Model Test Study on Long-Span Railway Concrete Arch Bridge with Rigid Skeleton

The Beipanjiang bridge is a 445 m concrete arch reinforced rigid skeleton bridge on the high-speed railway from Shanghai to Kunming. The bridge deck is designed to comply with design rail speeds of 350 km/h and subsequently requires strictly controlled stresses and deformation for this ballast-less track. To verify the safety of the bridge during construction and in service and to rationalise the use of outsourced concrete construction methods, a 1:7.5 scaled model based on the prototype bridge was constructed. The loading method and arrangement of control sections and measuring points are discussed. Comparing the test results and computed results provides a comprehensive understanding of the mechanical behavior of the bridge. The results indicate that the maximum stress of the steel tube is 250 MPa, located at the upper chord of 1/2 cross section and the maximum stress of the C60 outsourced concrete is 17 MPa, located at the side-box bottom of the half cross section, whilst the maximum displacement of the arch ring is 68 mm, also positioned at the half cross section. Considering the stress equivalent and geometric similarity principles, the comparative results indicate that the stress and displacement of the model bridge align with the design parameters of the prototype. Model test results prove that the stress and deformation of the prototype bridge can meet the requirements during construction.