Volume 1, Number 5, February 2004

US-Japan Cooperative Structural Testing Research Program on Smart
Structural Systems

The Building Research Institute and the National Institute for Land and InfrastructureManagement, Japan and the U.S. National Science Foundation, in 1998 initiated a five-year
research and development project (1998-2003), "Smart Materials and Structural Systems". This
joint research is conducted under the auspices of the U.S-Japan Panel on Wind and Seismic
Effects of the U.S.-Japan Natural Resources (UJNR) Program. Smart Structural Systems aresystems that can automatically adjust their structural characteristics, in response to the change inexternal disturbance and environments, toward structural safety and serviceability as well as theelongation of structural service life. The joint research and development effort addressed thedevelopment and evaluation of: 1) performance evaluation methods of smart structure systems,2) health monitoring system, and 3) structural elements using smart materials. Findings from thisfive-year R&D project included: 1) rocking structural system that has auto-adaptive features(figure 1), 2) health monitoring system for an existing building and 3) semi-active isolation
systems using magnetorheological (MR) damper (figure 2). In the last year of the project three
Technology Utilizing Guidelines were published 1) Performance Evaluation Guideline of Smart
Structural Systems, 2) Technology Utilizing Guideline of Health Monitoring Systems, and 3)
Technology Utilizing Guideline on Effectors. These guidelines are written in Japanese (figure 3).
An English language abstract is underdevelopment and will be available at the BRI website(http://www.kenken.go.jp/english/contents/topics/structual/intelligence/main.htm).
The National Science Foundation has been actively funding research projects in smartsystems, structural health monitoring, and sensors.

Abase plateyieldsdue toA baseplateyields due
tensionofcolumn
to tension of column

Figure 1: Rocking structural system

Figure 2: Magnetorheological damper

Figure 3: Cover page of guidelines (in Japanese)

There are close collaborations between the US and Japanese colleagues in the area ofsmart structures. This partnership has been extremely productive and resulted in important
advances for both countries. One example is in the area of MR damper technology anddeployment. A project led by Prof. B.F. Spencer of the University of Illinois at Urbana-Champaign“Smart Damping Strategies for Seismic Protection of Urban Structures,” CMS-9900234, under theauspices of the US-Japan Urban Earthquake Disaster Mitigation Research Initiative, has focusedon the development of MR fluid dampers for protection of civil engineering structures. This project
has led to the commercial availability of large-scale MR dampers for civil engineering applications(e.g., the Lord Corporation in the USA and Sanwa-Tekki Corporation in Japan), and the world's
first full-scale implementations of these smart dampers in civil engineering structures. The firstfull-scale implementation of MR dampers was seen in the Nihon-Kagaku-Miraikan Building, anexhibition hall in the Tokyo Bay area designed by the Nikken Sekkei Corporation for futuristicscience and technology. Two 30-ton, MR Fluid dampers built by the Sanwa Tekki Corporationrdthusing Lord MR fluid are installed between the 3 and 5 floors (see Fig. 4 below). In China, thefirst full-scale smart damping control of cable stays will be implemented on the Dongting Lake
Bridge, located in Yueyang City, Hunan Province, China (see Fig. 5 below). This projectconstitutes the world's first full-scale implementation of smart damping strategies for mitigation ofstay-cable vibration on long-span bridges, and the world's first full-scale implementation ofmagnetorheological dampers for bridge structures. In 2004 the second building application wascompleted in Japan in the form of a “smart” base-isolated structure (see Fig. 6). The US-Japan
collaboration was essential in facilitating these projects and notable achievements.
The benefits of the research activities in Japan stress system applications and proof-ofconcept demonstrations; in the U.S. the focus is on enabling concepts and fundamental aspectsof the technological elements. Additional information on the joint research is available at:Contacts: Dr. Koichi Morita, Building Research Institute, morita@kenken.go.jp and Dr. Steven
McCabe, National Science Foundation, smccabe@nsf.gov.

Figure 4a. Nihon-Kagaku-Miraikan Building in Tokyo

Figure 4b. Installed MR dampers

Figure 5a. Dongting Lake Bridge in Yueyang City,
Hunan Province, China

Figure 5b. MR dampers on stays

Figure 6a. Base-isolated structure in Japan

Figure 6b. MR damper