Newswise — Reston, Va.—The first of seven post-disaster assessment teams assembled by the American Society of Civil Engineers deployed last weekend to Japan to study the effects of the March 11, 2011, 9.0 magnitude earthquake and resulting tsunami which wrought destruction along that nation’s Pacific coastline. The tsunami inundated approximately 292 square miles, or 470 square kilometers.
As an essential source of technical standards, ASCE provides a vital service to the civil engineering profession. The ASCE 7 Standard governs the Minimum Design Loads (weights) for Buildings and Other Structures. Currently, all coastal flood minimum design standards for buildings and other structures are based on hurricane conditions, and these have never been evaluated for tsunami-wave conditions. Fluid and impact loads and scouring from tsunami inundation poses a significant threat to coastal buildings and infrastructure.
According to the Oregon Department of Geology and Mineral Industries, this event is virtually a mirror image of what might occur whenever the next major earthquake occurs on the Cascadia Subduction Zone off our West Coast. Inundation of the Washington, Oregon and northern California coastlines could occur within 15 minutes of such an earthquake. There is a population of 13 million west of the Cascade Range. Because of the industrialized and densely populated nature of the Honshu Tohoku coastline, and the similarities between Japanese and U.S. building codes, lessons from this tsunami will be immediately relevant to the U.S. West Coast, Alaska, Hawaii, and Canada.
The purpose of this first team’s reconnaissance trip will be to document the performance of buildings and other structures in Miyagi and Iwate prefectures along the Tohoku coastline of Japan, with a specific focus on how their findings can be incorporated into the tsunami structural design provisions under development for the next revision of the ASCE 7 Standard. This field reconnaissance will help resolve some key questions in the tsunami design provisions regarding flow velocities and momentum of tsunami surges over land, debris flow, debris strike effects, and scouring, as well as provide information on overarching questions on risk-based design criteria and the ultimate abilities of structures to resist a maximum credible tsunami.
ASCE has established a committee for its 2016 update of its ASCE 7 Standard to discuss Performance-Based Tsunami Engineering for Coastal Structures. Thus, the knowledge to be gained by this damage assessment will directly improve ASCE’s ability to influence international codes and standards related to civil engineering. Conducting the reconnaissance of this benchmark event will directly impact U.S. capability to exercise technical leadership in this field.
The team is posting its daily findings on the ASCE website, including photos. See it at http://www.asce.org/PPLContent.aspx?id=12884906227.
Tsunami Effects Team Leader:Gary Chock, MS.C.E. P.E., Martin & Chock, Inc., Honolulu, Hawaii
Other Tsunami Team Members:David Kriebel, Ph.D., P.E., U.S. Naval Academy Dept. of Naval Architecture & Ocean Engineering, Annapolis, Md.
Ian Robertson, Ph.D., P.E., Structural Engineer, University of Hawaii, Honolulu, Hawaii
Ioan Nistor, Ph.D., P.E., University of Ottawa
Matthew Francis, P.E., Senior Geotechnical Engineer, URS Corporation, Salt Lake City, UT
Daniel T. Cox, Ph.D., Past Director, O.H. Hinsdale Wave Research Laboratory, Oregon State University
As part of its disaster response procedure, ASCE forms technical teams to study infrastructure damage caused by natural or man-made disasters. Such studies are conducted so that engineers may learn from the disaster, and that those lessons learned may be documented to inform future actions.
ASCE has participated in more than a dozen disaster assessments in the last decade, including studies of the World Trade Center and Pentagon in 2001; assessments following hurricanes Katrina and Ike; tsunami assessments throughout the Indian Ocean Basin in 2004 and at the Samoa Islands; and earthquake assessments in China, Peru, Japan, Sumatra-Andaman, Alaska, California, Italy, Algeria, Turkey, Haiti and Chile.
Founded in 1852, the American Society of Civil Engineers represents more than 140,000 civil engineers worldwide and is America’s oldest national engineering society. For more information, visit www.asce.org.