Development of an equation calculating young s modulus remaining ratio with temperature and moisture content within wooden members exposed to fire heating

Young's Modulus of wood is formulated as functions of temperature and moisture content for the assessment of mechanical performance of wooden members exposed to fire heating. Parameters are determined for 5 tree species common for construction by regression analysis with results of bending tests for temperature between 20°C and 250°C, moisture content between 0% and 180.5%. Differences of temperature dependence of Young's Modulus between tree species was small at bone-dry state, but large at high moisture content. Young's modulus remaining ratio at high moisture content decrease to 0.57 in Cryptomeria japonica, 0.35 in Zelkova serrata even under 100°C.