No. 46 December 2015

STEEL CONSTRUCTIONTODAY & TOMORROW

http://www.jisf.or.jp/en/activity/sctt/index.html【 k a n 】
“環 (kan)” in Japanese, or ring or circulation in English

In terms of LCA (a methodology for assessing the environmental
impact of a product at all stages of its service life), steel’s
performance is predominant-steel is repetitively recycled forreuse in a circulation ring. This issue, No. 46, covers the
topics relating to LCA and steel’s high environmental friendliness.

Special Feature: LCA and Recycling of Steel Products
1 Examination of LCA for

Steel Structures in the Fieldof Construction

2 Examples of and Future Tasks
for LCA Models in Japan

5 LCI Assessment Methodology
for Incorporating the Effect ofSteel Product Recycling

9 Material Stock and the End-of-life Recycling Rate of Steel

Published Jointly by

The Japan Iron and Steel Federation

13 Steel Construction Products
Conducive to Supporting an
Eco-friendly Society

17 Steel Construction

Japanese Society of Steel Construction

Technologies in Japan

Back cover JISF Operations

Special Feature: LCA and Recycling of Steel Products

Examination of LCA for Steel Structuresin the Field of Construction
Committee on Environment-friendly Steel for Construction, The Japan Iron and Steel Federation
In Japan, studies are underway regarding the
introduction of LCA (a methodology for assessing the environmental impact of a product at all stages of its service life) into thebidding system for domestic public works
projects and into green procurement regulations (Act to Promote the Procurementof Eco-Friendly Goods and Services by theState and Other Entities).
In concert with this, the Committee on
Environment-friendly Steel for Construction of the Japan Iron and Steel Federation
has started initiatives to establish methods ofassessment that are relevant to the high environmental performance of steel products,
such as taking into consideration the mitigation of environmental impacts offered by
the rational use of blast furnace and electricarc furnace methods in recycling and by theuse of high-performance steel products. Further, the committee is promoting activities
toward the wider application of eco-friendly
steel construction products. Additionally, inorder to promote a deeper understanding of
the high environmental performance of steel
structures, the committee annually holds its“Green Steel Seminar” targeting those working in construction.
As part of this effort, the Japanese Society of Steel Construction established in 2010
a “Working Group to Examine the LCA of

Steel Structures in Construction,” composedof leaned persons, steelmakers and steel users. The working group collects information, studies LCA methodologies in the fieldof construction, and examines how to apply
LCA to steel products. In 2014, the working
group organized its study results.
The results of the working group’s activities were reported at the 4th Green Steel
Seminar under the theme “Recent Initiatives
toward the Improvement of Social Infrastructures and Life Cycles-the Predominance in
Recycling of Steel Products in Construction.” This event was held by the Committee

Fourth Green Steel Seminar held in November 2014

1 Steel Construction Today & Tomorrow December 2015

on Environment-friendly Steel for Construction on November 27, 2014 (refer to the tableand photo below).
The current issue, No. 46, of Steel Construction Today & Tomorrow introduces apartial outline of the activity results reported
at the Green Steel Seminar; at the same time,it describes the initiatives toward global environmental preservation promoted by the Japanese steel industry.
￭

A List of Lecture Themes and Lecturers at 4th Green Steel Seminar
Keynote lecture:
Recent Trends and Future
Directions Involved in LCA

Matsunori Nara, Dr. Eng.
Professor, Department of Computer andMedia Engineering, Tokyo University of Science, Suwa

Methods to Treat Structural
Steel Members Left Behind

Dr. Yoshikazu ShinoharaGroup Leader, Eco-energy Group, National Institute forMaterials Science

Introduction of LCA Approaches
to Take Account of Recycling
Effects of Steel Products andSimulation Examples

Tomohisa Hirakawa
Vice Chairman, Committee on Environment-friendly Steelfor Construction, The Japan Iron and Steel Federation

Assessment Approaches forEnvironmental Influence
Caused by Use of Steel
Products

Dr. Minoru Fujii
Senior Researcher, Eco-city Systems Research Program
Project Leader, Environmental Urban Systems Section,
Center for Social and Environmental Systems Research,
National Institute for Environmental Studies

Life Cycle Assessment (LCA)

Examples of and Future Tasks for LCA
Models in Japanby Matsunori Nara, Dr. Eng.
Professor, Department of Computer and MediaEngineering, Tokyo University of Science, Suwa
LCA at a Glance
The standardization of life cycle assessment(LCA, or assessment of the environmental
impact of a product at all stages of its servicelife) started in 1993 at the International Organization for Standardization (ISO). In 1997,
the ISO published: ISO14040: Principles andFramework for LCA, ISO14041: Goal andScope of Definition and Inventory Analysis
and ISO14049: Examples of How to Apply
ISO14041.
In Japan, the Life Cycle Assessment Society of Japan, a joint industrial-public-academic organization, was established in 1995
to promote LCA studies. In 2007, the Japanese Society of Steel Construction initiatedstudies of LCA for steel products and steel
structures. Triggered by the establishment
in 2009 of the Act to Promote Procurementof Eco-Friendly Goods and Services by theState and Other Entities (Ministry of the Environment), the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) began
an examination of LCA for public works.
Currently, while a number of theoretical studies and case studies on LCA are underway,
efforts are also being directed toward the collection of inventory data.
In the construction industry, a multi-layered system is in place to receive and construct individual projects involving multiple
companies, and this has made it difficult tocollect inventory data. However, this problem has been solved through joint research
between MLIT’s National Institute for Landand Infrastructure Management and the Japan Society of Civil Engineers; as a result,
it is now possible to conduct inventory analysis (LCI: life cycle inventory) even for public works projects. LCI is a hybrid-type of inventory data that is prepared by the combined
use of input out tables (matrix of production
and transactions by industry) and accumulated data; its application allows implementation of LCA for materials, construction methods and structures by setting CO2 emissions
and expenditures as assessment parameters.

Matsunori Nara: After graduating from the Departmentof Architecture and Building Engineering, Tokyo University of Science in 1975, he served as a lecturer of thatdepartment in 1990. He then became a professor of Department of Mechanical Engineering, Tokyo University of
Science, Suwa in 2002 and assumed his current position
as a professor of the Department of Computer and MediaEngineering, Tokyo University of Science, Suwa in 2014.

