Experimental investigation on lateral resistance capacity enhancement effect of a self-centering shape factor in self-centering pier systems

Abstract

In self-centering (SC) pier systems, a rocking interface is typically employed at the bottom of a pier to achieve a gap-opening mechanism. However, compared with the full-section bending state of the bottom section of a ductile pier (DP), the local compressive state of the rocking interface in the SC pier inevitably leads to a significant reduction in the lateral resistance capacity. Although a prestressing tendon (PT) force can improve the lateral resistance capacity, it also induces local damage. Moreover, its enhancement effect is limited, particularly in the case of a column with a high axial compression ratio. Therefore, this study proposes an innovative measure to significantly improve the hysteretic performance of an SC pier without inducing additional damage, which is to raise the location of the rocking interface. First, the SC shape factor ξSC is innovatively defined to quantify the above-mentioned measure, and its working mechanism is investigated in detail in this study. Second, a high-lateral-resistance SC pier system (HLRSCP), which applies the concept of ξSC, is proposed and introduced for its advantages. Third, hysteretic tests of the DP and HLRSCP with high axial compression ratios are performed and analyzed. Finally, the enhancement effect of ξSC on the lateral resistance capacity is parametrically examined using a finite element model, and the feasible region of ξSC is inferred and presented. The results validate the effectiveness and feasibility of the concept of the SC shape factor in improving the hysteretic performance of the SC pier system.