Size effect on the shear failure of high-strength concrete beams reinforced with basalt FRP bars and stirrups

Six large-scale high-strength concrete beams reinforced with basalt fiber reinforced polymer (BFRP) bars and stirrups and three corresponding beams without stirrups were constructed and tested for shear failure under four-point bending. The main parameters considered were the beam effective depth (300, 500, and 700 mm) and the stirrup spacing. The test results indicated that the size effect on shear failure could not be eliminated completely, as the initial shear crack, shear crack width, shear resistant components analysis, strain in the BFRP stirrups, and normalized shear strength were still related to the beam depth. The ACI 440-15 strain limit of 4000 mu s could be relaxed with the condition that the serviceability requirement is satisfied. Furthermore, based on a collected database from the literature, an accurate and conservative equation was proposed to predict the FRP stirrup strain limit. The proposed equation includes the effects of all influencing parameters, which is more reasonable than the constant strain limit used by most design codes. (C) 2019 Elsevier Ltd. All rights reserved.