Segments arrangement effect on improvement of self-centering PPS piers seismic performance

Abstract

Abstract In bridge engineering, the use of precast post-tensioned segmental (PPS) piers is increasingly expanding due to the Accelerated Bridge Construction viewpoint. Recent experimental and numerical researches have studied general seismic performance and nonlinear behavior of PPS piers without much attention to segment arrangements or joint openings. The aim of this paper is to utilize innovative segment arrangements to reduce the residual deformation, and also enhance the energy dissipation capacity of PPS piers with internal energy dissipation (ED) bars. For this purpose, nonlinear rocking dynamics of a multiple-block assembly of tied rigid rocking blocks equipped with ED bars at joints are firstly developed so that uplift moment for each joint is derived to obtain the threshold joint opening height (height above which no joint opens). Then, nonlinear static, quasi-static, and dynamic analyses are conducted on different segment arrangements of finite element models of PPS piers. It is proposed to place more segments within the threshold joint opening height by using unequal segments so that the total rotation is shared among critical joints (joints that open), and the nonlinear extent of ED bars at the bottom joint is reduced, resulting in the reduced residual deformation. It is also proposed to place a lower ratio of ED bars at the critical intermediate joints or place ED bars of a lower yield stress there so that the intermediate joints can be more effective even with small rotations. Results indicate that using the proposed segment arrangement, enhances both seismic and post-seismic performance of PPS piers.