20.500.12556/DiRROS-23009 Investigating the thermal penetration in structural timber elements exposed to natural fires This study investigates fire-induced charring and thermal penetration in structural timber elements exposed to natural fire conditions, with a focus on the critical role of the cooling phase. A simplified 1D heat transfer model, based on Eurocode 5 temperature-dependent material properties, is implemented to simulate the thermal response of timber members subjected to Eurocode parametric fire curves. The analysis quantifies the char depth (300 °C isotherm) and the zero-strength layer, using both temperature-based (80-300 °C and 120-300 °C) and reduced mechanical properties approaches (tension and compression). Results show that, while the char depth predominantly develops during the heating phase, the zero-strength layer continues to grow during cooling, often reaching a thickness comparable to the char layer. The effective char depth (char depth + zero-strength layer) typically reaches its maximum towards the end of the cooling phase, representing the most critical condition for load-bearing capacity. The most severe conditions arise in low ventilation and high fuel load scenarios, characterised by long-duration fires rather than the highest temperatures. The findings highlight the need to explicitly consider the cooling phase in performance-based fire design for timber structures. timber structures fire safety charring zero-strength layer cooling lesene konstrukcije požarna varnost ogljenitev plast brez trdnosti ohlajanje true false true World Conference on Timber Engineering Angleški jezik Slovenski jezik © WORLD CONFERENCE ON TIMBER ENGINEERING 2025 (WCTE 2025) Neznano 2025-07-16 08:13:59 2025-07-16 08:34:48 2025-10-24 03:52:56 0000-00-00 00:00:00 2025 0 0 str. 3674-3683 0000-00-00 Zaloznikova Objavljeno NiDoloceno 0000-00-00 0000-00-00 2025-06-01 624 10.52202/080513-0450 241463811 239752963 https://doi.org/10.52202/080513-0450 0 11a17ee5-620c-11f0-9bb7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=33660 RAZ_Lucherini_Andrea_2025.pdf RAZ_Lucherini_Andrea_2025.pdf 1 778543A6439ABCF343F23E77ADFAD200 d7e518b285fcda3cd63fa929b06820438636097934973e859bb258e2b27918bd f341b5dd-620e-11f0-9bb7-001a4af901a5 https://dirros.openscience.si/Dokument.php?lang=slv&id=33661 Zavod za gradbeništvo Slovenije 0 0 0