Tasks Involved in LCA Relevant to the
Recycling of Steel Products
Certain difficulties remain in implementing
LCA in the construction field. Among thespecific issues that have been pointed out are
the restricted range of LCA to the life stages of materials manufacture and construction;
the priority placed on CO2 emissions and theinsufficient assessment of other environmental impacts (relating to trade offs, integrated
parameters, etc.); and the non-quantificationof the effects produced by the repeated recycling of steel products and other materials.
It is probably thought as only natural thatsteel products, after reaching the end of theirservice life, are repeatedly recovered as scrap
and are recycled again and again. Actually,
however, in contrast to the performance ofother materials, this characteristic of reusability-which reduces the material’s environmental impact-is peculiar to steel anddeserves special mention. In other words,
while most materials are recycled in a cascading flow, steel and other metallic materials can be horizontally recycled.
Another advantage that steel recycling has
over other products is that steel can easily beseparated from other materials using magnets
in the recovery process. In cases when metals other than steel are used in combination
with different metals or materials, it is often
difficult to separate these metals and materials, and there are cases when recycling cannot proceed smoothly.
In the field of construction, steel products
are independently used in the construction ofsteel-frame structures and are frequently used
together with concrete in reinforced-concrete(RC) structures. However, even in RC structures, the steel and concrete can now be easily separated and recovered when the service
life has expired. Compared to other metallic
materials, steel is recognized as being easily recycled.
Be that as it may, there is currently no established method for appropriately assessing
the excellent environmental characteristics

of steel products-i.e. that steel is a highly
recyclable material that allows for repetitive
recycling. Eco Mark and other environmental labeling programs, along with the Act on
Promotion of Procurement of Eco-Friendly
Goods and Services, support the procurementof these goods and services by appropriately
assessing their environmental effect with thegoal of creating societies with a smaller impact on the environment.
However, the environmental impact assessment techniques currently in use cannot
assess the effect produced by repetitive recycling. The current techniques cannot distinguish between the environmental performance of materials that can be recycled only
once and those that can be recycled multiple
times. The average person likely understands
that, as the number of times of recycling of amaterial is increased, its resource-saving effect increases and its environmental impact
becomes less. In light of this, it is hoped thatan environmental impact assessment technique will be developed in the future that willtake into account both the ease and potential
multiplicity of recycling.
On the other hand, in order to promote thehigh environmental performance that is peculiar to steel products, it will be necessary toaccumulate data confirming the predominant
recyclability of steel products and to raise social awareness about this aspect of steel. The
iron- and steelmaking processes operated by
the Japanese steel industry are regarded as
being world leaders in having a low environmental impact. However, this does not meanthat efforts to further reduce the environmental impact of these processes are complete,
as there is still much room for continued improvement.
An effective step in this direction is topursue the production of zero-emissions steel
that consumes fewer resources and energy,
improves waste water and exhaust gas purification, and discharges less waste. Meanwhile, the consumption of non-renewable(exhaustible) resources and energy is not alDecember 2015 Steel Construction Today & Tomorrow 2

ways directly tied to an increase of environmental impact or to a deterioration of sustainability, but there are definitely cases in which
the appropriate use of exhaustible resources
can mitigate global environmental outcomes.
Case Study of LCA in Bridge Construction
An LCA case study was made of the old
Showa Bridge, a highway bridge constructed where National Route 122 spans the Tone
River. The LCA was conducted based on thetechnique reported in the “Development ofEnvironmental Impact Assessment Technology for Life Cycles of Social Infrastructure”

by the National Institute for Land and Infrastructure Management (NILIM) of the Ministry of Land, Infrastructure, Transport andTourism. The main goal of this study was toattempt a lifecycle assessment of an actual
structure using the NILIM technique and tocompare CO2 emissions at different stages in
the life of a steel bridge.
Trial calculations of CO2 emissions weremade for two lifecycle cases: a lifecycle that
conforms to the repair history of the actual
bridge (case 1) and a virtual lifecycle that reflects current social needs and current technological levels (case 2). In case 1, the CO2
emissions were calculated based on the actu-

al service period (44 years) of the old Showa
Bridge. In case 2, the CO2 emissions were
calculated assuming the construction of asimilar bridge modeled on the old bridge andsetting 200 years as the target service period(rebuilt 100 years after construction). Fig. 1
shows the CO2 emissions for the case 1 lifecycle, and Fig. 2 for the case 2 lifecycle.
The comparison of CO2 emissions at every life stage of the steel bridge demonstrated that the total emissions at both the design/
construction stage and the demolition/recovery stage accounted for more than 90% of thetotal lifecycle emissions in both cases—suggesting that decision-making regarding the

Fig. 1 CO2 Emissions in 44-year Life Cycle at Old Showa Bridge (Case 1)
Change in CO2 emissions in life cycle (44 years) of old Showa Bridge

CO2 emissions (accumulated total, tons)

Demolition

Repainting

Repainting

Pavement replacement

Pavement replacement

Repainting
Repainting

Floor slab repair
Construction

Pavement replacement

Pavement replacement

Lapse of years

Fig. 2 CO2 Emissions in 200-year Life Cycle at Model Bridge (Case 2)

CO2 emissions (accumulated total, tons)

Change in CO2 emissions in life cycle (200 years) of model bridge
Pavement
replacement

Pavement
replacement

Pavement
replacement

Construction

Repainting

Demolition/
construction

Pavement
replacement

Repainting

Lapse of years
3 Steel Construction Today & Tomorrow December 2015

Pavement
replacement

Pavement
replacement

Pavement
replacement

Pavement
replacement

Pavement
replacement
Pavement
replacement

Pavement
replacement

Demolition

Pavement
replacement

Repainting

Repainting

selection of materials and construction methods has a strong effect on LCA results. Similarly, while the CO2 emissions of the maintenance stage were minimal in both cases, theCO2 emissions of the demolition/recovery
stage equaled 25% of the design/construction
stage emissions, making it clear that the demolition/recovery stage has a large environ-mental impact. (Refer to Figs. 3 and 4)
In order to reduce the CO2 emitted during
the lifecycle of a structure, it will be necessary to pay due consideration not only to reducing the environmental impact caused by
the production of the construction materials
used, but also to making easy the recovery of
structural members during demolition and to

Fig. 3 Ratio and Tonnage of CO2 Emissions in 44-year Life Cycle by Life Stage at
Old Showa Bridge (Case 1)
Demolition/recovery
1717.3
Demolition/recovery (18%)÷Design/construction (72%)=25.0%
18%
Maintenance1003.5
Design/construction
10%5856.972%

Fig. 4 Ratio and Tonnage of CO2 Emissions in 200-year Life Cycle by Life Stage atModel Bridge (Case 2)
Demolition/recovery
3435.5
Demolition/recovery (19%)÷Design/construction (74%)=25.7%
19%
Maintenance1227.1
Design/construction
7%13770.5
74%

Fig. 5 Striking a Balance between Environment, Cost and Society

LCA

Lifecycle
assessment

MFCA

Material ﬂow
cost analysis

CSR

Corporate social
responsibility

taking account of recyclability after recoveryof the materials used.
Future Directions in LCA
It is considered that in the future the environmental performance of materials will be assessed with a view to “sustainability.” Thebasis for assessing sustainability should consider the use of non-renewable resources andrare materials, long-term planning that takes
into account multiple generations, and futureforecasts regarding environmental change.
Similarly, the environmental performance ofsteel products will have to be assessed by taking these factors into account.
In addition, it is indispensable for the
product to be assessed from the aspect of
economic performance. At the market, theproduct is required to offer not only the highenvironmental performance but also the economic advantage such as reduction of internally and externally uneconomic products.
As regards the economic performance, theenvironmentally economic performance of
products can be assessed by means of the material flow cost analysis (MFCA) that aims at
reducing the generation of internally uneconomic materials such as the wastes called thenegative product. (Refer to Fig. 5)
As stated earlier, in order to strategicallyassess environmental impacts, it is requiredthat business operating processes be transparent, that assessment results be scientificand easy to understand for anyone, and thatthe opinions of the people be fully reflected.
From the perspective of making environmental influences easier to understand, LCA is effective and the quantified environmental performance supports of better understandingof LCA by the people. Moreover, the MFCA
covering the entire life cycle of the productcan serve as a useful means with which theeconomic performance of products is built-in
into the economic system.
Accordingly, as far as steel products areconcerned, their performance should be explained in terms of LCA economics. Morespecifically, the high level of environmental performance of steel products should beindicated with stress placed on their uniqueadvantage: the possibility of repetitive recycling and the resulting cost down. To attainthis goal, it will be essential to establish LCA
techniques that appropriately assess the environmental performance of steel products, toobtain social consensus by standardizing thetechniques in JIS and ISO and, at the sametime, to continuously promote studies on theeffective use of these techniques.
￭

