No. 34
November

2011

A Joint Publication of The Japan Iron and Steel Federation and Japanese Society of Steel Construction

Special Issue

Advanced Large-span Construction

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

Steel: The Leading Player for Enhanced
Large-span Hybrid Structures
By M
 amoru Kawaguchi
Prof. Emeritus, Hosei University;
Representative of KAWAGUCHI & ENGINEERS

Steel is very often utilized as the leading
element of many composite or hybrid
structures. It plays an important role as thetensile member to constitute a rational
structure of intended specific nature in collaboration with other constituent materials
which take parts of compressive, shearing
or bending members. It may be interesting
to note that the latter members can be composed by materials of various kinds, according to the purposes of design. This article describes some of the author’s recent
design works in which a variety of materi-als such as concrete, natural stone, timber,aluminum, and even air have been adopted
to constitute rational and esthetic largespan structures together with steel as theleading tensile material.

Cable- Steel Hybrid Structure:Semi-rigid Tension Structure(Yoyogi Stadium)
Yoyogi Stadium consists of two major facilities– the first and second gymnasiums.
The roofs of both gymnasiums were designed on the principle of tension structures. (See Photo 1)
The first gymnasium originally designed for swimming and ice-skating
has a seating capacity of 15,000. In thisbuilding, a similar
structural system tosuspension bridges
was adopted for its
centralstructure.
Two main cables
span 126 m between
Photo 1 First gymnasium of Yoyogi Stadium
the two principal
columns and 65 m
Fig. 1	Structural System of Yoyogi Stadiumoutside them in the
Hanging members
Main cables
backstay. A series ofBracing cables
hanging members
Columncomposed of steel
sections span the
Poolarea between themain cables and theAnchorage
curved RC boundarStruties surrounding the
1 Steel Construction Today & Tomorrow November 2011

Mamoru Kawaguchi: Former President ofInt. Assoc. for Shell & Spatial Structures;
Graduation from Fukui University in 1955
and Dr.Eng. Degree from Tokyo University
in 1966; Involved in structural designs ofTokyo Olympic Swimming Hall, Singapore
Insoor Stadium, Barcelona Olympic Sports
Palace, etc.; IABSE International Award in1995 and IASS Torroja Medal in 2001

seats. Penetrating these steel members, agroup of bracing cables run along the geodesic lines of the roof surface, which are
tensioned to increase the rigidity of thewhole roof structure. Initially ropes were
proposed to constitute the cable network toform the roof surface, but it was foreseenin the design stage that the roof surface defined by the boundary structures of different characters would not be realized bypure cable nets without largely losing
economy. To solve this problem we developed a “semi-rigid” hanging system for theroof which was constituted by tensile members with some bending rigidity and bracing cables. (Refer to Fig. 1)
Steel-RC Articulated Hybrid Structure (Tochigi Green Stadium)
Tochigi Green Stadium (Photo 2) was built
in 1993 in Utsunomiya City for soccer
games. In structural design of this structure, the following attempts have been pursued: 1) Articulation of the structural components, and 2) Prefabricated RC grandstandstructures.
The former has been considered important to realize the atmosphere of “floatingroofs in a copse” which has been the visual

Photo 2 Floating roof of Tochigi Green StadiumHybrid Structures

Steel-Natural Stone Hybrid Bridge(Inachus Bridge)
The Inachus Bridge (Photo 3) was constructed in 1994 in the City of Beppu, Kyushu, as a footbridge leading to a scenicpark named Minami-Tateishi Koen. The
span to be bridged was 34 m. In the processof discussions with the mayor and the staffof the construction division of the city, theauthor noticed that Beppu had a sister city
in China named Yantai which exported
granite stone of excellent quality. Laboratory tests proved that the stone was superbly strong and stiff for structural use, and theauthor decided to adopt the Yantai granite

Photo 3 Granite Inachus Bridge

Steel-Timber Composite Structures● Steel-Reinforced Timber Structures
Timber is an excellent natural material
which can be recycled in the forest. It isalso a material that can be felt friendly
when exposed to the space of human activity. On the other hand, timber has suchdrawbacks that it hasoften very limited
strength and rigidity
as a structural member. This situation
leads to the idea ofreinforcing timber
members with muchstronger materials
like steel. A few
bridges have alreadyPhoto 5 Aira Gymnasium

Platform

7,900

Fig. 2 Hyuga-shi Station

Skylight

Skylight
8,250

for the structuralcomponent of thebridge. The bridge
was designed to havea lenticular shapewith an arched granite upper chord and asuspended
lower
chord. In the present
design, the granite
upper chord plays a Photo 4 Onishi Hall
dual role of a principal structural member and a deck floor onwhich people directly step when they crossthe bridge.
Thus the upper chord consists of 78
blocks of granite 40 cm wide and 25 cm
deep with a varying length from 2.6 m to
3.6 m. The whole upper chord is prestressed to produce a literally “monolithic”
structural member. The lower chord consists of steel plates arranged into a chain.
The upper and lower chords are connectedto each other by means of web members
consisting of steel tubes arranged to form
inverted pyramids in a manner which theauthor calls an “open-web truss,” in which
the web of a girder is not “closed” by a repetition of lattice members as in a normal
truss. Taking into account the savings inlattice members and connecting details andesthetic advantage of a simpler appearance, the author believes that the open-web
truss has a good raison d’être in structuraldesign. The bridge was named “INACHUS(the name of the God for River in the Greekmyth) after its completion through a naming competition among the citizens of Beppu.

16,150desire of the architect about the grandstandroofs. For this purpose the supporting
structures of the roofs have been articulated into pure tensile and compressive members which have been connected to eachother by means of hinges. The articulation
makes the cross sections of the structuralcomponents smaller, and they are madeless expressive of themselves, to achieve
the feeling of “floating roofs.” The tensile
members are designed with steel rods of
32~ 52 mm in diameters, and the compressive members with prestressed concrete
piles. This may be the first example inwhich concrete piles have been used for architectural components without any further
finishing. Concrete piles are mass-produced industrial goods of high standard
both in dimensional accuracy and material
quality. Moreover, surface of concrete
piles, prestressed or non- prestressed, is sodense, fine and smooth that we can use
them as architectural members without further treatment.
Thus the grandstand and its roofs areconstituted by 25 columns of prestressed
piles and prefabricated concrete girders
which carry the floor panels on them. In thelongitudinal direction, the structure is stabilized by means of steel rod bracings, theadjacent columns standing “hand in hand”
with each other.

