Analysis of building structures subjected to electric vehicle fires

Electric vehicles (EV) are becoming increasingly popular worldwide due to environmental concerns. EV fires have been reported during charging process in some circumstances, but firefighting with water is ineffective due to the lithium battery . Particular attention must be paid to building basements . To analyze the safety of buildings to EV, the purpose of this research is to better understand the temperature field and mechanical damage in horizontal and vertical element reinforced concrete (RC) structures exposed to EV fires, and compare them to the ASTM and ISO curves (used in various standards for fire-design of RC members). The analysis was conducted using CFD and FEA thermal models. The first was used to define the temperature in an EV fire and was supported by experimental results from the literature. The second model was used to characterize the temperature field in the horizontal and vertical structural members , using real-scale experimental tests carried out by the authors to validate the model. The results suggest that the EV fire is more severe than standard (ST) in the first 45 min. However, vertical RC members are safe in an EV fire if they are designed according to ST curves, but horizontal structures are unsafe as they lose their bending capacity and thermal insultation before. Horizontal structures exposed to EV have about 10 min less fire resistance than would be expected in ST fires. • Reinforced concrete (RC) structures of buildings designed according to the standardized fire curves ASTM E119 and ISO 834 are not safe in case of a fire of electric vehicles (EV). • Vertical elements (columns) are safer in relation to horizontal elements (slabs and beams). • The heating generated by an EV fire is critical in the period between 15 and 30 min, i.e., in the initial phase of the EV fire. • It is estimated that the FRR (fire resistance rate) of RC slabs heated with EV is about 10 min lower than the FRR expected according to ISO and ASTM.