Influence of wall thickness on the seismic performance of thin-walled precast UHPC hollow piers

Abstract

Conventional precast piers made of normal concrete (NC) typically feature a solid section, which may hinder hoisting and transportation during construction. Given the superior properties of ultra-high-performance concrete (UHPC), replacing the NC solid section with a UHPC hollow section presents a viable alternative. However, the seismic performance of thin-walled piers will be different from the solid piers. Current research on the seismic performance of hollow piers primarily focuses on cast-in-place (CIP) piers made of normal concrete, which generally have thick walls and a hollow ratio <0.4. The exceptional mechanical properties and fluidity of UHPC make it feasible to reduce wall thickness in hollow piers. Nevertheless, studies specifically investigating the seismic performance of UHPC hollow piers remain limited. This study presents an experimental investigation of four precast piers with varying wall thicknesses—three made of UHPC and one made of NC as a reference. Quasi-static tests were conducted and the hysteretic responses, energy dissipation, residual displacement, and curvature distribution were discussed. Finally, a refined numerical model was developed on OpenSees platform to accurately replicate the hysteretic and skeleton curves of each specimen. Parametric and time-history analyses were conducted under six strong near-fault ground motions. The results revealed that wall thickness had a limited effect on the strength and residual displacement of UHPC hollow piers, but significantly influenced cumulative energy dissipation and stiffness degradation. The UHPC pier with a hollow ratio of 0.36 exhibited the best strength and displacement responses among all specimens.

This research is supported by the National Key Research and Development Program of China (No. 2019YFE0119800), the China Scholarship Council (CSC), during a research stay of the first author in the Universitat Politècnica de Catalunya. The third author acknowledges the support of research projects TED2021-130272B-C21 funded by MCIN/550 AEI/10.13039/501100011033 “European Union Next Generation EU/PRTR” and PID2021-123701OB-C21, funded by MCIN/AEI/10.13039/501100011033 and European Regional Development Funds (ERDF) “A way to make Europe”.

Peer Reviewed

Postprint (author's final draft)