Seismic Retrofitting of Existing Structures: A Comprehensive Review of Techniques, Performance, and Challenges

Abstract

The increasing frequency and intensity of seismic events worldwide have highlighted the urgent need to enhance the structural resilience of existing buildings, particularly in earthquake-prone regions. This paper presents a comprehensive review of seismic retrofitting techniques, categorizing them into global, local, and innovative approaches. It evaluates the historical context of seismic disasters, the evolution of retrofitting standards (FEMA, IS 13935, Eurocode 8), and the classification of buildings based on risk. Analytical methods such as pushover analysis, time-history simulations, and fragility curve assessments are discussed in relation to structural performance parameters like ductility, base shear capacity, and inter-story drift. A comparative analysis of different techniques is conducted based on cost, feasibility, and performance across varied structural systems. The study also identifies key challenges—financial constraints, occupancy disruption, regulatory gaps—and offers future recommendations, including performance-based design, smart monitoring integration, and policy-level interventions for urban seismic resilience. The findings serve as a valuable resource for engineers, policymakers, and stakeholders seeking effective, scalable retrofitting solutions.