No. 70 April 2024

STEEL CONSTRUCTIONTODAY & TOMORROW

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

Special Issue

Japanese Society of
Steel Construction
JSSC Commendations for Outstanding Achievements in 2023

• Outstanding Achievement Awards

1 OSAKA UMEDA TWIN TOWERS
SOUTH

2 Ariake Arena-Seismically-isolated Large-space
Roof Structure-

3 Centennial Main Building of
SIT Toyosu Campus

4 TOKYO TORCH Tokiwabashi
Tower• Technical Paper Awards

5 Effects of Beam Cross-Sectional Size and Web Connection Typeon Mechanical Properties of Beam-to-Column Connection

6 Experimental Study on the Influence of Thin Mortar Layer andHeaded Stud Spacing of the Precast Concrete Slab on
Composite Girder Bridges

Special Topic: Steel Construction Projects Overseas

7 “Tao Zhu Yin Yuan” High-rise Residential Building in Taipei
10 Construction of Elevated Bridges in the Urban Area of Sri Lanka
Special Article: Stainless Steel

13 Large Stainless Steel Roof at Japan National Stadium
JSSC International Events

15 2023 China-Japan-Korea Tall Building Forum in Tokyo, Japan17 13th Pacific Structural Steel Conference (PSSC2022)
Message from JSSC Executives

19 President of the Japanese Society of Steel

Construction and Chairman of the International Committee

Published Jointly by

The Japan Iron and Steel Federation
Japanese Society of Steel ConstructionJSSC Commendations for Outstanding Achievement in 2023-Outstanding

OSAKA UMEDA TWIN TOWERS SOUTH

Prize winners: NIHON SEKKEI, INC. and Takenaka Corporation
Building Outline
OSAKA UMEDA TWIN TOWERS SOUTH
is a high-rise composite facility composedof a department store and offices (Photo 1).
The low-rise base platform section is for department store use, where a continuous Lshaped plane is adopted that matches thesite configuration. The high-rise section isfor office use, where a rectangular plane isadopted that is suitable for the office layout.
An outstanding feature of this building is its unique configuration in which thehigh-rise section with a height of 189 m isstacked on the base platform section with an
L-shaped plane measuring 150 m × 150 m.

In order to suppress the damage occurring during an earthquake, a response-control structure is adopted. Two kinds of response-control devices are adopted-a
hysteretic damper that applies the bucklingrestraint brace manufactured by employing low yield-point steel (LY225) as a coreplate and a viscous damper that applies theoil damper and viscous wall damper.
Damping Tail Response Control
At the department store located on the Lshaped base platform section, it was required to intensively arrange the brace andresponse-control frame to the one sidedisposed backyard. For the north side of
the building where the high-rise floors arestacked, a high-stiffness hysteretic damper (buckling-restraint damper) was adopted, and for the south-east side of theStructural Outline
The main structure adopted for the aboveground floors is a steel structure, and that for
the underground basement level is a steel
structure and an SRC structure (Fig. 1).

building where the medium-rise section
is located, a flexible rigid-frame structure was adopted. In order to suppress torsion occurring during an earthquake, thecenters of both stiffness and gravity wereplaced close by devising a balanced frame
stiffness in conformity with the weight of
the respective structures. (Refer to Fig. 2)
In addition, the oil damper and other response-control devices were arranged intensively at the south-east end (tail) of thebuilding, which is most distant from thecenter of stiffness, to develop a new response-control framing or damping tail response control that efficiently absorbs seismic energy (Fig. 3). Also, for the connecting
section of the L-shaped plane, two parallelly-arranged/large-section steel box beams
called a rail beam were installed to improve
the strength of the connecting section.

Fig. 1 Structural Outline

189 m

High-rise floors
are stacked

Hat truss
Large-capacity
6,000-kN
oil damper

Frame above the roadN

Rail beam
Viscous wall
damper, etc.
L-shaped baseplatform section

Belt truss
High-risesectionBase
platform
sectionBase
platform
sectionBucklingrestraint
brace
Road

Ab

Road

out

Photo 1 Full view of the building

Fig. 2 Center of Stiffness and Center of Gravity at L-shaped Plane

150

t
ou

m

Ab

0m

15

Fig. 3 Damping Tail Response Control

CounterG
R
Buckling-restraint brace(Hysteretic damper)

Body

Stiff

Rail beam

Backyard

Damping tail response control

Tail

Backyard

Oil damper, etc.

Oil damper, etc. (Viscous damper)
1 Steel Construction Today & Tomorrow April 2024

Flexible

Rail beamAchievement Awards

Ariake Arena-Seismically-isolated Large-space Roof StructurePrize winners: Kume Sekkei Co., Ltd. and Takenaka Corporation
Outline of Building Plan
Ariake Arena is a building that is assumed to be used not only for sports but
also as a venue for concerts and otherevents. Its specific features in design andconstruction are as follows:• The elevation configuration that characterizes the appearance opens upward andthe ceiling has a convex shape downward.
• The large-span roof framing is seismically base-isolated.
• The traveling method was adopted as
the roof construction method.
Table 1 Building Outline
Name

Ariake Arena

Project
ownerTokyo Metropolitan
Government

Location

Ariake, Koto-ku, Tokyo

Construction
terms

April 2017~December 2019

No. of floors

5 floors abovegroundTotal floor area

47,252.98 m2

Structure

Seismic-isolated structure(seismic-isolated roof)

DesignKume Sekkei Co., Ltd.
(basic design)

These features were devised as an important means of realizing the following
three requirements-the minimization of
the air volume while securing the spectator capacity under restricted site conditions, a structural plan that suppresses the response acceleration of the roof
in order to mitigate the danger of fallingceiling and suspended equipment during
great earthquakes, and the constructionof the building in a shorter term.
Outline of Structural Plan
The building is composed of four main
structures-roof structure composed of
the truss with a span of more than 120
m, upper structure composed of the standstructure with seats and core framing
structure arranged in the four corners,
seismic-isolation layer arranged between

roof structure and upper structure, andfoundation structure that supports the upper structure.
In the erection of the roof structure, a
traveling method was adopted in which
each truss was assembled one by one ona temporary platform to be installed on
the sub-arena and the trusses thus assembled were sent out in an orthogonal direction to the truss. In order to secure theself-standing stability of the roof underconstruction, the roof truss was designed
as a one-way truss for dealing with longterm loading.
In the column section that supports
the roof, the ribbed wall was arranged
to secure the stiffness itself, and the roof
supporting points were adjusted in orderto cause no bending moments at the column bottom in the long-term loading.

