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Abstract:
To enhance the robustness of the suspended deck system of half-through and through arch bridges, the suspended deck system of half-through and through arch bridges without a stiffening girder in the longitudinal direction of the bridges was taken as the research object, a robustness strengthening structure with a steel tubular truss (STT) stiffened longitudinal girder was proposed for the suspended deck system, and a comparative analysis was made on the dynamic responses of the remained structures at the moment of hanger fracture before and after the robustness strengthening of the suspended deck system. A test and a finite element analysis were conducted on the model of the robustness strengthening structure with an STT stiffened longitudinal girder, and the mechanical performance and failure mode of the strengthened structure after the hanger fracture were studied. The effects of the preload of finish-rolled screw-thread steel bar, the thickness of perforated steel plate, and the material on the mechanical performance of the robustness strengthening structure were discussed. Research results show that after the suspended deck system is strengthened by the STT stiffened longitudinal girder, the maximum vertical displacement and stress of the deck system reduce by 1.30(1.31) and 3.31(1.99) times, respectively, when the long (short) hanger fractures. The maximum cable force of the hanger adjacent to the fractured one reduces by 1.25 (1.25) times. In the elastic-plastic stage, the perforated steel plate of the structure strengthened by the STT stiffened longitudinal girder is subjected to bending deformation, and the embedded steel rebar near the bottom of the cross beam is damaged. When the ultimate load is reached, a crack appears on the weld between the middle-lower stiffened steel plate and the perforated steel plate. Then, a crack appears on the weld between the lower chord and the perforated steel plate, and the carrying capacity is thereby lost. The reasonable preload of the finish-rolled screw-thread steel bar is 50 kN, and the reasonable thickness of the perforated steel plate is 20 mm. The ultimate load of the strengthened structure increases by 11.9% when the material of the perforated steel plate is updated from Q235 to Q345. This indicates that enhancing the material strength of the perforated steel plate can effectively improve the ultimate bearing capacity of the strengthened structure. To sum up, utilizing the STT stiffened longitudinal girder to reinforce the suspended deck system in half-through and through arch bridges can effectively strengthen its robustness. © 2022 Chang'an University. All rights reserved.
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Source :
Journal of Traffic and Transportation Engineering
ISSN: 1671-1637
CN: 61-1369/U
Year: 2022
Issue: 6
Volume: 22
Page: 95-113
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