Description
Concrete structures often face unforeseen challenges, whether from degradation or unexpected actions, requiring innovative strengthening techniques to extend their lifespan. In the last decade, shape-memory alloys (SMAs) have gained significant attention in structural engineering owing to their unique ability to recover from deformation, attributed to the shape-memory effect (SME). When constrained, SMAs can act as prestressing reinforcement, generating recovery stresses upon activation (heating and cooling). Among the various SMAs, iron-based SMAs (Fe-SMAs) have demonstrated exceptional potential for structural strengthening. Nonetheless, recent research has shown that Fe-SMA reinforcing bars may experience losses in recovery stresses when subjected to semi-cyclic loading.
This paper presents the results of an experimental campaign focused on assessing the impact of semi-cyclic loading on concrete elements reinforced with Fe-SMA rebars. The reinforced concrete test specimens were subjected to semi-cyclic loads before and/or after the activation of the Fe-SMA rebars. The preliminary findings show the effectiveness of Fe-SMA rebars as prestressing reinforcements despite semi-cyclic loads, especially when considering multiple activations throughout a structure's lifecycle. Therefore, this research provides valuable insights into enhancing the durability and safety of existing reinforced concrete structures by using Fe-SMAs.
