عنوان مقاله [English]
Diagrids have received much attention in recent years as lateral-load resistant systems. Most of previous research works have modeled the structure on rigid foundations. It is while the present work takes into account the static soil-structure interaction in a planar 20-story example with a constant diagrid angle. A finite element program is provided for analyzing diagrid systems under a number of loading combinations including gravitational and lateral wind loadings. As the structural behavior depends on the distribution of section profiles among its members, sizing optimization is employed for screening the diagrid designs. Optimization is performed by a meta-heuristic algorithm inspired by hunting behavior of Falcons that samples the design space without need to any gradient calculation. The algorithm is recently developed in 2019 and applied for heat exchanger design. It simulates the hunting flight in: 1) logarithmic spiral flight in which the Falcon keeps its head straight looking sideways at the prey with maximum visual acuity, and 2) diving toward the prey by binocular vision. The first stage provides exploration while the second models search intensification in such a meta heuristic algorithm. In addition, the phenomena of klepto-parasitism between falcons is modeled to enhance the search. In order to apply both axial and flexural section properties in such a discrete problem, profile indices are taken as design variables. They are to be selected from the practical list of profiles during optimization. Member grouping is also employed to deserve symmetry and other practical considerations in the models. Consequently, diagrid design is fixed by minimizing the structural weight under code-based stress and deformation constraints. The designs are distinctly obtained for two cases of rigid and flexible soil-structure connections. By an external penalty approach, constraints are checked under simultaneous gravitational and wind loadings to be satisfied in the final optimal designs. Applying pushover analyses, various measures are studied and compared showing importance of soil-flexibility not only in the optimal costs but also in non-linear structural responses.