I’ve been playing with something new to me. Well, database programming isn’t new, and urban design isn’t either. But on this project I’m bringing the two together. It’s mostly investigative, experimenting with relatively new parametric software, trying out new methods. It’s been consuming all my non-work time lately. This is the next step I’ve been looking for – bringing art and science together – althought the science part has taken the lead and art will probably have to follow after, once I’ve got my head around it all a bit better.
The software I’m using for BIM and 4D sequences is Gehry Technologies Digital Project, and Ms Excel data spreadsheets to hold parameters.
I’m looking at design of urban form through parametric modelling, focusing on pedestrian comfort with regard to wind, sun and rain. Further study would look at pedestrian safety, and at faster pedestrian commuter links. The forms I’ve used are very basic – rectangles and grids, however this software is very powerful – making minor changes to a few parameters can result in the whole city form changing dramatically.
The site is located over the railway lines north of Spencer Street train station, recently redeveloped into Southern Cross Station. The site is between Bourke Street pedestrian bridge, La Trobe Street bridge, DFO shopping area, and Telstra Dome.
The project site is in an optimal location to act as a crossroads between many different surrounding uses. Vehicular, tram and train networks are well developed, however pedestrians, especially in terms of their comfort, are poorly catered for.
Pedestrian comfort levels
Pedestrian comfort levels were used to establish goals for the range of acceptable wind speeds at various points across the site. These levels were broken down by the type of usage, and into three categories: pleasant, usable, difficult. The numbers were based on several different studies, however due to large variation between studies, the selected figures can only be taken as an estimate of desirable local wind speeds.
Regional wind speeds: Because the strongest winds affecting the area are from the north throughout the year, alleviating them was the primary wind related objective. Although there are notable south and south-westerly winds during summer, these tend to be cool breezes and are generally desirable. Opportunities exist for shielding. North shield could extend beyond La Trobe street bridge to shield the site from the strong northerly winds in winter and summer, and would be predominantly functional with energy harvesting structures. South shield could be located above the Bourke Street pedestrian bridge and be predominantly sculptural. West shield could be located between Telstra Dome and La Trobe St bridge.
Wind: local wind speed, regional wind speed, terrain/height multiplier, shielding multiplier
Surrounding structures: average height, number of, average breadth, average spacing, height of structure at point, breadth of structure at point
Building heights are randomly generated from the height range resulting from wind based data, and are dynamically linked to existing surrounding structures. If one building changes, resulting design form parameters of other buildings change, too.
Stereographic Sunpath Diagram – azimuth and elevation at 9am and at 3pm
Street orientation – layout of streets and lanes based on the existing Melbourne CBD layout
Building facade at intersections with main streets
Locations of sun shafts can be generated based on assigned percentages of desired sun and shade at certain times of the year, in particular locations or street orientations. Further study could look at placing the sun shafts at heights above ground level, and assigning them additional parameters.
The intersections of building volumes and sun shafts can be defined as limited build zones. For example, a stipulated proportion of the intersection volume must allow wind and light to pass through; the remainder of the intersection volume is permitted to block wind and light.
It’s all highly exploratory, but I believe as software becomes more advanced, we will be able to use data to help us define form in a way that serves not only the aesthetic, but also helps us create healthier urban environments.