Canopy17,200Main stationbuilding

11,350Canopybeen built on the basis of this idea. The author was recently involved in design of anassembly hall for Onishi Town in which thearchitect wanted to have a roof supported
by a very thin series of timber beams, andhe applied steel reinforcement to these timber beams to achieve this requirement in areasonable way (Photo 4).
● Steel-Timber Hybrid Structures
Timber as material is equally strong in tension as in compression, but it is much lessefficient to join them in tension than incompression. Therefore, a hybrid design inwhich timber is located to take compression may lead to a good result.
Aira Gymnasium (Photo 5) has a plan of
100 m × 50 m, and its arena is covered bya hybrid timber shell which consists of alaminated curved surface of 200 mm inthickness and steel lattice systems. The
timber shell acts typically as a compression
member, and serves not only as a structuralelement, but as sound and heat insulationand ceiling of friendly texture.
Hyuga-shi Station (Fig. 2) has a steeltimber hybrid roof structure in a more complex form to cover a plan of 18 m × 110 m
of its rails and platform. Laminated timber
beams are fabricated in a shape which efNovember 2011 Steel Construction Today & Tomorrow 2

Hybrid Structures

Photo 6 Kochi Station

es. The hybrid arches rest on the RC supports along the north side of the building,while they are supported by the elevatedrailway structures on the south side.

Photo 7 Prestressed aluminum bridge

Photo 8 Steel membrane air dome

ficiently resists the bending moment due tothe horizontal wind loads in collaboration
with steel tube members.
The vaulted main roof of Kochi Station(Photo 6) which covers a plan of 39 m × 60
m is constituted by a group of steel-timberhybrid arches in an asymmetric shape having steel knees toward the end of the arch3 Steel Construction Today & Tomorrow November 2011

Prestressed Aluminum Bridge
A small indoor footbridge connecting a restaurant and an elevator hall was designed
in a building in Ginza (Photo 7). It is an aluminum bridge, 6 m long and 1.7 m wide.
Aluminum was chosen for its favorable visual texture, no rust, and maintenance-freenature. The whole bridge was cast in thefoundry as one block. Since nobody wasconfident about the reliability of cast aluminum alloy in terms of ductility in tension, a prestress of 300 kN was introducedby means of two prestressing rods, arranged inside the box section of the bridge
to avoid tensile stresses in the bridge.
Steel Membrane-Air Hybrid Structures
In the preceding discussion, steel has been
exclusively used for tension members,
whereas for compressive members suchvarying materials as concrete, stone, timber, and aluminum have been utilized. Oneof the most interesting materials that cantake only compression may be air. Air cannot resist big tension or shear, but it shows
great resistance against volume change. In
normal sense, air does not “collapse” or“fracture” in compression. Thus there
comes an idea that hybrid structures may
be possible using steel for tension and air
for compression. The first example realizedon the basis of this idea was the stainlesssteel membrane air-supported roof for the
sports complex at Dalhousie University of
Halifax, Canada, completed in 1979. This
roof covers an area of some 92 m × 73 m ofthe sports hall. The roof is very flat, and themembrane consists of welded stainlesssteel sheet 1.6 mm thick.
The author developed an air-supported
steel membrane system that could be applied not only to flat but also deep domical
profiles. This system which may be referred to as strip (or band or ribbon) systemutilizes the strength of metal strips mainlyin their longitudinal directions. The strips
are longitudinally continuous, and are connected firmly at their ends to the boundaries so as to fully develop their strength in
the longitudinal direction, but the adjacentstrips are not connected or only secondarily
connected to each other along their longitudinal sides. (Refer to Photo 8)
The theoretical existence of a domical
surface that develops no hoop stresses under internal air pressure has been known asa configuration corresponding to an extreme condition of rotational membraneshells subject to internal uniform loads.
The author named that surface “the shallowest possible pneumatic form,” and applied it to steel membrane air domes.
A test dome having a plan of 20 m in diameter was constructed on the above principle using a stainless steel skin of 0.3 mm
in thickness. The shape survey of the dome
proved that it was sufficiently close to thetheoretical one. The dome has experienced
a few strong winds including one which
blew at a speed of 30 m/sec without any
problem.
Conclusive Remarks
Steel is a superb material. It is strong bothin tension and compression, showing great
rigidity too. It develops its utmost strength
especially when it is utilized in tension,
whereas its compressive strength largely
depends on the way it is applied, causing
often much reduction due to buckling.
Therefore when we think of developing a
new structural component or structural system by combining more than two materials, one of them for tensile strength is almost always steel. But there are manykinds of materials that take the part of resisting compression and/or shear. In thepresent article, the author tried to show thevariety of materials that can be used for
those tasks in combination with steel thatalways plays the role of tensile members.
The materials shown in the present article
have been concrete, natural stone, timber,aluminum, and even air. There are of course
many more materials with which steel can
produce new structural components andstructural systems.

SkyPark

SkyPark— A Huge Rooftop, Steel Structure Spanning Three High-rise
Towers —By Yasuhisa Miwa
Project Manager, Steel Structure Engineering Dept., JFE Engineering Corporation
Outline of SkyPark
As its name implies, SkyPark is an aerialpark constructed atop three high-rise towers in Singapore (Photo 1). It measures 340
m in total length and 40 m in width. As a
new landmark, SkyPark celebrated its
grand opening in June 2010 and now stands
out among the various facilities operatedby Marine Bay Sands Pte Ltd., an integrated resort company in Singapore.
A joint venture between JFE Engineering Corporation of Japan and Yongnam Engineering & Construction Pte Ltd. of Singapore was awarded the contract in April
2008 to construct the steelwork for SkyPark. The joint venture immediately commenced a detailed design and erection planand in July 2009 started the on-site work tocomplete the erection of an 8,000-ton steel
structure in a mere nine months.
Structure of SkyPark
SkyPark is composed of two steel truss
bridges connecting the three hotel towers(Towers 1, 2 and 3), a steel box girder
bridge with a cantilevered structure on
Tower 3, and two steel-frame structures
atop Towers 1 and 2 (Photo 2) to make an
integrated structure. It is designed as an enclosed structure to support the cladding
with purlins.
For the bridges connecting the three
towers, steel truss bridges were adopted as
an alternative to the original design thatthree main girders are connected by thecross framing transversal beams. Conforming to the curved alignment of SkyPark and the configuration of the towers that
support the bridge structures, the trusses
have a non-parallel configuration and withchanging truss heights as imposed by theaesthetic restriction, thereby presenting thecomplicated structure seen in Fig. 1.
The structure on Tower 3 is composed© Marina Bay Sands Pte Ltd.

Photo 1 Full view of SkyPark© Marina Bay Sands Pte Ltd.

