Remote estimation of cable tension using catenary theory and point clouds obtained by terrestrial laser scanning

This study addressed the structural health monitoring of civil engineering cable structures, in which single cable tension is the key parameter influencing safe and intended behaviour. Traditional methods for monitoring the tension force in a cable are labour-intensive and require direct interaction with the cable. In contrast, the proposed approach provides a remote and rapid assessment of the tension force in the cables of engineering structures using only the shape of the cable. First, a terrestrial laser scanner was used to acquire a point cloud of the cable geometry from a distance. Catenary theory was subsequently applied to the point cloud data to calculate the theoretical tensile force in the observed cable. When the results were compared with those obtained through conventional direct measurements using a dynamometer, the differences were negligible. The proposed approach was subsequently demonstrated on the actual in-service overhead contact lines of a tram system. The results indicated that the precision of the proposed approach is highly dependent on the accuracy of the data describing the physical properties of the cable (cable linear mass). Thus, the proposed approach was proven to be precise, reliable, and rapid, and directions for future research were discussed accordingly.