Comparing the cyclic behavior of concrete cylinders confined by shape memory alloy wire or steel jackets

Abstract

Shape memory alloy (SMA) wire jackets for concrete are distinct from conventional jackets of steel or fiber reinforced polymer (FRP) since they provide active confinement which can be easily achieved due to the shape memory effect of SMAs. This study uses NiTiNb SMA wires of 1.0 mm diameter to confine concrete cylinders with the dimensions of 300 mm × 150 mm (L × D). The NiTiNb SMAs have a relatively wider temperature hysteresis than NiTi SMAs; thus, they are more suitable for the severe temperature-variation environments to which civil structures are exposed. Steel jackets of passive confinement are also prepared in order to compare the cyclic behavior of actively and passively confined concrete cylinders. For this purpose, monotonic and cyclic compressive loading tests are conducted to obtain axial and circumferential strain. Both strains are used to estimate the volumetric strains of concrete cylinders. Plastic strains from cyclic behavior are also estimated. For the cylinders jacketed by NiTiNb SMA wires, the monotonic axial behavior differs from the envelope of cyclic behavior. The plastic strains of the actively confined concrete show a similar trend to those of passive confinement. This study proposed plastic strain models for concrete confined by SMA wire or steel jackets. For the volumetric strain, the active jackets of NiTiNb SMA wires provide more energy dissipation than the passive jacket of steel.

Lateral cyclic behavior of bridge columns confined with pre-stressed shape memory alloy wires

“…Tran, Balandraud, and Destrebecq (2015) compared the failure modes and stress-strain diagrams of active and passive confinements by SMA wires through crush tests. In addition, the uniaxial cyclic stress-strain behavior of concrete cylinders confined by SMA wires was also investigated (Park et al 2011;Chen and Andrawes 2017). The stress deterioration ratio and stress-strain envelopes were tested.…”

Analysis of Bearing Capacity and Seismic Performance of Circular RC Columns Strengthened with Externally Wrapped Steel Plates

“…Due to the constraints of the steel pipes, the overall performance of the strengthened members is better, and the bond between the new and old concrete joint surfaces is stronger. Meanwhile, the lateral deformation capacity of the strengthened columns is also enhanced [34], making the original RC columns in a good three-way stress state [35]. (4) High compressive bearing capacity and good seismic performance [36].…”

Energy-dissipating and self-repairing SMA-ECC composite material system

“…SMAs, such as Nickel-Titanium alloys [14,15] or Copper-Alluminium-Manganese alloys [16][17][18][19], feature shape memory effect and superelasticity. SMAs have been studied as partial replacement of steel rebars [20][21][22][23][24][25][26][27][28][29], the confinement for column [30][31][32][33][34][35][36][37], fibers [38][39][40][41][42], and external devices and dampers [43][44][45][46][47][48][49][50][51] for concrete structures. These studies showed that with particular prestrain, SMA can improve energy dissipation capacity of RC members while reducing residual crack width and deformation.…”