ارزیابی میزان تاب آوری کالبدی بافت مرکزی شهرها در برابر سوانح (نمونه موردی: منطقه 8 شهر شیراز) (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
رسالت این نوشتار در پی ارزیابی میزان تاب آوری کالبدی بافت منطقه 8 شهر شیراز است. این منطقه دربرگیرنده هسته اولیه شهر شیراز است و سوای بناهای تاریخی که دارای ارزش میراث فرهنگی هستند. قسمت اعظمی از این منطقه مسکونی است و جمعیتی بالغ بر 35727 نفر را در خود اسکان داده است. روش این پژوهش توصیفی – تحلیلی و مبتنی بر داده های مکانی مربوط به ابنیه موجود در این منطقه است. شاخص های مورداستفاده در این پژوهش عبارت اند از شاخص قدمت بنا، کیفیت بنا، اسکلت بنا، تعداد طبقات بنا، مساحت بنا و مصالح نمای بنا می باشند. مدل های به کار گرفته شده در این پژوهش شامل مدل رگرسیون فضایی برای کشف روند الگو که با استفاده از نرم افزار Geoda انجام شده است؛ و مدل موران جهانی (Moran’s I) برای کشف الگوی فضایی (خوشه ای، تصادفی، پراکنده) تاب آوری کالبدی در منطقه و مدل انسلین محلی موران برای مشاهده خوشه های تشکیل شده در نرم افزار ArcGis به کار گرفته شده است. نتایج پژوهش نشان داد که از مجموع 12717 واحد ابنیه ای که در این منطقه وجود دارد 2371 واحد معادل 6/18 درصد در وضعیت تاب آوری مطلوب هستند؛ و 3587 واحد معادل 20/28 درصد در وضعیت تاب آوری نامطلوب هستند و 6759 واحد معادل 14/53 درصد نیز در وضعیت تاب آوری متوسط هستند. به طورکلی بخش اعظم بافت منطقه 8 شهر شیراز در خوشه های غیرتاب آور و تاب آوری متوسط قرارگرفته است؛ که در صورت بروز سانحه مستعد تلفات جانی و مالی بسیار هستند؛ بنابراین نیازمند اقدام سریع در راستای ایجاد تاب آوری هستند.Evaluating the Physical Resilience of the Central Texture of Cities against Hazards (Case Example: District 8 of Shiraz City)
Extended Abstract
1. Introduction
This study tried to evaluate the resilience of the physical texture in District 8 of Shiraz city. This district embraces the primary core of Shiraz. In addition to the historical buildings that are considered the cultural heritage and identity of the city, a large part of the residential neighborhoods are located in this area. It has a population of 35727 people. The current buildings in this area, like the old and central parts of other old cities of Iran, are in a bad condition because they are so old, as well as due to the type of materials used, the economic and social conditions of its residents, and their resilience against natural disasters. Considering the issues, the main goal of this study was determined to be evaluating the existing buildings in District 8 of Shiraz in terms of resilience indicators and also designing the physical-spatial pattern of resilience in these districts, so that measures can be taken for enhancing their resilience.
2. Method
The descriptive-analytical research used spatial data related to the existing buildings of District 8 of Shiraz. The indicators used in this study are building age, building quality, building skeleton, number of building floors, building area, and building materials. The models that were used are the spatial regression model for discovering the trend of the pattern, which was done using Geoda software, and Moran's global model (Moran's I) for discovering the spatial pattern (cluster, random, scattered) of physical resilience in the district and Moran's local model for identifying the clusters formed in ArcGis software.
3. Results
The findings were evaluated in descriptive and inferential parts. Regarding the descriptive findings, the physical resilience indicators of District 8 of Shiraz were categorized by the ArcGIS software. The results obtained from the maps showed that in terms of the number of floors, a major part of the physical texture of District 8 of Shiraz are in the low resilience and non-resilience category. Regarding the building skeleton, it is worth noting that the data shows that a major part of the texture of District 8 of Shiraz is in low and somewhat medium resilience category. Regarding the building quality indicator, the data showed that most of the texture of District 8 of Shiraz range from low to medium resilience. Regarding grading indicator, the data showed that a high percentage of buildings in District 8 have low to non-resilient resilience. Regarding the age of the buildings the data showed that most of the texture of District 8 are in an unstable condition. In inferential stage of this study, to identify the patterns for the classification of resilience in the texture of District 8 of Shiraz, through the Regression option of Geoda and ArcGis software. The resilience variable was independent variable and dependent variable were decided to be selected indicators. The process of determining patterns for the classification of physical resilience indicators showed that the quality of building indicator coefficient with 0.750 and building skeleton with a value of 0.704 had the highest impact on the resilience of the buildings. Moran's I was used to measure spatial correlation. The value of the statistic was 0.054659, indicating a positive spatial autocorrelation (cluster pattern). The map obtained from the local Moran showed that a major part of the texture of District 8 of Shiraz have medium to very low resilience. According to the map obtained from the GIS environment, of the 12,717 residential buildings located in the District 8 of Shiraz, about 1,076 residential buildings (8.46%) are in a completely resilient state, and 745 (5.85%), have very high resilience, 550 residential buildings (4.32%) have high resilience, 2016 residential buildings (15.85%) are in a completely unsustainable situation, and 994 residential buildings (7.81%) are in a very low resilience status. It is worth noting that most of these residential buildings are considered small and have low durability, which cover most of the southern and southwestern areas of the district. Moreover, 577 residential buildings (4.53%) are in a low resilience state. Therefore, we can say that out of 12,717 residential buildings of District 8 of Shiraz, 3,587 residential buildings (20.28%) are in a poor state regarding resilience against accidents. These are located in Labe Ab, Sardozak, Sang Siah, and Eshagh Beyg neighborhoods, as well as the central parts of Darb Shazdeh and Balakaft neighborhoods. Most of the neighborhoods are residential parts of the district, so the residents of these neighborhoods are in serious danger.
4. Conclusion
The results showed that most of the texture of District 8 of Shiraz is located in non-resilient and medium-resilient clusters. These parts are susceptible to many life and financial losses in case of disasters and need quick initiatives to increase resilience. Considering the results on the shortcomings and obstacles in District 8 of Shiraz, the following measures are suggested for increasing the physical resilience of this district: 1. Improvement, renovation and strengthening the non-resilient and resilient residential buildings based on the requirements in the building code 2800; 2. Examining the vulnerability of the neighborhoods that are in the list of neighborhoods with low resilience (Labe Ab, Sardozak, Sang Siah, and Eshagh Beyg neighborhoods, Darb Shazdeh and Balakaft neighborhoods); 3. Increasing green spaces, re-urbanization, and securing water, electricity, gas facilities and hazards in the central texture, especially the worn-out parts of the district; 4. Implementing restricting policies on construction in the district to prevent consolidation of lands with unsustainable skeletons in the district, especially in Sang Siah, Sardozak, Labe Ab and Darb Shazdeh neighborhoods; 5. Renewing, restoring, and increasing the resistance of the historical textures of the district, especially in Sang Siah neighborhood in which Bazar Bozork is located; 6. Enhancing the flexibility and permeability of facilities of this district, increasing rescue equipment, and paying attention to the physical changes of this district.
تبلیغات
