Stress-Strain Model for FRP-Confined Concrete in Eccentrically Loaded Circular Columns
Publication: Journal of Composites for Construction
Volume 23, Issue 3
Abstract
Extensive research has been conducted on FRP (fiber-reinforced polymers)-confined concrete columns under concentric compression, leading to many stress-strain models for such concrete. These concentric-loading (CL) stress-strain models have generally been used in the analysis of both concentrically and eccentrically loaded columns. Existing tests, however, have shown that eccentrically loaded FRP-confined concrete columns exhibit some behavioral aspects that cannot be closely predicted using a CL stress-strain model. This paper presents an in-depth investigation into this problem using an advanced three-dimensional (3D) finite element (FE) approach. The stress-strain response of concrete is shown to vary significantly over the section, and the direct use of a single CL stress-strain model for the entire section in the analysis of eccentrically loaded columns may lead to significant errors in the prediction of ultimate displacement/curvature. A stress-strain model for the confined concrete at the extreme compression fiber of the section is also shown to provide a relatively simple and much more accurate option for predicting the ultimate displacement/curvature of eccentrically loaded columns. Based on this conclusion, a so-called eccentricity-dependent (EccD) stress-strain model is proposed based on a comprehensive parametric study using the FE approach. The proposed model can be directly used in a section analysis or a theoretical column model and is proven to provide much more accurate predictions of the ultimate displacement/curvature of test columns than existing CL stress-strain models.
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Acknowledgments
The authors are grateful for the financial support received from the National Key R&D Program of China (Project No. 2017YFC0703000) and the Research Grants Council of the Hong Kong Special Administrative Region (Project Reference Nos. PolyU 5252/13E and PolyU 152153/14E). In addition, thanks are due to Dr. Tao Jiang of Zhejiang University, China, for the sharing of his test data reported in Jiang et al. (2014).
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Published In
Journal of Composites for Construction
Volume 23 • Issue 3 • June 2019
Copyright
©2019 American Society of Civil Engineers.
History
Received: Oct 12, 2017
Accepted: Nov 29, 2018
Published online: Apr 1, 2019
Published in print: Jun 1, 2019
Discussion open until: Sep 1, 2019
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