December 2015 Steel Construction Today & Tomorrow 4

Steel Product Recycling

LCI Assessment Methodology for
Incorporating the Effect of Steel
Product Recycling

by Tomohisa Hirakawa
Vice Chairman, Committee on Environment-friendly Steel for Construction, The Japan Iron and SteelFederation
Table 1 Difference in Recycling by Material
Material recycling

The method for calculating the unit CO2
emissions of steel products (LCI assessment) introduced in this article is based on
the methodology proposed by the World
Steel Association (worldsteel) [See: “worldsteel (2011)1): LCI (life cycle inventory) assessment methodology”]. This methodology
clearly distinguishes two types of recycling
systems: open recycling and closed (horizontal) recycling.

Horizontal recycling

Of recycling systems, the horizontal recycling denotes the process
in which a material after recycling is used for the application similar
to that before recycling.
Ex.: Steel frame, reinforcing bar (structure) → Steel frame, reinforcing bar (structure)

Cascade recycling(Down cycle)

Of recycling systems, the cascade recycling denotes the process inwhich a material after recycling is used for the application different
from that before recycling.
Ex.: Concrete (structure) → Concrete (roadbed material)

Thermal recycling

In thermal recycling, scrap, wastes and other materials are incinerated torecover thermal energy, or called the thermal recovery system.
(Distinguished from material recycling)
Ex.: Lumber, plywood → Fuel source

Fig. 1 Circulation of Iron and Steel Products in Japan (FY2010)

od

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46.10

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Consumption
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of steel product.11
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(unit: million tons)
Source: The Japan Iron and Steel Federation
5 Steel Construction Today & Tomorrow December 2015

Fig. 2 Concept of End-of-Life Approach (worldsteel 2011)

Virgin material
Recycled material
Scrap remelting
Use phase

Redistribution ofenvironmental value

Disposal
Avoided production

Production

Use

End of life

Deduction ofenvironmental value

Fig. 3 Relation between Blast Furnace Method and Electric Arc Furnace Method

Iron ore
Blast furnace method
Coal

Electric arc
furnacemethod

Blast furnace

Limestone

Basic oxygen
furnaceBlast
furnacemethodScrap

Open recycling refers either to recycling
systems wherein the recovered material is recycled to produce new types of products or
it refers to recycling systems (cascade recycling and thermal recycling) wherein the peculiar physical properties of a material are
altered. On the other hand, closed recycling
denotes recycling systems in which the phys-

Electricarc
furnacemethodElectric arc furnace

ical properties of the recycled products do
not change and the recycled products can bereused for the same applications as before.
For example, steel structural members
such as steel frames and steel-reinforcing
bars can be recycled and reproduced as newsteel products. The basic physical propertiesof these recycled products show no change

and the products themselves can be usedagain for the same applications. That is, it
can be said that steel products are amenable
to horizontal recycling. (Refer to Table 1).
The value of materials used to manufacture steel products that are suitable for horizontal recycling never decreases, even whenthe materials are subjected to repetitive recycling. And, as these materials circulate
through society, they are almost never discarded and never become waste. Fig. 1 shows
the state of steel products circulating in Japan.
Concept of LCI Assessment That
Considers Recycling Effects
While many approaches are taken in LCI assessment methodologies, worldsteel proposes a methodology based on the “End ofLife (EoL) Approach.” In this approach, on
the assumption that steel products are suitable for horizontal recycling, the greenhouse gas emissions produced by the manufacture of a steel product are redistributed
to the next-generation product, thereby levelling the environmental impact imposed at
the production stage. That is, when assessing environmental impacts of steel products,
it is a comprehensive approach that eliminates the distinction between products to be
produced by melting iron ore (blast furnace
products) and products to be produced primarily by melting scrap (electric arc furnace
products). Fig. 2 shows the concept of worldsteel’s comprehensive approach.
Relation between the Blast Furnace
Method and the Electric Arc Furnace
Method in the Production of Iron andSteel Products
Two methods are used in iron- and steelmaking: the blast furnace (BF) method and theelectric arc furnace (EAF) method. The BF
method denotes a process in which pig iron(molten iron) that is produced in a blast furnace, using iron ore as the main raw material, is then refined in a basic oxygen furnace
to produce steel. The EAF method denotes aprocess in which used steel materials are remelted typically in an electric arc furnace toproduce steel, or in which scrap steel is converted into renewed steel in an electric arc
furnace.
Fig. 3 shows the relation between the BF
method and the EAF method. As shown in
the figure, iron ore is not the only material
used as a raw material in the BF method, andthe materials applied in the EAF method are
not restricted to scrap steel. For example, it iscommon in the BF method to use scrap steel(amounting to about 10~20% of the total load
December 2015 Steel Construction Today & Tomorrow 6

of raw materials used as iron sources), andthere are cases in which reduced iron is used
as a source material in the EAF method (refer
to Fig. 3). That is, it can be understood thatboth the BF and EAF methods can be usedrationally to produce iron and steel products.
Calculation Method for LCIEoL That
Takes Recycling Effects into Account• External Scrap LCI
In calculating LCIEoL, the LCI of external
scrap (scrap LCI) is conceived as corresponding to this statement: “Y kg of steel productis produced from 1 kg of external scrap employing the EAF method, and this scrap LCI
take overs Y kg worth of LCI of steel product produced employing the BF method.” Y
indicates the production efficiency (yield) at
the stage when steel products employing the
EAF method are produced. When the LCI ofsteel products produced by the EAF method(theoretical value assuming 100% use of external scrap) is defined as Xre, and the LCIof steel products produced by the BF method (theoretical value assuming 0% use of external scrap) is defined as Xpr, the scrap LCI
can be defined as follows.
Scrap LCI＝Xpr・Y−Xre・Y = (Xpr−
Xre)・Y --- ①• Calculation Equation for LCIEoL
The LCIEoL of steel products can be conceived as the total LCI obtained by deducting the scrap LCI-according to the external scrap recovery rate (RR)-from the steel
products LCI (X) that does not take accountof recycling efficiency, and further adding(redistributing) the scrap LCI-according to
the steel scrap application ratio (S)-during
the production of steel products. When organizing the above, the following equation is
obtained. The definition of each element usedin the equation below is shown in Table 2.
LCIEoL=X−RR・Scrap LCI+S･Scrap LCI--- ②
From ①, because scrap LCI=(Xpr−
Xre)･Y:LCIEoL= X−(RR−S)・(Xpr−Xre)･Y --- ③• Calculation Examples for LCIEoL
Assuming the case for ordinary steel plates,a trial calculation of the LCIEoL of steel
plates was made by giving the assumed value shown in Table 3 for each element used
for the LCIEoL equation shown above. As a result, LCIEoL reached 0.76 (kg-CO2/kg). When
comparing LCI (X) that does not take account of the recycling effect, while LCIEoL
in the BF image decreased: 0.76/1.97→a de-

