The article discusses how to control the construction of the south main bridge of Xiazhang Sea-Crossing Bridge. The researchers studied methods for building the bridge sections, closing side spans, and closing middle spans of composite girder cable-stayed bridges. They found that tensioning stay cables twice, casting wet joints one section behind girder casting, and controlling the installation of main beams were crucial processes. To ensure smooth closure of side spans, they used counterweights, adjusted cable forces, and jacked up girder sections. For middle spans, they used a cooling closure method with special plates. By calculating temperature differences and closure spacing, they determined the size of the plates and length of closure sections.