Proposing the hexagrid system as a new structural system for tall buildings

Abstract

SUMMARY In order to improve the efficiency of tube‐type structures in tall buildings, a new structural system, called hexagrid, is introduced in this paper. In comparison with diagrid system, it consists of multiple hexagonal grids on the face of the building. In this research, a set of structures using diagrid system having four various diagonal angles and hexagrid system were designed on a strength and stiffness‐based approach for buildings with 30, 50, 70 and 90 stories to withstand wind load. The impact of different geometric configurations of structural members on the maximum lateral displacement and architectural performance in both diagrid and hexagrid systems is compared. The stiffness sensitivity using a similar interior bracing system in both systems is also discussed. In this study, the seismic performance of a 30‐story diagrid structure and a hexagrid structure was evaluated using nonlinear static and dynamic analyses. According to the results, the hexagrid system has a better architectural view and more ductility and stiffness sensitivity, which are about three times than that of the diagrid system. And finally, in comparison with the diagrid system, the hexagrid system has enough potential to push the height limit. The guidelines discussed here are for architectural and structural engineers to improve freehand design. Copyright © 2012 John Wiley & Sons, Ltd.

Diagrid: An innovative, sustainable, and efficient structural system

“…They have a larger lateral stiffness compared with conventional tubular systems. They carry both the vertical and lateral loads mostly through axial forces in the grid members …”

Progressive collapse assessment of new hexagrid structural system for tall buildings

“…Two computer models of 28‐story and 48‐story buildings with diagrid and hexagrid system were prepared to assess the potential for progressive collapse (Figures and ). To use efficient diagonal angle for the diagrid system, according to Moon's (2007), Kim's () and Mashhadiali's () conclusions that illustrated that optimal angle lays between 65° and 75°, based on the architectural configuration, the angle of 66° were chosen for diagrid structures. In both systems, the cross‐section of the internal members is the same.…”

“…Push down results report that the hexagrid system is more ductile than the diagrids. According to previous researches (Mashhadiali and Kheyroddin, , ), the push over results indicates that hexagrids are more ductile than diagrids laterally. In this study, push down curves illustrate that ductility in hexagrid system is more than diagrids, vertically.…”

“…Among all systems, the diagrid structural system has attracted the attention of designers as a common structural system in tall buildings, due to its tubular behavior and architectural pleasure. Recently, an innovative structural system, called ‘hexagrid’, which was first introduced as a new structural system by Mashhadiali and Kheyroddin (, ), has been added to the tubular structural systems. Its configuration consists of multiple hexagonal grids on the face of the building.…”

“…Mashhadiali and Kheyroddin (, ) investigated the seismic behavior and wind‐induced response of the hexagrid and diagrid systems in tall buildings. They stated that the advantages of the hexagrid system were briefly the following: desirable architecture, enough flexibility, sensitive stiffness (pushing the limit height), simple tension and compression behavior, high shear mode of deflection, great ductility and multiple structural system.…”