Coupled nonlinear and time-dependent analysis for long span cable-stayed bridges

This paper proposes a new cable element and a novel formation procedure of unbalanced loads for cable-stayed bridges. The proposed method couples the effects of geometric nonlinearity and concrete creep/shrinkage. An improved catenary cable element with arbitrary rigid arms is introduced to reduce the degree of freedoms in simulations. An explicit expression of tangent stiffness of the new cable element is derived. Then, an incremental stiffness equation under co-rotational coordinate system is established by introducing a recurrence equation of creep loads. Following this, a new formation method is proposed to evaluate the unbalanced loads on the current deformed equilibrium configuration. This method is illustrated and validated by two actual long span cable-stayed bridges in Yangtze River. The results indicate that the coupled algorithm can significantly enhance the computational efficiency and accuracy for the bridge analysis during construction.