Full‐Scale Shaking‐Table Evaluation of a Controlled Multiple‐Rocking‐Column System for Low‐Damage Seismic Performance

Abstract

The growing demand for rapid post‐earthquake functional recovery and minimal structural damage has promoted the development of low‐damage seismic design strategies. Controlled rocking systems have emerged as an effective seismic structural solution for enhancing seismic resilience. To provide experimental evidence for the development of resilient steel structures, this study presents a full‐scale Controlled Multiple‐Rocking‐Column System (CMRCS) developed as part of the RObust BUilding SysTem (ROBUST) project. The system comprises two exterior controlled multiple‐rocking‐column frames and a central low‐damage secondary frame. The secondary frame carries the gravity loads assigned to Grid 2 and provides supplemental lateral resistance. Low‐damage rocking joints are installed at both ends of the rocking columns at each storey. Under frequently occurring earthquakes (FOEs), the CMRCS is designed to behave similarly to a conventional moment‐resisting steel frame, while the multiple‐rocking mechanism is intended to be activated at higher seismic intensities. Full‐scale shaking‐table tests were conducted on a 3‐storey steel frame specimen subjected to ground motions with peak ground accelerations (PGAs) ranging from 0.055 g to 0.62 g. The test results demonstrated that the structure exhibited satisfactory seismic performance, characterized by negligible residual drifts and no visible damage throughout the test sequence. Moreover, the proposed system also satisfied the immediate occupancy performance objective even under very rare earthquake‐level excitation (PGA of 0.62 g), thereby confirming the effectiveness, robustness and seismic resilience of the proposed system.