This study is part of a larger research work aimed to study the effects of fiber
content, fiber type (corrugated shape and hooked-end), amount of web reinforcement and axial
compression stress, on the shear behavior of high strength fiber reinforced concrete (HSFRC)
beams. To the author’s knowledge, the effect of applying axial compression forces, to the HSFRC
beams, has not yet been studied. Nineteen simply supported HSFRC beams were subjected to axial
compression forces and tested under two-point vertical loading for three values of shear span to
depth ratio. It was found that the shear strength of beams subjected to axial compression stress
level equals 0.1, is higher than that in the literature for beams tested without applying axial stress
by a range of 22% -98%. Increasing the axial compression stress level to 0.2 led to an increase in
the first crack load, ultimate load by 24% and 10%, a reduction in the deflection by (19-30%),
compared with those subjected to axial compression stress level equals 0.1. In addition, a
combination of web reinforcement and fibers resulted in a significant increase in the cracking and
ultimate loads by 123 and 59%, respectively, over those of the reference beam. A new formula is
proposed for predicting the experimental shear strength of HSFRC beams subjected to axial
compression forces. The results obtained by the proposed formula are in better agreement with the
test results when compared with the predictions based on the empirical equations proposed by
other investigators. |
