Experimental and Numerical Study on the Seismic Performance of Self-Centering Isolated Piers

A self-centering isolated pier (SIP) with an elliptical rocking interface is proposed to enhance the seismic performance of bridge piers. Pseudostatic tests were conducted on two SIPs (one with and the other without tie bars) to study their damage patterns and hysteretic characteristics. Additionally, a finite-element model of a SIP was constructed to study the effect of SIP parameters on its hysteretic characteristics, such as the long radius of the ellipse, the ratio of the long to the short radii of the ellipse, the distance from the tie bar to the centerline of the pier, and the axial compression ratio. The results indicated that the pier bodies of the two SIPs are in the elastic stage. Increasing the long radius of the ellipse and axial compression ratio can enhance the hysteretic characteristics of the SIP. However, these larger values could lead to yield failure of the pier bottom. Furthermore, an increase in the ratio of the long to the short radii of the ellipse results in a progressively less plump hysteretic curve for the SIP, leading to a reduction in energy dissipation capacity. Nevertheless, an increase in this ratio can improve the self-centering ability of SIPs. The distance from the tie bar to the centerline of the pier has little effect on hysteretic characteristics of the SIP.