7 Steel Construction Today & Tomorrow December 2015

crease by 62%, that in the EAF image increased: 0.76/0.66→an increase by 62%.
These calculation results can be considered
attributable to the fact that, irrespective ofwhether BF products or EAF products are involved, the environmental impact is levelledby thinly redistributing the greenhouse gas
emissions caused by the production of nextgeneration products that were originally produced from iron ore.
LCI Calculations That Fully Incorporate the High Recyclability of Steel
Products
In the civil engineering and building construction fields, the main approach to LCI
calculations currently in use is to assess theenvironmental impact imposed by steel products only from the stage of raw materials procurement and production to the point of their
shipment (cradle to gate), which is basedon the life stage boundary shown in Fig. 4.
Because this approach does not assess LCI
through the entire life of steel products, it isessential to employ an approach that takes
the recycling effect (end of recycling, etc.)
into account.
Currently, the Japan Iron and Steel Federation, under a tie-up with the World Steel Association, is promoting the incorporation into
ISO standards of the above-mentioned approach to LCI calculations that takes the recycling effect into account. Further, in accordance with this approach to LCI calculation,

Table 2 Definition of Respective Elements in LCIEoL Equation
Element in equation

Definition

LCIEoL

Steel product LCI (kg-CO2/kg) that takes account of recycling effect;
System boundary for LCI calculation of steel products is set to coverproduct life stages from raw material procurement, production andshipment to external scrap recovery, intermediate treatment, recycling
process and scrap LCI; EoL: End of life

Scrap LCILCI of external scrap (kg-CO2/kg); External scrap denotes steel scrap
recovered from end-of-life end-use product and does not include
process scrap and steel shop scrap

X

Steel product LCI (kg-CO2/kg) that does not take account of recycling
effect; System boundary for LCI calculation of steel products is set tocover product life stages from raw material procurement to production
and shipment (cradle to gate)

Xpr

LCI (kg-CO2/kg) of steel product produced by blast furnace method: On
the premise of 0% in scrap application rate

Xre

LCI (kg-CO2/kg) of steel product produced by electric arc furnace
method: On the premise of 100% in scrap application rateRR

RR (recycling rate) in calculation equation for LCI EoL proposed byworldsteel; In its report, RR is shown using the ratio (kg/kg) of theexternal scrap recovery amount (kg/y) to the external scrap generation
potential (kg/y); RR does not cover yielding in steelmaking employing
recovered external steel scrap

Y

Production efficiency in electric arc furnace steelmaking (yield kg/kg);
Ratio of steel production to external scrap input (more than 1 kg ofexternal scrap is required to produce 1 kg of steel)S

Application rate of external steel scrap used in iron- and steelmaking
process (kg/kg); The equation does not target process scrap and steel
shop scrap

Table 3 Example of Trial Calculation of LCIEoL
X
Steelworks I(Blast furnace method image)

1.97

Steelworks II(Electric arc furnace method image)

0.66

RR

Xpr

Xre

Y

0.88

2.04

0.47

0.93

S

LCIEoL

0.05

0.76

0.95

0.76

Fig. 4 System Boundary for LCI Calculation of Steel Products with EoL Recycling

An entire amount of steel
scrap (recovered usedsteel products) is effectively reused as the material in iron and steelmaking
process.

In the recycling process,steel products are easily
recovered by use of magnetic force as the scrap,
which is used again as thematerial in electric arc furnace steelmaking.

we are promoting the calculation of LCI values for specific steel products based on production data collected by participating companies and employing this LCI calculation
approach. The specific LCI values calculated for each product are targeted for public release in March 2016.
We will be glad if this article proves helpful in promoting an understanding of theunique, high recyclability of steel products
and of LCI calculations that fully incorporate
this high recyclability.
￭
References
1) worldsteel (2011): Life cycle assessment
methodology/report methodology report
Life cycle inventory study for steel products/Appendix 10: Recycling methodology.
Steel Construction Info.: http://www.steelconstruction.info/Recycling_and_reuse

Nearly an entire amountof steel products appliedin respective purposes arerecovered as the scrap,
which is then used tomake renewed steel products.

December 2015 Steel Construction Today & Tomorrow 8

Steel StockMaterial Stock and the End-of-life
Recycling Rate of Steel
Ichiro Daigo: Associate Professor at Departmentof Materials Engineering, Graduate School of Engineering, The University of Tokyo. 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.

by Ph.D. Ichiro Daigo
Department of Materials Engineering,
Graduate School of Engineering, The
University of Tokyo
Steel Stock Accounting
Currently, more than 1,500 million tons ofcrude steel are annually produced worldwide
for use in such diverse fields as bridges, steel
towers, buildings, automobiles and machin-ery. In the 1850s, the invention of the Bessemer steelmaking process enabled the lowcost mass production of crude steel. Over theensuing 160 years, products manufactured
from crude steel have been accumulating

Photo 1 In-use stock of steel

Fig. 1 Steel Stock in Japan during 1980 to 2000
Obsolete stock

Stock (million tons)

Infrastructural stockIn-use stock(Year end)
9 Steel Construction Today & Tomorrow December 2015

within the inventory of manmade products
and now form a mass of material stock. Because it is easily recycled, this steel stock offers great potential as a secondary, post-service-life source of steel.
In the beginning of this article, I will simply discuss the concept of material stock consisting of steel products. Steel products havebeen accumulating within technoshpere as
structural members used in the diverse fields
mentioned above. These products continue toserve as end-use steel products until their respective service lives expire. While still serviceable, such items are called in-use stock(Photo 1).
If we ask whether or not there are anyother categories of steel stock, the academic field of industrial ecology proposes two
additional categories: obsolete stock and hibernating stock. Obsolete stock is denoted as
stock that has reached its specified service
life and fallen out of service, but still exists.
Hibernating stock denotes a subset of obsolete stock that has the potential for future recycling, like an animal that awakes from hibernation in the spring.
Fig. 1 shows the transition of accumulated
steel stock in Japan. While the infrastructural stock shown in the figure cannot be foundin the materials other than steel, it is considered to consist almost exclusively of steel
products, and it denotes existing steel stockthat is applied in infrastructure having a nearly semi-permanent service period (Photo 2).
Material Flow and Stock Analysis
Roughly two methods are used to estimate
steel stock: one is the bottom-up method
which counts all existing steel products, andthe other is the top-down method which calculates the difference between the input anddiscarded amounts (called the net addition to
stock). The steel stock in Fig. 1 is counted using the top-down method.
The difficulty in this calculation is how todetermine the discarded amount. In order toestimate the entire volume of steel stock, in-Fig. 2 Material Flows of Steel after Discarding as End-of-life Products
Import ofscrap

Hibernatingstock

Recoveredsteel scrap

In-use stocks

Domestic disusedmaterials

Export ofused products
or parts

Steel scrap
generation
potentials

Domesticallyrecycled
obsoletescrap

Remaining(Landﬁll
Obsoletestock

Loss during recycling
processes, e.g., mixing
into other material cycles(dissipative ﬂow))

Export ofsteel scrap
Hibernating stock
Obsolete stock

Fig. 3 Lifetime of End-use Products with a Range of Uncertainty

Photo 3 Crush barriers on a disused road as acase of hibernating stock(Regarding buildings and automobiles, actual lifetimes for them can be obtained by statistics.)