Photo: Tokyo Metropolitan Government

Takenaka Corporation(detailed design)
Technical
guidance

Masao Saito(professor emeritus,
Nihon University)
Photo 1 Appearance of Ariake Arena

Fig. 1 Structural Diagram
Main arena roof

Main arena

About 120 m

About 130 m
Roof weight
Roof truss

V-shaped brace
LRB
Oil damper
CLB

Space between
bearings: About 110 m

Stand structure

SSR bearing

SSR
Ribbed wallRC
projecting
columnRibbed wall
RC projecting column
Sub-arena

About 179 m

Core framing structure

Buckling-restrained brace
N
E
W

RB

S

42 m
About 138 m
Stand section
April 2024 Steel Construction Today & Tomorrow 2

-Outstanding Achievement Awards

Centennial Main Building of SIT Toyosu Campus

Prize winners: Nikken Sekkei Ltd. and Kajima Corporation

Structural Plan
For the construction of this building, acomplex structural plan was adopted inwhich the plane configuration of the upper floors is set back to an eccentric position relative to the standard floor. Becauseof this, the structural plan was worked out
so as to reduce any torsional deformation
occurring during an earthquake by not only increasing the beam depth of the girders
at the side where the weight is biased overthat of the framing of the standard section but also by intensively arranging thebuckling-restraint brace and seismic-resistant columns. (Refer to Figs. 1, 2 and 3)
In addition, because the surface subsoilof the planned site was weak, high seismic resistance was secured by adopting a
response-control structure in which threekinds of response-control members (buckling-restraint brace, oil damper and viscoelastic damper) were properly arranged.

Application of the Building as a
Teaching Material
This building was planned as a facility to be
used mainly by the students of the SIT Schoolof Architecture. Therefore, the response-control member and its supporting framing
member were installed in a position wherestudents can see and touch them on a daily
basis, and thus these members were intended to serve as a full-scale teaching material.
This building has provided students withthe opportunity to experience first-hand
how the building is actually constructed byseparately holding site tours by construction process and to steel-frame inspections.
The building has also provided them with aplace for learning with practical experienceby preparing a site where students practically experience the arrangement of reinforcing bars and concrete forms.
▽Maximum height: GL＋67.50

Fig. 1 Sectional Structure
CFT
Steel
column column

Building Plan
Centennial Main Building is located at thecorner of the Toyosu Campus of the Shibaura Institute of Technology (SIT) and has athree-story atrium and a pilotis space with
an approximate height of 10 m. The aim ofits building plan was to guide students tothe courtyard and the central square as a
campus gateway and to connect the campus with the town by offering a throughpass from the intersection in front of thecampus to the atrium and pilotis space.
At the same time, the plan called fora building configuration in which the façade facing the road expands diagonally
upward to not only express “development
and growth” but also create a public spaceat the base of the building. (See Photo 1)

Photo: TOREAL/Koji Fujii

Upper floor

Medium floor

Inclined column
Weld built-up box section column⃞ 700×700
Seismic-resistant column
Oil damper

Buckling-restraint
brace
Pilotis space
Lower floorLong column: Approx. 14 m
Steel tube: 1,000 in dia.
Steel pipe pile
(Rotation penetration method)
Pile length: 31.0~34.0

Photo 1 Full view of Centennial Main Building

Fig. 2 Structural Plan of Medium Floor:
Framing Elevation at 4th Floor

Rigid framing to deal with eccentric weight:
Span (about 22~28 m)
Beam depth H-1000
Long-span beam: H-1000
1F-4F

Lower floor:
Gymnasium

Fig. 3 Structural Plan of Lower Floor:
Framing Elevation at 2nd Floor Campus inside
1F-4F

Pilotis space

1F-6F
Viscoelastic damper(Floor vibration/
1F-6F
response control)
Oil damper(Response control)
Seismic-resistantcolumnBuckling-restraint brace(Suppression of torsional deformation)
About 75 m
3 Steel Construction Today & Tomorrow April 2024

About 60 m

1st basement level:
Gymnasium (atrium)

2F-3F

Plane rangeof upper floor

1F-6F
Oil damper(Response control)
Moving line inside/outside campus
Seismic-resistantcolumn1F-6F

Road in
Buckling-restraint brace
front of campus (Suppression of torsional deformation)

2F-3F

-Outstanding Achievement Awards

TOKYO TORCH Tokiwabashi Tower

Prize winners: Mitsubishi Jisho Design Inc. and Toda Corporation
Tokiwabashi Tower is a high-rise building planned as part of the “TOKYOTORCH” redevelopment project being promoted on the north side of Tokyo Station. It is a steel-structure officebuilding with 40 floors abovegroundand a height of 212 m. Multiple infrastructure facilities have already been
deployed on the project site, and the redevelopment project is being promoted
step by step capitalizing on these existing facilities.

facilities, an overhang frame was adopted that employs inclined columns
for the entire periphery of the building. This structural concept was applied to the aesthetical design of thelower floors. Specifically, the adoption of the overhang frame brought
about an open and spacious area on
the lower floors-“open terraces withlightweight and free bouncing volume
configuration” and “a large-scale under-eaves space,” which were madepossible by allowing the “free adjustment of the external wall position.”(See Photos 1 and 2)
The lower floors, which maintaincontinuity with the town and squareand offer rich structural variations,act as the face of Tokiwabashi Towerand contribute to the vitalization of thetown.

Structural Plan
In order to cope with a structural plan offering the task of adopting an asymmetrical overhang frame, a “lower stories concentrated vibration control system” wasadopted in which viscous dampers werearranged intensively in the lower floors.
This system put into effect the provision
Building Planof efficient damping performance to the
In order to secure a regularly-shaped
entire building structure, the suppression
floor plate on the typical floor whileof residual deformation and the plasticimaintaining the existing infrastructure
zation development of the main frame at
the lower floors that are
the most important strucFig. 1 Sectional Structure
tural element, and theHybrid mass damper (HMD)
suppression of torsional
200 t x 2 units
deformation there.
At the topmost floor,▽38F
two units of hybrid mass
Buckling-restraint
dampers (HMD) were inbrace (BRB)
stalled to improve habitability in the event ofstrong winds and at the
Typicalsame time to enhance thefloor
response reduction in the
Oil damper (OD)
event of an earthquake▽8F
and early stabilization of
Viscous wall damper
post-quake shaking. Pri(VWD)
Overhang
or to the completion, the
Lower
frame
excitation test was con▽1F floor
ducted to confirm the response-control effect ofElectric
Metropolitan
substation
HMD by means of its
expressway
Photo 1 Full view of Tokiwabashi Tower
practical measurement.
(Photo: Kawasumi-Kobayashi(Refer to Fig. 1)
Kenji Photograph Office)Photo: Kawasumi-Kobayashi Kenji Photograph Office
For the structure to
support the overhang
frame, a maximum of
three columns on the typical floors were integrated to one column, an inclined branch column was
installed to support an axial force of about 80,000
kN, and further the multistep larger-diameter pile
was adopted.

Photo 2 Lower floors at Tokiwabashi Tower
April 2024 Steel Construction Today & Tomorrow 4

JSSC Commendations for Outstanding Achievements in 2023-Technical Paper

Effects of Beam Cross-Sectional Size and Web
Connection Type on Mechanical Properties of
Beam-to-Column Connection

Prize winners: Koichiro Miyake and Kouhei Takatsuka
umns by high-strength bolts and beamflanges are often connected to columns
by field welds.
In this study, finite element method
analyses were conducted, and the effect of beam section size and beam web
connection type on flexural strengthand ductile crack initiation were investigated.

