Title:
Nonlinear Moment-Curvature Response and Ductility of Hybrid Reinforced Concrete Columns
Author(s):
Sherif Osman
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/29/2020
Abstract:
Harsh winter is an important factor behind the deterioration of concrete infrastructure because of using deicing salt. To mitigate this issue, a hybrid reinforcement configuration for reinforced concrete (RC) sections utilizing Glass Fiber Reinforced Polymer (GFRP) or Carbon Fiber Reinforced Polymer (CFRP) rebar along with conventional steel rebar has been proposed where steel rebar in the inner cage can provide good ductility against sudden FRP rebar rupture and FRP being in the outer cage can provide the required corrosion resistance. Currently, little research has been directed towards identifying the nonlinear attributes of hybrid RC columns. Here, the moment-curvature (MC) analysis is conducted for such hybrid RC sections under combined flexure and axial load. The MC relationship is an effective representation of the initial and effective stiffness, ductility and other nonlinear characteristics of a section. In this study, the experimental and numerical MC analysis of several hybrid RC sections are presented. S-CALC software (by S-FRAME Software Inc.) is used to determine the MC response of hybrid RC sections, which is first validated with the experimental results. In a parametric study, the softening characteristics and post-yield behavior of concrete are presented using various material models for confined and unconfined concrete. Similarly, yielding, strain hardening, and/or rapture states of different reinforcement material (Steel, GFRP and CFRP) are demonstrated. The effects of various simplifying assumptions that are usually applied to the stress-strain relationship of steel and concrete on the MC response are discussed.