Seismic control with tensioned cables for suspended ceilings

Ceiling collapse has been continuously reported all over the world in the case of earthquakes in particular. Compared with the damage to structural members, ceiling collapse is likely to occur on the lower seismic scale. Therefore, the prevention of ceiling collapse is urgently necessary, especially in cases where it is suspended, and is the most important matter as it is regarding life safety. Further steps could also be taken to consider business continuity and to preserve space functionality in case of disaster, as well as integrating many kinds of failure control, such as seismic reinforcement of the ceiling. However, seismic reinforcement for the back-up frames of the existing ceilings is usually very difficult. In this paper a new type of vibration control of the ceiling is proposed. The method uses parabolic arrangement of reinforcing cables and allows access from the surface below for easier installation. The seismic retrofit of an existing suspended ceiling with such method was examined as an example. Static tests, free-vibration tests and shaker tests were performed to confirm the validation of this new seismic retrofit system with an existing suspended ceiling of size 6 x 10 m before and after the reinforcement. As a result of these experiments, with the increase in the initial tension of the cables, the increase of the horizontal stiffness and the decrease of the ceiling response displacement were confirmed.