No. 17 R DECEMBERDECEMBE 20062 0 0 6

A QQuarteryuartery PublicationPublication ofof TThehe JapanJapan IronIron andand SteelSteel FederationFederation • JJapaneseapanese SocietySociety ofof SteelSteel ConstructionConstruction

Building Construction Aesthetic Architecture Aesthetic Architecture —Attractive Buildings Employing State-of- the-Art Materials and Technologies— by Dr. Eng. Mitsugu Asano, Chairman of JSSC’s Committee on the Design, Construction and Manufacture of Aesthetic Architecture (NIKKEN SEKKEI) Through the investment of great ingenu- designers employed by design firms and duce future tasks and developments, and to ity in both design and production, diverse construction companies. The examples call attention to the creativity of structural performance characteristics have been cited in the report were recommended by designers. More specifically, the report fea- incorporated into recent architectural the member companies and were selected tures technical information and data that spaces, configurations, and designs in order from among recent design projects con- are useful in creating aesthetic architectural to make structures as aesthetically attrac- ducted by those companies. The main structures. tive as possible. Further, hybrid structures object of the report is not a discussion or The report offers examples of five struc- consisting of steel and other materials are comparison of these examples. Rather, it tural categories that can be made more widely used in these buildings. is to illuminate the effort involved at the attractive. The Committee on the Design, Con- stage of realizing a design concept, to intro- ● Improving the attractiveness of an entire struction and Production of Aesthetic frame system Architecture, established by the Japanese ● Improving the attractiveness of roofing Society of Steel Construction (JSSC), has (terrace) recently published a report on technologies ● Improving the attractiveness of façades that promote appealing architecture. The ● Improving the attractiveness of structural committee’s members consist of structural elements (members, connections) ● Improving the attractiveness of small- scale structures The following introduces nine major Nagoya Dome examples of aesthetic architectural struc- tures that were recently built in Japan.

Kuroshio Arena

Roppongi Hills Arena Building Mikimoto Ginza 2 National Art Center

Seibu Dome Marunouchi Oazo’s Atrium International Library of Children’s Literature

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Kuroshio Arena —Energetic Roofline, Warm Interior Space, and Seemingly Transparent Façade— by Hisanori Taniguchi,

Structural Plan are attached in a V-shaped pattern that In particular, due to studies conducted from This building is a competitive swimming extends from the bottom of the trusses to both design and manufacturing perspec- stadium constructed in Kochi, Shikoku, the ceiling. This configuration not only tives on the steel castings used for the space for the 2002 National Athletic Meet. It calls to mind the Kuroshio Current and column bases, these castings were manu- has a one-story basement, three stories the vigor of sport but also gives the interior factured in eight different configurations above ground, and a large roof with a long- space a feeling of warmth. The roof trusses using one set of molds. side span of 122 m, a short-side span of are supported on both ends of the large 98 m, and a trapezoid plane of 32 m. It is space by space steel columns, and because Bright, Richly Transparent Space equipped with a 50-m pool, an infant pool, the walls are formed using Vierendeel The walls are composed of three layers: a year-round hot-water pool with Jacuzzi, trusses, the interior has a feeling of trans- external sashes, support trusses, and mov- and a training room. The 50-m pool can be parency. able wooden louvers. Because Vierendeel converted for use as a gymnasium, thereby steel trusses (SM490A) were adopted for making the arena functional for a wide Unidirectional Roof Supported by the wall support structure, the need for wall range of uses in addition to swimming, Space Columns braces was eliminated. such as other types of sporting competi- In order to promote the smooth transfer of tions and various events. stress where multiple structural members The roof trusses are unidirectional steel come together, cast steel members (JIS structures to which beams and diagonal G5102: SCW480) were adopted for the truss members made of laminated Kochi Cedar beam cross sections and the column bases.

Hybrid truss composed of steel frames and beam and diagonal members made of laminated Kochi Cedar

Full view of Kuroshio Arena

50-m pool and space column

Cast steel member adopted for the truss Cast steel member adopted for the space beam cross section column base Vierendeel steel truss used for wall

2 Seibu Dome —Large Roof Blends Well with Surrounding Environment— by Satoshi Higuchi, Corporation

The most distinctive feature of the struc- five-degree pitch. The components used for dome’s center section (145 m in diameter) tural plan for Seibu Dome was the remod- the dome’s construction consisted of a steel consists of a single-layer lattice made of eling of the existing open-roofed stadium pipe-structured single-layer lattice frame steel pipe (558.8 mm in diameter, 14 mm into a closed dome arena, during two con- membrane over the dome’s center sec- in wall thickness) arranged in 7.5-m grids. secutive November-to-March off seasons. tion, a doughnut-shaped radial steel space- Like a globe of the Earth, the single-layer To accomplish this, the remodeling was truss frame surrounding the membrane, lattice is laid out in a grid of latitudinal and undertaken in two stages. In the first stage, and 4.5~12 m-high V-shaped columns that longitudinal lines. In about 300 cross sec- metal roofing consisting mainly of steel support the roof. In order to build the roof tions where these lines intersect, cast steel frames was built over the seated sections, structure during two off-season periods, fittings were adopted. and in the second stage, membrane roofing the structural plan allowed for the existing Single-layer lattice Structural Elements frame membrane was extended above the playing fields. stadium to be used when the first stage of Boundary ring Radial steel Upper ring construction was completed. space-truss frame Outline of Structural Plan Step-shaped truss Main beam In the planning of the dome, the whole Structural Plan for Membrane Roof V-shaped column lower ring section was configured to tilt at a The frame membrane that covers the Lower ring

Plane and Section Metal roof in the first stage of construction Membrane roof in the second stage of construction

Membrane roof in the second stage of construction

Metal roof Existing building in the first stage Full view of Seibu Dome of construction

Completion of the first stage of Lift up of the roof in the second stage of construction construction Cast steel fittings

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High-strength bolts were used for flange Construction of Metal and of the ring-shaped trapping method. Instal- joining where the metal fittings for the Membrane Roofs lation of the membrane roofing in the sec- cross sections connect with the steel pipes. Installation of the metal roofing in the ond stage of construction was achieved by The flange surfaces of the metal fittings first stage of construction—assembly and assembling the grid frames on the ground were machined with appropriate angles installation of steel frames weighing more and then hoisting the 2,100-ton roof struc- to make the fittings’ surface, as a whole, than 8,000 tons—was implemented more ture into place by means of the lift-up closely resemble a sphere. quickly than expected due to the adoption method.

