Experimental Investigation on the Thermo-Mechanical Properties of Pre-Heated Wood Concerning Bending

The test report from the Technical University of Munich (TUM) investigates the thermo-mechanical properties of pre-heated wood under bending as part of a research project on wood behaviour in fire conditions, in collaboration with ETH Zurich and TALTEC University, aiming to revise design methods in EN 1995-1-2. The study involved preparing spruce and fir specimens, heating them to temperatures ranging from 20 °C to 240 °C, and testing their bending strength and modulus of elasticity in three scenarios: immediately after heating, after cooling for 24 hours, and after re-moisturisation for 28 days. The results showed that the bending strength decreases with rising material temperatures. Only a small recovery is noticeable at temperatures above 100 °C due to loss of wood moisture. In the cold and re-moisturised scenarios, the bending strength regains its full potential. The modulus of elasticity behaves similar to the bending strength.