Koichiro Miyake(representative winner)
2021: M. Eng. Kyoto University2021- present: Shimizu
Corporation

Introduction
Since section sizes of members in lowand-mid-rise buildings are not so large,
the beam flange and webs are often
connected to columns by shop welds.
On the other hand, since section sizesof members in the lower floors of highrise buildings are relatively large, thebeam webs are often connected to colPin

Column(b) Sub modelBeam(a) Global model

Pin

Fig. 2 Results of Global Analysis
800
600

Bending moment of shear plate (kN・m)
Design value of flexural strength

Fig. 3 Results of Sub-modeling Analysis
Height (mm)
300

400
200

-600

0

AB

0

0

-300

Yield stress(a) Stress distribution at section A
Height (mm) Yield stress
300

Height
dir.
Axial
dir.

-600

0
-300

0

Axial dir. stress(N/mm2)600
Beam deform.
angle
0.03 rad 0.15 rad(b) Stress distribution at section B
5 Steel Construction Today & Tomorrow April 2024

0.2

Axial dir. stress(N/mm2)600
Beam deform.
angle
0.03 rad 0.15 rad

Equivalent plastic strain

Loadingpoint

Sub-modeling Analysis
The equivalent plastic strain and thestress triaxiality which are factors affecting the initiation of ductile cracks
were investigated by the local analysis
using sub-model shown in Fig. 1. The
equivalent plastic strain and the stresstriaxiality at the toe of the weld accesshole were larger when the beam section
was larger than when the beam section
was small, and the equivalent plasticstrain at the toe of the weld access hole
was larger when the beam web was connected to column by high-strength bolts
than when the beam web was connectedby weld, as shown in Fig. 3.
From these results, the following
were confirmed: In case that the beam
section was large and the beam web wasconnected to column by high-strength
bolts, the ductile crack was likely to initiate at the toe of the weld access holeearly.

0.1

Toe of theweld access hole00.6

Stress triaxiality

Fig. 1 FEM Analysis Model

Global Analysis
The flexural strength of beam web connection was investigated on sub-assemblies of beam-to-column connection by
global analysis. As a result of monotonic loading analysis using the model
shown in Fig. 1, it was found that thebending moment was approximately thesame in section A where is closest to thecolumn steel pipe wall and section B
where is the high-strength bolt hole, as
shown in Fig. 2. It was also found thatthe stress at the top and bottom ends ofsection A only reached the yield stress
but the stress at almost the entire section of section B reached the level higher than the yield stress.
From these results, the following
were found: In case that the beam web
is connected to the column by highstrength bolts, the cross section withbolt holes closest to the column skinplate yielded before the other sections,which caused that the flexural strengthof beam web connection was at mostyield moment of shear plate rather than
the full-plastic moment.

0.4
Weld Bolt

0.2

Low
High
Equivalent plastic strain

0

0

0.01

H-1200
H-800
H-500

0.02

0.03

Beam deformation angle (rad)Awards

Experimental Study on the Influence of Thin Mortar
Layer and Headed Stud Spacing of the Precast
Concrete Slab on Composite Girder Bridges

Prize winners: Takahiro Asano, Fumika Asano, Takashi Yamaguchi, Kento Ishida and Takashi Matsumoto
Takahiro Asano

2009: M. Eng. Kansai University
2009- present: West Nippon
Expressway
Company Limited

Introduction
In Japan, renewal projects are underway inwhich superannuated reinforced-concreteslabs (RC slabs) are replaced with precast
prestressed concrete slabs (PCaPC slabs).
In the design of composite girders in Japan,
the maximum bridge axis-direction spacing of the headed studs used for preventing
slip occurring between steel girders andslabs is restricted to 600 mm. However, inthe case of applying PCaPC slabs, it is difficult to arrange PC steel wire strand, andthus composite girders cannot be formed
with a headed stud spacing of 600 mm.
In addition, in the replacement ofslabs, thin mortar layer is placed between
the slabs and steel girders to be used forheight adjustment so as to prevent interference with splice plates. According to existing research in which a push-out test was
conducted, it has become clear that whencracking occurs in the thin mortar layer, theshearing strength of the headed studs lowers. However, examinations have not yet
been made of the headed stud spacing andinfluence of thin mortar layer affecting theprevention of slip of composite girders.
Study Purpose
Noticing the thin mortar layer placed at

the slab replacement and the headed studspacing, the purpose of this study is toclarify the effect of the thin mortar layer
and headed stud spacing on composition
action between steel girders and slabs bymeans of positive bending tests for thecomposite girder prepared by simulating
the practical composite girder.

the headed stud spacing of 600, 800 and
1,000 mm. Then, loading was applied tothese specimens until they caused fracture
to assess the flexibility constant relating
to the spring constant per unit length ofslip prevention and the strain distribution
inside the composite girder section.
As a result of this study, while cracking
occurred in the thin mortar layer aroundthe headed stud of the specimen for which
the slab was assumed to replace PCaPC
slabs, but in terms of the slipping limit shearing force, the specimen even withstud spacing of 1,000 mm could be evaluated as a complete composite girder.

Study Results and Conclusion
In this study, two kinds of specimens wereprepared-RC slab specimen in which theheaded stud spacing was set at 600 mm
and another specimen for which replacement is assumed of PCaPC slabs with

Photo 1 Specimen and fracture test

Fig. 1 Comparison of Flexibility Constants

1.60

Composite girder with partial interaction

1.40
1.20
1.00

Composite girder

0.80
0.60
0.40

RC
Allowable
shearing force

Slipping limit
shearing force

PCa600PCa800

PCa1000

Use limitation
Designshearing force shearing strength

Theoreticalneutral axis

Theoreticalneutral axis

Distance from lower flange (mm)PCa600PCa800
PCa1000

Distance from lower flange (mm)Theoreticalneutral axis

Distance from lower flange (mm)Distance from lower flange (mm)Fig. 2 Comparison of Strain Distribution

Theoreticalneutral axis

Strain (μ)

Strain (μ)

Strain (μ)

Strain (μ)(a) Allowable
shearing force(b) Slipping limit
shearing force(c) Use limitation
shearing force(d) Design
shearing strength
April 2024 Steel Construction Today & Tomorrow 6

Special Topic: Steel Construction Projects Overseas (1)“Tao Zhu Yin Yuan” High-rise Residential
Building in Taiwan

by Hideki Yamasaki, International Division, Kumagai Gumi Co., Ltd.
Structural Features of Tao Zhu Yin
Yuan
The high-rise residential building “TaoZhu Yin Yuan” was constructed in Taipei, the largest city in Taiwan. This steelstructure building has a height of 93.2
m, with 21 floors aboveground and fourbasement levels (Photo 1). It is composed of two residences per floor or a total of 40 residences from the 2nd floor
to 20th floor. The floor area covers 200

tsubo (about 660 m2) per residence.
The floor space on odd-numbered
floors is 25 m long from the entrance
door to the tip of the residential area.
There is a column-free space similar tothe size of an elementary school swimming pool. The exterior wall is mostly covered with glass, and when the entrance door is opened, a 135-degree
broad view spreads before residents.
A multi-functional elevator for use forcars is installed in the core area at the centerof the building, and a parking lot is provided in front of the entrance of each residence,
thereby allowing for the resident to drive his
car to the front of the entrance (Fig. 1).
Main Building Structure
The main building structure is composedof roughly five sections-seismic-isolated foundation, center core, two layer-integrated truss at the wing section, four mega-columns installed at each side of the tipof the wing, and a hat truss on the top-mostfloor to support the mega-column (Fig. 2).