Dentsu Building —High-rise Building with Asymmetrical Planes, Super Mega-frame System, and Two Kinds of Vibration-damping Devices— by Masayuki Yamanaka,

Building Outline Fig. 1 Appearance of Dentsu Building (left: south side; right: west side) In order to provide both functionality and appearance befitting the start of the twenty- first century, three concepts were taken into consideration during construction— 100-year service, symbiosis with the envi- ronment, and energy savings. To realize these concepts, the motto “low impact and high contact” was emphasized and allowed to influence every stage of design and con- struction, from planning to completion. In conformance with the urban plan- ning for SIO-SITE (a comprehensive urban development project), the Dentsu Build- ing provides not only office space but also visitor-intensive superb amenities that inte- grates commercial and cultural facilities, which thus creates a deep bond with the surrounding community—high contact. Also, with its boomerang shape, this high- rise building not only offers scenic beauty and attractive urban landscaping; it also longer return periods. This is why the seis- control short-side span-direction deforma- meets the need to minimize such adverse mic design of the Dentsu Building seeks tion in which bending deformation is great- effects on the surrounding area as electri- to secure sufficient structural strength est. cal disruptions and strong tunnel-effect by exceeding the Levels 1 and 2 external The major structural features of this winds—low impact. forces that are commonly adopted. unique building with such an asymmetrical The aboveground section of the build- plane configuration (Fig. 2) are cited below: Structural Outline ing has a boomerang-shaped plane and ● Adoption of a CFT (concrete-filled steel In order to realize the major design concept measures about 120 m in long-side span, tube) structure having a concrete strength of “100-year serviceability,” a highly func- about 41 m in short-side span, and 210.087 up to 80 N/mm2 tional, highly durable building was targeted m in height. The towering ratio (height-to- ● Use of SA440 fire-resistant steel (80 mm that would ensure safety against wind and width ratio) is about 5.0 in short-side span, maximum plate thickness) for the inner seismic forces and offer comfortable habit- compared to 1.7 in long-sides span, thereby atrium to realize a steel-frame structure ability. In designing a building that is to be giving the building a rather slender profile without the need for fire protection (Fig. 5) serviceable for more than 100 years, it is (Fig. 1). Because of this, a key element of ● Securing stable energy absorption capac- necessary to assume external forces with the structural plan was determining how to ity by expanding the width of the girder

4 ends Fig. 2 Outline of structural plan ● Securing short-side span horizontal rigid- ity by use of a super mega-frame system Vibration-control device Mega-truss Vibration-control with integrated plane, elevator and struc- 㩷 device tural plans

● Realization of seismic-resistant frames (Standard floor) that employ two kinds of dampers, each Steel frame (CFT structure)㩷 effective in controlling shear deformation Assembled column and bending deformation (Figs. 3 and 4) 㩷 ● Securing habitability by use of a vibra- tion-control device installed at the top of the building Vibration-damping device 㩷 㩷 These technologies and methods were Mega-truss +㩷 adopted to produce a high-rise building Bent damper Tie beam㩷 㩷 with high seismic resistance and were implemented with close attention to quality control. (Common floor)

Fig. 3 PYO damper for shear deformation Fig. 4 Damper for bending deformation Fig. 5 Inner atrium

Mikimoto Ginza 2 —Façade with Architecturally-designed Window Openings— by Yasuhiro Hayabe,

Structural Plan abstraction throughout the entire building between the two steel plates. The result- This building is composed of tube trusses structure” is freely expressed in the build- ing high-strength structure possesses yield that wrap around all four rectangular sides ing. strength peculiar to both steel and concrete. (14×17 m each) of the building with the wall In addition, because the surface layers of The two steel plates are tightly joined by tie structure, which is of composite assemblies the walls are steel plate, they present a flat bars. Wall details are shown in Table 1. made of steel plate and concrete. These joint-free façade that, in combination with The reason for making the street-side walls have irregularly-shaped openings the finish coat, produces a symbolic build- steel plates 12 mm in thickness and the that, according to the architects, “present ing that is very strong in spite of its thin neighboring site-side steel plates 9 mm mobile patterns like those that catch trem- outer walls about 200 mm in thickness. was to reduce welding strain occurring in bling moments.” The Mikimoto Ginza 2 the road-side plate to a minimum and to building breaks with the multi-story con- Structural Details of Steel Plate- balance rigidity and strength between the struction by means of the layered structure Concrete Wall road-side and neighboring site-side plates approach, frequently adopted for commer- The steel plate-concrete walls are of com- because of the many openings in the walls. cial building construction, and the “solid posite structure with concrete sandwiched The single-layer steel plate-concrete

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wall is divided into 32 unit panels. The size Table 1 Dimension of Steel Plate and Concrete Composite Walls of each unit panel is set at 2.4 m in width Outer Inner Concrete Wall Space Structural plate plate thickness thickness between × story height (4.5 or 5.0 m). The structure section Designation Story thickness thickness stud bolts tc (mm) T (mm) of one of the unit panels is shown in Fig. 1. t1 (mm) t2 (mm) B (mm) 400 (φ22) After the unit panels were manufactured at South side SCW4 6~9 12 6 200 218 200 (φ13) the shop, they were installed at the site and West side SCW2 3~5 12 9 200 221 300 (φ22) then filled with concrete after weld-joining. (Street side) SCW 1~2 12 12 200 224 400 (φ22) In order to realize the “flat joint-free North and east sides SCW5 6~9 9 6 200 215 300 (φ19) façade” envisioned by the architects, min- (Neighboring- SCW3 1~5 9 9 200 218 300 (φ19) ute care was paid during installation. site side) Rib wall SCW6 1~9 6 6 200 212 200 (φ13)

