تحلیل ناپایداری بافت های شهری و پهنه بندی میزان آسیب پذیری در برابر زلزله با استفاده از GIS&AHP ، نمونه موردی: بخشی از هسته مرکزی شهر سنندج

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استادیار شهرسازی، دانشکده هنر و معماری، دانشگاه کردستان، سنندج، ایران.

2 دانشجوی کارشناسی ارشد برنامه ریزی شهری، پردیس هنر های زیبا، دانشگاه تهران، تهران، ایران.

چکیده

شهر سنندج در گذشته دور براساس مقتضیات معماری و اقلیم و تا اندازه ای ضروریات اقتصادی- اجتماعی تکوین یافته و به مقاوم سازی آن توجه نشده است. ریزدانگی قطعات، استفاده از مصالح نامرغوب در ساخت ابنیه، فرسوده بودن اغلب ساختمان ها و کمبود فضاهای عمومی و کمبود سرانه فضای سبز، عرض کم معابر و پیچ د رپیچ بودن آن ها و عدم رعایت اصول فنی و شهرسازی و آیین نامه 2800 در خصوص این بافت، سبب آسیب پذیری بالای این بافت شده و این امر طبیعی است که آنچه در رودبار و منجیل و بم اتفاق افتاده به شکل مشابه می تواند برای سنندج نیز اتفاق افتد. هدف اصلی از این پژوهش، ارائه روشی برای تحلیل آسیب پذیری لرزه ای بافت های قدیمی با استفاده از شاخص های آسیب پذیری لرزه ای به منظور کارآمد نمودن فرآیند مدیریت بحران زلزله در بخشی از هسته مرکزی و قدیمی شهر سنندج است. در این مقاله تلاش شده که مدلی براساس تحلیل فضایی برای بررسی میزان آسیب پذیری در اثر زلزله با استفاده از توابع تحلیل فضایی GIS ارائه شود که بتواند معیاری برای میزان خطرپذیری ناشی از زلزله در هسته مرکزی شهر سنندج باشد. بدین منظور با ترکیب فرآیند تحلیل سلسله مراتبی ( AHP ) و روش فازی به سنجش میزان آسیب پذیری محدوده مورد مطالعه پرداخته شده است. سپس به تحلیل آماری نقشه های آسیب پذیری و متغیرهای تحقیق به کمک نرم افزار SPSS پرداخته شده است. نتایج تحقیق نشان می دهد که درصد بالایی از قطعات موجود در محدوده مورد مطالعه با آسیب پذیری بالایی در برابر زلزله روبرو هستند و این امر لزوم برنامه ریزی صحیح جهت ساماندهی بافت مذکور را نمایان می سازد.

کلیدواژه‌ها


عنوان مقاله [English]

Analysis of Urban Instability and Vulnerability in Old Texture by Using GIS & AHP, Case Study: Sanandaj City

نویسندگان [English]

  • Kyoumars Habibi 1
  • Komar Javanmardi 2
1 Assistant Professor, Department of Urban Planning, University of Kurdistan, Sanandaj, Kurdistan, Iran.
2 M.A. Student in Urban Planning, University of Tehran, College of Fine Arts, Tehran, Iran.
چکیده [English]

Urban vulnerability is a widespread and multidimensional phenomenon that covers all the factors of the city which is rapidly increasing due to the factors’ interdependencies. Therefore, urban earthquake vulnerability has been studied from different perspectives and this research has tried to examine all the factors affecting vulnerability. It also has been tried to provide a model based on spatial analysis to investigate the earthquake vulnerability level, using GIS spatial analysis functions that can be considered as a criterion to determine the earthquake vulnerability level in Sanandaj downtown. Earthquake danger width map is made in three steps. The main maps that are effective in the destruction resulting from earthquakes, are ranked and rated based on their importance in the first step. These maps, in the second step, are turned into Fuzzy ones using Fuzzy functions. In the third step, these Fuzzy maps are merged according to each map’s score based on hierarchy analysis method. It should be mentioned that maps related to the distance between users, open spaces and clinics are made using pathway axes and network analysis extensions. In this way, the real distance between any given places and neighboring usages can be calculated. Finally, main vulnerability factors and variables are analyzed statistically. According to the statistical analysis using SPSS software, it becomes evident that there is a meaningful correlation (R= 0.926, n= 1711) between the overall vulnerability of the being studied contexture and its physical vulnerability and also there is a direct and average relationship between overall vulnerability and access vulnerability. The relation between overall vulnerability and socio-economical vulnerability and the relation between physical vulnerability and access are direct and weak. The next table contains plural R values that measure the variability ratio of the dependent variable and also R square (determining coefficient) which is the value of dependent variable that is determined by the independent variables. For instance, according to the value of  0.861 for the determining coefficient physical vulnerability, this variable determines 86.1 percent of the changes of dependent variable (overall vulnerability). The results show that 90 percent of the contexture has average or over-average earthquake vulnerability, 42 percent of the pieces in the being studied district are high earthquake vulnerable and only 10 percent of the contexture of the being studied district are low earthquake vulnerable to. Parts with high earthquake vulnerable are not, generally, in a good condition from the viewpoint of all factors. In fact, high population density, high structure density, the pieced small narrow pathways and blind alleys, lack of access to open spaces and clinics, old buildings, low earthquake resistance structures, and high level of earthquake vulnerable for people are among some characteristics of these areas. Statistical analysis of the vulnerability maps and variables shows that the main factor of earthquake vulnerability of Sanandaj downtown is a physical factor. The main vulnerability factors including structures’ quality and skeleton, show the necessity of the paying more attention to the reforming of physical indexes of the Sanandaj contexture.

کلیدواژه‌ها [English]

  • vulnerability
  • Earthquake
  • Sanandaj Central Core
  • Fuzzy logic
  • AHP
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