Flood Hazards and Flood Vulnerability Functions - … · Flood Hazards and Flood Vulnerability...
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Flood Hazards and Flood Vulnerability Functions Presentation to FHC Flood Standards Development Committee Christopher P. Jones, P.E. March 31, 2015 Tallahassee
Transcript of Flood Hazards and Flood Vulnerability Functions - … · Flood Hazards and Flood Vulnerability...
Flood Hazards and Flood Vulnerability Functions
Presentation to FHC Flood Standards Development Committee
Christopher P. Jones, P.E. March 31, 2015
Tallahassee
Flood Damage
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As in the case of wind, building damage due to flood depends on two things:
- Hazard Characteristics - Building Characteristics
Flood Damage
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As in the case of wind, building damage due to flood depends on two things:
- Hazard Characteristics - Building Characteristics
Flood Vulnerability Functions should account for both
Flood Damage
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As in the case of wind, building damage due to flood depends on two things:
- Hazard Characteristics - Building Characteristics
Flood damage usually accumulates from bottom up, wind from top down
What You Need to Know
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What gets wet?
What Gets Wet
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What You Need to Know
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What gets wet? Is the water moving rapidly?
Rapidly Moving Water
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What You Need to Know
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What gets wet? Is the water moving rapidly?
Does the ground erode/move?
Erosion and Scour
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Erosion and Scour
From Flood to Damage . . . .
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Flood Characteristics
Flood Loads
Building Characteristics (Flood Resistance)
Flood Damage
From Flood to Damage . . . .
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Flood Characteristics
Flood Loads
Building Characteristics (Flood Resistance)
Flood Damage
Vulnerability Functions
Flood Characteristics
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Flood Elevation/Depth Flood Velocity Wave Effects
Flood-Related Erosion/Scour Floodborne Debris Flood Duration
Floodwater (Fresh vs Salt; contamination)
Coastal Flooding:
(inundation, waves, velocity, erosion, debris, wind)
Riverine Flooding:
(inundation, duration, velocity, debris)
Riverine vs. Coastal Flood
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Flood Loads
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Hydrostatic (standing, slowly moving water)
Hydrodynamic (flowing water) Waves Debris
Hydrostatic Loads
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Hydrostatic Loads
Hydrodynamic Loads
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Hydrodynamic Loads
Photo courtesy of http://www.flickr.com/photos/colecamplese/
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Wave Loads
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(Next few slides show damage progression as wave crest rises from just below floor system to several feet above floor)
Wave Loads
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Sheathing on underside removed
Joists pushed landward
Wave Loads
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Wave Loads
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(Above: Landward side of house shown in previous slide. Right: looking up at landward wall)
Wave Loads
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Wave Damage Function
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Floodborne Debris Impact Loads
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Building Characteristics
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Lowest Floor Elevation Foundation Design Structure Design Flood-Resistant Materials Floodproofing/Mitigation
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Elevation
http://coastal.er.usgs.gov/hurricanes/coastal-change/images/eroded-duneLG.jpg
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View from beach (left) and road (right) of building before Hurricane Ivan, Orange Beach, AL
Foundation
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Foundation
Structure
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Structure (Importance of Connections)
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Materials
Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor
Flood Depth
Dam
age
Ratio
0
100%
Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor
Flood Depth
Dam
age
Ratio
0
100% Two Options: 1. Apply function to building
as a whole 2. Divide building into
assemblies, apply functions to each assembly • Assembly approach
facilitates combined flood and wind damage
Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor Several Sources (NFIP, USACE, Other)
Flood Vulnerability Functions
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Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor Several Sources (NFIP, USACE, Other) Frequently based on a mix of Damage
Surveys, Expert Opinion, Claims Data
Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor Several Sources (NFIP, USACE, Other) Frequently based on a mix of Damage
Surveys, Expert Opinion, Claims Data Residential and Non-Residential
Flood Vulnerability Functions
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Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor Several Sources (NFIP, USACE, Other) Frequently based on a mix of Damage
Surveys, Expert Opinion, Claims Data Residential and Non-Residential
Inundation and Wave Functions (use of other parameters more limited)
Inundation vs Wave
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Wave Damage
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Flood Velocity
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Flood Velocity
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Duration and Fresh vs Salt
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Erosion
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Flood Vulnerability Functions
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Typ. based on Flood Depth above Floor Several Sources (NFIP, USACE, Other) Frequently based on a mix of Damage
Surveys, Expert Opinion, Claims Data Residential and Non-Residential
Inundation and Wave Functions (use of other parameters more limited)
Often tied to Flood Zones on FIRM
NFIP FIRM
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Flood Hazard Zone(s)
• A Zones
• V Zones
• Coastal A Zones
Shown on the FIRM }
Used in Building Code, ASCE 7, 24, not shown on FIRM. LiMWA is shown.)
3-ft breaking wave 3-ft runup depth Wave overtopping
1.5-3 ft breaking wave
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Riverine and Coastal Waves < 3 ft
Coastal FIRM with LiMWA (establishes CAZ)
Limit of Moderate Wave Action
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Summary
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Flood Vulnerability depends on Flood and Building Characteristics
Key Points What gets wet Movement of water Erosion
Most Functions are tied to Flood Depth, with adjustments for other factors (waves, duration, salt vs fresh, velocity)
Expert Opinion, Damage Studies, Claims Data Combining Flood and Wind Damage
