Detection and analysis of an eave purlin of the timber building eroded by carpenter bees based on computed tomography

Abstract

To explore the harm of carpenter bee nests to timber buildings, an eave purlin of Wu’s house, the seventh batch of national key cultural relics in China, was taken as the research object. A CT (computed tomography) device was used to collect the projection data of wood components, and VGSTUDIO MAX3.2 software was used to reconstruct multiple transverse sections, radial sections, tangential sections, and 3D (three-dimensional) images of an eave purlin. The results showed that carpenter bees eroded a timber building randomly, but they usually nested along the length of eave purlin. The wood in the middle of an eave purlin is more vulnerable to carpenter bees than the end. Carpenter bee nests are usually not connected, and the volume of nests accounts for 3% to 4% of the eave purlin. The eave purlin is applied with an orientation and a torsion force. The position of the maximum hot spots of the stress occurs at holes and the large cracks, indicating that carpenter bee nests have a great impact on the mechanical properties of timber buildings. The research results of this paper provide reference for the safety evaluation and preventive protection of timber buildings.