Creep tests on notched beams of silver fir wood (Abies alba),
Résumé
The goal of the experimental study is to understand the impact of a high initial moisture content on the mechanical behaviour of silver fir timber. Silver fir accounts for 8% of the French forest and is appreciated by carpenters for its mechanical properties. However, drying this type of wood is a sensitive issue due to the presence of water pockets in heartwood and a high average initial moisture content. This paper presents the core of the study: creep tests in outdoor sheltered conditions, on notched beams having different initial moisture content. A batch of 30 beams from local silver firs has been characterised through (i) dynamic bending and compression, (ii) basic density measurements and (iii) static 4-points bending until failure on representative beams. Based on these preliminary tests, groups of four beams having similar mechanical properties but different initial moisture content were defined. Two groups were loaded in 4-points bending at the beginning of May 2021. Climatic (temperature, relative humidity) and mechanical parameters (central deflection, shrinkage/swelling, fracture initiation and propagation) were monitored. The first results show a wide variety of initial dynamic properties and moisture content. Consequently, the central deflection measured during the creep tests had different evolution depending on the beam. The result of the still on-going campaign will be analysed and presented in detail.