Assessing Immediate and Time-Dependent Instantaneous Stiffness of Cracked Reinforced Concrete Beams Using Residual Cracks
Publication: Journal of Structural Engineering
Volume 144, Issue 4
Abstract
Under normal in-service conditions, beams and slabs in reinforced concrete structures are usually cracked. Concrete cracking and steel-concrete bond damage lead to an irreversible reduction in the overall stiffness, thereby affecting the serviceability of reinforced concrete structures. The method proposed in this paper aims to assess both the steel-concrete bond damage and the bending stiffness of existing structures based on the cracking pattern observed in situ including the location of bending cracks, their spacing, and their width. The time-dependent effects of creep and shrinkage are also considered. Short-term and long-term experimental results obtained from tests on five reinforced concrete beams are used to evaluate the effectiveness of the method. For each beam, the cracking pattern and the width of cracks measured immediately after first loading and after a 6-month period of sustained loading are used to assess the immediate and time-dependent instantaneous stiffness of the beams. The stiffness and the load-deflection response determined using the proposed method are shown to agree well with experimental observations.
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Acknowledgments
The authors are very grateful for the funding from National Key Research and Development Program of China with Grant Nos. 2016YFC0802205 and 2016YFB1200401, Projects 51778535 and 51778537 supported by National Natural Science Foundation of China, Projects DP110103028 and DP140100529 supported by the Australian Research Council, and Research and Development Project 2014-02-015 supported by Department of Communications of Guangdong Province. The first author wishes to thank the Key Laboratory of High-speed Railway Engineering, Ministry of Education, Southwest Jiaotong University, People’s Republic of China, for its support.
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Published In
Journal of Structural Engineering
Volume 144 • Issue 4 • April 2018
Copyright
©2018 American Society of Civil Engineers.
History
Received: Nov 25, 2016
Accepted: Oct 18, 2017
Published online: Feb 10, 2018
Published in print: Apr 1, 2018
Discussion open until: Jul 10, 2018
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