Cyclic behavior of hybrid RC columns using High-Performance Fiber-Reinforced Concrete and Ni-Ti SMA bars in critical regions

Abstract

[EN] Thanks to their excellent deformation capacity and ductility, smart materials are now being increasingly used in the construction industry, one example being superelastic Shape Memory Alloys (SMA)such as Ni-Ti, which can recover from large strains without generating significant residual strains. The purpose of this work was to study the behavior under cyclic loading of hybrid-reinforced concrete columns containing super-elastic Ni-Ti bars and High-Performance Fiber-Reinforced Concrete (HPFRC) in their critical end regions, where plastic hinges may form (column ends). This critical region is a dissipative zone of the column where the most adverse combination of actions occurs. An experimental study was carried out to simulate inter-story columns in which the effects of the axial level and continuous or discontinuous beam-column joints were analyzed. The specimens with continuous joints were found to display greater lateral strength, ductility and energy dissipation, while those with discontinuous joints underwent smaller residual displacements and less damage in the critical regions of the columns.