Modeling of passive and active external confinement of RC columns with elastic material

Abstract

One of the most attractive applications of composite materials is their use as confining devices for concrete columns, which may result in remarkable increases of strength and ductility. The current investigation focuses on the modeling of reinforced concrete columns passively or actively confined by composites, under axial load. Furthermore, the research highlights the effectiveness and modeling of ultra high extension capacity fiber ropes implemented as external confining reinforcement so as to upgrade ductility and strength of concrete columns. It concerns columns of square cross-section with plain or steel reinforced concrete. The novel confining technique uses composite rope made of polypropylene fibers as passive or pretensioned reinforcement while it presents linear elastic behavior up to failure and is applied by hand. It may enable confined columns to dissipate enormous amounts of earthquake induced energy through concrete deformation. The proposed constitutive model is compared against available experimental results involving circular or square columns with passive or active FRP confinement.

Numerical Study on Seismic Behavior of Underwater Bridge Columns Strengthened with Prestressed Precast Concrete Panels and Fiber-Reinforced Polymer Reinforcements

“…For concrete core 1 and concrete core 2, the ultimate strengths and strains would be enhanced by the single or dual confinements provided by the FRP spiral stirrup and steel spiral stirrup. However, due to a lack of experimental studies, a series of existing FRP-confined concrete models [21][22][23] were adopted to calculate the ultimate strengths and strains for the concrete materials. For concrete core 1, the ultimate strength and strain were calculated by using the FRP sheet confined concrete model proposed by Wu et al [21]; the ultimate strength was taken as 1.8 times of its compressive strength, and the ultimate strain equals to −0.02.…”

“…For concrete core 1, the ultimate strength and strain were calculated by using the FRP sheet confined concrete model proposed by Wu et al [21]; the ultimate strength was taken as 1.8 times of its compressive strength, and the ultimate strain equals to −0.02. For concrete core 2, the ultimate strength and strain were expected to be larger than those of concrete core 1 due to an extra confinement provided by the steel spiral stirrup [22]. However, due to the potential negative effects such as stress lagging of the FRP spiral stirrup or a weak old-new concrete interface, which could possibly lower the ultimate strength, a conservative ultimate strength, which equals to 2 times of the compressive strength [23], was taken for concrete core 2, and the corresponding crushing strain remains the same with that of concrete core 1.…”

Retraction: Moment–curvature response of engineered cementitious composites under cyclic loading

“…Rousakis and Tourtouras investigated the applicability of constitutive model based on simple mechanics for the prediction of the stress-strain behavior of reinforced or plain concrete columns confined by composites under axial load. 33 In present research, the following analytical steps are considered.…”

Hollow-Core FRP–Concrete–Steel Bridge Columns under Torsional Loading

“…The shear strain on the steel tube at the surface level of the footing was 800μ, which was far below the shear yield strain of the steel tube, which was 2800μ. It is worth noting that the strain redistribution was not noticed in the steel tube, unlike in the case of axial loading when the GFRP was used [32][33][34][35]. The reason was that the column relied mainly on the steel tube resistance under torsion loading, and the effect of the GFRP tube was negligible.…”