12 Sep Experimental work to evaluate time-dependent behavior of NSM CFRP-strengthened RC beams
We are glad to share our new paper entitled “Time-dependent behavior of NSM CFRP-strengthened RC beams under different service temperatures” published by Younes Jahani (PhD student), Marta Baena, Alba Codina (PhD student), Cristina Barris and Lluís Torres at the journal Composites Structures, Volume 300, 116106. This Open Access paper is available online from August 2022.
The use of fiber reinforced polymer (FRP) for flexural strengthening of reinforced concrete (RC) beams has become a popular strengthening technique. Significant amount of work is available on the short-term flexural behavior of RC beams strengthened with near-surface mounted (NSM) technique. However, their time-dependent flexural behavior, specifically under high service temperature, has not yet been addressed. This paper presents an experimental work to evaluate the time-dependent behavior of NSM carbon FRP (CFRP)-strengthened RC beams. The experimental program included 23 beams, where the effect of different parameters such as strengthening (CFRP) area, steel reinforcement ratio and applied temperature (20 and 50 ◦C) have been considered. Experimental results show that the effect of strengthening area is significant on the flexural short-term response of the beams, while minor effects are found on the time-dependent deflections. On the other hand, increasing the service temperature has no significant effect on the short-term tests, but it produces a large increase in the time-dependent deflection of the specimens. Finally, an analytical procedure for the prediction of time-dependent deflections, which is based on the age-adjusted effective modulus method (AEMM), is presented. Good agreement between the experimental results and analytical predictions on time-dependent deflections is shown.
This research was supported by the Spanish Ministry of Science and Innovation (MCIN/ AEI) under project PID2020-119015GB-C22 and the Generalitat de Catalunya (under the grant numbers: 2019FI_B 00054 and 2020_FISDU 00476). The authors also wish to acknowledge the support of S&P Clever Reinforcement Ibérica Lda. for supplying the epoxy resin and the CFRP laminate used in this study.