Erection piece Inner steel plate t=6.0~12.0 Stud bolt Φ22×200 Retaining the wall thickness while at the same time combining steel plate with concrete Channel C-200×80×7.5×11 H-shape 200×100×5.5×8 The unit panel is structured by steel members that wrap four sides. Openings are fabricated on site by cutting. Erection adjustment bolt The bolt is attached to control the space between the unit panels. Outer steel plate t=9.0~12.0 About 6-mm camber is shop-provided to prevent the unit panel’s convexity from occurring. Building model (courtesy of Ito Toyoo Architectural Design Fig. 1 Structure of Unit Panel Office)

Installation Appearance Inside view

Nagoya Dome —Bright, Open Stadium Employing Single-layer Lattice Trusses— by Mitsuo Seki,

Building Plan layer steel-frame lattice dome. At the center roof satisfies not only the height limit The Nagoya Dome was designed to sym- of the dome is a 5,000-m2 roof of double- imposed by shade regulations but also the bolize the Tokai area of central Japan and walled glass top light that makes the dome need for an interior height of at least 60 m was completed in February 1997 in Nagoya. bright and produces a feeling of abundant for baseball games. Other advantages are It is a multi-purpose facility that seats spaciousness. The amount of incoming light the minimization of air conditioning costs 40,500 fans for baseball games. Because is controlled by a retractable rolled screen and the cost cutting of a steel-frame roof of its location in an urban housing area, located beneath the glass top light. due to reduced roof thickness and fewer the roof was designed as a closed, single- The adoption of a single-layer lattice structural members.

6 Structural Plan where six lattice pipes meet, each pipe is to the stresses applied. Node design was The dome has a concentric circle-shaped rigidly weld-joined to a spherical cast steel tested by finding the stress bearing ratio plane. The center-to-center diameter node. of each member through FEM analysis between the outermost peripheral columns and 1/2-scale model experiments. Further, is 229.6 m and the height is GL+66.9 m Roof Design performance tests and cast steel-SM grade at the roof’s highest point. The roof has a The following studies were made in design- steel weldability tests were carried out diameter of 187.2 m and uses mainly steel ing the single layer-type roof. using full-scale experimental models. pipes to form a single-layer steel-frame lat- ● Assessment of buckling strength and tice dome. The roof’s geometrical configu- safety, taking into account unmatched Construction ration is L=183.6 m in center-to-center dis- configurations caused by out-of-plane In order to reduce high-elevation work, tance between tension members, the roof deformation, etc. improve weld quality, secure construction height is H=32.95 m in member center-to- ● Effect of construction efficiency on the quality and shorten the construction term, center distance, and the rise ratio (H/L) is roof trusses a lift-up method was adopted whereby the set at 0.179. ● Shape of and design method for steel pipe lower dome structure and the roof could The roof lattice consists of isosceles tri- joints be simultaneously constructed. As a result, angular shapes that, being nearly equilat- ● Seismic safety of a large-scale single- only 30 months were needed to complete eral triangles about 10 m on a side, consist layer roof the Nagoya Dome. The roof, weighing of steel pipes measuring 650 mm in diam- Because of the three-dimensional con- 13,000 tons, was hoisted 23 m upward eter (SM490A). In order to make the mem- centration of large-diameter steel pipe using jacks. bers be of uniform strength, the pipe wall members on the joints, spherical cast steel thicknesses gradually increase from 19 mm nodes (1,450 mm in diameter and 740 mm Source of information at the center of the dome to 28 mm at the in height: SCW480) were adopted. All Mutsuo Sahashi: “Space-truss Structures” Vol. periphery. Steel pipes (SM490B) 900 mm the nodes are identical in shape and have 4, May 1995; Edited by Mitsuo Seki, Takanaka in diameter and 50 mm in wall thickness either of two wall thicknesses according Corporation are used for the tension rings. At junctions

Spherical length = 198.9m Rise H/L = 0.179 㲈0.23 H = 32.95m Tension ring

1.0 L = 183.6m 79° R = 144.3m Section θ = 50.5° Plane

A 㲈 29.000m2

Appearance Geometrical Configuration of Roof Installation of node section

ℓ θ = 3.95° Triangular basic grid

9.94m ℓ 㲈19.8m 㲈

Triangular unit Inside view Roof Division Method and Member Node Drawing Arrangement

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Roppongi Hills Arena —The Roof Serves for Diverse-purpose Event Facilities— by Takahiro Kido, YAMASHITA SEKKEI INC.

Structural Plan the truss frames together, beams, and indi- ● Level adjustments at the ends of the can- This structural system consists of an oval vidual tension members for stiffening. tilevered truss frames can easily be made ring measuring 54.1 m in length and 41.3 In order to provide efficient support for by pulling in the backstay cables. m in width that is supported by six col- the wide-span cantilevered beams, the can- ● The cantilevered truss frames permit umns, cantilevered truss frames differing tilevered truss frames rest on the top plinth structural expression characterized by a in hanging length from 25.7 m to 40.1 m, an of each column and are provided with a dynamic and floating appearance. external perimeter oval ring that connects backstay cable that is pin-connected to the Further, in addition to the backstay top of the column in a manner to maintain cables, frontstay cables are provided for two proper balance. frames on each end of the six cantilevered The adoption of this structural system truss frames. This is intended to secure the offers the following advantages in terms of soundness of the whole frame construc- structure and construction: tion against unexpected loads. To this end, ● The elimination of rigid joints for con- the initial tension established at the design necting the columns to the cantilevered stage is introduced into both cables. truss frames allows enormous stress to

be transformed via the cantile- Retractable membrane vered trusses into tensile force in (Folding type) the backstay cables. ● This, in turn, substantially reduces Closed state the amount of stress transferred to the columns, thereby enabling a Fixed membrane roof relatively slender column frame. Open state Full view of Roppongi Hills Arena Fixed metal roof

(L=36.1 m~40.1 m) (O member) (Lu member)

