ABSTRACT
This chapter attempts to shed some light as to how arches can be designed from first principles, before relying on full computational solutions. Arches take two forms: parabolic or circular. Parabolic are the most common because they do not develop moments when subjected to uniformly distributed loads. Arches used for buildings are often restrained against out-of-plane buckling by the roof; however, arches used for bridges often have less restraint. The only load combination is dead load over the full span and imposed load over the half span. This provides adverse conditions because the moments induced by the imposed load unbalance the arch, inducing sideways sway, which in turn promotes buckling. The design method presented explains how to calculate the elastic critical buckling force for parabolic arches using the basic Gordon-Rankine approximation to convert the elastic critical and crushing forces into a design value of buckling strength.
