Virtual pre-assembly method for bridge tower crossbeam lifting based on temperature effect analysis and 3D laser scanning technology

By transferring on-site construction operations to a controlled factory environment, prefabricated construction technology has significantly reduced the adverse interference of factors such as transportation and weather conditions on the construction process. However, factors including fabrication and assembly inaccuracies, along with the deformation of components, have the potential to reduce the precision of prefabricated assembly. To address these challenges, this study proposes a virtual pre-assembly method for bridge tower crossbeam lifting, integrating temperature effect analysis with 3D laser scanning technology. The method begins with a theoretical investigation into the deformation behavior of bridge towers and crossbeams under different temperature gradient patterns. Radiative heat transfer theory is then employed to compute the thermal profile of a bridge tower, which is introduced into a finite element model to analyze and validate the time-dependent displacement characteristics of the structure. High-precision point cloud data of crossbeam connection interfaces are acquired via 3D laser scanning. These data are aligned using point cloud registration techniques to achieve accurate spatial integration of the crossbeam and bridge tower. By incorporating the time-varying displacement data obtained from thermal analysis, the spatial positions of key control points in the point cloud are adjusted to simulate deformations encountered during actual construction. This virtual pre-assembly approach provides a visual and quantitative assessment of alignment tolerances with daily periods, enabling more accurate monitoring and control of the crossbeam lifting process.