Title:
FRP Jacketed and Shape-Modified Compression Members: II – Model
Author(s):
Chris Pantelides and Zihan Yan
Publication:
Structural Journal
Volume:
103
Issue:
6
Appears on pages(s):
226-235
Keywords:
column; confined concrete; post-tensioning; stress-strain
DOI:
10.14359/18245
Date:
11/1/2006
Abstract:
Rehabilitation of concrete columns using fiber-reinforced polymer (FRP) composites is effective for improving strength and displacement ductility. The stress-strain curve of confined concrete is necessary for developing the moment-curvature relationship of reinforced concrete compression members for seismic rehabilitation design. Although a few models exist for square and rectangular columns, most FRP-confinement models are for circular columns. A confinement model for different types of FRP-confined concrete, including bonded FRP composite jackets for square and rectangular sections, and shape-modified circular and elliptical sections confined with post-tensioned FRP shells is presented. The model is based on a plasticity theory using the Willam-Warnke five-parameter concrete model and the Pantazopoulou-Mills theory of degradation of concrete elastic modulus. The Popovics concrete model for hardening behavior and the Saenz model for softening behavior are applied in the formulation. The confinement model is implemented by an incremental approach which accounts for the variable FRP confinement and dilation behavior as axial stress is increased. The model is verified using medium- and large-scale tests of FRP-confined concrete compression members with bonded FRP jackets or post-tensioned FRP shells.