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Development of An Adjusted Blockage Index for Seismic Resilience Analysis of Urban Road Networks: A Case Study of Tehran’s District 16
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Tahereh Ghaemi Rad *   |
| Geoinformation Tech. Center of Excellence, Faculty of Geomatics Eng, K. N. Toosi University of Technology, Tehran, Iran. |
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Abstract: (350 Views) |
Objective: Urban road networks serve as critical lifelines in emergency response during disasters; however, their functionality is severely threatened by building collapses caused by earthquakes. This study develops a Geographic Information System (GIS)-based framework to assess the probability of route blockage within the urban road network of District 16 of Tehran, an area characterized by high building density and deteriorated urban fabric.
Method: A modified road blockage index (BIadj) was developed by integrating four morphological indicators—slope (up to 69.95%), road width (minimum 0.24 m), building height (up to eight stories), and network connectivity (edge-to-node ratio)—with the structural stability of the surrounding urban fabric. To account for structural deterioration, weighting coefficients ranging from 1 to 2 were assigned to stable, unstable, and deteriorated urban fabrics.
Results: The results indicate significant spatial variation in risk distribution. While major arterial roads remain relatively resilient, approximately 54% of the study area consists of vulnerable urban fabric, and 77% of the total road length is located within unstable zones. By applying a critical threshold (BIadj > 0.5), the model identified 13 high-risk corridors leading to the isolation of 19 residential parcels. Demographic analysis of these isolated areas, based on the 2016 census data, revealed that 72 residents—including 17 highly vulnerable individuals—could potentially become trapped due to route blockage, thereby losing access to emergency services during an earthquake. Visual validation using high-resolution satellite imagery further confirmed the hazardous blockage index values in these hotspots, particularly in the Naziabad neighborhood of District 16, Tehran.
Conclusions: The proposed blockage index provides an operational roadmap for urban planners to prioritize structural retrofitting measures and optimize emergency access routes. The findings demonstrate that integrating road morphology with structural vulnerability assessment can shift disaster management approaches from generalized evaluations toward targeted spatial interventions aimed at enhancing urban resilience against earthquakes. |
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| Keywords: Seismic Resilience, Blockage Index, Urban Road Network, Emergency Access, Geo-Spatial Information System |
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Full-Text [PDF 1555 kb]
(89 Downloads)
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Type of Study: Research |
Subject:
Special
Received: 2026/03/14 | Accepted: 2026/03/14 | Published: 2026/06/10
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