The National Science Foundation's (NSF) Tokyo Office periodically receives and disseminates reports on research developments in Japan that are related to the Foundation's mission. NSF-sponsored researchers currently working in Japan prepare many of these reports. These reports present information for use by NSF program managers and policy makers; they are not statements of NSF policy.
Special Scientific Report #00-05 (September 01, 2000)
Shih-Chi
Liu, from NSF Engineering Directorate who is currently
on leave at the University of Maryland's Civil Engineering Department,
prepared the following report. Dr.
Liu and Prof. M. P. Sing of Virginia Polytechnic Institute and State
University visited Japan from June 16-30, 2000, on Japan Society for the
Promotion of Science (JSPS) senior invitational fellowships.
Professor Eizaburo Tachibana of Osaka University served as their
host. Dr. Liu may be reached at
scliu@uam.umd.edu
During
this JSPS sponsored visit to Japan, we visited several teaching and research
institutions and laboratories. The
purpose of this visit was to interact with Japanese scholars working in the area
of earthquake and wind engineering, structural control, and auto adoptive
materials and structures, and to explore the possibility of collaborative
research activities in the near future.
During
this trip we were primarily stationed at three locations in Japan: (1) Kyoto,
(2) Osaka, and (3) Tokyo. The
institutions we visited and activities at these locations are described in the
following paragraphs. The complete
schedule for our trip and formal agendas for the meetings and visits at some of
these locations are attached.
We
arrived in Osaka on June 17 and stayed till June 20.
In
the morning of June 19, we visited Dowa Fire and Marine Phoenix Tower which is
installed with two active-passive composite tuned mass dampers, called the DUOX
system. The building is hexagonal
in plan, and 145.5 meters high with 34 stories (including 3 underground stories,
and a two-story penthouse.) The
building is made of structural steel and part steel reinforced concrete (SRC)
and part reinforced concrete. The
aspect ratio (height/width) is about 4 with fundamental period of 2.88 sec for
vibrations about the weak axis.
The
building was designed by Nikken Sekkei LTD of Osaka Japan.
The chief designer of the building, Dr. Kunio Ukai, and his associates
Mr. Isao Midorikawa and Mr. Kingo Nabesawa were kind enough to allow us to visit
the building and its control system. The
DUOX system was designed by Kobori Research Complex, Inc. of Kajima Corporation
of Japan. Mr. Izuru Fukushima,
Research Engineer, of Kobori Research Complex was also very kind to explain the
technical details of the control system.
The
composite tuned mass damper consists of a primary mass actuated by a smaller
mass. The primary mass is 30 T, and
can move 50 cm in either direction. The
the restoring stiffness is provided by laminated rubber bearing. A damper is also installed between the base of the damper
mass. There are two secondary
masses of 6 T each that act as mass drivers in two orthogonal directions.
The maximum stroke is 100 cm in either direction.
The secondary masses are actuated by a 15 KW servo motor. The mass ratio
of the control system to the building mass is about 0.3%.
The
system primarily controls the wind-induced motions, and can also be used to
control small earthquake induced vibrations.
For wind speed up to 17 m/s (return period of 5 years) the device will
reduce the wind-induced response by 50%. For
higher wind velocities, the device will keep providing control at full capacity;
however, the response reduction will not be as large as for smaller wind
velocities. If the power supply
fails, the system is expected to act as a passive device.
The
system is innovative as it uses the two masses with smaller mass acting as a
primary actuator.
The
second building we visited in the afternoon on June 19 was the Hankyu Chayamachi
Building, also called as the Applause Tower because the building has a theater
on its second floor. The building
is a hotel complex. The building
and the active mass damper system were designed by Takanaka Corporation.
It is the first building of height more than 100 m that was installed
with an active mass damper for wind response control.
The building is 161.1 m high and was completed in 1992.
The innovative feature of the building, besides being the first highrise
building with an active mass damper is that, it utilized the mass of the
helicopter landing pad as the damper mass.
