Mutual effect of geometric modifications and diagrid structure on structural optimization of tall buildings

Abstract

Structural efficiency and flexibility in architectural planning have made diagrid structural system so popular among engineers and architects, currently. Since considering architectural and structural parameters can help architects and engineers to have more efficient buildings the focus of this research is to study the effect of both different geometric base and top plans configurations of tall building and the angle of diagrid structure to design efficient tall buildings with respect to two objectives: the total weight of structural elements per unit area and horizontal displacement of top floor (both minimized). To this aim, 64 parametric models with various cross-sectional shapes and 180 m height are generated by randomly increasing the number of sides at the base and top plans. The generated models are developed for varying angle of diagonal members. Rhino software and its plug-in Grasshopper are used for modelling and Grasshopper's plug-in called Karamba is used for structural analysis. The optimal models are resulted by means of genetic algorithm-based optimization. Ultimately, it is found that the optimum bound for diagrid angle is between 53° and 70° and if the number of polygonal cross-sections goes up, the efficiency of the buildings with diagrids that have the optimum diagonal angles increases.