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Title: Stress-Strain Relationship for Polyurea-Confined Circular Concrete Columns under Static Loads

Author(s): Ishtiaque Tuhin and Mostafa Tazarv

Publication: Materials Journal

Volume: 117

Issue: 4

Appears on pages(s): 81-94

Keywords: bridge column; confined concrete; confinement; ductility; polyurea; stress-strain relationship

DOI: 10.14359/51724617

Date: 7/1/2020

Abstract:
Confinement enhances mechanical properties of concrete, especially the strain capacity. As a result, confined reinforced concrete (RC) members usually exhibit higher displacement capacities compared to unconfined members. Even though the behavior of concrete confined with external jackets has been extensively investigated in the past, confined properties of polyureajacketed concrete are largely unknown and were investigated in the present study. Thirty concrete cylinders were tested under slow uniaxial compression to investigate mechanical properties of polyurea-confined concrete and to establish stress-strain behavior. It was found that polyurea does not increase the strength of the confined sections under static loads. However, the compressive strain capacity of polyurea-confined concrete is more than 10%, equal to or higher than the reinforcing steel bar tensile strain capacity. Two uniaxial stress-strain models were developed for polyurea-confined concrete with circular sections under static loads. Analytical studies showed that the displacement ductility capacity of low-ductile bridge columns can be doubled using polyurea jackets. This unique property may make this type of confinement a viable retrofit or rehabilitation method to increase the displacement capacity of low-ductile members and structures in seismic regions.