The heliport is supported on the laminated rubber bearings, and is
excited by 4 actuators. There are
also 4 dampers installed, two in each orthogonal directions, between the
heliport mass and the top floor to provide to the active mass damper. The heliport weighs 480 T, with a mass ratio of 3.5% of the
first mode mass. The actuators have a stroke of 35 cm in plus and minus
directions. Mr. Kunio Fukuyama and
Mr. Takatostu Mine explained the technical details of the devices.
A follow up presentation was also made by Dr. Tatsuo Okamoto of Takaneka
Corporation on June 20 on the campus of Osaka University Campus.
On
June 20 we visited the campus of Osaka University, and had technical discussions
with Professors E. Tachibana, Masao Ikeda, and T. Furukawa, and
with Drs. Y. Mukai, Xing, and T. Okamoto.
The presentations were made by Dr. Xing on the suppression of exercise
induced vibrations in high rise buildings, by Professor Furukawa on the control
of floating large structure, by Dr. Mukai on the suppression of wind induced
vibrations by controllable wing, and by Dr. Okamoto on the structural control of
Applause Tower designed by Takaneka Corporation.
Dr. M. P. Singh of Virginia Tech also made a presentation on his research
activities in earthquake engineering and structural control at Virginia Tech.
Dr.
Tachibana and Dr. Singh were encouraged to explore the possibility of starting a
cooperative research program in earthquake structural engineering and hazard
mitigation under the auspices of US-Japan Cooperative Research Program on Urban
Earthquake Disaster Mitigation which is currently in the third year of the five
year initiative at the National Science Foundation in the US and the Japanese
Ministry of Education, Science, Sports and Culture (Monbusho).
We
arrived in Kyoto in the afternoon of June 20 by car.
Our local host in Kyoto were Professor Kenzo Toki and Professor Hirokazu
Iemura of Kyoto University. On June
21, we visited the Department of Civil Engineering and Disaster Prevention
Research Institute at University of Kyoto with Professors Toki and Iemura on
June 21. Professor Iemura and his
graduate student Mr. Shuji Iwata of Japan Railways escorted us to DPRI.
Dr. Yasuhiro Hayashi, Associate Professor with Professor Suzuki,
explained to us the dynamic testing of the full-scale two-story wood-frame
structure. They are also examining
the effect of using energy dissipation material in the structure on its
performance. Dr. Iemura also
explained to us the experimental set up for active control of five-story steel
structure. Dr. Iemura has also
patented a testing apparatus for different types of damping devices under
realistic end conditions. Dr.
Iemura and I also explored the possibility of joint research collaboration under
the US-Japan Cooperative Research Program and the training of graduate students
at Virginia Tech for advanced degree. In
the afternoon on June 21, Dr. Singh and I made separate presentations at Kyoto
University.
On June 22, we visited the Koryaji Temple, a national treasure, with the courtesy of Mrs. Iemura. The main statue in this temple is installed with a three dimensional base isolator. The isolator seemed to be quite effective in reducing the horizontal response; the vertical response reduction is, however, not very high. In the afternoon we left for Tokyo by the Bullet Train.
We
arrived in Tokyo in the evening of June 22, and stayed till June 30.
During this period we visited several universities, research institutions
and labs as follows.
June
23
On
June 23, we visited the University of Tokyo, Departments of Civil and
Architectural Engineering. We had a
very meaningful discussion with Prof. Shunsuke Otani of the Department of
Architecture about the US-Japan Cooperative Research Program on Urban Disaster
Mitigation. The Japan side program
is more focused on research objectives, unlike the US program where the
principal investigators decide the research topics within the broad framework of
the program, and NSF supports the best projects based on a highly competitive
nationwide selection process. On
the Japan side, MONBUSHO selects a principal investigator who then invites other
researchers to join the team. The
Principal Investigator of the program gets the funds, which are sufficient
primarily to conduct coordinating activities.
The funds to do actual research are obtained by the individual
researchers through other sources.
We
also visited with Prof. Yozo Fuzino of the Department of Civil Engineering.
He was very kind to show us his laboratory where he is working on
vibration measurements for system identification using the laser beams, wind
tunnel testing for noise induced by wind flow around high rise buildings in an
urban environment, and wind tunnel testing of a suspension bridge.
