Analysis Of Damping Performance Of Frame Structures With Weakly Layered Dampers

Because the reinforced concrete frame structure under the action of earthquake,it is possible to appear a layer of displacement Angle is relatively large,and the weak layer,when there is rare earthquake action,there is a great risk of leading to large layer deformation and collapse.In this case,viscous dampers placed in the weak layer of the structure can play a good role in damping,but viscous dampers in frame structures are generally arranged from the bottom to the top of the mid-span.To study whether the viscous dampers in the weak layer have higher damping rate than the dampers in the full layer,the dampers only in the weak layer can be considered.The responses of structures with viscous dampers only in weak layers and those with viscous dampers in full layers under frequent and rare earthquakes are compared and analyzed.(1)The formula of displacement amplification coefficient of viscous damper was derived by referring to various arrangement mechanisms of viscous damper;The layout diagram of diagonal layout mechanism is drawn and its geometric deformation is analyzed.Based on the theoretical analysis of viscous damper,the equivalent damping ratio formula of diagonally arranged mechanism with additional viscous damper is deduced,and the motion equation of the structure is established according to the calculation model of the structure.(2)Using the finite element software ABAQUS,an 8-story reinforced concrete frame model was established,and the weak layer of the structure was found by input different seismic waves under the action of frequent earthquakes.The viscous dampers are uniformly arranged in the full layer of the structure.By changing the parameters C and α of the damper,the influence of the changing parameters on the damping efficiency of the structure is analyzed.Finally,the values of C and α are determined based on the comparison results.(3)the formula derived from the use of the structure of the additional damping ratio,using ABAQUS software to continue for more than 8 layers framework structure of encounter and severe earthquake under the action of dynamic time history analysis,comparing with no control structure(model)and the structure of full layer with diagonal decorate the operation condition of the mechanism of 16 viscous damper(2)model and the structural weak layer with diagonal decorate the operation condition of the institutional arrangement of 12 viscous damper(three)model under the seismic action of interlayer displacement and interlaminar shear force and acceleration at the top.The comparison results show that the overall damping rate of Model 2 and Model 3 is significantly higher than that of Model 1,but the overall damping rate of Model 2 and Model 3 is less than 3.5%;Only at the weak layer,the damping rate of Model 3 is increased by 6% on average compared with Model 2,and the displacement increase phenomenon of interlayer displacement curve is changed at the weak layer.(4)in order to further improve the frame structure of viscous damper is decorated in weak layer after shock absorption rate,consider to decorate the efficiency high viscous damper,so choose the displacement magnification coefficient of bracing plan organization layout to the structure of the weak layer(4)model,continue with weak layer with diagonal decorate organization structure under severe earthquake action(model 3)dynamic time history analysis.The results show that the overall damping rate of model 4 is significantly higher than that of model 3.