Automated measurement of cable shape in super-long span suspension bridges

The current measurement of the main cable shape of large-span suspension bridges relies on the total station, which is time-consuming and labor-intensive. Therefore, this paper proposes an automatic measurement method for the cable shape of suspension bridges: (1) For obtaining target during the construction process, inertial navigation and differential Global Positioning System fusion and route planning method are adopted in combination with airborne laser scanning to get fine point clouds. (2) Addressing the challenge of large-scale point clouds segmentation, SCF-Bridge-Net is proposed based on Spatial Contextual Features Net (SCF-Net) and suspension bridges point clouds simplification method, enabling spatial positioning of the cable clamp and rapid automated calculation of geometric information. The proposed method is successfully applied to the Xianxin Road Bridge in China. The results show that the average error of the main cable shape is 1.1 cm, and the angle error of the cable clamp is approximately 0.21°, validating the efficiency and reliability.