to foresee the future of steel materials and their
manufacture.

Pasan Dunuwila: Project Researcher, Department of Materials
Engineering, Graduate School of Engineering, The Universityof Tokyo. He acquired his B.Eng., M.Eng., and Ph.D. (Engineering) from Toyohashi University of Technology, Japan. His
research interests primarily lie on the upliftment of economic,
environmental and societal well-being of industries through thetools such as Material Flow Analysis, Material Flow Cost Accounting, and Environmental and Social Life Cycle Assessment.
His works have been published in several reputed journals.

Fig. 2. Conceptual Diagram of IU Hypothesis(IU: intensity of use)
=Resource consumption/GDP

Servitization

Alternative technologies
Technological developments

Resource consumption per capita
Industrialization
GDP per capita

Fig. 3. Trend of Steel Stocks in Japan

Accumulated amount of steel (million tons)

belong to in-use stock. Fig. 3 herein depicts the fluctuations in steel
stock in Japan 4). According to that,of the 1.4 billion tons of steel stock,ca. 1 billion tons belong to the in-use
stock. Infrastructure-stock or infrastock (i.e., the amount steel materials
exist in semi-permanent infrastructure such as slit dams (see Photo 1),
anchor bolts, etc.) constitutes a majorpart of this in-use stock. The rest canbe ascribed to the steel materials thatare left behind, such as steel in obsolete (N.B. obsolete stock (see Photo 2) exists in anthroposphere and thesteel in which is remains difficult tobe collected) and hibernating stocks(N.B. steel in hibernating stock may
be collected in the future as a resultof price increments, etc.) 5). This inuse stock in Japan has been saturated
since 2000, and similar trends havebeen reported in other developed
countries as well 6).
From a material stock perspective,
the curve of the foregoing IU hypothesis can be read as a change of a sigmoidal (S-shaped) curve that saturates
toward a certain point on the particular plot. Materials perform their functions when they are used rather thanconsumed; hence, to better match therelationship between materials andusers, it is advisable to explain thisphenomenon as a time-series change
in the material stock that relies on theamount of material use. Therefore,
using the aforementioned empiricalrule of saturation tendency, “stockdriven model” has been proposed. To

Obsolete stock/landfill/cumulative dissipation

1,600

Permanent structures

1,400

In-use stock

1,200
1,000
800
600
400
200
0
1920

1930

1940

1950

1960

1970

1980

1990

2000

Year

Photo 1 Steel slit dam

Photo 2 Obsolete stock

December 2019 Steel Construction Today & Tomorrow 10

Steel Recycling
Steel is recognized as highly recyclable. But then, how many times cansteel be used repeatedly? In Fig. 4,
we consider that steel materials exist in the states of crude steel, steel
products, use, used scrap, etc., andthe flows that link the processes in the
figure (i.e., Fig. 4) are the transitions
between the said states. Therefore,material flow information is referred
to as “state transition probability.”
Assuming that the current pattern ofuse of steel (material flows) continues forever, a method that evaluates
the average number of repeated uses
had been developed by applying Markov chain model8, 9). Average numberof uses here refers to the number oftimes that steel has been used in domestic products since its initial state(i.e., iron ore), before being exported or dissipated (see Fig. 5). Further,
the exported steel can be dissipated or
re-exported after being used at the exported destination.

11 Steel Construction Today & Tomorrow December 2019

Table 1 Global Crude Steel Demand and Scrap Supply
in 2050 and 2100

(unit: billion tons/year)
2100
Crude steel
Scrap
References
demandsupply2050
Crude steel
Scrap
demandsupply2.1

Pauliuk et al. 2013
Oda et al. 2013*
Morfeldt et al. 2015**

1.0

2.6

2.2

0.9

2.1-2.3***

0.5-0.6

11)

1.8

12)

Not applicable
2.3-2.613)

1.6-1.7* Reference case;** Results of scenario demand stagnation in 2050;*** The results of the three scenarios were denoted as a range

Fig. 4. Conceptual Diagram for State Transitions of Steel-material Flows
ExportNatural Resource

