S–N curves for fatigue of bond in reinforced concrete structures under transverse tension

In reinforced concrete construction, design verifications for the fatigue of reinforcing steel and concrete are required separately. In this manner, the fatigue behaviour of the bond between steel and concrete was not taken into consideration. Longitudinal cracking along the reinforcing bar due to transverse tension reduces the loading capacity as well as the fatigue strength. By means of comparing current design codes regarding the fatigue of concrete and reinforcing steel, an appropriate approach is being looked for to represent the fatigue of the bond. The S–N curves for the bond, which resulted from pull-out tests, were set in relation to S–N curves for the fatigue of reinforcing steel. It becomes evident how the fatigue of bond resistance due to increasing transverse tension load gains in importance compared to the fatigue of reinforcing steel.