Extended Abstract
Introduction
 
Rapid urbanization in Iran has concentrated people and assets in cities while simultaneously amplifying the exposure of deteriorated urban fabrics to both natural and human-induced hazards. Roughly 13% of urban territories are classified as dysfunctional, accommodating over 15% of the national population, and many of these areas suffer from fine-grained parcels, substandard buildings, and narrow, discontinuous street networks that inhibit evacuation and emergency access. Within this context, the study aims to design and reorganize the deteriorated fabric of the Evin neighborhood in Tehran through a passive-defense lens, seeking to reduce multi-hazard risk while safeguarding social and cultural values embedded in the historic urban tissue.
 
Methodology
The research is applied in purpose and descriptive–analytical in method. Data were collected via field observation, document analysis, and expert consultation. Risk assessment follows the FEMA framework in which Risk = Asset Value × Threat × Vulnerability, enabling a comparable, matrix-based reading of risk levels across neighborhood units. Seven neighborhood blocks (as basic spatial units) were delineated, and the intensity of risk for each was computed against a set of relevant threats—including earthquake, intentional attacks on symbolic or critical assets, and civil unrest—then classified into low/medium/high categories. Indicator weights for the three components (asset value, threat, vulnerability) were derived using the Analytic Hierarchy Process (AHP), informed by expert judgement. The output is a block-by-threat risk matrix that pinpoints priority locations for intervention.
 
Discussion
Findings underscore the utility of a passive-defense–oriented regeneration strategy that couples physical upgrades with social and operational measures. Rather than viewing Evin’s deteriorated fabric solely as a liability, the approach recognizes embedded values and the necessity of risk-sensitive conservation—reducing exposure and fragility without erasing local identity. The framework operationalizes this through six complementary “systems,” each linking design decisions to specific risk drivers revealed by the matrix:

Mobility & Access: Targeted widening of key links to ensure emergency vehicle passage, reduce blockage from debris, and shorten response times; clarifying pedestrian–vehicular hierarchies to enable orderly evacuation.
Safety & Security: Functional lighting, continuous overlooking (“eyes on the street”), and landscape-based screening instead of blank, tall barriers; water run-off control and guaranteed rescue access corridors.
Social & Public Realm: Activation of semi-public places, support for community services (e.g., libraries, cafés), upgraded sidewalks (e.g., on Kachui Street) and safe pedestrian routes, and strengthening of landmark buildings (e.g., the Imamzadeh and hussainiya) to act as community support hubs during crises.
Land Use & Infrastructure: Rebalancing uses to place traffic-attracting functions at edges, relocating aging utilities to multi-purpose underground corridors, and provisioning for emergency water/energy and temporary shelter.
Urban Form & Fabric: Modular layouts aligned with local materials, reduced mutual overlooking among private open spaces, roof forms and orientations that mitigate blast or wave effects, and progressive adoption of networked grids to diffuse localized risk.
Passive Defense in Architecture & Urbanism: Recessed and elevated entries, rounded corners, deep-set vertical openings positioned in the upper third of walls with reinforced frames, partial earth-sheltering (basements), and preferably reinforced concrete structural systems; at the neighborhood scale, shelters and emergency depots, green “rings” (including roof gardens and terrace trees) for damping and concealment, plot consolidation, lower site coverage to enlarge open space, and wider streets with fewer cul-de-sacs to improve permeability and crisis management.

 
Results
 
By integrating FEMA’s asset–threat–vulnerability logic into a neighborhood-scale assessment, the study demonstrates a practical pathway to prioritize interventions in deteriorated fabrics such as Evin. The results show that risk is not uniformly distributed; it concentrates where critical functions coincide with structural and spatial weaknesses. A phased action plan is therefore recommended, beginning with (1) upgrading critical corridors and reducing dead-ends; (2) seismic strengthening and strategic relocation of utilities into underground corridors; (3) creating multi-purpose open spaces capable of hosting emergency shelter and operations; (4) implementing building-level passive-defense details (entries, openings, structural systems); and (5) formalizing resident participation in design and stewardship. Framed as risk-informed regeneration, the approach reduces human and economic losses while amplifying the neighborhood’s social capital and identity, positioning Evin as a replicable model for similar Iranian contexts.
Conflict of Interest
Authors declared no conflict of interest.
 
Acknowledgments
 We are grateful to all the scientific advisors and participants in the research.