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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 *  |
| K.N. Toosi University of Technology |
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Abstract: (90 Views) |
Urban road networks are the lifelines of disaster response, yet their functionality is severely threatened by earthquake-induced building collapses. This study develops a GIS-based framework to assess path blockage probability in District 16 of Tehran, a region characterized by high structural density and old urban fabric. We propose an adjusted Blockage Index ( BIadj ) that integrates four morphological indicators, slope (reaching 69.95%), street width (minimum 0.24m), building height (up to 8 floors), and network connectivity (edge-to-node ratios), with the structural stability of the surrounding fabric. To account for structural decay, weighting coefficients (1.0 to 2.0) were assigned to stable, unstable, and old fabrics. The results reveal a stark spatial disparity in risk; while arterial roads remain resilient, approximately 54% of the district's area consists of vulnerable fabrics, and 77% of the total street length is situated within non-stable zones. Applying a critical threshold ( BIadj>0.5 ), the model pinpointed 13 high-risk corridors that would result in the isolation of 19 residential parcels. Demographic analysis of these isolated zones, based on the 2016 census, indicates that 72 individuals (including 17 high-risk vulnerable residents) would be effectively trapped and cut off from emergency services. Visual validation via high-resolution satellite imagery confirmed the precarious height-to-width ratios in these hotspots, particularly in the Naziabad neighborhood. This methodology provides urban planners with a high-resolution operational roadmap to prioritize structural retrofitting and optimize emergency access routes, shifting disaster management from general assessments to targeted spatial interventions.
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| Keywords: Seismic Resilience, Blockage Index, Urban Road Network, Emergency Access, Geo-Spatial Information System |
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Type of Study: Research |
Subject:
Special
Received: 2026/03/14 | Accepted: 2026/03/14
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