Effect of prestressing force on flexural behavior of unbonded prestressed concrete beams strengthened by CFRP sheets
Abstract
This paper presents an experimental study on the effect of prestressing force on the flexural behavior of unbonded prestressed concrete (UPC) strengthened by Carbon fiber reinforced polymer (CFRP) sheets. The testing program was carried out on nine large-scale UPC rectangular beams. The investigated parameters included the reduction of prestressing force (0%, 15%, and 30%) and the number of CFRP layers (0, 2, and 4 layers). Experimental results showed that the strengthening effectiveness of CFRP sheets, controlling cracking, and the energy absorption capacity tended to increase with the decrease of prestressing force and decrease with the increase of the CFRP sheets ratio. The effective performance of the CFRP sheets was shown by the increase in the strain of the CFRP sheets which was proportional to the decrease in the prestressing force. The CFRP sheets strongly interacted with tendons, significantly decreased the tendon strain, and delayed the point where nominal yield strain in tendons occurred; this reduction was significant when the prestressing force was small. Besides, the reduction in prestressing force considerably increased the displacement of beams and the additional strain of the tendons (up to 164%), but this increase became smaller as the number of CFRP layers increased.
Downloads
Copyright (c) 2022 Hanoi University of Civil Engineering

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
1. The Author assigns all copyright in and to the article (the Work) to the Journal of Science and Technology in Civil Engineering (JSTCE) – Hanoi University of Civil Engineering (HUCE), including the right to publish, republish, transmit, sell and distribute the Work in whole or in part in electronic and print editions of the Journal, in all media of expression now known or later developed.
2. By this assignment of copyright to the JSTCE, reproduction, posting, transmission, distribution or other use of the Work in whole or in part in any medium by the Author requires a full citation to the Journal, suitable in form and content as follows: title of article, authors’ names, journal title, volume, issue, year, copyright owner as specified in the Journal, DOI number. Links to the final article published on the website of the Journal are encouraged.
3. The Author and the company/employer agree that any and all copies of the final published version of the Work or any part thereof distributed or posted by them in print or electronic format as permitted herein will include the notice of copyright as stipulated in the Journal and a full citation to the Journal as published on the website.