English：

The Anjiazhuang Bridge of the National Highway 109 New Line Expressway is located in themountainous valley of the Fengsha Railway Bridge. The construction environment is harsh and theconstruction technology is extremely difficult. The transverse asymmetric eccentricity of the curved steeltruss cable⁃stayed bridge is significant. During the assembly process, it is easy to be offset by thehorizontal force, and the center of gravity of the beam is continuously and dynamically converted, whichbrings great technical challenges and construction risks to the bridge system conversion and the stabilitycontrol of the pier top rotation. By setting up a cantilever temporary pier and a pier top rotation system atthe pier top node, the rotation stability is improved by relying on the three⁃point support technology oflarge eccentric counterweight. At the same time, BIM technology is integrated to carry out parametermodeling verification, working condition simulation and deduction, optimize the installation process flow,and strengthen the construction process monitoring. Finally, the high⁃altitude pier top system conversionand rotation construction of double⁃curved steel truss girder cable⁃stayed bridge are successfully realized.