Creep Analysis of Axially Loaded Frp Concrete Columns

Abstract

In this investigation, a three-dimensional finite element model has beenused to analyze four concrete-filled fiber reinforced polymer (FRP) tubesand two fiber-wrapped concrete columns under sustained axialcompressive load utilizing ANSYS software. Twenty-node viscoelasticelement has been used to model the concrete, while the FRP tube ismodeled using twenty-node isoparametric solid element and fiber-wrap ismodeled using eight-node isoparametric shell element, both connected byeight-node isoparametric interface element. Also, the effects of someimportant parameters including concrete compressive strength, tube wallthickness, number of fiber-wraps, column diameter, ultimate creepcoefficient, and type of FRP on the creep behavior of these columns havebeen investigated. Comparison between the numerical and availableexperimental long-term results showed good agreement with a maximumdifference of the total strain values of 5.5%, which confirms the accuracyand validity of the models and materials constitutive relations and methodused. The numerical results also showed that a stress transfer in theconcrete-filled FRP column occurred with time between the FRP tube andthe concrete, leading to a 22% stress reduction in the concrete and astress increase in the FRP of 25% after 200 days of loading.