(R member) (LL member) Ly

(C member) 24.0 m 20.0 m 㲈 *Arrow line: Opening and closing direction h

㲈 (B member)

h (G member) Lx Roof Structure Lx=54.1m (Four center frames) Lx=41.3m L=25.7m Canti-truss Cross section (Lu member) φ 152.4×16～φ203.0×28 (LL member) φ 203.0×16～φ203.0×28 (R member) φ 89.1×4. 2～φ152.4×16 (O member) φ 152.4×16 Column Cross section

(FS member) 23.0 m (C member) φ 267.4×55 20.0 m 㲈

h ～

㲈 (G member) BH-250×180×19×32 36

h (BS member) Tension Member Cross section (BS member) 2-φ 30(1× 37) SUS cable (FS member) 2-φ 20(1× 19) SUS cable (Both-side frames) (BR member) 1-φ 25～1-φ32high-strength tie rod

Dimensions of Structural Members Column head-cast steel joint

8 National Art Center —Glass Façade with a Three-dimensional Curved Surface Supports the Roof— by Yasuyoshi Hitomi, NIHON SEKKEI, INC.

Structural Plan exhibition building. The advantage of mini- 3 m by horizontal tie truss beams. Taking The National Art Center came to comple- mizing horizontal forces offered by a base- into consideration the deformation tracking tion in 2006 as an art museum used exclu- isolation structure allows for a column-free properties of sashes, criteria for the story sively for exhibitions, without any perma- space in the atrium, thereby making pos- drift were established at 1/120 or under. nent collections. The building plan consists sible the transparency of the façade. Time-history response analysis at the of a 130-m by 60-m exhibition room and time of a large earthquake reveals that the an irregularly shaped 3,000 m2 atrium. Structural Mullions maximum horizontal acceleration gener- Considering the possibility that artwork of For the structural mullions, flat steel pieces ated would be 286 cm/s2 and the maximum worldwide value would be on exhibit, the were bent in their strong axial direction vertical acceleration would be 581 cm/s2, or building incorporates base-isolation tech- using cold pressing, and the 3D-truss thus about one third that of an ordinary seismic- nology to protect against earthquakes. prepared (with different curvatures up to resistant structure. Based on this, the allow- 10.4 m) were weld-joined. Because no spec- able stress design to ensure safety was Façade Design ifications are available for steel plate over implemented on the assumption of a hori- The atrium, standing 23 m high, has a glass 100 mm in thickness that is readily bent and zontal quake of 0.3G and a vertical quake façade with a three-dimensional curved suitable for welding, custom-made products of 0.6G. surface. Its roof is supported by a total of equivalent to SN490C materi- 115 slender columns of flat steel (115 mm als were adopted. ×515 mm) placed at approximately 2-m The structural mullion intervals around the outer periphery of the frame is stiffened against roof (structural mullion system) and by the buckling at a pitch of about

FB-50×6(SS400) FB-50×6(SS400) FB-50×6(SS400) FB-50×6(SS400) Full view of National Art Center 840

300 332 250 258 FB-50×6(SS400) FB-115×515 (SN490CM)

Coupling nut (S45C) P-60.5×11 (STK400) (with self-locking set screw) (with self-locking set screw) Turn buckle Cast steel

Connector (SCM435H) 350 (SN400A) (SCW480) P-42.7×10 (STK400) Connector (SCM435H) (with self-locking set screw) M30 Glass façade with a three- About 2 m dimensional curved surface Mullion Slender column of flat steel

Assessment range Truss beam Out of assessment range

Upper structure Steel frame Rigid steel-frame structure with brace

Foundation structure Reinforced-concrete structure Pile foundation Pile: On-site reinforced-concrete pile Bearing stratum: Kazusa group (below GL–30 m) Base-isolation device member Framing Elevation Lead rubber bearing

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Marunouchi Oazo’s Atrium —A Column-free Expanse Created by Balanced Cantilever Framing System— by Ichiro Ogawa and Tamotsu Ito, Mitsubishi Jisho Sekkei Inc.

Overall Structural Plan trusses protrude, like a frame built using Truss End Details Located at the center of the Marunouchi the balanced cantilevered method, that Since four steel pipes meet at each end of Oazo complex is the shop and restaurant crisscross a ship-shaped truss composed the ship-shaped truss—a representative building, which contains an atrium that of four steel pipes on the upper and lower form of the roof frame, the joints are made rises 40 m or more in height and defines a sides. In order to secure bilateral balance in compact by the use of steel castings. The space that clearly distinguishes the com- a perpendicular direction, a spiral rope and cast steel section is shaped so that one end plex as a whole. The atrium roof measures a tie rod are attached to the end of each arm is integrated with the boxed column and approximately 20 m×25 m and is somewhat of the cantilever truss to prevent rotation. the other end rests on the column top plate. fan shaped. The roof of the 7-layer atrium The use of curtain walls hung from the The cast steel pipe corresponds in grade has a finish of glass top light. Exterior cur- roof frame using flat bars eliminates the to SN490C (328.0 in diameter×45 mm), tain walls for five layers from third to sev- need for column-like perpendicular mem- and the attached steel pipe conforms to enth stories (height: about 30 m) are hung bers for façade walls. For wind beams, unit STKN490B (318.5 in diameter×28 mm). from the top of the roof. trusses are adopted as light members; they Shop welding was used to connect the cast consist of cross-shaped hot-extruded steel steel pipe and steel pipe, while field weld- Balanced Cantilever Framing as chord members and a combination of ing was used only for connecting parts of System steel bars and ball joints as diagonal mem- the steel pipe. For framing the atrium roof, eight plane bers. Photo: Kawasumi Architectural Photograph Office Photo: Kawasumi Architectural Photograph Office Photo: Kawasumi Architectural

Perspective view of entire building frame Outside view of atrium Inside view of atrium

Y9 Crisscrossing truss M Y8 Post 0 Tie rod Tie 0 3

, Y7

6 Ship-shaped truss

L 0

0 Y6 0 ,

3 Ships-shaped K truss

0 Y5 0

0 Flow of force , 6

J 7th-floor beam 29,900 Y4

Y3 Glass 0 0 6 , 4 1 Spiral rope Y2 5,300 Y1 H 3rd-floor truss 7,600 7,600 X1 X3 X4 X6 X7 X2 X5 Post 7,600