The laser beams can be focused at different points on the vibrating
structure, and using the Doppler effect, the velocity measurements can be made.
The displacements can be similarly measured, in fact more easily than the
velocity measurements. The research
on the flow-induced noise is being conducted to predict the effect of a proposed
building on its neighbors when it is finally built.
In
the evening of June 23, we met with Dr. Hirashi Hiriashi and Dr. Modrikawa of
BRI and had the pleasure of having dinner with them.
June
24
On
June 24, we visited Waseda University with Professor Nishitani. We also had the pleasure of meeting with Prof. Masanori
Hamada from the Department of Civil Engineering of Waseda University.
We exchanged information about our research activities.
Professor Hamada described to us a large project from Science and
Technology Agency (STA) he is directing on the topic of “Enhancement of
Earthquake Performance of Infrasturctures based on Investigation Into Fracturing
Process”. Prof. Hamada and Prof.
Nishitani provided to us a CD-ROM containing the reports of the investigations
done by the Japan Society of Civil Engineers on the Kocaeli Earthquake in Turkey
and Ji-Ji Earthquake in Taiwan that occurred in 1999.
It was also a great pleasure to have lunch with Prof. Nishitani and
Professor Hamada.
June
26
In
the morning, we visited the Kajima Technical Research Institute (KaTRI) in West
Tokyo with Mr. Tomohiko Hatata of the Kobori Research Complex of Kajima
Corporation. We had an excellent and illuminating meeting with Dr. Tsunehisa
Tsugawa, Senior Supervisor, and his associates Mr. Koji Ishii, Mr. Tomohiko
Hatada, Mr. Yoshimori Matsunaga and Mr. Tadashi Nasu of KaTRI. Dr. Tsugawa explained the management and research activities
of KaTRI and Kobori Institute of Kajima Corporation, and then conducted a tour
of the KaTRI complex. It is a very
large and modern research complex consisting of several building with a fire
lab, micro vibration lab, large-scale testing lab for pseudo-dynamic testing,
and a six-degrees of freedom 5 meters by 5 meters shaking table for earthquake
testing. The micro vibration lab is
in a base isolated building on laminated rubber bearing with fail-safe supports.
They plan to do a major renovation of the shaking table with modern data
acquisition system at a cost of about 1.5 million US dollars.
After the visit to KaTRI we had a very exquisite lunch hosted by Mr.
Hatata.
In
the afternoon, Mr. Hatada escorted us to design office of Kajima Corporation in
Akasaka. We met with Mr. Yukihiro
Omika, Director and Group Senior Vice President, Architecture and Engineering
Design Group, and his associates. He
explained to us a novel building design concept for the design of highrise
building structures. The design
consists of a central core, which is primarily responsible for carrying the
seismic forces, a set of columns on the opposite faces, and one or more supper
beams on the top of the core with their ends linked to the outside columns
through viscous dampers. The
viscous dampers are used for supplemental energy dissipation.
The design has the advantage of providing a column free space around the
central core, lending a very desirable flexibility for architectural layout.
The floors are designed as flat slabs.
The vertical placement of the floors can be freely adjusted almost like
adjustable shelves to accommodate different story heights at different levels.
The reinforcement details in the core are specially designed to ensure
ductile behavior with monotonically increasing capacity under increasing lateral
loads. The cores designed with such
reinforcement showed no capacity degradation, which otherwise occurs in concrete
members designed with normal reinforcing details.
Although this design seems to lose the advantage of redundancy built in
the moment resisting frames, adequate safety against collapse is ensured by
designing the core with monotonically increasing capacity with enough ductility
capacity. Kajima Corporation has
already designed two building with this concept.
One more building is under construction.
A new 42-story building using a combination of moment resistant frame and
this new concept is under design stage.
In
the evening of June 26, we visited the Central Research Institute for
Construction Technology. We met
with Dr. Shin Okamoto, Director General of the Institute, and had the dinner
hosted him. Bill Blanpied of the
NSF Tokyo Office also joined us for dinner.
We also had the pleasure of meeting with Dr. Jotaro Iwabuchi who is
working with Dr. Okamoto. Dr.
