Axial compression ratio limit for self‐centering precast segmental hollow piers

Abstract

Axial compression ratio limit was investigated for self‐centering precast segmental hollow piers based on post‐earthquake residual axial loading capacity. The analytical method of unbonded posttensioning tendons (PT) stress increment and the simplified method of compression zone height were developed and validated by the finite element model verified by experiments. An analytical formula was deduced to calculate the critical axial compression ratio, which was regarded as the limit and can be obtained when the capacity provided by the noncompression zone at the bottom is equal to the initial axial compression loading. Parameter analysis was conducted to study effects of eight common design parameters on the critical axial compression ratio. The conclusions are summarized that there is good accuracy between the proposed methods for both unbonded PT stress increment and compression zone height and the finite element analysis. The axial compression ratio limit is proposed to be 0.25 when the ratio of energy dissipation (ED) bars is <1.5%. It is an inadvisable solution that more ED bars are matched with higher initial tensioning force of unbonded PT to fulfill the precast segmental piers with good ED capacity and self‐centering capacity in practice.