Experimental investigation of glued-laminated timber beams with Vectran-FRP reinforcement: Fid-Bau Portal

Experimental investigation of glued-laminated timber beams with Vectran-FRP reinforcement

Donadon, Bruno F. / Mascia, Nilson T. / Vilela, Ramon / Trautwein, Leandro M.

Highlights • This work investigated timber beams strengthened by Vectran-FRP reinforcement. • Vectran is a high-performance synthetic fiber whose application as reinforcement is little explored. • Reinforced glue-laminated timber beams from reforested wood of Pinus Elliottii are tested in bending. • Vectran fibers provides increase in the initial stiffness and the ultimate load. • The use of fibers changes the failure mode of the timber from brittle to ductile.

Abstract The growing interest in sustainable buildings has inspired the improvement of timber structures in the construction market. As a raw material, wood may present natural defects that can cause changes in its mechanical properties, such as strength reduction, as well as brittle failure under tension, which limit the application of this material in construction. In recent decades, synthetic fibers with high tensile strength are available as construction material, and research to evaluate the efficiency of synthetic fibers and adhesive composites as a reinforcement for glued-laminated timber beams has been carried out. This paper deals with an experimental study applying bending tests to glue-laminated timber beams made of Pinus Elliottii, a low-strength wood class originated from reforestation, and strengthened with fiber reinforced polymers of Vectran fibers and epoxy adhesive. A numerical procedure based on the finite element method is also developed to compare with experimental results. Vectran is a synthetic thermoplastic fiber with high mechanical properties, however, its potential application as reinforcement material in structural pieces is still poorly explored. The results obtained in this work demonstrated that the application of Vectran-FRP reinforcement to glued-laminated timber beams provided both an increase of 19.48 to 34.95% in elastic regime stiffness and of 7 to 40% in ultimate load, when compared with unreinforced similar beams. Numerical analysis adequately confirmed the experimental results on elastic behavior, while in the non-elastic phase it revealed a considerable difference. A reduction in the rupture coefficient of variation regarding the reinforced beams was also verified. In addition, the application of fibers as structural reinforcement changed the timbeŕs failure mode from brittle in tension to ductile in compression. The results show that Vectran fibers are mechanically efficient as reinforcement, with perspectives of application in construction.