Determining the Completed Bridge State of a Self-Anchored Suspension Bridge: A Noniterative Analytical Approach

The calculation of the completed bridge state (CBS) for self-anchored suspension bridges (SASBs) has long been a focal point in both academic and engineering communities. Most existing methods rely on complex iterative computations and manual adjustments, resulting in cumbersome solution processes. To address this issue, this paper proposes a novel method based on design parameters such as control point coordinates (anchor points and IP points, where the main cable in the side span intersects with that in the main span), sag-to-span ratios, and hanger spacings to establish expressions for internal forces and deformations throughout the entire bridge using a set of fundamental unknowns. By simultaneously considering closure conditions, static equilibrium conditions, and zero vertical deflection constraints at hanger points, a closed system of nonlinear equations strictly matching the number of fundamental unknowns is formulated. Solving this nonlinear equation system simultaneously obtains bridge alignment and internal force distribution; the CBS of the SASB is thereby determined. The proposed method has clear physical meanings and can effectively avoid complex iterative computations and manual adjustments. To validate the method's universality, five comparative cases encompassing multidimensional parameters, hanger configurations (linear/catenary), and self-weight combinations are analyzed, with engineering accuracy confirmed through finite-element software verification.