Design of the Upper Steel Structure and Ultimate Bearing Capacity Analysis of Intersecting Joints of the Emei Nanshan Bridge

The distinctive feature of the upper steel structure project of the Emei Nanshan Bridge is that the curved steel columns on both sides of the bridge are skewed. Two single-layer diagonal lattice shells are formed along the bridge’s axis， and the two are connected through trusses and steel beams， forming a unique space steel structure in the direction perpendicular to the bridge’s axis. On this basis， the hyperbolic roof shape was designed through two single-layer lattice shells and two "catenary beams" to meet the design requirements of the scheme. For the lower "X" shaped curved column， ABAQUS CAE was used to conduct an overall stability analysis， and it was concluded that the structure met the overall stability requirements； MIDAS Gen was then used to conduct component section design using the direct analysis method. For the roof "catenary beam" structure， a strength stress analysis under positive wind pressures and a stability analysis under negative wind pressures were conducted， and it was concluded that the "catenary beam" met the structural design requirements. For the intersecting joints of square steel pipes， ABAQUS CAE software was used to analyze the ultimate bearing capacity of the intersecting joints， and the existing test results were used to verify the finite element analysis method. The ultimate bearing capacity of the joints was 2.2 times the design value of the most unfavorable load， which met the design requirements.