State

Material flow

Blast furnace
Converter

Electric furnace

BF crude iron

BF in house
scrapsRolling

EF crude ironEF steel
products

BF steel
products

Exportbe more specific, Logistic and Gompertz functions had been deployed todevelop the stock-driven models andthereby to forecast the future material stocks 7).
In the models estimating futuresteel demand, the amount of available
scrap is an important factor in quantifying the amount of greenhouse gas
emissions. Table 1 summarizes the recent estimates for the steel demands
and scarp supplies in both 2050 and
2100. Since these estimates are basedon different models and parametersfrom different sources, values tend
to vary. However, Table 1 shows that
scrap itself cannot fulfill the future
demand of steel even in 2100. The ratio of iron sources reduced from ironore is estimated to be at least 50% of
crude steel production in 2050 and
30% in 2100. Presently there are many countries and regions that would
acquire the “developed” status in future; hence steel and scrap would continue to be traded internationally. For
instance, surplus of steel scrap in one
country would effectively be tradedto another country that would have ashortage of iron resources.

Industrial
scrapsManufacturing

Rolling

EF in house
scrapsUse in products (5 categories)
Obsolete scraps
from productsCollection

Landfill

Fig. 5. Conceptual Diagram for State Transitions
Number of transitions
0

Initial state

1

2

3

4

ExportWaste
Use in Japan

In Japan, as shown in Fig. 6, greater
amounts of steel materials and scrap
are exported at the time of state transition, so if simply calculated fromthe material flows, more than 80%of the steel in absorbed state is foundto be exported. Here, assuming thatthe production and consumption patterns of steel materials outside Japan were similar to those within Japan, and based on the flows of steel
in Japan in 2005, it could be estimated that steel had repeatedly been used
ca. five times in Japan. By applying

this model and estimating the global
survival rate over time, it was estimated that about half of the newly produced steel materials would still be inuse even after 300 years10). Therefore,
steel materials will benefit many generations to come by continuing to bereborn as different products throughout the world.
Concluding Remarks
In order to reduce greenhouse gas
emission in the society, reducing thosein the steel industry is a must. Steel

Fig. 6. Flow Chart for (a) Steel and (b) Steel Scrap (2014, Unit: million tons)
(a)

Crude
steel

110.7

Final
steel

95.3

Domestic
steel
demandDomestic
input

39.1

61.5
Steel exports

Prompt scrap 7.3
Exports of finishedproducts 16.5

Ordinary steel 26.1
Special steel 7.1

Exports ofsemifinishedproducts

Home scrap
Prompt scrap
(b)

Used
products

Used
products(Recovered)

11.3
7.3
Obsoleteiron scrap

25.0
46.3

43.3

Exports of
miscellaneous
products

Domestic
consumption

36.7
Exports of scrap 8.1

materials will be in high demand as
they lay foundations for infrastructurethat contribute to the social well-being in developing countries. Thoughsteel is highly recyclable, demand ofwhich in the future cannot be fulfilledby the scrap recycling alone; hence,iron is required to be reduced even till
2100. Also, further developments in
low-carbon steel manufacture are ex￭pected.
References:
1) International Energy Agency: Energy
Technology Perspectives 2014 – Harnessing Electricity’s Potential. OECD/
IEA, Paris, (2014), 376 pp
2) RITE: Energy intensity in iron and steel
sector (January 30, 2018) http://www.
rite.or.jp/system/latestanalysis/2018/01/
Comparison_EnergyEfficiency2015steel.
html3) International Iron and Steel Institute,
Projection 85: World steel demand. International Iron and Steel Institute, Brussels. (1972)
4) I. Daigo, Y. Igarashi, Y. Matsuno, Y. Adachi: ISIJ Int. 47, (2007)1064-1068.
5) I. Daigo, K. Iwata, I. Ohkata, and Y.
Goto: Environ. Sci. Technol. 49, (2015)
8691–8696.
6) D.B. Müller, T. Wang, B. Duval: Environ. Sci. Technol. 45, (2011), 182–188.
7) H. Hatayama, I. Daigo, Y. Matsuno, Y.
Adachi: Environ. Sci. Technol. 44, (2010)
6457–6463.
8) I. Daigo, Y. Matsuno, K.Ishihara, Y. Adachi: Tetsu to Hagane, 91, (2005) 265-273.
9) M. J. Eckelman, I. Daigo: Ecol. Econ.
67 (2008) 265-273.
10) S. Pauliuk: Resour. Conserv. Recycl.
129 (2018) 81–92.
11) S. Pauliuk, R. L. Milford, D. B. Müller, and J. M. Allwood: Environ. Sci.
Technol., 47, (2013) 3448–3454.
12) J. Oda, K. Akimoto, T. Tomoda: Resour.
Conserv. Recycl. 81 (2013) 81– 91.
13) J. Morfeldt, W. Nijs, S. Silveira: J.
Clean. Prod. 103 (2015) 469-482.

