A static analysis-based method for estimating the maximum out-of-plane inelastic seismic response of steel arch bridges

This paper presents a method for estimating the maximum inelastic out-of-plane seismic response of upper-deck steel arch bridges. The method employs the equal-energy assumption to predict the maximum response without the need for dynamic response analysis. Firstly, applicability of the equal-energy assumption to upper-deck steel arch bridges is examined numerically by performing free vibration analysis, pushover analysis, and elastic and inelastic dynamic response analyses. Models with different arch-rise to span ratio and arch rib spacing are generated and the influence of these parameters on the applicability of the assumption is studied. Although the assumption resulted in conservative side estimation, in many cases the results were too conservative to be practical for design practice. On the other hand, some tendencies that make it possible to develop some correction functions to improve the estimation accuracy of the equal-energy assumption were found regardless of any parameters. Finally, by using the proposed correction functions and the response spectra a method that does not require dynamic response analysis for the estimation of maximum inelastic seismic demand is developed and its validity is evidenced by numerical analyses.