Nonlinear rocking dynamics of pre-tensioned single rigid blocks under harmonic base excitation

The rocking mechanism has been widely recognized as a beneficial technique to reduce structural damage arising from lateral excitations particularly earthquake loading, and hence, segmental pre-tensioned bridge piers have been recently emerged due to their self-centring property accompanied by accelerated construction of such structures. Hence, this study formulates the rocking dynamics of tied pre-tensioned single rigid blocks as an initial study for better understanding of dynamics of segmental pre-tensioned bridge piers. The nonlinear equation of rocking motion is then numerically solved under different range of base harmonic excitations. To achieve this, the rocking initiation condition is considered to determine initial conditions of rocking motion, an implicit solution is adopted to solve the equation of rocking motion and determine rocking response. Finally, a study is performed on a specific composite tied block to investigate effects of geometry and initial pre-tensioning force of the cable on the dynamic behaviour of the block. This study can find use in better understanding of segmental pre-tensioned columns. (paper)