Post Fire Assessment
Post-fire assessment follows the ISO 834 standard fire curve: damage is judged from peak fire temperature, duration and member type (column/beam/slab/wall); higher temperature and longer exposure mean worse damage, combined with 6 damage indicators.
<300°C：基本无损伤 | 300~600°C：强度下降 20~40% | 600~800°C：强度下降 50~70%
>800°C：严重损伤，强度丧失 70%以上；粉红色变色约 300~600°C，灰白色约 600°C+
400°C：屈服强度下降 30% | 500°C：下降 50% | 600°C：下降 70%
屈服变形/扭曲表明温度曾超 500°C，须重点评估
炭化深度估算：dc ≈ 0.6 × √t（t 为受火时间分钟），炭化速率约 0.6~0.8 mm/min
剩余截面须满足承载力要求
| Item | Formula / Note | Source / Standard |
|---|---|---|
| Concrete damage temp | 300 °C spalling; 600 °C −40% strength | GB/T 24335-2009 |
| Steel yield loss | Yield drops ≥400 °C, ~47% at 600 °C | ECCS Tech Note |
| Rebound re-test | Rebound discount 0.7–0.9 in fire zone | JGJ/T 23-2011 |
| Carbonation depth | Fire accelerates carbonation depth | GB/T 50344-2019 |
| Crack width | >0.5 mm through-crack = severe | GB/T 24335-2009 §6 |
| Assessment classes | A–D rating classes | GB/T 24335-2009 |
根据结构类型、火灾温度、持续时间和损伤迹象，评估火灾后构件损伤程度，输出五级安全等级与处理建议。