Dynamic behaviors of steel multiple-rocking-column structural system with rocking stoppers

This study investigates dynamic behaviors of an innovative steel multiple-rocking-column structural system consisting of continuous beams, layered columns and rocking stoppers with rotation thresholds. If the rotation threshold is exceeded, rocking motion of the columns at the same level will be stopped and potential overturning of the whole structure is thus avoided. When the columns rock within the rotation threshold, the lateral stiffness is much smaller than that of the corresponding rigidly-jointed structure, the structural weight provides a self-centering force, and the internal forces of the structure can be maintained at a lower magnitude to minimize structural damage. Characteristics of the proposed system are different from stacked block systems and controlled rocking systems. A three-story representative structure is designed to investigate characteristics of the proposed system, based on a previous study of a corresponding single-story one. An equivalent rectangular column model is established, exhibiting a highly nonlinear relationship between the inter-story shear force and drift. Small-scale shaking table tests are conducted on 1:10 scaled models of the proposed system and the corresponding rigidly-jointed frame system. Modal identification and analysis are employed to investigate the equivalent modes, frequencies and participation factors of the experimental results. Energy features and force reduction effects of the proposed system are verified through numerical simulations.