Analysis Of Anchorage Zones In The Long-span PC-box Girders

To increase the tensioning force in a single tendon, various new types of special anchorage devices are adopted in the bridge engineering. The stress distributions of the related anchorage zones are complicated. The safety and the crack resistance of the anchorage zone which exists due to the usage of large tonnage anchorage device, are the critical part of the structural design. Because there is no reliable method to calculate the strength and crack resistance of the anchorage zone for this type of device, careful theoretical analysis and physical test must be carried out.A study of the stress and strain distribution of anchorage zone in a long span PC box girder was undertaken in the background of Hangzhou Bay Bridge project.First, a refined 3D linear finite element model of the PC box girder had been established. The accuracy of the analytical results of the model had been checked through the comparisons to the results of the field measurement which was carried out during the tensioning process at the stage of the girder construction. Good agreement was found between the theoretical and experimental strain values. Meanwhile, a comparison between the single anchorage model and the box girder model was made, the similarities of the stress distribution showed that the linear response of the single anchorage model was accordant with the box girder model.Second, liear finite element analysis and nonlinear finite element analysis of the single anchorage model were both carried out. ABAQUS's concrete damage plasticity model was used during the simulation of the whole loading process of the single anchorage model, the variation of stress distribution in the concrete was investigated.Third, parametric studies using elasto-plastic finite element method were undertaken to provide some good advices for structural designs of anchorage zones.