Planning worn-out urban fabric
raza bahador; Zeinab Talebi; shirin toghyani; amirhosein shabani
Abstract
In the sphere of contemporary urban studies, the transition from the traditional paradigm of "vulnerability reduction" to the dynamic approach of "resilience" is recognized as a strategic necessity for managing the complexities and uncertainties of urban hazards. Physical resilience, ...
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In the sphere of contemporary urban studies, the transition from the traditional paradigm of "vulnerability reduction" to the dynamic approach of "resilience" is recognized as a strategic necessity for managing the complexities and uncertainties of urban hazards. Physical resilience, as the tangible fabric of the city, plays a determining role in absorbing shocks, sustaining life, and accelerating recovery following a crisis. District 19 of Tehran, due to its composite and heterogeneous physical nature, the stressful coexistence of dilapidated residential settlements and industrial-workshop land uses, and its location on seismic zones, represents a prominent example of a "high-risk urban ecosystem" that requires a precise investigation of its resilience indicators. The present study was conducted with the aim of modeling and spatially assessing the components and indicators of physical resilience in this district. The research approach is descriptive-analytical and based on spatial analyses within the Geographic Information System (GIS) platform. In order to manage the inherent uncertainties of urban phenomena and avoid binary approaches, fuzzy logic was employed for standardizing and integrating information layers. The conceptual framework of the study was developed across five main dimensions: "structural and population vulnerability," "critical infrastructure and lifelines," "relief spaces and temporary settlement," "hazard intensifying centers," and "socio-economic supporting infrastructure." The analytical findings indicate the existence of profound spatial inequality and structural polarization across the district; such that the northern and central sectors (such as Khanabad Nov and Sharifi) enjoy a relatively favorable status due to resilient structures, optimal access to main arteries, and an appropriate density of vital services. In contrast, the southern and southwestern belt (including Ne’matabad and Ahmad Khomeini Town) are in a critical state and possess high vulnerability due to the synergy of factors such as severe physical deterioration, impermeability of passages, severe poverty in relief and medical infrastructure, and proximity to industrial hazard centers. The results demonstrate that enhancing resilience in District 19 necessitates a transition from general interventions to place-based strategies; such that in the north of the district, the focus is on density management and maintaining infrastructure efficiency, while in the southern half, priority is assigned to physical regeneration, fabric permeability, safety measures for incompatible land uses, and the equitable distribution of relief services.
Planning worn-out urban fabric
Ali Shojaeian; Amer Nikpour; Naser Aligholizadeh Firouz jaei; Mohamad Soleymani
Abstract
Highlights- When infill occurs in a scattered pad area, it can be said that an unused, inefficient space is formed in the city.- Of the 18,650-hectare legal area of the city of Ahvaz, more than 6,726 hectares has the possibility of infill development.- Infill development with a suitable design ...
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Highlights- When infill occurs in a scattered pad area, it can be said that an unused, inefficient space is formed in the city.- Of the 18,650-hectare legal area of the city of Ahvaz, more than 6,726 hectares has the possibility of infill development.- Infill development with a suitable design can be a new type of development with a mixed residential structure and residents with different income levels. IntroductionIn the country of Iran, while the growth and development patterns of towns were determined by local, endogenous parameters, there was some balance between life and the growth of urban economy. As exogenous factors began to play a role, however, some cities grew extremely and irregularly. The city of Ahvaz has undergone extensive physical-spatial changes due to the increase in population, the development of oil industries, the centrality of the province, the establishment of urban services, and the attraction of the residents of the cities and villages of the province in the past decades. This caused the uneven expansion of the city and the emergence of the phenomenon of dispersion therein. The physical parameters that trigger development in Ahvaz include industrial towns, military lands, the airport complex and its facilities, the academic functions of the city, its role as the main communication pathway, the market line to the east of the river, and the integration of suburban areas. These factors have caused many domestic capacities and potentials to remain unused, such as distressed and less developed or undeveloped lands in the city. Therefore, according to the current conditions in Ahvaz, it is a necessity to know about the areas and regions that are prone to infill development, in order to present plans to prevent the phenomenon of dispersion and realization of infill development.Theoretical FrameworkTo describe the notion of infill development, a large number of definitions have been proposed. The most common cause in the world is people’s residence in less wild areas of the city. Given that civilization has often happened in developing countries, and that many of the urban districts in these countries have undergone enormous growth that could be efficient in regard to the key principles of development, a three-dimensional strategy could be adopted for the development of a vast area, involving:1- new construction on a land that has not been developed, or, at least, cultivated, 2- physical rehabilitation of the current unusable buildings, and 3- compatibility with the forms and functions of these buildings.MethodologyThe data used in this research includes Landsat and IRS satellite images, which were processed in the PCI Geomatica environment. The first stage of pre-processing (geometric correction) in this research includes integration of the coordinates of the prepared images. For this purpose, 25 control points were used. In order to better distinguish body spaces from shadows, the histogram equalization operation was also performed on the corresponding images. Then, the distressed fabric map was extracted using the WS model. MLC classification was applied to the images in order to generate and present a map of empty and barren lands in Ahvaz. For this purpose, different bands of two types of data were merged (fused) with image-merging operations to obtain the best combination of bands for classification.Results and DiscussionThe statistical investigations showed that of the total 18,650-hectare area of Ahvaz, 958.2 hectares was identified as distressed fabric, which makes up 5.13% of the city. The identified areas mostly correspond to the central parts of the city (the border between Salman Farsi and Taleghani Streets) and the old fabric around the Ali Mahziar Shrine. Moreover, in almost all the eight districts of the city, more or less scattered parts were identified as distressed fabric.ConclusionThe results of the research showed that of the 18650-hectare legal area of Ahvaz, more than 6726 hectares (including the identified barren areas and distressed fabric) have the potentials for infill development. This value represents 36.2% of the city’s area, which is a relatively large ratio. Furthermore, over the entire area prone to infill development in Ahvaz, including distressed fabric and barren lands, the largest area concerns barren lands, with more than 5768 hectares, and the lowest values pertain to parts of the distressed fabric, with more than 958 hectares, representing 85.7% and 14.3%, respectively, of the entire area studied as prone to infill development. The results concerning the distribution of distressed fabric as identified in this research show that Municipal Districts One and Seven exhibit the largest values, with 3197360 and 3231110 square meters, representing 33.36% and 33.75% of the total distressed fabric of Ahvaz, respectively, and District Five has the smallest values, with 5850 square meters, making up 0.06%. These statistics are highly consistent with the field data, because Districts Seven and One of Ahvaz are considered as the old parts of the city and mainly contain the historic fabric. On the other hand, District Two, with a little more than 1720 hectares, and District One, with about 80 hectares, representing 28.5% and 0.3%, respectively, are known as the most and least severely barren and empty lands. The data in this section seem logical because District One (Old Ahvaz) is considered as part of the historic fabric and the primary, central core of Ahvaz, so the least severely abandoned, barren, and empty land occurs in this area.
