ABSTRACT
Rapid expansion of urbanization has led to the increased vulnerability of infrastructures to bush-fires and wildfires. Australian, bridge inspection manuals recommend a level 3 type of investigation as a post-bushfire bridge evaluation. Fire/structure interactions are dependent on fuel quantity, geometry, fuel characteristics, ambient conditions and structural characteristics. Given the scant research on wildland urban interface (WUI) fire, this research presents a numerical modeling approach of WUI fire with Fire Dynamic Simulation (FDS) software, utilizing the parallel computing facility. A domain size of 56m length 10m wide and 25m height with a uniform 200mm mesh resolution, that includes different fuel geometries and a bridge structure, were modeled in the analysis. The maximum temperature of the 12mm thick steel web and concrete bottom surface are around 350C and 115C respectively. Initial results show that there is no considerable strength degradation nor concrete cracking nor spalling. However, some dehydration of the concrete and reduction of Young’s modulus in steel by 25% was observed. However, the strength degradation of steel up to 400C is limited. Further research is recommended to assess the cumulative effects on a structure when exposed to recurrent WUI fire events.
