No. 59 April 2020

STEEL CONSTRUCTIONTODAY & TOMORROW

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

Special Issue

Japanese Society of
Steel Construction
JSSC Commendations for Outstanding Achievements in 2019

• Outstanding Achievement Awards

1 Nihonbashi Urban Redevelopment Project
2 Nakanoshima Festival Tower West

3 Osaki Garden Tower

Photo: Kiyohiko Higashide• Thesis Awards

4 Restraint Effect of Concrete Floor Slab on Lateral-Torsional
Buckling Behavior of H-shaped Steel Beam

5 Estimation of Fracture Strength of Welded Joints with Weld Defects
6 Low-cycle Fatigue Evaluation for Welded Joint of Shear Panel
Damper in Multiple Steel Columns

Feature Article: Pacific Structural Steel Conference 2019

7 12th PSSC Held in Tokyo
10 Technical Session

9 Keynote Lecture

11 Technical Tour

12 Corporate Exhibition

JSSC International Events

13 2019 China-Japan-Korea Tall Building Forum in Nara, Japan
14 2nd IABSE Young Engineers Colloquium
Special Article: Stainless Steel

16 268 Orchard Road

18 Kamihirai Flood Gate

JSSC International Committee

Back cover: Chairman Message
Published Jointly by

The Japan Iron and Steel Federation
Japanese Society of Steel ConstructionJSSC Commendations for Outstanding Achievements in 2019-Outstanding

Nihonbashi Urban Redevelopment Project

Prize winners: NIHON SEKKEI, INC. and Obayashi Corporation
Redevelopment of Zone A
The Nihonbashi 2-chome Category-1 Urban Redevelopment Project is a development of a Special Redevelopment District
consisting of four zones, centered on the
Nihonbashi Takashimaya Shopping Center Main Building (one of the Important
Cultural Properties) and the Category-1
urban redevelopment project.
Zone A is located on the east side of
Takashimaya, and its above-ground floors
comprise offices and retails as well as machine rooms including the certified DHC
for the entire zones. Its basement floors
comprise parking lots and machine rooms
such as heat storage tanks. (See Photo 1)
Design and Construction of Zone A
Zone A structure involves the multi-layered buckling-restrained braces alongwith the hat trusses, belt trusses and oil
dampers, appropriately arranged on themega frames, of which the columns fromthe upper floor are bent outwards at thebase of the upper structure. The seismic
performance of Zone A is 1.5 times thatof general high-rise buildings. (Fig. 1)
For the construction of the basement,
the “Inverted Construction method” wasadopted. The number of king posts was
reduced as the columns along the perimeter of the building were bent outwards
to connect to the retaining wall. The reduced number of king posts as well as
adopting the “Mega Frame Inverted
Construction method” greatly improved
the workability of underground workand shortened the construction period by
about 6 months. (Fig. 2)
The “Mega Frame Inverted Construc-tion method” is a construction method inwhich temporary trusses are constructed between the 1FL beams and the B1FL
beams to form mega frames, and the excavation is carried out while hanging theunderground columns from the megaframes. (Fig. 3)
The pedestrian bridge between Zone
A and Takashimaya was built with a cantilever structure supported from Zone A.
In order to avoid the effect of inter-layer deformation at an event of an earthquake, the L-shaped frame was plannedwith a mechanism to restrain its verticaldeformation by using liner sliders controlling the vibration induced at the endof the bridge. (Fig. 4) ￭Fig. 2 Underground Structure
4F

Zone A

Fig. 1 Above-ground Structure

3F

Hat truss
Multi-layered
buckling-restrainedbraces

2F
GL

1F
B1F

Oil dampers

B2F
36,750

BucklingrestrainedbracesBelt truss

B3F
B4F

King post

B5F
Photo 1 Full view

Mega frameFig. 3 Mega Frame

Seismic resistantdeviceFoundation

1F steel beamTemp. braces(cut&demolish)

Retaining wall
(Pilling)

Column(also asking post)

B1F temp.
steel beam
(remain)

1F steel beam
B1F temp.
steel beam

Retaining wall
(Basement
wall)

Fig. 4 Pedestrian Bridge (5F)
Importantcultural property

BeamLiner sliders
6F

Temp. brace

Hangingcolumns

5F

Temp. braces

Exp. joint

1 Steel Construction Today & Tomorrow April 2020

~15m
L-shapedcantileverAchievement Awards

Nakanoshima Festival Tower West

Prize winners: Nikken Sekkei Ltd. and Takenaka Corporation
In Osaka, a twin tower project was promoted at the site sandwiching Yotsubashisuji street, one of the major trunk roads
in Osaka, and the Nakanoshima Festival
Tower West is a high-rise building constructed as the second-phase project of
this twin tower project. (See Photo 1)
The structural plan of the building constructed as the first-phase project featured aseismically-isolated intermediate layer anda giant truss structure. For the Nakanoshima Festival Tower West, seismic resistancesimilar to that of the first-phase project was
required to be provided by the project owner. To meet such a requirement, a “low-risefloor-intensive response-control structure”
was adopted for the Nakanoshima Festival Tower West as a structural plan that secures seismic resistance similar to that of
the seismically-isolated intermediate layer.
Low-rise Floor-intensive
Response-control Structure
A total of 48 units of 6,000-kN highdamping oil dampers were arranged forthe large exterior wall of the low-rise section (first to fourth floors) of the building,which were covered with bricks. In addition, between the top of the self-standing wall from the first floor to the fourthfloor underfloor and the fourth-floor large
beam on the building’s east side, “BigWall
framing” was structured in which 4 unitsof identical oil dampers were arranged.
In this way, high-damping oil dampers
whose high damping effects have alreadybeen confirmed were intensively arrangedin the low-rise exterior brick-wall section
on the four sides. (Refer to Fig. 1)
The adoption of the low-rise floor-intensive response-control structure hasbrought about two notable merits: securement of seismic resistance similar to thatof seismically-isolated structure obtainedby arranging high-damping dampers intensively at the low-rise floors routinely applied; and no need for providing thefloors without building application purposes like the seismically-isolated floors.

Photo: Kiyohiko Higashide (Higashide Shashin Jimusho)

Adoption of Eco-friendly and Advanced Steel-structure Technologies
In the Nakanoshima Festival Tower
West, diverse eco-friendly technologies
have been applied, such as a regional airconditioning system (for the two buildings in the twin tower project) using water from the rivers running on both sidesof the project site and a double-wall glass“active skin” exterior wall attached tothe columnar-state section of the officefloor exterior wall surface.
In addition, because a heavy-traffic
expressway runs in the site and the site
is next to a trunk road, special cares wererequired to pay to falling objects during
construction. To cope with such site conditions, automated lifting-type external
scaffolding, among others, was adopted
to improve safety and productivity. Thus,
the Nakanoshima Festival Tower West isassessed as a project that has greatly contributed towards the improvement of theconstruction technologies for high-risesteel-structure buildings. ￭Fig. 1 Framing Elevation and Damper Arrangement
Hotel floors:
Outer peripheral column @4.5 m
32nd-floor truss
Pitch change of outer peripheral column+
Supression of flexural deformation
Office floors:
Outer peripheral column @3.6 m
Center core
2,000-kN oil damper (208 units)

Fifth-floor truss
Pitch change of outer peripheral column+
Supression of bending deformation

6,000-kN oil damper at “BigWall” framing

1st~4th floors
Intensive response-control layers
6,000-kN oil damper
Photo 1 Full view and low-rise section
April 2020 Steel Construction Today & Tomorrow 2

-Outstanding Achievement Awards

Osaki Garden Tower

Prize winners: Yuichi Koitabashi, Seiya Kimura, Kenichi Hirai, Yoshihide Takada, Toshihiro Hayasaka,
and TAISEI CORPORATION
Osaki Garden Tower is an office building of the Urban Redevelopment Project by Sumitomo Realty & Development
Co., Ltd., which is 114-meter-high, andthe floor area is 178,000m2 consisting of+24 floors and -2 floors (Photo 1).
Outline of the Building
In the design of the external appearance,
the building was divided in order to reduce any oppressive feeling in the surrounding residential area. Also, the color of the glass was coordinated to show auniform external appearance.
The standard floor provides open
space with outstanding views, with a mega floor office of 5,500 m2 per floor, thelargest in Tokyo, with long spans of 10.8m, ceiling height 3 m, and depth of 21 m
without columns.
Earthquake-resistant Equipment
Intensive Seismic Isolation System
The structural characteristic of the building is the column head seismic isolation on the basement B1 level coinciding
with the building layout which adopts acenter core with 10.8 m column spacing.
The main points of the structural plan
are as follows.
• Steel columns are provided receiving thelong span beams in the office space on
both sides of the corridors in the center
core, and columns are provided receiving seismic elements arranged so as tosurround the EV bank.
• By bringing together both columns on
the first floor into a transfer frame, thevertical loads collected on the columns
receiving the long span beams act asa counterweight to balance the uplift
forces concentrated in the seismic elements due to horizontal forces during
an earthquake.

