Post-earthquake fire performance analysis fire doors in tall buildings

Abstract

Seismic excitations prior to a fire incident can cause damage to passive fire safety systems such as fire-rated doors, posing a high level of risk for the fire protection of the residents and building property. Seismic cracks on corners and joints, as well as lateral distortions, can widen the clearances between the door leaf and its frame, resulting in the fire door set being ineffective in preventing the rapid spread of smoke and flame. This is likely to render the means of egress inoperable and compound escape times in a fire hazard, especially in heavily occupied tall buildings. Although some building codes require periodic inspections for fire doors not to surpass the allowed clearances, no specification for the technical investigations for potential damages to these devices after an earthquake is provided. In the scope of this research, the earthquake and post-earthquake fire performance of fire door specimens were examined through the numerical and experimental stages. A 40-story tall residential building was modeled and designed. The structural model was subjected to nonlinear time history analyses to determine maximum inter-story drifts at various possible fire door locations on the typical floor plan. To determine damage states of the fire door assemblies, one-way static and displacement-controlled quasi-static reversed cyclic loadings were carried out by employing the maximum drift demands obtained in the numerical analyses. Tested and damaged 90-minute-rated fire doors were then exposed to the fire-resistance rating test to examine whether they would be capable during their standardized time of resistance. However, the resultant earthquake-induced damage predominantly caused up to 70% of the reduction in their fire-resistance rating. This study primarily demonstrates that fire doors, particularly those in tall buildings, should be inspected promptly for repair or replacement based on the extent of damage caused by moderate to major earthquakes.