Effects of Double-Arched Geometry and Tensile Strength on the Pullout Resistance of Fibers

This study evaluated the pullout resistance performance of a developed double-arched steel fiber. Pullout experiments were conducted to assess the resistance load, bond strength, and energy absorption capacity of the fiber according to the geometry and tensile strength of the fiber. Double-arched (DA) steel fibers demonstrated peak and residual resistance loads approximately 36-112% and 29-163% higher than hooked-end and single-arched steel fibers, respectively. The DA steel fiber also significantly increased the bond strength and energy absorption capacity by approximately 58-159% and 125-130%, respectively, compared to the hook-end and single -arched steel fibers. Moreover, the DA fiber exhibited a more significant increase rate in pullout resistance load, bond strength, and energy absorption capacity with increasing tensile strength. A prediction model was also developed to incorporate the influence of plastic bending and friction resistance on the pullout behavior of the DA fiber. The resistance loads and decreasing trend obtained from the prediction model exhibited a very close agreement with the experimental results.