Analysis And Design Of Vibration Control Against Earthquake For Structures

The research and application about vibration control in civil engineering were considered as a great progress for structures under earthquake and strong wind excita -tion, traditional seismic design, changing architectural characteristic itself, had been developed into other useful methods to suppress earthquake and wind responses, such as the active or passive control systems. Mass Dampers, such as Tuned Mass Damper and Active Mass Damper, were the most common systems in all of control systems. Comparing to active brace systems or semi-active stiffness systems, they were simpler in design and maintainability, especially for existent buildings. Under the engineering background of a high-rise steel construction, the analysis and design of employing Hybrid Mass Damper against earthquake excitation for this building were carried out.First, by the analysis of structural control mechanism with active or passive mass damper, the formula for optimal parameters was obtained as a result. Using the three common active control algorithms, control strategies in time domain were designed, in addition, there different gain matrixes Q and R were got too. Afterwards, some Matlab programs for the structure with control system against earthquakes were composed, and the numerical simulation for the structure with TMD/MTMD/HMD were carried out. The simulation results showed that active or passive mass damper could also play good roles on suppressing earthquake responses of such a building, but HMD is better in validity and robustness.At last, using LQR, optimal control forces by actuators were designed, character -ristics of active control forces themselves were researched, the influences by active control forces for structure were analyzed, time-lag actions for control systems were solved. The simulation results showed that the active control system changed the structural stiffness and damp in fact, and also gave support to the structure with semi-active control system in theories.In this paper, two innovative thinking in high-rise construction with active control system against earthquakes are as follows:(1) Three different active control strategies were designed for each control algorithms, three different gain matrixes Q and R were got. The controllers can effectively eliminate earthquake responses of such a building, and the corresponding results can be used as reference for similar control problems of other high-rise building structures.(2) Using evaluation criteria of a benchmark seismically excited building, the effect of HMD was obtained; under two different criteria, direction and magnitude of active optimal control forces were measured, the relations between control forces and displacements and velocities in each floor were found, the conclusion that elastic force in active optimal control force was dominant was found too. Those results were meaning for practical engineering.