PRESTRESS LOSS OF SELF-COMPACTING CONCRETE BEAMSREINFORCED WITH EXTERNAL CFRP TENDONS

doi:10.19936/j.cnki.2096-8000.20210628.004

Abstract

Abstract: This study aimed to provide a comprehensive experimental, analytical and numerical investigation of prestress loss of self-compacting concrete (SCC) beams with external CFRP tendons. A total of 6 specimens of SCC beams and 2 specimens of controlling beams were designed and tested to get the laws of prestress loss, including anchorage loss, temperature difference loss, relaxation loss, shrinkage loss and creep loss of CFRP bars, at different prestressing and concrete strength levels. The comparison of prestress loss between self-compacting concrete and controlling beams were also made. The results show that the theoretical value of anchorage loss is larger than actual value. The formulas for controlling beams are also suitable for CFRP tendons, while some parameters in the formulas should be determined by tests. Linear expansion coefficient of CFRP bars and SCC calculated by the temperature difference loss formula was about 500% bigger than the actual value. So the formulas for controlling beams are no longer suitable for FRP-SCC components. The total theoretical loss of relaxation of CFRP bars, shrinkage and creep of concrete were about 20% different from the test results, while the theoretical formula exhibited the larger error for the SCC specimens of concrete with the strength level of C65. The loss of external prestress of CFRP bars decreased with the decrease of prestress level, and the maximum reduction of prestress loss is 15.2%. The prestress loss increased with the increase of concrete strength, with the maximum increase of 10.4%. The prestress loss of controlling concrete specimens is greater than that of SCC specimens, and the maximum difference is 11%.

Key words: CFRP tendons; external prestress; prestress loss; anchorage loss; temperature difference loss

CLC Number:

TB332

WU Li-li, GENG Da-lin, YUE Yan-song, YANG Jia-qi. PRESTRESS LOSS OF SELF-COMPACTING CONCRETE BEAMSREINFORCED WITH EXTERNAL CFRP TENDONS[J]. COMPOSITES SCIENCE AND ENGINEERING, 2021, 0(6): 26-33.

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