INFLUENCE OF SPLITTING CRACKS ON TENSION STIFFENING

This paper presents the influence of splitting cracks on tension stiff ening of reinforced concrete tension members. The effect of different sizes of reinforcing bars, ranging from No. 10 to No. 30 on the format ion of splitting cracks was investigated. Two different concrete stren gths, 35 and 90 MPa, were used in the specimens to investigate the inf luence of concrete strength on tension stiffening. Although it is well -known that the development of transverse cracks reduces the tension s tiffening, the presence of longitudinal splitting cracks was found to significantly alter the tension stiffening. It was found that the conc rete cover-to-bar diameter ratio (c/d(b)) provides a useful indicator for determining the extent of concrete splitting with a decrease in th e c/d(b) ratio resulting in more significant splining cracks. A factor related to the c/d(b) ratio was used to modify a tension stiffening e xpression to account for the important effect of longitudinal splittin g cracks.