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The results of an experimental program investigating the dynamic increase factors of light-frame wood stud walls under blast loading are presented in this paper. A total of 20 walls with two different sheathing types and thicknesses were tested to failure under static and dynamic loading. The study found that the observed failure mode for both static and dynamic loading was flexure; however, a difference in the type of flexural failure was observed. Average increase factors of 1.40 and 1.18 on the resistance and stiffness, respectively, were found. A detailed literature review combined with the test results from the current project yielded a strong correlation between the increase in strain rate and the relative increase in strength and an equation relating the dynamic increase factor (DIF) on the resistance to strain rate was proposed for strain rates in the ranges of 1.67-1.65 x 10³s-1 [ABSTRACT FROM AUTHOR]

• Unidirectional GFRP improves the behaviour of studs and light-frame walls. • Simple tension GFRP reinforcement did not increase the ductility (i.e., brittle). • U-shaped GFRP reinforcements resulted in ductility ratios ranging 1.4–3.9. • Weaker specimens experienced greater increases when reinforced with GFRP. • Four GFRP reinforced walls were subjected to simulated blast loading. An experimental program was undertaken to investigate the flexural performance of forty-eight unreinforced and glass fibre-reinforced polymer (GFRP) reinforced Spruce-Pine-Fir No. 2 grade individual wood studs. In general, it was found that the GFRP contributed to reducing the damage region, especially when both reinforcement and confinement were utilized. The simple tension reinforcement did not provide any significant improvement to the post-peak behaviour and resulting in a brittle failure, similar to that observed in the unreinforced studs. Other reinforcement options, particularly those consisting of U-shaped reinforcement on the tension face with and without confinement, significantly increased the average flexural strength and stiffness of the stud by a factor of 2.4 and 1.8 times those obtained in the unreinforced studs, respectively. Significant ductility ratios, in the range of 1.4–3.9, were also observed in these reinforced configurations. Weaker specimens experienced greater increases in strength and reduction in variability when reinforced. Based on these observations, six full-scale light-frame stud walls reinforced with FRP were tested dynamically under simulated blast loading. The results showed that the walls reinforced with FRP performed better and had relatively less damage while dissipating, on average, twice the energy dissipated by the unreinforced walls. The observed failure modes of the reinforced walls were consistent with the static failure modes of the individual reinforced studs. [ABSTRACT FROM AUTHOR]

• 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]

This paper presents the results of an experimental program, where a total of eight retrofitted walls were subjected to blast loading, simulated by shock waves using the University of Ottawa's shock tube. Four different external retrofit options were considered and their behavior in terms of failure mode, stiffness, and strength were documented. Nonlinear single-degree-of-freedom (SDOF) modeling was performed using material models developed specifically for each retrofit. In general, good agreement was found between the predicted level of damage and calculated displacement using the model and the measured behavior. The study shows that a significant increase in stiffness and strength can be achieved. [ABSTRACT FROM AUTHOR]