Shaking table study of seismic performance and retrofit effectiveness for rammed earth structures with precast concrete tie columns

Abstract

This paper proposes a rammed earth (RE) structure with precast concrete tie columns. The structural system places tie columns at wall corners, together with horizontal tie bars and shear keys at compacted layer interfaces, forming a collaborative system to improve seismic performance. To investigate the seismic behavior of this RE structure, shaking table tests on a 1/2-scale model were conducted. Test results showed progressive damage development under strong seismic actions, with stable stiffness degradation observed throughout the loading process. The structure achieved the fortification objective of “no collapse under major earthquakes”, indicating satisfactory seismic performance of the structural system. Furthermore, this paper proposes a retrofit method using high-strength steel tie rods for earthquake-damaged structures. This approach achieves rapid strengthening by providing effective global confinement to damaged walls. Shaking table tests on the retrofitted structure showed that the retrofit components helped slow the stiffness degradation of the tested earthquake-damaged structure, while also contributing to restraining wall damage development and global deformation. Through two shaking table tests, this study verifies the seismic performance of the proposed RE structural system and the effectiveness of the rapid post-earthquake retrofit method. The findings provide a valuable reference for improving the seismic safety and post-earthquake resilience of traditional RE structures.