On November 17, 2017, ICLR conducted a Friday Forum webinar entitled 'Hurricane Irma damage assessment: Investigating the performance of Florida's homes during Hurricane Irma", led by Sarah Stevenson and Emilio Hong from Western University. In September 2017, Hurricane Irma impacted the island countries of the Caribbean before traversing the west coast of Florida. Following the storm, Western University students Sarah Stevenson and Emilio Hong travelled to Florida to assist researchers at the University of Florida with early assessments of the structural damage. This week-long investigation covered the Northern and Southwestern regions of the Florida Peninsula and involved house-by-house inspections in the hardest hit neighbourhoods. The Fulcrum app was used, with a custom damage survey form prepared by faculty at Auburn University, to record damage survey observations and store photos for each surveyed property. The goal of the investigation was to assess the state-wide performance of residential structures subjected to coastal wind, tornado, and/or storm surge hazards resulting from Hurricane Irma. In this webinar, Sarah and Emilio provided an overview of Hurricane Irma’s path and wind speed history, and discussed the survey methodology and tools, observed damage, and preliminary findings of the investigation. Sarah Stevenson is a PhD. student in Structural Engineering at Western University. Her research focuses on improving the hurricane resistance of residential structures in the Caribbean. Sarah recently completed her MESc. in Wind Engineering at Western. Her thesis research examined the behaviour of wood-frame roofs under extreme wind loads using data from past damage surveys and finite element modeling. Sarah has also participated in several post-storm assessments with Environment Canada, including surveying the damage from the Windsor, Ontario tornadoes in August, 2016. Emilio Hong is currently working as a Research Engineer at Western University. His work is part of a project studying the identification of tornadoes in Northern Ontario based on tree-fall patterns from aerial imagery. Emilio completed his MESc. in Wind Engineering at Western in 2017. His thesis research examined pressure coefficients on the walls of mid- and high-rise buildings. Emilio has participated in post-storm damage surveys, highlighted by the Angus, Ontario tornado of 2014, the Windsor, Ontario tornado of 2016, and the Quebec tornadoes of 2017.

1. Hurricane Irma Damage Assessment:
Investigating the performance of Florida’s homes during
Hurricane Irma
Sarah Stevenson, MESc., EIT
Emilio Hong, MESc.
Boundary Layer Wind Tunnel Laboratory
Western University
London, ON
ICLR Friday Forum
November 17, 2017

2. Overview
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• Hurricane Irma
• Path and Wind Speed History
• Impact
• Florida Damage Survey
• Survey Methodology
• Fulcrum App
• Survey Regions
• Observed Damage to Residential Structures
• Tornado Damage in Crescent Beach, FL
• Storm Surge and Wind Damage in SW Florida
• Summary and Lessons Learned

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September 5
September 10
September 3 August 31
August 30, 2017
September 11

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Source: National Weather Service (NWS)

5. Irma’s Impact in Florida
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• 75 total fatalities
• Florida: 11 fatalities (including 8 elderly persons
due to a nursing home air conditioning
malfunction)
• 116,000 people evacuated into 530 shelters
• Power loss affected up to 3 million customers
• Damage due to several tornadoes reported on
the East Coast
• Severe damage due to storm surge reported
along the Southern Coasts and the Keys

6. Impact in Florida
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Contour Map showing 3-second gust
wind speeds from Hurricane Irma

7. Impact in Florida
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Tornadoes confirmed by the
National Weather Service
Crescent
Beach, FL

8. Damage Assessment
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• Objective: To investigate the performance of
residential structures in regions experiencing
hurricane-force wind speeds
• The main focus was on single family homes,
including some mobile homes and multi-family
vacation rentals
• Survey Team:
• Faculty from the University of Florida (UF) and
Auburn University
• Graduate students from UF (5) and Western (2)
• UAV (drone) pilot

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• Approach:
• Walking surveys of
select neighborhoods
• Every structure in
each study area was
inspected – even
those with no visible
damage
• Fulcrum smartphone
app was used to
document surveys of
individual structures
St Augustine,
Marineland, &
Crescent Beach
Marco Island &
Goodland
Naples
Fort Myers
Everglades City &
Chokoloskee
Damage Assessment