22,800 9 10 11 12 Roof Framing Plan Truss Framing Elevation Edge of ship-shaped truss

10 International Library of Children’s Literature —Solid Posts Combining a Bright and Transparent Atrium with Sashes— by Hiroshi Yamamoto, NIKKEN SEKKEI

Structural Design ing building. required for the new building was achieved It has been discussed how an old masonry by providing the PC bars with sufficient and brick building, designated as an histori- Glass Design tension force to remain viable at the maxi- cal asset of the Metropolitan Gov- In contrast to the conventional exterior mum assumed fire temperature. ernment, is gaining new life as a library of walls with their rich design detail and children’s literature. In order to affect the impression of weightiness, efforts were Structural Details reutilization of this building, a base-isolated made to avoid the use of design detail in FR steel flat bars with no added fire pro- retrofitting method was adopted that not the materials of the glass enclosures form- tection, measuring 50×180 mm, were used only preserves the conventional interior/ ing the added corridor and entrance hall. as posts for the glass enclosures on the 1st, exterior structural design but will also Care was also taken to secure the visibility 2nd and 3rd floors. An initial-stage tension ensures its structural safety. of the façade of the original building. The force of 2.6~3.8 tf was introduced into PC In renovating the building as a new flat bars used as support posts for the exte- bars that were 9.2 and 11 mm in diameter. international library of children’s literature, rior glass were reinforced using prestressed FR steel flat bar posts were also arranged it was necessary to provide information/air- concrete (PC) bars, which also serve as the at 900-mm intervals in the entrance hall, conditioning/disaster-prevention systems support structure for the floor. cafeteria, and 3rd-floor lounge. For these and a site for exchanges between people Fire-resistant (FR) steel with no added sections too, PC bars were adopted as the and goods. To meet this need, a service fire protection was adopted for the flat reinforcing members. entrance composed of a glass enclosure was bars comprising the major structural mem- added that passes between two core shafts bers, and the structural safety of the build- Photo: The Japan Architects Co., Ltd. of reinforced concrete and along the exist- ing during fire was verified. The safety

Photo: The Japan Architects Co., Ltd. Photo: The Japan Architects Co., Ltd.

Front view Court-side view

Third-floor lounge

Photo: The Japan Architects Co., Ltd. Curtain wall FR steel (without fi re protection) 50 mm thick x 180 mm wide

Sectional Drawing of Curtain Wall FR steel post and PC bar Glass cafeteria

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Steel Products for Aesthetic Architecture

Fire-resistant Steel

Fire-resistant (FR) steel has greater high- Fig. 1 Comparison of High-temperature Strength of FR Steel and Conventional temperature strength than conventional Steel steel. Because FR steel products conform 600 to the room-temperature specifications FR steel of steel products used in building struc- 500 tures, any design work or construction that employs FR steel products can be per- Tensile strength Conventional steel formed in a manner identical to conven- 400 FR steel ) tional steel products. A comparison of the 2 high-temperature strength of FR steel and 300 conventional steel is shown in Fig. 1. Yield stress The temperature at which the yield point falls to 2/3 the specified room-temperature 200 strength (325 N/mm2) is approximately Strength (N/mm 350°C for conventional steel, but is in the Conventional steel neighborhood of 600°C for FR steel. Two- 100 thirds the specified room-temperature strength corresponds to the allowable stress for sustained load. During a fire, suffi- 0 0 200 400 600 800 cient strength is required to support the self-weight of a building, that is, the allow- Temperature (°C) able stress for sustained load. To meet this Table 1 Grade and Mechanical Properties of FR Steel demand, FR steel guarantees a high yield point of 600°C, which is more than 2/3 the Yield strength YR Elongation Symbol of Tensile strength specified value at room temperature (F grade Thickness (N/mm2) Thickness Test (N/mm2)(%) (%) value). The grades and mechanical proper- (mm) (mm) piece ties of FR steel are shown in Table 1. 6 ≤ t ≤ 16 245 ≤ t ≤ 16 No.1A 18 ≤ SM400A-FR 16 < t ≤ 40 235 ≤ 400 ~ 510 – 16 < t ≤ 50 No.1A 22 ≤ The available products and sizes of 16< t ≤ 100 215 ≤ 40 < t No.4 24 ≤ FR steel are: plates with thicknesses of 6 6 ≤ t<12 235 ≤ – 6 ≤ t ≤ 16 No.1A 18 ≤ mm to 100 mm and H-shapes with flange SN400B-FR 12 ≤ t ≤ 40 235 ~ 355 400 ~ 510 – 16 < t ≤ 50 No.1A 22 ≤ thicknesses up to 40 mm. The two basic 40 < t ≤ 100 215 ~ 335 ≤ 80 40 < t ≤ 100 No.4 24 ≤ 2 t =16 No.1A 18 ≤ strength levels are: 235 N/mm (Grade 35) 16 < t ≤ 40 235 ~ 355 SN400C-FR 400 ~ 510 ≤ 80 16 < t ≤ 50 No.1A 22 ≤ 2 40 < t ≤ 100 215 ~ 335 and 325 N/mm (Grade 50). For plate thick- 40 < t ≤ 100 No.4 24 ≤ nesses greater than 40 mm, FR steel plates 6 ≤ t ≤ 16 325 ≤ t ≤ 16 No.1A 17 ≤ are available that have been manufactured SM490A-FR 16 < t ≤ 40 315 ≤ 490 ~ 610 – 16 < t ≤ 50 No.1A 21 ≤ using TMCP (thermo-mechanical control 40 < t ≤ 100 295 ≤ 40 < t ≤ 100 No.4 23 ≤ process) and that feature no reduction in 6 ≤ t < 12 325 ≤ – 6 ≤ t ≤ 16 No.1A 17 ≤ SN490B-FR 12 ≤ t ≤ 40 325 ~ 445 490 ~ 610 – 16 < t ≤ 50 No.1A 21 ≤ the specified value at room temperature, F 40 < t ≤ 100 295 ~ 415 ≤ 80 40 < t ≤ 100 No.4 23 ≤ value (specified design strength). t =16 No.1A 17 ≤ 16 ≤ t ≤ 40 325 ~ 445 SN490C-FR 490 ~ 610 ≤ 80 16 < t ≤ 50 No.1A 21 ≤ 40 < t ≤ 100 295 ~ 415 40 < t ≤ 100 No.4 23 ≤ 40 < t ≤ 75 325 ~ 445 40 < t ≤ 50 No.1A 19 ≤ TMCP325B,C-FR 490 ~ 610 ≤ 80 75 < t ≤ 100 325 ~ 445 40 ≤ t No.4 23 ≤ 40 < t ≤ 75 355 ~ 475 40 < t ≤ 50 No.1A 19 ≤ TMCP355B,C-FR 520 ~ 640 ≤ 80 75 < t ≤ 100 355 ~ 475 40 ≤ t No.4 21 ≤ *H-Shape: Thickness of flange is under 40mm YR=Yield strength/Tensile strength

