Abstract
In this paper, the whole life cycle (failure-reinforcement-failure) durability and related fatigue properties of prestressed hollow beam under carbonation erosion environment were studied. According to a 20 m hollow slab beam, the model of prestressed hollow beam was designed and made, and the durability and fatigue tests for the whole life cycle of prestressed hollow beam were carried out. The results showed that the compressive strength and elastic modulus of the specimens increased by about 20% under the action of carbonization erosion. With the increase of fatigue loading cycles, the crack occurrence and development speed of carbonized erosion components were greater than those of healthy components, and the fatigue life decreased sharply from 3 million cycles to 50,000 cycles. Pasting carbon fiber and steel plate had better reinforcement effect on the damaged prestressed plate beam and could help improving the fatigue life of the reinforced component. Comparing the reinforcement of different strengthening methods, it is found that the steel-plate-reinforced components have better mechanical properties and antifatigue attenuation characteristics than the carbon-fiber-reinforced ones. The research results have important theoretical value for improving the durability of structure and prolonging its service life.
Highlights
With the continuous worsening of environmental problems, the effects of adverse environmental factors such as chloride ion penetration, carbonization, and freeze-thaw cycles on bridge structure have become increasingly severe, resulting in widespread early damage of the in-service bridge
It displays that the impact resistance performance of the test plate after environmental erosion is significantly weaker than that of the uneroded reinforcement member under the fatigue load, and the impact resistance of the test plate strengthened by the bonded steel plate is better than that of the test plate reinforced with the carbon fiber cloth
E increase in the deflection and strain of the bonded steel plate is better than that which reinforced by carbon fiber cloth. e experimental results show that both reinforcement methods have good reinforcement effects
Summary
With the continuous worsening of environmental problems, the effects of adverse environmental factors such as chloride ion penetration, carbonization, and freeze-thaw cycles on bridge structure have become increasingly severe, resulting in widespread early damage of the in-service bridge. The relevant scholars at home and abroad have conducted research on the fatigue performance of reinforced concrete structures strengthened using the method of pasting a steel plate and carbon fiber cloth. As compared with the unreinforced beams, the deflection and crack width of the strengthened test beams were reduced, and the static load ultimate bearing capacity of the test beams was significantly improved Both the carbon fiber board and the bonded steel sheet could improve the fatigue performance of the reinforced concrete structure. E research results have important theoretical and engineering significance for revealing the mechanical properties of concrete materials under carbonization erosion, clarifying the entire life cycle durability decline mechanism of bridge structures under carbonization and its relationship with the fatigue characteristics, and optimizing bridge structure reinforcement schemes Erefore, based on the principle of similarity and in combination with the actual bridge structural parameters, 2 m long prestressed hollow slab beam model was designed and fabricated. e carbonized erosion tests were performed in the modified rapid carbonization tank to study the influence of carbonization erosion on the fatigue characteristics of a prestressed hollow slab and reinforced prestressed hollow slab beam. e durability index and structural fatigue characteristics of prestressed slab beam under carbonization erosion were established. e research results have important theoretical and engineering significance for revealing the mechanical properties of concrete materials under carbonization erosion, clarifying the entire life cycle durability decline mechanism of bridge structures under carbonization and its relationship with the fatigue characteristics, and optimizing bridge structure reinforcement schemes
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