competition "Kriehubergasse", 1st prize for ARTEC Architekten
The potential of the “street” as a structural element in urban design
Richard Manahl, ARTEC Architekten.
Talk given at the conference Abstract City: Streets, Universität der Künste Berlin, 2008
An attempt at a system to clarify terms as limit value consideration
The horizontal plane is the basis on which human beings move and stand, the vertical is the special case for changing planes. A standard classification of urban design structural elements according to their usability in space remains both banal and valid: in one dimension: as “street”, in two dimensions: as “square”, in three dimensions: as “building” –. Through connecting these structural elements “city” is created.
The street is a linear, mono-dimensional element that connects here and there – with the exception of the bridge, where the specific nature of the linear course becomes evident.
The street is a traffic route and infrastructure medium: it creates connections not only in the form of transportation – media such as water, gas, electricity or telephone also form part of the cross-section.
As long as no further element is added, the information content, i.e. the change of possibilities, remains zero along the line of the street, apart from encounters and views.
One form of “informedness” of the linear strand is made possible by adding individual events (buildings or squares). Above and beyond the function of connecting places, here a medium of information is created: this informed equipping generates “possibilities” for those who can “read” (i.e. use) them, that is a form of “behaviour”.
The degree of “informedness” is increased through the proportion of individual events in the overall accumulation that are publicly usable and devoted to freely accessible exchange.
In the cross section the transition from street space to the closed mass of the buildings becomes the main criterion for usability. A direct collision between open and closed space brings with it the greatest difficulties as regards appropriating public space positively rather than hastily making one’s way through it
Alongside those buildings that are, from the start, dedicated to the public realm, the structural shaping of the buildings and their possibilities in terms of adaptation and change are decisive for the potential of a street.
In addition to the publicly accessible content of buildings the announcement of this content becomes an additional factor as regards differentiating surfaces and legibility. A further factor in the accumulation arises on the street itself in the form of the supply of seating, shade and casual shopping facilities.
A further form of “informedness” develops where two streets intersect: the second dimension emerges, there is a choice of goals. It is in the addition of this two dimensionality that the “grid” develops: a form of dividing up space as a meaningful approach to providing similar conditions for similar needs such as route connections or plot sizes.
In the “grid” or mesh the border value of the orthogonality of the threads is the rule rather than the special case. Other possibilities represent special cases that arise through the presence of existing buildings or through the topography. Although the fields are identical the grid allows them to be filled in different ways.
The newly emergent differentiation of traffic becomes relevant for the mesh of streets in the modern city as far as the quality and dimension of the streets is concerned. The different speeds and requirements of pedestrians, cyclists, public transportation and motorised private traffic lead to segmentation of the traffic strands.
With the advent of the car and, with it, mobility of a previously unknown kind for (almost) all , modernism in its approach to urban planning abandoned a consensus for laying out new towns or parts of towns that had been valid until then.
Suddenly the structural elements could be cleanly separated, kept at a distance, clean in the sense of hygiene and health, tidiness also as a world view.
In the course of this the grid as a basic principle was not abandoned, but suddenly a weakly defined intermediate space of considerable size from a pedestrian’s perspective was placed between the street and the building. The context and the interaction were lost, the intermediate space prevents the two structural elements from communicating with each other.
However, in abandoning the principles of pure functionalism the principle that “the art of architecture” and “urban planning” provide context and interplay is also abandoned.
But even if today there is apparently no idea about how architecture and urban planning could be brought back together into a context, the “inhospitable nature of our cities” is nevertheless not the same as when Alexander Mitscherlich’s book appeared because once again interest is again being focussed on the centres of cities and on the periphery.
A third dimension of use becomes possible by overlaying grid structures on several planes, and their vertical connection. The advantages of short route connections of surfaces as found in buildings can be adopted in the one- and two-dimensional structural elements: “increase of density”, multiplication of the existing building ground as usually found in buildings, can be employed for the city as a whole.
This three-dimensional overlay can emancipate itself (as a consistent utopia) and can lead to the dissolution of the existing structure, the constraints of the building site and the restrictions of the topography.
Complexity instead of banality and therefore street space of real quality can develop through the openness of use and openness of the structure of the buildings erected in a direct relation to the street.
The street is the “spatial body in the building mass” (Rowe and Koetter, Collage City), the extent of the spatial body is the important definition .
The frequency of a street is dependent on the quality of the surface, i.e. the degree of informedness, along its length.