By arranging the EVs face-to-facewithin 10.8 m, it was possible to arrange
the seismic resistant elements within thecore on each of the grid lines with theEVs back-to-back.
By forming a rational seismic resistant structure concentrated in the coretaking into consideration the office flowlines, in addition to adopting a seismically isolated structure, large office floors
were achieved with a high degree of freedom of planning arrangement, while ensuring high seismic performance.
Construction Method for Underground Structure
The building has direct foundations, an
RC structure below ground, and a steel

structure above ground. Therefore thebottom-up construction method was adopted below ground, using SMW andearth anchors for the earth retaining
work, so that construction of the earthworks and main frame could be carriedout in an open state, 180,000 m³ of soil
was excavated, and the 50,000 m³ underground structure was constructed in ten
months.
The structural steel erection was carried out using four tower cranes andwork proceeded with about 3,000 tonsof structural steel in a cycle of two
weeks. ￭Fig. 1 Floor Framing Plan

Steel plate wall
Seismic brace (buckling restrained brace)

EV enteringand exiting
position

Arrangement ofseismic members
concentrated in the core

130 m

Fig. 2 Lower Framing Elevation of Short Side
Seismic force

Vertical load fromthe mass of theoffice space

Fluctuating axial
loads produced
during an earthquake
in the columns withseismic members

Long-term axial
load due to the massof the office space

Seismic member(seismic wall)
Seismic isolation member(isolator)
Seismic isolation member(steel damper)

Steel plate seismic wall

Transfer steel plate wall

Position of seismic
isolation bearing

Position of seismic
isolation bearing

Isolator

Photo 1 Exterior view
3 Steel Construction Today & Tomorrow April 2020

Position of seismic Position of seismic
isolation bearing
isolation bearing

Steel U-shaped damper

JSSC Commendations for Outstanding Achievements in 2019-Thesis Awards

Restraint Effect of Concrete Floor Slabon Lateral-Torsional Buckling Behaviorof H-shaped Steel Beam

Prize winners: Yuji Koetaka, Haruna Iga, Jun Iyama and Takashi Hasegawa
Yuji Koetaka

1999: Graduated from Graduateof School Engineering,Osaka University
1999: Entered Taisei Corporation
2001: Assistant Professor, Kyoto
University

2007: Lecturer, Osaka Institute of Technology
2011: Associate Professor, Graduate Schoolof Engineering, Kyoto University

Preface
It is well known that in the composite
beams produced by connecting H-shaped
steel beams to reinforced-concrete floorslabs by the use of headed studs, lateral-torsional buckling is hard to occur because the out-of-plane displacement andtorsion of the beam upper flange are restrained by the concrete floor slab. In order to examine the lateral-torsional buckling behavior of composite beams bymeans of numerical analysis while taking into account the restraint effect ofconcrete floor slabs on beam upper flanges, it is necessary to appropriately evaluate the stiffness and strength of the lateral and rotational springs shown in Fig. 1.
Fig. 1 Restraint Effect of Concrete Floor
Slabs on Beam Upper Flange
Displacement of the upper
flange is restricted.

LateralspringRotational
springOutline of Loading Tests
In this study, targeting at a test specimen
composed of a short-length H-shaped
steel beam and a concrete floor slab (refer to Fig. 2), loading tests were conducted that simultaneously impart an outof-plane horizontal force and torsion.
Through the loading tests, the mechanical behavior, which corresponds to theforce-deformation relationship, of lateral and rotational springs shown in Fig. 1
was confirmed.
A total of 25 test specimens wereused, and among the parameters of these
specimens were the length of headed
studs, the arrangement of headed studs(one stud, two studs in a wide space or
two studs in a narrow space), the sectional configuration of concrete floor slabs
and the beam depth.

Verification of Elastic Stiffness
and Maximum Strength
In this study, the test results for the elastic stiffness and maximum strength ofbeam upper flange-concrete slab connections were extracted from the force-deformation relationship. The results obtained from the relationship between theout-of-plane horizontal force and the displacement on the beam upper flange correspond to those of horizontal springs,
and further the results obtained from therelationship between the torsional moment and the rotational angle around thebeam upper flange correspond to thoseof rotational springs.
In addition, the existing calculation
equations used to predict the elastic stiffness and maximum strength were verified, and new calculation equations were
proposed to improvesome of the existingFig. 3 Comparison of Elastic Stiffness of Rotational equations low in predicSpringstion accuracy. In particuProposal method
lar, this study made clear
Past methodthat the elastic stiffness
Specimenand maximum strength
F11Lof rotational springs obF11L+
tained from the calculaF11M
tion results correspondF11S
ed well to those obtained
F21L
from the loading test reF21M
sults (refer to Fig. 3). ￭F12L-aF12L-b
F11L-H
F11L-L

Headedstud

F11M-f
F11M-fw
Fh11L
D11L

Fig. 2 Outline of Loading Test

Ks
Ksc
(pull out) (strain)

DF11L
DF11M

Prediction
loading
Test unloading

DF11S
sF11M

1375

Specimen(up side down)(unit : mm)
300
800

Oil jack

D11L+

sF11M+sF12M

Ksc , Ks ×103 (kNm/rad)

sD11M
0

10

20

30

40
April 2020 Steel Construction Today & Tomorrow 4

-Thesis Awards

Estimation of Fracture Strength of
Welded Joints with Weld Defects

Prize winners: Hiroumi Shimokawa, Takaaki Hiroshige, Tetsuya Fujita, Haruhito Okamoto,
Yukihiro Harada and Tadao Nakagomi
Hiroumi Shimokawa

1993: Graduated from Graduate
School of Engineering,
Shinsyu University;
Entered NKK Corporation
2003: Construction Engineering
Services Dept., JFE SteelCorporation
2006: Kawagishi Bridge Works Co., Ltd
2008: Construction Materials Engineering
Dept., JFE Steel Corporation

due to notching differs from that for ductile fractures at a section that takes into
account sectional defects due to notching.
As a result, the fracture strength estimation equation pertaining to brittle factures
was structured by referring to the penetrated notch model (Fig. 1) used in linear fracture mechanics (refer to Equation(1)). In structuring the fracture strength
estimation equation pertaining to ductile
fractures, it was assumed that fractures
occur when the sectional defect section
reaches the range of tensile strength (refer to Equation (2)). As the estimated fracture strength value, Eqation (1) was compared to Equation (2), and the lower oneof the estimated fracture strength values
obtained in the comparison was to be determined as the fracture strength.

width B to penetrated notch length A,
Ak: Equivalent penetrated notch length(mm), α: Improved strength ratio, a:Notch height (mm), c: Notch length(mm), tcr: Fracture surface height (mm)(3)