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• Fulcrum App (www.fulcrum.com)
• App survey form developed based
on ATC-20
• The purpose of the form is to
provide consistent, detailed
evaluation procedures for engineers
and building inspectors
• Data was stored locally, then synced
to the Hurricane Irma database
• GPS coordinates link the damage
information to the location
Damage Assessment

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• Fulcrum App (www.fulcrum.com)
Damage Assessment

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• Tornado Damage
• Wind Damage
• Storm Surge
St Augustine,
Marineland, &
Crescent Beach
Marco Island &
Goodland
Naples
Fort Myers
Everglades City &
Chokoloskee
Damage Observations

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• Crescent Beach, FL
• Vacation townhome rentals, oldest buildings
constructed in 1982 – some had been rebuilt in
the 2000’s following a previous tornado
Tornado Damage

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• Crescent Beach, FL
Tornado Damage

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Tornado Damage
• Estimated wind speed: 130 mph
• Design wind speed: 132 mph
• Previous design wind speed (2005): 121 mph

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Tornado Damage
Wall top plate
Roof rafters
Hurricane tie

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• Vilano Beach, FL
• Storm surge height up to 6 feet measured
nearby (USGS data)
Coastal Failures

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• Vilano Beach, FL
Coastal Failures

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• Marco Island
• Goodland
• Chokoloskee
• Everglades City
• Port Charlotte
• Fort Myers
• East Naples Marco Island &
Goodland
Naples
Fort Myers
Everglades City &
Chokoloskee
Southwestern Florida

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• Consistent, minor
damage observed over
large residential areas
• 215 Structures Surveyed
• Minor damage to clay tile
and asphalt roofing was
common
Marco Island

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• Estimated wind speed: 108 mph
• Design wind speed: 170 mph
• Previous design wind speed (2005): 137 mph
Marco Island

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Goodland
• Estimated wind speed: 108 mph
• Design wind speed: 170 mph
• Previous design wind speed (2005): 137 mph

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Goodland

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Chokoloskee

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Everglades City

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Everglades City

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Everglades City

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• Insurance Institute for Business and Home
Safety (IBHS) FORTIFIED Homes™
• https://disastersafety.org/fortified/fortified-home/
• Inspected and compared to neighboring homes to
assess relative performance
• Minor roof cover damage
• Comparable levels
of damage in
FORTIFIED and
other nearby homes
Port Charlotte & Fort Myers

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• Estimated wind speed: 100 mph
• Design wind speed: 166 mph
Naples
Single Family,
Wood-Frame Homes
Mobile Home Park

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Naples

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Naples

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Naples

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• Damage was generally minor, but widespread
across the state
• Tornado, storm surge and wind damage in the
Northeast
• Storm surge and wind damage in the Southwest
• Severe damage occurred in isolated cases
• Maximum recorded gusts were below current
design wind speeds
• Difference in design speeds for older homes could
have contributed to observed wind damage
Summary of Observations

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• Storm surge damage caused significant losses
• Newer, elevated homes performed well
• Extent of interior
damage was not
generally assessed,
unless homeowner
was present
Summary of Observations

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• Hurricanes bring a number of hazards in
addition to wind - often act in combination
• Identification of different structure types by
external inspection - attention to details
• It is important to collect a representative
dataset - not just the dramatic failures
• Adaptability
• Be prepared (bottled water, power banks for
phones, cameras, sunscreen, etc.) but pack as
light as possible
Things We Learned

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We wish to extend our sincere thanks to:
• Institute for Catastrophic Loss Reduction
• The University of Florida team:
• Dr. David Prevatt
• Dr. Kurt Gurley
• Jack, Rodrigo, Jason,
Karthik, Andreas
• Dr. David Roueche
• Kwasi Perry
The team also wishes to acknowledge the financial
support of the Florida Building Commission, and the
National Science Foundation RAPID Award through
Notre Dame University

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Thank you for your time!