POST-TENSIONING THE CONNECTION REGION OF PRECAST POST-TENSIONED BRIDGE GIRDERS FOR CONTINUITY

Abstract

In the study, a precast post-tension concrete girder was tested to examine the behavior of the structure before and after continuity and to evaluate the effectiveness of post-tensioning for continuity to resist positive and negative moments in the connection region. The initial stresses were measured in a concrete bridge constructed using simple support precast post-tension girders that achieved continuity by strengthening the girders through post-tensioning the top of the girders at the connection region. The initial stresses were calculated before and after continuity to examine the effects of continuity on prestress levels. The stresses were calculated at the continuity diaphragm to investigate the effect of post-tensioning on continuity moments. A 3D finite-element model was developed via ANSYS to simulate the performance of the precast post-tension concrete girders. In order to achieve continuity, five forms were compared, and the results indicate that post-tensioning for continuity leads to an increase in the compression stress on the sections. The mid-span stress–strain curve results also show that an increase in the load-carrying capacity for models achieves continuity through post-tensioning. The method used to achieve continuity as described throughout the study presented a stiffer response when compared to that of the other forms of continuity.