Study of seismic performance of reinforced concrete rocking columns

A type of reinforced concrete (RC) rocking columns using steel plates as the end protection was proposed in this study. Five specimens including one conventional RC column and four RC rocking columns were tested under cyclic loading. The experimental results show that compared with conventional RC columns, the load-bearing capacity and energy dissipation capacity of RC rocking columns decrease. However, there is a significant reduction in residual deformation and damage to rocking columns. As the axial load increases, the load-bearing capacity of RC rocking columns increases as well. The initial stiffness of rocking columns is similar to that of conventional columns under the same axial load, before gap opening occurs at the column-base interface. Subsequently, an analytical method for estimating the load-bearing capacity of rocking columns was developed, based on four critical limit states. The calculated load-bearing capacity agrees well with experimental results, verifying the effectiveness of the proposed analytical method in accurately predicting the mechanical behavior of this type of column.