Towards enhancing the post-peak performance of glued-laminated timber beams using multi-directional fibre reinforced polymers.

• Unretrofitted glulam beams have little to no significant post-peak resistance. • Multi-directional GFRP localized damage and significantly enhanced the performance. • Ductility ratios ranging 2.3–3.6 are obtained using multidirectional FRP fabrics. • An average increase in wood ultimate tensile failure strain of 1.21 is observed. • An approach that considers strain rate dependency and empirical knowledge is proposed. An experimental program, investigating the potential of using multi-directional fibre-reinforced polymers (FRPs) as a strengthening option for glulam beams when subjected to blast loading, was undertaken. A total of ten different retrofit configurations were investigated and compared to the behaviour of unretrofitted glulam members. In general, the use of multi-directional GFRP contributed to significant performance enhancement, where ductility ratios in the range of 2.3–3.6 were obtained. The use of bidirectional GFRP fabrics localized the damage in the wood section to a small area, and provided confinement which helped delay the failure of the retrofitted specimen. The FRP fabrics also contributed to an increase in wood ultimate tensile failure strain. A two-step approach was proposed to predict the resistance function of the retrofitted specimens. The model predicted the peak resistance and deflection at peak resistance reasonably well. The approach was able to predict the ultimate failure deflection when the experimental ductility ratios were used. An approach for design using a lower-bound ductility ratio was proposed. [ABSTRACT FROM AUTHOR]