Iwabuchi had graduated for Virginia Tech, Department of Civil Engineering.
June
27
June
27 was a free day for us. We got
some time to organize. Around noon,
we also got some time to do a little shopping in Tokyo.
In the evening, we met with Dr. Hiroshi Yamahara, President, Ohsaki
Research Institute, Inc. and Dr. Toshiaki Fujimori, Director, Shimuzu
Corporation Institute of Technology Director.
We had a dinner meeting with them and Professor Billie F. Spencer of
Notre Dame University who was also visiting Japan on JSPS invitational
fellowship.
June
28
In
the morning, we met with Professor Kazuhiko Kawashima, and visited the
Department of Civil Engineering at the Tokyo Institute of Technology. Prof. Kawashima is an expert in seismic design of bridges,
and had developed a patented variable damping device for retrofitting of bridge
girders, and is well-known in the US for his original research contributions.
He is continuing his research activities in the active and passive
control of bridge structures. It was very interesting to see his laboratory in Tokyo
Institute of Technology, and testing of damped bridge models in the labs.
The research associates of Professor Kawashima also made presentations on
their research activities.
In
the afternoon we visited Keio Univesity and met with Professor Kazuo Yoshida,
Professor in the Department of System Design Engineering and Professor Akira
Mita of the Graduate School of Science and Technology.
Prof. Yoshida described the semi-active base isolation system used in a
new Keio University building. It is 7-story steel and partially steel and
reinforced concrete building of about 31 meters height and 14.4 meters depth. We
got the opportunity to see the isolation system installed in the building
basement. The isolation system
consists of 64 laminated rubber bearings, 24 passive dampers, and 8 semi-active
dampers.
Professor
Mita is well-known for his innovative work in the area of fiber optic sensors.
He described his research activities in the area of distributed sensing
for health monitoring, and in the development of the FBG acceleration sensors,
pressure sensors and sensors for liquefaction occurrence through pore water
pressure measurements by fiber optic sensors.
In the evening, we were invited for a dinner hosted by Professors Yoshida
and Mita where we also had the pleasure of meeting and interacting with
Professor Yoshikazu Kitagawa of Keio University.
June
29
On
June 29, we visited the Nagatsuta Campus of Tokyo Institute of Technology with
Professor Kazuhiko Kasai, Professor of Structural Engineering, Structural
Engineering Research Center of Tokyo Institute of Technology (TIT).
Professor Kasai was very kind to arrange several presentations on the
research activities at TIT in the area of seismology, microzonation, and passive
control for earthquake loads. Prof.
Hiroaki Yamanaka, Dept. of Environmental Science and Tech made a presentation
about profiling of seismic basins using the inverted models.
Prof. Seo Kazuoh of the Dept. of Built Environment made a presentation
about a microzonation technique using artificially created micro-tremors by bore
hole explosions. Professor Saburoh
Midorikawa of the Department of Built Environment made a presentation about
seismic microzoning of Manila Metropolitan area in Philippines and his
investigation on the near field ground motion in the Chi-Chi Taiwan Earthquake.
Professor Tatsuo Ohimachi of the Department of Built Environment made a
presentation on his research activities on the boundary element modeling of the
Kobe Earthquake motions and tsunami simulation.
Professor Akira Wada, Head of the Structural Engineering Research Center,
made an interesting presentations on the “Basic Idea of Passive Control of
Structures” and on the title of “Columns Have to Support Gravity Weight of
Superstructures”. Interesting
concept of design of joints with enough ductility in the tension mode was
presented to take advantage of the isolation effect.
A novel design concept with yielding joints with ductile plate was also
shown for the design of very tall storage structures.
Prof. Satoshi Yamada of the Structural Engineering Research Center
presented a very interesting testing device for full scale testing of the
dampers installed in multi-story frames. In
this testing device, although only a part of the frame is tested, the effect of
the remaining part is ingenuously included through the use of an appropriately
selected weight, a spring, and a loading beam to simulate the remaining part of
the structure.
Professor
K. Kasai is very well known in the United States for his innovative work in the
area of passive dampers such as visco-elastic and unbonded braced dampers.
