Rational selection of cross section of steel truss girder for New Baishatuo Changjiang River six-line railway bridge

The main bridge of the New Baishatuo Changjiang River Bridge is a five-span continuous steel truss girder cable-stayed bridge with span arrangement (81+162+432+162+81) m. The upper deck of the bridge is designed to carry four-line passenger dedicated railways while the lower deck to carry two-line freight railways and the bridge is the first railway bridge to carry six-line railways in China. To rationally select the cross section of the steel truss girder for the bridge in the design, the schemes of the cross sections of the 2 main trusses or 3 main trusses of trapezoid inclined trusses or rectangular vertical trusses were compared and analyzed from aspects of the structural spatial composition, force conditions and economy rationality. The results of the comparison and analysis suggest that the scheme of the 2 main trusses of rectangular vertical trusses for the steel truss girder of the bridge can not only meet the requirements of the railway line arrangement, but also has the advantages of the rational structural force conditions, convenient steel structure manufacturing and installation and better economy. In such case, the scheme of the 2 main trusses of rectangular vertical trusses is finally chosen for the bridge. The steel truss girder of the chosen scheme is 24.5 m wide and 15.2 m high. On the upper deck of the truss girder is the structure of integral orthotropic plate and on the lower deck is structure of cross beams, stringers and ballast channel slabs. ©, 2014, Bridge Construction. All right reserved.