Nursery Cyclone Presentation June 2013

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  1. 1. Cam Leitch Shane Holborn Designing structures to manage high wind loads
  2. 2. Presentation summary Background to the project Cyclones Designing to withstand extreme wind Risk levels and wind speed Cyclone Yasi overview of field data and observations Critical factors for structural performance Recommended good practice details
  3. 3. Mission is to: Conduct quality research and testingConduct quality research and testing (Leads to(Leads to better materials andbetter materials and building practices)building practices) Community education a research & community educationCommunity education a research & community education program to improve the resilience of housing to severe winds.program to improve the resilience of housing to severe winds. Damage Investigations following severe wind events Damage Investigations following severe wind events essential to investigate both undamaged buildings thatessential to investigate both undamaged buildings that performed well, buildings that suffered damage (how & why?)performed well, buildings that suffered damage (how & why?) and to see if measures are needed for improvements orand to see if measures are needed for improvements or changes to construction details.changes to construction details. Vision - ToVision - To minimise loss and suffering as a result ofminimise loss and suffering as a result of severe wind eventssevere wind events Cyclone Testing Station James Cook Uni
  4. 4. Static or cyclic loadingStatic or cyclic loading ofof roofing, wall cladding,roofing, wall cladding, structural elements, joints, complete structuresstructural elements, joints, complete structures UUplift, racking, flexure, pressure,plift, racking, flexure, pressure, wind drivenwind driven debrisdebris impactimpact Wind tunnel studiesWind tunnel studies Risk assessmentRisk assessment Testing and consulting for industry; Cyclone Testing Station
  5. 5. Previous Cyclones in Queensland (Winifred 1986)
  6. 6. Cyclone Larry 2006
  7. 7. Larry made landfall close to Innisfail on 20 March 2006 Just prior to landfall, reported asJust prior to landfall, reported as a Category 5 by BoMa Category 5 by BoM Wind gusts reaching 240 kilometres per hour Traveling W NW at ~ 30 kphTraveling W NW at ~ 30 kph Estimted $1.5 billion damage. The costliest tropical cyclone to ever impact Australia surpassing Cyclone Tracy (1974). Cyclone Larry - 2006
  8. 8. Cyclone Ului - 2010 Fluctuated in intensity Weakened to category 2 before regaining category 3 strength. 21st March crossed the outlying Whitsunday Islands and made landfall at Airlie Beach, Queensland. Damage $20 million and agricultural losses reached A$60 million.
  9. 9. Cyclone Yasi - 2011
  10. 10. Made landfall in northern Queensland, Australia in the early hours of 3 February, 2011, causing severe damage to affected areas The eye crossed the coastline at Mission Beach just before midnight and passed over Tully soon after. The storm caused an estimated US$3.6 billion in damage, making it the costliest tropical cyclone to hit Australia on record Cyclone Yasi - 2011
  11. 11. Wind speed estimated from numerical models, street sign data and the occasional Anemometer 5 1 0 1 5 1 5 1 5 2 0 2 0 2 0 2 0 2 0 2 5 2 5 2 5 3 0 3 0 3 0 3 5 3 5 3 5 4 0 4 0 4 5 4 5 5 0 5 0 5 5 6 0 6 5 7 0 7 5 C a i r n s C a r d w e l l T o w n s v i l l e C l u m p P o i n t J e t t y L u c i n d a a i r n s A M O I n g h a m T o w n s v i l l e A M O G r e e n I s C a i r n s A P A I M S O R P H E U S I S F l y i n g F i s h P o i n t E t t y B a y W o n g a l i n g B e a c h S o u t h M i s s i o n B e a c h T u l l y H e a d s S o u t h J o h n s t o n e B a b i n d a I n n i s f a i l M o u r i l y a n K u r r i m i n e B e a c h B i n g i l B a y E l A r i s h S i l k w o o d T u l l y M o u r i l y a n H a r b o u r C o w l e y B e a c h M i s s i o n B e a c h B r a m s t o n B e a c h M i r r i w i n n i G o r d o n v a l e Recording wind speed in tropical cyclones
  12. 12. Max upper bound gust speed ~240 km/h ~67 m/s Design wind speed houses 250 km/h ~ 69 m/s Max upper bound gust ~95% design speed Cardwell, Tully Heads, South Mission Beach Max upper bound gust ~85% design speed Tully, Kurrimine Beach Low Cat 4 wind speeds (mainland) - issue with what the affected community thinks went through complacency in builders and home owners for possible future events Yasi Estimated Wind Speeds
  13. 13. The Gap Super Cell Brisbane 2008 More frequent, intense events - climate change predictions..? Not just cyclones Townsville mini-tornado 2012
  14. 14. Nursery structures particularly susceptible
  15. 15. Designing to resist extreme wind events
  16. 16. AS/NZS1170.2-2011 Wind regions Region C 69 m/sRegion C 69 m/s Region A 45 m/sRegion A 45 m/s Region D 88 m/sRegion D 88 m/s Region B 57 m/sRegion B 57 m/s Regional Wind SpeedsRegional Wind Speeds
  17. 17. Tropical cyclone categories CycloneCyclone CategoryCategory Maximum Gust SpeedMaximum Gust Speed CentralCentral PressurePressure (hPa)(hPa) Damage PotentialDamage Potential (m/s)(m/s) (km/h)(km/h) 1 25 3525 35 90 12590 125 >990>990 Negligible house damageNegligible house damage 22 35 4735 47 125 170125 170 970970 985985 Minor house damageMinor house damage 33 4747 6363 170170 225225 950950 965965 Some roof & structural damageSome roof & structural damage 44 63 7863 78 6969 225 280225 280 250250 930930 945945 Significant roof and structuralSignificant roof and structural damagedamage 5 >78>78 >280>280