Optimal forms of two-pin arches

Abstract

A comprehensive review of the response of two-pin arches including catenary, parabolic and circular form to loading is presented. The effects of form on the arch structural response for static loading and span-toheight ratios (L:h) ranging from 2 to 8 are presented using finite element solution provided by the GSA software. Results have shown that circular arches represent least optimal shape, exhibiting high combined stresses and bending moments, particularly for the L:h ratio of 2 (semi-circular arch). The optimum L:h ratio for a circular rib arch is between 4 and 6, but the stresses that develop in it are still higher than in parabolic or catenary arches. This is with regard to the pure arch behavior for L:h≤5. The minimum of the combined compressive stresses in parabolic and catenary arches are observed at L:h ratio between 2 and 4. The parabolic arch demonstrated lower structural action effects when the uniformly distributed load (UDL) is greater than the self-weight (SW). Overall, the findings demonstrate that the response of 2-pin arch forms to applied loading is critically dependent on the arch form and its shape governed by the L:h ratio.