# Post-Earthquake Fire Resistance in Structures: A Review of Current Research and Future Directions
## 8 Performance-Based Design for PEF
Evaluating PEF resistance--defined as the time the structure can resist collapse under fire after an earthquake--is crucial. Research indicates that PEF resistance significantly declines as the structure experiences earthquakes that push it to higher performance levels, such as LS or CP [66]. Several studies highlight the importance of considering the following factors:* Fire scenarios: Different fire scenarios, including those involving fire spread between compartments or across floors, can significantly affect PEF resistance [66; 72; 75]. For instance, research shows that fire resistance decreases when fire spreads rapidly between floors compared to scenarios with slower spread rates [75]. * Structural irregularities: Buildings with vertical irregularities, such as variations in stiffness or mass distribution across floors, are more vulnerable to both earthquakes and PEFs. For example, studies on steel frames have shown that irregular frames often experience a more significant reduction in fire resistance under PEF conditions than regular frames [71]. * Performance level: The fire resistance of a structure is influenced by its design performance level. Structures designed for higher performance levels, such as LS or CP, may experience more pronounced reductions in fire resistance after an earthquake compared to those designed for lower levels like IO [66]. Despite significant progress in understanding and modeling PEF behavior, further research is crucial for developing more accurate and reliable performance-based design methods. Key areas for future research include the following:  
* Expanding the PEF ignition model: Current models often focus on a limited number of ignition causes, such as gas pipeline failures. A more comprehensive understanding of ignition sources and their likelihood following earthquakes is essential [15]. * Enhancing PEF fragility databases: Fragility curves, which describe the probability of exceeding a certain damage state for a given hazard level, are essential for performance assessment. However, data on PEF fragility, particularly at the structural system level, are currently limited. Expanding this database is critical for improving the accuracy of performance evaluations and facilitating more informed decision-making in PEF-prone areas [15]. * Investigating the impact of earthquake damage on concrete behavior at high temperatures: Concrete, a commonly used building material, exhibits complex behavior at elevated temperatures. Understanding how earthquake-induced damage, such as cracking or spalling, influences concrete's thermal and mechanical properties is crucial for accurately predicting PEF resistance [65]. * Developing practical design tools: The complexity of PEF analysis often requires specialized software and expertise. Developing more user-friendly tools that integrate PEF considerations into the design process would facilitate broader adoption of performance-based PEF design principles [15]. By addressing these research gaps and incorporating the findings into performance-based design guidelines and codes, the resilience of buildings in earthquake-prone regions can be significantly enhanced, reducing the risk of post-earthquake fires and improving overall community safety.