| Abstract: |
Earthquakes continue to expose a persistent gap between the seismic demand imposed on the built environment and the capacity of buildings constructed before modern seismic codes were enforced. This review synthesizes three decades of research on the seismic vulnerability assessment and strengthening of existing multistorey buildings, drawing on empirical, analytical, and data-driven approaches reported in the literature. The paper traces the evolution of assessment methodology from first-generation rapid visual screening procedures, through mechanics-based tools such as pushover analysis and fragility curve construction, to the recent emergence of machine-learning-assisted vulnerability classification. It also reviews the principal strengthening techniques applied to deficient reinforced concrete and masonry stock, including concrete and steel jacketing, fibre-reinforced polymer and textile-reinforced mortar overlays, base isolation, and supplemental damping, weighing their structural effectiveness against cost, disruption, and durability concerns. Particular attention is given to configuration-driven weaknesses common in multistorey construction, notably soft and open ground storeys, short-column effects, plan irregularity, and pounding between adjacent blocks, which recur across case studies from India, Italy, Turkey, and other seismically active regions. A structured methodology guided the literature selection and classification underlying this review. The critical analysis that follows identifies where assessment methods diverge in accuracy and practicality, and where retrofitting research remains fragmented across material types rather than integrated at the building-system level. The review concludes that combining rapid screening for prioritization with performance-based assessment for design, supported by increasingly capable data-driven tools, offers the most credible path toward large-scale seismic risk reduction in existing multistorey building stock, though data scarcity and regional code disparities remain unresolved obstacles. |
