Abstract
Using a model for external-tendon-type simple-girder, continuous-girder, and continuous-rigid-frame prestressed-concrete bridges, an analysis was carried out, taking into account their material nonlinearity and geometrical nonlinearity. Based on these results, a simple calculation formula is proposed for the amount of increase in stress on the external tendons, for use in computing the flexural capacity. A nonlinear analysis was carried out for structures in which an existing simple-girder bridge was converted to continuous-girder through reinforcement with external tendons in order to improve the load force and travel performance. It was found that the safety with respect to flexural failure is adequately satisfied due to the fact that a considerable redistribution of moment occurs.
