SUMMARY, RESOLUTIONS AND RECOMMENDATIONS OF
THE THIRD JOINT TECHNICAL COORDINATING
COMMITTEE MEETING
-U.S.-JAPAN COOPERATIVE RESEARCH PROGRAM ON
SMART STRUCTURAL SYSTEMS (AUTOADAPTIVE MEDIA)-
The
Third Joint Technical Coordinating Committee (JTCC) Meeting of the U.S.-Japan
Cooperative Research Program on Smart Structural Systems (Autoadaptive Media Applied
to Civil Infrastructures) was held at the Building Research Institute (BRI) in
Tsukuba, Ibaraki, Japan on October 19, 2002. Fifteen U.S. and ten Japanese JTCC
members, plus 22 observers participated in the meeting.
The
Program is conducted by the U.S. National Science Foundation and BRI, Japan
under the aegis of the U.S.-Japan Panel on Wind and Seismic Effects of the U.S.-Japan
Cooperative Program on Natural Resources Development Program (UJNR).
Prior
to the third JTCC meeting, Workshop on Smart Structural Systems was held at the
Building Research Institute for U.S.-Japan Cooperative Research Programs on
Smart Structural Systems (Auto-adaptive Media) and Urban Seismic Disaster
Mitigation. Individual research findings were reported in the workshop.
In
the first part of the JTCC meeting, participants were separated into three
groups corresponding to three research thrusts: (1) structural systems, (2)
sensing and monitoring technology, and (3) effector technology. Research items,
plans and results in detail were discussed on the basis of presentations during
the workshop.
In
the second part of the JTCC meeting, a plenary session was held. Each working
group reported the summary of group discussion and the progress of research.
The series of large scale proof-of-concept experiments carried out by the
Japanese side were discussed in detail.
The
current U.S.-Japan Cooperative Research Program on Smart Structural Systems
(Autoadaptive Media Applied to Civil Infrastructures) will end at the end of
March, 2003, in Japan and summer, 2003, in the United States. In the concluding
session, desired research topics for future cooperation were discussed. The
following Resolutions and Recommendations were adopted.
The
three main thrusts of the research program on Autoadaptive Media are common for
the activities in Japan and in the U.S.A. It was noted, however, that the
activities in Japan have a primary emphasis on system applications and
proof-of-concept demonstrations while the activities in the US focus on
enabling concepts and fundamental aspects of the technological elements.
(1) The meeting was successful and fruitful for both countries and took
place in a cordial atmosphere. The participants are pleased to acknowledge the
excellent performance of the BRI staff in
preparing for and supporting the meeting.
(2) The reports of the working groups were accepted and their superb
progress and accomplishment to date were acknowledged.
(3) The series of large scale proof-of-concept experiments in Tsukuba,
Japan were critical for the proper development of autoadaptive media for
earthquake resistance of buildings.
(4) The bilateral cooperative research work including
short/long-term personnel exchange was successfully completed in the
large-scale tests conducted in Japan.
(5) The next JTCC meeting should be held in the US before April 2004.
(1) A structured means to facilitate and organize collaborative work
and create synergies between the US and Japan should be formalized, e.g., joint
funding mechanisms.
(2) The further discussion is needed for future research needs. The
following items were identified as possible subjects in the meeting;
1. Dense
instrumentation in infrastructure
2. Cooperation
between US and Japan on the basis of US NEES (George E. Brown, Jr. Network for
Earthquake Engineering Simulation) initiative and the use of E-defense shaking
table in Japan.
3.
Soil/foundation/structure interaction experiments, especially the comparative
study of test results of large-scale shaking table, small-shaking table, and
centrifuge tests with field tests.
SUMMARY OF GROUP SESSIONS
Participants of structural systems
Chairpersons: A.
WADA Tokyo
Institute of Technology
M.A.
SOZEN Purdue
University
Recorder: R.J.
