Title Authors

Commentaries/

Outline of Recommendations for Diagnosis and RepairMethods of Fire-damaged Buildings by AIJ

Commentaries/

Stipulation of Structural Eurocodes and Influence of Systemand Contents of Eurocodes

Technical reports/

Design Method of Reinforced Concrete Segment of ShieldedTunnel Using Steel Fiber and Hybrid Fiber

Construction records/

Design and Construction of New Main Office ofOBAYASHI CORPORATION Technical Research Institute

Construction records/

Renaissance Plan 1 at Hibarigaoka―Development for renovation of existing reinforcedconcrete structures―

Construction records/

Underpinning for Reconstruction of Tokaido ShinkansenViaducts in Tokyo Station

Ikuo ISHIKAWA, YasuhiroFUCHITA, Fumiaki ENDO andTakayoshi HIRATA

Akihiko KUSAKABE, HiroyukiONOGUCHI, Taro YOSHIKAWA

Concrete Journal, Vol.48, No.10, Oct. 2010

Masatomo YOSHIDA, KenichiIKEDA, Shusuke KUROIWA andAkihiro SAKAGUCHI

Tatsuo MIOKE, KenichiHORIGUCHI, NaoyukiFUKUURA , Tsuyoshi MARUYAand Yoshifumi HATTORI

Taichiro KAWANISHI

Yukikazu TSUJI

Concrete Journal Vol.48, No.10, pp.3-9, Oct. 2010/ Copyright c̑ Japan Concrete Institute

ˠemailʽyoshida@gbrc.or.jpˡ

Keywords: fire-damaged investigation, fire-damaged diagnosis, fire-damaged classification,

suffered classification, heated temperature, fire resistance, reinforced concrete

Architectural Institute of Japan published “Recommendations for Diagnosis and Repair Methods of Fire-damaged Buildings” in February 2010, with the aim of demonstrating considerations and standard methods on the diagnosis and repair of fire-damaged buildings. This report shows the outline mainly around a reinforced concrete (RC) building of the publication.

In general, RC structures are said to have excellent fire resistance and be less damaged by fire than other structures. However, in order to consider reuse or, repair/reinforcement after, it is important to assume exposed temperature of concrete members

as well as reinforcement before diagnosing degree of damage of each member accurately. Two types of inspection are conducted. Primary inspection is mainly visual observation. Secondary inspection is material tests or structural tests such as concrete core sampling test, reinforcing bar sampling test, UV spectrum method, loading test, vibration test and etc. UV spectrum method targets admixtures in concrete to estimate exposed heat temperature. Exposed heat temperature distribution in the direction of concrete depth is estimated by the analytical curve. Class of fire damage for each member is evaluated based on several test results. Suffered class of buildings is determined according to fire-damaged class of members.

Commentaries

Outline of Recommendations for Diagnosis and Repair Methods of Fire-damaged Buildings by AIJ

Masatomo YOSHIDA*1, Kenichi IKEDA*2, Shusuke KUROIWA*3 and Akihiro SAKAGUCHI*4

*1 Principal Adviser, Product Certification Center, General Building Research Corporation of Japan, Dr.E. *2 Group Leader, Environment & Technical Solution Div., Shimizu Corporation, Dr.E. *3 Chief Research Engineer, Technology Center, Taisei Corporation, JCI Member *4 Deputy Head, Fire Engineering Lab., General Building Research Corporation of Japan, JCI Member

Table.1 Fire-damaged Classification of members Definition Damage

affecting RC Conditions

No effect is found on structural durability and durability.

No damage condition

1 No damage 2 Finishing work such as coating material

remains on all area

Damage such as durability reduction by surface deterioration is found. But no effect on structural durability.

Damage in finishing work area

1 Damage in finishing material 2 Adhesion of soot or lampblack on

building frame 3 Estimated exposed heat temperature of

concrete surface : 300 degC or less

Small effect on structural durability. (can be reused with light repair.)

