An Experimental Study on Semi-active Seismic Response Control of a Large-span Building on Top of Ship Lift Towers

Abstract

A vertical ship lift under earthquake excitation may suffer from a violent whipping effect due to the sudden change of building lateral stiffness at the top of ship lift towers. This paper presents an experimental investigation to explore the validity of using a magnetorheological (MR) isolation system to prevent the whipping effect manipulated by neuro-fuzzy control algorithm. The two-story building was constructed as a ship lift model, in which the first story was much stiffer than the second story and the plates of the second story were divided into two mass pieces. MR isolation systems were used to link those two mass pieces. The dynamic characteristics of the model with rigid connection and with only seismic isolator connection were first identified. The models with those two connections and with MR isolation system connection were then tested under the scaled Three Gorge artificial ground motion and the scaled El Centro 1940 north-south ground motion. Finally, the seismic responses of the ship lift model were recalculated with the modified structural parameters through measured natural frequencies and were compared with the experimental seismic responses. The experimental results show that an MR isolation system manipulated by neuro-fuzzy control algorithm can achieve a significant reduction in seismic whipping effect on the building model. The comparison consequences indicate that the theoretical simulation results are accurately consistent with the experimental results.

Keywords

Ship lift tower building models MR damper vibration control Whipping effect isolation.

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