Shear modulus of old timber

Interest in both the time effect on the timber mechanical properties and the reuse of old solid timbers has prompted many research works since the 1970s, mainly focusing on evaluating bending strength (MOR) and stiffness (MOE). However, only few studies have investigated the effect of aging on shear modulus (G). In this work, transverse vibration test is used to calculate G and MOE of over 80 old timber beams. The MOE/G ratio and the relationship between G and different timber features are investigated. The main outcome of the research confirms that the MOE/G ratio is around 20, close to the value reported in literature for new solid timber. No relationship exists between G and MOE (r²=0.07) or between G and other timber features. When density and knots are used as predictors in a multiple regression model, the G rediction improves (r²=0.22). This work confirms that G is not affected by the age of timber.