Damage no-reaching to rebars

1. Color charge to pink 2. Minute cracks 3. Estimated exposed heat temperature of

concrete surface: 300 degC or more

Large effect on structural durability. (can be reused with repair)

Damage in bond with main rebar

1. Width of cracks on the surface : several mm

2. Exposition of a part of main rebar

Serious damage on structural durability. (members must be changed)

Substantial damage such as large exposed part of rebar

1. Slabs (a part of or all parts) drop 2. Buckling of main rebar 3. Remarkable deflection 4. Ratio of measured natural vibration to

calculated natural vibration of one at sound condition: less than 0.75

5. After conducting loading test: ratio of residual deformation to maximum deformation at loading test: 10 to 15% or more by JASS5 method

Table.2 Suffered Classification of Buildings

Suffered class Definition A No fire effect on structure. B Structure is damaged by fire. Possible to reuse by repair. C Structure has possible risk of collapse. Difficult to reuse. Fig.1 Investigation diagnosis flow

Event of ͻire

Preliminary investigation

Primary investigation (Mainly visual observation)

No damage

Damage is onlyin finishing part

Secondary investigation

Damage is limited to surface

Damage in bond with main rebar

End of investigation

Fire-damaged Class of members

Yes

Yes

Yes

Yes

Yes

Yes

No

Yes

No

No

No

No

No

No

Inspection of appearanceSuffered classʽ

C or not?

Substantial damages such as main rebar buckling is obvious

Substantial damage suchas large exposed part of

rebar

Concrete Journal Vol.48, No.10, pp.10-17, Oct., 2010/ Copyright c̑ Japan Concrete Institute

ˠemailʽtsuji@ce.gunma-u.ac.jpˡ

Keywords: Structural Eurocodes, EN, CEN, ISO, CPD, CPR , CEN/ TC 250, LWI

The stipulation of first European standards by CEN (European Committee for Standardization) is in its final stages. Every country has withdrawn his national design codes which conflicts with Eurocodes by the end of March 2010. The TC 250 (Structural Eurocodes) was established within the CEN in 1990 and the stipulation of the so-called Eurocodes have been carried out within the TC 250. The names of the various Eurocodes are shown in Table 1 and the mutual relationship between them is shown in Fig. 1. By examining this figure and table we can see that standards have been stipulated for the design of concrete structures by SC2 (EN1992, Eurocode 2), the design of steel structures by SC3 (EN1993, Eurocode 3), and the design of composite steel and concrete structures by SC4 (EN1994, Eurocode 4).

The basic principle behind the stipulation of these Eurocodes is based on the concepts contained in the ISO 2394(General Principles on Reliability for Structures). In EN1991-1 (Loads and Actions in the Design of Structures), the main emphasis is on design methods using partial safety coefficients in the limit states design method. With regard to concrete structures, standards have been established for concrete quality, production, control and concrete materials by TC 250 and TC 104 (Concrete). In the countries of the EU and countries that are part of the EFTA (European Free Trade Association), all previous standards have been abolished and replaced by the European Standard

(EN) system. There have been examples of EN draft proposals

being submitted as ISO draft proposals. An example of this occurred in June 1998 when the prEN206 was introduced by Norway (the country overseeing that SC) as a New Work Item Proposal (NP) in ISO/TC71/SC3 that had been dormant for the previous ten years. These kinds of things are only going to increase from that time in the various TC and SC of ISO, meaning that each country must move quickly to participate effectively and pertinently in ISO standard stipulation procedures.

................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

....................................................................................

Commentaries

Stipulation of Structural Eurocodes and Influence of System and Contents of Eurocodes

Yukikazu TSUJI*1

*1 Prof., Dept of Civil and Environmental Engineering, Gunma University, Dr E., JCI Member

Table 1 Eurocodes (European Structural Standards) EN1990 Eurocode : Basis of Structural Design EN1991 Eurocode1 : Actions on Structures EN1992 Eurocode2 : Design of Concrete Structures EN1993 Eurocode3 : Design of Steel Structures EN1994 Eurocode4: Design of Composite Steel and Concrete Structures EN1995 Eurocode5 : Design of Timber Structures EN1996 Eurocode6 : Design of Masonry Structures EN1997 Eurocode7 : Geotechnical Design EN1998 Eurocode8 : Design of Structures for Earthquake Resistance EN1999 Eurocode9 : Design of Aluminum Structures

