Influence of Splitting Cracks on Tension Stiffening

The authors report on the influence of splitting cracks on tension stiffening of reinforced concrete tension members. The effect of different sizes of reinforcing bars, ranging from Number 10 to Number 30, on the formation of splitting cracks was examined. Two different concrete strengths, 35 and 90 MPa, were used in the specimens to study the influence of concrete strength on tension stiffening. Although it is well-known that the development of transverse cracks reduces the tension stiffening, the presence of longitudinal splitting cracks was found to significantly alter the tension stiffening. Investigators also learned that the concrete cover-to-bar diameter ratio is a useful indicator for determining the extent of concrete splitting with a decrease in the concrete cover-to-bar diameter ratio resulting in more significant splitting cracks. A factor related to the concrete cover-to-bar diameter ratio was used to modify a tension stiffening expression to account for the important effect of longitudinal splitting cracks.