Experimental and numerical investigations of replaceable moment-resisting viscoelastic damper for steel frames

An innovative type of replaceable moment-resisting viscoelastic damper (RMVD) was developed to increase the level of inherent damping of steel moment frame buildings to control wind-induced and/or earthquake-induced dynamic vibrations. The RMVDs are installed in lieu of existing steel moment connections, which occupies no additional architectural space. The system level damping of the steel moment frames could be increased from the viscoelastic segment of the RMVDs. Besides, the proposed damper exhibits passively adaptive performance. The energy dissipation mechanism of the RMVD could be easily shifted between the viscoelastic segment and fuse segment under different levels of inter-story drifts. The sacrificial fuse segment of the damper, which could be easily replaced after an earthquake event, provides ductile and stable performance when the inter-story drifts exceed a predefined threshold. The paper first presents a systemic investigation of the performance of viscoelastic material. Then, a series of dynamic experimental studies were carried out on the viscoelastic segment when subjected to input motions that feature different frequencies and magnitudes, providing a comprehensive overview of the damper performance. Furthermore, the numerical simulation of the damper is provided at the component level. Finally, a steel portal frame is simulated as a case study to present the structural performance with the dampers under static pushover loads. The result of the study shows that the energy dissipation capacity of steel moment frames could be improved throughout the implementation of such devices.