EN 1990

EN 1991

EN 1992 EN 1993 EN 1994

EN 1995 EN 1996 EN 1997

EN 1997 EN 1998

Structural Safety

Serviceability

Durability

Loading and Actions on Structures

Design and

Detailing

Geotechnical Design

Seismic design

EN 1990

EN 1991

EN 1992 EN 1993 EN 1994

EN 1995 EN 1996 EN 1997

EN 1997 EN 1998

Structural Safety

Serviceability

Durability

Loading and Actions on Structures

Design and

Detailing

Geotechnical Design

Seismic design

Fig. 1 Links between the Eurocodes

Concrete Journal Vol.48, No.10, pp.18-26, Oct., 2010/ Copyright ○c Japan Concrete Institute

（email：t-mioke@ce.taisei.co.jp）

Keywords: shielded tunnel segment, fiber reinforced concrete, steel fiber, hybrid fiber,

tension softening relation

Recently, reinforced concrete segments (RC segments) of shielded tunnel are required to be wide and thin in terms of reducing construction cost. On the other hand, RC segments have some problems which are occurrence of cracks and dropping out of concrete chips under construction. It is known that the resistance of RC segments to cracking and chipping can be enhanced by adding of steel fiber or hybrid fiber, which consists of steel and organic fiber. The bridging effect thanks to fiber in concrete, contributes to increasing the flexural and shear strength of the RC segments as well.

RC segments of shielded tunnel with fiber reinforcement have been applied to more than 30 projects outside Japan, since around 1970. In Japan, segments of this type are gradually coming into use.

This report shows structural design method for the application of RC segments of shield tunnel with fiber reinforcement. The method has been developed through element tests aimed at determining a tension-softening curve and verification to structural member test results.

Figure 1 provides a comparison between RC segment and newly developed RSF/RHF segment, where the reinforcing material is, respectively, steel and mixed steel-organic fibers.

The calculated flexural strength and deformation performance using this design method were compared with the results of loading tests on 20 beams and full-size segments. The ratio of observed strength to calculated strength is 1.01 and the standard deviation is 0.09. Adequate safety in design can be secured by taking into account various safety factors. Figure 2 compares the calculated strength and deformation performance against the loading tests.

The presented design method for fiber-reinforced RC segments is simple and useful, because it can be composed by using conventional sectional design method, simply by making allowance for the stress-strain relation based on the tension softening

curve of the fiber-reinforced concrete. Further, this design method is expected to prove suitable for wider application and different fiber material conditions by confirming the material and structural performance according to the scheme presented here.

Technical reports

Design Method of Reinforced Concrete Segment of Shielded Tunnel Using Steel Fiber and Hybrid Fiber

Tatsuo MIOKE*1, Kenichi HORIGUCHI*2, Naoyuki FUKUURA *3, Tsuyoshi MARUYA*4 and Yoshifumi HATTORI *5

*1 Research Engineer, Technology Center, TAISEI CORP., JCI Member *2 Research Engineer, Technology Center, TAISEI CORP., JCI Member *3 Chief Research Engineer, Technology Center, TAISEI CORP., Dr.E., JCI Member *4 Chief Manager, Technology Center, TAISEI CORP., Dr.E., JCI Member *5 Manager, Design Dept., Civil Engineering Div., TAISEI CORP.

0

10

20

30

40

50

60

70

0 10 20 30 40 50 60Deflection (mm)

Load

(kN

)

ExperimentCalculationDesign

H=150mm,pt=0.44%，steel fiber 0.5Vol.%

Fig.2 Comparison of experiment and analysis

組 立 鉄筋

RC Segment

RSF/RHF Segment

Abbreviation of lateral reinforcing barReduction of longitudinal reinforcing bar

Fig.1 Comparison of RC and RSF/RHF segment

Concrete Journal Vol.48, No.10, pp.28-33, Oct., 2010/ Copyright ○c Japan Concrete Institute

（email：fuchita.yasuhiro@obayashi.co.jp）

Keywords: ultra high strength CFT column, ultra high strength concrete, ultra high strength steel, high-ductility and high-strength mortar

OBAYASHI CORPORATION Technical Research Institute was built on 1965 in Kiyose-city. However, the experimental research facilities were spread among 17 buildings, so reconstruction was carried out to efficiently connect them. This reconstruction adopted many environmental and safe-relief technologies, and utilized two new technical components: “ultra-high-strength CFT columns”, and “SLIM-crete Bridge”.

