Variable prestressing of FRP-reinforced glulam beams: Methodology and behavior.
Published: 2010
Gray, H.
Dagher, H. J.
Davids, W. G.
Nader, J.
Publication Name: Proceedings of WCTE 2010 Ð 11th World Conference on Timber Engineering, Trentino, Italy, Jun 20-24 (CD-ROM).
Publication URL: https://www.researchgate.net/publication/265267739_Variable_prestressing_of_FRP-reinforced_glulam_beams_Methodology_and_behavior
Abstract:
This paper focuses on the development and structural benefits of a novel method of prestressing GFRP-reinforced glulam beams that involves clamping the pre-tensioned GFRP to the glulam and releasing the pre-tensioning while the GFRP-wood bond line is still wet. After release of the tension forces at the ends of the GFRP tendons, full pre-tension remains in the middle third of the tendon because of mechanical friction between the GFRP and the clamping surface. The GFRP tensile force declines linearly from full tension at the third points to no tension at the ends, reducing shear and peeling stresses at the ends of the beam after adhesive cure and clamp release. The strength performance of prestressed GFRP-reinforced glulam beams was assessed through bending tests and cross-sectional analysis. The results of the tests showed a 38% increase in allowable bending stresses for the prestressed GFRP-glulam beams relative to the reinforced GFRP-glulam beams without prestress and an approximately 95% increase compared to unreinforced glulam beams. These results show that variable prestressing of GFRP-reinforced glulam beams shows significant promise for practical applications.