Application of Viscoelastic Dampers for Seismic Retrofitting of Existing Reinforced Concrete Buildings

Passive control systems that provide both stiffness and energy dissipation, such as viscoelastic dampers (VEs), offer a promising strategy for seismic retrofit of existing reinforced concrete (RC) buildings, especially critical facilities that must remain operational during construction. Unlike conventional retrofit methods that require concrete casting and occupant evacuation, VE-based systems can be installed with shorter construction periods and reduced environmental disturbance. This study experimentally investigates the dynamic behavior of VE material subjected to large shear strain amplitudes of 300% and 400%, the latter exceeding typical design limits, to clarify its performance under severe seismic demands. The test results are used to calibrate a numerical model that represents the stiffness and energy-dissipation characteristics of the VE over this strain range. The calibrated model is then implemented in the seismic retrofit design of a six-story RC hospital building and evaluated through nonlinear structural analyses. The results indicate that the proposed VE retrofit scheme can achieve the targeted performance objectives and demonstrate the feasibility of applying high-strain VE dampers in practical seismic retrofit projects.