Title: The ASCE 7 Tsunami Loads and Effects Design Standard for the U.S.

Author(s): Gary Chock

Publication: Symposium Paper

Volume: 313

Issue:

Appears on pages(s): 1-10

Keywords: tsunami, loads, design, codes, standards, ASCE 7, probabilistic, hazard, analysis, PTHA

DOI: 10.14359/51689684

Date: 3/1/2017

Abstract:
The Tsunami Loads and Effects Subcommittee of the ASCE/SEI 7 Standards Committee has developed a new Chapter 6 - Tsunami Loads and Effects for the 2016 edition of the ASCE 7 Standard, Minimum Design Loads for Buildings and Other Structures. Chapter 6 provides loads and other requirements for tsunami and its effects. The 2016 edition of the ASCE 7-16 Tsunami Loads and Effects chapter will be applicable initially to the states of Alaska, Washington, Oregon, California, and Hawaii, which are tsunami-prone regions that have probabilistically quantifiable hazards resulting from tsunamigenic earthquakes of subduction mechanism. The International Building Code (IBC) references design provisions that are given in American Society of Civil Engineers Standard 7. The ASCE 7 Standard becomes part of an enacted building code law through adoption of the model International Building Code by the local authority having jurisdiction (such as a state, county, or city). The IBC would incorporate ASCE 7-16 in 2018. Therefore, it is anticipated that the first national tsunami design provisions of ASCE 7-16 would be utilized as a part of mandatory building codes of U.S. jurisdictions after 2020. In these five western states, it is recognized by federal, state, and local governments that mitigation of tsunami risk to public safety requires emergency preparedness for evacuation, in addition to structural resilience of critical facilities necessary for immediate response and economic and social recovery. The public safety risk has been only partially mitigated through warning and preparedness of evacuation; there are many areas where complete evacuation cannot be assured. The lesson of recent catastrophic tsunami is that historical records alone do not provide a sufficient measure of the potential heights of future tsunamis. Engineering design must consider the occurrence of events greater than scenarios in the historical record, based on the underlying seismicity of subduction zones. For U.S. national tsunami design provisions to achieve a consistent reliability standard of structural performance for community resilience, Probabilistic Tsunami Hazard Analysis (PTHA) consistent with source seismicity is performed in addition to consideration of historical event scenarios.