LOADING BEHAVIOR AND REINFORCEMENT DESIGN OF ANCHORAGES OF EXTERNAL PRESTRESSED BRIDGES

Based on the behavior analysis of two external pre-stressing concrete bridges with different cross section, three dimensional stress distribution characteristics of anchorages were obtained and the weakness of anchorages was indicated. In addition, the influence of angle iron, steel tie plate, external pre-stressing steel tube, was analyzed. Based on the loading transmitting path combined with strut-and-tie model, this paper proposes the strut-and-tie models for the reinforcement calculation of anchorage, and corresponding design suggestions. Analysis shows that the angle iron placed at the connection of the anchorages and girder effectively reduces the stress concentration caused by the huge tensile force. Considering material nonlinearity and the contributions of such members as the angle iron, steel tie plate, external pre-stressing steel tube, reinforcement web, and distributed reinforcement, the concrete stress of anchorage is reduced significantly.