Assessment of Estimated
Fracture Strength Value
Fig. 2 shows the relationship between
the dimensionless fracture strength andthe equivalent penetrated notch length
as an example of results of comparison
between the estimated value and the test
result. The mark ● in the figure shows
the test result, and the mark ○ the estimated fracture strength value. The curvein the figure shows the estimated curvefor fracture strength. It can be seen fromthe figure that the estimated value agrees
well with the test result.
It is considered that the fracture strength
estimation equation proposed in the current study allows for grasping the permissible level of defect size required to secure
the performance requirements for welded
joints, and that the equation can be applied
as an approach to judging the acceptance/
rejection of defects in ultrasonic tests. ￭Structuring of Fracture Strength
Estimation Equation
As the test data for use in structuring afracture strength estimation equation,a total of 86 weld joint specimens withpartial defects were selected from pastreferences.
In structuring the estimation equation,
it was considered that the fracture strength
estimation equation for brittle fractures

E: Young’s modulus (N/mm2), T: Test
temperature (°C), vTE: Energy transition
temperature (°C), ξ’: B/(B-2･Aeq) or
B/(B-Aeq), vEbr: Charpy absorbed energy (J), σuT: Tensile strength in fracture section at test temperature (N/mm2),
γ: Structural stress concentration coefficient, F(ξ): Dimensionless coefficient
determined by dimension ratio ξof plate

References:
1) Shimokawa, et al., Estimation of Fracture
Strength Applying Linear Fracture Mechanics, Journal of Structural and Construction Engineering (Transactions of
AIJ), No.585, pp169-175, November 2004
2) Ozawa, et al., Experimental Study ofButt Joints with Surface Defects at Welding End, Annual assembly of AIJ, C-1
Structure III, pp569-572, August 2004

Fig. 1 Penetrated Notch Model

Fig. 2 Comparison between Estimated Values and Test Results

Preface
When weld-joining the beam ends, because it is very easy to attach the tab, cases are increasing in which the alternative
tab is applied. With a welding method
using alternative tabs, a weld defect is liable to occur at the beam end, and therefore a number of fracture tests have been
conducted for weld joints having artificial defects since the occurrence of theGreat Hanshin Earthquake.
Based on the existing test results andtargeting at brittle fractures caused byweld defects occurring at the weld start/
end section, we attempted to structure afracture strength estimation equation by
the use of linear fracture mechanics.

σ

σ

B

B
A

A

A

(1)

(2)

1.4

σpr/σuT
1.2 σmax/σuT

1.0

0.8

0.8

0.6

0.6

σ

0.0

0

5

10

Ak, Aeq (mm)
15

20

25

a) Plate test specimen1)
5 Steel Construction Today & Tomorrow April 2020

30

35

0.2
0.0

:Test results:Estimated values

No.71-74
No.84-86
vEbr=79J
T-vTE=15℃

0.4

No.1-7vEbr=11J
T-vTE=-52℃

0.2

σpr/σuT
σmax/σuT

1.2

1.0

0.4

σ

1.4

:Test results:Estimated values

0

5

10

Ak, Aeq (mm)
15

20

25

b) Frame test specimen2)

30

35

-Thesis Awards

Low-cycle Fatigue Evaluation for
Welded Joint of Shear Panel Damper in
Multiple Steel Columns

Prize winners: Masaru Shimizu, Kazuo Tateishi, Takeshi Hanji, Hiroki Sugiyama, Yasumasa Soga,
Riku Adachi and Hiroshi Noda

Fig. 1 Multiple Steel Columns

Steel column

Shear panel damper

Where

25

: Local strain range at the boxing
weld toe in a scallop of shear panel: Mean shear strain range of shear
panel: Plate thickness of shear panel: Yield stress: Shear elastic modulus

Weld bead

Shear panel

20

Crack

15

Lower flange

10

Crack with a length ofseveral millimeters wasfound in experiment

5

n
atio

im

0
12

Est

14

16

18

20

ve

cur

22

24

Number of cycles [cycle]

Fig. 3 Cumulative Fatigue Damage in
Seismic Response Analysis
0.04

(2)
(3)

4δy 5δy 6δy 7δy 8δy 9δy 10δy 11δy 12δy 13δy 14δy 15δy
Stiffener

Evaluation Method for Low-cycle
Fatigue in Shear Panel Dampers
In this study, cyclic loading test on
multiple steel columns was simulated by finite element analysis in whicheven weld toe configuration was re-(1)

Fig. 2 Comparison of Crack Initiation
and Growth

Connection
part

Preface
Multiple steel columns are a highway
bridge pier erected by joining four
steel pipe columns by the use of shear
panel dampers (Fig. 1). In the event oflarge earthquakes, shear panels manufactured using low-yield point steel
absorb the seismic energy to secure
the stability of an entire bridge structure. However, low-cycle fatigue-induced cracks may occur due to therepeated occurrence of large plastic strain at the welded joint of shear
panels. In this study, an evaluation
method of low-cycle fatigue in welded joint of shear panel damper was investigated.

yses of frame structure model. As an
example calculation, the low cycle fatigue life was also evaluated for several earthquakes using Equation (1) andthe cumulative fatigue damage rule(Fig. 3). Low-cycle fatigue life calculated from Equation (1) evaluatedits life on the same accuracy or safety side compared with the calculation
using the finite element analysis. ￭Mean shear strain history
Cumulative fatigue damage
0.02
Calculated by Eq.(1)Calculated by FEA
results
0

1
0.8
0.6
0.4

−0.02
−0.04

1.2

0.2
0

5

10

Time [sec]

15

0

20

Cumulative fatigue damage degree D

2014: Finished the doctoral course, Graduate
School of Engineering, Kyoto University
2014: Assistant Prof., Graduate School ofEngineering, Nagoya University

produced. The analysis showed thatthe crack initiation and its growth
can be estimated from the local strain
range at the crack initiation point andthe cyclic J integral (Fig. 2).
On the other hand, above-mentioned finite element analysis needs
much labor and calculation times toobtain the local strain range. From theviewpoint of practical use, we constructed the relationship between thelocal strain range at the crack initiation point and the mean shear strain
range of shear panels, which can beobtained using a comparatively simple structural calculation approach.
In this study, low-cycle fatigue
crack generated from the boxing welded joints in a scallop of shear panel
was focused on. The relationship between both strain ranges mentioned
above depended mainly on the thickness of shear panel at the welded joint.
Then, an equation to estimate the local
strain range is proposed using the following equation.

Crack length [mm]2010: Graduated from Kobe City
College of Technology
2012: Finished the mastercourse, Graduate Schoolof Engineering, Kyoto
University

Mean shear strain γ

Masaru Shimizu

By the use of above equation, thehysteresis of local strain range can be
estimated from the hysteresis of mean
shear strain range, which can be obtained from the seismic response anal-

April 2020 Steel Construction Today & Tomorrow 6

Feature Article: PSSC’19 (1)12th PSSC Held in Tokyo

The 12th Pacific Structural Steel Conference (PSSC’19) was held on November
9 to 10, 2019 at the Multi-Purpose Digital Hall of the Tokyo Institute of Technology in Japan.
The Pacific Structural Steel Conference is a major initiative bringing together expertise in structural steel research, education and construction fromall around the Pacific Rim and beyond topromote cooperation among the structural steel associations and communication on development in the field ofsteel structures in Pacific countries. It
was originated in 1986 in New Zealand,followed by Australia in 1989, Japan in
1992, Singapore in 1995, Korea in 1998,
China in 2001, USA in 2004, New Zealand in 2007, China in 2010, Singapore
in 2013 and China in 2016.
The current 12th PSSC was held inJapan for the first time in nearly a quarter of a century since the 3rd PSSC washeld in Japan in 1992. At the last PSSC
held in Shanghai, China in 2016, Japan
took over the PSSC from China, andthe Specialized Committee on PSSC’19
Arrangements was established within
the Japanese Society of Steel Construction (JSSC) and chaired by JSSC President Yozo Fujino, which promoted preparations for PSSC’19. The major reason
why the PSSC’19 was decided to be heldin Japan owed to the 2020 Olympic andParalympic Games is held in Tokyo and
the PSSC-related technical tour could
thus be organized to visit the latest facilities to be used for the Games.
Major Programs of PSSC’19
At PSSC’19, the Keynote Lecture wasdelivered and the Technical Session to

Photo 1 Group photo of participants
7 Steel Construction Today & Tomorrow April 2020

Outline of PSSC’19 Programs
Date

Time

Nov. 818:00-20:30

PCSSA meeting

Multi-Purpose Digital Hall

Nov. 9(Sat.)

