Control Of Earthquake Response Of Weak-Layer Structures Equipped With Energy-Dissipation Dampers

The stiffness of weak-layer frame structures is not uniform in vertical direction, and there will be severe layer-deformation in weak layer when earthquake occurs. To control the seismic response of weak-layer structures, the energy-dissipation dampers (EDD) equipped in weak layer are proposed in this paper. The EDD can decrease the seismic response of buildings by increasing the damping and dissipating the vibration energy of structure. The controlling devices, which move together with structures passively, produces the control-force of dampers, so this sort of passive controlling device which is simple, cheap, and stable, needs no extra energy. So more and more experts and engineering designers all over the world attach importance to it.Firstly, the dynamical performance of friction damper (FRD) and viscoelactic damper (VED) is tested in this paper. The work, which gets the rules that the two dampers' hysteretic curve and performance-parameters change follows the changing of excitement, lays the foundation for designing new kind of EDD. The FRD is designed as a new piston-type constant-friction-force damper, which dissipates energy efficiently and can be used in practical project expediently. According to the results of test, the dissipation mechanism of friction-viscoelastic damper (F-VED) is studied and its theoretical hysteretic curve is obtained.Secondly, the finite element models of the three dampers are constructed based upon the test, and the combined element stiffness matrix of damper-bracing system is deduced. According to the shear-type floor model of frame structure, a basic control equation is constructed to analyze the nonlinear seismic responses of structure equipped with EDD-bracing system. Subsequently the dynamical finite element analysis are carried on to obtain the seismic response of a twelve-floor R.C frame with the three EDD-bracing system under minute earthquake and disastrous earthquake, and the conclusions provide useful references for practical earthquake-resistant design.Finally, The vibrating table test and the relevant finite element analysis about steel frame model, whose weak layers are equipped with EDD-bracing system, are performed in this paper. The model added the three kinds of EDD-bracing system on the 1st, the 2nd and the top weak floor, experiences simulative minute earthquake and disastrous earthquake. The results of test and theoretical calculation indicate that the friction device does not slide under minute earthquake, thus the control effort of F-VED corresponds with VED, and the action of FRD is the same as pure brace. When disastrous earthquake occurs,the viscoelastic material reaches its shear limits and the friction device begins to slide, so the control effort of F-VED is the best.