12 Steel Castings

Castings are classified into two kinds Next, as shrinkage occurs during cast- is obtained. After these gating systems are according to chemical composition: cast ing, a pattern is manufactured taking into taken off and heat treatment is conducted, iron and cast steel. While the carbon con- account the shrinkage allowance. In cases the castings are trimmed with grinder and tent of iron castings somewhat exceeds 2%, when the pattern is repeatedly used in the machined, which are then shipped to users. that of steel castings is around 0.2%, which same configuration, wood and other mate- (Refer to Fig. 2) approximates the carbon content specified rials capable of withstanding repeated use for ordinary rolled steel products. Because are used to manufacture the pattern, while Applications of this, in steel building construction, cast- formed polystyrene is sometimes intro- The major application of castings is in ing components for steel structures that duced for the pattern when the configura- large-size industrial machinery parts and require welding are generally steel castings. tion for each product is not same. shipbuilding, with only a few percent being Further, castings are sometimes classi- Patterns manufactured in this way are used in building structures. Because of this, fied into two different kinds according to embedded in sand to which the binder is only a few foundry companies position the production method: steel castings for added and the sand hardens within approx- steel castings for building structures as a welded structures (JIS G5102) and centrifu- imately10 minutes. Generally, sand molds major product line. Nevertheless, as can be gal casting steel pipes for welded structures are prepared in two sections—upper and seen from their use in the joints of struc- (JIS G5201). The Building Standard Law lower molds—so that the wooden pat- tural and finishing members of Sun Dome of Japan specifies the materials that can be tern can be easily removed. After harden- Fukui (see Photos 1 and 2), steel castings used for building structures and SCW480 ing of the upper and lower sand molds, often function as structural materials for grade steel castings are often used, which the wooden pattern is taken out of the the joint components in space-frame struc- has similar specifications to those of ordi- sand. The upper and lower sand molds are tures and serve an important role in “aes- nary rolled steel (Table 1). repaired for minor nicks and provided with thetic architecture.” sand burning-preventive measures, and Production Processes are joined in preparation for pouring of the The production processes for both iron molten steel. castings and steel castings are nearly the In producing steel castings, molten same. They include the lost-wax method in metal, which is made from steel scrap using which a sand mold is prepared by affixing electric arc fur- sand to a wax mold, and a method whereby nace, is used. After Fig. 1 Example of Casting Plan a wood mold is embedded in sand that is being poured from then hardened with resins or by decom- the pouring cup, Riser Down gate pression. Of these, the furan-resin casting the molten metal method is introduced below. is also supplied First, the casting method and cast- from risers because Sand mold ing plan (Fig. 1) are devised based on the it suffers liquid production drawing, which is redrawn to shrinkage. After Runner the design drawing to allow for shrinkage the molten metal of the casting materials. Should the cast- cools down in the ing plan is not appropriate, defects such as sand mold and the shrinkage cavities will occur in the prod- mold is removed, uct. To avoid critical problems such as this, casting with run- risers and runners are arranged in a proper ner and riser etc. manner taking into account the past experi- Casting Gate ence and through solidification simulation analysis. Although it is not unusual to pro- Table 1 Mechanical Properties of SCW480, Steel Castings for Welded Structures duce a product yield for castings of about (JIS G5102) 40%, the measures mentioned above are Yield point Tensile strength Charpy impact test Grade Elongation (%) mandatory in order to avoid the occurrence (N/mm2) (N/mm2) value at 0ºC (J) of inner defects. SCW480 275≤ 480≤ 23≤ 27≤

13 BBuildinguilding ConstructionConstruction

Fig. 2 Production Process for Steel Castings

Confirmation of production drawing Manufacture of upper and preparation of casting plan and lower patterns Setting of patterns in the metal frame

Blending of melting materials Mixing by continuous mixer

Preparation of molding materials Molding Photo 1 Inside view of Sun Dome Fukui

Molten metal

Covering of upper Casting and lower molds

Heat treatment

Cutting off of riser Finishing of cast product

Inspection Frame dismantling (mold removal) Photo 2 Expanded inside view (the cross- shaped sections are composed of steel castings)

Cleaning (shot blasting) Packing/Shipment

Hot-extruded Steel Shapes

The extrusion of nonferrous metals such as since the installation of copper was conducted in the 19th century. a hot-extrusion machine However, the practical extrusion of steel in 1960, mainly to man- was difficult to implement because lubri- ufacture stainless steel cants capable of withstanding high tem- seamless pipe and tubes peratures were unavailable. Then, in 1941, and hot-extruded steel the French company Ugine successfully shapes. In particular, extruded steel using glass as the lubricant. the manufacture of hot- Since then, the hot-extrusion process has extruded steel shapes made remarkable developmental strides as in Japan has relied a method for producing stainless steel and solely on this machine. special-alloy pipe and tubes and specially- The hot-extruded steel shaped steel shapes. (See Photos 1 and 2 shapes produced in and Fig. 1) Japan meet diverse Photo 1 Hot-extrusion machine This method has been used in Japan needs, and the related