FROSCH Purdue
University
Members: A.
K. AGRAWAL City
College of City University of New York
S. AIZAWA Takenaka
Co.
T.
AZUHATA BRI
M.
EBERHARD University
of Washington
H.
HIRAISHI Meiji
University
I.
M. IDRISS University
of California, Davis
J.O.
JIRSA University
of Texas, Austin
T.
KABAYASAWA University
of Tokyo
H.
KURAMOTO Toyohashi
University of Technology
E.
LOZINCA BRI
(Romania)
M.
MIDORIKAWA BRI
J.
PENZIEN ICE
Consultants
K.
SHIBA Shimizu
Corp.
Y.
TAKAHASHI BRI
K.
YOSHIMATSU Kumagaigumi
Corp.
A number of promising and novel applications for smart structural
systems were discussed. These
included autoadaptive structural systems with active or semi-active dampers and
rocking systems, reinforced concrete structural systems with passive dampers
and damage fuses, and innovative systems for life safety. Areas for current
research activities are summarized below.
(1) Two shaking table tests of multi-story steel frames provide
opportunities to test autoadaptive systems in large scale. A five-story frame was tested at BRI in 2001 to investigate rocking
systems. A three-story steel frame
was tested in Tsukuba in 2002 with six
different autoadaptive systems:
rocking systems, seismic-isolation systems with semi-active MR dampers,
response control systems with semi-active MR dampers, and damage control
systems with fuse elements (cementitious composites). New sensor technologies and
damage detection were tested as part of these
large-scale, shaking table tests.
(2) Performance-based design and assessment methods are being developed
for reinforced concrete structures with damage fuses. Selection of appropriate devices is underway. Practical methods and theoretical
formulas for evaluating responses of systems with various dampers are being
investigated.
(3) Engineers throughout Japan were surveyed to develop proposals for
innovative life safety systems for traditional light
construction. Analytical and
experimental investigations were carried out
for parallel linking of clusters of buildings. Shaking table tests of the parallel linking system were conducted during the summer of 2001.
(4) Eight theme structures (two structural steel and six reinforced
concrete) were selected for verifying smart structural systems. Analytical investigations are being conducted with these structures to compare
the response of standard frames, structures with base isolation and/or
structural control, and rocking systems.
Future collaboration between researchers in the US and Japan is encouraged
in two areas:
(1) The large-scale shaking table tests of the three-story steel frame during the spring and summer of 2002 provided a unique opportunity to test different
autoadaptive systems, monitoring systems, and effectors. US researchers are encouraged to take
advantage of the results from these tests.
(2) Collaborative research is necessary to facilitate the development
of design provisions so that smart structural systems can be used efficiently
by practicing engineers.
Incorporation of smart structural systems into the building inventory
has the potential for reducing life-cycle costs, improving the structural
performance after extreme events, extending the expected building life, and
expanding structural configurations, such as extremely long spans or very tall,
slender buildings, where traditional construction may not be possible. Reliable analytical techniques,
verified using large-scale laboratory tests of complete structural systems, are
needed to accomplish this goal.
II. Sensing and Monitoring
Technology
Chairpersons: Y.
Kitagawa and Sharon L. WOOD
Record: D.P.NEIKIRK
Members:
United States of America side
W.D.
IWAN Cal.
Tech
Genda
CHEN University
of Missouri-Rolla
A.M.SERECI Digitexx
Data Systems, Inc. Pasadena
Ming
L.WANG University
of Illinois, Chicago
Sharon
L. WOOD University
of Texas, Austin
Dean
P. NEIKIRK University
of Texas, Austin
Hian-Leng
Chan Stanford
University
S.C.