9:00- 9:30

Opening Ceremony

Multi-Purpose Digital Hall

9:30-10:30

Keynote Lecture

Multi-Purpose Digital Hall

Event

Venue

• Professor Jerome F. Hajjar (Northeastern University, USA)
• Professor Yaojun Ge (Tonji University, China)

Nov. 10(Sun.)

11:00-17:00

Technical Session(parallel session)

18:30-20:30

BanquetThe Capitol Hotel Tokyu

9:00-10:30

Organized Session

Multi-Purpose Digital Hall

11:00-12:00

Keynote Lecture

Multi-Purpose Digital Hall

• Professor Chia-Ming Uang (UC, San Diego, USA)
• President Mitsumasa Midorikawa (Building Research Institute, Japan)

Nov. 11(Mon.)

9:00-17:00

Technical Session(parallel session)

17:00-17:15

Closing Ceremony

Multi-Purpose Digital Hall

8:15-14:00

Technical TourTokyo Olympic facilities and Metropolitan
highway renewal project

present research papers washeld on November 9 and 10,
2019, and the Technical Tour
was held on November 11,
2019.
A total of 21 countries participated in PSSC’19, and thetotal participants numbered339 (201 from Japan, 90 from
China and so on). In the Technical Session, 232 papers
were reported. Consequently,
PSSC’19 in Tokyo was a great
success. (See Photos 1 and 2) Photo 2 Main hall at PSSC’19 venue
At the Corporate Exhibition, 26 companies and organiza- PSSC’19 venue, and many participants
tions opened exhibition booths at the visited the booths. The Technical Tour

was made to visit Olympic and Paralympic athletic facilities that were newly completed or under construction(Ariake Arena, Ariake Gymnastics Centre and Olympic Aquatics Center) aheadof the 2020 Tokyo Olympic and Paralympic Games. The tour was also madeto the site of the renewal project of theMetropolitan Expressway more than
50 years since its original construction.
With many overseas participants, thetour was at full capacity.
The Organized Session with thetheme “Toward 2020: State-of-the-art
Steel Structure Technologies for the Future of Tokyo” was planned on the day
before the Technical Tour. In advanceof holding the tour, presentations weremade at the session to introduce thetechnological issues involved in the design and construction of these latest facilities for use at the 2020 Tokyo Olympic and Paralympic Games.

ed changes are becoming more apparent, active discussions were held withthe aim of realizing resilient, sustainable
and attractive steel structures. The significance and purpose of PSSC’19 mentioned above was stressed in the opening
address by President Fujino, an excerptof which is given below:-“The general theme of this conferenceis ‘Steel Structures with Resilience andSustainability.’ Because of recent experiences of natural disasters in Japan and allover the world, ‘resilience’ is becoming
more and more important. The effects
of climate change and limited growth
are becoming evident, and ‘sustainability’ is also becoming very vital. I believethat various aspects of steel structures
will be discussed today and tomorrow inthis conference towards achieving ‘Steel
Structures with Resilience and Sustainability’ and more attractive steel structures.”-

Towards Resilient andSustainable Steel Structures
At the opening ceremony held on thefirst day of PSSC’19, with Chairman Toru Takeuchi (Professor, Tokyo Instituteof Technology) of the JSSC’s Organizing
Committee on PSSC’19 as the chairperson, JSSC President Yozo Fujino gave
an opening address representing the hostorganization (Photo 3). Then, addresses were delivered by two distinguishedguests, President Izuru Takewaki of theArchitectural Institute of Japan (Professor, Kyoto University) and Professor
Zhou Xuhong (Honorary President ofChinese Steel Construction Society, Academician of the Chinese Academy ofEngineering). An address by President
Izuru Takewaki was read by the chairperson.
The general theme at PSSC’19 was“Steel Structures with Resilience andSustainability.” In the recent circumstances in which natural disasters havefrequently occurred and climate-relat-

Banquet and Ending Ceremony
On the first evening of PSSC’19, a banquet was held at the Capitol Hotel Tokyu.
After a greeting by JSSC President Fujino, Emeritus Professor Yushi Fukumoto(Nagoya University and Osaka University), who has made great contributions
to PSSC, proposed a toast, and a banquet was held that cultivated friendshipamong PSSC participants.
At the banquet, a performance washeld of Japanese traditional folk songs
accompanied with Japanese traditional musical instruments, koto and shakuhachi, and the participants, particularly
those from overseas, listened attentively to the beautiful tones of these instruments.
Lastly, the PSSC flag was handed
over from Japan to China, the host na-

tion of the next PSSC planned to be heldin 2022. In closing the banquet, the participants parted with a promise to meetagain in China three years later in 2022.
(See Photos 4~6)
		♦♦♦

PSSC has traditionally been managed by
the Pacific Council of Structural Steel
Associations (PCSSA) composed of themembership of 11 nations, to which Indonesia (Indonesian Society of Steel Construction) and Thailand (Thailand Structural Steel Society) have joined as newmembers. On the day before PSSC’19,
the PCSSA meeting was held, where theoutline of PSSC’19 was reported and future operating plans were discussed. ￭Photo 4 Toast by Emeritus Professor Yushi
Fukumoto

Photo 5 Performance of koto and shakuhachi atthe banquet
Photo 6
Handing over of PSSC
flag from Japan to
China, the host nationof next PSSC

Photo 3 Greeting by JSSC President Yozo Fujino
April 2020 Steel Construction Today & Tomorrow 8

Feature Article: PSSC’19 (2)Keynote Lecture

On the first and second days of
PSSC’19, the Keynote Lecture wasgiven at the Multi-Purpose DigitalHall of the Tokyo Institute of Technology, the main venue of PSSC’19.
The lecture was delivered by fourworld-renowned experts in the fieldsof building construction and civil engineering from Pacific-rim nations including Japan.
In the delivery of the lecture, advanced and leading topics on the design and construction of steel-framebuildings and long-span steel bridges
were reported, an outline of which is
introduced below:■ New Strategies for
Sustainable Resilient andStructural Systems
Professor Jerome
F. Hajjar
Department of Civil andEnvironmental Engineering,Northeastern University

In recent years, a new series of structural systems has been developed fordesigning sustainable and resilient
steel and composite steel/concrete
structural systems.
This paper summarizes research on
systems developed to reduce the energy,
pollution, and waste generated by construction and use of buildings, including
systems that enable Design for Deconstruction and systems that break thermal
bridges in steel structures.
■ Dynamic and Aerodynamic
Challenges of Long Span
Steel Bridges
Professor Yaojun Ge
Department of Bridge
Engineering, SLDRC, Tongji
University

With the formidable increase of span
length, dynamic and aerodynamic
challenges of long span steel bridges have been presented in the aspects

9 Steel Construction Today & Tomorrow April 2020of dynamic characteristics of cablestayed bridges, aerodynamic stability of suspension bridges and vortexinduced vibration mitigation of steelarch and girder bridges. Fundamental frequencies do not decrease rapidly with the increase of span length ofcable-stayed bridges, and critical flutter speed is not so sensitive to span
length, which may support to makefurther span length enlargement in thenear future.
Long span suspension bridges havebeen identified with the most challenging problem of aerodynamic instability, and one of three kinds ofcontrol measures, including stabilizers, slot and the combination of slot
and stabilizer, has to be adopted forthe span length over 1,500 m. Long
span arch bridges and girder bridges with steel box ribs or steel box
girders may have vortex induced vibration problems due to bluff crosssection of ribs or girders, but aerodynamic countermeasures and mechanical TMD can help to mitigate VIV
performance.
■ Research on Seismic Designof Deep Wide-Flange Steel
Columns in the U.S.
Professor Chia-Ming
Uang
Department of StructuralEngineering, University ofCalifornia, San Diego

Designers in high seismic regions in the
U.S. routinely use deep wide-flange columns for Steel Special Moment Frame
design nowadays, a practice which deviates from that prior to the 1994 Northridge, California earthquake.
This paper presents history of deep
column issues that first surfaced in
testing of moment connections, results from a numerical simulation that
led to a comprehensive NIST-sponsored research program involving cyclic testing of more than 45 large-sizecolumns. Findings from this program
including implications to AISC Seismic Provisions will be presented.