• Seismic-isolated Foundation

The seismic-isolation system (Friction
Pendulum™ Seismic Isolation Bearings ofEarthquake Protection Systems of the US)
was adopted for the seismic isolation of thefoundation (refer to Fig. 3 and Photo 2).

• Wings (Two Layer-integrated

Vierendeel Truss System)
The wing section is composed of a structure in which a two-layer integrated Vierendeel truss is spanned between the centercore and the mega-column. Aesthetically,
the two layer-integrated Vierendeel truss
is rotated clockwise around the centercore by 4.5 degrees, but structurally, thetruss is rotated clockwise by 9 degrees.
The two layer-integrated Vierendeel
truss adopted in this project was regarded
as a structure having a beam depth and story height of 3.6 m per floor, and the truss
was structured in ways that connect the 25
m-long distance from the center core to

Photo 1 Full view of Tao Zhu Yin Yuan

Fig. 1 Conceptual Drawing of Floor Plan at Completion
Entrance hall:About
20 tsubo(66 m2)Porch:
About 35 tsubo(116 m2)

Fig. 2 Main Structure Model
Roof layer:
R1F~RF• Hat truss at topmost floor• Center coreMulti-functional elevator(for cars)

Standard layer:• Two layer-integrated R1F~RF
truss at wing section• Mega-column• Seismic-isolated foundation

Entrance 20 tsubo (66 m2) + Residential area 180 tsubo (594 m2) =200 tsubo (660 m2)
Public space + Parking lot = 100 tsubo (330 m2)
7 Steel Construction Today & Tomorrow April 2024

Underground layer:
B4F~1FFig. 3 Seismic Isolation of Foundation
North

Former building
undergroundstructure

Newly-installed earth-retaining wall R600 (completed)
Undergroundseismic-isolated
space 2.6 m

West

East

Undergroundseismic-isolation device
48 sets

Newly-installed
continuous
underground wall

Lower ground

Design allowablevertical displacement
70 mm

South
Building side

Upper ground

Design allowable horizontal displacement
820 mmBuilding side

Earth side

Earth side

the mega-column installed on the wing tip
using a beam with a beam depth of 3.6 m.
To that end, a column was arranged in theVierendeel truss on even-numbered floors,
and the column-free 25 m-long space wasprovided on odd-numbered floors.

• Mega-columns

Four mega-columns were spirally arranged at the tip of the wing section oneach floor. As the mega-column presentsa spiral inclination, horizontal-direction
torsional stress is generated, but this is absorbed with the outrigger truss arrangedon the topmost floor. The mega-column
was required to possess not only highstiffness but a slim configuration from the
aspect of aesthetic design, which thus led
to the adoption of 780 N/mm2-grade steel
for building structures (KBSA630 steel)as the structural material for the megacolumns. (Refer to Photo 3)

Application of 780 N/mm2-grade steel forbuilding structures

Building side

Earth side

• Hat Trusses

It was required for the topmost floor tobear the horizontal stress occurring fromthe spirally-arranged mega-column. To
cope with this requirement, a 5 m-highroof-structure truss (hat truss) systemwith high stiffness and employing diagonal braces arranged from the center core
was provided to extensively reduce thetorsional deformation occurring due to therotating configuration. (Refer to Fig. 4)
Features in Construction• Piling WorkIn the construction of this high-rise residential building, the design was madein ways that reused the existing underground building structure and drove newpiles additionally to existing piles.
As the location of the new piles was
designed based on a circular grid from thecenter of the building to match the shape ofthe building, the location of the new piles

Photo 2 Seismic isolation of foundation (Friction
Pendulum™ Seismic Isolation Bearingsof Earthquake Protection Systems of
the US)in relation to the existing piles, which had
been driven on a general square grid, had
to be fine-tuned on site after the locations
were measured using the existing as-built
drawings as a basis for placement.
Further, while pile driving is commonly undertaken on earth, the existingbuilding structure remained in the underground site, and thus examinations weremade of the installation of the temporary
platform that was exclusively used for
driving piles from the pressure-resistantslab at the existing fourth basement level.
For the platform used to drive 2.5 mdiameter piles, the sleeper and joist were
designed in a manner to avoid the new piledriving position additionally designed toa radial form. The platform framing was
irregular but appropriate, or the custommade platform was put into use.

• Earth-retaining Work Employing

Existing Building Structures
In this project, an open space having a diameter of about 76 m and no strut up to thepressure-resistant slab level at the fourthbasement level was completed by using
the existing structure up to the fourth basement level and arch effect brought about
by a newly-installed earth-retaining wall(underground continuous wall R600).
Capitalizing on the open space thus
completed, long reinforcing bars could
be arranged directly on the pressure-re-Fig. 4 Hat Truss

Photo 3 Mega-column
April 2024 Steel Construction Today & Tomorrow 8

sistant slab where the amount of reinforcing bar arrangement was largest, and thesubsequent installation of undergroundbeams at the fourth basement level used
for attaching the seismic isolation device
was smoothly undertaken. To that end,
both the construction term and cost weresuccessfully reduced. (Photo 4)• Parallel Construction Method

In the underground construction, the B4F
pressure-resistant slab, the seismic isolation of the foundation and the B4F floor
were constructed in this order, followedby the B3F floor, which would normallybe constructed next, but in this project, aparallel construction method was adopted where the 1F floor was constructed inadvance of the B3F floor.
Due to the horizontal separation of construction work at the first-floor level, theparallel construction of both abovegroundsteel-frame structures and undergroundstructures was carried out, which led to thesuccessful reduction of construction term.
In addition, the underground construction work could be undertaken safely evenagainst flying objects falling from the upper
floor while securing a carrying-in directing
line and erection space. (Refer to Photo 5)

floor concrete placement, exterior finishing, planting and other works.

♦♦♦

It is not uncommon to see scenes in which
many citizens and tourists gather aroundthe “Tao Zhu Yin Yuan” residential building, looking at it from all angles and taking pictures with their cameras and cellphones. As a member of this project, I amvery happy to see such scenes. The build-

ing is attracting attention as a new landmark in Taiwan, next to the TAIPEI 101.
Because this project was completedwith a novel and original design drawn
by an architect, and because it was a moredifficult project than any other, there wasa great sense of accomplishment. We
would like to continue to take on further
challenges capitalizing on even more advanced technological capabilities.

