Deformation controlled nonlinear analysis of prestressed concrete continuous beams

A finite element model, based on a curvature increment technique, is applied to the nonlinear analysis of prestressed concrete continuous beams. The computer model is capable of predicting the response of such beams over the entire loading range from precracking to the collapse stage. Nonlinearity is included in the model by means of a stepwise linear analysis technique, which makes use of the relevant secant stiffnesses obtained from the moment-curvature relationships for segments along the length of the beam. The use of curvature, as opposed to load, as the incrementing parameter facilitates the analysis of a beam with limited ductility, in which critical regions soften before failure occurs. A parametric study carried out to determine the optimum layout of the segments for the model is described. The optimum mesh is used in the analysis of a number of beams and the results are compared with test data and other analytical predictions. It is concluded that the macroscopic finite element model gives an adequate prediction of the behavior of a continuous prestressed concrete beam over the entire range of loading up to failure.