■ Inelastic Deformation Capacity of Steel Beam-end Connections and a Full-scale Threestory Steel Moment-resisting
Frame under Cyclic Loading
Dr. Mitsumasa
Midorikawa
President, National Researchand Development Agency,
Building Research Institute

When super-high-rise steel buildings
suffer the long-period and long-duration (long-period/duration) earthquake ground motions, it is predictedthat they will undergo numerous cyclic loadings than expected from theconventional seismic design. Since
there was insufficient knowledge on
the seismic performance and evaluation method of super-high-rise steelbuildings under such many cyclicloadings, the joint research project inJapan was launched in 2010.
In this paper, presented are the tests
on steel beam-end welded connections
and the test on a full-scale three-story
steel moment-resisting frame, whichwere performed in the project. The
multilevel cyclic loading tests on the
beam-end connections were carriedout in order to establish the evaluation
method of the cyclic deformation capacity of beam-end connections. The
multilevel cyclic loading test on the
full-scale steel moment frame was
performed in order to verify the seismic performance of the steel frame
and to confirm the validity of the fracture evaluation formulae. From thetest results of the steel beam-end connections and the full-scale steel moment frame, the fracture evaluation
formulae are proposed and verified interms of the limit number of loading
cycles until the beam-end fracture forthe seismic design of super-high-risesteel buildings against the long-period/duration earthquake ground motions. ￭(Source of the texts: Reprinted from theabstract of respective papers deliveredby four lecturers at the Keynote Lecture)

Feature Article: PSSC’19 (3)Technical Session

In the Technical Session of PSSC’19, a
total of 228 papers were reported at 41
sessions. Table 1 shows the names ofthe sessions and the number of papers
in each session.
Because of the regional peculiarity
derived from the conference namePacific Structural Steel Conference(PSSC), many papers were reported
that treated the earthquake, and thus thenumber of papers on earthquakes presented in the Session on Seismic Performance & Design was 45, the largest in the Technical Session. Following
this session, many papers were reported in the Technical Session on Connections, Design Concept and Fatigue &Fracture.

Papers on Seismic ResistanceIn the field of seismic design, papers
targeting building structures accounted for a large share. Regarding research themes, a lot of research papers
were reported that treated research on
the response-control device, the seismic resistance of column-beam-bracestructural systems, the behavior ofbeam-column joints during cyclic loading and the seismic design of gymnasium ceilings.
In particular, regarding research on
response-control devices, the development of seismic-control devices withimproved functions such as bucklingrestrained braces, viscoelastic dampers
and friction dampers was introduced,
and seismic design methods employ-

Photo 1 Scene at Technical Session

ing these devices were also proposed.
In this way, it was shown in the Technical Session that R&D on response-control devices is being actively promoted.
(See Photo 1)

Session on Connections
In the Technical Session on Connections, 31 papers were presented, of
which papers treating bolt joints accounted for a large share, but several papers on welding joints were also reported. The papers on bolt joints
included friction coefficients, bearing
strength and other basic properties ofbolt joints; research on bolt joints employing new blind bolts and those functioning as a friction damper and produced by the use of belleville springs;
a paper on beam-column joints; and the
behavior of beam-column joints andcolumn-base connections during cyclicloading. Regarding the report on welding joints, a paper investigated the residual stress of orthotropic steel decks
for bridge.
In the Technical Session on Connections, a lot of research papers relating to behavior during cyclic loadingwere reported with the target placed on
the application of research results into
seismic design.

		

♦♦♦

Active Q&A on the report of research papers was held (Photo 2), and the two-day
Technical Session on the whole ended
successfully. ￭Table 1 Sessions and Number ofPapers Reported at PSSC'19
SessionNumberof papers

Seismic Performance & Design

45

Fatigue & Fracture

15

High Performance Steel &Special Materials

12

Spatial Structure

7

Connections

31

Design Concepts

16

Structural System

13

Wind Effect5

Buckling & Stability

14

Bridge10

Robustness, Redundancy &Resilience

3

Inspection & Monitoring

10

Construction

4

Applied & Computational
Mechanics

6

Composite Materials & Elements

13

Dampers & Isolators

6

Corrosion4

Welding

7

Fire Resistance

7

Total

228

Photo 2 Active Q&A held

April 2020 Steel Construction Today & Tomorrow 10

Feature Article: PSSC'19 (4)Technical Tour

Construction is rapidly proceeding of various kinds of athletic stadiums and othersimilar facilities ahead of the 2020 Tokyo
Olympic and Paralympic Games (Tokyo
2020). As one of the events involved in
the PSSC (Pacific Structural Steel Conference) 2019 held in November 2019,
the Japanese Society of Steel Construction (JSSC) planned a technical tour that
visited not only these stadiums and facilities but also the site of the renewal project
for the Metropolitan Expressway, a trunk
expressway network running in metropolitan Tokyo and its neighboring areas.
In conjunction with the main theme of
the Organized Session held on the final
day of PSSC’19-”Toward 2020: Stateof-the-Art Steel Structure Technologies
for the Future of Tokyo,” a technical tour
was made to the site of advanced construction projects on Monday 11 November, theday after the session. The total participants
numbered 54, of which about a half wereoverseas participants. On the tour day,while it looked like rain in the early morning, it stopped raining when the tour started
and was warm in the daytime, thereby offering a really fine day for the tour.
Major Inspection Sites
The tour started from Shinagawa Station
and reached the Ariake area where Tokyo
2020-related facilities was completed orare being constructed.
First, the participants inspected the
Ariake Gymnastics Centre. Thanks to
The Tokyo Organising Committee of the
Olympic and Paralympic Games, an interior inspection was possible, and the participants were able to inspect the Centre in
the situation in which preparations are being promoted for the first event there. For
the Ariake Gymnastics Centre, design ismade so that a beautiful large-span wooden roof framing is realized employing acomposite beam strings structural system by the use of both beam strings structure and cantilever trusses. The interior inspection conducted was the best part forthe participants. (See Photo 1)
Then, the participants visited the structural periphery of the Ariake Arena and the
Olympic Aquatics Center while receiving
explanations from the engineers involvedin structural design and construction.
While the seismically-isolated roof framing with a large span surpassing 100×100
meters has been adopted for both facilities,
the framing plan and construction method
differ from each other. Specifically, in the
Ariake Arena, roof framing is composed ofone-way steel trusses arranged with a spacing of 6 meters and each truss is supported
by seismic-isolation devices at both ends.
On the other hand, in the Olympic Aquatics Center, roof structure consists of two-

directional steel trusses and is supported at four corners, where seismic isolators
are installed between the roof and the core
megastructure. The technical tour made bycomparing these structural systems wasvery interesting for the participants.
Lastly, the participants made an onsite visit to the renewal project for Root
1 Haneda Line (Higashi Shinagawa Section etc.) of the Metropolitan Expressway.
In the project, existing viaducts are being removed by providing temporary detour roads with new expressways erectedin their place. The renewal step of the expressway in service seemed complicatedin terms of time-series basis, but the onsite visit was instructive for the participants because they could understand theoverall content of the renewal project byinspecting the renewal conditions while
walking on the expressway. (See Photo 2)
Significant Technical Tour
Because the engineers involved in construction attended at each site, active
Q&A were held and efficient site tours
were accomplished in a shorter time. To
that end, the current technical tour wasassessed as a significant one.
JSSC expresses its deep gratitude tothose who made on-site preparations to
accept the tour and gave technical explanations in spite of their tight schedules. ￭Photo 1 Technical tour to Ariake Gymnastics Centre, one of major facilities for 2020
Tokyo Olympic and Paralympic Games

