Influence of shape memory alloy on seismic behaviour of hollow-section concrete columns

Abstract

The influence of shape memory alloy (SMA) reinforcement on the non-linear static and dynamic responses of hollow-section concrete columns to earthquakes was investigated. The seismic performance of concrete columns reinforced with steel and with a mix of SMA and steel was compared by assessing their ductility ratios, dissipated energies, strain recovery capacities and collapse drifts. The influence of near- and far-field ground motions on the static and dynamic responses of the test columns was also investigated. To verify the results, the columns were subjected to a near-field ground motion related to an existing earthquake and the relative displacement response history was compared with experimental results. Compared with the steel-reinforced column, it was found that the use of the hybrid SMA–steel reinforcement was more effective at recovering strains and reduced the residual deflections. On the other hand, the steel-reinforced column had a greater ductility ratio and energy dissipation capacity. It is therefore important to find an optimal combination length for the two types of reinforcement in a concrete column. The results indicated that the optimum reinforcement configuration involves replacing steel with SMA at 15–20% of column height, which includes the probable plastic hinge length.

Seismic Behavior and Modeling of Ductile Composite Steel-Trussed Concrete Beam to Column Joints

“…The first modeling approach considers a lumped plasticity model [20][21][22]. In the case of the hinged base column (specimen 1), the model is composed of two elastic elements connected by a plastic hinge inserted at the end of the beam (Figure 11a).…”

“…In order to easily equip with efficient and cost-effective seismic damage-proof connections of RC moment-resisting framed structures endowed with semi-prefabricated steel-trussed concrete beams and standard RC pillars cast-in-place, a recent study has developed specific energy dissipating systems for hybrid beam-to-column connections using both experimental, numerical, and analytical methods [15][16][17][18]. Generally, the use of friction dampers prevents damage to the structural elements, improves the expected performance, and limits damage to the panel zone [19], while the use of devices based on shape memory alloys (SMA) is more effective at recovering strains and reducing residual deflections [20].…”

Experimental Study on the Impact of Using FRP Sheets on the Axial Compressive Performance of Short-Circular Composite Columns

“…The most typical method is the augmentation method of wrapping FRP layers [11][12][13] and using shape memory alloy (SMA) [14,15]. These reinforcement techniques all make use of the superior mechanical properties of external materials, such as the light weight and high strength of FRP materials [16][17][18][19][20], as well as the high ductility and good energy dissipation capacity of SMA [15].…”