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.