| Structural energy dissipation damping technology is a kind of passive control of structures.It is an effective way to install friction dampers in key parts of structures.Friction dampers generally act together with braces to form the friction-damped braced frame.As a kind of energy dissipation shock absorber,friction damper has simple structure,strong energy dissipation capacity and can be replaced according to different building functions.Due to the variable form of the rotational friction damper,the complicated technical parameters,and the late start of domestic research,the research is not deep enough and it is difficult to be extended to practical projects.In this paper,based on the experiments of rotational friction damper carried out by the research group,the seismic performance of steel frames with rotational friction damper is analyzed.The research contents are as follows:(1)The principle of energy dissipation damping technology and friction damper was introduced,and the theoretical analysis,numerical simulation and experimental research on rotational friction damper by domestic and foreign scholars were summarized.(2)The multi-scale model and solid element model of the steel frame structure with rotational friction dampers were established using ABAQUS finite element software,and the effectiveness of the multi-scale model in pseudo-static and pseudo-dynamic analysis was verified.Based on the multi-scale model,the energy dissipation performance of steel frame structure under different parameters of high-strength bolt pre-tightening force of rotational friction damper was studied.Set the pre-tightening force of the high-strength bolts to 0.5P,0.65 P,0.8P,P,and repeated displacement loading was carried out on the structure,and the following conclusions were obtained:(1)The column foot and the end of beam yield first.The stress of the rotational friction damper is mainly distributed in the contact part between the steel plate and the friction plate,The stress diffuses along the steel plate and increases with the increase of the high-strength bolt pre-tightening force.(2)The hysteresis curve of each structure show a relatively full parallelogram without obvious pinching.And the stiffness of the steel frame with the rotational friction damper is greater than that of the ordinary steel frame structure,indicating that the rotational friction damper can provide additional stiffness to the structure.Compared with the ordinary steel frame structure,the bearing capacity of the structure with the rotational friction damper is increased by25% to 39%.When the inter-layer displacement angle of 3% is applied,the energy consumption capacity is greatly improved,in the range of 30%-89%;(3)The energy dissipation coefficient and equivalent viscous damping coefficient increase with the increase of the high-strength bolt pre-tightening force,indicating that the higher the high-strength bolt pre-tightening force,the stronger the energy dissipation capacity of the structure,but the energy dissipation coefficient of GKJ-0.8P and GKJ-P is close,and the equivalent viscous damping coefficient is the same.Therefore,when the pre-tightening force of the high-strength bolt increases to a certain extent,the energy dissipation effect of the friction damper increases very little.(3)The stress development,inter-layer displacement angle change,and energy consumption of a 4-story steel frame structure with rotational friction dampers under the action of EI Centro wave,Taft wave and Lanzhou wave were studied,and the following conclusions are obtained:(1)At the beginning,the first layer of support yields first.When the high-strength bolt pre-tightening force is 0.65 P and 0.8P,the rotational friction dampers of each layer participate in energy consumption,but when it is p,only the first layer of the rotational friction damper works obviously.Therefore,the pre-tightening force of the high-strength bolts should not be too large,and it is necessary to ensure that the rotational friction damper can slide under the action of a large earthquake,and play an energy dissipation effect;(2)The displacement angle of the first or second floors of the steel frame structure exceeding the specification limit,when the rotational friction damper is installed,the inter-layer displacement angle of each structure is less than 1/50.When the pre-tightening force of the high-strength bolt is 0.65 P and 0.8P,the inter-layer displacement angle of the overall structure is reduced,and the inter-layer displacement angle of each layer of SGKJ-0.8P is the smallest;(3)The energy consumption of the friction damper is in the range of 22%-40%.When the high-strength bolt pre-tightening force is 0.8P,the friction damper consumes the most energy;when it is 0.65 P,the friction damper consumes less energy.When it is 0.5P and P,the energy consumed by the friction damper accounts for the same proportion of the total energy consumed by the structure,so the high-strength bolt pre-tightening force should not be too large or too small.(4)11 finite element calculation models were established using SAP2000,modal analysis and elasto-plastic time history analysis under the action of 8 degree rare earthquakes were carried out for the five layout forms of rotational friction dampers.The inter-story displacement,apex displacement,apex acceleration,and the shear force of column bottom were studied,and the time history curve and damping rates were compared and analyzed.The following conclusions were obtained:(1)The order of natural vibration period of the steel frame model with a rotational friction damper is GKJ-ZN4<GKJ-ZN3<GKJ-ZN2<GKJ-ZN5<GKJ-ZN1(GKJ-ZN1～GKJ-ZN5 are arranged with dampers at the bottom of 1/4 building height,1/2 building height,3/4building height,full and interlayer respectively).This shows that the rotational friction damper in the model GKJ-ZN4 provides the largest additional stiffness for the structure,followed by GKJ-ZN3;(2)Under the action of an 8 degree rare earthquake,the inter-story displacement of the model with rotational friction damper is significantly reduced,but the maximum acceleration at the apex tends to magnify,indicating that the rotational friction damper has better control effect on displacement than on acceleration;(3)Compared with other models,the stiffness and seismic capacity of GKJ-ZN3 with the rotational friction damper installed at the height of 3/4 of the bottom layer have been significantly improved.And the rotational friction damper can slow down the plastic deformation and the development of plastic hinges of steel frame structural members. |
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