Optimal circular arch shapes under multiple load conditions (1st International Conference on Optimization Driven Architectural Design Jordan, November 5th - 7th, 2019)

Arch shape is one of the oldest used in architecture and structural engineering, but thanks to its efficiency it is still frequently used, specially, for long span bridges. The shape of an arch is reached at the conceptual design stage, usually resulting in one of three idealized configurations: circular, parabolic or catenary. These forms become bending-less arches under certain fixed load conditions. Although the real structural elements are subjected to a huge number of possible load combinations, there is an only one “bending-less” configuration that is possible, while the safety evaluation must be conducted for each possible load configurations, that means considering static coupling effects of bending and shear actioning on each arch sections. In this paper is evaluated an optimal configuration of a circular arch, subjected to different vertical load combinations, evaluating the height to span ratio, the cross section (hypothesized constant along the arch) and the inertia modulus, as the main representative parameters to be considered. The analysis is performed with the aim to evaluate the optimal configuration able to minimize the self-weight of the arch, not only to limit the materials but also to find solutions for the constructive stages. The analysis is performed using a numerical solution of circular arches equations neglecting shear and axial deformations and considering a homogeneous material. The objective function considered is the total arch weight, while the load is applied in symmetrical and antisymmetrical configurations