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Advances in Civil Engineering
Volume 2018, Article ID 4064362, 9 pages
https://doi.org/10.1155/2018/4064362
Research Article

EM-Based Monitoring and Probabilistic Analysis of Prestress Loss of Bonded Tendons in PSC Beams

1School of Civil Engineering, Southeast University, Nanjing 210096, China
2Key Laboratory of Concrete and Prestressed Concrete Structure, Ministry of Education, Southeast University, Nanjing 210096, China

Correspondence should be addressed to Zheheng Chen; nc.ude.ues@5120nehcgnehehz

Received 12 July 2018; Accepted 4 September 2018; Published 23 September 2018

Academic Editor: Luigi Di Sarno

Copyright © 2018 Zheheng Chen and Shanwen Zhang. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The prestress level is a key factor of prestressed concrete (PSC) beams, affecting their long-term serviceability and safety. Existing monitoring methods, however, are not effective in obtaining the force or stress of embedded tendons. This paper investigates the feasibility of elastomagnetic (EM) sensors, which have been used for external tendons, in monitoring the long-term prestress loss of bonded tendons. The influence of ambient temperature, water, eccentricity ratio, plastic duct, and cement grouts on the test results of EM sensors is experimentally examined. Based on the calibrated EM sensors, prestress loss of a group of PSC beams was monitored for one year. In order to further consider the high randomness in material, environment, and construction, probabilistic analysis of prestress loss is conducted. Finally, the variation range of prestress loss with a certain confidence level is obtained and is compared with the monitored data, which provides a basis for the determination of prestress level in the design of PSC beams.