Photo 4 Newly-installed earth-retaining wall (completed)• Horizontal Camber

Because the four mega-columns seen in
front of the building were installed diagonally, as the building load during construction increased, it was forecast that the mega-column would tend to cause torsion in
not only vertical direction but the clockwise horizontal direction due to the deadload of the building. To cope with sucha situation, camber was provided in advance in the upper direction and the leftrotation direction by forecasting the displacement allowance at the stage of frame
erection, and in the end, camber was also
provided in not only the vertical direction
but also the horizontal direction so that themega-column would eventually return toits regular position under the condition of
application of the entire dead load.
At the position of the virtual camber line
(Fig. 5) where camber during steel framing
erection is taken into account, camber wasprovided in the upper direction on the 17thfloor section by 138.7 mm at maximum andin the left-rotation direction by 176.9 mm,
and then the steel framing was erected.
Construction was undertaken by foreseeing that the truss framing would return to the continuous-line position due
to the application of the entire dead loadat the stage of full completion of the

9 Steel Construction Today & Tomorrow April 2024

Photo 5 Parallel construction method

Fig. 5 Horizontal Camber
When the load is applied,
the mega-column tends torotate clockwise.

Special Topic: Steel Construction Projects Overseas (2)Construction of Elevated Bridges
in the Urban Area of Sri Lanka

by Takeya Inoue, Infrastructure Engineering Sector, JFE Engineering Corporation

Outline of Elevated Bridges
The elevated bridges serve as a connecting node where highways running in three directions are connected using a junction. This is the firsthighway project that is constructedin urban area with continuous elevated bridges in Sri Lanka. This roadlayout was arranged appropriately tominimize the effect of the traffic service of the existing roads. In addition, steel rigid-frame piers and steel
box girders were adopted for the section located on existing road to reduce on-site erection period. (Refer
to Photos 1 and 2)
For steel rigid-frame pier, a total of 3,500 tons of SBHS500 (500 N/
mm2-grade steel for bridge high-performance structures marketed by Japanese steelmakers) was adopted thathas high yield strength and allows the
reduction of preheating process whenwelding. This is the first application of
SBHS500 in overseas steel bridge construction project.
Fabrication of Bridge Members
Total fabrication weight of the steel rigid-frame piers, steel superstructure box
girders and slab deck panels amounts

Fig. 1 Location of Elevated Bridge Erection Site
TIn o B
te an
rn d
at ar
io an
na a
l A i kei rport

Project Outline
This project is located in the northernpart of Colombo, an economical nucleus city in Sri Lanka, and here is strategic traffic point linking the downtown
area of Colombo, second-largest city
Kandy, port of Colombo and the International Airport (Fig. 1). The existing road infrastructure was not covered
for the rapid increase in traffic and was
suffering from chronical traffic congestions. And thus, in this project, elevated bridges were constructed as bypass road in parallel with the existingroad aimed at solving traffic congestion.
The project was undertaken as a
STEP (Special Terms for Economic Partnership) project financed by
ODA (Official Development Assistance) from the Japanese Government.

Port of Colombo

Elevated bridge
erection site
India

Downtown areaof Colombo

Sri Lanka
Colombo

Photo 1 An architect’s conception of completed elevated bridges (CG)Photo 2 An architect’s conception of elevated section (CG)
April 2024 Steel Construction Today & Tomorrow 10

to 21,200 tons, for which it was necessary to complete all these members
within about 1 year and 6 months. It
was impossible to fabricate such ahuge amount of steel members by only
one fabricator, and thus it was planned
to divide the fabrication among multiple fabricators.
By comprehensively assessing the
fabricating capacity, transport performance and other factors, five fabricators in four nations (Japan, Myanmar,
Vietnam, and Thailand) were selected. The steel plates were produced bya major Japanese steelmaker and supplied to the respective fabricators. (Refer to Fig. 2)
For the fabrication of rigid-frame
piers, particularly the welding of its
corner sections, stricter quality control than that for steel superstructures
was required. To satisfy this strict
quality control, full-scale mockup
was prepared in advance to confirm
the fabrication capability of the fabricator.

The steel superstructure box girders are composed of 21 bridges, andthe total fabrication weight amounted
to 13,800 tons. These box girders were
fabricated by two fabricators related tothe contractor in Myanmar and Vietnam. Both fabricators had a full trackrecord of Japanese ODA-financed
bridge construction project and hadenough fabrication capacity. However,in order to repetitively carry out delivery of steel materials, inspection of trial assembly and transportation of fabricated member every month, precise
schedule management was held withinproject manager, designer, fabrication
supervisor and erection manager. (Refer to Photo 3)
For the deck panel of composite
slab, “River Deck” was adopted, whichuses DFT (deformed flange T-shape; Tshape with protrusions on the flange
surface) as reinforcing ribs. In addition, one-side high strength bolts wereadopted partially, in which bolts were
set in advance before erection of thedeck panel (Photo 4). As a result, it enabled to reduce scaffolding, which requires nighttime traffic restrictions
when installed.
On-site Erection of ElevatedBridgesOn-site erection of the elevatedbridge was carried out by truck-cranebent method, and no notable special
erection technologies were adopted. However, it was required to erecta total of 23,000 tons of all bridge
members within 1 year and 6 months,
and thus the project site was divided
into several areas and erection work
was carried out parallelly at each area.
As for operation of cranes, a maximum of three all-terrain cranes with
200-ton hoisting capacity and a maximum of two crawler cranes with 200ton hoisting capacity were operated simultaneously. The erection weight permonth amounted to up to 1,930 tons.
(Photo 5)

Fig. 2 Division of Fabrication
Myanmar
Superstructure
box girder
9,000 tons
Total fabrication
amount21,300 tons

VietnamSuperstructure
box girder
4,800 tons

ThailandSteel bridge pier2,000 tons
Slab panel
1,800 tons

Japan
Steel bridge pier1,800 tons

VietnamSlab panel
1,800 tons

Photo 3 Temporary assembly of bridge superstructure

Photo 4 Composite slab panel
Photo 5 On-site erection

11 Steel Construction Today & Tomorrow April 2024

On-site erection was carried out by
overcoming the following issues:• The bridge to be erected was locatedon existing road, but closing the existing road for all vehicles was impossible, and thus erection work was carriedout with partial traffic regulation limited to the nighttime when traffic wasless (21:00 pm to 5:00 am).
• It was difficult to arrange most of thetemporary materials, machinery and consumables required for construction within the cities of Sri Lanka, and thus they
had to be imported.
• The available land for erection was narrow,and thus it was hard to secure the necessary working area for on-site erection.
• Steel bridges are not widely used andskilled workers for steel bridge erection
are not available in Sri Lanka, and thus

it was essential to dispatch Japanese supervisor to provide guidance for it.
Project Supervision
The contract term for this project was
set at three years, and it was necessary
to complete the bridge foundation, substructure, superstructure, floor slab,
bridge surface work and civil engineering work within this term. To this end,
it was required not only to work in close
tie-up among design, fabrication anderection but also to seamlessly supervise
the work, and these requirements weresecurely carried out.
However, this project was forced tohalt due to two major external factors: aseries of terrorist bombings in Sri Lanka and a work lockdown due to the COVID-19 pandemic. In order to overcome

these two issues, every available measure was taken to resume the work as
quickly as possible, leading to the successful completion of the project. (SeePhoto 6)♦♦♦This project started in December 2017,and a grand opening ceremony was held
in November 2021 to mark the openingof the bridge to the traffic while overcoming many difficulties. During thisproject, we received guidance and cooperation from the Road Development
Authority in Sri Lanka, Oriental Consultants Global Co., Ltd. and many other related entities. We would like to express our deep respect and gratitude to allof them.

