Joplin, Missouri, Tornado of May 22, 2011

63 Pages·2012·5.747 MB·English

by  David O. Prevatt, William Coulbourne, Andrew J. Graettinger, Shiling Pei, Rakesh Gupta, David Grau

Joplin, Missouri, Tornado
of May 22, 2011

Structural Damage Survey and Case for
Tornado-Resilient Building Codes

David O. Prevatt, Ph.D., P.E.
William Coulbourne, P.E.
Andrew J. Graettinger, Ph.D.
Shiling Pei, Ph.D., P.E.
Rakesh Gupta, Ph.D.
David Grau, Ph.D.

Published by the American Society of Civil Engineers
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Contents

Preface ................................................................................................................... v
Acknowledgments ............................................................................................................ vii
Chapter 1 Joplin Tornado Overview ........................................................................... 1
Chapter 2 Inspection Methodology ............................................................................. 5
Chapter 3 Residential Building Performance ........................................................... 16
Chapter 4 Performance of Commercial Buildings and Critical Facilities .................. 24
Chapter 5 Joplin and a New Tornado Design Philosophy ........................................ 36
Chapter 6 Proposed Tornado Load Commentary for ASCE 7 ................................. 40
Chapter 7 Conclusions and Recommendations ....................................................... 46
References ................................................................................................................. 49
Index ................................................................................................................. 53
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Preface

This report presents observations, findings, and recommendations from an engineering
reconnaissance trip following the May 22, 2011, tornado in Joplin, Missouri. A team of building
and construction professionals experienced at high-wind damage investigation was tasked with
investigating and documenting the performance of residences and critical buildings [International
Building Code (IBC) Occupancy Category II, III, and IV] in Joplin. The Enhanced Fujita (EF) Scale
5 tornado created a 7-mile-long damage swath, destroying over 5,000 buildings in the process
and killing over 150 people. The total economic loss from this single event was nearly 25% of the
total loss caused by the 1,400 tornadoes that were reported during Spring 2011. The Joplin
tornado occurred just one month after another tornado devastated Tuscaloosa, Alabama, and
together these events caused over $13 billion in economic losses, or approximately 3% of the
combined annual Gross Domestic Product (GDP) of the two states.

The primary objective of this data collection exercise was to gather information to enable
better understanding of predominant structural failure mechanisms associated with tornadic wind
loads. The data and recommendations are presented so that they will be used to support future
development and/or modification of building design guidelines and standards. While mortality
rates in tornado events have been relatively stable, building damage and overall economic losses
continue to grow, perhaps due to greater populations living in tornado-prone regions. Tornado
damage is particularly extensive when tornadoes impact medium- to large-sized cities with dense
concentrations of buildings. There are building design guides in use today by the engineering
profession that may mitigate damaging effects from more moderate (EF0 to EF2) tornadic winds.
New ways are needed to improve the general level of engineering and construction for residential
structures. In addition, revision of structural retrofit practices should be considered for mitigating
future losses from tornadoes. The findings from the field study are instrumental in validating
recent results on tornado loads from laboratory experiments and numerical analyses.

On May 29, 2011, the reconnaissance team arrived in Joplin and was briefed by Federal
Emergency Management Agency (FEMA) personnel, city officials, and local structural engineers.
In a series of transects perpendicular to the tornado’s path, the team observed a gradual
reduction in severity of damage from the center of the path towards the edges. Case studies are
presented to illustrate common damage patterns and this reduction in damage severity. Many
failures were attributed to the lack of continuous vertical and/or lateral load paths, not just to wind
speeds that exceeded building code levels. The study team found numerous examples of load-
path failures where detailing in compliance with current building codes for hurricane-prone
regions would have reduced the damage and potentially reduced injuries.

The findings of the damage assessment team are based on their five days surveying
damaged homes, critical facilities, and schools in Joplin. The team used a data collection
methodology that documented damage and assigned failure mechanisms to over 150 buildings.
The data was collated every day and logged in electronic and hardcopy forms. The team
received partial travel support from the American Society of Civil Engineers/Structural
Engineering Institute, and it was composed of structural engineers (consultants and academics),
wood scientists, and civil engineering students. A blog site was created
(http://www.davidoprevatt.com/joplintornadoblog) and used to disseminate the team’s preliminary
findings at the end of each day’s investigation.
This report is divided into six chapters. Chapter 1 presents an overview of the tornado
and its formation and passage across the City of Joplin, as well as summary details of the
demographics of the building stock. A description of the data collection methodology used is
presented in Chapter 2. Chapter 3 presents detailed findings and descriptions of the damage
observed in residential construction, and Chapter 4 presents observed damage in the commercial
(engineered) structures and critical facilities. Chapter 5 presents a discussion of the damage in
relation to the Enhanced Fujita Scale. Finally, in Chapter 6, summary conclusions and
recommendations for the direction of further studies to develop guidelines for tornado-resilient
construction are provided.

Disclaimer
The opinions and views expressed by the authors in this report are theirs alone and do not
represent the views of any funding agencies. All information in this report is believed by the
authors to be factually correct, but readers should use any information contained herein at their
own risk.

