Seismic response of full-scale structure with added viscoelastic dampers

This paper presents the test and analytical results of a full-scale 5 story steel frame with added viscoelastic (VE) dampers. The ISD110 VE dampers made by 3M Company are installed to the long (East-West) direction of the structure. In addition to carrying out ambient and free vibration tests, the dynamic responses of the VE structure under four moderate earthquakes are recorded and analyzed. The ambient vibration tests show that the increase of damping in the full-scale structure is not obvious because of the small input energy. Nevertheless, in the free vibration tests and under earthquake ground motions, the increase of damping ratio is very significant. Analytical results show that when the structure is added with the diagonal-damper-brace assemblies, the modal strain energy method that has been validated by extensive shaking table tests on small-scale models slightly overestimates the damping ratio of the full-scale structure. However, when the structure is added with the floor-damper-brace assemblies, the method slightly underestimates the damping ratio. In addition to providing important database for verifying the effectiveness of applying the VE dampers to full-scale structures, this study also obtains important experiences concerning the implementation and detailed design of damper connections for practical applications.