Reliability Bases for Tornado Load Criteria for ASCE Standard 7-22
Publication: Journal of Structural Engineering
Volume 150, Issue 11
Abstract
Tornadoes are intense localized convective windstorms that are among the most devastating natural hazards that occur in the United States. Although the probability of any tornado striking one particular building in any given year is quite low because of its small footprint, when strong tornadoes strike densely populated areas, the results can be catastrophic; the Joplin, MO tornado of 2011 caused 161 fatalities and nearly $3 billion in damages. Such losses are projected to increase in the future as a result of urbanization and economic development. ASCE Standard 7-22 on Minimum Design Loads has, for the first time, included new reliability-based design criteria for tornado loads. The objective of this paper is to provide archival documentation of the basis for these tornado-resistant load provisions in Chapter 32 of ASCE 7-22. This paper summarizes the significant challenges that were overcome in addressing the fundamental differences between effects of tornado and nontornadic winds and the higher uncertainties associated with tornado wind pressures that must be accommodated in the risk-informed framework of ASCE 7-22. These challenges were addressed through reliability analyses that led to new tornado load criteria that provide reasonable consistency with the reliability delivered by existing criteria for nontornadic winds.
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Data Availability Statement
Some or all of the data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request.
Acknowledgments
Support for the development of tornado-resistant design criteria for ASCE 7-22 was provided in part by the US National Institute of Science and Technology (NIST). The views expressed herein are those of the authors and may not represent the official positions of NIST or the American Society of Civil Engineers. The authors thank members of the ASCE 7 Tornado Reliability Working Group—James R. Harris, Therese P. McAllister, Don Scott, and Lawrence Twisdale—for their advice and are especially grateful for the guidance provided by Marc Levitan of NIST during the study. The reliability calculations summarized herein were also performed independently by Abdullah Braik, Texas A&M University.
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Published In
Journal of Structural Engineering
Volume 150 • Issue 11 • November 2024
Copyright
© 2024 American Society of Civil Engineers.
History
Received: Nov 27, 2023
Accepted: Jun 6, 2024
Published online: Aug 29, 2024
Published in print: Nov 1, 2024
Discussion open until: Jan 29, 2025
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