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Fatigue performance degradation of steel-FRP composite bar reinforced seawater sea-sand concrete beams: coupled effects of seawater immersion and sustained load

Fatigue performance degradation of steel-FRP composite bar reinforced seawater sea-sand concrete beams: coupled effects of seawater immersion and sustained load
Fatigue performance degradation of steel-FRP composite bar reinforced seawater sea-sand concrete beams: coupled effects of seawater immersion and sustained load

This study aims to explore the coupled effects of environmental and loading conditions on the fatigue degradation of steel-FRP composite bar (SFCB) reinforced seawater sea-sand concrete (SWSSC) beams. Here, the failure modes, surface conditions of SFCBs, fatigue lives, load-deflection curves, crack propagation, and maximum crack width were investigated. The degradation mechanism of fatigue performance of specimens was further revealed. Experimental results indicate that the fatigue lives of unconditioned beams dropped from over 2,000,000 to 124,851 cycles as the stress level increased from 0.2 to 0.4. After 6 months of exposure, the fatigue life of the beam under the single effect of sustained load was over 2 million cycles at a stress level of 0.2, whereas the ultimate capacity after 2 million cycles decreased by 45.2 %. The coupled actions of high-temperature seawater immersion and sustained load degraded fatigue properties in the first 3 months, but the deflection and crack width reduced due to the enhanced flexural stiffness after 6 months. Compared to the sustained load, the high-temperature seawater dominates the coupled effects. Surface conditions and microscale observation of SFCBs indicate that the weakening in fiber-resin interface and the corrosion of steel core lead to the fatigue degradation of beams.

Fatigue degradation, High-temperature seawater environment, Seawater sea-sand concrete beam, Steel-FRP composite bar, Sustained load
Que, Zichao
c1f34f6d-4f51-4fb1-b390-2e04857caadc
Zou, Dujian
f932d3d9-b218-4268-a86e-0bb63aec1e31
Zhang, Ruibo
1b2f60b8-0ff2-445e-8c4b-99afa245d662
Zhou, Ao
5b42c2a4-26b2-416e-ab3c-446f1ece7a20
Li, Ye
86d13351-982d-46c3-9347-22794f647f86
Liu, Tiejun
07e72a65-be75-4b13-b54d-9ed949c93470
Que, Zichao
c1f34f6d-4f51-4fb1-b390-2e04857caadc
Zou, Dujian
f932d3d9-b218-4268-a86e-0bb63aec1e31
Zhang, Ruibo
1b2f60b8-0ff2-445e-8c4b-99afa245d662
Zhou, Ao
5b42c2a4-26b2-416e-ab3c-446f1ece7a20
Li, Ye
86d13351-982d-46c3-9347-22794f647f86
Liu, Tiejun
07e72a65-be75-4b13-b54d-9ed949c93470

Que, Zichao, Zou, Dujian, Zhang, Ruibo, Zhou, Ao, Li, Ye and Liu, Tiejun (2025) Fatigue performance degradation of steel-FRP composite bar reinforced seawater sea-sand concrete beams: coupled effects of seawater immersion and sustained load. Journal of Building Engineering, 105, [112534]. (doi:10.1016/j.jobe.2025.112534).

Record type: Article

Abstract

This study aims to explore the coupled effects of environmental and loading conditions on the fatigue degradation of steel-FRP composite bar (SFCB) reinforced seawater sea-sand concrete (SWSSC) beams. Here, the failure modes, surface conditions of SFCBs, fatigue lives, load-deflection curves, crack propagation, and maximum crack width were investigated. The degradation mechanism of fatigue performance of specimens was further revealed. Experimental results indicate that the fatigue lives of unconditioned beams dropped from over 2,000,000 to 124,851 cycles as the stress level increased from 0.2 to 0.4. After 6 months of exposure, the fatigue life of the beam under the single effect of sustained load was over 2 million cycles at a stress level of 0.2, whereas the ultimate capacity after 2 million cycles decreased by 45.2 %. The coupled actions of high-temperature seawater immersion and sustained load degraded fatigue properties in the first 3 months, but the deflection and crack width reduced due to the enhanced flexural stiffness after 6 months. Compared to the sustained load, the high-temperature seawater dominates the coupled effects. Surface conditions and microscale observation of SFCBs indicate that the weakening in fiber-resin interface and the corrosion of steel core lead to the fatigue degradation of beams.

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More information

Accepted/In Press date: 1 April 2025
e-pub ahead of print date: 2 April 2025
Published date: 1 July 2025
Additional Information: Publisher Copyright: © Elsevier Ltd
Keywords: Fatigue degradation, High-temperature seawater environment, Seawater sea-sand concrete beam, Steel-FRP composite bar, Sustained load

Identifiers

Local EPrints ID: 503637
URI: http://eprints.soton.ac.uk/id/eprint/503637
PURE UUID: 58f55275-5fe3-4e9f-9ff7-240f55a93370

Catalogue record

Date deposited: 07 Aug 2025 16:49
Last modified: 08 Aug 2025 02:14

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Contributors

Author: Zichao Que
Author: Dujian Zou
Author: Ruibo Zhang
Author: Ao Zhou
Author: Ye Li ORCID iD
Author: Tiejun Liu

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