Abstract:Research purposes: Maglev trains have extremely high requirements on the rigidity and strength of the box girder, but there is no relevant test on the crack resistance of the maglev box girder. In order to evaluate the mechanical performance of the medium and low speed maglev box girder, this paper carried out a bending crack resistance static load test on the Changsha 25 m maglev standard box girder. By testing the displacement, stress and crack development of the standard box girder under load, the strength, stiffness and crack resistance of precast beams were evaluated in actual working conditions, to provide test basis for the normal operation of maglev trains, and provide data support for similar projects. Research conclusions: (1) The girder is in the elastic state before the cracking, and the stiffness can meet the design requirements. (2) The measured cracking load is 258.9 kN, which is higher than the theoretical value. It can be evaluated as the crack resistance of the full prestressed girder. (3) The strain distribution of the cross section of the girder before the crack is basically conformed to the assumption of the flat section, and the difference between the measured neutral axis and the theoretical value is very small. (4) The cross-section strain of box girder is obviously redistributed after cracking. With the increasing of the load, the width of cracks in the mid span increases. When loading up to 372.2 kN, the maximum crack width of the box girder is 0.053 mm. (5) The research in this paper shows that the mechanical performance of the 25 m maglev standard box girder meets the requirements of the specification, and its structure and design can be popularized and applied in medium and low speed maglev projects.
赵志军. 中低速磁浮标准箱梁弯曲抗裂试验及性能评价[J]. 铁道工程学报, 2022, 39(2): 73-78.
ZHAO Zhijun. Bending Test and Performance Evaluation of Medium and Low Speed Maglev Standard Box Girder. Journal of Railway Engineering Society, 2022, 39(2): 73-78.
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