Methods to correct unstrained hanger lengths and cable clamps' installation positions in suspension bridges

In this paper analytical methods to correct the unstrained hanger lengths and cable clamps' installation positions in suspensions bridges are proposed, based on the elevation error of the unloaded cable and the dead load error. After calculating the unstrained cable length and correcting hanger tensions, the main-cable configuration in the completed bridge state was recalculated. Then the elevations of the main cable at the suspension points and the unstrained lengths of cable segments were determined. The former can be used to calculate the strained length of each hanger, which together with the corrected hanger tensions determine the corrected unstrained hanger lengths. While the latter can be used to calculate the horizontal length of each cable segment in the unloaded state. Then the horizontal distance from each cable clamp to the pylon centerline in the unloaded state is calculated, which is helpful to the positioning of each cable clamp. In the proposed methods, nonlinear equations are solved with the generalized reduced gradient (GRG) algorithm, making the procedure simplified. The feasibility and validity of the proposed methods are demonstrated through a numerical example.