Steelbox girder
bridgeSteeltruss
bridgeTower 3Steelstructurebuilding

Tower 2

Steel
truss
bridgeSteelstructurebuilding

Tower 1

Photo 2 Overall structures of SkyPark
November 2011 Steel Construction Today & Tomorrow 4

Fig. 1 Section of Steel Truss Bridge

Fig. 2 Steel Box Girder Bridge

Span lenth 51 m

Strand cable

A

Max. height 10 m

Tower 3
Rigid

Bearing
position

Elevation

Tower top 54.6 m

Section A-A

A

Bearing
HTL67
Cantilever 67.7 m

38 m

A

12 m

Section A-A

Cross Sectionof three main girders, with the two on thesides changing from I-section plate girders
to box girders in their configuration and extending to form a 67.7 m-long cantilevered
structure. The main girders are supportedby W-shaped circular hollow columns installed on the RC diaphragm wall of the
55th story, the topmost floor of Tower 3.
The main girder on the W Column at grid
HTL60 and HTL67 is supported by fixedbearings, and the other points are rigidly
connected by weld joining. In order to support the cantilevered structure, a PC strand
is placed at the upper flange inside the box
girder to be tensioned upon completion of
installation of box girders. (Fig. 2). Other
special structural approaches are also adopted, such as installation of a tuned massdamper weighing 5 tons at the top end of
the cantilevered structure.
Design of SkyPark
While SkyPark is an architectural structure, it has the performance characteristics
of a bridge. Accordingly, the design wasmade in conformity with two standards—

BS5950: 2000 Structural
Use of Steelworks in Buildings (a British Standard forthe design, fabrication anderection of structural steelwork) and BS5400: 1988
Steel, Concrete and Composite Bridges (a British
Standard for design andconstruction of steel, concrete and composite bridges). For the structural materials, S355J of BS EN 10025
Hot Rolled Products of Structural Steels
was applied. As for the design of segment
joints, the friction grip design was madeconforming to the code “Non-slip in service” of BS 5950. Specifically, the code allows friction surface slippage at the time ofultimate loading and resists the ultimate
load by means of the shear resistance of thebolts and the bearing capacity of the steel
plates. Torque shear-type bolts (S10T)
were adopted.
In the design of the bearings, Maurer
Sohne GmbH & Co. of Germany was ap-

20 m

9m

A

Steel circular pierTower 3pointed to promote cooperative design.
BS5400 Part 3, 1983 was adopted as thedesign standard.
Because 1.5-hour fireproof performance
was required for the area within 10 m of the
top of the tower and for the tower exterior,
expansive intumescent paint was applied tothe section in which the structures are exposed, and sprayed vermiculite was applied to the section covered with exterior
finish cladding and other members.

© Marina Bay Sands Pte Ltd.

© Marina Bay Sands Pte Ltd.

Photo 3 Steelwork fabrication at Yongnam E&C
5 Steel Construction Today & Tomorrow November 2011

Photo 4 Trial assembly at Yongnam E&C

SkyPark
Table 1 Heavy Lifting Record
Heavy lifting
Steel truss bridge 1

Steel Truss Bridge 2
Steel box girder on
Tower 3

Steel box girder at
north cantilever

Segment Date of liftingNo.
(2009)
A3
1-Oct
A2
18-OctA1
29-OctA6
16-Nov
A5
24-Nov
A4
6-Dec
West
12-OctEast
12-Oct
NC1
1-Dec
NC2
9-Dec
NC3
14-DecNC418-DecNC523-DecNC629-DecSegment
weight (tons)
386
417
324
333
319
255
746
786
176
195
182
129
99
70

Segment
length (m)
56.8
54.7
52.3
54.0
51.9
49.4
73.6
75.7
5.9
7.2
8.6
8.4
8.4
7.5

Reference
Photos 5 and 6

Fig. 3 Heavy Lifting Procedure
Step-1
Lifting
200 m

Gantry frame

Strand jack
SLU220 ton

Strands
ASTM A 416M
22nos. of 0.6” 7wire strand

Tower 1
Tower 2Assembled on groundStep-2Sliding
40 m

Sliding beamincorporating
strand jackSliding to
final position

Photo 7
Photo 8

Steelwork Fabrication and Erection
Steel structural members were fabricatedby Yongnam Engineering & Construction,a local fabricator, and transported to theconstruction site (Photos 3 and 4).
In erecting the steel-frame structures on
Towers 1 and 2, the structural members
were lifted one by one using the tower
crane to place them at the specified positions. Structural members for the box girder bridge on Tower 3, the two tower-connecting bridges and the cantilevered
structure on Tower 3 were pre-assembled
into large segments at the ground level inthe side of the tower and lifted by strand
jack. The large segments thus assembled
numbered 3 each for the main girders of thetwo tower-connecting bridges, 2 for thetwo main girders of the box girder on Tower 3, and 6 for cantilevered structure. A total of 14 large segments, weighing 4,000
tons in total, were lifted and erected during
the three months from October 1, 2009 to
December 29, 2009 (Table 1).
The erection work was undertaken bymeans of a heavy-duty strand jack assembled on a gantry frame installed atop thetower. The segments were lifted to the target height of 200 m. Each segment was lifted at a rate of 15 m/hour, nearly the maximum speed of the jack stroke movement,over a 15-hour period. After each segment
was lifted, it was slid into the specified position using a horizontal-pulling jack andwas then lowered to its final position by releasing the jack’s hydraulic pressure. (SeeFig. 3, Photos 5~8)
When planning the lifting work, the assembly position and lift point were decided
in a manner that would secure a 1 m-wide
gap that would prevent the lifted segmentsfrom making contact with the hotel tower
during lifting, even if the segment’s girderwere to move laterally due to wind pressure
resulting from the maximum 26 m/second
wind velocity assumed in the design.
Safety Measures
Because the construction work for SkyPark
routinely took place at heights surpassing
200 m as well as ground with other trades,
unprecedented care was taken to securemaximum worker safety. Practically speaking, utmost efforts were thoroughly and repeatedly made to spread over a large working group, including 450 workers and 70
staff during the busiest period, that all
workers and staff wear a full harness to prevent falling and carry lanyards to prevent
November 2011 Steel Construction Today & Tomorrow 6

SkyPark© Marina Bay Sands Pte Ltd.

© Marina Bay Sands Pte Ltd.

