Optimal arches shape for single-point-supported deck bridges

The arch shape is a timeless structural solution as it has been widely used in the past but is still a common solution adopted nowadays for large spans. Structural efficiency depends primarily on optimal material exploitation, which allows us to minimize the structural volume. The paper is framed in the context of optimization of arch structures, and analytical design criteria are proposed, dealing with a specific class of deck bridges supported in the mid-span by arches. The investigation deals with a simplified structural scheme, constituted by statically determinate plane arches under self-weight and a single vertical load in the key section, exerted by the deck supports. The optimization criterion assumes a constant normal stress in all arch sections and the resulting arch shape is computed in closed form. Finally, the existence condition for the proposed solution is provided and some numerical examples are introduced.