Professor Kasai made an excellent presentation on his recent research
activity in the area of different types of passive dampers (displacement
dependent systems, velocity dependent systems, mixed dependency systems), his
work on unified performance assessment of various systems, and his collaborative
activities with various industry groups. Professor
Kasai invited me to consider visiting TIT on a Senior Visiting Research Scholar
Program that is sponsored by TIT; I intend to consider it seriously in the
following years.
June
30
On
June 30, we returned directly to the United States.
This
visit was an intellectually rewarding experience to meet with several
outstanding Japanese educators, researchers, engineers, and research
administrators. The visit enabled
us to meet with new researchers as well as strengthen our professional and
personal relationships with old professional colleagues and friends.
We are deeply impressed by the dedicated professionalism of our Japanese
colleagues. We again note with
delight that the research conducted by our Japanese colleagues is of highest
caliber and of immediate practical relevance.
We are specially obliged to each individual we met on this visit for
sharing their valuable time, scientific data, and information freely.
We have certainly learnt a lot in technical and social terms from our
Japanese colleagues. We are looking
forward to developing a more fruitful and intellectual relationship with many
Japanese colleagues we met on this trip. We
hope to share with them our own professional experience through collaborative
research activities in the near future.
Schedule
in Osaka and Kyoto
June 17 (Sat)
Dr. and Mrs. Liu: Arrive Osaka
Kansai Airport (KIX) at 16:43 Flight No UA809
Prof. Singh: Arrive Osaka Kansai Airport (KIX) around 16:30
Move
from KIX to Senri Hankyu Hotel by Dr. Furukawa’s Car. (Furukawa Cellular
Phone: 090-6322-3237)
STAY: Senri Hankyu Hotel (P:
06-6872-2211; F: 06-6832-2161)
June 18 (Sun) AM/PM Free Time
17:00
To be met at Senri Hankyu Hotel by Prof. and Mrs. Tachibana, Dr. and Mrs.
Mukai, and Dr. Xing of Osaka University. Japanese style “Tofu” dinner at
restaurant Ume-Nohana, which is located near Senri Hankyu Hotel.
June 19 (Mon)
9:30
To be met at Senri Hankyu Hotel by Prof. Tachibana
AM Visit structural control building (Dowa Phoenix Tower) with Prof Tachibana,
Dr. furukawa, Dr. Mukai, and Dr. Xing.
12:00 Chinese style lunch
PM Visit another structural control building (Hankyu International)
June 20 (Tue)
10:00
To be met by Dr. Furukawa at Senri Hankyu Hotel and to be taken to Osaka
University. Discussion with Prof. Inoue, Prof. Tachibana, Prof. Ikeda, Prof.
Baba, Dr. Furukawa, Dr. Mukai, Dr. Xing, and some Japanese Engineers.
12:00 Western style lunch
14:00 Move to Hotel Granvia
Kyoto by Dr. Furukawa’s Car
STAY:
Hotel Granvia Kyoto (P: 075-344-8888; F:
075-344-4400)
June 21 (Wed)
Visit Kyoto University
Prof.
Iemura of Kyoto University will arrange some meetings. Details of the meetings
will follow from Prof. Iemura.
June 22 (Thu)
AM
Visit Kyoto University
PM Move from Kyoto to Tokyo by bullet express train
Schedule
in Tokyo
June
22 (Thu) Move from Osaka to Tokyo by bullet express train
Taxi from Tokyo Station to the Hotel New Otani
STAY: Hotel New Otani
(P: 03-3265-1111; F: 03-3221-2619)
June
23 (Fri)
09:50 Take Taxi from the Hotel to Yotsuya Sta.
Take Subway from Yotsuya to Todaimae
Walk from Todaimae to Univ. of Tokyo Hongo Campus (10 min.)
