Research on Evaluation Method of Completed Bridge Alignment of Long-span Railway Bridges Based on Riding Quality.

The completed bridge alignment of super long-span railway bridges is prone to large deviation from the design alignment, which leads to the unrealization of the original rail surface design alignment, and it is usually necessary to change the rail surface alignment on the basis of the completed bridge alignment. In order to ensure that the changed rail surface alignment meets the requirements of train operation performance, it is particularly important to reasonably evaluate the completed bridge alignment of long-span railway bridges before laying the track. In this paper, the characteristics of the measured completed bridge alignment of a long-span railway bridge in China are analyzed. Combined with the adjustable capacity of ballast bed on the bridge, an evaluation method of completed bridge alignment of long-span railway bridges based on riding quality is proposed, and the amplitude of completed bridge alignment within the sensitive wavelength range of the vehicle body is taken as the evaluation index. Firstly, according to the evaluation principle that the vertical acceleration of vehicle body caused by line random irregularity, additional deformation of bridge under external loads and rail surface alignment does not exceed level I management standard, the maximum acceleration caused by rail surface alignment within the sensitive wavelength range of vehicle body is determined. Then the correlation between vertical acceleration of vehicle body and chord measurement amplitude, and the correlation between chord measurement amplitude and linear amplitude are studied to determine the maximum amplitude of rail surface alignment within the sensitive wavelength range of vehicle body. Finally, by deducing the correspondence between rail surface alignment amplitude and completed bridge alignment amplitude within the sensitive wavelength range of the vehicle body, the limit value of the evaluation index is formulated. Taking a kilometer-level suspension bridge in China as an example, the limit value of the evaluation index is determined to be 58 mm according to the method of this paper. The maximum value of the measured completed bridge alignment within the sensitive wavelength range of the vehicle body of this bridge is 36 mm, which does not exceed the limit value, indicating that the control effect of the completed bridge alignment is good, and on the premise of meeting the requirements of ballast bed thickness, the rail surface alignment which meets the riding quality can be laid on the basis of the completed bridge alignment. [ABSTRACT FROM AUTHOR]