Seismic Deflection Response of Vibration Control Structures and the Optical Fiber Sensing

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Recently, many structural passive control systems have been demonstrated to reduce the response during an earthquake and have gradually been applied to buildings. The authors developed new passive control system using a non-structural flexural yielding beam and the system was recently applied to the six-story office building. The present concept of this control system consists of two kinds of non-structural steel members the one is a brace and the other is of horizontal members, the short span beam. During sway motions the bending strains in this non-structural flexural yielding beam are bigger than those in the structural members. Therefore, this non-structural flexural yielding beam yields earlier than the structural girders or columns and acts as damper absorbing vibration energy by its hysteretic performance. In our previous papers the basic dynamic responses of the test models on a shaking table under sine and random wave motions were demonstrated experimentally and in parallel th … More e earthquake responses of the steel buildings with this system were analyzed This system needs limited special devices and has little influence on the architectural planning. Also as optical fiber Bragg grating sensors were installed on the non-structural flexural yielding beams, the damage level of this system has been assessed even after any earthquake.For practical design it had been necessary to confirm the various details associated with the installation of this system using large scaled specimens. This study deals with the large-sale steel frame specimens tested under static cyclic loading. Shown in this paper are that the experimental results and the idealized theoretical model are consistent The effects of the rigidity, strength and size of the non-structural flexural yielding beam (damper beam) on the equivalent damping factor as a damper as well as on the elastic-plastic hysteretic absorption energy were discussed. The effects of the shape and size of the bending failure beam as a damper on the elastic-plastic hysteretic performance have also been discussed. The optical fiber Bragg grating sensors have been installed on the surface of the beam and the optical power spectra as well as the strain quantities using their outputs have successfully been measured in detail. It has been shown that the spectra change from sharp one-peak type to multi-peak one due to steel yielding. The characteristics would be useful for assessing the damage level after large earthquake. Less