Photo 6 Sliding of steel truss bridge segment into the specified position© Marina Bay Sands Pte Ltd.
HTL67
4nos.SLU330 tons
Heavy lifting gantry frame
HTL62
4nos.SLU120 tons

Photo 5	Heavy lifting of steel truss bridge segment

the dropping of tools.
A detailed procedural manual detailingevery type of work was prepared and reviewed by qualified safety officers. The
manual not only obtained approval fromboth the project owner and the consultants
but was also examined by every associatedmanager. And, following thorough discussions, every staff member was well acquainted with the manual. In particular,
painstaking risk management control was
exerted over work that was forecasted to be
dangerous.
Highest Safety Measures Secured
for Difficult WorkA noteworthy accomplishment in the construction of SkyPark is the completion ofsuch a huge project, involving difficult
construction work, without serious accidents over one million of working hours oflabor. This is largely attributable to theunited and highly vigorous effort by local
enterprise staff, locally recruited engineers
and the Japanese staff, efforts that transcended culture and language, to successfully complete the project. Also noteworthy is the presentation to the SkyPark
project of the Structural Steel DesignAwards 2010 by the Structural Steel Society of Singapore.
7 Steel Construction Today & Tomorrow November 2011

Steel box girder segment
Eest / 76 m * 746 tons
Steel box girder segment
West / 74 m * 786 tons

Tower 3

Photo 7 Heavy lifting of box girder bridge segment at Tower 3© Marina Bay Sands Pte Ltd.
Heavy lifting gantry frame
4nos.SLU70 tons

Steel box girder

Steel box girder segment
NC1 / 5.9 m * 176 tons

Photo 8 Heavy lifting of cantilever Structure on Tower 3

Tower 3

Osaka Station

Osaka Station— Large-scale Domed Roof Installed above
Station Platform —By Takayuki Umeki
Senior Manager, Construction Department, West Japan Railway Company
The “Osaka Station Development Project”
was a seven-year undertaking that began in
May 2004 and finally culminated on May
4, 2011 with the opening “Osaka Station
City.” The new complex consists of thepreviously existing station facilities, theNorth Gate Building located on the northside of the station, the South Gate Buildingon the south side, the new terminal area on
the bridge that connects the two buildings,
and a domed roof.
Outline of New Osaka Station City
The area on the north side of Osaka Station,
including the Umeda freight terminal, isranked as the best remaining urban commercial district in Japan and is expected todevelop as a new base that will lead the revival of the Kansai area. In October 2003,
Osaka City published a document titled“Comprehensive Plan for Osaka Station
North District” that indicates the basic direction of urban development in Osakaprove and reinforce access to Osaka Station from other urban transport networks.

City (Fig. 1).
Osaka Station City is positioned as alink in town building in the area north of
Osaka Station and has been aggressively
promoted by the Osaka City governmentand other administrative organizations, aswell as a variety of private enterprises andtenants in the surrounding area.
Specifically, the project’s primary emphasis is to improve pedestrian networks
with neighboring districts, to enhance thegrowth of bustling community functions
suitable for a gateway district to the Osakaand Kansai areas, and to improve the attractiveness of the area in conjunction withother railway companies. The eventual aim
is to dramatically enhance the area’s function as a core component of Osaka Stationand the surrounding area, in combination
with positive efforts by West Japan Railway Company to, among other things, extend operations of the Kyushu and Sanyo
Shin­kansen super-express lines and to im-

Basic Goals of the Osaka Station
City Project
The project was promoted based on the following four goals.
● Provision of Plazas and Passageways
The new south-north connecting passageway was created in the space above therailway tracks to secure smooth moving
lines and to improve the ease for the visitors to get around within Osaka Station andits peripheral areas. Further, eight plazas
were installed within the station to provide
bustling and relaxing places. (Photo 1)● Improvement of Station Convenience
Various approaches to improving the convenience of the station were devised—in-

Fig. 1 Comprehensive Plan for Osaka City North District
Land utilization zoning

Comprehensive Plan for Osaka City North District

South-North (Symbol) Axis

Basic plan area (about 24 ha)

Creation of an affluent and distinctive space rich inwater and greenery through the integrated improvementof wide walkway spaces, site space and structures

Relaxation Zone

Quiet urban housing and medical treatment
facilities surrounded by greenery

First-stage Development Area
(East Area, about 7 ha)

Affluent Zone

Formation of affluent space; Hotels,
offices and housing
Enlargement of knowledge and capital functions(including culture and art); University and graduate
school satellites

Knowledge/Capital Zone (1)Nurturing of new industries and businesses;
Research/development/scientific functions, offices

A

sta

tio

n

pla

n

Active East-West Axis

w
Ne

i

ng
ldi

g

Pa

in
rk

bu

ing

ild

Bu

on

n

e
a
ak artm
Os ep )rt
TY u D eda
No
AC imar (UmDa toreSnotiecd s sakaeglar Y OEn ACT
of

te

a
hG

a

ak

Expansion Zone

International business base, nucleus for wide-areadisaster prevention and administration; Culture,entertainment, media

Formation of highly distinctive streets;
High-end hotels and housing

B

West Area
Creation of an area with trees and sunbeams streaming
through leaves that is integrated with commercial
facilities; formation of active, main moving axis

Sophistication Zone

C

Knowledge/Capital Zone (2)

Os

ti
Sta

Next-generation Robotics R&D Base
Exchange Zone

Formation of active base for interpersonal
exchange; Commercial facilities and offices

Station Plaza Zone

Formation of symbolic space rich in amenities
as a gateway to Osaka

Source: Basic Plan for Town Building at Osaka Station North Area (Osaka City)
November 2011 Steel Construction Today & Tomorrow 8

Photo 1 Improved station square and passage

Photo 3 Newly-built North Gate Building

stallation of the ticketing floor on the connecting bridge at the station center,
improvement of the concourse within theticket gate area and provision of totally barrier-free facilities. In addition, a large-scale
domed roof that runs about 180 m north towest and about 100 m south to north was
installed above the platforms. (Photo 2)● Installation of New North Gate
Building
In order to provide a gateway to the area
north of Osaka Station, a new building wasconstructed on the north side of the stationthat houses a diversity of urban functions,such as a department store, specialty stores,
restaurants, service functions and offices.
The building not only offers station functions but also provides plazas and otherspaces where people can interact. (Photo 3)●E nlargement of South Gate Building (Formerly ACTY Osaka Building)In parallel with improvements to the station plazas, the existing South Gate Building that serves as an entrance to the area
south of Osaka Station was enlarged. Work
was also completed to improve moving
lines and to improve the ease for the visi9 Steel Construction Today & Tomorrow November 2011

finished using folded
plates and is equippedwith 12 rows of skylights to brighten theinterior space under
the dome.
In order to effectively mitigate seismic forces that mightwork on the domed
roof, which has a total
weight of 3,500 tons,a base-isolation strucPhoto 2	Large-scale domed roof on the station building
ture was adopted. A
on the passageway bridge
total of 17 laminatedrubber isolators andlaminated-rubber integrated base isolation U-shaped dampers were installed on
the supporting sectionof the North Gate
Building. Further, 17cross slide bearings(range of motion: 1m) and 6 oil dampers
were installed on the
supporting section of
Photo 4 Enlarged South Gate Building
the north-west truss
tors to get around to the peripheral areas. framing so as to avoid transmitting exces(Photo 4)
sive horizontal force to the lower structureduring an earthquake. (Refer to Fig. 2)
Design of Domed RoofFor the roof finishing material, a heavyServing as a symbolic structure in the Osa- duty coating of silicon denatured epoxy
ka Station City project, a large-scale domed resin was adopted. This coating has a reroof about 180 m in the north-west direc- cord of wider usage in bridge construction
tion and about 100 m in the south-north di- and features a low frequency of mainterection was installed above the platforms nance.
of Osaka Station. A comfortable, attractive
Meanwhile, in order to reduce water usstation space was thus produced that uni- age, the rainwater that flows off the roof isfies the North and South Gate Buildings, collected, via the east-south and norththe station building on the passageway south trusses, in a storage tank located on
bridge, and the station platforms (Photo 5). the basement level of the North Gate BuildThe domed roof is supported at the 12th ing and is used as rinse water for toilets.
story of the North Gate
Building and by truss framing (east-north framing)
OSAKA STATION CITY
that spans the platform. The
South Gate Building
North Gate Building
basic component of theframe is a triangular-shaped
space pipe truss (total
Domed roof
length: 100 m; 600 in max.
dia.), 17 rows of which
comprise the domed roof—
which is installed in a diagNorth-south
East-west
onal form with a maximum
framingframing
inclination angle of 23° anda maximum difference in elevation of 30 m. The roof is
Photo 5 Domed roof

