This project systematically studied and designed the reasonable cross-sectional form of the wide span main beam of a large-span prestressed concrete partially cable-stayed bridge, summarized the mechanical performance of the box shaped main beam with a large cantilever stiffening diaphragm, and proposed targeted durability and crack prevention measures for the wide span main beam; We have developed a new unilateral bidirectional anti slip anchoring system for some cable-stayed bridges, and conducted a single steel strand replacement test by simulating a real bridge, which can truly make the cable-stayed cables of some cable-stayed bridges replaceable and detectable