Nonlinear vibration of biaxially excited R/C columns

In the present study, the instantaneous stiffness matrix of an R/C column with effects of shear deformation and axial load being considered has been constructed by using finite segment method. In addition, the effect of bond slip is considered by applying the concept of semi-rigid joint to modify the stiffness matrix of the column.Pacoima Dam earthquake data is used as excitation in computation of R/C columns subjected to ID or 2D severe earthquakes. It is found that the displacement and strain responses of columns to 2D excitations are greater than those of columns to ID excitation. The effect of bond slip at lower end of column is obvious for the case of columns to 2D excitations.