Slip behaviour at cyclic pullout tests under transverse tension

In case of a reinforced concrete structure being exposed to bond stresses that transfer great forces, a relative displacement between reinforcing bar and concrete occurs. The slip is an important parameter in order to evaluate the quality of the bond concerning repeated pullout loads. A rapid slip increase is caused by bond weakening due to longitudinal cracks resulting from transverse tension. Within the bond area the slip is not uniformly distributed along the reinforcing bar. It is still unexplained how far fatigue and transverse tension affect the distribution. This paper focuses on the development of the slip curve under repeated loading and transverse tension. Results from cyclic pullout tests were applied and particularly the slip difference between the loaded and unloaded end of the pullout bar was investigated. It could be observed that both an increase in load cycles and transverse tension did not cause an appreciable change in slip difference.

► In pullout tests, the slip is not uniformly distributed along the reinforcing bar.
► Repeated loading has no influence on the slip difference development between loaded and unloaded bar end.
► Longitudinal cracks due to transverse tension affect the absolute slip values but not their difference.