Date: May 12, 2003
Place: National Institute for Land and Infrastructure Management, Tsukuba, Japan
Attendees: U.S.-side -- Enrique Matheu (Chairman) LSU
Anjana Chudgar USACE
Jon Ake USBR
Donald Yule USACE-EDRC
Japan-side -- Yoshikazu Yamaguchi (Chairman) PWRI
Akira Nakamura NILIM
Isao Nagayama PWRI
Takashi Sasaki PWRI
Hiroyuki Satoh PWRI
Ken-ichi Kanenawa PWRI
1. Objective and Scope of Work
To develop technical insights into better understanding of the response of dams to seismic effects, the T/C will plan, promote, and develop research initiatives to assist in assuring seismic safety and economical protective countermeasures against earthquake loading for these critical structures.
The scope of work includes:
(1) Develop methods of analysis for seismic design of dams including outlet works.
a) Comparative analysis of design methods and evaluation criteria used by U.S. and Japan.
b) Development of "Design Earthquake Ground Motions" for analysis and evaluation of dams.
c) Assessment of models and numerical procedures used for seismic dynamic analysis.
(2) Perform research to better understand the dynamic characteristics of dam construction materials and site conditions.
a) Strength and deformation characteristics of concrete, soil and rock materials during earthquakes.
(3) Evaluate observed performance of dams and outlet works during earthquakes.
a) Develop a database that contains measured ground accelerations and dynamic response of dams and outlet works during earthquakes, and other related information necessary to evaluate their seismic behavior, such as experimental and/or analytical data with description of test and analysis procedures used.
b) Investigation of damage mechanisms due to earthquake loading.
c) Application of the analysis of the observed dynamic behavior to the improvement of design criteria.
2. Accomplishments
(1) The Task Committee developed a database that contains measured ground accelerations and dynamic response of dams and outlet works during earthquakes. The database has been expanded to include other relevant information necessary to evaluate their seismic behavior, such as experimental and/or analytical data with description of test and analysis procedures used. Additional analysis modules have been implemented to facilitate processing of field test data.
(2) The Task Committee held the "3rd U.S.-Japan Workshop on Advanced Research on Earthquake Engineering for Dams", in San Diego, USA, on June 22-23, 2002. The workshop was part of the pre-conference activities of the 22nd USSD (U.S. Society on Dams) Annual Meeting and Conference, held at the same location on June 24-28, 2002. The workshop proceedings have been completed and they will be distributed in electronic and hardcopy formats by July 2003.
3. Future Plans
(1) The Task Committee will continue the current efforts focused on the development of improved mechanisms to facilitate the continuous exchange of results of research activities and general technical information related to dam earthquake engineering.
(2) The Task Committee will coordinate exchange visits of scientists and engineers from the U.S. and Japan. A series of case histories of mutual interest will be identified and prioritized and they will serve as the focus for this exchange program.
(3) The Task Committee will promote the development of joint research programs. The following topics have been identified as areas for future collaborative research:
a) Non-linear stress analysis of concrete dams:
The Task Committee will take advantage of the recent advances in this area achieved by the Japan side. The Task Committee will share the available analytical results, as well as experimental data collected during the shake table testing of a 1/20-scale model of a gravity dam conducted by the U.S. side.
b) Global stability analysis of concrete dams:
The Task Committee will conduct a review of the minimum requirements for sliding and overturning stability currently in use in the U.S. and Japan. The Task Committee recognizes the importance of this collaborative effort, as the corresponding guidelines will be subject to revision and update both in the U.S. and Japan.
c) Criteria for seismic analysis progression:
The Task Committee will review and compare the state of practice in the U.S. and Japan regarding current recommendations for progression of seismic analysis based on stages of increasing complexity.
Seismic evaluation of embankment dams:
The Task Committee will review criteria and guidelines for post-earthquake stability and deformation analysis of embankment dams.
The activities corresponding to the four areas indicated above will be addressed sequentially and the corresponding schedule will depend on the progress of the corresponding guidance documents, some of which are currently under discussion, development and/or review in the U.S. and Japan.
(4) The results of the joint research activities mentioned above will be reported as a series of joint papers to be submitted for presentation at recognized international conferences such as the WCEE (World Conference on Earthquake Engineering).
(6) Following large earthquakes in the US or Japan, the Task Committee will assemble a reconnaissance team to investigate the performance of dams and outlet works.
(7) The Task Committee will hold the "4th U.S.-Japan Workshop on Advanced Research on Earthquake Engineering for Dams" in the year 2004 in Japan. Specific location and time of the Workshop will be determined through correspondence between the Chairs of the Task Committee on Dams of the UJNR Panel on Wind and Seismic Effects.