Analysis Of Lateral Collapse-resistance Of Steel Frame Based On Beam-to-column Connections And Buckling Restrained Brace

In the past earthquakes,the beam-to-column connections of steel frame are the areas that are more vulnerable to damage lead the structure collapse.Therefore,in order to avoid the brittle damage of the beam-column connections,more and more scholars conduct the nodes and components that can participate in energy dissipation during the earthquake by extensive research.However,the existing requirements of building design codes in China fulfill the premise of safe using of nodes by the bearing capacity of nodes and components,but often do not consider the safety of the overall structure.Based on the overall performance of the structure,this paper considers the application of energy-dissipated connections and buckling restrained brace on steel frames and analyzes the lateral collapse-resistance of different combined energy-dissipated structures and gives relevant applications of scope and design recommendations.This paper adopts multi-scale modeling method by ABAQUS and apply the energy-dissipated connections and buckling restrained brace of seismic designing to the steel frame,focusing on seismic analysis and lateral collapse analysis of different combined energy-dissipated structures.The seismic performance of different composited energy-consuming steel frames is compared in the frequent and rare earthquakes.The interlayer displacement angle,vertex displacement and base shear force are used as indicators to analyze the impact of earthquake-resistance capability by the energy-dissipated connections and buckling restrained brace support structures under small earthquakes and large earthquakes.Based on the incremental dynamic analysis(IDA),different combined energy-dissipated steel frames were analyzed and aggregated into multiple IDA curves.Qualitative and quantitative analysis based on collapse vulnerability,collapse margin ratio(CMR)and collapse risk values.The lateral collapse-resistance of steel frames under differe nt combined energy consumptions,and through the different combinations of energy-dissipated connections and buckling restrained brace support,a total of 24 steel frame models with different layers and different spans are designed.IDA analysis,to evaluate the impact of the number of layers and the number of spans on the collapse resistance of the structure,the conclusions can provide a reference for the relevant design.The conclusion shows that the energy-dissipated connections can effectively improve the collapse-resistance of the structure,and the buckling restrained brace can greatly reduce the risk of structural collapse,but the application scope of them is not the same.(1)Within the scope of structural safety requirements,for buildings with lower structural safety requirements,energy-dissipated connections can be used to improve the seismic performance of the structure to reduce the risk of building collaps ing.The web weakened connection is suitable for buildings with higher ductility requirements.For buildings with higher requirements on the ultimate bearing capacity of the structure,flange-reinforced connection can be applied for buildings with higher structural safety levels,the application of energy-dissipated can greatly reduce the risk of collapse in the structure.(2)In the scope of application of connections and components,the energy-dissipated connections are more suitable for buildings with medium and low-rise layers and excessive number of buildings.In high-rise buildings,the application of energy-dissipated support can greatly improve the lateral collapse-resistance of the structure,and the energy-dissipated connections and the buckling restrained brace combination energy consumption form are the optimal arrangement.At the design of energy-dissipated connections and buckling restrained brace,it should be noted that the flange-reinforced combination should follow the principle of “strong columns and weak beams”.When the beam-to-column connection area is strengthened,the column cross-sectional area should be appropriately increased to ensure the ductility of the overall structure performance;the scale of the web weakening is moderate,ensuring that the bearing capacity of the beam section meets the design requirements,and does not weaken too much and affects the collapse of the structure;the buckling restrained brace should be designed and used under the premise not affecting the use function of the building and not causing excessive steel waste.In the middle and high-rise building design process,on the one hand,it is necessary to reasonably control the overall stiffness of the structure,optimize the size of the beam-column connection,and on the other hand,reducing the risk of collapsing in the structure by arranging the energy consumption form of the energy-dissipated connections and the buckling restrained brace.