Osaka Station
Fig. 2 Outline of Seismic-isolation Devices for Domed Roof Structure Installed on Platforms

Laminated rubber isolator

Laminated-rubber integrated baseisolation U-shaped damper

12th floor of North Gate Building

North Gate Building

South-northframing
East-west
framing
Cross sliding bearing

3600

Main member:
H–244×175×7×11

Range of motion 1006 mm

Pressurechamber ①

Diagonal member
165.2⌀×7.1~12.7

Minimum
angle 43.60˚

Lower chord
558.8⌀×16.0~22.0

Check valve
Pressurechamber ②
Suctionvalve

Relief valve

Pressure
regulator

Range of motion 1006 mm

Tank (oil reservoir + air cell)

Upper chord
406.4⌀×12.0~19.0

Maximum height 4500
(Minimum height 2500)

Oil damper

Rod

PistonOilreservoir

Construction of Domed Roof
In constructing the domed roof, it was necessary to implement the work while allowing the station to function normally. Accordingly, depending on the type of work
and in consideration of train operations andpassenger safety, construction was executed for about three hours from the departureof the last late-night train until the arrivalof the first early morning train. Under thesesevere restrictions, an effective approach

was adopted in which both the framing of
the triangular-shaped space pipe trusses
and the finishing work were completed
one-by-one on the top station building’s
roof, which had been installed in advanceon the passageway bridge, and from which
the completed members were slid to boththe east and west sides by 7 times to eachside. As a result, the domed roof was completed without any serious accidents. The
adopted method is introduced in the fol-lowing.
At first, ground assembly of the trusses
was undertaken utilizing the rooftop of
North Gate Building lower-floor sectionthat was simultaneously constructed. The
trusses were divided into eight structuralmembers, which were ground-assembled.
Subsequently, the trusses were moved tothe station building on the passageway
bridge where they were joined.
As a workspace for joining the moved

November 2011 Steel Construction Today & Tomorrow 10

Osaka Station
trusses, a bent gantry was installed on the rooftops ofSouth-northboth the east and west ends
sectionof the station building on thepassageway bridge, which
Dome truss
assembly
was built prior to the con200–ton crawler
struction of the center seccraneP1FLtion of the station building.
13FL⑧
On the bent gantry, the eight
M13FL
⑦
12FL
⑥
divided truss members were⑤
11FL
joined together; and, at the
④
10FL
③
9FL
same time, the folded plates,
Bent gantry
8FL② ①
top glass, coating and other
7FL
6FL
finishing work were comEast-west
5FL
framing
pleted. At this stage, quality
4FL
新北ビル
Station building on
3FL
passageway bridge
inspection by means of pal2FL
pation was conducted. (Fig.
1FL
3)
Moving line for sending-in/out material and machinery
Next, each of the comSouth Gate Building
North Gate Building
pleted truss frames was slid
to the east and west sides by
Fig. 4	Sliding Work for Domed Roof Trusses on the Rooftop of Station Building on Passage7 times while occasionallyway Bridge
adding another truss (Fig. 4).
200-ton crawler
East-west
crane
The domed roof trusses
sectionwere moved to their prescribed position atop the railway by running a truss-loadSliding
Slidinged transport equipment
Bent gantry(TIRTANK; max. 200 tons)
7FL
on a rail girder placed on the
5FL
12th floor of the North Gate
South-northSouth-north3FL
framingframing
Building and on a beam of2FL
Plan
the east-south framing (PhoMoving line for sending-in/
7-time sliding to east side
7-time sliding to west sideout material and machineryto 6). For the sliding jack, acontinuously operable, cenStation building on
No. 4 platform
ter hole-type, high-speed
passageway bridge
jack (double twin jack; max.
70 tons) was used to comNo. 3 platform
plete each sliding job within
Sliding
Sliding
the short period between the
Assembly
No. 2 platform
yard
departure of the last train andthe arrival of the first train.
No. 1 platform
Meanwhile, in order to understand on a real-time basis
the displacement and instalLoop-line platform
lation conditions of the trussEast-west framing
es during sliding, a measurement control system wasdeveloped to improve work safety.
Domed roof truss
Lastly, employing the bent gantry located on the rooftop of the station building
over the passageway bridge, the joining
and finishing work were conducted on thethree trusses (of 17 total trusses) that were
not subject to sliding. Then, the center section of the domed roof structure was built
Transport equipment(TIRTANK)
to complete the entire domed roof.

Fig. 3 Assembly of Domed Roof Trusses on the Rooftop of Station Building on Passageway Bridge

Double-twin jack

Rail girder

Photo 6 Double twin jack used for truss sliding and TIRTANK used for truss movement
11 Steel Construction Today & Tomorrow November 2011

Asahikawa Railway Station

Asahikawa Railway Station— Structural Design of Open Large-span Station Building —By M amoru Kawaguchi and Yushi Aso
KAWAGUCHI & ENGINEERS
Started 15 years ago in 1995, the first phaseof construction work on the JR Asahikawa
station building, including an elevated railway structure, was completed in October2010. The station is slated to celebrate its
grand opening in November 2011. (SeePhotos 1 and 2, Fig. 1)
Structural Outline
The building shed of Asahikawa Railway
Station is a steel-frame structure built upona reinforced concrete (RC) elevated railway structure. The shed has a total lengthof about 180 m, a width of about 60 m anda maximum height of 26.3 m (Fig. 2).
Because the station is located in Asahikawa City, Hokkaido, a prominent areaof heavy snowfall in Japan, the treatmentof heavy snow accumulation is a wellknown and serious problem. In addition,
because the plan calls for the efficient utilization of geographical conditions adja-

cent to rivers in the surrounding area, theroof of Asahikawa Station was planned to
be of the snow-retaining type.

