Structural health monitoring of glulam structures: analysis of durability and damage mechanisms

Abstract

In today’s environmental context, the use of glulam or Glued Laminated Timber (GLT) as an alternative to conventional building materials could reduce the carbon footprint of engineering structures. However, this material is sensitive to outdoor exposure with moisture content variations inducing internal stresses and cracks and high moisture content increasing the risks of decay. This study therefore focuses on the development of a protocol to evaluate the effect of climatic conditions on the mechanical performance of the material. For this purpose, GLT samples were equipped with embedded sensors. Moisture and deformation sensors can accurately track wet-dry (W/D) cycles and their effects on deformation at adhesive joints. Samples are stored outdoors and mechanical tests are carried out after 6 months of aging. The results show an average reduction in flexural strength of about 10% compared to unaged specimens. Shear tests on the adhesive joints show a decrease in strength of more than 20%. The study of the fracture mechanisms also indicates a link between the type of fracture and the aging conditions of the specimens. These tests also validated a monitoring protocol that will allow, in the long term, to evaluate the impact of these cycles on the mechanical performance of GLT.