Lifetime of products (years)

Photo 2 Slit dam as a case of infrastructural stockcluding both in-use and obsolete stocks, theamount of recovered steel scrap is used as thediscarded amount. On the other hand, in order to estimate the in-use stock, it is necessary to count the amount of steel products
contained in all end-use products that haveexceeded their service life and have been discarded, which can be called as the steel scrap
generation potential. The flow amount shownat the right in Fig. 2 is the discarded amounts
for the entire stock and the flow amountshown at left in Fig. 2 is for the in-use stock.
While it is difficult to conduct a practical measurement of in-use stock, in-use stock
can be estimated by means of dynamic analysis. In the dynamic analysis, the steel scrap
generation potential in each year is estimatedemploying the distribution of the lifetime ofrespective end-use products (Fig. 3) and thesteel input to respective end uses in each year
in the past.
Fig. 2 shows the flow of steel products
discarded after end of service life (or recovered steel scrap). In addition to the export
and import of scrap and used products, loss
also occurs within the flow of the recycling
process; and, some steel products are subjected to reclamation. Among steel productsthat remain unrecovered are steel piles used
for building foundations that are left in the
ground after site demolition, as well as crush
barriers installed in front of closed tunnels
that have been taken out of service (Photo 3).
Scrap Recovery That Exceeds the
Scrap Generation Potential
RR (end-of-life recycling rate) is a variable in
the LCI (life cycle inventory) methodologythat relates to the recycling effect. Because
December 2015 Steel Construction Today & Tomorrow 10

High-performance Recoverability of
Steel
In the current study, we have obtained muchnew information. The end-of-life recycling
rate of steel products in Japan has been highover the past 20 years or so-more than 80%(see Fig. 5). Further, it is known that the recovery rate greatly fluctuated from about
80% to about 110% depending on the scrap
price and the steel product demand in any
11 Steel Construction Today & Tomorrow December 2015

Fig. 4 Comparison between the Steel Scrap Generation Potentials and the Recovered Steel Scrap
  (in the cases of the most likely value (a), the maximum value (b), andFig. 4 Comparison
betweenthe (c))Steel Scrap Generation Potentials and the Recovered Steel Scrap
the minimum
value(in the cases of the most likely value (a), the maximum value (b), and the minimum value (c))

Steel scrap (million tons)(a) Most likely value

Steel scrap (million tons)(b) Maximum value(C) Minimum value

Steel scrap (million tons)

various definitions are applied pertaining torecycling rates, the end-of-life recycling rate
is a term used to distinguish it from otherdefinitions. The end-of-life recycling rate ofsteel stock is defined as a ratio with the steel
scrap generation potential set as the denominator and the recovered steel scrap as the numerator. The values of the denominator andnumerator are as described above.
Fig. 4 (a) compares the estimated value ofthe steel scrap generation potential and theestimated amount of recovered steel scrap
in Japan from 1987 to 2010. It is understoodfrom the figure that in each of the two years
from 2007 to 2008, the steel scrap was recovered from end-of-life products that had already exceeded its service life before 2007at levels higher than the scrap generation potential. However, inherent in estimating the
scrap generation potential was a range of uncertainty for the lifetime attributed to end-use
products as shown in Fig. 3. The resulting
maximum and minimum values for these twoparameters are shown respectively in Fig. 4(b) and Fig. 4 (c). Even when this uncertainty is taken into account, it can be concluded that the steel scrap recovered in both 2007
and 2008 exceeded the scrap generation potential for those years.
During the 2007 to 2008 period, both theprice of resources and the demand for steel
products were high, and thus the high recovery rate is believed to attributable to that,while certain steel products had finished theirservice life in the past several years, theseproducts left behind were intensively recovered as the scrap in that period.
The following are accepted as factors forthe intensive recovery efforts of 2007 and2008. When steel waste products were generated in suburbs where the recovery costs
were high, they were often left behind if they
did not pose a legal or safety issue and if the
profit from their sale as scrap did not offer
sufficient economic incentive for recovery.
However, because the price of steel scrap
in 2007-2008 was high, end-of-life productsthat had been left behind in this way as hibernating stock were recovered, which led to thehigh recovery rates of 2007 and 2008.

Fig.
5 End-of-life Recycling Rate of Steel in Japan
Fig. 5 End-of-life Recycling Rate of Steel in Japan

End-of-life reccyling rate

(The
upper
and
lower
boundsa ofrangeof uncertainty.)(The upper
and
lower
boundsshowshowa rangeuncertainty.)

Upper boundLower boundSteel scrap [million tons]

Fig.6 6
Amountof Heavy
Scrap by
Recoveredby Category
Fig.
Amountof Heavy
Scrap Recovered
Category relative
to its EoL-RRrelative to its EoL-RR

given year. From these sizeable fluctuations,
it can be said that the RR, one of the variablesin the LCI methodology that pertains to therecycling effect, should not be assessed using
the data in a single year; rather, it would be
more appropriate to apply an average of theannual values over a longer term. As shownin Fig. 6, it was learned that the steel scrap
whose recovery was most dependent on priceand/or demand was heavy scrap, particularly
low-grade heavy scrap.
In the period when scrap prices were soaring, two specific features were noted: one,even hibernating steel stock is recoverable
and, two, the amount of hibernating steel
stock thus recovered cannot be disregarded interms of total recovery (refer to Fig. 7). From
the above, just because certain amounts ofsteel stock are not recovered once does notmean that they cannot be recovered later.
Therefore, it can be said that as long as steel
stock remains within the inventory of manmade products, it has the potential to serve asa future secondary resource.
Among the major reasons for the high recyclability of steel products are: ease of separation from other materials by means ofmagnetism, the possibility of removing impurities in the steelmaking process without
using electrolysis and the high allowable levels of impurities. In addition, steel products
dominate in terms of their high recoverability, including recovery-time buffer from theend-of-life product.
￭

Fig. 7of theRoleRoleof Hibernating
StockStockin Recovery
Mechanisms
Fig.
7 Schematic
SchematicIllustration
Illustrationof theof Hibernating
in Recovery
Mechanisms

Pool of hibernating materials (hibernating stock)In-use stock

Recoveredscrap

December 2015 Steel Construction Today & Tomorrow 12

Eco-friendly Steel Production Processes and Products

Steel Construction Products Conduciveto Supporting an Eco-friendly Society
by Shinji Kitano
Chairman, Committee on Environment-friendly Steel for Construction, The Japan Iron and SteelFederation

