Vipac Engineers & Scientists Techniques to achieve wind comfort & wind loads on buildings and appurtenances including shades, verandahs, hoardings and walls. Mr Ian Jones, Managing Director Dr Seifu Bekele, Principal Engineer Victorian Technology Centre 14 th May 2013
Overview Introduction Climate Wind Modelling Pedestrian locations Building & Structural appurtenances Wind Tunnel Modelling for Structural Study Comfort & Building Motion Cladding Pressure Porous and attached members Conclusion
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Vipac Engineers & Scientists Techniques to achieve wind comfort Mr Ian Jones Victorian Technology Centre 14 th May 2013
Introduction The history of wind and its effect on mankind is as old as mankind itself Wind as Beneficial Source `` Ventilation Reduce heat accumulation Produce Mechanical Energy Produce Electrical Energy
Introduction Wind source of Damage Hurricane Katrina in US Killed 2,541 people Economic loss 28 billion US Cyclone Sidr in Bangladesh Killed 4,234 people Economic loss 1.7 billion US What do we do we achieve comfort? How do we minimise damage to life and property?
Strong Winds Extra tropical cyclones, Fronts & Depressions 4000 km in diameter Speed of 15 to 25 m/s at 10 m Hurricane, Cyclone, Typhoon 400 to 800 km in diameter Speed 50 m/s to 100 m/s, usually with heavy rainfall Mean wind speed at 10 m > 33 m/s = Hurricane or Typhoon or Cyclone
What is Wind? Meteorological Observation Mean flow Velocity (speed and direction) Velocity Gradient Temporal variation Turbulence Intensity Scale Peak flow Gusts
Earth s wind boundary layer High above the ground the wind is strong and the turbulence low Low down the wind speed is low and the turbulence is high
Wind is lumpy It has frequency Embed 2 movies 33 sec, 15 sec Earth s wind boundary layer
Wind Tunnel Wind Models Boundary Layer Wind Tunnel Roughness Elements Spires, trip Main Characteristics of Wind Mean Velocity Profile Longitudinal Turbulence Intensity Integral Length Scale Australian Wind Engineering Society Recommendation Deaves and Harris (1978) ESDU (1985 and 1986)
Wind Directionality Variations of Wind With Direction (Melbourne)
Wind Tunnel Wind Models Terrain Category 20 times the height of a building
Wind Tunnel Wind Models Power spectrum distribution Velocity correction Impact of Wind Speed on Wind Tunnel Test Pedestrian Test V Cladding Pressure Test V Structural Load Test V 2 2
Wind Tunnel Wind Model Detail Surroundings Model
Pedestrian Level Wind Why do we need it? City Council, Ministry Planning, Development approval (DA) requirement. Ensure pedestrian safety and comfort Ensure suitability of outdoor service locations (Restaurants, swimming pools ) Determine the influence of the new development on existing surroundings
Pedestrian Level Wind Deliverables Visualization of Flow Patterns Information on Safety & Comfort for areas of Interest Safety < 23 m/s Walking < 16 m/s Standing < 13 m/s Sitting < 11 m/s Simple methods Probability methods
Microclimate Study Density of the towers Orientation Spacing between buildings Traffic contribution to thermal built-up and pollutions Anthropogenic (man made) heat
Pedestrian Level Wind
Jenan Gardens, massing study MAKE IT WORK
Jenan Gardens, Façade Noise Map Façade Noise Map Surface Temperature Wind channeling MAKE IT WORK
Pedestrian Level Wind Sand Scour (Area Method) Basic principles Climate and test parameter integrated at testing stage Boundary wind speed calibrated Advantages & disadvantages of this method No need for initial guess Information for wide area Visualizations Effect of modification can be seen on the spot Semi quantitative
Pedestrian Level Wind Irwin sensors (Point Method) Basic principles Dynamic and static pressure measurement Sensor at 1.75 m above surface in full scale Advantage & disadvantage of the method Need initial guess Quantitative measurement Local values Need minimum spacing
Pedestrian Level Wind Irwin sensors (Point Method)
Pedestrian Level Wind Recommendation & Evaluation of Various Mitigation Measures
Pedestrian Level Wind Study Comfort Level Cold Climate Wind speed Temperature Wind chill Hot Climate Wind speed Temperature Humidity Combined comfort criteria Humidex (H = T + h, h = (5/9)(e-10) 20 29 Comfortable 30 39 varying degree of comfort 40 45 uncomfortable 46 and over labor must be restricted
Melbourne Climate March data colored by time of a day December colored by direction CTBUH 2011 World Conference October 10-12, 2011 COEX Seoul Korea
Microclimate Change in natural surface Increase the level of activity (change from low to high rise) Material used for high rise towers Shape of the towers Small Scale to 1km Comfort (adaptive) Radiation/ heat Breezes Temperatures Humidity Pollution Noise
Natural Ventilations Wind Tower Full scale study Wind tunnel study CWE
Natural Ventilation Full Scale Measurement Wind Tunnel Study
Natural Ventilation Wind Tower, Full scale and CFD
Vipac Engineers & Scientists Thank you Victorian Technology Centre 14 th May 2013