Effect of Geometric and Loading Conditions on Stability of Prestressed Arches

Geometric and loading conditions affect stability and strength of arch frameworks. Prestressed arches that are made by buckling of flat struts into shape are more sensitive to these parameters. Most studies on prestressed arches are limited to the initial buckling path, not accounting for the looping response. This paper investigates the effect of arch rise-to-span ratio, support fixity, tapering of the arch section and various loading conditions on the complete response of prestressed arches. A corotational formulation augmented with a two-parameter path finding technique is developed to effectively trace the snap-through, snap-back, and looping paths of the arch. Results indicate that symmetric limit loads increase almost proportionally to the steepness ratio of the arch, whereas the asymmetric bifurcation loads asymptote around the rise-to-span ratio of 0.5. Clamped arches are more stable than their equivalent pinned arches, and do not demonstrate any looping behavior. A tapered-out prestressed arch with a taper angle of less than 2° 12′ is more stable than its equivalent prismatic or tapered-in arch. Prestressed arch is least stable when a point load acts within 12%–27% of its span length from the crown, or when only three-quarters of the span is loaded with a uniform load.