Strain gradient effects on flexural strength design of normal-strength concrete columns

Ho, J.C.M. and Peng, J. (2011) Strain gradient effects on flexural strength design of normal-strength concrete columns. Engineering Structures, 33 1: 18-31. doi:10.1016/j.engstruct.2010.09.014

Author Ho, J.C.M.
Peng, J.
Title Strain gradient effects on flexural strength design of normal-strength concrete columns
Journal name Engineering Structures   Check publisher's open access policy
ISSN 0141-0296
Publication date 2011
Year available 2011
Sub-type Article (original research)
DOI 10.1016/j.engstruct.2010.09.014
Open Access Status
Volume 33
Issue 1
Start page 18
End page 31
Total pages 14
Place of publication Kidlington, Oxford, United Kingdom
Publisher Pergamon Press
Collection year 2011
Language eng
Abstract The equivalent rectangular concrete stress block has commonly been adopted for the flexural strength design of reinforced concrete (RC) members for decades. In this stress block, the equivalent concrete stress is expressed as αfc' (fc' is the uni-axial concrete cylinder strength). Currently, the value of α adopted in various RC design codes is only concrete-strength dependent and equal to 0.85 for NSC. However, in an experimental study conducted previously by the authors on NSC columns subjected to concentric and eccentric axial loads, it was found that α increases significantly as the strain gradient increases. Therefore, the effect of the strain gradient should not be neglected. In this paper, a review on the previous test results on NSC columns is presented and a strain-gradient dependent equivalent rectangular concrete stress block is developed. Based on this proposed stress block, a new flexural strength design method for NSC columns that incorporates the effects of the strain gradient is proposed. A series of column interaction diagrams with various concrete strengths and steel ratios are derived for design purposes. Lastly, these interaction diagrams are compared with the existing column design charts provided in various RC design codes to verify their applicability.
Keyword Columns
Concrete stress block
Flexural strength
Normal-strength concrete
Reinforced concrete
Strain gradient
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: School of Civil Engineering Publications
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Created: Thu, 23 Oct 2014, 17:49:24 EST by Johnny Ho on behalf of School of Civil Engineering