Performance-Based Role of Structural Segmentation and Fire-Rated Expansion Joint Interfaces in Fire-Induced Damage Localization and Postfire Serviceability

Abstract

Passive fire safety has traditionally been addressed in terms of compartmentalization and the fire resistance of individual structural elements. However, facility-scale fire performance depends not only on material resistance but also on the continuity and interaction of structural segments. Expansion joints, often used to accommodate thermal and differential movement, are not fire-resisting elements by themselves; fire performance at these interfaces is provided by fire-rated joint systems and adjacent fire-resistant assemblies. When integrated with such systems, they can function as system-level segmentation interfaces regulating the spatial spread of fire-induced damage. This study investigates the performance-based role of expansion joints, as part of integrated structural segmentation systems, when used in conjunction with appropriate fire-resistant vertical assemblies (e.g., shear walls, partition walls), in limiting fire spread, controlling the distribution of structural damage, and improving postfire serviceability. A qualitative comparative analysis of documented fire cases was conducted to examine how structural compartmentalization affects fire behavior and salvage feasibility. To support the structured comparison, a simplified semiquantitative performance index framework was developed, incorporating indicators of damage localization potential, structural damage severity, and postfire serviceability. The framework employs an interpretive mapping approach of qualitative observations into normalized index values. The findings indicate that expansion joints contribute to fire performance primarily through enabling structural segmentation and, when properly protected, maintaining interface integrity, rather than directly enhancing fire resistance at the material level. Partitioned configurations demonstrate improved capacity for selective repair, phased reconstruction, and functional continuity following fire incidents. The proposed framework repositions expansion joints within the broader context of segmentation-based fire performance, highlighting that fire performance is governed by the combined action of structural partitioning and fire-rated interface systems rather than expansion joints in isolation, thereby enhancing plant integrity and postincident operability.