Leftovers (hibernating stock)

December 2019 Steel Construction Today & Tomorrow 12

Feature Article: Recycling and Lifecycle Assessment of Steel Products (4)Green Steel Seminar Held

Committee on Environment-friendly Steel for Construction
The Japan Iron and Steel Federation
The Japan Iron and Steel Federation
states how to treat environmental issues
arising from iron and steel production as
one of the major pillars of its operations.
Among the committees to promote measures for the handling of environmental
issues is the Committee on Environmentfriendly Steel for Construction, which
promotes research into environmental
performance assessments of construction
steel products and activities to enhance
understanding of the environmental predominance of these products.
In order to promote understandingof the high environmental performance
demonstrated by steel products-conducive to preventing global warming, building a circulation-oriented society andharmonizing with nature, the committee
has held the “Green Steel Seminar” every year since 2011 in Tokyo for thoseworking in the field of construction. In
November 2019, the committee held its
ninth seminar in Tokyo and plans to holdit for the first time in Osaka in December

with content similar to that in Tokyo.
The ninth seminar was held under themain theme “Recent Measures to Improve
Social Infrastructure and Lifecycle Assessment: High Environmental Performance
Peculiar to Steel Products.” Specifically,four presentations were made centering on

the application of environmental productdeclaration (EPD), the difference between
closed-type recycling and open-type recycling and its reflection in lifecycle assessment (LCA), and LCA methodology
by making the most of the recyclability of￭steel (see the table below).

A List of Presentation Titles and Presentersat the Ninth Green Steel Seminar in 2019
Title
Application of Environmental ProductDeclaration (EPD) in Iron and Steel
Products

Presenter
Masayuki Kanzaki
Director, LCA Center, Sustainable
Management Promotion Organization

Deference between Closed-type Recycling
and Open-type Recycling and Its Reflection in
the Lifecycle Assessment of Iron and Steel
Products

Ichiro Daigo
Associate Professor, Department of Materials
Engineering, Graduate School of Engineering,
The University of Tokyo

Lifecycle Assessment Methodology for Iron
and Steel Products Making the Most of TheirHigh Recyclability

Hidekazu Matsubara
Secretary, Committee on Environment-friendly
Steel for Construction, The Japan Iron andSteel Federation

The Iron Cycle Connects People with the
Earth: Steel’s Environmental Performance andRecent Trends in the Japanese Steel
Industry’s Initiatives to Mitigate Global Warming

Yuki Yamamoto
Chairman, Committee on Environment-friendly
Steel for Construction, The Japan Iron andSteel Federation(Reference: Scenes of the 2018
Green Steel Seminar in Tokyo)

13 Steel Construction Today & Tomorrow December 2019

Feature Article: Recycling and Lifecycle Assessment of Steel Products (5)Introduction of ISO 20915 at the Plenary
Session of SEAISI Annual Conference

