Design And Analysis Of United Energy Dissipation Steel Frame With Viscous Dampers And Buckling Restrained Braces

Up to now, research on structural vibration control is still mostly focused on the structure of using one single type of damper. If using velocity-type damper in structural vibration, only by increasing the stiffness or additional damping of the main structure can better deformation controlling is acquired. But this means the amount of material or dampers will increase. If using displacement-type damper in structural vibration, only by increasing the tonnage or number of the dampers or improving the main structural stiffness can better deformation controlling is acquired. But the increase of earthquake force demands more material. The increase of damping force not only means higher requirement of the connections and nodes is demanded, but also means additional force to main structure is larger. These problems tend to be more prominent in high seismic intensity areas. And deformation controlling effect of velocity-type damper is not as significant as displacement-type damper. But its effect of reducing the earthquake force was superior than displacement-type damper. And its damper force is zero when structural deformation is the maximum. So the performance of both is exactly complementary. Therefore, the united energy dissipation method of using velocity-type damper and displacement-type damper was proposed in this paper. And study on united energy dissipation structure of steel frame with viscous dampers and buckling restrained braces was conducted. The main contents and results are presented as follows:Firstly, matching between the two types of dampers and main structure was researched. And a united energy dissipation design method of steel frame was put forward. Considering 4 kinds of height and 3 kinds of lateral stiffness,12 pure steel frames were designed. To each pure steel frame,11 values were assigned to the normal lateral stiffness ratio k of buckling restrained braces. When assigning one value to k and setting up all buckling restrained braces, the structural deformation was damped to forecast deformation. And the corresponding additional damping ratio must be calculated and distributed to every floor. Then the parameters of viscous dampers were calculated according to distributional additional damping ratio of every floor and all viscous dampers were set up.132 (12 groups) united energy dissipation structures of steel frames were established according to this method. Then relation curves of the maximum story displacement angle changed with k were established through elastic-plastic time history analysis of these models. Then, propositional matching values between the two types of dampers and the pure steel frame were given. And a method based on spectrum under the frequent earthquake was proposed under the consideration of aforementioned matching.Secondly, a united energy dissipation structure of steel frame was designed according to the proposed propositional matching values and design method. Its energy dissipation effect was also analyzed. Study showed the presented propositional matching values were effective. And process of the corresponding design method of united energy dissipation was succinct and easily operated.Thirdly, pure buckling restrained braces energy dissipation of steel frame was designed. And the comparative analysis of energy dissipation effect with the united energy dissipation structure of steel frames was conducted. Study results showed that the pure buckling restrained braces structure required being added lots of braces. Structural stiffness increased apparently. So its displacement controlling effect was slightly better than united energy dissipation structure. But its earthquake force increased greatly than the latter. And its storey acceleration is greatly larger than the united energy dissipation structure. Damping force of the braces in pure buckling restrained braces structure was nearly twice of the united energy dissipation structure. So the higher requirement of the connections and nodes was demanded in pure buckling restrained braces structure. Energy dissipation capacity and ductility of braces in pure buckling restrained braces structure was exerted slightly. But the energy dissipation capacity and ductility of the two types of dampers in united energy dissipation structure were both exerted commendably.In summary, this paper proposed the method of united energy dissipation. And the analysis on the united energy dissipation steel frame with viscous dampers and buckling restrained braces was conducted. The corresponding propositional matching values were given. And one corresponding design method was proposed. It provides reference to structural energy dissipation design to some extent.