3D laser scanning for predicting the alignment of large-span segmental precast assembled concrete cable-stayed bridges

Reasonable alignment control can simplify the bridge construction process, reduce the complexity and cost of construction, and improve construction efficiency. The prefabricated assembling construction method brings challenges to alignment control. This study proposes a method for predicting the alignment of concrete cable-stayed bridge assemblies in unstressed conditions to accelerate the construction process. The method uses the target paper to identify the 3D coordinates of control points and a coarse-to-accurate alignment method to achieve the virtual preassembly of precast concrete sections. The effectiveness of the method is demonstrated by comparing the errors in key parameters between virtual and physical preassembly and the predicted alignment results obtained through 3D coordinate conversion with the designed precast alignment. The method was applied to the construction of a large-span concrete cable-stayed bridge for a high-speed railroad in Guangdong, China, and the construction period was shortened by about 42 days.