Qualitative Assessment of the Vulnerability of Buildings in Roshdiyeh Town of Tabriz in Terms of Resilience During Earthquakes

Introduction: Tabriz, as one of the major metropolises in Iran with a long history of destructive earthquakes, is a prominent example of cities prone to seismic hazards due to its location on active fault lines. This city, particularly in its northern and eastern areas, lies on the North Tabriz Fault. At the same time, rapid urban growth, high population density, and unsustainable developmenthave exacerbated challenges related to earthquake risk management. One of the key areas in Tabriz with high seismic importance is the Roshdiyeh neighborhood. As a developed area with diverse urban structures, Roshdiyeh features a mix of concrete, steel, and masonry buildings. However, a significant portion of these structures, especially masonry buildings, have not been adequately retrofitted, significantly increasing the seismic vulnerability of the region. This study's problem statement is based on the premise that many buildings in Roshdiyeh are highly vulnerable to moderate to severe earthquakes due to their location on the Tabriz fault. This vulnerability threatens the safety and lives of residents and could lead to socio-economic collapse and widespread urban disruptions. The lack of accurate and documented data on the vulnerability of buildings in the region adds further challenges for urban managers and planners in developing risk reduction and retrofitting policies.
Materials and Methods: This study employed an analytical-descriptive approach using the ARIA method to assess the seismic vulnerability of buildings in the Roshdiyeh neighborhood of Tabriz. The area was selected as the case study due to its location on the North Tabriz Fault and the diversity of its constructions. Data were collected through field observations, structural assessments, and completion of standard ARIA checklists. Variables such as soil type, structural system, building height, and plan irregularities were analyzed based on earthquake intensities of 7, 8, and 9 on the Mercalli scale, and a damage index (LR) was calculated for each building. Data analysis using statistical tools and GIS provided seismic vulnerability zoning maps for various earthquake intensities. The results indicate that masonry buildings without reinforcements showed the highest vulnerability, while concrete buildings with shear walls exhibited the least damage. Expert opinions from earthquake and structural engineering specialists validated the findings. This comprehensive study serves as a tool to identify seismic vulnerabilities and proposes solutions such as retrofitting buildings, adhering to construction standards, and planning for emergency response. It represents a significant step toward reducing earthquake risks and enhancing urban safety in Roshdiyeh, Tabriz.
Results and Discussion: The study found that masonry buildings without reinforcements exhibit the highest seismic vulnerability in Roshdiyeh, and they are likely to undergo total collapse in severe earthquakes (Mercalli 9). Steel buildings without bracing also demonstrated considerable vulnerability due to design flaws. Conversely, concrete buildings with shear walls performed well under seismic forces, showing the lowest vulnerability levels.
The analysis revealed that buildings with horizontal and vertical reinforcements, while better than unreinforced masonry structures, remain vulnerable to severe earthquakes and require retrofitting. Steel buildings with bracing showed better performance and lower damage indices. Seismic vulnerability zoning delineated a high concentration of vulnerable buildings in specific areas of Roshdiyeh, especially in older neighborhoods, constituting a substantial threat to life safety and property loss. The findings underscore the need for retrofitting masonry and steel buildings, adhering to seismic standards for new constructions, establishing emergency infrastructure in high-risk zones, and implementing precise planning to mitigate earthquake risks.
Conclusion: The study concluded that unreinforced masonry and steel buildings without bracing in Roshdiyeh, Tabriz, have the highest seismic vulnerability and face a high risk of collapse in severe earthquakes. In contrast, concrete buildings with shear walls demonstrated superior seismic performance attributable to their inherent ductility and lateral load-resisting system. The concentration of vulnerable buildings in densely populated areas creates serious challenges for crisis management. Retrofitting existing buildings, enforcing seismic standards, establishing emergency facilities, and urban planning are critical measures to reduce vulnerability. Emphasizing resilient structural design and sustainable development is essential to enhance the region's safety and resilience