Post-Earthquake Fire Performance of Strengthened Masonry and RC Structures: A Critical Review of Materials, Methods, and Knowledge Gaps

Post-earthquake fire (PEF) is a secondary hazard in which seismic damage to buildings, utilities and fire protection causes uncontrolled ignition and spread. PEF in unstrengthened reinforced concrete (RC) and steel structures has been increasingly studied, whereas the behavior of structures strengthened with fiber-reinforced polymers (FRP), textile-reinforced mortars (TRM/FRCM), ultra-high-performance concrete (UHPC) or engineered cementitious composites (ECC) under consecutive earthquake and fire is largely unknown. This review combines the seismic performance of strengthened RC and masonry elements, their behavior at elevated temperatures and the coupled PEF scenario. A knowledge matrix relates the available PEF evidence to the type of study. No experimental study has subjected FRP- or TRM-strengthened elements to the complete sequence of cyclic damage at realistic drift, fire under sustained gravity load, and residual-capacity assessment. In fact, the available tests reverse the sequence or omit one stage, and no PEF data exist for UHPC or ECC. Current codes treat seismic and fire actions separately. Six research gaps are identified, from sequential experiments to codification. Moreover, this review proposes measurable damage descriptors for the post-earthquake initial state and a set of verifications that designers can perform before PEF provisions are codified.