## 2 Hanger Bending Damage and Suspended Lateral Bracing  
### Hanger Bending Damage During the Configuration Transformation  
During the spatial configuration transformation of the main cable in a self-anchored suspension bridge, there is a significant lateral position difference between the main cable in the FHC and FLC. The tensioning process of hangers involves complex interactions between the main cable, tower, and girder system. As the main cable and hangers are progressively tensioned, the cable and cable clamps undergo longitudinal, vertical, and lateral displacements [8]. However, since the installation angles of the cable clamps and conduits are designed based on the FLC, the tension line between the upper and lower anchor points of the hangers deviates from these angles during construction. This deviation can cause angle deviation between the hanger and the cable conduit, which, when exceeding a certain threshold, results in severe bending damage to the hangers at the cable clamps or the anchorage box conduits. This issue represents a critical challenge during the configuration transformation process of self-anchored suspension bridges, particularly in the early stages of tensioning when the main cable is still adjusting to its final configuration. This section analyzes the causes of hanger bending during the classic \"Erect Cable Before Girder (ECBG)\" and \"Erect Cable After Girder (ECAG)\" construction methods. In the ECAG method, the main girder is typically installed using temporary supports. After the girder is erected, the main cables are installed and the hangers are tensioned, completing the configuration transformation. As shown in Figure 1a, during the configuration transformation, the position of the main girder and its cable conduit remain fixed. The hangers are temporarily pulled using an extension rod during tensioning, and the extension rod is removed once the configuration transformation is completed. However, due to the lateral position difference between the FHC and FLC, significant lateral angle deviation occurs during initial hanger tensioning. This angle deviation may prevent the extension rod from properly inserting the hangers into the conduits, causing hanger bending damage at the cable clamps or anchorage box conduits. In the ECBG method, the main cables are installed first, followed by the hoisting of the main girder and its connection to the hangers. During this process, the position of the cable conduits moves with the main girder. Since the extension rod cannot be used in this method, the girder must be raised until the lower ends of the hangers can connect to the cable conduits. As shown in Figure 1b, as the main girder is raised, the lateral angle deviation between the upper and lower anchor points of the hangers increases. This can  
Figure 1: Lateral bending damage of hanger during configuration transformation. cause severe bending damage, particularly for the shorter hangers located in the mid-span, where the length of the hangers may be insufficient to reach the cable conduits. In the FLC, \(d\) and \(L\) represent the vertical and horizontal distances between the hanger's upper and lower anchorages, respectively. The vertical and horizontal displacements of the upper anchorage in the FHC relative to the FLC are denoted by \(\Delta Y\) and \(\Delta Z\), while \(L_{d}\) corresponds to the hanger's unstressed length. The lateral deflection angle \(\Delta\theta\) quantifies the transverse angle deviation during construction. Furthermore, as the hangers are progressively tensioned, the tower experiences longitudinal displacement, and the cable clamps move longitudinally with the main cable. This movement results in the development of a longitudinal tilt angle between the upper and lower anchor points of the hangers, as shown in Figure 2. The tilt angle increases as the hanger length decreases, and short hangers in both the side span and the main span experience significant longitudinal tilt.