Blast Furnace and Electric Arc Furnace
Methods in Iron- and Steelmaking
Steel products use two kinds of steel: basic oxygen furnace steel that is produced at an integrated steelworks where pig iron is produced in ablast furnace using iron ore and coal as the main
raw materials; and electric arc furnace steel thatis produced in an electric arc furnace using steel
scrap as the main material.
In the basic oxygen furnace process, the pig
iron (molten iron) that is produced in a blast
furnace by reducing and melting iron ore using coal is then refined in a basic oxygen furnace to produce high-grade steel. Meanwhile, inthe electric arc furnace process, steel scrap thatis purchased from the domestic market is arcmelted and refined in an electric arc furnace toproduce specialty steel and ordinary steel.
The steel industry supplies diverse kinds ofsteel products to society by best matching theprocess characteristics of the blast furnace andelectric arc furnace methods and according to
the location of the steel plants and the types of
products to be made (Fig. 1).
With the ongoing economic development
13 Steel Construction Today & Tomorrow December 2015that is occurring in emerging nations such as
China and India, world steel demand is trending upwards in both medium-term and longterm forecasts. Leading up to the 1990s, world
crude steel production was in a transition periodthat averaged about 700 million tons/year, but,entering the 21st century, the scale of production has rapidly risen in the emerging nations,particularly in China, with the result that world
crude steel production surpassed the 1,600 million ton-level in 2014.
In such a situation of growing crude steel
production, it is noted that the rate of increasein the production of basic oxygen furnace steel
considerably exceeds that of electric arc fur-nace steel (Fig. 2). This is because steel scrapthat serves as the raw material for electric arc
furnaces is not fully generated unless a certain level of social infrastructure is accumulated. While the international distribution of steel
scrap flows from the advanced nations to thedeveloping nations, the amount of scrap that is
generated cannot meet all the demand found in
the developing nations. Accordingly, because it
is impossible to rely solely on electric arc furnaces to meet the currently increasing world demand for crude steel, it is essential to depend on
the integrated blast furnace-basic oxygen furnace process to produce and supply the needed crude steel.

Fig. 1 Iron- and Steelmaking Process

Fig. 2 Crude Steel Production in the World
1800
1600

Crude steel production (million tons)

Steel: High in Performance, Economy
and Recyclability
Steel is the metal that people know best, andmore than 90% of all metallic end products are
manufactured using steel. An uncountable number of products made from steel are used in ourdaily lives. Iron accounts for about 30% of the
Earth’s total weight and are said to be its richest resource. In addition, because iron is magnetic, it can easily be separated from other materials and easily recovered after the end of its
service life.
Although a diverse range of new materials
have debuted to create an age of materials diversity, iron in particular is a resource-rich material that not only combines the characteristics
of performance and economy but also demonstrates high recyclability.
The Japanese steel industry has developed
and marketed diverse kinds of eco-friendly
products. This article introduces the industry’s
initiative to promote global environmental preservation and the environmentally friendly steel
construction products.

Other

1400

Electric arc furnace steel

1200

Basic oxygen furnace steel

1000
800
600
400
200
0

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

In the electric arc furnace process, because
scrap is melted using electricity, it is noted that
CO2 emissions arising from the electric arc furnace process are less than those of the blast

furnace process where iron ore is reduced using coal. However, steel products produced in ablast furnace eventually become obsolete scrap,
which is then used as the main raw material in

Fig. 3 Concept of Steel Recycling

Iron ore Reduction Iron ore
capacity
Small
Large

Scrap

Scrap

Blast furnace/basic oxygen furnace process

Electric arc furnace process

Primary steel product(use mainly of iron ore)
Secondary product (use of scrap)
Circulation pool of steel product (scrap)
Source : LCA Methodology Report (worldsteel, 2011)

Fig. 4 Major Energy- and Resources-saving Technologies Applied in Steelworks
,
70s

,

1）Process innovation：
Process improvement：,

80s

Continuous casting,continuous annealing

Pulverized coal injection, coal moisture control

Hot charge rolling,
automatic combustion control Artiﬁcial intelligence, supply chain network
Gas holder, high-efﬁciency gas turbine
compound power generation

TRT, CDQ,
10s

Continued improvement
Continued improvement
Continued improvement

Regeneration burner Continued improvement

Continued improvement

Net consumption

Process innovation
Process improvement

Recovery

Total energy consumption*4）Utilization of wastes：Plastic waste,
used tire, biomass Gasiﬁcation

Ferro-coke2）Byproduct gas recovery, highly efﬁcient utilization
3）Waste heat recovery：

,
00s

90s

Byproduct gas utilization

Waste heat recovery
Waste material utilization*COURSE-55: Research project on the technology to reduce blast furnace CO2 emissions and to separate/recover CO2 from blast furnace gas

Source: Commitment to a Low-Carbon Society (The Japan Iron and Steel Federation)

Fig. 5 International Comparison of Unit Energy Consumption in the Steel Industry
Unit energy consumption in steel industry(blast furnace/basic oxygen furnace process)Index set at 100 for Japan

Japan

Korea

Germany

France

U.K.

India

BrazilU.S.A.

Source: Indexing of data in “Estimate for Unit Energy in 2010”
prepared by Research Institute of Innovative Technology for the Earth

Russiathe electric arc furnace process. In this way, it
can be understood from a long-term perspectivethat all the steel products produced, whether inthe blast furnace or electric arc furnace process,form an integrated circulation pool. All iron andsteel products are subjected to repetitive recycling via this circulation pool (Fig. 3), which
contributes to an overall savings of both energy and resources.
Even when all the iron- and steelmaking
processes operating in Japan are switched fromthe blast furnace method to the electric arc furnace method, this switchover will not lead toa reduction of the Earth’s total CO2 emissions.
This is because, in order to balance the resulting decrease in scrap exported from Japan, there
will have to be a corresponding increase in thesteel produced in other nations using the blast
furnace process. In other words, so-called carbon leakage is brought about by increased production that relies on the low-energy efficiency
blast furnaces used in other nations, which will
naturally lead to an increase in total worldwide
CO2 emissions.
Steel Industry Initiatives for the Prevention of Global Warming• Prevention of Global Warming in Ironand Steelmaking Processes
The Japanese steel industry has actively promoted environmentally friendly iron- and steelmaking operations and continues to do so. Amongthe comprehensive environmental countermeasures being promoted are the world’s most advanced energy efficient production methods,
the effective utilization of steelworks byproducts, the preservation of atmospheric and water
quality and the forestation of steelworks compounds.
Particular note should be taken of the effective utilization of energy. A great amountof the energy generated as a byproduct of every process at a steelworks is recovered and reused. Byproduct gases generated by coke ovens, blast furnaces and basic oxygen furnaces
are recovered and serve as energy sources forother equipment.
Further, other types of energy are also recovered for reuse. For example, the top pressure
used in the top-pressure operation of a blast furnace is recovered by means of the top-pressure
recovery turbine (TRT) to generate electricity,and the waste heat generated by coke ovens is
also recovered by means of coke dry quenchingequipment (CDQ). Fig. 4 shows the major energy-saving technologies that have been introduced in steelworks operations in Japan. As aresult of sustained efforts made to improve operations, the Japanese steel industry is now theworld’s most advanced in energy efficiency, as
shown in Fig. 5.
December 2015 Steel Construction Today & Tomorrow 14