Generally, in the construction of stationbuilding sheds in Hokkaido, one of the primary requisites is the use of concrete slabs

Photo 1 Full view of Asahikawa Station

Fig. 2 Structural Outline of Asahikawa Station
178165122500

27083

57063

28683

Expansion joint

Expansion joint

Photo 2 Inner view of Asahikawa Station

9180 12500

Fig. 1	Executed Structural Design(Section)

November 2011 Steel Construction Today & Tomorrow 12

specifically, the roof
framing consists of upper and lower chords ofH250 × 250 and of steel
tubes (165.2~216.3 mm
in dia.) that constitutethe frame’s diagonal
members and struts(Photo 3). The roof was
designed to secure horizontal rigidity by theuse of RC slabs (thickness: 150 mm). The
building exterior is supported by H-shape pincolumns (H400 × 200)that also serve as mul-design of Asahikawa Station, they abide by
the design condition that “the bending
stress not change according to the loading
condition at the shed column base.” This
problem was solved by adopting cast steel
pin bearings for the base of the fourbranched columns of the shed.
Further, taking into account the temperature-affected load, expansion joints (attwo locations) were provided in the area ofthe elevated railway structure beneath theshed. The expansion joints do not allow thestress transfer in the direction of the railway but do allow stress transfer in other directions. (See Fig. 3) Expansion joints having a similar function were also provided in
the area of the shed under which the railway runs.

Structural Design of Station Building
In designing the station building, collaboration was required between the civil engineers who designed the elevated railway
structure and the structural engineers who
designed the shed.
However, in terms of the sequential order of events, completion of the structuraldesign of the elevated railway structure andcommencement of the corresponding
structural work had to occur prior to thestart of the design work on the shed.
This led to a difficulty related to thestructural design of the station building.
Namely, information about the shed column base reaction force was required forthe design of the elevated railway structure
and this information had to be supplied tothe civil engineers as early as possible inthe design stage. In addition, the simpler
the load from the shed column base, thebetter it was for the structural designers of
the elevated railway structure. For that purpose, the civil engineers requested of thestructural engineers that, in the structural

Detail Designs● Four-branched Columns
Fig. 4 and Photo 4 show a four-branchedcolumn. The main structural members usedat the four corners are steel tubes (404.6

Photo 3 Roof framing

not only to handle the large snow loads thatnaturally accumulate during Hokkaido’s
winters but also to prevent water leakage.
As a result, the framing that supports a station shed’s roof must bear large loads andresist seismic forces over sustained periodsof time. To this end, comparatively shortcolumns with large diameters are locatedtogether in large numbers in most railway
station buildings in Hokkaido with the result that the platforms tend to be dark spaces with limited visibility. In order to realize
platforms with fewer obstacles at Asahikawa Station, a structural plan was worked
out that secures minimal use of platformcolumns and greater ceiling height.
To meet the requirements of this structural plan, it was necessary to ensure highstrength and rigidity for the roof framing
and the underlying support columns, whichthen led to the adoption of steel-frame
trusses with sufficient beam depth andbuilt-up columns called four-branched tubular steel columns.
The shed roof frame is a parallel chordtruss structure that is supported by 20 fourbranched columns and has a beam depth of
3 m in both the X and Y directions. Morelions.

Fig. 4	Four-branched Tubular Steel
ColumnCast steel joint

Cast steel
pin bearing

Fig. 3 Stress Transfer of Expansion Joint
Elevated railway structure
Horizontal shear force
R12

Horizontal shear force
R13

R14

Shed structure
R12

R13

Vertical shear force
13 Steel Construction Today & Tomorrow November 2011

R14

Vertical shear force

Photo 4	Completed four-branched tubular steel
columnAsahikawa Railway Station

1370

Fig. 5 Cast steel pin bearing

A

A

1370

A-A view

50 250

80

50

160

⌀810

⌀76

Photo 5 Cast steel pin bearing

dia. × 30 for the lower structure and 404.6
dia. × 16 for the upper structure); the auxiliary members are steel tubes (216.3 dia. ×25); and the intermediate horizontal joining members are also steel tubes (165.2 dia.
× 9). Fig. 5 and Photo 5 show a cast steel
pin bearing used for the column bases. The
column bases were tightly connected to theelevated railway structure with anchor
bolts (8 × M76).
● Expansion Joints
In the elevated railway structure, expansion joints were provided at two locations
that do not restrict movement in the direction of the railway as shown in Fig. 2. In theshed, too, expansion joints having similar
behavior were provided at corresponding
locations so that the joints would follow
the movement of the elevated railway
structure to avoid any adverse effect on theshed. (See Fig. 6)
In order not to restrict axial-direction
movement between trusses, a long hole
was drilled in the axial direction to connect
them using pins (65 dia.). A detail design
was adopted in which the strong-axis shear
force is transferred via the pin and theweak-axis shear force is transferred via theweak-axis shear stopper that extends fromthe truss end in a cantilever beam state.

Fig. 6 Expansion Joint Installed on Shed Roof
Strong-axis
shear stopper
C

B
Strong-axis
shear stopperA

B section

Teflon sheet

C section
Pin

A

Weak-axis
shear stopper
Enlarged drawing of pin section

A section

Teflon sheet

Weak-axis
shear stopper

Open and Bright Station Building
A significant task in the structural design
work discussed earlier was to construct, in
one of Japan’s prominent areas of heavy
snow and in a town with a long winter season, an open and bright station buildingthat would accommodate large crowds ofpeople. At the same time, another large task

was imposed from a civil engineering perspective on the structural design work—
the realization of a column base that would
suppress bending stress deviation in the elevated railway structure. We believe thatthese two tasks have been successfully hurdled by the adoption of four-branched columns and cast steel pin bearings.

