Instability design analysis in tied-arch bridges

A numerical investigation is proposed to identify instability strength of tied-arch bridges due to vertical loads, taking into account of a proper definition of the initial stress configuration and nonlinear geometrical effects involved in the bridge components. The main aim of the paper is to propose comparisons with data arising from existing codes by using a very detailed finite element model, emphasizing those scenarios in which current design methods overestimate the bridge instability capacity. Parametric analyses and new design methodologies are developed to identify instability strength and the influence of the bracing system on the bridge behavior.