Liu NSF
Japan side
Yoshikazu
KITAGAWA Keio
University
Akira
MITA Keio
University
Takuji
HAMAMOTO Musashi
Institute of Technology
Shoichi
NAKAI Chiba
University
Masaomi
TESHIGAWARA Building
Research Institute
Takashi
KAMINOSONO National
Institute for Land and Infrastructure Management
Hiroshi
ISODA Building
Research Institute
Koichi
MORITA National
Institute for Land and Infrastructure Management
Kazuya
NOGUCHI National
Institute for Land and Infrastructure Management
Shunsuke
Otani University
of Tokyo
The purpose of Sensing and Monitoring Technology is to identify
research needs for developing new sensing systems, which consist of advanced
sensors and infrastructure for data collection, management, and interpretation.
Research is needed to develop new types of sensors and obtain information about
the long-term robustness of the sensors and data collection infrastructure. The
sensors and data collection infrastructure are important parts of smart
structural systems in buildings, which include sensors, effectors, and
processors.
Highly reliable monitoring systems that combine various advanced sensor
systems with system identification, performance assessment, and damage
diagnosis and prognosis techniques are required. The monitoring systems must be able to determine the extent
and location of damage for different types of structural systems. The information
should be made available in a form suitable for use by decision makers
immediately after an extreme event, as well as for pre-event and post-event assessment.
Researchers from Japan and the US made presentations about ongoing and
planned research. Specific topics
are listed below.
A. Sensor Technology
(US) Coaxial
Cables as Continuous Sensors for Health Monitoring of Civil Infrastructures
(US) Magnetoelastic Corrosion Sensing of Steel Cables
(US) Development
of Wireless Sensors to Detect Cracks in Welded Steel Construction
(US) Bond
Characterization Using Active Sensing Diagnostics
(JP) Summary
of activities of the Smart sensors working group (including RFID tag, wave,
temperature, and wire-saving sensors)
B. Monitoring and Damage Assessment
(JP) Damage
Detection Test Using Large Scale Test Frame
(JP) Story
Damage Detection of Multistory Buildings Using Natural Frequency Shifts of
Multiple Modes
(JP) Time-varying
Modal Identification of Damaged Structures by Monte Carlo Filter/Smoother
(JP) Development
of Health Monitoring System for an Existing Building
(US) Structural
Performance Evaluation Using Real-time Measurement of Hysteretic Behavior
(JP) Development
of Real-time Residual Seismic Capacity Evaluation System
(JP) Damage
Detection Using Support Vector Machine on Modal Frequency Patterns for a
Building Structure
(JP) Recent
Progress in Structural Health Monitoring of NEDO Smart Material/Structure
Program
C. Development of Sensor Networks
(US) Structural
Health Monitoring –A New Paradigm
(JP) Development of Sensor Network with RT-Linux
The Japan and US sides recognize the importance of cooperative research
that encourages progress in sensor technology, monitoring and damage
assessment, and networking. Exchange of existing data is critical for future
progress.
A summary report of the sensor and monitoring
component the five-year US-Japan cooperative program on smart structural
systems should be published before the next JTCC meeting.
A data repository should be established to
calibrate and validate damage detection models.
One or more demonstration projects should be
developed to evaluate new sensor technologies and sensor networks.
To assure and enhance cooperative effort in
this joint research program, exchange of researchers involved in both countries
is essential.
III. Effector technology
Chairpersons: T.
Fujita University
of Tokyo
B. F. Spencer, Jr.
University
of Illinois at
Urbana-Champaign
Record: H.
P. Gavin Duke
University
M. Iiba BRI
Members: S.
Soda Waseda
University
H. Fujitani BRI
N. Inoue BRI
H. Suwada NILIM
T.
Hiwatashi BRI
L. H. Weber NSF
H. Matamoros Univ.
of Kansas
G. Fischer Univ.
of Hawaii
9:00-9:05 Introduction
9:05-9:25 Presentation of
Japanese activities
(SMA, MR, Strain
induced material and Cementitious composites)
9:25-9:40 Presentation of
US activities
9:40-10:30
Discussion of collaboration works and contents of summary of the effector
technology.
