Optimum design of an arched truss under vertical and horizontal multi-load cases

Simultaneous topology, shape (form-finding) and size optimization of steel arched trusses was performed under vertical multi-loading case and seismic action. To bear vertical multi-loading cases, optimum truss arches were optimized by shaping the two chords in order to suitably convert bending moments acting along the truss arch into axial forces in each arched chord, thus allowing to bear highly different multi-loading cases. The chord shape is identified by defining the form of the arched chords through Cubic Rational Bézier curves. Similarly, when considering the seismic action too, two arched chords are still considered, but lying on different planes. For this purpose, the upper chord of the truss arch has been supposed to lie on the horizontal plane, while the lower chord was shaped as an inclined arch. The two arches are connected by a bracing system, thus collaborating to bear the external loading. The horizontal arch primarily resists to the earthquake action that mainly determines its shape, while the vertical loads are transferred to the inclined arch, thus mainly affecting its shape