Diagrid tube structures composed of straight diagonals with gradually varying angles

Abstract

This paper presents preliminary design guidelines specifically for diagrid tube structures composed of straight diagonals with gradually changing angles. A graphic approach to configurating a diagrid of this type is introduced, with two basic geometric variables involved, i.e. the bottom and top diagonal angles. In terms of both stiffness and strength design criteria, a methodology for calculating diagonal member sizes is developed and applied to a set of diagrid tube structures with height‐to‐width aspect ratios ranging from 3.6 to 9. The diagrid tube structures are designed with various combinations of bottom and top angles in order to investigate the effects of bottom and top angles on the material usage. Based on the results, the optimal values of bottom and top angles are suggested, then, the optimal geometries for diagrid tube structures with different aspect ratios are determined. This paper attempts to help the designer arrange the structurally efficient diagrid layout conveniently and perform approximate calculations of the diagonal member sizes. Copyright © 2010 John Wiley & Sons, Ltd.

Quantification of seismic performance factors of steel diagrid system

“…In all diagrid models, the interior frames are designed only for carrying gravity loads and thus are pin connected, so the lateral forces are carried by the perimeter diagonals . Connections are assumed having adequate stiffness, strength, and detailing to prevent failure before brace rupture .…”

“…Researches were also carried out on diagrids containing diagonals whose angles vary in the height of a building, which were initially introduced by Moon . Zhang et al studied diagrid structures composed of straight diagonals with gradually changing angles. They suggested an empirical formula to find the optimal top and bottom angles as a function of aspect ratio (H/B) for minimum material usage under wind load.…”

Diagrid: An innovative, sustainable, and efficient structural system

“…Zhang et al study diagonal arrangements in 30‐, 37‐, 45‐, 60‐, and 75‐story diagrids with aspect ratio in the 3.6–9 range and propose a varying diagonal angle that decreases from the bottom to the top of the structure. The suggested top and bottom diagonal angles are in the range of 35° to 80°.…”

“…Diagrids are known to have considerable lateral stiffness but smaller ductility compared to conventional tubular structures . Ductility is especially important for structures in seismic regions.…”

“…The word diagrid, a combination of diagonal and grid, was used by researchers as early as 1970 when they studied elastic and plastic behavior of simple rectangular uniform diagonal grids and tried to find formulas for their collapse loads . Recently, however, the design and linear and nonlinear behavior of tall diagrid structures have attracted several researchers …”