Analytical and Experimental Study of Tuned Rocking Walls for Seismic Control of Existing Buildings

ABSTRACT The tuned rocking wall (TRW) is a novel passive control system that functions as a nontraditional tuned mass damper (TMD) developed to improve the seismic performance of existing buildings. The system is composed of a rocking wall with either a pinned or stepping base configuration, externally attached to a specific storey of the building via a viscoelastic device optimized to suppress structural motion. This study conducts both analytical and experimental investigations into the optimal design and seismic control performance of the TRW. The equations of motion for a multi‐degree‐of‐freedom (MDOF) structure coupled with the TRW are formulated, and a reduced‐order two‐degree‐of‐freedom (2‐DOF) model is derived for design purposes. Optimal TRW parameters are obtained numerically using two design methods based on harmonic and white noise excitations. Additionally, closed‐form expressions are derived for the white noise case. Unidirectional shaking table experiments are conducted on a three‐storey shear‐type model to validate the TRW's implementation and perform a parametric analysis. The results confirm the TRW's effectiveness in suppressing both peak and root‐mean‐square responses under both optimization methods. The control performance is primarily governed by the product of the mass ratio and inertia factor, following a second‐order polynomial function. The TRW shows low sensitivity to moderate variations in its damping ratio, but greater sensitivity to frequency deviations; however, effective control is maintained if the frequency shift remains within 20%. Finally, the analytical model is validated against experimental results, confirming its accuracy in predicting structural responses and suitability for further parametric studies.