The Japanese steel industry intends not only to continue its efforts to further mitigate global warming but also to disseminate throughout
the world the knowledge that it has gained fromthese initiatives and experience and to positively promote international cooperation in thisfield.
• Effects of CO2 Emissions Reduction at
the Steel Product Application Stage
Steel products are widely used for diverse application purposes to produce diverse kinds of end
products. Most of these end products are used in
the efficient mass transport of people and cargo
and operate with high energy efficiency, which

in turn contributes towards a reduction of greenhouse gas emissions.
The CO2 emissions suppressed by the use ofend products manufactured using the high-performance steel products developed by the Japanese steel industry are estimated to have been
9.76 million tons in Japan in FY2013, and thesame end products exported overseas resulted
in the suppression of 15.82 million tons (Fig. 6).
One of the steel products that enable the highest energy efficiency for end products is highstrength steel sheet for automobiles. The lightweight automobiles brought about by the use ofhigh-strength steel sheet contribute towards improved fuel efficiency. Similarly, high-strength

Fig. 6 Effects of CO2 Emissions Reduction Attainedin Five Major End Products (Estimates for 2013)
Domestic use

ExportTransformer

Transformer

Reduction of
CO2emissions
9.76 million tons

Ship

Ship

Reduction of
CO2 emissions
15.82 million tons

Train
Automobile

Power generation
boilerAutomobile

Power generation
boilerCO 2 emissions reduction: 25.50 million tons (target steel products: 7.52 million tons)
Source: The Institute of Energy Economics, Japan*Five steel products of automotive steel sheet, oriented electrical steel sheet, shipbuilding steel plate, boiler tube and stainless steel plate;
3.677 million tons in domestic use and 3.845 million tons for export in FY2013, totaling to 7.522 million tons
*Start of assessment for CO 2 emissions reduction: Domestic use from FY1990, export (automobile sheet and shipbuilding plate) from FY2003,
boiler tube from FY1998, and electrical sheet from FY1996

Fig. 7 Case of Demolition and Reuse of Steel Structure (Tonegawa Bridge on Joban Line)The eight-span Tonegawa Bridge on the Joban Line in Ibaragi Prefecture, constructed in 1916,
was dismantled to three sections, each of which is currently reused as the railway bridge in threelocations: Aganogawa Bridge spanning Agano River in Niigata Prefecture, Shogawa bridge
spanning Sho River in Toyama Prefecture, and Daini-Takahara Bridge spanning Daini-Takahara
River in Gifu Prefecture.
Aftertransfer

B：Shogawa BridgeAftertransfer

A：Aganogawa BridgeAftertransfer

C：Daini-Takahara Bridge

15 Steel Construction Today & Tomorrow December 2015

Dismantling Tonegawa Bridge
on Joban Line
into A, B, and C

steel plate for shipbuilding also contributes towards improved fuel efficiency. The oriented electrical steel sheets used for transformers eliminate electricity loss, and heat-resistanthigh-strength steel tubes contribute to improved
power generation efficiency.
Steel Construction Products Conducive
to Preserving the Global Environment• Steel Construction Products Conducive to Lessening Environmental Impacts
In addition to reducing steel usage, steel construction products with increased tensile
strength help to reduce global environmental
impacts in other ways, such as decreasing construction waste, preserving resources and prolonging the service life of structures and equipment. Specific examples are:-Reduction of construction waste
Because steel products are recyclable, they produce almost no waste. This advantage not only reduces the cost of waste treatment but also
helps to prolong the service life of final wastes
disposal site whose securement is threatening.
-Resources savings
Steel is said to be the ultimate eco-friendly material insofar as products made with steel canbe easily disassembled, reassembled and repetitively reused. As an example, there is the caseof a certain railway bridge that, after being usedat one site, was dismantled, moved and reusedat three other sites (Fig. 7).
-Prolonged service life of building
structures
Steel-frame structures allow large-span construction and have no need of seismic-resistantwalls; thus, they are suitable for enlargement
and rebuilding. Further, steel-frame structures
allow construction of long-serviceable buildings that can flexibly meet future change ofbuilding application purposes.
• Steel Construction Products in Harmony with Nature
Capitalizing on the strength, workability andother excellent properties of steel, diverse typesof steel construction products have been developed that harmonize with nature. In construction projects that are promoted close to nature,
it is important to harmonize with and preserve
the natural environment. In this regard, the steel
construction products that have been developed
thus far have had little damaging impact onoriginal nature and play an inconspicuous but
vital role in preserving nature in diverse ways.
Further, after the long service life of these products is complete, they are effectively recycled.
Specific examples are:-Water-permeable steel pilings
The application of steel pilings with water-permeable holes allows for the constructionof steel pile walls that do not impede existingwater flow and give adverse effects on the local ecology and natural environment. The results of analysis show that: in cases when the
openings account for 0.4% of the total pile surface area (or 1,000 openings with diameters of
55~70 mm), 80% of the original flow can be
maintained. (Fig. 8)-Steel pile embankments using planting fins
Planting fins hold the soil that serves as a foundation for raising perennial plants. The attachment of these fins to steel pile revetments allows for the greening of embankments in amanner that conceals the steel pile surface without impeding the function of the revetments.
(Fig. 9)-Water-permeable steel dams to prevent sand buildup
Water-permeable steel dams (slit dams) catchboulders and driftwood that are generated during debris flow and large floods. They also allow subsequent mud flows to pass downstream.
Further, during normal periods, these dams
have no effect on the flow of mountain streams
and they permit water and sand to pass freely,
thereby allowing the free movement of fish andplant lives. To this end, water-permeable steel
dams are able to mitigate violent acts of nature while at the same time leaving nature undisturbed. During normal periods, these dams
block the flow of neither earth nor sand, andprevent the drop of the level of riverbeds andthe retreat of coastlines so that the ecosystem
can be preserved. (Fig. 10)-Water-impermeable steel dams toblock sand
The application of sand and stones obtainednear these dam sites as filling materials for thedam barricade (70% or more in Eco-mark certification standard) allows for the constructionof dams that do not adversely effect the ecosystem. Further, these dams greatly reduce the volume of waste materials (such as residual sand)that must be removed, which mitigates their environmental impact. (Fig. 11)
Steel Industry Efforts to Tackle Global
Environmental Concerns
Measures to treat global environmental concerns will become increasingly important forevery industry in the future. To meet this situation, the Japanese steel industry will continue topromote not only further energy- and resources-savings in its production processes but also the development of higher-performance andeco-friendly steel products—with a final goal ofcontributing to the prevention of global warming and the formation of a recycling-oriented
society.
￭Fig. 8 Water-permeable Steel PilingFig. 9 Steel Pile Embankment Using Planting Fin

Fig. 10 Water-permeable Steel Dam to Prevent Sand Buildup

Fig. 11 Impermeable Steel Dam to Block Sand

December 2015 Steel Construction Today & Tomorrow 16

A List of Steel Construction Technologies

Steel Construction Technologies inJapan
In 2014, at the request of the Ministry of Land,
Infrastructure, Transport and Tourism, the Japan Iron and Steel Federation (JISF) compiled
a list of steel construction technologies in Japan (in English). The list concisely introduces
a total of 27 different types of steel construc-tion technologies and steel materials for use
in the fields of building construction and civilengineering so that these technologies and materials might be more readily known and available for use in overseas applications.
The full contents are available on the JISF