David O. Prevatt, Ph.D., P.E., University of Florida, Gainesville, FL
William Coulbourne, P.E., Applied Technology Council, Washington D.C.
Andrew J. Graettinger, Ph.D., University of Alabama, Tuscaloosa, AL
Shiling Pei, Ph.D., P.E., South Dakota State University, Brookings, SD
Rakesh Gupta, Ph.D., Oregon State University, Corvallis, OR
David Grau, Ph.D., University of Alabama, Tuscaloosa, AL
Acknowledgments

The authors would like to acknowledge the American Society of Civil Engineers/Structural
Engineering Institute for their support of this project. The participation of Drs. John van de Lindt
and Jim Richardson of the University of Alabama, Mr. Bryan Wert and Mr. Sam Hensen of
Simpson Strong Tie, and Dr. Arijit Sinha of Oregon State University is acknowledged. The
support of the University of Florida Engineering School for Sustainable Infrastructure and the
Environment and the Applied Technology Council is also acknowledged. In addition, we are very
appreciative of the efforts provided by two local structural engineers, Mr. John Miller and Mr. Ben
Jennings of J&M Engineering, Springfield, Missouri, who assisted with the data collection
exercise and by providing valuable local insight on past and present construction practices in
Joplin. In addition, Mr. Miller along with Mr. Bob Paullus of Paullus Structural Consultants of
Olive Branch, Mississippi, provided insightful comments in their reviews of the final manuscript.
The content of this report solely reflects the views of the authors and not the American Society of
Civil Engineers.

The damage assessment team would like to acknowledge the logistical support provided
by Ms. Wesley Parker, FEMA’s Mitigation Branch Chief of the Joint Field Office; Mr. Scott Cope,
City of Joplin Building Code and Enforcement Supervisor; and support of the FEMA Headquarters
Office staff that coordinated daily briefings and provided other valuable information.

The following students from the participating universities are also acknowledged for their
valuable contributions to this work:

University of Florida: Mr. David B. Roueche
The University of Alabama: Mr. William (Blake) Doherty
Mr. Lane Morrison,
Mr. Alireza Geranmayeh
South Dakota State University: Mr. Jordan Paul
Oregon State University: Ms. Kathryn Pfretzschner
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Chapter 1
Joplin Tornado Overview

On Sunday, May 22, 2011, the deadliest U.S. tornado in more than 60 years touched
down in the southwestern Missouri city of Joplin (Green and AP 2011). The tornado was part of a
larger severe weather system that spawned tornadoes and severe weather across the Midwest.
At 1:40 PM, due to the existence of conditions that were favorable to the development of
tornadoes, the National Weather Service (NWS) issued a tornado watch for the Joplin and the
surrounding areas. Less than four hours later, at 5:17 PM, the NWS issued a tornado warning
based on Doppler radar indications for Joplin and Jasper County, Missouri (CNN 2011).
Residents were urged to seek shelter in a safe location in preparation for the tornado as tornado
sirens sounded throughout the city. However, due to the timing of the storm, many people were
outside of their homes engaged in other activities and the events that had been planned for the
day. In fact, Joplin High School’s graduation had just concluded at Missouri Southern State
University in northeast Joplin when the tornado touched down at 5:41 PM (CNN 2011).

The City of Joplin has a population of approximately 50,000 and is primarily made up of
single-story single-family homes, small apartment complexes, and light commercial structures.
The tornado cut a damage path directly through the center of the city, damaging many of these
residential and commercial areas, along with schools, churches, and other institutional structures.
St. John’s Regional Medical Center, one of the city’s two major hospitals, took a direct hit from
the tornado while 183 people were inside, killing five (Heintzelman and KSHB-TV 2011). In total,
the tornado killed nearly 160 people and injured more than 1,000.

Numerous tornadoes were reported around the Midwest on May 22nd. As shown in
Figure 1.1, a probabilistic tornado graphic, which indicated a 10% probability of a tornado strike
for the City of Joplin, was issued for a large portion of the country on and prior to May 22nd. The
supercell thunderstorm that produced the Joplin tornado rapidly formed and strengthened in the
extreme southeastern corner of Kansas just over an hour before the tornado touched down in
Joplin. At 5:08 PM, NWS storm spotters reported multiple funnel clouds in Cherokee County,
Kansas (News Mappers 2011).

The Joplin tornado traveled on the ground for over 22 miles. The damage path began
southwest of the intersection of JJ Highway and West 32nd St. in Joplin and traveled northeast,
then southeast to the end of the damage path approximately 4.8 miles northeast of Granby,
Missouri. Although the tornado was on the ground for over 22 miles, it only sustained a violent
intensity for approximately 6 miles with a width of approximately ¾ of a mile (NOAA 2011). The
tornado path cut across Jasper County and the study area as shown on the locator maps in
Figure 1.2. The City of Joplin was in the direct path and was bisected in a west–to-east direction
as shown in Figure 1.3, affecting the major east-west roads including 32nd St., 20th St., and
Interstate 44. The major north-south roads impacted were Schifferdecker Ave., Main St., and
Rangeline Road. The tornado path, outlined by a dashed red line in Figure 1.3, was determined
from aerial photography and ground verification. The length of the study area is approximately 6
miles and runs from west of Schifferdecker Ave. to Kenser Road on the east.