Abstract: To address the difficulties caused by dense end nodes and restricted working spaces in elevated sections, this paper proposes a terminal fixing device with dual protection consisting of a screw clamp and an elastic rope, and establishes a torque-angle calibration procedure to achieve standardized tightening and self-locking. The results show that the technical solution proposed in this study reduces the single installation time from 12.4 minutes to 3.7 minutes, decreases the cycle time by 70%, and improves the reliability from 94.6 to 99.8. The tension fluctuation is controlled within the specified ±10 supervisory limit, and the temperature rise of the outer shell meets the requirements of the national standard.