تبیین ارتباط فرم‌‌شهری با تاب‌آوری در برابر سوانح در سطح محلات کلان‌شهر تهران

درک فرم‌شهری تاب‌آور بسیار مهم و ضروری است زیرا در فرایند برنامه‌ریزی شهری، مصرف منابع، پویایی و حتی حیات شهر پس از مواجهه با سانحه تحت تاثیر تصمیمات پیشین در زمینه ساختار کالبدی شهرها است. فرم‌شهری به‌عنوان ساختار شهر بر فروپاشی و یا پایایی سیستم شهری در برابر سوانح می‌تواند تاثیر بگذارد. ازسوی‌دیگر، فرم‌شهری به‌مثابه نمود فضایی و کالبدی فعالیت‌های انسانی، بستر و زمینه‌ای برای ابعاد مختلف اجتماعی، اقتصادی، زیست‌محیطی تاب‌آوری است. با وجود تاثیر فرم‌شهری بر تاب آوری، فرم‌شهری تاب‌آور همچنان به‌عنوان یک موضوع اکتشاف‌نشده تاب‌آوری شهری است. در این پژوهش با تکیه بر ویژگی‌های شهر تاب‌آور، ویژگی‌های فرم تاب‌آور همچون استحکام، تنوع، ارتباطی، کارآمدی، افزونگی و مدولاریتی معرفی‌ شده‌‌است. سپس با هدف شناسایی مولفه‌های فرم‌شهری که ویژگی تاب‌آوری را دارند، ارتباط معنی‌دار شاخص‌ها و مولفه‌های فرم‌شهری با تاب‌آوری و ابعاد آن تبیین شده‌است. برای این کار، در این پژوهش با انتخاب محلات کلان‌شهر تهران به‌عنوان محدوده موردمطالعه (368 محله)، پس از تعیین و سنجش ابعاد تاب‌آوری و مولفه‌های فرم‌شهری با استفاده از تحلیل عاملی، از تحلیل رگراسیونی جهت تبیین ارتباط میان مولفه‌های فرم‌شهری و تاب‌آوری و ابعاد آن استفاده شده‌است. نتایج حاکی از آن است که مولفه‌های مختلف فرم‌شهری بر عوامل مختلف تاب‌آوری تاثیر متفاوت گذاشته و در برخی موارد، رفتار متضادی بر مولفه‌های تاب‌آوری داشته‌اند. در میان ابعاد تاب‌آوری، تاب‌آوری جامعه‌ای هیچ تاثیری از مولفه‌های فرم‌شهری نمی‌گیرد. بیشترین ارتباط میان مولفه متراکم بودن با تاب‌آوری زیرساختی مشاهده شده‌است. بعد اجتماعی و تاب‌آوری کل بیشترین ارتباط را با مولفه دسترسی به قطعات داشته‌اند. درمجموع ارتباط مستقیم مولفه‌های دسترسی به حمل‌ونقل عمومی و دسترسی به قطعات و ارتباط معکوس مولفه‌های دسترسی به مراکز تجاری و میزان فضای باز و سبز با تاب‌آوری و ابعاد آن، نشان از تاثیر مولفه‌های فرم‌شهری بر افزایش یا کاهش تاب‌آوری در برابر سوانح دارد.

Analyzing Relationship between Urban Form and Disaster Resilience at Tehran Metropolis Neighborhoods

While it has been only two decades since resilience as a concept entered the field of urban planning, there has been an increasing interests and a wide range of studies surrounding the issue in this short span of time. Considering this fact, surprisingly a few passionate endeavors have attempted to assess urban resilient form as the subject, while urban form as the structure of the city can directly influence its collapse or resistance in facing the disasters. In fact, variation in the form of a city can have a negative or positive influence on its resilience. Moreover, urban form as the spatial and physical embodiment of social and economic interactions of cities is the context of various social, economic, and environmental aspects of resilience. So it is a bit of a surprise that despite this undeniable influence of urban form on resilience, their relationship has not been thoroughly explored. Thus, by considering the features of resilient city this research has attempted to embark on redefining the urban structure from the resilient point of view and determined certain characteristics of #39;urban resilient form #39; such as robustness, connectivity, redundancy, modularity, diversity and efficiency. Then, for obtaining the qualities of resilient urban form, it is tried to analyze a meaningful relationship between the indicators and factors of urban form and the extent of resilience, in order to specify urban resilient form together with the contributing factors affecting its resilience. Multidimensional urban form and resilience together with the impact of the scale on the components and parameters make it necessary to investigate the phenomenon and their relationship in a specific scale.This research takes neighborhoods rsquo; scale to look at its case study, Tehran metropolitan area, in order to assess its resilience in the face of disasters, in addition to specify the modifier indicators of urban form in the neighborhoods of Tehran metropolitan city and examine the relationship between the components of the urban form and resilience. For achieving the aim of the study, initially the indicators and the scale of resilience in 368 neighborhoods have been evaluated to access the relation between the urban form and resilience scale. It benefits assessable indicators suggested by three resilience assessment approaches; CDRI, CRI, and BRIC, in the scale of neighborhood units. By taking the advantage of exploratory factors analysis, four domains of infrastructure, economic performance and community have been specified and then according the points which the factors obtained, the resilient degree of the neighborhoods were specified. Furthermore, the collection of six factors including denseness, green and vacant area accessibility, nonpermeability, retail accessibility, components and transit accessibility along with 22 indicators are introduced as factors and indicators for urban form in the neighborhoods of Tehran metropolitan city.Finally, for obtaining the main goal of study which is illuminating the relation between urban form and resilience indicators in the neighborhoods of Tehran metropolitan city, linear regression analysis has been applied. The results of this analysis show that different urban form components have various and even contrasting influences on resilience. The strongest relationship can be found between infrastructure resilience and density, as the main component of urban form. The economic performance aspect is also, like infrastructure resilience feature, has been most positively influenced by density factor. Among all of urban form factors, accessibility to components has the most powerful bond with social aspect and the whole resilient composite index. Community resilience is not influenced by urban form components at all and there is no relationship between them whatsoever. There is a direct relationship between accessibility to public transportation and components availability with resilience. On the other hand, factors such as accessibility to business centers and the amount of open and green spaces have a reverse relationship with it. Overall, the influence of urban form components on increasing and decreasing the degree of resilience can clearly be demonstrated. However, the results of the effects of urban form components on resilience pose challenges for future studies. Economic performance dimension aside, these challenges include the negative impact of the density component on social resilience, the negative impact of the permeability component on infrastructure resilience and the negative impact of access to business centers on the dimensions of resilience.