THE INVESTIGATION OF THE STRENGTH REDUCTION FACTOR IN PREDICTING THE SHEAR STRENGTH

Design codes propose to restrict the nominal probability of failure within specific target
structural reliability levels using a load factor and a strength reduction factor. In the current
ACI318 Code, the strength reduction factor varies from 0.65 to 0.90, and the value considered
in predicting the shear strength equals to 0.75. In this study, the change in the strength
reduction factor in predicting the shear strength according to ACI318 has been investigated
for different coefficients of variation of concrete compressive strength by using the first-order
second moment approach, and the strength reduction factor is proposed for the target values
of failure probability.