November 2011 Steel Construction Today & Tomorrow 14

ION Orchard— Mega Steel Truss Structure Spanning MRT Station —By K
 azushi Yamashita (Deputy General Manager) and Kelvin Teh (Quality Manager)
Penta-Ocean Construction Co., Ltd.
Introduction, Accessibility andFacilities
Seated at the gateway to Orchard Road,ION Orchard is a mixed development featuring a retail podium and a residential
tower (Photo 1).
ION Orchard brings together the world’s
best loved brands for their flagship, concept and lifestyle stores within one development over eight levels of intelligently
designed shopping space—four levels
above ground and four levels below.
ION Orchard offers to visitors a unique
shopping experience of retail, F&B (food/beverage) and entertainment stores, which
include six of the world’s top luxury brands
with their signature flagships in duplex
units fronting Orchard Road, international
brands, and popular high street fashion andlifestyle stores carefully selected for theirstrong branding and innovative retailingconcepts. In addition to the extensive stable of brands, an extensive food hall willoffer to visitors a myriad of food choices
ranging from local favorites to international cuisine.
ION Art, a dedicated programme, introduces new and multi-media art into the integrated mall experience and offers the bestof Singapore and other Asian modern andcontemporary art and design of establishedand emerging artists and designers. This includes a 5,600 sq ft gallery space within themall—the largest of its kind in Singapore—that houses international and local
exhibitions and displays of art, design andnew media.
ION Sky, an observation deck, is an
event and F&B space. ION Sky is locatedon L55 and L56 and at an impressive 218
m, the tallest point on Orchard Road, giving visitors a commanding 360 degreeview of the city.
With more than 330 shops spread over a
net lettable area of 624,440 sq ft on eightlevels of space, including four built underground. The fifth to eighth floors are taken
up by carpark lots and M&E (mechanicaland electrical) plant rooms. (Photo 2)
Integrated with Orchard MRT Stationand connected to the surrounding developments, direct access is provided to the Orchard MRT Station below. A new underground pedestrian mall across Paterson
Road to Wheelock Place completes the underground pedestrian network at the Orchard Road-Paterson Road junction.
Orchard Residences is named for its
most coveted and strategic location at the
gateway to Orchard Road. It is also Orchard Road’s tallest landmark building, astature and distinction approved by the au-thorities. A total of limited 175 exclusive,super luxury apartments housed in the district’s tallest and most architecturally-definitive landmark aim to offer a lifestyle oftimeless elegance and privacy in the midstof the vibrant city below. Orchard Residences sets unparalleled benchmarks in every aspect of luxury living by way of its allencompassing design features thatmaximize its views and its attention to every lifestyle need of the most discerning.
Construction Challenges
The main contractor was given challenging
tasks to turn the iconic ION Orchard fromvision to reality. These challenges include:●B uilding above and beside an existing
live MRT Station (with loading constraints)●C onstructing an underpass to connect
ION Orchard to Wheelock Place below,
an existing busy road (keeping same
number of lanes during diversion at dif-

Project Outline● Name: ION Orchard● Location: 2, Orchard Turn, Singapore 238801● Construction floor area: Approximately 160,615 m2● Building height: 218 m● Usage: Retail mall and a residential tower (175 super luxury apartments)● Foundation: Barrette piles and bored pile with steel plunge in columns● Podium super-structure: Steel mega trusses, composite mega columns and composite metal
deck slab● Tower super-structure: Precast and reinforced concrete● Method of construction: Top-down construction from basement 1 level● Project status: Completed in May 2009 (retail) and Oct. 2010 (residential)● Client: A joint venture between CapitaLand and Sun Hung Kai Properties● Architects: Benoy Architects (Hong Kong) and RSP Architects Planners and Engineers Pte
Ltd (S’pore)● Main contractor: Penta-Ocean Construction Co., Ltd.
(See Photo 1)
Photo 1 Full view of ION Orchard development
15 Steel Construction Today & Tomorrow November 2011

ION Orchard
tion as the floor slabs
were designed to support the basement
walls, thus saving timeand resources.
●M ega steel trusses
spanning across andabove the MRT Station were constructed for levels 5 to 8
due to the station’s
loading constraints.
Composite
megacolumns were constructed to support
these mega trusses
which in turn were
supported by huge
Photo 2	More than 300 shops are spread over eight levels of space
including four levels underground (CG)barrette piles thatwere constructed as
the foundation and permanent basement
ferent work stages)
columns.
● The podium’s superstructure was conConstruction Strategy and Innovastructed using steel structure and comtion
posite metal decking system. DismanWith the above challenges and constraints
tling of formwork is was not required,in mind, the following construction strateand slab was constructed on metal deck,gy and innovation were employed:
which thus improved safety and reduced● Diaphragm wall was constructed as perconstruction time and environmental immanent wall for basement and underpact.
pass.
● Top-down construction method from ● The tower block was constructed on a
6-day per floor cycle using precast shear
basement 1 level was employed so thatwalls, beams and planks including presuperstructure works and basement
cast staircases. Table forms were not reworks can proceed concurrently. Thisquired, and thus internal wet trades andmethod also eliminated the need for temM&E services could proceed immediateporary steel struts for basement construc-

ly when each floor was constructed.
(Refer to Fig. 1)

ION Orchard’s Mega Truss Construction
The unique steel construction process inthis project is the mega truss construction
spanning across the MRT Station. The
stage-by-stage processes relating to thisconstruction are emphasized as follows:● Barrette pile and column construction● Mega column construction● Mega truss assembly● Heavy lifting of mega trusses● Composite metal deck slab construction(Refer to Fig. 2)
Barrette Pile and Column Construction
Barrette piles and columns were used to address the requirement for large singularpoint loads from individual mega columns
for mega trusses and for the 56 storey-highresidential tower.
A barrette pile configuration consists ofseveral barrette cages, a barrette beam toconnect these cages and the barrette column placed on top of barrette beam.
The construction method is very similar
to the diaphragm wall construction in that,upon excavation to the required depth, reinforcements were installed and then castusing tremie pipes, allowing concrete G50
to be filled from bottom up.
The width of barrette piles are generally
1.5 m with lengths from 6 m to 9 m andFig. 1 Construction Strategy and Innovation
Max. 218 m
Observation deck
55th and 56th storeys
Structural elements
RC, PT
Steel, composite
Precast, RC

Mega trusses

Existing MRT
Station9th-storey Environmental Deckand residential facilities
Existing
Wheelock Place
PatersonTop-downroadmethodBasement 1

Existing
Orchard MRT

Patersonroad

WheelockPlace

New underpass

November 2011 Steel Construction Today & Tomorrow 16

Fig. 2 Mega Truss over MRT Station

Mega trusses

Mega column

Photo 3 Mega column construction
Barrette pileFig. 3 Barrette Pile and Column Construction

Basement 1

Mega column

Column cagewith metal form
Basement 4
Barrette beam

Barrette cage

depth ranging from 43 m to 82.5 m. The
width of the barrette columns to support
mega columns is 1.5 m, and the lengths
ranging from 1.5 m to 3 m. Total lifting
weight ranged between 50 tons to 135 tons.
Concrete for each pour ranged from 430 m3
to 1,130 m3. Sonic tests were carried out toconfirm the pile integrity before excavation
to expose the barrette columns. (Refer toFig. 3)proximately 37.7 m. (Photo3)

Mega Truss Assembly
There were a total of 14
mega trusses constructedwith the longest and heaviest truss, 508.93 tons inweight and 75.63 m inlength, to span across the
MRT. The heaviest segment for this truss was approximately 60 tons with alength of 23.73 m.
Due to existing structures above the MRT, theassembling of mega trusses
could not be done at ground level. Therefore, a temporary platform with temporary
column supports (totaling 2,500 tons ofsteel) was erected at level 3 (due to con-straint for craneage requirements for thelifting of steel sections).
Five floors of steel trusses were assembled on this temporary platform, and thecompleted trusses together with its associated floor beams were checked thoroughly
before allowing the jacking up to their final
level. (Refer to Fig. 4 and Photo 4)

Photo 4	Mega truss assembly (temporary
platform)

