Flexural and shear behaviour of ancient wooden beams: experimental and theoretical evaluation

In this paper the results of a wide experimental campaign on the structural behaviour of ancient chestnut beams are presented. The beams were taken from the floor slab of an existing building, they being representative of the bearing structures of common historical buildings of many Mediterranean countries. Therefore, they were characterized by natural defects and degradation phenomena, which may have a significant effect on the evaluation of the load bearing capacity of the member. Four beams in actual dimension have been considered, which have been subjected to static bending tests, aimed at the evaluation of stiffness, strength, post-elastic behaviour and collapse mechanism. In the paper, the global influence of relevant defect patterns on the behaviour of these beams has been evaluated by comparing their overall behaviour with the actual material response obtained by compression, bending and shear tests on defect-free small specimens. The obtained results show that the simplified methods commonly used to evaluate the bearing capacity of wooden beams can be safely applied to ancient structural members as well, provided that adequate reduction factors for the shear resistance are considered.