The purpose of the effector technology research group is to develop
smart materials and smart devices and to verify that they can effectively
control the response of structures. Characteristics of smart materials and
devices will be investigated and reported. By relating their characteristics to
the applications, methods of implementing this technology will be evaluated
(e.g. suitable placement, required capacity, effective use, etc).
Through cooperative research in effector technologies in the US and
Japan, the exchange of knowledge and results is expected to be significant and
very useful to both countries in advancing this important technology.
(1) Various smart materials, such as shape memory alloys (SMA),
magneto-rheological (MR) fluids, piezoelectric and magnetostrictive elements,
and high performance fiber reinforced cementitious composites (HPFRCC) have
been selected as having high potential.
(2) Research progress and results achieved in 2000 to 2002 were
reported. Presentations on
effector technology demonstrated that significant progress has been made. Members of the research group are
encouraged by these achievements and by the potential for this technology to
increase structural performance and mitigate natural disasters.
(3) Research to-date has achieved the following:
a) Properties of SMA (Ni-Ti
alloy) bars were investigated. For application of SMA to structural usage, the
experiments on main bars of mortar beam,
bolted connection of steel beam-column joints, and bridge restrainers
were carried out.
b) MR fluids with improved
stability were developed and applied to MR dampers for practical
application. The validity of
various control methods for MR dampers were verified by conducting small and
large-scale shake-table tests for smart base-isolation and for story drift
control.
c) A field test of a PVDF
sensor was carried out, pointing out problems to be solved in future work. A fundamental study was made for semi-active
seismic isolation system using piezoelectric actuators.
d) US-Japan collaborative
work has been carried out on material and structural tests. Practical
applications of several types of HPFRCC are being investigated. Composite material performance has been
successfully translated into performance enhancement of structural components
and sub-systems.
Effectiveness of HPFRCC for damage control and auto-adaptive structural
response control has been demonstrated.
e) Large scale shaking table
tests on controllable base-isolation and story-drift control systems, using MR
dampers and controllable oil dampers, were carried out in 2002 through
collaborative efforts between the Japan-side (BRI-NIED) and the US-side (Duke
Univ.)
(1) Members of the effector technology research group will continue to
aggressively carry out research on this technology focused toward materials,
devices, and structural systems that are adaptive in order to demonstrate the
effectiveness of this technology for maintaining the functionality and
increasing the safety of structural systems, and disaster recovery. This technology will enable engineers
to control damage in structural systems and improve constructability.
(2) Research effort should concentrate on the following adaptive
materials and devices:
a) Shape memory alloys
b) Controllable fluids (e.g.
magneto-rheological fluids)
c) Induced Strain Actuators
d) High-performance fiber
reinforced cementitious composites (HPFRCC)
(3) Final Results and Future research plans for the current project are
as follows:
a) SMA devices for
residential construction will be improved and tested by using the
pseudo-dynamic test method.
b) The durability of the
magneto-rheological fluid as well as the damper should be verified for the
application to real buildings.
c) Semi-active seismic
isolation system using piezoelectric actuators will be studied in more detail
by simulation analysis.
d) Construction methods of
HPFRCC components and systems will be investigated. Research is also continued to examine the use of HPFRCC
devices in a smart structural system.
(4) It is recommended that future work continue in the assessment of
the applicability and efficacy of smart materials. Specifically:
a) Large-scale prototype and
components for autoadaptive devices and smart material components should be
developed and evaluated.
b) Evaluation should entail
large scale testing of devices on shaking table systems and with pseudo-dynamic
methods.
c) The results of testing
should be used to determine the dynamic mechanical properties of autoadaptive
devices and smart structural components and of the overall structural
performance of complete autoadaptive systems.
(5) Members of the effector
technology research group will vigorously exchange information and research
results. The research group strongly recommends and encourages the exchange of
researchers between the US and Japan.