Photo 6 Elevated bridges uponcompletion

April 2024 Steel Construction Today & Tomorrow 12

Special Article: Stainless Steel

Large Stainless Steel Roof at Japan
National Stadium

by Hisao Kawano, Teppei Fujimoto and Masayuki Horikawa, Taisei Corporation
and Jiro Kawano, Sanko Metal Industrial Co., Ltd.
“Stadium in the Forest”
The project to construct the New National Stadium started in 2016 as part of an improvement project for the former National
Stadium in Tokyo. The design of the New
National Stadium was undertaken by a joint
venture of Taisei Corporation, Azusa Sekkei
Co., Ltd. and Kengo Kuma & Associates.
Construction started in 2017, and the stadium was completed in 2019. Then in 2021,
after going through the COVID-19 disaster,
the Tokyo Olympic and Paralympic Games
were held with no spectators in Japan, and
it is still fresh in our memory that the New
National Stadium (Japan National Stadium)was used as the venue for the Games.
The Japan National Stadium is located ona site that connects to an abundant greenerynetwork in surrounding areas, such as the
Inner Garden of Meiji Jingu Shrine and the
Shinjuku Gyoen National Garden. Looking
ahead to 100 years from now, it was planned
as a “Stadium in the Forest” that is rich withtrees and greenery and in harmony with thesurrounding environment.
Outline of Stainless Steel RoofIn finishing the large roof at the Japan National Stadium, a stainless steel metallic roof employing high-pressure cemented excelsior boards as the sheathing roof
board was adopted with the aim of mitigating solar radiation heat. The final goal wasto control the thermal environment of spectator seats located under the roof from theviewpoint of environmental considerations.
Further, in order to suppress the heatgeneration occurring at the roof, the surfaceof the stainless steel roof was finished witha color-coated stainless steel specificationof coating whitish fluorine resin (equivalent to N9 or more) conducive to enhancing the solar reflectance. In this way, proper considerations were paid to protect boththe observation and athletic environments.
Advantages of Stainless Steel Roof
Application
In addition to its high heat insulation, heatshielding and sound insulation performance,
the large stainless steel roof offers anothernotable advantage-stainless steel is easy toadapt to form the three-dimensional complex
13 Steel Construction Today & Tomorrow April 2024

Photo 1 Japan National Stadium

configuration required for the large roof. Further, waterproof performance can be secured
even for a roof with a complex configuration
by capitalizing on the integrated roof structure made available by means of the continuous seam welding of the stainless steel roof
members, and the high performance required
for the roof can be maintained while following temperature changes. In light of these advantages, stainless steel was adopted for theconstruction of the large roof.
R-T Construction Method for the
Stainless Steel Roof
The “R-T Method” is a roof waterproofing method in which a completely integrated roof structure is prepared by meansof the seam welding of 0.4 mm-thickstainless steel sheets. Sanko Metal Industrial Co., Ltd. introduced the R-T Method
in 1980, to which original improvement
measures were devised so as to be able
to meet the needs for constructing domed
and other irregularly-shaped roofs.
In the past construction of stainless steel
roofs, austenitic stainless steel was adopted. However, while austenitic stainlesssteel is high in weather resistance, it has aweakness-its thermal expansion and contraction are higher than that of other steel
materials. When such a material is applied
to a roof that causes high thermal deforma-tion, creating a design to deal with the thermal expansion and contraction that occurs
in the roof has been an issue.
In the late 1990s, highly corrosion-resistant ferritic stainless steel featuring lessthermal expansion and contraction was developed. Noticing this highly corrosion-resistant ferritic stainless steel, the roof construction method was changed from theFig. 1 Mechanism of the R-T Method
for Roof Waterproofing
T joint

Polyethylene foam
Moisture-proofing
material
Sheathing
roof
board
Through-restraint
Seam welding hanger
Enlarged figure of seam section Seam
welding
Roof
Lower seam
sectionThroughrestraint
hangerUpper seam
sectionRoof
FastenerFig. 2 From the Conventional Sliding Hanger Method to the New Through-restraint Hanger Method in Roof Construction---- Both the strength and bearing force were improved by 1.5 times over the conventional method due to the reform of the roof construction method.
Conventional and New Conventional

New

Sliding hanger method

Specification
HangerSliding-section hanger

Seam configuration

Mechanism

Roof length
Roof bearing force
Seam molding work

Example of defect due tothermal expansion/contraction@448

Up to 25 m
3,610 N/m2
@281
Necessary
Kind of rib

Rib fabrication

5,755 N/m2

Suppressionof roofmaterial
movement
and controlof thermal
expansion/
contraction

Through-restraint hanger method

Through-restraint hanger

Improvementof strengthand bearingforce
1.5 times@448
or moreRib configuration

Unlimited
5,418 N/m2
@281
8,638 N/m2
Unnecessary (seam-attached molding)Fine finishing attained by means ofStandard specification the reduction of molding material
surface distortion and weld distortion
Kind of rib Rib configuration

Small rib
Small rib

“sliding hanger method” with which thermal expansion and contraction are set free tothe “through-restraint hanger method” withwhich thermal expansion and contraction
are continuously restrained to the roof substrate. Capitalizing on the adoption of thethrough-restraint hanger method, a restriction imposed on the roofing member length
was abolished, and the strength of stainlesssteel roof was improved by about 1.5 times.
Welding Technologies Developedin the Construction of Japan
National Stadium
In 2018, a new type of welding machine wasdeveloped that serves as an essential device
for securing welding quality. Stabilized welding quality could be obtained by changing thewelding machine from the conventional AC
type to the new inverter-control type.
In addition, discussions were repeatedon the reexamination of welding machineparts and raising the voltage applied, and as
a result, the weight of the welding machine
was successfully reduced by about 15%. Also, high-quality welding could be undertaken by changing diverse kinds of weld setting systems from an analog type to a digital
type. Capitalizing on the introduction of newly-developed welding machines, the welding
quality was stabilized and improved and hardconstruction work was simplified, which thus
led to the reduction of construction terms.

♦♦♦

The construction of the large stainless steel
roof at the Japan National Stadium could
not have been achieved without trials andprofound studies by designers and those involved in construction. We would also like toexpress our deepest gratitude to the people in-

Seam configuration

Deep rib fabrication inroof molding material

volved at the Japan Sports Council, the client
who provided us with a great deal of guidance and cooperation during construction.

