Michelle Maliney Steen

As a large scale site, it is important for the design to reflect and support the future growth of the city. A strong emphasis is placed on the creation of a walkable space where people are the central part of this new architecture. The design will focus on the variety of flows of movement throughout the site, including pedestrian, train and traffic flows. It will embrace the dynamics of the site

The concept of visibility is an important aspect in creating exciting scenes within the space, as well as enhancing circulation routes for a pedestrian focused design.

There is potential to alleviate the congestion of the city and create a space which would act as a major centre of its own, featuring many of the activities that are normally associated with the CBD. These include the 24 hour street life; cafés, bars and restaurants; universities and student culture; a rich selection of shopping; legal, finance, engineering and design firms; and the occasional corporate headquarters. Ordinary people would be able to fulfil more of their recreational, educational, cultural and shopping needs with less travel, encouraging people to travel by foot through and around the site. The scheme will minimize the number of trips needed and allow multi-purpose journeys.

The variable flows of motion throughout the site, including buses, trains and pedestrians are emphasised by site lines and accessibility. The behaviour of the different frequencies of movement throughout the building adds another layer of meaning to it and assists in creating a sense of drama to the space. People don’t only interact with the building, they modify it. There is an added sense of adventure when looking down from a great height and seeing people rushing to work, or looking up and seeing people’s excitement as they watch the trains dart under their feet (See figures 4 & 5).

Figure 4: Void spaces act as viewing platforms.

Figure 5: People interact with and modify the building itself.

The participator will see the experience of space and continuity in terms of a series of movement systems based on different rates of speeds and different modes of movement; each of these interrelated with the others and each contributing its part to the total experience of the site. Movement in and around the site is seen as the vehicle of experiencing the varying modes of movement already existing in the site.

The emphasis on site lines and accessibility not only enhances the visual experience, it allows for improved circulation and navigation of the space. The spatial flow meets the functional needs of the building which is to welcome a large public comfortably and at different times of the day.

It is apparent that pedestrians are highly sensitive to the complexity of routes and they tend to choose the simplest path. This means that overall, movement flows tend to become concentrated on the paths that offer the simplest links. The design of an area can have an important effect on supporting or hindering pedestrian movement. The layout can either provide clear, simple routes that are easy to use, or it can provide more labyrinthine, confusing routes which tend to discourage walking.

It is important to maximise visibility throughout the design. Visibility is measured as the area of useable space visible to a pedestrian at any point in the grid. This is one of the most important factors determining the pattern of pedestrian flows in models of movement. Research in many different cities over the last 20 years has shown that pedestrian movement flows tend to be greater on routes that provide clear and direct visual links through the built environment (so-called 'desire lines') than on complex routes where people cannot see directly where they want to go (Desyllas et al 2003: “Pedestrian Demand Modelling of Large Cities” http://www.intelligentspace.com/download/Pedestrian%20Demand%20Modelling%20of%20Large%20Cities.pdf).

Pedestrians rely heavily on visual information to orient themselves and move about, so their movement is highly influenced by this. In an urban configuration, spaces with high levels of visibility are likely to support natural navigation for people moving around the area. These spaces will also see higher levels of movement, as they are direct and extensive routes (see figure 6). Where visibility is low, people are less likely to find their way around easily. Low visibility indicates routes that are less direct and are generally shorter.

 Figure 6: Exposed to the sky, the train platforms act as a viewing platform to the spaces above.

The trajectory of the travellers most direct routes through the site were studied using snapshot animation (See figure 7). This mapping of pedestrian movement through and around the site is utilised and manipulated to create a dialog between the design and its context. The process generated logical connections which flow into each other, creating a sense of path and direction. It also aided in defining the positive and negative spaces in the building. The positive spaces form the areas which held direct links through the site; whilst the negative, less travelled spaces form the various voids within the building.

The walls and voids which emerged facilitate in directing the movement of people through the building. They act as channelling mechanisms. They follow the length of the building, north and south, to allow for infinite site lines through the space (See figure 8). The walls are treated as edges, defining the paths of movement and guiding the flow of spaces. These help to create a continuity of circulation. The experience evoked is navigating the area, and seeing visible all the aspects of the activity in the site, such as the arrival of trains, bus stops and waiting areas.

Figure 7: Movement study (snapshot animation)

                                  Figure 8: Wall and Void results

The movement study considered not only lateral movement through the site; it also mapped the vertical movement (See figure 9).

Figure 9: Vertical movement study

It became apparent through observations of the movement study that the main concentration of users will frequent the lower levels of the building. The lower level contains the train station, which is a major transit hub that disperses people into the city. It is an area where vast numbers of people pass through on a daily basis on their way to their next destination. The upper levels are less frequented, thus, embrace a more relaxed atmosphere. This vertical study was a major decisive factor in the allocation of programmatic spaces;

• The ground level, being the fast paced area has been allocated space for access, interchange, open flow of traffic, daily essential stores & take away shops for those quickly passing through. The train platforms at Central Station connect spatially with the main entrance to the station, integrating them into the main distribution zone.
• The mid-level best accommodates a more relaxed programme, including café’s, retail stores and offices.
• The upper level, being a much slower space is ideal for restaurants, clubs, accommodation and viewing platforms for those planning to stay a while.
• Finally, the roof becomes inhabitable and serves as a garden space as well as a viewing platform, beyond its functional demands. As a viewing platform, it allows the visitor to engage with the city as a whole. Viewing a city from a great height is a way of taming it. However, the observer is also rendered vulnerable by this experience (See figure 10).                                                                                                                                                                       “The exhilaration we feel when we view a great city from one of those rare vantage points where one can ‘take it all in’ is the thrill of seeing in one moment the enormity of human work” (Kasinitz 1995:3).

Figure 10: Sky Garden