DAMAGE PREDICTION OF 17-STOREY STEEL FRAME UNDER NORTHRIDGE EARTHQUAKE

In order to further study the effect of cumulative damage and degradation on seismic behaviours of steel frames and apply the equivalent constitutive model to actual project, a damaged 17-storey steel frame by Northridge earthquake was selected. Time history analyses of both equivalent constitutive model considering damage and lumped plastic hinge model without considering damage were carried out. Structural deformation, failure modes and damage positions were predicted. The differences in seismic responses calculated by the two models were compared. The analysis results show that: Equivalent constitutive model can more accurately predict the deformation and failure of steel frames under seismic excitations, which were more consistent with actual observations. The model improved the traditional beam element model and enhanced computational accuracy. Due to the damage of members and connections, the actual deformations of steel structures subjected to rare earthquake were obviously larger than the calculated results without considering damage. If this effect was not considered, the design would be unsafe.