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Post 2004 Hurricane Field Survey Evaluation of the Relative Performance of the Standard Building Code and the Florida Building Code. Kurt Gurley – UF Jeff Burton – IBHS Makola Abdullah – FAMU Forrest Masters – FIU Tim Reinhold – IBHS. Project Goal.
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Post 2004 Hurricane Field Survey Evaluation of the Relative Performance of the Standard Building Code and the Florida Building Code Kurt Gurley – UF Jeff Burton – IBHS Makola Abdullah – FAMU Forrest Masters – FIU Tim Reinhold – IBHS
Project Goal • Determine if 2002 code change reduced the vulnerability of residential single family homes • Quantitative rather then anecdotal • Physical damage • $ Loss ratio • Behaviors (mitigation & evacuation) • Stratify results by wind speed and code
Additional Objectives • Include and contrast structures in each of the areas impacted by 2004 storms • Subject targets – site built single family • Post Andrew, pre-Florida Building Code • 1994 – 2001 (‘old’) • Post Florida Building Code • 2002 – 2004 (‘new’)
Methodology • Pre-arranged appointments with randomly selected homeowners to gather damage information • Interview homeowner • Inspect property • Prior knowledge of • home details ( Yr of construction, Roof / Wall type, etc.) • home location relative to peak 3-second wind speeds • NO prior knowledge of damage • no visual bias to sample selection • to determine ‘average’ damage and $ loss
Tools • Access to wind swath maps • Vickery: Applied Research Associates • Powell: NOAA • Access to county databases: • Home location • Homeowner • Year of construction • Roof cover (asphalt, tile) • Roof type (hipped, gable) • Wall type (masonry, wood frame) • Appraised value pre-2004 storm season
Wind Swath Maps • Charley • Ivan • Frances • Jeanne
GIS Database - Charlotte County • All Single family units 2002 - 2004 ‘new’
GIS Database – Stratifications • ‘old’ units with tile roofs – Punta Gorda Isles
Stratified Sampling Procedure • Overlay wind swath maps with homes that fit desired characteristics (age, roof cover, etc.) • Randomly select homes across desired wind swath contours • The homeowners contacted by phone in random order (25% success rate)
Survey Details: Inspection • Digital photograph s • All angles and corners of subject • Surrounding terrain • Distance to adjacent large objects in all directions • Sketch elevations and plan view
Survey Details: Inspection • Attic inspection • Sheathing type and thickness • Sheathing nail size, edge and field spacing • Gable end bracing • Roof to wall strap installation • Garage inspection • Pressure rating, bracing • Location, size and type of every window and door • includes protection details & damage
Survey Details: Interview • Evacuation behavior • Mitigation behavior (shutters) • Indicate damage on elevation sketches • Water penetration • Roof cover failure • Soffit failure • Window and / or shutter failure • Scan any damage pictures • Insurance reimbursement information
Survey Details: Interview • Data entered directly into • handheld PDA • Upload to access database
Charley Surveyed Homes Charley 126 Surveyed Homes 2002-2004 1994-2001 3-Sec Gust (MPH)
Frances and Jeanne Frances & Jeanne 33 Surveyed Homes 2002-2004 1994-2001 3-Sec Gust (MPH)
Ivan Surveyed Homes Ivan 36 Surveyed Homes 2002-2004 1994-2001 3-Sec Gust (MPH)
Water Penetration: Charley (All) New Old
Water Penetration: Charley (11) New Old
Water Penetration: All stormsZone 8 (110 – 120 mph 3 sec. gust) New Old
Water PenetrationResults Summary • Water penetration by code: • It is not clear from the study that the FBC provides improvement in preventing water penetration. • 1994 – 1998 more likely to have ceiling damage
Window Protection: 2004 and Future Use Window protection use in 2004 and future storms New Old
Window ProtectionResults Summary • Mitigation effectiveness – shutter use: • A significant percentage (3 - 4%) of unprotected windows were damaged in the highest wind zone (140 – 150 mph) in Charley, while protected windows experienced significantly less damage. • At the lower wind zone 8 (110 – 120 mph gust), protected windows permitted almost no damage, while the percentage of damaged unprotected windows was small but consistent among storms.
Soffit DamageResults Summary • Soffit performance with age of construction: • Increased likelihood of soffit damage with increasing age of structure (over the surveyed range 1994 – 2004).
Roof Cover - TileResults Summary • Tile roof cover performance: • Few surveyed tile roof homes of any age group had no cover damage • Higher probability of field tile loss in ’94 – ‘01 homes compared to new construction • 2002 – 2004 • 15% had tile damage exceeding 5%, (mostly ridge cap loss) • 1999 – 2001 • 60% had over 5% damage • 44% over 10% damage • 22% over 25% damage • 1994 – 1998 • 60% had 6-25% damage
Roof Cover - Shingle Results Summary • Shingle roof cover performance by age of construction: • For highest wind zone 140 - 150 • Distinct difference in shingle performance by age • 1994 - 1998 significant quantities of shingle damage • 1999 – 2001 less damage • 2002 – 2004 small quantity of damage on average • 1994 – 1998 Every shingle house surveyed in zone 11 had shingle damage, all had at least 10% shingle loss, and most had between 25 and 50% loss. • 2002 – 2004 30% of shingled houses had no shingle damage, and the wide majority of those that had damage lost less than 5 % of their shingles.
Roof Cover - ShingleResults Summary • Shingle roof cover performance by wind speed: • Charlotte County • 110 – 120 mph : 32% of homes had shingle damage • 130 – 140 mph : 65% • 140 – 150 mph : 79%
Roof Cover - Shingle Results Summary • Shingle roof cover performance by region: • 110 – 120 mph 3 sec. gust • Charlotte County (32% of homes damaged) • St. Lucie County (80%) • Escambia County (50%) • Charlotte County suffered less quantity of damage on average than those in the Ivan and Frances / Jeanne regions.
Concluding Remarks • Major findings • Demonstrate: • Effectiveness of window protection • Improvement in shingle performance • Tile: older more likely to experience field tile damage • Some aging effects on roof cover performance • Support efforts to improve: • Water Intrusion standards • Tile roof cover installation standards • Ridge cap installation standards • Soffit installation standards