Comparative Research on Anti-seismic Capability and Its Influencing Factors of Bridge Columns

In this paper, the anti-seismic capacity and its influencing factors are investigated for the typical bridge columns.The nonlinear constitutive relationships of materials are used to establish the moment-curvature relationships of the column plastic hinge region.Effects of axial compression ratio, longitudinal reinforcement ratio, and transverse reinforcement ratio are examined on the flexural capacity and ductility of the column.Following the codes of AASHTO, CALTRANS, ATC-32 and guidelines for seismic design of highway bridges, the shearing resistance capacity and the rotational capacity of the plastic hinge are compared for the column.The results show that the increase of axial compression ratio and longitudinal reinforcement ratio will increase the flexural capacity of the column, but will decrease the column ductility.Increase of the transverse reinforcement ratio can effectively increase the flexural capacity and the ductility of the column, and the increase is getting slower while the transverse reinforcement ratio is reaching higher.The method provided in the guidelines for seismic design of highway bridges for calculating the shear resistance capacity and the rotational capacity of the column is shown to be too conservative, whose calculation values are much lower than those of other codes.