International Environmental Strategic Committee
The Japan Iron and Steel Federation
The South East Asia Iron and Steel Institute (SEAISI) held its Annual Conference in Bangkok, Thailand on June
16~20, 2019, to which the International Environmental Strategic Committeeof the Japan Iron and Steel Federation(JISF) dispatched Dr. Shiro Watakabe,
Staff General Manager, Climate Change
Policy Group, Technology Planning Department of JFE Steel Corporation. At
the Plenary Session II of the Annual
Conference, he delivered a lecture that
introduced ISO 20915, which was standardized by the International Organization for Standardization (ISO) in November 2018.
He also joined the panel discussion
held at the Plenary Session II with themain theme of “value creation in steel industry through circular economy mindset.” At this Session, participants madepresentations pertaining to the notionof a circular economy. Mr. Wikrom Vajragupta, the chairperson, gave his impressions-“The notion of the circular
economy differs by both country and organization, and in the situation in which
many ASEAN countries show an excessof imports over exports, yet there are many CEOs who think hard about how tocomprehend the circular economy, but
the presentations from Dr. Shiro Watakabe and other participants show many informative suggestions.”
Following the presentations, there
were questions and answers, where Dr.
Shiro Watakabe stressed that steel products are the most eco-friendly material
from the aspect of lifecycle assessment.
He wrapped-up the session stating-“Itis ISO 20915 that has made it possible toevaluate steel’s recycling effects in a visible method, and I will be very pleased if
the main points of my presentation today

will filter deeply to relevant persons andorganizations in ASEAN nations.”
As the last event at the Session, a30-second video was introduced that was
prepared by JISF under the concept “Actually, Steel is Light” in order to makewell-known the lifecycle assessment ofsteel products, scenes of which were taken up in major steel journals in Japan tosensation. In the Session, Dr. Nae Hee
Han from the World Steel Associationand Mr. Yap Chin Seng, Certification
Authority for Reinforcing Steels, United Kingdom
also appeared
as panelists inaddition to Dr.
Shiro Watakabe.

December 2019 Steel Construction Today & Tomorrow 14

Serial Article: Latest Design of Steel Buildings in Japan (4)GINZA KABUKIZA-Building a High-rise Office Toweron an Open Space of Traditional Kabukiza Theatre
Using a Mid-storey Mega TrussMitsubishi Jisho Sekkei Inc.
Kengo Kuma and Associates
The Kabukiza Theatre in Ginza, Tokyo,
has been reborn as GINZA KABUKIZA,
a complex facility composed of the new
Kabukiza Theatre and a high-rise office
tower, Kabukiza Tower, constructed on
top of the Kabukiza Theatre. It has 29
stories aboveground and four basement
floors.

We have challenged with the difficult
task of recreating a traditional architectural design peculiar to Japanese-stylearchitecture by means of steel structure,
which has led to the successful realisation of a lightly-imaged Kabukiza Theatre while at the same time positively
incorporating advanced structural tech-

nologies. In the switchover section between the theatre and the office tower,
the mega truss, a pivotal device in termsof building structure, was arranged not
only to produce a column-free wide theatre space but also to support the highrise office tower constructed on the theatre (Photo 1 and Fig. 1).

Fig. 1 Section of GINZA KABUKIZA

Office floor

Mega truss
Rooftop garden

Kabukiza gallery

TheatrePhoto 1 GINZA KABUKIZA, a complex facility building where a high-riseoffice was installed on the Kabukiza Theatre
15 Steel Construction Today & Tomorrow December 2019

Carrying on the Historical Spirit of
the Kabukiza Theatre
GINZA KABUKIZA is a reconstruction
project for the Kabukiza Theatre, which
has a history of more than 100 years. The
current reconstruction is its fifth such reconstruction. The former fourth Kabukiza
Theatre, completed in 1950, was designed
by Isoya Yoshida, a celebrated architectin the field of Japanese-style architecture.
Because of some concerns such as growing obsoleteness, insufficient seismic resistance and lack of barrier-free facilities
in the former theatre, it became necessary
to reconstruct it so as to renew these functions. Further, in order to continue to carry on Kabuki, a Japanese traditional performing art, the Kabukiza Theatre needed
to include stable business continuity. To attain these goals, the GINZA KABUKIZA
project was promoted as a complex development project in which an office building
for lease would be established attached to
the Kabukiza Theatre.
One major target pursued in the current
project was that the history of Kabuki performances loved by everyone needed to be
carried into the future, and that new functions that meet the contemporary age needed to be incorporated into the new Kabukiza Theatre. The fourth reconstruction of
the Kabukiza Theatre was considered as acompilation of all reconstructions and repairs so far implemented, and therefore the
newly-opened fifth theatre has fundamentally carried on the concepts behind thefourth theatre.
However, we think it appropriate thatthe newly-opened fifth Kabukiza Theatre
has not simply carried on the former theatre
but has surely succeeded in achieving what
everyone hoped from the former fourth theatre. (Refer to Photos 2 and 3, and Fig. 2)
Expression of Wooden Structures
Employing Steel Structures
The fourth Kabukiza Theatre was a reinforced-concrete structure, and its exterior section was fundamentally finished

