In this paper, we introduce shaking table test of a full-scale two-story structure with story deflection control system. The story deflection control system is a Linked Fluid Inertia Mass Damper we developed in the previous study. The purpose of the shaking table test is to verify that the seismic response control by Linked Fluid Inertia Mass Damper (LFIMD) works quite effectively for the real scale structure. The test frame is a light-gauge cold-formed steel frame consisting of walls with built in friction devices and CLT floor panels. The story height is the same as of actual structure. Walls in the shaking direction are equipped with friction devices. In addition, normal structural plywood shear walls are installed in the frame orthogonal to shaking direction to minimize deflection in that direction. We call this structure a basic frame. In this shaking table test, we compare the test results of basic frame and those of the frame with LFIMD.
First, we study dynamic characteristics with/without the damper. Second vibration mode does not clearly appear and first vibration mode damping ratio increases by using the damper. The test results of basic frame show that the damage is likely to concentrate to 1st story. The tendency becomes more prominent as the yield strength ratio of the first story becomes smaller. On the other hand, the story deflection distribution will be quite uniform by using the damper. Important thing to note is that response acceleration may increase, but the maximum value is suppressed to no greater than 10 m/s2.
Next, we constructed an analytical model of the test frame to quantitatively evaluate the seismic response control effect by LFIMD. The friction device installed in shear wall of the main structure was simulated by tri-linear type load-deflection relation. Its validity was confirmed by incremental displacement analysis. And the mechanical properties of the damper were identified by comparing test results with those theoretically calculated results. Although viscous damping effect and inertia mass effect was the same as we had expected, link stiffness showed lower stiffness than that obtained in the pre-performance test. Time history response analysis showed that the dynamic analytical model using modified link stiffness can simulate the test results fairly well. We studied the seismic response control effect of installing LFIMD by using this model. Analytical results showed that viscous damping effect is effective in reducing response story deflection. Inertia mass effect is effective in reducing response acceleration. Link system is effective in preventing damage concentration. From the results above, it was clarified that Linked Fluid Inertia Mass Damper can exert high seismic response control effect by comprehensively exhibiting each seismic response control effect.