Deep rib©2023 Joint venture of Taisei Corporation,
Azusa Sekkei Co., Ltd. and Kengo Kuma &Associates

Photo 2 Sliding-section hanger (left) and through-restraint hanger used for through-restraint hanger method (right)

Photo 3 No use of strain-reduction method

Photo 4 Use of strain-reduction method

Photo 5 Old-type AC self-propelling welding machine(upper left) and new
inverter self-propelling
welding machine (upper
right)-Weigh reduction of the
new welding machine by
15% from the old welding machine not only
reduced the work burden of welders but alsobrought about stableweld quality.
April 2024 Steel Construction Today & Tomorrow 14

JSSC International Events (1)2023 China-Japan-Korea Tall Building
Forum in Tokyo, Japan

by Dr. Masayoshi Nakai, Director of CTBUH Japan Structures Committee; International Committee ofJapanese Society of Steel Construction
Tall Building Forum
This forum is an international conference
mainly held by academic experts andstructural engineers from China, Korea
and Japan as part of the initiatives of CTBUH (Council on Tall Buildings and Urban Habitat, headquartered in Chicago,USA) in Asia. Since it started in Shanghai in 2014, it has been held every year
except in 2020 when it was cancelled dueto the COVID-19 pandemic, and this is
the 9th forum.
The event in 2023 was sponsored by
Japan (co-organized by CTBUH Japan
Structures Committee, Japanese Societyof Steel Construction (JSSC) and Laboratory for Materials and Structures, Tokyo Institute of Technology (TIT)), 16
invitees from China, Korea, Australia
and the United States, 3 speakers fromJapan and 16 members of this committee
gathered together, and it was held on July 7th, 2023 at the Ookayama Campus of
TIT, while using online system.
Outline of 2023 ForumAt the opening of the forum, there were
greetings from Dr. Masayoshi Nakai at
Takenaka Corporation (director of thiscommittee) representing Japan, Prof.
Guoqiang Li at Tongji University representing China, and Prof. Myung Sik Lee
at Dongguk University representing Korea. They expressed their gratitude forholding a face-to-face conference for the

Photo 1 Lecture delivery from Prof. Kwok
15 Steel Construction Today & Tomorrow April 2024

first time in four years.
Prior to the lectures from each country, Prof. Yukio Tamura at Chongqing
University (vice-chair of this committee) gave a keynote lecture from the hostcountry on the research achievements
based on a series of wind tunnel experiments, including the evaluation of therelationship between the configurations
and aerodynamic characteristics of tallbuildings, such as wind load acting on
the whole building and exterior materials, human habitability against the building vibration.
Three lectures on the following topics
were given from China:• Structural design methods of tall buildings utilizing two types of generative AI:
generative adversarial network (GAN)
and graph neural network (GNN)
Current
status of performance-based seis•mic design (PBSD) of tall buildings andthe latest advancements in PBSD methods based on predetermined yield modeand member ductility requirements• Case studies on the seismic strategies,
seismic isolation scheme and energy dissipation scheme, in order to meet the requirements in the “Guidelines for Seismic Design of Post-quake Functional
Buildings” newly proposed in China.
From Korea, the following four topics
were introduced:• Design competition of urban regeneration projects creating a foundation ofstart-up culture and making local leisureinfrastructure in Seoul
Smartfire safety integrated system (ISFS)•
of public facilities using AI technology• The first performance-based fire-resistant design of 20-story office building
using CFT columns and thin steel-platecomposite beams in Korea
Analyticalresults of productivity and eco•nomic benefits of BIM-based multi-tradeprefabrication method for MEP system.
Prof. Kenny Kwok from Australia,
who received the best paper award of theInternational Journal of High-Rise Buildings in 2022, was invited to give a lectureon the recent progress in evaluation ofoccupant comfort against wind-induced
motion of tall buildings (Photo 1).
In addition, from Japan, Assoc. Prof.
Akihiko Osawa at Toyo University gave
a lecture on the history of the birth anddevelopment of tall buildings in Japan,
mainly from the perspective of the legal
system (Photo 2), Mr. Takaaki Udagawa
from Nikken Sekkei presented a structural design of office building with highdamping provided by deformation amplification mechanisms and tuned viscous mass dampers, and Ms. Ayako
Yasutomi from Shimizu Construction introduced the construction of Japan’s tallest building (officially named “Mori JP
Tower”) in the “Azabudai Hills”, focusing on DX challenges.
Approximately 120 people participat-

Photo 2 Lecture delivery from Assoc. Prof. Osawaed in this forum including online attendees, and each lecture was followed by
active discussion (Photo 3). At the closing session, Prof. Sang Dae Kim (former
president of CTBUH) and Akira Wada,
professor emeritus at Tokyo Institute ofTechnology (chair of this committee) expressed their deep gratitude for being
able to come together for the first time infour years and having a fruitful and constructive discussion, and the 2023 forum
being successfully completed (Photo 4).
Technical TourOn the day before the forum, July 6th,

Photo 3 Q & A session at the forum

a technical tour was held by participants from overseas and members of
this committee. In this tour, we visited the construction site of the “Azabudai Hills” to see its main office tower (officially named “Mori JP Tower”)
which was completed in early July of2023 and became the tallest building inJapan (approximately 330 m), commercial building and residential tower underconstruction (Photo 5). At the site, someengineers in charge of construction explained to us on the outline and current
status of construction work (Photo 6).
We also visited the “Mori Building

Urban Lab” near the construction site
to see the model of the entire construction block and the panels showing overview of the buildings in the studio (Photo 7). In addition, Mr. Toru Tsuchihashi
from Mori Building kindly made somepresentation using projection mappingin the room with 1:1000 scale city model of central Tokyo and 360-degree viewscreen.

♦♦♦In the end, we would like to express our
deep gratitude to the Obayashi Foundation for their grant in order to hold thisforum and technical tour.

Photo 4 Group photo of forum participants

Photo 6 Explanation from the construction manager

Photo 5 Construction site of the “Azabudai Hills”

Photo 7 Construction block models in the “Mori Building Urban Lab”
April 2024 Steel Construction Today & Tomorrow 16

JSSC International Events (2)13th Pacific Structural Steel Conference(PSSC2022)

by Naohiro Haneda, International Committee, Japanese Society of Steel Construction(Kajima Corporation)
Outline of PSSC2022
The 13th Pacific Structural Steel Conference (PSSC2022) was held for twodays starting from October 28, 2023
at the Century City International Convention Center in Chengdu, China under the sponsorship of the China Steel
Construction Society (CSCS). (Photo 1)
Many countries participated in the
PSSC2022, including the 11 member
countries of the Pacific Council of
Structural Steel Associations (PCSSA) and other pan-Pacific countries. A
total of 173 theses including 102 theses presented at the conference venue were submitted to the PSSC2022.
Eleven theses were submitted from Japan, and 9 were presented at the conference venue.
The theses and presentations at the13th PSSC by topic are shown in Fig. 1.
At the PSSC2022, many presentations
were made in the fields of composite
structures and disaster prevention. The
keynote lectures were delivered by 17
representatives of participating countries, and the following two keynote
lectures were delivered from Japan.
(Photos 2, 3 and 4)

Fig. 1 Theses and Presentations Submitted in PSSC2022 by Topic
Topic 1: High-Rises, Long-Span and Space Structures
Topic 2: New Type Composite Structures
Topic 3: High-Performance Steel and Metal Structures
Topic 4: Assembled Building with Steel Structures
Topic 5: Design Concepts and Methods
Topic 6: Structural Stability, Fatigue and Fracture
Topic 7: Disaster Resistance and Design
Topic 8: Artificial-Intelligence-Based Design
Topic 9: Advanced Manufacturing and Fabrication
Topic 10: Innovative Erection and Construction
0
5
10
15
No. of thesis submitted
No. of presentation at the conference venue
Japanese theses and presentations

