عنوان مقاله [English]
In the contemporary decades, Iran’s urban planning system has been evolved. One of the issues that has hardly effected on developing Iranian cities was building density in urban development plans. To this end, the article goal is to address how to determine building density in the approved comprehensive plans of Iran’s provinces centers from first plan to up and to present a typology of it and to explain its traits. Type of research of this article from aspect of method is descriptive- analytical and from aspect of information content is an original article. The required data were gathered by reviewing the formal documents and direct referring to offices to gain them. The gathered data also were analyzed by simply explaining the relationship of between them. The findings have shown that it can be identified four different types of method of determining building density in the comprehensive plans. The first type is traditional that is divided to three sub-types; decreasing, increasing and three-level. The second, third and fourth type are floating, structural-strategic and other methods. The present typology includes three keys points. Frist- the typology follows a unique historical evolution so that each of types and of sub-types have hardly effected on city structure in the time period that in which they had been applied. Second- the regulations of building density-oriented approved, at the noted historical evolution, were the main driver of change in the method of determining building density zoning. Indeed, the milestone of this historical evolution is the laws and regulations set and approved by the High Council of Architecture and Urban Development of Islamic Republic of Iran. According to the figure 3, the main milestone had been the approving of “regulation of increasing density and high rise buildings in the year 1990” that by which, the view and thinking about urban texture development has been basically changed from the inverse relationship between the two variables of the parcel size and the building density to a direct relationship between them. This created a great transformation in the parceling and blocking system, so in the theory and partly in practice the regulations of the cities saw the development of open spaces with the increase of building density. Third- Tehran’s comprehensive plans - approved in years 1969, 1991 and 2007- have had a profound impact on the pattern making of determining density building, so that the beginning of the building density zoning was started by Tehran’s comprehensive plan in 1969, inclusively. Plans 1991 and 2007 were also influenced by the regulations approved by the High Council of Architecture and Urban Development of Islamic Republic of Iran, but later became the pattern for determining the building density for other cities. Totally, it must be noted that impact of each of types and sub-types on the cities -for example Gorgan city- was egregious so that in a section of history increasing of the building density eventuated to minimizing of the parcels size, and in other section of history in the same city increasing of the building density eventuated to maximizing of one. In conclusion, this imbalance in determining of building density has been disharmonized the urban development in I.R.Iran.