Lifetime performance assessment of ductile steel frame using fractional model of viscoelastic dampers considering uncertainty parameters

Abstract

Viscoelastic (VE) dampers are powerful tools for mitigating structural response when exposed to an earthquake. The fractional models for these dampers are adequately capable of taking the effects of ambient temperature and excitation frequencies into account. In this paper, the effect of these dampers on reducing the life-cycle cost of steel structures and the exceedance probability of different damage states is evaluated during the lifetime of the structures. Modal pushover analysis has been employed for nonlinear dynamic analysis of the steel frames with viscoelastic dampers. The effect of the random parameters, such as ambient temperature, excitation frequency, and accelerogram type, were also considered. The results from the analysis of six presented scenarios demonstrate a significant improvement in structural performance, especially in reducing the maximum inter-story drifts and ductility demands. Incorporating VE dampers into different design scenarios has decreased the expected damage cost and total life-cycle cost of the structure by at least 58% and 31%, respectively. Also, it was observed that due to the nonlinearity of the equations and uncertainties associated with seismic loading and ambient temperature, the best design scenario is not easily predictable.

Keywords:

• Viscoelastic dampers
• nonlinear dynamic analysis
• fractional models
• life-cycle cost analysis
• seismic performance assessment