To achieve open and flexible space, the main structural frame is arranged on one side. The columns supporting open space are CFT columns constructed of ultra-high-strength concrete and steel. The two bridges crossing over the third floor is constructed of high-ductility, high-strength mortar “SLIM-crete”.

First, the ultra-high-strength CFT (Concrete-Filled steel Tube) columns are constructed of ultra-high-strength concrete and ultra-high-strength steel. The concrete developed 160 MPa compressive strength and the steel developed 780 MPa tensile strength. The fireproof coating decreased the finish thickness. The Ultra-high-strength CFT columns provided a comfortable space with a large span and high ceiling level, not only reducing the amount of materials but also enabling construction based on long-life design and eco-friendly architecture.

Next, SLIM-crete is a high-ductility, high-strength mortar, of more than 170 MPa compressive strength and more than 11 MPa tensile strength. It is a material called Ultra-high-strength Fiber-reinforced Concrete (UFC). Ordinary UFC must be cured at high temperature, and there are many limitations in its applications. In contrast, SLIM-crete can be cured at normal temperatures because of its special mixing recipe. Therefore, it is more widely applicable and less expensive to place for both insitu and precast concrete. These records summarize SLIM-crete. Furthermore, we describe the execution, structural performance, and fireproof

performance examined in an example of application to a prototype structure.

Fig.1 Facade of Main Office

Fig.2 Interior of Main Office

Fig.3 Ultra-high strength CFT column

Construction records

Design and Construction of New Main Office of OBAYASHI CORPORATION Technical Research Institute

Ikuo ISHIKAWA*1, Yasuhiro FUCHITA*2, Fumiaki ENDO*3 and Takayoshi HIRATA*4

*1 Director, Construction Office on Re-maintenance of Technical Research Institute, Obayashi Corporation*2 Senior Research Fellow, Technical Research Institute, Obayashi Corporation, JCI Member *3 Group Leader, Design Division, Obayashi Corporation, JCI Member *4 Associate Senior Research Fellow, Technical Research Institute, Obayashi Corporation, JCI Member

Ultra high strengthsteel

Second floor

Third floor

Ultra high strengthconcrete

SLIM-crete Bridge

CFT Column

Concrete Journal Vol.48, No.10, pp.34-40, Oct. 2010/ Copyright ○c Japan Concrete Institute

Keywords: reinforced concrete structures, existing structures, demolition, renovation, demonstration tests

Urban Renaissance Agency has managed and operated about 760,000 leased apartments. To respond to the declining number of children, aging of society, the advent of a smaller population and fewer households, among other social changes, the Agency developed the UR Rental Housing Stock Renewal and Restructuring Policies (December 2007) for renewing and reorganizing its leased housing stocks, as valuable assets shared by the people of Japan.

Instead of the conventional approach in which renewal policies are adopted uniformly based on the time of construction of a housing complex, the features of housing complexes and regional communities, appropriate measures to deal with the market environment, and a number of other conditions are taken into comprehensive consideration, for improving the existing stocks of housing using flexible and diverse methods.

Japan Housing Corporation, the predecessor corporation of Urban Renaissance Agency, was founded in 1955 to respond to demand for housing during the period of rapid economic growth in Japan. Housing complexes that were supplied in especially large volumes between around 1965 and 1975 account for about half of the leased housing stocks of Urban Renaissance Agency. Medium-rise apartment buildings with staircases account for the majority. Nearly 40 years have passed since these apartment complexes were built, and the issue or reorganizing these stocks for renewing the housing complexes has arisen.

Numerous issues are found with medium-rise residential buildings with staircases, such as lack of

elevators, low floor and ceiling heights, low noise and heat insulation capacities, and other problems that conventional repair and housing unit renewal alone cannot address. To resolve these issues, Renaissance Project 1 attempts comprehensive technological development in a number of different areas, to bring together residential stock renovation technologies in all areas.

