Large Span Double Track Railway Steel Truss Girder Cable-stayed Bridge By Force Characteristics

Hanjiat Yangtze River Railway Bridge is a double tower, five-span continuous steel truss cable-stayed bridge with span arrangement (81+135+432+135+82) m. The bridge allows two lines railway. Orthotropic monolithic steel deck is adopted, which works together with the main truss. So far, cable-stayed bridges have seldom been applied in railway bridges. There is no railway cable-stayed bridge with span as long as Hanjiat Yangtze River Railway Bridge at home and abroad. The mechanical behavior of the bridge was studied in this paper. Main work of this paper is as follows:1.Space finite element model of the full bridge was established adopting SPB(Space Plate-Beam)method. The mechanical characteristics of the bridge under dead load, worst-case of living load and additional forces were studied. The results show that the working condition of the bridge is reasonable and the stiffness and strength meet the requirements.2.The effects of the break joints in concrete slab were studied. The results show that the break joints of the concrete slab above cross beams at chord joints, can effectively decrease the peak tensile stress of the concrete slab nearby the break joints, but they have no effect on the stress of the concrete slab 0.5m away from the break joints and the steel structure.3.The reasonably pouring sequence for the concrete slab was studied. The results show that, the pouring sequence of concrete slab mainly affects the self-weight stress of the concrete slab. The tensile stress of the middle midspan area is largest. Therefore, the reasonably pouring sequence is to pour the concret slab in this area at last, so that the self-weight of the concrete slab would not creat tensile stress in this area.4. The effects of the concrete slab on the bridge stiffness and mechanical behavior were studied. The results show that, the concrete slab can increase the vertical stiffness and the lateral stiffness of the bridge by 1.8% and 7.5% respectively, effectively decrease the stress of the steel decks, but little change the stress of of the main trusses.With the thickness and width of the concrete slab increased, the lateral stiffness of the bridge increased and the stress of the steel decks increased, while the vertical stiffness and the stress of the main trusses changed little.The research results in this paper not only service design of Hanjiat Yangtze River Railway Bridge but also provide references for other similar structures.