Photo 2 Full view of the new Kabukiza Theatre designed by carrying on the former theatrewith concrete. However, in the current
reconstruction project, because the highrise office tower was to be attached to thetheatre, a steel structure was inevitably
adopted as the primary material. Accordingly, even if the new theatre was to succeed the former theatre, it was impossible to adopt identical structural materials
to those used in the former theatre.
Specifically, in the new theatre, the exterior section was mainly finished by
pre-cast concrete (PC) panels fixed tosteel framing. Lightweight glass fiber-reinforced concrete was used as the bracket complex, and aluminum members wereused for the rafters because the theatre roof
had warp and thus the dimension of thestructural members applied differed. In thisway, suitable members were selected forthe right applications.
There arose some fears that the adoption of steel structure would cause thechange in image of reinforced concretestructured former theatre. However, if all
structural members used for the new theatre were to be produced by means of theconcrete forming method, the construction costs would have soared, and it was
further considered that the completed
new theatre would not be able to present
such a lightweight structural image.
In addition, the architectural design ofthe Kabukiza Theatre expresses the Japanese traditional wooden architecture, andthus the steel frame+PC panel system adopted for the new theatre, rather than thereinforced concrete system for the former theatre, seems the right choice. Because the wooden structure is assembled
by combining every structural piece one
by one, it is supposed that the engineers
engaged in the construction of the thirdand fourth theatres by the inevitable use ofreinforced-concrete structures faced many difficulties. By such a meaning, just because the difference of the structural materials between the new and former theatres
was supported by the maximum use ofcontemporary technologies, we surely believe that the carrying over of the architectural concepts from the former theatres tothe new theatre was successfully attained.

Fig. 2 Section of Theatre Seat Section

Profile line of former theatre

Photo 3 Theatre seats prepared by carrying on the design of the former theatre
December 2019 Steel Construction Today & Tomorrow 16

17 Steel Construction Today & Tomorrow December 2019

Fig. 3 X-direction Framing Elevation

GL

23,210133,220
5,050 8,850 6,000 4,900 3,750 7,500 6,350
6,130 4,250 4,250 4,250 4,250 4,600 4,200 4,200 4,200 4,200 4,200 4,400
4,200 5,000 3,750
4,250 4,250 4,250 4,250 5,000 4,200 4,200 4,200 4,200 4,200 4,200
5,800

Seismic Design
The significant subject in the structural design stage was the influence on seismic resistance of the column arrangementin which most columns at the south side
(theatre front side) are supported using themega truss in order to treat south-north direction seismic vibrations. While the columns at the north side of the high-rise
tower are installed on the ground, those at

Photo 4 Mega truss structure provided as the switchover structure between the theatre and high-riseoffice tower

740

Switchover from Lower Theatre
Floors to Upper Office Floors
In the reconstruction project for the fifth
Kabukiza Theatre, a steel structure wasnecessarily adopted in order to realise thecomplex facility composed of the theatre
and the office tower. In the theatre section,
various devices were incorporated to recreate the wooden architecture using thesteel structure. Because the high-rise office tower is right above the theatre, a mega truss system was introduced between
the theatre and high-rise tower sections.
Specifically, two mega trusses were arranged in the fifth and sixth floors in theswitchover section between the theatre
and the high-rise office tower to provide
the column-free atrium in the four layersof the theatre section and also to support
ten columns installed on the south side
(theatre front side) of the high-rise tower.
(Refer to Photo 4)
Further, in order to smoothly transfer
the load from the mega truss to the ground,a wall beam mechanism was provided in
the third and fourth basements to support
the mega truss, through which the loadfrom the mega truss is dispersed and transferred to the ground.
In the fifth storey of the mega truss
floors, Kabukiza gallery and rooftop garden were provided, and in the sixth storey, machine rooms were provided. In
this way, the MEP equipment and otherfacilities used by both the theatre and thehigh-rise office tower could ingeniously
be arranged in the mega truss floors located between the theatre and high-rise tower sections. In the circulation plan for theentire building, an office tower entrance
was arranged separately from the theatre
entrance, and those working in the office
tower change from the elevator for use
for the lower floors to the elevator for thehigh-rise office tower at the seventh floor.
The pit for these elevators could be fitted
into the mega truss floor.
In terms of the architectural design,
MEP, structure and other aspects involvedin the GINZA KABUKIZA building, we
think that the system switchover between
the theatre and the high-rise office has successfully been put in effect.

