Cohering Shiraz Central Area: Urban Design Guidelines toward a more Coherent Urban form Based on Complexity Theory

The old cities of Iran have different qualities that some of them cannot be seen in contemporary cities. Experiencing the invasion of cars and people’s new life style during the last century, old city gradually lost their forms and function. Such changes caused new challenges and demands by which various qualities of old cities have been altered or vanished forever, as urban cohesion and wholeness. Cohesion and wholeness are two related concepts where the former one is a fundamental condition to reach the later one. In this paper, wholeness is defined as an integrated system, consisted of different elements and their relations which can tolerate no changes, since a trivial one may change it into another system. Moreover, cohesion is considered as an important quality of relations between different elements of the whole. Although cohesion can be seen with various scales in different layers of cities, the layer that is emphasized in this paper is the built environment.For the theoretical framework of this paper, we used complexity theory with emphasis on Christopher Alexander and Nikos Salingaros theories about wholeness and coherent urban form. We extracted principals of urban coherence to evaluate the cohesion of central part of Shiraz and to make design guidelines to achieve cohesion. These principles are: coupling, diversity, boundary, forces, organization, hierarchy, interdependence, and decomposition. And also a wide range of valid records, documents, and maps are used which enabled us to illustrate the main structure of this old city, before its destruction in Pahlavi era. Taking into account all of these principles, we focused on these questions: does cohesion exist in the ancient area of this city? Can we find some application of these principals in the old city that could be as a foundation for design guidelines?As our first contribution, we used the principles and evaluated their existence by applying them to an old area of Shiraz city which dates back to the Zand dynasty. Due to our promising results, mentioned principles can be seen in old city. On one hand, the existence of these principles in the old city means that the old area follows the rules of complex system theory so it emphasizes that the old area is a coherent area. On the other hand, it suggests some design principals and patterns that can be considered as a foundation for design guidelines towards coherence and coupling contemporary city. Our second contribution is a design guideline for cohering contemporary cities by connecting two adjacent areas. These guidelines are: complementarity of adjacent areas, increasing the permeability of area in its edges, reducing unlimited views, reducing parcel size of edges, reducing the distance between adjacent areas, increasing the permeability of edge parcels, priority of pedestrian movements, increasing the diversity of functions, increasing the diversity of forms, and increase the homogeneity of parcels in a street. By using these guidelines we can increase the connectivity of two adjacent areas in the first step and increase the cohesion of the whole city in the last step.... Key words: Wholeness, Form Cohesion, Complexity System Theory, Urban Form Principles.