Photo 2 Technical tour to the renewal project for Route1 Haneda Line of Metropolitan Expressway

11 Steel Construction Today & Tomorrow April 2020

Feature Article: PSSC’19 (5)Corporate Exhibition

Opening of Exhibition Booths
In order to introduce the latest steel
construction technologies in Japan tooverseas participants at PSSC’19, theJapanese Society of Steel Construction (JSSC) recommended to open exhibition booths at the PSSC’19 venue
for structural design offices, general contractors, steelmakers, structuralmember makers, developers and infrastructure operating companies/organizations with proven records in theirrespective fields. At JSSC’s request, a
total of 25 corporations and 1 organization opened exhibition booths. The
specific exhibiting corporations andorganizations were as follows:
Exhibiting Corporations andOrganizations
Nikken Sekkei Ltd., ARUP, Mitsubishi
Jisho Sekkei Inc., Kozo Keikaku Engineering Inc., Obayashi Corporation, Kajima Corporation, Kumagai Gumi Co.,
Ltd., Shimizu Corporation, Taisei Corporation, Takenaka Corporation, JFE

Steel Corporation, Nippon Steel Corporation, Nippon Steel Engineering Co.,
Ltd., Nippon Steel Metal Products Co.,
Ltd., Tomoe Corporation, Okabe Co.,
Ltd., Kyushu Daiichi Industry Co., Ltd.,Hamanaka Nut Mfg. Co., Ltd., ProgressTechnologies Inc., IHI Infrastructure Systems Co., Ltd., East Japan Railway Company, Metropolitan Expressway Company Limited, East Nippon Expressway
Company Limited, Central Nippon Expressway Company Limited, West Nippon Expressway Company Limited, SOFTeck of Tokyo Institute of Technology

Successful Exhibitions
In the exhibition booths, steel construction technologies, steel structural
materials and typical construction projects employing these technologies andmaterials were introduced, which wereoriginal to each respective exhibiting
corporation and organization. Photos
1~3 show the exhibition booths and exchanges of views between PSSC participants.

Twenty-five corporations and one
organization opened exhibition booths
separately in front of the PSSC’s main
venue and in the coffee-break room. A
number of presenters visited the booths
between presentations, and many participants dropped in at the booths on
the way to make arrangements, which
resulted in a brisk exhibition. (SeePhotos 4~5)
In addition, exchanges between
neighboring booths were positively
promoted, and further it appeared thatexhibits were introduced between exhibiting companies and business cards
were exchanged. Those who were in
charge of explanations at the booths
gave some comments on the exhibitions, such as: “At the two-day exhibition, we had the chance to deliberately
talk with people whom it is normally difficult to meet even when visiting
their companies.” As stated above, it
was generally accepted that the corporate exhibitions at PSSC’19 were successful. ￭Photos 1~3 Exhibition booths and exchanges of views between PSSC participants

Photos 4~5 Exhibition room and exhibitions

April 2020 Steel Construction Today & Tomorrow 12

JSSC International Events

2019 China-Japan-Korea Tall Building
Forum in Nara, Japan

by Dr. Masayoshi Nakai, Director of CTBUH Japan Structures Committee,
International Committee of Japanese Society of Steel Construction;
Engineering Fellow, Engineering Department, Takenaka Corporation
The 6th China-Japan-Korea Tall Building Forum was held on July 5th 2019 in
an ancient city, Nara, Japan. This forum
was organized by CTBUH Japan Structures Committee, International Committee of the Japanese Society of Steel Construction (JSSC) in collaborations with
China International Exchange Committee for Tall Buildings and Korean Council on Tall Buildings and Urban Habitat.
The theme for this year’s forum was“Visiting Old, Learn New.” The opening
addresses were given by Dr. Masayoshi
Nakai as the director of CTBUH Japan
Structures Committee, Prof. Guoqiang
Li from Tongji University as the representative of China and Prof. Myungsik
Lee from Dongkkuk University as therepresentative of Korea.
Following the opening addresses, ninepresentations on the latest topics as summarized below were made from China,
Korea and Japan. At the same time, thisevent fostered animated and meaningful discussions with more than 80 participants including 11 from China, 13 from
Korea, 1 from US and 1 from Singapore.
Major Presentations in 2019 ForumIn the morning session, Prof. Xuhong
Zhou from Chongqing University introduced the development of steel-tubed
concrete structures, termed STRC andSTSRC, and their applications to several
high-rise buildings in China. Dr. Kwangryang Chung from Dongyang Structural Engineers Co., Ltd. provided analytical studies and structural designs ofouter mega braced frame systems for

Photo 1 Forum venue, Todai-ji Cultural Center
13 Steel Construction Today & Tomorrow April 2020

two tall buildings currently projected
in Seoul. To conclude the morning session, Mr. Yoji Ishibashi from Mitsubishi Jisho Sekkei Inc. presented a performance-based seismic design of a 212
m-high overhanging building tentatively
named “Tokiwabashi Tower-A” in which
the “Lower Stories Concentrated Vibration Control System” using oil dampers
and viscous wall dampers was installed.
Meanwhile, the venue of forum, the“Todai-ji Cultural Center,” was located in the ground of Todai-ji Temple sothat all participants visited Todai-ji Great
Buddha Hall at lunch break. (Photo 1)
In the afternoon session, Mr. Lishan Xufrom China Construction Third Engineering Bureau Group CO., LTD. introduced
key construction technologies of “China
Zun” in Beijing, such as integrated construction platform, the Jump-Lift Elevator, temporary-and-permanent fire protection system, BIM application and so on.
Prof. Hong-Gun Park from Seoul National
University provided analytical and experimental studies on corner steel-plate-reinforced RC core wall system for highrise buildings. Lastly, Mr. Takumi Tsushi
from Takenaka Corporation presented astructural design of a residential high-risebuilding tentatively named “Toranomon
Hills Residential Tower” using the ultrahigh strength 120-130 MPa concrete withsteel fibers and more than 750 vibration
control viscous and friction walls.
After the coffee break, Mr. Lianjin Bao from East China Architectural Design & Research Institute introduced two supertall connected buildings
currently projected in China and mentioned their structural solutions and connecting effects. Prof. Jinkoo Kim from
Sungkyunkwan University provided thebuilding damages due to Pohang earthquake in 2017 and the following development of seismic retrofit devices suchas corner rotational friction damper, steel
slit damper, slit-friction hybrid damperand so on. The final presentation featured
Mr. Takashi Kato from Kajima Corporation, who presented a structural designof a 192 m-high building named “Hibiya

Mitsui Tower” using newly-developed
high-performance oil dampers with theworld’s first energy recovery system, bywhich the energy absorption efficiencyof the building can actually reach 4 times
that by conventional dampers.
At the closing address, as the chairman of CTBUH Japan Structures Committee, Professor Emeritus Akira Wada at
Tokyo Institute of Technology expressed
deep gratitude to the gathering of many
people and for a constructive meeting,and this year’s forum being successfully completed.
(Refer to Photos 2~6)

Photo 2 Forum information signboard

Photo 3 More than 80 participants joined the forum

Photo 4 Lecture delivery from Prof. Zhou

Photo 5 Closing address from Prof. Akira Wada

The first was the Horyu-ji Temple
which was established in the 7th century
and designated as World Heritage in 1993.
The National Treasure, “Five-story Pagoda” in Horyu-ji Temple with a height of
32.5 m is the world oldest five-story timber pagoda in existence. (Refer to Photo 7)
The other was the Yakushi-ji Temple. The National Treasure, 34.1 m-high“East Pagoda” in Yakushi-ji Temple
built in the early 8th century is the tallest
three-story timber pagoda in designated cultural property, and currently underrestoration work. Especially, participants
were granted special access by Nara Prefecture and Yakushi-ji Temple to visit therestoration site of the “East Pagoda” andsee the ancient pagoda really up close. It
was a valuable and memorable experience for all delegates. (Refer to Photo 8)

The central column disconnectedfrom wooden framework of pagoda becomes an important model for vibration control of recent high-rise structures
such as the “Tokyo Sky Tree.”In advance of this tour, Prof. Toshikazu Hanazato from Mie University made a
lecture on the seismic and wind-resistantperformances of five-story timber pagodas as one of his specialized researches.
His kind support was greatly appreciated.

