Fatigue Behavior of Reinforced Concrete Haunched Beams without Stirrups

In this paper, results of fatigue tests on reinforced concrete haunched beams without stirrups are presented for the first time. Two types of failure modes have been obtained, either due to fatigue of the reinforcement or due to shear fatigue. In addition, progressive increase of deflections with load cycles was measured. An analysis of tests is carried out in terms of the consequences of fatigue loading on ultimate strength and serviceability of reinforced concrete. Regarding fatigue strength, the limitations of existing models are shown and discussed. Regarding serviceability, it is shown that deflections are even higher than those theoretically obtained by the fully cracked member. This is due to development of shear deformations, cyclic creep, and negative tension stiffening during unloading stages.