20

25

30

35

• “Vehicle Safety against Crosswind

and Long-span Bridge Aerodynamics” by Hiroshi Katsuchi, Chairmanof the International Committee, Japanese Society of Steel Construction(Professor, Yokohama National University)• “Advancing the Global Adoption ofJapanese Steel Building Construction
Technology” by Professor Yukihiro
Harada of Chiba University

Photo 2 Keynote lecture by Prof. Hiroshi Katsuchi of Yokohama National University

Photo 3 Keynote lecture by Prof. Yukio Haradaof Chiba University

Photo 1 Opening ceremony
17 Steel Construction Today & Tomorrow April 2024

Photo 4 Venue for keynote lectures

At the PSSC2022 held in 2023, thekeynote lecture was delivered on themorning of October 28 and the afternoon
of October 29. On the afternoon of October 28 and the morning of October 29,
presentations on 10 topics were maderespectively in four conference venues.
The keynote lectures were 30 minutes
long, and each presentation at the conference venue was 15 minutes long, but
all of the lectures and presentations werefilled with enthusiasm, and many weremade right up until the very last minute.
In the evening on October 28, a welcome dinner was held, and in the morning on October 30, the participants went
on a technical tour.

In the intervals between conferences, bilateral consultations were held between the China Steel Construction Society and the Japanese Society of Steel
Construction. Specifically, mutual confirmation was made on the memorandumon the tie-up relationship between bothsocieties to promote the future innovation and development of steel-structuretechnologies and for the further diffusionof steel construction in China and Japan.
(Photos 5 and 6)
PSSC2025 in Korea
O n O cto b e r 2 7 , t h e d a y b e fo re
PSSC2022, a meeting was held among
PCSSA members, and it was decided thatthe next PSSC will be held in Korea in
2025, the year originally settled for holding the PSSC. This will be the first timein 27 years that the PSSC will be held in
Korea since the fifth conference in 1998.
At the closing ceremony, the PSSC
flag was delivered from the China Steel
Construction Society to the Korean Society of Steel Construction (KSSC), andaspirations for the PSSC2025 in Korea
were expressed from the KSSC President. Expectations are high for Japan,
particularly young engineers from Japan,
to submit a large number of theses andpresentations at the coming PSSC2025.
(Photos 7 and 8)

Toward Enhanced Ties between
China and Japan
Since the first PSSC was held in 1986 in
New Zealand, PSSC participating countries have alternated in holding the conference every three years. While the
PSSC2022 was originally to be held in
2022, it was postponed for one year due
to the need to refrain from face-to-facemeetings worldwide due to the global
COVID-19 pandemic, and as a result it
was held in 2023. It was heard that morethan 900 people from every part of China
participated in the PSSC2022, immigration screening (obtaining a visa) after the
resumption of entry permits for foreigners to China had become stricter, which
may have resulted in fewer presentations
at the conference venue from Japan.

Photo 7 Closing ceremony

Photo 5 Meeting between CSCS and JSSC

Photo 6 Participants from JSSC

Photo 8 Ceremony to deliver the PSSC flag from CSCS to KSSC
April 2024 Steel Construction Today & Tomorrow 18

Message from JSSC Executives

Message from the President of the JapaneseSociety of Steel Construction

by Mitsumasa Midorikawa, President(Professor Emeritus, Hokkaido University)
As measures to copewith global environmental issues, various
attempts to reducecarbon dioxide emissions or to achievecarbon neutrality havebecome an imminent issue globally.
These attempts, however, have proved
to be a headwind for steel structures, be-cause a large amount of carbon dioxide isemitted in the manufacture of steel products (iron). Incidentally, the amount ofcarbon dioxide generated per ton of ironproduced is not small, reaching as muchas about 2 tons.
But iron is an abundant resource, accounting for nearly one-third of theearth’s weight. The Iron Age beganaround 2000 BC and still continues to thepresent day. Unless any material appears
to replace steel (iron), the age of iron is
expected to continue for the time being.
Accordingly, there is no choice but tocontinue utilizing steel (iron). Hence, allthose involved in steel structures (bothsteel producers/structural member fabricators and users) are strongly urged tocontinue their efforts to reduce carbon
dioxide emissions.

Message from the Chairman of the International
Committee
by Hiroshi Katsuchi, Chairman, International Committee(Professor, Yokohama National University)
The Japanese Societyof Steel Construction(JSSC) has conducted a wide range of activities pertaining tosteel constructionsurveys and research,technological development, the spread ofsteel construction in Japan and overseas
and the improvement of steel construction technologies. It has also promoted
tie-ups with related overseas organizations. Aimed at spreading Japan’s steel
construction technologies and developing overseas markets, the JSSC’s International Committee took charge of editing Issue No. 70 of Steel Construction
Today & Tomorrow.
Issue No. 70 features the Special Topic of Steel Construction Projects Overseas. Two projects undertaken by Japa-

nese companies are introduced-the Tao
Zhu Yin Yuan high-rise residential building in Taiwan and an elevated highway
in Sri Lanka. In the Special Article ofStainless Steel, the large stainless steel
roof at the Japan National Stadium is introduced.
In addition, this issue introduces the
JSSC Commendations for Outstanding Achievements in 2023 in the fieldof steel construction (four projects) andtechnical paper (two papers).
In the pages about JSSC International Events, two events are reported on the2023 China-Japan-Korea Tall Building
Forum held in Japan and the 13th Pacific
Structural Steel Conference (PSSC2022)
held in China in 2023. Although the
PSSC2022 was postponed for a year due
to the COVID-19 pandemic, it was held
face-to-face as usual in 2023, where the

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 https://www.jisf.or.jp/en/index.html
Japanese Society of Steel Construction
3F Aminosan Kaikan Building, 3-15-8 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan
Phone: 81-3-3516-2151 Fax: 81-3-3516-2152
URL http://www.jssc.or.jp/english/index.html

19

participants were able to enjoy interacting with researchers and engineers in therespective countries for the first time ina while.
JSSC’s international activities, whichhave been greatly affected by the COVID-19 pandemic, have finally regained
their original form, and it has become
possible to effectively and efficiently
proceed with these activities while capitalizing on remote tools. JSSC plans tofurther promote wide-ranging international activities related to steel construction, represented by the challenge toward
carbon neutrality, which is an urgent issue that is confronting us. We would likefor everyone to understand the activities
of JSSC and would also like to hear youropinions at any time.

© 2024 The Japan Iron and Steel Federation/Japanese Society of Steel Construction
Edited byCommittee on Overseas Market Promotion, The Japan Iron and Steel Federation
Chairman (Editor): Takashi Shibuya
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: https://www.jisf.or.jp/en/activity/sctt/index.html. We welcome yourcomments about the publication and ask that you contact us at: sunpou@jisf.or.jp.