Fig. 4 Mega Truss Assembly

Mega Column Construction
Mega columns of sizes 2 m x 2 m, 1.5 m x
2 m and 1.75 m x 2 m, and 2.4 m in diameter composite (each containing 4 universal columns of weights 162, 202, and 283kg/m) were secured to the top of barrettecolumn.
The mega columns were constructed in
3~4 segments up to the 9th storey. The
height of the tallest mega columns was ap17 Steel Construction Today & Tomorrow November 2011

Longest and Heaviest Truss
Length: 75.63 m
Weight: Approx: 508.93 T
Heaviest segment: Approx: 60 T, 23.73 m

Heaviest segment

ION Orchard
Fig. 5 Mega Truss Heavy Lifting Equipment and Process
D

Column bracings
added to increase
stiffness for jacklifting

StrandbundleUpperanchorage
PistonGrippers

MT / E14 / A5
Section A-A

H
Centrehole jackLower
anchorage
W

Heavy Lifting of Mega Trusses
A heavy lifting specialist was engaged tolift the completed mega trusses from level
3 to its final position at level 5 due to limitations by craneage facilities. This wasachieved using a hydraulic strand jacking
system.
The main components of this hydraulicjacking system are the motive unit (consisting of a hydraulic centre hole jack and thelower and upper anchorages which is attached to the jack piston), the tensile member (consisting of 7 wire pre-stressing steel
strands with 15 mm in nominal diameter)with the anchorage for the load, the hydraulic pump and its controls.
During lifting, the jack was extended,causing the individual strands of the tensile

Before lift

member to be gripped by the upper anchorage and thus to be moved upwards. At thestart of the piston’s downward movement,
the strands were immediately gripped by
the lower anchorage, while at the sametime the upper anchorage opened. The load
was thus moved in a step-by-step process.
The unique self-gripping concept of the
motive unit anchorages provided a maximum level of inherent safety.
(Refer to Figs. 5 and 6, Photo 5)

Composite Metal Decking Slab
Construction
The composite metal decking floor slab isa mixed construction system employing asteel sheet which serves as shuttering for
concrete and reinforces the slab partially,
replacing the tensile reinforcements. Thissystem was applied throughout the podium
superstructure slabs including the mega
truss area.
Steel profiles are fixed onto the steel
floor beams and serve as a work platform,
thereby allowing trafficking in good working and safe conditions before the concreteis laid. Once the profiles have been installed, the underside of the floor becomeswatertight and offers a clean finished appearance.
The shape of the ribs sets the steel profile securely in the concrete. All that wasdone was to finish off the slab with a welded mesh. This system eliminated the use ofreinforcement bars and reduced concrete
usage.

Fig. 6 Mega Truss Work before and after Lifting

Before lift

After lift

After lift

Photo 5 Mega truss work before and after lifting
November 2011 Steel Construction Today & Tomorrow 18

Special Report

Great East Japan Earthquake— Proposal of Steel-structure Technologies and Methods for Use in
Restoration and Reconstruction —In order for the earthquake-stricken districts of Japan to regain their former vitality and asense of safety, it is urgent that a vision for their restoration and reconstruction be found.
For its part, the Japanese steel industry has accumulated steel-structure technologies
and methods with excellent disaster-preventive, economical and environmentally friendly
performance characteristics. Capitalizing on these technologies, the industry believes thatit can contribute to the pressing task of reconstructing and restoring towns and infrastructures so that they are resistant to disaster.
The distinctive features of steel structures are: the high strength and good workability
peculiar to steel products, ease of transport, stable mass supply of shop-manufactured
structural members, and precise and highly reliable product dimensions and quality. Bymaking the most of these features, steel structures offer the advantages of: reduced construction terms made possible by on-site construction, excellent landscaping performancedue to a high degree of freedom in design, and being able to create flexible space. Further,
the combined use of concrete, timber and other materials allows for the creation of safer
structures.
Under current conditions, the Japan Iron and Steel Federation is offering proposals forthe application of steel-structure technologies and methods in restoration and reconstruction projects that are now being worked out, typical of which are the following projects(refer to the figure below):● Improvement of disaster-resistant public and emergency facilities
① Seismic- and tsunami-resistant podiums and steel-structure emergency buildings;② Highly seismic-resistant school facilities of steel construction● Rapid restoration of seismic-resistant housing③ Steel-framed houses with shorter construction terms● Improvement and early restoration of coastal and port/harbor facilities,
measures against earthquakes and tsunamis
④ Port/harbor renewal using steel products; ⑤ Seismic reinforcement of piers, seawalls and breakwaters using steel products; ⑥ Reinforcement of existing bridge piersusing steel pipe and sheet piles; ⑦ Seepage seawall using steel pipe and sheet piles;⑧ Measures against liquefaction of ground inside coastal seawalls● Improvement of emergency bases of operation allowing quick disaster
response⑨ Floating emergency centers (Megafloat: floating steel structure)

Special Issue
Advanced Large-span Construction
1
Steel: The Leading Player for Enhanced Large-span Hybrid Structures
4
SkyPark		 ―A Huge Rooftop, Steel Structure
Spanning Three High-rise Towers―
8
Osaka Station City		 ―Large-scale Domed Roof Installedon Station Platform―
12 Asahikawa Railway Station
		 ―Structural Design of Open Largespan Station Building―
15 ION Orchard		 ―Mega Steel Truss Structure Spanning MRT Station―

COVER(upper left) Domed roof of Osaka Station City (fordetails, see page 8); (upper right) Open andbright platform at Asahikawa Station (page 12);(lower left) SkyPark in Singapore (page 4); (lower
right) ION Orchard in Singapore (page 15)
A magazine published jointly by
The Japan Iron and Steel Federation
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103-0025, Japan
Phone: 81-3-3669-4815 Fax: 81-3-3667-0245
Chairman: Eiji Hayashida
URL http://www.jisf.or.jp
Japanese Society of Steel Construction
Yotsuya Mitsubishi Bldg. 9th Fl., 3-2-1 Yotsuya,
Shinjuku-ku, Tokyo 160-0004, Japan
Phone: 81-3-5919-1535 Fax: 81-3-5919-1536
President: Koichi Takanashi
URL http://www.jssc.or.jp
Editorial GroupJISF/JSSC Joint Editing Group for Steel Construction Today & Tomorrow
Editor-in-Chief: Takeshi Oki
The Japan Iron and Steel Federation● Beijing Office
Room 2206, Jingtai Tower, 24 JianguomenwaiStreet, Chaoyang-District, Beijing 100022, China
Phone: +86-10-6515-6678
Phone: +86-10-6515-6694
STEEL CONSTRUCTION TODAY & TOMORROW ispublished three times per year to promote better
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about the publication. Please address to Lettersto the Editor.

19 Steel Construction Today & Tomorrow November 2011