Cyclone Mitigation Research in Australia and the U.S.
Queensland Florida
Global tropical cyclone tracks from 1985 to 2005
Daniel J. Smith Cyclone Testing Station, James Cook University Florida
*impact resistance windows
Hurricane Irma (tornado) Sept. 2017, Crescent Beach, FL Texas
Aged connections and poor maintenance
Hurricane Harvey (Cat. 4) August 2017, Holiday Beach, TX Queensland
Cyclone Debbie (Cat. 3) March 2017, Wilson Beach, QLD Aged connections and poor maintenance Cyclone Tracy (1974) Hurricane Andrew (1992)
• Peak gust estimated 243 km/h (71 Fatalities) • Peak gust estimated 281 km/h (65 Fatalities) • 70-90% of housing destroyed • >63,000 homes destroyed • Engineered structures performed better
Queensland Home Building Code (1982) Florida Building Code (2002) Building Codes for Wind Design (FL vs QLD) *Design of openings a key difference
Large negative pressure Negative pressure on roof at windward edge
Large Internal Positive positive Negative pressure pressures pressure on on wall lee wall Housing Performance (FL and QLD)
Financial loss ($) target ?
Life safety target
Traditional Life safety goals ? construction achieved Tomorrow Performance
Stronger building codes
Catastrophic cyclones Post-war era (Tracy and Andrew) construction
1940s To d ay Time Pre1980s Housing and Cyclones in Australia
Northern Territory Western 40%Australia Queensland 60% South Australia New South Wales
Population Victoria Australia 24 million Australian Tasmania Florida 21 million Capital Queensland 5 million Territory
Western AU. 3 million Credit: Australian Geographic Post 1980s design wind speeds in Florida vs Australia
240 km/h
. 258 km/h *converted assuming = 1.147 𝑉𝑉0 2 3 277 km/h 𝑉𝑉
295 km/h
314 km/h Australia • 1:500 Annual probability of exceedance • 10% in 50 yrs prob of exceedance
250 km/h
330 km/h 300 km/h
205 km/h
Florida (ASCE 7-10) • 1:700 Annual probability of exceedance 162 km/h • 7% in 50 yrs prob of exceedance Weather Stations in Queensland
~400 km
~100 km Weather Stations in Florida (Hurricane Irma)
~400 km
Florida = 170,000 km2 Far North Qld = 381,000 km2
*3-sec gust not corrected for terrain/instrument height
0.2-sec gust * (<129 km/h) (129-148 km/h) (149-166 km/h) (168-185 km/h) ~100 km (186-222 km/h) Surface Weather Information Relay and Logging Network (SWIRLnet)
R.M. Young wind monitor
Auger drill
Optional guying system
Data logger and telemetry 3.2 m
800 mm ground screw 1 m
Ground screw anchoring Vulnerability Models Key considerations 1. Wind data analysis 2. Post-event damage investigations 2. Experimental testing 3. Claims analysis All have pros/cons, all are needed to get the full picture
13 Post-event damage investigations
Pros clear picture of damage Cons no $ loss, time constraints, exterior view only sometimes
Metal roofing failure from TC Debbie (2017) Water ingress damage from TC Larry (2006) Experimental Testing
Pros specific connection strength and fatigue data Cons realistic simulation difficult (e.g., load sharing, aging)
Retrofit testing for roof to wall connections Roofing tile clip testing for wind uplift Typical damage modes
100% Roller Door Tree 80% Window Water Damage 60% Roof
40%
Likelihood of Occurrence Likelihood 20%
0% 0-10% 10-50% >=50% (157 Samples) (52 Samples) (26 Samples)
Limitations small sample sizes, more detailed analysis needed
www.jcu.edu.au/cts Vulnerability for Housing • Roofing, window, water ingress dominate loss • Minor damages independent of housing age (high frequency) • 1925-1981 housing at relatively > risk of structural damage • Modern housing still vulnerable • Solutions exist (e.g. tie down straps, shutters, etc.) Recommendations for Mitigation 1. Structural roof upgrading 2. Opening (i.e. windows, doors, etc.) protection upgrading 3. Community education/outreach
www.jcu.edu.au/cts Investing in Mitigation?
New Roof?
New Kitchen? 19 Understanding Behavior Change …we need to think bigger
Mitigation Prior experience capacity? with events?
Understanding Financial of risk? incentive?
The “hassle What is my factor” neighbor doing?
20 MultidisciplinaryThank and you! Collaborative