# Review of the Main Cable Shape Control of the Suspension Bridge
## 3 Construction Control Technology of the Main Cable  
### Construction Methods  
The main cable construction approaches of a suspension bridge are the air spinning (AS) and prefabricated parallel wire strand (PPWS) methods. The AS method takes the steel wire as the traction unit, multiple wires are made into a strand in the catwalk, and then multiple strands are bound to form the main cable. Different from the AS method, the PPWS method takes the cable strand as the traction unit, and then strands are bound to the main cable. The AS approach has been broadly utilized in the United States and Europe, and the PPWS method has been extensively employed in Japan [57; 58]. China has mastered the PPWS's \"section technology\" [4] by referring to Japan. (1) AS method  
The study of the AS approach has had a long history in Europe and America, but there are few practical engineering cases built in recent years, which leads to little relevant information being available. Most suspension bridges in China are built on the basis of the PPWS approach for the main cable \"section\", and there are few investigations on the AS method. The Yang Baoshan Bridge completed in 2022 is the first bridge constructed by China independently using the AS method, which is of great significance. The main cable's construction principle and the technology of the AS method for the Yang Baoshan Bridge were reported by [PERSON] et al. [59]. It was pointed out that as the main cable was erected, the wire was released by the unreeling machine, and the constant tension of the wire was adjusted by the tension tower. The steel wire was driven back and forth between the two banks by a spinning wheel, thus carrying out wire \"section\" operations. When the spinning wheel reaches the strand shoe position on both sides, the workers pull the steel wire out of the spinning wheel and hang it on the strand shoe, repeating the above operation until the single strand was erected. The basic principle of \"section\" has been demonstrated in Figure 8. Since the 21 st century, suspension bridges have been also rapidly developed in Republic of Korea. [PERSON] et al. [60] introduced some improvement measures in the process of \"section\" the main cable using the AS method at the Yi Sun-Shin Bridge in Republic of Korea, focusing on the improvement of the spinning wheel to effectively avoid wire \"derailment\" during the \"section\" process. To efficiently erect the main cable for long-span suspension bridges, the AS and PPWS technologies and associated equipment were currently being developed in Republic of Korea, based on a report by [PERSON] et al. [5]. [PERSON] et al. [61] briefly reported the \"section\" methods and technical characteristics of five types of suspension bridges in Republic of Korea. Figure 8: Construction principle of the AS method. 2. PPWS method  
PPWS is an approach of transporting prefabricated parallel high-strength steel wire strands to the site for installation. The main procedures of the PPWS method have been presented in Figure 9. [PERSON] et al. [62] reported the latest development and application of high-strength prefabricated parallel steel wire in Republic of Korea. The development and application process of high-strength PPWS strand were mainly introduced, including the test results of the strand performance test. The production system of the PPWS was also introduced, and the key points of its production equipment and production process were expounded. Recently, a 1960 MPa grade steel wire cable strand [2] was created in China, and it was successfully used on the Nansha Bridge. The excellent mechanical properties of the strand were investigated through tests and numerical analysis. The AS and PPWS approaches have different characteristics. The suitable main cable erection method should be selected based on the needs of the features of the construction conditions, the main cable quality, construction period, and cost requirements.