Key Technology and Innovation in Design of Long-Span Railway Prestressed Concrete Cable-Stayed Bridge With Single Cable Plane --Taking the design of the main bridge of Tuojiang Super Bridge on Longchang-Xuyong Railway as an example.

Tuojiang bridge is a controlling project of Longchang-Xuyong Railway. In order to meet the needs of flood discharge, navigation and one span crossing National Nature Reserve, and in combination with the conditions of reserving double lines, the structural form of single cable plane low tower cable-stayed bridge with a main span of 292m is adopted. In order to avoid long-term eccentric load, the phase II dead load of the reserved line is implemented synchronously. By comparing the single box three chamber section, the single box double chamber through anchorage section, the single box single chamber large diaphragm section and the W-shaped section, the W-shaped section with direct force transmission path, reasonable stress and convenient construction is optimized. In view of the complex structure of the continuous inner web when the beam height is changed and it is not convenient for construction, a W-shaped section main beam structure with longitudinal spacing prestressed concrete diagonal bars is proposed on the basis of the traditional W-shaped section. By comparing the two schemes of steel inclined rod and prestressed concrete inclined rod, the characteristics that the prestressed reinforcement in the inclined rod can actively resist the vertical component of the cable, and the preloading stress can effectively avoid large deformation and roof cracking are analyzed. The cantilever pouring construction is adopted for the beam. According to the cable layout and stress needs, combined with the local economic and cultural characteristics of Luzhou, a bridge tower structure with waist tied wine statue shape is proposed. The substructure adopts double thin-wall piers and cast-in-place bored pile foundation. According to the requirements of flood control and navigation and the demand of balanced stress of the two main piers, the bank slope of the main pier is protected. [ABSTRACT FROM AUTHOR]