Abstract: By means of applying the analysis method of increment linearization, taking externally prestressed structure with tilted belly poles as investigation object,and establishing cable element model, the tangential stiffness matrix of the displacement increment of the cable node and the elongation-shrinkage increment array of the belly poles are found for the structure by using its geometric, physical, and balancing relation. The tangential stiffness matrix of foregoing structure will be correlated not only with the parameters of the cable elements such as Young's modulus, cross-sectional area, original length, and current parameter but also with the current paramer of the belly pole. Newton-Raphson's increment iteration method is used to compile a computation flow of cable node displacement. The analysis of geometric nonlinearity of poles-to-cable coupling in externally prestressed structure with tilted belly poles will provide a theoretic bases for reinforcement design of combined structure with tilted belly poles.

Key words: structure reinforcement, external prestress, tilted belly poles, geometrically nonlinearity