Performance-oriented design of overload-protected viscous dampers for adjacent structures

The application and performance-oriented parameter optimisation of an overload-protected viscous damper (OP-VD) are investigated in this study to mitigate seismic responses and prevent excessive force transmission between adjacent structures. Within a performance-based seismic design framework, the damper parameters are systematically optimised to ensure that multiple response objectives are satisfied under varying seismic intensities. The OP-VD integrates a frictional overload protection mechanism with viscous energy dissipation, enabling an adaptive control strategy. This design ensures that damper forces are effectively capped under strong ground motions, while sufficient damping is provided under moderate excitations to control inter-storey drift and absolute structural acceleration. The mechanical characteristics and working principle are first clarified through detailed implementation and simulations. Subsequently, a coupled dynamic model of adjacent structures interconnected by the proposed damper is established for non-linear time-history analyses. Numerical simulation results demonstrate that under severe seismic inputs, the OP-VD successfully limits force transfer by way of the activation of the overload protection mechanism, thereby preventing structural overloading. In contrast, under moderate excitations, the viscous component dominates, leading to enhanced vibration attenuation. Consequently, the device achieves a balanced control of drift, acceleration and force demands, ensuring both structural safety under rare earthquakes and serviceability under frequent events.