Passive Defense
Hossein Mahdizadeh; Ghader Ahmadi; Mohammadreza Pakdelfard; Mahsa Framarzi
Abstract
Highlights
- The vulnerability of the semi-grid urban form is greater than that of the grid urban form with respect to the indicators of plot area, fabric pattern, building density, building age, building quality, distance from rescue centers, distance from hazardous centers, building facade, ...
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Highlights
- The vulnerability of the semi-grid urban form is greater than that of the grid urban form with respect to the indicators of plot area, fabric pattern, building density, building age, building quality, distance from rescue centers, distance from hazardous centers, building facade, population density, and building structure.
- The vulnerability of the grid urban form is greater than that of the semi-grid urban form with respect to the indicators of distance from open spaces, area of worn fabric, distance from faults, and distance from the main thoroughfares of the city.
- The grid urban form exhibits better performance than the semi-grid urban form in terms of vulnerability from the perspective of passive defense against earthquake.
Introduction
The present age is referred to as the age of urban vulnerability, because cities face natural hazards and technological crises from various aspects on the one hand and socio-security crises on the other as urban life becomes more complex. The issue of passive defense is no longer defined as a mere research topic but as a vital requirement for governing any country, both upon crisis and at other times, for maintenance of its material and spiritual values. Therefore, the theoretical and practical position of defense and defense against the crisis is very important in this area. On that basis, the application of passive defense and consideration of its principles in urban planning can greatly reduce the destructive effects of such crises. The checkered city of Salmas, Iran, a mid-sized city, according to Iranian Space Agency, with a population of 91239 people, is located in a region with high relative risk based on the relative earthquake risk zoning of Iran, from the study of the National Physical Plan of Iran. Due to its location on a fault, evidenced by the devastating 7.2-magnitude earthquake in 1930, it is very important in this city to observe the principles of passive defense in urban planning. Accordingly, this study was conducted with the aim of measuring and modeling the vulnerability of grid and semi-grid urban forms in Salmas against earthquakes from the perspective of passive defense.
Theoretical Framework
With respect to the type of fabric, there is less vulnerability and greater relief in case of earthquake in regular continuous fabrics over flat lands featuring roads with low or medium confinement and blocks with one or two regular rows of construction. The grid urban form of the roads is also effective in the provision of relief due to easy access. Regular and stepped discontinuous fabrics over foothill lands are moderate in terms of efficiency and vulnerability, and irregular continuous fabrics over flat areas are less effective against earthquakes. The indicators of urban fabric in the assessment of vulnerability against earthquake include the method of attachment of adjacent segments to the passage, adjacency of the open and constructed spaces of each section to the passage, extent of confinement of the fabric, pattern and size of the urban blocks, and pattern of combination of the roads and urban blocks.
Methodology
In this applied analytical research, data collection was carried out through library studies, existing articles, field studies, and 2016 census information from the Statistical Center of Iran. Thus, the effective indicators of vulnerability were extracted from the perspective of passive defense after the relevant documents and resources were studied, and fourteen indicators were then selected from among various influential factors according to their availability for specification of vulnerability in Salmas to obtain the research output. Given that each of the indicators effective in the specification of the vulnerability of the coefficient has a different importance, the opinions of the elite were used in this research to determine the weight (coefficient of importance) of each indicator. To weigh the indicators according to the BWM method, ten questionnaires with contents based on a pairwise comparison of the indicators were formulated given the preference of the best indicator over the others and the preference of the other indicators over the worst. In the next step, the data from the questionnaires were entered into the GAMS software and calculated and analyzed. The weight calculated with the value of λε obtained for the ten questionnaires was 0.097, which indicates the stability and consistency of the calculated weights due to its proximity to zero. For spatial analysis, the information layers of the indicators were first digitized and edited in the GIS software, and each of the indicators was multiplied by the significance coefficient calculated by the BWM method through conversion of the information layers into rasters and their standardization with large and small fuzzy functions and Boolean logic. Using the weighted sum of the indicators to measure vulnerability, the grid and semi-grid urban forms in Salmas were addressed separately.
Results and Discussion
Among the calculated weights of the indicators in GAMS, the highest concerned urban from pattern, with 0.164, and the lowest pertained to building façade, with a significance coefficient of 0.030. The average value of λε obtained for the ten questionnaires was 0.097, which indicates the stability and consistency of the calculated weights due to its proximity to zero. The results of combining the indicators in the grid urban form in Salmas demonstrated that there were 4866 parcels in the very low vulnerability zone in the grid urban form, 2719 parcels in low vulnerability, 2862 in medium vulnerability, 3435 in high vulnerability, and 430 parcels in the very high vulnerability zone. In the semi-grid urban form, there were 611 parcels in the very low vulnerability zone, 2598 in low vulnerability, 3669 in medium vulnerability, 5350 in high vulnerability, and 3057 parcels in the very high vulnerability zone.
