| Abstract: | Two linear optimal control laws and a non-linear control strategy are critically evaluated. They are implemented in a ten-story frame structure. For the linear control laws, both an active bracing system and a hybrid mass damper are considered as control devices, while the non-linear control law can be implemented with either an active or semi-active bracing system. The active and semi-active systems are compared to a passive bracing system with linear viscous dampers and to a hybrid system consisting of a passive bracing and a hybrid mass damper. Dimensionless indices based on the reduction of the maximum story drift and on the maximum control force required are introduced to compare the efficiencies of different control strategies. While the linear optimal control laws exhibit an excellent performance, the non-linear control law, in addition to its simplicity and robustness, appears to be more efficient when the allowable control force is within a certain limit. Furthermore, one attractive feature of the latter is that it can be implemented with semi-active devices to minimize the power requirement. |
