Abstract:Taking the Xindian Bridge in Ningbo as the background, this paper analyzed the mechanical properties of the integral jacking basket arch bridge during construction. Midas finite element software was used to establish the spatial model of the main bridge, and the deviation of the suspender force and support reaction force of the completed bridge from the design was 1.84% and 1.8%, respectively. The maximum deviation of the displacement calculation of the tie beam at the bridge completion stage was 22 mm, and the maximum deviation of the displacement of the arch rib at the same stage was ?12 mm, which showed that the finite element model simulation method was correct and reliable. During the jacking process, the maximum shear stress of the tie beam calculated based on the truss unit was 112 MPa, which was less than the design strength value of 160 MPa in the specification. According to the calculation method of bearing stiffeners at the support in the specification, the checking result of the local bearing strength of the tie beam was 114 MPa, less than the 355 MPa required in the Specifications for Design of Highway Steel Bridge (JTG D64?2015). The local instability result was 234 MPa, less than 275 MPa required in the specification. According to the analysis of the local model, the equivalent stress of the web calculated by the fourth strength theory was 181.7 MPa, and that calculated by the third strength theory was 204.4 MPa. The results met the requirements of the allowable stress of 252 MPa in the specification. Due to the large force on the web and the insufficient surplus, the shear stress was reduced from 112 MPa to 95 MPa when the forced displacement value of the fulcrum was 2 cm, and no failure and yield of the plate appeared in the whole process of the bridge jacking, which showed that the calculation method and results could guide the actual construction. Two working conditions were calculated for system conversion: ① Symmetrical removal from the center to the edge; ② symmetrical removal from the edge to the center. The analysis results show that the two schemes have little influence on the structural force, but the scheme featuring symmetrical removal from the center to the edge has relatively little deformation of the beam arch, which is beneficial to the installation of the suspender.