Conclusion
In general, it can be stated that the level of vulnerability in the grid urban form is less than that in the semi-grid urban form. The semi-grid urban form was found to be more vulnerable than the grid urban form based on the indicators of area, parts pattern, building density, building age, building quality, distance from rescue centers, distance from hazardous centers, building facade, population density, and building structure. Moreover, the grid urban form was found more vulnerable than the semi-grid urban form based on the indicators of distance from open spaces, range of worn fabric, distance from faults, and distance from the main thoroughfares of the city.
Urban livability
Aram Khezerlou; Asghar Abedini
Abstract
Highlights
- The highest weight concerned the indicator of building quality, and the lowest pertained to the area covered by sewage.
- The rate of livability is higher in the old part of the city of Urmia, Iran than in the new part.
- The rate of livability is in better conditions in the old part ...
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Highlights
- The highest weight concerned the indicator of building quality, and the lowest pertained to the area covered by sewage.
- The rate of livability is higher in the old part of the city of Urmia, Iran than in the new part.
- The rate of livability is in better conditions in the old part than in the new part based on the indicators of access to the main thoroughfares, average land price, population density, access to sports and recreational use, access to medical use, access to academic and cultural use, access to commercial use, number of literate people, and number of employees.
- The rate of livability in the new part is in good conditions compared to that in the old part based on the indicators of building quality, area covered by sewage, and access to green spaces.
Introduction
The increase in the development of urban population and replacement of concern for quantitative standards by consideration of qualitative approaches has led to a rise in the quality of urban life and urban livability, where the role of officials and urban management is important, along with the need for a comprehensive study of various dimensions in the city. Following the rapid population growth as a result of migration and the unplanned expansion of the city of Urmia, Iran, the capital of West Azerbaijan Province, and the consequent problems, the need for a comprehensive effort to save the city and improve the quality of life therein has been highlighted more than ever. In response to these problems, various theories and approaches have been proposed, one of which is the livable city approach. Given that livability is a complex, multidimensional concept, and its patterns are completely different from one region to another, no comprehensive model has been presented so far of the effects of livability indicators in the old and new parts of cities in the current conditions and the relationships between them. Therefore, this comparative study was intended to investigate the extent of livability in the old and new parts of Urmia based on the relevant indicators.
Theoretical Framework
Livability is defined as the quality of life experienced by the inhabitants of a city or region. Kennedy and Bai believe that the concept of livability is defined by terms such as the well-being of the society, and represents the characteristics that turn a place into one where people always want to live.
Methodology
In this descriptive-analytical applied research, data collection was conducted through library studies, available articles, field studies, and census information released in 2016 by the Statistical Center of Iran. Thus, after the resources relevant to livability were studied, twelve indicators were selected from among various effective factors to obtain the research output, given the availability of data on Urmia. These indicators include access to medical use, access to commercial use, access to sports and recreational use, access to green space use, quality of buildings, area covered by sewage, access to academic and cultural use, number of literate people, population density, average land price, number of employees, and access to the main thoroughfares. Given that each of the indicators effective in specification of livability has a different coefficient of importance (weight), the opinions of the elite were used in this article to determine the weights of the indicators. To weigh the indicators according to the BWM method, thirty questionnaires were developed with contents based on their pairwise comparison in terms of the preference of the best indicator over the others and the preference of the other indicators over the worst. In the next step, the questionnaire data were entered into the GAMS software and calculated and analyzed. A weight of 0.081 was calculated with the value of lε obtained for the thirty questionnaires, which indicates the stability and consistency of the calculated weights due to its proximity to zero. For a spatial analysis, the information layers of the indicators were first digitized and edited in the GIS software, and the significance coefficient calculated by the BWM method was multiplied by each of the indicators through conversion of the information layers into a raster and their classification. Using the weighted sum, the indicators were then combined for measurement of livability in the old and new parts of Urmia.
Results and Discussion
The calculations of the weights of the twelve indicators in the Gomez software indicates that the highest weight concerns the average land price indicator, with a significance coefficient of 0.169, and the lowest weight pertains to the area covered by sewage, with 0.015. The average value of λε obtained for the thirty questionnaires was 0.081, which indicates the stability and consistency of the calculated weights due to its proximity to zero.
Conclusion
The results of combining the twelve livability indicators for the old part of Urmia show that 2% of this part lies in the zone with very low livability, 13% in low livability, 32% in medium livability, 35% in high livability, and 18% is in very high livability. In the new part of Urmia, 7% lie in the zone with very low livability, 21% in low livability, 39% in medium livability, 29% in high livability, and 4% in very high livability. Furthermore, livability is better in the old part than in the new part based on the indicators of access to the main thoroughfares, average land price, population density, access to sports and recreational use, access to medical use, access to academic and cultural use, access to commercial use, number of literate people, and number of employees. On the other hand, livability in the new part is in good conditions compared to that in the old part based on the indicators of building quality, area covered by sewage, and access to green space use.
