Post-Cracking Web-Shear Response of Hollow Core Slabs with Low Steel Fiber-Volume Fractions

This paper investigates the effectiveness of steel fibers in low dosage or volume fraction, 0.17% and 0.34%, as a mean to enhance the post-cracking web-shear strength of precast hollow-core slabs. The experimental campaign includes 26 specimens, 200 and 300 mm thick, tested in three series. Series I and II investigated the influ-ence of fiber-volume fraction. Series III focused on evaluating the interdependency between the prestressed strand transfer length and post-cracking web-shear strength. The shear performance was assessed in terms of: 1) post-cracking strength; 2) toughness index; and 3) crack width. The test results showed improvements in all three performance indexes: post-cracking web-shear and toughness indexes increased by up to 90% and 50%, respectively, at three times the cracking deflection, while crack widths decreased by down to 80% when using 0.34%. Despite the increase in the post-cracking web-shear strength, no increase in the peak shear strength was observed.