14 Fig. 2. Billets that Fig. 1 Sectional Configurations of Hot- have been reheated extruded Steel Shapes to around 1,200ºC are inserted into the container; then, steel shapes that have been processed into deformed products are extruded from the front die caliber using water pres- sure. Hollow steel shapes are made available by the use

Photo 2 Hot-extruded products of mandrels. The die alone production technologies have been accu- determines shape configuration (the die mulating for many years now. plus mandrel when producing hollow products). In contrast to the rolling pro- Production Process and Available cess, the hot-extrusion process does not Dimensions require the preparation of many rolls. The outline of a production process that The most outstanding feature of the uses a hot-extrusion machine is shown in hot-extrusion process lies in the small- lot production of items having specially- Fig. 2 Extrusion of Hot-extruded Steel Shapes designed configurations. The grades of steel available for hot Die extrusion include not only carbon steel Dummy block and alloy steel but also difficult-to-process Die backer Ram Billet stainless steel. Regarding sectional dimen- sions, it is necessary to limit the product Progressive direction of ram Die holder diameter to a maximum of 215 mm, while Container Glass lubricant the available length of each shape depends Solid shape on its cross section, up to a maximum of 11 m (Table 1). By f u lly ut ili z i ng t hese Dummy block dimensional features, steel shapes are sup- Die Ram plied monthly in about 500 configurations Die backer (averaging 2 tons/lot) that meet customer- Billet tailored design requirements, not standard configurations. Die holder Mandrel Container Glass lubricant Applications Hollow shape Hot-extruded steel shapes are used in diverse fields—for example, forklift masts, Table 1 Available Sizes for Hot-extruded Steel Shapes parts for machine tools, and joints for steel Circumscribed circle (diameter) 215 mm (8 inches) sheet and pipe piles. In addition, these Thickness 6 mm (0.2 inches) shapes are being increasingly used as both Corner (r) 2 mm (0.08 inches) decorative and structural members in build- Corner (R) 5 mm (0.2 inches) Minimum area (Smin) 300 mm2 ing construction, establishing many appli- Maximum area (Smax) 6,000 m2 cation records in such distinctive buildings Length 1~11 m (3.2~36 feet) as art galleries, museums and other cultural Maximum weight 260 kg/p (574 lbs/p) facilities. Smax is available up to 12,000 m2, when product is as-extruded or not corrected.

15 Steel-structure Harbor Facilities in Asia (Two-part Series: 2) Port and Harbor Development and ODA

by Norihiko Ibuki General Manager, Overseas Project Department Japan Port Consultants, LTD.

Outline of Port and Harbor Projects Simple and Efficient Government.” In harbor development projects involving Funded with ODA compliance with this law, the Japan Bank Japan Port Consultants, LTD. (JPC). Official development assistance (ODA) has for International Cooperation is to be inte- been inaugurated as aid provided by gov- grated into a “new financial organization” ● Development Project for Semarang ernments or government organizations to in fiscal 2008, and the bank’s overseas Port in Indonesia developing countries to assist in economic economic cooperation operations are to be In the development project for Semarang development and welfare improvement. ceded to JICA. As a result, the organiza- Port located on the northern coast of cen- ODA is divided into two categories accord- tions responsible for the administration of tral Java, Indonesia, steel structures were ing to the type of capital flow: bilateral grant aid and loan aid will be unified. adopted for the breakwaters and piers. The aid is provided through direct assistance, Because of their great scale, port and breakwater is designed to support a con- and multilateral assistance is implemented harbor development projects are mostly tinuous steel sheet pile wall using oblique through international organizations. implemented under yen-denominated loan steel pipe piles. In breakwater construc- Bilateral assistance includes grant aid, conditions. But for development projects tion, gravity-type composite breakwaters technical cooperation and loan aid (Japa- such as these that are mainly targeted for are widely adopted that use heavy concrete nese yen loans). In Japan, most grant aid LLDC (Least among Less Developed structures, such as caissons and rubble-type and technical cooperation are implemented Countries), implementation is under grant sloping breakwaters constructed by piling by the Japan International Cooperation aid conditions, albeit for small amounts, up rubbles. Agency (JICA), a non-profit organization taking into account the difficult financial However, at the Semarang Port con- established by Japan’s Ministry of For- condition of the LLDC. struction site, the soft seabed posed many eign Affairs. In addition, most loan aid is According to surveys conducted on hurdles to construction. These included the provided through the Overseas Economic ODA-based port and harbor develop- need for ground improvements to accom- Cooperation Operations of the Japan Bank ments for the last five years (1999~2003) modate heavy gravity-type structures; for International Cooperation. in the field of transportation, these projects difficulty in securing the vast amounts Multilateral assistance includes capital accounted for 36~38% of all ODA projects of good-quality sand needed to replace participation and donations to international in terms of project number. Meanwhile, all the weak stratum; and construction cost organizations. Capital participation and government yen loans, excluding deferred increases related to mixing cement into the donations to international development debt, for the same five years amounted to weak stratum. To overcome these hurdles, organizations are implemented mainly by ¥3,550 billion, of which loans in the trans- steel structure construction was selected. the Ministry of Finance, while donations portation area accounted for about 21%, or and other allotments to various organiza- ¥750 billion. Of this 21%, loans for port and ● Development Project for Kupang tions of the United Nations are controlled harbor development accounted for about Port in Indonesia mainly by the Ministry of Foreign Affairs. 9%, or ¥67.5 billion yen. At Kupang Port located in West Timor, Meanwhile, at a cabinet meeting held Indonesia, an island that sits in front of the on March 10, 2006, a new law was drafted Application of Steel Structures port serves as a breakwater, protecting the — “Law Concerning the Promotion of Introduced below is a description of how port from sea waves. Because vast invest- Administrative Reform for Realizing a steel products have been used for port and ments are required to build breakwaters,

