1. Bundled tube structural systemBy
Umer Farooq
Presentation on

4. Bundled tube structural system
One of the most efficient structural systems against heavy wind loads is the bundled tube structural system
The first person to implement the bundled tube structural system was Fazlur Rahman Khan from Dhaka, Bangladesh with the design of the DeWitt-Chestnut Apartments in Chicago, Illinois.

5. Fazlur Rahman Khan
The landmark and iconic building that uses the bundled tube structural system is the Willis Tower (formerly known as the Sears Tower)

6. A Bundled Tube Structure
A bundled tube typically consists of a number of individual tubes interconnected to form a multicell tube, in which the frames in the lateral load direction resist the shears, while the flange frames carry most of the overturning moments.

7. Details on the Sears Tower:
The Willis Tower in Chicago used this design, employing nine tubes of varying height to achieve its distinct appearance. It consists of exterior framed tube stiffened by interior frames to reduce the effect of shear lag in the exterior columns.
Details on the Sears Tower:
No interior columns
110 stories
1,469′-0″ in height
Tallest building until 1996
Each structural tube = 75′-0″ x 75′-0″
Completed in 1974

9. Bundled Tube Structural System and how it effects the floor plan

13. Advantages of Bundled tube system
Sufficient lateral stiffness
Building acts as a unified system of stiffened tubes
Aesthetically appealing
The interaction between the individual tubes and the belt trusses at mechanical levels allows the building to attain its extreme height
These trusses take the gravity loads from above and redistribute them evenly onto the tubes below

14. The bundle tube design was not only highly efficient in economic terms, but it was also "innovative in its potential for versatile formulation of architectural space.
Efficient towers no longer had to be box-like; the tube-units could take on various shapes and could be bundled together in different sorts of groupings.
The bundled tube structure meant that "buildings no longer need be boxlike in appearance: they could become sculpture

17. Thank you 