29FL
28FL
27FL
26FL
25FL
24FL
23FL
22FL
21FL
20FL
19FL
18FL

Bucklingrestrained brace(LY225)

17FL
16FL
15FL
14FL
13FL
12FL

Oil damper

11FL
10FL
9FL
8FL
7FL
6FL

Mega truss(SA440)5FL

Bucklingrestrained brace(SN490)

4FL
3FL
2FL
1FL
B1FL
B2FL
B3FL
B4FL

Wall beam tosupportmega truss
9,380
X0

9,600 6,400 6,400 6,400 6,400 6,400 6,400 6,400 6,400 7,850
78,030
X2
X3 X4 X5 X6 X7 X8 X9 X10 X11 X12
X13

the south side are supported by the mega
truss. To that end, repeated examinations
on seismic resistance were made employing three-dimensional and other approaches to confirm the seismic safety of the entire building. Particularly for the high-riseoffice tower, a hybrid response-controlled
system was adopted by arranging sets ofboth buckling-restrained braces and viscous oil dampers. (Refer to Fig. 3)
The buckling-restrained braces werealso inserted under the mega truss. As
mentioned above, in the current reconstruction project, a structural design was
introduced in which the framing structures
were clearly divided into those used forthe theatre and those for the high-rise office tower. In the low-rise section, because
the theatre is located there and many complex frames are applied there, the design
was made so that framing deformation isfundamentally suppressed to a minimum
level and the framing shows elastic behaviors. That is, the design was made so thatthe structural section under the mega truss
does not cause much plasticization. On theother hand, in the high-rise tower section,
the main beam was designed so that someplasticization is allowed to occur during
great earthquakes. Well-organized structural designs are adopted for both the theatre and the high-rise office tower.
Mega Trusses to Support
High-rise Tower
The mega truss has a span length of 38.4
m and a height of 13 m, and two trusses
are arranged at the south side of the highrise tower (the front side of Kabukiza Theatre). The long-term axial load to be borneby the two mega trusses amounts to 9,000

tons, the highest class of mega trusses applied in high-rise buildings in Japan. Highstrength steel (SA-440) is applied for all ofupper chords, lower chords and diagonal
members having a box section of 900×900
mm. (Refer to Photo 5 and Fig. 4)
Because the mega truss is a large-size
member, it is difficult to lift-up the truss
assembled on the ground. Accordingly, it
was assembled by the use of temporary
column while controlling its level by theuse of hydraulic jacks (Photo 6). The structural section just beneath the mega truss isthe trap cellar of the theatre, and thus it
was forecasted in the current reconstruction project that, if the temporary column
was installed in the theatre as it is, there
would arise some obstacles in the following construction of the theatre. To that end,
it was necessary to remove the temporary
column quickly after the finish of the installation of the mega truss, which however required special devising in the frame
installation above the mega truss.
When the framing above the mega truss is to be installed while supporting the frame load by the use of the mega

truss, the mega truss would cause deflection as the load to be borne by it increases, and at the same time the deflection of
the frame above the truss would increase.
That is, the extra load would be added tothe mega truss, which would lead to an irrational design of framings to be installed
above the truss.
To prevent such adverse effects fromoccurring, hydraulic jacks was fitted into
the column base on the truss upper chord,and framing installation progressed while
controlling the vertical displacements ofthe framings above the mega truss (Photo 7). That is, the following process was
adopted: as the assembly of building
frames on the mega truss progressed, themega truss deflected due to the increasing weight of those frames to cause deflection of the frames being installed →the frame deflection was corrected by theuse of jacks to maintain the level frame installation → then these processes were repeated to install subsequent frames levelly.
The high-rise tower section was constructed while returning the building frames to alevel state as if the frame above the mega
truss were sitting on the ground.
Hurdling of Application Limits for
Steel Structures
Since both Kabuki actors and fans have
exceptional feelings for the Kabukiza
Theatre, how they would evaluate the
newly-opened theatre was our primaryconcern. But it has come to be highly reputed. In many cases, people first feel asense of incongruity in a newly built the-Photo 5 Mega truss with a span of 38.4 m and aheight of 13 m and manufactured
employing high-strength steel SA440

