Advanced Structures & Composites Center

Published: 2000

Publication Name: Wood and fiber science

Publication URL: https://wfs.swst.org/index.php/wfs/article/download/1879/1879/0

Abstract:

This study focuses on the development and calibration of a numerical method for modeling creep deformations of glulam beams strengthened on the tension side with fiber-reinforced polymers (FRP). The results of an experimental investigation on the creep of twelve, 7-m-long FRP-reinforced Douglasfir and western hemlock glulam beams are briefly presented. The experiments, conducted in a sheltered environment with controlled temperature and uncontrolled relative humidity, demonstrate that, although FRP-reinforced beams can support significantly larger loads than unreinforced beams, they do not exhibit increased relative creep. A numerical model based on layered moment-curvature analysis is developed, and a general solution strategy is detailed that permits the easy inclusion of nonlinear viscoelastic or viscoplastic material properties. A viscoelastic constitutive model is proposed for the wood that accounts for experimentally observed mechano-sorptive creep effects, and is implemented within the framework of the proposed numerical scheme. The model parameters are fitted to the unreinforced specimen test results, and the model is then shown to accurately predict the observed relative creep displacements of the reinforced specimens. Parametric studies are conducted that clearly demonstrate the effectiveness of FRP tensile reinforcing in reducing creep deformations in glularn beams.