Investigation of the effect of plan geometry and curvature of the building body on the seismic behavior of tall buildings by using hexagrid structure

The geometric shape of the building, both in plan and in height, influences seismic behavior. Furthermore, the form of the building is very important in terms of aesthetic issues and the function of the building in architecture. so, if the form of the building can be designed in such a way that not only responds to the architectural features of the building, but also performs better in terms of structure (seismic behavior), it will be possible to achieve these two goals simultaneously. Also, less attention has been given to the geometry and plan capabilities of the building for seismic stability. Therefore, in this article, in addition to considering architectural constraints such as the area of the central core and floors, building height, free plan and appropriate light depth in the floors, by making changes in the shape of the building body in height and plan, to compare its seismic behavior. Furthermore, by creating appropriate forms, which could achieve the needs of architecture and building structures and make the design economical. For this purpose, 70-storey hexagrid buildings structure with three shapes of circle, pentagon and triangle in plan and three different forms in in height cylindrical forms, convex and concave, with the same total area, have been studied. The research is quantitative and the modeling of forms has been done by the Rhino software through the analysis of structural models in the SAP 2000 software. Based on the obtained results, it can be stated that, by reducing the number of sides of the plan in convex sections, the total weight is reduced by 11.4% and the base shear is reduced by 10%, while with increasing the number of sides of the plan in concave sections, the total weight is reduced by 5% and the amount of base shear There is no significant difference with increasing or decreasing the number of sides of the plan