A diagrid (short for *diagonal grid*) is a load-bearing structure made of a network of inclined, triangular members along the exterior of a building. The diagonals carry both vertical loads (self-weight) and horizontal forces (wind, seismic), so conventional columns are no longer needed and large, column-free floor plans become possible.
How does a diagrid work?
In a conventional skeleton frame, columns stand vertically and horizontal forces are taken to the foundation by separate stability elements (core, bracing or shear walls). In a diagrid, the inclined members do both jobs at once:
- Vertical compression is led down the diagonals to the foundation
- Horizontal forces are resisted by the same triangular network — a triangle is geometrically stable and cannot deform
- Bending moments are limited, because the members carry mostly axial (compression or tension) loads
Application
Diagrids are mainly used in:
- High-rise buildings — Hearst Tower (New York), 30 St Mary Axe (“The Gherkin”, London) and CCTV Tower (Beijing) are iconic examples
- Atriums and office buildings — for large, column-free interior spaces
- Curved or twisted shapes — the triangular grid easily follows complex geometry
- Steel roofs and domes — used as a three-dimensional truss
Advantages and disadvantages
Advantages:
- 20–30% material savings compared with a conventional skeleton
- No separate stability core required
- Distinctive architectural appearance
- Flexible interior layout
Disadvantages:
- Complex node connections — each joint must link many members at different angles
- Higher engineering and fabrication costs
- The diagonals cross window openings and must be coordinated carefully with the facade
Related terms
- Skeleton frame
- Truss
- High-strength concrete
- Steel
- Structural engineering
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