Shaking table tests of magnetorheological damped frame to mitigate the response under real-time online control

Magnetorheological (MR) dampers are increasingly employed to attenuate the harmful vibration in Civil Structures caused by dynamic loadings such as earthquakes and strong winds for their excellent response mitigation capacity. The credibility and precision of dynamic response mitigation capacity of MR dampers are highly dependent on intelligent control strategy. In this paper, a piecewise control algorithm based on the feedbacks of story drift and ground excitation acceleration is adopted through a micro-controller with a digital signal processor chip as the control processor. Shaking table tests are carried out on a three-story steel frame structure which incorporates MR damper with the micro-controller installed between the ground and first floor. The dynamic responses of the real-time online intelligent controlled structure are compared with those of passive-on and passive-off controlled structures under different earthquake waves to evaluate vibration control efficacy of the MR intelligent control system. Test results show that the developed MR intelligent control system can sufficiently reduce the peak and root mean square responses due to earthquake excitations, and the control efficiency of displacement and acceleration responses is higher than the two passive control cases.