Selective combined control stiffness and magnetorheological damping system in nonlinear multistorey structures

The application of a combined controlled stiffness and magnetorheological (MR) damping system in a base-isolated nonlinear multistorey structure with amplifying braces is described. Passive control theory is used to obtain the viscous characteristics of the MR damper fluid. Selective control of the proposed system is used to enhance the behaviour of a structure during earthquake. The nonlinear equations of motion are solved using the Wilson θ method. The control forces are obtained using instantaneous control theory with the predictive control approach. The efficiency of the proposed system is demonstrated by a numerical simulation of a seven-storey building subjected to four different earthquake. The stimulation shows that the behaviour of the selective controlled structure with the proposed damping system is significantly improved compared to that of an uncontrolled structure. The energy required for the adjustment of the proposed system with amplifying braces is much lower compared to that of the case of MR dampers connected directly to chevron braces. The response of the predictive controlled structure is close to that of an instantaneous controlled structure.