Dense urbanism at the old edge: conflict and reconciliation of streets and buildings

Abstract

In the last few decades, new centers have emerged at the edges of traditional cities and pre-World War II suburbs. As these evolve, do they converge towards the urban forms of traditional cities? This question is explored based on a study of urban areas in the Atlanta Metropolitan Region. Atlanta Downtown, Decatur and Marietta, are compared to the new centers in Buckhead, Cumberland and Perimeter. The evolution of the street network of Buckhead is examined in detail. The morphological history of a particular urban block in Buckheadâ "the Tower Place blockâ "is documented. Morphological analysis, focusing on street patterns, block shapes and sizes, property boundaries and building footprints, is complemented by Space Syntax, focusing on the structure of street networks and connectivity. It is shown that new urban centers tend to grow on very large blocks accessed through major transportation infrastructure, but situated in otherwise sparse and fragmentary street environments. As these centers grow and as the density of land use increases, a secondary private road system is created, to take advantage of development potential and provide access to major building investments. The effective fragmentation of the large blocks suggests a pattern of metric convergence towards an optimum block size. In traditional cities, however, the street network is stable over time and acts as the framework for changes in architecture and land use. In the new centers, the secondary road system serves to access particular private investments without regard to the creation of a public framework of connections. From a syntactic point of view, the new centers are spatially unintelligible, thus substantially diverging from traditional cities, even as they accommodate dense mixed use developments. The thesis points to the need of developing and using subdivision regulations and zoning classifications in order to better regulate the spatial structure of new urban centers in the future.