Seismic improvement of structures using hybrid self-centring dampers and rocking core

Abstract

Extensive research on seismic-resistant systems aims to lower earthquake repair costs and downtime. This article presents a novel low-damage self-centring system that aims to improve the seismic resilience of buildings by enabling controlled rocking motion while reducing the risk of overturning. Significantly, the rotational movement can be entirely restored. This system combines a rocking core with damping devices, including disc springs and peripheral slit dampers. In this hybrid system, two damping devices are mounted to both first-floor columns of the rocking bays and the rigid movement of the rocking core triggers the dampers. Firstly, a comparative investigation was conducted to assess the efficacy of the endorsed hybrid system. The cyclic pushover results showed that the hybrid system is superior to other typical bracing systems in energy dissipation, with a five times higher margin. In addition, by employing the suggested system, the frame's drift ratio profile under nonlinear time history analysis (NTH) remained consistent throughout the structure, indicating its ability to withstand the soft storey mechanism. Secondly, a comprehensive assessment was conducted on the proposed system's collapse using incremental dynamic analysis (IDA) took into account various seismic intensities and engineering demand parameters for buildings with different bay lengths and included low, medium, and high-rise structures. The system's flag-shaped behavior and self-centring capability were confirmed by the average residual drift ratio of approximately 0.03% (almost zero) for all examined structures. Also, the collapse performance of the system exhibited a safety margin against collapse, with an average of 1.9 across all buildings and seismic intensities.