Fig. 4 Details of Mega Truss Steel Framing

Photo 6 Hydraulic jack used to secure level
assembly of frames○: SA440C high-strength steel
Unmarked: SN490B rolled steel for building structure

Photo 7 Measurement of displacement offrames during installation
December 2019 Steel Construction Today & Tomorrow 18

atre, but gradually become accustomed
to it. The new Kabukiza Theatre, however, has won such a high reputation eversince its completion. We think it uncommon that the new theatre has received
such a high public estimation just fromthe stage of opening of the theatre.
Kabuki actors, fans and other related persons individually have their own
image of the Kabukiza Theatre deep intheir heart. We now feel happy that we
succeeded in reconstructing the theatre
to such an extent that it satisfies all ofthem. The Kabuki audience, meanwhile,
consists of a great many regular patrons
having an intimate knowledge of the former fourth Kabukiza Theatre. The current fifth theatre resembles its predecessor so closely that merely shifting theposition of the theatre’s souvenir shops
to the reverse side is throwing some ofthe patrons into confusion.
Moreover, not a few people are unsurethat the current theatre was reconstructed, still believing that the fourth theatre
was left intact, with only a high-rise tower added behind. To that end, there areeven cases where we have been asked if
it is true that we entirely tore down theold theatre building for reconstruction.
We had a hard time, yet the reconstruction project was exceptionally gratifying.
We believe that we have done a good job,by taking advantage of the quality of thejoint design team of Mitsubishi Jisho Sekkei Inc. and Kengo Kuma and Associates.
The column-free space provided in thetheatre and the mega truss adopted in theconstruction of the new Kabukiza Theatre have become available only with theflexible application of steel structures. At
the initial stage of design, we had somefears about the occurrence of vibrations
and noises caused by the use of steel structures, but these concerns were fully solved
capitalizing on contemporary architectural technologies. The successful completion of the current reconstruction project is owed greatly to the maximum use ofhigh performance that steel can offer andthe all-out effort to hurdle the application
limits for steel structures. We accept thatthe current project can be positioned, in asense, as a model solution in the application of steel structures. (Refer to Photo 8)

Outline of GINZA KABUKIZA Project

Location: Ginza, Chuo-ku, Tokyo
Project owner: KS Building Capital Specific Purpose Company, Kabukiza Theatre
Development: Shochiku Co., Ltd. (trustee)
Main applications: Office, theatre, shop and parking lot
Area: Site area-6,995.85 m2
Building area-5,905.62 m2
Total floor area-93,530.40 m2
Material: Aboveground-Structural steel
Underground-Structural steel and reinforced concreteFoundation-Reinforced concrete
No. of stories: Four basements, 29 storeys aboveground, two-storey penthouse
Maximum height: 145,500 mm
Design: Mitsubishi Jisho Sekkei Inc., Kengo Kuma and Associates
Structural design: Mitsubishi Jisho Sekkei Inc.
Construction: Shimizu Corporation
Design term: January 2008 to September 2010
Construction term: October 2010 to February 2013

Photo courtesy

Mitsubishi Jisho Sekkei Inc.
Kengo Kuma and Associates
Taisuke Ogawa/Taisuke Ogawa Shashin Jimusho
Mitsumasa Fujitsuka/Helico
Shochiku Co., Ltd.
Kabukiza Theatre

Photo 8 Traditional tile roof of Kabukiza Theatre and vertically-narrow spaced lattice exterior of
Kabukiza Building of GINZA KABUKIZA completed by optimized use of steel structure

STEEL CONSTRUCTION TODAY & TOMORROW
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