The document discusses the DiaGrid structural system for tall buildings. A DiaGrid system uses a design of triangulated steel beams and horizontal support rings to construct large buildings. It creates a structural system of triangles that provides stability and resistance to lateral loads. Some key benefits of the DiaGrid system include column-free interior spaces, resistance to overturning forces, simpler construction, and better load redistribution compared to braced frame structures. While effective for buildings up to 70 stories, the DiaGrid system involves complicated joint connections.

1. DiaGrid Systems
Structural System
for
Tall Buildings
By:
Drishti Batra
Jagmohan Garg

2. What is DiaGrid?
Diagrid (a portmanteau of diagonal grid) is a
design
• for constructing large buildings with steel that
creates triangular structures with horizontal
support rings.
• Is a system of triangulated beams, straight or
curved, and horizontal rings that together make
up a structural system for a skyscraper
• Similar in idea and execution to a typical moment
frame - just more evolved

3. Examples of DiaGrid

4. Lateral Resisting System
• This main structure is
composed of RC Core and
Steel Diagrid Column.
• RC Core behaves like a
Cantilever and Steel
DiaGrid resists shear
action.
• Acting together they make
the building stiff.

5. Member Design Plan
o DiaGrid Columns
– Behaves like 3-
dimensional box
resisting both Tension
and Compression
– Stress in DiaGrid Column
under Gravity load and
Lateral Load is shown in
figure alongside:

6. o Corner Columns
-Axial Forces transfer from the inclined column to
corner columns.
-Results in high stress concentration at corners.
-Circular shape is more efficient for resisting
buckling than square shaped corners.

7. o Perimeter Girders
-They comprise of ring structure at the periphery of
the building connected at the nodes which are
further connected with the DiaGrid columns.
First figure is with Corner Columns
Second figure is without Corner Columns

8. Node Design
• Under Vertical Load
• Under Horizontal Shear

9. Node Design for Swiss Re Tower

10. o Tie Beams
- Transfers load from RC
Core to the DiaGrid
Structures
- Unbalanced forces can
be resisted by ring
beams and tie beams.

11. Construction Sequence
• in-place steel shop welding
• lifting up piece by piece
• trial shop assembly of parts with
high strength bolts
• in-place welding
• setting up perimeter girders

12. Materials Used
• Steel
-steel is the typical material of choice due to its high
abilities to resist both tensile and compressive
forces
-usage of steel leads to complicated joints but now
prefabrication of joints is widely done, so the
problem is eliminated.
• Concrete w/steel
-expensive and slow construction

13. Design Studies

14. Difference between Conventional Exterior
Braced Frame Structures and Diagrid structures
• Conventional Vertical Columns
are eliminated in DiaGrid
Structures as compared to
Conventional Structures.
• DiaGrid Structures are much
more effective in minimizing
shear deformations.
• In DiaGrid Structures, the core
can be designed to carry only
gravity loads without any
bracings.

15. Relative Stiffness of DiaGrids and
Braced Core

16. Benefits of Diagrid System
• mostly column free exterior and interior generous
amounts of day lighting due to dearth of interior
columns and structure.
• Diagrid Structure resists overturning.
• roughly 1/5th reduction in steel possible
• simple construction techniques
• full exploitation of the structural material
• easy and efficient distribution of load
• free and clear, unique floor plans are possible
• aesthetically dominate and expressive
• economical for storeys upto 50-70.

17. Benefits of Redundancy in Diagrid
Redundancy in the DiaGrid
design is obvious
• It is this redundancy then that can
transfer load from a failed portion
of the structure to another
• Skyscraper structural failure, as it
is such an important prominent
topic, can be minimized in a
DiaGrid design
• A DiaGrid has better ability to
redistribute load than a Moment
Frame skyscraper. Therefore,
there is deserved appeal for the
DiaGrid in today’s landscape of
building.

18. A Few Limitations
• After 70 storeys, this system becomes
uneconomical.
• System comprises of complicated joints.

19. Conclusions
DiaGrid structures are more stable than the
conventional structures. They resist
overturning because they provide maximum
resistance against torsion. These increase the
architectural beauty..

20. References
• www.civilenggseminar.blogspot
• MOON, K., CONNOR, J. J. and FERNANDEZ, J. E.
(2007). Diagrid Structural Systems for Tall Buildings:
Characteristics and Methodology for Preliminary
Design, The Structural Design of Tall and Special
Buildings, Vol. 16.2, pp 205-230.
• MAURIZIO TORENO (2011). An overview on diagrid
structures for tall buildings, Structural Engineers World
Congress 2011.
• www.nordicsteel2009
• www.dsg.fgg
• www.sydney.edu.au

21. QUERIES?

22. THANK YOU!