Three-dimensional geometric nonlinear analysis of composite cable-stayed bridges using a refined double-beam model

In this paper, a refined double-beam finite-element model is constructed for composite cable-stayed bridges. Using this refined model, the authors aimed at performing more accurate three-dimensional (3D) analyses of cable-stayed bridges by considering all the geometric nonlinearities, including large 3D rotation issues, using catenary cable elements for cables, and taking into account member eccentricities between cable anchor points with the deck and member neutral axes. To consider member eccentricities and avoid using rigid links to connect the eccentricities, a validated two-step procedure is developed to transfer member forces and stiffness from the fluctuating neutral axis lines to a straight reference line. Through a numerical example, the effect of member eccentricity is discussed, and it is clearly shown that member eccentricity has a larger influence on displacements and bending moments than on modal responses. Through a detailed comparison example with previous research and existing software, the refined model presented in this paper demonstrates higher accuracy.