♦♦♦♦♦

In the end, we would like to express deep
gratitude to the Obayashi Foundation for
their grant, and to Nara Visitors Bureau
for their great support and cooperation
for this forum.
The 7th China-Japan-Korea Tall
Building Forum will be held in Nanjing
in September 2020. ￭Photo 6 Participants to the forum“Visiting Old, Learn New”
On the next day after the forum, July 6th,
approximately 40 delegates from China,
Korea and Japan participated in a oneday tour to two ancient temples in Nara,
following the theme of this forum “Visiting Old, Learn New.”

Photo 7 “Five-story Pagoda” in Horyu-ji Temple

Photo 8 The restoration site of “East Pagoda” inYakushi-ji Temple

The 2nd IABSE Young Engineers
Colloquium in East Asia, Tokyo 2019by Shunichi Nakamura, Tokai University, Vice President of IABSE
The IABSE Young Engineers Colloquium (YEC) in East Asia is jointly organized by the Japanese, Chinese, Koreanand Hong Kong Groups of IABSE. Following the 1st YEC held in October 2018
in Shanghai, the 2nd YEC was held on
November 7-8, 2019 at Tokyo Instituteof Technology, Tokyo. Prof. Yozo Fujino (Chair of the Organizing Committee)
made a welcome speech at the opening
ceremony. The Japanese Society of Steel
Construction (JSSC) serves as a secretariat of the Japanese Group of IABSE (International Association for Bridge andStructural Engineering).
IABSE activities provide useful andeducational opportunities for young engineers. YEC in East Asia was initiated
so that young engineers can participate
in these activities more conveniently

with much lower cost both in travel expenses and registration fees (about 1/10of the conventional symposium). Furthermore, this event encourages young
engineers to be more actively involvedin IABSE activities. At this YEC Tokyo
there were 99 participants from not only
East Asia but also Europe and Southeast
Asia (Photo.1).

Photo 1 Presenters and participants

Programs of 2nd IABSE Young
Engineers Colloquium
The program included the keynote lecture, the technical sessions and the design competition sessions. The keynote
lecture, titled “Innovations for sustainable bridge construction,” was given by
Dr. Akio Kasuga (Photo.2), an executive
vice president and CTO of Sumitomo

Photo 2 Keynote lecture by
Dr. Akio Kasuga
April 2020 Steel Construction Today & Tomorrow 14

Mitsui Construction. He has designed
more than 200 bridges and is currently
deputy president of fib (Fédération internationale du béton). The lecture shows away to sustainable bridge construction
with non-metallic and long-life bridges.
It was useful and educational for young
engineers.
The design competition was held
for footbridges which was assumed
to cross over the Sumida River witha river width of 160 m. Various typesof bridges were proposed such as suspension bridges, arch bridges, truss
bridges, floating bridges with different
construction materials such as steel,concrete and timber. The first place of
the Design Award was conferred to a
stress-ribbon bridge stiffened with archribs (Photo 3) designed by the Tongji
University Team, Zhanhang Liu, Ao
Wang and Lanxin Luo, China (Photo4). The two runners-ups were the floating timber bridge designed by the Seoul
National University student, Rudolf T.
Starossek, Korea, and the suspension
bridge with PC girders designed by the
Sumitomo Mitsui Construction Team,
Hoang Trong Khuyen, Rankoth Kumara Chamila and Enrique Corres Sojo,
Japan (Photo 4).
At the technical sessions, a total of
42 young engineers (15 from Japan, 21
from China, and 1 from Korea, 2 from
Hong Kong, 1 from Thailand, 1 from
Viet Nam and 1 from Germany) presented interesting research papers andtechnical reports of construction proj-

ects. The topics covered wide aspectsof structures: design and construction of bridges, buildings and tunnels,
health monitoring, structural materials,
design against winds and earthquakes,
fatigue and durability, and so on. After presentations were finished in a session, all of the presenters were back onstage and Q&A and discussions werecarried out between presenters and audience, which was very active (Photo.5).
The Outstanding Presentation Awards
were conferred to three presenters(Photo 6): Ms. Dorina Siebert (Technical University of Munich, Germany),
Ms. Sanako Kato (Gifu University, Japan) and Mr. Biao Tan (Tongji University, China).
The technical boat tour was carriedout to see bridges over the Sumida River in the afternoon on the second day(Photo 7).
3rd IABSE Young Engineers Colloquium
The 3rd IABSE Young Engineers Colloquium in East Asia will be held at Seoul
National University, Korea, on 11 and 12
November 2020. ￭Photo 3 The First Place Footbridge of Design Competition

First Place Team
Photo 4 Winners of design competition

Runners-up

Runners-up Team
Photo 6 Awarded Three Outstanding Presenters

Photo 7 Bridge boat tour on the Sumida River
Photo 5 Discussion with presenters and audience
15 Steel Construction Today & Tomorrow April 2020

Special Article: Stainless Steel

268 Orchard Road

-Stainless Steel Glass Box Façadeby Tomomi Kanemitsu, Hidemi Nakashima and Masaki Yamada, Shimizu Corporation

Structural Design
The building has twelve stories with
72 m height and one basement. The
building consists of a three-steppedmain structure, façades and a front
entrance with a canopy. The glassbox is formed of plate glasses supported on the stainless steel latticeframe (Fig. 1).
The roof structure is formed by thelattice frame, the struts and the net
structure. The cross sections of thelattice frame, the struts and the tension net are the v-shaped section, thepipe section and the circular section(rod) respectively (Fig. 2). In the design of the tension net, only tensile
force is considered, therefore, thePhoto 1 Exterior and interior views

members of the tension net can beslender.
The wall structure is formed by thecolumns, the horizontal beams, thestruts, the bow strings and the wall
support rings (Fig. 3). In the designof the strings and the rings, only tensile force is considered, therefore,
the members can be slender.
The material of the members of theglass boxes is stainless steel. Selection of material is based on the design

Fig. 1 Outline of Front Façade

33.3 m22.9 m
11th floor

11 m

23.4 m9th floor
7th floor

Cantilever
slab

11 m

5th floor
3rd floor

23.4 m

76.04 mIntroduction
Building façades are important aspect from the design standpoint.
Glasses are often used for expressing
transparency of the façades. In Singapore, a commercial building with alarge glass box façade was completed in 2015 (Photo 1). The façade consists of three boxes with glass roofs
and glass walls. The frames supporting the glasses are made of stainless steel. They are formed of slender
members and neat joints and fabricated by digital technology. The façade design concept of transparency
is realized by the glasses and special
frames with its material, structural
system and digital fabrication.

