| As a common structural system,frame structure has the advantages of flexible space arrangement,light weight and good economy,and is widely used in building structures.Due to the difference in the use of the building structure,some of the structures often need to set up equipment conversion layer with low floor heights,i.e."equipment mezzanine".The existence of the equipment layer often makes the structure vertically irregular,and the structure is prone to produce a weak layer,while the traditional "hard resistance" design method is difficult to ensure the performance requirements of the vertical irregular structure system under different levels of seismic action.Therefore,based on an engineering example of a vertical irregular concrete frame structure,Therefore,this paper is based on an engineering example of a vertical irregular concrete frame structure.The design method of energy dissipation and damping was adopted by attaching two types of energy dissipation and damping devices to the structure,namely viscous dampers and buckling restrained brace.and using the large finite element software ETABS to analyse the influence of the arrangement,location and installation quantity of the dampers on the damping effect of the vertical irregular structure.Finally,combining the advantages of the two dampers,a vertical irregular shock absorption scheme based on the layerby-layer arrangement method is proposed The main research contents and results are as follows:(1)Dynamic analysis of buckling restrained brace with different arrangement forms of the original structure shows that the buckling restrained brace improve the lateral stiffness of the structure,adjust the period and mode shape of the structure,and make the vertical irregularity of the structure tend to be regularized.The herringbone arrangement had the best shock absorption effect,and the interlayer displacement angle reduction rate was 53.3%～64.3% when earthquakes were common,and the interlayer displacement angle reduction rate was41.2%～53.4% when it was rare.Through the study of the ratio of buckling constraint support to structural lateral stiffness,it is found that the shock absorption performance of the structure is the best and most economical when the additional stiffness ratio is between 2.0～2.5.(2)The original structure was analysed using the conventional arrangement method,the power factor arrangement method and the layer-by-layer arrangement method for the viscous dampers respectively.The results show that the layer-by-layer arrangement method has a significant seismic reduction effect,and the utilisation efficiency and energy consumption rate of the dampers are high.The energy consumption rate is 57.2% in the case of multiple earthquakes and 48.8% in the case of rare earthquakes.(3)A hybrid damping scheme based on the layer-by-layer arrangement method is proposed.The analysis results show that: the hybrid damping scheme can improve the vertical irregularity of the structure while also providing good damping effect;the hybrid damping scheme has the highest energy dissipation rate when the number of flexural restraint braces and viscous dampers are arranged similarly;the static elastoplastic analysis of the hybrid damping scheme shows that: the hybrid damping scheme will improve the bottom shear bearing capacity of the structure by 16.2% at the performance point;comparing The maximum inter-storey displacement angle reduction rate is 35.58% when comparing the inter-storey displacement angles at the performance point;the study on the development of plastic hinge shows that the hybrid damping scheme can effectively inhibit the development of plastic hinge of the structure.(4)By comparing the performance indicators such as inter-storey displacement angle,floor shear force and energy dissipation between the two schemes with a single damper arrangement and the mixed arrangement damper scheme,it is found that the control effect of the mixed arrangement scheme is between the two single arrangement damper schemes,and the mixed arrangement scheme can reduce the number of dampers. |