High-strength Steel for Buildings (SA440, H-SA 700)
SA440 (tensile strength: 590 N/mm2-grade steel) and H-SA700(tensile strength: 780 N/mm2-grade steel) are high-strength steels
developed for building construction. Use of these high-strength
steels permits downsizing and weight reduction, especially for
Dimension ofConventional
SN490B

website: go to (http://www.jisf.or.jp/en/activity/sctt/index.html) for free public access.
Introduced below are four typical items
excerpted from the list.

large-size and extra-heavy sections of steel frames, e.g. steel
framing columns for high-rise buildings. These steel materials
are also effective in reducing the weight of roof trusses and other heavy members.
Reduction of Steel Weight Attained
by Use of High-strength SA440 and H-SA700

Reduced Sectional Dimension of SA440 and
H-SA700 due to Higher Strength

Weight/equivalent strength

100%
80%

66%

60%

42%

40%
20%
0%

Fire-resistant Steel
Fire-resistant steel exhibits higher strength at high temperatures
than do conventional steel building materials. It is guaranteed thatat 600°C the proof stress of this material is at least two-thirds theproof stress specified at room temperature. Fire-resistant steel al-100%

SN490B

SA440Blows the reduced use or elimination of fire protection in the construction of multistory parking facilities and other buildings. Thismeans that such advantages as lower cost, a shorter construction
period, and a better working environment can be expected.

High-temperature Performance of Fire-resistant Steelat Elevated Temperatures
Yield strength (N/mm 2)
400

YP
Fire-resistant steel

300

217 (N/mm 2)

200

YP
General steel (SN490)

100

YP：Yield point

0

20

100

200

300

400

500

Temperature (°C)

600

17 Steel Construction Today & Tomorrow December 2015

700

800

H-SA700

Example of application of ﬁre-resistant steel in multi-story car park

Steel Slit Dams for Controlling Debris Flow
This is a permeable steel slit dam built by joining together steel tubes that have outstanding
shock absorption. This structure shows particular concern for the environment, as it is designed not to disturb normal river flow, thus
allowing the unimpeded passage of water andinoffensive earth and sand. However, once a
debris flow occurs, any offensive matter is certain to be captured.

Control of Debris Flow by Steel Slit Dam
Normal condition：

Water and harmlesssediments ﬂow down
under normal conditions.

In case of debris ﬂood：

Shift-type structures is designed considering the ecosystem, which does not disrupt river ﬂow.

Weathering Steel for Bridges
Weathering steel forms protective rust on every surface due to theaddition of such elements as Cu, Ni, and Cr. This protective coating of rust is tight and homogeneous, and is characterized by anextremely slow rate of corrosion. This property allows weathering steel to serve a long time without surface painting. This leads
to reduced maintenance costs for steel bridges.

Image of Lifecycle Cost Reduction in Weathering Steel Bridges

Cost for corrosion protection

Weathering steel (without painting)
Weathering steel (surface-treated)
Painted steel (C5 paint)Years after construction
Application of weathering steel bridge in remote mountainous area

December 2015 Steel Construction Today & Tomorrow 18

JISF Operations

Two Seminars Held in Thailand were dispatched as lecturers from Japan. Both seminars were a
Byproduct Recycling,” to which two specialists in these fields

The Japan Iron and Steel Federation (JISF), in collaboration with
the Iron and Steel Institute of Thailand (ISIT), held two seminars
in October 2015 in Bangkok. These two seminars were planned aspart of government-initiated cooperative projects pursuant to theJapan-Thailand Economic Partnership Agreement.
One was a seminar on steel bridges held October 13 and 14.
Four bridge experts, including two dispatched from Japan, gave
two lectures titled “Introduction of Steel Bridge and its Advantages” and “The Outline of Suspension Bridge.” The other event
held on October 15 was a seminar titled “Waste Management andsuccess with many participants.
Among other similar cooperative projects in the planningstage are JISF sponsorship in Japan of “Steel Construction Seminar in Japan” and “Newly Recruited and Junior Engineers Training Course in Japan.”
Seminar on the environment and energy conservation

Seminar on steel bridges

Mr. Nattapon
Mr. Nuttapon
Ratanamalee (ISIT) Suttitam (ISIT)

Mr. Toru Watabiki(JFE Engineering
Corporation)

Mr. Hiroyuki Okada(Nippon Steel &Sumitomo Metal
Corporation)

Survey Results for Steel
Construction Today & Tomorrow

From August 2014 through June 2015 our overseas readers of theperiodical Steel Construction Today & Tomorrow (English-version)
were asked to participate in surveys, as reported in Issues 42 to 44.
We wish first to express our great appreciation for our readers’ kindness in participating in the current survey. Thanks to yourgenerous cooperation, many useful results were obtained, some ofwhich are introduced below.
Survey respondents numbered 58, with those from Southeast
Asia leading the way. Specifically, 97% of the participants said that
this periodical is beneficial in their current job; and 88% had experience utilizing steel structures in their current or past jobs. It became
obvious that structural steel shapes were the most widely used of all
steel-structure materials, mainly in Southeast Asian nations.
Meanwhile, the primary reason why steel structures were notchosen was their high cost, with the runner-up being the intent of
the clients. With regards to themes that readers would like to seetaken up in the future, bridges come first, followed by construction,
expressways, corrosion protection, earthquake resistance, and railways in that order.
It will be our firm policy to reflect seriously on these survey results when considering future editing plans.

STEEL CONSTRUCTION TODAY & TOMORROW
Published jointly by

The Japan Iron and Steel Federation
3-2-10, Nihonbashi Kayabacho, Chuo-ku, Tokyo 103-0025, Japan
Phone: 81-3-3669-4815 Fax: 81-3-3667-0245
URL http://www.jisf.or.jp/en/index.html
Japanese Society of Steel Construction
Yotsuya Mitsubishi Bldg. 9th Fl., 3-2-1 Yotsuya, Shinjuku-ku, Tokyo 160-0004, Japan
Phone: 81-3-5919-1535 Fax: 81-3-5919-1536
URL http://www.jssc.or.jp/english/index.html(from left to right) JISF staff, Mr. Noriji Numata (JFE
Steel Corporation), Mr. Songwoot Graiparpong (ISIT),
Mr. Teruo Furuyama (Nippon Steel & Sumitomo Metal
Corporation)

Usefulness of Steel Construction Today &Tomorrow for your current work (%)
Not so helpful Not helpful
3.4
0.0

Comparatively
helpful34.5

Very
helpful62.1

Is the steel structure used in your current work? (%)
Not used
until now
12.1

Unknown
3.4
Used in thecurrent work
65.5

Used in thepast work
22.4© 2015 The Japan Iron and Steel Federation
Edited byCommittee on Overseas Market Promotion, The Japan Iron and Steel Federation
Chairman (Editor): Kaoru Uehara
P u b l i s h e d t h r e e t i m e s p e r y e a r, S T E E L C O N S T R U C T I O N TO D AY &TOMORROW is circulated to interested persons, companies and publicorganizations to promote a better understanding of steel products and theirapplication in the construction industry. Any part of this publication may be
reproduced with our permission. To download content (PDF format), please go
our website at: http://www.jisf.or.jp/en/activitity/sctt/index.html. We welcome yourcomments about the publication and ask that you contact us at: sunpou@jisf.or.jp.