The Effect Analysis Of Near Fault Groud Motions On Fragility Of Mild Steel Buckling Restrained Brace Frame Structrue

In the most current analysis for energy dissipation structure, only a nonlinear model are established for energy dissipation device, and the linear elastic model are established for strengthened structure. This cannot be considered in the analysis model under the influence of severe earthquake, the old structure may still suffer from earthquake damage. Therefore, according to a mild steel buckling restrained brace (BRB) structure project, this paper establish nonlinear model for both structure and energy dissipation components in order to reflect the nonlinear dynamic response of reinforced structure truly. At the same time, the existing research indicates that nonlinear dynamic response of reinforced concrete structure have obvious differences between near and far field earthquake records. The design of energy dissipation make the nonlinear dynamic characteristics of reinforced concrete structure become more complex. In order to understand the BRB characteristics in nonlinear dynamic response of reinforced structures between the near and far field earthquake, this paper makes a further research on the following based on the IDA:①This paper introduces BRB reinforcement structure, energy dissipation, stiffness enhancement principle and basic characteristics of buckling restrained brace structure system.②This paper chooses a reinforced concrete frame structure of the old warehouse as an example, determine the buckling restrained brace of steel core, structure parameter and the axial stiffness by the standard calculating process of Japanese isolation structure association.③This paper stablished the nonlinear analysis model of reinforced concrete based on beam elements for the old structure, Using the nonlinear finite element analysis program Zues-NL. And a mild steel damper model is stablished By means of nonlinear link element. It formed the complete nonlinear analysis model of structure reinforced by BRB.④In this paper, it took IDA dynamic analysis on reinforced structure based on the near, far field earthquake records provided by ATC-63. And the results according to the the difference of IDA curves and statistical results figure reflect Influence of BRB reinforced structure’s vulnerability based on the Spectral characteristics of near, far field ground motion records.The analysis results of the above research can provide reference and basis for both the components design of actual BRB reinforced engineering and Seismic risk analysis.