Construction monitoring of cable replacement: a case study

To ensure the structural safety and normal operation of a cable-stayed bridge in China (Rainbow Bridge), cables were replaced and construction monitoring and control were conducted. In the process of cable replacements, the cable force and girder elevation were monitored and the distribution of cable force was adjusted according to the construction monitoring results to improve the structural force and increase the safety reserve of the structure. In the process of monitoring the cable force, the difference between the measured cable force and the design cable force was 0.4–4.4%. After adjusting the cable force, the difference between the measured cable force and the design cable force was less than 2%, and the change in the cable force was uniform, meeting the original design requirements. In the monitoring process of the main girder elevation, the elevation was increased by a maximum of 0.054 m. After completing cable adjustment, the main girder elevation was increased by 0–5 mm. This elevation was more reasonable and met the design requirements.