Wind Assessments Required For Doncaster Hill High Rise
All developers are required to provide a wind assessment to minimise additional wind flow to ground level.
“Before the development starts,
a Wind Tunnel Assessment that details the extent of wind turbulence at ground level generated by the design of the building must be prepared and submitted to the satisfaction of Manningham Council. Any recommendations to address excessive wind turbulence at ground level must be implemented to the satisfaction of the Responsible Authority”.
However as far as can be ascertained from the planning department records only one high rise apartment proposal has had this permit condition.
Review Article Pinnacle Development Memorandum and Street Profiles
Though it was confirmed a wind assessment had been submitted, strong winds, not present before construction, are now occurring around the Pinnacle apartment building (32 meters) at 632 Doncaster Road, making walking along Frederick Street very difficult and causing some pedestrians to overbalance. The 40 meter high development on the opposite corner at 642 Doncaster Road, which did not have the requirement among its permit conditions, is expected to make the situation worse when constructed since there will be a distance of only 20 meters between the two buildings. This is because maximum wind speed amplification factors increase monotonically with decreasing passage width, contrary to some general building design guidelines proposed in the past for such building configurations. Neither building has incorporated stepped back floor levels, which might have reduced the burden, instead, both have retained a sheer facade into Frederick Street.
Frederick Street Frontages Short Street and Hepburn Road Frontages
Memorandum and Street profiles, from the Manningham Council Planning Department, show a worst case scenario in Frederick Street and a more appropriate configuration in Clay Drive. The Short Street diagram does not indicate what is required at the northern end (40m and 29m heights). Above is a 3D drawing of what has been proposed at the southern end on the corner of Hepburn Road. Apart from a small step back on the fifth floor this development will present a sheer face into Short Street.
3 Comments
Factors of wind turbulence, congestion and light and air, and to a large extent also the architectural effect, vary in nearly a direct ratio as the width of the street upon which the building faces. The actual distance to the building to be built opposite, which in this instance, allowing for front setbacks, will only be approx 20 meters. (part of the Pinnacle building is on the building line) This is not to be confused with the road kerb to kerb measurement which is only 7m. Another reason, though not considered by the authority, for limiting heights (and massiveness) on narrow streets, is the streets inability to handle the number of cars associated with the buildings”.
Amelia T
Proper wind tunnel modelling, especially in the areas depicted, should have been conducted if Manningham council were really serious about resident amenity. For a municipality, already under fire for its dubious claim of ideal conditions for walking and cycling on Doncaster Hill, Manningham council are now ignoring the importance of the outdoor wind climate, when most urban authorities nowadays require studies of the pedestrian wind environment for large high rise construction projects. Construction of tall buildings in a locality of low-rise buildings alters the street level wind environment. The wind which strikes a tall building’s surface gets deflected towards the ground causing high speed winds on the windward side as well as near the corners of the buildings at street level. This leads to discomfort, not only for pedestrian walking but also for cyclists and especially the frail and disabled.
Dean
The stepping back of floor levels (like a stairway) is the usual measure adopted to minimise wind turbulence at ground level where tall buildings are planned on opposite sides of narrow streets, such as in Frederick Street, Short Street, Hepburn Road and Clay Drive.
2C of the Council document, “memorandum and street profiles”, indicates a preferred scenario, however, it appears that council, by approving sheer frontages, have set aside their own advice and have accepted the notion that the loss of apartment yield with floor level setbacks (rear and side), the developments might not be viable and therefore should be given priority over the amenity of pedestrians and cyclists at ground level.
Anonymous