(Map to be FAXed to the hotel)
10:30 Visit Dr. Yozo Fujino (Engeering Building No. 11
5th Fl.)
and Dr. Shunsuke Otani, University of Tokyo
(P: 5841-6095)
17:00 To be met by Dr. Hisashi Hiraishi, BRI, at the Hotel
(P: 0298-64-6688)
June
24 (Sat)
10:00 To be met by Dr. Akira Nishitani of Waseda University
in the Lobby of the Tower
Building Dr.&Mrs. Liu is staying
(P: 5286-3286)
June
25 (Sun)
13:00 To be picked up by Dr. Kawashima at the Hotel
Drive and dinner
June
26 (Mon)
0920 To be met by Dr. Hatada of Kajima Co., Ltd.
in the Lobby of the Tower
Building Dr.&Mrs. Liu is staying
(Dr. Singh, please come to the
above Lobby.)
Visit Kajima's Technical
Research Institute in Chofu
Lunch at the Institute
Return to Kajima Co.
(P: 5561-2311)
15:00 Visit Dr. Takuji Kobori, Kajima Co., Ltd.
Take taxi to Dr. Okamoto's Institute
(Map to be FAXed to the hotel)
(P: 5561-2420)
16:30 Visit Dr. Shin Okamoto
at the Japan Association of Representative General Contractor
(Tokyo Nissan Minato Building, 1-6-34, Konan, Minato-ku)
(P: 3458-1011)
June
27 (Tuesday)
17:00
To be met by Dr. Toshi Fujimori and Dr. Hiroshi Yamahara at the hotel
(See attached instruction)
(P: 3820-5500)
June
28 (Wednesday)
0930
To be met by Dr. Kawashima at Hotel New Otani and to be taken to
Tokyo Institute of Technology - Ookayama Campus
(P: 5734-3810)
1300 To be picked up by some one from Keio University
Visit Dr. Yoshida/Dr. Kitazawa/Dr. Mita
of Keio University - Hiyoshi Campus
(P: 045-563-1141 x-43087)
Evening
With Drs. Yoshida/Kitazawa/Mita, et. al.
June
29 (Thursday)
0930
To be picked up by Dr. Kasai at the Hotel
Move to the Tokyo Institute of
Technology - Nagatsuda Campus
Presentations/Discussions
Lunch
Presentations/Discussions (Details to be FAXed separately to the hotel)
(045-924-5512)
1800 Dinner with Dr. Kasai, and the presenters/discussants
June
30 (Friday)
1615 Depart
from Narita by UA#852
Details of the Visit to
Tokyo Institute of Technology, Nagatsuta Campus
Host: Kazuhiko Kasai, Professor of Structural Engineering
Structural Engineering Research Center
Tokyo Institute of Technology
Nagatsuta, Miclori-Ku, Yokohama 226-8503, JAPAN
Tel:
Japan 45-924-5512, Fax; Japan 45-924-5525
E-Mail: kasai~serc.titech.ac.jp
Program:
9:30 AM
Prof. Kasai will meet at the lobby of Tower Bldg., Hotel New Otani.
Walk from the Hotel to Nagata-Cho Station (7 mm.).
Take subway from Nagata-Cho to Nagatsuta Station (34 to 44mm.).
Take taxi from Nagatsuta Station to T.I.T. Campus (10 mm.).
10:50- 11:50
Presentations/Discussions on Engineering Seismnology*
12:00 - 13:00
Lunch Break (All Participants)
13:00 - 14:30
Presentations/Discussions on Engineering Seismology*
14:30 - 17:00
Presentations/Discussions on Passive Control**
17:00 - 17:30
Refreshments and Lab Tour by Prof. Kasal
18:00-
Dinner
and Entertainment ***
(Depending on the visitors’ availability)
*Engineeringg Seismology Topics:
Engineering Seismology in Kanto Basin Area and Others.
Numerical Simulation of tsunami Generation and Propagation.
Real-Time Seismic Hazard and Risk Assessment.
Micro-Zoning.
**Passive Control Topics:
Disp. Dependent Systems (Elasta-Plastic, Friction).
Velocity Dependent Systems (Visco-Elastic, Viscous).
Mixed Dependency Systems (Visco-Elasto-Plastic).
Unified Design and Performance Assessment of Various Systems.
Result of 2000 Passive Control Symposium.
Collaborations with Various Industry Groups.
Diner and Entertainment
Drs. Liu and Singh
Profs: Ohmachi, Midorikawa, Wada, Kasai