Seismic Response of and Design Aids for Arch Bridges

Abstract

Design aids for estimating the seismic effects on deck type of arch bridges are presented. They are based on the in-plane response of a linearized model. For the model, the structural tangent stiffness at the end of a nonlinear analysis for the dead-load response is used as the linear stiffness in the subsequent linear seismic response calculations. Comparisons with results produced by using a nonlinear analysis throughout the ground motion indicated very close agreement. The design aids are based on the American Association of State Highway Transportation Officials response spectrum. Time-history solutions were also obtained for parabolic ribs using three earthquakes. Their averages are found to be similar to the response spectrum results. The design aids give, for every eighth panel point, stress amplification factors from which the seismic (plus dead load) stress may be obtained, and maximum vertical and horizontal displacements. The presented data should cover most practical ranges of the parameters defining arch bridges with parabolic and circular ribs, with hinged or fixed supports.