Experimental investigation of actively confined concrete using shape memory alloys

Shin, Moochul; Andrawes, Bassem

doi:10.1016/j.engstruct.2009.11.012

Cited by 154 publications

(67 citation statements)

References 19 publications

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“…The former refers to lateral reinforcement reacting to concrete lateral expansion which causes a confinement pressure under loading due to Poisson's effect and micro-cracking (Shin and Andrawes, 2010). In active confinement the confining pressure applied to prestress the element laterally prior to loading, exerts a small lateral stress on the concrete with the result being an increase in the load capacity (Shin and Andrawes, 2010).…”

Section: Concrete Confinementmentioning

confidence: 99%

Active confinement of weakened concrete columns

Holmes¹,

Niall²,

O’Shea³

2014

Mater Struct

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Section: Concrete Confinementmentioning

confidence: 99%

Active confinement of weakened concrete columns

Holmes¹,

Niall²,

O’Shea³

2014

Mater Struct

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“…Pre-elongated martensitic SMAs with deformation-restraint induce recovery stress by heating up above transformation temperature but lose some level of stress by cooling (see Figure 1(b)); the remaining stress can be used for post-tensioning or prestressing forces. The recover and residual stress highly depends on the alloy composition, manufacturing process, and strain of pre-elongation (Shin & Andrawes, 2010;Choi et al, 2010b;Saleeb et al, 2015a;Saleeb et al, 2015b).…”

Section: Sma Fibers Without End-hooksmentioning

confidence: 99%

New SMA Short Fibers for Cement Composites Manufactured by Cold Drawing

Choi¹,

Kim²,

Jeon³

et al. 2016

JMSR

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This study suggests new shape memory alloy reinforcing fibers manufactured by cold drawing method. This study prepares NiTi shape memory alloy (SMA) wires with diameter of 1.0 mm. Then, the wires are elongated by cold drawing and, thus, the diameters are reduced to 0.93 or 0.965 mm, respectively. This procedure introduces prestrain into the wires. When elongated SMA wires are heated, the shape memory effect is activated; this process recovers the deformed length as well as the reduced diameter due to Poisson's effect. Cold drawn wires with diameters of 0.93 and 0.965 mm recover diameters of 0.018 and 0.024 mm, respectively, with heating. The bulging of the SMA fiber in the radial direction inside cement composites induces confining pressure around the fiber and increases bond strength. When an SMA fiber is heated at the both ends, the heated parts bulge and the fiber shape looks like a dog-bone. Such a dog-bone shaped fiber can provide a geometrical anchoring action that also increases the bond resistance of the fiber. This study conducts pullout tests of SMA fibers to understand their pullout behavior and assess bond stress. The heated fibers and dog-bone shaped fibers increase pullout force compared to those of as-received and cold-drawn fibers. When dog-bone shaped fibers are heated, they show twice the pullout force of dog-bone shaped fibers without heating because geometric anchoring action as well as additional frictional resistance due to confining pressure are activated.

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“…Due to the constraint provided by the concrete, the spiral is not able to restore its original length; rather a large recovery stress is induced in the spiral causing the confining pressure to be exerted on the concrete. Shin and Andrawes (2010) have explored experimentally the behavior of SMA confined concrete using SME. They also applied this technique in seismic retrofitting of concrete columns (Shin and Andrawes 2011b) and repair of RC bridge piers (Shin and Andrawes 2011a).…”

Section: Sma Concrete Confinementmentioning

confidence: 99%

“…Andrawes and Shin (2008) first introduced the idea of using SMA spirals to provide active confining pressure to concrete columns. Shin and Andrawes (2010, 2011aand 2011b) studied the use of shape memory alloy (SMA) spirals to actively confine concrete through thermal prestressing. Their results illustrated that this new technique holds promise for both new and old structures.…”

Section: Introductionmentioning

confidence: 99%

Finite Element Analysis of Actively Confined Concrete Using Shape Memory Alloys

Chen

Andrawes

2014

ACT

Self Cite

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The novel technique of using Shape Memory Alloy (SMA) transverse reinforcement to confine concrete has proven its success in increasing the strength and ductility of concrete elements significantly. This new technique exploits the thermally activated shape memory feature of SMAs to apply high and permanent confinement pressure on concrete. Despite the experimental work done in this topic over the last few years, the numerical/analytical efforts are still lacking. This paper utilizes the analytical framework of the damaged plasticity model along with the finite element method (FEM) to predict and study the behavior of SMA confined concrete under uniaxial compression load. The flow rule and hardening/softening function adopted in the models are developed based on previous test results. The results prove that the finite element models can successfully capture the behavior of SMA confined concrete.

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Experimental investigation of actively confined concrete using shape memory alloys

Cited by 154 publications

References 19 publications

Active confinement of weakened concrete columns

Active confinement of weakened concrete columns

New SMA Short Fibers for Cement Composites Manufactured by Cold Drawing

Finite Element Analysis of Actively Confined Concrete Using Shape Memory Alloys

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