16.5 m7th floor plan

Fig. 2 Vertical Load Resistant Mechanism

Fig. 3 Horizontal Load Resistant Mechanism

A

80

80
y

Fixed on main structureA

Roof beam (Lattice frame)

Self-weight andwind load (downward)
Compression

Strut

Tensiony
Beam*1P-60.3×2.77*1

TensionA-A section

Tension net

Rod Φ 30*

Column*1

A2*1 SUS316LN *2 SUS2205 Duplex

Wind load(Negative)

Wind load(Positive)

13.25
x

195

150

x

A

80

150
Horizontal
beam*1Wall support ring(Rod Φ 30*2)

Bow string(Rod Φ 20*2)
A-A section*1 SUS316LN *2 SUS2205 Duplex

April 2020 Steel Construction Today & Tomorrow 16

concept of structural safety, corrosion resistance and construction performance. The materials with both
high strength and high corrosion resistance are used in the main structural members considering reductionof the sizes of the cross sections andsustainability.
Photos 2 and 3 are examples ofthe frame joints. In the design of thejoints, the followings are considered:• The structures of the glass boxes arestable in strength and in stiffness;(a) Upward view
Photo 2 Joint of roof beam

• Jointing works in the construction

field are easy;• The appearances of the joints meetthe design concept of transparency
The flexible stiffnesses of thejoints are designed through buckling
analysis.
Construction
The strength and the stiffness ofthe glass box structures depend on
pre-tension values installed into themembers of the tension structures.
The frames supporting the glass-(b) Downward viewes deform by pre-tensioning. Therefore, the glasses are installed after
pre-tensioning. The self-weight of
the glasses deflects the roof frames
downward. The downward deflection needs to be managed for providing drainage slope of the roof
surface. The dimensional accuracy of the members and the joints affects the erection accuracy. From theabove, the management of pre-tensioning and the dimensional accuracy is critical in the construction process.
Processes in the shop fabrication
are mainly machining and assembling by welding. Shop drawings areproduced using 3-dimensional CAD.
Digital data of the shop drawings aretransmitted directly to machining facilities (Fig. 4).
Critical control points of welding
are as follows:• Select appropriate welding methods including selection of welding
material;• Select certified skilled welders;• Conduct appropriate inspections in
the welding process
Especially for site welding, many welding tests simulating the actual conditions of the construction site
are performed (Fig. 5). ￭Photo 3 Joint of tension rod

Fig. 4 Digital Fabrication
Machining

DesignBIM

Fig. 5 Welding Management

3D printing

Measurement by
3D scanner

Laser cutting

Measurement
Measurement by
3D scanner(a) Shop welding test(b) Ultrasonic test

Cutting work
Temporary assembly

Facing(c) Field welding test
*Finishing is done after welding.

17 Steel Construction Today & Tomorrow April 2020

Kamihirai Flood Gate

-Retrofitting by the Use of Alloy-saving Duplex Stainless Steelby Yuji Shuto, IHI Infrastructure Systems Co., Ltd.
The Kamihirai flood gate, located at thejuncture of the Nakagawa River and the
Ayase River in the suburbs of Tokyo, wascompleted in 1970 to prevent the runningup of high tides. In the current retrofitting
project, the flood gate is entirely renewed
and seismically retrofitted so that the gate
can retain its function as a flood gate andprevent inundation due to tsunamis evenin cases when the possible maximumscale earthquake will occur. (See Photo 1)
The flood gate adopts a pipe Vierendeel-type structure, the only such example
in Japan, and in its retrofitting project, an
identical type is adopted.
Outline of Gate Structures
Alloy-saving duplex stainless steel (JISSUS323L) was adopted as the structuralmember for the gate structure in the current retrofitting project. Because the floodgate is located in a brackish water zone, it
is required for the structural member foruse for flood gate to possess pitting corrosion resistance. Alloy-saving duplex
stainless steel offers high performancethe steel has pitting corrosion resistance higher than that of SUS316L and astrength about twice that of SUS316, andin addition its cost is lower than SUS316.
Another advantage brought about by
the use of alloy-saving duplex stainlesssteel is no need for coating in practicalapplications. It is known from comparison study results that, when a 50-year
life cycle is taken into account, the lifecycle cost of this stainless steel is better

Outline of Renewal Project

Project owner: Tokyo Metropolitan
Government
Project name: Seismic retrofitting of
Kamihirai flood gate
Scope of work: Gate structure, gate stop,
opening/closing device,
operation control
equipment, operation bridge
Location: Katsushika-ku, Tokyo
Total weight: 2,150 tons

than that of ordinary carbon steel (SS400
steel for general structure+coating) having the lowest initial cost.
Manufacture of Gate Structures
The temporary assembly of the gate structure is commonly undertaken setting theskin plate to the upper side. Because a
special structural system called the pipe
Vierendeel structure (arch girder for the

Outline of Flood Gate

Type: Pipe Vierendeel-structure steel roller
gate
No. of gate: 4
Span length: 30.000 m
Gate height: 11.100 m
Lift: 8.900 m during operation, 9.700 m
during maintenance/inspection
Water seal system: Both-side three edges
rubber seal
Opening/closing system:
1-motor, 2-drum wire rope winch system(attached with self-weight closing function
by means of hydraulic control)
Opening/closing speed:
1.0 m/min
3.3 m/min (high speed) and 1.0 m/min(low speed) during self-weight closing

girder side) is adopted, temporary assembly is undertaken setting the skin plate to
the lower side and the arch girder to theupper side (Photo 2).
(Continued overleaf)

Photo 1 Full view of the flood gate before retrofitting (from upper stream side)

Fig. 1 Three-dimensional Modelof Gate Structure

Photo 2 Temporary assembly at fabrication plant
April 2020 Steel Construction Today & Tomorrow 18

On-site Installation
The retrofitting project is proceeding inaccordance with the following installation plan. Specifically, each one of a totalof 4 gates is installed throughout the year
in a dried environment using steel temporary cofferdams while making possible the operation of 3 gates in flood season and 2 gates in the non-flood season.

• Removal of Operation Bridges

In the removal of operation bridges, theentire operation bridge structure is hungout by means of a co-hoisting method
using two 200-ton hoisting crane barges and without dividing the operating
bridge structure (Photo 3).

Photo 3 Removal of operation bridge• Installation of Gate Structures

The gate structure is carried on to thesite by dividing the total structure to 10
blocks on skin plate side, 3 blocks ofarch girders and arch supporting members depending on the transport condition. Photo 4 shows the present renewal
conditions. ￭Photo 4 Current on-site condition

JSSC International Committee

Message from Chairman

by Hiroshi Katsuchi, Chairman, International Committee (Professor, Yokohama National
University)
JSSC has conducted
a wide range of activities in the form ofsurvey, research andtechnological development aimed at promoting the spread ofsteel construction and at improving associated technologies, and at the sametime it has extended cooperation to related overseas organizations. Aimed at
spreading steel construction technologies of Japan and developing overseas
markets, the International Committee of
the Japanese Society of Steel Construction (JSSC) was responsible for the edi-tion of No. 59 issue.
No. 59 issue introduces 2019 JSSC
commendations for outstanding achievement in steel construction and thesis. In
addition, this issue features reports of the
12th Pacific Structural Steel Conference(PSSC) held on November 9 to 11 in Tokyo. It followed the last PSSC in 2016
in China and this time was organized by
JSSC. As reported inside, it was very
successful with more than 300 participants from 21 countries. JSSC also organized two other international activities in 2019. Those are the Tall Building
Forum of the Council on Tall Buildingand Urban Habitat held in Nara, JapanSTEEL 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
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

in July, and the 2nd IABSE Young Engineers Colloquium in East Asia held inTokyo in November. In particular, theYoung Engineers Colloquium organized
not only technical presentations but also bridge design competition for the firsttime. Construction reports of a new commercial complex “268 Orchard Road”
in Singapore and flood gate seismic reinforcement using duplex stainless steel
are also included.
Finally, we would like everyone tocontinuously understand for activities
of JSSC and we would also like to hear
your opinions at any time. ￭© 2020 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): Kazuhito TsujimotoP 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.