In the course of developing renovation technologies, residential buildings targeted for demolition in rebuilding projects are used for conducting demonstration tests by business entities in the private sector that responded to calls for technical proposals, and also for conducting demonstration tests planned and designed by Urban Renaissance Agency. Test construction has completed at Hibarigaoka Danchi Residential Complex (Higashi-Kurume City, Tokyo).

At Hibarigaoka Danchi Residential Complex, three residential buildings targeted for demolition were used for the demonstration tests on residential stock renewal. For Buildings A and B, the Urban Renaissance Agency presented the basic items of renovation, performance, renovation costs and other performance conditions, and called for technical proposals from private sector companies. The examination committee comprising outside experts and Urban Renaissance Agency chose Takenaka Corporation as the joint research partner. On the other hand, Urban Renaissance Agency chose themes and renovation methods for Building C that were different from those for Buildings A and B, and conducted research based on its plans and designs.

Construction records

Renaissance Plan 1 at Hibarigaoka ―Development for renovation of existing reinforced concrete structures―

Taichiro KAWANISHI*1

*1 Urban and Housing Technology Research Institute, Urban Renaissance Agency

Photograph : View from Southeast (Hibarigaoka Danchi Residential Complex)

after before

Concrete Journal Vol.48, No.10, pp.41-46, Oct., 2010/ Copyright ○c Japan Concrete Institute

Keywords: Tokaido Shinkansen,Underpinning

Tokyo station is one of the busiest stations in Japan.

More than 1 million passengers use this station every day. Moreover, it is the starting terminus of Tokaido Shinkansen, which is used by an average of 190 thousand passengers per day. Structure of this station consist 3 island platforms serving 6 tracks. Around Tokyo terminal, a lot of big redevelopment projects have been proceeding such as construction of skyscrapers. Responding to the situation, JR Central also has been implementing reformation of station structure and shopping mall for the better customer services (Fig.1). This paper shows underpinning work for reconstruction of Tokaido Shinkansen viaducts, implemented due to removal of Tetsudo Kaikan building for the reformation.

An underpinned viaduct, which is named Tokyo Station Chubu Viaduct, has 3 tracks and 4 pillars. It’s a tier, 4 span, beam-slab, and rigid frame structure. The viaduct was partly supported by adjacent Tetsudo Kaikan building, which was going to be removed. This underpinning work is the most difficult and largest one among past underpinning works for Tokaido Shinkansen structure, considering that underpinning four consecutive viaducts in the direction of track partially was required (Fig.2). In addition, there were two difficulties.

Fig.1. Aerial Photo of the construction area.

Firstly, during the underpinning project, Tokaido

Shinkansen service was not allowed to stop during operating hours. To overcome such a difficult situation, we took a plan that existing beams at the level of track 19 were underpinned by temporary support steel bents,

while the Tetsudo Kaikan building was removed and new permanent piers were constructed (Fig.3).

Fig.2. Plane figure of the construction site.

Secondly, each pillar of Tokyo Station Chubu Viaduct was not connected, but its foundations were combined with next viaduct under the ground. In such situation, there were many risks that existing structures may settle down, responding to a partial settlement occurred by the underpinning work. Therefore, extremely-delicate control of the vertical and horizontal displacement had been conducted. Despite of these difficulties, the temporary support construction was completed in March, 2009. The permanent support construction was finished in July, 2010. The project was completely finished considering keeping safety of passengers and the reliable railway service of Tokaido Shinkansen.

Fig.3.Sectional views of each construction process.

Construction records

Underpinning for Reconstruction of Tokaido Shinkansen Viaducts in Tokyo Station

Akihiko KUSAKABE*1, Hiroyuki ONOGUCHI*2, Taro YOSHIKAWA*3

*1 Central Japan Railway Company *2 Central Japan Railway Company *3 Central Japan Railway Company

For Shin-Osaka

For Kanda

TokaidoTokaido ShinkansenShinkansen

Tetsudo Kaikan buildingTetsudo Kaikan buildingYaesu Development

Marunouchi Side

Yaesu Side

For KandaFor KandaFor Shin-OsakaFor Shin-Osaka

Tetsudo Kaikan building

19#19#18#18#

17#17#16#16#

19 （about 130m）19 （about 130m）

YaesuCentral Gate