The present paper discusses a method for estimating the yield seismic intensity of arch structures based on the continuum arch theory. First, the modal parameters, which are natural periods and dynamic eigen modes, are estimated based on the continuum arch theory. The equivalent static seismic load is evaluated by the estimated modal parameters. The maximum responses obtained by the time history response analysis are compared with the maximum responses obtained by the proposed seismic force, and the validity of the proposed seismic load is investigated. Second, the buckling behavior and initial yield seismic intensity are investigated based on elastoplastic analysis using the equivalent static seismic loads. Finally, a method for estimating initial yield seismic intensity based on continuum theory without FEM analysis is proposed and the validity is discussed.