16 most conventional ports have evolved from pier structure has been adopted for the pier ODA for Africa will double in the next river ports. However, in order to accom- structure. (See Fig. 2) three years. He frequently stressed Japan’ modate the trend toward greater ship size s aid doctrine in political speeches and at due to growing social modernization, it ● Development Project for Colombo summit meetings—“In order to support has become necessary to secure the requi- Port in Sri Lanka the efforts of African countries to achieve site water depth for ports. Because islands The development project for Colombo sustainable self-reliance, the Japanese gov- form isolated channels with the appropriate Port, Sri Lanka, involves the construc- ernment will provide the support that these water depth and provide calm sea areas, tion of container berth and terminal in the countries truly require.” there are many cases in which ports and port surrounded by existing breakwaters. In the sub-Saharan area of Africa south harbors in developing countries are located Because the seabed in front of the pier is of the Sahara Desert, there are many LLDC in such geographically blessed sites. comparatively flat and the foundation layer with difficult financial situations; these Kupang Port is located in such a channel is located in shallow water, a caisson-type countries will primarily receive grant aid site, where the sloping terrain of the seabed gravity structure was adopted for the pier. support. However, LLDC with improving is steep and drops precipitously in front of Steel pipe piles were used for the founda- financial conditions can expect to receive the pier. Because of this, a steel pipe-pile tion piles of the land-based container crane. yen loans for their port and harbor develop- structure that is easily adaptable to rugged (See Fig. 3) ment projects. seabed surfaces has been chosen to replace As stated above, in most cases where the gravity-type pier as the pier structure. Japanese ODA and Future Port steel is used in the construction of port (See Fig. 1) and Harbor Development and harbor facilities, steel structures suit- Japanese ODA has hitherto been provided able for the topographical, soil and other ● Development Project for Bitung mainly in support of the developing coun- natural conditions of the port site will be Port in Indonesia tries of Asia. This will remain unchanged adopted. In addition, there are cases where Bitung Port in north Sulawesi, Indonesia, because of the important political and eco- steel structures allow for a narrower work is located at a channel site, like the Kupang nomic relations between Japan and Asia. site than gravity-type structures and where Port. Because of the steep slope of the sea- Meanwhile, then-Japanese Prime Minister they reduce the use of heavy construction bed in front of the pier, a steel pipe-pile J. Koizumi stated in 2005 that Japanese machinery in building port and harbor Fig. 1 Standard Section of the Pier at Kupang Port

17 facilities. Also, in developing countries facilities in developing countries, it will the same time to transfer to them Japan’s where it is difficult to procure adequate be necessary to select structural types that excellent technologies and know-how. It is construction machinery, steel structures are appropriate for the specific conditions thought that the demand for steel structures offer the added advantage of requiring of these countries and areas. It will also be in port and harbor development projects fewer machines for construction. necessary to contribute to the economic will continue to expand in the future. In the construction of port and harbor development of these countries and at Fig. 2 Standard Section of the Pier at Bitung Port

Fig. 3 Standard Section of the Pier at Colombo Port

18 JSSC Special Prize No. 18 MARCHMARCH Awarded for Accomplishments in 20072 0 0 7 Research on the Redundancy of —————— CONTENTS —————— High-rise Steel Buildings On November 16, 2006, the Japanese Society of Steel Construction (JSSC) Aesthetic Architecture Attractive Buildings Employing State-of-the-Art Materials and presented the JSSC Special Prize to the Committee to Study the Redundancy Technologies ------1 of High-rise Steel Buildings (chaired by Prof. Akira Wada, Tokyo Institute of Nine major examples ------2~11 Technology). This award was presented for research conducted jointly with Steel Products for Aesthetic Architecture U.S. counterparts on guidelines for collapse control design and for the subse- Fire-resistant Steel ------12 quent publication of Guidelines for Collapse Control Design. Steel Castings ------13 The destruction of the World Trade Center buildings on September 11, Hot-extruded Steel Shapes ------14 2001, due to progressive collapse attracted wide attention and caused soci- Steel-structure Harbor Facilities in Asia (Two-part Series: 2) etal concern about the safety of steel buildings. To meet this concern, the Port and Harbor Development and ODA ------16 JSSC quickly established in June 2002 the Committee to Study the Redundan- cy of High-rise Steel Buildings with a mandate to design a method that could control progressive collapse in steel buildings. The proposed research was promoted in collaboration with the Council on Tall Buildings and Urban Habitat (CTBUH) of the U.S. In September 2005, COVER these two organizations jointly published Guidelines for Collapse Control Typical aesthetic architecture and steel Design, which presents the world’s fi rst practical design guidelines for con- members used—left above: National Art Center (for details, see page 9); left below: trolling progressive collapse in steel buildings. Guidelines was published not column head-cast steel joint (page 8); only for Japanese users but for overseas users as well. right above: Mikimoto Ginza 2 (page 5), and right below: lounge structure using The research conducted thus far has contributed to the sound develop- uncoated FR steel (page 11) ment of steel building construction technologies both in Japan and abroad. The JSSC holds these accomplishments in high regard and, because of this, presented the current award. Guidelines for Collapse Control Design, available in a three-part series —Design, Research and High-performance Steel Products for Building Con- A quarterly magazine published jointly by The Japan Iron and Steel Federation struction—is covered in detail in issue No. 12 of Steel Construction Today & 3-2-10, Nihonbashi Kayabacho, Chuo-ku, Tokyo Tomorrow. 103-0025, Japan Phone: 81-3-3669-4815 Fax: 81-3-3667-0245 Chairman: Akio Mimura 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: Akira Chihaya URL http://www.jssc.or.jp

Editorial Group JISF/JSSC Joint Editing Group for Steel Construction Today & Tomorrow Editor-in-Chief: Takeshi Katayama

The Japan Iron and Steel Federation ● Beijing Office Rm. 609, Jongtai Tower, 24 Jianguomenwai-Street, Chaoyang- District. Beijing. 100022, China Phone/Fax: (010) 6515-6678 Phone: (010) 6515-6699 (Ext. 30221)

STEEL CONSTRUCTION TODAY & TOMORROW is published to promote better understanding of steel products and their application in construction field and circulated to interested executives and companies in all branches of trade, industry and business. No part of this publication can be reproduced in any form without permission. We welcome your comments about the publication. Please address all correspondences to Letters to the Prof. A. Wada (left) receives the JSSC Special Prize Editor.